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Sample records for stent technique study

  1. Combined-stent covered technique and single covered stent technique for transjugular intrahepatic porto-systemic shunt: a prospective randomized controlled study

    International Nuclear Information System (INIS)

    Wang Changming; Li Xuan; Fu Jun; Lu Xianjun; Luan Jingyuan; Li Tianrun; Zhao Jun; Dong Guoxiang

    2014-01-01

    Objective: To compare the technique of combined stents with that of single stent-graft for the construction of transjugular intrahepatic porto-systemic shunt (TIPS) and to discuss their clinical outcomes. Methods: During the period from April 2011 to Dec. 2012, a total of 30 patients with upper gastrointestinal bleeding due to portal hypertension were admitted to the hospital. TIPS procedure was carried out in all the 30 patients. The patients were randomly allocated into either combined-stent group (n=17) or stent-graft group (control group, n=13) on the basis of a computer-generated randomization sequence. The PSC quality control, the patency rate of portal vein branches and the shunts, the incidence of encephalopathy and the survival rate of the two groups were documented and analyzed. Results: Technical success rate was 100%. After the treatment, in both groups the PSG became significantly lower than the PSG determined before the treatment (P<0.000). According to quality control chart, the of combined stents was superior to stent-graft technique in effectively controlling PSG. Five days after TIPS, the ammonia level in the combined- stent group was significantly decreased (P=0.029), while in the control group the ammonia level showed no significant changes (P=0.065). One patient died shortly after TIPS. The median follow- up time was 181 days. During the follow-up period death occurred in 3 cases in each group. The difference in the survival rate between the two groups was no significant (P=0.906). Of the three patients who developed encephalopathy, two were in the combined-stent group and one was in the control group. After medication the symptoms of encephalopathy were relieved. The patency rate of the shunts was 100% and the re-bleeding rate was 0% for both groups. The patency rate of portal vein branches was significantly higher in the combined-stent group than that in the control group (P=0.039). Conclusion: For the construction of TIPS, the technique of

  2. Feasibility study for the investigation of Nitinol self-expanding stents by neutron techniques

    International Nuclear Information System (INIS)

    Rogante, M.; Pasquini, U.; Rosta, L.; Lebedev, V.

    2011-01-01

    In this paper, neutron techniques - in particular, small angle neutron scattering (SANS) and neutron diffraction (ND) - are considered for the non-destructive characterization of Nitinol artery stents. This roughly equiatomic (50Ni-50Ti at%) shape memory alloy (SMA) exhibits significant properties of superelasticity and biocompatibility that make it suitable to be typically used as smart material for medical implants and devices. Nitinol self-expanding artery stents, as permanent vascular support structures, supply an ideal option to bypass surgery, but they are submitted for the whole of patient's life to the dynamical stress of the artery pulsation and the aggression from the biological environment. These stents, consequently, can suffer from wear and fracture occurrence likely due to a variety of cyclic fatigue, overload conditions and residual stresses. Neutrons have recently become a progressively more important probe for various materials and components and they allow achieving information complementary to those obtained from the traditional microstructural analyses. The outputs from the preliminary works already carried out in this field consent to consider neutron techniques capable to contribute to the development of these crucial medical implants. The achievable results can yield trends adoptable in monitoring of the stent features. -- Research Highlights: → Neutron techniques can contribute to develop Nitinol self-expanding artery stents. → Neutrons investigations can help avoiding wear and fracture events in Nitinol stents. → Neutron techniques can yield trends adoptable in monitoring of Nitinol stent features. → SANS is able to perform a micro- and nano-scale characterization of Nitinol stents. → Neutron Diffraction helps assessing stresses due to the exercise in Nitinol stents.

  3. Endovascular stentectomy using the snare over stent-retriever (SOS technique: An experimental feasibility study.

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    Tareq Meyer

    Full Text Available Feasibility of endovascular stentectomy using a snare over stent-retriever (SOS technique was evaluated in a silicon flow model and an in vivo swine model. In vitro, stentectomy of different intracranial stents using the SOS technique was feasible in 22 out of 24 (92% retrieval maneuvers. In vivo, stentectomy was successful in 10 out of 10 procedures (100%. In one case self-limiting vasospasm was observed angiographically as a technique related complication in the animal model. Endovascular stentectomy using the SOS technique is feasible in an experimental setting and may be transferred to a clinical scenario.

  4. Outcomes of the single-stent versus kissing-stents technique in asymmetric complex aortoiliac bifurcation lesions.

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    Suh, Yongsung; Ko, Young-Guk; Shin, Dong-Ho; Kim, Jung-Sun; Kim, Byeong-Keuk; Choi, Donghoon; Hong, Myeong-Ki; Jang, Yangsoo

    2015-07-01

    This study investigated the outcomes of single-stent vs kissing-stents techniques in asymmetric complex aortoiliac bifurcation (ACAB) lesions. We retrospectively investigated 80 consecutive patients (69 males, 66.6 ± 8.7 years) treated with a single stent and 30 patients (26 males, 67.1 ± 7.7 years) treated with kissing stents for ACAB between January 2005 and December 2012 from a single-center cohort. A ACAB lesion was defined as a symptomatic unilateral common iliac artery stenosis (>50%) combined with intermediate stenosis (30%-50%) in the contralateral common iliac artery ostium. The primary end point was the primary patency of the ACAB. The baseline clinical characteristics did not differ significantly between the single-stent and the kissing-stents group. Technical success was achieved in all patients. The single-stent group required fewer stents (1.3 ± 0.5 vs 2.3 ± 0.8; P stent group (3%) required bailout kissing stents because of plaque shift to the contralateral side. The major complication rates were 8% in single-stent vs 13% in the kissing-stent group, which was similar (P = .399). At 3 years, the single-stent and kissing-stents group had similar rates of primary patency (89% vs 87%; P = .916) and target lesion revascularization-free survival (93% vs 87%; P = .462). The single-stent technique in ACAB was safe and showed midterm outcomes comparable with those of kissing stents. Considering the benefits, such as fewer stents, less bilateral femoral access, and the availability of contralateral access for future intervention, the single-stent technique may be an advantageous treatment option in ACAB. Copyright © 2015 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  5. 'Stent in a stent'--an alternative technique for removing partially covered stents following sleeve gastrectomy complications.

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    Vasilikostas, Georgios; Sanmugalingam, Nimalan; Khan, Omar; Reddy, Marcus; Groves, Chris; Wan, Andrew

    2014-03-01

    Endoscopic stenting is a relatively new technique for the treatment of post sleeve gastrectomy complications. Partially covered stents are used in this method to minimise the risk of migration but they are associated with difficulties with removal. Patients requiring emergency stenting following sleeve gastrectomy underwent insertion of a partially covered metallic stent. One month later, if the stent was not easily removable, a fully covered overlapping stent was inserted and the patient was readmitted 2 weeks later for removal of both stents. Four patients required stenting following sleeve gastrectomy leaks, and one patient required stenting for a stricture. In these cases, a 'stent in a stent' technique was used for removal. This technique allows the safe removal of partially covered stents inserted following sleeve gastrectomy complications.

  6. Classic crush and DK crush stenting techniques.

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    Zhang, Jun-Jie; Chen, Shao-Liang

    2015-01-01

    Clinical data have supported the advantages of the double kissing (DK) crush technique, which consists of stenting the side branch (SB), balloon crush, first kissing, stenting the main vessel (MV) and final kissing balloon inflation, for complex coronary bifurcation lesions compared to other stenting techniques. Careful rewiring from the proximal cell of the MV stent to make sure the wire is in the true lumen of the SB stent is key to acquiring optimal angiographic results. Balloon anchoring from the MV, alternative inflation and each kissing inflation using large enough non-compliant balloons at high pressure, and the proximal optimisation technique are mandatory to improve both angiographic and clinical outcomes. Stratification of a given bifurcation lesion is recommended before decision making.

  7. Stenting of the SFA - indications, techniques,

    International Nuclear Information System (INIS)

    Rieger, J.; Treitl, M.; Reiser, M.; Ruppert, V.

    2006-01-01

    Aggressive risk factor modification, change of eating habits, exercise programs, and forceful antiplatelet therapy are the most important tools for the treatment of PAOD in symptomatic patients suffering from intermittent claudication. There are however no guidelines for revascularization at this stage. Endovascular treatment has been increasingly utilized over the last decade and increasingly displaced vascular surgery. Amongst numerous endovascular techniques beside PTA, stents meanwhile play the most important role due to constant technical progress. Results regarding the rate of restenosis or patency rates still remain worse compared to other vascular beds. This paper gives a review over recent results, currently available stent techniques, and possible indications for the endovascular therapy of an artery, which has turned out to be the biggest ordeal for material and construction of stents. (orig.) [de

  8. Coronary and peripheral stenting in aorto-ostial protruding stents: The balloon assisted access to protruding stent technique.

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    Helmy, Tarek A; Sanchez, Carlos E; Bailey, Steven R

    2016-03-01

    Treatment of aorto-ostial in-stent restenosis lesions represents a challenge for interventional cardiologists. Excessive protrusion of the stent into the aorta may lead to multiple technical problems, such as difficult catheter reengagement of the vessel ostium or inability to re-wire through the stent lumen in repeat interventions. We describe a balloon assisted access to protruding stent technique in cases where conventional coaxial engagement of an aorto-ostial protruding stent with the guide catheter or passage of the guide wire through the true lumen is not feasible. This technique is applicable both in coronary and peripheral arteries. © 2015 Wiley Periodicals, Inc.

  9. T-configured Dual Stent Placement in Malignant Biliary Hilar Obstruction: Technique and Clinical Application

    International Nuclear Information System (INIS)

    Jeon, Yong Sik; Kim, Ji Hyung

    2010-01-01

    To evaluate implanting techniques of T-configured dual stents in malignant hilar obstruction and investigate the clinical factors related to stent obstruction. The study included 28 patients undergoing T-configured dual stent implantation to palliate malignant biliary hilar obstruction. The unilobar approach was first attempted in the procedure, which progressed to bilobar approach when it was found that the unilobar approach was not feasible. If the stent was again obstructed, clinical palliation was attempted using stent re-insertion or PTBD. Clinical factors associated with T-configured dual stenting were examined in the patients with stent re-obstruction, which was followed by a correlation between these clinical factors and stent obstruction. Eleven of 13 patients were successfully treated by the unilobar approach. The two unsuccessful cases sustained angulation of the central large mesh stent. For the bilobar approach, 14 of 15 patients were successfully treated. For the one unsuccessful patient, the stent failed to pass through the central large mesh. Stent obstruction was revealed in 13 patients during the follow-up period. Balloon-assisted stent re-canalization was successfully performed in 5 patients. The analysis suggests that no definite correlation was found between stent obstruction and the clinical factors associated with dual stent placement. Conversely, bile containing sludge or debris was significantly correlated to early stent obstruction. Technical adoption considering the bile duct anatomy and obstruction pattern is important for T-configured dual stent implantation. The prudent evaluation of bile juice characters and cholangiographic findings is required for the appropriate clinical application of the T-configured dual stenting

  10. Broken Esophageal Stent Successfully Treated by Interventional Radiology Technique

    International Nuclear Information System (INIS)

    Zelenak, Kamil; Mistuna, Dusan; Lucan, Jaroslav; Polacek, Hubert

    2010-01-01

    Esophageal stent fractures occur quite rarely. A 61-year-old male patient was previously treated for rupture of benign stenosis, occurring after dilatation, by implanting an esophageal stent. However, a year after implantation, the patient suffered from dysphagia caused by the broken esophageal stent. He was treated with the interventional radiology technique, whereby a second implantation of the esophageal stent was carried out quite successfully.

  11. Ureteral stent retrieval using the crochet hook technique in females.

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    Takashi Kawahara

    Full Text Available INTRODUCTION: We developed a method for ureteral stent removal in female patients that requires no cystoscopy or fluoroscopic guidance using a crochet hook. In addition, we also investigated the success rate, complications and pain associated with this procedure. METHODS: A total of 40 female patients (56 stents underwent the removal of ureteral stents. All procedures were carried out with the patients either under anesthesia, conscious sedation, or analgesic suppositories as deemed appropriate for each procedure including Shock Wave Lithotripsy (SWL, Ureteroscopy (URS, Percutaneous Nephrolithotomy (PCNL, and ureteral stent removal. At the time of these procedures, fluoroscopy and/or cystoscopy were prepared, but they were not used unless we failed to successfully remove the ureteral stent using the crochet hook. In addition, matched controls (comprising 50 stents which were removed by standard ureteral stent removal using cystoscopy were used for comparison purposes. RESULTS: A total of 47 of the 56 stents (83.9% were successfully removed. In addition, 47 of 52 (90.4% were successfully removed except for two migrated stents and two heavily encrusted stents which could not be removed using cystoscopy. Ureteral stent removal using the crochet hook technique was unsuccessful in nine patients, including two encrustations and two migrations. Concerning pain, ureteral stent removal using the crochet hook technique showed a lower visual analogue pain scale (VAPS score than for the standard technique using cystoscopy. CONCLUSIONS: Ureteral stent removal using a crochet hook is considered to be easy, safe, and cost effective. This technique is also easy to learn and is therefore considered to be suitable for use on an outpatient basis.

  12. Intravascular stent graft with polyurethane and metallic stent: experimental study

    International Nuclear Information System (INIS)

    Do, Young Soo; Lee, Won Jae; Kim, Boo Kyung Han; Park, Jae Hyung; Lee, Hak Jong; Lee, Sang Hyun; Kim, Sung Hyun; Kim, Jong Won; Ha, Jongwon

    1997-01-01

    To evaluate the usefulness of a new model of the stent graft, and of tissue response related to placement of the stent graft. The stent graft was constructed from polyurethane (Pellethane) graft and Hanaro stent(12mm in diameter, 45mm in length, 10 bends). A stent grafts was inserted into the lower thoracic aorta in each of six adult mongrel dogs(body weight, 12-16kg). At one, two, four, and six months, follow-up studies of angiography and spiral CT angiography were preformed to evaluate wascular patency, vascular stenosis, and thrombus formation. Two dogs were sacrificed at 1month, 2months, and 6months after insertion of the stent graft and macroscopic, light microscopic, and scanning electron microscopic examinations of the aortic segment including the stent graft were performed to evaluate intimal hyperplasia, endothelial growth to the graft, and thrombus formation. During follow-up at one, two, four, and six months, angiography or spiral CT angiography showed 20-100% luminal stenosis or occlusion of the lower thoracic aorta by the thrombus and perigraft leaks in three dogs(50%), and collateral vessels caused by occlusion of the aorta in two (33.3%). On gross examination, there were thrombi of 1-5mm thickness at the graft portions in all dogs, and this thickness gradually increased. The mean thickness of intimal hyperplasia at the stent portion gradually increased from 120μm to 227μm and the mean thickness of intimal hyperplasia at the graft portion from 93μm to 914μm. This thickness was greater at the graft portion than at the stent portion. Scanning electron microscopy showed elliptical endothelial lining on the neointimal surfaces at each end of the graft. Thrombi caused stenosis or occlusion of the stent graft. In order for such a graft to be ideal, further study is needed

  13. Subintimal Recanalization of Occluded Stents: The Substent Technique

    International Nuclear Information System (INIS)

    Diamantopoulos, Athanasios; Katsanos, Konstantinos; Spiliopoulos, Stavros; Karnabatidis, Dimitris; Siablis, Dimitris

    2013-01-01

    PurposeApplication of metal stents is complicated by neointimal hyperplasia leading to vessel restenosis and reocclusion. Treatment options in cases presenting with complete occlusion of the stented segment and recurrent critical limb ischemia (CLI) are limited. We present the option of the subintimal/substent technique in dealing with occluded stents.MethodsThe study included patients presenting with recurrent CLI due to impaired blood flow as a result of complete occlusion of previously inserted metal stents and unsuccessful intraluminal crossing of the lesion via either the antegrade or retrograde approach. In these cases, crossing the occlusion through the subintimal/substent plane was attempted. Primary end points included technical success, safety of the procedure, clinical improvement, and limb salvage, while secondary end points were patient survival, primary patency, and vessel restenosis rates at 1-year follow-up. Study end points were calculated by Kaplan–Meier survival analysis.ResultsBetween July 2006 and October 2011, a total of 14 patients (mean age 69.14 ± 12.59 years, 12 men) were treated with the substent technique and included in the analysis. Technical success rate was 85.71 % (12 of 14), with a total lesion length of 193.57 ± 90.78 mm. The mean occluded stented segment length was 90.21 ± 44.34 mm. In 10 (83.33 %) of 12 cases, a new stent had to be placed by the side of the old occluded one, while the remaining two cases (16.67 %) were treated only with balloon angioplasty. No serious adverse events were noted during the immediate postprocedural period. All successfully treated patients improved clinically. Estimated limb salvage was 90.9 %, and patient survival rate was 90.0 % at 1 year’s follow-up. Primary patency was 45.50 % and vessel restenosis 77.30 %.ConclusionSubintimal recanalization of occluded metal stents through the substent plane is a valuable alternative treatment option, especially in patients with recurrent CLI with few

  14. Percutaneous nephrostomy and antegrade ureteral stenting: technique - indications - complications

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    Hausegger, Klaus A. [Klagenfurt General Hospital, Department of Radiology, Klagenfurt (Austria); Portugaller, Horst R. [University Hospital of Graz, Department of Radiology, Graz (Austria)

    2006-09-15

    In this review the technique, indication for and complications of percutaneous nephrostomy (PCN) and antegrade ureter stent insertion are described. In the majority of the cases PCN is performed to relieve urinary obstruction, which can be of benign or malignant nature. Another indication for PCN is for treatment of urinary fistulas. PCN can be performed under ultrasound and/or fluoroscopic guidance, with a success rate of more than 90%. The complication rate is approximately 10% for major and minor complications together and 4-5% for major complications only. Percutaneous antegrade double-J stent insertion usually is performed if retrograde ureter stenting has not been successful. However, especially in malignant obstructions, the success rate for antegrade stenting is higher than for retrograde transvesical double-J stent insertion. In the case of severe infection and bleeding after PCN JJ-stent insertion may be contraindicated so long as there is no sufficient concomitant drainage via a PCN. Lower urinary tract dysfunction should be excluded before stent placement. The complication rate is 2-4%. Consequent stent surveillance with regular stent exchange is mandatory. (orig.)

  15. The technique study and primary clinical application of inverted Y-shaped self-expandable metal airway stent

    International Nuclear Information System (INIS)

    Han Xinwei; Wu Gang; Ma Ji; Yang Ruimin; Guan Sheng; Ma Nan; Wang Yanli

    2007-01-01

    Objective: To investigate the feasibility and primary therapeutic effect of inverted Y-shaped self-expandable metal stent for complex airway stenosis. Methods: On the standpoint of the peculiar anatomic structure and the pathological changes of complex airway stenosis, we designed the inverted Y-shaped self-expandable metal stent. Under the fluoroscopic guidance, 7 stents were implanted in 7 cases of airway complex stenosis. Results: The inverted Y-shaped self-expandable metal stents were placed seccussfully, with instantaneous relief of dyspnea and improvement of living quality. Conclusion: The placement of inverted Y-shaped self-expandable metal stent is feasible and safe for treating airway complex stenosis. (authors)

  16. Combined antegrade and retrograde ureteral stenting: the rendezvous technique

    International Nuclear Information System (INIS)

    Macri, A.; Magno, C.; Certo, A.; Basile, A.; Scuderi, G.; Crescenti, F.; Famulari, C.

    2005-01-01

    Ureteral stenting is a routine procedure in endourology. To increase the success rate in difficult cases, it may be helpful to use the rendezvous technique, a combined antegrade and retrograde approach. We performed 16 urological rendezvous in 11 patients with ureteral strictures or urologic lesions. The combined approach was successful in all patients, without morbidity or mortality. In our experience the rendezvous technique increased the success rate of antegrade ureteral stenting from 78.6 to 88.09% (p>0.05). This procedure is a valid option in case of failure of conventional ureteral stenting

  17. Carotid angioplasty and stenting under protection. Techniques, results and limitations.

    Science.gov (United States)

    Henry, M; Polydorou, A; Henry, I; Anagnostopoulou, I S; Polydorou, I A; Hugel, M

    2006-10-01

    A carotid stenosis is responsible for about 30% of strokes occurring. Carotid endarterectomy (CEA) is considered to be the gold standard treatment of a carotid stenosis. Carotid angioplasty and stenting (CAS) is emerging as a new alternative treatment for a carotid artery stenosis, but the risk of neurological complications and brain embolism remains the major drawback to this procedure. Therefore, in order to reduce the risks, we need: 1) good indications, good patient and lesion selection; 2) correct techniques; 3) brain protection devices (cerebral protection devices should be routinely used and are mandatory for any procedure); 4) 3 types of protection devices are available, but filters are the most commonly used (all protection devices have limitations and cannot prevent from all embolic events; however, neurological complications can be reduced by 60%); 5) a good choice of the stent and correct implantation (all stents are not equivalent and have different geometrical effects); 6) pharmacological adjuncts; 7) a good team. Recent studies have shown that CAS has superior short-term outcomes than CEA in high surgical risk patients, but there are enough reported data to conclude that CAS is also not inferior to CEA in low-risk patients. CAS under protection is the standard of care and is maybe becoming the gold standard treatment of a carotid stenosis at least in some subgroups of patients.

  18. [Comparison of DK crush with classical crush technique with drug-eluting stents for the treatment of coronary bifurcation lesions from DKCRUSH-1 study].

    Science.gov (United States)

    Chen, Shao-liang; Zhang, Jun-jie; Ye, Fei; Chen, Yun-dai; Lü, Shu-zheng; Tan, Huaycheem; Patel, Tejas; Kenji, Kawajiri; Tamari, Israel; Shan, Shou-jie; Zhu, Zhong-sheng; Lin, Song; Tian, Nai-liang; Li, Xiao-bo; Liu, Zhi-zhong; Lee, Michael; Wei, Meng; Xu, Ya-wei; Yuan, Zheng-bai; Qian, Jun; Sun, Xue-wen; Yang, Song; Chen, Jin-guo; He, Ben; Sumit, Suji

    2008-02-01

    To determine independent factors correlated with clinical effects of DK crush and classical crush technique with drug-eluting stents on bifurcation lesions. 311 patients with bifurcation lesions were randomized to classical (C, n = 156) or double kissing (DK) crush (n = 155) stent implantation group. The primary endpoints included major adverse cardiac events (MACE). Final kissing balloon inflation (FKBI) success rate was 76% in C and 100% in DK groups (P DK crush procedure was characterized by lower unsatisfactory FKBI rate (27.6% vs.6.3%, P DK groups (P = 0.01), respectively. Cumulative 8-month MACE was 35.9% in without-FKBI and 19.7% in with-FKBI sub-groups, and 11.4% in DK group (P = 0.02). The incidence of stent thrombosis was 3.2% in C group (5.1% without vs. 1.7% with FKBI) and 1.3% in DK group (P > 0.05). The predictive factors of MACE included minimal side branch stent lumen diameter and lack of DK crush technique. DK crush technique is an alternative of double stenting techniques in terms of improvement of restenosis and clinical outcomes.

  19. Biodegradable Magnesium Stent Treatment of Saccular Aneurysms in a Rat Model - Introduction of the Surgical Technique.

    Science.gov (United States)

    Nevzati, Edin; Rey, Jeannine; Coluccia, Daniel; D'Alonzo, Donato; Grüter, Basil; Remonda, Luca; Fandino, Javier; Marbacher, Serge

    2017-10-01

    The steady progess in the armamentarium of techniques available for endovascular treatment of intracranial aneurysms requires affordable and reproducable experimental animal models to test novel embolization materials such as stents and flow diverters. The aim of the present project was to design a safe, fast, and standardized surgical technique for stent assisted embolization of saccular aneurysms in a rat animal model. Saccular aneurysms were created from an arterial graft from the descending aorta.The aneurysms were microsurgically transplanted through end-to-side anastomosis to the infrarenal abdominal aorta of a syngenic male Wistar rat weighing >500 g. Following aneurysm anastomosis, aneurysm embolization was performed using balloon expandable magnesium stents (2.5 mm x 6 mm). The stent system was retrograde introduced from the lower abdominal aorta using a modified Seldinger technique. Following a pilot series of 6 animals, a total of 67 rats were operated according to established standard operating procedures. Mean surgery time, mean anastomosis time, and mean suturing time of the artery puncture site were 167 ± 22 min, 26 ± 6 min and 11 ± 5 min, respectively. The mortality rate was 6% (n=4). The morbidity rate was 7.5% (n=5), and in-stent thrombosis was found in 4 cases (n=2 early, n=2 late in stent thrombosis). The results demonstrate the feasibility of standardized stent occlusion of saccular sidewall aneurysms in rats - with low rates of morbidity and mortality. This stent embolization procedure combines the opportunity to study novel concepts of stent or flow diverter based devices as well as the molecular aspects of healing.

  20. Stent-in-Stent Technique for the Treatment of Proximal Bronchial Restenosis after Insertion of Metallic Stents: A Report of Two Cases

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    Benjamin Bondue

    2016-01-01

    Full Text Available Endoscopic treatment of a bronchial restenosis previously treated by insertion of a partially covered self-expandable metallic stent (SEMS can be difficult. Classically, after recanalization of the bronchus, the stent is removed and replaced by a more adapted one. We report on two cases of proximal bronchial restenosis treated by insertion of an additional stent inside the lumen of the previously inserted stent using the stent-in-stent (SIS technique. The indications for the initial stent were malignancy in Patient 1 and posttransplant bronchial stenosis in Patient 2. Restenosis occurred at the proximal end of the stent within months in both cases. Stent removal and insertion of a new stent were considered, but this option was discarded because of an excessive risk of bronchial perforation and preference towards an alternative approach. In both cases, a second customized SEMS was placed using the SIS technique after ablation of the proximal end stenosis of the stent by argon plasma coagulation and/or dilation with a balloon. Recanalization of the bronchus was achieved in both cases without complications. The SIS technique is a valuable alternative to removal of SEMS in case of proximal bronchial restenosis.

  1. A novel application of the culotte stent technique to bail out a jailed common iliac artery

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    Hideto Sangen, MD

    2017-12-01

    Full Text Available Implanting a self-expandable stent at the ostium of the common iliac artery (CIA may lead to coverage of the orifice of the contralateral CIA. Here, we describe a novel application of the culotte stent technique using a balloon-expandable stent to bail out an ostial stenotic legion of a jailed CIA due to prior self-expandable stent placement. The bilateral CIAs were revascularized by culotte stenting, and patency of the stents was confirmed 3 years after the procedure. The culotte stent technique was successfully applied to an ostial stenotic lesion of a jailed CIA.

  2. A novel balloon assisted two-stents telescoping technique for repositioning an embolized stent in the pulmonary conduit.

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    Kobayashi, Daisuke; Gowda, Srinath T; Forbes, Thomas J

    2014-08-01

    A 9-year-old male, with history of pulmonary atresia and ventricular septal defect, status post complete repair with a 16 mm pulmonary homograft in the right ventricular outflow tract (RVOT) underwent 3110 Palmaz stent placement for conduit stenosis. Following deployment the stent embolized proximally into the right ventricle (RV). We undertook the choice of repositioning the embolized stent into the conduit with a transcatheter approach. Using a second venous access, the embolized stent was carefully maneuvered into the proximal part of conduit with an inflated Tyshak balloon catheter. A second Palmaz 4010 stent was deployed in the distal conduit telescoping through the embolized stent. The Tyshak balloon catheter was kept inflated in the RV to stabilize the embolized stent in the proximal conduit until it was successfully latched up against the conduit with the deployment of the overlapping second stent. One year later, he underwent Melody valve implantation in the pre-stented conduit relieving conduit insufficiency. This novel balloon assisted two-stents telescoping technique is a feasible transcatheter option to secure an embolized stent from the RV to the RVOT. © 2014 Wiley Periodicals, Inc.

  3. Biliary and pancreatic stenting: Devices and insertion techniques in therapeutic endoscopic retrograde cholangiopancreatography and endoscopic ultrasonography

    Science.gov (United States)

    Mangiavillano, Benedetto; Pagano, Nico; Baron, Todd H; Arena, Monica; Iabichino, Giuseppe; Consolo, Pierluigi; Opocher, Enrico; Luigiano, Carmelo

    2016-01-01

    Stents are tubular devices made of plastic or metal. Endoscopic stenting is the most common treatment for obstruction of the common bile duct or of the main pancreatic duct, but also employed for the treatment of bilio-pancreatic leakages, for preventing post- endoscopic retrograde cholangiopancreatography pancreatitis and to drain the gallbladder and pancreatic fluid collections. Recent progresses in techniques of stent insertion and metal stent design are represented by new, fully-covered lumen apposing metal stents. These stents are specifically designed for transmural drainage, with a saddle-shape design and bilateral flanges, to provide lumen-to-lumen anchoring, reducing the risk of migration and leakage. This review is an update of the technique of stent insertion and metal stent deployment, of the most recent data available on stent types and characteristics and the new applications for biliopancreatic stents. PMID:26862364

  4. Endovascular Management of Aorta-Iliac Stenosis and Occlusive Disease by Kissing-Stent Technique

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    Meng Liu

    2016-01-01

    Full Text Available Kissing-stenting treatment has been used to treat patients with peripheral artery disease (PAD. However, the long term efficacy of the stenting therapy is not well defined in Chinese PAD patients. To investigate the question, sixty-three PAD patients (37 males and 26 females, aged 66±7.3 years, were analysed in the study. They were featured as claudication (n=45, 71.4%, rest pain (n=18, 28.6%, or gangrene (n=8, 12.7%. In total, 161 stents were applied in aorta-iliac lesions with 2.6 stents for each patient, including 55 self-expanding stents, 98 balloon expandable stents, and 8 covered stents. The success rate of implanting Kissing-stents was 100%. Catheter-directed thrombolysis (CDT with urokinase was performed in 8 cases (12.7%. The severity of peripheral ischemia was significantly improved, as evidenced by 3.3-fold increase of ankle-brachial pressure index (ABI after the surgery (P=0.008. One, three, five, and seven years after surgery, the primary patency rate was 87.3%, 77.4%, 71.1%, and 65.0%, whereas the secondary patency rate was 95.2%, 92.5%, 89.5%, and 85.0%, respectively. No in-hospital mortality was recorded. In conclusion, Kissing-stenting technique for aorta-iliac lesions is safe and effective with lower complications. It is beneficial for aorta-iliac occlusions that are longer than 60 mm.

  5. Antegrade jj stenting after percutaneous renal procedures: The ‘pull and push’ technique

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    Ratkal, Jaideep M.; Sharma, Elias

    2014-01-01

    A JJ stent is inserted antegradely after percutaneous renal procedures like percutaneous nephrolithotomy (PCNL) for renal calculus disease, and for endopyelotomy for pelvi-ureteric junction obstruction. We describe a technique for antegrade stent insertion after PCNL. PMID:26413327

  6. Antegrade jj stenting after percutaneous renal procedures: The 'pull and push' technique.

    Science.gov (United States)

    Ratkal, Jaideep M; Sharma, Elias

    2015-06-01

    A JJ stent is inserted antegradely after percutaneous renal procedures like percutaneous nephrolithotomy (PCNL) for renal calculus disease, and for endopyelotomy for pelvi-ureteric junction obstruction. We describe a technique for antegrade stent insertion after PCNL.

  7. Stent

    Science.gov (United States)

    ... Drugs & Supplements Videos & Tools Español You Are Here: Home → Medical Encyclopedia → Stent URL of this page: //medlineplus.gov/ency/article/002303.htm Stent To use the sharing features on this page, please enable JavaScript. A stent is a tiny tube placed into a hollow structure in your ...

  8. Stent tunnel technique to save thrombosed native hemodialysis fistula with extensive venous aneurysm

    Directory of Open Access Journals (Sweden)

    Rabellino M

    2017-07-01

    Full Text Available Martin Rabellino,1 Guillermo J Rosa-Diez,2 Sergio A Shinzato,1 Pablo Rodriguez,1 Oscar A Peralta,1 Maria S Crucelegui,2 Rosario Luxardo,2 Agustina Heredia-Martinez,2 Mariela I Bedini-Rocca,2 Ricardo D García-Mónaco1 1Department of Angiography and Endovascular Therapy, 2Department of Nephrology, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina Introduction and purpose: The increasing number of patients undergoing hemodialysis and the limited number of access sites have resulted in an increasing number of techniques to maintain vascular access for hemodialysis. Thrombosed arteriovenous (AV fistulas with large venous aneurysms have poor treatment results, with both endovascular and surgical techniques, leading to a high rate of definitive AV access loss. The purpose of this study was to review the feasibility and initial results of this novel endovascular treatment of thrombosed AV fistulas with large venous aneurysms.Materials and methods: A novel endovascular treatment technique of inserting nitinol auto-expandable uncovered stents stretching through the whole puncture site area, thus creating a tunnel inside the thrombus, was retrospectively analyzed and described.Results: A total of 17 stents were placed in 10 hemodialysis fistulas, with a mean venous coverage length of 17.8 cm. In all the cases, 100% technical success was achieved, with complete restoration of blood flow in all patients. There were no procedure-related complications. The mean follow-up was 167 days (range 60–420 days, with a primary and assisted patency of 80% and 100%, respectively. No multiple trans-stent struts-related complications were observed. Three stent fractures were diagnosed with plain films at the site of puncture without consequence in the venous access permeability.Conclusion: The “stent tunnel technique” is a feasible, safe and effective alternative to salvage native hemodialysis access, thus extending the function of the venous access with

  9. Compliance Study of Endovascular Stent Grafts Incorporated with Polyester and Polyurethane Graft Materials in both Stented and Unstented Zones

    Directory of Open Access Journals (Sweden)

    Ying Guan

    2016-08-01

    Full Text Available Compliance mismatch between stent graft and host artery may induce complications and blood flow disorders. However, few studies have been reported on stent graft compliance. This study aims to explore the deformation and compliance of stent graft in stented and unstented zones under three pressure ranges. Compliance of two stent grafts incorporated with polyurethane graft (nitinol-PU and polyester graft (nitinol-PET materials respectively were tested; the stents used in the two stent grafts were identical. For the circumferential deformation of the stent grafts under each pressure range, the nitinol-PET stent graft was uniform in both zones. The nitinol-PU stent graft was circumferentially uniform in the stented zone, however, it was nonuniform in the unstented zone. The compliance of the PU graft material was 15 times higher than that of the PET graft. No significant difference in compliance was observed between stented and unstented zones of the nitinol-PET stent graft regardless of the applied pressure range. However, for the nitinol-PU stent graft, compliance of the unstented PU region was approximately twice that of the stented region; thus, compliance along the length of the nitinol-PU stent graft was not constant and different from that of the nitinol-PET stent graft.

  10. Improved coronary in-stent visualization using a combined high-resolution kernel and a hybrid iterative reconstruction technique at 256-slice cardiac CT—Pilot study

    International Nuclear Information System (INIS)

    Oda, Seitaro; Utsunomiya, Daisuke; Funama, Yoshinori; Takaoka, Hiroko; Katahira, Kazuhiro; Honda, Keiichi; Noda, Katsuo; Oshima, Shuichi; Yamashita, Yasuyuki

    2013-01-01

    Objectives: To investigate the diagnostic performance of 256-slice cardiac CT for the evaluation of the in-stent lumen by using a hybrid iterative reconstruction (HIR) algorithm combined with a high-resolution kernel. Methods: This study included 28 patients with 28 stents who underwent cardiac CT. Three different reconstruction images were obtained with: (1) a standard filtered back projection (FBP) algorithm with a standard cardiac kernel (CB), (2) an FBP algorithm with a high-resolution cardiac kernel (CD), and (3) an HIR algorithm with the CD kernel. We measured image noise and kurtosis and used receiver operating characteristics analysis to evaluate observer performance in the detection of in-stent stenosis. Results: Image noise with FBP plus the CD kernel (80.2 ± 15.5 HU) was significantly higher than with FBP plus the CB kernel (28.8 ± 4.6 HU) and HIR plus the CD kernel (36.1 ± 6.4 HU). There was no significant difference in the image noise between FBP plus the CB kernel and HIR plus the CD kernel. Kurtosis was significantly better with the CD- than the CB kernel. The kurtosis values obtained with the CD kernel were not significantly different between the FBP- and HIR reconstruction algorithms. The areas under the receiver operating characteristics curves with HIR plus the CD kernel were significantly higher than with FBP plus the CB- or the CD kernel. The difference between FBP plus the CB- or the CD kernel was not significant. The average sensitivity, specificity, and positive and negative predictive value for the detection of in-stent stenosis were 83.3, 50.0, 33.3, and 91.6% for FBP plus the CB kernel, 100, 29.6, 40.0, and 100% for FBP plus the CD kernel, and 100, 54.5, 40.0, and 100% for HIR plus the CD kernel. Conclusions: The HIR algorithm combined with the high-resolution kernel significantly improved diagnostic performance in the detection of in-stent stenosis

  11. A scanning electron microscopic study of biliary stent materials

    NARCIS (Netherlands)

    van Berkel, A. M.; van Marle, J.; van Veen, H.; Groen, A. K.; Huibregtse, K.

    2000-01-01

    Clogging of biliary stents remains an important problem. In vitro studies have shown less sludge formation in Teflon stents. Recently, clinical studies with Teflon stents have produced contradictory results. The aim of this study was to investigate whether the surface properties of the

  12. Reverse waffle cone technique in management of stent dislodgement into intracranial aneurysms.

    Science.gov (United States)

    Luo, Chao-Bao; Lai, Yen-Jun; Teng, Michael Mu-Huo; Chang, Feng-Chi; Lin, Chung-Jung; Guo, Wan-Yuo

    2013-09-01

    Stent-assisted coil embolization (SACE) is a common method to manage intracranial wide-neck aneurysm. Using this technique, a stent must be successfully deployed into the parent artery to cross the aneurysm neck. We describe the reverse waffle cone technique in management of intra-procedural stent dislodgement during SACE of internal carotid artery (ICA) wide-neck aneurysms. Two patients with unruptured wide-neck ICA aneurysms underwent SACE. Intra-procedural forward stent migration occurred during catheterization with proximal stent dislodgement and migration into the aneurysm sac. Navigation of a second stent to bridge the aneurysm neck failed in one patient because the second stent was impeded by the dislodged stent. Using the reverse waffle cone technique, a microcatheter was navigated into the aneurysm sacs. Coils were safely detached into each aneurysm sac without any device assistance. The two wide-neck aneurysms were successfully treated with preservation of flow to the internal carotid arteries. The complication of intra-procedural distal stent migration and dislodgement, with proximal stent prolapse into an aneurysm sac, may not result in a failure to coil the aneurysm. The reverse waffle cone technique provides an effective treatment in the management of this complication. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Mechanisms of Biliary Plastic Stent Occlusion and Efforts at Prevention

    Directory of Open Access Journals (Sweden)

    Chang-Il Kwon

    2016-03-01

    Full Text Available Biliary stenting via endoscopic retrograde cholangiopancreatography has greatly improved the quality of patient care over the last 30 years. Plastic stent occlusion limits the life span of such stents. Attempts to improve plastic stent patency duration have mostly failed. Metal stents (self-expandable metal stents [SEMSs] have therefore replaced plastic stents, especially for malignant biliary strictures. SEMS are at least 10 times more expensive than plastic stents. In this focused review, we will discuss basic mechanisms of plastic stent occlusion, along with a systematic summary of previous efforts and related studies to improve stent patency and potential new techniques to overcome existing limitations.

  14. New techniques for stenting severely strictured or occluded ureters

    Energy Technology Data Exchange (ETDEWEB)

    Mygind, T; Dorph, S; Nielsen, H; Nielsen, L

    1985-11-01

    Percutaneous stenting of the severely strictured ureter is facilitated by catheterization through a rigid curved tube leading through the kidney. Alternatively, bidirectional traction tensioning of a guide wire pulled through the entire urinary tract permits antegrade dilatation and stent drainage. Complete occlusion near the ureteric orifice may be bypassed by transureteral puncture of the bladder followed by stent insertion.

  15. Crossing Y-stent technique with dual open-cell stents for coiling of wide-necked bifurcation aneurysms.

    Science.gov (United States)

    Ko, Jun Kyeung; Han, In Ho; Cho, Won Ho; Choi, Byung Kwan; Cha, Seung Heon; Choi, Chang Hwa; Lee, Sang Weon; Lee, Tae Hong

    2015-05-01

    Double stenting in a Y-configuration is a promising therapeutic option for wide-necked cerebral aneurysms not amenable to reconstruction with a single stent. We retrospectively evaluated the efficacy and safety of the crossing Y-stent technique for coiling of wide-necked bifurcation aneurysms. By collecting clinical and radiological data we evaluated from January 2007 through December 2013, 20 wide-necked bifurcation aneurysms. Twelve unruptured and eight ruptured aneurysms in 20 patients were treated with crossing Y-stent-assisted coiling. Aneurysm size and neck size ranged from 3.2 to 28.2mm (mean 7.5mm) and from 1.9 to 9.1mm (mean 4.5mm). A Y-configuration was established successfully in all 20 patients. All aneurysms were treated with a pair of Neuroform stents. The immediate angiographic results were total occlusion in 17 aneurysms, residual neck in two, and residual sac in one. Peri-operative morbidity was only 5%. Fifteen of 18 surviving patients underwent follow-up conventional angiography (mean, 10.9 months). The result showed stable occlusion in all 15 aneurysms and asymptomatic in-stent occlusion in one branch artery. At the end of the observation period (mean, 33.5 months), all 12 patients without subarachnoid hemorrhage had excellent clinical outcomes (mRS 0), except one (mRS 2). Of eight patients with subarachnoid hemorrhage, four remained symptom free (mRS 0), while the other four had were dependent or dead (mRS score, 3-6). In this report on 20 patients, crossing Y-stent technique for coiling of wide-necked bifurcation aneurysms showed a good technical safety and favorable clinical and angiographic outcome. Copyright © 2015. Published by Elsevier B.V.

  16. New expandable metallic stents: An experimental study in vessels of dogs

    International Nuclear Information System (INIS)

    Song, Ho Young; Lee, Jung Min; Chung, Jin Young; Chung, Gyung Ho; Kim, Bog Yi; Kuh, Ja Houng

    1992-01-01

    Three-types of expandable metallic stents were constructed to evaluate the differences between the stents: one, formed in a cylindrical zigzag pattern wth stainless steel wire (Gianturco stent), another, made by coating the Gianturco stent with silicone rubber (Silicone stent), the third, made by coating the Gianturco stent with 24 carat gold (Gold stent) for tissue acceptance. A total of 69 stents (each 23 stents of Gianturco, Silicone, and Gold stents) of 8-12 mm in diameter and 20 mm long were placed into normal abdominal aorta, inferior vena cava and lilac artery of nine adults dogs for 2 weeks to 11 months. It was more difficult to introduce Silicone stent into an introducing sheath than Gianturco or Gold stent due to the thickness of silicone rubber. Four Gianturco stents and three Silicone stents showed migration but Gold stent did not. Luminal narrowing or occlusion was noted in 3 Silicone stents. In 2 Gianturco stents, and in 1 Gold stent. Neointimal proliferation over the stent wires was more rapid and even in Gold stent than Silicone or Gianturco stent. Although further study is needed, Gold stent seems to be better than Gianturco or Silicone stent as an endovascular graft material

  17. New expandable metallic stents: An experimental study in vessels of dogs

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ho Young; Lee, Jung Min; Chung, Jin Young; Chung, Gyung Ho; Kim, Bog Yi; Kuh, Ja Houng [Chunbuk National University Medical School, Chunju (Korea, Republic of)

    1992-07-15

    Three-types of expandable metallic stents were constructed to evaluate the differences between the stents: one, formed in a cylindrical zigzag pattern wth stainless steel wire (Gianturco stent), another, made by coating the Gianturco stent with silicone rubber (Silicone stent), the third, made by coating the Gianturco stent with 24 carat gold (Gold stent) for tissue acceptance. A total of 69 stents (each 23 stents of Gianturco, Silicone, and Gold stents) of 8-12 mm in diameter and 20 mm long were placed into normal abdominal aorta, inferior vena cava and lilac artery of nine adults dogs for 2 weeks to 11 months. It was more difficult to introduce Silicone stent into an introducing sheath than Gianturco or Gold stent due to the thickness of silicone rubber. Four Gianturco stents and three Silicone stents showed migration but Gold stent did not. Luminal narrowing or occlusion was noted in 3 Silicone stents. In 2 Gianturco stents, and in 1 Gold stent. Neointimal proliferation over the stent wires was more rapid and even in Gold stent than Silicone or Gianturco stent. Although further study is needed, Gold stent seems to be better than Gianturco or Silicone stent as an endovascular graft material.

  18. Coronary stent on coronary CT angiography: Assessment with model-based iterative reconstruction technique

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Chae; Kim, Yeo Koon; Chun, Eun Ju; Choi, Sang IL [Dept. of of Radiology, Seoul National University Bundang Hospital, Seongnam (Korea, Republic of)

    2016-05-15

    To assess the performance of model-based iterative reconstruction (MBIR) technique for evaluation of coronary artery stents on coronary CT angiography (CCTA). Twenty-two patients with coronary stent implantation who underwent CCTA were retrospectively enrolled for comparison of image quality between filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR) and MBIR. In each data set, image noise was measured as the standard deviation of the measured attenuation units within circular regions of interest in the ascending aorta (AA) and left main coronary artery (LM). To objectively assess the noise and blooming artifacts in coronary stent, we additionally measured the standard deviation of the measured attenuation and intra-luminal stent diameters of total 35 stents with dedicated software. All image noise measured in the AA (all p < 0.001), LM (p < 0.001, p = 0.001) and coronary stent (all p < 0.001) were significantly lower with MBIR in comparison to those with FBP or ASIR. Intraluminal stent diameter was significantly higher with MBIR, as compared with ASIR or FBP (p < 0.001, p = 0.001). MBIR can reduce image noise and blooming artifact from the stent, leading to better in-stent assessment in patients with coronary artery stent.

  19. Study on the application of big cup membranate stent on restenosis after stenting for carcinoma of esophago cardia

    International Nuclear Information System (INIS)

    Wang Xiuping; Yao Zhongqiang; Liu Jian; Zhang Yan

    2007-01-01

    Objective: To evaluate the clinical value of self-designed big cup membranate stent on restenosis after stenting for carcinoma of esophago-cardia. Methods: 12 cases of restenosis after stenting for carcinoma of esophago-cardia were involved in the study. Self-designed big cup membranate stent made by Nanjing Weichuang Company (the length of the cup was 3.5 cm)was placed into the constricted stent under guidance of fluoroscopy. Clinical effect, restenosis, and complications were observed during followed up. Results: All the 12 cases of big cup membranat stent placement went along smoothly without indigitation of the cup of the stent. Follow-up of 1.5-8 months showed that 2 cases developed severe restenosis on the big cup of the stem, resulting in third grade difficult deglutition. Among them, one occurred 1 month after stenting, caused by hyperplasia of large amount of granulation tissue; another occurred 6 months after stenting, caused by growth of tumor tissue. 3 cases developed mild to moderate restenosis, 2.3-7 months (mean: 4.6 months) after stenting, with result of first grade difficult deglutition. The remaining 7 cases (mean 5.6 months follow-up) did not have difficulty during deglutition. Conclusions: Application of big cup membranate stent on restenosis after stenting for carcinoma of esophago-cardia can effectively prevent the stent from moving downwards and thus lower down the rate of restenosis, and postpone the occurrence of restenosis. (authors)

  20. 4D phase contrast flow imaging for in-stent flow visualization and assessment of stent patency in peripheral vascular stents – A phantom study

    International Nuclear Information System (INIS)

    Bunck, Alexander C.; Jüttner, Alena; Kröger, Jan Robert; Burg, Matthias C.; Kugel, Harald; Niederstadt, Thomas; Tiemann, Klaus; Schnackenburg, Bernhard; Crelier, Gerard R.

    2012-01-01

    Purpose: 4D phase contrast flow imaging is increasingly used to study the hemodynamics in various vascular territories and pathologies. The aim of this study was to assess the feasibility and validity of MRI based 4D phase contrast flow imaging for the evaluation of in-stent blood flow in 17 commonly used peripheral stents. Materials and methods: 17 different peripheral stents were implanted into a MR compatible flow phantom. In-stent visibility, maximal velocity and flow visualization were assessed and estimates of in-stent patency obtained from 4D phase contrast flow data sets were compared to a conventional 3D contrast-enhanced magnetic resonance angiography (CE-MRA) as well as 2D PC flow measurements. Results: In all but 3 of the tested stents time-resolved 3D particle traces could be visualized inside the stent lumen. Quality of 4D flow visualization and CE-MRA images depended on stent type and stent orientation relative to the magnetic field. Compared to the visible lumen area determined by 3D CE-MRA, estimates of lumen patency derived from 4D flow measurements were significantly higher and less dependent on stent type. A higher number of stents could be assessed for in-stent patency by 4D phase contrast flow imaging (n = 14) than by 2D phase contrast flow imaging (n = 10). Conclusions: 4D phase contrast flow imaging in peripheral vascular stents is feasible and appears advantageous over conventional 3D contrast-enhanced MR angiography and 2D phase contrast flow imaging. It allows for in-stent flow visualization and flow quantification with varying quality depending on stent type

  1. 4D phase contrast flow imaging for in-stent flow visualization and assessment of stent patency in peripheral vascular stents--a phantom study.

    Science.gov (United States)

    Bunck, Alexander C; Jüttner, Alena; Kröger, Jan Robert; Burg, Matthias C; Kugel, Harald; Niederstadt, Thomas; Tiemann, Klaus; Schnackenburg, Bernhard; Crelier, Gerard R; Heindel, Walter; Maintz, David

    2012-09-01

    4D phase contrast flow imaging is increasingly used to study the hemodynamics in various vascular territories and pathologies. The aim of this study was to assess the feasibility and validity of MRI based 4D phase contrast flow imaging for the evaluation of in-stent blood flow in 17 commonly used peripheral stents. 17 different peripheral stents were implanted into a MR compatible flow phantom. In-stent visibility, maximal velocity and flow visualization were assessed and estimates of in-stent patency obtained from 4D phase contrast flow data sets were compared to a conventional 3D contrast-enhanced magnetic resonance angiography (CE-MRA) as well as 2D PC flow measurements. In all but 3 of the tested stents time-resolved 3D particle traces could be visualized inside the stent lumen. Quality of 4D flow visualization and CE-MRA images depended on stent type and stent orientation relative to the magnetic field. Compared to the visible lumen area determined by 3D CE-MRA, estimates of lumen patency derived from 4D flow measurements were significantly higher and less dependent on stent type. A higher number of stents could be assessed for in-stent patency by 4D phase contrast flow imaging (n=14) than by 2D phase contrast flow imaging (n=10). 4D phase contrast flow imaging in peripheral vascular stents is feasible and appears advantageous over conventional 3D contrast-enhanced MR angiography and 2D phase contrast flow imaging. It allows for in-stent flow visualization and flow quantification with varying quality depending on stent type. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  2. Stent-over-sponge (SOS): a novel technique complementing endosponge therapy for foregut leaks and perforations.

    Science.gov (United States)

    Valli, Piero V; Mertens, Joachim C; Kröger, Arne; Gubler, Christoph; Gutschow, Christian; Schneider, Paul M; Bauerfeind, Peter

    2018-02-01

     Endoluminal vacuum therapy (EVT) has evolved as a promising option for endoscopic treatment of foregut wall injuries in addition to the classic closure techniques using clips or stents. To improve vacuum force and maintain esophageal passage, we combined endosponge treatment with a partially covered self-expandable metal stent (stent-over-sponge; SOS).  Twelve patients with infected upper gastrointestinal wall defects were treated with the SOS technique.  Indications for SOS were anastomotic leakage after surgery (n = 11) and chronic foregut fistula (n = 1). SOS treatment was used as a first-line treatment in seven patients with a success rate of 71.4 % (5/7) and as a second-line treatment after failed previous EVT treatment in five patients (success rate 80 %; 4/5). Overall, SOS treatment was successful in 75 % of patients (9/12). No severe adverse events occurred. CONCLUSION : SOS is an effective method to treat severely infected foregut wall defects in patients where EVT has failed, and also as a first-line treatment. Comparative prospective studies are needed to confirm our preliminary results. © Georg Thieme Verlag KG Stuttgart · New York.

  3. Intravascular ultrasound assessed incomplete stent apposition and stent fracture in stent thrombosis after bare metal versus drug-eluting stent treatment the Nordic Intravascular Ultrasound Study (NIVUS)

    DEFF Research Database (Denmark)

    Kosonen, Petteri; Vikman, Saila; Jensen, Lisette Okkels

    2012-01-01

    This prospective multicenter registry used intravascular ultrasound (IVUS) in patients with definite stent thrombosis (ST) to compare rates of incomplete stent apposition (ISA), stent fracture and stent expansion in patients treated with drug-eluting (DES) versus bare metal (BMS) stents. ST...... is a rare, but potential life threatening event after coronary stent implantation. The etiology seems to be multifactorial....

  4. Refinement of a thrombectomy technique to treat acute ischemic stroke: Technical note on microcatheter advance during retrieving self expandable stent

    Energy Technology Data Exchange (ETDEWEB)

    Youn, Sung Won; Kim, Ho Kyun [Catholic Univ. of Daegu School of Medicine, Daegu (Korea, Republic of)

    2012-07-15

    Temporary stenting and thrombectomy by use of the Solitaire stent (ev3, Irvine, CA, USA) has shown prompt and successful recanalization of the acutely occluded major cerebral artery. However, even if rarely reported, inadvertent stent detachment may occur as an innate drawback and full deployment of the stent was considered to increase the risk. In our patients, the Solitaire stent did not fully unfold to prevent inadvertent detachment. Before retrieval of the stent, the tip of the microcatheter was advanced forward carefully under fluoroscopic observation until it met the presumed thrombus segment and a subtle sense of resistance was felt in the fingers guiding the stent. After retrieval, complete recanalization was achieved, and the thrombus was trapped between the tip of the microcatheter and the stent strut. We present 2 cases of successful thrombi captures by advancing a microcatheter during Solitaire stent retrieval, and we suggest that advancing the microcatheter can be a useful refinement to the thrombectomy technique for acute ischemic stroke.

  5. Endobronchial Occlusion Stent: A Preliminary Experimental Study

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yo Won; Jeong, Woo Kyoung; Lee, Seoung Hoon; Heo, Jeong Nam; Jeon, Seok Chol [Hanyang University College of Medicine, Seoul (Korea, Republic of); Ko, Gi Young; Song, Ho Young [University of Ulsan College of Medicine, Ulsan (Korea, Republic of)

    2010-04-15

    To evaluate the safety and the technical feasibility of the use of an endobronchial occlusion stent and to get preliminary data for the development of the optimal material required for endobronchial occlusions. A commercialized, self-expandable tracheobronchial stent was modified; one half had a polyurethane cover with an occluded end and the other half was uncovered with a flaring configuration. The occluded end was placed such that it would face the distal lung. Under fluoroscopic guidance, seven stents were placed at the lower lobar bronchus in 6 mini-pigs. The bronchial obstruction was examined immediately after stent placement. Chest radiographs were taken at days 1, 7, 14, and 28 after stent placement and the removed airways from two, two, one, and one mini-pigs sacrificed on corresponding days were examined for the maintenance of bronchial obstruction. Stents were successfully placed and induced the immediate bronchial obstruction in all mini-pigs. Five of seven airways with occlusion stents maintained an obstruction until the mini-pigs were sacrificed. Proximal stent migration occurred in two mini-pigs (29%), and pulmonary consolidations were observed distal to four of the stents (57%). The placement of an endobronchial occlusion stent and the obstruction of targeted bronchi seem to be feasible, but an add-on check valve should be considered to prevent stent migration and obstructive pneumonia

  6. Ureteric catheterization via an ileal conduit: technique and retrieval of a JJ stent.

    Science.gov (United States)

    Wah, T M; Kellett, M J

    2004-11-01

    Retrograde ureteric catheterization of a patient with an ileal conduit is difficult, because guide wires and catheters coil in the conduit. A modified loopogram, using a Foley catheter as a fulcrum through which catheters can be advanced to the ureteric anastomosis, is described. This technique was used to remove a JJ stent, which had been inserted previously across a stricture in one ureter, the stent crossing from one kidney to the other.

  7. Carotid artery stenting: Rationale, technique, and current concepts

    International Nuclear Information System (INIS)

    Yilmaz, Hasan; Pereira, Vitor Mendes; Narata, Ana-Paula; Sztajzel, Roman; Lovblad, Karl-Olof

    2010-01-01

    Carotid stenosis is a major risk factor for stroke. With the aging of the general population and the availability of non-invasive vascular imaging studies, the diagnosis of a carotid plaque is commonly made in medical practice. Asymptomatic and symptomatic carotid stenoses need to be considered separately because their natural history is different. Two large randomized controlled trials (RCTs) showed the effectiveness of carotid endarterectomy (CEA) in preventing ipsilateral ischemic events in patients with symptomatic severe stenosis. The benefit of surgery is much less for moderate stenosis and harmful in patients with stenosis less than 50%. Surgery has a marginal benefit in patients with asymptomatic stenosis. Improvements in medical treatment must be taken into consideration when interpreting the results of these previous trials which compared surgery against medical treatment available at the time the trials were conducted. Carotid artery stenting (CAS) might avoid the risks associated with surgery, including cranial nerve palsy, myocardial infarction, or pulmonary embolism. Therefore and additionally to well-established indications of CAS, this endovascular approach might be a valid alternative particularly in patients at high surgical risk. However, trials of endovascular treatment of carotid stenosis have failed to provide enough evidence to justify routine CAS as an alternative to CEA in patients suitable for surgery. More data from ongoing randomized trials of CEA versus CAS will be soon available. These results will help determining the role of CAS in the management of patients with carotid artery stenosis.

  8. Comparative Computed Flow Dynamic Analysis of Different Optimization Techniques in Left Main Either Provisional or Culotte Stenting.

    Science.gov (United States)

    Rigatelli, Gianluca; Dell'Avvocata, Fabio; Zuin, Marco; Giatti, Sara; Duong, Khanh; Pham, Trung; Tuan, Nguyen Si; Vassiliev, Dobrin; Daggubati, Ramesh; Nguyen, Thach

    2017-12-01

    Provisional and culotte are the most commonly used techniques in left main (LM) stenting. The impact of different post-dilation techniques on fluid dynamic of LM bifurcation has not been yet investigated. The aim of this study is to evaluate, by means of computational fluid dynamic analysis (CFD), the impact of different post-dilation techniques including proximal optimization technique (POT), kissing balloon (KB), POT-Side-POT and POT-KB-POT, 2-steps Kissing (2SK) and Snuggle Kissing balloon (SKB) on flow dynamic profile after LM provisional or culotte stenting. We considered an LM-LCA-LCX bifurcation reconstructed after reviewing 100 consecutive patients (mean age 71.4 ± 9.3 years, 49 males) with LM distal disease. The diameters of LAD and LCX were modelled according to the Finnet's law as following: LM 4.5 mm, LAD 3.5 mm, LCX 2.75 mm, with bifurcation angle set up at 55°. Xience third-generation stent (Abbot Inc., USA) was reconstructed and virtually implanted in provisional/cross-over and culotte fashion. POT, KB, POT-side-POT, POT-KB-POT, 2SK and SKB were virtually applied and analyzed in terms of the wall shear stress (WSS). Analyzing the provisional stenting, the 2SK and KB techniques had a statistically significant lower impact on the WSS at the carina, while POT seemed to obtain a neutral effect. In the wall opposite to the carina, the more physiological profile has been obtained by KB and POT with higher WSS value and smaller surface area of the lower WSS. In culotte stenting, at the carina, POT-KB-POT and 2SK had a very physiological profile; while at the wall opposite to the carina, 2SK and POT-KB-POT decreased significantly the surface area of the lower WSS compared to the other techniques. From the fluid dynamic point of view in LM provisional stenting, POT, 2SK and KB showed a similar beneficial impact on the bifurcation rheology, while in LM culotte stenting, POT-KB-POT and 2SK performed slightly better than the other techniques, probably

  9. Prospective Multicenter Study on the Challenges Inherent to Using Large Cell-Type Stents for Bilateral Stent-in-Stent Placement in Patients with Inoperable Malignant Hilar Biliary Obstruction.

    Science.gov (United States)

    Yang, Min Jae; Kim, Jin Hong; Hwang, Jae Chul; Yoo, Byung Moo; Lee, Sang Hyub; Ryu, Ji Kon; Kim, Yong-Tae; Woo, Sang Myung; Lee, Woo Jin; Jeong, Seok; Lee, Don Haeng

    2018-06-22

    Although endoscopic bilateral stent-in-stent placement is challenging, many recent studies have reported promising outcomes regarding technical success and endoscopic reintervention. This study aimed to evaluate the technical feasibility of stent-in-stent placement using large cell-type stents in patients with inoperable malignant hilar biliary obstruction. Forty-three patients with inoperable malignant hilar biliary obstruction from four academic centers were prospectively enrolled from March 2013 to June 2015. Bilateral stent-in-stent placement using two large cell-type stents was successfully performed in 88.4% of the patients (38/43). In four of the five cases with technical failure, the delivery sheath of the second stent became caught in the hook-cross-type vertex of the large cell of the first stent, and subsequent attempts to pass a guidewire and stent assembly through the mesh failed. Functional success was achieved in all cases with technical success. Stent occlusion occurred in 63.2% of patients (24/38), with a median patient survival of 300 days. The median stent patency was 198 days. The stent patency rate was 82.9%, 63.1%, and 32.1% at 3, 6, and 12 months, respectively. Endoscopic re-intervention was performed in 14 patients, whereas 10 underwent percutaneous drainage. Large cell-type stents for endoscopic bilateral stent-in-stent placement showed acceptable functional success and stent patency when technically successful. However, the technical difficulty associated with the entanglement of the second stent delivery sheath in the hook-cross-type vertex of the first stent may preclude large cell-type stents from being considered as a dedicated standard tool for stent-in-stent placement.

  10. Evaluation of Polyurethane Nasolacrimal Duct Stents: In Vivo Studies in New Zealand Rabbits

    International Nuclear Information System (INIS)

    Wilhelm, K.E.; Grabolle, B.; Urbach, H.; Tolba, R.; Schild, H.; Paulsen, F.

    2006-01-01

    The purpose of this study was to evaluate the radiographic and biological effects of different polyurethane nasolacrimal duct stents in an animal model. Fifteen polyurethane nasolacrimal duct stents (n = 5 mushroom-type stents, n = 5 newly designed S-shaped TearLeader stents without hydrophilic coating, and n = 5 S-shaped TearLeader stents with hydrophilic coating) were implanted in the nasolacrimal ducts of eight unaffected New Zealand rabbits. One nasolacrimal system served as control. Clinical and radiographic follow-up was performed at 1-, 2-, and 4-week intervals, then after a 3-month interval, after which the animals were euthanized. All stents were implanted without major periprocedural complications. The stents proved to be patent by the end of the procedure. During follow-up, all mushroom-type stents were occluded at 4 weeks. None of these stents opened to forced irrigation. Clinically, all rabbits demonstrated severe dacryocystitis. Three out of five TearLeader stents without hydrophilic coating were blocked at 4 weeks; one out of five was open to irrigation. Best results were observed in the stent group with hydrophilic coating. Follow-up dacryocystography demonstrated patent stents in nasolacrimal ducts of all animals after 4 weeks. In only one of five cases, the coated stent became partially occluded after 2 months. These animals were free of clinical symptoms. After 3 months, at least three out of five stents still opened to forced irrigation and only one stent was completely blocked. Dislocation of the stents was not observed. Refinement of the stent surface and stent design improves the results of nasolacrimal duct stenting in this animal model. Implantation of hydrophilic-coated S-shaped stents is highly superior to conventional mushroom-type stents and noncoated stent types. Hydrophilic coating seems to prevent foreign-body reactions, resulting in maximized stent patency

  11. Stenting for curved lesions using a novel curved balloon: Preliminary experimental study.

    Science.gov (United States)

    Tomita, Hideshi; Higaki, Takashi; Kobayashi, Toshiki; Fujii, Takanari; Fujimoto, Kazuto

    2015-08-01

    Stenting may be a compelling approach to dilating curved lesions in congenital heart diseases. However, balloon-expandable stents, which are commonly used for congenital heart diseases, are usually deployed in a straight orientation. In this study, we evaluated the effect of stenting with a novel curved balloon considered to provide better conformability to the curved-angled lesion. In vitro experiments: A Palmaz Genesis(®) stent (Johnson & Johnson, Cordis Co, Bridgewater, NJ, USA) mounted on the Goku(®) curve (Tokai Medical Co. Nagoya, Japan) was dilated in vitro to observe directly the behavior of the stent and balloon assembly during expansion. Animal experiment: A short Express(®) Vascular SD (Boston Scientific Co, Marlborough, MA, USA) stent and a long Express(®) Vascular LD stent (Boston Scientific) mounted on the curved balloon were deployed in the curved vessel of a pig to observe the effect of stenting in vivo. In vitro experiments: Although the stent was dilated in a curved fashion, stent and balloon assembly also rotated conjointly during expansion of its curved portion. In the primary stenting of the short stent, the stent was dilated with rotation of the curved portion. The excised stent conformed to the curved vessel. As the long stent could not be negotiated across the mid-portion with the balloon in expansion when it started curving, the mid-portion of the stent failed to expand fully. Furthermore, the balloon, which became entangled with the stent strut, could not be retrieved even after complete deflation. This novel curved balloon catheter might be used for implantation of the short stent in a curved lesion; however, it should not be used for primary stenting of the long stent. Post-dilation to conform the stent to the angled vessel would be safer than primary stenting irrespective of stent length. Copyright © 2014 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

  12. Direct stent puncture technique for intraluminal stent recanalization in the superficial femoral and popliteal arteries in-stent occlusion: Outcomes from a prospective clinical analysis of diabetics with critical limb ischemia

    Energy Technology Data Exchange (ETDEWEB)

    Palena, Luis Mariano, E-mail: marianopalena@hotmail.com; Manzi, Marco

    2013-07-15

    Purpose: To evaluate the efficacy and safety of “Direct Stent Puncture” technique for intraluminal stent recanalization in the femoro-popliteal segments. Methods and Materials: A cohort of diabetics who had symptomatic in-stent occlusion of the superficial femoral or popliteal arteries underwent endovascular recanalization. After antegrade failure, direct stent puncture technique was performed. The primary end-point was to efficacy assessment, intended as technical success and clinical improvement. The secondary end-point was safety assessment, intended as free of complication rate. Results: Fifty-four patients (37 men; 73.6 ± 8.5 years) underwent direct stent puncture technique, after several unsuccessful antegrade attempts to cross the occluded stent. Technical success for intraluminal stent recanalization was achieved in 53/54 (98.2%) of cases and failed in 1/54 (1.8%). Clinical improvement was obtained in 51/54 (94.4%) of cases, with regression of the clinical symptoms and improvement of the TcPO{sub 2}, from 3 ± 18 mmHg to 43 ± 11 mmHg after 15 days (p < 0.001). Free of complications rate was 92.5%. In 2/54 (3.7%) of cases distal embolization occurred, in 1/54 (1.9%) case a sudden vessel thrombosis was diagnosed after 12 hours and in 1/54 (1.9%) case hematoma at the stent puncture site was observed. Conclusions: Direct Stent Puncture technique is an efficacy and safety option for intraluminal stent recanalization in the femoro-popliteal segment in-stent occlusion.

  13. Plastic Biliary Stent Migration During Multiple Stents Placement and Successful Endoscopic Removal Using Intra-Stent Balloon Inflation Technique: A Case Report and Literature Review.

    Science.gov (United States)

    Calcara, Calcedonio; Broglia, Laura; Comi, Giovanni; Balzarini, Marco

    2016-02-05

    Late migration of a plastic biliary stent after endoscopic placement is a well known complication, but there is little information regarding migration of a plastic stent during multiple stents placement. A white man was hospitalized for severe jaundice due to neoplastic hilar stenosis. Surgical eligibility appeared unclear on admission and endoscopy was carried out, but the first stent migrated proximally at the time of second stent insertion. After failed attempts with various devices, the migrated stent was removed successfully through cannulation with a dilation balloon. The migration of a plastic biliary stent during multiple stents placement is a possible complication. In this context, extraction can be very complicated. In our patient, cannulation of a stent with a dilation balloon was the only effective method.

  14. In-situ investigation of stress conditions during expansion of bare metal stents and PLLA-coated stents using the XRD sin(2)ψ-technique.

    Science.gov (United States)

    Kowalski, Wolfgang; Dammer, Markus; Bakczewitz, Frank; Schmitz, Klaus-Peter; Grabow, Niels; Kessler, Olaf

    2015-09-01

    Drug eluting stents (DES) consist of platform, coating and drug. The platform often is a balloon-expandable bare metal stent made of the CoCr alloy L-605 or stainless steel 316 L. The function of the coating, typically a permanent polymer, is to hold and release the drug, which should improve therapeutic outcome. Before implantation, DES are compressed (crimped) to allow implantation in the human body. During implantation, DES are expanded by balloon inflation. Crimping, as well as expansion, causes high stresses and high strains locally in the DES struts, as well as in the polymer coating. These stresses and strains are important design criteria of DES. Usually, they are calculated numerically by finite element analysis (FEA), but experimental results for validation are hardly available. In this work, the X-ray diffraction (XRD) sin(2)ψ-technique is applied to in-situ determination of stress conditions of bare metal L-605 stents, and Poly-(L-lactide) (PLLA) coated stents. This provides a realistic characterization of the near-surface stress state and a validation option of the numerical FEA. XRD-results from terminal stent struts of the bare metal stent show an increasing compressive load stress in tangential direction with increasing stent expansion. These findings correlate with numerical FEA results. The PLLA-coating also bears increasing compressive load stress during expansion. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Routine short-term ureteral stent in living donor renal transplantation: introduction of a simple stent removal technique without using anesthesia and cystoscope.

    Science.gov (United States)

    Dong, J; Lu, J; Zu, Q; Yang, S; Sun, S; Cai, W; Zhang, L; Zhang, X

    2011-12-01

    We evaluated routine short-time insertion of ureteral stent in living donor renal transplant at a single center. It was easy to remove the stent without cystoscopy and anesthesia. Between October 2007 and July 2010, a single surgeon performed 76 living donor renal transplantations at one institute. All recipients underwent extravesical ureteroneocystostomy with a 2-0 silk suture passed through the venting side hole of the double-J stent into the bladder; a quadruple knot prevented the suture's slippage or distraction from the stent. After removal of the indwelling catheter at 5 days posttransplantation, the 2-0 silk passed with the urinary stream within 72 hours. The double-J stent was removed at 7 to 10 (mean 8.4) days after kidney transplantation by pulling the 2-0 silk out of the urethral orifice without anesthesia or cystoscopy. There was only one case of stenosis, which was resolved by surgery. No patient developed urinary leakage. There were three episodes of urinary tract infection in 70 patients during first 6 months' follow-up. Routine short-term stenting is a safe and effective technique in living donor renal transplantation. Removal of the stent is feasible without cystoscopy or anesthesia. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. A Stent-Retrieving into an Aspiration Catheter with Proximal Balloon (ASAP) Technique: A Technique of Mechanical Thrombectomy.

    Science.gov (United States)

    Goto, Shunsaku; Ohshima, Tomotaka; Ishikawa, Kojiro; Yamamoto, Taiki; Shimato, Shinji; Nishizawa, Toshihisa; Kato, Kyozo

    2018-01-01

    The best technique for the first attempt at mechanical thrombectomy for acute ischemic stroke is a still matter of debate. In this study, we evaluate the efficacy of a stent-retrieving into an aspiration catheter with proximal balloon (ASAP) technique that uses a series of thrombus extraction by withdrawing the stent retriever into the aspiration catheter and continuous aspiration from the aspiration catheter at the first attempt. We performed a retrospective analysis of 42 consecutive patients with acute ischemic stroke caused by occlusions in the anterior circulation who were treated with the ASAP technique at our institution. Preoperative patient characteristic, including age, thrombus location, Alberta Stroke Program Early CT Score, National Institutions of Health Stroke Scale, and time from onset to puncture; postoperative Thrombolysis in Cerebral Infarction score; modified Rankin Scale score after 3 months; time from puncture to recanalization; the number of passes to achieve recanalization; and procedural complications, including intracranial hemorrhage, embolization to new territory, and distal embolization, were assessed. A Thrombolysis in Cerebral Infarction score of 2B or 3 was achieved in 40/42 patients (95.2%). Average time from puncture to the final recanalization was 21.5 minutes. Recanalization was achieved in a single attempt in 31 patients (77.5%). Embolization to new territory was observed in only 2 patients (4.8%); no patient developed distal embolization or intracranial hemorrhage including asymptomatic subarachnoid hemorrhage. Thirty-two patients (76.2%) achieved modified Rankin Scale scores of 0-2 at 3 months postoperatively. Our ASAP technique showed fast recanalization, minimal complications, and good clinical outcomes in this case series. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Pyeloplasty for hydronephrosis: Issues of double J stent versus nephrostomy tube as drainage technique

    Directory of Open Access Journals (Sweden)

    Ravi Kumar Garg

    2015-01-01

    Full Text Available Aims: To compare the efficacy, complications, cost analysis and hospital stay between two methods of drainage of the kidney: double J (DJ stent versus nephrostomy tube following open pyeloplasty for ureteropelvic junction obstruction hydronephrosis. Patients and Methods: This was a prospective randomized study of 20 patients in each group over 14 months. Pre and post-operative (3 months function and drainage were assessed by ethylenedicysteine scan and intravenous urogram. Results: Both groups showed similar good improvement in function and drainage. Nephrostomy group had significantly longer hospital stay (P < 0.001 but incurred less cost. Complications with nephrostomy included tube breakage (n = 1 and urine leak after tube removal (n = 2. DJ stents were associated with stent migration (n = 4, increased frequency of micturition (n = 9, dysuria (n = 4 and urinary tract infection (n = 1. Conclusion: Both methods of drainage did not interfere with improvement after pyeloplasty. Minor complications were more with DJ stent (P = 0.0003. Although overall cost of treatment was more with stents, they reduced length of hospital stay. Optimal length of stent is essential to reduce complications secondary to migration and bladder irritation.

  18. Silicone covered vs. Non- covered endotracheal self expandable metallic stent: An experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Do, Young Soo; Lee, Byung Hee; Kim, Soo Ah; Kim, Kie Hwan; Chin, Soo Yil; Cho, Kyung Ja; Cho, Dae Soon [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

    1994-10-15

    To evaluate pathologic changes of the trachea and the lung after insertion of silicone covered and non covered Gianturco stent in the trachea of dog. Silicone covered(covered) and non covered(bare) Gianturco stent, six in each, were inserted into the tracheal lumen of six consecutive dogs. After 1-10 weeks observation, the dogs were sacrificed and their tracheas and lungs were examined grossly and histopathologically. Serial chest radiographs were performed to evaluate pneumonia and stent migration every 3-5 days. Pneumonia was observed in one of bare stent group and five of covered stent group. Stent migration was noted in three of covered stent group. In bare stent group, the epithelium of the trachea was markedly thickened by hyperplasia and stent was covered by granulation tissue from 6 weeks after stent insertion. Inflammation was focal at contact site between the stent and the trachea. In covered stent group, the epithelium was denuded at multiple areas and there were multifocal squamous metaplasia of the mucosa. Inflammatory reaction of the trachea was diffuse. Inflammatory reaction was more severe and stent migration was more frequent in covered stent group. The use of covered stent in the trachea should be studied further.

  19. [The thermoformable spiral metallic stents in the treatment of localized ureteral stenosis: an alternative to JJ stent? Prospective multicenter study].

    Science.gov (United States)

    Bonniol, R; Meria, P; Safsaf, A; Albouy, B; Sibert, L

    2011-06-01

    Evaluation of the effectiveness and tolerance of thermoformable metallic spiral stents Memokath(®) 051 (Bard, Pnn Medical) in the treatment of localized ureteral stenosis in non-operable patients who have JJ ureteral stents. Prospective, descriptive and multicenter study of patients with ureteral strictures treated with metallic ureteral stents Memokath(®) 051. Assessment criteria (recurrent stenotic, permeability, tolerance) were measured by clinical, biological and radiological examination at 1 month, and then every 3 months. Fifteen stents (average length: 9.15 cm, range 6-15 cm) were implanted in 14 patients (mean age: 55 years, range: 38-72 years) with secondary suspended ureteral stenosis during 2 years in two centers. The median follow-up was 11 months (range 6 to 24 months). Technical difficulty was observed with two patients. Stents are still up in four patients. The stenosis recurred in four patients with spontaneous progression of stenosis but without endoprosthetics tissue invasion. Two and three migration were observed with spontaneous expulsions. Two lower urinary infections and one high occurred, resolved on antibiotic therapy, no inlay or hematuria, no pain (mean VAS score=3/10) or urinary disorders of the lower unit have been identified. Stents Memokath(®) 051 are well tolered and seem to position themselves as an interesting alternative to JJ ureteral stent in some frails patients. The refinement of contraindication should help to improve the stent's efficacity and to reduce the risk of migration and expulsion. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  20. Feasibility and Safety of Transradial Arterial Approach for Simultaneous Right and Left Vertebral Artery Angiographic Studies and Stenting

    International Nuclear Information System (INIS)

    Yip, H.-K.; Youssef, Ali A.; Chang, W.-N.; Lu, C.-H.; Yang, C.-H.; Chen, S.-M.; Wu, C.-J.

