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Sample records for ptfe covered stent

  1. Treatment of Malignant Biliary Obstruction with a PTFE-Covered Self-Expandable Nitinol Stent

    International Nuclear Information System (INIS)

    Han, Young-Min; Kwak, Hyo-Sung; Jin, Gong-Yong; Lee, Seung-Ok; Chung, Gyung-Ho

    2007-01-01

    We wanted to determine the technical and clinical efficacy of using a PTFE-covered self-expandable nitinol stent for the palliative treatment of malignant biliary obstruction. Thirty-seven patients with common bile duct strictures caused by malignant disease were treated by placing a total of 37 nitinol PTFE stents. These stents were covered with PTFE with the exception of the last 5 mm at each end; the stent had an unconstrained diameter of 10 mm and a total length of 50 80 mm. The patient survival rate and stent patency rate were calculated by performing Kaplan-Meier survival analysis. The bilirubin, serum amylase and lipase levels before and after stent placement were measured and then compared using a Wilcoxon signed-rank test. The average follow-up duration was 27.9 weeks (range: 2 81 weeks). Placement was successful in all cases. Seventy-six percent of the patients (28/37) experienced adequate palliative drainage for the remainder of their lives. There were no immediate complications. Three patients demonstrated stent sludge occlusion that required PTBD (percutaneous transhepatic biliary drainage) irrigation. Two patients experienced delayed stent migration with stone formation at 7 and 27 weeks of follow-up, respectively. Stent insertion resulted in acute elevations of the amylase and lipase levels one day after stent insertion in 11 patients in spite of performing endoscopic sphincterotomy (4/6). The bilirubin levels were significantly reduced one week after stent insertion (p < 0.01). The 30-day mortality rate was 8% (3/37), and the survival rates were 49% and 27% at 20 and 50 weeks, respectively. The primary stent patency rates were 85%, and 78% at 20 and 50 weeks, respectively. The PTFE-covered self-expandable nitinol stent is safe to use with acceptable complication rates. This study is similar to the previous studies with regard to comparing the patency rates and survival rates

  2. Treatment of Malignant Biliary Obstruction with a PTFE-Covered Self-Expandable Nitinol Stent

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    Han, Young-Min; Kwak, Hyo-Sung; Jin, Gong-Yong; Lee, Seung-Ok; Chung, Gyung-Ho [Chonbuk National University Medical School and Hospital, Chonju (Korea, Republic of)

    2007-10-15

    We wanted to determine the technical and clinical efficacy of using a PTFE-covered self-expandable nitinol stent for the palliative treatment of malignant biliary obstruction. Thirty-seven patients with common bile duct strictures caused by malignant disease were treated by placing a total of 37 nitinol PTFE stents. These stents were covered with PTFE with the exception of the last 5 mm at each end; the stent had an unconstrained diameter of 10 mm and a total length of 50 80 mm. The patient survival rate and stent patency rate were calculated by performing Kaplan-Meier survival analysis. The bilirubin, serum amylase and lipase levels before and after stent placement were measured and then compared using a Wilcoxon signed-rank test. The average follow-up duration was 27.9 weeks (range: 2 81 weeks). Placement was successful in all cases. Seventy-six percent of the patients (28/37) experienced adequate palliative drainage for the remainder of their lives. There were no immediate complications. Three patients demonstrated stent sludge occlusion that required PTBD (percutaneous transhepatic biliary drainage) irrigation. Two patients experienced delayed stent migration with stone formation at 7 and 27 weeks of follow-up, respectively. Stent insertion resulted in acute elevations of the amylase and lipase levels one day after stent insertion in 11 patients in spite of performing endoscopic sphincterotomy (4/6). The bilirubin levels were significantly reduced one week after stent insertion (p < 0.01). The 30-day mortality rate was 8% (3/37), and the survival rates were 49% and 27% at 20 and 50 weeks, respectively. The primary stent patency rates were 85%, and 78% at 20 and 50 weeks, respectively. The PTFE-covered self-expandable nitinol stent is safe to use with acceptable complication rates. This study is similar to the previous studies with regard to comparing the patency rates and survival rates.

  3. Percutaneous Palliation of Pancreatic Head Cancer: Randomized Comparison of ePTFE/FEP–Covered Versus Uncovered Nitinol Biliary Stents

    International Nuclear Information System (INIS)

    Krokidis, Miltiadis; Fanelli, Fabrizio; Orgera, Gianluigi; Tsetis, Dimitrios; Mouzas, Ioannis; Bezzi, Mario; Kouroumalis, Elias; Pasariello, Roberto; Hatzidakis, Adam

    2011-01-01

    The purpose of this study was to compare the clinical effectiveness of expanded polytetrafluoroethylene/fluorinated-ethylene-propylene (ePTFE/FEP)–covered stents with that of uncovered nitinol stents for the palliation of malignant jaundice caused by inoperable pancreatic head cancer. Eighty patients were enrolled in a prospective randomized study. Bare nitinol stents were used in half of the patients, and ePTFE/FEP–covered stents were used in the remaining patients. Patency, survival, complications, and mean cost were calculated in both groups. Mean patency was 166.0 ± 13.11 days for the bare-stent group and 234.0 ± 20.87 days for the covered-stent group (p = 0.007). Primary patency rates at 3, 6, and 12 months were 77.5, 69.8, and 69.8% for the bare-stent group and 97.5, 92.2, and 87.6% for the covered-stent group, respectively. Mean secondary patency was 123.7 ± 22.5 days for the bare-stent group and 130.3 ± 21.4 days for the covered-stent group. Tumour ingrowth occurred exclusively in the bare-stent group in 27.5% of cases (p = 0.002). Median survival was 203.2 ± 11.8 days for the bare-stent group and 247.0 ± 20 days for the covered-stent group (p = 0.06). Complications and mean cost were similar in both groups. Regarding primary patency and ingrowth rate, ePTFE/FEP–covered stents have shown to be significantly superior to bare nitinol stents for the palliation of malignant jaundice caused by inoperable pancreatic head cancer and pose comparable cost and complications. Use of a covered stent does not significantly influence overall survival rate; nevertheless, the covered endoprosthesis seems to offer result in fewer reinterventions and better quality of patient life.

  4. Self-expandable polytetrafluoroethylene (PTFE)-covered nitinol stent for the palliative treatment of malignant biliary obstruction

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    Yoo, Oong; Jung, Gyoo Sik; Han, Byung Hoon; Shin, Dong Hoon [Gospel Hospital, College of Medicine, Kosin University, Busan (Korea, Republic of); Ko, Ji Ho [Masan Samsung Medical Center, Sungkyunkwan University School of Medicine, Masan (Korea, Republic of)

    2008-06-15

    We wanted to determine the technical and clinical efficacy of placing a self-expandable PTFE-covered nitinol stent for the management of inoperable malignant biliary obstruction. Thirty six patients with inoperable malignant biliary obstructions were treated by placement of self-expandable PTFE-covered nitinol stents (S and G Biotech Corporation, Seongnam, Korea). Clinical evaluation was done with assessment of the serum bilirubin and alkaline phosphatase levels, which were measured before and after stent placement within 1 week, at 1 month and at 3 months. The patient survival rate and stent patency rate were calculated with performing Kaplan-Meier survival analysis. Successful stent placement was achieved in all the patients without procedure-related complication. Pancreatitis as an early complication occurred in two cases. The serum bilirubin and alkaline phosphatase levels were significantly decreased after the procedure. During the follow-up, recurrent obstructive jaundice occurred in six cases; stent migration occurred in four cases and tumor overgrowth occurred in two cases. The survival rates were 97%, 80%, 67% and 59% at 1, 3, 6 and 9 months, respectively. The stent patency rates were 96%, 92%, 86% and 86% at 1, 3, 6 and 9 months, respectively. Self-expandable PTFE-covered nitinol stent placement seems to be technically feasible and effective for the palliative treatment of malignant biliary obstruction.

  5. Self-expandable polytetrafluoroethylene (PTFE)-covered nitinol stent for the palliative treatment of malignant biliary obstruction

    International Nuclear Information System (INIS)

    Yoo, Oong; Jung, Gyoo Sik; Han, Byung Hoon; Shin, Dong Hoon; Ko, Ji Ho

    2008-01-01

    We wanted to determine the technical and clinical efficacy of placing a self-expandable PTFE-covered nitinol stent for the management of inoperable malignant biliary obstruction. Thirty six patients with inoperable malignant biliary obstructions were treated by placement of self-expandable PTFE-covered nitinol stents (S and G Biotech Corporation, Seongnam, Korea). Clinical evaluation was done with assessment of the serum bilirubin and alkaline phosphatase levels, which were measured before and after stent placement within 1 week, at 1 month and at 3 months. The patient survival rate and stent patency rate were calculated with performing Kaplan-Meier survival analysis. Successful stent placement was achieved in all the patients without procedure-related complication. Pancreatitis as an early complication occurred in two cases. The serum bilirubin and alkaline phosphatase levels were significantly decreased after the procedure. During the follow-up, recurrent obstructive jaundice occurred in six cases; stent migration occurred in four cases and tumor overgrowth occurred in two cases. The survival rates were 97%, 80%, 67% and 59% at 1, 3, 6 and 9 months, respectively. The stent patency rates were 96%, 92%, 86% and 86% at 1, 3, 6 and 9 months, respectively. Self-expandable PTFE-covered nitinol stent placement seems to be technically feasible and effective for the palliative treatment of malignant biliary obstruction

  6. Bronchobiliary Fistula Treated by Self-expanding ePTFE-Covered Nitinol Stent-Graft

    International Nuclear Information System (INIS)

    Gandini, Roberto; Konda, Daniel; Tisone, Giuseppe; Pipitone, Vincenzo; Anselmo, Alessandro; Simonetti, Giovanni

    2005-01-01

    A 71-year-old man, who had undergone right hepatectomy extended to the caudate lobe with terminolateral Roux-en-Y left hepatojejunostomy for a Klatskin tumor, developed bilioptysis 3 weeks postoperatively due to bronchobiliary fistula. Percutaneous transhepatic cholangiography revealed a non-dilated biliary system with contrast medium extravasation to the right subphrenic space through a resected anomalous right posterior segmental duct. After initial unsuccessful internal-external biliary drainage, the fistula was sealed with a VIATORR covered self-expanding nitinol stent-graft placed with its distal uncovered region in the hepatojejunal anastomosis and the proximal ePTFE-lined region in the left hepatic duct. A 10-month follow-up revealed no recurrence of bilioptysis and confirmed the complete exclusion of the bronchobiliary fistula

  7. 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.