    2007-01-01

    Objectives. This study investigated whether the transradial artery (TRA) approach using a 6-French (F) Kimny guiding catheter for right vertebral artery (VA) angiographic study and stenting is safe and effective for patients with significant VA stenosis. Background. The TRA approach is commonly performed worldwide for both diagnostic cardiac catheterization and catheter-based coronary intervention. However, to our knowledge, the safety and feasibility of left and right VA angiographic study and stenting, in the same procedure, using the TRA approach for patients with brain ischemia have not been reported. Methods. The study included 24 consecutive patients (22 male, 2 female; age, 63-78 years). Indications for VA angiographic study and stenting were (1) prior stroke or symptoms related to vertebrobasilar ischemia and (2) an asymptomatic but vertebral angiographic finding of severe stenosis (>70%). A combination of the ipsilateral and retrograde-engagement technique, which involved a looping 6-F Kimny guiding catheter, was utilized for VA angiographic study. For VA stenting, an ipsilateral TRA approach with either a Kimny guiding catheter or a left internal mammary artery guiding catheter was utilized in 22 patients and retrograde-engagement technique in 2 patients. Results. A technically successful procedure was achieved in all patients, including left VA stenting in 15 patients and right VA stenting in 9 patients. The mean time for stenting (from engagement to stent deployment) was 12.7 min. There were no vascular complications or mortality. However, one patient suffered from a transient ischemic attack that resolved within 3 h. Conclusion. We conclude that TRA access for both VA angiographic study and VA stenting is safe and effective, and provides a simple and useful clinical tool for patients unsuited for femoral arterial access

  1. Evaluation of CT virtual intravascular endoscopy in fenestrated stent grafts: a preliminary study

    International Nuclear Information System (INIS)

    Sun, Z.; Allen, Y.; Fitzsimmons, B.; Hartely, D.; Lawrence-Brown, M.

    2007-01-01

    We aim in this study to investigate the potential value of CT virtual intravascular endoscopy in patients diagnosed with abdominal aortic aneurysms undergoing fenestrated stent grafts. Both pre-and post-fenestration (within 3 months of implantation) multislice CT data were collected in eight patients and used for generation of virtual endoscopy images in our preliminary study. Variable fenestrations were deployed in 25 aortic branches with scallop fenestration implanted in six aortic ostia, large fenestration in four aortic ostia and small fenestration in 15 renal ostia, respectively. Measurements of the aortic ostia diameters both pre- and post-fenestration were successfully performed with virtual intravascular endoscopy visualization, and endovascular stents as well as their relationship to the aortic ostia were clearly demonstrated. Our results showed that there was no significant change of diameter of the aortic ostia following fenestrated stem grafts. Endovascular stents were clearly visualized on virtual endoscopy images, and no apparent deformity or malrotation was observed in this small group. Our preliminary study provides new insights into anatomic configuration/dimension of aortic ostia and endovascular stents, and virtual intravascular endoscopy could be a valuable technique to follow-up patients treated with fenestrated stent grafts. (orig.)

  2. Evaluation of CT virtual intravascular endoscopy in fenestrated stent grafts: a preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Z. [Dept. of Imaging and Applied Physics, Curtin Univ. of Tech., Perth, WA (Australia); Allen, Y.; Fitzsimmons, B.; Hartely, D. [Cook R and D, WA (Australia); Lawrence-Brown, M. [Dept. of Public Health, Curtin Univ. of Tech., Perth, WA (Australia)

    2007-06-15

    We aim in this study to investigate the potential value of CT virtual intravascular endoscopy in patients diagnosed with abdominal aortic aneurysms undergoing fenestrated stent grafts. Both pre-and post-fenestration (within 3 months of implantation) multislice CT data were collected in eight patients and used for generation of virtual endoscopy images in our preliminary study. Variable fenestrations were deployed in 25 aortic branches with scallop fenestration implanted in six aortic ostia, large fenestration in four aortic ostia and small fenestration in 15 renal ostia, respectively. Measurements of the aortic ostia diameters both pre- and post-fenestration were successfully performed with virtual intravascular endoscopy visualization, and endovascular stents as well as their relationship to the aortic ostia were clearly demonstrated. Our results showed that there was no significant change of diameter of the aortic ostia following fenestrated stem grafts. Endovascular stents were clearly visualized on virtual endoscopy images, and no apparent deformity or malrotation was observed in this small group. Our preliminary study provides new insights into anatomic configuration/dimension of aortic ostia and endovascular stents, and virtual intravascular endoscopy could be a valuable technique to follow-up patients treated with fenestrated stent grafts. (orig.)

  3. Stent placement with the monorail technique for treatment of mesenteric artery stenosis.

    Science.gov (United States)

    Schaefer, Philipp J; Schaefer, Fritz K W; Hinrichsen, Holger; Jahnke, Thomas; Charalambous, Nikolas; Heller, Martin; Mueller-Huelsbeck, Stefan

    2006-04-01

    To analyze the immediate and midterm success of stenting of mesenteric arteries by a monorail technique in patients with chronic mesenteric ischemia. In this prospective case series, 19 patients (11 male, 8 female; mean age, 62.9 +/- 10.4 y; range, 36-82 y) with 23 symptomatic stenoses of mesenteric arteries were treated with stent placement by a monorail technique in a radiologic intervention center over a period of 4.5 years. Clinical examinations and duplex sonography were used to evaluate the stents' patency and clinical success. Kaplan-Meier graphs were calculated to analyze the patency and freedom-from-symptom rate. Initial technical success rate was 22/23 (96%). Mean follow-up was 17 months (range, 1-58 mo). Primary patency and primary clinical success rates were 82% and 78%, respectively. According to Kaplan-Meier tables, the patency rates were 96%, 87%, 76%, and 61% at 0, 1, 15, and 24 months, respectively, and the freedom-from-symptom rates were 95%, 90%, 72%, and 54% at 0, 1, 24, and 30 months, respectively. No peri-interventional complications occurred. Two patients died of cardiac failure in the hospital within 30 days after intervention; deaths were not related to the intervention. Stent placement by a monorail technique in mesenteric arteries is an effective and safe treatment for symptomatic stenoses in patients with chronic mesenteric ischemia after a mean follow-up of 17 months.

  4. Microvascular stent anastomosis using N-fibroin stents: feasibility, ischemia time, and complications.

    Science.gov (United States)

    Smeets, Ralf; Vorwig, Oliver; Wöltje, Michael; Gaudin, Robert; Luebke, Andreas M; Beck-Broichsitter, Benedicta; Rheinnecker, Michael; Heiland, Max; Grupp, Katharina; Gröbe, Alexander; Hanken, Henning

    2016-05-01

    To evaluate a novel microvascular anastomosis technique using N-fibroin stents. Cylinder stents of 1 mm diameter and 5 mm length were fabricated using N-fibroin from silkworms. In 22 rats, aortas were dissected, and the stent was inserted into the two ends of the aorta and fixed using methylmethacrylate. Stent anastomosis was successful in 21 (96%) rats. The mean ischemia time was 7.4 minutes, significantly shorter than the 15.9 minutes in the control group with conventional sutures (P stent anastomosis cases, and marked host rejection was evident at the stent anastomosis sites. Around the stents, thrombi were frequent (52%). Our study demonstrated the basic feasibility of stent anastomosis using N-fibroin stents and reduced ischemia time. However, thrombus formation, frequent and severe abdominal infections, and heavy host rejection remain critical issues. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. A new technique of deploying dynamic y stent using flexible bronchoscope, video laryngoscope, and laryngeal mask airway.

    Science.gov (United States)

    Obeidat, Shadi; Badin, Shadi; Khawaja, Imran

    2010-04-01

    Dynamic Y stents are used in tracheobronchial obstruction, tracheal stenosis, and tracheomalacia. Placement may be difficult and is usually accomplished using a rigid grasping forceps (under fluoroscopic guidance) or a rigid bronchoscope. We report using a new stent placement technique on an elderly patient with a central tracheobronchial tumor. It included using a flexible bronchoscope, video laryngoscope, and laryngeal mask airway. The new technique we used has the advantages of continuous direct endoscopic visualization during stent advancement and manipulation, and securing the airways with a laryngeal mask airway at the same time. This technique eliminates the need for intraoperative fluoroscopy.

  6. A novel, ring-connected stent versus conventional GI stents: comparative study of physical properties and migration rates in a canine colon obstruction model.

    Science.gov (United States)

    Park, Hong Suk; Choo, In Wook; Seo, Soowon; Hyun, Dongho; Lim, Sooyoun; Kim, Jae J; Hong, Saet-Byul; Min, Byung-Hoon; Do, Young Soo; Choo, Sung Wook; Shin, Sung Wook; Park, Kwang Bo; Cho, Sung Ki

    2015-01-01

    Migration of stents is one of the most common adverse events in covered stent placement in GI tract obstruction. To compare physical property and migration rates in a canine colon obstruction model among a novel stent and conventional stents. Comparative physical test and animal study. Medical device testing laboratory and animal laboratory. Mongrel dogs (N=26). Surgical colon obstruction followed by placement of a novel (n=13) or conventional (n=13) stent. Physical properties, migration, and adverse events. The novel stent showed better flexibility, as in a physical test of longitudinal compressibility and axial force, than did conventional stents, and it withstood the fatigue test for 10 days. In terms of radial force and tensile strength, the novel stent showed the same or better results than conventional stents. In a canine colon obstruction model, the migration rate of a novel stent was significantly lower than that of a conventional stent (2/13, 15.4% vs 8/13, 61.5%; P=.008). Animal study of limited size. The novel, ring-connected stent is more flexible and more resistant to migration than the conventional stents. Copyright © 2015 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

  7. Direct coronary stenting in reducing radiation and radiocontrast consumption

    International Nuclear Information System (INIS)

    Caluk, Jasmin; Osmanovic, Enes; Barakovic, Fahir; Kusljugic, Zumreta; Terzic, Ibrahim; Caluk, Selma; Sofic, Amela

    2010-01-01

    Coronary stenting is the primary means of coronary revascularization. There are two basic techniques of stent implantation: stenting with balloon predilatation of stenosis and stenting without predilatation (direct stenting). Limiting the time that a fluoroscope is activated and by appropriately managing the intensity of the applied radiation, the operator limits radiation in the environment, and this saves the exposure to the patient and all personnel in the room. Nephrotoxicity is one of the most important properties of radiocontrast. The smaller amount of radiocontrast used also provides multiple positive effects, primarily regarding the periprocedural risk for the patients with the reduced renal function. The goal of the study was to compare fluoroscopy time, the amount of radiocontrast, and expenses of material used in direct stenting and in stenting with predilatation. In a prospective study, 70 patients with coronary disease were randomized to direct stenting, or stenting with predilatation. Fluoroscopy time and radiocontrast use were significantly reduced in the directly stented patients in comparison to the patients stented with balloon-predilatation. The study showed a significant reduction of expenses when using a direct stenting method in comparison to stenting with predilatation. If the operator predicts that the procedure can be performed using direct stenting, he is encouraged to do so. Direct stenting is recommended for all percutaneous coronary interventions when appropriate conditions have been met. If direct stenting has been unsuccessful, the procedure can be converted to predilatation

  8. Mechanical behavior of peripheral stents and stent-vessel interaction: A computational study

    Science.gov (United States)

    Dottori, Serena; Flamini, Vittoria; Vairo, Giuseppe

    2016-05-01

    In this paper stents employed to treat peripheral artery disease are analyzed through a three-dimensional finite-element approach, based on a large-strain and large-displacement formulation. Aiming to evaluate the influence of some stent design parameters on stent mechanics and on the biomechanical interaction between stent and arterial wall, quasi-static and dynamic numerical analyses are carried out by referring to computational models of commercially and noncommercially available versions of both braided self-expandable stents and balloon-expandable stents. Addressing isolated device models, opening mechanisms and flexibility of both opened and closed stent configurations are numerically experienced. Moreover, stent deployment into a stenotic peripheral artery and possible postdilatation angioplasty (the latter for the self-expandable device only) are simulated by considering different idealized vessel geometries and accounting for the presence of a stenotic plaque. Proposed results highlight important differences in the mechanical response of the two types of stents, as well as a significant influence of the vessel shape on the stress distributions arising upon the artery-plaque system. Finally, computational results are used to assess both the stent mechanical performance and the effectiveness of the stenting treatment, allowing also to identify possible critical conditions affecting the risk of stent fracture, tissue damage, and/or pathological tissue response.

  9. Directional tip control technique for optimal stent graft alignment in angulated proximal aortic landing zones

    Directory of Open Access Journals (Sweden)

    Toshio Takayama, MD, PhD

    2017-06-01

    Full Text Available Angulated anatomy in the aorta, such as tortuous infrarenal aortic necks or steep aortic arches, is a significant challenge for endovascular aortic repair because it often causes inadequate sealing and fixation, which may lead to treatment failure. We have developed a technique using off-the-shelf equipment to precisely control the deployment of stent grafts in challenging landing zones. The key of this technique is to create a through-and-through wire between two access sites and to use a guiding device over the wire. This technique is best used with stent grafts without nose cones. We present an endovascular aneurysm repair case and a thoracic endovascular aortic repair case with challenging proximal landing zones treated by this technique. In both cases, technical success was attained, and follow-up imaging demonstrated well-aligned stent grafts. Our directional tip control technique is easy and effective. It can be a good technical solution for endovascular aortic treatment in angulated anatomy.

  10. Percutaneous endovascular stent-graft treatment of aortic aneurysms and dissections: new techniques and initial experience

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Do Yun; Choi, Dong Hoon; Kang, Sung Gwon; Lee, Kwang Hoon; Won, Jong Yun [Yonsei University College of Medicine, Seoul (Korea, Republic of); Kang, Sung Gwon [Chosun University College of Medicine, Gwangju (Korea, Republic of); Won, Je Whan [Aju University College of Medicine, Suwon (Korea, Republic of); Song, Ho Young [Ulsan University College of Medicine, Seoul (Korea, Republic of)

    2003-01-01

    To evaluate the feasibility, safety and effectiveness of a newly designed percutaneously implanted separate stent-graft (SSG) for the treatment of aortic aneurysms and dissections. Using a percutaneous technique, SSG placement (in the descending thoracic aorta in 26 cases and infrarenal abdominal aorta in 24) was attempted in 50 patients with aortic aneurysms (n=27) or dissection (n=23). All SSGs were individually constructed using self-expandable nitinol stents and a Dacron graft, and were introduced through a 12 F sheath and expanded to a diameter of 20-34 mm. In all cases, vascular access was through the femoral artery. The clinical status of each patient was monitored, and postoperative CT was performed within one week of the procedure and at 3-6 month intervals afterwards. Endovascular stent-graft deployment was technically successful in 49 of 50 patients (98%). The one failure was due to torsion of the unsupported graft during deployment. Successful exclusion of aneurysms and the primary entry tears of dissections was achieved in all but three patients with aortic dissection. All patients in whom technical success was achieved showed complete thrombosis of the thoracic false lumen or aneurysmal sac, and the overall technique success rate was 92%. In addition, sixteen patients demonstrated complete resolution of the dissected thoracic false lumen (n=9) or aneurysmal sac (n=7). Immediate post-operative complications occurred at the femoral puncture site in one patient with an arteriovenous fistula, and in two, a new saccular aneurysm developed at the distal margin of the stent. No patients died, and there was no instance of paraplegia, stroke, side-branch occlusion or infection during the subsequent mean follow-up period of 9.4 (range, 2 to 26) months. In patients with aortic aneurysm and dissection, treatment with a separate percutaneously inserted stent-graft is technically feasible, safe, and effective.

  11. Transnasal tracheobronchial stenting for malignant airway narrowing under local anesthesia: Our experience of treating three cases using this technique

    International Nuclear Information System (INIS)

    Medhi, Jayanta; Handique, Akash; Goyal, Amit; Lynser, Donbok; Phukan, Pranjal; Sarma, Kalyan; Padmanabhan, Aswin; Saikia, Manuj Kumar; Chutia, Happy

    2016-01-01

    To study the technical feasibility of tracheobronchial stenting via transnasal route under bronchoscopy and fluoroscopic guidance in severe malignant airway strictures using self-expandable nitinol stents. We describe three patients with malignant airway strictures, treated entirely via transnasal route under local anesthesia using bronchoscopic and fluoroscopic guidance. Nasal route allowed convenient access to the airway for the bronchoscope across the stricture and a guidewire was introduced through its working channel. The 18F tracheal stent and the 6F bronchial stent assembly could be easily introduced and deployed under bronchoscopic (reintroduced through the other nostril) and fluoroscopic guidance. We achieved technical success in all the three patients with immediate relief of dyspnea. Transnasal airway stenting with self-expandable nitinol stent using bronchoscopic and fluoroscopic guidance under local anesthesia is a safe and effective method with minimal patient discomfort

  12. Transnasal tracheobronchial stenting for malignant airway narrowing under local anesthesia: Our experience of treating three cases using this technique

    Directory of Open Access Journals (Sweden)

    Jayanta Medhi

    2016-01-01

    Full Text Available Purpose: To study the technical feasibility of tracheobronchial stenting via transnasal route under bronchoscopy and fluoroscopic guidance in severe malignant airway strictures using self-expandable nitinol stents. Materials and Methods: We describe three patients with malignant airway strictures, treated entirely via transnasal route under local anesthesia using bronchoscopic and fluoroscopic guidance. Nasal route allowed convenient access to the airway for the bronchoscope across the stricture and a guidewire was introduced through its working channel. The 18F tracheal stent and the 6F bronchial stent assembly could be easily introduced and deployed under bronchoscopic (reintroduced through the other nostril and fluoroscopic guidance. Results: We achieved technical success in all the three patients with immediate relief of dyspnea. Conclusion: Transnasal airway stenting with self-expandable nitinol stent using bronchoscopic and fluoroscopic guidance under local anesthesia is a safe and effective method with minimal patient discomfort.

  13. Dose perturbation due to the presence of a prostatic urethral stent in patients receiving pelvic radiotherapy: an in vitro study.

    Science.gov (United States)

    Gez, E; Cederbaum, M; Yachia, D; Bar-Deroma, R; Kuten, A

    1997-01-01

    Temporary metallic intraprostatic stent is a new alternative treatment for patients with urinary obstructive syndrome caused by prostate cancer. Definitive radiotherapy is a treatment of choice for localized prostate cancer. This study evaluates in vitro the effect of a urethral intraprostatic metallic stent on the dose absorbed by the surrounding tissue. The study was designed to mimic the conditions under which the prostatic stent is placed in the body during pelvic irradiation. A urethral stent composed of a 50% nickel-50% titanium alloy (Uracoil-InStent) was imbedded in material mimicking normal tissue (bolus) at a simulated body depth of 10 cm. The distribution of the absorbed dose of irradiation was determined by film dosimetry using Kodak X-Omat V film. Irradiation was done in a single field at the isocenter of a 6 MV linear accelerator with a field size of 7 x 7 cm. The degree of film blackening was in direct proportion to the absorbed dose. The measurements showed an increase in dose of up to 20% immediately before the stent and a decrease of up to 18% immediately after the stent. These changes occurred within a range of 1-3 mm from both sides of the stent. In practice, irradiation in prostate cancer is given by two pairs of opposed co-axial fields; a total of four fields (Box Technique). The dose perturbations are partly cancelled in a pair of opposed beams resulting in a net variation of +/- 4%; therefore, the presence of the intraprostatic stent should not influence radiotherapy planning for prostate cancer.

  14. New ischaemic brain lesions on MRI after stenting or endarterectomy for symptomatic carotid stenosis: a substudy of the International Carotid Stenting Study (ICSS)

    NARCIS (Netherlands)

    Bonati, Leo H.; Jongen, Lisa M.; Haller, Sven; Flach, H. Zwenneke; Dobson, Joanna; Nederkoorn, Paul J.; Macdonald, Sumaira; Gaines, Peter A.; Waaijer, Annet; Waajier, Annet; Stierli, Peter; Jäger, H. Rolf; Lyrer, Philippe A.; Kappelle, L. Jaap; Wetzel, Stephan G.; van der Lugt, Aad; Mali, Willem P.; Brown, Martin M.; van der Worp, H. Bart; Engelter, Stefan T.; Koelemaij, M. J. W.; Majoie, C. B. L. M.; Reekers, J. A. A.; Roos, Y. B. W. E. M.; Flach, H. Z.; Hendriks, J. M.; Koudstaal, P. J.; Pattynama, P. M. T.; van Dijk, L. C.; van Sambeek, M. R. H. M.; van der Lugt, A.; van Urk, H.; Verhagen, H. J. M.; de Borst, G. J.; de Kort, G. A. P.; Jongen, L. M.; Kappelle, L. J.; Lo, T. H.; Mali, W. P. Th M.; Moll, F. L.; van der Worp, H. B.; Bonati, L. H.; Engelter, S. T.; Fluri, F.; Haller, S.; Jacob, A. L.; Kirsch, E.; Lyrer, P. A.; Radue, E.-W.; Stierli, P.

    2010-01-01

    BACKGROUND: The International Carotid Stenting Study (ICSS) of stenting and endarterectomy for symptomatic carotid stenosis found a higher incidence of stroke within 30 days of stenting compared with endarterectomy. We aimed to compare the rate of ischaemic brain injury detectable on MRI between the

  15. Percutaneous reconstruction of the innominate bifurcation using the retrograde 'kissing stents' technique

    Energy Technology Data Exchange (ETDEWEB)

    Nagata, Shun-ichi; Kazekawa, Kiyoshi; Matsubara, Shuko [Fukuoka University Chikushi Hospital, Department of Neurosurgery, Chikushino, Fukuoka (Japan); Sugata, Sei [Bironoki Neurosurgical Hospital, Shibushi, Kagoshima (Japan)

    2006-08-15

    Obstructions of the supraaortic vessels are an important cause of morbidity associated with a variety of symptoms. Percutaneous transluminal angioplasty has evolved as an effective and safe treatment modality for occlusive lesions of the supraaortic vessels. However, the endovascular management of an innominate bifurcation has not previously been reported. A 53-year-old female with a history of systematic hypertension, diabetes mellitus and hypercholesterolemia presented with left hemiparesis and dysarthria. Angiography of the innominate artery showed a stenosis of the innominate bifurcation. The lesion was successfully treated using the retrograde kissing stent technique via a brachial approach and an exposed direct carotid approach. The retrograde kissing stent technique for the treatment of a stenosis of the innominate bifurcation was found to be a safe and effective alternative to conventional surgery. (orig.)

  16. Percutaneous reconstruction of the innominate bifurcation using the retrograde 'kissing stents' technique

    International Nuclear Information System (INIS)

    Nagata, Shun-ichi; Kazekawa, Kiyoshi; Matsubara, Shuko; Sugata, Sei

    2006-01-01

    Obstructions of the supraaortic vessels are an important cause of morbidity associated with a variety of symptoms. Percutaneous transluminal angioplasty has evolved as an effective and safe treatment modality for occlusive lesions of the supraaortic vessels. However, the endovascular management of an innominate bifurcation has not previously been reported. A 53-year-old female with a history of systematic hypertension, diabetes mellitus and hypercholesterolemia presented with left hemiparesis and dysarthria. Angiography of the innominate artery showed a stenosis of the innominate bifurcation. The lesion was successfully treated using the retrograde kissing stent technique via a brachial approach and an exposed direct carotid approach. The retrograde kissing stent technique for the treatment of a stenosis of the innominate bifurcation was found to be a safe and effective alternative to conventional surgery. (orig.)

  17. A stent for co-delivering paclitaxel and nitric oxide from abluminal and luminal surfaces: Preparation, surface characterization, and in vitro drug release studies

    Energy Technology Data Exchange (ETDEWEB)

    Gallo, Annemarie; Mani, Gopinath, E-mail: Gopinath.Mani@usd.edu

    2013-08-15

    Most drug-eluting stents currently available are coated with anti-proliferative drugs on both abluminal (toward blood vessel wall) and luminal (toward lumen) surfaces to prevent neointimal hyperplasia. While the abluminal delivery of anti-proliferative drugs is useful for controlling neointimal hyperplasia, the luminal delivery of such drugs impairs or prevents endothelialization which causes late stent thrombosis. This research is focused on developing a bidirectional dual drug-eluting stent to co-deliver an anti-proliferative agent (paclitaxel – PAT) and an endothelial cell promoting agent (nitric oxide – NO) from abluminal and luminal surfaces of the stent, respectively. Phosphonoacetic acid, a polymer-free drug delivery platform, was initially coated on the stents. Then, the PAT and NO donor drugs were co-coated on the abluminal and luminal stent surfaces, respectively. The co-coating of drugs was collectively confirmed by the surface characterization techniques such as Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), 3D optical surface profilometry, and contact angle goniometry. SEM showed that the integrity of the co-coating of drugs was maintained without delamination or cracks formation occurring during the stent expansion experiments. In vitro drug release studies showed that the PAT was released from the abluminal stent surfaces in a biphasic manner, which is an initial burst followed by a slow and sustained release. The NO was burst released from the luminal stent surfaces. Thus, this study demonstrated the co-delivery of PAT and NO from abluminal and luminal stent surfaces, respectively. The stent developed in this study has potential applications in inhibiting neointimal hyperplasia as well as encouraging luminal endothelialization to prevent late stent thrombosis.

  18. A stent for co-delivering paclitaxel and nitric oxide from abluminal and luminal surfaces: Preparation, surface characterization, and in vitro drug release studies

    International Nuclear Information System (INIS)

    Gallo, Annemarie; Mani, Gopinath

    2013-01-01

    Most drug-eluting stents currently available are coated with anti-proliferative drugs on both abluminal (toward blood vessel wall) and luminal (toward lumen) surfaces to prevent neointimal hyperplasia. While the abluminal delivery of anti-proliferative drugs is useful for controlling neointimal hyperplasia, the luminal delivery of such drugs impairs or prevents endothelialization which causes late stent thrombosis. This research is focused on developing a bidirectional dual drug-eluting stent to co-deliver an anti-proliferative agent (paclitaxel – PAT) and an endothelial cell promoting agent (nitric oxide – NO) from abluminal and luminal surfaces of the stent, respectively. Phosphonoacetic acid, a polymer-free drug delivery platform, was initially coated on the stents. Then, the PAT and NO donor drugs were co-coated on the abluminal and luminal stent surfaces, respectively. The co-coating of drugs was collectively confirmed by the surface characterization techniques such as Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), 3D optical surface profilometry, and contact angle goniometry. SEM showed that the integrity of the co-coating of drugs was maintained without delamination or cracks formation occurring during the stent expansion experiments. In vitro drug release studies showed that the PAT was released from the abluminal stent surfaces in a biphasic manner, which is an initial burst followed by a slow and sustained release. The NO was burst released from the luminal stent surfaces. Thus, this study demonstrated the co-delivery of PAT and NO from abluminal and luminal stent surfaces, respectively. The stent developed in this study has potential applications in inhibiting neointimal hyperplasia as well as encouraging luminal endothelialization to prevent late stent thrombosis.

  19. Impact of peri-stent remodeling on restenosis: a volumetric intravascular ultrasound study.

    Science.gov (United States)

    Nakamura, M; Yock, P G; Bonneau, H N; Kitamura, K; Aizawa, T; Tamai, H; Fitzgerald, P J; Honda, Y

    2001-05-01

    Vessel remodeling is an important mechanism of late lumen loss after nonstent coronary interventions. However, its impact on in-stent restenosis has not been systematically investigated. Serial volumetric intravascular ultrasound analyses (poststent and follow-up) were performed in 55 lesions treated with a balloon-expandable stent (ACS MultiLink) using standard stent deployment techniques. The vessel volume (VV), lumen volume (LV), and volume bordered by the stent (SV) were measured using Simpson's method. The volume of plaque and neointima outside the stent (peri-stent volume, PSV) and volume of neointima within the stent (intrastent volume) were also measured. The change of each parameter during the follow-up period (follow-up minus poststent) was calculated and then divided by SV to normalize these values (designated as percent change [%]). As expected, %PSV directly correlated with %VV (Pexterior to a coronary stent occurs to a variable degree after stent implantation. There is a distinct trade-off between positive remodeling and in-stent hyperplasia: in segments in which the degree of peri-stent remodeling is less, intrastent neointimal proliferation is greater and accompanied by more significant late lumen loss.

  20. A computational study of crimping and expansion of bioresorbable polymeric stents

    Science.gov (United States)

    Qiu, T. Y.; Song, M.; Zhao, L. G.

    2017-10-01

    This paper studied the mechanical performance of four bioresorbable PLLA stents, i.e., Absorb, Elixir, Igaki-Tamai and RevaMedical, during crimping and expansion using the finite element method. Abaqus CAE was used to create the geometrical models for the four stents. A tri-folded balloon was created using NX software. For the stents, elastic-plastic behaviour was used, with hardening implemented by considering the increase of yield stress with the plastic strain. The tri-folded balloon was treated as linear elastic. To simulate the crimping of stents, a set of 12 rigid plates were generated around the stents with a radially enforced displacement. During crimping, the stents were compressed from a diameter of 3 mm to 1.2 mm, with the maximum stress developed at both inner and outer sides of the U-bends. During expansion, the stent inner diameter increased to 3 mm at the peak pressure and then recoiled to different final diameters after balloon deflation due to different stent designs. The maximum stress was found again at the U-bends of stents. Diameter change, recoiling effect and radial strength/stiffness were also compared for the four stents to assess the effect of design variation on stent performance. The effect of loading rate on stent deformation was also simulated by considering the time-dependent plastic behaviour of polymeric material.

  1. Randomized multicenter study of multiple plastic stents vs. covered self-expandable metallic stent in the treatment of biliary stricture in chronic pancreatitis.

    Science.gov (United States)

    Haapamäki, Carola; Kylänpää, Leena; Udd, Marianne; Lindström, Outi; Grönroos, Juha; Saarela, Arto; Mustonen, Harri; Halttunen, Jorma

    2015-07-01

    The use of covered self-expandable metallic stents (cSEMS) in benign biliary indications is evolving. The aim of the study was to assess the safety and feasibility of cSEMS compared with multiple plastic stents in the treatment of benign biliary stricture (BBS) caused by chronic pancreatitis. This was a prospective, multicenter, randomized study of 60 patients with BBS caused by chronic pancreatitis. All patients received an initial plastic stent before randomization. At randomization, the stent was replaced either with a single cSEMS or three plastic stents. After 3 months, the position of the cSEMS was checked or another three plastic stents were added. At 6 months after randomization, all stents were removed. Clinical follow-up including abdominal ultrasound and laboratory tests were performed at 6 months and 2 years after stent removal. Two patients dropped out of the cSEMS group before stent removal. In April 2014, the median follow-up was 40 months (range 1 - 66 months). The 2-year, stricture-free success rate was 90 % (95 % confidence interval [CI] 72 % - 97 %) in the plastic stent group and 92 % (95 %CI 70 % - 98 %) in the cSEMS group (P = 0.405). There was one late recurrence in the plastic stent group 50 months after stent removal. Stent migration occurred three times (10 %) in the plastic stent group and twice in the cSEMS group (7 %; P = 1.000). A 6-month treatment with either six 10-Fr plastic stents or with one 10-mm cSEMS produced good long-term relief of biliary stricture caused by chronic pancreatitis.Study registered at ClinicalTrials.gov (NCT01085747). © Georg Thieme Verlag KG Stuttgart · New York.

  2. Wing-shaped plastic stents vs. self-expandable metal stents for palliative drainage of malignant distal biliary obstruction: a randomized multicenter study.

    Science.gov (United States)

    Schmidt, Arthur; Riecken, Bettina; Rische, Susanne; Klinger, Christoph; Jakobs, Ralf; Bechtler, Matthias; Kähler, Georg; Dormann, Arno; Caca, Karel

    2015-05-01

    Previous studies have shown superior patency rates for self-expandable metal stents (SEMS) compared with plastic stents in patients with malignant biliary obstruction. The aim of this study was to compare stent patency, patient survival, and complication rates between a newly designed, wing-shaped, plastic stent and SEMSs in patients with unresectable, malignant, distal, biliary obstruction. A randomized, multicenter trial was conducted at four tertiary care centers in Germany. A total of 37 patients underwent randomization between March 2010 and January 2013. Patients underwent endoscopic retrograde cholangiography with insertion of either a wing-shaped, plastic stent without lumen or an SEMS.  Stent failure occurred in 10/16 patients (62.5 %) in the winged-stent group vs. 4/18 patients (22.2 %) in the SEMS group (P = 0.034). The median time to stent failure was 51 days (range 2 - 92 days) for the winged stent and 80 days (range 28 - 266 days) for the SEMS (P = 0.002). Early stent failure (stent failure was significantly higher in the winged-stent group compared with the SEMS group. A high incidence of early stent failure within 8 weeks was observed in the winged-stent group. Thus, the winged, plastic stent without central lumen may not be appropriate for mid or long term drainage of malignant biliary obstruction. Study registration ClinicalTrials.gov (NCT01063634). © Georg Thieme Verlag KG Stuttgart · New York.

  3. The placement of Y-shaped titanium-nickel memory alloy stent in the carina: a fundamental study in experimental canines

    International Nuclear Information System (INIS)

    Bian Wei; Shen Che

    2010-01-01

    Objective: To investigate the pathological changes of local airway tissue after inserting Yshaped titanium-nickel memory alloy stent in carina, and to evaluate CT three-dimensional reconstruction technique in postoperative and follow-up observation. Methods: Twelve healthy adult canines were enrolled in this study. Based on the information of the carina obtained from CT three-dimensional reconstruction images, the preparation of Y-shape netlike stent was made by knitting method with single Ni-Ti memory alloy wire. The stent was then inserted in canine's carina with the help of a releasing system. After the operation fiberbronchoscopy and CT three-dimensional reconstruction were performed. The animals were sacrificed 12 weeks after the procedure and the bronchus of the stenting segment was removed and sent for histopathologic examination. Results: Technical success was achieved in all canines with the stent right in the carina. The airway remained unobstructed 12 weeks after the procedure. Histopathologic examination revealed that the stent became partial epithelialization. Conclusion: The Y-shaped titanium-nickel memory alloy stent has good histocompatibility and physicochemical stability and no re-stenosis of the airway develops in the follow-up period of three months. The stent-releasing technique is easy and simple. As a non-invasive and convenient exam, CT three-dimensional reconstruction technique is of great value in postoperative follow-up observation. (authors)

  4. Transpedal approach for iliac artery stenting: A pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Zachariah, Jips J., E-mail: jzachariah@chpnet.org [Mount Sinai Beth Israel Hospital, New York, NY (Israel); Ratcliffe, Justin A.; Ruisi, Michael; Puma, Joseph [Mount Sinai Beth Israel Hospital, New York, NY (Israel); Bertrand, Olivier [Quebec Heart and Lung Institute, Quebec (Canada); Kwan, Tak [Mount Sinai Beth Israel Hospital, New York, NY (Israel)

    2016-12-15

    Objective: To demonstrate the safety and feasibility of the transpedal approach as an alternate arterial access site for iliac artery intervention. Background: The common femoral artery is the traditional access site for the endovascular treatment of iliac artery stenoses. However, this approach is associated with complication rates as high as 2%, including retroperitoneal bleeding which carries high patient morbidity and mortality. Furthermore, the standard femoral approach is associated with longer recovery times and longer time to ambulation which are important considerations especially when performing procedures in an ambulatory setting. Methods: Twelve patients were prospectively followed after treatment for symptomatic iliac artery stenosis via transpedal access. Under ultrasound guidance, one of the pedal arteries was visualized and accessed, and stenting of the iliac arteries were performed as per protocol. The patient was monitored immediately post procedure and clinical follow up was performed at one week and one month later. Results: The average age of the patients was 71 years old. 58% were male. Most patients had Rutherford class III symptoms. Successful stent placement was achieved in all 12 patients via transpedal access. No conversion to femoral access was required. No complications immediately post procedure nor at any time period during follow up were noted. Lower extremity arterial duplex at one month showed patent stents and patent pedal access site vessels in all patients. Conclusion: Transpedal arterial access may be a safe and feasible approach for iliac artery stenting. Given the possible benefits of avoiding femoral artery access, larger studies should be conducted directly comparing the different approaches.

  5. Conversion of Percutaneous Cholecystostomy to Endoscopic Gallbladder Stenting by Using the Rendezvous Technique.

    Science.gov (United States)

    Nam, Kwangwoo; Choi, Jun-Ho

    2017-05-01

    We report the successful conversion of percutaneous cholecystostomy (PC) to endoscopic transpapillary gallbladder stenting (ETGS) with insertion of an antegrade guidewire into the duodenum. An 84-year-old man presented with severe acute cholecystitis and septic shock. He had significant comorbidities, and emergent PC was successfully performed. Subsequent ETGS was attempted but unsuccessful owing to difficulties with cystic duct cannulation. However, via the PC tract, the guidewire was passed antegradely into the duodenum, and ETGS with a double-pigtail plastic stent was successfully performed with the rendezvous technique. The PC tube was removed, and no recurrence was reported during the 17-month follow-up period. Conversion of PC to ETGS is a viable option in patients with acute cholecystitis who are not candidates for surgery. Antegrade guidewire insertion via the PC tract may increase the success rate of conversion and decrease the risk of procedure-related complications.

  6. Conversion of Percutaneous Cholecystostomy to Endoscopic Gallbladder Stenting by Using the Rendezvous Technique

    Directory of Open Access Journals (Sweden)

    Kwangwoo Nam

    2017-05-01

    Full Text Available We report the successful conversion of percutaneous cholecystostomy (PC to endoscopic transpapillary gallbladder stenting (ETGS with insertion of an antegrade guidewire into the duodenum. An 84-year-old man presented with severe acute cholecystitis and septic shock. He had significant comorbidities, and emergent PC was successfully performed. Subsequent ETGS was attempted but unsuccessful owing to difficulties with cystic duct cannulation. However, via the PC tract, the guidewire was passed antegradely into the duodenum, and ETGS with a double-pigtail plastic stent was successfully performed with the rendezvous technique. The PC tube was removed, and no recurrence was reported during the 17-month follow-up period. Conversion of PC to ETGS is a viable option in patients with acute cholecystitis who are not candidates for surgery. Antegrade guidewire insertion via the PC tract may increase the success rate of conversion and decrease the risk of procedure-related complications.

  7. Three-Year Major Clinical Outcomes of Angiography-Guided Single Stenting Technique in Non-Complex Left Main Coronary Artery Diseases.

    Science.gov (United States)

    Kim, Yong Hoon; Her, Ae-Young; Rha, Seung-Woon; Choi, Byoung Geol; Shim, Minsuk; Choi, Se Yeon; Byun, Jae Kyeong; Li, Hu; Kim, Woohyeun; Kang, Jun Hyuk; Choi, Jah Yeon; Park, Eun Jin; Park, Sung Hun; Lee, Sunki; Na, Jin Oh; Choi, Cheol Ung; Lim, Hong Euy; Kim, Eung Ju; Park, Chang Gyu; Seo, Hong Seog; Oh, Dong Joo

    2017-10-12

    There is limited long-term comparative clinical outcome data concerning angiography- versus intravascular ultrasound (IVUS)-guided percutaneous coronary intervention (PCI) in non-complex left main coronary artery (LMCA) disease treated with the single stenting technique in the drug-eluting stent (DES) era.The aim of this study was to investigate whether angiography-guided stenting is comparable to IVUS-guided stenting during 3-year clinical follow-up periods in patients with non-complex LM disease treated with the single stenting technique.A total of 196 patients treated with either angiography-guided (n = 74) or IVUS-guided (n = 122) PCI were included. The primary outcome was the occurrence of major adverse cardiac events (MACE) defined as total death, non-fatal myocardial infarction (MI), target lesion revascularization (TLR), target vessel revascularization (TVR), and non-target vessel revascularization (Non-TVR). To adjust for any potential confounders, propensity score (PS) adjusted analysis was performed.During 3-year follow-up, the PS adjusted Cox-proportional hazard ratio (HR) was not significantly different between the two groups for total death, cardiac death, and MI. Also, TLR and the combined rates of TVR and non-TVR were not significantly different. Finally, MACE was not significantly different between the two groups (HR: 0.63, 95% Confidence interval (CI): 0.33-1.17; P = 0.149).Angiography-guided PCI for non-complex LMCA diseases treated with the single stenting technique showed comparable results compared with IVUS-guided PCI in reducing clinical events during 3-year clinical follow-up in the DES era. Although IVUS guided PCI is the ideal strategy, angiography-guided PCI can be an option for LMCA PCI in some selected cases.

  8. Simulative study on dose distribution of 103Pd stent in blood-vessel

    International Nuclear Information System (INIS)

    Yuan Shuyu; Dai Guangfu; Xu Zhiyong; Sun Fuyin; Xu Shuhe; Ma Fengwu

    2003-01-01

    Objective: To evaluate the dose distribution of 103 Pd stent in the blood-vessel. Methods: Simulative study on dose distribution of endovascular 103 Pd stent was conducted with thermoluminescence dosimeter. The vessel wall was substituted by muscle equivalent material in this simulative study. Results: When radioactivity of the study 103 Pd stent was 9.8 MBq the absorbed dose from the stent surface by muscle equivalent material was 9.8 Gy at 17 d (the half-life period of 103 Pd). The radioactivity of 103 Pd stent surface rapidly attenuated over the radial distance. 80% of the radioactivity at the area that was radially 0.4 mm apart from the stent surface was absorbed by the simulative blood-vessel wall. Conclusion: Endovascular 103 Pd stent does not exert significant injury on the surrounding organs or tissues

  9. Safety of hydrophilic guidewires used for side-branch protection during stenting and proximal optimization technique in coronary bifurcation lesions

    Energy Technology Data Exchange (ETDEWEB)

    Chatterjee, Arka [Division of Cardiology, University of Alabama-Birmingham (United States); Brott, Brigitta C. [Division of Cardiology, University of Alabama-Birmingham (United States); Department of Biomedical Engineering, University of Alabama-Birmingham (United States); Foley, Robin [Department of Material Science and Engineering, University of Alabama-Birmingham (United States); Alli, Oluseun; Sasse, Mark; Ahmed, Mustafa; Al Solaiman, Firas; Reddy, Gautam; Ather, Sameer [Division of Cardiology, University of Alabama-Birmingham (United States); Leesar, Massoud A., E-mail: mleesar@uab.edu [Division of Cardiology, University of Alabama-Birmingham (United States)

    2016-10-15

    Background and propose: In coronary bifurcation lesions (CBL), hydrophilic guidewires used for side-branch (SB) protection can be withdrawn from underneath the stent easier than other wires. However, the safety of which has not been investigated. Methods/materials: We performed scanning electron microscopic (SEM) examination of hydrophilic wires – the Whisper and Runthrough wires – used for SB protection during stenting and proximal optimization technique (POT) in 30 patients with CBL. The distal 15 cm of the wire was examined every 1 mm by SEM and 4500 segments were analyzed to investigate for wire fracture, polymer shearing (PS), and its correlations with post-stenting creatine kinase (CK)-MB release. Results: SEM examination showed no evidence for wire fracture. The total area of PS and the largest defect on the wire were significantly larger with the Whisper wire versus the Runthrough wire (0.15 ± 0.04 mm{sup 2} vs. 0.026 ± 0.01 mm{sup 2} and 0.04 ± 0.05 mm{sup 2} vs. 0.01 ± 0.01 mm{sup 2}; P < 0.05, respectively). The total length of PS and the longest defect on the wire were significantly longer with the Whisper wire vs. the Runthrough wire (12.1 ± 14.5 mm vs. 2.7 ± 3.0 mm and 2.9 ± 4.2 mm vs. 1.0 ± 1.2 mm; P < 0.05, respectively), but there were weak correlations between the extents of PS with CK-MB release. Conclusions: Hydrophilic guidewires may be safely used for SB protection during stenting and POT in CBLs. The extent of PS was significantly greater with the Whisper wire than with the Runthrough wire, but its correlation with post-stenting CK-MB release was weak. - Highlights: • There was no wire fracture by jailing hydrophilic wires. • There was no wire entrapment by jailing hydrophilic wires. • There were weak correlations between polymer shearing and creatine kinase-MB levels. • The impact of polymer shearing on myocardial infraction warrants future studies.

  10. Drug-eluting stents studies in mice: Do we need atherosclerosis to study restenosis?

    NARCIS (Netherlands)

    Pires, N.M.M.; Jukema, J.W.; Daemen, M.J.A.P.; Quax, P.H.A.

    2006-01-01

    In 2001, the first human study with drug-eluting stents (DES) was published showing a nearly complete abolition of restenosis by using a sirolimus-eluting stent. This success was very encouraging to test new compounds in combination with the DES platform. Nevertheless, several other anti-restenotic

  11. Symptomatic stent cast.

    LENUS (Irish Health Repository)

    Keohane, John

    2012-02-03

    Biliary stent occlusion is a major complication of endoscopic stent insertion and results in repeat procedures. Various theories as to the etiology have been proposed, the most frequently studied is the attachment of gram negative bacteria within the stent. Several studies have shown prolongation of stent patency with antibiotic prophylaxis. We report the case of stent occlusion from a cast of a previously inserted straight biliary stent; a "stent cast" in an 86-year-old woman with obstructive jaundice. This was retrieved with the lithotrypter and she made an uneventful recovery. This is the first reported case of a biliary stent cast.

  12. Tracheal Self-Expandable Metallic Stents: A Comparative Study of Three Different Stents in a Rabbit Model.

    Science.gov (United States)

    Serrano, Carolina; Lostalé, Fernando; Rodríguez-Panadero, Francisco; Blas, Ignacio de; Laborda, Alicia; de Gregorio, Miguel Angel

    2016-03-01

    The objective of this study was to assess tracheal reactivity after the deployment of different self-expandable metal stents (SEMS). Forty female New Zealand rabbits were divided into four groups. Three groups received three different SEMS: steel (ST), nitinol (NiTi), or nitinol drug-eluting stent (DES); the fourth group was the control group (no stent). Stents were deployed percutaneously under fluoroscopic guidance. Animals were assessed by multi-slice, computed tomography (CT) scans, and tracheas were collected for anatomical pathology (AP) study. Data from CT and AP were statistically analyzed and correlated. The DES group had the longest stenosis (20.51±14.08mm vs. 5.84±12.43 and 6.57±6.54mm in NiTi and ST, respectively, day 30; Pstent. CT was more effective in detecting wall thickening (positive correlation of 68.9%; Pstent, while DES caused significant lesions that may be related to drug dosage. This type of DES stent is therefore not recommended for the treatment of tracheobronchial stenosis. Copyright © 2015 SEPAR. Published by Elsevier Espana. All rights reserved.

  13. Differences in Endothelial Injury After Balloon Angioplasty, Insertion of Balloon-Expanded Stents or Release of Self-Expanding Stents: An Electron Microscopic Experimental Study

    International Nuclear Information System (INIS)

    Harnek, Jan; Zoucas, Evita; Carlemalm, Erik; Cwikiel, Wojciech

    1999-01-01

    Purpose: To evaluate which of six different commonly available stents inserted into an artery without percutaneous transluminal angioplasty (PTA) causes the least endothelial damage. To compare the degree of endothelial injury after insertion of such a stent with injury caused by PTA. Methods: Twelve healthy pigs were used in the experiments. In the first part of the study six different types of stents were inserted into the common iliac arteries. In the second part of the study self-expanding stents with large spaces between the wires were used. PTA was performed in the contralateral iliac artery. The pigs were killed immediately after the procedure and resected specimens examined after fixation, using scanning electron microscopy. Results: All procedures but two were accomplished successfully. More endothelium was preserved after insertion of self-expanding stents with large spaces between the wires, compared with stents with small spaces and balloon-expanded stents. After insertion of self-expanding stents with large spaces, 50.1% ± 16.4% of the endothelium remained intact, compared with only 5.6% ± 7.7% after PTA. The difference was statistically significant (p < 0.001). Conclusion: Self-expanding stents with large spaces between the wires, inserted without PTA, cause less damage to the endothelium than other stents and significantly less damage than PTA

  14. StentBoost Visualization for the Evaluation of Coronary Stent Expansion During Percutaneous Coronary Interventions

    OpenAIRE

    Cura, Fernando; Albertal, Mariano; Candiello, Alfonsina; Nau, Gerardo; Bonvini, Victor; Tricherri, Hernan; Padilla, Lucio T.; Belardi, Jorge A.

    2013-01-01

    Introduction Inadequate stent implantation is associated with stent thrombosis and restenosis. StentBoost can enhance stent visualization and evaluate stent expansion. Currently, there are limited comparison studies between StentBoost and intravascular ultrasound (IVUS). We aimed to test the correlation and agreement between IVUS and StentBoost measurements. Methods From December 2010 to December 2011, 38 patients (54 stents) were analyzed using IVUS and StentBoost. Minimal stent diameter and...

  15. An experimental study on the influence of new spiral stent(Hanaro) on the vascular structures

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jae Hyung; Chung, Jin Wook; Jeong, Yoong Ki; Kook, Myeong Cherl; Seo, Jung Wook [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of); Lim, Myung Kwan [Inha Univ. College of Medicine, Incheon (Korea, Republic of)

    1996-06-01

    The purpose of this study was to evaluate basic experimental data for the clinical application of a self-expandable stainless steel intravascular Hanaro spiral stent. For evaluation of the physical properties of the Hanaro stent, hoop strength, radioopacity, longitudinal flexibility, and foreshortening were measured. Twelve intravascular hanaro spiral stents were placed in the infrarenal abdominal aorta (n=6) and common iliac artery (n=6) in six mongrel dogs. Angiography and light microscopic examination were performed after one, two and eight months of placement of the stents. The stent had good radioopacity and was deployed with minimal foreshortening. hoop strength of a 6 mm-interval bend was found to be superior to that of 8 mm- and 10 mm-bend stent. On angiography the patency rate and thrombosis rate were 100% and 0% in the abdominal aorta and 50% in the common iliac artery, respectively. Minimal corrosion was seen in all stents, and they appeared to be biocompatible. The stent wires were covered with well-developed neointima which after one month had mostly fibroblast and collagen tissue ; the thickness of the neointima increased gradually during a period of eight months. At the end of that period, collagen fibres in the neointima were denser and showed a more paralled configuration than at one month. The Hanaro stent has good physical properties and also has a high patency rate, and good biocompatibilities. The stent may therefore be reliably and safely deployed in the human vascular system.

  16. Useful technique for long-term urinary drainage by inlying ureteral stent. Six-year experience.

    Science.gov (United States)

    Kearney, G P; Mahoney, E M; Brown, H P

    1979-08-01

    Endoscopically placed inlying ureteral stents have proved useful in the conservative management of patients with ureteral obstruction, urinary fistula, and malignancy and have obviated the need for operative intervention. In high-risk symptomatic patients with widespread malignancy, internal urinary diversion offers the opportunity for an improved quality of life without the surgical risk or potential morbidity of supravesical diversion. Potential candidates for this simple, safe, and effective technique include: those with postsurgical obstruction and/or fistula, retroperitoneal fibrosis, metastatic carcinoma, congenital ureteropelvic junction obstruction, as well as those with reversible obstruction from lymphoma and carcinoma of the prostate who are undergoing radiotherapy and/or chemotherapy. The focus of this report is on the technique we have found successful in providing us with stents that fit our individual patients. Readily available fabricated graduated ureteral catheter can be cut and shaped to particular measurements unlike prefabricated catheters. Minimal preparation time is demanded, and there is no need for extensive stocking of various catheter sizes.

  17. Utility of the balloon-overtube-assisted modified over-the-wire stenting technique to treat post-sleeve gastrectomy complications.

    Science.gov (United States)

    Ponte, Ana; Pinho, Rolando; Proença, Luísa; Silva, Joana; Rodrigues, Jaime; Sousa, Mafalda; Silva, João Carlos; Carvalho, João

    2017-06-16

    To describe a modified technique of deployment of stents using the overtube developed for balloon-assisted enteroscopy in post-sleeve gastrectomy (SG) complications. Between January 2010 and December 2015, all patients submitted to an endoscopic stenting procedure to treat a post-SG stenosis or leakage were retrospectively collected. Procedures from patients in which the stent was deployed using the balloon-overtube-assisted modified over-the-wire (OTW) stenting technique were described. The technical success, corresponding to proper placement of the stent in the stomach resulting in exclusion of the SG leak or the stenosis, was evaluated. Complications related to stenting were also reported. Five procedures were included to treat 2 staple line leaks and 3 stenoses. Two types of stents were used, including a fully covered self-expandable metal stent designed for the SG anatomy (Hanarostent, ECBB-30-240-090; M.I. Tech, Co., Ltd, Seoul, South Korea) in 4 procedures and a biodegradable stent (BD stent 019-10A-25/20/25-080, SX-ELLA, Hradec Kralove, Czech Republic) in the remaining procedure. In all cases, an overtube was advanced with the endoscope through the SG to the duodenum. After placement of the guidewire and removal of the endoscope, the stent was easily advanced through the overtube. The overtube was pulled back and the stent was successfully deployed under fluoroscopic guidance. Technical success was achieved in all patients. The adoption of a modified technique of deployment of OTW stents using an overtube may represent an effective option in the approach of SG complications.

  18. Simultaneous stent expansion/balloon deflation technique to salvage failed balloon remodeling.

    Science.gov (United States)

    Ladner, Travis R; He, Lucy; Davis, Brandon J; Froehler, Michael T; Mocco, J

    2016-04-01

    Herniation, with possible embolization, of coils into the parent vessel following aneurysm coiling remains a frequent challenge. For this reason, balloon or stent assisted embolization remains an important technique. Despite the use of balloon remodeling, there are occasions where, on deflation of the balloon, some coils, or even the entire coil mass, may migrate. We report the successful use of a simultaneous adjacent stent deployment bailout technique in order to salvage coil prolapse during balloon remodeling in three patients. Case No 1 was a wide neck left internal carotid artery bifurcation aneurysm, measuring 9 mm×7.9 mm×6 mm with a 5 mm neck. Case No 2 was a complex left superior hypophyseal artery aneurysm, measuring 5.3 mm×4 mm×5 mm with a 2.9 mm neck. Case No 3 was a ruptured right posterior communicating artery aneurysm, measuring 4 mm×4 mm×4.5 mm with a 4 mm neck. This technique successfully returned the prolapsed coil mass into the aneurysm sac in all cases without procedural complications. The closed cell design of the Enterprise VRD (Codman and Shurtleff Inc, Raynham, Massachusetts, USA) makes it ideal for this bailout technique, by allowing the use of an 0.021 inch delivery catheter (necessary for simultaneous access) and by avoiding the possibility of an open cell strut getting caught on the deflated balloon. We hope this technique will prove useful to readers who may find themselves in a similar predicament. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  19. High-Definition Computed Tomography for Coronary Artery Stent Imaging: a Phantom Study

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Wen Jie; Chen, Ke Min; Pang, Li Fang; Zhang, Huang; Pan, Zi Lai [Rui Jin Hospital, Medical School, Shanghai Jiao Tong University, Shangha (China); Guo, Ying; Li, Jian Ying [Beijing Economic and Technology Development Area, Beijing (China)

    2012-01-15

    To assess the performance of a high-definition CT (HDCT) for imaging small caliber coronary stents ({<=} 3 mm) by comparing different scan modes of a conventional 64-row standard-definition CT (SDCT). A cardiac phantom with twelve stents (2.5 mm and 3.0 mm in diameter) was scanned by HDCT and SDCT. The scan modes were retrospective electrocardiography (ECG)-gated helical and prospective ECG-triggered axial with tube voltages of 120 kVp and 100 kVp, respectively. The inner stent diameters (ISD) and the in-stent attenuation value (AVin-stent) and the in-vessel extra-stent attenuation value (AVin-vessel) were measured by two observers. The artificial lumen narrowing (ALN = [ISD - ISDmeasured]/ISD) and artificial attenuation increase between in-stent and in-vessel (AAI = AVin-stent - AVin-vessel) were calculated. All data was analyzed by intraclass correlation and ANOVA-test. The correlation coefficient of ISD, AVin-vessel and AVin-stent between the two observers was good. The ALNs of HDCT were statistically lower than that of SDCT (30 {+-} 5.7% versus 35 {+-} 5.4%, p < 0.05). HDCT had statistically lower AAI values than SDCT (15.7 {+-} 81.4 HU versus 71.4 {+-} 90.5 HU, p < 0.05). The prospective axial dataset demonstrated smaller ALN than the retrospective helical dataset on both HDCT and SDCT (p < 0.05). Additionally, there were no differences in ALN between the 120 kVp and 100 kVp tube voltages on HDCT (p = 0.05). High-definition CT helps improve measurement accuracy for imaging coronary stents compared to SDCT. HDCT with 100 kVp and the prospective ECG-triggered axial technique, with a lower radiation dose than 120 kVp application, may be advantageous in evaluating coronary stents with smaller calibers ({<=} 3 mm).

  20. Insertion of a single double-J stent for bilateral open ureteral reimplantation: introducing a novel technique and assessment of feasibility.

    Science.gov (United States)

    Nabavizadeh, Behnam; Keihani, Sorena; Hosseini Sharifi, Seyed Hossein; Kajbafzadeh, Abdol-Mohammad

    2016-07-01

    To propose a novel technique for bilateral placement of a single double-J stent during bilateral open ureteral reimplantation in order to reduce the intravesical length of stent and potentially minimize the irritative symptoms. A retrospective chart review was performed to find patients who underwent bilateral open ureteral reimplantation. According to the patient's age, an appropriate single double-J stent is used for stenting both ureters after open reimplantation using the Politano-Leadbetter technique. The stent is fixed to the bladder wall with a 4-0 chromic absorbable suture in the midline, superior to the intertrigonal ridge. A non-absorbable suture is also fixed to the stent in the midline as an extraction string. From June 2009 to July 2013, 20 patients underwent bilateral ureteric surgery. Twelve (60 %) were female. Patients' age ranged from 3 months to 2 years. Double-J stents were successfully removed within 2 weeks postoperatively in all patients. This technique might reduce the stent-related symptoms after open bladder surgery for bilateral ureteral surgery. Using this technique will reduce the redundant mass of ureteral stents in bladder and potentially minimize the trigonal irritation and subsequent pain and discomfort.

  1. Experimental Study of Poly-l-Lactic Acid Biodegradable Stents in Normal Canine Bile Ducts

    International Nuclear Information System (INIS)

    Yamamoto, Kiyosei; Yoshioka, Tetsuya; Furuichi, Kinya; Sakaguchi, Hiroshi; Anai, Hiroshi; Tanaka, Toshihiro; Morimoto, Kengo; Uchida, Hideo; Kichikawa, Kimihiko

    2011-01-01

    Purpose: This study was designed to clarify the advantages of biodegradable stents in terms of mucosal reaction and biodegradation after placement. We designed a biodegradable stent and assessed stent degradation and changes in the normal bile ducts of dogs. Methods: The biodegradable stent is a balloon-expandable Z stent consisting of poly-l-lactic acid (PLLA) with a diameter of 6 mm and a length of 15 mm. We assessed four groups of three beagle dogs each at 1, 3, 6, and 9 months of follow-up. After evaluating stent migration by radiography and stent and bile duct patency by cholangiography, the dogs were sacrificed to remove the bile duct together with the stent. The bile duct lumen was examined macroscopically and histologically, and the stent degradation was examined macroscopically and by scanning electron microscopy (SEM). Results: Bile duct obstruction was absent and none of the stents migrated. Macroscopic evaluation showed moderate endothelial proliferation in the bile ducts at the implant sites at 3 and 6 months and a slight change at 9 months. Slight mononuclear cell infiltration was histologically identified at all time points and epithelial hyperplasia that was moderate at 3 months was reduced to slight at 6 and 9 months. Stent degradation was macroscopically evident in all animals at 9 months and was proven by SEM in two dogs at 6 months and in all of them at 9 months. Conclusions: Our results suggest that PLLA bioabsorbable stents seems to be useful for implantation in the biliary system with further investigation.

  2. Percutaneous transcholecystic approach for an experiment of biliary stent placement: an experimental study in dogs

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Tae Seok [Medical School of Gachon, Inchon (Korea, Republic of); Song, Ho Young; Lim, Jin Oh; Ko, Gi Young; Sung, Kyu Bo; Kim, Tae Hyung; Lee, Ho Jung [College of Medicine, Ulsan Univ., Seoul (Korea, Republic of)

    2002-06-01

    To determine, in an experimental study of biliary stent placement, the usefulness and safety of the percutaneous transcholecystic approach and the patency of a newly designed biliary stent. A stent made of 0.15-mm-thick nitinol wire, and 10 mm in diameter and 2 cm in length, was loaded in an introducer with an 8-F outer diameter. The gallbladders of seven mongrel dogs were punctured with a 16-G angiocath needle under sonographic guidance, and cholangiography was performed. After anchoring the anterior wall of the gallbladder to the abdominal wall using a T-fastener, the gallbladder body was punctured again under fluoroscopic guidance. The cystic and common bile ducts were selected using a 0.035-inch guide wire and a cobra catheter, and the stent was placed in the common bile duct. Post-stenting cholangiography was undertaken, and an 8.5-F drainage tube was inserted in the gallbladder. Two dogs were followed-up and sacrificed at 2,4 and 8 weeks after stent placement, respectively, and the other expired 2 days after stent placement. Follow-up cholangiograms were obtained before aninmal was sacrified, and a pathologic examination was performed. Stent placement was technically successful in all cases. One dog expired 2 days after placement because of bile peritonitis due to migration of the drainage tube into the peritoneal cavity, but the other six remained healthy during the follow-up period. Cholangiography performed before the sacrifice of each dog showed that the stents were patent. Pathologic examination revealed the proliferation of granulation tissue at 2 weeks, and complete endothelialization over the stents by granulation tissue at 8 weeks. Percutaneous transcholecystic biliary stent placement appears to be safe, easy and useful. After placement, the stent was patent during the follow-period.

  3. Experimental study of 103Pd stents for preventing the restenosis of biliary duct

    International Nuclear Information System (INIS)

    Gao Qinyi; Shu Qiang; Lu Xiangdong; Li Yaming; He Guijin; Pei Zhuguo; Xu Shuhe

    2004-01-01

    Objective: To explore the feasibility of preventing biliary duct restenosis with the stent treated with 103 Pd and to elucidate the mechanisms of the inhibition of the smooth muscle cell proliferation and the increase of apoptosis. Methods: The experimental dogs were randomly divided into common-stent group and 103 Pd stent group, each of 6 animals. Pathohistology, cell apoptosis, immunohistochemistry for proliferating cell nuclear antigen (PCNA), the expression of gene p53 by in situs hybridization, the test of the peripheral blood and measurement of radiation of tissue around the stent were studied. Results: The utmost intimal thickness of biliary duct in the 103 Pd stent group was found to be obviously less compared to that in common-stent group after 30 d, the percentages of the stenosis of the biliary duct were (54.73 ± 21.64)% and (17.61 ± 14.52)%, respectively, there was a significant difference between two groups (P 103 Pd stent group, and decreased in the common-stent group; the expression of PCNA of biliary smooth muscle cells of 103 Pd group was weaker compared with that in the common-group. Conclusion: 103 Pd stent may inhibit the proliferation of smooth muscle cells and prevent the restenosis of biliary duct. (authors)

  4. Self-made Palmaz stent: an experimental swine model study

    International Nuclear Information System (INIS)

    He Shicheng; Teng Gaojun; Guo Jinhe; Fang Wen

    2000-01-01

    Objective: To investigate the histologic changes and physicochemical stability of self-made Palmaz stent placed in swine arteries. Methods: The self-made Palmaz stent was made of 316L stainless steel wire. Nine stents were respectively placed within internal carotid, renal and iliac arteries of six pigs. Pigs were euthanized at intervals of 0.5, 1 and 3 months respectively and angiography were performed. Immediately followed by light and electro scanning microscopy for the stent zones. Results: All stents were successfully implanted in the target arteries and were patent shown in the angiographic examination immediately after the stent placement. Eight stents (8/9) remained patent at the time before euthanasia. No migration of stent were shown in the follow-up angiography. Light and electron scanning microscopy showed that the surface of the stents was covered by a thin layer of endothelial cells 2 weeks after the procedure and completely covered after 4 weeks. No inflammation occurred. Conclusions: The self-made Palmaz stent has good physicochemical stability and histocompatibility with easy placement, rather long term patency, histopathologic stability and thus the promising for clinical application

  5. An experimental study on expandable endovascular metallic stents in dogs

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ho Young; Kim, Hak Nam [Chonbuk National University College of Medicine, Chonju (Korea, Republic of)

    1990-12-15

    We constructed an expandable endovascular metallic stent in the same way as Giamturco did. Experiments were made to test the ability of these stents to be used in the vessels. A total of 20 stents were passed through a 8.5 French teflon sheath into the normal abdominal aorta. IVC, and iliac artery of four adult dogs for 4 weeks to 12 weeks; 8 stents (10 mm in diameter fully expanded and 20 mm in length) in the abnormal aorta, 7 stents (12 mm/20 mm) in the IVC, and 5 stents (8 mm/20 mm) in the iliac artery. All but two stents showed no migration, and one complete occlusion occurred in right iliac artery of a dog. Histologically, stents wires were covered by neo-intimal proliferation. The side branches of the main vessels remained patent, even stent wires across their orifices. These metallic stents may be used as an endovascular graft material in the nonsurgical treatment of several forms of vascular disease.

  6. Safety of endoscopic removal of self-expandable stents after treatment of benign esophageal diseases.

    Science.gov (United States)

    van Halsema, Emo E; Wong Kee Song, Louis M; Baron, Todd H; Siersema, Peter D; Vleggaar, Frank P; Ginsberg, Gregory G; Shah, Pari M; Fleischer, David E; Ratuapli, Shiva K; Fockens, Paul; Dijkgraaf, Marcel G W; Rando, Giacomo; Repici, Alessandro; van Hooft, Jeanin E

    2013-01-01

    Temporary placement of self-expandable stents has been increasingly used for the management of benign esophageal diseases. To evaluate the safety of endoscopic removal of esophageal self-expandable stents placed for the treatment of benign esophageal diseases. Multicenter retrospective study. Six tertiary care centers in the United States and Europe. A total of 214 patients with benign esophageal diseases undergoing endoscopic stent removal. Endoscopic stent removal. Endoscopic techniques for stent removal, time to stent removal, and adverse events related to stent removal. A total of 214 patients underwent a total of 329 stent extractions. Stents were mainly placed for refractory strictures (49.2%) and fistulae (49.8%). Of the removed stents, 52% were fully covered self-expandable metal stents (FCSEMSs), 28.6% were partially covered self-expandable metal stents (PCSEMSs), and 19.5% were self-expandable plastic stents. A total of 35 (10.6%) procedure-related adverse events were reported, including 7 (2.1%) major adverse events. Multivariate analysis revealed that use of PCSEMSs (P stent removal. Favorable factors for successful stent removal were FCSEMSs (P ≤ .012) and stent migration (P = .010). No significant associations were found for stent indwelling time (P = .145) and stent embedding (P = .194). Retrospective analysis, only tertiary care centers. With an acceptable major adverse event rate of 2.1%, esophageal stent removal in the setting of benign disease was found to be a safe and feasible procedure. FCSEMSs were more successfully removed than self-expandable plastic stents and PCSEMSs. Adverse events caused by stent removal were not time dependent. Copyright © 2013 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

  7. Applying value stream mapping techniques to eliminate non-value-added waste for the procurement of endovascular stents

    International Nuclear Information System (INIS)

    Teichgräber, Ulf K.; Bucourt, Maximilian de

    2012-01-01

    Objectives: To eliminate non-value-adding (NVA) waste for the procurement of endovascular stents in interventional radiology services by applying value stream mapping (VSM). Materials and methods: The Lean manufacturing technique was used to analyze the process of material and information flow currently required to direct endovascular stents from external suppliers to patients. Based on a decision point analysis for the procurement of stents in the hospital, a present state VSM was drawn. After assessment of the current status VSM and progressive elimination of unnecessary NVA waste, a future state VSM was drawn. Results: The current state VSM demonstrated that out of 13 processes for the procurement of stents only 2 processes were value-adding. Out of the NVA processes 5 processes were unnecessary NVA activities, which could be eliminated. The decision point analysis demonstrated that the procurement of stents was mainly a forecast driven push system. The future state VSM applies a pull inventory control system to trigger the movement of a unit after withdrawal by using a consignment stock. Conclusion: VSM is a visualization tool for the supply chain and value stream, based on the Toyota Production System and greatly assists in successfully implementing a Lean system.

  8. A combined technique using a muscular flap and endobronchial stent to repair complex broncho-oesophageal fistulae supported by ECMO.

    Science.gov (United States)

    Baste, Jean-Marc; Haddad, Laura; Philouze, Guillaume

    2018-02-01

    Certain broncho-oesophageal fistulae require surgical repair. Herein, we describe an innovative surgical technique combining intercostal flap and endobronchial stenting. Two patients, each with a with complex broncho-oesophageal fistula 2 years after radio-chemotherapy, were hospitalised for severe respiratory infection and extension of the fistula despite previous endoscopic treatment. The first patient presented with respiratory distress (ARDS). She had emergency surgery under extra corporeal membrane oxygenation: oesophagectomy and reconstruction of the left bronchus by a vascularised intercostal flap. Stenting was performed on day 10, due to persistence of the fistula. At 3 months the bronchus was healed, but the patient died of cerebral bleeding. For the second patient, repair was proposed before severe ARDS with the same surgical and ventilatory strategy and a stent was preventively inserted after surgery. After 3 months, the stent was removed and the left bronchus was healed. Complex post-radiotherapy broncho-oesophageal fistulae should be treated surgically before respiratory complications arise, by combining reconstruction with a vascularised flap and transient stenting.

  9. Applying value stream mapping techniques to eliminate non-value-added waste for the procurement of endovascular stents.

    Science.gov (United States)

    Teichgräber, Ulf K; de Bucourt, Maximilian

    2012-01-01

    OJECTIVES: To eliminate non-value-adding (NVA) waste for the procurement of endovascular stents in interventional radiology services by applying value stream mapping (VSM). The Lean manufacturing technique was used to analyze the process of material and information flow currently required to direct endovascular stents from external suppliers to patients. Based on a decision point analysis for the procurement of stents in the hospital, a present state VSM was drawn. After assessment of the current status VSM and progressive elimination of unnecessary NVA waste, a future state VSM was drawn. The current state VSM demonstrated that out of 13 processes for the procurement of stents only 2 processes were value-adding. Out of the NVA processes 5 processes were unnecessary NVA activities, which could be eliminated. The decision point analysis demonstrated that the procurement of stents was mainly a forecast driven push system. The future state VSM applies a pull inventory control system to trigger the movement of a unit after withdrawal by using a consignment stock. VSM is a visualization tool for the supply chain and value stream, based on the Toyota Production System and greatly assists in successfully implementing a Lean system. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  10. Long-term outcomes after stenting versus endarterectomy for treatment of symptomatic carotid stenosis: the International Carotid Stenting Study (ICSS) randomised trial

    NARCIS (Netherlands)

    Bonati, L.H.; Dobson, J.; Featherstone, R.L.; Ederle, J.; Worp, H.B. van der; Borst, G.J. de; Mali, W.P.; Beard, J.D.; Cleveland, T.; Engelter, S.T.; Lyrer, P.A.; Ford, G.A.; Dorman, P.J.; Brown, M.M.; Leeuw, F.E. de; et al.,

    2015-01-01

    BACKGROUND: Stenting is an alternative to endarterectomy for treatment of carotid artery stenosis, but long-term efficacy is uncertain. We report long-term data from the randomised International Carotid Stenting Study comparison of these treatments. METHODS: Patients with symptomatic carotid

  11. Long-term outcomes after stenting versus endarterectomy for treatment of symptomatic carotid stenosis: the International Carotid Stenting Study (ICSS) randomised trial

    NARCIS (Netherlands)

    Bonati, Leo H.; Dobson, Joanna; Featherstone, Roland L.; Ederle, Jörg; van der Worp, H. Bart; de Borst, Gert J.; Mali, Willem P. Th M.; Beard, Jonathan D.; Cleveland, Trevor; Engelter, Stefan T.; Lyrer, Philippe A.; Ford, Gary A.; Dorman, Paul J.; Brown, Martin M.; Bamford, J.; Beard, J.; Bland, M.; Bradbury, A. W.; Brown, M. M.; Hacke, W.; Halliday, A.; Malik, I.; Mas, J. L.; McGuire, A. J.; Sidhu, P.; Venables, G.; Clifton, A.; Gaines, P.; Collins, R.; Molyneux, A.; Naylor, R.; Warlow, C.; Ferro, J. M.; Thomas, D.; Coward, L.; Dobson, J.; Doig, D.; Ederle, J.; Featherstone, R. F.; Kennedy, F.; Tindall, H.; Turner, E.; McCabe, D. J. H.; Wallis, A.; Brooks, M.; Chambers, B.; Koelemay, M. J. W.; Nederkoorn, P. J.; Reekers, J. A. A.; Roos, Y. B. W. E. M.

    2015-01-01

    Background Stenting is an alternative to endarterectomy for treatment of carotid artery stenosis, but long-term efficacy is uncertain. We report long-term data from the randomised International Carotid Stenting Study comparison of these treatments. Methods Patients with symptomatic carotid stenosis

  12. Biodegradable-Polymer Biolimus-Eluting Stents versus Durable-Polymer Everolimus-Eluting Stents at One-Year Follow-Up: A Registry-Based Cohort Study.

    Science.gov (United States)

    Parsa, Ehsan; Saroukhani, Sepideh; Majlessi, Fereshteh; Poorhosseini, Hamidreza; Lofti-Tokaldany, Masoumeh; Jalali, Arash; Salarifar, Mojtaba; Nematipour, Ebrahim; Alidoosti, Mohammad; Aghajani, Hassan; Amirzadegan, Alireza; Kassaian, Seyed Ebrahim

    2016-04-01

    We compared outcomes of percutaneous coronary intervention patients who received biodegradable-polymer biolimus-eluting stents with those who received durable-polymer everolimus-eluting stents. At Tehran Heart Center, we performed a retrospective analysis of the data from January 2007 through December 2011 on 3,270 consecutive patients with coronary artery disease who underwent percutaneous coronary intervention with the biodegradable-polymer biolimus-eluting stent or the durable-polymer everolimus-eluting stent. We excluded patients with histories of coronary artery bypass grafting or percutaneous coronary intervention, acute ST-segment-elevation myocardial infarction, or the implantation of 2 different stent types. Patients were monitored for 12 months. The primary endpoint was a major adverse cardiac event, defined as a composite of death, nonfatal myocardial infarction, and target-vessel and target-lesion revascularization. Durable-polymer everolimus-eluting stents were implanted in 2,648 (81%) and biodegradable-polymer biolimus-eluting stents in 622 (19%) of the study population. There was no significant difference between the 2 groups (2.7% vs 2.7%; P=0.984) in the incidence of major adverse cardiac events. The cumulative adjusted probability of major adverse cardiac events in the biodegradable-polymer biolimus-eluting stent group did not differ from that of such events in the durable-polymer everolimus-eluting stent group (hazard ratio=0.768; 95% confidence interval, 0.421-1.44; P=0.388). We conclude that in our patients the biodegradable-polymer biolimus-eluting stent was as effective and safe, during the 12-month follow-up period, as was the durable-polymer everolimus-eluting stent.

  13. Flow Velocities After Carotid Artery Stenting: Impact of Stent Design. A Fluid Dynamics Study in a Carotid Artery Model with Laser Doppler Anemometry

    International Nuclear Information System (INIS)

    Greil, Oliver; Kleinschmidt, Thomas; Weiss, Wolfgang; Wolf, Oliver; Heider, Peter; Schaffner, Silvio; Gianotti, Marc; Schmid, Thomas; Liepsch, Dieter; Berger, Hermann

    2005-01-01

    Purpose. To study the influence of a newly developed membrane stent design on flow patterns in a physiologic carotid artery model. Methods. Three different stents were positioned in silicone models of the carotid artery: a stainless steel stent (Wall-stent), a nitinol stent (SelfX), and a nitinol stent with a semipermeable membrane (MembraX). To increase the contact area of the membrane with the vessel wall, another MembranX model was modified at the outflow tract. The membrane consists of a biocompatible silicone-polyurethane copolymer (Elast-Eon) with a pore size of 100 μm. All stents were deployed across the bifurcation and the external carotid artery origin. Flow velocity measurements were performed with laser Doppler anemometry (LDA), using pulsatile flow conditions (Re = 220; flow 0.39 l/min; flow rate ratio ICA:ECA = 70:30) in hemodynamically relevant cross-sections. The hemodynamic changes were analyzed by comparing velocity fluctuations of corresponding flow profiles. Results. The flow rate ratio ICA:ECA shifted significantly from 70/30 to 73.9/26.1 in the MembraX and remained nearly unchanged in the SelfX and Wallstent. There were no changes in the flow patterns at the inflow proximal to the stents. In the stent no relevant changes were found in the SelfX. In the Wallstent the separation zone shifted from the orifice of the ICA to the distal end of the stent. Four millimeters distal to the SelfX and the Wallstent the flow profile returned to normal. In the MembraX an increase in the central slipstreams was found with creation of a flow separation distal to the stent. With a modification of the membrane this flow separation vanished. In the ECA flow disturbances were seen at the inner wall distal to the stent struts in the SelfX and the Wallstent. With the MembraX a calming of flow could be observed in the ECA with a slight loss of flow volume. Conclusions. Stent placement across the carotid artery bifurcation induces alterations of the physiologic flow

  14. The implantation of separating aortic stent-graft into the canine thoracic aorta: an experimental study

    International Nuclear Information System (INIS)

    Xia Jinguo; Shi Haibin; Yang Zhengqiang; Li Chao; Liu Sheng; Zu Qingquan; Li Linsun

    2011-01-01

    Objective: to assess the technical feasibility of implanting separating stent-graft into the canine thoracic aorta and to study its biocompatibility. Methods: Twelve adult dogs were randomly and equally divided into three groups. The right femoral artery was cut open, through which the separating stent-graft was inserted and deployed in the canine thoracic aorta, with the proximal end of the graft being quite close to the origin of the left subclavian artery. the technical feasibility of the deployment process was assessed. Angiography was performed at 4, 8 and 12 weeks after stent-graft placement to evaluate the position and patency of the stent-graft. Then the dogs were sacrificed and the specimens were collected for pathologic study. Both gross and microscopic examinations were made to evaluate the fixation of the stent-graft with the vessel wall, the endothelialization of stent-graft surface and the pathologic changes of the vascular wall. Results: A total of ten separating stent-grafts were successfully deployed in the canine thoracic aorta, no migration or deformation occurred. One dog died of massive bleeding due to the rupture of the right femoral artery which occurred when the delivery system containing the inner bare stent was inserted through the right femoral artery. Death occurred in another dog as a result of the ascending aorta rupture caused by the migration of outer-layer stent-graft. Angiography was conducted at 4, 8 and 12 weeks after stent-graft placement. No migration, deformation, rupture or stenosis of the implanted stent-grafts were observed. The formation of intima on the inner surface of the bare stent appeared at 4 weeks, which became more and more obvious with the time passing, and at 12 weeks complete endothelialization of stent-graft surface was observed. Conclusion: Technically, it is feasible to deploy the separating aortic stent-graft into the canine thoracic aorta. Moreover, the separating aortic stent-graft carries excellent

  15. Temporary self-expanding cardia stents for the treatment of achalasia: an experimental study in dogs

    International Nuclear Information System (INIS)

    Zhu Yueqi; Cheng Yingsheng; Li Minghua; Zhao Jungong; Li Feng; Chen Niwei

    2011-01-01

    Objective: To assess the performance, efficiency and optimal removal time of a newly designed temporary retrievable cardia covered stent (TRC-CS) for the treatment of achalasia in a dog model. Methods: Eighty-four achalasia-like dog models were randomly divided into seven groups of 12, a control group (CG; no stent insertion), a standard stent control group (NSCG, standard esophageal stent) and five treatment groups (TG, TRC-CS). Stents were retrieved at 4 days after insertion in the NSCG and at 4 days (4 d-TG), 2 weeks (2 w-TG), 1 month (1 m-TG), 3 months (3 m-TG), and 6 months (6 m-TG) in the TGs. lower esophageal sphincter pressure (LESP) and a timed barium esophagram were assessed before stent insertion, after stent retrieval, and at 1-week, 1-, 3- and 6-month follow-up. Three dogs in NSCG and 4 d-TG were sacrificed for histological examination at each follow-up to investigate the inflammatory reaction after stent insertion. Results: Stent insertion/removal and the follow-up procedures were well tolerated. At 6-month follow-up, the 2 w-TG and 1 m-TG demonstrated an acceptable stent migration (n=2 in both TGs versus n=4 in NSCG, n=4 in 3 m-TG, and =6 in 6 m-TG), improved LESP compared to after BAC injection (P<0.05), and improved timed barium height (p=0.0144 and 0.0409). Mouse-proliferating cell nuclear antigen (PCNA) and α-smooth muscle actin staining revealed no inflammatory reaction difference between the NSCG and 4d-TG at each follow-up. Conclusion: The TRC-CS was effective in the treatment of achalasia in a dog model. LESP measurements, timed barium esophagram studies suggest an optimal stent retrieval time of between 2 w∼1 m. (authors)

  16. Experimental study of different nickel-titanium memory tracheal stents in dogs

    International Nuclear Information System (INIS)

    Lang Xu; He Nengshu; Fan Hailun

    2009-01-01

    Objective: Since membrane -covered metal tracheal stent was applied successfully to treat the airway stenosis, it has been widely used and obtained satisfactory result during the past years. The purpose of our study was provide theoretical rational for treatment with membrane-covered tracheal stent by using animal experiment. Methods: The nickel- titanium memory stents of 22 mm in diameter and 6 cm in length were deployed in 18 dogs. The dogs were grouped into full- length membrane-covered group (n=6), partial-length membrane-covered group (membrane was covered for 4 cm in the medial part of the stent, n=6), and naked stent group (n=6). After the stent placement dysphagia or dysphonia was monitored daily. Twenty-four weeks later, the dogs were executed. Speiments were taken from the cephalic, medial, and caudal trachea under the stent. HE stain and proliferating cell nuclear antigen (PCNA) were evaluated. Results: After the stent placement, no dyspnea, dysphagia or dysphonia but cough was present in each dog. There was no significant difference in symptom between the three groups. Inflammation reaction, metaplasia from low columnar epithelium to spuamous epithelium, and mild granulation tissue hyperplasia in the underlying mucosa were present in each group. However, fibrosis and tracheal straitness were present only in the non-membrane-covered area, but not in the membrane-covered area. More PCNA expression was observed in the non-membrane -covered area than in the membrane-covered area. Conclusion: Both membrane-covered and non-membrane-covered stents can cause similar symptoms. However, the membrane -covered tracheal stent has good biological compatibility and would not induce tracheal straitness. The non-membrane -covered tracheal stent could induce a severe pathologic reaction and tracheal straitness. (authors)

  17. Bioresorbable polymer coated drug eluting stent: a model study.

    Science.gov (United States)

    Rossi, Filippo; Casalini, Tommaso; Raffa, Edoardo; Masi, Maurizio; Perale, Giuseppe

    2012-07-02

    In drug eluting stent technologies, an increased demand for better control, higher reliability, and enhanced performances of drug delivery systems emerged in the last years and thus offered the opportunity to introduce model-based approaches aimed to overcome the remarkable limits of trial-and-error methods. In this context a mathematical model was studied, based on detailed conservation equations and taking into account the main physical-chemical mechanisms involved in polymeric coating degradation, drug release, and restenosis inhibition. It allowed highlighting the interdependence between factors affecting each of these phenomena and, in particular, the influence of stent design parameters on drug antirestenotic efficacy. Therefore, the here-proposed model is aimed to simulate the diffusional release, for both in vitro and the in vivo conditions: results were verified against various literature data, confirming the reliability of the parameter estimation procedure. The hierarchical structure of this model also allows easily modifying the set of equations describing restenosis evolution to enhance model reliability and taking advantage of the deep understanding of physiological mechanisms governing the different stages of smooth muscle cell growth and proliferation. In addition, thanks to its simplicity and to the very low system requirements and central processing unit (CPU) time, our model allows obtaining immediate views of system behavior.

  18. Expandable metallic stents: An experimental study in the nasolacrimal systems of dogs

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ho Young [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Lee, Jeong Min; Han, Young Min; Hwang, Eui Il; Chung, Gyung Ho; Shon, Myung Hee; Kim, Chong Soo; Choi, Ki Chul [Chonbuk National University Medical School, Chonju(Korea, Republic of)

    1993-11-15

    Balloon dacryocystoplasty has been reported to be a safe, easy and effective nonoperative treatment for nasolacrimal stenosis. The results were not encouraging, however, because of its high failure and recurrence rates. To evaluate the feasibility of using modified Gianturco expandable metallic stents for maintenance of the dilated nasolacrimal system(NLS), 20 stents of 3 mm in diameter and 10 mm long were placed in 20 nasolacrimal ducts of 10 dogs for 1 month to 10 months. It was more difficult to introduce the stents into the proximal portion(A) of the NLS than into the distal portion(B) due to the narrow and bony canal of the A portion. Twenty stents showed no migration in follow-up studies of up to 10 months. One complete occlusion occurred in a stent placed in A portion. Autopsy studies showed stents were covered with epithelium within 2 months after placement. Our experience suggest that the placement of Gianturco self-expandable stents may be a useful method of dilating and maintaining the luminal diameter of the NLS, although care must be taken to select the proper stent size.

  19. Expandable metallic stents: An experimental study in the nasolacrimal systems of dogs

    International Nuclear Information System (INIS)

    Song, Ho Young; Lee, Jeong Min; Han, Young Min; Hwang, Eui Il; Chung, Gyung Ho; Shon, Myung Hee; Kim, Chong Soo; Choi, Ki Chul

    1993-01-01

    Balloon dacryocystoplasty has been reported to be a safe, easy and effective nonoperative treatment for nasolacrimal stenosis. The results were not encouraging, however, because of its high failure and recurrence rates. To evaluate the feasibility of using modified Gianturco expandable metallic stents for maintenance of the dilated nasolacrimal system(NLS), 20 stents of 3 mm in diameter and 10 mm long were placed in 20 nasolacrimal ducts of 10 dogs for 1 month to 10 months. It was more difficult to introduce the stents into the proximal portion(A) of the NLS than into the distal portion(B) due to the narrow and bony canal of the A portion. Twenty stents showed no migration in follow-up studies of up to 10 months. One complete occlusion occurred in a stent placed in A portion. Autopsy studies showed stents were covered with epithelium within 2 months after placement. Our experience suggest that the placement of Gianturco self-expandable stents may be a useful method of dilating and maintaining the luminal diameter of the NLS, although care must be taken to select the proper stent size

  20. Retroperitoneal laparoscopic dismembered pyeloplasty with a novel technique of JJ stenting in children.

    Science.gov (United States)

    Yu, Jianhua; Wu, Zhonghua; Xu, Youming; Li, Zhuo; Wang, Jiansong; Qi, Fan; Chen, Xiang

    2011-09-01

    • To report our experience with retroperitoneal laparoscopic dismembered pyeloplasty for pelvi-ureteric junction (PUJ) obstruction in children. • Between March 2007 and December 2009, 38 children with PUJ obstruction (mean age 8.3 years, range 3-14) underwent retroperitoneal laparoscopic dismembered pyeloplasty. • A ureteric catheter was inserted into the mid-ureter cystoscopically. During pyeloplasty, the proximal end of the ureteric catheter was extracorporeally sutured to the distal end of the JJ stent with silk. • The ureteric catheter was then pulled down and the stent was pulled antegrade into the ureter and bladder. • The approach was retroperitoneal in all patients except one who required open conversion. The overall mean operative time was 162 min (range 145-210 min) and this appeared to decrease with experience. Mean hospital stay was 4 days (range 3-7 days). • Mean follow-up was 20.2 months (range 6-32 months). Satisfactory drainage with decreased hydronephrosis was documented in all patients on ultrasonography and intravenous urography. • Our study shows that retroperitoneal laparoscopic dismembered pyeloplasty is a feasible and effective alternative to open pyeloplasty with a relatively minimal complication rate in children 3 years of age and older, but it should be undertaken by experienced laparoscopic surgeons. © 2011 THE AUTHORS. BJU INTERNATIONAL © 2011 BJU INTERNATIONAL.

  1. Tubular foreign body or stent: safe retrieval or repositioning using the coaxial snare technique

    International Nuclear Information System (INIS)

    Seong, Chang Kyu; Kim, Yong Joo; Chung, Jin Wook; Kim, Seung Hyup; Han, Joon Koo; Kim, Hyun Beom; Park, Jae Hyung

    2002-01-01

    To evaluate the utility and advantages of the coaxial snare technique in the retrieval of tubular foreign bodies. Using the coaxial snare technique, we attempted to retrieve tubular foreign bodies present in seven patients. The bodies were either stents which were malpositioned or had migrated from their correct position in the vascular system (n=2), a fragmented venous introducer sheath (n=1), fragmented drainage catheters in the biliary tree (n=2), or fractured external drainage catheters in the urinary tract (n=2). After passing a guidewire and/or a dilator through the lumina of these foreign bodies, we introduced a loop snare over the guidewire or dilator, thus capturing and retrieving them. In all cases, it was possible to retrieve or reposition the various items, using a minimum-sized introducer sheath or a tract. No folding was involved. In no case were surgical procedures required, and no complications were encountered. The coaxial snare technique, an application of the loop snare technique, is a useful and safe method for the retrieval of tubular foreign bodies, and one which involves minimal injury to the patient

  2. Malignant gastric outlet obstruction managed by endoscopic stenting: a prospective single-centre study

    DEFF Research Database (Denmark)

    Havemann, Maria Cecilie; Adamsen, Sven; Wøjdemann, Morten

    2008-01-01

    -to-treat principle. All patients were offered endoscopic stenting. Oral intake before and after stenting was assessed using the gastric outlet obstruction score system (GOOSS). Various lengths of duodenal Hanaro(R) self-expanding nitinol stents were delivered through a therapeutic endoscope. Outcome criteria were......Objective. Endoscopic stenting for malignant gastric outlet obstruction was chosen as the primary strategy by which to palliate this complication, which is dominated by weight loss and anorexia. Advanced upper gastrointestinal tract cancers present late and life expectancy is limited. Only smaller...... multicentre studies point to endoscopic stenting as superior to surgery in terms of clinical outcome and cost. Material and methods. Forty-five consecutive patients with gastric outlet obstruction as a result of advanced upper GI-tract malignancy were enrolled in accordance with the intention...

  3. Renal PTA stenting

    International Nuclear Information System (INIS)

    Tsetis, D.

    2012-01-01

    Full text: Renal artery stenosis (RAS) is a common condition that may lead to hypertension, progressive renal dysfunction and cardiovascular morbidity. Catheter-based therapy for symptomatic, haemodynamically significant, RAS has become the preferred method of revascularization. Balloon angioplasty has been the traditional treatment of choice for fibromuscular dysplasia, however stents are increasingly used for the treatment of atheromatous lesions; in many cases-such as in ostial lesions-, direct stenting is strongly indicated. Despite the increased use of endovascular therapy for renal artery stenosis, there is still controversy regarding the optimal management and the net benefit of this treatment. Several randomized trials of balloon angioplasty or stenting for renal artery stenosis compared with medical therapy alone have been conducted, however these could not show definite advantage of endovascular therapy. Problems encountered with those trials include enrollment of small number of patients, frequent crossover from medical to interventional therapy compromising the intention-to-treat results, or selection of patients that are not expected to show clear benefit. The Angioplasty and Stenting for Renal Artery Lesions (ASTRAL) is the most important of these trials; however, it,s study design was faulty and therefore did not provide conclusive evidence to answer the question of whether angioplasty and stenting or medical therapy is the best treatment for haemodynamically significant RAS. All expectations are now focused on the Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) trial which was designed to answer the same question, and its methodologies took into consideration the weaknesses of the ASTRAL trial. Regarding stent device itself, it seems that the optimal design is probably a stainless steel, laser cut, open-cells stent mounted on a rapid exchange delivery balloon catheter compatible with 0.014-in and 0.018-in guidewire. As a future

  4. Fully-covered metal stents with endoscopic suturing vs. partially-covered metal stents for benign upper gastrointestinal diseases: a comparative study

    Science.gov (United States)

    Ngamruengphong, Saowanee; Sharaiha, Reem; Sethi, Amrita; Siddiqui, Ali; DiMaio, Christopher J.; Gonzalez, Susana; Rogart, Jason; Jagroop, Sophia; Widmer, Jessica; Im, Jennifer; Hasan, Raza Abbas; Laique, Sobia; Gonda, Tamas; Poneros, John; Desai, Amit; Wong, Katherine; Villgran, Vipin; Brewer Gutierrez, Olaya; Bukhari, Majidah; Chen, Yen-I; Hernaez, Ruben; Hanada, Yuri; Sanaei, Omid; Agarwal, Amol; Kalloo, Anthony N.; Kumbhari, Vivek; Singh, Vikesh; Khashab, Mouen A.

    2018-01-01

    Background and study aims  Self-expandable metallic stents (SEMS) have been increasingly used in benign conditions (e. g. strictures, fistulas, leaks, and perforations). Fully covered SEMS (FSEMS) were introduced to avoid undesirable consequences of partially covered SEMS (PSEMS), but come with higher risk of stent migration. Endoscopic suturing (ES) for stent fixation has been shown to reduce migration of FSEMS. Our aim was to compare the outcomes of FSEMS with ES (FS/ES) versus PSEMS in patients with benign upper gastrointestinal conditions. Patients and methods  We retrospectively identified all patients who underwent stent placement for benign gastrointestinal conditions at seven US tertiary-care centers. Patients were divided into two groups: FSEMS with ES (FS/ES group) and PSEMS (PSEMS group). Clinical outcomes between the two groups were compared. Results  A total of 74 (FS/ES 46, PSEMS 28) patients were included. On multivariable analysis, there was no significant difference in rate of stent migration between FS/ES (43 %) and PSEMS (15 %) (adjusted odds ratio 0.56; 95 % CI 0.15 – 2.00). Clinical success was similar [68 % vs. 64 %; P  = 0.81]. Rate of adverse events (AEs) was higher in PSEMS group [13 (46 %) vs. 10 (21 %); P  = 0.03). Difficult stent removal was higher in the PSEMS group (n = 5;17 %) vs. 0 % in the FS/ES group; P  = 0.005. Conclusions  The proportion of stent migration of FS/ES and PSEMS are similar. Rates of other stent-related AEs were higher in the PSEMS group. PSEMS was associated with tissue ingrowth or overgrowth leading to difficult stent removal, and secondary stricture formation. Thus, FSEMS with ES for stent fixation may be the preferred modality over PSEMS for the treatment of benign upper gastrointestinal conditions. PMID:29404384

  5. Directional Atherectomy in Iliac Stent Failure: Clinical Technique and Histopathologic Correlation

    International Nuclear Information System (INIS)

    Ettles, Duncan F.; MacDonald, Alastair W.; Burgess, Paul A.; Nicholson, Anthony A.; Dyet, John F.

    1998-01-01

    Purpose: To assess the feasibility and efficacy of directional atherectomy in the treatment of iliac stent stenosis or occlusion and to evaluate the histologic composition of excised atherectomy specimens. Methods: Directional atherectomy of six occluded and 10 severely stenosed iliac stents was undertaken in 12 patients at a mean interval of 28 months (range 3-69 months) after stent insertion for occlusive aortoiliac disease. In cases of stent occlusion, atherectomy was preceded by low-dose thrombolysis. In all patients stent clearance with return of femoral pulses was achieved within 24 hr and there were no significant complications. All excised specimens were sent for histologic examination. Results: Eleven patients (92%) remain symptom free with unlimited walking distance at a mean follow-up interval of 11.5 months (range 3-31 months) after treatment. Histologic examination revealed typical myointimal hyperplasia at three excision sites, intimal fibrosis at three sites, atheroma at four sites and organized thrombus at six sites. Conclusion: Atherectomy offers an effective treatment in iliac stent occlusion and restenosis with no significant adverse effects. Debulking of these lesions seems to offer a more logical approach than simple balloon angioplasty. Clinical and duplex follow-up confirms satisfactory outcome within the first year but longer-term results are not yet known. The histologic data obtained demonstrate that stent restenosis and occlusion are likely to be multifactorial, and challenge the assumption that myointimal hyperplasia is the sole cause of iliac stent occlusion

  6. Experimental study with gianturco stent in the trachea of rabbit

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jeong Kook; Kim, Yun Hwan; Suh, Won Hyuck [College of Medicine, Korea University, Seoul (Korea, Republic of)

    1991-09-15

    An expendable stainless steel stent was formulated for use in treatment of tracheobronchial stenosis, tracheomalacia and air way collapse following tracheal reconstruction. The stents were placed throughout an endobronchial tube into the trachea of 20 healthy rabbits. Two different of sizes (10mm, A type and 20mm, B type in diameter and length) and two kinds of shapes (standard, A and B and modified, A' and B' with barbs) were used. Group I were used with A and A' type stents and group II were used with B and B' types. The animals were observed under fluoroscopy and findings were later confirmed at autopsy. With the exception of 2 cases where the stents migrated. 1 case in A subgroup and A' and an inflammatory reaction was noted in each animal. Group II rabbits were almost died within 2-4 weeks after stent placement. In the comparison of the pathohistologic findings between group I and II, the tissue necrosis at the sites of stent placement in trachea is more severe and extensive in group II than that of group I, and also reactive fibroblastic reaction is more severe in group II. So the thickness of the tracheal wall in group II is two or three times thicker than that of group I which seems to be a result of reactive fibrosis. So, A and A' type stent is safer than B and B' type stent in normal rabbit trachea. It is advisable to use stents in diameter under 2 times to tracheal width and the complication of stent placement in trachea may be reduced for appropriate reconstruction of stenotic lesion.

  7. Experimental study with gianturco stent in the trachea of rabbit

    International Nuclear Information System (INIS)

    Park, Jeong Kook; Kim, Yun Hwan; Suh, Won Hyuck

    1991-01-01

    An expendable stainless steel stent was formulated for use in treatment of tracheobronchial stenosis, tracheomalacia and air way collapse following tracheal reconstruction. The stents were placed throughout an endobronchial tube into the trachea of 20 healthy rabbits. Two different of sizes (10mm, A type and 20mm, B type in diameter and length) and two kinds of shapes (standard, A and B and modified, A' and B' with barbs) were used. Group I were used with A and A' type stents and group II were used with B and B' types. The animals were observed under fluoroscopy and findings were later confirmed at autopsy. With the exception of 2 cases where the stents migrated. 1 case in A subgroup and A' and an inflammatory reaction was noted in each animal. Group II rabbits were almost died within 2-4 weeks after stent placement. In the comparison of the pathohistologic findings between group I and II, the tissue necrosis at the sites of stent placement in trachea is more severe and extensive in group II than that of group I, and also reactive fibroblastic reaction is more severe in group II. So the thickness of the tracheal wall in group II is two or three times thicker than that of group I which seems to be a result of reactive fibrosis. So, A and A' type stent is safer than B and B' type stent in normal rabbit trachea. It is advisable to use stents in diameter under 2 times to tracheal width and the complication of stent placement in trachea may be reduced for appropriate reconstruction of stenotic lesion

  8. Experimental study with gianturco stent in the trachea of rabbit

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jeong Kook; Kim, Yun Hwan; Suh, Won Hyuck [College of Medicine, Korea University, Seoul (Korea, Republic of)

    1991-09-15

    An expendable stainless steel stent was formulated for use in treatment of tracheobronchial stenosis, tracheomalacia and air way collapse following tracheal reconstruction. The stents were placed throughout an endobronchial tube into the trachea of 20 healthy rabbits. Two different of sizes (10mm, A type and 20mm, B type in diameter and length) and two kinds of shapes (standard, A and B and modified, A' and B' with barbs) were used. Group I were used with A and A' type stents and group II were used with B and B' types. The animals were observed under fluoroscopy and findings were later confirmed at autopsy. With the exception of 2 cases where the stents migrated. 1 case in A subgroup and A' and an inflammatory reaction was noted in each animal. Group II rabbits were almost died within 2-4 weeks after stent placement. In the comparison of the pathohistologic findings between group I and II, the tissue necrosis at the sites of stent placement in trachea is more severe and extensive in group II than that of group I, and also reactive fibroblastic reaction is more severe in group II. So the thickness of the tracheal wall in group II is two or three times thicker than that of group I which seems to be a result of reactive fibrosis. So, A and A' type stent is safer than B and B' type stent in normal rabbit trachea. It is advisable to use stents in diameter under 2 times to tracheal width and the complication of stent placement in trachea may be reduced for appropriate reconstruction of stenotic lesion.

  9. Initial experience with a new biodegradable airway stent in children: Is this the stent we were waiting for?

    Science.gov (United States)

    Antón-Pacheco, Juan L; Luna, Carmen; García, Enrique; López, María; Morante, Rocío; Tordable, Cristina; Palacios, Alba; de Miguel, Mónica; Benavent, Isabel; Gómez, Andrés

    2016-06-01

    To report our experience with a new type of biodegradable airway stent in the setting of severe tracheobronchial obstruction in children. We conducted a retrospective and prospective (since June 2014) study of pediatric patients with severe airway obstruction treated with biodegradable stents in our institution between 2012 and 2015. The following data were collected: demographics, indication for stenting, bronchoscopic findings, insertion technique complications, clinical outcome, stent related complications, re-stenting, and time of follow-up. Thirteen custom-made polydioxanone stents were placed in four infants (mean age, 4 months) with severe tracheobronchial obstruction: tracheomalacia (two patients), bronchomalacia (1), and diffuse tracheal stenosis (1). All the stents were bronchoscopically inserted uneventfully. Immediate and maintained clinical improvement was observed in every case. No major stent related complications have occurred and only mild or moderate granulation tissue was observed during surveillance bronchoscopy. Two patients required repeated stenting as expected. All the patients are alive and in a good respiratory condition with a follow-up ranging from 5 to 40 months. Biodegradable airway stents seem to be safe, effective, and cause fewer complications than other types of stents. They can be an alternative to the classic metallic or plastic stents for severe tracheal stenosis or malacia in small children. More experience is needed in order to establish the definite clinical criteria for their use in pediatric patients. Pediatr Pulmonol. 2016;51:607-612. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  10. Clinical Outcome After DK Crush Versus Culotte Stenting of Distal Left Main Bifurcation Lesions: The 3-Year Follow-Up Results of the DKCRUSH-III Study.

    Science.gov (United States)

    Chen, Shao-Liang; Xu, Bo; Han, Ya-Ling; Sheiban, Imad; Zhang, Jun-Jie; Ye, Fei; Kwan, Tak W; Paiboon, Chitprapai; Zhou, Yu-Jie; Lv, Shu-Zheng; Dangas, George D; Xu, Ya-Wei; Wen, Shang-Yu; Hong, Lang; Zhang, Rui-Yan; Wang, Hai-Chang; Jiang, Tie-Ming; Wang, Yan; Sansoto, Teguh; Chen, Fang; Yuan, Zu-Yi; Li, Wei-Min; Leon, Martin B

    2015-08-24

    The present study aimed to investigate the difference in major adverse cardiac events (MACE) at 3 years after double-kissing (DK) crush versus culotte stenting for unprotected left main distal bifurcation lesions (LMDBLs). The multicenter and randomized DKCRUSH-III (Comparison of double kissing crush versus culotte stenting for unprotected distal left main bifurcation lesions: results from a multicenter, randomized, prospective study) showed that DK crush stenting was associated with fewer MACE at 1-year follow-up in patients with LMDBLs compared with culotte stenting. Here, we report the 3-year clinical outcome of the DKCRUSH-III study. A total of 419 patients with LMDBLs who were randomly assigned to either the DK crush or culotte group in the DKCRUSH-III study were followed for 3 year. The primary endpoint was the occurrence of a MACE at 3 years. Stent thrombosis (ST) was the safety endpoint. Patients were classified by simple and complex LMDBLs according to the DEFINITION (Definition and Impact of Complex Bifurcation Lesions on Clinical Outcomes After Percutaneous Coronary Intervention Using Drug-Eluting Stents) study criteria. At 3 years, MACE occurred in 49 patients the culotte group and in 17 patients in the DK crush group (cumulative event rates of 23.7% and 8.2%, respectively; p DK crush group (p = 0.007). Complex LMDBLs were associated with a higher rate of MACE (35.3%) at 3 years compared with a rate of 8.1% in patients with simple LMDBLs (p DK] Crush Versus Culotte Stenting for the Treatment of Unprotected Distal Left Main Bifurcation Lesions: DKCRUSH-III, a Multicenter Randomized Study Comparing Double-Stent Techniques; ChiCTR-TRC-11001877). Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  11. Preservation of keratinized mucosa around implants using a prefabricated implant-retained stent: a case-control study

    Science.gov (United States)

    2016-01-01

    Purpose The aim of this study was to clinically assess the impact of a prefabricated implant-retained stent clipped over healing abutments on the preservation of keratinized mucosa around implants after implant surgery, and to compare it with horizontal external mattress sutures. Methods A total of 50 patients were enrolled in this study. In the test group, a prefabricated implant-retained stent was clipped on the healing abutment after implant surgery to replace the keratinized tissue bucco-apically. In the control group, horizontal external mattress sutures were applied instead of using a stent. After the surgical procedure, the width of the buccal keratinized mucosa was measured at the mesial, middle, and distal aspects of the healing abutment. The change in the width of the buccal keratinized mucosa was assessed at 1 and 3 months. Results Healing was uneventful in both groups. The difference of width between baseline and 1 month was −0.26±0.85 mm in the test group, without any statistical significance (P=0.137). Meanwhile, the corresponding difference in the control group was −0.74±0.73 mm and it showed statistical significance (Pprefabricated implant-retained stent was shown to be effective in the preservation of the keratinized mucosa around implants and it was simple and straightforward in comparison to the horizontal external mattress suture technique. PMID:27800215

  12. Management of advanced hilar biliary malignancy with X-shaped stenting technique

    International Nuclear Information System (INIS)

    Hwang, Gyu Hyuk; You, Jin Jong; Ahn, In Oak; Na, Jae Boem; Chung, Sugn Hoon

    2000-01-01

    To report X-shaped stent insertion and its result in the patients with advanced hilar malignancy. X-shaped stents were inserted in six patients with advanced hilar malignancy involving segmental branches of both intrahepatic bile ducts (IHD). The causes were cholangiocarcinomas in five patients and recurrent GB cancer in one. The procedure includes three steps: 1) the insertion of two wires through three IHDs in an X configuration, using a stone basket; 2) balloon dilatation of lesions, and 3) the insertion of two stents in an as X configuration. Stents were inserted after balloon dilatation in five patients, and without balloon dilatation in one. Changes in serum bilirubin levels and procedure-related problems were reviewed. In all patients, serum bilirubin levels gradually decreased, but in two, they increased again. One of these two died of sepsis after 1 month. There was bile leakage through the puncture and bile was extracted from malignant ascites. In the other patient, occlusion of the left stent tip occurred, and additional left PTBD was performed 3 months later. Hemobilia developed in all five patients with balloon dilatation, these all experienced pain during dilatation, but afterwards this disappeared. One stent without pre-balloon dilation showed incomplete self-expansion at the crossing part and supplementary balloon dilatations were performed. In patients with advanced hilar malignancy,X-shaped stent insertion is a new palliation. Problems such as hemobilia, pain, and intraperitoneal bile leakage may, however, occur. (author)

  13. Current Practice of Airway Stenting in the Adult Population in Europe

    DEFF Research Database (Denmark)

    Dutau, Hervé; Breen, David; Bugalho, Antonio

    2018-01-01

    BACKGROUND: Airway stenting (AS) commenced in Europe circa 1987 with the first placement of a dedicated silicone airway stent. Subsequently, over the last 3 decades, AS was spread throughout Europe, using different insertion techniques and different types of stents. OBJECTIVES: This study is an i...

  14. In Vivo Study of Polyurethane-Coated Gianturco-Rosch Biliary Z-Stents

    International Nuclear Information System (INIS)

    Severini, Aldo; Mantero, Sara; Tanzi, Maria Cristina; Cigada, Alberto; Addis, Flaminio; Cozzi, Guido; Salvetti, Monica; Andreola, Salvatore; Motta, Antonella; Regalia, Enrico; Pulvirenti, Andrea; De Pedri, Enrico; Doci, Roberto

    1999-01-01

    Purpose: Prototypes of Gianturco-Rosch Z-stents coated with polycarbonate urethane (PCU) were placed in the biliary tree of pigs, in order to test their biomechanical behavior, stability, and biocompatibility. Methods: The stents were surgically implanted in the common bile duct of three pairs of pigs, which were killed after 1, 3, and 6 months respectively. Explanted livers from pigs of the same race, age, and size were used to provide comparative data. The bile ducts were radiologically and histopathologically examined; the stents were processed and examined by scanning electron microscopy. Results: No complications occurred and the animals showed a normal weight gain. The main bile duct appeared radiologically and macroscopically dilated, but the stents proved to be in place. Histologically, the bile duct epithelium was destroyed, but neither hyperplastic nor inflammatory fibrotic reactions of the wall were evident. Both the metallic structure and the polymeric coating of the stents were intact. A layer of organic material with a maximum thickness of approximately 3 μm was evident on the inner surface of the stents. Conclusion: The present in vivo study demonstrates the biocompatibility, efficacy, and stability of PCU-coated Gianturco-Rosch stents in the biliary environment

  15. MRI assessment of thoracic stent grafts after emergency implantation in multi trauma patients: a feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Rasche, Volker [University Hospital Ulm, Department of Internal Medicine II, Ulm (Germany); University Hospital Ulm, University of Ulm, Department of Internal Medicine II, Ulm (Germany); Oberhuber, Alexander; Orend, Karl-Heinz [University Hospital Ulm, Department of Vascular and Thoracic Surgery, Ulm (Germany); Trumpp, Stephan [University Hospital Ulm, Department of Internal Medicine II, Ulm (Germany); University Hospital Ulm, Department of Vascular and Thoracic Surgery, Ulm (Germany); Bornstedt, Axel; Merkle, Nico; Rottbauer, Wolfgang [University Hospital Ulm, Department of Internal Medicine II, Ulm (Germany); Hoffmann, Martin [University Hospital Ulm, Department of Diagnostic and Interventional Radiology, Ulm (Germany)

    2011-07-15

    To evaluate the feasibility of MRI for static and dynamic assessment of the deployment of thoracic aortic stent grafts after emergency implantation in trauma patients. Twenty patients initially presenting with a rupture of the thoracic aorta were enrolled in this study. All patients underwent thoracic endovascular aortic repair (TEVAR). The deployment of the implanted stent graft was assessed by CTA and MRI, comprising the assessment of the aortic arch with and without contrast agent, and the assessment of the motion of the stent graft over the cardiac cycle. The stent graft geometry and motion over the cardiac cycle were assessable by MRI in all patients. Flow-mediated signal variations in areas of flow acceleration could be well visualised. No statistically significant differences in stent-graft diameters were observed between CT and MRI measurements. MRI appears to be a valuable tool for the assessment of thoracic stent grafts. It shows similar performance in the accurate assessment of stent-graft dimensions to the current gold standard CTA. Its capability of providing additional functional information and the lack of ionising radiation and nephrotoxic contrast agents may make MRI a valuable tool for monitoring patients after TEVAR. (orig.)

  16. Intravascular ultrasound-guided optimized stent deployment. Immediate and 6 months clinical and angiographic results from the Multicenter Ultrasound Stenting in Coronaries Study (MUSIC Study)

    Science.gov (United States)

    de Jaegere, P; Mudra, H; Figulla, H; Almagor, Y; Doucet, S; Penn, I; Colombo, A; Hamm, C; Bartorelli, A; Rothman, M; Nobuyoshi, M; Yamaguchi, T; Voudris, V; DiMario, C; Makovski, S; Hausmann, D; Rowe, S; Rabinovich, S; Sunamura, M; van Es, G A

    1998-08-01

    A study was set up to validate the safety and feasibility of intravascular ultrasound-guided stenting without subsequent anticoagulation, and its impact on the 6 months restenosis rate. The study was designed to be multicentred, prospective, and observational. One hundred and sixty-one patients with stable angina and a de novo coronary artery lesion were enrolled. In four patients, the implantation of a Palmaz-Schatz (with spiral bridge) stent had failed. One of these four patients died 3 days following bypass surgery. In two other patients, intravascular ultrasound assessment was not performed. One hundred and twenty-five of the remaining 155 patients (81%) were treated with aspirin (100 mg x day(-1)), because all three criteria for optimized stent expansion were met. Twenty-two of the remaining 38 patients (25%), in whom at least one criterion was not met were treated with aspirin and acenocoumarol (3 months, INR 2.5-3.5), while 16 patients only received aspirin. Stent thrombosis was documented in two patients (1.3%) for which repeat angioplasty was performed. During the hospital stay, there were no deaths or Q-wave myocardial infarctions. Five patients (3.2%) sustained a non-Q-wave myocardial infarction. During the follow-up period (198+/-38 days, complete for all patients, except one), one patient (0.6%) sustained a Q-wave myocardial infarction, one (0.6%) underwent bypass surgery, and repeat angioplasty was performed in nine patients (5.7%). In two of the nine patients, repeat angioplasty involved another lesion. Therefore, the target lesion revascularization rate during follow-up was 4.5% (seven patients). At quantitative coronary angiography, the minimal lumen diameter (mean+/-SD) increased from 1.12+/-0.34 mm before to 2.89+/-0.35 mm after stenting. Repeat angiography at 6 months was performed in 144 patients (92%). The minimal lumen diameter at follow-up was 2.12+/-0.67 mm. Restenosis (diameter stenosis of 50% or more) was documented in 12 patients or 8

  17. A Fast Placement Technique for Covered Tracheobronchial Stents in Patients with Complicated Esophagorespiratory Fistulas

    International Nuclear Information System (INIS)

    Kishi, Kazushi; Nakao, Taisei; Goto, Hironobu; Kimura, Masashi; Sonomura, Tetsuo; Yamanaka, Noboru; Nanjo, Kishio; Sato, Morio

    2005-01-01

    Purpose. To test an endotracheal placement procedure for malignant esophagorespiratory fistula when endoesophageal placement is inapplicable. Methods. We report on patients with malignant esophagorespiratory fistula to which endoesophageal approaches were complicated with a complete obstruction of the hypopharynx, a collapsible tracheobronchus, or a previously placed endoesophageal stents. Gore-Tex membrane-covered Z-stents were deployed in the trachea using a coaxial introducer system in three patients. A Dumon tube was deployed in the bronchus over the bronchofiberscope in one patient. Results. All fistula were completely sealed by the endotracheal or endobronchial stenting. Symptomatic and clinical improvements were immediate obtained. Conclusion. Endotracheal or endobronchial covered stent placement is thought to be an effective alternative method for sealing esophagorespiratory fistula

  18. Study design and rationale of the 'Balloon-Expandable Cobalt Chromium SCUBA Stent versus Self-Expandable COMPLETE-SE Nitinol Stent for the Atherosclerotic ILIAC Arterial Disease (SENS-ILIAC Trial) Trial': study protocol for a randomized controlled trial.

    Science.gov (United States)

    Choi, Woong Gil; Rha, Seung Woon; Choi, Cheol Ung; Kim, Eung Ju; Oh, Dong Joo; Cho, Yoon Hyung; Park, Sang Ho; Lee, Seung Jin; Hur, Ae Yong; Ko, Young Guk; Park, Sang Min; Kim, Ki Chang; Kim, Joo Han; Kim, Min Woong; Kim, Sang Min; Bae, Jang Ho; Bong, Jung Min; Kang, Won Yu; Seo, Jae Bin; Jung, Woo Yong; Cho, Jang Hyun; Kim, Do Hoi; Ahn, Ji Hoon; Kim, Soo Hyun; Jang, Ji Yong

    2016-06-25

    The self-expandable COMPLETE™ stent (Medtronic) has greater elasticity, allowing it to regain its shape after the compression force reduces, and has higher trackability, thus is easier to maneuver through tortuous vessels, whereas the balloon-expandable SCUBA™ stent (Medtronic) has higher radial stiffness and can afford more accurate placement without geographic miss, which is important in aortoiliac bifurcation lesions. To date, there have been no randomized control trials comparing efficacy and safety between the self-expanding stent and balloon-expandable stent in advanced atherosclerotic iliac artery disease. The purpose of our study is to examine primary patency (efficacy) and incidence of stent fracture and geographic miss (safety) between two different major representative stents, the self-expanding nitinol stent (COMPLETE-SE™) and the balloon-expanding cobalt-chromium stent (SCUBA™), in stenotic or occlusive iliac arterial lesions. This trial is designed as a prospective, randomized, multicenter trial to demonstrate a noninferiority of SCUBA™ stent to COMPLETE-SE™ stent following balloon angioplasty in iliac arterial lesions, and a total of 280 patients will be enrolled. The primary end point of this study is the rate of primary patency in the treated segment at 12 months after intervention as determined by catheter angiography, computed tomography angiography, or duplex ultrasound. The SENS-ILIAC trial will give powerful insight into whether the stent choice according to deployment mechanics would impact stent patency, geographic miss, or stent fracture in patients undergoing stent implantation in iliac artery lesions. National Institutes of Health Clinical Trials Registry (ClinicalTrials.gov identifier: NCT01834495 ), registration date: May 8, 2012.

  19. The SYNERGY biodegradable polymer everolimus eluting coronary stent: Porcine vascular compatibility and polymer safety study.

    Science.gov (United States)

    Wilson, Gregory J; Marks, Angela; Berg, Kimberly J; Eppihimer, Michael; Sushkova, Natalia; Hawley, Steve P; Robertson, Kimberly A; Knapp, David; Pennington, Douglas E; Chen, Yen-Lane; Foss, Aaron; Huibregtse, Barbara; Dawkins, Keith D

    2015-11-15

    SYNERGY is a novel platinum chromium alloy stent that delivers abluminal everolimus from an ultrathin poly-lactide-co-glycide (PLGA) biodegradable polymer. This study evaluated the in vivo degradation of the polymer coating, everolimus release time course, and vascular compatibility of the SYNERGY stent. SYNERGY stents were implanted in arteries of domestic swine. Devices were explanted at predetermined time points (up to 120 days) and the extent of PLGA coating or everolimus remaining on the stents was quantified. Everolimus levels in the arterial tissue were also evaluated. A pathological analysis on coronary arteries of single and overlapping stents was performed at time points between 5 and 270 days. PLGA bioabsorption began immediately after implantation, and drug release was essentially complete by 90 days; PLGA absorption was substantially complete by 120 days (>90% of polymer was absorbed) leaving a bare metal SYNERGY stent. Vascular response was similar among SYNERGY and control stents (bare metal, polymer-only, and 3× polymer-only). Mild increases in para-strut fibrin were seen for SYNERGY at an early time point with no significant differences in all other morphological and morphometric parameters through 270 days or endothelial function (eNOS immunostaining) at 90 or 180 days. Inflammation was predominantly minimal to mild for all device types. In a swine model, everolimus was released by 90 days and PLGA bioabsorption was complete shortly thereafter. The SYNERGY stent and its biodegradable polymer, even at a 3× safety margin, demonstrated vascular compatibility similar to bare metal stent controls. © 2015 Wiley Periodicals, Inc.

  20. A new technique for end-to-end ureterostomy in the rat, using an indwelling reabsorbable stent.

    Science.gov (United States)

    Carmignani, G; Farina, F P; De Stefani, S; Maffezzini, M

    1983-01-01

    The restoration of the continuity of the urinary tract represents one of the major problems in rat renal transplantation. End-to-end ureterostomy is the most physiologically effective technique; however, it involves noteworthy technical difficulties because of the extremely thin caliber of the ureter in the rat and the high incidence of postoperative hydronephrosis. We describe a new technique for end-to-end ureterostomy in the rat, where the use of an absorbable ureteral stent is recommended. A 5-0 plain catgut thread is used as a stent. The anastomosis is performed under an operating microscope at X 25-40 magnification with interrupted sutures of 11-0 Vicryl. The use of the indwelling stent facilitates the performance of the anastomosis and yields optimal results. The macroscopical, radiological, and histological controls in a group of rats operated on with this technique showed a very high percentage of success with no complications, a result undoubtedly superior to that obtained with conventional methods.

  1. The effect of stent coating on stent deliverability: direct randomised comparison of drug eluting and bare metal stents using the same stent platform.

    Science.gov (United States)

    Siminiak, Tomasz; Link, Rafał; Wołoszyn, Maciej; Kałmucki, Piotr; Baszko, Artur

    2012-01-01

    There is certain experimental and clinical evidence indicating that the covering of bare metal stents (BMS) with drug eluting polymers to produce drug eluting stents (DES) results in increased stent stiffness and modifies the mechanical properties of the stent platform. In addition, it has been speculated that the mechanical performance of DES, compared to BMS, may be related to the type of polymer used to cover stents. We aimed at evaluating the deliverability of DES with a lactate based biodegradable polymer and BMS in patients with stable coronary artery disease in a prospective randomised study. One hundred eleven consecutive patients (age: 36-77, mean 58.8 years) scheduled for routine angioplasty due to stable coronary disease were randomised to receive BMS (Chopin II(TM), Balton, Poland) or paclitaxel eluting stent (Chopin Luc(TM), Balton, Poland) using the same metal platform. Only patients scheduled for angioplasty using the direct implantation technique of a single stent were randomised. The exclusion criteria included patients 〉 80 years, multivessel disease and reference diameter of the target vessel 〉 3.5 mm. In the BMS group (n = 55; 35 males and 20 females), the mean diameter of implanted stents was 3.09 ± 0.40 and the mean length was 11.37 ± 2.80, whereas in the DES group (n = 56; 34 males and 22 females) the mean stent sizes were 3.02 ± 0.34 and 17.90 ± 7.38 mm, respectively (p 〉 0.05 for length). The groups did not significantly differ regarding the frequency of stent implantation to particular coronary vessels. The direct stenting technique was attempted and failed, leading to the stents' implantation after predilatation in five patients in the BMS group and six patients in the DES group. Failure of stent implantation and subsequent implantation of another stent type was observed in no BMS patients and in one DES patient (NS). Although stent covering with lactate based drug eluting polymer may increase its stiffness, it does not affect

  2. Retrieval of a self-expanding metal stent after migration and incorporation in the omental bursa, using a gastroscopic-transgastric laparoscopic rendezvous technique.

    Science.gov (United States)

    Patrzyk, Maciej; Dierzek, Przemyslaw; Glitsch, Anne; Paul, Hartmut; Heidecke, Claus-Dieter

    2015-01-01

    Endoscopic drainage is a widely used treatment for pancreatic pseudocysts. Drainage-related complications may be related directly to the procedure or may occur later as stents migrate or erode into adjacent structures. Migration of a self-expanding metal stent into peritoneal cavity and incorporation in the omental bursa is rare. When endoscopic retrieval fails a combined laparoscopic-endoscopic (rendezvous technique) approach offers an alternative to open surgery. We report a case of successful gastroscopic-transgastric laparoscopic removal of a stent that was dislocated into the omental bursa after a ½ year observation period.

  3. Retrieval of a self-expanding metal stent after migration and incorporation in the omental bursa, using a gastroscopic-transgastric laparoscopic rendezvous technique

    Directory of Open Access Journals (Sweden)

    Maciej Patrzyk

    2015-01-01

    Full Text Available Endoscopic drainage is a widely used treatment for pancreatic pseudocysts. Drainage-related complications may be related directly to the procedure or may occur later as stents migrate or erode into adjacent structures. Migration of a self-expanding metal stent into peritoneal cavity and incorporation in the omental bursa is rare. When endoscopic retrieval fails a combined laparoscopic-endoscopic (rendezvous technique approach offers an alternative to open surgery. We report a case of successful gastroscopic-transgastric laparoscopic removal of a stent that was dislocated into the omental bursa after a ΍ year observation period.

  4. Percutaneous placement of ureteral stent

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung Hyup; Park, Jae Hyung; Han, Joon Koo; Han, Man Chung [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1990-12-15

    Antegrade placement of ureteral stents has successfully achieved in 41 of 46 ureters. When it was difficult to advance ureteral stents through the lesion, it was facilitated by retrograde guide-wire snare technique through urethra. Complications associated with the procedure were non-function of ureteral stent by occlusion, upward migration,and spontaneous fracture of ureteral stent. These complications were managed by percutaneous nephrostomy and removal of ureteral stents by guide-wire snare technique and insertion of a new ureteral stent. While blood cell in urine was markedly increased in about 50% of patients following the procedure.

  5. The acute changes of fractional flow reserve in DK (double kissing), crush, and 1-stent technique for true bifurcation lesions.

    Science.gov (United States)

    Ye, Fei; Zhang, Jun-Jie; Tian, Nai-Liang; Lin, Song; Liu, Zhi-Zhong; Kan, Jing; Xu, Hai-Mei; Zhu, Zhongsheng; Chen, Shao-Liang

    2010-08-01

    While many studies confirmed the importance of fractional flow reserve (FFR) in guiding complex percutaneous coronary interventions (PCI), data regarding the significance of FFR for bifurcation lesions are still lacking. Between October 2008 and October 2009, 51 patients with true bifurcation lesions were consecutively enrolled and randomized into double kissing (DK) crush (n = 25), and provisional 1-stent (n = 26) groups. FFR measurements at baseline and hyperemia were measured at pre-PCI, post-PCI, and at 8-month follow-up. Clinical follow-ups were available in 100% of patients while only 33% of patients underwent angiographic follow-up. Baseline clinical and angiographic characteristics were matched between the 2 groups. Pre-PCI FFR of the main branch (MB) in the DK group was 0.76 +/- 0.15, which was significantly lower than in the provisional 1-stent group (0.83 +/- 0.10, P = 0.029). This difference disappeared after the PCI procedure (0.92 +/- 0.04 vs. 0.92 +/- 0.05, P = 0.58). There were no significant differences in terms of baseline, angiographic, procedural indexes, and FFR of side branch (SB) between the 2 treatment arms. However, immediately after PCI, the patient with DK crush had higher FFR in the SB as compared to the provisional 1-stent group (0.94 +/- 0.03 vs. 0.90 +/- 0.08, P = 0.028, respectively) and also they had lower diameter stenosis (8.59 +/- 6.41% vs. 15.62 +/- 11.69%, P = 0.015, respectively). In the acute phase, immediately after PCI for bifurcation lesion, DK crush stenting was associated with higher FFR and lower residual diameter stenosis in the SB, as compared with the provisional 1-stent group.

  6. On-site customization of silicone stents: towards optimal palliation of complex airway conditions.

    Science.gov (United States)

    Breen, David P; Dutau, Hervé

    2009-01-01

    Stents may be indicated as treatment of benign and malignant conditions of the central airways. Occasionally, aberrant and/or distorted airways secondary to therapy or surgery may preclude the use of commercially manufactured stents. The customization of stents is well described for nonpulmonary diseases, but to date there are only limited data in the literature on prosthesis customization for airway disease. To review all the different techniques and indications of on-site silicone stent customizations and their related complications. A retrospective study was undertaken to identify all patients who underwent treatment with a silicone stent which was customized on site by the physician. The study included subjects treated during an 8-year period. Forty-nine on-site customizations were performed in 43 patients (34 males, mean age 63 +/- 5.2 years). Stent customization was performed in 5.4% of the cases. Stent customization was performed for malignant and benign disease in 35 (81.3%) and 8 (18.7%) cases, respectively. In all cases, the stent deployed successfully and performed well while in situ. Stent manipulation did not increase complications. Customization of airway stents by the physician can lead to successful stenting of difficult airway lesions with a good short-term safety profile. Standard commercially available stents may have resulted in suboptimal management of complex airway pathologies. A prospective study is warranted to further investigate the safety profile and complications associated with stent customization. Copyright 2009 S. Karger AG, Basel.

  7. Fibre laser cutting of polycaprolactone sheet for stents manufacturing: A feasibility study

    Science.gov (United States)

    Guerra, Antonio J.; Farjas, Jordi; Ciurana, Joaquim

    2017-10-01

    The role of the stent is temporary and it is limited to the intervention and shortly thereafter. Bioresorbable polymer stents were introduced to overcome this problem, making the stent manufacturing process rather difficult considering the complexity of the material. The stent forecast sale makes constant technology development necessary on this field. The adaptation of the laser manufacturing industry to these new materials is costly, thus further studies employing different sorts of lasers are necessary. This paper aims to explore the feasibility of 1.08 μm wavelength fibre laser to cut polycaprolactone sheet, which is especially interesting for long-term implantable devices, such as stents. The laser cut samples were analysed by Differential Scanning Calorimetry (DSC), Tensile Stress Test, and Optical Microscopy in order to study the effects of the laser process over the workpiece. The parameters measured were: taper angle, dimensional precision, material structure changes and mechanical properties changes. Results showed a dimensional precision above 95.75% with a taper angle lower than 0.033°. The laser ablation process has exhibited a minor influence upon material properties. Results exhibit the feasibility of fibre laser to cut polycaprolactone, making the fibre laser an alternative to manufacture stents.

  8. Brachytherapy and percutaneous stenting in the treatment of cholangiocarcinoma: A prospective randomised study

    International Nuclear Information System (INIS)

    Valek, Vlastimil; Kysela, Petr; Kala, Zdenek; Kiss, Igor; Tomasek, Jiri; Petera, Jiri

    2007-01-01

    Purpose: To evaluate the effect of radiation therapy including intraluminal brachyterapy with iridium-192 on survival of patients with malignant biliary strictures (cholangiocarcinoma, histologically improved) treated with metallic stent in a prospective randomised study. Method and materials: In the prospective randomised study, 21 patients with cholangiocarcinoma were treated with implantation of percutaneous stents followed with intraluminal Ir-192 brachytherapy (mean dose 30 Gy) and external radiotherapy (mean dose 50 Gy) and 21 patients were treated only with stents insertion. We did not find any statistically significant differences in age and tumor localization between these two groups of patients. Results: All the patients died. In the group of patients treated with brachytherapy and with stent implantation, the mean survival time was 387.9 days. In the group of patients treated only with stent insertion the mean survival was 298 days. In effort to eliminate possible effect of external radiotherapy we treated the control group of eight patients with cholangiocarcinoma by stent insertion and brachyterapy only. Conclusion: Our results show that combined radiation therapy could extend the survival in the patients with cholangiocarcinoma obstruction

  9. Strategy for optimal side-branch positioning of bioresorbable vascular scaffolds in dedicated 2-stent techniques: Insights from optical coherence tomography

    International Nuclear Information System (INIS)

    Miyazaki, Tadashi; Costopoulos, Charis; Sato, Katsumasa; Naganuma, Toru; Panoulas, Vasileios F.; Figini, Filippo; Latib, Azeem; Colombo, Antonio

    2014-01-01

    We present a case of a left anterior descending artery/diagonal branch bifurcation successfully treated with a dedicated 2-stent technique utilizing bioresorbable vascular scaffolds, where the bifurcation angle did not strictly allow a T-stenting approach. We also propose a strategy to avoid or reduce scaffold overlap in the main branch, especially important in view of the bulkier size of these novel devices

  10. The Efficacy of the Coaxial Technique Using a 6-Fr Introducer Sheath in Stent Placement for Treating the Obstructions Proximal to the Descending Colon

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Il Soo; Park, Sang Woo; Hwang, Dae Yong; Seong, Moo Kyung; Joh, Hee Kyung; Yoon, So Young; Cho, Yo Han; Choe, Won Hyeok [Konkuk University Hospital, Seoul (Korea, Republic of)

    2011-02-15

    We wanted to evaluate the efficacy of stent placement using the coaxial technique with a stiff, long introducer sheath in patients with technical failure using an angiographic catheter for the obstructions proximal to the descending colon. Self-expandable metallic stent placement was attempted under fluoroscopy-guidance in 77 consecutive patients who had malignant colorectal obstruction. Stent placement was performed using an angiographic catheter and a guide wire. If the angiographic catheter could not be advanced over the guide wire into the obstructive lesions proximal to the descending colon, then a 6-Fr introducer sheath was used. The technical success rate, the clinical success rate and the complications were analyzed. Successful stent placement was achieved in 75 of 77 patients (97%). The angiographic catheter failed to advance into the obstructive lesions of 11 patients (M:F = 7:4: mean age, 65.5 years) whose lesions were at the level of the splenic flexure or transverse colon. Therefore, the coaxial technique was implemented in all these 11 patients using a 6-Fr stiff introducer sheath and then the stent placement was successful. There were no complications related to the use of a stiff introducer sheath. Clinical success, which was defined as relief of clinical obstructive bowel symptoms, was obtained within 24 hours in all of patients. The coaxial technique using a stiff introducer sheath can increase the technical success of fluoroscopy-guided, self-expandable metallic stent placement in patients with colonic obstruction proximal to the descending colon

  11. The Efficacy of the Coaxial Technique Using a 6-Fr Introducer Sheath in Stent Placement for Treating the Obstructions Proximal to the Descending Colon

    International Nuclear Information System (INIS)

    Chang, Il Soo; Park, Sang Woo; Hwang, Dae Yong; Seong, Moo Kyung; Joh, Hee Kyung; Yoon, So Young; Cho, Yo Han; Choe, Won Hyeok

    2011-01-01

    We wanted to evaluate the efficacy of stent placement using the coaxial technique with a stiff, long introducer sheath in patients with technical failure using an angiographic catheter for the obstructions proximal to the descending colon. Self-expandable metallic stent placement was attempted under fluoroscopy-guidance in 77 consecutive patients who had malignant colorectal obstruction. Stent placement was performed using an angiographic catheter and a guide wire. If the angiographic catheter could not be advanced over the guide wire into the obstructive lesions proximal to the descending colon, then a 6-Fr introducer sheath was used. The technical success rate, the clinical success rate and the complications were analyzed. Successful stent placement was achieved in 75 of 77 patients (97%). The angiographic catheter failed to advance into the obstructive lesions of 11 patients (M:F = 7:4: mean age, 65.5 years) whose lesions were at the level of the splenic flexure or transverse colon. Therefore, the coaxial technique was implemented in all these 11 patients using a 6-Fr stiff introducer sheath and then the stent placement was successful. There were no complications related to the use of a stiff introducer sheath. Clinical success, which was defined as relief of clinical obstructive bowel symptoms, was obtained within 24 hours in all of patients. The coaxial technique using a stiff introducer sheath can increase the technical success of fluoroscopy-guided, self-expandable metallic stent placement in patients with colonic obstruction proximal to the descending colon

  12. Effect of cilostazol on in-stent neointimal hyperplasia after coronary artery stenting. A quantitative coronary angiography and volumetric intravascular ultrasound study

    International Nuclear Information System (INIS)

    Min, Pil-Ki; Jung, Jae-Hun; Ko, Young-Guk; Choi, Donghoon; Jang, Yangsoo; Shim, Won-Heum

    2007-01-01

    This study was designed to investigate the efficacy of cilostazol on the prevention of in-stent neointimal hyperplasia as measured by both quantitative coronary angiography (CAG) and volumetric intravascular ultrasound (IVUS). Fifty-nine patients (39 men, age 62 years) undergoing elective coronary stenting were randomly assigned to receive aspirin plus clopidogrel or ticlopidine (Group I, n=28, 30 lesions) or aspirin plus clopidogrel or ticlopidine plus cilostazol (Group II, n=31, 35 lesions). CAG and IVUS were performed and repeated at 6 months to assess the primary endpoints of minimal luminal diameter (MLD) and in-stent neointimal hyperplasia volume. Follow-up CAG was performed on all patients and follow-up IVUS study was available for 50 lesions in 48 patients (24 lesions in Group I, 26 in Group II). There were no significant differences in the baseline angiographic data between the 2 groups. At 6 months follow-up, in-stent MLD was 1.90±0.76 mm in Group I and 2.41±0.85 mm in Group II (p=0.006). Volumetric IVUS at 6 months demonstrated that in-stent intimal hyperplasia volume per stent length was 2.2±1.4 mm 3 /mm in Group I and 1.0±0.5 mm 3 /mm in Group II (p=0.001). Triple antiplatelet therapy including cilostazol seems to be more effective at preventing in-stent neointimal hyperplasia than a dual antiplatelet regimen. (author)

  13. Ferromagnetic Bare Metal Stent for Endothelial Cell Capture and Retention.

    Science.gov (United States)

    Uthamaraj, Susheil; Tefft, Brandon J; Hlinomaz, Ota; Sandhu, Gurpreet S; Dragomir-Daescu, Dan

    2015-09-18

    Rapid endothelialization of cardiovascular stents is needed to reduce stent thrombosis and to avoid anti-platelet therapy which can reduce bleeding risk. The feasibility of using magnetic forces to capture and retain endothelial outgrowth cells (EOC) labeled with super paramagnetic iron oxide nanoparticles (SPION) has been shown previously. But this technique requires the development of a mechanically functional stent from a magnetic and biocompatible material followed by in-vitro and in-vivo testing to prove rapid endothelialization. We developed a weakly ferromagnetic stent from 2205 duplex stainless steel using computer aided design (CAD) and its design was further refined using finite element analysis (FEA). The final design of the stent exhibited a principal strain below the fracture limit of the material during mechanical crimping and expansion. One hundred stents were manufactured and a subset of them was used for mechanical testing, retained magnetic field measurements, in-vitro cell capture studies, and in-vivo implantation studies. Ten stents were tested for deployment to verify if they sustained crimping and expansion cycle without failure. Another 10 stents were magnetized using a strong neodymium magnet and their retained magnetic field was measured. The stents showed that the retained magnetism was sufficient to capture SPION-labeled EOC in our in-vitro studies. SPION-labeled EOC capture and retention was verified in large animal models by implanting 1 magnetized stent and 1 non-magnetized control stent in each of 4 pigs. The stented arteries were explanted after 7 days and analyzed histologically. The weakly magnetic stents developed in this study were capable of attracting and retaining SPION-labeled endothelial cells which can promote rapid healing.

  14. Robot-assisted laparoscopic pyeloureterostomy in infants with duplex systems and upper pole hydronephrosis: Variations in double-J ureteral stenting techniques.

    Science.gov (United States)

    Baek, Minki; Au, Jason; Huang, Gene O; Koh, Chester J

    2017-04-01

    We describe our experience with robot-assisted laparoscopic (RAL) pyeloureterostomy in infants with duplex systems and upper pole hydronephrosis with an emphasis on the various double J (DJ) ureteral stent placement techniques. We used our RAL pyeloureterostomy technique in two female infants with duplex systems and upper pole hydronephrosis. For case 1, we introduced the DJ stent and placed it in the recipient lower pole ureter during the robotic operation in an antegrade fashion. For case 2, we inserted the DJ stent during retrograde pyelography prior to the robotic procedure in a retrograde fashion, and the proximal portion of the stent was placed across the anastomosis into the upper pole renal pelvis. Postoperatively, each of the patients were discharged on postoperative day 1 without complications. The postoperative renal ultrasound at 3 months demonstrated marked improvement of the right upper pole hydronephrosis in both patients. RAL pyeloureterostomy represents a minimally invasive option for upper tract reconstruction of duplex systems with upper pole hydronephrosis in infants. The DJ stent can be placed at the beginning or during the procedure. The stent can be placed in the lower pole ureter or across the anastomosis into the upper pole renal pelvis. Copyright © 2017 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

  15. Colonic Stents for Colorectal Cancer Are Seldom Used and Mainly for Palliation of Obstruction: A Population-Based Study

    Directory of Open Access Journals (Sweden)

    Anna M. Borowiec

    2016-01-01

    Full Text Available Self-expandable stents for obstructing colorectal cancer (CRC offer an alternative to operative management. The objective of the study was to determine stent utilization for CRC obstruction in the province of Ontario between April 1, 2000, and March 30, 2009. Colonic stent utilization characteristics, poststent insertion health outcomes, and health care encounters were recorded. 225 patients were identified over the study period. Median age was 69 years, 2/3 were male, and 2/3 had metastatic disease. Stent use for CRC increased over the study period and gastroenterologists inserted most stents. The median survival after stent insertion was 199 (IQR, 69–834 days. 37% of patients required an additional procedure. Patients with metastatic disease were less likely to go on to surgery (HR 0.14, 95% CI 0.06–0.32, p<0.0001. There were 2.4/person-year emergency department visits (95% CI 2.2–2.7 and 2.3 hospital admissions/person-year (95% CI 2.1–2.5 following stent insertion. Most admissions were cancer or procedure related or for palliation. Factors associated with hospital admissions were presence of metastatic disease, lack of chemotherapy treatment, and stoma surgery. Overall the use of stents for CRC obstruction remains low. Stents are predominantly used for palliation with low rates of postinsertion health care encounters.

  16. Clinical feasibility of a new through-the-scope fully covered esophageal self-expandable metallic stent: an in vivo animal study.

    Science.gov (United States)

    Cheon, Young Koog; Lee, Tae Yoon; Sung, In Kyung; Shim, Chan Sup

    2014-01-01

    Most delivery devices used for esophageal stents for obstructing esophageal cancer have a diameter of 5-8 mm, a size that is too large to pass through the endoscopic working channel. The conventional esophageal stent requires multiple endoscopic procedures for implantation. The purpose of the present study was to evaluate the clinical feasibility of a newly developed fully covered, self-expanding, through-the-scope (TTS) esophageal stent in a porcine model. Eight mini pigs were used. Each animal underwent placement of a fully covered TTS stent (Hanarostent® Esophagus TTS) and the upper part of the stent was fixed by suturing with nylon. Fluoroscopy was carried out every week to assess migration of the stent. Follow-up endoscopy was done every month for 3 months to evaluate the status of the membrane, stent mesh, grade of tissue hyperplasia, and mucosal changes at both ends of the stent. All stents were successfully and easily deployed, and were placed without any distortion in the stent or without rupture of the membrane. In two cases, stent migration was observed after 8 weeks. No case of membrane disruption, stent mesh disruption or tissue hyperplasia at either end of the stent was found at the completion of the study. Our findings indicate that the new fully covered self-expanding TTS esophageal stent is easy and simple to implant, and no significant distortion of mesh or disruption of membrane was observed. © 2013 The Authors. Digestive Endoscopy © 2013 Japan Gastroenterological Endoscopy Society.

  17. Preoperative biliary drainage using a fully covered self-expandable metallic stent for pancreatic head cancer: A prospective feasibility study.

    Science.gov (United States)

    Togawa, Osamu; Isayama, Hiroyuki; Kawakami, Hiroshi; Nakai, Yousuke; Mohri, Dai; Hamada, Tsuyoshi; Kogure, Hirofumi; Kawakubo, Kazumichi; Sakamoto, Naoya; Koike, Kazuhiko; Kita, Hiroto

    2018-01-01

    The role of endoscopic preoperative biliary drainage (PBD) for pancreatic head cancer is controversial because of the high incidence of stent occlusion before surgery. This study was performed to evaluate the feasibility and safety of PBD using a fully covered self-expandable metallic stent (FCSEMS). This multicenter prospective study involved 26 patients treated for pancreatic head cancer with distal bile duct obstruction from April 2011 to March 2013. An FCSEMS was endoscopically placed in 24 patients. Among these, 7 patients were diagnosed with unresectable cancer, and 17 underwent surgery at a median of 18 days after FCSEMS placement. The main outcome measure was preoperative and postoperative adverse events. Two adverse events (cholecystitis and insufficient resolution of jaundice) occurred between FCSEMS placement and surgery (12%). Postoperative adverse events occurred in eight patients (47%). The cumulative incidence of stent-related adverse events 4 and 8 weeks after FCSEMS placement among the 24 patients who underwent this procedure were 19%. PBD using an FCSEMS is feasible in patients with resectable pancreatic head cancer. Placement of an FCSEMS can be an alternative PBD technique when surgery without delay is impossible. A larger randomized controlled trial is warranted.

  18. Detailing Radio Frequency Heating Induced by Coronary Stents: A 7.0 Tesla Magnetic Resonance Study

    Science.gov (United States)

    Santoro, Davide; Winter, Lukas; Müller, Alexander; Vogt, Julia; Renz, Wolfgang; Özerdem, Celal; Grässl, Andreas; Tkachenko, Valeriy; Schulz-Menger, Jeanette; Niendorf, Thoralf

    2012-01-01

    The sensitivity gain of ultrahigh field Magnetic Resonance (UHF-MR) holds the promise to enhance spatial and temporal resolution. Such improvements could be beneficial for cardiovascular MR. However, intracoronary stents used for treatment of coronary artery disease are currently considered to be contra-indications for UHF-MR. The antenna effect induced by a stent together with RF wavelength shortening could increase local radiofrequency (RF) power deposition at 7.0 T and bears the potential to induce local heating, which might cause tissue damage. Realizing these constraints, this work examines RF heating effects of stents using electro-magnetic field (EMF) simulations and phantoms with properties that mimic myocardium. For this purpose, RF power deposition that exceeds the clinical limits was induced by a dedicated birdcage coil. Fiber optic probes and MR thermometry were applied for temperature monitoring using agarose phantoms containing copper tubes or coronary stents. The results demonstrate an agreement between RF heating induced temperature changes derived from EMF simulations versus MR thermometry. The birdcage coil tailored for RF heating was capable of irradiating power exceeding the specific-absorption rate (SAR) limits defined by the IEC guidelines by a factor of three. This setup afforded RF induced temperature changes up to +27 K in a reference phantom. The maximum extra temperature increase, induced by a copper tube or a coronary stent was less than 3 K. The coronary stents examined showed an RF heating behavior similar to a copper tube. Our results suggest that, if IEC guidelines for local/global SAR are followed, the extra RF heating induced in myocardial tissue by stents may not be significant versus the baseline heating induced by the energy deposited by a tailored cardiac transmit RF coil at 7.0 T, and may be smaller if not insignificant than the extra RF heating observed under the circumstances used in this study. PMID:23185498

  19. Detailing radio frequency heating induced by coronary stents: a 7.0 Tesla magnetic resonance study.

    Directory of Open Access Journals (Sweden)

    Davide Santoro

    Full Text Available The sensitivity gain of ultrahigh field Magnetic Resonance (UHF-MR holds the promise to enhance spatial and temporal resolution. Such improvements could be beneficial for cardiovascular MR. However, intracoronary stents used for treatment of coronary artery disease are currently considered to be contra-indications for UHF-MR. The antenna effect induced by a stent together with RF wavelength shortening could increase local radiofrequency (RF power deposition at 7.0 T and bears the potential to induce local heating, which might cause tissue damage. Realizing these constraints, this work examines RF heating effects of stents using electro-magnetic field (EMF simulations and phantoms with properties that mimic myocardium. For this purpose, RF power deposition that exceeds the clinical limits was induced by a dedicated birdcage coil. Fiber optic probes and MR thermometry were applied for temperature monitoring using agarose phantoms containing copper tubes or coronary stents. The results demonstrate an agreement between RF heating induced temperature changes derived from EMF simulations versus MR thermometry. The birdcage coil tailored for RF heating was capable of irradiating power exceeding the specific-absorption rate (SAR limits defined by the IEC guidelines by a factor of three. This setup afforded RF induced temperature changes up to +27 K in a reference phantom. The maximum extra temperature increase, induced by a copper tube or a coronary stent was less than 3 K. The coronary stents examined showed an RF heating behavior similar to a copper tube. Our results suggest that, if IEC guidelines for local/global SAR are followed, the extra RF heating induced in myocardial tissue by stents may not be significant versus the baseline heating induced by the energy deposited by a tailored cardiac transmit RF coil at 7.0 T, and may be smaller if not insignificant than the extra RF heating observed under the circumstances used in this study.

  20. Transluminal radio-frequency thermal ablation using a stent-type electrode: an experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Sun; Rhim, Hyun Chul [Hanyang University College of Medicine, Seoul (Korea, Republic of); Song, Ho Young [Asan Medical Center, Seoul (Korea, Republic of)] [and others

    2003-06-01

    To assess the feasibility of transluminal radiofrequency thermal ablation using a stent-type electrode and to determine, by means of in-vivo and in-vivo animal studies, the appropriate parameters. In-vivo: the radiofrequency electrode used was a self-expandable nitinol stent with 1cm insulated ends. A stent was placed in the portal vein of bovine liver, and ablations at target temperatures of 70, 80, 90, and 100 .deg. C were performed. Ablated sizes were measured longitudinally. In vivo: four mongrel dogs were anesthetized, and a stent was inserted in the common bile duct under fluoroscopic guidance through an ultrasound-guided gall bladder puncture site. The ablation temperature was set at 80 .deg. C, and each dog underwent proximal and distal esophageal ablations lasting 12 minutes. They were sacrificed immediately. In-vivo: ablated sizes showed significant correlation with target temperatures (r>0.04; p<0.05). Although most lesions were fusiform, dumbbell-shaped lesions with central thinning were found in two cases in the 70 .deg. C group. In all cases in the 70 .deg. C and 80 .deg. C group, the length of the insulated segment was less than 1cm. In-vivo: at microscopy, tissues at the center of the biliary stent showed more prominent pathological change than those at the periphery while those remote from the stent showed minimal or no change. In esophageal ablations, the mean highest temperature was 48.6 .deg. C. Microscopy demonstrated the destruction and shedding of mucosa, edema, and coagulation necrosis of submucosa, but in muscle layers no abnormalities were apparent. Transluminal radio-frequency thermal ablation using a stent-type electrode may be useful for elongating patency. The appropriate target temperature for biliary ablation is 80 .deg. C.

  1. Morphology characterization and biocompatibility study of PLLA (Poly-L-Llactid-Acid) coating chitosan as stent for coronary heart disease

    Science.gov (United States)

    Widiyanti, Prihartini; Paramadini, Adanti W.; Jabbar, Hajria; Fatimah, Inas; Nisak, Fadila N. K.; Puspitasari, Rahma A.

    2016-03-01

    Cardiovascular disease is a global disease with high urgency. In the severe case of coronary heart disease while a blockage in the coronary arteries reach 75% or more, the patient required stent implantation. Stents are made of metal which has many limitations that can lead to blood clots and stent incompatibility toward the size of the blood vessels. There is a metal stent replacement solution that made from polymer material which is biocompatible. PLLA also has biocompatibility and good mechanical strength. PLLA stent will be coated with chitosan as a candidate for drug-coated stents which is able to work as a drug carrier. The aim of this study is to know the morphology information and biocompability status of PLLA coating chitosan as candidate of heart stent. Morphological results using SEM showed a smooth surface structure which reinforced clinical standard of stent material. Results of cytotoxicity test by MTT Assay method showed that the result of four samples in this experiment living cells is reached 90% which is non toxic and safe to use in the human body. %). The conclusion of this study is PLLA is polymer has potency to be used as stent material.

  2. Impact and Effectiveness of Dual Aspiration Technique in Stent-Assisted Mechanical Thrombectomy: Recent Improvements in Acute Stroke Management

    Energy Technology Data Exchange (ETDEWEB)

    Hopf-Jensen, S., E-mail: hopfsi@diako.de; Preiß, M.; Marques, L.; Lehrke, S. [Diakonissenhospital Flensburg, Department of Diagnostic and Interventional Radiology and Neuroradiology (Germany); Schattschneider, J.; Stolze, H. [Diakonissenhospital Flensburg, Department of Neurology (Germany); Müller-Hülsbeck, S. [Diakonissenhospital Flensburg, Department of Diagnostic and Interventional Radiology and Neuroradiology (Germany)

    2016-11-15

    Background and PurposeTo evaluate feasibility and impact of dual aspiration technique (DAT) within stent-assisted mechanical thrombectomy on procedural parameters and clinical outcome.Materials and MethodsWithin 16 months, 76 consecutive patients (mean age 70.7 year; range 33–89) underwent stent-assisted mechanical thrombectomy. Of 52 enrolled patients (68.4 %) with occlusion of the anterior circulation, 22 patients (42.3 %) underwent DAT; 30 patients (57.7 %) were treated in conventional monoaspiration technique (MAT). Epidemiological data, clinical and imaging characteristics (mRS, NIHSS, ASPECTS) as well as procedural details were analyzed (TICI, number of retrieval, procedure time). Clinical outcome was determined with mRS at discharge and after 90 days.ResultsIn the context of DAT additional carotid artery stenting was required in 45.5 % (10/22) in underlying tandem lesion (vs. 0/30 MAT). No differences were found in NIHSS at admission (MAT: 20.5, range 15–29; DAT: 18.6; range 11–25), mRS at admission (MAT: 4.6 vs. DAT: 4.57) or ASPECT score (MAT: 8.3, ±1.5; DAT: 8.4, ±1.5; P > 0.05). TICI ≥ 2b/3 was conducted in 90 % (MAT) and 100 % (DAT), respectively. The procedure time was longer in the MAT group (65 min, ±25.9, range 18–126) compared to the DAT group (49.7 min, ±15, range 32–101; P = 0.016). The clinical outcome increased from admission to discharge and in follow-up after 90 days (mRS ≥ 2: MAT: 53.3 %, DAT: 54.5 %; P > 0.05).ConclusionsThe dual aspiration technique with an additional intermediate guide catheter placed closed to the stent retriever leads to decreased procedure time in the anterior circulation. Even in cases with higher thrombus load and treated in DAT, clinical outcome improved.

  3. Feasibility study using a Ni-Ti stent and electronic portal imaging to localize the prostate during radiotherapy.

    Science.gov (United States)

    Carl, Jesper; Lund, Bente; Larsen, Erik Hoejkjaer; Nielsen, Jane

    2006-02-01

    A new method for localization of the prostate during external beam radiotherapy is presented. The method is based on insertion of a thermo-expandable Ni-Ti stent. The stent is originally developed for treatment of bladder outlet obstruction caused by benign hyperplasia. The radiological properties of the stent are used for precise prostate localization during treatment using electronic portal images. Patients referred for intended curative radiotherapy and having a length of their prostatic urethra in the range from 25 to 65 mm were included. Pairs of isocentric orthogonal portal images were used to determine the 3D position at eight different treatment sessions for each patient. Fourteen patients were enrolled in the study. The data obtained demonstrated that the stent position was representative of the prostate location. The stent may also improve delineation of the prostate GTV, and prevent obstruction of bladder outlet during treatment. Precision in localization of the stent was less than 1 mm. Random errors in stent position were left-right 1.6 mm, cranial-caudal 2.2 mm and anterior-posterior 3.2 mm. In four of 14 patients a dislocation of the stent to the bladder occurred. Dislocation only occurred in patients with length of prostatic urethra less than 40 mm. A new method for radiological high precision localization of the prostate during radiotherapy is presented. The method is based on insertion of a standard Ni-Ti thermo-expandable stent, designed for treatment of benign prostate hyperplasia.

  4. Evolution of the degradation mechanism of pure zinc stent in the one-year study of rabbit abdominal aorta model.

    Science.gov (United States)

    Yang, Hongtao; Wang, Cong; Liu, Chaoqiang; Chen, Houwen; Wu, Yifan; Han, Jintao; Jia, Zichang; Lin, Wenjiao; Zhang, Deyuan; Li, Wenting; Yuan, Wei; Guo, Hui; Li, Huafang; Yang, Guangxin; Kong, Deling; Zhu, Donghui; Takashima, Kazuki; Ruan, Liqun; Nie, Jianfeng; Li, Xuan; Zheng, Yufeng

    2017-11-01

    In the present study, pure zinc stents were implanted into the abdominal aorta of rabbits for 12 months. Multiscale analysis including micro-CT, scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM) and histological stainings was performed to reveal the fundamental degradation mechanism of the pure zinc stent and its biocompatibility. The pure zinc stent was able to maintain mechanical integrity for 6 months and degraded 41.75 ± 29.72% of stent volume after 12 months implantation. No severe inflammation, platelet aggregation, thrombosis formation or obvious intimal hyperplasia was observed at all time points after implantation. The degradation of the zinc stent played a beneficial role in the artery remodeling and healing process. The evolution of the degradation mechanism of pure zinc stents with time was revealed as follows: Before endothelialization, dynamic blood flow dominated the degradation of pure zinc stent, creating a uniform corrosion mode; After endothelialization, the degradation of pure zinc stent depended on the diffusion of water molecules, hydrophilic solutes and ions which led to localized corrosion. Zinc phosphate generated in blood flow transformed into zinc oxide and small amounts of calcium phosphate during the conversion of degradation microenvironment. The favorable physiological degradation behavior makes zinc a promising candidate for future stent applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Predictors of early stent occlusion among plastic biliary stents.