  8. Management of malignant biliary obstruction: Technical and clinical results using an expanded polytetrafluoroethylene fluorinated ethylene propylene (ePTFE/FEP)-covered metallic stent after 6-year experience

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    Fanelli, Fabrizio; Orgera, Gianluigi; Bezzi, Mario; Rossi, Plinio; Allegritti, Massimiliano; Passariello, Roberto [University of Rome, Department of Radiological Sciences, Rome (Italy)

    2008-05-15

    To evaluate the efficacy and safety of an expanded polytetrafluoroethylene-fluorinated ethylene-propylene (ePTFE/FEP)-covered metallic stent in the management of malignant biliary obstruction. Eighty consecutive patients with malignant common bile duct strictures were treated by placement of 83 covered metallic stents. The stent-graft consists of an inner ePTFE/FEP lining and an outer supporting structure of nitinol wire. Clinical evaluation, assessment of serum bilirubin and liver enzyme levels were analyzed before biliary drainage, before stent-graft placement and during the follow-up period at 1, 3, 6, 9 and 12 months. Technical success was obtained in all cases. After a mean follow-up of 6.9{+-}4.63 months, the 30-day mortality rate was 14.2%. Survival rates were 40% and 20.2% at 6 and 12 months, respectively. Stent-graft patency rates were 95.5%, 92.6% and 85.7% at 3, 6 and 12 months, respectively. Complications occurred in five patients (6.4%); among these, acute cholecystitis was observed in three patients (3.8%). A stent-graft occlusion rate of 9% was observed. The percentage of patients undergoing lifetime palliation (91%) and the midterm patency rate suggest that placement of this ePTFE/FEP-covered stent-graft is safe and highly effective in achieving biliary drainage in patients with malignant strictures of the common bile duct. (orig.)

  9. Transjugular Intrahepatic Portosystemic Shunts in Patients with Cirrhosis with Refractory Ascites: Comparison of Clinical Outcomes by Using 8- and 10-mm PTFE-covered Stents.

    Science.gov (United States)

    Miraglia, Roberto; Maruzzelli, Luigi; Tuzzolino, Fabio; Petridis, Ioannis; D'Amico, Mario; Luca, Angelo

    2017-07-01

    Purpose To compare the efficacy and complications of transjugular intrahepatic portosystemic shunt (TIPS) creation performed by using a 10-mm or an 8-mm-diameter polytetrafluoroethylene (PTFE)-covered stent in a consecutive series of patients with cirrhosis with refractory ascites (RA). Materials and Methods The institutional review board approved this retrospective study and informed consent was waived. One hundred seventy-one patients with RA (mean age, 58.7 years ± 10.3; 95% confidence interval [CI]: 57.2 years, 60.3 years) had undergone TIPS placement by using 10-mm (60 patients) or 8-mm (111 patients) covered stent between January 2004 and December 2012. Median follow-up time was 16.8 months (range, 3.4-84.8 months). Hemodynamic changes, incidence of hepatic encephalopathy, and long-term (>3 months) need for paracentesis after TIPS placement were evaluated and calculated by using the Kaplan-Meier method and were compared by using the log-rank test. Results Pre-TIPS demographics and clinical characteristics of the two groups were comparable. The portosystemic gradient before TIPS was 17.0 mm Hg ± 4.2 (95% CI: 15.9 mm Hg, 18.1 mm Hg) in the 10-mm group versus 16.1 mm Hg ± 3.7 (95% CI: 15.4 mm Hg, 16.8 mm Hg) in the 8-mm group (P = .164). After TIPS, the portosystemic gradient was 6.5 mm Hg ± 3.4 (95% CI: 5.7 mm Hg, 7.4 mm Hg) in the 10-mm group versus 7.5 mm Hg ± 2.6 (95% CI: 6.9 mm Hg, 7.9 mm Hg) in the 8-mm group (P = .039). The long-term need for paracentesis was greater in the 8-mm group (64 of 111 patients [58%] vs 18 of 60 patients [31%], P = .003). Overall, hepatic encephalopathy was similar in both groups (45 of 111 patients [41%] vs 26 of 60 patients [44%], P = .728). Conclusion A10-mm PTFE-covered stent leads to better control of RA secondary to portal hypertension in patients with cirrhosis, compared with an 8-mm stent, without increasing the incidence of hepatic encephalopathy. © RSNA, 2017.

  10. Optimal Covering Material for Stent-Grafts Placed in the Portal Vein in a Canine Model

    International Nuclear Information System (INIS)

    Ishii, Seigo; Sato, Morio; Sonomura, Tetsuo; Yamada, Katsuyuki; Tanihata, Hirohiko; Ishikawa, Hime; Terada, Masaki; Sahara, Shinya; Kawai, Nobuyuki; Kimura, Masashi; Mori, Ichiro

    2005-01-01

    Purpose. We evaluated the suitability of Dacron, polytetrafluoroethylene (PTFE), and small intestinal submucosa (SIS) as a covering material for stent-grafts placed in the portal vein as compared with a bare stent. Methods. Using 24 beagle dogs, either bare stents or stent-grafts covered with Dacron, PTFE, or SIS were placed in the main trunk of the portal vein in 6 animals each. Portography was performed immediately after stent placement, and at 2, 4, and 12 weeks thereafter. Next, the extracted stents or stent-grafts were examined histopathologically. Neointimal thickness adjacent to the stent wire and at the midportion between the stent wires was compared among the groups. Then, the neointimal thickness at the sub- and supragraft sites was compared between each stent-graft group. Serial changes in the histologic features of the thickened neointima were also investigated. Results. No significant difference was noted in the mean stenotic ratio of the portal vein diameter between the bare stent and PTFE groups, whereas it was significantly higher in the Dacron and SIS groups compared with the bare stent group. In neither of the studies on neointimal thickness adjacent to the stent wire and at the midportion between the stent wires were any significant differences noted between the neointimal thickness of the bare stent group and the sum of the neointimal thickness of the PTFE group, whereas the sum of the neointimal thickness of the Dacron and SIS groups was significantly greater than that of the bare stent group at both sites. In the comparison of the supragraft neointimal thickness, the SIS group showed significantly greater thickness than the PTFE group, while the difference between the Dacron and PTFE groups was not significant. In the comparison of the subgraft neointimal thickness, the Dacron and SIS groups showed significantly greater thickness than the PTFE group. Conclusion. The present results indicate that of the three covering materials examined here

  11. 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

  12. Influence of covered stent versus bare stent on long-term efficacy of transjugular intrahepatic portosystemic shunt: a meta-analysis

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    XU Lu

    2016-10-01

    Full Text Available Objective To investigate the long-term postoperative efficacy of transjugular intrahepatic portosystemic shunt (TIPS using polytetrafluoroethylene (PTFE-covered stent or bare stent, and to provide a basis of evidence-based medicine for the selection of stent in TIPS. Methods CBM, Wanfang Data, CNKI, VIP, MEDLINE, and PubMed were searched for controlled trials on TIPS in the treatment of cirrhotic portal hypertension published form 1989 to 2015; the studies which met the inclusion criteria were selected, and quality assessment was performed for these articles. RevMan 5.3 software was used to analyze the incidence rates of stent dysfunction and hepatic encephalopathy and 1-year survival rate after TIPS, and funnel plots were used to analyze publication bias. Results A total of 11 studies were included, consisting of 698 patients in PTFE-covered stent group and 1283 patients in bare stent group. The results of the meta-analysis showed that the PTFE-covered stent group showed a significantly lower incidence rate of stent dysfunction than the bare stent group (14.8% vs 47.0%, OR=0.18, 95% CI: 0.13-0.24, P<0.001. There was no significant difference in the incidence rate of hepatic encephalopathy between the two groups (23.5% vs 25.7%, OR=0.88, 95% CI: 0.66-1.17, P=0.37. The PTFE-covered stent group had a significantly higher 1-year survival rate than the bare stent group (76.9% vs 62.7%, OR=2.10, 95% CI: 1.54-2.85, P<0.001. The funnel plots which were plotted based on the incidence rates of stent dysfunction and hepatic encephalopathy and 1-year survival rate lacked symmetry, which suggested that a certain degree of publication bias might exist. Conclusion Compared with the bare stent, the PTFE-covered stent can improve stent dysfunction and 1-year survival rate after TIPS, while there is no significant change in the incidence rate of hepatic encephalopathy. Therefore, the PTFE-covered stent has certain advantages over the bare stent in TIPS. In

  13. Treatment of carotid artery aneurysms with covered stents; Aneurysmabehandlung der Arteria carotis interna mit gecoverten Stents

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    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.)

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

    Science.gov (United States)

    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.

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

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    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.

  16. Late Migration of Two Covered Biliary Stents Through a Spontaneous Bilioenteric Fistula in a Patient with Malignant Biliary Obstruction

    International Nuclear Information System (INIS)

    Krokidis, Miltiadis E.; Hatzidakis, Adam A.; Manousaki, Eirini G.; Gourtsoyiannis, Nicholas C.

    2008-01-01

    We report a case of simultaneous late migration of two ePTFE-FEP covered biliary endoprostheses (Viabil, W.L. Gore, Flagstaff, AZ, USA) that were percutaneously implanted for the treatment of malignant obstructive jaundice. The first Viabil covered stent was placed successfully without any evidence of dislocation or other complication during follow-up. Occlusion of the stent occurred 4 months later and was treated with the placement of a second stent of the same type. Thirteen months later the patient became symptomatic. Percutaneous transhepatic cholangiography (PTC) revealed the presence of a choledocho-duodenal fistula and the disappearance of the two endoprostheses previously implanted. A third metallic stent was then percutaneously positioned through the bilioenteric fistula. The computed tomography scan that followed for the detection of the metallic bodies did not reveal the dislocated metallic stents. Stent migration is a well-known complication of uncovered metallic stents, though Viabil stent migration is assumed to be most unlikely to happen due to the stent's anchoring barbs. Furthermore, the stent had already been tightly fixed by tumor over- and ingrowth, as recognized in previous imaging. This is a very unusual case, describing the disappearance of two metallic foreign bodies encapsulated by tumor

  17. Usefulness of a balloon-expandable, covered stent for the transjugular intrahepatic portosystemic shunt

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    Rössle M

    2018-01-01

    Full Text Available The availability of polytetrafluoroethylene (PTFE covered, self-expandable nitinol stents in 2001 considerably improved the patency, response rates and survival of the transjugular intrahepatic portosystemic shunt (TIPS. Side effects of portosystemic shunting such as hepatic encephalopathy (HE and worsening of hepatic function, however, remained a problem. To reduce HE, underdilatation of nitinol stents has been practiced for many years. However, as shown recently, underdilatation was a flop since, due to their intrinsic memory, nitinol stents always expanded to reach their nominal diameter of 8 or 10 mm. To overcome this problem and to be able to perform permanent shunts with a smaller diameter of < 8 mm, we studied the usefulness of a balloon-expandable, covered, metallic stent which allowed adjustment to any diameter between 5 and 12 mm. Methods: 30 patients with cirrhosis and symptomatic portal hypertension were included. The mean Child-Pugh score was 8 ± 2.17 patients had refractory ascites, 9 patients variceal bleeding and four patients other indications for the TIPS. Results: The TIPS was successfully implanted in all patients within 69.6 ± 21.8 min. The shunt reduced the portosystemic pressure gradient by 57.5 ± 14.2% with a mean stent diameter of 7.4 ± 1.0 mm (5 -10.3 mm. During a mean follow-up of 330 ± 249 days, shunt revision was necessary in 5 patients (17%, four of them had insufficient response and received stent dilatation and one patient had stent misplacement requiring a parallel shunt. Three patients (10% developed HE. Conclusions: The covered, balloon-expandable stent could be placed accurately and allowed creation of adapted shunts with smaller diameters as usual. This resulted in a comparatively low rate of HE.

  18. Covered stent placement for the treatment of malignant superior vena cava syndrome: Is unilateral covered stenting and effective?

    International Nuclear Information System (INIS)

    Cho, Young Hoon; Gwon, Dong Il; Ko, Gi Young; Ko, Heung Kyu; Kim, Jin Hyoung; Shin, Ji Hoon; Yoon, Hyun Ki; Sung, Kyu Bo

    2014-01-01

    To evaluate the safety and efficacy of unilateral covered stent placement in patients with malignant superior vena cava (SVC) syndrome. Between October 2008 and November 2012, expanded polytetrafluoroethylene-covered stent placement for malignant SVC syndrome was performed in 40 consecutive patients (35 men and five women; mean age, 61.4 years; range, 35-81 years). All covered stents were unilaterally placed within the SVC or across the venous confluence when needed to relieve venous obstruction and prevent tumor overgrowth, regardless of patency of contralateral brachiocephalic veins. Stent placement was technically successful in all patients. There were no major complications. Of the 37 patients symptomatic prior to stent placement, 34 (92%) experienced complete symptomatic relief 1-8 days after stent placement. Of the 29 patients who underwent covered stent placement across the venous confluence, nine patients had patent contralateral brachiocephalic veins prior to stent placement. However, no sign of SVC obstruction or contralateral upper extremity venous thrombosis was observed during the follow-up period. Kaplan-Meier analysis revealed median patient survival of 163 days. Stent occlusion occurred in four (10%) of 40 patents. Cumulative stent patency rates at 1, 3, 6, and 12 months were 95%, 92%, 86%, and 86%, respectively. Unilateral covered stent placement appears to be a safe and effective method for treating malignant SVC syndrome, despite the location of SVC occlusion.

  19. Covered stent placement for the treatment of malignant superior vena cava syndrome: Is unilateral covered stenting and effective?

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young Hoon; Gwon, Dong Il; Ko, Gi Young; Ko, Heung Kyu; Kim, Jin Hyoung; Shin, Ji Hoon; Yoon, Hyun Ki; Sung, Kyu Bo [Dept. of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of)

    2014-02-15

    To evaluate the safety and efficacy of unilateral covered stent placement in patients with malignant superior vena cava (SVC) syndrome. Between October 2008 and November 2012, expanded polytetrafluoroethylene-covered stent placement for malignant SVC syndrome was performed in 40 consecutive patients (35 men and five women; mean age, 61.4 years; range, 35-81 years). All covered stents were unilaterally placed within the SVC or across the venous confluence when needed to relieve venous obstruction and prevent tumor overgrowth, regardless of patency of contralateral brachiocephalic veins. Stent placement was technically successful in all patients. There were no major complications. Of the 37 patients symptomatic prior to stent placement, 34 (92%) experienced complete symptomatic relief 1-8 days after stent placement. Of the 29 patients who underwent covered stent placement across the venous confluence, nine patients had patent contralateral brachiocephalic veins prior to stent placement. However, no sign of SVC obstruction or contralateral upper extremity venous thrombosis was observed during the follow-up period. Kaplan-Meier analysis revealed median patient survival of 163 days. Stent occlusion occurred in four (10%) of 40 patents. Cumulative stent patency rates at 1, 3, 6, and 12 months were 95%, 92%, 86%, and 86%, respectively. Unilateral covered stent placement appears to be a safe and effective method for treating malignant SVC syndrome, despite the location of SVC occlusion.

  20. Safety and Efficacy of Percutaneous Biliary Covered Stent Placement in Patients with Malignant Biliary Hilar Obstruction; Correlation with Liver Function

    Energy Technology Data Exchange (ETDEWEB)

    Hyun, Hyeran; Choi, Sun Young, E-mail: medmath@hanmail.net [School of Medicine Ewha Womans University, Department of Radiology and Medical Research Institute (Korea, Republic of); Kim, Kyung Ah [St. Vincent’s Hospital, The Catholic University of Korea, Department of Radiology (Korea, Republic of); Ko, Soo Bin [College of Arts and Science Case Western Reserve University, Department of Biology (United States)

    2016-09-15

    PurposeTo estimate the safety and efficacy of percutaneous ePTFE-covered biliary stent placement and the relationship between underlying liver function and stent patency in patients with malignant hilar obstruction.Materials and MethodsFrom March 2012 to June 2015, 41 patients [22 females, 19 males; mean age 69.8 (range 34–94) years] with malignant biliary obstruction underwent percutaneous biliary stent placement (31 patients with unilateral, 10 patients with bilateral side-by-side). Cumulative patient survival and stent patency rate curves were derived using the Kaplan–Meier method. A Cox model was used to explore the relationship between liver function and patient survival, and also biliary stent patency. Pearson correlation coefficient was used to analyze the relationship between patient survival and stent patency.ResultsTechnical success rate was 100 % and clinical success rate was 95 %. During follow-up, four complications occurred (two bilomas and two cases of acute cholecystitis) and were treated successfully with percutaneous drainage. No other complication occurred. Mean serum bilirubin level was 11.34 ± 7.35 mg/dL before drainage and 5.00 ± 4.83 mg/dL 2 weeks after stent placement. The median patent survival duration was 147 days (95 % CI, 69.6–224.4 days). The median stent patency duration was 101 days (95 % CI, 70.0–132.0 days). The cumulative stent patency rates at 1, 3, 6, and 12 months were 97, 57.6, 30.3, and 17.0 %, respectively. Child–Pugh score was correlated significantly with patient survival (P = 0.011) and stent patency (P = 0.007). MELD score was correlated significantly with stent patency (P = 0.044). There was a correlation between patient survival and stent patency (r = 0.778, P < 0.001).ConclusionPercutaneous placement of ePTFE-covered biliary stent was a safe and an effective method for malignant biliary obstruction. Underlying liver function seemed to be one of the important factors affecting

  1. Safety and Efficacy of Percutaneous Biliary Covered Stent Placement in Patients with Malignant Biliary Hilar Obstruction; Correlation with Liver Function

    International Nuclear Information System (INIS)

    Hyun, Hyeran; Choi, Sun Young; Kim, Kyung Ah; Ko, Soo Bin

    2016-01-01

    PurposeTo estimate the safety and efficacy of percutaneous ePTFE-covered biliary stent placement and the relationship between underlying liver function and stent patency in patients with malignant hilar obstruction.Materials and MethodsFrom March 2012 to June 2015, 41 patients [22 females, 19 males; mean age 69.8 (range 34–94) years] with malignant biliary obstruction underwent percutaneous biliary stent placement (31 patients with unilateral, 10 patients with bilateral side-by-side). Cumulative patient survival and stent patency rate curves were derived using the Kaplan–Meier method. A Cox model was used to explore the relationship between liver function and patient survival, and also biliary stent patency. Pearson correlation coefficient was used to analyze the relationship between patient survival and stent patency.ResultsTechnical success rate was 100 % and clinical success rate was 95 %. During follow-up, four complications occurred (two bilomas and two cases of acute cholecystitis) and were treated successfully with percutaneous drainage. No other complication occurred. Mean serum bilirubin level was 11.34 ± 7.35 mg/dL before drainage and 5.00 ± 4.83 mg/dL 2 weeks after stent placement. The median patent survival duration was 147 days (95 % CI, 69.6–224.4 days). The median stent patency duration was 101 days (95 % CI, 70.0–132.0 days). The cumulative stent patency rates at 1, 3, 6, and 12 months were 97, 57.6, 30.3, and 17.0 %, respectively. Child–Pugh score was correlated significantly with patient survival (P = 0.011) and stent patency (P = 0.007). MELD score was correlated significantly with stent patency (P = 0.044). There was a correlation between patient survival and stent patency (r = 0.778, P < 0.001).ConclusionPercutaneous placement of ePTFE-covered biliary stent was a safe and an effective method for malignant biliary obstruction. Underlying liver function seemed to be one of the important factors affecting

  2. 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

  3. Usefulness of flexible covered stent in malignant colorectal obstruction

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Jee Hee; Kang, Sung Gwon; Kim, Hyung Jin; Noh, Hong Gi; Woo, Jae Hong; Suh, Chang Hae [Inha Univ. Hospital, Inchon (Korea, Republic of)

    1998-07-01

    To evaluate the usefulness of flexible covered stent in the treatment of acute colorectal obstruction secondary to colorectal carcinoma. Materials and Methods : Flexible covered stents were placed in 11 patients with clinical and radiologic signs of acute colonic obstruction secondary to colorectal carcinoma. The purposes of stent insertion were pre-operative bowel preparation in seven patients and palliative treatment in four. A fistula was present in two;in one this was between the proximal jejunum and colon, and the other was rectovaginal. The usefulness of stent insertion for the purpose of preoperative bowel preparation was evaluated according to the feasibility and status of bowel preparation, as decided by the operator. Palliative treatment for the relief of symptoms of acute bowel obstruction was evaluated according to the number and amount of defecation,bowel dilatation in simple abdomen radiography, and the presence of complications. Results : Bowel preparation for the purpose of preoperative bowel cleansing was easy in seven patients;the fecal materials remaining in the colon presented no problems during surgery. In one of four patients palliative treatment involved a colostomy;this was due to recurrent stent obstruction by fecal materials after three months, and in two other patients there was stent obstruction after two and five months, respectively. The stent in one of four patients who underwent palliative treatment was removed because of stent migration three days after insertion;the stents in two patients with fistulas covered the fistulas successfully. Complications after stent insertion were anal pain in three patients, anal bleeding in three and stent migration in one. Conclusion : The flexible covered stent was an effective device for the relief of acute colonic obstruction secondary to malignant rectosigmoid neoplasia. It allowed for single-stage operation and covered the fistula. We believe however that for further evaluation of the

  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. 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.