    Science.gov (United States)

    Khashab, Mouen A; Kim, Katherine; Hutfless, Susan; Lennon, Anne Marie; Kalloo, Anthony N; Singh, Vikesh K

    2012-09-01

    A major disadvantage of plastic biliary stents is their short patency rates. The aim of this study was to identify predictors of early stent occlusion among patients receiving conventional plastic biliary stents. Early stent occlusion was defined as worsening cholestatic liver test results of a severity sufficiently significant to warrant ERCP with stent exchange prior to the planned stent exchange, or as symptoms of cholangitis. The association of cumulative stent diameter, demographics, stricture location, procedure indication, Charlson comorbidity index, history of prior early stent occlusion, presence of gallbladder, and performance of sphincteromy with the occurrence of early stent occlusion was studied using logistic regression and multivariate analysis. Our patient cohort comprised 343 patients (mean age 59.3 years) who underwent 561 ERCP procedures with the placement of one or more plastic biliary stents (mean number of stents per procedure 1.2, mean total diameter of stents per procedure 12 Fr). Early stent occlusion occurred in 73 (13 %) procedures. Female gender was protective against early stent occlusion (adjusted OR 0.54, 95 % CI 0.32-0.90, p = 0.02), while hilar stricture location was independently associated with a significantly increased risk of early stent occlusion (adjusted OR 3.41, 95 % CI 1.68-6.90, p = 0.0007). Early occlusion of conventional biliary stents occurred in 13 % of cases. While female gender decreased the risk of early stent occlusion, hilar stricture location was a significant predictor of early stent occlusion. Our results suggest that physicians should consider early elective stent exchange in patients with hilar strictures.

  6. Endoscopic bilateral stent-in-stent placement for malignant hilar obstruction using a large cell type stent.

    Science.gov (United States)

    Park, Jin Myung; Lee, Sang Hyub; Chung, Kwang Hyun; Jang, Dong Kee; Ryu, Ji Kon; Kim, Yong-Tae; Lee, Jae Min; Paik, Woo Hyun

    2016-12-01

    Bilateral stent-in-stent (SIS) self-expandable metal stent placement is technically challenging for palliation of unresectable malignant hilar obstruction. In the SIS technique, the uniform large cell type biliary stent facilitates contralateral stent deployment through the mesh of the first metallic stent. This study aimed to assess the technical success and clinical effectiveness of this technique with a uniform large cell type biliary stent. Thirty-one patients who underwent bilateral SIS placement using a large cell type stent were reviewed retrospectively. All patients showed malignant hilar obstruction (Bismuth types II, III, IV) with different etiologies. Sixteen (51.6%) patients were male. The mean age of the patients was 67.0+/-14.0 years. Most patients were diagnosed as having hilar cholangiocarcinoma (58.1%) and gallbladder cancer (29.0%). Technical success rate was 83.9%. Success was achieved more frequently in patients without masses obstructing the biliary confluence (MOC) than those with MOC (95.2% vs 60.0%, P=0.03). Functional success rate was 77.4%. Complications occurred in 29.0% of the patients. These tended to occur more frequently in patients with MOC (50.0% vs 19.0%, P=0.11). Median time to recurrent biliary obstruction was 188 days and median survival was 175 days. The large cell type stent can be used efficiently for bilateral SIS placement in malignant hilar obstruction. However, the risk of technical failure increases in patients with MOC, and caution is needed to prevent complications for these patients.

  7. Mechanical characteristics of self-expandable metallic stents: in vitro study with three types of stress

    International Nuclear Information System (INIS)

    Lee, Byung Hee; Kim, Kie Hwan; Chin, Soo Yil

    1998-01-01

    To obtain objective and comparable data for mechanical characteristics of self-expandable metallic stents widely used in the treatment of biliary obstruction. The stents tested were the 6 and 8 mm-band Hanaro spiral stent, Gianturco-Rosch Z stent, Wallstent, Ultraflex stent, and Memotherm stent. Each was subjected to three types of load:point, area, and circular. We analyzed their mechanical characteristics (resistance force, expansile force, and elasticity) according to these three types of stress. With regard to point loads, the Memotherm stent showed the highest resistance force and expansile force. The 8 mm-band Hanaro stent showed the lowest resistance force and the Gianturco-Rosch Z stent and Ultraflex stent showed lower expansile force. With regard to area loads, the Ultraflex stent showed the highest resistance force. The 6 mm-band Hanaro stent, Gianturco-Rosch Z stent, and Ultraflex stent showed higher expansile force. The 8 mm-band Hanaro stent showed the lowest value in both resistance force and expansile force. For circular loads, the Memotherm stent showed the highest resistance force and the Ultraflex stent and Wallstent showed lower value. Under all types of stress, the Hanaro stent and Memotherm stent were completely elastic, and the Ultraflex stent and Wallstent showed a wide gap between resistance force and expansile force. In clinical practice, awareness of the mechanical characteristics of each stent might help in choosing the one which is most suitable, according to type of biliary obstruction. =20

  8. Mechanical characteristics of self-expandable metallic stents: in vitro study with three types of stress

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byung Hee; Kim, Kie Hwan; Chin, Soo Yil [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

    1998-09-01

    To obtain objective and comparable data for mechanical characteristics of self-expandable metallic stents widely used in the treatment of biliary obstruction. The stents tested were the 6 and 8 mm-band Hanaro spiral stent, Gianturco-Rosch Z stent, Wallstent, Ultraflex stent, and Memotherm stent. Each was subjected to three types of load:point, area, and circular. We analyzed their mechanical characteristics (resistance force, expansile force, and elasticity) according to these three types of stress. With regard to point loads, the Memotherm stent showed the highest resistance force and expansile force. The 8 mm-band Hanaro stent showed the lowest resistance force and the Gianturco-Rosch Z stent and Ultraflex stent showed lower expansile force. With regard to area loads, the Ultraflex stent showed the highest resistance force. The 6 mm-band Hanaro stent, Gianturco-Rosch Z stent, and Ultraflex stent showed higher expansile force. The 8 mm-band Hanaro stent showed the lowest value in both resistance force and expansile force. For circular loads, the Memotherm stent showed the highest resistance force and the Ultraflex stent and Wallstent showed lower value. Under all types of stress, the Hanaro stent and Memotherm stent were completely elastic, and the Ultraflex stent and Wallstent showed a wide gap between resistance force and expansile force. In clinical practice, awareness of the mechanical characteristics of each stent might help in choosing the one which is most suitable, according to type of biliary obstruction. =20.

  9. CT angiography after carotid artery stenting: assessment of the utility of adaptive statistical iterative reconstruction and model-based iterative reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Kuya, Keita; Shinohara, Yuki; Fujii, Shinya; Ogawa, Toshihide [Tottori University, Division of Radiology, Department of Pathophysiological Therapeutic Science, Faculty of Medicine, Yonago (Japan); Sakamoto, Makoto; Watanabe, Takashi [Tottori University, Division of Neurosurgery, Department of Brain and Neurosciences, Faculty of Medicine, Yonago (Japan); Iwata, Naoki; Kishimoto, Junichi [Tottori University, Division of Clinical Radiology Faculty of Medicine, Yonago (Japan); Kaminou, Toshio [Osaka Minami Medical Center, Department of Radiology, Osaka (Japan)

    2014-11-15

    Follow-up CT angiography (CTA) is routinely performed for post-procedure management after carotid artery stenting (CAS). However, the stent lumen tends to be underestimated because of stent artifacts on CTA reconstructed with the filtered back projection (FBP) technique. We assessed the utility of new iterative reconstruction techniques, such as adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR), for CTA after CAS in comparison with FBP. In a phantom study, we evaluated the differences among the three reconstruction techniques with regard to the relationship between the stent luminal diameter and the degree of underestimation of stent luminal diameter. In a clinical study, 34 patients who underwent follow-up CTA after CAS were included. We compared the stent luminal diameters among FBP, ASIR, and MBIR, and performed visual assessment of low attenuation area (LAA) in the stent lumen using a three-point scale. In the phantom study, stent luminal diameter was increasingly underestimated as luminal diameter became smaller in all CTA images. Stent luminal diameter was larger with MBIR than with the other reconstruction techniques. Similarly, in the clinical study, stent luminal diameter was larger with MBIR than with the other reconstruction techniques. LAA detectability scores of MBIR were greater than or equal to those of FBP and ASIR in all cases. MBIR improved the accuracy of assessment of stent luminal diameter and LAA detectability in the stent lumen when compared with FBP and ASIR. We conclude that MBIR is a useful reconstruction technique for CTA after CAS. (orig.)

  10. CT angiography after carotid artery stenting: assessment of the utility of adaptive statistical iterative reconstruction and model-based iterative reconstruction

    International Nuclear Information System (INIS)

    Kuya, Keita; Shinohara, Yuki; Fujii, Shinya; Ogawa, Toshihide; Sakamoto, Makoto; Watanabe, Takashi; Iwata, Naoki; Kishimoto, Junichi; Kaminou, Toshio

    2014-01-01

    Follow-up CT angiography (CTA) is routinely performed for post-procedure management after carotid artery stenting (CAS). However, the stent lumen tends to be underestimated because of stent artifacts on CTA reconstructed with the filtered back projection (FBP) technique. We assessed the utility of new iterative reconstruction techniques, such as adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR), for CTA after CAS in comparison with FBP. In a phantom study, we evaluated the differences among the three reconstruction techniques with regard to the relationship between the stent luminal diameter and the degree of underestimation of stent luminal diameter. In a clinical study, 34 patients who underwent follow-up CTA after CAS were included. We compared the stent luminal diameters among FBP, ASIR, and MBIR, and performed visual assessment of low attenuation area (LAA) in the stent lumen using a three-point scale. In the phantom study, stent luminal diameter was increasingly underestimated as luminal diameter became smaller in all CTA images. Stent luminal diameter was larger with MBIR than with the other reconstruction techniques. Similarly, in the clinical study, stent luminal diameter was larger with MBIR than with the other reconstruction techniques. LAA detectability scores of MBIR were greater than or equal to those of FBP and ASIR in all cases. MBIR improved the accuracy of assessment of stent luminal diameter and LAA detectability in the stent lumen when compared with FBP and ASIR. We conclude that MBIR is a useful reconstruction technique for CTA after CAS. (orig.)

  11. TOKYO criteria 2014 for transpapillary biliary stenting.

    Science.gov (United States)

    Isayama, Hiroyuki; Hamada, Tsuyoshi; Yasuda, Ichiro; Itoi, Takao; Ryozawa, Shomei; Nakai, Yousuke; Kogure, Hirofumi; Koike, Kazuhiko

    2015-01-01

    It is difficult to carry out meta-analyses or to compare the results of different studies of biliary stents because there is no uniform evaluation method. Therefore, a standardized reporting system is required. We propose a new standardized system for reporting on biliary stents, the 'TOKYO criteria 2014', based on a consensus among Japanese pancreatobiliary endoscopists. Instead of stent occlusion, we use recurrent biliary obstruction, which includes occlusion and migration. The time to recurrent biliary obstruction was estimated using Kaplan-Meier analysis with the log-rank test. We can evaluate both plastic and self-expandable metallic stents (uncovered and covered). We also propose specification of the cause of recurrent biliary obstruction, identification of complications other than recurrent biliary obstruction, indication of severity, measures of technical and clinical success, and a standard for clinical care. Most importantly, the TOKYO criteria 2014 allow comparison of biliary stent quality across studies. Because blocked stents can be drained not only using transpapillary techniques but also by an endoscopic ultrasonography-guided transmural procedure, we should devise an evaluation method that includes transmural stenting in the near future. © 2014 The Authors. Digestive Endoscopy © 2014 Japan Gastroenterological Endoscopy Society.

  12. Comparison of the Absorbable Polymer Sirolimus-Eluting Stent (MiStent) to the Durable Polymer Everolimus-Eluting Stent (Xience) (from the DESSOLVE I/II and ISAR-TEST-4 Studies).

    Science.gov (United States)

    Lansky, Alexandra J; Kastrati, Adnan; Edelman, Elazer R; Parise, Helen; Ng, Vivian G; Ormiston, John; Wijns, William; Byrne, Robert A

    2016-02-15

    We compared the outcomes of a novel, thin-strut, cobalt-chromium, absorbable, polymer sirolimus-eluting stent (APSES; MiStent) to the durable polymer cobalt-chromium everolimus-eluting stent (EES; Xience). A propensity-matched analysis was performed comparing data from the DES With Sirolimus and a Bioabsorbable Polymer for the Treatment of Patients With De Novo Lesions in the Native Coronary Arteries (DESSOLVE) I and II studies, evaluating the APSES to the EES arm of the Intracoronary Stenting and Angiographic Results: Test Efficacy of 3 Limus-Eluting Stents-4 study. Target lesion failure (TLF) and its components were evaluated at 12 months and annually to 3 years; 805 patients (APSES = 153; EES = 652) were included with propensity matching in 204 patients (APSES = 102; EES = 102). APSES compared with EES had lower TLF at 1 year (3.0% vs 8.0%, p = 0.12) driven by a difference in target lesion revascularization (TLR; 1% vs 6%, p = 0.05), with no difference in target vessel myocardial infarction (p = 0.56) or stent thrombosis (p = 0.31). At 3 years, TLF (5.0% vs 12.5%, p = 0.07) and TLR (2.0% vs 8.4%, p = 0.04) remained lower with APSES. By landmark analysis, there was no significant difference in TLF between 1 and 3 years (p = 0.36). In conclusion, in a propensity-matched analysis, the APSES demonstrated reduced clinically indicated TLR rates at 1 and 3 years compared with the durable polymer EES, with minimal accrual of events between 1 and 3 years. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Low-profile stent placement with the monorail technique for treatment of renal artery stenosis: midterm results of a prospective trial.

    Science.gov (United States)

    Müller-Hülsbeck, Stefan; Frahm, Christian; Behm, Charlotte; Schäfer, Phillip Jobst; Bolte, Hendrik; Heller, Martin; Jahnke, Thomas

    2005-07-01

    To determine feasibility, safety, and midterm patency of a monorail balloon stent device for the treatment of renal artery stenosis (RAS). During a period of 30 months, 47 patients (with severe hypertension, n=45; renal insufficiency, n=20) with 50 cases of RAS and indications for stent implantation (calcified ostial lesion, n=41; insufficient percutaneous transluminal angioplasty, n=6; dissection, n=3) were enrolled into the prospective evaluation. After predilation, 59 stents (Rx-Herculink 4 mm, n=2; 5 mm, n=19; 6 mm, n=35; 7 mm, n=3) were implanted under manometer control with use of the long-sheath technique (5 F; 6 F for 7-mm stents) via a femoral (n=44) or transbrachial approach (n=6). Parameters of hypertension and renal insufficiency were determined before and after the procedure and for a maximum of 18 months. Restenosis rate was determined with color duplex ultrasonography. Renal artery stent placement (mean diameter, 5.7 mm; mean length, 16 mm) was technically successful in all cases (100%). Mean blood pressure and serum creatinine level decreased from 177/93 mm Hg to 145/78 mm Hg and from 1.8 mg/dL to 1.5 mg/dL, respectively. Within 48 hours after the implantation, acute occlusions occurred in two patients, supposedly triggered by cholesterol embolization. Primary and primary assisted patency rates were 87% and 92% at 6 months and 75% and 84% at 18 months. Renal artery stent placement with the rapid-exchange monorail system is a safe procedure with promising patency rates. In combination with the long-sheath technique, adequate control of stent deployment is guaranteed during the entire intervention. The low profile of the device facilitates the use of small sheaths (5 F) to minimize access-site complications.

  14. Incidence of New Ischaemic Brain Lesions After Carotid Artery Stenting with the Micromesh Roadsaver Carotid Artery Stent: A Prospective Single-Centre Study

    Energy Technology Data Exchange (ETDEWEB)

    Ruffino, Maria Antonella, E-mail: mruffino@cittadellasalute.to.it [Azienda Ospedaliera Universitaria- Città della Salute e della Scienza di Torino, San Giovanni Battista Hospital, Vascular Radiology Unit, Department of Diagnostic Imaging and Radiotherapy (Italy); Faletti, Riccardo [University of Torino, Azienda Ospedaliera Universitaria- Città della Salute e della Scienza di Torino, San Giovanni Battista Hospital, Radiology Unit, Department of Surgical Sciences (Italy); Bergamasco, Laura [University of Torino, Azienda Ospedaliera Universitaria- Città della Salute e della Scienza di Torino, San Giovanni Battista Hospital, Department of Surgical Sciences (Italy); Fonio, Paolo [University of Torino, Azienda Ospedaliera Universitaria- Città della Salute e della Scienza di Torino, San Giovanni Battista Hospital, Radiology Unit, Department of Surgical Sciences (Italy); Righi, Dorico [Azienda Ospedaliera Universitaria- Città della Salute e della Scienza di Torino, San Giovanni Battista Hospital, Vascular Radiology Unit, Department of Diagnostic Imaging and Radiotherapy (Italy)

    2016-11-15

    AimsSeveral randomized trials of patients with carotid stenosis show increased adverse neurological events with stenting versus endarterectomy in the 30-day post-procedure. This study examines the incidence of new ischaemic lesions in patients treated in our centre using the new Roadsaver stent.Methods and resultsBetween September 2015 and January 2016, 23 consecutive patients (age 74.3 ± 7.3 years, 17.4 % female) underwent carotid artery stenting with the Roadsaver stent, a nitinol double-layer micromesh device. A distal protection device was used in all cases. Diffusion-weighted magnetic resonance imaging was performed 24 h before, and 24 h and 30 days after the procedure. The 24-h post-procedure imaging showed 15 new ipsilateral ischaemic lesions in 7 (30.4 %) patients: median volume 0.076 cm{sup 3} (interquartile range 0.065–0.146 cm{sup 3}). All lesions were asymptomatic. The 30-day imaging showed complete resolution of all lesions and no new ischaemic lesions. Follow-up clinical and ultrasound examinations at 30 days and 6 months recorded no adverse cardiac or cerebrovascular events.ConclusionsProtected stenting with micromesh Roadsaver stent showed good safety and efficacy in the treatment of carotid stenosis, with a low incidence of delayed embolic events and new ipsilateral ischaemic brain lesions. These preliminary results are encouraging, but need to be confirmed with larger populations.

  15. Incidence of New Ischaemic Brain Lesions After Carotid Artery Stenting with the Micromesh Roadsaver Carotid Artery Stent: A Prospective Single-Centre Study

    International Nuclear Information System (INIS)

    Ruffino, Maria Antonella; Faletti, Riccardo; Bergamasco, Laura; Fonio, Paolo; Righi, Dorico

    2016-01-01

    AimsSeveral randomized trials of patients with carotid stenosis show increased adverse neurological events with stenting versus endarterectomy in the 30-day post-procedure. This study examines the incidence of new ischaemic lesions in patients treated in our centre using the new Roadsaver stent.Methods and resultsBetween September 2015 and January 2016, 23 consecutive patients (age 74.3 ± 7.3 years, 17.4 % female) underwent carotid artery stenting with the Roadsaver stent, a nitinol double-layer micromesh device. A distal protection device was used in all cases. Diffusion-weighted magnetic resonance imaging was performed 24 h before, and 24 h and 30 days after the procedure. The 24-h post-procedure imaging showed 15 new ipsilateral ischaemic lesions in 7 (30.4 %) patients: median volume 0.076 cm"3 (interquartile range 0.065–0.146 cm"3). All lesions were asymptomatic. The 30-day imaging showed complete resolution of all lesions and no new ischaemic lesions. Follow-up clinical and ultrasound examinations at 30 days and 6 months recorded no adverse cardiac or cerebrovascular events.ConclusionsProtected stenting with micromesh Roadsaver stent showed good safety and efficacy in the treatment of carotid stenosis, with a low incidence of delayed embolic events and new ipsilateral ischaemic brain lesions. These preliminary results are encouraging, but need to be confirmed with larger populations.

  16. A new self-expandable aortic valved stent deployed above native leaflets for aortic insufficiency: an in vitro study.

    Science.gov (United States)

    Huang, H; Zhou, Y; Shao, J; Cai, J; Mei, Y; Wang, Y

    2012-12-01

    The aim of this paper was to develop a new self-expandable aortic valved stent following the shape of the sinus of Valsalva, which can be deployed above native leaflets for aortic regurgitation, and study it's effect on coronary artery flow when orthotopic implantation in and above native leaflets. New self-expandable aortic valved stent consist of nitinol stent and bovine pericardium, and was designed following the shape of the sinus of Valsalva, the bovine pericardium was tailed as native leaflet. Thirty-six swine hearts were divided into three equal groups of twelve. In Group A (N.=12), the new self-expandable aortic valved stents deployed in native leaflets. In Group B (N.=12), the new self-expandable aortic valved stents deployed above native leaflets. In Group C (N.=12), the cylinder-like valved stents deployed only in native leaflets. The measurements of each coronary flow rate and endoscopic inspections were repeated post-implantation. In Group A and C, valve implantation in native leaflets resulted in a significant decrease in both left and right coronary flows. In Group B, no significant change in either right or left coronary flow was found after new self-expandable aortic valved stent placement. Endoscopic inspections showed that in group A and C the native leaflets sandwiched between valved stent and aortic wall, whereas, in group B the native leaflets were under the artificial leaflets. Two kinds of stents deployed in native leaflets affect left and right coronary flows significantly. No significant effect was found when the new self-expandable aortic valved stent deployed above native leaflets. This new self-expandable aortic valved stent can be deployed above the native leaflets, which avoids the obstruction of native leaflets on coronary flow.

  17. Influence of a dexamethasone-eluting covered stent on tissue reaction: an experimental study in a canine bronchial model

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Ji Hoon; Song, Ho-Young; Choi, Gi Bok; Kim, Tae-Hyung; Suh, Ji-Yeon [University of Ulsan College of Medicine, Department of Radiology, Asan Medical Center, Seoul (Korea); Seo, Tae-Seok [Gachon Medical School, Department of Radiology, Gil Medical Center, Inchon (Korea); Yuk, Soon Hong [Hannam University, Department of Polymer Science and Engineering, College of Engineering, Daejeon (Korea); Kim, Young-Hwa [Soonchunhyang University Chonan Hospital, Department of Radiology, Chonan (Korea); Cho, Yong-Mee [University of Ulsan College of Medicine, Department of Pathology, Asan Medical Center, Seoul (Korea)

    2005-06-01

    This study was designed to evaluate the feasibility and efficacy of a dexamethasone (DXM)-eluting, covered, self-expanding metallic stent to reduce tissue reaction following stent placement in a canine bronchial model. We placed a DXM-eluting, polyurethane-covered, self-expanding metallic stent (drug stent, DS) and a polyurethane-covered, self-expanding metallic stent (control stent, CS) alternately in each left main bronchus and left lower lobe bronchus in 12 dogs. The stents were 20 mm in diameter and length when fully expanded. The dose of DXM was approximately 36.7 mg in each DS, but was absent in the CS. The dogs were euthanased 1 week (n=4), 2 weeks (n=4) or 4 weeks (n=4) after stent placement. Histologic findings, such as epithelial erosion/ulcer or granulation tissue thickness, were obtained from the mid-portion of the bronchus, where the stent had been placed, and evaluated between DS and CS. There were no procedure-related complications or malpositioning of any of the bronchial stents. Stent migration was detected in one dog just before euthanasia 1 week following stent placement. Stent patency was maintained until euthanasia in all dogs. Epithelial erosion/ulcer (%) was significantly less in the DS (mean{+-}standard deviation, 46.88{+-}23.75) than in the CS (73.75{+-}14.08) (P=0.026) for all time-points. There was a decrease in epithelial erosion/ulcer as the follow-up period increased in both DS and CS. The granulation tissue thickness (mm) was less in DS (2.63{+-}2.05) than in CS (3.49{+-}2.95), although the difference was not significant (P=0.751) for all time-points. There was a tendency toward an increase in granulation tissue thickness and chronic lymphocytic infiltration as the follow-up period increased in both DS and CS. In conclusion, DXM-eluting, covered, self-expanding metallic stent seems to be effective in reducing tissue reaction secondary to stent placement in a canine bronchial model. (orig.)

  18. Influence of a dexamethasone-eluting covered stent on tissue reaction: an experimental study in a canine bronchial model

    International Nuclear Information System (INIS)

    Shin, Ji Hoon; Song, Ho-Young; Choi, Gi Bok; Kim, Tae-Hyung; Suh, Ji-Yeon; Seo, Tae-Seok; Yuk, Soon Hong; Kim, Young-Hwa; Cho, Yong-Mee

    2005-01-01

    This study was designed to evaluate the feasibility and efficacy of a dexamethasone (DXM)-eluting, covered, self-expanding metallic stent to reduce tissue reaction following stent placement in a canine bronchial model. We placed a DXM-eluting, polyurethane-covered, self-expanding metallic stent (drug stent, DS) and a polyurethane-covered, self-expanding metallic stent (control stent, CS) alternately in each left main bronchus and left lower lobe bronchus in 12 dogs. The stents were 20 mm in diameter and length when fully expanded. The dose of DXM was approximately 36.7 mg in each DS, but was absent in the CS. The dogs were euthanased 1 week (n=4), 2 weeks (n=4) or 4 weeks (n=4) after stent placement. Histologic findings, such as epithelial erosion/ulcer or granulation tissue thickness, were obtained from the mid-portion of the bronchus, where the stent had been placed, and evaluated between DS and CS. There were no procedure-related complications or malpositioning of any of the bronchial stents. Stent migration was detected in one dog just before euthanasia 1 week following stent placement. Stent patency was maintained until euthanasia in all dogs. Epithelial erosion/ulcer (%) was significantly less in the DS (mean±standard deviation, 46.88±23.75) than in the CS (73.75±14.08) (P=0.026) for all time-points. There was a decrease in epithelial erosion/ulcer as the follow-up period increased in both DS and CS. The granulation tissue thickness (mm) was less in DS (2.63±2.05) than in CS (3.49±2.95), although the difference was not significant (P=0.751) for all time-points. There was a tendency toward an increase in granulation tissue thickness and chronic lymphocytic infiltration as the follow-up period increased in both DS and CS. In conclusion, DXM-eluting, covered, self-expanding metallic stent seems to be effective in reducing tissue reaction secondary to stent placement in a canine bronchial model. (orig.)

  19. Conformable covered versus uncovered self-expandable metallic stents for palliation of malignant gastroduodenal obstruction: a randomized prospective study.

    Science.gov (United States)

    Lim, Sun Gyo; Kim, Jin Hong; Lee, Kee Myung; Shin, Sung Jae; Kim, Chan Gyoo; Kim, Kyung Ho; Kim, Ho Gak; Yang, Chang Heon

    2014-07-01

    A conformable self-expandable metallic stent was developed to overcome the limitation of previous self-expandable metallic stents. The aim of this study was to evaluate outcomes after placement of conformable covered and uncovered self-expandable metallic stents for palliation of malignant gastroduodenal obstruction. A single-blind, randomized, parallel-group, prospective study were conducted in 4 medical centres between March 2009 and July 2012. 134 patients with unresectable malignant gastroduodenal obstruction were assigned to a covered double-layered (n=66) or uncovered unfixed-cell braided (n=68) stent placement group. Primary analysis was performed to compare re-intervention rates between two groups. 120 patients were analysed (59 in the covered group and 61 in the uncovered group). Overall rates of re-intervention were not significantly different between the two groups: 13/59 (22.0%) in the covered group vs. 13/61 (21.3%) in the uncovered group, p=0.999. Stent migration was more frequent in the covered group than in the uncovered group (p=0.003). The tumour ingrowth rate was higher in the uncovered group than in the covered group (p=0.016). The rates of re-intervention did not significantly differ between the two stents. Conformable covered double-layered and uncovered unfixed-cell braided stents were associated with different patterns of stent malfunction. Copyright © 2014 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

  20. Loupe-Assisted Vasovasostomy Using a Prolene Stent: A Simpler Vasectomy Reversal Technique

    Directory of Open Access Journals (Sweden)

    Jong Chul Jeon

    2017-08-01

    Full Text Available Purpose: Microsurgical vasovasostomy is associated with high patency and pregnancy rates, but is difficult and requires significant effort and time to learn. Therefore, we assessed a simplified loupe-assisted vasovasostomy method using a Prolene stent. Materials and Methods: The medical records of 82 patients who underwent loupe-assisted vasovasostomy with a Prolene stent by a single surgeon between January 2004 and December 2015 were reviewed. The association between the vasal obstructive interval (VOI and the success rate was evaluated. Results: The average age at the time of vasovasostomy was 39.8 years (range, 29∼57 years. The mean VOI was 6.6 years (range, 1∼19 years. The mean operation time was 87.0 minutes (range, 55.0∼140.0 minutes. The overall patency and natural pregnancy rates were 90.2% and 45.1%, respectively. The success rate decreased as time after vasectomy increased (odds ratio, 0.869; 95% confidence interval, 0.760∼0.993; p=0.039. The cases were divided into 2 groups according to the mean VOI: group A (>7 years and group B (≤7 years, with 31 cases (37.8% and 51 cases (62.2%, respectively. The patency and pregnancy rates of group A were 80.6% and 51.6%, respectively, while those of group B were 96.1% and 41.2%, respectively. Conclusions: Loupe-assisted vasovasostomy using a Prolene stent is a safe and effective method.

  1. High-definition computed tomography for coronary artery stents imaging: Initial evaluation of the optimal reconstruction algorithm.

    Science.gov (United States)

    Cui, Xiaoming; Li, Tao; Li, Xin; Zhou, Weihua

    2015-05-01

    The aim of this study was to evaluate the in vivo performance of four image reconstruction algorithms in a high-definition CT (HDCT) scanner with improved spatial resolution for the evaluation of coronary artery stents and intrastent lumina. Thirty-nine consecutive patients with a total of 71 implanted coronary stents underwent coronary CT angiography (CCTA) on a HDCT (Discovery CT 750 HD; GE Healthcare) with the high-resolution scanning mode. Four different reconstruction algorithms (HD-stand, HD-detail; HD-stand-plus; HD-detail-plus) were applied to reconstruct the stented coronary arteries. Image quality for stent characterization was assessed. Image noise and intrastent luminal diameter were measured. The relationship between the measurement of inner stent diameter (ISD) and the true stent diameter (TSD) and stent type were analysed. The stent-dedicated kernel (HD-detail) offered the highest percentage (53.5%) of good image quality for stent characterization and the highest ratio (68.0±8.4%) of visible stent lumen/true stent lumen for luminal diameter measurement at the expense of an increased overall image noise. The Pearson correlation coefficient between the ISD and TSD measurement and spearman correlation coefficient between the ISD measurement and stent type were 0.83 and 0.48, respectively. Compared with standard reconstruction algorithms, high-definition CT imaging technique with dedicated high-resolution reconstruction algorithm provides more accurate stent characterization and intrastent luminal diameter measurement. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  2. Stenting or not prior to extracorporeal shockwave lithotripsy for ureteral stones? Results of a prospective randomized study.

    Science.gov (United States)

    Sfoungaristos, Stavros; Polimeros, Nikolaos; Kavouras, Adamantios; Perimenis, Petros

    2012-06-01

    To determine the need for pre-treatment stenting in patients undergoing extracorporeal shockwave lithotripsy (ESWL) for ureteral stones sized 4-10 mm. A prospective randomized study was conducted between September 2009 and March 2011. Included 156 patients randomized in stented and non-stented groups and underwent a maximum of 3 ESWL sessions. Radiographic follow-up was used to assess the stone fragmentation and clearance. Results were compared in terms of stone-free rates, post-treatment morbidity and complications. Overall efficacy was 76.9%. Stone-free rates were statistically significantly lower (P = 0.026) in the stented group (68.6%) compared to the non-stented ones (83.7%). Furthermore, stenting was significantly correlated with post-treatment lower urinary tract symptoms (P ≤ 0.001), need for more ESWL sessions (P = 0.019) and possibility for operation due to ESWL failure (P = 0.026). A multivariate analysis was conducted to identify the parameters which may predict complete stone removal after ESWL. Stone size (P = 0.026), stone location (P = 0.011) and stenting (P = 0.007) were the most significant factors. ESWL is an efficient and safe treatment for 4- to 10-mm ureteral stones. Pre-treatment stenting is limiting stone-free rates and is significantly influencing post-ESWL morbidity and quality of life in a negative manner, while it contributes minimally to the prophylaxis of complications.

  3. Animal experimental studies on the influence of flow restriction on thrombogenicity of the Palmaz stent via 111indium marked thrombocytes

    International Nuclear Information System (INIS)

    Noeldge, G.; Siegerstetter, V.; Richter, G.M.; Garcia, O.; Palmaz, J.C.

    1990-01-01

    The purpose of this experimental study in dogs is to evaluate the influence of restricted flow on the thrombogenicity of balloon-expandable intravascular stents (Palmaz type). We implanted 24 Palmaz stents in the femoral artery of mongrel dogs. 12 dogs experienced a 75% flow restriction by means of an artificial stenosis distal to the start in the outflow tract. We used 111 In labelled thrombocytes as a marker for thrombus detection within the stent. The results presented demonstrate that there is no considerable risk of thrombus formation if the stent is implanted into vessels with good outflow tracts and therefore high blood flow velocities within the stent. Under conditions of highly impaired flow, a 68% rate of stent occlusion occur if no anticoagulation therapy is performed. After i.v. administration of 100 IU/kg body weight of heparin the occlusion rade drops to zero. It can be concluded that even under low-flow conditions as a result of a restricted outflow tract situation the Palmaz stent can be implanted without any risk of stent occlusion as long a sufficient anticoagulation protocol is maintained. (orig.) [de

  4. Pilot study of a novel, large-bore, fully covered self-expandable metallic stent for unresectable distal biliary malignancies.

    Science.gov (United States)

    Mukai, Tsuyoshi; Yasuda, Ichiro; Isayama, Hiroyuki; Iwashita, Takuji; Itoi, Takao; Kawakami, Hiroshi; Kogure, Hirofumi; Nakai, Yousuke

    2016-09-01

    In patients with unresectable malignant distal biliary obstruction, covered self-expandable metallic stents (CSEMS) may remain patent longer than uncovered self-expandable metallic stents as a result of tumor ingrowth prevention. One main cause of recurrent biliary obstruction (RBO) in CSEMS is sludge formation, which can be prevented using a large-bore stent. Therefore, we developed a novel, 12-mm diameter fully covered SEMS (FCSEMS) and investigated its clinical safety, efficacy, and rate of adverse events. This prospective, multicenter pilot study, which ran between June 2011 and November 2012, included 38 consecutive patients with unresectable malignant distal biliary obstruction. All patients underwent endoscopic insertion of our novel stent. Primary endpoint was non-RBO rate 6 months after placement. Technical and functional success rates of the procedures were 100%. Six-month non-RBO rate was 50%, and median time to RBO was 184 days. Median survival time was 241 days. Twelve patients died within 6 months after stent placement without RBO. RBO was observed in 10 patients (26%), with seven experiencing stent occlusion and three experiencing stent migration. Adverse events other than RBO (at Stent removal for reintervention was successfully completed in eight patients. Our novel FCSEMS may be safe and effective for managing malignant distal obstruction with an acceptable incidence of adverse events. © 2016 Japan Gastroenterological Endoscopy Society.

  5. Endoscopic management of unresectable malignant gastroduodenal obstruction with a nitinol uncovered metal stent: A prospective Japanese multicenter study

    Science.gov (United States)

    Sasaki, Reina; Sakai, Yuji; Tsuyuguchi, Toshio; Nishikawa, Takao; Fujimoto, Tatsuya; Mikami, Shigeru; Sugiyama, Harutoshi; Yokosuka, Osamu

    2016-01-01

    AIM: To determine the safety and efficacy of endoscopic duodenal stent placement in patients with malignant gastric outlet obstruction. METHODS: This prospective, observational, multicenter study included 39 consecutive patients with malignant gastric outlet obstruction. All patients underwent endoscopic placement of a nitinol, uncovered, self-expandable metal stent. The primary outcome was clinical success at 2 wk after stent placement that was defined as improvement in the Gastric Outlet Obstruction Scoring System score relative to the baseline. RESULTS: Technical success was achieved in all duodenal stent procedures. Procedure-related complications occurred in 4 patients (10.3%) in the form of mild pneumonitis. No other morbidities or mortalities were observed. The clinical success rate was 92.3%. The mean survival period after stent placement was 103 d. The mean period of stent patency was 149 d and the patency remained acceptable for the survival period. Stent dysfunction occurred in 3 patients (7.7%) on account of tumor growth. CONCLUSION: Endoscopic management using duodenal stents for patients with incurable malignant gastric outlet obstruction is safe and improved patients’ quality of life. PMID:27076769

  6. Auxetic coronary stent endoprosthesis

    DEFF Research Database (Denmark)

    Amin, Faisal; Ali, Murtaza Najabat; Ansari, Umar

    2014-01-01

    BACKGROUND: Cardiovascular heart disease is one of the leading health issues in the present era and requires considerable health care resources to prevent it. The present study was focused on the development of a new coronary stent based on novel auxetic geometry which enables the stent to exhibit...... a negative Poisson's ratio. Commercially available coronary stents have isotropic properties, whereas the vascular system of the body shows anisotropic characteristics. This results in a mismatch between anisotropic-isotropic properties of the stent and arterial wall, and this in turn is not favorable...... for mechanical adhesion of the commercially available coronary stents with the arterial wall. It is believed that an auxetic coronary stent with inherent anisotropic mechanical properties and negative Poisson's ratio will have good mechanical adhesion with the arterial wall. METHODS: The auxetic design...

  7. Development of a New Hanging-Type Esophageal Stent for Preventing Migration: A Preliminary Study in an Animal Model of Esophagotracheal Fistula

    Energy Technology Data Exchange (ETDEWEB)

    Endo, Masayuki, E-mail: masay010@yahoo.co.jp; Kaminou, Toshio, E-mail: kaminout@med.tottori-u.ac.jp; Ohuchi, Yasufumi, E-mail: oyasu@med.tottori-u.ac.jp [Tottori University, Department of Radiology, Faculty of Medicine (Japan); Sugiura, Kimihiko, E-mail: kimihikosugiura@gmail.com [Yonago Medical Center, Department of Radiology (Japan); Yata, Shinsaku, E-mail: yata-s@med.tottori-u.ac.jp; Adachi, Akira, E-mail: july1st@med.tottori-u.ac.jp; Kawai, Tsuyoshi, E-mail: prgr-xxio@kuc.biglobe.ne.jp; Takasugi, Syohei, E-mail: stakasugi@med.tottori-u.ac.jp; Yamamoto, Shuichi, E-mail: yamamotoshu@med.tottori-u.ac.jp; Matsumoto, Kensuke, E-mail: matsumoto-k@v103.vaio.ne.jp [Tottori University, Department of Radiology, Faculty of Medicine (Japan); Hashimoto, Masayuki, E-mail: hashimotom@pref.tottori.jp [Tottori Prefectural Kosei Hospital, Department of Radiology (Japan); Ihaya, Takashi, E-mail: iahaya@orange.ocn.ne.jp [Sanin Rosai Hospital, Department of Radiology (Japan); Ogawa, Toshihide, E-mail: ogawa@med.tottori-u.ac.jp [Tottori University, Department of Radiology, Faculty of Medicine (Japan)

    2012-10-15

    Purpose: Covered, self-expandable metallic stents (SEMS) have been enthusiastically adopted for the treatment of esophagotracheal fistula, but problems with stent migration have yet to be resolved. To overcome this problem, we have developed a new hanging-type esophageal stent designed to prevent migration, and we conducted an animal study to assess the efficacy of our method. Methods: A total of six female pigs were used in this study. The main characteristic of our stent was the presence of a string tied to the proximal edge of the stent for fixation under the skin of the neck. The first experiment was performed to confirm technical feasibility in three pigs with esophagotracheal fistula. The second experiment was performed to evaluate stent migration and esophagotracheal fistula in three pigs. Results: Creation of the esophagotracheal fistula and stent placement were technically successful in all pigs. In the first experiment, esophagotracheal fistula was sealed by stent placement. In the second experiment, no stent migration was seen 11 or 12 days after stent placement. Gross findings showed no fistulas on the esophageal or tracheal wall. Conclusions: Our new hanging-type esophageal stent seems to offer a feasible method for preventing stent migration.

  8. Development of a New Hanging-Type Esophageal Stent for Preventing Migration: A Preliminary Study in an Animal Model of Esophagotracheal Fistula

    International Nuclear Information System (INIS)

    Endo, Masayuki; Kaminou, Toshio; Ohuchi, Yasufumi; Sugiura, Kimihiko; Yata, Shinsaku; Adachi, Akira; Kawai, Tsuyoshi; Takasugi, Syohei; Yamamoto, Shuichi; Matsumoto, Kensuke; Hashimoto, Masayuki; Ihaya, Takashi; Ogawa, Toshihide

    2012-01-01

    Purpose: Covered, self-expandable metallic stents (SEMS) have been enthusiastically adopted for the treatment of esophagotracheal fistula, but problems with stent migration have yet to be resolved. To overcome this problem, we have developed a new hanging-type esophageal stent designed to prevent migration, and we conducted an animal study to assess the efficacy of our method. Methods: A total of six female pigs were used in this study. The main characteristic of our stent was the presence of a string tied to the proximal edge of the stent for fixation under the skin of the neck. The first experiment was performed to confirm technical feasibility in three pigs with esophagotracheal fistula. The second experiment was performed to evaluate stent migration and esophagotracheal fistula in three pigs. Results: Creation of the esophagotracheal fistula and stent placement were technically successful in all pigs. In the first experiment, esophagotracheal fistula was sealed by stent placement. In the second experiment, no stent migration was seen 11 or 12 days after stent placement. Gross findings showed no fistulas on the esophageal or tracheal wall. Conclusions: Our new hanging-type esophageal stent seems to offer a feasible method for preventing stent migration.

  9. Colonic stenting as bridge to surgery versus emergency surgery for management of acute left-sided malignant colonic obstruction: a multicenter randomized trial (Stent-in 2 study

    Directory of Open Access Journals (Sweden)

    Scholten Pieter

    2007-07-01

    Full Text Available Abstract Background Acute left-sided colonic obstruction is most often caused by malignancy and the surgical treatment is associated with a high mortality and morbidity rate. Moreover, these operated patients end up with a temporary or permanent stoma. Initial insertion of an enteral stent to decompress the obstructed colon, allowing for surgery to be performed electively, is gaining popularity. In uncontrolled studies stent placement before elective surgery has been suggested to decrease mortality, morbidity and number of colostomies. However stent perforation can lead to peritoneal tumor spill, changing a potentially curable disease in an incurable one. Therefore it is of paramount importance to compare the outcomes of colonic stenting followed by elective surgery with emergency surgery for the management of acute left-sided malignant colonic obstruction in a randomized multicenter fashion. Methods/design Patients with acute left-sided malignant colonic obstruction eligible for this study will be randomized to either emergency surgery (current standard treatment or colonic stenting as bridge to elective surgery. Outcome measurements are effectiveness and costs of both strategies. Effectiveness will be evaluated in terms of quality of life, morbidity and mortality. Quality of life will be measured with standardized questionnaires (EORTC QLQ-C30, EORTC QLQ-CR38, EQ-5D and EQ-VAS. Morbidity is defined as every event leading to hospital admission or prolonging hospital stay. Mortality will be analyzed as total mortality as well as procedure-related mortality. The total costs of treatment will be evaluated by counting volumes and calculating unit prices. Including 120 patients on a 1:1 basis will have 80% power to detect an effect size of 0.5 on the EORTC QLQ-C30 global health scale, using a two group t-test with a 0.05 two-sided significance level. Differences in quality of life and morbidity will be analyzed using mixed-models repeated measures

  10. Numerical investigation of influence of number of stent cells and ...

    Indian Academy of Sciences (India)

    Chandrakantha Bekal

    2018-05-29

    May 29, 2018 ... namics behaviour through computational analysis based on finite element and finite volume techniques. The study compares ... Indian Academy of Sciences ... ded stent geometry is subjected to blood flow simulation to.

  11. Transcatheter aortic value implantation with self-expandable nitinol valved stent: an experimental study in sheep

    International Nuclear Information System (INIS)

    Jiang Haibin; Huang Xinmiao; Bai Yuan

    2011-01-01

    Objective: to determine the feasibility and safety of transcatheter aortic valve implantation with domestic self-expandable nitinol valved stent in experimental sheep. Methods: A fresh pig pericardium was cross-linked with a 0.6% glutaraldehyde solution for 36 hours and then sutured on a nitinol self-expandable stent. Ten healthy sheep of (46.00±2.60) kg body weight were chosen for the study. Under general anesthesia, the device was delivered through catheter into the native aortic valve of the sheep via the femoral artery or abdominal aorta. The animals were followed up for three months. Results: Six devices were successfully delivered at the desired position in six sheep with no occurrence of complications. Angiographic and hemodynamic studies confirmed that the stents were fixed at correct position with competent valve function immediately and 90 days after the procedure. Technical failure or fatal complications occurred in the remaining four sheep. Conclusion: Implantation of a domestic nitinol self-expandable stent at the aortic valve position through a transcatheter approach is feasible in experimental sheep. (authors)

  12. A newly-designed temporary cardia stent for the treatment of achalasia:an experimental study in canine models

    International Nuclear Information System (INIS)

    Kuang Xiaochun; Cheng Yingsheng; Zhu Yueqi; Li Feng; Wang Weiguo

    2010-01-01

    Objective: To assess the efficacy and safety of a newly-designed temporary covered cardia stent for the treatment of achalasia in canine models and to investigate the histopathological changes at different points of follow-up time after the stent was removed. Methods: The canine achalasia model was created by injecting benzyl-dimethyl-tetradecyl ammonium chloride (BAC) circumferentially into the lower esophageal sphincter (LES) of the dogs. Twenty-four dogs with achalasia were randomly and equally divided into two groups with 12 dogs in each group: control group (using routine esophageal stents) and study group (using newly-designed temporary covered cardia stents). Under fluoroscopic guidance stents were implanted in the esophagus and were taken away from the esophagus 4 days after stent insertion in experimental dogs of both groups. LES pressures and timed barium esophagography (TBE) were performed in all dogs before and immediately after the stenting procedure, as well as at one week, 3 and 6 months after the stent was removed. Every three dogs were sacrificed each time at one week, 3 and 6 months after the stent was removed. The esophageal cardia was excised and sent for pathological examination. Results: All animals well tolerated the stent insertion / removal and the follow-up procedures. No severe complications such as esophageal perforation occurred. Comparison between two groups showed that stent migration occurrence was much lower in study group (n = 1) than that in control group (n = 5). The reduction of LES pressures in study group was more significant in comparison with control group (at 6-month follow-up, P = 0.027). The difference in barium column product (height x width) between 0-min and 5-min TBE was statistically significant in study group (at 3-month follow-up, P = 0.009). Integrated analysis of multi-comparison for LES pressures among subgroups of each group revealed that the dogs in study group exhibited better outcomes than the dogs in

  13. Intravascular ultrasound assessment of minimumlumen area and intimal hyperplasia in in-stent restenosis after drug-eluting or bare-metal stent implantation. The Nordic Intravascular Ultrasound Study (NIVUS)

    DEFF Research Database (Denmark)

    Jensen, Lisette Okkels; Vikman, Saila; Antonsen, Lisbeth

    2017-01-01

    presenting with a DES or bare-metal stent (BMS) in-stent restenosis. Methods: The ``Nordic Intravascular Ultrasound Study (NIVUS)'' study was conducted in Nordic and Baltic countries as a prospective multicenter registry. Two hundred nine patients (DES n = 121 and BMS n = 88) with instent restenosis were...

  14. Hybrid endovascular stent-grafting technique for patent ductus arteriosus in an adult.

    Science.gov (United States)

    Kainuma, S; Kuratani, T; Sawa, Y

    2011-09-01

    A 51-year-old man was referred to our institution for patent ductus arteriosus (PDA) complicated by left ventricular dysfunction and pulmonary hypertension. Surgical closure of a PDA is usually carried out via a small posterior thoracotomy. However, thoracoscopic procedures are probably not appropriate in adults because of the frequency of calcification and the greater risk of rupture while ligating the ductus. To minimize surgical trauma, we used hybrid endovascular stent grafting combined with revascularization of the left subclavian artery, which enabled us to eliminate shunt flow to the pulmonary artery. At 11-month follow-up, the patient was asymptomatic and showed no complications. © Georg Thieme Verlag KG Stuttgart · New York.

  15. Drug-eluting stents to prevent stent thrombosis and restenosis.

    Science.gov (United States)

    Im, Eui; Hong, Myeong-Ki

    2016-01-01

    Although first-generation drug-eluting stents (DES) have significantly reduced the risk of in-stent restenosis, they have also increased the long-term risk of stent thrombosis. This safety concern directly triggered the development of new generation DES, with innovations in stent platforms, polymers, and anti-proliferative drugs. Stent platform materials have evolved from stainless steel to cobalt or platinum-chromium alloys with an improved strut design. Drug-carrying polymers have become biocompatible or biodegradable and even polymer-free DES were introduced. New limus-family drugs (such as everolimus, zotarolimus or biolimus) were adopted to enhance stent performances. As a result, these new DES demonstrated superior vascular healing responses on intracoronary imaging studies and lower stent thrombotic events in actual patients. Recently, fully-bioresorbable stents (scaffolds) have been introduced, and expanding their applications. In this article, the important concepts and clinical results of new generation DES and bioresorbable scaffolds are described.

  16. The application of DynaCT in performing the placement of intracranial stent

    International Nuclear Information System (INIS)

    Shen Hui; Wang Yongchun; Wang Minjie; Ding Hailing; Qin Yashan; Mao Yaqin; Li Songhua; Mao Yanjun; Hao Qiang

    2011-01-01

    Objective: To evaluate the clinical application of DynaCT technique in performing intracranial stent implantation. Methods: Thirty-nine patients who were planed to receive intracranial stent implantation were involved in this study. During the procedure DynaCT scanning was employed to monitor the real-time situation of stent implantation. Results: A total of 47 stents were implanted in intracranial vessels in the 39 patients. By using conventional angiography during operation the position of these stents was observed and was assured to be in the proper position. The adherence of these stents to the vascular wall was demonstrated with DynaCT multi-planar reconstruction images and the stent adherence in good condition was ensured. Conclusion: DynaCT applied during and after intracranial stent implantation is very helpful for displaying the contours of the stents as well as the vascular lumen and for providing a detail picture of the relationship between the stent and the surrounding anatomy. Therefore, DynaCT scanning is of great clinical significance for performing the intracranial stent implantation. (authors)

  17. Mechanisms of biliary stent clogging: confocal laser scanning and scanning electron microscopy.

    Science.gov (United States)

    van Berkel, A M; van Marle, J; Groen, A K; Bruno, M J

    2005-08-01

    Endoscopic insertion of plastic biliary endoprostheses is a well-established treatment for obstructive jaundice. The major limitation of this technique is late stent occlusion. In order to compare events involved in biliary stent clogging and identify the distribution of bacteria in unblocked stents, confocal laser scanning (CLS) and scanning electron microscopy (SEM) were carried out on two different stent materials - polyethylene (PE) and hydrophilic polymer-coated polyurethane (HCPC). Ten consecutive patients with postoperative benign biliary strictures were included in the study. Two 10-Fr stents 9 cm in length, one made of PE and the other of HCPC, were inserted. The stents were electively exchanged after 3 months and examined using CLS and SEM. No differences were seen between the two types of stent. The inner stent surface was covered with a uniform amorphous layer. On top of this layer, a biofilm of living and dead bacteria was found, which in most cases was unstructured. The lumen was filled with free-floating colonies of bacteria and crystals, surrounded by mobile laminar structures of mucus. An open network of large dietary fibers was seen in all of the stents. The same clogging events occurred in both PE and HCPC stents. The most remarkable observation was the identification of networks of large dietary fibers, resulting from duodenal reflux, acting as a filter. The build-up of this intraluminal framework of dietary fibers appears to be a major factor contributing to the multifactorial process of stent clogging.

  18. Nasolacrimal Stenting: Toward Improving Outcomes with a Simple Modification of the Song Stent

    International Nuclear Information System (INIS)

    Lanciego, Carlos; Miguel, Silvia De; Padilla, Manuel; Perea, Miguel; Rodriguez-Merlo, Rufo; Garcia-Garcia, Lorenzo

    2006-01-01

    The purpose of this study was to evaluate, in a prospective, single-center study, the effectiveness of Song's polyurethane stents, modified 'in-house,' in the percutaneous management of epiphora. Patients (n = 170; age range 18-83, mean = 64; 50 male, 120 female) with severe epiphora had the modified stents inserted (183 eyes/195 stents) to treat unilateral/bilateral and complete/partial obstruction of the nasolacrimal system. The etiology of the obstruction was idiopathic in 119 cases (61%) and chronic dacryocystitis in 76 (39%). The set designed by Song was used in all patients but modified by us such that the extreme end is cone-shaped. The original technique was slightly modified by us and the procedure was conducted on an outpatient basis. The initial technical success rate of stent placement was 97%. Resolution of epiphora was complete in 180 eyes and partial in 3. On follow-up (mean = 18 months; range: 2 days to 24 months), 165 of 195 stents (85%) remained patent. Primary patency rates at follow-up were 86%, 84%, 84%, and 79% in the first 6 months, second and third 6 months, and the present (24 months), respectively. Stents became obstructed in 30 patients, but all but 2 were easily withdrawn and 20 of these patients remained asymptomatic for a mean of 14 months (secondary patency of 67%). Following stent removal, the withdrawn stent was replaced with a new stent in the same intervention on 14 occasions. In another six cases, patency was re-established without the need of a second stent. The procedure is simple and safe, both in stent insertion as well as in mechanical de-blocking and withdrawal when occluded. Success was >80 % in the short term (1-year follow-up). Stenting failure does not preclude other treatment because with the modification that we had introduced, the extreme end of the stent becomes more accessible to mechanical de-blocking, withdrawal, and relocation. The levels of primary and secondary patencies are promising and warrant more

  19. Treating Epiphora in Adults With the Wilhelm Plastic Nasolacrimal Stent: Mid-Term Results of a Prospective Study

    International Nuclear Information System (INIS)

    Ciampi, Juan J.; Lanciego, Carlos; Navarro, Sofia; Cuena, Rafael; Velasco, Javier; Perea, Miguel; García-García, Lorenzo

    2011-01-01

    The objective of the present study was to evaluate, in a prospective, single-center study, the effectiveness of the Wilhelm-type stent used in interventional radiology for the management of epiphora. Patients (n = 104; mean age 64 [range 25–88]; 33 male and 71 female) with severe epiphora had the stents inserted (135 stents in 115 eyes) to treat obstruction of the nasolacrimal system. The etiology of the obstruction was idiopathic in 83 cases, chronic dacryocystitis in 31, cases and postsurgical status in 1 case. The overall technical success rate of stent placement was near 94%. Resolution of epiphora was complete in 105 cases and partial in 3 cases. During a mean 13-month follow-up (range 1 week to 28 months), the median duration of primary patency was 11 months, and the percentage of patency at 6 months was 60.8%, at 1 year was 39.6%, and at 2 years was 25%. Stents malfunctioned in 54 cases, and all were easily withdrawn except in 1 case. Of these 27 cases, patency recovered spontaneously in 9 and by way of a second stent in 18. Secondary patency was 50%. Factors presdisposing to lower primary patency are inflammatory etiology and location of the obstruction. The benefit of stent deployment is clear with respect to the resolution of epiphora in candidate patients for percutaneous treatment. Technical and/or design improvements would be welcomed.

  20. Radial force measurement of endovascular stents: Influence of stent design and diameter.

    Science.gov (United States)

    Matsumoto, Takuya; Matsubara, Yutaka; Aoyagi, Yukihiko; Matsuda, Daisuke; Okadome, Jun; Morisaki, Koichi; Inoue, Kentarou; Tanaka, Shinichi; Ohkusa, Tomoko; Maehara, Yoshihiko

    2016-04-01

    Angioplasty and endovascular stent placement is used in case to rescue the coverage of main branches to supply blood to brain from aortic arch in thoracic endovascular aortic repair. This study assessed mechanical properties, especially differences in radial force, of different endovascular and thoracic stents. We analyzed the radial force of three stent models (Epic, E-Luminexx and SMART) stents using radial force-tester method in single or overlapping conditions. We also analyzed radial force in three thoracic stents using Mylar film testing method: conformable Gore-TAG, Relay, and Valiant Thoracic Stent Graft. Overlapping SMART stents had greater radial force than overlapping Epic or Luminexx stents (P stents was greater than that of all three endovascular stents (P stents, site of deployment, and layer characteristics. In clinical settings, an understanding of the mechanical characteristics, including radial force, is important in choosing a stent for each patient. © The Author(s) 2015.

  1. Biocompatibility of a new device of self-expandable covered and non-covered tracheal stent: comparative study in rats

    Directory of Open Access Journals (Sweden)

    Olavo Ribeiro Rodrigues

    2013-01-01

    Full Text Available PURPOSE: To investigate the compatibility of a new model of self-expandable tracheal stent in rats. METHODS: A new device of polyurethane covered and non - covered stent was placed in the trachea of Wistar rats. Animals were distributed in two groups: the polyurethane covered and non-covered group. Macroscopic parameters included position within the tracheal lumen, adherence to the mucosa, degree of dilatation, permeability and internal diameter. Microscopic findings evaluated were: incorporation, inflammatory activity, granulation tissue and epithelial revetment injuries. The observation follow-up was six weeks. All parameters were quantified based on determined score values. Incorporation of the stents was evaluated based on the observation if the stent was fixed into the trachea or if it could be removed. Degree of dilatation was performed by external diameter measurements. Granulation tissue was evaluated by measurements of height of the tissue growing into the tracheal lumen. RESULTS: 100% of non-covered stents had total attachment to mucosa and 100% of polyurethane covered type had adherence only. Regarding dilatation, granulation tissue, inflammatory activity and internal diameter measurements, there were no significant differences between the groups. Pathological tracheal wall injuries were present in both groups. CONCLUSION: Both models of stent demonstrated biocompatibility with the trachea. Rats are suitable for an experimental model of tracheal stent study.

  2. Serial Versus Direct Dilation of Small Diameter Stents Results in a More Predictable and Complete Intentional Transcatheter Stent Fracture: A PICES Bench Testing Study.

    Science.gov (United States)

    Crystal, Matthew A; Morgan, Gareth J; Danon, Saar; Gray, Robert G; Gruenstein, Daniel H; Gordon, Brent M; Goldstein, Bryan H

    2018-01-01

    Balloon-expandable stents, implanted in infants and children with congenital heart disease (CHD), often require redilation to match somatic growth. Small diameter stents may eventually require longitudinal surgical transection to prevent iatrogenic vascular stenosis. Intentional transcatheter stent fracture (TSF) is an emerging alternative approach to stent transection, but little is known about the optimal stent substrate and best protocol to improve the likelihood of successful TSF. Bench testing was performed with a stent dilation protocol. After recording baseline characteristics, stents were serially or directly dilated using ultra-high-pressure balloons (UHPB) until fracture occurred or further stent dilation was not possible. Stent characteristics recorded were as follows: cell design, metallurgy, mechanism, and uniformity of fracture. Stents tested included bare-metal coronary stents, premounted small diameter stents, and ePTFE-covered small diameter premounted stents. Ninety-four stents representing 9 distinct models were maximally dilated, with 80 (85%) demonstrating evidence of fracture. Comprehensive fracture details were recorded in 64 stents: linear and complete in 34/64 stents (53.1%), linear and incomplete in 9/64 stents (14.1%), transverse/complex and complete in 6/64 stents (9.4%), and transverse/complex and incomplete in 15/64 stents (23.4%). Stent fracture was not accomplished in some stent models secondary to significant shortening, i.e., "napkin-ring" formation. Serial dilation resulted in evidence of fracture in 62/67 (92.5%) stents compared with 18/27 (66.7%) stents in the direct dilation group (p = 0.003). Intentional TSF is feasible in an ex vivo model. Serial dilation more reliably expanded the stent and allowed for ultimate stent fracture, whereas direct large diameter dilation of stents was more likely to generate a "napkin-ring" configuration, which may be more resistant to fracture. In vivo animal and human testing is necessary to

  3. Stented Vessels: A Challenge for Histological Preparation and Microscopy

    Directory of Open Access Journals (Sweden)

    Andrea Nolte

    2013-06-01

    Full Text Available Objective: The first procedure to treat blocked coronary arteries was coronary artery bypass graft surgery. In 1977, Andreas Gruntzig introduced percutaneous transluminal coronary angioplasty (PTCA. Today, several stent systems exist ranging from bare metal stents to various drug-eluting stents. Unfortunately, our understanding of the arterial reaction to stent implantation is incomplete – primarily due to technical limitations in the histological study of stented vascular tissue. Methods: In our study, we examined different histological preparation methods based on the embedding material methacrylate. The procedure of embedding and sectioning stented porcine arteries was optimized for the specific requirements, like histochemistry, immunohistochemistry or pre-stained fluorescence. Furthermore, we used a microscopical technique described as fluorescence intensity decay shape analysis microscopy (FIDSAM to eliminate auto-fluorescence from fluorescently labeled tissue. Results: The sections were suitable for histochemical and immunohistochemical staining. Additionally, pre-labeled fluorescence in the porcine tissue was not lost by the embedding process. The evaluation of arterial cross sections with FIDSAM technology gave new, very important insights into the examination possibilities of fluorescently labeled tissue. Conclusions: Future studies of the vascular response to a variety of new stent materials will provide important clues to the pathogenesis resulting in restenosis and occlusion of stents. [J Interdiscipl Histopathol 2013; 1(3.000: 104-112

  4. Feasibility study using a Ni-Ti stent and electronic portal imaging to localize the prostate during radiotherapy

    International Nuclear Information System (INIS)

    Carl, Jesper; Lund, Bente; Larsen, Erik Hoejkjaer; Nielsen, Jane

    2006-01-01

    Background and purpose: A new method for localization of the prostate during external beam radiotherapy is presented. The method is based on insertion of a thermo-expandable Ni-Ti stent. The stent is originally developed for treatment of bladder outlet obstruction caused by benign hyperplasia. The radiological properties of the stent are used for precise prostate localization during treatment using electronic portal images. Patients and methods: Patients referred for intended curative radiotherapy and having a length of their prostatic urethra in the range from 25 to 65 mm were included. Pairs of isocentric orthogonal portal images were used to determine the 3D position at eight different treatment sessions for each patient. Results: Fourteen patients were enrolled in the study. The data obtained demonstrated that the stent position was representative of the prostate location. The stent may also improve delineation of the prostate GTV, and prevent obstruction of bladder outlet during treatment. Precision in localization of the stent was less than 1 mm. Random errors in stent position were left-right 1.6 mm, cranial-caudal 2.2 mm and anterior-posterior 3.2 mm. In four of 14 patients a dislocation of the stent to the bladder occurred. Dislocation only occurred in patients with length of prostatic urethra less than 40 mm. Conclusions: A new method for radiological high precision localization of the prostate during radiotherapy is presented. The method is based on insertion of a standard Ni-Ti thermo-expandable stent, designed for treatment of benign prostate hyperplasia

  5. Preoperative Belladonna and Opium Suppository for Ureteral Stent Pain: A Randomized, Double-blinded, Placebo-controlled Study.

    Science.gov (United States)

    Lee, Franklin C; Holt, Sarah K; Hsi, Ryan S; Haynes, Brandon M; Harper, Jonathan D

    2017-02-01

    To investigate whether the use of a belladonna and opium (B&O) rectal suppository administered immediately before ureteroscopy (URS) and stent placement could reduce stent-related discomfort. A randomized, double-blinded, placebo-controlled study was performed from August 2013 to December 2014. Seventy-one subjects were enrolled and randomized to receive a B&O (15 mg/30 mg) or a placebo suppository after induction of general anesthesia immediately before URS and stent placement. Baseline urinary symptoms were assessed using the American Urological Association Symptom Score (AUASS). The Ureteral Stent Symptom Questionnaire and AUASS were completed on postoperative days (POD) 1, 3, and after stent removal. Analgesic use intraoperatively, in the recovery unit, and at home was recorded. Of the 71 subjects, 65 had treatment for ureteral (41%) and renal (61%) calculi, 4 for renal urothelial carcinoma, and 2 were excluded for no stent placed. By POD3, the B&O group reported a higher mean global quality of life (QOL) score (P = .04), a better mean quality of work score (P = .05), and less pain with urination (P = .03). The B&O group reported an improved AUASS QOL when comparing POD1 with post-stent removal (P = .04). There was no difference in analgesic use among groups (P = .67). There were no episodes of urinary retention. Age was associated with unplanned emergency visits (P <.00) and "high-pain" measure (P = .02) CONCLUSION: B&O suppository administered preoperatively improved QOL measures and reduced urinary-related pain after URS with stent. Younger age was associated with severe stent pain and unplanned hospital visits. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Radioactive metallic stent for palliative treatment of esopageal cancer using Ho-166: an experimental study in canine model

    Energy Technology Data Exchange (ETDEWEB)

    Won, J. H.; Lee, J. D. [College of Medicine, Yonsei Univ., Seoul (Korea, Republic of); Wang, H. J.; Lim, H. E.; Park, C. H. [College of Medicine, Ajou Univ., Inchon (Korea, Republic of); Park, K. B. [KAERI, Taejon (Korea, Republic of)

    1999-07-01

    Self-expandable metallic stents are widely used for palliative treatment of esophageal cancer, however, tumor overgrowth and short survaval limit its long-term effect. The purpose of this study is to evaluate tissue response of the radiation effect in normal canine esophagus whether metallic stents coated with radioactive H-166 is effective for patients survival and preservation of stent patency longer than stents without radioactive materials. Ho-166 was incorporated within polyurethan (50{mu}) and coated over the outer surface of self-expandable metallic stents. Metallic stents with radioactivity of 4.0-7.8mCi (Group A), 1.0-1.8 mCi (Group B) and 0.5-0.7mCi (Group C) were placed in normal mid-esophagus in twelve dogs (Group A), five (Group B) and another five dogs (Group C) respectively, and the stents were tightly anchored by surgery to prevent migration. Estimated radiation dose was 6-70 Gy in Group C. Fluoroscopy confirmed stents in esophagus without migration for at least two days. The dogs were sacrified at two or three months later and histopathologic examinations were performed. In group A, mid-esophagus stricture, mucosal ulceration were found in all specimens. Severe fibrosis and degeneration of muscular propria, upper one half were found in three and complete fibrosis of esophageal wall, however, esophageal perforation was found but muscular layer was intact. In group C, no histological changes was demonstrated in three but submucosal inflammation with intact mucosa in two. In therapeutic dose level (group B), radioactive metallic stent showed radiation effect within esophageal wall without complication which might give additional palliative effect in malignant espohageal stricture.

  7. High-definition computed tomography for coronary artery stents imaging: Initial evaluation of the optimal reconstruction algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Xiaoming, E-mail: mmayzy2008@126.com; Li, Tao, E-mail: litaofeivip@163.com; Li, Xin, E-mail: lx0803@sina.com.cn; Zhou, Weihua, E-mail: wangxue0606@gmail.com

    2015-05-15

    Highlights: • High-resolution scan mode is appropriate for imaging coronary stent. • HD-detail reconstruction algorithm is stent-dedicated kernel. • The intrastent lumen visibility also depends on stent diameter and material. - Abstract: Objective: The aim of this study was to evaluate the in vivo performance of four image reconstruction algorithms in a high-definition CT (HDCT) scanner with improved spatial resolution for the evaluation of coronary artery stents and intrastent lumina. Materials and methods: Thirty-nine consecutive patients with a total of 71 implanted coronary stents underwent coronary CT angiography (CCTA) on a HDCT (Discovery CT 750 HD; GE Healthcare) with the high-resolution scanning mode. Four different reconstruction algorithms (HD-stand, HD-detail; HD-stand-plus; HD-detail-plus) were applied to reconstruct the stented coronary arteries. Image quality for stent characterization was assessed. Image noise and intrastent luminal diameter were measured. The relationship between the measurement of inner stent diameter (ISD) and the true stent diameter (TSD) and stent type were analysed. Results: The stent-dedicated kernel (HD-detail) offered the highest percentage (53.5%) of good image quality for stent characterization and the highest ratio (68.0 ± 8.4%) of visible stent lumen/true stent lumen for luminal diameter measurement at the expense of an increased overall image noise. The Pearson correlation coefficient between the ISD and TSD measurement and spearman correlation coefficient between the ISD measurement and stent type were 0.83 and 0.48, respectively. Conclusions: Compared with standard reconstruction algorithms, high-definition CT imaging technique with dedicated high-resolution reconstruction algorithm provides more accurate stent characterization and intrastent luminal diameter measurement.

  8. Efficacy of a dexamethasone-eluting nitinol stent on the inhibition of pseudointimal hyperplasia in a transjugular intrahepatic portosystemic shunt: an experimental study in a swine model

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Tae Seok [Korea University Guro Hospital, Seoul (Korea, Republic of); Oh, Joo Hyeogn; Park, Young Koo [Kyung Hee University Hospital, Seoul (Korea, Republic of); Song, Ho Young [University of Ulsan, College of Medicine, Seoul (Korea, Republic of); Park, Sang Joon [Hallym University, College of Medicine, Seoul (Korea, Republic of); Yuk, Sun Hong [Hannam University, Daejeon (Korea, Republic of)

    2005-12-15

    We wanted to evaluate the feasibility and efficacy of using a dexamethasone (DM)-eluting nitinol stent to inhibit the pseudointimal hyperplasia following stent placement in the transjugular intrahepatic portosystemic shunt tract (TIPS) of a swine. Fifteen stents were constructed using 0.15 mm-thick nitinol wire; they were 60 mm in length and 10 mm in diameter. The metallic stents were then classified into three types; type 1 and 2 was coated with the mixture of 12% and 20%, respectively, of DM solution and polyurethane (PU), while type 3 was a bare stent that was used for control study. In fifteen swine, each type of stent was implanted in the TIPS tract of 5 swine, and each animal was sacrificed 2 weeks after TIPS creation. The proliferation of the pseudointima was evaluated both on follow-up portogram and pathologic examination. One TIPS case, using the type 1 stent, and two TIPS cases, using the type 2 stent, maintained their luminal patency while the others were all occluded. On the histopathologic analysis, the mean of the maximum pseudointimal hyperplasia was expressed as the percentage of the stent radius that was patent, and these values were 51.2%, 50% and 76% for the type 1, 2, and 3 stents, respectively. The DM-eluting stent showed a tendency to reduce the development of pseudointimal hyperplasia in the TIPS tract of a swine model with induced-portal hypertension.

  9. A randomized study to compare bioactive titanium stents and everolimus-eluting stents in diabetic patients (TITANIC XV): 1-year results.

    Science.gov (United States)

    López-Mínguez, José R; Nogales-Asensio, Juan M; Doncel-Vecino, Luis J; Merchán-Herrera, Antonio; Pomar-Domingo, Francisco; Martínez-Romero, Pedro; Fernández-Díaz, José A; Valdesuso-Aguilar, Raúl; Moreu-Burgos, José; Díaz-Fernández, José

    2014-07-01

    Up to 25% of patients who undergo a percutaneous coronary intervention show some limitation in the use of drug-eluting stents. The aim of this study was to evaluate if titanium-nitride-oxide-coated stents could be a good alternative to everolimus-eluting stents in diabetic patients. A total of 173 diabetic patients with lesions at moderate risk of restenosis (exclusion criteria: diameter 28 mm in vessels < 3mm, chronic occlusion) were randomized to a titanium group (83 patients) or an everolimus group (90 patients). Baseline characteristics were well balanced; 28.3% of patients were insulin dependent. At 1 year, the incidence of major adverse cardiac events (death, nonfatal myocardial infarction, stroke, or repeat target vessel revascularization) was significantly higher in the titanium group than in the everolimus group (total, 14.5% vs 4.4%; P = .02; noninsulin-dependent subgroup, 9.7% vs 3.2%; P = .14; insulin-dependent subgroup, 28.6% vs 7.1%; P = .04). The incidence of death, nonfatal myocardial infarction, stroke, or any revascularization was 16.9% in the titanium group and 7.8% in the everolimus group (P = .06). Target lesion and vessel revascularizations occurred in 8.4% compared with 3.3% (P = .15) and in 13.3% compared with 3.3% (P = .01) in the titanium and everolimus groups, respectively. Angiographic follow-up at 9 months showed significantly less late lumen loss in the everolimus group (in-segment, 0.52 [standard deviation, 0.58) mm vs -0.05 [0.32] mm; in-stent, 0.76 [0.54] mm vs 0.13 [0.31] mm; P < .0001). The everolimus-eluting stent is superior to the titanium stent for clinical and angiographic end points in diabetic patients with lesions at moderate risk of restenosis. Copyright © 2013 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

  10. Preservation of keratinized mucosa around implants using a prefabricated implant-retained stent: a case-control study

    OpenAIRE

    Kim, Chang-Soon; Duong, Hieu Pham; Park, Jung-Chul; Shin, Hyun-Seung

    2016-01-01

    Purpose The aim of this study was to clinically assess the impact of a prefabricated implant-retained stent clipped over healing abutments on the preservation of keratinized mucosa around implants after implant surgery, and to compare it with horizontal external mattress sutures. Methods A total of 50 patients were enrolled in this study. In the test group, a prefabricated implant-retained stent was clipped on the healing abutment after implant surgery to replace the keratinized tissue bucco-...

  11. Changes in the mechanical environment of stenotic arteries during interaction with stents: computational assessment of parametric stent designs.

    Science.gov (United States)

    Holzapfel, Gerhard A; Stadler, Michael; Gasser, Thomas C

    2005-02-01

    Clinical studies have identified factors such as the stent design and the deployment technique that are one cause for the success or failure of angioplasty treatments. In addition, the success rate may also depend on the stenosis type. Hence, for a particular stenotic artery, the optimal intervention can only be identified by studying the influence of factors such as stent type, strut thickness, geometry of the stent cell, and stent-artery radial mismatch with the wall. We propose a methodology that allows a set of stent parameters to be varied, with the aim of evaluating the difference in the mechanical environment within the wall before and after angioplasty with stenting. Novel scalar quantities attempt to characterize the wall changes inform of the contact pressure caused by the stent struts, and the stresses within the individual components of the wall caused by the stent. These quantities are derived numerically and serve as indicators, which allow the determination of the correct size and type of the stent for each individual stenosis. In addition, the luminal change due to angioplasty may be computed as well. The methodology is demonstrated by using a full three-dimensional geometrical model of a postmortem specimen of a human iliac artery with a stenosis using imaging data. To describe the material behavior of the artery, we considered mechanical data of eight different vascular tissues, which formed the stenosis. The constitutive models for the tissue components capture the typical anisotropic, nonlinear and dissipative characteristics under supra-physiological loading conditions. Three-dimensional stent models were parametrized in such a way as to enable new designs to be generated simply with regard to variations in their geometric structure. For the three-dimensional stent-artery interaction we use a contact algorithm based on smooth contact surfaces of at least C-continuity, which prevents numerical problems known from standard facet-based contact

  12. The study of metal stents for effect to the radiation therapy

    International Nuclear Information System (INIS)

    Gao Li; Feng Ningyuan; Zhai Renyou; Yang Weizhi; Xu Guozhen; Wang Yafei

    2001-01-01

    Objective: To confirm whether the metal stents affect the radiation beam. Methods: The transmission factors from the national self-expanding esophagus stent, stainless self-expanding bile duct stent, and balloon-expanded vascular stent was supervised under 192 Ir irradiation in the air. Results: The transmission factors from the 3 kinds of metal stents were 0.993, 0.988, and 0.997, which meant that the attenuation of the stents to the radiation was 0.7%, 1.2%, and 0.3%, respectively (mean: 0.7%). Conclusion: The effect of the metal stents to the radiation was less than 1.2% and that meant there was no clinical significant effect on the patients irradiated following stent implantation or to perform the intra-stents brachytherapy

  13. The OCT-ORION Study: A Randomized Optical Coherence Tomography Study Comparing Resolute Integrity to Biomatrix Drug-Eluting Stent on the Degree of Early Stent Healing and Late Lumen Loss.

    Science.gov (United States)

    Lee, Stephen W L; Tam, Frankie C C; Lam, Simon C C; Kong, Shun-Ling; Shea, Catherine P; Chan, Kelvin K W; Wong, Michael K L; Chan, Michael P H; Wong, Anthony Y T; Yung, Arthur S Y; Lam, Yui-Ming; Zhang, Lei-Wei; Wu, Karl K Y; Mintz, Gary S; Maehara, Akiko

    2018-04-01

    Durable polymers used in drug-eluting stents are considered a potential cause of hypersensitivity inflammatory response adversely affecting stent healing. Using a sequential follow-up with optical coherence tomography, we compared the differences in healing profiles of 2 drug-eluting stents with a biodegradable or durable polymer. Sixty patients with multivessel disease were prospectively enrolled to receive both study stents, which were randomly assigned to 2 individual vessels, a Resolute Integrity zotarolimus-eluting stent with a durable BioLinx polymer and a BioMatrix NeoFlex Biolimus A9-eluting stent with a biodegradable polylactic acid polymer. Optical coherence tomography was performed at baseline, then in 5 randomly assigned monthly groups at 2 to 6 months, and at 9 months in all patients. The primary end point was the difference in optical coherence tomography strut coverage at 9 months. Key secondary end points included angiographic late lumen loss and composite major adverse cardiac events (cardiac death, myocardial infarction, target lesion revascularization, and definite or probable stent thrombosis) at 9 months. Resolute Integrity zotarolimus-eluting stent showed significantly better strut coverage than BioMatrix NeoFlex Biolimus A9-eluting stent at 2 to 6 months ( P <0.001) and less variance of percent coverage at 9 months, 99.7% (interquartile range, 99.1-100) versus 99.6% (interquartile range, 96.8-99.9; difference, 0.10; 95% confidence interval, 0.00-1.05; P <0.001). No significant difference was observed in major adverse cardiac events or angiographic end points. Despite having a durable polymer, Resolute Integrity zotarolimus-eluting stent exhibited better strut coverage than BioMatrix NeoFlex Biolimus A9-eluting stent having a biodegradable polymer; both showed similar antiproliferative efficacy. This novel, longitudinal, sequential optical coherence tomography protocol using each patient as own control could achieve conclusive results in small

  14. Concepts to optimize stent-grafting of abdominal aortic aneurysms based on results of experimental studies

    International Nuclear Information System (INIS)

    Chavan, A.; Kirchhoff, T.; Baus, S.; Galanski, M.; Pichlmaier, M.