  6. Treatment of esophagopleural fistulas using covered retrievable expandable metallic stents.

    Science.gov (United States)

    Kim, Tae-Hyung; Shin, Ji Hoon; Kim, Kyung Rae; Park, Jung-Hoon; Kim, Jin Hyoung; Song, Ho-Young

    2014-04-01

    To evaluate the clinical efficacy of placement of covered retrievable expandable metallic stents for esophagopleural fistulas (EPFs). During the period 1997-2013, nine patients with EPF were treated using covered retrievable expandable metallic stents. The underlying causes of EPF were esophageal carcinoma (n = 6), lung cancer (n = 2), and postoperative empyema for Boerhaave syndrome (n = 1). Technical success was achieved in eight patients (88.9%). In one patient, incomplete EPF closure was due to incomplete stent expansion. Clinical success, defined as complete EPF closure within 7 days, was achieved in five patients (55.6%). Overall fistula persistence (n = 1) or reopening (n = 4) occurred in five patients (55.6%) 0-15 days after stent placement. The causes of reopening were due to the gap between the stent and the esophagus (n = 3) or stent migration (n = 1). For fistula persistence or reopening, additional interventional management, such as gastrostomy, stent removal, or stent reinsertion, was performed. Stent migration occurred as a complication in one patient with EPF from a benign cause secondary to postoperative empyema. In the eight patients who died during the follow-up period, the mean and median survival times were 78.8 days and 46 days, respectively. Placement of a covered expandable metallic esophageal stent for the palliative treatment of EPF is technically feasible, although the rate of clinical success was poor secondary to fistula persistence or reopening. Fistula reopening was caused by the gap between the stent and the esophagus or by stent migration, and additional interventional treatment was useful to ensure enteral nutritional support. Copyright © 2014 SIR. Published by Elsevier Inc. All rights reserved.

  7. Therapeutic evaluation of retrievable esophageal covered stent in treating achalasia

    International Nuclear Information System (INIS)

    Li Yuwei; Zhang Fuqiang; Yuan Liang; Li Yunhui; Luo Bin; Yu Li; Sun Dingqiang

    2010-01-01

    Objective: To evaluate the clinical effect of retrievable esophageal covered metal internal stent in treating patients with achalasia. Methods: Under DSA guidance, peroral 'Z-type' double horn covered metal internal stent implantation was performed in 16 patients with achalasia. Esophagography was carried out about 28 days after the procedure and the stent was retrieved. Results: Of 16 cases, the stent fell off into the stomach two weeks after the operation in one. And the stent was successfully replaced after it was taken out. The placed stent was successfully retrieved in all cases 28 days after the treatment. No serious complications occurred. All the patients were followed up for 3 months to 3 years. During the follow-up period restenosis of the esophagus developed in two cases (at one and 1.5 years respectively), and the restenosis degree was relived after balloon dilation. Clinically, no esophageal symptoms, such as dysphagia, occurred in all patients. Conclusion: As a simple and safe technique, the retrievable esophageal covered metal internal stent implantation is very effective with fewer complications for the treatment of achalasia. Moreover, the technique carries lower restenosis occurrence. (authors)

  8. Experimental research of covered stent implanted in canine hepatic artery

    International Nuclear Information System (INIS)

    Zhou Bing; Liu Linxiang; Li Minghua; Wang Yongli; Cheng Yongde

    2007-01-01

    Objective: To evaluate the feasibility of success rate of implantation, post-procedure stenosis rate, apposition ability and endothelialization level, etc. for implantation with balloon-expandable covered stent in canine hepatic artery. Methods: 8 adult canines were implanted with balloon-expendable stents covered by expandable poly Teflon ester membrane (e-PTFEM). Follow-up DSA was performed immediately, 2, 4 and 12 wk after the procedure. The canines were sacrificed for histopathologic examination and statistical analysis with correlation of implantation manenvor and angiographic manifestations. Results: 8 cases were all implanted with the covered stents in proper hepatic artery/right hepatic artery successfully; showing good apposition ability and non-opacification of the separated branches. 2 cases showed intraluminal obvious stenosis( > 50%)of the stent at 2 weeks follow-up, so did 3 cases at 12 weeks follow-up, and the total stenosis rate was 37.5% and 5 cases manifested full endothelialization (3 different locations of the sample all manifested full endothelialization), 3 cased manifested partial endothelialization (at least 1 location of the sample didn't show full endothelialization), and the two terminal parts were easier to get endothelialization than the central part. Before and after the stent implantation, hepatic function of all cases didn't demonstrate any obvious changes. Conclusions: Balloon-expandable covered stent can be implanted in canine hepatic artery. successfully, with good apposition ability, full endothelialization, and no influence on hepatic function. (authors)

  9. Covered stent to exclude intravascular thrombus.

    Science.gov (United States)

    Liistro, Francesco; Stankovic, Goran; Di Mario, Carlo; Montorfano, Matteo; Briguori, Carlo; Colombo, Antonio

    2002-04-01

    To describe the utility of stent-graft implantation to avoid distal embolization from a large thrombus-containing lesion. A 67-year-old man was evaluated for recent onset of disabling left leg claudication. Angiography disclosed a mobile lobular mass occluding the left common iliac artery; irregular staining suggested an atherothrombotic lesion. Through a percutaneous ipsilateral access and an 8-F sheath, a balloon-expandable Jostent peripheral stent-graft was positioned with the distal edge immediately proximal to the internal iliac artery ostium. A prominent "waist" at the center of the balloon confirmed entrapment of the thrombotic mass. Completion angiography showed an optimal result with no residual stenosis or evidence of distal embolization. At 6-month follow-up, the patient was asymptomatic with angiographically documented luminal patency and no evidence of in-stent stenosis. Stent-graft implantation appears a viable treatment alternative for thrombus-containing lesions, particularly when the thrombotic material is localized or is in a large vessel.

  10. Intraluminal Radioactive Stent Compared with Covered Stent Alone for the Treatment of Malignant Esophageal Stricture

    International Nuclear Information System (INIS)

    Wang Zhongmin; Huang Xunbo; Cao Jun; Huang Gang; Chen Kemin; LIu Yu; Liu Fenju

    2012-01-01

    Objective: This study was designed to compare the clinical effectiveness of intraluminal radioactive stent loaded with iodine-125 seeds implantation versus covered stent alone insertion in patients with malignant esophageal stricture. Methods: We studied two groups of patients with malignant esophageal stricture. Group A comprised 28 patients (19 men and 9 women) who underwent intraluminal radioactive stent loaded with iodine-125 seeds implantation and were followed prospectively. Group B comprised 30 patients (18 men and 12 women) who had previously received covered stent alone insertion; these patients were evaluated retrospectively. There was no crossover between the two groups during follow-up. Informed consent was obtained from each patient, and our institutional review board approved the study. The dysphagia score, overall survival rates, complication rates, and reintervention rates were compared in the two groups. Results: There were no significant differences between the two groups in terms of baseline characteristics. Stent placement was technically successful and well tolerated in all patients. The dysphagia score was improved in both groups after stent placement. The median survival was significantly longer in group A than in group B: 11 versus 4.9 months, respectively (P < 0.001). The complications of chest pain, esophageal reflux, and stent migration was more frequent in group B, but this difference did not reach statistical significance. There was no statistical difference in reintervention between two groups. Conclusions: Intraluminal radioactive stent loaded with iodine-125 seeds implantation was a feasible and practical management in treating malignant esophageal stricture and was superior to covered stent alone insertion, as measured by survival.

  11. Esophagorespiratory fistula: treatment with self-expanding covered stent

    International Nuclear Information System (INIS)

    Zang Jian; Dou Yongchong; Wang Zheng; Kong Jian

    2002-01-01

    Objective: To evaluate self-expanding covered stent in the management of esophagorespiratory fistula. Methods: A self-expanding esophageal covered stent was implanted under fluoroscopic guidance in 13 patients with esophagorespiratory fistula. In this series patients aged 31-73 years (60.2 years in average). All patients had a pre-procedure fast of 6-41 days (17.3 days in average), in which 12 patients had pulmonary infection. Results: All fistulas were excluded and swallowing function was restored. No stend-related complication was observed. Pulmonary infection was managed in 10 patients out of 13. The mean survived time was 33.3 wks (1-178 wks) in follow-up. Conclusion: Covered self-expanding stent implantation is a safe and effective treatment of ERF

  12. Partially Covered Metal Stents May Not Prolong Stent Patency Compared to Uncovered Stents in Unresectable Malignant Distal Biliary Obstruction

    Science.gov (United States)

    Kim, Jae Yun; Ko, Gyu Bong; Lee, Tae Hoon; Park, Sang-Heum; Lee, Yun Nah; Cho, Young Sin; Jung, Yunho; Chung, Il-Kwun; Choi, Hyun Jong; Cha, Sang-Woo; Moon, Jong Ho; Cho, Young Deok; Kim, Sun-Joo

    2017-01-01

    Background/Aims Controversy still exists regarding the benefits of covered self-expandable metal stents (SEMSs) compared to uncovered SEMSs. We aimed to compare the patency and stent-related adverse events of partially covered SEMSs (PC-SEMSs) and uncovered SEMSs in unresectable malignant distal biliary obstruction. Methods A total of 134 patients who received a PC-SEMS or uncovered SEMS for palliation of unresectable malignant distal biliary obstruction were reviewed retrospectively. The main outcome measures were stent patency, stent-related adverse events, and overall survival. Results The median stent patency was 118 days (range, 3 to 802 days) with PC-SEMSs and 105 days (range, 2 to 485 days) with uncovered SEMSs (p=0.718). The overall endoscopic revision rate due to stent dysfunction was 36.6% (26/71) with PC-SEMSs and 36.5% (23/63) with uncovered SEMSs (p=0.589). Tumor ingrowth was more frequent with uncovered SEMSs (4.2% vs 19.1%, p=0.013), but migration was more frequent with PC-SEMSs (11.2% vs 1.5%, p=0.04). The incidence of stent-related adverse events was 2.8% (2/71) with PC-SEMSs and 9.5% (6/63) with uncovered SEMSs (p=0.224). The median overall survival was 166 days with PC-SEMSs and 168 days with uncovered SEMSs (p=0.189). Conclusions Compared to uncovered SEMSs, PC-SEMSs did not prolong stent patency in unresectable malignant distal biliary obstruction. Stent migration was more frequent with PC-SEMSs. However, tumor ingrowth was less frequent with PC-SEMSs compared to uncovered SEMSs. PMID:28208003

  13. 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).