    2001-01-01

    Purpose. In the endoluminal therapy of abdominal aortic aneurysms, a short proximal aneurysm neck, endoleaks and the large size and stiffness of the introducer systems are responsible for many of the complications and sub-optimal outcomes. The purpose of the present review article is to to suggest strategies to minimize these complications based on the results of experimental studies in animals. Material and methods. After implanting various types of stents across the renal artery origins, the functional and morphological changes in the kidneys and renal vessels were studied by various authors. In order to prevent progressive widening of the proximal aneurysmal neck and graft dislocation, Sonesson et al. performed a laparoscopic banding around the proximal neck in pigs. To study the effects of endoleaks, Marty, Schurink and Pitton carried out pressure measurements in experimental aneurysms with and without endoleaks. Sakaguchi and Pavcnik developed the 'Twin-tube endografts' (TTEG) and the 'Bifurcated drum occluder endografts' (BDOEG) and tested them in dogs. Results. Up to 3 months after suprarenal stent placement, Chavan et al. detected no significant fall in the mean inulin clearance in sheep (140±46 ml/min before, 137±58 ml/min after). Nasim et al. and Malina et al. reported similar observations with respect to renal function. Suprarenal fixation may result in isolated thrombotic occlusions of the renal arteries and microinfarcts in the kidneys. Mean aortic diameters at the level of banding were significantly smaller in the animals with aortic banding as opposed to those in the control group without banding (8 mm vs 11 mm, p=0.004). The banding caused a secure proximal fixation of the stent-graft. Persistent endoleaks resulted in significantly higher intraaneurysmal pressures. Although the TTEG and the BDOEG stent-grafts required smaller sheaths, occlusions were observed in 8% (TTEG) and 60% (BDOEG) of the graft limbs. (orig.) [de

  15. Experimental study of the preventive effect of 1'03Pd stent on in-stent restenosis in rabbit iliac artery

    International Nuclear Information System (INIS)

    Luo Quanyong; Chen Libo; Yuan Zhibin; Lu Hankui; Zhu Ruisen

    2003-01-01

    Objective: To investigate the ability of γ-emitting 103 Pd radioactive stent implantation for preventing in-stent restenosis in iliac artery of rabbits. Methods: Twenty New Zealand white rabbits were divided into six groups on the basis of radioactivity loading [2.22 (n=3), 5.55 (n=4), 9.25 (n=4), 14.8 (n=3), 22.2 (n=3), 33.3 MBq (n=3)]. 103 Pd stent was implanted in one of the two iliac arteries of each rabbit and nonradioactive stent in the contralateral artery. The rabbits were fed with high fat diet. Treatment efficiency was assessed by angiography and quantitative histomorphometry of the stented iliac segments 28 d after the implantation. Results: Quantitative histomorphometry analysis indicated that 103 Pd stents induced a significant reduction in neointimal area and the percentage of stenosis within radioactive stents was lower compared with that in the control stents. Nevertheless, the suppression of neointima formation by 103 Pd stent implantation was not in a dose-dependent manner. Conclusions: Low-dose intravascular brachytherapy via a γ-particle-emitting 103 Pd radioactive stent potently inhibits neointimal hyperplasia and prevents the in-stent restenosis in rabbit iliac artery. 103 Pd stent implantation probably can be employed as a novel means to prevent in-stent restenosis

  16. Bioabsorbable polymer-coated sirolimus-eluting stent implantation preserves coronary vasomotion: A DESSOLVE II trial sub-study.

    Science.gov (United States)

    Rusinaru, Dan; Vrolix, Mathias; Verheye, Stefan; Chowdhary, Saqib; Schoors, Danny; Di Mario, Carlo; Desmet, Walter; Donohoe, Dennis J; Ormiston, John A; Knape, Charlene; Bezerra, Hiram; Lansky, Alexandra; Wijns, William

    2015-12-01

    We studied coronary vasomotion in patients treated with the Mistent(®) absorbable polymer sirolimus-eluting stent (APSES) and in patients implanted with the Endeavor(®) zotarolimus-eluting stent (ZES). First generation (1st-gen) drug-eluting stents (DES) induce persistent vasomotor dysfunction in the treated coronary artery. It is unknown whether and to what extent the implantation of an absorbable polymer DES impairs coronary vasomotion. This sub-study of the DESSOLVE II trial included 19 APSES Mistent(®) and 10 ZES Endeavor(®) patients. Incremental atrial pacing and quantitative coronary angiography were used to assess vasomotion proximal and distal to the stent and in a reference segment at 9 months after implantation. Percent changes in vessel diameter with pacing versus baseline were calculated and compared. Vasomotor response of the APSES group was also compared with changes observed in a historical group of 17 patients implanted with a 1st-gen sirolimus-eluting stent (SES). Normal vasomotion (vasodilatation) was preserved and of comparable magnitude in the APSES and in the ZES group both proximally (P = 0.34) and distally (P = 0.38) to the stent. This finding was not observed in the 1st-gen SES group showing marked pacing-induced vasoconstriction at both stent edges (P absorbable polymer sirolimus-eluting stent is associated with preserved coronary vasomotion, comparable to that observed after implantation of the Endeavor(®) ZES, and distinct from 1st-gen SES which induce coronary vasomotor dysfunction. © 2015 Wiley Periodicals, Inc.

  17. Self-expandable metal stents for malignant colonic obstruction: data from a retrospective regional SIED-AIGO study.

    Science.gov (United States)

    Di Mitri, Roberto; Mocciaro, Filippo; Traina, Mario; Montalbano, Luigi Maria; Familiari, Luigi; D'Amore, Fabio; Raimondo, Dario; Virgilio, Clara; Tarantino, Ilaria; Barresi, Luca; Giunta, Marco; Borina, Eleonora; Borruto, Antonino; Marino, Antonino

    2014-03-01

    Self-expandable metal stents are a non-surgical option for the treatment of symptomatic malignant colorectal obstruction as palliative treatment or as a bridge to surgery. To report data from a regional study on self-expandable metal stent (SEMS) placement for malignant colorectal obstruction. Two hundred and four patients (male 54.9%, mean age of 69.5 ± 14.2) were retrospectively evaluated and data on technical and clinical success, and complications, were analyzed. Technical and clinical success rates were 99% and 94.6% respectively, with 36.7% treated on an emergency basis and 63.3% electively. Palliative treatment was administered to 70.1%, and as a bridge to surgery for 29.9%. Complications were 17 neoplastic ingrowths, 10 stent migrations, and 4 perforations. Palliative treatment was associated with a higher risk of stent ingrowth (p=0.003), and chemotherapy with a lower risk of stent ingrowth (p=0.009). This regional study, although it has certain limitations, confirms the positive role of self-expandable metal stents in the treatment of symptomatic malignant colorectal obstruction, and that chemotherapy decreases the risk of ingrowth. Copyright © 2013 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

  18. Immediate, short-, and long-term changes in tracheal stent diameter, length, and positioning after placement in dogs with tracheal collapse syndrome.

    Science.gov (United States)

    Raske, Matthew; Weisse, Chick; Berent, Allyson C; McDougall, Renee; Lamb, Kenneth

    2018-03-01

    Intraluminal tracheal stenting is a minimally invasive procedure shown to have variable degrees of success in managing clinical signs associated with tracheal collapse syndrome (CTCS) in dogs. Identify immediate post-stent changes in tracheal diameter, determine the extent of stent migration, and stent shortening after stent placement in the immediate-, short-, and long-term periods, and evaluate inter-observer reliability of radiographic measurements. Fifty client-owned dogs. Retrospective study in which medical records were reviewed in dogs with CTCS treated with an intraluminal tracheal stent. Data collected included signalment, location, and type of collapse, stent diameter and length, and post-stent placement radiographic follow-up times. Radiographs were used to obtain pre-stent tracheal measurements and post-stent placement measurements. Immediate mean percentage change was 5.14%, 5.49%, and 21.64% for cervical, thoracic inlet, and intra-thoracic tracheal diameters, respectively. Ultimate mean follow-up time was 446 days, with mean percentage change of 2.55%, 15.09%, and 8.65% for cervical, thoracic inlet, and intra-thoracic tracheal diameters, respectively. Initial mean stent length was 26.72% higher than nominal length and ultimate long-term tracheal mean stent shortening was only 9.90%. No significant stent migration was identified in the immediate, short-, or long-term periods. Good inter-observer agreement of radiographic measurements was found among observers of variable experience level. Use of an intraluminal tracheal stent for CTCS is associated with minimal stent shortening with no clinically relevant stent migration after fluoroscopic placement. Precise stent sizing and placement techniques likely play important roles in avoiding these reported complications. Copyright © 2018 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

  19. Immediate, short‐, and long‐term changes in tracheal stent diameter, length, and positioning after placement in dogs with tracheal collapse syndrome

    Science.gov (United States)

    Raske, Matthew; Berent, Allyson C.; McDougall, Renee; Lamb, Kenneth

    2018-01-01

    Background Intraluminal tracheal stenting is a minimally invasive procedure shown to have variable degrees of success in managing clinical signs associated with tracheal collapse syndrome (CTCS) in dogs. Objectives Identify immediate post‐stent changes in tracheal diameter, determine the extent of stent migration, and stent shortening after stent placement in the immediate‐, short‐, and long‐term periods, and evaluate inter‐observer reliability of radiographic measurements. Animals Fifty client‐owned dogs. Methods Retrospective study in which medical records were reviewed in dogs with CTCS treated with an intraluminal tracheal stent. Data collected included signalment, location, and type of collapse, stent diameter and length, and post‐stent placement radiographic follow‐up times. Radiographs were used to obtain pre‐stent tracheal measurements and post‐stent placement measurements. Results Immediate mean percentage change was 5.14%, 5.49%, and 21.64% for cervical, thoracic inlet, and intra‐thoracic tracheal diameters, respectively. Ultimate mean follow‐up time was 446 days, with mean percentage change of 2.55%, 15.09%, and 8.65% for cervical, thoracic inlet, and intra‐thoracic tracheal diameters, respectively. Initial mean stent length was 26.72% higher than nominal length and ultimate long‐term tracheal mean stent shortening was only 9.90%. No significant stent migration was identified in the immediate, short‐, or long‐term periods. Good inter‐observer agreement of radiographic measurements was found among observers of variable experience level. Conclusions and Clinical Importance Use of an intraluminal tracheal stent for CTCS is associated with minimal stent shortening with no clinically relevant stent migration after fluoroscopic placement. Precise stent sizing and placement techniques likely play important roles in avoiding these reported complications. PMID:29460368

  20. Angiographic analysis of animal model aneurysms treated with novel polyurethane asymmetric vascular stent (P-AVS): feasibility study.

    Science.gov (United States)

    Ionita, Ciprian N; Dohatcu, Andreea; Sinelnikov, Andrey; Sherman, Jason; Keleshis, Christos; Paciorek, Ann M; Hoffmann, K R; Bednarek, D R; Rudin, S

    2009-01-01

    Image-guided endovascular intervention (EIGI), using new flow modifying endovascular devices for intracranial aneurysm treatment is an active area of stroke research. The new polyurethane-asymmetric vascular stent (P-AVS), a vascular stent partially covered with a polyurethane-based patch, is used to cover the aneurysm neck, thus occluding flow into the aneurysm. This study involves angiographic imaging of partially covered aneurysm orifices. This particular situation could occur when the vascular geometry does not allow full aneurysm coverage. Four standard in-vivo rabbit-model aneurysms were investigated; two had stent patches placed over the distal region of the aneurysm orifice while the other two had stent patches placed over the proximal region of the aneurysm orifice. Angiographic analysis was used to evaluate aneurysm blood flow before and immediately after stenting and at four-week follow-up. The treatment results were also evaluated using histology on the aneurysm dome and electron microscopy on the aneurysm neck. Post-stenting angiographic flow analysis revealed aneurysmal flow reduction in all cases with faster flow in the distally-covered case and very slow flow and prolonged pooling for proximal-coverage. At follow-up, proximally-covered aneurysms showed full dome occlusion. The electron microscopy showed a remnant neck in both distally-placed stent cases but complete coverage in the proximally-placed stent cases. Thus, direct flow (impingement jet) removal from the aneurysm dome, as indicated by angiograms in the proximally-covered case, was sufficient to cause full aneurysm healing in four weeks; however, aneurysm healing was not complete for the distally-covered case. These results support further investigations into the treatment of aneurysms by flow-modification using partial aneurysm-orifice coverage.

  1. Carotid artery stenting compared with endarterectomy in patients with symptomatic carotid stenosis (International Carotid Stenting Study): an interim analysis of a randomised controlled trial.

    LENUS (Irish Health Repository)

    Ederle, Jörg

    2010-03-20

    Stents are an alternative treatment to carotid endarterectomy for symptomatic carotid stenosis, but previous trials have not established equivalent safety and efficacy. We compared the safety of carotid artery stenting with that of carotid endarterectomy.

  2. Carotid artery stenting compared with endarterectomy in patients with symptomatic carotid stenosis (International Carotid Stenting Study): an interim analysis of a randomised controlled trial.

    NARCIS (Netherlands)

    Ederle, J.; Dobson, J.; Featherstone, R.L.; Bonati, L.H.; Worp, H.B. van der; Borst, G.J. de; Lo, T.H.; Gaines, P.; Dorman, P.J.; Macdonald, S.; Lyrer, P.A.; Hendriks, J.M.; McCollum, C.; Nederkoorn, P.J.; Brown, M.M.; Blankensteijn, J.D.; Leeuw, F.E. de; Schultze Kool, L.J.; Vliet, J.A. van der; et al.,

    2010-01-01

    BACKGROUND: Stents are an alternative treatment to carotid endarterectomy for symptomatic carotid stenosis, but previous trials have not established equivalent safety and efficacy. We compared the safety of carotid artery stenting with that of carotid endarterectomy. METHODS: The International

  3. Carotid artery stenting compared with endarterectomy in patients with symptomatic carotid stenosis (International Carotid Stenting Study): an interim analysis of a randomised controlled trial

    NARCIS (Netherlands)

    Ederle, Jörg; Dobson, Joanna; Featherstone, Roland L.; Bonati, Leo H.; van der Worp, H. Bart; de Borst, Gert J.; Lo, T. Hauw; Gaines, Peter; Dorman, Paul J.; Macdonald, Sumaira; Lyrer, Philippe A.; Hendriks, Johanna M.; McCollum, Charles; Nederkoorn, Paul J.; Brown, Martin M.; Algra, A.; Bamford, J.; Beard, J.; Bland, M.; Bradbury, A. W.; Brown, M. M.; Clifton, A.; Gaines, P.; Collins, R.; Molyneux, A.; Naylor, R.; Warlow, C.; Ferro, J. M.; Thomas, D.; Bonati, L. H.; Coward, L.; Dobson, J.; Ederle, J.; Featherstone, R. F.; Tindall, H.; McCabe, D. J. H.; Wallis, A.; Brooks, M.; Chambers, B.; Chan, A.; Chu, P.; Clark, D.; Dewey, H.; Donnan, G.; Fell, G.; Hoare, M.; Molan, M.; Roberts, A.; Roberts, N.; Beiles, B.; Bladin, C.; Clifford, C.; Grigg, M.; New, G.; Bell, R.; Bower, S.; Chong, W.; Holt, M.; Saunder, A.; Than, P. G.; Gett, S.; Leggett, D.; McGahan, T.; Quinn, J.; Ray, M.; Wong, A.; Woodruff, P.; Foreman, R.; Schultz, D.; Scroop, R.; Stanley, B.; Allard, B.; Atkinson, N.; Cambell, W.; Davies, S.; Field, P.; Milne, P.; Mitchell, P.; Tress, B.; Yan, B.; Beasley, A.; Dunbabin, D.; Stary, D.; Walker, S.; Cras, P.; d'Archambeau, O.; Hendriks, J. M. H.; van Schil, P.; St Blasius, A. Z.; Bosiers, M.; Deloose, K.; van Buggenhout, E.; de Letter, J.; Devos, V.; Ghekiere, J.; Vanhooren, G.; Astarci, P.; Hammer, F.; Lacroix, V.; Peeters, A.; Verbist, J.; Blair, J.-F.; Caron, J. L.; Daneault, N.; Giroux, M.-F.; Guilbert, F.; Lanthier, S.; Lebrun, L.-H.; Oliva, V.; Raymond, J.; Roy, D.; Soulez, G.; Weill, A.; Hill, M.; Hu, W.; Hudion, M.; Morrish, W.; Sutherland, G.; Wong, J.; Albäck, A.; Harno, H.; Ijäs, P.; Kaste, M.; Lepäntalo, M.; Mustanoja, S.; Paananen, T.; Porras, M.; Putaala, J.; Railo, M.; Sairanen, T.; Soinne, L.; Vehmas, A.; Vikatmaa, P.; Goertler, M.; Halloul, Z.; Skalej, M.; Brennan, P.; Kelly, C.; Leahy, A.; Moroney, J.; Thornton, J.; Koelemay, M. J. W.; Reekers, J. A. A.; Roos, Y. B. W. E. M.; Hendriks, J. M.; Koudstaal, P. J.; Pattynama, P. M. T.; van der Lugt, A.; van Dijk, L. C.; van Sambeek, M. R. H. M.; van Urk, H.; Verhagen, H. J. M.; Bruijninckx, C. M. A.; de Bruijn, S. F.; Keunen, R.; Knippenberg, B.; Mosch, A.; Treurniet, F.; van Dijk, L.; van Overhagen, H.; Wever, J.; de Beer, F. C.; van den Berg, J. S. P.; van Hasselt, B. A. A. M.; Zeilstra, D. J.; Boiten, J.; van Otterloo, J. C. A. de Mol; de Vries, A. C.; Lycklama a Nijeholt, G. J.; van der Kallen, B. F. W.; Blankensteijn, J. D.; de Leeuw, F. E.; Kool, L. J. Schultze; van der Vliet, J. A.; de Borst, G. J.; de Kort, G. A. P.; Kapelle, L. J.; Lo, T. H.; Mali, W. P. Th M.; Moll, F.; van der Worp, H. B.; Verhagen, H.; Barber, P. A.; Bourchier, R.; Hill, A.; Holden, A.; Stewart, J.; Bakke, S. J.; Krohg-Sørensen, K.; Skjelland, M.; Tennøe, B.; Bialek, P.; Biejat, Z.; Czepiel, W.; Czlonkowska, A.; Dowzenko, A.; Jedrzejewska, J.; Kobayashi, A.; Lelek, M.; Polanski, J.; Kirbis, J.; Milosevic, Z.; Zvan, B.; Blasco, J.; Chamorro, A.; Macho, J.; Obach, V.; Riambau, V.; San Roman, L.; Branera, J.; Canovas, D.; Estela, Jordi; Gaibar, A. Gimenez; Perendreu, J.; Björses, K.; Gottsater, A.; Ivancev, K.; Maetzsch, T.; Sonesson, B.; Berg, B.; Delle, M.; Formgren, J.; Gillgren, P.; Kall, T.-B.; Konrad, P.; Nyman, N.; Takolander, R.; Andersson, T.; Malmstedt, J.; Soderman, M.; Wahlgren, C.; Wahlgren, N.; Binaghi, S.; Hirt, L.; Michel, P.; Ruchat, P.; Engelter, S. T.; Fluri, F.; Guerke, L.; Jacob, A. L.; Kirsch, E.; Lyrer, P. A.; Radue, E.-W.; Stierli, P.; Wasner, M.; Wetzel, S.; Bonvin, C.; Kalangos, A.; Lovblad, K.; Murith, M.; Ruefenacht, D.; Sztajzel, R.; Higgins, N.; Kirkpatrick, P. J.; Martin, P.; Varty, K.; Adam, D.; Bell, J.; Crowe, P.; Gannon, M.; Henderson, M. J.; Sandler, D.; Shinton, R. A.; Scriven, J. M.; Wilmink, T.; D'Souza, S.; Egun, A.; Guta, R.; Punekar, S.; Seriki, D. M.; Thomson, G.; Brennan, J. A.; Enevoldson, T. P.; Gilling-Smith, G.; Gould, D. A.; Harris, P. L.; McWilliams, R. G.; Nasser, H.-C.; White, R.; Prakash, K. G.; Serracino-Inglott, F.; Subramanian, G.; Symth, J. V.; Walker, M. G.; Clarke, M.; Davis, M.; Dixit, S. A.; Dorman, P.; Dyker, A.; Ford, G.; Golkar, A.; Jackson, R.; Jayakrishnan, V.; Lambert, D.; Lees, T.; Louw, S.; Macdonald, S.; Mendelow, A. D.; Rodgers, H.; Rose, J.; Stansby, G.; Wyatt, M.; Baker, T.; Baldwin, N.; Jones, L.; Mitchell, D.; Munro, E.; Thornton, M.; Baker, D.; Davis, N.; Hamilton, G.; McCabe, D.; Platts, A.; Tibballs, J.; Cleveland, T.; Dodd, D.; Lonsdale, R.; Nair, R.; Nassef, A.; Nawaz, S.; Venables, G.; Belli, A.; Cloud, G.; Halliday, A.; Markus, H.; McFarland, R.; Morgan, R.; Pereira, A.; Thompson, A.; Chataway, J.; Cheshire, N.; Gibbs, R.; Hammady, M.; Jenkins, M.; Malik, I.; Wolfe, J.; Adiseshiah, M.; Bishop, C.; Brew, S.; Brookes, J.; Jäger, R.; Kitchen, N.; Ashleigh, R.; Butterfield, S.; Gamble, G. E.; McCollum, C.; Nasim, A.; O'Neill, P.; Edwards, R. D.; Lees, K. R.; MacKay, A. J.; Moss, J.

    2010-01-01

    BACKGROUND: Stents are an alternative treatment to carotid endarterectomy for symptomatic carotid stenosis, but previous trials have not established equivalent safety and efficacy. We compared the safety of carotid artery stenting with that of carotid endarterectomy. METHODS: The International

  4. Carotid artery stenting compared with endarterectomy in patients with symptomatic carotid stenosis (International Carotid Stenting Study) : an interim analysis of a randomised controlled trial

    NARCIS (Netherlands)

    Ederle, Joerg; Dobson, Joanna; Featherstone, Roland L.; Bonati, Leo H.; van der Worp, H. Bart; de Borst, Gert J.; Lo, T. Hauw; Gaines, Peter; Dorman, Paul J.; Macdonald, Sumaira; Lyrer, Philippe A.; Hendriks, Johanna M.; McCollum, Charles; Nederkoorn, Paul J.; Brown, Martin M.; Algra, A.; Bamford, J.; Beard, J.; Bland, M.; Bradbury, A. W.; Brown, M. M.; Clifton, A.; Gaines, P.; Hacke, W.; Halliday, A.; Malik, I.; Mas, J. L.; McGuire, A. J.; Sidhu, P.; Venables, G.; Bradbury, A.; Brown, M. M.; Clifton, A.; Gaines, P.; Collins, R.; Molynewc, A.; Naylor, R.; Warlow, C.; Ferro, J. M.; Thomas, D.; Bonati, L. H.; Coward, L.; Dobson, J.; Ederle, J.; Featherstone, R. F.; Tindall, H.; McCabe, D. J. H.; Wallis, A.; Hendriks, J. M. H.; Hendriks, J. M.

    2010-01-01

    Background Stents are an alternative treatment to carotid endarterectomy for symptomatic carotid stenosis, but previous trials have not established equivalent safety and efficacy. We compared the safety of carotid artery stenting with that of carotid endarterectomy. Methods The International Carotid

  5. Expandable stents.

    Science.gov (United States)

    Nesbitt, J C; Carrasco, H

    1996-05-01

    Expandable metallic stents are effective in selected patients with malignant or benign airway stenoses. When used for malignant lesions, the primary purpose of the stent is to improve the quality of life; stents are usually chosen for palliation of symptoms in recognition of the low likelihood of success for other therapy. For patients with benign stenoses, the stents provide a permanent source of structural support to alleviate the narrowed segment. The advantages of the expandable metallic stents are as follows: (1) they can be inserted through an endotracheal tube or under local anesthesia with relative simplicity under fluoroscopic guidance; (2) they do not impair the drainage of sputum because ciliary movement is not interrupted; (3) over a period of a few weeks, the meshwork is gradually covered with mucosa as the stent becomes incorporated into the airway wall; (4) ventilation usually is not impaired if the metallic mesh stent covers another nonstenosed bronchus, because the interstices of the stent are nonobstructive; and (5) they are dynamic and continue to expand over time, particularly if concurrent treatment achieves an effect on the lesion that caused stenosis. Disadvantages of the expandable stent include (1) they often are only temporarily effective for tracheobronchial stenosis due to intraluminal tumor or granulation tissue, both of which can grow between the wires; (2) they are considered permanent stents because removal is difficult; and (3) they can be poorly positioned during placement or can become displaced by progressive migration after placement, and they cannot be repositioned. A relative contraindication to insertion is an inflammatory process or infection that can predispose to granulation formation, particularly at the points of maximal contact pressure of the stent to the airway mucosa. In the presence of inflammation, it may be better to use a silicone prosthesis until the inflammatory process subsides and fibrosis occurs. Granulation

  6. A method to determine the kink resistance of stents and stent delivery systems according to international standards

    Directory of Open Access Journals (Sweden)

    Brandt-Wunderlich Christoph

    2016-09-01

    Full Text Available The kink behavior of vascular stents is of particular interest for clinicians, stent manufacturers and regulatory as a kinked stent generates a lumen loss in the stented vessel and can lead to in-stent restenosis. In this study methods to determine the kink resistance of stents and stent delivery systems according to the ISO 25539-2 and FDA guidance no. 1545 were presented. The methods are applicable for balloon expandable stents as well as for self-expanding stents and determine the lumen loss and residual diameter change dependent on the specific bending radius.

  7. Progress in the study of drug-eluting intra-stent thrombosis

    International Nuclear Information System (INIS)

    Guo Zhifu; Zheng Xing; Qin Yongwen

    2007-01-01

    Durg-eluting stent has been regarded as the milestone in the history of PCI for their efficiency in the prevention of coronary arterial restenosis after percutaneous coronary intervention. But unfortunately intra-stent thrombosis continues to be a serious complication of contemporary DES use. The incidence of drug-eluting stents thrombosis is at least not lower than that of bare metal stents at present. The clinical consequences of stent thrombosis are frequently catastrophic, including death in 40% to 50% of the cases or major myocardial infarction in 60% to 70%. Premature discontinuation of standard antiplatelet therapy is by far the most important predictor of stent thrombosis with DES and other predictors included renal failure, diabetes, bifurcation lesions, multiple lesions or multivessel disease, long stents, female, advanced age, stent underexpansion and residual stenosis etc. The delayed endothelialization may be the underling mechanism of DES thrombosis. (authors)

  8. Endovenous radiofrequency ablation using stent-type electrode for varicose veins: an experimental study in goats

    Energy Technology Data Exchange (ETDEWEB)

    Won, Je Hwan; Han, Jae Ho; Oh, Chang Kwon [Ajou University Hospital, Suwon (Korea, Republic of); Kwak, Young Lan [Yonsei University College of Medicine, Seoul (Korea, Republic of); Park, Sung Il [Ulsan University GangNeung Asan Hospital, Gangeung (Korea, Republic of)

    2004-10-15

    The purpose of this study was to investigate the feasibility and the optimal conditions of radiofrequency (RF) ablation by using the stent-type electrode upon the saphenous vein of goats for the endovenous treatment of varicose veins. A self-expandable nitinol stent electrode (6 mm diameter, 2 cm length, cell size; 1.3 x 2 mm) was designed to expose the distal 1 cm segment to allow for contact with the venous wall. The proximal part of the electrode was connected to the RF generator by insulated copper wires located within the stent electrode introducer. Initially, to optimize the power setting, ablation of 6 saphenous veins in 3 goats was performed with power settings of 10, 20 and 30 W. Pull back rate of the electrode was 2 and 4 cm/min for each power level, respectively. The goats were sacrificed 4-6 weeks later and histologic examinations of the saphenous veins were done. For the second part of the experiment, RF ablation of 4 saphenous veins from 2 goats was done by applying the optimal power, based upon the first examination; these procedure was performed with variable pull back rates. Again, the goats were sacrificed 1-6 weeks later and histologic examinations were done. Endovenous ablation of the goat saphenous veins at 20 W caused complete obliteration without complication. There was incomplete occlusion at 10 W, and there were vessel perforation, extravasation, and adjacent tissue injury at 30 W. In second part of the study, the complete circumferential obliteration of the vein was demonstrated at a pull back rate of 1 cm/min and 3 cm/min with the power of 20 W. The stent-type electrode may be useful in endovenous RF ablation for treatment of varicose veins. For stents with a diameter of 6 mm, the optional combination of 20 W of power with a pull back rate of 1-3 cm/min produced the most favorable results. Further study and clinical investigations are warranted.

  9. Endovenous radiofrequency ablation using stent-type electrode for varicose veins: an experimental study in goats

    International Nuclear Information System (INIS)

    Won, Je Hwan; Han, Jae Ho; Oh, Chang Kwon; Kwak, Young Lan; Park, Sung Il

    2004-01-01

    The purpose of this study was to investigate the feasibility and the optimal conditions of radiofrequency (RF) ablation by using the stent-type electrode upon the saphenous vein of goats for the endovenous treatment of varicose veins. A self-expandable nitinol stent electrode (6 mm diameter, 2 cm length, cell size; 1.3 x 2 mm) was designed to expose the distal 1 cm segment to allow for contact with the venous wall. The proximal part of the electrode was connected to the RF generator by insulated copper wires located within the stent electrode introducer. Initially, to optimize the power setting, ablation of 6 saphenous veins in 3 goats was performed with power settings of 10, 20 and 30 W. Pull back rate of the electrode was 2 and 4 cm/min for each power level, respectively. The goats were sacrificed 4-6 weeks later and histologic examinations of the saphenous veins were done. For the second part of the experiment, RF ablation of 4 saphenous veins from 2 goats was done by applying the optimal power, based upon the first examination; these procedure was performed with variable pull back rates. Again, the goats were sacrificed 1-6 weeks later and histologic examinations were done. Endovenous ablation of the goat saphenous veins at 20 W caused complete obliteration without complication. There was incomplete occlusion at 10 W, and there were vessel perforation, extravasation, and adjacent tissue injury at 30 W. In second part of the study, the complete circumferential obliteration of the vein was demonstrated at a pull back rate of 1 cm/min and 3 cm/min with the power of 20 W. The stent-type electrode may be useful in endovenous RF ablation for treatment of varicose veins. For stents with a diameter of 6 mm, the optional combination of 20 W of power with a pull back rate of 1-3 cm/min produced the most favorable results. Further study and clinical investigations are warranted

  10. Bilateral metal stents for hilar biliary obstruction using a 6Fr delivery system: outcomes following bilateral and side-by-side stent deployment.

    Science.gov (United States)

    Law, Ryan; Baron, Todd H

    2013-09-01

    Controversy exists on optimal endoscopic management for palliation of malignant hilar obstruction, with advocates for metal "side-by-side" (SBS) and "stent-in-stent" (SIS) techniques. We sought to evaluate the technical feasibility, efficacy, and outcomes of bilateral biliary self-expanding metal stents (SEMS) for treatment of malignant hilar obstruction using a stent with a 6Fr delivery system. This was a single-center, retrospective review of all patients who underwent bilateral placement of Zilver® biliary SEMS for malignant hilar obstruction from January 2010 to August 2012. Patients underwent endoscopic retrograde cholangiopancreatography with placement of stents using either the SIS or SBS stent techniques. Twenty-four patients (19 men, mean age 63 years) underwent bilateral stenting for malignant hilar obstruction during the study period. Seventeen and seven patients underwent the SBS and SIS technique, respectively. Cholangiocarcinoma (n=14) was the most common cause of hilar obstruction. Initial technical success was achieved in 24/24 (100%) of patients; however, 12 (50%) patients required re-intervention during the study period (median 98 days). Comparison of the SBS and SIS groups revealed no statistical difference with respect to need for re-intervention (P=0.31), successful re-intervention (P=0.60), or procedural length (P=0.89). Use of bilateral Zilver® SEMS in either the SBS or SIS configuration is safe, technically feasible, and effective for drainage of malignant hilar obstruction; however, duration of stent patency and procedure-free survival remain variable.

  11. Fluoroscopic guidance of retrograde exchange of ureteral stents in women.

    Science.gov (United States)

    Chang, Ruey-Sheng; Liang, Huei-Lung; Huang, Jer-Shyung; Wang, Po-Chin; Chen, Matt Chiung-Yu; Lai, Ping-Hong; Pan, Huay-Ben

    2008-06-01

    The purpose of this study was to review our experience with fluoroscopically guided retrograde exchange of ureteral stents in women. During a 48-month period, 28 women (age range, 38-76 years) were referred to our department for retrograde exchange of a ureteral stent. The causes of urinary obstruction were tumor compression in 26 patients and benign fibrotic stricture in two patients. A large-diameter snare catheter (25-mm single loop or 18- to 35-mm triple loop) or a foreign body retrieval forceps (opening width, 11.3 mm) was used to grasp the bladder end of the stent under fluoroscopic guidance. The technique entailed replacement of a patent or occluded ureteral stent with a 0.035- or 0.018-inch guidewire with or without the aid of advancement of an angiographic sheath. A total of 54 ureteral stents were exchanged with a snare catheter in 42 cases or a forceps in 12 cases. One stent misplaced too far up the ureter was replaced successfully through antegrade percutaneous nephrostomy. Ten occluded stents, including one single-J stent, were managed with a 0.018-inch guidewire in three cases, advancement of an angiographic sheath over the occluded stent into the ureter in five cases, and recannulation of the ureteral orifice with a guidewire in two cases. No complications of massive hemorrhage, ureter perforation, or infection were encountered. With proper selection of a snare or forceps catheter, retrograde exchange of ureteral stents in women can be easily performed under fluoroscopic guidance with high technical success and a low complication rate.

  12. The structural study of prefabrication stress stent and the hemodynamics in percutaneous transhepatic portacaval shunt

    International Nuclear Information System (INIS)

    Chu Jianguo; Sun Xiaoli; Zhou Yijun; Huang He; Zhou Hua; Lv Chunyan; Yang Shuhui

    2006-01-01

    Objective: To present a preliminary latest procedure for portal hypertension and evaluate the technical feasibility and efficacy of portacaval shunt creation through the percutaneous transhepatic approach in order to make a hemodynamic comparison with that of the classic TIPS. Methods: Thirty-eight patients with portal hypertension (36 men; mean age 57 years, range 32-73) were referred for PTPS procedure because of bleeding varices (n=36), intractable ascites (n=1), and hepatopulmonary syndrome (n=1). The severity of liver disease was classified as Child-Pugh B in 27 and C in 11. The PTPS was created by a percutaneous transhepatic puncture into right portal vein and then through left portal vein to the hepatic segment of IVC followed by a prefabrication stress stent-graft placement at the very site. Results: Technical and functional success of 100% was achieved in all patients, without related complications. The postprocedural portal vein-IVC gradients mean 13 cmH 2 O was achieved with the follow-up period mean 493 days. No recurrence of variceal bleeding and controlled refractory ascites were achieved, and still more with primary patency rate of the involved vascular structure up to 94.8% at 365 days, much better than classic TIPS. Conclusions: Portacaval shunt creation using the prefabrication stress stent via percutaneous transhepatic technique is safe and feasible. the compact coincidence was obtained between the stent and the involved vessel with restoration of intrahepatic portal venous hemodynamics together with partial lowering of portal venous pressure and guaranteeing intrahepatic perfusion through right portal vein. It is also obviously to have postoperative prevention of shunt restenoses and lowering postoperative incidence of hepato-encephalopathy. (authors)

  13. Hemi-Intravascular Stenting for Supermicrosurgical Anastomosis

    Directory of Open Access Journals (Sweden)

    Kensuke Tashiro, MD

    2017-11-01

    Conclusions:. Hemi-IVaS could be a useful alternative to conventional intravascular stenting techniques and is also effective for supermicrosurgical perforator-to-perforator anastomosis. Further studies are needed to improve the success rate and to explore its other possible utilizations in supermicrosurgery.

  14. 3-Year Clinical Follow-Up of the RIBS IV Clinical Trial: A Prospective Randomized Study of Drug-Eluting Balloons Versus Everolimus-Eluting Stents in Patients With In-Stent Restenosis in Coronary Arteries Previously Treated With Drug-Eluting Stents.

    Science.gov (United States)

    Alfonso, Fernando; Pérez-Vizcayno, María José; Cuesta, Javier; García Del Blanco, Bruno; García-Touchard, Arturo; López-Mínguez, José Ramón; Masotti, Mónica; Zueco, Javier; Cequier, Angel; Velázquez, Maite; Moreno, Raúl; Mainar, Vicente; Domínguez, Antonio; Moris, Cesar; Molina, Eduardo; Rivero, Fernando; Jiménez-Quevedo, Pilar; Gonzalo, Nieves; Fernández-Pérez, Cristina

    2018-05-28

    This study sought to compare the long-term safety and efficacy of drug-eluting balloons (DEB) and everolimus-eluting stents (EES) in patients with in-stent restenosis (ISR) of drug-eluting stents (DES). Treatment of patients with DES-ISR remains a challenge. The RIBS IV (Restenosis Intra-Stent of Drug-Eluting Stents: Drug-Eluting Balloons vs Everolimus-Eluting Stents) trial is a prospective multicenter randomized clinical trial comparing DEB and EES in patients with DES-ISR. The pre-specified comparison of the 3-year clinical outcomes obtained with these interventions is the main objective of the present study. A total of 309 patients with DES-ISR were randomized to DEB (n = 154) or EES (n = 155). At angiographic follow-up, the in-segment minimal lumen diameter was larger in the EES arm (2.03 ± 0.7 mm vs. 1.80 ± 0.6 mm; p 1 year) target lesion revascularization (2.6% vs. 4%) and target vessel revascularization (4% vs. 6.6%) was similar in the 2 arms. Rates of cardiac death (3.9% vs. 3.2%), myocardial infarction (2.6% vs. 4.5%), and stent thrombosis (1.3% vs. 2.6%) at 3 years were also similar in both arms. The 3-year clinical follow-up of this randomized clinical trial demonstrates that in patients with DES-ISR, EES reduce the need for repeat interventions compared with DEB. (Restenosis Intra-Stent of Drug-Eluting Stents: Drug-Eluting Balloons vs Everolimus-Eluting Stents [RIBS IV]; NCT01239940). Published by Elsevier Inc.

  15. The outcome of extracorporeal shockwave lithotripsy for renal pelvic stone with and without JJ stent--a comparative study.

    Science.gov (United States)

    Mohayuddin, Nazim; Malik, Hamad Afzal; Hussain, Manzoor; Tipu, Salman Ahmed; Shehzad, Asad; Hashmi, Altaf; Naqvi, Syed Ali Anwar; Rizvi, Syed Adibul Hasan

    2009-03-01

    To compare the outcome of Extra corporeal shockwave lithotripsy for a renal pelvic stone with and without JJ stent. A comparative cross sectional study was carried out at Sindh Institute of Urology and Transplantation from January 2007 to January 2008. Eighty patients with renal pelvic stone measuring 2cm +/- 2mm were selected for treatment with Extra Corporeal Shockwave Lithotripsy (ESWL). All of these patients were adults with normal renal function and had unilateral renal stones with negative urine cultures. Patients with renal failure and children were excluded. They were divided into two groups of 40 each. Group A patients underwent ESWL without a JJ stent and in Group B a JJ stent was placed before ESWL. SLX F2 electromagnetic ESWL machine was used to impart shock waves. 3000 shockwaves were given in a session. Both the groups were compared for renal colic, steinstrasse, fever, lower urinary tract symptoms (LUTS) emergency room visits and hospital admissions, stone clearance, number of ESWL sessions, auxilliary procedures, (percutaneous nephrostomy or ureterorenoscopy) and cost. Ureteric colic occurred in 13 (32.5%) patients in group A and in 3 (7.5%) patient in group B. Steinstrasse developed in 4 (10%) patients with out JJ stent and in 3 (7.5%) patients with JJ stent. Fever was encountered in 1 (2.5%) patient in group A and in 3 (7.5%) patient in group B. Mean emergency room visits were 2.1 per patient in group A and 0.7 per patient in group B. Stone clearance occurred in 33 (82.5%) patients in group A and 31 (77.5%) in group B. In group B lower urinary tract symptoms were found in 50% versus 20% in group A. Auxillary procedure was performed in one (2.5%) patient each in both groups. Pre ESWL JJ stenting for a 2 cm +/- 2 mm renal stone was not beneficial in terms of steinstrasse, fever, stone clearance and number of ESWL sessions. However ureteric colic was significantly less in the stented group. Lower urinary tract symptoms (LUTS) was also significantly

  16. Clinical Study on Using 125I Seeds Articles Combined with Biliary Stent Implantation in the Treatment of Malignant Obstructive Jaundice.

    Science.gov (United States)

    Wang, Tao; Liu, Sheng; Zheng, Yan-Bo; Song, Xue-Peng; Sun, Bo-Lin; Jiang, Wen-Jin; Wang, Li-Gang

    2017-08-01

    Aim: To study the feasibility and curative effect of 125 I seeds articles combined with biliary stent implantation in the treatment of malignant obstructive jaundice. Patients and Methods: Fifty patients with malignant obstructive jaundice were included. Twenty-four were treated by biliary stent implantation combined with intraluminal brachytherapy by 125 I seeds articles as the experimental group, while the remaining 26 were treated by biliary stent implantation only as the control group. The goal of this study was to evaluate total bilirubin, direct bilirubin and tumor markers (cancer antigen (CA)-199, CA-242 and carcinoembryonic antigen (CEA)), as well as biliary stent patency status and survival time before and after surgery. Results: Jaundice improved greatly in both groups. The decreases of CA-199 and CA-242 had statistical significance (p=0.003 and p=0.004) in the experimental group. The ratio of biliary stent patency was 83.3% (20/24) in the experimental group and 57.7% (15/26) in the control group (p=0.048). The biliary stent patency time in the experimental group was 1~15.5 (mean=9.84) months. The biliary stent patency time in the control group was 0.8~9 (mean=5.57) months, which was statistically significant (p=0.018). The median survival time was 10.2 months in the experimental group, while 5.4 months in control group (pjaundice possibly by inhibiting the proliferation of vascular endothelial cells and the growth of tumor. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  17. In-vitro study on the accuracy of a simple-design CT-guided stent for dental implants

    International Nuclear Information System (INIS)

    Huh, Young June; Choi, Bo Ram; Huh, Kyung Hoe; Yi, Won Jin; Heo, Min Suk; Lee, Sam Sun; Choi, Soon Chul

    2012-01-01

    An individual surgical stent fabricated from computed tomography (CT) data, called a CT-guided stent, would be useful for accurate installation of implants. The purpose of the present study was to introduce a newly developed CT-guided stent with a simple design and evaluate the accuracy of the stent placement. A resin template was fabricated from a hog mandible and a specially designed plastic plate, with 4 metal balls inserted in it for radiographic recognition, was attached to the occlusal surface of the template. With the surgical stent applied, CT images were taken, and virtual implants were placed using software. The spatial positions of the virtually positioned implants were acquired and implant guiding holes were drilled into the surgical stent using a specially designed 5-axis drilling machine. The surgical stent was placed on the mandible and CT images were taken again. The discrepancy between the central axis of the drilled holes on the second CT images and the virtually installed implants on the first CT images was evaluated. The deviation of the entry point and angulation of the central axis in the reference plane were 0.47±0.27 mm, 0.57±0.23 mm, and 0.64±0.16 degree, 0.57±0.15 degree, respectively. However, for the two different angulations in each group, the 20 degree angulation showed a greater error in the deviation of the entry point than did the 10 degree angulation. The CT-guided template proposed in this study was highly accurate. It could replace existing implant guide systems to reduce costs and effort.

  18. Metallic Stents for Tracheobronchial Pathology Treatment

    International Nuclear Information System (INIS)

    Serrano, Carolina; Laborda, Alicia; Lozano, Juan M.; Caballero, Hugo; Sebastián, Antonio; Lopera, Jorge; Gregorio, Miguel Ángel de

    2013-01-01

    Purpose: To present the 7-year experience of the treatment of benign and malignant tracheobronchial stenoses using metallic stents. Patients and Methods: One hundred twenty-three stents were inserted in 86 patients (74 benign and 12 malignant stenoses). Ninety-seven stents were placed in the trachea and 26 in the bronchi. The procedures were performed under fluoroscopic and flexible bronchoscopic guidance with the patient under light sedation. In cases of severe stenotic lesions or obstructions, laser resection was performed before stent placement. Clinical and functional pulmonary data were recorded before and 3 months after the procedure. Follow-up involved clinical data and radiographic techniques at 48 h and at 1-, 3-, 6-, and 12-month intervals. Results: The technical success was 100 %. Dyspnea disappearance, forced expiratory volume in the first second, and pulmonary functional data improvement was observed in all patients (p < 0.001). Complications were detected in 23 patients (26.7 %). Mean follow-up time was 6.3 ± 1.2 months in patients with malignant lesions and 76.2 ± 2.3 months patients with in benign lesions. By the end of the study, 100 % of patients with malignant pathology and 6.7 % of patients with benign lesions had died. Conclusion: Endoluminal treatment of tracheobronchial stenosis with metallic stents is a therapeutic alternative in patients who are poor candidates for surgery. In unresectable malignant lesions, the benefit of metallic stenting is unquestionable. In benign lesions, the results are satisfactory, but sometimes other interventions are required to treat complications. New stent technology may improve these results

  19. Metallic stents for tracheobronchial pathology treatment.

    Science.gov (United States)

    Serrano, Carolina; Laborda, Alicia; Lozano, Juan M; Caballero, Hugo; Sebastián, Antonio; Lopera, Jorge; de Gregorio, Miguel Ángel

    2013-12-01

    To present the 7-year experience of the treatment of benign and malignant tracheobronchial stenoses using metallic stents. One hundred twenty-three stents were inserted in 86 patients (74 benign and 12 malignant stenoses). Ninety-seven stents were placed in the trachea and 26 in the bronchi. The procedures were performed under fluoroscopic and flexible bronchoscopic guidance with the patient under light sedation. In cases of severe stenotic lesions or obstructions, laser resection was performed before stent placement. Clinical and functional pulmonary data were recorded before and 3 months after the procedure. Follow-up involved clinical data and radiographic techniques at 48 h and at 1-, 3-, 6-, and 12-month intervals. The technical success was 100 %. Dyspnea disappearance, forced expiratory volume in the first second, and pulmonary functional data improvement was observed in all patients (p < 0.001). Complications were detected in 23 patients (26.7 %). Mean follow-up time was 6.3 ± 1.2 months in patients with malignant lesions and 76.2 ± 2.3 months patients with in benign lesions. By the end of the study, 100 % of patients with malignant pathology and 6.7 % of patients with benign lesions had died. Endoluminal treatment of tracheobronchial stenosis with metallic stents is a therapeutic alternative in patients who are poor candidates for surgery. In unresectable malignant lesions, the benefit of metallic stenting is unquestionable. In benign lesions, the results are satisfactory, but sometimes other interventions are required to treat complications. New stent technology may improve these results.

  20. Metallic Stents for Tracheobronchial Pathology Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, Carolina, E-mail: carolina.serrano@unizar.es [University of Zaragoza, Surgical Pathology Unit, Animal Pathology Department (Spain); Laborda, Alicia, E-mail: alaborda@unizar.es [University of Zaragoza, Minimally Invasive Techniques Research Group (GITMI) (Spain); Lozano, Juan M., E-mail: juamauloz@gmail.com [Marly Clinic, Radiology Department (Colombia); Caballero, Hugo, E-mail: hugocaballero2007@gmail.com [Marly Clinic, Pulmonology Department (Colombia); Sebastian, Antonio, E-mail: antonio.sebastian@ono.es [Lozano Blesa Clinical University Hospital, Pulmonology Department (Spain); Lopera, Jorge, E-mail: lopera@uthscsa.edu [Health Science Center, Interventional Radiology Deparment (United States); Gregorio, Miguel Angel de, E-mail: mgregori@unizar.es [University of Zaragoza, Minimally Invasive Techniques Research Group (GITMI) (Spain)

    2013-12-15

    Purpose: To present the 7-year experience of the treatment of benign and malignant tracheobronchial stenoses using metallic stents. Patients and Methods: One hundred twenty-three stents were inserted in 86 patients (74 benign and 12 malignant stenoses). Ninety-seven stents were placed in the trachea and 26 in the bronchi. The procedures were performed under fluoroscopic and flexible bronchoscopic guidance with the patient under light sedation. In cases of severe stenotic lesions or obstructions, laser resection was performed before stent placement. Clinical and functional pulmonary data were recorded before and 3 months after the procedure. Follow-up involved clinical data and radiographic techniques at 48 h and at 1-, 3-, 6-, and 12-month intervals. Results: The technical success was 100 %. Dyspnea disappearance, forced expiratory volume in the first second, and pulmonary functional data improvement was observed in all patients (p < 0.001). Complications were detected in 23 patients (26.7 %). Mean follow-up time was 6.3 {+-} 1.2 months in patients with malignant lesions and 76.2 {+-} 2.3 months patients with in benign lesions. By the end of the study, 100 % of patients with malignant pathology and 6.7 % of patients with benign lesions had died. Conclusion: Endoluminal treatment of tracheobronchial stenosis with metallic stents is a therapeutic alternative in patients who are poor candidates for surgery. In unresectable malignant lesions, the benefit of metallic stenting is unquestionable. In benign lesions, the results are satisfactory, but sometimes other interventions are required to treat complications. New stent technology may improve these results.

  1. Primary and revision efficacy of cross-wired metallic stents for endoscopic bilateral stent-in-stent placement in malignant hilar biliary strictures.

    Science.gov (United States)

    Lee, T H; Moon, J H; Kim, J H; Park, D H; Lee, S S; Choi, H J; Cho, Y D; Park, S H; Kim, S J

    2013-01-01

    Endoscopic bilateral drainage for inoperable malignant hilar biliary strictures (HBS) using metal stents is considered to be technically difficult. Furthermore, endoscopic revision of bilateral stenting after occlusion can be challenging. This study was performed to evaluate the long-term efficacy of endoscopic bilateral stent-in-stent placement of cross-wired metallic stents in high-grade malignant HBS and planned endoscopic bilateral revision. A total of 84 patients with inoperable high-grade malignant HBS were enrolled from three academic tertiary referral centers. Two cross-wired metal stents were inserted using a bilateral stent-in-stent placement method. Bilateral endoscopic revision was also performed during follow-up using either identical metal stents or plastic stents. The main outcome measurements were technical and functional success, complications, stent patency, and endoscopic revision efficacy. The technical and clinical success rates of endoscopic bilateral stent-in-stent placement of cross-wired metallic stents were 95.2% (80/84) and 92.9% (78/84), respectively. Median patency (range) and survival were 238 days (10-429) and 256 days (10-1130), respectively. Obstruction of primary bilateral stents occurred in 30.8% (24/78) of patients with functionally successful stent placement. The technical and clinical success rates of planned bilateral endoscopic revision for occluded stents were 83.3% (20/24) and 79.2% (19/24), respectively. For revision, bilateral metallic stents were placed in 11 patients (55.0%); the remaining patients received plastic stents. Palliative endoscopic bilateral stent-in-stent placement of cross-wired metallic stents was effective in patients with inoperable HBS. Revision endoscopic bilateral stenting may be feasible and successful in cases where the primary deployed metal stents are occluded. © Georg Thieme Verlag KG Stuttgart · New York.

  2. First-in-man study of simvastatin-eluting stent in de novo coronary lesions: the SIMVASTENT study.

    Science.gov (United States)

    Zago, Alexandre C; Matte, Bruno S; Reginato, Luciana; Iturry-Yamamoto, Germán; Krepsky, Ana; Bergoli, Luiz Carlos C; Balvedi, Julise; Raudales, José C; Saadi, Eduardo K; Zago, Alcides J

    2012-01-01

    Statins have anti-inflammatory and antiproliferative properties irrespective of their cholesterol-lowering effects. The aim of the present study was to evaluate a simvastatin-eluting stent (SimvES) in the treatment of de novo coronary lesions. Forty-two patients with de novo coronary artery lesions were assigned to SimvES, bare-metal stent (BMS) or everolimus-eluting stent (EES) implantation followed by intravascular ultrasound (IVUS) for neointimal quantitative analysis. Six months later, quantitative coronary angiography (QCA) and IVUS were repeated. QCA showed no binary restenosis, a mean in-stent late loss of 1.05 ± 0.25 mm (BMS, 1.12 ± 0.48 mm; EES, 0.20 ± 0.16 mm) and a diameter stenosis of 33.5 ± 7.1% (BMS, 35.5 ± 15.30%; EES, 7.2 ± 3.12%). Control IVUS showed a mean in-stent obstruction of 18.3 ± 9.4% (BMS, 32.8 ± 19.1%; EES, 9.8 ± 2.4%) and a neointimal volume index of 1.58 ± 0.75 mm(3)/mm (BMS, 2.93 ± 1.76 mm(3)/mm; EES, 0.80 ± 0.16 mm(3)/mm). Thrombus, late incomplete apposition and major adverse cardiac events were not observed. In this sample of patients with de novo coronary lesions, the use of a SimvES was not related to major adverse cardiac events, but it was associated with a higher level of neointimal proliferation than expected.

  3. Expandable esophageal metallic stents coating with silicone rubber: An experimental study in rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ho Young; Han, Young Min; Son, Myung Hee; Kim, Jong Soo; Choi, Ki Chul; Kuh, Ja Hong; Chae, Soo Wan [Chonbuk National University Medical School, Chonju (Korea, Republic of); Kim, Hak Nam [Chungju Lee Rha Hospital, Chungju (Korea, Republic of)

    1990-10-15

    To determine the effect of the expandable esophageal metallic stents on the esophagus, we constructed an expandable metallic stent. It was stainless steel wire formed in a zig-zag pattern in fully expanded diameter. Twenty stents were introduced in the normal esophagus through a 8.5 French-teflon sheath in 10 rabbits for 1 week to 12 weeks. Three out of the 20 stents migrated slightly. At 1 week after the placement of the stent, the mucosa partly revealed pressure necrosis and some regeneration, the muscle layer below the stent wires found compressed and thinned. At 8 weeks, the mucosa showed complete regeneration, and the stent wires were found covered by fibrous tissue.

  4. Impact of sirolimus-eluting stent fractures without early cardiac events on long-term clinical outcomes: A multislice computed tomography study

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Tsuyoshi [Toyohashi Heart Center, Oyama-cho, Toyohashi (Japan); Nagoya City University Graduate School of Medical Sciences, Department of Cardio-Renal Medicine and Hypertension, Nagoya (Japan); Kimura, Masashi; Ehara, Mariko; Terashima, Mitsuyasu; Nasu, Kenya; Kinoshita, Yoshihisa; Habara, Maoto; Tsuchikane, Etsuo; Suzuki, Takahiko [Toyohashi Heart Center, Oyama-cho, Toyohashi (Japan)

    2014-05-15

    This study sought to evaluate the impact of sirolimus-eluting stent (SES) fractures on long-term clinical outcomes using multislice computed tomography (MSCT). In this study, 528 patients undergoing 6- to 18-month follow-up 64-slice MSCT after SES implantation without early clinical events were followed clinically (the median follow-up interval was 4.6 years). A CT-detected stent fracture was defined as a complete gap with Hounsfield units (HU) <300 at the site of separation. The major adverse cardiac events (MACEs), including cardiac death, stent thrombosis, and target lesion revascularisation, were compared according to the presence of stent fracture. Stent fractures were observed in 39 patients (7.4 %). MACEs were more common in patients with CT-detected stent fractures than in those without (46 % vs. 7 %, p < 0.01). Univariate Cox regression analysis indicated a significant relationship between MACE and stent fracture [hazard ratio (HR) 7.65; p < 0.01], age (HR 1.03; p = 0.04), stent length (HR 1.03; p < 0.01), diabetes mellitus (HR 1.77; p = 0.04), and chronic total occlusion (HR 2.54; p = 0.01). In the multivariate model, stent fracture (HR 5.36; p < 0.01) and age (HR 1.03; p = 0.04) remained significant predictors of MACE. An SES fracture detected by MSCT without early clinical events was associated with long-term clinical adverse events. (orig.)

  5. SU-E-T-115: Dose Perturbation Study of Self-Expandable Metal and Polyester Esophageal Stents in Proton Therapy Beams

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S; Li, Z [University of Florida Proton Therapy Institute, Jacksonville, FL (United States); Jalaj, S; McGaw, C; B K, John; J S, Scolapio; J C, Munoz [Division of Gastoenterology, Department of Medicine, University of Florida, Jacksonville, FL (United States)

    2014-06-01

    Purpose: This work investigates dose perturbations due to Self-expandable metal and polyester esophageal stents undergoing proton radiotherapy for esophageal cancer. Methods: Five commercially available esophageal stents made of nitinol (Evolution, Wallflex and Ultraflex), stainless steel (Z-Stent) and polyester (Polyflex) were tested. Radiochromic film (GafChromic EBT3 film, Ashland, Covington, KY) wrapped around a stent and a 12cc syringe was irradiated with 2CGE (Cobalt Gray Equivalent) of proton beam in a custom fabricated acrylic phantom. An air-hollow syringe simulates the esophagus. Results: The Z-stent created the largest dose perturbations ranges from -14.5% to 6.1% due to the steel composition. The WallFlex, Evolution and Ultraflex stents produced the dose perturbation ranges of (−9.2%∼8.6%), (−6.8%∼5.7%) and (−6.2%∼6.2%), respectively. The PolyFlex stent contains the radiopaque tungsten markers located top, middle and bottom portions. When the focal cold spots induced by the markers were excluded in the analysis, the dose perturbation range was changed from (−11.6%∼6.4%) to (−0.6%∼5.0%). Conclusion: The magnitude of dose perturbation is related to material of a metallic stent. The non-metallic stent such as PolyFlex shows relatively lower dose perturbation than metallic stents except a radiopaque marker region. Overall Evolution and Ultraflex stent appear to be less dose perturbations. The largest dose perturbations (cold spots) were located at both edges of stents in distal area for the single proton beam irradiation study. The analysis of more than two proton beam which is more typical clinical beam arrangement would be necessary to minimize the doe perturbation effect in proton ratiotherapy.

  6. Quantification of in-stent restenosis parameters in rabbits by micro-CT

    International Nuclear Information System (INIS)

    Langheinrich, A.C.; Zoerb, C.; Jajima, J.; Lommel, D.; Rau, W.S.; Walker, G.; Mueller, K.M.; Bohle, R.M.

    2005-01-01

    Purpose: The well-defined model of angioplasty and stent implantation in the rabbit aorta is useful in experimental studies of restenosis. This study was performed to evaluate the feasibility of Micro-CT for quantification of in-stent restenosis in a rabbit aortic in-stent restenosis model. Material and Methods: To induce in-stent restenosis seven female New Zealand rabbits underwent balloon dilation and denudation prior to stenting the abdominal aorta. After six weeks on atherogenic diet, animals were killed and the aorta was perfused with contrast agent. Micro-CT morphometric analysis of balloon and stent injured arteries obtained by 700 transverse sections (voxel size 10 μm) was compared to conventional histological analysis. Results: Intimal hyperplasia was present in stented and balloon injured arteries with a moderate intimal area assessed by Micro-CT and conventional histology (3.91±0.5 mm 2 vs. 4.18±0.42; r=0.9). High significant correlations between Micro-CT image analysis and conventional histomorphometry were obtained for lesion size, size of media, size of lumen and stent area (r=0.84 to 0.96). Conclusion: Micro-CT is feasible for quantitative information about restenosis following balloon angioplasty and stent implantation and has the potential to become a standard technique in many laboratories which will augment serial histology as the reference method for ex-vivo studies of restenosis. (orig.)

  7. A systematic review and meta-analysis of randomized trials and prospective studies comparing covered and bare self-expandable metal stents for the treatment of malignant obstruction in the digestive tract.

    Science.gov (United States)

    Yang, Zhiping; Wu, Qiong; Wang, Fang; Ye, Xiaofei; Qi, Xingshun; Fan, Daiming

    2013-01-01

    Self-expandable metal stents (SEMS) are widely used for the palliative treatment of malignant gastrointestinal obstruction. Our aim was to evaluate the evidence comparing covered and bare SEMS in the digestive tract using meta-analytical techniques. A literature search was performed using PubMed, Cochrane Library, and Embase databases for comparative studies assessing the two types of stents. The primary outcomes of interest were stent patency and patient survival; second outcomes included technical success, clinical success, tumor ingrowth, tumor overgrowth, and stent migration. A random-effects model was conducted. Pooled analysis was done separately based on the different segments of the digestive tract. Eleven studies (8 randomized controlled trials and 3 prospective cohort studies) including a total of 1376 patients were identified. Covered SEMS were equivalent to bare SEMS in terms of technical success, clinical success, stent patency (gastroduodenal obstruction: HR =0.87, 95% CI 0.53-1.42; colorectal obstruction: HR =0.89, 95% CI 0.18-4.45; biliary obstruction: HR =0.73, 95% CI 0.41-1.32) and survival rates (esophageal obstruction: HR =1.80, 95% CI 0.73-4.44; gastroduodenal obstruction: HR =0.83, 95% CI 0.55-1.26; biliary obstruction: HR =0.99, 95% CI 0.77-1.28), although bare stents were more prone to tumor ingrowth (esophageal obstruction: RR =0.10, 95% CI 0.01-0.77; gastroduodenal obstruction: RR =0.12, 95% CI 0.03-0.55; colorectal obstruction: RR =0.21, 95% CI 0.06-0.70; biliary obstruction: RR =0.21, 95% CI 0.06-0.69), whereas covered stents had the higher risk of stent migration (gastroduodenal obstruction: RR =5.01, 95% CI 1.53-16.43; colorectal obstruction: RR =11.70, 95% CI 2.84-48.27; biliary obstruction: RR =8.11, 95% CI 1.47-44.76) and tumor overgrowth (biliary obstruction: RR =2.03, 95% CI 1.08-3.78). Both covered and bare SEMS are comparable in efficacy for the palliative treatment of malignant obstruction in the digestive tract. Each type of

  8. Airway stents

    Science.gov (United States)

    Keyes, Colleen

    2018-01-01

    Stents and tubes to maintain the patency of the airways are commonly used for malignant obstruction and are occasionally employed in benign disease. Malignant airway obstruction usually results from direct involvement of bronchogenic carcinoma, or by extension of carcinomas occurring in the esophagus or the thyroid. External compression from lymph nodes or metastatic disease from other organs can also cause central airway obstruction. Most malignant airway lesions are surgically inoperable due to advanced disease stage and require multimodality palliation, including stent placement. As with any other medical device, stents have significantly evolved over the last 50 years and deserve an in-depth understanding of their true capabilities and complications. Not every silicone stent is created equal and the same holds for metallic stents. Herein, we present an overview of the topic as well as some of the more practical and controversial issues surrounding airway stents. We also try to dispel the myths surrounding stent removal and their supposed use only in central airways. At the end, we come to the long-held conclusion that stents should not be used as first line treatment of choice, but after ruling out the possibility of curative surgical resection or repair. PMID:29707506

  9. Acute thrombosis during left main stenting using tap technique in a patient presenting with non-ST-segment elevation acute coronary syndrome

    International Nuclear Information System (INIS)

    Natarajan, Deepak

    2015-01-01

    This case reports the sudden development of large burden of thrombi in the left anterior descending coronary artery immediately following distal left main stenting using TAP technique in a middle aged man who presented with non ST-segment elevation acute coronary syndrome despite having been administered 7,500 units of unfractionated heparin and being given 325 mg of aspirin and 60 mg of prasugrel prior to the procedure. The thrombi were managed effectively by giving an intra-coronary high bolus dose of tirofiban (25 mcg/kg) without the need for catheter thrombus extraction. Tirofiban intra-venous infusion was maintained for 18 hours, and the patient was discharged in stable condition on the third day. Importantly there is no controlled study on upstream administration of glycoprotein IIb/IIIa inhibitors in addition to the newer more potent anti-platelet agents in patients with unprotected distal left main disease presenting with non ST-segment elevation acute coronary syndrome, nor is there any data on safety and efficacy of mandatory usage of injectable anti-platelet agents at the start of a procedure in a catheterization laboratory in such a setting

  10. Acute thrombosis during left main stenting using tap technique in a patient presenting with non-ST-segment elevation acute coronary syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Natarajan, Deepak, E-mail: deepaknatarajan@me.com

    2015-06-15

    This case reports the sudden development of large burden of thrombi in the left anterior descending coronary artery immediately following distal left main stenting using TAP technique in a middle aged man who presented with non ST-segment elevation acute coronary syndrome despite having been administered 7,500 units of unfractionated heparin and being given 325 mg of aspirin and 60 mg of prasugrel prior to the procedure. The thrombi were managed effectively by giving an intra-coronary high bolus dose of tirofiban (25 mcg/kg) without the need for catheter thrombus extraction. Tirofiban intra-venous infusion was maintained for 18 hours, and the patient was discharged in stable condition on the third day. Importantly there is no controlled study on upstream administration of glycoprotein IIb/IIIa inhibitors in addition to the newer more potent anti-platelet agents in patients with unprotected distal left main disease presenting with non ST-segment elevation acute coronary syndrome, nor is there any data on safety and efficacy of mandatory usage of injectable anti-platelet agents at the start of a procedure in a catheterization laboratory in such a setting.

  11. Prognostic value of renal fractional flow reserve in blood pressure response after renal artery stenting (PREFER study).

    Science.gov (United States)

    Kądziela, Jacek; Januszewicz, Andrzej; Prejbisz, Aleksander; Michałowska, Ilona; Januszewicz, Magdalena; Florczak, Elżbieta; Kalińczuk, Łukasz; Norwa-Otto, Bożena; Warchoł, Ewa; Witkowski, Adam

    2013-01-01

    The aim of our study was to determine a potential relationship between resting translesional pressures ratio (Pd/Pa ratio), renal fractional flow reserve (rFFR) and blood pressure response after renal artery stenting. Thirty five hypertensive patients (49% males, mean age 64 years) with at least 60% stenosis in angiography, underwent renal artery stenting. Translesional systolic pressure gradient (TSPG), Pd/Pa ratio (the ratio of mean distal to lesion and mean proximal pressures) and hyperemic rFFR - after intrarenal administration of papaverine - were measured before stent implantation. Ambulatory blood pressure measurements (ABPM) were recorded before the procedure and after 6 months. The ABPM results were presented as blood pressure changes in subgroups of patients with normal (≥ 0.9) vs. abnormal (renal artery stenting. Median changes of 24-h systolic/diastolic blood pressure were comparable in patients with abnormal vs. normal Pd/Pa ratio (-4/-3 vs. 0/2 mm Hg; p = NS) and with abnormal vs. normal rFFR (-2/-1 vs. -2/-0.5 mm Hg, respectively). Physiological assessment of renal artery stenosis using Pd/Pa ratio and papaverine- induced renal fractional fl ow reserve did not predict hypertension response after renal artery stenting.

  12. Self-expandable metal stents for malignant esophageal obstruction: a comparative study between extrinsic and intrinsic compression.

    Science.gov (United States)

    Rhee, K; Kim, J-H; Jung, D H; Han, J W; Lee, Y C; Lee, S K; Shin, S K; Park, J C; Chung, H S; Park, J J; Youn, Y H; Park, H

    2016-04-01

    Self-expandable metal stents (SEMSs) are effective for malignant esophageal obstruction, but usefulness of SEMSs in extrinsic lesions is yet to be elucidated. This study is aimed at evaluating the clinical usefulness of SEMSs in the extrinsic compression compared with intrinsic. A retrospective review was conducted for 105 patients (intrinsic, 85; extrinsic, 20) with malignant esophageal obstruction who underwent endoscopic SEMSs placement. Technical and clinical success rates were evaluated and clinical outcomes were compared between extrinsic and intrinsic group. Extrinsic group was mostly pulmonary origin. Overall technical and clinical success rate was 100% and 91%, respectively, without immediate complications. Extrinsic and intrinsic group did not differ significantly in clinical success rate. The median stent patency time was 131.3 ± 85.8 days in intrinsic group while that of extrinsic was 54.6 ± 45.1 due to shorter survival after stent insertion. The 4-, 8-, and 12-week patency rates were 90.5%, 78.8%, and 64.9% respectively in intrinsic group, while stents of extrinsic group remained patent until death. Uncovered, fully covered, and double-layered stent were used evenly and the types did not influence patency in both groups. In conclusion, esophageal SEMSs can safely and effectively be used for malignant extrinsic compression as well as intrinsic. © 2015 International Society for Diseases of the Esophagus.

  13. Tamsulosin, Solifenacin, and Their Combination for the Treatment of Stent-Related Symptoms: A Randomized Controlled Study.

    Science.gov (United States)

    Dellis, Athanasios E; Papatsoris, Athanasios G; Keeley, Francis X; Bamias, Aristotelis; Deliveliotis, Charalambos; Skolarikos, Andreas A

    2017-01-01

    To properly use the Ureteric Symptom Score Questionnaire (USSQ) to evaluate, in a randomized control study, the effect of tamsulosin, solifenacin, and their combination in improving symptoms and quality of life in patients with indwelling ureteral stents. After institutional review board approval, 260 patients with a ureteral stent were randomly assigned to receive tamsulosin 0.4 mg, solifenacin 5 mg, or placebo and further randomized to receive their combination. The validated USSQ was completed 1 and 4 weeks after stent insertion and 4 weeks after stent removal. Kruskal-Wallis test, chi-squared test (or Fisher's exact test), one-way analysis of variance, and T-test (or Wilcoxon rank-sum test if not normal data) were used for statistical analysis. The results were considered significant at p tamsulosin or solifenacin expressed significantly lower urinary (p tamsulosin and solifenacin alone or in combination, improves stent-related symptoms and has a positive impact on quality of life.

  14. A shape memory airway stent for tracheobronchomalacia in children: an experimental and clinical study.

    Science.gov (United States)

    Tsugawa, C; Nishijima, E; Muraji, T; Yoshimura, M; Tsubota, N; Asano, H

    1997-01-01

    The authors have designed a coil airway stent using a thermal shape-memory titanium-nickel alloy (SMA) to relieve airway collapse in children. A characteristic of alloy allowed the stent to be enclosed in the thin introducer tube and to position it bronchoscopically in the collapsed airway. When the stent is warmed to 37 to 40 degrees C, it expands to the memorized diameter and stents the airway. In eight rabbits, an experimental model of potentially fatal tracheomalacia was created by fracturing the tracheal cartilages. The stents of 6 mm in diameter and 15 mm in length were placed, and then the stents were recovered to their original shape within 1 minute. All rabbits except one showed no respiratory symptoms during the follow-up period. Results of bronchoscopy performed 6 and 10 months after implantation showed satisfactory patency of the trachea. The rabbits were killed for histological evaluation 6 to 28 months after implantation. The specimens showed little proliferation of granulation and no dislodgement of the stents. This procedure was attempted in two children who had severe bronchomalacia. One 5-year-old patient underwent implantation with a stent of 5 mm in diameter and 25 mm in length into the left main bronchus. The patient was relieved from apneic attacks. The stent was removed 2 years after implantation after a remarkable improvement of ventilation. The other patient with left bronchomalacia, age 1 year 2 months, underwent implantation with a 5-mm x 20-mm stent. The animal experiment and clinical experience indicated that (1) this stent can be easily inserted and removed bronchoscopically, (2) the stent has good tissue compatibility and little interference of mucociliary function, and (3) the SMA stent is a promising therapeutic adjunct in the management of children with severe tracheobronchomalacia.

  15. Clinical impact and risk stratification of balloon angioplasty for femoropopliteal disease in nitinol stenting era: Retrospective multicenter study using propensity score matching analysis

    Directory of Open Access Journals (Sweden)

    Taketsugu Tsuchiya

    2016-07-01

    Full Text Available Objective: Nitinol stenting could bring the better outcome in endovascular therapy for femoropopliteal disease. However, it might be expected that recent marked advances in both device technology and operator technique had led to improved efficacy of balloon angioplasty even in this segment. The aims of this study were to evaluate the clinical impact of balloon angioplasty for femoropopliteal disease and make risk stratification clear by propensity score matching analysis. Methods: Based on the multicenter retrospective data, 2758 patients (balloon angioplasty: 729 patients and nitinol stenting: 2029 patients, those who underwent endovascular therapy for femoropopliteal disease, were analyzed. Results: The propensity score matching procedure extracted a total of 572 cases per group, and the primary patency rate of balloon angioplasty and nitinol stenting groups after matching was significantly the same (77.2% vs 82.7% at 1 year; 62.2% vs 64.3% at 3 years; 47.8% vs 54.3% at 5 years. In multivariate Cox hazard regression analysis, significant predictors for primary patency were diabetes mellitus, regular dialysis, cilostazol use, chronic total occlusion, and intra-vascular ultra-sonography use. The strategy of balloon angioplasty was not evaluated as a significant predictor for the primary patency. After risk stratification using five items (diabetes mellitus, regular dialysis, no use of intra-vascular ultra-sonography, chronic total occlusion, and no use of cilostazol: the DDICC score, the estimated primary patency rates of each group (low, DDICC score 0–2; moderate, DDICC score 3; high risk, DDICC score 4–5 were 88.6%, 78.3%, and 63.5% at 1 year; 75.2%, 60.7%, and 39.8% at 3 years; and 66.0%, 47.1%, and 26.3% at 5 years (p < 0.0001. The primary patency rate of balloon angioplasty and nitinol stenting groups was significantly the same in each risk stratification. Conclusion: This study suggests that balloon angioplasty does

  16. Follow-up after stent insertion in the tracheobronchial tree: role of helical computed tomography in comparison with fiberoptic bronchoscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ferretti, G.R.; Kocier, M.; Calaque, O.; Coulomb, M. [Service Central de Radiologie et Imagerie Medicale, INSERM EMI 9924, CHU, BP 217, 38043, Grenoble Cedex 9 (France); Arbib, F.; Pison, C. [Departement de Medecine Aigue Specialisee (DMAS), CHU Grenoble, CHU, BP 217, 38043, Grenoble Cedex 9 (France); Righini, C. [Service d' Oto Rhino Laryngologie, CHU Grenoble, BP 217, 38043, Grenoble Cedex 9 (France)

    2003-05-01

    The aim of this study was to compare helical CT with fiberoptic bronchoscopy findings to appraise the medium-term results of proximal-airways stenting. Twenty-five patients with 28 endobronchial metallic stents inserted for local advanced malignancy (n=13) or benign diseases (n=12) underwent follow-up CT from 3 days to 50 months (mean 8 months). All studies were obtained using helical CT with subsequent multiplanar reformation and three-dimensional reconstruction including virtual bronchoscopy. The location, shape, and patency of stents and adjacent airway were assessed. The results of CT were compared with the results of fiberoptic bronchoscopy obtained with a mean delay of 2.5 days (SD 9 days) after CT scan. Twelve stents (43%) remained in their original position, patent and without deformity. Sixteen stents were associated with local complications: migration (n=6); external compression with persistent stenosis (n=4); local recurrence of malignancy (n=4); fracture (n=1); and non-congruence between the airway and the stent (n=1). The CT demonstrated all the significant abnormalities demonstrated at fiberoptic bronchoscopy except two moderate stenoses (20%) related to granulomata at the origin of the stent. Ten of 14 stents inserted for benign conditions were without complications as compared with 2 of 14 in malignant conditions (p=0.008). Computed tomography is an accurate noninvasive method for evaluating endobronchial stents. The CT is a useful technique for follow-up of patients who have undergone endobronchial stenting. (orig.)

  17. Follow-up after stent insertion in the tracheobronchial tree: role of helical computed tomography in comparison with fiberoptic bronchoscopy

    International Nuclear Information System (INIS)

    Ferretti, G.R.; Kocier, M.; Calaque, O.; Coulomb, M.; Arbib, F.; Pison, C.; Righini, C.

    2003-01-01

    The aim of this study was to compare helical CT with fiberoptic bronchoscopy findings to appraise the medium-term results of proximal-airways stenting. Twenty-five patients with 28 endobronchial metallic stents inserted for local advanced malignancy (n=13) or benign diseases (n=12) underwent follow-up CT from 3 days to 50 months (mean 8 months). All studies were obtained using helical CT with subsequent multiplanar reformation and three-dimensional reconstruction including virtual bronchoscopy. The location, shape, and patency of stents and adjacent airway were assessed. The results of CT were compared with the results of fiberoptic bronchoscopy obtained with a mean delay of 2.5 days (SD 9 days) after CT scan. Twelve stents (43%) remained in their original position, patent and without deformity. Sixteen stents were associated with local complications: migration (n=6); external compression with persistent stenosis (n=4); local recurrence of malignancy (n=4); fracture (n=1); and non-congruence between the airway and the stent (n=1). The CT demonstrated all the significant abnormalities demonstrated at fiberoptic bronchoscopy except two moderate stenoses (20%) related to granulomata at the origin of the stent. Ten of 14 stents inserted for benign conditions were without complications as compared with 2 of 14 in malignant conditions (p=0.008). Computed tomography is an accurate noninvasive method for evaluating endobronchial stents. The CT is a useful technique for follow-up of patients who have undergone endobronchial stenting. (orig.)

  18. The Effect of Stent Cell Geometry on Carotid Stenting Outcomes

    Energy Technology Data Exchange (ETDEWEB)

    Alparslan, Burcu, E-mail: burcu.alparslan@gmail.com [Yozgat State Hospital, Radiology Clinic (Turkey); Nas, Omer Fatih, E-mail: omerfatihnas@gmail.com [Uludag University Faculty of Medicine, Department of Radiology (Turkey); Eritmen, Ulku Turpcu, E-mail: drulkutur@hotmail.com.tr [Special Eregli Anatolia Hospital, Radiology Clinic (Turkey); Duran, Selcen, E-mail: selcenduran16@hotmail.com [Yerkoy State Hospital, Neurology Clinic (Turkey); Ozkaya, Guven, E-mail: ozkaya@uludag.edu.tr [Uludag University Faculty of Medicine, Department of Biostatistics (Turkey); Hakyemez, Bahattin, E-mail: bhakyemez@uludag.edu.tr [Uludag University Faculty of Medicine, Department of Radiology (Turkey)

    2016-04-15

    PurposeThe aim of this study was to investigate the effect of stent cell geometry on midterm results of carotid artery stenting (CAS).Materials and MethodOne hundred fifty-five patients underwent CAS between February 2010 and December 2012. Ninety-one open- and 84 closed-cell stents were used in this non-randomized, retrospective study. Periprocedural complications were defined as the ones happened during the procedure or within 30 days afterwards. Starting from the 6th month after the procedure, in-stent restenosis was detected with multidetector computed tomography angiography and classified into four groups from focal restenosis to occlusion.ResultsEleven complications were encountered in the periprocedural period (four on the open- and seven on the closed-cell group). Total complication rate was 6.3 % (11/175). No significant difference was detected in terms of periprocedural complications between two groups (p = 0.643). There was statistically significant difference between stent design groups in regard to radiological findings (p = 0.002). Sixteen of open-cell stents and three of closed-cell stents had focal restenosis. One closed-cell stent had diffuse proliferative restenosis and one open-cell stent had total occlusion.ConclusionIn-stent restenosis was more common in open-cell stent group, which have larger free cell area than closed-cell stents. Although our radiologic findings promote us to use closed-cell design if ‘possible’, no difference was detected in terms of clinical outcomes.

  19. A pilot study and novel angiographic classification for superior sagittal sinus stenting in patients with non-thrombotic intracranial venous occlusive disease.

    Science.gov (United States)

    Raper, Daniel M S; Buell, Thomas J; Ding, Dale; Pomeraniec, I Jonathan; Crowley, R Webster; Liu, Kenneth C

    2018-01-01

    Safety and efficacy of superior sagittal sinus (SSS) stenting for non-thrombotic intracranial venous occlusive disease (VOD) is unknown. The aim of this retrospective cohort study is to evaluate outcomes after SSS stenting. We evaluated an institutional database to identify patients who underwent SSS stenting. Radiographic and clinical outcomes were analyzed and a novel angiographic classification of the SSS was proposed. We identified 19 patients; 42% developed SSS stenosis after transverse sinus stenting. Pre-stent maximum mean venous pressure (MVP) in the SSS of 16.2 mm Hg decreased to 13.1 mm Hg after stenting (p=0.037). Preoperative trans-stenosis pressure gradient of 4.2 mm Hg decreased to 1.5 mm Hg after stenting (pSSS stenosis distal to the stent construct was noted. Improvement in headache, tinnitus, and visual obscurations was reported by 66.7%, 63.6%, and 50% of affected patients, respectively, at mean follow-up of 5.2 months. We divided the SSS into four anatomically equal segments, numbered S1-S4, from the torcula to frontal pole. SSS stenosis typically occurs in the S1 segment, and the anterior extent of SSS stents was deployed at the S1-S2 junction in all but one case. SSS stenting is reasonably safe, may improve clinical symptoms, and significantly reduces maximum MVP and trans-stenosis pressure gradients in patients with VOD with SSS stenosis. The S1 segment is most commonly stenotic, and minimum pressure gradients for symptomatic SSS stenosis may be lower than for transverse or sigmoid stenosis. Additional studies and follow-up are necessary to better elucidate appropriate clinical indications and long-term efficacy of SSS stenting. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  20. Metallic ureteral stents in malignant ureteral obstruction: clinical factors predicting stent failure.

    Science.gov (United States)

    Chow, Po-Ming; Hsu, Jui-Shan; Huang, Chao-Yuan; Wang, Shuo-Meng; Lee, Yuan-Ju; Huang, Kuo-How; Yu, Hong-Jheng; Pu, Yeong-Shiau; Liang, Po-Chin

    2014-06-01

    To provide clinical outcomes of the Resonance metallic ureteral stent in patients with malignant ureteral obstruction, as well as clinical factors predicting stent failure. Cancer patients who have received Resonance stents from July 2009 to March 2012 for ureteral obstruction were included for chart review. Stent failure was detected by clinical symptoms, image studies, and renal function tests. Survival analysis for stent duration was used to estimate patency rate and factors predicting stent failure. A total of 117 stents were inserted successfully into 94 ureteral units in 79 patients. There were no major complications. These stents underwent survival analysis and proportional hazard regression. The median duration for the stents was 5.77 months. In multivariate analysis, age (P=0.043), preoperative serum creatinine level (P=0.0174), and cancer type (P=0.0494) were significant factors associated with stent failure. Cancer treatment before and after stent insertion had no effect on stent duration. Resonance stents are effective and safe in relieving malignant ureteral obstructions. Old age and high serum creatinine level are predictors for stent failure. Stents in patients with lower gastrointestinal cancers have longer functional duration.

  1. Reliability of mechanical and phased-array designs for serial intravascular ultrasound examinations--animal and clinical studies in stented and non-stented coronary arteries.

    Science.gov (United States)

    Tardif, J C; Bertrand, O F; Mongrain, R; Lespérance, J; Grégoire, J; Paiement, P; Bonan, R

    2000-10-01

    Both mechanical and multi-element intravascular ultrasound designs have potential advantages and limitations that may impact on their value for clinical and research purposes. Determination of the reproducibility of measurements is critical before a given system can be used in studies such as regression of atherosclerosis trials. We performed serial intravascular ultrasound imaging with catheters using mechanical and phased-array designs in stented and non-stented coronary arteries in dogs and in patients. Both systems correlated well for areas (r > or = 0.90, p or = 0.84. p mechanical designs for measurements of area (mean difference in dogs and in patients: -0.24 and 0.96 mm2, p mechanical system (r > or = 0.96 for all measurements). The differences in absolute and relative variability between the mechanical and phased-array designs, both for reanalysis of same frames and serial pullbacks, were very small. Although multi-element and mechanical intravascular ultrasound designs are not strictly interchangeable, their similar reproducibility and the small differences in measurements demonstrate that both designs are acceptable alternatives for trials of regression of atherosclerosis. Determination of the variability for serial pullbacks of both designs was also important to assess the statistical power of such trials.

  2. A comparative study of short- and medium-term outcomes comparing emergent surgery and stenting as a bridge to surgery in patients with acute malignant colonic obstruction.

    LENUS (Irish Health Repository)

    Kavanagh, Dara O

    2013-04-01

    The use of self-expanding metal stents as a bridge to surgery in the setting of malignant colorectal obstruction has been advocated as an acceptable alternative to emergency surgery. However, concerns about the safety of stenting have been raised following recent randomized studies.

  3. Placement of a Newly Designed Y-Configured Bilateral Self-Expanding Metallic Stent for Hilar Biliary Obstruction: A Pilot Study.

    Science.gov (United States)

    Jiao, Dechao; Huang, Kai; Zhu, Ming; Wu, Gang; Ren, Jianzhuang; Wang, Yanli; Han, Xinwei

    2017-01-01

    Whether unilateral or bilateral drainage should be performed for malignant hilar biliary obstruction remains a matter of debate. Although a Y-stent with a central wide-open mesh facilitates bilateral stent placement, it has its own limitations. This study aims to evaluate the feasibility and efficacy of a newly designed Y-configured bilateral self-expanding metallic stent (SEMS) for the treatment of hilar biliary obstruction. In this retrospective study, 14 consecutive patients with unresectable malignant hilar biliary obstruction (Bismuth type II or higher), who underwent placement of a newly designed Y-configured bilateral SEMS for hilar biliary obstruction from April 2013 to March 2015, were included into this study. Data on technical success, clinical success, stent patency, complications and patient survival were collected. Technical and clinical success was 100 and 92.9 %, respectively. Mean serum bilirubin level was significantly decreased 1 month after stent placement (P hilar biliary obstruction using port docking deployment.

  4. Air cholangiography in endoscopic bilateral stent-in-stent placement of metallic stents for malignant hilar biliary obstruction.

    Science.gov (United States)

    Lee, Jae Min; Lee, Sang Hyub; Jang, Dong Kee; Chung, Kwang Hyun; Park, Jin Myung; Paik, Woo Hyun; Lee, Jun Kyu; Ryu, Ji Kon; Kim, Yong-Tae

    2016-03-01

    Although endoscopic bilateral stent-in-stent (SIS) placement of self-expandable metallic stents (SEMS) is one of the major palliative treatments for unresectable malignant hilar biliary obstruction, post-endoscopic retrograde cholangiopancreatography (ERCP) cholangitis can occur frequently due to inadequate drainage, especially after contrast injection into the biliary tree. The aim of this study is to evaluate the efficacy and safety of air cholangiography-assisted stenting. This study included 47 patients with malignant hilar biliary obstruction who underwent endoscopic bilateral SEMS placement using the SIS technique. They were divided into two groups, air (n = 23) or iodine contrast (n = 24) cholangiography. We retrospectively compared comprehensive clinical and laboratory data of both groups. There were no significant differences found between the two groups with respect to technical success (87% versus 87.5%, air versus contrast group, respectively), functional success (95% versus 95.2%), 30-day mortality (8.3% versus 8.7%) and stent patency. Post-ERCP adverse events occurred in 5 (21.7%) of the patients in the air group and 8 (33.3%) of the patients in the contrast group. Among these, the rate of cholangitis was significantly lower in the air group (4.8% versus 29.2%, p = 0.048). In multivariate analysis, air cholangiography, technical success and a shorter procedure time were significantly associated with a lower incidence of post-ERCP cholangitis. Air cholangiography-assisted stenting can be a safe and effective method for endoscopic bilateral SIS placement of SEMS in patients with malignant hilar biliary obstruction.

  5. Effect of antithrombotic agents on the patency of PTFE-Covered stents in the inferior vena cava: An experimental study

    International Nuclear Information System (INIS)

    Makutani, Shiro; Kichikawa, Kimihiko; Uchida, Hideo; Maeda, Munehiro; Konishi, Noboru; Hiasa, Yoshio; Yoshikawa, Tomohiro; Kimura, Yukio

    1999-01-01

    Purpose: To evaluate the efficacy of antithrombotic agents in the prevention of stenosis of polytetrafluororethylene (PTFE)-covered stents in the venous system.Methods: Spiral Z stents covered with PTFE (PTFE-covered stents) were placed in the inferior vena cava (IVC) of 34 dogs. Nineteen dogs, used as a control group, were sacrificed at 2, 4, and 12 weeks. Fifteen dogs, previously given antithrombotic agents [cilostazol (n=5), warfarin potassium (n=5), cilostazol plus warfarin potassium (n=5)] were sacrificed at 4 weeks, and then examined angiographically and histopathologically. The effect of the antithrombotic agents was compared between groups.Results: The patency rate of the antithrombotic agent group was 93% (14/15), which was higher than the control group rate of 63% (12/19). The mean stenosis rate of the patent stent at both ends and at the midportion was lower at 4 weeks in the antithrombotic agent group than in the control group. In particular, the mean stenosis rate in the cilostazol plus warfarin potassium group was significantly lower than the control group (Tukey's test, p < 0.05). The mean neointimal thickness of the patent stent at both ends and at the midportion was thinner at 4 weeks in the antithrombotic agent group than in the control group. In particular, the thickness of the neointima in the cilostazol plus warfarin potassium group was significantly decreased when compared with the control group (Tukey's test p < 0.05). At 4 weeks, endothelialization in the antithrombotic agent group tended to be almost identical to that in the control group.Conclusion: The present study suggests that administration of an antithrombotic agent is an effective way of preventing the stenosis induced by a neointimal thickening of PTFE-covered stents in the venous system.

  6. Drug-eluting or bare-metal stents for large coronary vessel stenting? The BASKET-PROVE (PROspective Validation Examination) trial: Study protocol and design

    DEFF Research Database (Denmark)

    Pfisterer, M.; Bertel, O.; Bonetti, P.O.

    2008-01-01

    or refute this hypothesis, we set up an 11-center 4-country prospective trial of 2260 consecutive patients treated with >= 3.0-mm stents only, randomized to receive Cypher (Johnson & Johnson, Miami Lakes, FL), Vision (Abbott Vascular, Abbott Laboratories, IL), or Xience stents (Abbott Vascular). Only...

  7. A Multicenter, Prospective Study of a New Fully Covered Expandable Metal Biliary Stent for the Palliative Treatment of Malignant Bile Duct Obstruction

    Directory of Open Access Journals (Sweden)

    Bret T. Petersen

    2013-01-01

    Full Text Available Background and Study Aims. Endoscopic placement of self-expanding metal stents (SEMSs is indicated for palliation of inoperable malignant biliary obstruction. A fully covered biliary SEMS (WallFlex Biliary RX Boston Scientific, Natick, USA was assessed for palliation of extrahepatic malignant biliary obstruction. Patients and Methods. 58 patients were included in this prospective, multicenter series conducted under an FDA-approved IDE. Main outcome measurements included (1 absence of stent occlusion within six months or until death, whichever occurred first and (2 technical success, need for reintervention, bilirubin levels, stent patency, time to stent occlusion, and adverse events. Results. Technical success was achieved in 98% (57/58, with demonstrated acute removability in two patients. Adequate clinical palliation until completion of followup was achievedin 98% (54/55 of evaluable patients, with 1 reintervention due to stent obstruction after 142 days. Mean total bilirubin decreased from 8.9 mg/dL to 1.2 mg/dL at 1 month. Device-related adverse events were limited and included 2 cases of cholecystitis. One stent migrated following radiation therapy. Conclusions. The WallFlex Biliary fully covered stent yielded technically successful placement with uncomplicated acute removal where required, appropriate reduction in bilirubin levels, and low rates of stent migration and occlusion. This SEMS allows successful palliation of malignant extrahepatic biliary obstruction.

  8. Urethroplasty after Urethral Urolume Stent: an International Multicenter Experience.

    Science.gov (United States)

    Angulo, Javier C; Kulkarni, Sanjay; Pankaj, Joshi; Nikolavsky, Dmitriy; Suarez, Pedro; Belinky, Javier; Virasoro, Ramón; DeLong, Jessica; Martins, Francisco E; Lumen, Nicolaas; Giudice, Carlos; Suárez, Oscar A; Menéndez, Nicolás; Capiel, Leandro; López-Alvarado, Damian; Ramirez, Erick A; Venkatesan, Krishnan; Husainat, Maha M; Esquinas, Cristina; Arance, Ignacio; Gómez, Reynaldo; Santucci, Richard

    2018-05-08

    To evaluate the outcomes and factors affecting success of urethroplasty in patients with stricture recurrence after Urolume® urethral stent. Retrospective international multicenter study on patients treated with urethral reconstruction after Urolume® stent. Stricture and stent length, time between urethral stent insertion and urethroplasty, age, mode of stent retrieval, type of urethroplasty, complications and baseline and post-urethroplasty voiding parameters were analyzed. Successful outcome was defined as standard voiding, without need of any postoperative adjunctive procedure. Sixty-three patients were included. Stent was removed at urethroplasty in 61 patients. Reconstruction technique was excision and primary anastomosis in 14(22.2%), dorsal onlay buccal mucosa graft (BMG) 9(14.3%), ventral onlay BMG 6(9.5%), dorso-lateral onlay BMG 9(14.3%), ventral onlay plus dorsal inlay BMG 3(4.8%), augmented anastomosis 5(7.9%), pedicled flap urethroplasty 6(9.5%), 2-stage procedure 4(6.4%) and perineal urethrostomy 7(11.1%). Success rate was 81% at a mean 59.7+63.4months. Dilatation and/or internal urethrotomy was performed in 10(15.9%), redo-urethroplasty in 5(7.9%). Total IPSS, QoL, Qmax and PVR significantly improved (pUrethroplasty in patients with Urolume® urethral stents is a viable option of reconstruction with a high success rate and very acceptable complication rate. Numerous techniques are viable, however, urethral preservation, tine-by-tine stent extraction and use of BMG augmentation produced significantly better outcomes. Copyright © 2018 Elsevier Inc. All rights reserved.

  9. MR Angiography of Peripheral Arterial Stents: In Vitro Evaluation of 22 Different Stent Types

    Directory of Open Access Journals (Sweden)

    Matthias C. Burg

    2011-01-01

    Full Text Available Purpose. To evaluate stent lumen visibility of a large sample of different peripheral arterial (iliac, renal, carotid stents using magnetic resonance angiography in vitro. Materials and Methods. 21 different stents and one stentgraft (10 nitinol, 7 316L, 2 tantalum, 1 cobalt superalloy, 1 PET + cobalt superalloy, and 1 platinum alloy were examined in a vessel phantom (vessel diameters ranging from 5 to 13 mm filled with a solution of Gd-DTPA. Stents were imaged at 1.5 Tesla using a T1-weighted 3D spoiled gradient-echo sequence. Image analysis was performed measuring three categories: Signal intensity in the stent lumen, lumen visibility of the stented lumen, and homogeneity of the stented lumen. The results were classified using a 3-point scale (good, intermediate, and poor results. Results. 7 stents showed good MR lumen visibility (4x nitinol, 2x tantalum, and 1x cobalt superalloy. 9 stents showed intermediate results (5x nitinol, 2x 316L, 1x PET + cobalt superalloy, and 1x platinum alloy and 6 stents showed poor results (1x nitinol, and 5x 316L. Conclusion. Stent lumen visibility varies depending on the stent material and type. Some products show good lumen visibility which may allow the detection of stenoses inside the lumen, while other products cause artifacts which prevent reliable evaluation of the stent lumen with this technique.

  10. The degradation and transport mechanism of a Mg-Nd-Zn-Zr stent in rabbit common carotid artery: A 20-month study.

    Science.gov (United States)

    Zhang, Jian; Li, Haiyan; Wang, Wu; Huang, Hua; Pei, Jia; Qu, Haiyun; Yuan, Guangyin; Li, Yongdong

    2018-03-15

    Mg-based stent is a promising candidate of the next generation fully degradable vascular stents. The latest progress includes the CE approval of the Magmaris ® WE43 based drug eluting stent. However, so far, the long term (more than 1 year implantation) in vivo degradation and the physiological effects caused by the degradation products were still unclear. In this study, a 20 month observation was carried out after the bare Mg-Nd-Zn-Zr (abbr. JDBM) stent prototype was implanted into the common carotid artery of New Zealand white rabbit in order to evaluate its safety, efficacy and especially degradation behavior. The degradation of the main second phase Mg 12 Nd was also studied. Results showed that the bare JDBM stent had good safety and efficacy with a complete re-endothelialization within 28 days. The JDBM stent struts were mostly replaced in situ by degradation products in 4 month. The important finding was that the volume and Ca concentration of the degradation products decreased in the long term, eliminating the clinicians' concern of possible vessel calcification. In addition, the alloying elements Mg and Zn in the stent could be safely metabolized as continuous enrichment in any of the main organs were not detected although Nd and Zr showed an abrupt increase in spleen and liver after 1 month implantation. Collectively, the long term in vivo results showed the rapid re-endothelialization of JDBM stent and the long term safety of the degradation products, indicating its great potential as the backbone of the fully degradable vascular stent. Mg-based stent is a promising candidate of the next generation fully degradable stents, especially after the recent market launch of one of its kind (Magmaris). However the fundamental question about the long term degradation and metabolic mechanism of Mg-based stent and its degradation products remain unanswered. We implanted our patented Mg-Nd-Zn-Zr bare stent into the common carotid artery of rabbits and

  11. The Role of Minimally Invasive Vertebral Body Stent on Reduction of the Deflation Effect After Kyphoplasty: A Biomechanical Study.

    Science.gov (United States)

    Wang, Dalin; Zheng, Shengnai; Liu, An; Xu, Jie; Du, Xiaotao; Wang, Yijin; Wang, Liming

    2018-03-15

    Biomechanical investigation using cadaver spines. The aim of the present study was to assess the magnitude of the deflation effect after balloon kyphoplasty (BKP) or use of minimally invasive vertebral body stent (MIVBS) in in vitro biomechanical condition. BKP is a well-established minimally invasive treatment option for osteoporotic vertebral compression fractures. However, this technique can lead to a secondary height loss-known as the "deflation effect"-causing intrasegmental kyphosis and an overall alignment failure. The study was conducted on 24 human cadaveric vertebral bodies (T12-L5). After creating a compression fracture model, the fractured vertebral bodies were reduced by BKP (n = 12) or by MIVBS (n = 12) and then augmented with polymethyl methacrylate bone cement. Each step of the procedure was performed under fluoroscopic guidance and the results were analyzed quantitatively. Finally, the strength and stiffness of augmented vertebral bodies were measured by biomechanical tests. Complete initial reduction of the fractured vertebral body height was achieved by both systems. Secondary loss of reduction after balloon deflation was significantly greater in the BKP group (2.36 ± 0.63 mm vs. 0.34 ± 0.43 mm in the MIVBS group; P deflation effect after BKP can be significantly decreased with the use of the MIVBS technique. N/A.

  12. Endovascular treatment of experimentally induced aneurysms in rabbits using stents: a feasibility study

    International Nuclear Information System (INIS)

    Hans, F.J.; Thiex, R.; Gilsbach, J.M.; Krings, T.; Moeller-Hartmann, W.; Dreeskamp, H.; Stein, K.P.; Meetz, A.; Thron, A.; Pfeffer, J.; Scherer, K.; Brunn, A.

    2003-01-01

    Although Guglielmi detachable coil (GDC) systems have been generally accepted for treatment of intracranial aneurysms, primary stenting of aneurysms using porous stents or implantation of coils after stent placement remains experimental. Testing of these new methods requires an animal model which imitates human aneurysms in size, configuration and neck morphology. We assessed in detail the technical requirements of and steps for transfemoral stent treatment of experimentally induced aneurysms at the top of the brachiocephalic trunk in rabbits. We created aneurysms in ten rabbits by distal ligation and intraluminal digestion of the right common carotid artery with elastase. We treated five animals with porous stents alone, and five with stents plus coiling via the meshes of the stent, which permitted dense packing of coils. No complications related to the procedures occurred. In all animals, even in those treated solely with porous stents, total occlusion of the aneurysm was achieved. Our animal model can be suitable for testing the biocompatibility and occlusion rate of new methods and devices for the treatment of experimental aneurysms. (orig.)

  13. Evaluation of the Anti-migration Effect of Barbed Prostatic Stents: In Vitro Study in Urethra-mimicking Bovine Pericardium Phantoms

    International Nuclear Information System (INIS)

    Na, Han Kyu; Song, Ho-Young; Kim, Jin Hyoung; Nam, Deok Ho; Park, Jung-Hoon; Jeong, In Gab; Kim, Choung-Soo

    2013-01-01

    This study was designed to compare the migration rates of covered stents with eight, four, and zero barbs in urethra-mimicking bovine pericardium models. Three types of polytetrafluoroethylene-covered retrievable self-expandable prostatic stents, with eight, four, and zero barbs, were tested in bovine pericardium models, consisting of normal saline-filled acrylic containers with tubes at both ends and a replica of the human urethra. The barbs were 2 mm in length and projected 60° toward the urinary bladder. The anti-migration force (AMF) and resistance force against stent removal (RFSR) were measured by an automatic push–pull gauge system at a fixed rate (2 mm/s). Significant differences in AMF among the three stent types were detected (P < 0.001). Median AMF was far greater for eight-barbed than for four-barbed stents (11.96 vs. 7.55 N, P = 0.003). For stent removal, the difference between 4- and 8-barbed stents were not significant in median static (5.54 vs. 6.08 N, P = 0.15) or sliding (prostatic urethra, 5.32 vs. 5.59 N, P = 0.65; membranous urethra, 7.78 vs. 8.57 N, P = 0.364) RFSR. No perforations or scratched traces were observed during removal of these stents. The inclusion of eight barbs projecting 60° toward the urinary bladder were not only effective against stent migration in this model but suggests that these stents may be suitable for the treatment of prostatic urethral strictures without severely irritating the tissue. However, whether these results translate into living urethral tissue is unclear, necessitating further studies.

  14. Evaluation of the anti-migration effect of barbed prostatic stents: in vitro study in urethra-mimicking bovine pericardium phantoms.

    Science.gov (United States)

    Na, Han Kyu; Song, Ho-Young; Kim, Jin Hyoung; Nam, Deok Ho; Park, Jung-Hoon; Jeong, In Gab; Kim, Choung-Soo

    2013-02-01

    This study was designed to compare the migration rates of covered stents with eight, four, and zero barbs in urethra-mimicking bovine pericardium models. Three types of polytetrafluoroethylene-covered retrievable self-expandable prostatic stents, with eight, four, and zero barbs, were tested in bovine pericardium models, consisting of normal saline-filled acrylic containers with tubes at both ends and a replica of the human urethra. The barbs were 2 mm in length and projected 60° toward the urinary bladder. The anti-migration force (AMF) and resistance force against stent removal (RFSR) were measured by an automatic push-pull gauge system at a fixed rate (2 mm/s). Significant differences in AMF among the three stent types were detected (P barbed than for four-barbed stents (11.96 vs. 7.55 N, P = 0.003). For stent removal, the difference between 4- and 8-barbed stents were not significant in median static (5.54 vs. 6.08 N, P = 0.15) or sliding (prostatic urethra, 5.32 vs. 5.59 N, P = 0.65; membranous urethra, 7.78 vs. 8.57 N, P = 0.364) RFSR. No perforations or scratched traces were observed during removal of these stents. The inclusion of eight barbs projecting 60° toward the urinary bladder were not only effective against stent migration in this model but suggests that these stents may be suitable for the treatment of prostatic urethral strictures without severely irritating the tissue. However, whether these results translate into living urethral tissue is unclear, necessitating further studies.

  15. Evaluation of the Anti-migration Effect of Barbed Prostatic Stents: In Vitro Study in Urethra-mimicking Bovine Pericardium Phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Na, Han Kyu, E-mail: hankyu1324@empas.com; Song, Ho-Young, E-mail: hysong@amc.seoul.kr; Kim, Jin Hyoung, E-mail: m1fenew@hanmail.net [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Asan Medical Center (Korea, Republic of); Nam, Deok Ho, E-mail: namjindan@paran.com [Kyung Hee University Hospital at Gangdong, School of Medicine, Kyung Hee University, Department of Radiology (Korea, Republic of); Park, Jung-Hoon, E-mail: jhparkz@amc.seoul.kr [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Asan Medical Center (Korea, Republic of); Jeong, In Gab, E-mail: uroman2000@yahoo.co.kr; Kim, Choung-Soo, E-mail: cskim@amc.seoul.kr [University of Ulsan College of Medicine, Department of Urology, Asan Medical Center (Korea, Republic of)

    2013-02-15

    This study was designed to compare the migration rates of covered stents with eight, four, and zero barbs in urethra-mimicking bovine pericardium models. Three types of polytetrafluoroethylene-covered retrievable self-expandable prostatic stents, with eight, four, and zero barbs, were tested in bovine pericardium models, consisting of normal saline-filled acrylic containers with tubes at both ends and a replica of the human urethra. The barbs were 2 mm in length and projected 60 Degree-Sign toward the urinary bladder. The anti-migration force (AMF) and resistance force against stent removal (RFSR) were measured by an automatic push-pull gauge system at a fixed rate (2 mm/s). Significant differences in AMF among the three stent types were detected (P < 0.001). Median AMF was far greater for eight-barbed than for four-barbed stents (11.96 vs. 7.55 N, P = 0.003). For stent removal, the difference between 4- and 8-barbed stents were not significant in median static (5.54 vs. 6.08 N, P = 0.15) or sliding (prostatic urethra, 5.32 vs. 5.59 N, P = 0.65; membranous urethra, 7.78 vs. 8.57 N, P = 0.364) RFSR. No perforations or scratched traces were observed during removal of these stents. The inclusion of eight barbs projecting 60 Degree-Sign toward the urinary bladder were not only effective against stent migration in this model but suggests that these stents may be suitable for the treatment of prostatic urethral strictures without severely irritating the tissue. However, whether these results translate into living urethral tissue is unclear, necessitating further studies.

  16. Endoscopic stent suture fixation for prevention of esophageal stent migration during prolonged dilatation for achalasia treatment.

    Science.gov (United States)

    Rieder, E; Asari, R; Paireder, M; Lenglinger, J; Schoppmann, S F

    2017-04-01

    The aim of this study is to compare endoscopic stent suture fixation with endoscopic clip attachment or the use of partially covered stents (PCS) regarding their capability to prevent stent migration during prolonged dilatation in achalasia. Large-diameter self-expanding metal stents (30 mm × 80 mm) were placed across the gastroesophageal junction in 11 patients with achalasia. Stent removal was scheduled after 4 to 7 days. To prevent stent dislocation, endoscopic clip attachment, endoscopic stent suture fixation, or PCS were used. The Eckardt score was evaluated before and 6 months after prolonged dilatation. After endoscopic stent suture fixation, no (0/4) sutured stent migrated. When endoscopic clips were used, 80% (4/5) clipped stents migrated (p = 0.02). Of two PCS (n = 2), one migrated and one became embedded leading to difficult stent removal. Technical adverse events were not seen in endoscopic stent suture fixation but were significantly correlated with the use of clips or PCS (r = 0.828, p = 0.02). Overall, 72% of patients were in remission regarding their achalasia symptoms 6 months after prolonged dilatation. Endoscopic suture fixation of esophageal stents but not clip attachment appears to be the best method of preventing early migration of esophageal stents placed at difficult locations such as at the naive gastroesophageal junction. © The Authors 2017. Published by Oxford University Press on behalf of International Society for Diseases of the Esophagus. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. [The Predictive Factors of Stent Failure in the Treatment of Malignant Extrinsc Ureteral Obstruction Using Internal Ureteral Stents].

    Science.gov (United States)

    Matsuura, Hiroshi; Arase, Shigeki; Hori, Yasuhide; Tochigi, Hiromi

    2017-12-01

    In this study, we retrospectively reviewed the experiences at our single institute in the treatment of malignant extrinsic ureteral obstruction (MUO) using ureteral stents to investigate the clinical outcomes and the predictive factors of stent failure. In 52 ureters of 38 patients who had radiologically significant hydronephrosis due to MUO, internal ureteral stents (The BARD(R) INLAY(TM) ureteral stent set) were inserted. The median follow-up interval after the initial stent insertion was 124.5 days (4-1,120). Stent failure occurred in 8 ureters (15.4%) of the 7 patients. The median interval from the first stent insertion to stent failure was 88 days (1-468). A Cox regression multivariate analysis showed that the significant predictors of stent failure were bladder invasion. Based on the possibility of stent failure, the adaptation of the internal ureteral stent placement should be considered especially in a patient with MUO combined with bladder invasion.

  18. The numerical simulation study of hemodynamics of the new dense-mesh stent

    Science.gov (United States)

    Ma, Jiali; Yuan, Zhishan; Yu, Xuebao; Feng, Zhaowei; Miao, Weidong; Xu, Xueli; Li, Juntao

    2017-09-01

    The treatment of aortic aneurysm in new dense mesh stent is based on the principle of hemodynamic changes. But the mechanism is not yet very clear. This paper analyzed and calculated the hemodynamic situation before and after the new dense mesh stent implanting by the method of numerical simulation. The results show the dense mesh stent changed and impacted the blood flow in the aortic aneurysm. The changes include significant decrement of blood velocity, pressure and shear forces, while ensuring blood can supply branches, which means the new dense mesh stent's hemodynamic mechanism in the treatment of aortic aneurysm is clearer. It has very important significance in developing new dense mesh stent in order to cure aortic aneurysm.

  19. A comparative evaluation of early stent occlusion among biliary conventional versus wing stents.

    Science.gov (United States)

    Khashab, Mouen A; Hutfless, Susan; Kim, Katherine; Lennon, Anne Marie; Canto, Marcia I; Jagannath, Sanjay B; Okolo, Patrick I; Shin, Eun Ji; Singh, Vikesh K

    2012-06-01

    Conventional plastic stents with a lumen typically have limited patency. The lumenless wing stent was engineered to overcome this problem. The objective of this study was to compare the incidence of early stent occlusion (symptomatic occlusion/cholangitis necessitating re-insertion within 90 days) for wing stents and conventional plastic stents. Patients with biliary pathology treated with plastic biliary stenting during the period 2003-2009 comprised the study cohort. Patients who had at least one biliary wing stent placed comprised the wing stent group, whereas patients who underwent only conventional stent plastic placement comprised the conventional stent group. Patients were stratified by indication: benign biliary strictures (group 1), malignant biliary strictures (group 2), or benign biliary non-stricture pathology (group 3). The association of stent type with the occurrence of primary outcome by indication was analyzed by use of multivariable logistic regression. Three-hundred and forty-six patients underwent 612 ERCP procedures with placement of plastic biliary stent(s). On multivariate analysis, early stent occlusion did not differ between the wing and conventional groups in groups 1, 2, and 3. Among patients who achieved primary outcome in group 2, significantly fewer patients in the wing group had cholangitis (6.7% vs. 39.1%, P = 0.03). Among patients who achieved primary outcome in group 3, significantly fewer patients in the wing group had cholangitis (10% vs. 50%, P = 0.03). Early stent occlusion was similar for wing stents and conventional plastic stents. Wing stents, however, were associated with a lower incidence of cholangitis in patients with malignant biliary obstruction and benign non-stricturing biliary pathology.

  20. Optimization of cardiovascular stent against restenosis: factorial design-based statistical analysis of polymer coating conditions.

    Directory of Open Access Journals (Sweden)

    Gayathri Acharya

    Full Text Available The objective of this study was to optimize the physicodynamic conditions of polymeric system as a coating substrate for drug eluting stents against restenosis. As Nitric Oxide (NO has multifunctional activities, such as regulating blood flow and pressure, and influencing thrombus formation, a continuous and spatiotemporal delivery of NO loaded in the polymer based nanoparticles could be a viable option to reduce and prevent restenosis. To identify the most suitable carrier for S-Nitrosoglutathione (GSNO, a NO prodrug, stents were coated with various polymers, such as poly (lactic-co-glycolic acid (PLGA, polyethylene glycol (PEG and polycaprolactone (PCL, using solvent evaporation technique. Full factorial design was used to evaluate the effects of the formulation variables in polymer-based stent coatings on the GSNO release rate and weight loss rate. The least square regression model was used for data analysis in the optimization process. The polymer-coated stents were further assessed with Differential scanning calorimetry (DSC, Fourier transform infrared spectroscopy analysis (FTIR, Scanning electron microscopy (SEM images and platelet adhesion studies. Stents coated with PCL matrix displayed more sustained and controlled drug release profiles than those coated with PLGA and PEG. Stents coated with PCL matrix showed the least platelet adhesion rate. Subsequently, stents coated with PCL matrix were subjected to the further optimization processes for improvement of surface morphology and enhancement of the drug release duration. The results of this study demonstrated that PCL matrix containing GSNO is a promising system for stent surface coating against restenosis.

  1. Evaluation of Silicone as an Endovascular Stent Membrane: In Vivo Canine Studies

    International Nuclear Information System (INIS)

    Fontaine, Arthur B.; Borsa, John J.; Hoffer, Eric; Bloch, Robert; So, Corali

    2001-01-01

    Purpose: Comparative evaluation of the biological effects of a silicone-covered stent versus a bare-metal stent, in an animal model.Methods: Twelve stent implants were placed in the iliac arteries of six adult dogs. Each animal received one 8-mm x 20-mm silicone-covered stent (Permalume; Boston Scientific Vascular, Watertown, MA, USA), in the right iliac artery and one Wallstent (Boston Scientific Vascular) of the same diameter and length in the left iliac artery, during systemic anticoagulation. Angiography was performed before and after implantations. Animals were then allowed to recover and no platelet suppression was given during a 6-week interval, after which the animals were euthanized. The stented arteries were isolated and pressure-fixed in situ with 10% buffered formalin at a pressure of approximately 100 mmHg for a period of 1 hr. Two of 12 stented specimens were opened lengthwise and the luminal surfaces were photographed. Ten of 12 stented arterial segments were encased in methacrylate, then stained with hematoxylin and eosin. Neointimal thickness was quantified on histologic cross-section, for both bare and covered stents. The mean neointimal thicknesses were compared for significant difference using a student t-test.Results: All implants were widely patent at 6-week follow-up angiography. Histologic analysis showed bare metal stents covered by a thin uniform lining of neointima composed of smooth muscle cells in a hyaline matrix (mean thickness of 189 ± 47 μm). Silicone covered stents were devoid of neointima. There was no chronic thrombus or mature endothelium noted anywhere upon the internal silicone surfaces of any of the specimens. There was no foreign body reaction to the silicone cover.Conclusion: Short-term implantation of a silicone-lined Wallstent in canine iliac arteries is well tolerated. Silicone appears to be inert at 6 weeks in this experimental application

  2. A US Multicenter Study of Safety and Efficacy of Fully Covered Self-Expandable Metallic Stents in Benign Extrahepatic Biliary Strictures.

    Science.gov (United States)

    Saxena, Payal; Diehl, David L; Kumbhari, Vivek; Shieh, Frederick; Buscaglia, Jonathan M; Sze, Wilson; Kapoor, Sumit; Komanduri, Srinadh; Nasr, John; Shin, Eun Ji; Singh, Vikesh; Lennon, Anne Marie; Kalloo, Anthony N; Khashab, Mouen A

    2015-11-01

    Endoscopic therapy is considered first line for management of benign biliary strictures (BBSs). Placement of plastic stents has been effective but limited by their short-term patency and need for repeated procedures. Fully covered self-expandable metallic stents (FCSEMSs) offer longer-lasting biliary drainage without the need for frequent exchanges. The aim of this study was to assess the efficacy and safety of FCSEMS in patients with BBS. A retrospective review of all patients who underwent ERCP and FCSEMS placement at five tertiary referral US hospitals was performed. Stricture resolution and adverse events related to ERCP and/or stenting were recorded. A total of 123 patients underwent FCSEMS placement for BBS and 112 underwent a subsequent follow-up ERCP. The mean age was 62 years (±15.6), and 57% were males. Stricture resolution occurred in 81% of patients after a mean of 1.2 stenting procedures (mean stent dwell time 24.4 ± 2.3 weeks), with a mean follow-up of 18.5 months. Stricture recurrence occurred in 5 patients, and 3 patients required surgery for treatment of refractory strictures. Stent migration (9.7%) was the most common complication, followed by stent occlusion (4.9%), cholangitis (4.1%), and pancreatitis (3.3%). There was one case of stent fracture during removal, and one stent could not be removed. There was one death due to cholangitis. Majority of BBS can be successfully managed with 1-2 consecutive FCSEMS with stent dwell time of 6 months.

  3. 3D Stereoscopic Visualization of Fenestrated Stent Grafts

    International Nuclear Information System (INIS)

    Sun Zhonghua; Squelch, Andrew; Bartlett, Andrew; Cunningham, Kylie; Lawrence-Brown, Michael

    2009-01-01

    The purpose of this study was to present a technique of stereoscopic visualization in the evaluation of patients with abdominal aortic aneurysm treated with fenestrated stent grafts compared with conventional 2D visualizations. Two patients with abdominal aortic aneurysm undergoing fenestrated stent grafting were selected for inclusion in the study. Conventional 2D views including axial, multiplanar reformation, maximum-intensity projection, and volume rendering and 3D stereoscopic visualizations were assessed by two experienced reviewers independently with regard to the treatment outcomes of fenestrated repair. Interobserver agreement was assessed with Kendall's W statistic. Multiplanar reformation and maximum-intensity projection visualizations were scored the highest in the evaluation of parameters related to the fenestrated stent grafting, while 3D stereoscopic visualization was scored as valuable in the evaluation of appearance (any distortions) of the fenestrated stent. Volume rendering was found to play a limited role in the follow-up of fenestrated stent grafting. 3D stereoscopic visualization adds additional information that assists endovascular specialists to identify any distortions of the fenestrated stents when compared with 2D visualizations.

  4. Functional Nanoarchitectures For Enhanced Drug Eluting Stents

    Science.gov (United States)

    Saleh, Yomna E.; Gepreel, Mohamed A.; Allam, Nageh K.

    2017-01-01

    Different strategies have been investigated to allow for optimum duration and conditions for endothelium healing through the enhancement of coronary stents. In this study, a nanoarchitectured system is proposed as a surface modification for drug eluting stents. Highly oriented nanotubes were vertically grown on the surface of a new Ni-free biocompatible Ti-based alloy, as a potential material for self-expandable stents. The fabricated nanotubes were self-grown from the potential stent substrate, which are also proposed to enhance endothelial proliferation while acting as drug reservoir to hinder Vascular Smooth Muscle Cells (VSMC) proliferation. Two morphologies were synthesized to investigate the effect of structure homogeneity on the intended application. The material was characterized by field-emission scanning electron microscope (FESEM), X-ray diffraction (XRD), Raman spectroscopy, energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). Nanoindentation technique was used to study the mechanical properties of the fabricated material. Cytotoxicity and proliferation studies were performed and compared for the two fabricated nanoarchitectures, versus smooth untextured samples, using in-vitro cultured endothelial cells. Finally, the drug loading capacity was experimentally studied and further supported by computational modeling of the release profile.

  5. Usefulness of CT angiography after metallic stent implantation of the internal carotid artery

    International Nuclear Information System (INIS)

    Yoon, Man Won; Kim, Hyeon Chul; Kim, Jae Kyu; Seo, Jeong Jin; Jeong, Gwang Woo; Kang, Heoung Keun

    1999-01-01

    To evaluate the usefulness of CT angiography in patients with implantation of metallic stent for stenosed internal carotid artery. Seven patients with atherosclerotic stenosis of the internal carotid artery underwent metallic stent implantation. All were male and their ages ranged from 36 to 69 years. A total of seven stents were placed in the internal carotid artery in five patients and in the carotid bifurcation in two. Spiral CT scans were obtained and CT angiographic images were reconstructed using MPR or curved MPR techniques at a workstation. The interval between CT and conventional angiography did not exceed six days except in one patient, in whom it was 61days. CT and conventional angiography were compared for stent position with respect to the carotid bifurcation, stent deformation, intraluminal filling defect, and luminal caliber and outflow. Luminal patency of the implanted stent was measured according to NASCET(North American Symptomatic Carotid Endarterectomy Trial) criteria, and statistically processed (p>.05). The presence or absence of intrastent thrombus and vascular wall calcification was determined using axial source images. In all patients, CT angiographic findings matched those obtained by conventional angiography. Complications such as migration or deformation of an implanted stent, intraluminal filling defect, change of luminal caliber or outflow of implanted stent were not observed in any patient. In two studies in which Wilcoxon signed rank test was used, degree of stent expansion correlated closely(p=0.237). Axial source images showed that in no patient was an intrastent thrombus present, though in five, vascular wall calcification of internal carotid arteries outside the stent was noted. CT angiography is useful for the assessment of positional change, occlusion, and luminal patency of a stent-implanted internal carotid artery

  6. In-stent neoatherosclerosis and tissue characteristics of restenotic lesions following implantation of second generation drug-eluting stents in unrestricted coronary lesions: Optical frequency domain imaging study.

    Science.gov (United States)

    Sabbah, Mahmoud; Kadota, Kazushige; El-Eraky, Azza; Kamal, Hanan M; Abdellah, Ahmed-Tageldien; El Hawary, Ahmed

    2017-06-01

    Differences in stent platform, polymer coatings, and antirestenotic drugs among the current in use second-generation drug-eluting stents (G2-DESs) may induce significant variations in neointimal response and vascular healing, which may impact the prevalence of neoatherosclerosis (NA) and morphological appearance of the restenotic tissue. Utilizing Optical frequency domain imaging, two independent reviewers, retrospectively compared the prevalence of neoatherosclerosis (NA), and the morphological differences, and tissue characteristics of 50 G2-DESs in-stent restenosis (ISR) lesions (35 everolimus-eluting stent [22 cobalt-chromium (CoCr), 13 platinum-chromium (PtCr)], and 15 biolimus-eluting stent [BES]) implanted liberally in unrestricted coronary lesions. More than half of the stents were implanted in type C lesions, while 40% of the stents were implanted primarily in lesions with recanalized chronic total occlusion. NA, defined as a neointima formation with the presence of lipids or calcification, was observed in fewer than half (24/50) of all ISR lesions with no significant in-between group differences (41%, 69%, and 40% in CoCr, PtCr, and BES respectively, P = 0.22), nor were there any significant differences in the morphological appearance or tissue characteristics between all G2-DESs subtypes. Acknowledging some limitations, our results may suggest that the prevalence of NA and the morphological appearance of restenotic lesions might not differ when G2-DESs are implanted in unrestricted, rather complex, coronary lesions. © 2017, Wiley Periodicals, Inc.

  7. Experimental comparison study of the tissue characteristics in transjugular intrahepatic portosystemic shunt and vascular stent

    International Nuclear Information System (INIS)

    Lu Qin; An Yanli; Deng Gang; Fang Wen; Zhu Guangyu; Niu Huanzhang; Yu Hui; Li Guozhao; Teng Gaojun; Wang Zhen; Wei Xiaoying

    2009-01-01

    Objective: To investigate the tissue characteristics within vascular stent and transjugular intrahepatic portosystemic shunt(TIPS) on swine and to provide more information for the understanding and prevention of vascular stent and TIPS restenosis. Methods: Animal models for TIPS were built in 6 swine and vascular stents were implanted in iliac veins simultaneously. 14-28 days after the operation, the 6 swine were killed to remove the TIPS and vascular stent and the pathological examinations were performed on the tissues within the shunt and stent. The similarities and differences of the tissues within the shunt and stent were analyzed with Krttskal Wallis test. Results: Restenosis of TIPS occurred in 4 models and complete occlusion were seen in 2, while all vascular stents were patent and coated with a thin layer of intimal tissue. Electron microscopic results showed that the tissues in restenotic TIPS were loose and with more extra matrix and fibers, and less smooth muscle, fibroblastic and myofibroblastic cells with different and irregular shape and rich secretory granules. The tissues in patent TIPS contained more extra fibers, smooth muscle and fibroblastic cells with normal organelle. The intimal tissues in vascular stent contained more fibers and fibroblasts cells, less smooth muscle cells. On immunohistochemical staining, the tissues in restenotic and patent TIPS as well as the intimal tissues in vascular stent had strong positive expression for anti-SMC- actin-α, the expression were gradually weakened for PCNA, the intimal tissues in vascular stent had a strong positive expression for vimentin, while the expression of the tissues in restenotic and patent TIPS were weakened gradually. For myoglobulin, the tissues in restenotic TIPS had weakly positive expression, the expression in patent TIPS and vascular stent were almost negative. Western blot results for TGF-β showed that the absorbance ratios of the intima tissues in vascular stent, normal vascular

  8. Anatomic study of juxta renal aneurysms: impact on fenestrated stent-grafts.

    Science.gov (United States)

    Azzaoui, Richard; Sobocinski, Jonathan; Maurel, Blandine; D'Elia, Piervito; Perrot, Céline; Bianchini, Aurélia; Guillou, Matthieu; Haulon, Stéphan

    2011-04-01

    Fenestrated stent-grafts allow for treatment of patients with juxtarenal aneurysms (JRA) when they present with contraindications for conventional treatment. The fenestrated module is a custom-made module, specially designed to fit a specific patient, using computed tomographic scan measurements, which entails manufacturing delay and high cost. The aim of our study was to evaluate the possibility to reproduce the interrenal aorta anatomy to design a standard fenestrated module that would fit the maximum number of patients with JRA. On a three-dimensional working station, we analyzed 289 preoperative computed tomographic scan results of patients with JRA and who were treated with fenestrated stent-grafts comprising two fenestrations for the renal arteries and a scallop for the superior mesenteric artery (SMA). On curvilinear reconstructions, we successively measured the interrenal aorta diameter, its orientation, as well as the height of each renal ostium, taking the ostium center of the SMA as a reference mark. Later, a statistical analysis of these measures distribution was performed so as to design a fenestrated module that would fit the maximum number of patients. The center of the left renal artery presented with a median orientation of 82.5° (range, 37.5-150) and a median distance of 9 mm (range, 0-30), in relation to the SMA ostium. The ostium center of the right renal artery presented with a median orientation of 285° (range, 240-337.5) and a median distance of 8 mm (range, 3-30), in relation to the SMA ostium. By positioning the current renal fenestrations (6-mm wide), on the basis of the calculated median positions, in our series, only 20% of the patients could be treated with a standard fenestrated module. Should the diameter of these fenestrations be increased by 10 mm, it would then be possible to treat 50% of our patients. The anatomy of the interrenal aorta and its branches is quite reproducible to design standard fenestrated stent-grafts that could

  9. Direct implantation of rapamycin-eluting stents with bioresorbable drug carrier technology utilising the Svelte coronary stent-on-a-wire: the DIRECT II study.

    Science.gov (United States)

    Verheye, Stefan; Khattab, Ahmed A; Carrie, Didier; Stella, Pieter; Slagboom, Ton; Bartunek, Jozef; Onuma, Yoshinobu; Serruys, Patrick W

    2016-08-05

    Our aim was to demonstrate the safety and efficacy of the Svelte sirolimus-eluting coronary stent-on-a-wire Integrated Delivery System (IDS) with bioresorbable drug coating compared to the Resolute Integrity zotarolimus-eluting stent with durable polymer in patients with de novo coronary artery lesions. Direct stenting, particularly in conjunction with transradial intervention (TRI), has been associated with reduced bleeding complications, procedure time, radiation exposure and contrast administration compared to conventional stenting with wiring and predilatation. The low-profile Svelte IDS is designed to facilitate TRI and direct stenting, reducing the number of procedural steps, time and cost associated with coronary stenting. DIRECT II was a prospective, multicentre trial which enrolled 159 patients to establish non-inferiority of the Svelte IDS versus Resolute Integrity using a 2:1 randomisation. The primary endpoint was angiographic in-stent late lumen loss (LLL) at six months. Target vessel failure (TVF), as well as secondary clinical endpoints, will be assessed annually up to five years. At six months, in-stent LLL was 0.09±0.31 mm in the Svelte IDS group compared to 0.13±0.27 mm in the Resolute Integrity group (p<0.001 for non-inferiority). TVF at one year was similar across the Svelte IDS and Resolute Integrity groups (6.5% vs. 9.8%, respectively). DIRECT II demonstrated the non-inferiority of the Svelte IDS to Resolute Integrity with respect to in-stent LLL at six months. Clinical outcomes at one year were comparable between the two groups.

  10. The Role of Tracheal Stenting As an Alternative Treatment in Cicatricial and Non-Operable Tracheal Stenosis

    Directory of Open Access Journals (Sweden)

    Reza Bagheri

    2013-05-01

    Full Text Available Introduction: Tracheal stenosis is normally caused by trauma, infection, benign and malignant tumors, prolonged intubation or tracheostomy. The best treatment for tracheal stenosis is resection and anastomosis of trachea. Yet the major surgical complication of tracheal surgery is postoperative stenosis. The goal of this paper is to study the result of tracheal stenting as a replacement therapy for patients suffering from tracheal stenosis who are not good candidates for surgery. Materials and Methods: This study presents the results of stenting in patients with: Inoperable tumoral stenosis,Non-tumoral stenosis being complicated due to prior surgeries,Inability to undergo a major surgery.The study was performed between September 2002 and July 2011 and poly flex stents were used by means of rigid bronchoscopy. Results: A total of 25 patients received stents during this study. Among them 15 patients suffered from benign and 10 suffered from malignant tracheal stenosis. The patients were followed up for at most 12 months after the stenting operation. The mean age of the patients was 35 years. The most common cause of stenosis was prolonged intubation (75%. The most common indication for stenting was the history of multiple tracheal operations. The most common complication of stenting and cause of stent removal was formation of granulation tissue. 30% of patients with benign tracheal stenosis were cured and about 10% improved until they could stand a major operation. Ten patients in benign group and 2 patients in malignant group (20% needed T-Tube insertion after stent removal but other patientcure by stenting. Conclusions: In benign cases stenting is associated with recurrence of symptoms which requires other therapeutic techniqus, so the stenting may not be named as a final solution in benign cases. However, this technique is the only method with approved efficacy for malignant cases with indication.

  11. Subclinical ischemic events in patients undergoing carotid artery stent placement: comparison of proximal and distal protection techniques.

    Science.gov (United States)

    Aytac, Emrah; Gürkaş, Erdem; Akpinar, Cetin Kursad; Saleem, Muhammad A; Qureshi, Adnan I

    2017-10-01

    To determine the relative effectiveness of proximal and distal protection in prevention of cerebral ischemic events during carotid artery stent (CAS) placement using diffusion-weighted MRI (DW-MRI). We analyzed data from patients who had undergone DW-MRI before and within 24 hours of CAS for symptomatic internal carotid artery (ICA) stenosis (with last ischemic events within 3 months). The study was performed prospectively; patients were not randomized, and were treated either with a proximal balloon occlusion system (Mo.Ma; Invatec, Roncadelle, Italy) or filter-type distal protection device (Spider device; ev3, Plymouth, Minnesota, USA). Of the 45 patients (mean age±SD: 66.9±9.8 years; 73.3% were men) who underwent CAS, 19 had proximal protection and 26 distal protection. New ischemic lesions were detected in 26/45 patients on DW-MRI scans obtained within 24 hours after CAS. The proportion of patients with new lesions on DW-MRI at 24 hours was not different between the two groups (47.4% vs 65.4% for proximal and distal protection, respectively). The mean number of new ischemic lesions on post-CAS DW-MRI was non-significantly higher in patients who underwent CAS with distal protection (2.80±3.54 for proximal protection vs 4.96±5.11 for distal protection; p=0.12). The proportion of patients with new lesions >1 cm did not differ between the two groups (5.3% for proximal protection vs 11.5% for distal protection; p=0.62). There was no difference in the rates of ischemic stroke between patients who underwent CAS treatment using proximal and distal protection (5.3% vs 7.7%; p=1.000). We found a relatively high rate of new ischemic lesions in patients undergoing CAS with cerebral protection. There was no difference in the proportion of patients with new lesions between patients treated using distal protection and those treated using proximal protection. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a

  12. Endoscopic removal of malfunctioning biliary self-expandable metallic stents.

    Science.gov (United States)

    Familiari, Pietro; Bulajic, Milutin; Mutignani, Massimiliano; Lee, Linda S; Spera, Gianluca; Spada, Cristiano; Tringali, Andrea; Costamagna, Guido

    2005-12-01

    Endoscopic removal of malfunctioning self-expandable metallic biliary stents (SEMS) is difficult and not well described. The aim of this study is to review the indications, the techniques, and the results of SEMS removal in a cohort of patients with malfunctioning stents. All patients who underwent an attempt at endoscopic removal of biliary SEMS over a 5-year period were retrospectively identified. The main indications for SEMS removal were the following: distal migration of the stent or impaction to the duodenum, impaction into the bile-duct wall, tissue ingrowth, and inappropriate length of the stent causing occlusion of intrahepatic ducts. SEMS were removed by using foreign-body forceps or polypectomy snares. Endoscopic removal of 39 SEMS (13 uncovered and 26 covered) was attempted in 29 patients (17 men; mean age, 66 years). SEMS extraction was attempted after a mean of 7.5 months (8.75 months standard deviation) post-SEMS insertion. Removal was successful in 20 patients (68.9%) and in 29 SEMS (74.3%). Covered SEMS were effectively removed more frequently than uncovered ones: 24 of 26 (92.3%) and 5 of 13 (38.4%), respectively (p < 0.05). No major complications were recorded. Multivariate analysis showed that the time interval between insertion and removal, SEMS length, stent-mesh design (zigzag vs. interlaced), and indication for removal were not predictive of success at stent removal. Endoscopic removal of biliary SEMS is feasible and safe in more than 70% of cases. Because only 38% of uncovered SEMS were removable, the presence of a stent covering is the only factor predictive of successful stent extraction. The presence of diffuse and severe ingrowth was the main feature limiting SEMS removal.

  13. A randomized multicenter comparison of hybrid sirolimus-eluting stents with bioresorbable polymer versus everolimus-eluting stents with durable polymer in total coronary occlusion: rationale and design of the Primary Stenting of Occluded Native Coronary Arteries IV study

    Directory of Open Access Journals (Sweden)

    Teeuwen Koen

    2012-12-01

    Full Text Available Abstract Background Percutaneous recanalization of total coronary occlusion (TCO was historically hampered by high rates of restenosis and reocclusions. The PRISON II trial demonstrated a significant restenosis reduction in patients treated with sirolimus-eluting stents compared with bare metal stents for TCO. Similar reductions in restenosis were observed with the second-generation zotarolimus-eluting stent and everolimus-eluting stent. Despite favorable anti-restenotic efficacy, safety concerns evolved after identifying an increased rate of very late stent thrombosis (VLST with drug-eluting stents (DES for the treatment of TCO. Late malapposition caused by hypersensitivity reactions and chronic inflammation was suggested as a probable cause of these VLST. New DES with bioresorbable polymer coatings were developed to address these safety concerns. No randomized trials have evaluated the efficacy and safety of the new-generation DES with bioresorbable polymers in patients treated for TCO. Methods/Design The prospective, randomized, single-blinded, multicenter, non-inferiority PRISON IV trial was designed to evaluate the safety, efficacy, and angiographic outcome of hybrid sirolimus-eluting stents with bioresorbable polymers (Orsiro; Biotronik, Berlin, Germany compared with everolimus-eluting stents with durable polymers (Xience Prime/Xpedition; Abbott Vascular, Santa Clara, CA, USA in patients with successfully recanalized TCOs. In total, 330 patients have been randomly allocated to each treatment arm. Patients are eligible with estimated duration of TCO ≥4 weeks with evidence of ischemia in the supply area of the TCO. The primary endpoint is in-segment late luminal loss at 9-month follow-up angiography. Secondary angiographic endpoints include in-stent late luminal loss, minimal luminal diameter, percentage of diameter stenosis, in-stent and in-segment binary restenosis and reocclusions at 9-month follow-up. Additionally, optical coherence

  14. Self-expandable covered metallic esophageal stent impregnated with beta-emitting radionuclide: an experimental study in canine esophagus

    International Nuclear Information System (INIS)

    Won, Je Hwan; Lee, Jong Doo; Wang, Hee Jung; Kim, Gui-Eon; Kim, Bong Wan; Yim, Hyunee; Han, Sang Keon; Park, Chan H.; Joh, Chul Woo; Kim, Kyung-Hwa; Park, Kyung Bae; Shin, Kyong-Min

    2002-01-01

    Purpose: A specially designed self-expandable covered metallic stent impregnated with the β-emitting radioisotope 166 Ho ( 166 Ho, energy: 1.85 and 1.76 MeV, T((1)/(2)): 26.8 h) was developed at our institute for the purpose of intraluminal palliative brachytherapy, as well as for treating malignant esophageal stricture and swallowing difficulty. The aim of this study was to evaluate the tissue response to brachytherapy and the safety of the radioactive metallic stent with regard to the normal canine esophagus before clinical application. Methods and Materials: 166 Ho was impregnated into the polyurethane membrane (50 μ thickness) covering the outer surface of a self-expandable metallic stent (diameter, 18 mm; length, 40 mm). Stents with radioactivity 4.0-7.8 mCi (Group A, n=15), 1.0-1.8 mCi (Group B, n 5), and 0.5-0.7 mCi (Group C, n=5) were placed in the esophagi of 25 healthy beagle dogs, and the stents were tightly anchored surgically to prevent migration. The estimated radiation dose calculated by Monte Carlo simulation was 194-383 Gy in Group A, 48-90 Gy in Group B, and 23-32 Gy in Group C. The dogs were killed 8-12 weeks after insertion of the stents, and histologic examinations of the esophageal walls were performed. Results: In Group A, 3 of 15 dogs died of wound infection, so specimens were obtained from only 12 dogs; all 12 cases showed esophageal stricture with mucosal ulceration. Microscopically, severe fibrosis and degeneration of the muscular propria were found in 3 dogs, complete fibrosis of the entire esophageal wall was found in 7 dogs, and esophageal fibrosis with radiation damage within periesophageal soft tissue was found in 2 dogs. However, esophageal perforation did not develop, despite extremely high radiation doses. In Group B, glandular atrophy and submucosal fibrosis were found, but the muscular layer was intact. In Group C, no histologic change was found in 3 dogs, but submucosal inflammation and glandular atrophy with intact mucosa

  15. An experimental study on the influence of the intravascular gianturco type stents on the vascular structures

    Energy Technology Data Exchange (ETDEWEB)

    Choe, Yeon Hyeon [Sejong General Hospital, Bucheon (Korea, Republic of); Park, Jae Hyung; Han, Joon Koo; Han, Man Chung; Kim, Chu Wan [College of Medicine, Seoul National University, Seoul (Korea, Republic of)

    1991-07-15

    Twenty-seven Gianturco-type self-expandable stainless steel intravascular stents were placed into the infrarenal abdominal aortas (n=17) and inferior venae cavae (n=10) in 14 mongrel dogs. In 8 aortas, stents were delivered after balloon catheter-induced denudation of the intima, and in 4 out of the 8 aortas, the stents were also placed into the normal sites to compare the neointimal thickness of the normal and denuded sites. Angiography, light microscopic, and scanning electron microscopic examinations were performed after 1 week (n=1), 2 weeks (n=6), 3 weeks (n=5), and 6 weeks (n=2). The patency rate and thrombosis rate were 100% and 35% in the aortas and 100% and 60% in the inferior venae cavae. The aortic stent wires were covered with thin fibrinous membrane after 1 week. Nearly complete transparent neointimal covering was found in the aortas and caval veins after 2 weeks. There was no significant difference in intimal thickness between the denuded and normal aortas after 2 weeks ({rho} =0.51) and 3 weeks ({rho} =0.56). In 4 dogs with caval vein stents, there was evidence of hemorrhage infarction in the lungs. The thrombosis rate of 12 stents with a stent-artery ratio (SAR) of 1.5 or higher was 41%, while there was no thrombus on the 4 stents with SAR 1.2 or lower, except for 1 specimen after 1 week. It is suggested that stents with SAR 1.2 or lower are more suitable. The high thrombosis rate of the inferior venae cavae may be related with slow blood flow.

  16. A Novel Attempt to Standardize Results of CFD Simulations Basing on Spatial Configuration of Aortic Stent-Grafts.

    Directory of Open Access Journals (Sweden)

    Andrzej Polanczyk

    Full Text Available Currently, studies connected with Computational Fluid Dynamic (CFD techniques focus on assessing hemodynamic of blood flow in vessels in different conditions e.g. after stent-graft's placement. The paper propose a novel method of standardization of results obtained from calculations of stent-grafts' "pushing forces" (cumulative WSS--Wall Shear Stress, and describes its usefulness in diagnostic process. AngioCT data from 27 patients were used to reconstruct 3D geometries of stent-grafts which next were used to create respective reference cylinders. We made an assumption that both the side surface and the height of a stent-graft and a reference cylinder were equal. The proposed algorithm in conjunction with a stent-graft "pushing forces" on an implant wall, allowed us to determine which spatial configuration of a stent-graft predispose to the higher risk of its migration. For stent-grafts close to cylindrical shape (shape factor φ close to 1 WSS value was about 267 Pa, while for stent-grafts different from cylindrical shape (φ close to 2 WSS value was about 635 Pa. It was also noticed that deformation in the stent-graft's bifurcation part impaired blood flow hemodynamic. Concluding the proposed algorithm of standardization proved its usefulness in estimating the WSS values that may be useful in diagnostic process. Angular bends or tortuosity in bifurcations of an aortic implant should be considered in further studies of estimation of the risk of implantation failure.

  17. Treatment of forgotten ureteral stents: how much does it really cost? A cost-effectiveness study in 27 patients.

    Science.gov (United States)

    Sancaktutar, Ahmet Ali; Söylemez, Haluk; Bozkurt, Yasar; Penbegül, Necmettin; Atar, Murat

    2012-08-01

    Aim of study was to present costs of forgotten ureteral stents extraction so as to distract attentions of the urologists on this issue. Medical files of 27 accessible patients who referred to our clinics between 2001 and 2010 because of forgotten ureteral stent were retrospectively analyzed. The indwelling time of double-j stents (DJS) was calculated from the time of its insertion. Costs related to radiological investigations, all invasive, and noninvasive interventions, duration of hospital stay, and medical treatments used were calculated. These estimations were based on 2010 prices determined by Turkey Ministry of Health. Mean age of the patients was 31.2 (8-86 years) years. Mean indwelling time of ureteral DJSs was 36.7 months (14-84 months). Seventy-one [extracorporeal shock wave lithotripsy (ESWL), n = 26; invasive/noninvasive interventions, n = 32] procedures were applied for 27 patients. In six patients without incrustation, after a single session of ESWL DJSs could be removed cystoscopically. A various combination of a multimodal therapy was used for other 21 patients. Total financial burden of 27 patients was US $ 34,300. Cost of treatment was estimated to be 6.9-fold (1.8- to 21-fold) higher than an average timely stent extraction. Financial burden of the treatments increased in parallel with the duration of the stent retention (p = 0.001). Management of forgotten DJS is time consuming, difficult, complicated, risky, and costly. Therefore; financial burden, increased labour loss, and impaired quality of life brought by the application of these modalities must not be forgotten.

  18. Comparative Study of Esophageal Self-expandable Metallic Stent Insertion and Gastrostomy Feeding for Dysphagia Caused by Lung Cancer.

    Science.gov (United States)

    Kim, Jihye; Min, Yang Won; Lee, Hyuk; Min, Byung Hoon; Lee, Joon Haeng; Rhee, Poong Lyul; Kim, Jae J

    2018-03-25

    Dysphagia is encountered in a large proportion of patients with lung cancer and is associated with malnutrition and a poor quality of life. This study compared the clinical outcomes of self-expandable metallic stent (SEMS) insertion and percutaneous gastrostomy (PG) feeding for patients with lung cancer and dysphagia. A total of 261 patients with lung cancer, who underwent either SEMS insertion (stent group) or PG (gastrostomy group) as an initial treatment procedure for dysphagia between July 1997 and July 2015 at the Samsung Medical Center, were reviewed retrospectively, and 84 patients with esophageal obstruction were identified. The clinical outcomes, including the overall survival, additional intervention, complications, and post-procedural nutritional status in the two groups, were compared. Among the 84 patients finally analyzed, 68 patients received SEMS insertion and 16 had PG. The stent group had less cervical obstruction and more mid-esophageal obstruction than the gastrostomy group. The Kaplan-Meier curves revealed similar overall survival in the two groups. Multivariate analysis showed that the two modalities had similar survival rates (PG compared with SEMS insertion, hazard ratio 0.682, p=0.219). Fifteen patients (22.1%) in the stent group received additional intervention, whereas there was no case in the gastrostomy group (p=0.063). The decrease in the serum albumin level after the procedure was lower in the gastrostomy group than in the stent group (-0.20±0.54 g/dL vs. -0.65±0.57 g/dL, p=0.013). SEMS insertion and PG feeding for relieving dysphagia by lung cancer had a comparable survival outcome. On the other hand, PG was associated with a better nutritional status.

  19. Endovascular treatment for extrahepatic portal vein bifurcation stenosis after a Whipple procedure using the kissing stents technique.

    Science.gov (United States)

    Zhang, Wen-guang; Liu, Dong-mei; Li, Zhen; Wang, Yan-Li; Ding, Peng-xu; Zhou, Peng-li; Wang, Zhong-gao; Han, Xin-wei

    2014-01-01

    A 57-year-old man presented with a rare extrahepatic portal vein bifurcation scar stenosis involving the proximal splenic vein and superior mesenteric vein after a Whipple procedure. He was treated with endovascular coil embolization for the gastroesophageal varices and kissing stents for the portal vein bifurcation stenosis. This case illustrates a rarely seen complication after the Whipple procedure and a novel management strategy that can be considered in the management of this complex disease. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. No association between metal allergy and cardiac in-stent restenosis in patients with dermatitis-results from a linkage study

    DEFF Research Database (Denmark)

    Thyssen, Jacob P; Engkilde, Kåre; Menné, Torkil

    2011-01-01

    Background. Percutaneous coronary intervention (PCI) with implantation of a metal stent is a common procedure performed in patients with symptomatic ischaemic heart disease. Intracoronary stents typically have a backbone of stainless steel, which contains nickel, chromium, and molybdenum, and it ......Background. Percutaneous coronary intervention (PCI) with implantation of a metal stent is a common procedure performed in patients with symptomatic ischaemic heart disease. Intracoronary stents typically have a backbone of stainless steel, which contains nickel, chromium, and molybdenum......, and it remains unclear whether individuals who are allergic to these metals have an increased risk of restenosis after PCI with stent implantation. Objectives. To further evaluate whether dermatitis patients with nickel and/or chromium allergy had an increased risk of developing cardiac in-stent restenosis...... with stainless steel stents. Methods. An individual-level linkage study was performed to identify dermatitis patients who had been patch tested with the European baseline series between 1979 and 2007 at Gentofte University Hospital (N = 18794) and who had also undergone PCI at some point in a Danish hospital...

  1. Preoperative JJ stent placement in ureteric and renal stone treatment: results from the Clinical Research Office of Endourological Society (CROES) ureteroscopy (URS) Global Study.

    Science.gov (United States)

    Assimos, Dean; Crisci, Alfonso; Culkin, Daniel; Xue, Wei; Roelofs, Anita; Duvdevani, Mordechai; Desai, Mahesh; de la Rosette, Jean

    2016-04-01

    To compare outcomes of ureteric and renal stone treatment with ureteroscopy (URS) in patients with or without the placement of a preoperative JJ stent. The Clinical Research Office of the Endourological Society (CROES) URS Global Study collected prospective data for 1 year on consecutive patients with ureteric or renal stones treated with URS at 114 centres around the world. Patients that had had preoperative JJ stent placement were compared with those that did not. Inverse-probability-weighted regression adjustment (IPWRA) was used to examine the effect of preoperative JJ stent placement on the stone-free rate (SFR), length of hospital stay (LOHS), operative duration, and complications (rate and severity). Of 8 189 patients with ureteric stones, there were 978 (11.9%) and 7 133 patients with and without a preoperative JJ stent, respectively. Of the 1 622 patients with renal stones, 590 (36.4%) had preoperative stenting and 1 002 did not. For renal stone treatment, preoperative stent placement increased the SFR and operative time, and there was a borderline significant decrease in intraoperative complications. For ureteric stone treatment, preoperative stent placement was associated with longer operative duration and decreased LOHS, but there was no difference in the SFR and complications. One major limitation of the study was that the reason for JJ stent placement was not identified preoperatively. The placement of a preoperative JJ stent increases SFRs and decreases complications in patients with renal stones but not in those with ureteric stones. © 2015 The Authors BJU International © 2015 BJU International Published by John Wiley & Sons Ltd.

  2. Comparison of a New Polytetrafluoroethylene-Covered Metallic Stent to a Noncovered Stent in Canine Ureters

    International Nuclear Information System (INIS)

    Chung, Hwan-Hoon; Lee, Seung Hwa; Cho, Sung Bum; Park, Hong Suk; Kim, Young Sik; Kang, Byung Chul; Frisoli, Joan K.; Razavi, Mahmood K.

    2008-01-01

    The aim of this study was to determine the feasibility of using a newly designed polytetrafluoroethylene (PTFE)-covered metallic stent in the ureter by comparing its effectiveness with that of the noncovered stent in a canine model. We placed 14 stents in the ureters of seven mongrel dogs that weighed 30-40 kg each. The covered and noncovered stents were deployed in the right and left ureters, respectively, of six dogs. In the seventh dog, a covered stent and a double-J catheter were inserted in the right ureter, and a covered stent only was inserted in the left ureter. The first six dogs were sacrificed at 5, 10, and 15 weeks after deployment of the stents (two for each follow-up period), and the seventh dog was sacrificed at 30 weeks. There was no migration or poor expansion of any of the stents observed on plain radiography. On intravenous pyelogram and retrograde pyelogram, all of the covered stents at each follow-up period had patent lumens at the stented segments without hydronephrosis, and the passage of contrast material through it was well preserved. The noncovered stents in the dogs sacrificed at 5 and 10 weeks and one of the two dogs sacrificed at 15 weeks showed near-complete occlusion of the stent lumen due to ingrowth of the soft tissue, and severe hydronephrosis was also noted. The noncovered stent in the other dog sacrificed at 15 weeks showed the passage of contrast material without hydronephrosis, but the lumen of the stent was still nearly occluded by the soft tissue. There was no evidence of hydronephrosis or passage disturbance of the contrast material in both ureters of the dog sacrificed at 30 weeks. We conclude that the newly designed PTFE-covered stent effectively prevented the luminal occlusion caused by urothelial hyperplasia compared to the near-total occlusion of the noncovered stents, and no migration of the covered stents was noted

  3. Treatment of carotid artery aneurysms with covered stents; Aneurysmabehandlung der Arteria carotis interna mit gecoverten Stents

    Energy Technology Data Exchange (ETDEWEB)

    Rohr, A.; Alfke, K.; Doerner, L.; Jansen, O. [UKSH Kiel (Germany). Neurochirurgie Neuroradiologie; Bartsch, T.; Stingele, R. [UKSH Kiel (Germany). Neurologie

    2007-10-15

    Purpose: Evaluation of the use of covered stents in treating pseudoaneurysms of the cervical and intracranial/extradural carotid artery and determination of the periprocedural and short- to mid-term complication rate. Materials and Methods: 8 patients with 9 spontaneous dissecting aneurysms of the cervical carotid artery - 5 of which were symptomatic - plus one patient with ofthalmoplegia due to an aneurysm of the cavernous carotid artery were studied. While the latter was treated with a PTFE-covered balloon-mounted stainless steel stent (Jostent/Graftmaster), a self-expanding PTFE-covered Nitonol Stent (Symbiot) was used in all other cases. Intervention was performed with local anesthesia. Aspirin and Clopidogrel were both used as antiplatelet drugs. Clinical signs and symptoms and vascular imaging with DS, MR, CT angiography and ultrasound were recorded during patient follow-up, with a mean follow-up period of 14.6 months (4 - 30). Results: We were able to treat 8 out of 10 aneurysms (80 %) using covered stents. The aneurysms were immediately occluded and the associated stenoses of the parent vessel were eliminated. No clinically relevant complications occurred during the procedure or in the follow-up interval. In two cases, elongation of the carotid artery prevented the stent from being positioned over the aneurysm neck. These cases were shown to be stable with the use of antiplatelet drugs. Conclusion: Covered stents can be used in the treatment of pseudoaneurysms of the carotid artery as an alternative to long-term antithrombotic medication or surgery. In our study treatment was effective (80 %) and free of complications in the short- and mid-term follow-up. Possible indications, technique and the use of imaging modalities for patient follow-up are discussed. (orig.)

  4. A prospective group sequential study evaluating a new type of fully covered self-expandable metal stent for the treatment of benign biliary strictures (with video).

    Science.gov (United States)

    Poley, Jan-Werner; Cahen, Djuna L; Metselaar, Herold J; van Buuren, Henk R; Kazemier, Geert; van Eijck, Casper H J; Haringsma, Jelle; Kuipers, Ernst J; Bruno, Marco J

    2012-04-01

    Fully-covered self expandable metal stents (fcSEMSs) are an alternative to progressive plastic stenting for the treatment of benign biliary strictures (BBS) with the prospect of a higher treatment efficacy and the need for fewer ERCPs, thereby reducing the burden for patients and possibly costs. Key to this novel treatment is safe stent removal. To investigate the feasibility and safety of stent removal of a fcSEMS with a proximal retrieval lasso: a long wire thread integrated in the proximal ends of the wire mesh that hangs freely in the stent lumen. Pulling it enables gradual removal of the stent inside-out. A secondary aim was success of stricture resolution. Non-randomized, prospective follow-up study with 3 sequential cohorts of 8 patients with BBS. Academic tertiary referral center. Eligible patients had strictures either postsurgical (post-cholecystectomy (LCx) or liver transplantation (OLT)), due to chronic pancreatitis (CP), or papillary stenosis (PF). Strictures had to be located at least 2 cm below the liver hilum. All patients had one plastic stent in situ across the stricture and had not undergone previous treatment with either multiple plastic stents or fcSEMS. The first cohort of patients underwent stent placement for 2 months, followed by 3 months if the stricture had not resolved. The second and third cohort started with 3 months and 4 months, respectively, both followed by another 4 months if indicated. Treatment success was defined by stricture resolution at cholangiography, the ability to pass an inflated extraction balloon and clinical follow-up (at least 6 months). safety of stent removal. Secondary outcomes were complications and successful stricture resolution. A total of 23 patients (11 female; 20-67 yrs) were eligible for final analysis. One patient developed a malignant neuroendocrine tumor in the setting of CP. Strictures were caused by CP (13), OLT (6), LCx (3) and PF (1). In total 39 fcSEMS were placed and removed. Removals were easy

  5. Experimental absorbable stent permits airway remodeling.

    Science.gov (United States)

    Liu, Kuo-Sheng; Liu, Yun-Hen; Peng, Yi-Jie; Liu, Shih-Jung

    2011-02-01

    Despite metallic and silicone stents being effective in treating various airway lesions, many concerns still remain. A bioresorbable stent that scaffolds the airway lumen and dissolves after the remodeling process is completed has advantages over metallic and silicone stents. We designed and fabricated a new mesh-type bioresorbable stent with a backbone of polycaprolactone (PCL), and evaluated its safety and biocompatibility in a rabbit trachea model. The PCL stent was fabricated by a laboratory-made microinjection molding machine. In vitro mechanical strength of the PCL stents was tested and compared to that of commercial silicone stents. The bioresorbable stents were surgically implanted into the cervical trachea of New Zealand white rabbits (n=6). Animals received bronchoscopic examination at 1, 2, 4, 8, and 12 weeks after surgery. Histological examination was completed to evaluate the biocompatibility of the stents. No animals died during the period of study. Distal stent migration was noted in 1 rabbit. In-stent secretion accumulation was found in 2 rabbits. Histological examination showed intact ciliated epithelium and marked leukocyte infiltration in the submucosa of the stented area at 10 and 28 weeks. Stent degradation was minimal, and the mechanical strength was well preserved at the end of 33 weeks. These preliminary findings showed good safety and biocompatibility of the new PCL stent when used in the airway remodeling. PCL could be a promising bioresorbable material for stent design if prolonged degradation time is required. Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  6. The influence of stent design on neointimal hyperplasia of an aortic stent covering the visceral arterial ostia: an experimental study in dogs using a self-expandable nitinol stent

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Yong Hu; Chung, Jin Wook; Choi, Seung Hong; Kim, Kwang Gi; Kim, Hyo Cheol; So, Young Ho; Jae, Hwan Jun; Lee, Whal; Park, Jae Hyung [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2008-05-15

    To assess the influence of stent design [interlacing (type A) vs. crossing method (type B)] on neointimal hyperplasia using a self-expandable nitinol stent, which crosses the side branches of the abdominal aorta. In seven mongrel dogs, nitinol stents with type A and B intersections were placed in the abdominal aorta across the main branches: 4 Niti-Ms and 3 Niti-Ds. Two months after the stent placement, a DSA was performed for a stent patency evaluation, followed by the extraction of the aortas. The degree of neointimal formation along the wire was evaluated by calculating the area ratio of intimal hyperplasia (type A vs. B). A Student's t-test was employed to investigate the differences in the neointimal hyperplasia between blood types A and B. The total number of wire intersections overlain at the ostia branch ostia was 23 for type A and 36 for type B. The area ratio of the neointimal hyperplasia, for a given area, was 29.09 {+-} 10.82% (type A) and 13.80 {+-} 6.94% (type B) ({rho} < 0.0001)]. Furthermore, the area ratios of the neointimal hyperplasia per area of stent-wire in the given area were 138.38 {+-} 10.84% (type A). 87.58 {+-} 7.36% (type B) ({rho} = 0.0002). In conclusion the interlacing pattern vs. the crossing pattern showed a higher level of neointimal formation than the crossing pattern.