  14. Comparison between uncovered and covered self-expandable metal stent placement in malignant duodenal obstruction.

    Science.gov (United States)

    Kim, Ji Won; Jeong, Ji Bong; Lee, Kook Lae; Kim, Byeong Gwan; Ahn, Dong Won; Lee, Jae Kyung; Kim, Su Hwan

    2015-02-07

    To compare the clinical outcomes of uncovered and covered self-expandable metal stent placements in patients with malignant duodenal obstruction. A total of 67 patients were retrospectively enrolled from January 2003 to June 2013. All patients had symptomatic obstruction characterized by nausea, vomiting, reduced oral intake, and weight loss. The exclusion criteria included asymptomatic duodenal obstruction, perforation or peritonitis, concomitant small bowel obstruction, or duodenal obstruction caused by benign strictures. The technical and clinical success rate, complication rate, and stent patency were compared according to the placement of uncovered (n = 38) or covered (n = 29) stents. The technical and clinical success rates did not differ between the uncovered and covered stent groups (100% vs 96.6% and 89.5% vs 82.8%). There were no differences in the overall complication rates between the uncovered and covered stent groups (31.6% vs 41.4%). However, stent migration occurred more frequently with covered than uncovered stents [20.7% (6/29) vs 0% (0/38), P stent patency was longer in uncovered than in covered stents [251 d (95%CI: 149.8 d-352.2 d) vs 139 d (95%CI: 45.5 d-232.5 d), P stent (70 d) and covered stent groups (60 d). Uncovered stents may be preferable in malignant duodenal obstruction because of their greater resistance to stent migration and longer stent patency than covered stents.

  15. Covered duodenal self-expandable metal stents prolong biliary stent patency in double stenting: The largest series of bilioduodenal obstruction.

    Science.gov (United States)

    Hori, Yasuki; Naitoh, Itaru; Hayashi, Kazuki; Kondo, Hiromu; Yoshida, Michihiro; Shimizu, Shuya; Hirano, Atsuyuki; Okumura, Fumihiro; Ando, Tomoaki; Jinno, Naruomi; Takada, Hiroki; Togawa, Shozo; Joh, Takashi

    2018-03-01

    Endoscopic biliary and duodenal stenting (DS; double stenting) is widely accepted as a palliation therapy for malignant bilioduodenal obstruction. The aim of the current study was to investigate the patency and adverse events of duodenal and biliary stents in patients with DS. Patients who underwent DS from April 2004 to March 2017 were analyzed retrospectively with regard to clinical outcomes and predictive factors of recurrent biliary and duodenal obstruction (recurrent biliary obstruction [RBO] and recurrent duodenal obstruction [RDO]). A total of 109 consecutive patients was enrolled. Technical success of DS was achieved in 108 patients (99.1%). Symptoms due to biliary and duodenal obstruction were improved in 89 patients (81.7%). RBO occurred in 25 patients (22.9%) and RDO in 13 (11.9%). The median times to RBO and RDO from DS were 87 and 76 days, respectively. Placement of a duodenal uncovered self-expandable metal stent (U-SEMS) was significantly associated with RBO in the multivariable analysis (P = 0.007). Time to RBO was significantly longer in the duodenal covered self-expandable metal stent group than in the U-SEMS group (P = 0.003). No predictive factors of RDO were detected, and duodenal stent type was not associated with the time to RDO (P = 0.724). Double stenting was safe and effective for malignant bilioduodenal obstruction. Duodenal U-SEMS is a risk factor for RBO. The covered self-expandable metal stent is the preferred type of duodenal SEMS in patients with DS (Clinical trial registration number: UMIN000027606). © 2017 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.

  16. Effect of Covered Metallic Stents Compared With Plastic Stents on Benign Biliary Stricture Resolution

    Science.gov (United States)

    Coté, Gregory A.; Slivka, Adam; Tarnasky, Paul; Mullady, Daniel K.; Elmunzer, B. Joseph; Elta, Grace; Fogel, Evan; Lehman, Glen; McHenry, Lee; Romagnuolo, Joseph; Menon, Shyam; Siddiqui, Uzma D.; Watkins, James; Lynch, Sheryl; Denski, Cheryl; Xu, Huiping; Sherman, Stuart

    2017-01-01

    IMPORTANCE Endoscopic placement of multiple plastic stents in parallel is the first-line treatment for most benign biliary strictures; it is possible that fully covered, self-expandable metallic stents (cSEMS) may require fewer endoscopic retrograde cholangiopancreatography procedures (ERCPs) to achieve resolution. OBJECTIVE To assess whether use of cSEMS is noninferior to plastic stents with respect to stricture resolution. DESIGN, SETTING, AND PARTICIPANTS Multicenter (8 endoscopic referral centers), open-label, parallel, randomized clinical trial involving patients with treatment-naive, benign biliary strictures (N = 112) due to orthotopic liver transplant (n = 73), chronic pancreatitis (n = 35), or postoperative injury (n = 4), who were enrolled between April 2011 and September 2014 (with follow-up ending October 2015). Patients with a bile duct diameter less than 6 mm and those with an intact gallbladder in whom the cystic duct would be overlapped by a cSEMS were excluded. INTERVENTIONS Patients (N = 112) were randomized to receive multiple plastic stents or a single cSEMS, stratified by stricture etiology and with endoscopic reassessment for resolution every 3 months (plastic stents) or every 6 months (cSEMS). Patients were followed up for 12 months after stricture resolution to assess for recurrence. MAIN OUTCOMES AND MEASURES Primary outcome was stricture resolution after no more than 12 months of endoscopic therapy. The sample size was estimated based on the noninferiority of cSEMS to plastic stents, with a noninferiority margin of −15%. RESULTS There were 55 patients in the plastic stent group (mean [SD] age, 57 [11] years; 17 women [31%]) and 57 patients in the cSEMS group (mean [SD] age, 55 [10] years; 19 women [33%]). Compared with plastic stents (41/48, 85.4%), the cSEMS resolution rate was 50 of 54 patients (92.6%), with a rate difference of 7.2% (1-sided 95% CI, −3.0% to ∞; P stents was rejected. The mean number of ERCPs to achieve resolution

  17. Fully covered stents versus partially covered stents for palliative treatment of esophageal cancer: Is there a difference?

    Science.gov (United States)

    Alonso Lárraga, J O; Flores Carmona, D Y; Hernández Guerrero, A; Ramírez Solís, M E; de la Mora Levy, J G; Sánchez Del Monte, J C

    2018-02-26

    Malignant dysphagia is difficulty swallowing resulting from esophageal obstruction due to cancer. The goal of palliative treatment is to reduce the dysphagia and improve oral dietary intake. Self-expandable metallic stents are the current treatment of choice, given that they enable the immediate restoration of oral intake. The aim of the present study was to describe the results of using totally covered and partially covered esophageal stents for palliating esophageal cancer. A retrospective study was conducted on patients with inoperable esophageal cancer treated with self-expandable metallic stents. The 2 groups formed were: group A, which consisted of patients with a fully covered self-expandable stent (SX-ELLA ® ), and group B, which was made up of patients with a partially covered self-expandable stent (Ultraflex ® ). Of the 69-patient total, 50 were included in the study. Group A had 19 men and 2 women and their mean age was 63.6 years (range 41-84). Technical success was achieved in 100% (n=21) of the cases and clinical success in 90.4% (n=19). Group B had 24 men and 5 women and their mean age was 67.5 years (range 43-92). Technical success was achieved in 100% (n=29) of the cases and clinical success in 89.6% (n=26). Complications were similar in both groups (33.3 vs. 51.7%). There was no difference between the 2 types of stent for the palliative treatment of esophageal cancer with respect to technical success, clinical success, or complications. Copyright © 2018 Asociación Mexicana de Gastroenterología. Publicado por Masson Doyma México S.A. All rights reserved.

  18. Fully covered self-expandable metal stents (SEMS), partially covered SEMS and self-expandable plastic stents for the treatment of benign esophageal ruptures and anastomotic leaks.

    Science.gov (United States)

    van Boeckel, Petra G A; Dua, Kulwinder S; Weusten, Bas L A M; Schmits, Ruben J H; Surapaneni, Naveen; Timmer, Robin; Vleggaar, Frank P; Siersema, Peter D

    2012-02-29

    Benign esophageal ruptures and anastomotic leaks are life-threatening conditions that are often treated surgically. Recently, placement of partially and fully covered metal or plastic stents has emerged as a minimally invasive treatment option. We aimed to determine the clinical effectiveness of covered stent placement for the treatment of esophageal ruptures and anastomotic leaks with special emphasis on different stent designs. Consecutive patients who underwent placement of a fully covered self-expandable metal stent (FSEMS), a partially covered SEMS (PSEMS) or a self-expanding plastic stent (SEPS) for a benign esophageal rupture or anastomotic leak after upper gastrointestinal surgery in the period 2007-2010 were included. Data on patient demographics, type of lesion, stent placement and removal, clinical success and complications were collected A total of 52 patients received 83 esophageal stents (61 PSEMS, 15 FSEMS, 7 SEPS) for an anastomotic leak (n=32), iatrogenic rupture (n=13), Boerhaave's syndrome (n=4) or other cause (n=3). Endoscopic stent removal was successful in all but eight patients treated with a PSEMS due to tissue ingrowth. Clinical success was achieved in 34 (76%, intention-to-treat: 65%) patients (PSEMS: 73%, FSEMS: 83%, SEPS: 83%) after a median of 1 (range 1-5) stent and a median stenting time of 39 (range 7-120) days. In total, 33 complications in 24 (46%) patients occurred (tissue in- or overgrowth (n=8), stent migration (n=10), ruptured stent cover (all Ultraflex; n=6), food obstruction (n=3), severe pain (n=2), esophageal rupture (n=2), hemorrhage (n=2)). One (2%) patient died of a stent-related cause. Covered stents placed for a period of 5-6 weeks may well be an alternative to surgery for treating benign esophageal ruptures or anastomotic leaks. As efficacy between PSEMS, FSEMS and SEPS is not different, stent choice should depend on expected risks of stent migration (SEPS and FSEMS) and tissue in- or overgrowth (PSEMS).

  19. A comparison of clinical efficacy between covered stent-grafts and bare stents in transjuglar in-trahepatic portosystemic shunt

    International Nuclear Information System (INIS)

    Jiang Yongbin; Zhang Xitong; Zhang Wei; Xia Yonghui; Liang Songnian; Xu Ke

    2010-01-01

    Objective: To compare the clinical efficacy between covered stent and uncovered stent in transjuglar in-trahepatic portosystemic shunt (TIPS). Methods: Thirty patients with liver cirrhosis (portal hypertension), who received TIPS, were retrospectively studied. All patients were divided into two groups covered-stent group (n=20) and uncovered-stent group (n=10). For each patient, portal pressure was measured before and after operation, and the patency of shunt was evaluated by color Doppler ultrasound after operation. The mortality, recurrent bleeding rate and incidence of hepatic encephalopathy were analyzed by Fisher exact probability test. Results: The TIPS treatment was successful in all patients, the portal pressure in the covered-stent group reduced from (3.78 ± 0.50)kPa to (2.13 ± 0.44) kPa and that of the uncovered-stent group reduced from (3.67 ± 0.48)kPA TO (2.13 ± 0.35)kPa. Twenty-six cases were postoperatively followed-up (17 cases in covered-stent group, 9 cases in uncovered-stent group). the follow-up period varied from 7 days to 62 months (median follow-up period was 23 months). Thirteen patients died of upper gastrointestinal bleeding and hepatic failure. The difference of mortality between covered-stent group (8/17) and uncovered-stent group (5/17) and the uncovered-stent group (3/9) was not different too (P>0.05). The incidence of hepatic encephalopathy in the covered-stent group (4/17) was not different from that of the uncovered-stent group (2/9) (P>0.05). The patency rates of 6 months and 12 months reached 100% in the covered-stent group, which were higher than those in the uncovered-stent group 77.8% (7/9) and 55.6%(5/9) (P<0.05). Conclusions: The patency rate of shunt at 12 months after TIPS was higher in the covered-stent group than the uncovered-stent group, while the mortality, recurrent bleeding rate and incidence of hepatic encephalopathy were not significantly different between the two groups. (authors)

  20. A Flexible Stent with Small Intestinal Submucosa Covering for Direct Intrahepatic Portocaval Shunt: Experimental Pilot Study in Swine

    International Nuclear Information System (INIS)

    Niyyati, Mahtab; Petersen, Bryan D.; Pavcnik, Dusan; Uchida, Barry T.; Timmermans, Hans A.; Hiraki, Takao; Wu Renghong; Brountzos, Elias; Keller, Frederick S.; Roesch, Josef

    2005-01-01

    The suitability of the flexible sandwich Zilver stent-graft (SZSG) with a biologically active tissue layer (small intestinal submucosa) for creation of the intravascular ultrasound (IVUS)-guided direct intrahepatic portocaval shunt (DIPS) was explored in six young swine in a search for a flexible system to replace the rigid polytetrafluoroethylene (PTFE) stent originally used by this group with limited success. The portal vein was punctured from the inferior vena cava through the caudate lobe of the liver using IVUS guidance. After balloon dilation of the puncture tract, DIPS was successfully created in all animals with use of an SZSG 9 mm in diameter and 6 cm or 8 cm long. Only one DIPS remained well patent at 14 days when the animal had to be killed because of encephalopathy. DIPS in the other five animals were found to be either severely stenosed (3 animals) or occluded (2 animals) at 4 weeks due to accelerated formation of neointimal hyperplasia (NIH) in the liver parenchymal portion of the shunt and superimposed thrombosis. The lack of high pressure in the portal system contributed to early endograft closure. The flexible stent and the covering fail badly. The reason for this could be due to either component. More work is required to find a reliable flexible system with long-term patency. Exploration of the IVUS-guided direct extrahepatic portocaval shunt is suggested

  1. [Complications and the management of fully covered retrievable metal stent placement in benign tracheal stenosis].

    Science.gov (United States)

    Wang, Zheng-yu; Wang, Yong-li; Chen, Guang-li; Liang, Xi-hong; Wang, Zhen-chang; Ma, Jian-zhong; Wu, Guang-zhong; Zhang, Xiao-ping

    2012-11-01

    To study complications and the management of the use of covered retrievable expandable metallic stents in the treatment of benign tracheal stenosis. Fully covered retrievable metal stents were placed in 21 patients with benign tracheal stenosis. Stent-related complications and the management were reviewed and analysed. Twenty-eight fully covered retrievable metallic stents were successfully placed fluoroscopically in 21 patients. Stents were removed 4 - 12 months [mean (5.5 ± 2.2) mouths] after placement in all patients. Stent-related complications included granulation tissue (n = 18), stent migration (n = 4), stent expectoration (n = 2), halitosis (n = 8), mucous retention (n = 21) and mucus plugging (n = 1). Granulation tissue was removed with a carbon dioxide laser in 2 patients. Stents were replaced for 2 times and 3 times respectively in 2 patients after stent migration and stent expectoration. An additional stent was placed in 2 patients after stent migration. Symptom of halitosis was relieved after prolonged course of systemic antibiotics treatment in 8 patients. Symptom of mucous retention was relieved with nebulized saline and N-acetylcysteine saline inhalation. Mucous plug was expelled after severe coughing after suctioning using an aspirator in one patient. There were statistically significant differences in stricture diameter, rank of tachypnea and pulmonary function (FEV(1)) in all 21 patients before stent insertion and after stents removal. No patient has experienced recurrence during the follow-up period of 1 - 36 months [mean (23.2 ± 8.0) months]. Fully covered retrievable metallic stent may be a safe and effective in benign tracheal stenosis. Stent-related complications may be effectively managed.

  2. Successful Exclusion of a Large Femoropopliteal Aneurysm with a Covered Nitinol Stent

    International Nuclear Information System (INIS)

    Dorffner, Roland; Winkelbauer, Friedrich; Kettenbach, Joachim; Staudacher, Michael; Lammer, Johannes

    1996-01-01

    A 70-year-old woman presented with a large femoropopliteal aneurysm. A covered nitinol stent was implanted successfully and complete exclusion of the aneurysm was achieved. At follow-up 5 months later the stent was still patent and the patient was free of symptoms. However, moderate stenosis was seen at the proximal end of the stent

  3. Evaluation of the Effects of Temporary Covered Nitinol Stent Placement in the Prostatic Urethra: Short-Term Study in the Canine Model

    International Nuclear Information System (INIS)

    Crisostomo, Veronica; Song, Ho Young; Maynar, Manuel; Sun, Fei; Soria, Federico; Lima, Juan Rafael; Yoon, Chang Jin; Uson-Gargallo, Jesus

    2007-01-01

    Purpose. To evaluate the effect of temporary stent placement on the canine prostatic urethra. Methods. Retrievable PTFE-covered nitinol stents were placed in the prostatic urethras of 8 beagle dogs under fluoroscopic guidance. Retrograde urethrography was obtained before and after stenting. Retrograde urethrography and endoscopy were performed 1 and 2 months after deployment. The endoscopic degree of hyperplasia was rated on a scale of 0 to 4 (0 absence, 4 = occlusion). On day 60, stents were removed and urethrography was performed immediately before euthanasia. Pathologic analysis was performed to determine the degree of glandular atrophy, periurethral fibrosis, and urethral dilation. Results. Stent deployment was technically successful in 7 animals, and failed in 1 dog due to a narrow urethral lumen. Complete migration was seen in 2 animals at 1 month, and an additional stent was deployed. On day 30, endoscopy showed slight hyperplasia (grade 1) in 3 animals. On day 60, moderate hyperplasia (grade 2) was evidenced in 4 cases. No impairment of urinary flow was seen during follow-up. Retrieval was technically easy to perform, and was successful in all dogs. The major histologic findings were chronic inflammatory cell infiltrates; prostate glandular atrophy, with a mean value of 1.86 (SD 0.90); periurethral fibrosis, with a mean ratio of 29.37 (SD 10.41); and dilatation of the prostatic urethra, with a mean ratio of 6.75 (SD 3.22). Conclusion. Temporary prostatic stent placement in dogs is safe and feasible, causing marked enlargement of the prostatic urethral lumen. Retrievable covered stents may therefore be an option for bladder outlet obstruction management in men

  4. Covered metal stent or multiple plastic stents for refractory pancreatic ductal strictures in chronic pancreatitis: a systematic review.

    Science.gov (United States)

    Shen, Yonghua; Liu, Mingdong; Chen, Min; Li, Yunhong; Lu, Ying; Zou, Xiaoping

    2014-01-01

    Refractory chronic pancreatitis has been proposed as a challenge for endoscopists following routine single plastic stenting. However, data on the efficacy and safety of further endoscopic stenting are still controversial. The current systematic review aimed to assess the efficacy and safety of placement of fully covered self-expandable metal stent (FCSEMS) and multiple plastic stents. Databases including MEDLINE, EMBASE, the Cochrane Library, CBM, CNKI, VIP, and WANFANG Database were used to search relevant trials. Published studies were assessed by using well-defined inclusion and exclusion criteria. The process was independently performed by two investigators. A total of 5 studies provided data of 80 patients. Forest plots and publication bias were not carried out because few studies were relevant and screened studies were all case series. The technical success rate was 100% both in placement of FCSEMS and multiple plastic stents. The functional success rate after placement of FCSEMS was 100%, followed by multiple plastic stents (94.7%). Complications occurred 26.2% after FCSEMS placement, which was not described in detail in multiple plastic stents. The stent migration rate was 8.2% for FCSEMS and 10.5% for multiple plastic stents. Reintervention rate was 9.8% for FCSEMS and 15.8% for multiple plastic stents. Pain improvement rate was 85.2% for FCSEMS and 84.2% for multiple plastic stents. FCSEMS appeared to be no significant difference with multiple plastic stents in treatment of refractory chronic pancreatitis. We need to develop more investigations. Copyright © 2014 IAP and EPC. Published by Elsevier B.V. All rights reserved.