  7. The influence of stent design on neointimal hyperplasia of an aortic stent covering the visceral arterial ostia: an experimental study in dogs using a self-expandable nitinol stent

    International Nuclear Information System (INIS)

    Yin, Yong Hu; Chung, Jin Wook; Choi, Seung Hong; Kim, Kwang Gi; Kim, Hyo Cheol; So, Young Ho; Jae, Hwan Jun; Lee, Whal; Park, Jae Hyung

    2008-01-01

    To assess the influence of stent design [interlacing (type A) vs. crossing method (type B)] on neointimal hyperplasia using a self-expandable nitinol stent, which crosses the side branches of the abdominal aorta. In seven mongrel dogs, nitinol stents with type A and B intersections were placed in the abdominal aorta across the main branches: 4 Niti-Ms and 3 Niti-Ds. Two months after the stent placement, a DSA was performed for a stent patency evaluation, followed by the extraction of the aortas. The degree of neointimal formation along the wire was evaluated by calculating the area ratio of intimal hyperplasia (type A vs. B). A Student's t-test was employed to investigate the differences in the neointimal hyperplasia between blood types A and B. The total number of wire intersections overlain at the ostia branch ostia was 23 for type A and 36 for type B. The area ratio of the neointimal hyperplasia, for a given area, was 29.09 ± 10.82% (type A) and 13.80 ± 6.94% (type B) (ρ < 0.0001)]. Furthermore, the area ratios of the neointimal hyperplasia per area of stent-wire in the given area were 138.38 ± 10.84% (type A). 87.58 ± 7.36% (type B) (ρ = 0.0002). In conclusion the interlacing pattern vs. the crossing pattern showed a higher level of neointimal formation than the crossing pattern

  8. Silent ischemia after neuroprotected percutaneous carotid stenting: a diffusion-weighted MRI study.

    Science.gov (United States)

    Piñero, P; González, A; Mayol, A; Martínez, E; González-Marcos, J R; Boza, F; Cayuela, A; Gil-Peralta, A

    2006-01-01

    To assess by diffusion-weighted MR imaging (DWI) the efficacy of cerebral protection devices in avoiding embolization and new ischemic lesions in patients with severe internal carotid artery (ICA) stenosis undergoing carotid artery stent placement (CAS). One hundred sixty-two CASs in the extracranial ICA were performed with the use of distal filters. Mean age of the patients was 68.5 years (range, 33-86) and 122 patients (75.3%) were symptomatic. MR imaging was performed in all patients during the 3-day period before CAS, and DWI was obtained within 24 hours after the procedure. Ninety-five patients (58.6%) were monitored by transcranial Doppler ultrasonography for microemboli detection in the territory of the middle cerebral artery (MCA), ipsilateral to the vessel being treated. Twenty-eight patients (17.3%) showed 58 new ischemic foci in DWI, and 13 patients (46.4%) had multiple foci. Location of new lesions was mainly in the vascular territory supplied by the treated vessel (19 patients; 67.9%), but also in the contralateral MCA (1 patient; 3.6%), and the posterior fossa (4 patients; 14.3%). A significant relationship (P neuroprotected CAS. Appearance of new ischemic lesions were only significantly related to the occurrence of TIA but not to the number of MES registered or other variables. Despite the encouraging results, the incidence of new ischemic lesions should promote research for safer techniques and devices.

  9. The Use of Biodegradable Stents in Malignant Oesophageal Strictures for the Treatment of Dysphagia Before Neoadjuvant Treatment or Radical Radiotherapy: A Feasibility Study

    Energy Technology Data Exchange (ETDEWEB)

    Krokidis, Miltiadis, E-mail: mkrokidis@hotmail.com; Burke, Chris; Spiliopoulos, Stavros; Gkoutzios, Panos [Guy' s and St. Thomas' NHS Trust, St Thomas' Hospital, Department of Radiology (United Kingdom); Hynes, Orla [Guy' s and St. Thomas' NHS Trust, Department of Surgery (United Kingdom); Ahmed, Irfan; Dourado, Renato; Sabharwal, Tarun [Guy' s and St. Thomas' NHS Trust, St Thomas' Hospital, Department of Radiology (United Kingdom); Mason, Robert [Guy' s and St. Thomas' NHS Trust, Department of Surgery (United Kingdom); Adam, Andreas [Guy' s and St. Thomas' NHS Trust, St Thomas' Hospital, Department of Radiology (United Kingdom)

    2013-08-01

    PurposeTo evaluate the clinical results of the use of biodegradable oesophageal stents in malignant strictures.MethodsEleven patients were included in this prospective analysis in which a woven polydioxanone biodegradable oesophageal stent was used. The inclusion criterion was that the patient underwent neoadjuvant treatment or radical radiotherapy after the stent insertion. Primary end points were dysphagia score at discharge, stent patency, and complication rate. Secondary end points were overall survival and surgical outcome of surgery.ResultsThere was a 100 % procedure technical success rate. Early complications occurred in three patients resulting in failure to restore oral nutrition. In the remaining eight patients, dysphagia was significantly improved at discharge. Mean stent patency rate in this group was 71.5 days. Stent dysfunction occurred in five of eight patients (62.5 %); in two of five patients this was due to local inflammatory reaction, and in three of five patients it was due to tumour growth after a mean time of 97.8 days, and a new metallic stent was consequently placed in four of five patients. One patient was successfully treated with esophagectomy. At the end of follow-up (mean time 102.1 days), three of eight stents were patent. The overall patient survival rate was 81.8 %.ConclusionAlthough short-term dysphagia scores improved, biodegradable stents do not appear to offer a clear beneficial effect in most cases of malignant strictures, particularly due to a local inflammatory reaction that may be induced. Technical improvement of the device and delineation of the patient group that would benefit from its use is necessary if further studies are to be conducted in the future.

  10. Cost effectiveness of drug eluting coronary artery stenting in a UK setting: cost-utility study.

    Science.gov (United States)

    Bagust, A; Grayson, A D; Palmer, N D; Perry, R A; Walley, T

    2006-01-01

    To assess the cost effectiveness of drug eluting stents (DES) compared with conventional stents for treatment of symptomatic coronary artery disease in the UK. Cost-utility analysis of audit based patient subgroups by means of a simple economic model. Tertiary care. 12 month audit data for 2884 patients receiving percutaneous coronary intervention with stenting at the Cardiothoracic Centre Liverpool between January 2000 and December 2002. Risk of repeat revascularisation within 12 months of index procedure and reduction in risk from use of DES. Economic modelling was used to estimate the cost-utility ratio and threshold price premium. Four factors were identified for patients undergoing elective surgery (n = 1951) and two for non-elective surgery (n = 933) to predict risk of repeat revascularisation within 12 months. Most patients fell within the subgroup with lowest risk (57% of the elective surgery group with 5.6% risk and 91% of the non-elective surgery group with 9.9% risk). Modelled cost-utility ratios were acceptable for only one group of high risk patients undergoing non-elective surgery (only one patient in audit data). Restricting the number of DES for each patient improved results marginally: 4% of stents could then be drug eluting on economic grounds. The threshold price premium justifying 90% substitution of conventional stents was estimated to be 112 pound sterling (212 USD, 162 pound sterling) (sirolimus stents) or 89 pound sterling (167 USD, 130 pound sterling) (paclitaxel stents). At current UK prices, DES are not cost effective compared with conventional stents except for a small minority of patients. Although the technology is clearly effective, general substitution is not justified unless the price premium falls substantially.

  11. Placement of an implantable port catheter in the biliary stent: an experimental study in dogs

    International Nuclear Information System (INIS)

    Ko, Gi Young; Lee, Im Sick; Choi, Won Chan

    2004-01-01

    To investigate the feasibility of port catheter placement following a biliary stent placement. We employed 14 mongrel dogs as test subject and after the puncture of their gaIl bladders using sonographic guidance, a 10-mm in diameter metallic stent was placed at the common duct. In 12 dogs, a 6.3 F port catheter was placed into the duodenum through the common duct and a port was secured at the subcutaneous space following stent placement. As a control group, an 8.5 F drain tube was placed into the gallbladder without port catheter placement in the remaining two dogs. Irrigation of the bile duct was performed every week by injection of saline into the port, and the port catheter was replaced three weeks later in two dogs. Information relating to the success of the procedure, complications and the five-week follow-up cholangiographic findings were obtained. Placement of a biliary stent and a port catheter was technically successful in 13 (93%) dogs, while stent migration (n=3), gallbladder rupture (n=1) and death (n=5) due to subcutaneous abscess and peritonitis also occurred. The follow-up was achieved in eight dogs (seven dogs with a port catheter placement and one dog with a drain tube placement). Irrigation of the bile duct and port catheter replacement were successfully achieved without any complications. Cholangiograms obtained five weeks after stent placement showed diffuse biliary dilation with granulation tissue formation. However, focal biliary stricture was seen in one dog with stent placement alone. Placement of a port catheter following biliary stent placement seems to be feasible. However, further investigation is necessary to reduce the current complications

  12. Placement of an implantable port catheter in the biliary stent: an experimental study in dogs

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Gi Young; Lee, Im Sick; Choi, Won Chan [Asan Medical Center, Seoul (Korea, Republic of)

    2004-04-01

    To investigate the feasibility of port catheter placement following a biliary stent placement. We employed 14 mongrel dogs as test subject and after the puncture of their gaIl bladders using sonographic guidance, a 10-mm in diameter metallic stent was placed at the common duct. In 12 dogs, a 6.3 F port catheter was placed into the duodenum through the common duct and a port was secured at the subcutaneous space following stent placement. As a control group, an 8.5 F drain tube was placed into the gallbladder without port catheter placement in the remaining two dogs. Irrigation of the bile duct was performed every week by injection of saline into the port, and the port catheter was replaced three weeks later in two dogs. Information relating to the success of the procedure, complications and the five-week follow-up cholangiographic findings were obtained. Placement of a biliary stent and a port catheter was technically successful in 13 (93%) dogs, while stent migration (n=3), gallbladder rupture (n=1) and death (n=5) due to subcutaneous abscess and peritonitis also occurred. The follow-up was achieved in eight dogs (seven dogs with a port catheter placement and one dog with a drain tube placement). Irrigation of the bile duct and port catheter replacement were successfully achieved without any complications. Cholangiograms obtained five weeks after stent placement showed diffuse biliary dilation with granulation tissue formation. However, focal biliary stricture was seen in one dog with stent placement alone. Placement of a port catheter following biliary stent placement seems to be feasible. However, further investigation is necessary to reduce the current complications.

  13. [Experimental study of an intratracheal stent made of shape memory alloy].

    Science.gov (United States)

    Yoshimura, M; Tsugawa, C; Tsubota, N

    1994-11-01

    To develop a new prosthesis for treating tracheal stenosis and tracheobronchomalacia, we examined the usefulness of an intratracheal stent made of shape memory alloy (SMA), a titanium-nickel alloy composed of 50% of each metal. At its recovery temperature (37 degrees C), the SMA stent was designed to recall the memorized shape of a coil with a diameter of 5 or 6 mm and a length of 10 mm. For the present experiment, it was transformed to a smaller coil 3 mm in diameter at a low temperature (-50 degrees C) and then loaded into the prosthesis introducer tube. An experimental model of potentially fatal tracheomalacia was made surgically by cutting and fracturing the tracheal cartilages of rabbits and tracheal collapse was confirmed by rigid bronchoscope. The introducer tube with the SMA stent was inserted and then the prosthesis was advanced into the collapsed segment of the trachea using the stent pusher. The SMA stent warmed bo body temperature and recovered its memorized shape after 1-2 min. In 3 out of 8 rabbits, follow-up bronchoscopy performed at 6, 8, and 10 months after implantation revealed satisfactory patency of the SMA stent and the trachea. After follow-up, 3 animals were sacrificed for histological observation, which showed little proliferation of granulation tissue and no dislocation of the SMA stent from the malacic portion. The remaining 5 rabbits have been followed for 18-24 months and are doing well. We conclude that the SMA stent maintains good tracheal patency, causes little reaction in the tracheal wall, and is easy to handle. Thus, it shows the potential for clinical application.

  14. Percutaneous biliary drainage and stenting

    International Nuclear Information System (INIS)

    Totev, M.

    2012-01-01

    Full text: Percutaneous transhepatic cholangiography (PTC) is an X-ray or US guided procedure that involves the injection of a contrast material directly into the bile ducts inside the liver to produce pictures of them. If a blockage or narrowing is found, additional procedures may be performed: 1. insertion of a catheter to drain excess bile out of the body or both - internal and external; 2. plastic endoprothesis placement; 3. self-expandable metal stents placement to help open bile ducts or to bypass an obstruction and allow fluids to drain. Current percutaneous biliary interventions include percutaneous transhepatic cholangiography (PTC) and biliary drainage to manage benign and malignant obstructions. Internal biliary stents are either plastic or metallic, and various types of each kind are available. Internal biliary stents have several advantages. An external tube can be uncomfortable and have a psychological disadvantage. An internal stent prevents the problems related to external catheters, for example, pericatheter leakage of bile and the need for daily flushing. The disadvantages include having to perform endoscopic retrograde cholangiopancreatography (ERCP) or new PTC procedures to obtain access in case of stent obstruction. Better patency rates are reported with metallic than with plastic stents in cases of malignant obstruction, though no effect on survival is noted. Plastic internal stents are the cheapest but reportedly prone to migration. Metallic stents are generally not used in the treatment of benign disease because studies have shown poor long-term patency rates. Limited applications may include the treatment of patients who are poor surgical candidates or of those in whom surgical treatment fails. Most postoperative strictures are treated surgically, though endoscopic and (less commonly) percutaneous placement of nonmetallic stents has increasingly been used in the past few years. Now there are some reports about use of biodegradable biliary

  15. In vitro stent lumen visualisation of various common and newly developed femoral artery stents using MR angiography at 1.5 and 3 tesla.

    Science.gov (United States)

    Syha, R; Ketelsen, D; Kaempf, M; Mangold, S; Sixt, S; Zeller, T; Springer, F; Schick, F; Claussen, C D; Brechtel, K

    2013-02-01

    To evaluate stent lumen assessment of various commonly used and newly developed stents for the superficial femoral artery (SFA) using MR angiography (MRA) at 1.5 and 3 T. Eleven nitinol stents and one cobalt-chromium stent were compared regarding stent lumen visualisation using a common three-dimensional MRA sequence. Maximum visible stent lumen width and contrast ratio were analysed in three representative slices for each stent type. A scoring system for lumen visualisation was applied. Nitinol stents showed significantly better performance than the cobalt chromium stent (P stent lumen ranged between 43.4 and 95.5 %, contrast ratio between 7.2 and 110.6 %. Regarding both field strengths, seven of the nitinol stents were classified as "suitable". Three nitinol stents were "limited", and one nitinol stent and the cobalt chromium stent were "not suitable". Intraluminal loss of signal and artefacts of most of the SFA stents do not markedly limit assessment of stent lumen by MRA at 1.5 and 3 T. MRA can thus be considered a valid technique for detection of relevant in-stent restenosis. Applied field strength does not strongly influence stent lumen assessment in general, but proper choice of field strength might be helpful.

  16. A comparative reliability and performance study of different stent designs in terms of mechanical properties: foreshortening, recoil, radial force, and flexibility.

    Science.gov (United States)

    Kim, Dong Bin; Choi, Hyuk; Joo, Sang Min; Kim, Han Ki; Shin, Jae Hee; Hwang, Min Ho; Choi, Jaesoon; Kim, Dong-Gon; Lee, Kwang Ho; Lim, Chun Hak; Yoo, Sun Kook; Lee, Heung-Man; Sun, Kyung

    2013-04-01

    This study seeks to improve the mechanical performance of stents by conducting reliability performance testing and finite element method (FEM)-based simulations for coronary stents. Three commercially available stent designs and our own new design were tested to measure the factors affecting performance, specifically foreshortening, recoil, radial force, and flexibility. The stents used in the present experiments were 3 mm in working diameter and 18 mm of working length. The results of the experiments indicate that the foreshortening of stents A, B, C, and our new design, D, was equivalent to 2.25, 0.67, 0.46, and 0.41%, respectively. The recoil of stents A, B, C, and D was 6.00, 4.35, 3.50, and 4.36%, respectively. Parallel plate radial force measurements were A, 3.72 ± 0.28 N; B, 3.81 ± 0.32 N; C, 4.35 ± 0.18 N; and D, 4.02 ± 0.24 N. Radial forces determined by applying uniform pressure in the circumferential direction were A, 28.749 ± 0.81 N; B, 32.231 ± 1.80 N; C, 34.522 ± 3.06 N; and D, 42.183 ± 2.84 N. The maximum force of crimped stent at 2.2-mm deflection was 1.01 ± 0.08 N, 0.82 ± 0.08 N, 0.92 ± 0.12 N, and 0.68 ± 0.07 N for each of stents A, B, C and D. The results of this study enabled us to identify several factors to enhance the performance of stents. In comparing these stents, we found that our design, stent D, which was designed by a collaborative team from seven universities, performed better than the commercial stents across all parameter of foreshortening, recoil, radial force, and flexibility. © 2013, Copyright the Authors. Artificial Organs © 2013, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  17. Results of the new nitinol self-expandable stents for distal biliary structures

    NARCIS (Netherlands)

    Smits, M.; Huibregtse, K.; Tytgat, G.

    1995-01-01

    The nitinol stent is a self-expandable spiral stent made of nickel-titanium alloy. We performed a pilot study to evaluate the method of stent insertion and stent efficacy. Twenty-eight patients with irresectable malignancy had nitinol stents inserted for obstructive jaundice due to distal biliary

  18. Transjugular Intrahepatic Portosystemic Shunt Flow Reduction with Adjustable Polytetrafluoroethylene-Covered Balloon-Expandable Stents Using the “Sheath Control” Technique

    Energy Technology Data Exchange (ETDEWEB)

    Blue, Robert C., E-mail: Robert.c.blue@gmail.com; Lo, Grace C.; Kim, Edward; Patel, Rahul S.; Scott Nowakowski, F.; Lookstein, Robert A.; Fischman, Aaron M. [Icahn School of Medicine at Mount Sinai, Interventional Radiology Section, Department of Radiology (United States)

    2016-06-15

    PurposeA complication of transjugular intrahepatic portosystemic shunts (TIPS) placement is refractory portosystemic encephalopathy (PSE) often requiring TIPS reduction. We report the results of a “sheath control technique” utilizing constraining sheaths during deployment of polytetrafluoroethylene (PTFE)-covered balloon-expandable stents, minimizing stent migration, and providing additional procedural control.MethodsTIPS reduction was performed in 10 consecutive patients for PSE using Atrium iCast covered stents (Atrium Maquet Getinge Group, Germany). Within the indwelling TIPS stent, a 9 mm × 59 mm iCast stent was deployed with 2 cm exposed from the sheath’s distal end and the majority of the stent within the sheath to create the distal hourglass shape. During balloon retraction, the stent was buttressed by the sheath. The proximal portion of the stent was angioplastied to complete the hourglass configuration, and the central portion of the stent was dilated to 5 mm. Demographics, pre- and post-procedure laboratory values, and outcomes were recorded.ResultsTen patients underwent TIPS reduction with 100 % technical success. There was no stent migration during stent deployment. All patients experienced initial improvement of encephalopathy. One patient ultimately required complete TIPS occlusion for refractory PSE, and another developed TIPS occlusion 36 days post-procedure. There was no significant trend toward change in patients’ MELD scores immediately post-procedure or at 30 days (p = 0.46, p = 0.47, respectively).ConclusionTIPS reduction using Atrium iCast PTFE balloon-expandable stents using the “sheath control technique” is safe and effective, and minimizes the risk of stent migration.

  19. Long-Term Results After Simple Versus Complex Stenting of Coronary Artery Bifurcation Lesions Nordic Bifurcation Study 5-Year Follow-Up Results

    DEFF Research Database (Denmark)

    Maeng, M.; Holm, N. R.; Erglis, A.

    2013-01-01

    Objectives This study sought to report the 5-year follow-up results of the Nordic Bifurcation Study. Background Randomized clinical trials with short-term follow-up have indicated that coronary bifurcation lesions may be optimally treated using the optional side branch stenting strategy. Methods...... complex strategy of planned stenting of both the main vessel and the side branch. (C) 2013 by the American College of Cardiology Foundation...

  20. Preliminary Report of Carotid Artery Stenting Using a Tapered Stent

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Chang Woo; Kim, Dong Hyun; Hong, Seung; Jeong; Kim, Young Suk; Byun, Joo Nam; Oh, Jae Hee [Dept. of Radiology, Chosun University College of Medicine, Gwangju (Korea, Republic of); Ahn, Seong Hwan [Dept. of Neurology, Chosun University College of Medicine, Gwangju (Korea, Republic of)

    2011-10-15

    To analyze the results of carotid artery stenting using a tapered stent and to evaluate the effectiveness of the tapered stent compared to previously reported studies using non-tapered stents. From October 2008 to August 2010, elective carotid artery stenting using a tapered stent was attempted in 39 lesions from 36 consecutive patients. Post-procedural complications were evaluated by neurologic symptoms and magnetic resonance imaging. Restenosis or occlusion was evaluated by carotid Doppler ultrasound and computerized tomography with angiography. Newly developed neurologic symptoms were evaluated clinically. The self-expandable tapered stent was placed across the carotid artery stenosis. A total stroke was noted in 3 patients, while a major stroke was noted in 1 patient. On diffusion weighted imaging, new lesions were observed in 15 patients, but 13 patients were clinically silent. Follow-up imaging studies were performed in the 13 clinically silent lesions, and no evidence of restenosis or occlusion was found any of the 13 lesions. During clinical follow-up in 34 lesions from 31 patients, there were newly developed neurological symptoms in only 1 patient.

  1. Study on the effect of location of intracranial arterial stenosis on the safety of stenting

    Directory of Open Access Journals (Sweden)

    Yu-jie SUN

    2017-11-01

    Full Text Available Objective To investigate the effect of location of intracranial arterial stenosis on the safety of intracranial stenting. Methods A total of 73 patients with symptomatic intracranial atherosclerotic stenosis (ICAS were divided into intracranial internal carotid artery (IICA, N = 18, middle cerebral artery (MCA-M1 segment (MCA-M1, N = 11, intracranial vertebral artery (IVA, N = 27 and basilar artery (BA, N = 17. All of them underwent intracranial stenting. The improvement of intracranial arterial stenosis, cerebrovascular complications including perforating events, artery dissection, in-stent thrombosis, distal stent arterial embolism and cerebral hyperperfusion, and neurological complications including transient ischemic attack (TIA, ischemic stroke and intracranial hemorrhage were recorded. Modified Rankin Scale (mRS was used to evaluate the prognosis 30 d after operation. Results A total of 73 stents were implanted in 73 patients (35 Apollo balloon-expandable stents and 38 Wingspan self-expandable stents. Among them, 10 cases (10/18 were treated with Apollo stents and 8 cases (8/18 with Wingspan stents in IICA group, 5 cases (5/11 were treated with Apollo stents and 6 cases (6/11 with Wingspan stents in MCA-M1 group, 16 cases (59.26%, 16/27 were treated with Apollo stents and 11 cases (40.74%, 11/27 with Wingspan stents in IVA group, and 4 cases (4/17 were treated with Apollo stents and 13 cases (13/17 with Wingspan stents in BA group. No significant difference was seen in stent type among 4 groups (χ2 = 7.422, P = 0.201. The stenosis rate of IICA group after treatment [(10.94 ± 1.99%] was significantly improved than before treatment [(90.89 ± 7.71%; t = 69.545, P = 0.000]. The stenosis rate of MCA-M1 group after treatment [(10.37 ± 2.14%] was significantly improved than before treatment [(87.64 ± 9.46%; t = 26.000, P = 0.000]. The stenosis rate of IVA group after treatment [(11.02 ± 1.99% ] was significantly improved than before

  2. The Erasme Study: A Multicenter Study on the Safety and Technical Results of the Palmaz Stent Used for the Treatment of Atherosclerotic Ostial Renal Artery Stenosis

    International Nuclear Information System (INIS)

    Bakker, Jeannette; Goffette, Pierre P.; Henry, Michel; Mali, Willem P.T.M.; Melki, Jean-Pierre; Moss, Jon G.; Rabbia, Claudio; Therasse, Eric; Thomson, Kenneth R.; Thurnher, Siegfried; Vignali, Claudio

    1999-01-01

    Purpose: To assess, in a multicenter setting, safety, technical results, and restenosis rate of the Palmaz stent for treatment of atherosclerotic ostial renal artery stenosis. Methods: Ten centers enrolled 106 patients (120 treated renal artery stenoses) in the study. Patient selection was based on unsuccessful percutaneous transluminal renal angioplasty (residual stenosis ≥ 20%) performed for treatment of ostial stenosis ≥ 50%, in patients with hypertension and/or impaired renal function. Safety was assessed by means of the complication rate, and technical results by the number of successful stent placements and occurrence of restenosis (>50%) at intraarterial angiographic follow-up. Results: Stent placement was successful (n = 112) or partially successful (n = 5) in 117 (98%) arteries. Complications occurred in 19 procedures; seven were of serious clinical significance. Angiographic follow-up was performed in 89 of 117 (76%) cases, at a mean of 8 months (range 2.5-18 months). Fifteen stents (16.9%) showed restenosis (at a mean of 8.5 months), of which 10 were successfully redilated. Conclusion: Renal artery stenting has a high technical success rate, a complication rate comparable to percutaneous transluminal renal angioplasty, and a low rate of restenosis at 8 months angiographic follow-up

  3. [Absorbable coronary stents. New promising technology].

    Science.gov (United States)

    Erbel, Raimund; Böse, Dirk; Haude, Michael; Kordish, Igor; Churzidze, Sofia; Malyar, Nasser; Konorza, Thomas; Sack, Stefan

    2007-06-01

    Coronary stent implantation started in Germany 20 years ago. In the beginning, the progress was very slow and accelerated 10 years later. Meanwhile, coronary stent implantation is a standard procedure in interventional cardiology. From the beginning of permanent stent implantation, research started to provide temporary stenting of coronary arteries, first with catheter-based systems, later with stent-alone technology. Stents were produced from polymers or metal. The first polymer stent implantation failed except the Igaki-Tamai stent in Japan. Newly developed absorbable polymer stents seem to be very promising, as intravascular ultrasound (IVUS) and optical coherence tomography have demonstrated. Temporary metal stents were developed based on iron and magnesium. Currently, the iron stent is tested in peripheral arteries. The absorbable magnesium stent (Biotronik, Berlin, Germany) was tested in peripheral arteries below the knee and meanwhile in the multicenter international PROGRESS-AMS (Clinical Performance and Angiographic Results of Coronary Stenting with Absorbable Metal Stents) study. The first magnesium stent implantation was performed on July 30, 2004 after extended experimental testing in Essen. The magnesium stent behaved like a bare-metal stent with low recoil of 5-7%. The stent struts were absorbed when tested with IVUS. Stent struts were not visible by fluoroscopy or computed tomography (CT) as well as magnetic resonance imaging (MRI). That means, that the magnesium stent is invisible and therefore CT and MRI can be used for imaging of interventions. Only using micro-CT the stent struts were visible. The absorption process could be demonstrated in a patient 18 days after implantation due to suspected acute coronary syndrome, which was excluded. IVUS showed a nice open lumen. Stent struts were no longer visible, but replaced by tissue indicating the previous stent location. Coronary angiography after 4 months showed an ischemia-driven target lesion

  4. Hemodynamic comparison of stent configurations used for aortoiliac occlusive disease.

    Science.gov (United States)

    Groot Jebbink, Erik; Mathai, Varghese; Boersen, Johannes T; Sun, Chao; Slump, Cornelis H; Goverde, Peter C J M; Versluis, Michel; Reijnen, Michel M P J

    2017-07-01

    Endovascular treatment of aortoiliac occlusive disease entails the use of multiple stents to reconstruct the aortic bifurcation. Different configurations have been applied and geometric variations exist, as quantified in previous work. Other studies concluded that specific stent geometry seems to affect patency. These variations may affect local flow patterns, resulting in different wall shear stress (WSS) and oscillating shear index (OSI). The aim of this study was to compare the effect of different stent configurations on flow perturbations (recirculation and fluid stasis), WSS, and OSI in an in vitro setup. Three different stent configurations were deployed in transparent silicone models: bare-metal kissing (BMK) stents, covered kissing (CK) stents, and the covered endovascular reconstruction of the aortic bifurcation (CERAB) configuration. Transparent covered stents were created with polyurethane to enable visualization. Models were placed in a circulation setup under physiologic flow conditions. Time-resolved laser particle image velocimetry techniques were used to quantify the flow, and WSS and OSI were calculated. The BMK configuration did not show flow disturbances at the inflow section, and WSS values were similar to the control. An area of persistent low flow was observed throughout the cardiac cycle in the area between the anatomic bifurcation and neobifurcation. The CK model showed recirculation zones near the inflow area of the stents with a resulting low average WSS value and high OSI. The proximal inflow of the CERAB configuration did not show flow disturbances, and WSS values were comparable to control. Near the inflow of the limbs, a minor zone of recirculation was observed without changes in WSS values. Flow, WSS, and OSI on the lateral wall of the proximal iliac artery were undisturbed in all models. The studied aortoiliac stent configurations have distinct locations where flow disturbances occur, and these are related to the radial mismatch

  5. A clinical study on perforator stroke resulting from Wingspan stent angioplasty for symptomatic intracranial artery stenosis

    International Nuclear Information System (INIS)

    Wang Ziliang; Xu Haowen; Li Tianxiao; Zhu Liangfu; Li Zhaoshuo; Xue Jiangyu; Bai Weixing; Li Li; Guan Sheng

    2011-01-01

    Objective: To evaluate the incidence, potential hazards and effective countermeasure for perforator stroke (PS) resulting from stent angioplasty of symptomatic intracranial artery stenosis. Methods: Peri-operation PS complications of 258 patients receiving Gateway balloon-Wingspan stenting for severe symptomatic intracranial stenosis were analyzed. The incidence, clinical course, and prognosis of PS resulting from stenting were recorded. Special attention was given to the anatomical features, clinical manifestation and video materials of patients with PS. χ 2 test was used for statistics. Results: Two hundred and fifty-five patients received stent angioplasty successfully and 7 patients had PS (incidence rate 2.7%). The patients with basilar artery stenosis had a higher incidence of PS resulting from intracranial stenting (6.1%, 4/66) than patients with middle cerebral artery stenosis (2.5%, 3/118) (χ 2 =2.320, P= 0.025). The potential hazards for PS included preoperative perforator stroke adjacent to the stenotic segment and prominent dissection during operation. Six patients presented symptoms after awake from general anaesthesia and one had symptoms 3 hours after stenting. One deteriorated gradually and the others reached the maximum deficit almost at once. At the follow-up of 3 months, 3 patients were disabled and scored one, two, two by mRS respectively. Conclusion: The incidence of PS resulting from intracranial stenting was low and the prognosis was not disastrous. Stenosis at basilar artery and preoperative perforator stroke adjacent to the stenotic segment were potential risk factors for PS complication. Proper maneuver of angioplasty may decrease the incidence of PS and improve the prognosis. (authors)

  6. Novel self-expandable, stent-based transcatheter pulmonic valve: a preclinical animal study.

    Science.gov (United States)

    Kim, Gi Beom; Lim, Hong-Gook; Kim, Yong Jin; Choi, Eun Young; Kwon, Bo Sang; Jeong, Saeromi

    2014-04-15

    Because transcatheter implantation of pulmonary valve is indicated for limited-size dysfunctional right ventricular outflow tract only as a balloon-expandable stent, we investigated the feasibility of a large-diameter self-expandable valved stent and the durability of the valve after >6 months. We made a nitinol-wire-based, self-expandable valved stent with leaflets made from porcine pericardium. The porcine pericardium was treated with α-galactosidase, glutaraldehyde, and glycine after decellularization. After cutting the inguinal or cervical area, we implanted a valved stent in 12 sheep through the femoral or jugular vein by using an 18-Fr delivery catheter, controlling the catheter handles and hook block under fluoroscopic and echocardiographic guidance. The mean body weight of sheep was 43.9 kg. We successfully implanted valved stents (diameter: 24 mm in 7 sheep, 26 mm in 5 sheep) in good position in 8 sheep, in the main pulmonary artery (PA) in 2 sheep, and in the right ventricular outlet tract (RVOT) in 2 sheep. We sacrificed 8 sheep (6 sheep in good position, 1 sheep in the main PA, and 1 sheep in the RVOT) after >6 months. Five of the 6 sheep implanted in good position showed well-preserved valve morphology at the time of sacrifice. Histologic findings after routine sacrifice showed well-maintained collagen wave structure and no visible calcification in all explanted valve leaflets. Transcatheter implantation of a nitinol-wire-based, self-expandable valved stent in the pulmonic valve was feasible, and stents implanted in good position showed well-preserved valve leaflets with functional competence in the mid-term results. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  7. The diffusion of medical technology, local conditions, and technology re-invention: a comparative case study on coronary stenting.

    Science.gov (United States)

    Hashimoto, Hideki; Noguchi, Haruko; Heidenreich, Paul; Saynina, Olga; Moreland, Abigail; Miyazaki, Shunichi; Ikeda, Shunya; Kaneko, Yoshihiro; Ikegami, Naoki

    2006-12-01

    Innovation of medical technology is a major driving force behind the increase in medical expenditures in developed countries. Previous studies identified that the diffusion of medical technology varied across countries according to the characteristics of regulatory policy and payment systems. Based on Roger's diffusion of innovation theory, this study purported to see how local practice norms, the evolving nature of diffusing technology, and local clinical needs in addition to differences in politico-economic systems would affect the process of innovation diffusion. Taking a case of coronary stenting, an innovative therapeutic technology in early 1990s, we provided a case study of hospital-based data between two teaching high-tech hospitals in Japan and the US for discussion. Stenting began to be widely used in both countries when complementary new technology modified its clinical efficacy, but the diffusion process still differed between the two hospitals due to (1) distinctive payment systems for hospitals and physicians, (2) practice norms in favor of percutaneous intervention rather than bypass surgery that was shaped by payment incentives and cultural attitudes, and (3) local patient's clinical characteristics that the technology had to be tailored for. The case study described the diffusion of stent technology as a dynamic process between patients, physicians, hospitals, health care systems, and technology under global and local conditions.

  8. Endoscopic stent therapy in patients with chronic pancreatitis: a 5-year follow-up study.

    Science.gov (United States)

    Weber, Andreas; Schneider, Jochen; Neu, Bruno; Meining, Alexander; Born, Peter; von Delius, Stefan; Bajbouj, Monther; Schmid, Roland M; Algül, Hana; Prinz, Christian

    2013-02-07

    This study analyzed clinical long-term outcomes after endoscopic therapy, including the incidence and treatment of relapse. This study included 19 consecutive patients (12 male, 7 female, median age 54 years) with obstructive chronic pancreatitis who were admitted to the 2(nd) Medical Department of the Technical University of Munich. All patients presented severe chronic pancreatitis (stage III°) according to the Cambridge classification. The majority of the patients suffered intermittent pain attacks. 6 of 19 patients had strictures of the pancreatic duct; 13 of 19 patients had strictures and stones. The first endoscopic retrograde pancreatography (ERP) included an endoscopic sphincterotomy, dilatation of the pancreatic duct, and stent placement. The first control ERP was performed 4 wk after the initial intervention, and the subsequent control ERP was performed after 3 mo to re-evaluate the clinical and morphological conditions. Clinical follow-up was performed annually to document the course of pain and the management of relapse. The course of pain was assessed by a pain scale from 0 to 10. The date and choice of the therapeutic procedure were documented in case of relapse. Initial endoscopic intervention was successfully completed in 17 of 19 patients. All 17 patients reported partial or complete pain relief after endoscopic intervention. Endoscopic therapy failed in 2 patients. Both patients were excluded from further analysis. One failed patient underwent surgery, and the other patient was treated conservatively with pain medication. Seventeen of 19 patients were followed after the successful completion of endoscopic stent therapy. Three of 17 patients were lost to follow-up. One patient was not available for interviews after the 1(st) year of follow-up. Two patients died during the 3(rd) year of follow-up. In both patients chronic pancreatitis was excluded as the cause of death. One patient died of myocardial infarction, and one patient succumbed to

  9. Stent underexpansion in angiographic guided percutaneous coronary intervention, despite adjunctive balloon post-dilatation, in drug eluting stent era

    Directory of Open Access Journals (Sweden)

    Mehrdad Taherioun

    2014-01-01

    Full Text Available BACKGROUND: Stent underexpansion is the most powerful predictor of long-term stent patency and clinical outcome. The purpose of this study was to evaluate the incidence and predictors of stent underexpansion despite adjunctive post-dilatation with non-compliant balloon. METHODS: After elective coronary stent implantation and adjunctive post-dilatation with non-compliant balloon and optimal angiographic result confirmed by the operator, intravascular ultrasound (IVUS was performed for all the treated lesions. If the treated lesions fulfilled the IVUS criteria, they are considered as the optimal stent group; if not, they are considered as the suboptimal group. RESULTS: From 50 patients enrolled in this study 39 (78% had optimal stent deployment and 11 (22% had suboptimal stent deployment. In the suboptimal group 7 (14% had underexpansion, 2 (4% malposition, and 2 (4% had asymmetry. There were no stent edge dissections detected by IVUS. We did not find any correlation between lesion calcification, ostial lesions, stent length, and stent underexpansion. Stent diameter ≤ 2.75 mm had a strong correlation with stent underexpansion. CONCLUSION: Despite adjunctive post-dilatation with noncompliant balloon, using a relatively small stent diameter was a strong predictor for underexpansion. IVUS guided percutaneous coronary intervention (PCI may be considered for drug eluting stent (DES implantation in relatively small vessels.   Keywords: Stent, Percutaneous Coronary Intervention, Ultrasound, Post-dilatation 

  10. Predictors of stent dysfunction after self-expandable metal stent placement for malignant gastric outlet obstruction: tumor ingrowth in uncovered stents and migration of covered stents.

    Science.gov (United States)

    Hori, Yasuki; Naitoh, Itaru; Hayashi, Kazuki; Ban, Tesshin; Natsume, Makoto; Okumura, Fumihiro; Nakazawa, Takahiro; Takada, Hiroki; Hirano, Atsuyuki; Jinno, Naruomi; Togawa, Shozo; Ando, Tomoaki; Kataoka, Hiromi; Joh, Takashi

    2017-10-01

    Endoscopic metallic stenting is widely accepted as a palliation therapy for malignant gastric outlet obstruction (GOO). However, the predictors of stent dysfunction have not been clarified. We aimed to evaluate the predictors, especially tumor ingrowth in uncovered self-expandable metallic stents (U-SEMS) and migration of covered self-expandable metallic stents (C-SEMS), which are the main causes related to the stent characteristics. In this multicenter retrospective study, we compared patients with U-SEMS and C-SEMS in terms of clinical outcomes, and predictors of stent dysfunction. In total, 252 patients (126 with U-SEMS and 126 with C-SEMS) were enrolled. There were no significant differences in technical success, clinical success, GOO score, or time to stent dysfunction. Tumor ingrowth was significantly more frequent in U-SEMS (U-SEMS, 11.90% vs. C-SEMS, 0.79%; p = 0.002), and stent migration was significantly more frequent for C-SEMS (C-SEMS, 8.73% vs. U-SEMS, 0.79%; p = 0.005). Karnofsky performance status (p = 0.04), no presence of ascites (p = 0.02), and insufficient (stent expansion (p = 0.003) were significantly associated with tumor ingrowth in U-SEMS. Meanwhile, a shorter stent length (p = 0.05) and chemotherapy (p = 0.03) were predictors of C-SEMS migration. Both U-SEMS and C-SEMS are effective with comparable patencies. Tumor ingrowth and stent migration are the main causes of stent dysfunction for U-SEMS and C-SEMS, respectively. With regard to stent dysfunction, U-SEMS might be a good option for patients receiving chemotherapy, while C-SEMS with longer stents for patients in good condition. (Clinical trial registration number: UMIN000024059).

  11. Preoperative biliary drainage by plastic or self-expandable metal stents in patients with periampullary tumors: results of a randomized clinical study

    Science.gov (United States)

    Olsson, Greger; Frozanpor, Farshad; Lundell, Lars; Enochsson, Lars; Ansorge, Christoph; Del Chiaro, Marco; Reuterwall-Hansson, Marcus; Shetye, Alysha; Arnelo, Urban

    2017-01-01

    Background and study aims  Preoperative biliary drainage in patients with periampullary tumors and jaundice has been popularized to improve the quality of life and minimize the risks associated with subsequent radical surgery. The aim of this study was to investigate the possible superiority of self-expandable metal stents (SEMS) over plastic stents, by comparing the amount of bacteria in intraoperatively collected bile and using this variable as a proxy for the efficacy of the respective biliary drainage modalities. Patients and methods  In this randomized clinical trial, 92 patients with obstructive jaundice were enrolled; 45 were allocated to the plastic stent group and 47 to the SEMS group. The primary outcome was the extent and magnitude of biliary bacterial growth at the time of surgical exploration. Secondary outcomes were: macroscopic grading of inflammation of the stented bile ducts, occurrence of adverse events after stenting, stent dysfunction, recognized surgical complexities, and incidence of postoperative complications. Results  The patients were well matched regarding clinical and disease-specific characteristics. At surgery, there were no group differences in the bacterial amount and composition of the bile cultures or the perceived difficulty of surgical dissection. During the preoperative biliary drainage period, more instances of stent dysfunction requiring stent replacement were recorded in the plastic stent group (19 % vs. 0 %; P  = 0.03). Postoperative complications in patients who underwent curative surgery were more common in patients with plastic stents (72 % vs. 52 %), among which clinically significant leakage from the pancreatic anastomoses seemed to predominate (12 % vs. 3.7 %); however, none of these differences in postoperative adverse events reached statistical significance. Conclusion  This randomized clinical study was unable to demonstrate any superiority of SEMS in the efficacy of preoperative bile

  12. The CLEAR-ROAD study: evaluation of a new dual layer micromesh stent system for the carotid artery.

    Science.gov (United States)

    Bosiers, Marc; Deloose, Koen; Torsello, Giovanni; Scheinert, Dierk; Maene, Lieven; Peeters, Patrick; Müller-Hülsbeck, Stefan; Sievert, Horst; Langhoff, Ralf; Bosiers, Michel; Setacci, Carlo

    2016-08-05

    The aim of this study was to evaluate the 30-day clinical outcome of treatment using the Roadsaver carotid stent in non-consecutive subjects at high risk for carotid endarterectomy requiring revascularisation. The CLEAR-ROAD study is a prospective, multinational, single-arm, physician-initiated study planned to include 100 patients in nine centres in Belgium, Italy and Germany. The primary endpoint was the 30-day rate of major adverse events (MAE), defined as the cumulative incidence of any death, stroke or myocardial infarction (MI). The use of embolic protection devices (EPDs) was not mandatory; 31.0% of the patients were symptomatic and in 58.0% of the patients EPDs were used. Technical success was achieved in all cases. The 30-day MAE rate was 2.1% (one patient experienced MI followed by death; another patient experienced a stroke within the first 30 days after procedure). While no statistical analysis could be performed, subgroup data suggested that there were no notable differences in the 30-day MAE rate between symptomatic and asymptomatic patients, or between EPD use. The 30-day clinical outcome of 100 patients treated with a dual layer micromesh carotid stent (Roadsaver) shows promising results. The Roadsaver stent is a safe and effective device for endovascular treatment of subjects at high risk for carotid endarterectomy.

  13. Removal of retrievable self-expandable urethral stents: experience in 58 stents

    International Nuclear Information System (INIS)

    Shin, Ji Hoon; Song, Ho-Young; Kim, Jin Hyoung; Ko, Heung-Kyu; Kim, Yong Jae; Woo, Chul-Woong; Kim, Tae-Hyung; Ko, Gi-Young; Yoon, Hyun-Ki; Sung, Kyu-Bo; Park, Hyungkeun

    2006-01-01

    The purpose of this study was to retrospectively evaluate the safety and efficacy of removing retrievable self-expandable urethral stents using a retrieval hook wire. Under fluoroscopic guidance, the removal of 58 polyurethane or PTFE (polytetrafluoroethylene)-covered stents was attempted in 33 patients using a retrieval hook wire. Indications for removal were elective removal (n=21), stent migration (n=19), formation of tissue hyperplasia around or inside of the stent (n=14), stent deformity (n=3), and severe pain (n=1). The mean time the stents remained in place was 64.8±42.9 days (range, 1-177 days). Fifty-six (97%) of the 58 stents were successfully removed using the retrieval hook wire despite the following difficulties; hook wire disconnection (n=2), untied drawstrings (n=3), and polyurethane membrane disruption/separation (n=4). The removal procedure using a retrieval hook wire failed in two stents (3%) which had migrated into the urinary bladder. One of the two stents with migration into the urinary bladder was removed using a snare through the cystostomy route. The overall complication rate was 14% (seven hematuria cases and one urethral tear case), and all were minor and spontaneously resolved without further treatment. In conclusion, removal of retrievable urethral stents using a retrieval hook wire was safe and effective despite some technical difficulties. It is a useful method for allowing temporary stent placement and solving various complications of stent use. (orig.)

  14. Removal of retrievable self-expandable urethral stents: experience in 58 stents

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Ji Hoon; Song, Ho-Young; Kim, Jin Hyoung; Ko, Heung-Kyu; Kim, Yong Jae; Woo, Chul-Woong; Kim, Tae-Hyung; Ko, Gi-Young; Yoon, Hyun-Ki; Sung, Kyu-Bo [Asan Medical Center, Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Seoul (Korea); Park, Hyungkeun [Asan Medical Center, Department of Urology, University of Ulsan College of Medicine, Seoul (Korea)

    2006-09-15

    The purpose of this study was to retrospectively evaluate the safety and efficacy of removing retrievable self-expandable urethral stents using a retrieval hook wire. Under fluoroscopic guidance, the removal of 58 polyurethane or PTFE (polytetrafluoroethylene)-covered stents was attempted in 33 patients using a retrieval hook wire. Indications for removal were elective removal (n=21), stent migration (n=19), formation of tissue hyperplasia around or inside of the stent (n=14), stent deformity (n=3), and severe pain (n=1). The mean time the stents remained in place was 64.8{+-}42.9 days (range, 1-177 days). Fifty-six (97%) of the 58 stents were successfully removed using the retrieval hook wire despite the following difficulties; hook wire disconnection (n=2), untied drawstrings (n=3), and polyurethane membrane disruption/separation (n=4). The removal procedure using a retrieval hook wire failed in two stents (3%) which had migrated into the urinary bladder. One of the two stents with migration into the urinary bladder was removed using a snare through the cystostomy route. The overall complication rate was 14% (seven hematuria cases and one urethral tear case), and all were minor and spontaneously resolved without further treatment. In conclusion, removal of retrievable urethral stents using a retrieval hook wire was safe and effective despite some technical difficulties. It is a useful method for allowing temporary stent placement and solving various complications of stent use. (orig.)

  15. Randomized controlled study of excimer laser atherectomy for treatment of femoropopliteal in-stent restenosis: initial results from the EXCITE ISR trial (EXCImer Laser Randomized Controlled Study for Treatment of FemoropopliTEal In-Stent Restenosis).

    Science.gov (United States)

    Dippel, Eric J; Makam, Prakash; Kovach, Richard; George, Jon C; Patlola, Raghotham; Metzger, D Christopher; Mena-Hurtado, Carlos; Beasley, Robert; Soukas, Peter; Colon-Hernandez, Pedro J; Stark, Matthew A; Walker, Craig

    2015-01-01

    The purpose of this study was to evaluate the safety and efficacy of excimer laser atherectomy (ELA) with adjunctive percutaneous transluminal angioplasty (PTA) versus PTA alone for treating patients with chronic peripheral artery disease with femoropopliteal bare nitinol in-stent restenosis (ISR). Femoropopliteal stenting has shown superiority to PTA for lifestyle-limiting claudication and critical limb ischemia, although treating post-stenting artery reobstruction, or ISR, remains challenging. The multicenter, prospective, randomized, controlled EXCITE ISR (EXCImer Laser Randomized Controlled Study for Treatment of FemoropopliTEal In-Stent Restenosis) trial was conducted across 40 U.S. centers. Patients with Rutherford Class 1 to 4 and lesions of target lesion length ≥4 cm, vessel diameter 5 to 7 mm were enrolled and randomly divided into ELA + PTA and PTA groups by a 2:1 ratio. The primary efficacy endpoint was target lesion revascularization (TLR) at 6-month follow up. The primary safety endpoint was major adverse event (death, amputation, or TLR) at 30 days post-procedure. Study enrollment was stopped at 250 patients due to early efficacy demonstrated at a prospectively-specified interim analysis. A total of 169 ELA + PTA subjects (62.7% male; mean age 68.5 ± 9.8 years) and 81 PTA patients (61.7% male; mean age 67.8 ± 10.3 years) were enrolled. Mean lesion length was 19.6 ± 12.0 cm versus 19.3 ± 11.9 cm, and 30.5% versus 36.8% of patients exhibited total occlusion. ELA + PTA subjects demonstrated superior procedural success (93.5% vs. 82.7%; p = 0.01) with significantly fewer procedural complications. ELA + PTA and PTA subject 6-month freedom from TLR was 73.5% versus 51.8% (p < 0.005), and 30-day major adverse event rates were 5.8% versus 20.5% (p < 0.001), respectively. ELA + PTA was associated with a 52% reduction in TLR (hazard ratio: 0.48; 95% confidence interval: 0.31 to 0.74). The EXCITE ISR trial is the first large, prospective, randomized study

  16. A Novel Self-Expandable, Radioactive Airway Stent Loaded with 125I Seeds: A Feasibility and Safety Study in Healthy Beagle Dog.

    Science.gov (United States)

    Wang, Yong; Guo, Jin-He; Zhu, Guang-Yu; Zhu, Hai-Dong; Chen, Li; Lu, Jian; Wang, Chao; Teng, Gao-Jun

    2017-07-01

    Airway stent placement is an effective treatment for the immediate palliation of malignant airway obstruction. However, restenosis caused by tumor ingrowth and/or overgrowth after stenting is common. The purpose of this study was to investigate the feasibility and safety of a novel self-expandable stent loaded with 125 I seeds in healthy beagle dog. Under fluoroscopic guidance, forty-eight self-expandable airway stents loaded with 125 I seeds were perorally placed in the main trachea of 48 healthy beagle dogs, who were randomly divided into four groups (Group A: 0.3 mCi; Group B: 0.6 mCi; Group C: 0.9 mCi; Control group: 0 mCi). The estimated radiation dose was calculated using the isotropic point source approximation. Radiological follow-up examinations and histopathological examinations of stented tracheal segments and their adjacent organs and tissues were performed at 2, 4, 8, and 16 weeks following the stenting. All stents were successfully deployed in the targeted tracheal segment in the beagle dogs without procedure-related complications. Tracheal stenosis became severe gradually in all the four groups, which was not associated with the radioactivity of 125 I seeds (p > 0.05). The tracheal injury scores increased along with the higher dose of radioactive seeds which reached peak at 8 weeks and then turned back slightly at 16 weeks. The adjacent tissue did not show pathohistological changes under microscope, while mild and reversible ultrastructure changes were showed under electronic microscope. This study demonstrates that it is feasible and safe to insert this novel self-expandable airway stent loaded with 125 I seeds in healthy beagle dog.

  17. Coronary Stent Artifact Reduction with an Edge-Enhancing Reconstruction Kernel - A Prospective Cross-Sectional Study with 256-Slice CT.

    Science.gov (United States)

    Tan, Stéphanie; Soulez, Gilles; Diez Martinez, Patricia; Larrivée, Sandra; Stevens, Louis-Mathieu; Goussard, Yves; Mansour, Samer; Chartrand-Lefebvre, Carl

    2016-01-01

    Metallic artifacts can result in an artificial thickening of the coronary stent wall which can significantly impair computed tomography (CT) imaging in patients with coronary stents. The objective of this study is to assess in vivo visualization of coronary stent wall and lumen with an edge-enhancing CT reconstruction kernel, as compared to a standard kernel. This is a prospective cross-sectional study involving the assessment of 71 coronary stents (24 patients), with blinded observers. After 256-slice CT angiography, image reconstruction was done with medium-smooth and edge-enhancing kernels. Stent wall thickness was measured with both orthogonal and circumference methods, averaging thickness from diameter and circumference measurements, respectively. Image quality was assessed quantitatively using objective parameters (noise, signal to noise (SNR) and contrast to noise (CNR) ratios), as well as visually using a 5-point Likert scale. Stent wall thickness was decreased with the edge-enhancing kernel in comparison to the standard kernel, either with the orthogonal (0.97 ± 0.02 versus 1.09 ± 0.03 mm, respectively; pkernel generated less overestimation from nominal thickness compared to the standard kernel, both with the orthogonal (0.89 ± 0.19 versus 1.00 ± 0.26 mm, respectively; pkernel was associated with lower SNR and CNR, as well as higher background noise (all p kernel. Stent visual scores were higher with the edge-enhancing kernel (pkernel generates thinner stent walls, less overestimation from nominal thickness, and better image quality scores than the standard kernel.

  18. A non-randomized study in consecutive patients with postcholecystectomy refractory biliary leaks who were managed endoscopically with the use of multiple plastic stents or fully covered self-expandable metal stents (with videos).

    Science.gov (United States)

    Canena, Jorge; Liberato, Manuel; Meireles, Liliane; Marques, Inês; Romão, Carlos; Coutinho, António Pereira; Neves, Beatriz Costa; Veiga, Pedro Mota

    2015-07-01

    Endoscopic management of postcholecystectomy biliary leaks is widely accepted as the treatment of choice. However, refractory biliary leaks after a combination of biliary sphincterotomy and the placement of a large-bore (10F) plastic stent can occur, and the optimal rescue endotherapy for this situation is unclear. To compare the clinical effectiveness of the use of a fully covered self-expandable metal stent (FCSEMS) with the placement of multiple plastic stents (MPS) for the treatment of postcholecystectomy refractory biliary leaks. Prospective study. Two tertiary-care referral academic centers and one general district hospital. Forty consecutive patients with refractory biliary leaks who underwent endoscopic management. Temporary placement of MPS (n = 20) or FCSEMSs (n = 20). Clinical outcomes of endotherapy as well as the technical success, adverse events, need for reinterventions, and prognostic factors for clinical success. Endotherapy was possible in all patients. After endotherapy, closure of the leak was accomplished in 13 patients (65%) who received MPS and in 20 patients (100%) who received FCSEMSs (P = .004). The Kaplan-Meier (log-rank) leak-free survival analysis showed a statistically significant difference between the 2 patient populations (χ(2) [1] = 8.30; P stents (P = .024), a plastic stent diameter <20F (P = .006), and a high-grade biliary leak (P = .015) were shown to be significant predictors of treatment failure with MPS. The 7 patients in whom placement of MPS failed were retreated with FCSEMSs, resulting in closure of the leaks in all cases. Non-randomized design. In our series, the results of the temporary placement of FCSEMSs for postcholecystectomy refractory biliary leaks were superior to those from the use of MPS. A randomized study is needed to confirm our results before further recommendations. Copyright © 2015 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

  19. Combined Arterial Infusion and Stent Implantation Compared with Metal Stent Alone in Treatment of Malignant Gastroduodenal Obstruction

    International Nuclear Information System (INIS)

    Wang Zhongmin; Chen Kemin; Gong Ju; Zheng Yunfeng; Wang Tianxiang

    2009-01-01

    Many patients with malignant gastroduodenal obstruction have an unresectable primary lesion and distant metastases, which may prompt palliative management to allow the patient to eat and to improve the quality of life. Intraluminal metallic stent implantation (MSI) under fluoroscopic guidance has been reported to be an effective option for symptomatic relief in these patients, with a good safety record. An alternative, dual interventional therapy (DIT), has been used during the last decade, in which prosthesis insertion is followed by intra-arterial chemotherapy via the tumor-feeding arteries. The aim of this study was to compare success rates, complication rates, and survival time between MSI and DIT in patients who presented with gastroduodenal obstruction from advanced upper gastrointestinal tract cancer. All consecutive patients with malignant gastroduodenal obstruction seen at our center between October 2002 and August 2007 were retrospectively studied. Patients were treated palliatively by either MSI or DIT by the patient's or the next of kin's decision. Outcomes included technical and clinical success, complication rates, and survival. Of the 164 patients with malignant gastric and duodenal outlet obstructions, 80 (49%) underwent stent insertion as the primary therapy, while the remaining 84 (51%) received DIT. Clinical characteristics were similar between the two groups. In the MSI cohort initial stent implantation was successful in 73 patients (91%), two stents were used in 5 patients, and delayed additional stent insertion for stent obstruction related to tumor overgrowth was required in 3 patients during follow-up. In the DIT cohort the technical success rate was 94%, 3 patients required two stents, and stent obstruction occurred in 2 patients after initial stent placement. Early postprocedural clinical success, indicated by average dysphagia score, improved significantly in both groups: MSI group, from 4.56 to 1.51 (P < 0.01); and DIT group, from 4

  20. Study comparing the double kissing (DK) crush with classical crush for the treatment of coronary bifurcation lesions: the DKCRUSH-1 Bifurcation Study with drug-eluting stents.

    Science.gov (United States)

    Chen, S L; Zhang, J J; Ye, F; Chen, Y D; Patel, T; Kawajiri, K; Lee, M; Kwan, T W; Mintz, G; Tan, H C

    2008-06-01

    Classical crush has a lower rate of final kissing balloon inflation (FKBI) immediately after percutaneous coronary intervention (PCI). The double kissing (DK) crush technique has the potential to increase the FKBI rate, and no prospective studies on the comparison of classical with DK crush techniques have been reported. Three hundred and eleven patients with true bifurcation lesions were randomly divided into classical (n = 156) and DK crush (n = 155) groups. Clinical and angiographic details at follow-up at 8 months were indexed. The primary end point was major adverse cardiac events (MACE) including myocardial infarction, cardiac death and target lesion revascularization (TLR) at 8 months. FKBI was 76% in the classical crush group and 100% in the DK group (P DK crush group. Cumulative 8 month MACE was 24.4% in the classical crush group and 11.4% in the DK crush group (P = 0.02). The TLR-free survival rate was 75.4% in the classical crush group and 89.5% in the DK crush group (P = 0.002). DK crush technique has the potential of increasing FKBI rate and reducing stent thrombosis, with a further reduction of TLR and cumulative MACE rate at 8 months.

  1. A comparison of the temporary placement of 3 different self-expanding stents for the treatment of refractory benign esophageal strictures: a prospective multicentre study

    Directory of Open Access Journals (Sweden)

    Canena Jorge Manuel

    2012-06-01

    Full Text Available Abstract Background Refractory benign esophageal strictures (RBESs have been treated with the temporary placement of different self-expanding stents with conflicting results. We compared the clinical effectiveness of 3 types of stents: self-expanding plastic stents (SEPSs, biodegradable stents, and fully covered self-expanding metal stents (FCSEMSs, for the treatment of RBES. Methods This study prospectively evaluated 3 groups of 30 consecutive patients with RBESs who underwent temporary placement of either SEPSs (12 weeks, n = 10, biodegradable stents (n = 10 or FCSEMSs (12 weeks, n = 10. Data were collected to analyze the technical success and clinical outcome of the stents as evaluated by recurrent dysphagia, complications and reinterventions. Results Stent implantation was technically successful in all patients. Migration occurred in 11 patients: 6 (60% in the SEPS group, 2 (20% in the biodegradable group and 3 (30% in the FCSEMS group (P = 0.16. A total of 8/30 patients (26.6% were dysphagia-free after the end of follow-up: 1 (10% in the SEPS group, 3 (30% in the biodegradable group and 4 (40% in the FCSEMS group (P = 0.27. More reinterventions were required in the SEPS group (n = 24 than in the biodegradable group (n = 13 or the FCSEMS group (n = 13 (P = 0.24. Multivariate analysis showed that stricture length was significantly associated with higher recurrence rates after temporary stent placement (HR = 1.37; 95% CI = 1.08-1.75; P = 0.011. Conclusions Temporary placement of a biodegradable stent or of a FCSEMS in patients with RBES may lead to long-term relief of dysphagia in 30 and 40% of patients, respectively. The use of SEPSs seems least preferable, as they are associated with frequent stent migration, more reinterventions and few cases of long-term improvement. Additionally, longer strictures were associated with a higher risk of recurrence.

  2. A Prospective, Multicenter Study of a Novel Mesh-Covered Carotid Stent: The CGuard CARENET Trial (Carotid Embolic Protection Using MicroNet).

    Science.gov (United States)

    Schofer, Joachim; Musiałek, Piotr; Bijuklic, Klaudija; Kolvenbach, Ralf; Trystula, Mariusz; Siudak, Zbigniew; Sievert, Horst

    2015-08-17

    This study sought to evaluate the feasibility of the CGuard Carotid Embolic Protective Stent system-a novel thin strut nitinol stent combined with a polyethylene terephthalate mesh covering designed to prevent embolic events from the target lesion in the treatment of carotid artery lesions in consecutive patients suitable for carotid artery stenting. The risk of cerebral embolization persists throughout the carotid artery stenting procedure and remains during the stent healing period. A total of 30 consecutive patients (age 71.6 ± 7.6 years, 63% male) meeting the conventional carotid artery stenting inclusion criteria were enrolled in 4 centers in Germany and Poland. The primary combined endpoint was the procedure success of the CGuard system and the number and volume of new lesions on the ipsilateral side assessed by diffusion-weighted magnetic resonance imaging at 48 h post-procedure and at 30 days. The secondary endpoint was 30-day major adverse cardiac or cerebrovascular events (death, stroke, or myocardial infarction). Protection devices were used in all procedures. Procedure success was 100%, with 0% procedural complications. The 30-day major adverse cardiac or cerebrovascular events rate was 0%. New ipsilateral ischemic lesions at 48 h occurred in 37.0% of patients and the average lesion volume was 0.039 ± 0.08 cm(3). The 30-day diffusion-weighted magnetic resonance imaging showed complete resolution of all but 1 periprocedural lesion and only 1 new minor (0.116 cm(3)) lesion in relation to the 48-h scan. The use of the CGuard system in patients undergoing carotid artery stenting is feasible. In addition, the benefit of using CGuard may extend throughout the stent healing period. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  3. Stent coverage and neointimal proliferation in bare metal stents postdilated with a Paclitaxel-eluting balloon versus everolimus-eluting stents: prospective randomized study using optical coherence tomography at 6-month follow-up.

    Science.gov (United States)

    Poerner, Tudor C; Otto, Sylvia; Gassdorf, Johannes; Nitsche, Kristina; Janiak, Florian; Scheller, Bruno; Goebel, Björn; Jung, Christian; Figulla, Hans R

    2014-12-01

    In this randomized trial, strut coverage and neointimal proliferation of a therapy of bare metal stents (BMSs) postdilated with the paclitaxel drug-eluting balloon (DEB) was compared with everolimus drug-eluting stents (DESs) at 6-month follow-up using optical coherence tomography. We hypothesized sufficient stent coverage at follow-up. A total of 105 lesions in 90 patients were treated with either XIENCE V DES (n=51) or BMS postdilated with the SeQuent Please DEB (n=54). At follow-up, comparable results on the primary optical coherence tomography end point (percentage uncovered struts 5.64±9.65% in BMS+DEB versus 4.93±9.29% in DES; P=0.366) were found. Thus, BMS+DEB achieved the prespecified noninferiority margin of 5% uncovered struts versus DES (difference between treatment means, 0.71%; one-sided upper 95% confidence interval, 4.14%; noninferiority P=0.04). Optical coherence tomography analysis showed significantly more global neointimal proliferation in the BMS+DEB group (15.7±7.8 versus 11.0±5.2 mm(3) proliferation volume/cm stent length; P=0.002). No significant focal in-stent stenosis analyzed with angiography (percentage diameter stenosis at follow-up, 22.8±11.9 versus 16.9±10.4; P=0.014) and optical coherence tomography (peak local area stenosis, 39.5±13.8% versus 36.8±15.6%; P=0.409) was found. Good stent strut coverage of >94% was found in both therapy groups. Despite greater suppression of global neointimal growth in DES, both DES and BMS+DEB effectively prevented clinically relevant focal restenosis at 6-month follow-up. http://www.clinicaltrials.gov. Unique identifier: NCT01056744. © 2014 American Heart Association, Inc.

  4. Dual-therapy stent technology for patients with coronary artery disease : A great catch?

    NARCIS (Netherlands)

    Kalkman, D.N.

    2018-01-01

    This thesis investigates the possible advantages of a new stent technology that aims to improve care for patients with coronary artery disease. The COMBO stent (OrbusNeich Medical BV, The Netherlands) contains a dual-therapy stent technology. The stent combines two techniques: a sirolimus-elution

  5. A Phase II study of external-beam radiotherapy and endovascular brachytherapy with PTA and stenting for femoropopliteal artery restenosis

    International Nuclear Information System (INIS)

    Narayan, Kailash; Denton, Michael; Das, Ram; Bernshaw, David; Rolfo, Aldo; Dyk, Sylvia van; Mirakian, Alex

    2006-01-01

    Purpose: To assess the safety and seek evidence of efficacy of combined external-beam radiotherapy (EBRT) and endovascular brachytherapy in the treatment of stenotic vascular lesions. Methods and Materials: Seventeen patients with high risk for restenosis of femoropopliteal arteries were enrolled in this study from February 2000 to August 2002. The external beam radiotherapy regimen consisted of 10 Gy in 5 fractions of 2 Gy, starting on Day 0. This was followed on Day 6 by angiography, stent placement, and intraluminal brachytherapy to a dose of 10 Gy at 1.2 mm from stent surface. The EBRT was continued from the same day to another 10 Gy in 2 Gy daily fractions for 5 days. Results: The follow up ranged from 33 months to 60 months. At the time of analysis 15 of 17 patients were alive with patent stents. Of these, 10 were symptom-free. Two patients died of unrelated causes. Conclusions: The combination of EBRT and endovascular brachytherapy provided adequate dose distribution without any geographical miss or 'candy wrapper' restenosis. No incidence of aneurysmal dilation of radiated vascular segment was observed. The treatment was feasible, well tolerated, and achieved 88% stenosis free survival

  6. The REMEDEE-OCT Study: An Evaluation of the Bioengineered COMBO Dual-Therapy CD34 Antibody-Covered Sirolimus-Eluting Coronary Stent Compared With a Cobalt-Chromium Everolimus-Eluting Stent in Patients With Acute Coronary Syndromes: Insights From Optical Coherence Tomography Imaging Analysis

    NARCIS (Netherlands)

    Jaguszewski, Milosz; Aloysius, Romila; Wang, Wei; Bezerra, Hiram G.; Hill, Jonathan; de Winter, Robbert J.; Karjalainen, Pasi P.; Verheye, Stefan; Wijns, William; Lüscher, Thomas F.; Joner, Michael; Costa, Marco; Landmesser, Ulf

    2017-01-01

    The aim of the present study was to evaluate vascular healing of the bioengineered COMBO Dual Therapy Stent compared with a cobalt-chromium (CoCr) everolimus-eluting stent (EES) as assessed by optical coherence tomography in patients with acute coronary syndromes. CD34+ cells promote endothelial

  7. Mechanical design of an intracranial stent for treating cerebral aneurysms.

    Science.gov (United States)

    Shobayashi, Yasuhiro; Tanoue, Tetsuya; Tateshima, Satoshi; Tanishita, Kazuo

    2010-11-01

    Endovascular treatment of cerebral aneurysms using stents has advanced markedly in recent years. Mechanically, a cerebrovascular stent must be very flexible longitudinally and have low radial stiffness. However, no study has examined the stress distribution and deformation of cerebrovascular stents using the finite element method (FEM) and experiments. Stents can have open- and closed-cell structures, and open-cell stents are used clinically in the cerebrovasculature because of their high flexibility. However, the open-cell structure confers a risk of in-stent stenosis due to protrusion of stent struts into the normal parent artery. Therefore, a flexible stent with a closed-cell structure is required. To design a clinically useful, highly flexible, closed-cell stent, one must examine the mechanical properties of the closed-cell structure. In this study, we investigated the relationship between mesh patterns and the mechanical properties of closed-cell stents. Several mesh patterns were designed and their characteristics were studied using numerical simulation. The results showed that the bending stiffness of a closed-cell stent depends on the geometric configuration of the stent cell. It decreases when the stent cell is stretched in the circumferential direction. Mechanical flexibility equal to an open-cell structure was obtained in a closed-cell structure by varying the geometric configuration of the stent cell. Copyright © 2010 IPEM. Published by Elsevier Ltd. All rights reserved.

  8. Dedicated bifurcation stents

    Directory of Open Access Journals (Sweden)

    Ajith Ananthakrishna Pillai

    2012-03-01

    Full Text Available Bifurcation percutaneous coronary intervention (PCI is still a difficult call for the interventionist despite advancements in the instrumentation, technical skill and the imaging modalities. With major cardiac events relate to the side-branch (SB compromise, the concept and practice of dedicated bifurcation stents seems exciting. Several designs of such dedicated stents are currently undergoing trials. This novel concept and pristine technology offers new hope notwithstanding the fact that we need to go a long way in widespread acceptance and practice of these gadgets. Some of these designs even though looks enterprising, the mere complex delivering technique and the demanding knowledge of the exact coronary anatomy makes their routine use challenging.

  9. Nitinol Esophageal Stents: New Designs and Clinical Indications

    International Nuclear Information System (INIS)

    Strecker, Ernst-Peter; Boos, Irene; Vetter, Sylvia; Strohm, Michael; Domschke, Sigurd

    1996-01-01

    Purpose: To evaluate the clinical use of covered and noncovered, knitted nitinol stents in patients presenting new stent indications. Methods: Self-expandable, knitted nitinol stents were implanted in four patients for treatment of dysphagia. In two patients who had malignant strictures and had esophago-respiratory fistulae and in one patient with an esophagocutaneous fistula, polytetrafluoroethylene (PTFE)-covered stents were implanted. One patient received a noncovered stent, but a retrograde approach through a percutaneous endoscopic gastrostomy (PEG) fistula had to be chosen for recanalization of an esophageal occlusion. Two patients received stents for treatment of benign strictures. Results: Recanalization of the stricture and stent implantation were performed under fluoroscopic control without any procedure-related morbidity or mortality. Dysphagia improved in all patients and the esophageal fistulae could be sealed off by covered stents. During a maximum follow-up of 18 months, there was no stent migration or esophageal perforation. Complications observed were stent stenosis due to food impaction (1/4) and benign stent stenosis (2/2). Most complications could be treated by the interventional radiologist. Conclusion: Self-expandable, covered Nitinol stents provide an option for the treatment of dysphagia combined with esophageal fistulae. In combination with interventional radiology techniques, even complex strictures are accessible. For benign strictures, the value of stent treatment has not yet been proven

  10. Risk Factors for Migration, Fracture, and Dislocation of Pancreatic Stents

    Directory of Open Access Journals (Sweden)

    Yoshiaki Kawaguchi

    2015-01-01

    Full Text Available Aim. To analyze the risk factors for pancreatic stent migration, dislocation, and fracture in chronic pancreatitis patients with pancreatic strictures. Materials and Methods. Endoscopic stent placements (total 386 times were performed in 99 chronic pancreatitis patients with pancreatic duct stenosis at our institution between April 2006 and June 2014. We retrospectively examined the frequency of stent migration, dislocation, and fracture and analyzed the patient factors and stent factors. We also investigated the retrieval methods for migrated and fractured stents and their success rates. Results. The frequencies of stent migration, dislocation, and fracture were 1.5% (5/396, 0.8% (3/396, and 1.2% (4/396, respectively. No significant differences in the rates of migration, dislocation, or fracture were noted on the patient factors (etiology, cases undergoing endoscopic pancreatic sphincterotomy, location of pancreatic duct stenosis, existence of pancreatic stone, and approach from the main or minor papilla and stent factors (duration of stent placement, numbers of stent placements, stent shape, diameter, and length. Stent retrieval was successful in all cases of migration. In cases of fractured stents, retrieval was successful in 2 of 4 cases. Conclusion. Stent migration, fracture, and dislocation are relatively rare, but possible complications. A good understanding of retrieval techniques is necessary.

  11. Predictive Factors of In-Stent Restenosis in Renal Artery Stenting: A Retrospective Analysis

    International Nuclear Information System (INIS)

    Vignali, Claudio; Bargellini, Irene; Lazzereschi, Michele; Cioni, Roberto; Petruzzi, Pasquale; Caramella, Davide; Pinto, Stefania; Napoli, Vinicio; Zampa, Virna; Bartolozzi, Carlo

    2005-01-01

    Purpose. To retrospectively evaluate the role of clinical and procedural factors in predicting in-stent restenosis in patients with renovascular disease treated by renal artery stenting. Methods. From 1995 to 2002, 147 patients underwent renal artery stenting for the treatment of significant ostial atherosclerotic stenosis. Patients underwent strict clinical and color-coded duplex ultrasound follow-up. Ninety-nine patients (111 stents), with over 6 months of continuous follow-up (mean 22±12 months, range 6-60 months), were selected and classified according to the presence (group A, 30 patients, 32 lesions) or absence (group B, 69 patients, 79 lesions) of significant in-stent restenosis. A statistical analysis was performed to identify possible preprocedural and procedural predictors of restenosis considering the following data: sex, age, smoking habit, diabetes mellitus, hypertension, serum creatinine, cholesterol and triglyceride levels, renal artery stenosis grade, and stent type, length and diameter. Results. Comparing group A and B patients (χ 2 test), a statistically significant relation was demonstrated between stent diameter and length and restenosis: the risk of in-stent restenosis decreased when the stent was ≥6 mm in diameter and between 15 and 20 mm in length. This finding was confirmed by multiple logistic regression analysis. Stent diameter and length were proved to be significantly related to in-stent restenosis also when evaluating only patients treated by Palmaz stent (71 stents). Conclusion. Although it is based on a retrospective analysis, the present study confirms the importance of correct stent selection in increasing long-term patency, using stents of at least 6 mm in diameter and with a length of approximately 15-20 mm

  12. Laparoscopic common bile duct exploration and antegrade biliary stenting: Leaving behind the Kehr tube

    Directory of Open Access Journals (Sweden)

    Darío Martínez-Baena

    2013-03-01

    Full Text Available Introduction: single-stage laparoscopic surgery of cholelithiasis and associated common bile duct stones (CL-CBDS has shown similar results when compared to laparoscopic cholecystectomy combined with ERCP. Classically, choledochorrhaphy has been protected by a T-tube drain to allow external bypass of bile flow. However, its removal is associated with a significant complication rate. Use of antegrade biliary stents avoids T-tube removal associated morbidity. The aim of this study is to compare the results of choledochorrhaphy plus T-tube drainage versus antegrade biliary stenting in our series of laparoscopic common bile duct explorations (LCBDE. Material and methods: between 2004 and 2011, 75 patients underwent a LCBDE. Choledochorrhaphy was performed following Kehr tube placements in 47 cases and transpapillary biliary stenting was conducted in the remaining 28 patients. Results: postoperative hospital stay was shorter in the stent group (5 ± 10.26 days than in the Kehr group (12 ± 10.6 days, with a statistically significant difference. There was a greater trend to grade B complications in the stent group (10.7 vs. 4.3 % and to grade C complications in the Kehr group (6.4 vs. 3.6 %. There were 3 cases of residual common bile duct stones in the Kehr group (6.4 % and none in the stent group. Conclusions: antegrade biliary stenting following laparoscopic common bile duct exploration for CL-CBDS is an effective and safe technique that prevents T-tube related morbidity.

  13. Computational hemodynamics of an implanted coronary stent based on three-dimensional cine angiography reconstruction.