  5. Assessment of a Polyester-Covered Nitinol Stent in the Canine Aorta and Iliac Arteries

    International Nuclear Information System (INIS)

    Castaneda, Flavio; Ball-Kell, Susan M.; Young, Kate; Li Ruizong

    2000-01-01

    Purpose: To evaluate the patency and healing characteristics of a woven polyester fabric-covered stent in the canine model.Methods: Twenty-four self-expanding covered stents were placed in the infrarenal aorta and bilateral common iliac arteries of eight dogs and evaluated at 1 (n = 2), 3 (n = 2), and 6 (n = 4) months. Stent assessment was done using angiography prior to euthanasia, and light and scanning electron microscopy.Results: Angiographically, just prior to euthanasia, 8 of 8 aortic and 14 of 16 iliac endovascular covered stents were patent. Histologically, the stented regions showed complete endothelialization 6 months after graft implantation. A neointima had formed inside the stented vessel regions resulting in complete encasement of the fabric-covered stent by 3 months after graft implantation. Medial compression with smooth muscle cell atrophy was present in all stented regions. Explanted stent wires, examined by scanning electron microscopy, showed pitting but no cracks or breakage.Conclusion: The covered stent demonstrated predictable healing and is effective in preventing stenosis in vessels 10.0 mm or greater in diameter but does not completely preclude stenosis in vessels 6.0 mm or less in diameter

  6. Evaluation of anti-migration properties of biliary covered self-expandable metal stents.

    Science.gov (United States)

    Minaga, Kosuke; Kitano, Masayuki; Imai, Hajime; Harwani, Yogesh; Yamao, Kentaro; Kamata, Ken; Miyata, Takeshi; Omoto, Shunsuke; Kadosaka, Kumpei; Sakurai, Toshiharu; Nishida, Naoshi; Kudo, Masatoshi

    2016-08-14

    To assess anti-migration potential of six biliary covered self-expandable metal stents (C-SEMSs) by using a newly designed phantom model. In the phantom model, the stent was placed in differently sized holes in a silicone wall and retracted with a retraction robot. Resistance force to migration (RFM) was measured by a force gauge on the stent end. Radial force (RF) was measured with a RF measurement machine. Measured flare structure variables were the outer diameter, height, and taper angle of the flare (ODF, HF, and TAF, respectively). Correlations between RFM and RF or flare variables were analyzed using a linear correlated model. Out of the six stents, five stents were braided, the other was laser-cut. The RF and RFM of each stent were expressed as the average of five replicate measurements. For all six stents, RFM and RF decreased as the hole diameter increased. For all six stents, RFM and RF correlated strongly when the stent had not fully expanded. This correlation was not observed in the five braided stents excluding the laser cut stent. For all six stents, there was a strong correlation between RFM and TAF when the stent fully expanded. For the five braided stents, RFM after full stent expansion correlated strongly with all three stent flare structure variables (ODF, HF, and TAF). The laser-cut C-SEMS had higher RFMs than the braided C-SEMSs regardless of expansion state. RF was an important anti-migration property when the C-SEMS did not fully expand. Once fully expanded, stent flare structure variables plays an important role in anti-migration.

  7. Treatment of cuff-related tracheal stenosis with a fully covered retrievable expandable metallic stent

    International Nuclear Information System (INIS)

    Chen, G.; Wang, Z.; Liang, X.; Wang, Y.; Wang, Y.; Wang, Z.; Xian, J.

    2013-01-01

    Aim: To investigate the clinical effectiveness, complications, and optimal duration of use of covered retrievable expandable metallic stents in the management of cuff-related tracheal stenosis. Materials and methods: Twenty-one patients with cuff-related tracheal stenosis, Meyer–Cotton grade II (29%) and III (71%), who underwent fluoroscopically guided placement of covered retrievable expandable metallic stents were studied. Sixty-four-section computed tomography (CT) and bronchovideoscopy were performed prior to stent insertion, 1 month after stent insertion, in the case of stent-related complications, and after stent removal. Clinical manifestations, Hugh–Jones classification, and forced expiratory volume in 1 s (FEV1) were used to evaluate respiratory function before and after stent insertion and removal. The diameter of the stricture and FEV1 changes before insertion and after removal were analysed using the paired samples t-test. A p-value of ≤0.05 was considered statistically significant. Results: Twenty-one patients had 27 covered retrievable expandable metallic stents placed. Stents were electively removed from 20 patients. The median duration of stent placement was 5 months (range 4–12 months). One stent was not removed due to mucopolysaccharidosis type II (MPS II or Hunter syndrome) with tracheomalacia. After stent removal, airway dimensions increased and airway occlusion was symptomatically relieved in all patients. CT and bronchovideoscopy showed patent lumens with increased dimensions. Stent-related complications occurred in 19 (91%) patients, including granulation tissue formation (n = 18, 86%), stent migration and stent expectoration (n = 2, 10%), mucus plugging (n = 1, 5%), and halitosis (n = 6, 29%). Some patients experienced multiple complications, which were all managed effectively while the stent was still in place. There was a statistically significant difference in the diameter of the stricture and FEV1 between the time of stent

  8. Treatment of cuff-related tracheal stenosis with a fully covered retrievable expandable metallic stent.

    Science.gov (United States)

    Chen, G; Wang, Z; Liang, X; Wang, Y; Wang, Y; Wang, Z; Xian, J

    2013-04-01

    To investigate the clinical effectiveness, complications, and optimal duration of use of covered retrievable expandable metallic stents in the management of cuff-related tracheal stenosis. Twenty-one patients with cuff-related tracheal stenosis, Meyer-Cotton grade II (29%) and III (71%), who underwent fluoroscopically guided placement of covered retrievable expandable metallic stents were studied. Sixty-four-section computed tomography (CT) and bronchovideoscopy were performed prior to stent insertion, 1 month after stent insertion, in the case of stent-related complications, and after stent removal. Clinical manifestations, Hugh-Jones classification, and forced expiratory volume in 1 s (FEV1) were used to evaluate respiratory function before and after stent insertion and removal. The diameter of the stricture and FEV1 changes before insertion and after removal were analysed using the paired samples t-test. A p-value of ≤0.05 was considered statistically significant. Twenty-one patients had 27 covered retrievable expandable metallic stents placed. Stents were electively removed from 20 patients. The median duration of stent placement was 5 months (range 4-12 months). One stent was not removed due to mucopolysaccharidosis type II (MPS II or Hunter syndrome) with tracheomalacia. After stent removal, airway dimensions increased and airway occlusion was symptomatically relieved in all patients. CT and bronchovideoscopy showed patent lumens with increased dimensions. Stent-related complications occurred in 19 (91%) patients, including granulation tissue formation (n = 18, 86%), stent migration and stent expectoration (n = 2, 10%), mucus plugging (n = 1, 5%), and halitosis (n = 6, 29%). Some patients experienced multiple complications, which were all managed effectively while the stent was still in place. There was a statistically significant difference in the diameter of the stricture and FEV1 between the time of stent insertion and removal. An improvement in

  9. Covered Biodegradable Stent: New Therapeutic Option for the Management of Esophageal Perforation or Anastomotic Leak

    International Nuclear Information System (INIS)

    Černá, Marie; Köcher, Martin; Válek, Vlastimil; Aujeský, René; Neoral, Čestmír; Andrašina, Tomáš; Pánek, Jiří; Mahathmakanthi, Shankari

    2011-01-01

    Purpose: This study was designed to evaluate our experience with the treatment of postoperative anastomotic leaks and benign esophageal perforations with covered biodegradable stents. Materials and Methods: From 2008 to 2010, we treated five men with either an anastomotic leak or benign esophageal perforation by implanting of covered biodegradable Ella-BD stents. The average age of the patients was 60 (range, 38–74) years. Postoperative anastomotic leaks were treated in four patients (1 after esophagectomy, 1 after resection of diverticulum, 2 after gastrectomy). In one patient, perforation occurred as a complication of the treatment of an esophageal rupture (which occurred during a balloon dilatation of benign stenosis) with a metallic stent. Results: Seven covered biodegradable stents were implanted in five patients. Primary technical success was 100%. Clinical success (leak sealing) was achieved in four of the five patients (80%). Stent migration occurred in three patients. In two of these patients, the leak had been sealed by the time of stent migration, therefore no reintervention was necessary. In one patient an additional stent had to be implanted. Conclusion: The use of biodegradable covered stents for the treatment of anastomotic leaks or esophageal perforations is technically feasible and safe. The initial results are promising; however, larger number of patients will be required to evaluate the capability of these biodegradable stents in the future. The use of biodegradable material for coverage of the stent is essential.

  10. Comparison of covered and uncovered self-expandable stents in the treatment of malignant biliary obstruction.

    Science.gov (United States)

    Flores Carmona, Diana Yamel; Alonso Lárraga, Juan Octavio; Hernández Guerrero, Angélica; Ramírez Solís, Mauro Eduardo

    2016-05-01

    Drainage with metallic stents is the treatment of choice in malignant obstructive jaundice. Technical and clinical success with metallic stents is obtained in over 90% and 80% of cases, respectively. There are self-expandable metallic stents designed to increase permeability. The aim of this study was to describe the results obtained with totally covered self-expandable and uncovered self-expandable metallic stents in the palliative treatment of malignant biliary obstruction. Sixty eight patients with malignant obstructive jaundice secondary to pancreatobiliary or metastatic disease not amenable to surgery were retrospectively included. Two groups were created: group A (covered self-expandable metallic stents) (n = 22) and group B (uncovered self-expandable metallic stents) (n = 46). Serum total bilirubin, direct bilirubin, alkaline phosphatase and gamma glutamyl transferase levels decreased in both groups and no statistically significant difference was detected (p = 0.800, p = 0.190, p = 0.743, p = 0.521). Migration was greater with covered stents but it was not statistically significant either (p = 0.101). Obstruction was greater in the group with uncovered stents but it was not statistically significant either (p = 0.476). There are no differences when using covered self-expandable stents or uncovered self-expandable stents in terms of technical and clinical success or complications in the palliative treatment of malignant obstructive jaundice.

  11. Covered Balloon-Expanding Stents in Airway Stenosis.

    Science.gov (United States)

    Majid, Adnan; Kheir, Fayez; Chung, Jey; Alape, Daniel; Husta, Bryan; Oh, Scott; Folch, Erik

    2017-04-01

    The balloon-expanding stents are widely available but rarely described for use within the tracheobronchial tree. This report describes our experience with these stents in airway stenosis particularly as a lobar salvage therapy. This was a retrospective review of all records in which the balloon-expanding stents were used at a tertiary medical center. Ages, sex, location of stenosis, etiology of stenosis, stent size, duration of stent placement and associated interventions for airway stenosis were recorded. Patient's self-reported respiratory symptoms, dyspnea scale, and radiographic imaging at baseline and after stent placement were also reported. Twenty-one Atrium iCAST stents were inserted in 18 patients with malignant and benign airway disease. The median age was 69.5 years (interquartile range, 53.5 to 74). Most stents (n=20, 95%) were deployed in the lobar airways. There was a significant improvement in the modified Medical Research Council dyspnea scale from median of 3 to 2 (Pstent placement was achieved in 15 patients (83%). No deaths were related to airway stenting complications. Adverse events related to stents included migration (n=2, 9.5%), granulation tissue formation (n=2, 9.5%) and mucus plugging (n=1, 4.8%). Lobar stenting with balloon-expanding metallic stents appears feasible, safe and improves symptoms as well as radiographic atelectasis in patients with lobar airway stenosis in this small case series. Larger studies are needed to confirm this observation and to address long-term safety.

  12. 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.