    Science.gov (United States)

    Chen, Mounter C Y; Lu, Po-Chien; Chen, James S Y; Hwang, Ned H C

    2005-01-01

    Coronary stents are supportive wire meshes that keep narrow coronary arteries patent, reducing the risk of restenosis. Despite the common use of coronary stents, approximately 20-35% of them fail due to restenosis. Flow phenomena adjacent to the stent may contribute to restenosis. Three-dimensional computational fluid dynamics (CFD) and reconstruction based on biplane cine angiography were used to assess coronary geometry and volumetric blood flows. A patient-specific left anterior descending (LAD) artery was reconstructed from single-plane x-ray imaging. With corresponding electrocardiographic signals, images from the same time phase were selected from the angiograms for dynamic three-dimensional reconstruction. The resultant three-dimensional LAD artery at end-diastole was adopted for detailed analysis. Both the geometries and flow fields, based on a computational model from CAE software (ANSYS and CATIA) and full three-dimensional Navier-Stroke equations in the CFD-ACE+ software, respectively, changed dramatically after stent placement. Flow fields showed a complex three-dimensional spiral motion due to arterial tortuosity. The corresponding wall shear stresses, pressure gradient, and flow field all varied significantly after stent placement. Combined angiography and CFD techniques allow more detailed investigation of flow patterns in various segments. The implanted stent(s) may be quantitatively studied from the proposed hemodynamic modeling approach.

  14. Comparison of Self-Expanding Polyethylene Terephthalate and Metallic Stents Implanted in Porcine Iliac Arteries

    International Nuclear Information System (INIS)

    Wilczek, Krzysztof; Scheerder, Ivan de; Wang Kai; Verbeken, Eric; Piessens, Jan

    1996-01-01

    Purpose: Comparison of the biocompatibility of self-expanding polyethylene terephthalate (PET) stents with self-expanding metallic stents (Wallstents). Methods: Diameter- and length-matched PET stents and Wallstents were symmetrically implanted in the paired iliac arteries of 13 crossbred domestic swine. Stent deployment was studied angiographically and with intravascular ultrasound immediately after stent implantation. The angiographic stented lumen diameter was measured using quantitative vessel analysis before, immediately after stenting, and at 6-week follow-up. Cross-section histopathology and area morphometry were performed. Results: Immediately poststenting, intravascular ultrasound revealed proximal dislocation of 5 of the 13 PET stents, whereas all metal stents were firmly embedded at the implantation site. At 6-week follow-up, three of the remaining PET stents were totally or subtotally occluded by organized thrombus, whereas all metal stents were patent. Compared with immediately poststenting, the angiographic lumen diameter within the five remaining PET stents was reduced by 30%, and that of the metallic stents was virtually unaltered (p < 0.02). This observation was confirmed by postmortem morphometry, wherein the PET-stented vessel segments a diameter stenosis of 40% was measured vs only 9% in the metallic stents (p < 0.0001). Conclusion: PET-stent deployment is difficult to control due to the lack of radiopacity of this stent. PET stents seem to be more thrombogenic and lead to significantly more neointimal proliferation than metallic stents

  15. Comparative Study of Ureteral Stents Following Endoureterotomy in the Porcine Model: 3 vs 6 Weeks and 7F vs 14F

    International Nuclear Information System (INIS)

    Soria, Federico; Sanchez, Francisco M.; Sun, Fei; Ezquerra, Javier; Duran, Esther; Uson, Jesus

    2005-01-01

    The aim of the study was to determine the optimal stent size and stenting duration following retrograde endoureterotomy of experimental ureteral strictures. Twenty healthy Large White female pigs were randomly divided into four groups, depending on stent size (7F vs 14F) and stenting duration (3 weeks vs 6 weeks). Three additional pigs were used as the control group. The internal ureteral diameter was measured 2 cm below the lower pole of the right kidney. Histopathological changes of the urinary tract, ultrasonographic and fluoroscopic studies, urine culture, and serum urea and creatine levels were analyzed during the different phases of the study. The study was divided into three phases. Phase I included premodel documentation of the normal urinary tract and laparoscopic ureteral stricture creation. During the second phase 1 month later, the diagnosis and endourologic treatment of strictures were performed. Phase III began 4 weeks after stent removal; follow-up imaging studies and postmortem evaluation of all animals were performed. Ureteral strictures developed in all animals 4 weeks after model creation. Results from ureteral diameter measurements and pathological studies revealed no statistically significant intergroup differences. However, prevalence of urinary infection proved to be directly related to stent size (14F) and permanence (6 weeks). The chi square results suggest a statistically significant relationship between the urinary tract infection and recurrent strictures (α = 0.046). We recommend the use of 7F stents for a period of 3 weeks or less, as these are more easily positioned and result in the reduction of secondary side effects (lower infection rate, less intramural ureteral lesions). A significant relationship between urinary tract infection and stricture recurrence was found in this experimental study

  16. Palliative radiotherapy in addition to self-expanding metal stent for improving dysphagia and survival in advanced oesophageal cancer (ROCS: Radiotherapy after Oesophageal Cancer Stenting): study protocol for a randomized controlled trial.

    Science.gov (United States)

    Adamson, Douglas; Blazeby, Jane; Nelson, Annmarie; Hurt, Chris; Nixon, Lisette; Fitzgibbon, Jim; Crosby, Tom; Staffurth, John; Evans, Mim; Kelly, Noreen Hopewell; Cohen, David; Griffiths, Gareth; Byrne, Anthony

    2014-10-22

    The single most distressing symptom for patients with advanced esophageal cancer is dysphagia. Amongst the more effective treatments for relief of dysphagia is insertion of a self-expanding metal stent (SEMS). It is possible that the addition of a palliative dose of external beam radiotherapy may prolong the relief of dysphagia and provide additional survival benefit. The ROCS trial will assess the effect of adding palliative radiotherapy after esophageal stent insertion. The study is a randomized multicenter phase III trial, with an internal pilot phase, comparing stent alone versus stent plus palliative radiotherapy in patients with incurable esophageal cancer. Eligible participants are those with advanced esophageal cancer who are in need of stent insertion for primary management of dysphagia. Radiotherapy will be administered as 20 Gray (Gy) in five fractions over one week or 30 Gy in 10 fractions over two weeks, within four weeks of stent insertion. The internal pilot will assess rates and methods of recruitment; pre-agreed criteria will determine progression to the main trial. In total, 496 patients will be randomized in a 1:1 ratio with follow up until death. The primary outcome is time to progression of patient-reported dysphagia. Secondary outcomes include survival, toxicity, health resource utilization, and quality of life. An embedded qualitative study will explore the feasibility of patient recruitment by examining patients' motivations for involvement and their experiences of consent and recruitment, including reasons for not consenting. It will also explore patients' experiences of each trial arm. The ROCS study will be a challenging trial studying palliation in patients with a poor prognosis. The internal pilot design will optimize methods for recruitment and data collection to ensure that the main trial is completed on time. As a pragmatic trial, study strengths include collection of all follow-up data in the usual place of care, and a focus on

  17. Iliocaval Confluence Stenting for Chronic Venous Obstructions

    Energy Technology Data Exchange (ETDEWEB)

    Graaf, Rick de, E-mail: r.de.graaf@mumc.nl [Maastricht University Medical Centre (MUMC), Department of Radiology (Netherlands); Wolf, Mark de, E-mail: markthewolf@gmail.com [Maastricht University Medical Centre (MUMC), Department of Surgery (Netherlands); Sailer, Anna M., E-mail: anni.sailer@mumc.nl [Maastricht University Medical Centre (MUMC), Department of Radiology (Netherlands); Laanen, Jorinde van, E-mail: jorinde.van.laanen@mumc.nl; Wittens, Cees, E-mail: c.wittens@me.com [Maastricht University Medical Centre (MUMC), Department of Surgery (Netherlands); Jalaie, Houman, E-mail: hjalaie@ukaachen.de [University Hospital Aachen, Department of Surgery (Germany)

    2015-10-15

    PurposeDifferent techniques have been described for stenting of venous obstructions. We report our experience with two different confluence stenting techniques to treat chronic bi-iliocaval obstructions.Materials and MethodsBetween 11/2009 and 08/2014 we treated 40 patients for chronic total bi-iliocaval obstructions. Pre-operative magnetic resonance venography showed bilateral extensive post-thrombotic scarring in common and external iliac veins as well as obstruction of the inferior vena cava (IVC). Stenting of the IVC was performed with large self-expandable stents down to the level of the iliocaval confluence. To bridge the confluence, either self-expandable stents were placed inside the IVC stent (24 patients, SECS group) or high radial force balloon-expandable stents were placed at the same level (16 patients, BECS group). In both cases, bilateral iliac extensions were performed using nitinol stents.ResultsRecanalization was achieved for all patients. In 15 (38 %) patients, a hybrid procedure with endophlebectomy and arteriovenous fistula creation needed to be performed because of significant involvement of inflow vessels below the inguinal ligament. Mean follow-up was 443 ± 438 days (range 7–1683 days). For all patients, primary, assisted-primary, and secondary patency rate at 36 months were 70, 73, and 78 %, respectively. Twelve-month patency rates in the SECS group were 85, 85, and 95 % for primary, assisted-primary, and secondary patency. In the BECS group, primary patency was 100 % during a mean follow-up period of 134 ± 118 (range 29–337) days.ConclusionStenting of chronic bi-iliocaval obstruction shows relatively high patency rates at medium follow-up. Short-term patency seems to favor confluence stenting with balloon-expandable stents.

  18. Stenting of major airway constriction

    International Nuclear Information System (INIS)

    Wu Xiaomei

    2002-01-01

    Objective: To investigate the correlated issues in the stenting treatment of major airway constriction. Methods: Nineteen cases of major airway stenting procedure were studied retrospectively. The clinical choice of stents of different advantages or deficiencies were discussed. The importance of intravenous anesthesia supporting, life-parameters monitoring during the procedures and the prevention of complications were analysed. Results: Under intravenous and local anesthesia, 19 Wallstents had been successively placed and relieved 19 cases of major airway constrictions due to malignant or benign diseases (15 of tumors, 3 of tuberculosis, 1 of tracheomalacia). Intravenous anesthesia and life-parameters monitoring had made the procedures more safe and precise. Conclusions: Major airway stenting is an reliable method for relieving tracheobronchial stenosis; and intravenous anesthesia supporting and life-parameters monitoring guarantee the satisfactions of procedures

  19. Forgotten Ureteral Stents: An Avoidable Morbidity

    International Nuclear Information System (INIS)

    Murtaza, B.; Alvi, S.

    2016-01-01

    Objective: To assess the clinical presentation of forgotten ureteral stents and highlight the etiological factors resulting in the retention of these stents. Study Design: Observational study. Place and Duration of Study: Department of Urology, Armed Forces Institute of Urology, Rawalpindi, from January 2010 to Jun 2011. Methodology: Thirty-eight patients, with forgotten ureteral stents, retained for more than 6 months duration, were enrolled. A detailed evaluation was performed, along with the questions regarding the patients' opinion about the ureteral stents. They were specially asked whether they knew about the stents or were they formally informed regarding the stents. Subsequently, the patients were managed according to their clinical condition. Results: The male to female ratio was 2.1:1 aged 23 - 69 years, mean being 40.24 ± 12.59 years. The time of presentation after the ureteral stenting was 7 - 180 months (mean = 28.89 ± 33.435 years). Seven patients (18.4 percentage) reported with chronic kidney disease, including ESRD in two cases. Recurrent UTI was seen in 28 cases (73.6 percentage), calculus formed over the stents in 20 cases (52.6 percentage), and stent fragmented in 5 patients (13.1 percentage). Majority of patients, (n = 23, 60.5 percentage), were not even aware of the placement of these stents while 8 (21.0 percentage) knew but were reluctant about its removal. In 3 cases (7.8 percentage), the relatives knew about the stent but never informed the patients. The stent had been removed in 2 cases (5.2 percentage), but the other broken fragment was missed. One case (2.6 percentage) each had a misconception about the permanent placement of the stents like cardiac stents and regarding degradation of the stents in situ. Conclusion: Forgotten ureteral stents produce clinical features ranging from recurrent UTI to ESRD. This preventable urological complication is primarily due to the unawareness or ignorance of the patients and their relatives

  20. Experimental study of an endothelial progenitor cell coated stent in transjugular intrahepatic portosystemic shunt

    International Nuclear Information System (INIS)

    Shi Hongjian; Teng Gaojun; Cao Aihong; Chen Jun; Deng Gang

    2009-01-01

    Objective: To evaluate the efficacy of a self-expandable metal stent coated with autologous endothelial progenitor cells (EPCs) for prevention of restenosis in transjugular intrahepatic portosystemic shunt (TIPS) in a swine model. Methods: EPCs were coated on the metal stents using fibrin gel before TIPS procedure. TIPS was performed in 15 young adult pigs, using an autologous EPC-seeded stent (treatment group, n=9) or a conventional bare metal stent (control group, n=6). All pigs were sacrificed at 2 weeks after TIPS procedure. Portography was performed immediately before the euthanasia. Gross and microscopic pathological exams and immunohistochemical exams of the TIPS track specimens were performed. Fisher test and t test were used to analyse the data. Results: TIPS was performed successfully in all the 15 swine. On day 14 of follow-up, direct portography and necropsy demonstrated that 5 shunts remained patent, 2 shunts stenosed, and the remaining 2 shunts occluded in the treatment group (n=9); while 5 shunts were occluded and one shunt was stenotic in the control group (n=6). The patency rate was 56% vs 0 (P=0.03) between the two groups. Histological analyses showed a greater pseudo-intimal hyperplasia in the TIPS track of the control group than that of the treatment group (pseudointimal thickness at hepatic vein, hepatic parenchyma and portal vein site was (1.2±0.4), (1.3±0.5), (1.5±0.4) mm vs (1.0±0.6), (0.9±0.5), (1.0±0.4) mm respectively (P<0.05). Conclusion: The EPC-coated metal stent is feasibly constructed in vitro and improves the patency in TIPS in a porcine model. (authors)

  1. [Transjugular intrahepatic portosystemic shunting with covered stents in children: a preliminary study of safety and patency].

    Science.gov (United States)

    Zurera, L J; Espejo, J J; Canis, M; Bueno, A; Vicente, J; Gilbert, J J

    2014-01-01

    To retrospectively analyze the safety and efficacy of transjugular intrahepatic portosystemic shunting (TIPS) using covered stents in children. We present 6 children (mean age, 10.6 years; mean weight, 33.5kg) who underwent TIPS with 8mm diameter Viatorr(®) covered stents for acute (n=4) or recurrent (n=2) upper digestive bleeding that could not be controlled by endoscopic measures. Five of the children had cirrhosis and the other had portal vein thrombosis with cavernous transformation. We analyzed the relapse of upper digestive bleeding, the complications that appeared, and the patency of the TIPS shunt on sequential Doppler ultrasonography or until transplantation. A single stent was implanted in a single session in each child; none of the children died. The mean transhepatic gradient decreased from 16mmHg (range: 12-21mmHg) before the procedure to 9mmHg (range: 1-15mmHg) after TIPS. One patient developed mild encephalopathy, and the girl who had portal vein thrombosis with cavernous transformation developed an acute occlusion of the TIPS that resolved after the implantation of a coaxial stent. Three children received transplants (7, 9, and 10 months after the procedure, respectively), and the patency of the TIPS was confirmed at transplantation. In the three remaining children, patency was confirmed with Doppler ultrasonography 1, 3, and 5 months after implantation. None of the children had new episodes of upper digestive bleeding during follow-up after implantation (mean: 8.1 months). Our results indicate that TIPS with 8mm diameter Viatorr(®) covered stents can be safe and efficacious for the treatment of upper digestive bleeding due to gastroesophageal varices in cirrhotic children; our findings need to be corroborated in larger series. Copyright © 2011 SERAM. Published by Elsevier Espana. All rights reserved.

  2. Magnetic resonance evaluation of luminal patency after polylactide stent implantation: an experimental study in a rabbit aorta model

    International Nuclear Information System (INIS)

    Hietala, Eeva-Maija; Salminen, Ulla-Stina; Harjula, Ari L.J.; Maasilta, Paula; Staahls, Anders; Vaelimaa, Tero; Kivisaari, Leena

    2003-01-01

    Intravascular metallic stents cause magnetic field distortions, disturbing luminal detection. Our aim was to evaluate the effect of polylactic acid (PLA) stents on magnetic resonance angiography (MRA). Biodegradable double spiral helical PLA stents (n=12) or stainless steel (SS) (n=6) stents were implanted into the infrarenal aortas of New Zealand White rabbits. All SS- and 6 PLA-stented animals as well as 6 non-operated control rabbits were imaged with gadolinium-enhanced MRA (1.5 T), and infrarenal aortic diameters (proximal, distal, and narrowest), together with the stent artifact, were measured. Six of the PLA-stented rabbits were followed up, and MRA was assessed at 2, 6, 9, and 12 months after the stent implantation. Image artifacts caused by the SS stents were visualized in all cases. The PLA stents caused no magnetic field distortion, allowing imaging of the underlying vessel including the vessel lumen. In the follow-up group of 6 rabbits with a PLA stent, 5 of 6 were patent at the end of the follow-up of 12 months. These stents allowed luminal detection at all time points, with no significant differences in aortic measurements emerging during the whole follow-up period. When immediately postoperatively scanned SS and PLA rabbits were compared with controls, no differences were observable in proximal diameters. Instead, the percentage of distal luminal loss was greater in the PLA-stented rabbits, as compared with SS stents (p<0.01). The PLA stenting in small vessels allows evaluation of luminal patency with MRA both immediately after implantation and during follow-up. (orig.)

  3. Rationale and design of the East-West late lumen loss study: Comparison of late lumen loss between Eastern and Western drug-eluting stent study cohorts.

    Science.gov (United States)

    Harrison, Robert W; Radhakrishnan, Vaishnavi; Lam, Peter S; Allocco, Dominic J; Brar, Sandeep; Fahy, Martin; Fisher, Rebecca; Ikeno, Fumiaki; Généreux, Philippe; Kimura, Takeshi; Liu, Minglei; Lye, Weng Kit; Mintz, Gary S; Nagai, Hirofumi; Suzuki, Yuka; White, Roseann; Allen, John C; Krucoff, Mitchell W

    2016-12-01

    The contemporary evaluation of novel drug-eluting stents (DES) includes mechanistic observations that characterize postdeployment stent behavior. Quantification of late lumen loss due to neointimal hyperplasia 8-13 months after stent implantation, via quantitative coronary angiography (QCA), constitutes such an observation and is required by most regulatory authorities. Late lumen loss, as determined by QCA, has been validated as a surrogate for clinical endpoints such as target vessel revascularization. The mechanistic response to DES has not been directly compared across predominantly Asian or Western populations, whereas understanding their comparability across geographic populations could enhance global DES evaluation. The East-West late lumen loss study is designed to demonstrate whether the residual differences in late lumen loss, as assessed by QCA, is different between Eastern and Western DES recipients from studies with protocol angiography at 8-13 months of follow-up. Data from independent core laboratories that have characterized angiographic late lumen loss in DES clinical trials with protocol follow-up angiography will be compiled and dichotomized into Eastern and Western populations. A prospectively developed propensity score model incorporating clinical and anatomic variables affecting late lumen loss will be used to adjust comparisons of QCA measurements. Documentation of whether there are clinically meaningful differences in mechanistic response to DES implantation across genetically unique geographies could facilitate both the quality and efficiency of global device evaluation requiring invasive follow-up for novel stent designs. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Temporary urethral covered stent - third year of experience

    International Nuclear Information System (INIS)

    Stojanovis, V.; Maksimovis, H.; Markovis, B.; Markovis, Z.

    2006-01-01

    Full text: In October 2003, a new generation of urethral stents ALLIUM, produced in Israel, were used at the Department of Interventional Radiology, CCS, in 18 patients with chronic stricture of bulbar urethra. The indications for insertion were determined according to well-known and recognized therapeutical protocols. The stent is made of nitinol wire with polyurethane cover. It is inserted under local anesthesia by a special self-expandable system that may be fixed or flexible. The stents we used were 3-6 cm long and 28 Fr wide. Radioscopic-assisted insertion was performed over formerly placed metal guide. Prior to insertion, balloon-catheter dilatation of stricture matching the stent width was carried out. Pre-insertion urethrotomy was performed in one case. The insertion technique is simple, presupposing the knowledge of older generations of techniques of urethral dilatation and insertion of self-expandable stents. The follow-up of results was done according to a priori established protocol including the following: UCG, uroflowmetry and interview with patients. Due to stent migration, the 'stent over stent' technique was applied in one case, while reposition by balloon-catheter outward traction was performed in two cases of caudal migration. No irritative discomforts were reported in the first 4 months after stent dwelling. Uroflowmetric controls verified at least four times better results than before the insertion. Given it is the question of covered stent, there is no possibility of proliferative secondary lumen obstruction. On account of soft structure and conic shape of posterior part of stent, no lesions of the external urethral sphincter were manifested. The stent is simply withdrawn after 6 months by outward traction using the forceps at the time when the stent construction turns into soft and straight wire. The first clinical experiences are very favorable and ALLIUM stent may be expected to be the stent of choice for chronic bulbar strictures

  5. Radiotracer techniques in hydrological studies

    International Nuclear Information System (INIS)

    Oladipo, M.O.A.; Funtua, I.I.

    2000-07-01

    The use of radioactive tracers particularly short-lived radioisotopes frequently offers advantages over conventional methods of analyses. Applications of nuclear techniques in the field of hydrology constitute important and sometimes unique tools for obtaining critical information needed for water resources management. Essentially, radiotracer techniques offer a safe, cost effective and powerful tool in the assessment, management and protection of water resources. The Centre for Energy Research and Training, Ahmadu Bello University, Zaria of late has been offering consultancy services to some industries in the area of radiotracer technique. The first nuclear reactor in Nigeria, the MNSR, is expected to be commissioned in the Centre very soon. Many short-lived radioisotopes such as Cu-64, Ga-72, Br-82, Hg-197 etc which are very important in hydrological studies can be produced by the MNSR facility. This article reports on the basic principles of the technique and its roles in hydrology

  6. Chemico-physical characterisation and in vivo biocompatibility assessment of DLC-coated coronary stents.

    Science.gov (United States)

    Castellino, Micaela; Stolojan, Vlad; Virga, Alessandro; Rovere, Massimo; Cabiale, Karine; Galloni, Marco R; Tagliaferro, Alberto

    2013-01-01

    The vast majority of stent thrombosis occurs in the acute and sub-acute phases and is more common in patients with acute coronary syndromes, due to the thrombotic milieu where stent struts are positioned. Stent thrombosis is likely due to incomplete tissue coverage of metallic stents as the contact between metallic stents and blood elements may lead to platelet adhesion and trigger vessel thrombosis. If a stent is covered after 7 days, the risk that it will be found uncovered at later stages is very low (DLC) coatings, deposited by physical vapour deposition, promote rapid endothelisation of coronary stent devices, with very low platelets activation, reducing thrombotic clots. We relate these behaviours to the surface and bulk material properties of the DLC films, subjected to a comprehensive chemico-physical characterisation using several techniques (X-ray photoelectron spectroscopy, atomic force microscopy, field-emission scanning electron microscope, transmission electron microscopy combined with electron energy loss spectroscopy, Raman and dispersive X-ray spectroscopy). In vivo studies, conducted on 24 pigs, have shown complete endothelisation after 7 days, with no fibrin mesh and with only rare monocytes scattered on the endothelial layer while 30 and 180 days tests have shown reduced inflammatory activation and a complete stabilisation of the vessel healing, with a minimal neointimal proliferation. The integral and permanent DLC film coating improves haemo- and bio-compatibility and leads to an excellent early vessel healing of the stent whilst the extremely thin strut thickness reduces the amount of late neointima and consequently the risk of late restenosis. These data should translate into a reduced acute and sub-acute stent thrombosis.

  7. Computational Fluid Dynamics: Hemodynamic Changes in Abdominal Aortic Aneurysm After Stent-Graft Implantation

    International Nuclear Information System (INIS)

    Frauenfelder, Thomas; Lotfey, Mourad; Boehm, Thomas; Wildermuth, Simon

    2006-01-01

    The aim of this study was to demonstrate quantitatively and qualitatively the hemodynamic changes in abdominal aortic aneurysms (AAA) after stent-graft placement based on multidetector CT angiography (MDCT-A) datasets using the possibilities of computational fluid dynamics (CFD). Eleven patients with AAA and one patient with left-side common iliac aneurysm undergoing MDCT-A before and after stent-graft implantation were included. Based on the CT datasets, three-dimensional grid-based models of AAA were built. The minimal size of tetrahedrons was determined for grid-independence simulation. The CFD program was validated by comparing the calculated flow with an experimentally generated flow in an identical, anatomically correct silicon model of an AAA. Based on the results, pulsatile flow was simulated. A laminar, incompressible flow-based inlet condition, zero traction-force outlet boundary, and a no-slip wall boundary condition was applied. The measured flow volume and visualized flow pattern, wall pressure, and wall shear stress before and after stent-graft implantation were compared. The experimentally and numerically generated streamlines are highly congruent. After stenting, the simulation shows a reduction of wall pressure and wall shear stress and a more equal flow through both external iliac arteries after stenting. The postimplantation flow pattern is characterized by a reduction of turbulences. New areas of high pressure and shear stress appear at the stent bifurcation and docking area. CFD is a versatile and noninvasive tool to demonstrate changes of flow rate and flow pattern caused by stent-graft implantation. The desired effect and possible complications of a stent-graft implantation can be visualized. CFD is a highly promising technique and improves our understanding of the local structural and fluid dynamic conditions for abdominal aortic stent placement

  8. Creation of individual ideally shaped stents using multi-slice CT: in vitro results from the semi-automatic virtual stent (SAVS) designer

    International Nuclear Information System (INIS)

    Hyodoh, Hideki; Katagiri, Yoshimi; Hyodoh, Kazusa; Akiba, Hidenari; Hareyama, Masato; Sakai, Toyohiko

    2005-01-01

    To plan stent-grafting for thoracic aortic aneurysm with complicated morphology, we created a virtual stent-grafting program [Semi Automatic Virtual Stent (SAVS) designer] using three-dimensional CT data. The usefulness of the SAVS designer was evaluated by measurement of transformed anatomical and straight stents. Curved model images (source, multi-planer reconstruction and volume rendering) were created, and a hollow virtual stent was produced by the SAVS designer. A straight Nitinol stent was transformed to match the curved configuration of the virtual stent. The accuracy of the anatomical stent was evaluated by experimental strain phantom studies in comparison with the straight stent. Mean separation length was 0 mm in the anatomical stent [22 mm outer diameter (OD)] and 5 mm in the straight stent (22 mm OD). The straight stent strain voltage was four times that of the anatomical stent at the stent end. The anatomical stent is useful because it fits the curved structure of the aorta and reduces the strain force compared to the straight stent. The SAVS designer can help to design and produce the anatomical stent. (orig.)

  9. Self-Expandable Metal Stents and Trans-stent Light Delivery: Are Metal Stents and Photodynamic Therapy Compatible?

    Science.gov (United States)

    Wang, Luo-Wei; Li, Li-Bo; Li, Zhao-Shen; Chen, Yang K; Hetzel, Fred W.; Huang, Zheng

    2008-01-01

    Background and Objectives: Obstructive non-small cell lung cancer and obstructive esophageal cancer are US FDA approved indications of photodynamic therapy (PDT). The usefulness of PDT for the treatment of cholangiocarcinoma is currently under clinical investigation. Endoscopic stenting for lumen restoration is a common palliative intervention for those indications. It is important to assess whether self-expandable metal stents are compatible with trans-stent PDT light delivery. Study Design/Materials and Methods: Direct effects of various components of metal biliary (n = 2), esophageal (n = 2), and bronchial (n = 1) stents on PDT light transmittance and distribution were examined using a point or linear light source (630 or 652 nm diode laser). Resected pig biliary duct and esophageal wall tissues were used to examine the feasibility of PDT light delivery through the fully expanded metal stents. Results: While using a point light source, the metal components (thread and joint) of the stent could cause a significant shadow effect. The liner material (polytetrafluoroethylene or polyurethane) could cause various degrees of light absorption. When the stent was covered with a thin layer of biliary duct and esophageal tissues containing all wall layers, the shadow effect could be mitigated due to tissue scattering. Conclusions: This study clearly demonstrates that it is feasible to combine stenting and PDT for the treatment of luminal lesions. PDT light dose should be adjusted to counteract the reduction of light transmittance caused by the metal and liner materials of stent. PMID:18951422

  10. Acute stent recoil and optimal balloon inflation strategy: an experimental study using real-time optical coherence tomography.

    Science.gov (United States)

    Kitahara, Hideki; Waseda, Katsuhisa; Yamada, Ryotaro; Otagiri, Kyuhachi; Tanaka, Shigemitsu; Kobayashi, Yuhei; Okada, Kozo; Kume, Teruyoshi; Nakagawa, Kaori; Teramoto, Tomohiko; Ikeno, Fumiaki; Yock, Paul G; Fitzgerald, Peter J; Honda, Yasuhiro

    2016-06-12

    Our aim was to evaluate stent expansion and acute recoil at deployment and post-dilatation, and the impact of post-dilatation strategies on final stent dimensions. Optical coherence tomography (OCT) was performed on eight bare metal platforms of drug-eluting stents (3.0 mm diameter, n=6 for each) during and after balloon inflation in a silicone mock vessel. After nominal-pressure deployment, a single long (30 sec) vs. multiple short (10 sec x3) post-dilatations were performed using a non-compliant balloon (3.25 mm, 20 atm). Stent areas during deployment with original delivery systems were smaller in stainless steel stents than in cobalt-chromium and platinum-chromium stents (pstrategies showed a significant impact on final stent expansion.

  11. Hemodynamic comparison of stent configurations used for aortoiliac occlusive disease

    NARCIS (Netherlands)

    Groot Jebbink, Erik; Mathai, Varghese; Boersen, Johannes Thomas; Sun, Chao; Slump, Cornelis H.; Goverde, Peter C.J.M.; Versluis, Michel; Reijnen, Michel M.P.J.

    Background Endovascular treatment of aortoiliac occlusive disease entails the use of multiple stents to reconstruct the aortic bifurcation. Different configurations have been applied and geometric variations exist, as quantified in previous work. Other studies concluded that specific stent geometry

  12. Long-term safety and outcome of a temporary self-expanding metallic stent for achalasia: a prospective study with a 13-year single-center experience

    International Nuclear Information System (INIS)

    Zhao, Jun-Gong; Li, Yong-Dong; Li, Ming-Hua; Shang, Ke-Zhong; Cheng, Ying-Sheng; Chen, Ni-Wei; Chen, Wei-Xiong

    2009-01-01

    To prospectively evaluate the long-term clinical safety and efficacy of a newly designed self-expanding metallic stent (SEMS) in the treatment of patients with achalasia. Seventy-five patients with achalasia were treated with a temporary SEMS with a 30-mm diameter. The SEMSs were placed under fluoroscopic guidance and removed by gastroscopy 4-5 days after stent placement. Follow-up data focused on dysphagia score, technique and clinical success, clinical remissions and failures, and complications and was performed at 6 months, 1 year, and within 3 to 5 years, 5 to 8 years, 8 to 10 years, and >10 years postoperatively. Stent placement was technically successful in all patients. Complications included stent migration (n=4, 5.33%), chest pain (n=28, 38.7%), reflux (n=15, 20%), and bleeding (n=9, 12%). No perforation or 30-day mortality occurred. Clinical success was achieved in all patients 1 month after stent removal. The overall remission rates at 6 months, 1, 1-3, 3-5, 5-8, 8-10, and >10 year follow-up periods were 100%, 96%, 93.9%, 90.9%, 100%, 100%, and 83.3%, respectively. Stent treatment failed in six patients, and the overall remission rate in our series was 92%. The median and mean primary patencies were 2.8 ± 0.28 years (95% CI: 2.25-3.35) and 4.28 ± 0.40 years (95% CI: 3.51-5.05), respectively. The use of temporary SEMSs with 30-mm diameter proved to be a safe and effective approach for managing achalasia with a long-term satisfactory clinical remission rate. (orig.)

  13. Long-term safety and outcome of a temporary self-expanding metallic stent for achalasia: a prospective study with a 13-year single-center experience

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Jun-Gong; Li, Yong-Dong; Li, Ming-Hua; Shang, Ke-Zhong [Shanghai Tong Ji University, Department of Radiology, Tenth Affiliated People' s Hospital, Shanghai (China); Cheng, Ying-Sheng [Shanghai Tong Ji University, Department of Radiology, Tenth Affiliated People' s Hospital, Shanghai (China); Shanghai Jiao Tong University, Department of Radiology, Sixth Affiliated People' s Hospital, Shanghai (China); Chen, Ni-Wei; Chen, Wei-Xiong [Shanghai Jiao Tong University, Department of Gastroenterology, Sixth Affiliated People' s Hospital, Shanghai (China)

    2009-08-15

    To prospectively evaluate the long-term clinical safety and efficacy of a newly designed self-expanding metallic stent (SEMS) in the treatment of patients with achalasia. Seventy-five patients with achalasia were treated with a temporary SEMS with a 30-mm diameter. The SEMSs were placed under fluoroscopic guidance and removed by gastroscopy 4-5 days after stent placement. Follow-up data focused on dysphagia score, technique and clinical success, clinical remissions and failures, and complications and was performed at 6 months, 1 year, and within 3 to 5 years, 5 to 8 years, 8 to 10 years, and >10 years postoperatively. Stent placement was technically successful in all patients. Complications included stent migration (n=4, 5.33%), chest pain (n=28, 38.7%), reflux (n=15, 20%), and bleeding (n=9, 12%). No perforation or 30-day mortality occurred. Clinical success was achieved in all patients 1 month after stent removal. The overall remission rates at 6 months, 1, 1-3, 3-5, 5-8, 8-10, and >10 year follow-up periods were 100%, 96%, 93.9%, 90.9%, 100%, 100%, and 83.3%, respectively. Stent treatment failed in six patients, and the overall remission rate in our series was 92%. The median and mean primary patencies were 2.8 {+-} 0.28 years (95% CI: 2.25-3.35) and 4.28 {+-} 0.40 years (95% CI: 3.51-5.05), respectively. The use of temporary SEMSs with 30-mm diameter proved to be a safe and effective approach for managing achalasia with a long-term satisfactory clinical remission rate. (orig.)

  14. Management of JJ stent-related symptoms.

    Science.gov (United States)

    Papatsoris, Athanasios; Dellis, Athanasios; Daglas, George; Sanguedolce, Francesco

    2014-01-01

    Ureteric JJ stents are inserted in numerous pa- tients as a routine procedure. Nevertheless, the ideal JJ stent that does not cause any lower urinary tract symptoms has not been developed yet. Even special validated ques- tionnaires have been used for the assessment of JJ stent-related symtoms. For the management of such symtoms usually alpha-blockers are admin- istered. Also, studies have examined the efficacy and safety of anticholinergics and calcium channel blo- ckers. In this article we review the literature upon the management of JJ stent-related symptoms.

  15. High-dose external beam irradiation inhibits neointima formation in stented pig coronary arteries

    International Nuclear Information System (INIS)

    Verheye, Stefan; Coussement, Patrick K.; Salame, Mahomed Y.; Fallahi, Payam; Cui Jianhua; Chronos, Nicolas A.F.; King, Spencer B.; Crocker, Ian R.; Robinson, Keith A.

    2001-01-01

    Purpose: To evaluate high-dose external beam irradiation (EBRT) in a pig coronary stent preparation because low and intermediate-dose EBRT failed to show inhibition of neointima formation in stented animal models. Methods and Materials: Thirty-five stents were implanted in the coronary arteries of 17 pigs. Seven pigs were exposed to a single dose of 21 Gy EBRT immediately after stenting. Ten stented, nonirradiated pigs served as controls. After 4 weeks, the study arteries and myocardium were examined by light and scanning electron microscopy. Results: Compared with controls, 21 Gy EBRT resulted in a larger lumen area (7.57±1.67 mm 2 vs. 4.00±1.63 mm 2 , p 2 vs. 3.36±2.26 mm 2 , p<0.001) and a smaller maximal intimal thickness (0.16±0.09 mm vs. 0.68±0.31 mm, p<0.001). Unresorbed intramural hemorrhages and adherent mural thrombi were present in the irradiated vessels, which also showed incomplete re-endothelialization. The irradiated hearts demonstrated diffuse interstitial and perivascular inflammation and fibrosis. Conclusions: EBRT at 21 Gy to the entire heart significantly inhibited neointima formation in stented pig coronary arteries but also resulted in incomplete re-endothelialization, myocardial inflammation, and fibrosis. Improvements in localization and delivery techniques are required to allow clinical implementation of this technique

  16. Optimal Scanning Protocols for Dual-Energy CT Angiography in Peripheral Arterial Stents: An in Vitro Phantom Study

    Directory of Open Access Journals (Sweden)

    Abdulrahman Almutairi

    2015-05-01

    Full Text Available Objective: To identify the optimal dual-energy computed tomography (DECT scanning protocol for peripheral arterial stents while achieving a low radiation dose, while still maintaining diagnostic image quality, as determined by an in vitro phantom study. Methods: Dual-energy scans in monochromatic spectral imaging mode were performed on a peripheral arterial phantom with use of three gemstone spectral imaging (GSI protocols, three pitch values, and four kiloelectron volts (keV ranges. A total of 15 stents of different sizes, materials, and designs were deployed in the phantom. Image noise, the signal-to-noise ratio (SNR, different levels of adaptive statistical iterative reconstruction (ASIR, and the four levels of monochromatic energy for DECT imaging of peripheral arterial stents were measured and compared to determine the optimal protocols. Results: A total of 36 scans with 180 datasets were reconstructed from a combination of different protocols. There was a significant reduction of image noise with a higher SNR from monochromatic energy images between 65 and 70 keV in all investigated preset GSI protocols (p < 0.05. In addition, significant effects were found from the main effect analysis for these factors: GSI, pitch, and keV (p = 0.001. In contrast, there was significant interaction on the unstented area between GSI and ASIR (p = 0.015 and a very high significant difference between keV and ASIR (p < 0.001. A radiation dose reduction of 50% was achieved. Conclusions: The optimal scanning protocol and energy level in the phantom study were GSI-48, pitch value 0.984, and 65 keV, which resulted in lower image noise and a lower radiation dose, but with acceptable diagnostic images.

  17. Effects of 32P radioactive stents on in-stent restenosis in a double stent injury model of the porcine coronary arteries

    International Nuclear Information System (INIS)

    Kim, Han-Soo; Chan, Rosanna C.; Kollum, Marc; Au, Arthur; Tio, Fermin O.; Yazdi, Hamid A.; Ajani, Andrew E.; Waksman, Ron

    2001-01-01

    Background: The major limitation of coronary stenting remains in-stent restenosis, due to the development of neointimal proliferation. Radioactive stents have demonstrated the ability to reduce this proliferation in the healthy nonatherosclerotic porcine animal model. However, inhibition of tissue proliferation in the in-stent restenotic lesion in a porcine model is not well characterized. The objective of this study was to examine the efficacy and safety of the 32 P radioactive stent for the treatment of in-stent restenosis in a double stent injury model of the porcine coronaries. Methods and Materials: Eighteen coronary arteries in 9 pigs underwent nonradioactive stent (8 mm in length) implantation. Thirty days after the initial stent implantation, a 32 P radioactive stent (18 mm in length) with an activity of 0 and 18 μCi was implanted to cover the initial stent. The swine were killed 30 days after the second stent implantation. Histomorphometric analysis was performed for vessel area (VA), stent strut area (SSA), intimal area (IA), and lumen area (LA). Results: Injury scores, VA, SSA, and LA were similar among the control and radiated groups. Neointimal formation was significantly reduced after placement of radioactive stents as compared to control in both the overlapped (0.93±0.12 vs. 1.31±0.51 mm 2 , p 2 , p 32 P radioactive stents may be safe and effective in reducing neointimal formation leading to in-stent restenosis. Longer follow-up will be required to examine whether these positive findings can be maintained

  18. Manchester iStent study: early results from a prospective UK case series.

    Science.gov (United States)

    Patel, Ilesh; de Klerk, Timothy A; Au, Leon

    2013-01-01

    To evaluate the 6-month efficacy and safety of the iStent microtrabecular bypass stent in patients with open-angle glaucoma. A prospective, uncontrolled, interventional case series. Forty-four eyes with open-angle glaucoma were reported. All subjects underwent ab interno implantation of a single iStent together with (n = 40) or without (n = 4) cataract surgery. Patients were assessed at postoperative week 1, months 1 and 3, and quarterly, thereafter. Data collected included visual acuity, intraocular pressure measurement using Goldmann tonometry, number of glaucoma medications, and number and type of complications. The mean age of the sample was 76.8 years. The mean duration since glaucoma diagnosis was 5.3 years (standard deviation 2.9 years). The mean visual acuity was 0.53 logMAR at baseline that improved to 0.23 at 6 months postoperatively. The mean baseline intraocular pressure was 21.1 mmHg, and this decreased significantly to 16.7 mmHg at 6 months (P control. © 2013 The Authors. Clinical and Experimental Ophthalmology © 2013 Royal Australian and New Zealand College of Ophthalmologists.

  19. Hemi-Intravascular Stenting for Supermicrosurgical Anastomosis

    OpenAIRE

    Kensuke Tashiro, MD; Shuji Yamashita, MD; Mitsunaga Narushima, MD; Isao Koshima, MD; Shimpei Miyamoto, MD

    2017-01-01

    Background:. Although supermicrosurgical anastomosis is a widely known reconstructive microsurgical technique, it is difficult to perform. To expand the clinical use of supermicrosurgery, we used hemi-intravascular stenting (hemi-IVaS), which is performed by inserting an intravascular stent into one side of the vessel. We conducted lymphaticovenular anastomosis, free perforator flap transfer, and fingertip replantation with supermicrosurgical anastomosis using hemi-IVaS technique and examined...

  20. Mechanical Behavior of Fully Expanded Commercially Available Endovascular Coronary Stents

    OpenAIRE

    Tambaca, Josip; Canic, Suncica; Kosor, Mate; Fish, R. David; Paniagua, David

    2011-01-01

    The mechanical behavior of endovascular coronary stents influences their therapeutic efficacy. Through computational studies, researchers can analyze device performance and improve designs. We developed a 1-dimensional finite element method, net-based algorithm and used it to analyze the effects of radial loading and bending in commercially available stents. Our computational study included designs modeled on the Express, Cypher, Xience, and Palmaz stents.

  1. Drug treatment of bothersome lower urinary tract symptoms after ureteric JJ-stent insertion: A contemporary, comparative, prospective, randomised placebo-controlled study, single-centre experience.

    Science.gov (United States)

    Hekal, Ihab A

    2016-12-01

    To provide a guide for medication to alleviate bothersome lower urinary tract symptoms (LUTS) in patients after JJ ureteric stenting. Between June 2011 and June 2015, a prospective randomised placebo-controlled study was conducted on 200 consecutive cases of ureteric stones that required JJ stents. All patients had signed informed consent and JJ-stent placement confirmed by X-ray. The patients were randomised into five groups: A, solifenacin 5 mg; B, trospium chloride 20 mg; C, antispasmodic; and E, α-blocker; and a placebo group (D). A standard model was created to lessen patient selection bias. Eligible patients were enrolled and assessed for side-effects and bothersome LUTS using the validated Ureteric Stent Symptoms Questionnaire. Appropriate statistical analysis was carried out. In all, 150 male patients in the five groups were compared. LUTS were less in groups A and B ( P  JJ-stent insertion, anti-muscarinic medication, namely solifenacin 5 mg or trospium chloride 20 mg, was the best. The advantage of trospium over solifenacin is in the control of frequency rather than the other symptoms. Addition of an α-blocker (alfuzosin 10 mg) is valuable when nocturia is the predominant symptom.

  2. Initial study of sediment antagonism and characteristics of silver nanoparticle-coated biliary stents in an experimental animal model.

    Science.gov (United States)

    Tian, Yigeng; Xia, Mingfeng; Zhang, Shuai; Fu, Zhen; Wen, Qingbin; Liu, Feng; Xu, Zongzhen; Li, Tao; Tian, Hu

    2016-01-01

    Plastic biliary stents used to relieve obstructive jaundice are frequently blocked by sediment, resulting in loss of drainage. We prepared stents coated with silver nanoparticles (AgNPs) and compared their ability to resist sedimentation with Teflon stents in a beagle model of obstructive jaundice. AgNP-coated Teflon biliary stents were prepared by chemical oxidation-reduction and evaluated in an obstructive jaundice model that was produced by ligation of common bile duct (CBD); animals were randomized to two equal groups for placement of AgNP-coated or Teflon control stents. Liver function and inflammatory index were found to be similar in the two groups, and the obstruction was relieved. Stents were removed 21 days after insertion and observed by scanning and transmission electron microscopy. The AgNP coating was analyzed by energy dispersive X-ray analysis (EDXA), and the composition of sediment was assayed by Fourier-transform infrared (FTIR) spectroscopy. Electron microscopy revealed a black, closely adherent AgNP stent coating, with thicknesses of 1.5-6 µm. Sediment thickness and density were greater on Teflon than on AgNP-coated stents. EDXA confirmed the stability and integrity of the AgNP coating before and after in vivo animal experimentation. FTIR spectroscopy identified stent sediment components including bilirubin, cholesterol, bile acid, protein, calcium, and other substances. AgNP-coated biliary stents resisted sediment accumulation in this canine model of obstructive jaundice caused by ligation of the CBD.

  3. Doxazosin oral intake therapy to relieve stent - related urinary symptoms and pain: a prospective, randomized, controlled study

    Directory of Open Access Journals (Sweden)

    Long Zhang

    Full Text Available ABSTRACT Objective: To assess the impact of Doxazosin Oral Intake Therapy on urinary symptoms and pain in patients with indwelling ureteral stents Patients and Methods: A total of 239 patients with ureteral stone-related hydronephrosis who underwent a double-J stent insertion after ureteroscopic lithotripsy were enrolled. Patients were randomized to receive doxazosin cotrolled release 4 mg once daily for 4 weeks or matching placebo. Patients completed the brief-form Chinese version Ureteric Stent Symptom Questionnaire (USSQ and quality of life (QoL score 2 weeks and 4 weeks after stent placement and 4 weeks after stent withdrawal. The analgesic use was also recorded during the stenting period. Results: Patients in Doxazosin Oral Intake Therapy group, in the first 2 weeks and second 2 weeks with the stent in situ, expressed significant lower daytime frequency (p=0.028 and p=0.038, nocturia (p=0.021 and p=0.008 and urgency (p=0.012 and p=0.014, respectively. Similarly, flank pain score, QoL score and analgesic use were also significant less in the stenting period. There was no significant difference in scores of urinary symptoms, pain and QoL during the post-stent period between two cohorts. Conclusions: Doxazosin Oral Intake Therapy reduced stent-related urinary symptoms, pain and the negative impact on QoL.

  4. Efficacy of tamsulosin hydrochloride in relieving "double-J ureteral stent-related morbidity": a randomized placebo controlled clinical study.

    Science.gov (United States)

    Singh, Iqbal; Tripathy, Sambit; Agrawal, Vivek

    2014-12-01

    To evaluate the efficacy of tamsulosin therapy in reducing ureteral double-J stent morbidity by evaluating USSQ, IPSS, QOL and VAS (primary objective) and to evaluate the morbidity and or complication(s) associated with indwelling double-J ureteral stent(s) and to evaluate the safety of tamsulosin therapy for "morbidity associated with double-J stents" by evaluating its tolerability, side effects and adverse events if any (secondary objective) as per protocol. After institutional review board approval, 60 consecutive patients with a double-J ureteral stent inserted after percutaneous nephrolithotomy or ureteroscopic stone treatment were randomly assigned to receive tamsulosin 0.4 mg, or a placebo for 4 weeks. The validated USSQ, VAS and IPSS were completed before stent insertion, at 3 days and 4 weeks after stent insertion and at 2 weeks after stent removal. Data were statistically analyzed for efficacy and tolerability of one drug over the other using Wilcoxon signed-rank test, Mann-Whitney test and Student's t test. Patients receiving tamsulosin compared with the placebo showed significant decrease in urinary index score, pain index score, work performance score, VAS score at loin area, VAS score at flank, VAS score at suprapubic area, average VAS score, need for antibiotics, number of hospital visits (P tamsulosin but, however, the decrease was not significant. No patients discontinued medication because of side effects. We conclude that ureteral stenting using double-J stents with concomitant tamsulosin therapy was generally well tolerated, safe, effective and significantly beneficial in reducing stent morbidity in the majority of our patients. We advocate the routine use of concomitant tamsulosin therapy in eligible patients undergoing ureteral stenting in order to minimize stent morbidity.

  5. Development of a static bioactive stent prototype and dynamic aneurysm-on-a-chip(TM) model for the treatment of aneurysms

    Science.gov (United States)

    Reece, Lisa M.

    Aneurysms are pockets of blood that collect outside blood vessel walls forming dilatations and leaving arterial walls very prone to rupture. Current treatments include: (1) clipping, and (2) coil embolization, including stent-assisted coiling. While these procedures can be effective, it would be advantageous to design a biologically active stent, modified with magnetic stent coatings, allowing cells to be manipulated to heal the arterial lining. Further, velocity, pressure, and wall shear stresses aid in the disease development of aneurysmal growth, but the shear force mechanisms effecting wound closure is elusive. Due to these factors, there is a definite need to cultivate a new stent device that will aid in healing an aneurysm in situ. To this end, a static bioactive stent device was synthesized. Additionally, to study aneurysm pathogenesis, a lab-on-a-chip device (a dynamic stent device) is the key to discovering the underlying mechanisms of these lesions. A first step to the reality of a true bioactive stent involves the study of cells that can be tested against the biomaterials that constitute the stent itself. The second step is to test particles/cells in a microfluidic environment. Therefore, biocompatability data was collected against PDMS, bacterial nanocellulose (BNC), and magnetic bacterial nanocellulose (MBNC). Preliminary static bioactive stents were synthesized whereby BNC was grown to cover standard nitinol stents. In an offshoot of the original research, a two-dimensional microfluidic model, the Aneurysm-on-a-ChipTM (AOC), was the logical answer to study particle flow within an aneurysm "sac" - this was the dynamic bioactive stent device. The AOC apparatus can track particles/cells when it is coupled to a particle image velocimetry software (PIV) package. The AOC fluid flow was visualized using standard microscopy techniques with commercial microparticles/cells. Movies were taken during fluid flow experiments and PIV was utilized to monitor.

  6. Ischaemia of the medullary cone after stent-graft implantation in a patient with abdominal aortic aneurysm - a case study.

    Science.gov (United States)

    Wachowski, Mariusz; Polguj, Michał; Ścibór, Janusz; Majos, Agata

    2018-03-01

    Preoperative visualization of the Adamkiewicz artery - the vessel which is to a great extent responsible for supplying blood to the medullary cone - is an important step which must be taken before initiating restorative procedures in the aorta. We present a case of a 67-year-old patient who underwent an intravascular stent-graft implantation procedure, due to clinical signs of abdominal aortic aneurysm. Routine pre-operative computed tomography examination failed to demonstrate the Adamkiewicz artery. On the second day after the surgery, as a result of unexpected clinical deterioration, an magnetic resonance imaging examination of the lumbar spine was carried out. Based on the magnetic resonance imaging images and clinical manifestations the diagnosis of ischaemia of the medullary cone was made. In our work we also present a deep analysis of the anatomy of small-sized vessels supplying blood to the spinal cord and discuss effective techniques which enable visualization of the Adamkiewicz artery.

  7. Effective treatment of benign biliary strictures with a removable, fully covered, self-expandable metal stent: A prospective, multicenter European study

    Science.gov (United States)

    Schmidt, Arthur; Pickartz, Tilman; Lerch, Markus M; Fanelli, Fabrizio; Fiocca, Fausto; Lucatelli, Pierleone; Cereatti, Fabrizio; Hoffmeister, Albrecht; van Steenbergen, Werner; Kraft, Matthias; Meier, Benjamin

    2016-01-01

    Background Temporary placement of removable, fully covered, self-expandable metal stents (fcSEMS) for treatment of benign biliary strictures (BBS) has been reported to be effective. However, the optimal extraction time point remains unclear and stent migration has been a major concern. Objective The objective of this study was to evaluate the efficacy and safety of this treatment modality using an fcSEMS with a special antimigration design and prolonged stent indwell time. Methods We performed a prospective, single-arm study at six tertiary care centers in Europe. Patients with BBS underwent endoscopic or percutaneous implantation of an fcSEMS (GORE® VIABIL® Biliary Endoprosthesis, W.L. Gore & Associates, Flagstaff, AZ, USA). The devices were scheduled to be removed nine months later, and patients were to return for follow-up for an additional 15 months. Results Forty-three patients were enrolled in the study. Stricture etiology was chronic pancreatitis in the majority of patients (57.5%). All fcSEMS were placed successfully, either endoscopically (76.7%) or percutaneously (23.3%). Stent migration was observed in two patients (5.2%). Primary patency of the SEMS prior to removal was 73.0%. All attempted stent removals were successful. At removal, stricture was resolved or significantly improved without need for further therapy in 78.9% of patients. Stricture recurrence during a follow-up of two years post-implant was observed in two patients. Conclusions Temporary placement of the fcSEMS is a feasible, safe and effective treatment for BBS. The design of the device used in this study accounts for very low migration rates and facilitates easy stent retrieval, even after it has been in place for up to 11 months. PMID:28507752

  8. Effective treatment of benign biliary strictures with a removable, fully covered, self-expandable metal stent: A prospective, multicenter European study.

    Science.gov (United States)

    Schmidt, Arthur; Pickartz, Tilman; Lerch, Markus M; Fanelli, Fabrizio; Fiocca, Fausto; Lucatelli, Pierleone; Cereatti, Fabrizio; Hoffmeister, Albrecht; van Steenbergen, Werner; Kraft, Matthias; Meier, Benjamin; Caca, Karel

    2017-04-01

    Temporary placement of removable, fully covered, self-expandable metal stents (fcSEMS) for treatment of benign biliary strictures (BBS) has been reported to be effective. However, the optimal extraction time point remains unclear and stent migration has been a major concern. The objective of this study was to evaluate the efficacy and safety of this treatment modality using an fcSEMS with a special antimigration design and prolonged stent indwell time. We performed a prospective, single-arm study at six tertiary care centers in Europe. Patients with BBS underwent endoscopic or percutaneous implantation of an fcSEMS (GORE® VIABIL® Biliary Endoprosthesis, W.L. Gore & Associates, Flagstaff, AZ, USA). The devices were scheduled to be removed nine months later, and patients were to return for follow-up for an additional 15 months. Forty-three patients were enrolled in the study. Stricture etiology was chronic pancreatitis in the majority of patients (57.5%). All fcSEMS were placed successfully, either endoscopically (76.7%) or percutaneously (23.3%). Stent migration was observed in two patients (5.2%). Primary patency of the SEMS prior to removal was 73.0%. All attempted stent removals were successful. At removal, stricture was resolved or significantly improved without need for further therapy in 78.9% of patients. Stricture recurrence during a follow-up of two years post-implant was observed in two patients. Temporary placement of the fcSEMS is a feasible, safe and effective treatment for BBS. The design of the device used in this study accounts for very low migration rates and facilitates easy stent retrieval, even after it has been in place for up to 11 months.

  9. Comparison of diamond-like carbon-coated nitinol stents with or without polyethylene glycol grafting and uncoated nitinol stents in a canine iliac artery model

    Science.gov (United States)

    Kim, J H; Shin, J H; Shin, D H; Moon, M-W; Park, K; Kim, T-H; Shin, K M; Won, Y H; Han, D K; Lee, K-R

    2011-01-01

    Objective Neointimal hyperplasia is a major complication of endovascular stent placement with consequent in-stent restenosis or occlusion. Improvements in the biocompatibility of stent designs could reduce stent-associated thrombosis and in-stent restenosis. We hypothesised that the use of a diamond-like carbon (DLC)-coated nitinol stent or a polyethylene glycol (PEG)-DLC-coated nitinol stent could reduce the formation of neointimal hyperplasia, thereby improving stent patency with improved biocompatibility. Methods A total of 24 stents were implanted, under general anaesthesia, into the iliac arteries of six dogs (four stents in each dog) using the carotid artery approach. The experimental study dogs were divided into three groups: the uncoated nitinol stent group (n = 8), the DLC-nitinol stent group (n = 8) and the PEG-DLC-nitinol stent group (n = 8). Results The mean percentage of neointimal hyperplasia was significantly less in the DLC-nitinol stent group (26.7±7.6%) than in the nitinol stent group (40.0±20.3%) (p = 0.021). However, the mean percentage of neointimal hyperplasia was significantly greater in the PEG-DLC-nitinol stent group (58.7±24.7%) than in the nitinol stent group (40.0±20.3%) (p = 0.01). Conclusion Our findings indicate that DLC-coated nitinol stents might induce less neointimal hyperplasia than conventional nitinol stents following implantation in a canine iliac artery model; however, the DLC-coated nitinol stent surface when reformed with PEG induces more neointimal hyperplasia than either a conventional or DLC-coated nitinol stent. PMID:21325363

  10. Stent placement for benign colonic stenosis: case report, review of the literature, and animal pilot data.

    Science.gov (United States)

    Geiger, Timothy M; Miedema, Brent W; Tsereteli, Zurab; Sporn, Emanuel; Thaler, Klaus

    2008-10-01

    Permanent metal stent placement for malignant intestinal obstruction has been proven to be efficient. Temporary stents for benign conditions of the colon and rectum are less studied. This is a case study, review of the literature, and observation from an animal model on placement of stents in the colorectum for benign disease. A 55-year-old man presented with recurrent obstructions from a benign stricture of the distal sigmoid colon. After failed balloon dilations, a polyester coated stent was placed. The purpose of the stent was to improve symptoms and avoid surgery. The stent was expelled after 5 days. We conducted a literature review of stents placed for benign colorectal strictures and an animal study to evaluate stent migration. In the literature, there were 53 reports of uncovered metal stents, four covered metal stents, and six polyester stents. Patency rates were 71%, and migration rate was 43%. Migration occurred earlier with polyester stents (mean=8 days) versus covered (32 days) or uncovered metal stents (112 days). Severe complications were seen in 23% of patients. Four 45-kg pigs underwent rectosigmoid transection with a 21-mm anastomosis and endoscopic placement of a Polyflex stent. Two stents were secured with suture. Stents without fixation were expelled within 24 h of surgery. Stents with fixation were expelled between postoperative days 2 and 14. Stents for the treatment of benign colorectal strictures are safe, with comparable patency rates between stent types. Metal stents can cause severe complications. In a pig model, covered polyester stents tend to migrate early even with fixation. Further investigation needs to focus on new stent designs and/or better fixation.

  11. Stent insertion in patients with malignant biliary obstruction: problems of the Hanaro stent

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Jae Hyun; Seong, Chang Kyu; Shin, Tae Beom; Kim, Yong Joo [School of Medicine, Kyungpook National Univ., Daegu (Korea, Republic of); Jung, Gyoo Sik [School of Medicine, Kosin National Univ., Pusan (Korea, Republic of); Park, Byeung Ho [School of Medicine, Donga National Univ., Pusan (Korea, Republic of)

    2002-07-01

    To investigate the problems of the Hanaro stent (Solco Intermed, Seoul, Korea) when used in the palliative treatment of patients with inoperable malignant biliary obstruction. Between January 2000 and May 2001, the treatment of 46 patients with malignant biliary obstruction involved percutaneous placement of the Hanaro stent. Five patients encountered problems during removal of the stent's introduction system. The causes of obstruction were pancreatic carcinoma (n=2), cholangiocarcinoma (n=2), and gastric carcinoma with biliary invasion (n=1). In one patient, percutaneous transhepatic cholangiography and stent insertion were performed as a one-step procedure, while the others underwent conventional percutaneous transhepatic biliary drainage for at least two days prior to stent insertion. A self-expandable Hanaro stent, 8-10 mm in deameter and 50-100 mm in lengh, and made from a strand of nitinol wire, was used in all cases. Among the five patients who encountered problems, breakage of the olive tip occourred in three, upward displacement of the stent in two, and improper expansion of the distal portion of the stent, unrelated with the obstruction site, in one. The broken olive tip was pushed to the duodenum in two cases and to the peripheral intrahepatic duct in one. Where the stent migrated during withdrawal of its introduction system, an additional stent was inserted. In one case, the migrated stent was positioned near the liver capsule and the drainage catheter could not be removed. Although the number of patients in this study was limited, some difficulties were encountered in withdrawing the stent's introduction system. To prevent the occurrence of this unusual complication, the stent should be appropriately expansile, and shape in the olive tip should be considered.

  12. Self-expandable metallic stents vs. plastic stents for endoscopic biliary drainage in hepatocellular carcinoma.

    Science.gov (United States)

    Chung, Kwang Hyun; Lee, Sang Hyub; Park, Jin Myung; Lee, Jae Min; Ahn, Dong-Won; Ryu, Ji Kon; Kim, Yong-Tae

    2015-06-01

    The patency of self-expandable metallic stents (SEMS) is known to be better than plastic stents in the palliation of malignant biliary obstruction. However, data are scarce for obstructive jaundice caused by hepatocellular carcinoma (HCC). This study aimed to compare SEMSs and plastic stents for the palliation of obstructive jaundice in unresectable HCC. A total of 96 patients who underwent endoscopic retrograde biliary drainage with SEMSs or plastic stents were included in this retrospective analysis. The rate of successful biliary drainage, adverse events, stent patency duration, and patient survival were compared between the SEMS (n = 36) and plastic stent (n = 60) groups. The rate of successful biliary drainage was similar between the SEMS and plastic stent groups (25/36 [69.4 %] vs. 39/60 [65.0 %]; P = 0.655). Adverse events occurred in 6 patients (16.7 %) in the SEMS group and 13 patients (21.7 %) in the plastic stent group (P = 0.552). The median patency duration was also similar between the two groups (60 vs. 68 days; P = 0.396). The median patient survival was longer in the plastic stent group than in the SEMS group (123 vs. 48 days; P = 0.005). SEMSs were not superior to plastic stents for the palliation of malignant biliary obstruction in HCC with regard to successful drainage, stent patency, and adverse events. Patient survival was better in the plastic stent group. Given the lower cost, plastic stents could be a favorable option for malignant biliary obstruction caused by HCC. © Georg Thieme Verlag KG Stuttgart · New York.

  13. Prophylactic urethral stenting with Memokath® 028SW in prostate cancer patients undergoing prostate 125I seed implants: phase I/II study

    Directory of Open Access Journals (Sweden)

    Samuel T. Chao

    2011-03-01

    Full Text Available Purpose: To study the feasibility/toxicity of urethral stenting with the Memokath® 028SW stent in patients undergoing prostate implant (PI for prostate adenocarcinoma. Material and methods: An Investigational Device Exemption from the Food and Drug Administration (FDA and institutional review board (IRB approval were obtained. Twenty patients enrolled. Baseline American Urological Association (AUA score was obtained prior to PI. Follow-up information was obtained with weekly phone calls for the first 12 weeks and biweekly calls for the next 12 weeks to assess toxicity and AUA score. Removal of the stent was planned at six months after PI, or earlier due to excessive toxicity/patient request. Results: Median age was 66.5 years. The median prostate volume was 39 cc (range: 10-90. The median baseline AUA score was 7.5 (range: 1-21. Three patients required intermittent self-catheterization (ISC within 3 days after PI. No patients required ISC beyond day 3 after PI. The median duration of ISC was 1 day (range: 1-2. AUA scores returned to baseline values 6 weeks after PI. The week 6 AUA score was 10 (range: 4-16. Seven patients (35% underwent early removal because of patient preference. The reasons were: incontinence (n = 3, discomfort (n = 2, hematuria (n = 1, and obstructive symptoms (n = 1. The median time of stent removal in these patients was 13.9 weeks (range: 0.9-21.4. Thirteen patients (65% had ISC and/or urinary catheterization post stent removal. Median time for ISC use was 10 days (range: 1-90. Conclusions: Urethral stenting with Memokath® in patients undergoing PI was feasible, but resulted in relatively high rate of urinary incontinence and discomfort. Given the adverse effects experienced by patients of this study, further studies should focus only on patients with highest risk of urinary obstruction from PI or those with obstruction needing ISC.

  14. A prospective multicenter study on self-expandable metallic stents as a bridge to surgery for malignant colorectal obstruction in Japan: efficacy and safety in 312 patients.

    Science.gov (United States)

    Saito, Shuji; Yoshida, Shuntaro; Isayama, Hiroyuki; Matsuzawa, Takeaki; Kuwai, Toshio; Maetani, Iruru; Shimada, Mamoru; Yamada, Tomonori; Tomita, Masafumi; Koizumi, Koichi; Hirata, Nobuto; Kanazawa, Hideki; Enomoto, Toshiyuki; Sekido, Hitoshi; Saida, Yoshihisa

    2016-09-01

    Endoscopic stenting with a self-expandable metallic stent (SEMS) is a widely accepted procedure for malignant colonic obstruction. The Colonic Stent Safe Procedure Research Group conducted the present prospective feasibility study. Our objectives were to estimate the safety and feasibility of SEMS placement as a bridge to surgery (BTS) for malignant colorectal obstruction. We conducted a prospective, observational, single-arm, multicenter clinical trial from March 2012 to October 2013. Each patient was treated with an uncovered WallFlex enteral colonic stent. Patients were followed up until discharge after surgery. A total of 518 consecutive patients were enrolled in this study. The cohort intended for BTS consisted of 312 patients (61 %), and the stent could be released in 305 patients. Technical and clinical success rates were 98 and 92 %, respectively. Elective surgery was performed in 297 patients, and emergency surgery was performed in eight patients for the treatment of complications. The overall preoperative complication rate was 7.2 %. Major complications, including perforation, occurred in 1.6 %, persistent colonic obstruction occurred in 1.0 %, and stent migration occurred in 1.3 % patients. The median time from SEMS to surgery was 16 days. Silent perforations were observed in 1.3 %. Open and laparoscopic surgery was performed in 121 and 184 patients, respectively. The tumor could be resected in 297 patients. The primary anastomosis rate was 92 %. The rate of anastomotic leakage was 4 %, and the overall stoma creation rate was 10 %. The median duration of hospitalization following surgery was 12 days. Overall postoperative morbidity and mortality rates were 16 and 0.7 %, respectively. This largest, multicenter, prospective study demonstrates the feasibility of SEMS placement as a BTS for malignant colorectal obstruction. SEMS serves as a safe and effective BTS with acceptable stoma creation and complication rates in patients with acute

  15. Malignant duodenal obstructions: palliative treatment with covered expandable nitinol stent

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Chul; Jung, Gyoo Sik; Lee, Sang Hee; Kim, Sung Min; Oh, Kyung Seung; Huh, Jin Do; Cho, Young Duk [College of Medicine, Kosin Univ, Pusan (Korea, Republic of); Song, Ho Young [College of Medicine, Ulsan Univ., Seoul (Korea, Republic of)

    2002-04-01

    To evaluate the feasibility and clinical effectiveness of using a polyurethane-covered expandable nitinol stent in the palliative treatment of malignant duodenal obstruction. Under fluoroscopic guidance, a polyurethane-covered expandable nitinol stent was placed in 12 consecutive patients with malignant duodenal obstructions. All presented with severe nausea and recurrent vomiting. The underlying causes of obstruction were duodenal carcinoma (n=4), pancreatic carcinoma (n=4), gall bladder carcinoma (n=2), distal CBD carcinoma (n=1), and uterine cervical carcinoma (n=1). The sites of obstruction were part I (n=1), part II (n=8), and III (n=3). Due to pre-existing jaundice, eight patients with part II obstructions underwent biliary decompression prior to stent placement. An introducer sheath with a 6-mm outer diameter and stents 16 mm in diameter were employed, and to place the stent, and after-loading technique was used. Stent placement was technically successful in ten patients, and no procedural complications occuured. In one of two patients in whom there was technical failure, and in whom the obstructions were located in part III, the stent was placed transgastrically. Stent migration occurred in one patient four days after the procedure, and treatment involved the palcement of a second, uncovered, nitinol stent. After stent placement, symptoms improved in all patients. During follow-up, obstructive symptoms due to stent stenosis (n=1), colonic obstruction (n=1), and multiple small bowel obstruction (n=1) recurred in three patients. Two of these were treated by placing additional stents in the duodenum and colon, respectively. One of the eight patients in whom a stent was placed in the second portion of the duodenum developed jaundice. The patients died a mean 14 (median, 9) weeks after stent placement. The placement of a polyurethane-covered expandable nitinol stent seems to be technically feasible, safe and effective for the palliative treatment of malignant

  16. Imaging of coronary artery stents using multislice computed tomography: in vitro evaluation

    International Nuclear Information System (INIS)

    Maintz, David; Juergens, Kai-Uwe; Heindel, Walter; Fischbach, Roman; Wichter, Thomas; Grude, Matthias

    2003-01-01

    The aim of this study was to evaluate imaging features of different coronary artery stents during multislice CT Angiography (MSCTA). Nineteen stents made of varying material (steel, nitinol, tantalum) and of varying stent design were implanted in plastic tubes with an inner diameter of 3 mm to simulate a coronary artery. The tubes were filled with iodinated contrast material diluted to 200 Hounsfield units (HU), closed at both ends and positioned in a plastic container filled with oil (-70 HU). The MSCT scans were obtained perpendicular to the stent axes (detector collimation 4 x 1 mm, table feed 2 mm/rotation, 300 mAs, 120 kV). Axial images and multiplanar reformations were evaluated regarding artifact size, lumen visibility, and intraluminal attenuation values. Artifacts characterized by artifactual thickening of the stent struts leading to apparent reduction in the lumen diameter and increased intraluminal attenuation values were observed in all cases. The stent lumen was totally obscured in the Wiktor stent, the Wallgraft stent, and the Nir Royal stent. Partial residual of the stent lumen could be visualized in all other utilized stent products (artificial lumen reductions ranged from 62% in the V-Flex stent to 94% in the Bx Velocity stent). Parts of the stent lumen can be visualized in most coronary artery stents; however, detectability of in-stent stenoses remains to be evaluated for each stent type. (orig.)

  17. Hemi-Intravascular Stenting for Supermicrosurgical Anastomosis

    Science.gov (United States)

    Yamashita, Shuji; Narushima, Mitsunaga; Koshima, Isao; Miyamoto, Shimpei

    2017-01-01

    Background: Although supermicrosurgical anastomosis is a widely known reconstructive microsurgical technique, it is difficult to perform. To expand the clinical use of supermicrosurgery, we used hemi-intravascular stenting (hemi-IVaS), which is performed by inserting an intravascular stent into one side of the vessel. We conducted lymphaticovenular anastomosis, free perforator flap transfer, and fingertip replantation with supermicrosurgical anastomosis using hemi-IVaS technique and examined its usefulness. Methods: Between January 2013 and February 2015, 11 anastomoses in 11 cases of lymphaticovenular anastomosis for lymphedema patients, 14 anastomoses in 7 cases of free perforator flap transfer with supermicrosurgical perforator-to-perforator anastomosis, and 9 anastomoses in 5 cases of fingertip replantation were performed using hemi-IVaS. Time required for anastomosis and complications were examined. Flap survival rate was also examined in free perforator flap transfer cases and fingertip replantation cases. Results: In all cases, anastomoses were performed without complications such as inadvertent catching of the back wall of the vessel during the procedure or the need for reanastomoses. The average time required to complete the anastomosis was 16.4 ± 3.20 minutes using the hemi IVaS technique. All flaps survived in the supermicrosurgical perforator-to-perforator anastomosis as well as fingertip replantation cases. Conclusions: Hemi-IVaS could be a useful alternative to conventional intravascular stenting techniques and is also effective for supermicrosurgical perforator-to-perforator anastomosis. Further studies are needed to improve the success rate and to explore its other possible utilizations in supermicrosurgery. PMID:29263952

  18. Phacoemulsification combined with a new ab interno gel stent to treat open-angle glaucoma: Pilot study.

    Science.gov (United States)

    Sheybani, Arsham; Lenzhofer, Markus; Hohensinn, Melchior; Reitsamer, Herbert; Ahmed, Iqbal Ike K

    2015-09-01

    To study the effect on intraocular pressure (IOP) of implanting a new gelatin stent at the time of cataract surgery in the treatment of open-angle glaucoma (OAG). Multicenter university and private-practice settings. Nonrandomized prospective clinical trial. The implantation of 2 models of a gelatin stent (Xen140 and Xen63) was performed at the time of cataract surgery without mitomycin-C. Complete success was defined as a postoperative IOP of less than 18 mm Hg and more than a 20% reduction in IOP at 12 months without glaucoma medication. Failure was defined as loss of light perception vision or worse, a need for additional glaucoma surgery, or less than a 20% reduction in the IOP from baseline. The study included 37 eyes of 37 patients. The mean preoperative IOP was 22.4 mm Hg ± 4.2 (SD) on 2.5 ± 1.4 medication classes. Twelve months postoperatively, the mean IOP was reduced to 15.4 ± 3.0 mm Hg on 0.9 ± 1.0 medication classes (P Ahmed is a paid consultant to Aquesys, Inc. No other author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  19. Outcomes and complications of self-expanding metal stent placement for malignant colonic obstruction in a single-center study.

    Science.gov (United States)

    Stankiewicz, Rafał; Kozieł, Sławomir; Pertkiewicz, Jan; Zieniewicz, Krzysztof

    2018-03-01

    Approximately 20% of cases of colorectal cancer are accompanied by acute colonic obstruction. While emergency colonic surgery is associated with high mortality and morbidity rates, placement of a self-expanding metal stent (SEMS) has been suggested as an alternative method. The SEMS placement can serve as either a definitive treatment in palliative cases or a bridge to surgery. To summarize the experience of our center in the treatment of malignant colonic obstruction using SEMS placement. A retrospective review was conducted of all patients who underwent a SEMS placement for colorectal stricture in the study period. The procedures were performed under fluoroscopic guidance with colonoscopic assistance, and uncovered stents were used in all patients. The study population consisted of 28 patients treated with SEMS placement due to malignant colonic obstruction. The majority of procedures were performed with palliative intent. The overall technical success rate was 96.5%, and clinical success was achieved in all of the successfully placed SEMSs. One fatal complication due to colonic perforation occurred. In the bridge-to-surgery group, all patients experienced tumor resection with no stoma creation. The SEMS placement is an optimal treatment in the vast majority of acute colonic obstruction cases. Due to the possibility of potentially fatal complications, SEMS procedures should be performed by proficient endoscopists.

  20. Optical coherence tomography findings after chronic total occlusion interventions: Insights from the “AngiographiC evaluation of the everolimus-eluting stent in chronic Total occlusions” (ACE-CTO) study (NCT01012869)

    Energy Technology Data Exchange (ETDEWEB)

    Sherbet, Daniel P.; Christopoulos, Georgios; Karatasakis, Aris; Danek, Barbara Anna; Kotsia, Anna; Navara, Rachita; Michael, Tesfaldet T.; Roesle, Michele; Rangan, Bavana V.; Haagen, Donald [VA North Texas Healthcare System and University of Texas Southwestern Medical Center, Dallas, TX (United States); Garcia, Santiago [Minneapolis VA Healthcare System and University of Minnesota, Minneapolis, MN (United States); Maniu, Calin [Bon Secours Health System, Suffolk, VA (United States); Pershad, Ashish [Banner Good Samaritan Medical Center, Phoenix, AZ (United States); Abdullah, Shuaib M.; Hastings, Jeffrey L.; Kumbhani, Dharam J.; Luna, Michael; Addo, Tayo; Banerjee, Subhash [VA North Texas Healthcare System and University of Texas Southwestern Medical Center, Dallas, TX (United States); Brilakis, Emmanouil S., E-mail: esbrilakis@gmail.com [VA North Texas Healthcare System and University of Texas Southwestern Medical Center, Dallas, TX (United States)

    2016-10-15

    Background: There is limited information on optical coherence tomography (OCT) findings after percutaneous coronary intervention (PCI) of chronic total occlusions (CTOs). OCT allows high resolution imaging that can enhance understanding of the vascular response after stenting of chronically occluded vessels. Methods: The Angiographic Evaluation of the Everolimus-Eluting Stent in Chronic Total Occlusions (ACE-CTO) study collected angiographic and clinical outcomes from 100 patients undergoing CTO PCI with the everolimus-eluting stent (EES). OCT was performed 8-months post stenting in 62 patients. Every third frame was analyzed throughout the course of the stented arterial segment. Lumen contours were semi-automatically traced and stent struts were manually delineated, with automatic measurement of the strut to lumen distance. Struts on the luminal side of the lumen contour were classified as malapposed if the distance to the lumen contour exceeded 0.108 mm. Results: A total of 44,450 struts in 6047 frames were analyzed, of which 4113 9.3%, 95% confidence intervals [CI] 9.0% to 9.5%) were malapposed and 1230 (2.8%, 95% CI 2.6% to 2.9%) were uncovered. Fifty-five of 62 patients (88.7%, 95% CI 78.5% to 98.4%) had at least one malapposed stent strut and 50 patients (80.7%, 95% CI 69.2% to 88.6%) had at least one uncovered stent strut. Mean strut-intimal thickness of the apposed and malapposed struts was 0.126 ± 0.140 mm and − 0.491 ± 0.440 mm, respectively. Conclusion: High rates of stent strut malapposition and incomplete stent strut coverage were observed after CTO PCI using EES, highlighting unique challenges associated with stent implantation in CTOs. - Highlights: • Percutaneous coronary intervention with drug-eluting stents for chronic total occlusion is associated with a 40% rate of binary in-stent restenosis at 8 months • Of patients who receive a drug eluting stent for a chronic total occlusion 88.7% will have stent strut malapposition and 80.7% will

  1. Influence of a pressure gradient distal to implanted bare-metal stent on in-stent restenosis after percutaneous coronary intervention

    DEFF Research Database (Denmark)

    Jensen, Lisette Okkels; Thayssen, Per; Thuesen, Leif

    2007-01-01

    pullback recording in the entire length of the artery. METHODS AND RESULTS: In 98 patients with angina pectoris, 1 de novo coronary lesion was treated with a bare-metal stent. After stent implantation, pressure wire measurements (P(d)=mean hyperemic coronary pressure and P(a)=mean aortic pressure) were......-