  13. Bile Duct Disruption Following Radiofrequency Ablation: Successful Repair Using a Covered Stent

    International Nuclear Information System (INIS)

    Thompson, Philip M.; Hare, Christopher M.B.; Lees, William R.

    2004-01-01

    Persistent biliary leaks, whether iatrogenic or secondary to malignancy, often present a difficult management problem. Recent reports have suggested a role for covered metallic stents in this context. We describe the successful use of a covered stent to seal a persistent biliary leak following radiofrequency ablation of colorectal liver metastases

  14. Fully Covered Self-Expandable Metal Stents for Treatment of Both Benign and Malignant Biliary Disorders

    Directory of Open Access Journals (Sweden)

    Ahmed Abdel Samie

    2012-01-01

    Full Text Available Transpapillary stents are increasingly being used for biliary strictures, whether benign or malignant. However, there are different stent types and available data is controversial. Recently, completely covered self-expandable metal stents (CSEMSs have been proposed as an alternative therapeutic option in different biliary indications, including strictures of the distal bile duct, anastomotic stenosis after orthotopic liver transplantation, bile duct leaks, periampullary perforation following endoscopic sphincterotomy (ES, and postsphincterotomy bleeding. Despite the higher costs of these devices, fully covered self-expanding metal stents seem to be a suitable therapeutic option to relief biliary obstruction due to bile duct stenosis, regardless of the underlying cause.

  15. Fully Covered Self-Expandable Metal Stents for Treatment of Both Benign and Malignant Biliary Disorders

    Science.gov (United States)

    Abdel Samie, Ahmed; Theilmann, Lorenz

    2012-01-01

    Transpapillary stents are increasingly being used for biliary strictures, whether benign or malignant. However, there are different stent types and available data is controversial. Recently, completely covered self-expandable metal stents (CSEMSs) have been proposed as an alternative therapeutic option in different biliary indications, including strictures of the distal bile duct, anastomotic stenosis after orthotopic liver transplantation, bile duct leaks, periampullary perforation following endoscopic sphincterotomy (ES), and postsphincterotomy bleeding. Despite the higher costs of these devices, fully covered self-expanding metal stents seem to be a suitable therapeutic option to relief biliary obstruction due to bile duct stenosis, regardless of the underlying cause. PMID:22761543

  16. 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

  17. Post-biliary sphincterotomy bleeding despite covered metallic stent deployment

    Directory of Open Access Journals (Sweden)

    Gianfranco Donatelli

    2016-05-01

    Full Text Available Objectives: Several endoscopic techniques have been proposed for the management of post-sphincterotomy bleeding. Lately, self-expandable metal stents deployment has gained popularity especially as a rescue therapy when other endoscopic techniques fail. Methods-results: We report the case report of a massive post-sphincterotomy bleeding in a patient with a self-expandable metal stent in the biliary tree. Despite the presence of a correctly positioned self-expandable metal stent, a new endoscopic session was required to control the bleeding. Conclusions: Self-expandable metal stent may be useful to manage post-endoscopic sphincterotomy bleeding. However, up to now there is no specifically designed self-expandable metal stent for such complication. Large new designed self-expandable metal stent may be a useful tool for biliary endoscopist.

  18. Outcomes of Temporary Partially Covered Stent Placement for Benign Tracheobronchial Stenosis

    International Nuclear Information System (INIS)

    Ma, Ji; Han, Xinwei; Wu, Gang; Jiao, Dechao; Ren, Kewei; Bi, Yonghua

    2016-01-01

    PurposeTo evaluate the intermediate outcomes of temporary partially covered tracheobronchial stenting in patients with benign tracheobronchial stenosis.Materials and MethodsWe conducted a retrospective study of patients with benign tracheobronchial stenosis who underwent stent placement. All stents were removed approximately 3 months after placement. Respiratory function was assessed using the visual analogue scale (VAS) and Karnofsky performance status scale (KPS) before and after stent placement. The lumen diameters of the stenotic lesions were measured using chest computed tomography (CT) and compared between before stent placement and after stent removal.ResultsA total of 51 stents were successfully placed in consecutive 51 patients with benign tracheobronchial stenosis. No serious complications occurred. The mean VAS and KPS scores significantly improved after stent removal (6.291 ± 0.495 and 25.352 ± 10.533, respectively) compared with those before stent placement (1.493 ± 0.504 and 60.140 ± 16.344, respectively; P   0.05).ConclusionTemporary partially covered stenting may be a safe and effective treatment for benign tracheobronchial stenosis.

  19. Outcomes of Temporary Partially Covered Stent Placement for Benign Tracheobronchial Stenosis.

    Science.gov (United States)

    Ma, Ji; Han, Xinwei; Wu, Gang; Jiao, Dechao; Ren, Kewei; Bi, Yonghua

    2016-08-01

    To evaluate the intermediate outcomes of temporary partially covered tracheobronchial stenting in patients with benign tracheobronchial stenosis. We conducted a retrospective study of patients with benign tracheobronchial stenosis who underwent stent placement. All stents were removed approximately 3 months after placement. Respiratory function was assessed using the visual analogue scale (VAS) and Karnofsky performance status scale (KPS) before and after stent placement. The lumen diameters of the stenotic lesions were measured using chest computed tomography (CT) and compared between before stent placement and after stent removal. A total of 51 stents were successfully placed in consecutive 51 patients with benign tracheobronchial stenosis. No serious complications occurred. The mean VAS and KPS scores significantly improved after stent removal (6.291 ± 0.495 and 25.352 ± 10.533, respectively) compared with those before stent placement (1.493 ± 0.504 and 60.140 ± 16.344, respectively; P  0.05). Temporary partially covered stenting may be a safe and effective treatment for benign tracheobronchial stenosis.

  20. Multidetector-Row Computed Tomography in the Evaluation of Transjugular Intrahepatic Portosystemic Shunt Performed with Expanded-Polytetrafluoroethylene-Covered Stent-Graft

    International Nuclear Information System (INIS)

    Fanelli, Fabrizio; Bezzi, Mario; Bruni, Antonio; Corona, Mario; Boatta, Emanuele; Lucatelli, Pierleone; Passariello, Roberto

    2011-01-01

    We assessed, in a prospective study, the efficacy of multidetector spiral computed tomography (MDCT) in the evaluation of transjugular intrahepatic portosystemic shunt (TIPS) patency in patients treated with the Viatorr (Gore, Flagstaff, AZ) expanded-polytetrafluoroethylene (e-PTFE)-covered stent-graft. Eighty patients who underwent TIPS procedure using the Viatorr self-expanding e-PTFE stent-graft were evaluated at follow-up of 1, 3, 6, and 12 months with clinical and laboratory tests as well as ultrasound–color Doppler (USCD) imaging. In case of varices, upper gastrointestinal endoscopy was also performed. In addition, the shunt was evaluated using MDCT at 6 and 12 months. In all cases of abnormal findings and discrepancy between MDCT and USCD, invasive control venography was performed. MDCT images were acquired before and after injection of intravenous contrast media on the axial plane and after three-dimensional reconstruction using different algorithms. MDCT was successfully performed in all patients. No artefacts correlated to the Viatorr stent-graft were observed. A missing correlation between UCSD and MDCT was noticed in 20 of 80 (25%) patients. Invasive control venography confirmed shunt patency in 16 (80%) cases and shunt malfunction in 4 (20%) cases. According to these data, MDCT sensitivity was 95.2%; specificity was 96.6%; and positive (PPV) and negative predictive values (NPV) were 90.9 and 98.2%, respectively. USCD sensitivity was 90%; specificity was 75%; and PPV and NPV were 54.5 and 95.7%, respectively. A high correlation (K value = 0.85) between MDCT and invasive control venography was observed. On the basis of these results, MDCT shows superior sensitivity and specificity compared with USCD in those patients in whom TIPS was performed with the Viatorr stent-graft. MDCT can be considered a valid tool in the follow-up of these patients.

  1. Covered versus uncovered self-expandable metal stents for malignant biliary strictures: A meta-analysis and systematic review.

    Science.gov (United States)

    Moole, Harsha; Bechtold, Matthew L; Cashman, Micheal; Volmar, Fritz H; Dhillon, Sonu; Forcione, David; Taneja, Deepak; Puli, Srinivas R

    2016-09-01

    Self-expandable metal stents (SEMS) are used for palliating inoperable malignant biliary strictures. It is unclear if covered metal stents are superior to uncovered metal stents in these patients. We compared clinical outcomes in patients with covered and uncovered stents. Studies using covered and uncovered metallic stents for palliation in patients with malignant biliary stricture were reviewed. Articles were searched in MEDLINE, PubMed, and Ovid journals. Fixed and random effects models were used to calculate the pooled proportions. Initial search identified 1436 reference articles, of which 132 were selected and reviewed. Thirteen studies (n = 2239) for covered and uncovered metallic stents which met the inclusion criteria were included in this analysis. Odds ratio for stent occlusion rates in covered vs. uncovered stents was 0.79 (95 % CI = 0.65 to 0.96). Survival benefit in patients with covered vs. uncovered stents showed the odds ratio to be 1.29 (95 % CI = 0.95 to 1.74). Pooled odds ratio for migration of covered vs. uncovered stents was 9.9 (95 % CI = 4.5 to 22.3). Covered stents seemed to have significantly lesser occlusion rates, increased odds of migration, and increased odds of pancreatitis compared to uncovered stents. There was no statistically significant difference in the survival benefit, overall adverse event rate, and patency period of covered vs. uncovered metal stents in patients with malignant biliary strictures.

  2. Total loss of the covering of a metallic stent during esophageal leak treatment

    Directory of Open Access Journals (Sweden)

    J.J. Villarreal-Galvan

    2013-01-01

    Full Text Available A 41-year-old man underwent a Heller myotomy due to achalasia. An unexpected puncture in the esophageal wall was identified during the procedure. A partially covered 15 cm stent (PSEMS (UltraFlex was placed at the mucosal defect. It was removed 26 days later and the endoscopic image showed esophageal tissue embedded in the covered portion of the stent. PSEMS covering loss is a rare complication that can have serious consequences.

  3. Endovascular Treatment of Occlusive Lesions in the Aortic Bifurcation with Kissing Polytetrafluoroethylene-Covered Stents

    NARCIS (Netherlands)

    Grimme, F.A.B.; Spithoven, J.H.; Zeebregts, C.J.A.; Scharn, D.M.; Reijnen, M.M.

    2015-01-01

    PURPOSE: To determine the clinical outcomes of polytetrafluoroethylene covered balloon expandable stents (CBESs) in occlusive lesions of the aortic bifurcation in a kissing stent configuration. MATERIALS AND METHODS: The study included 69 consecutive patients (29 men, 40 women) who underwent kissing

  4. Endovascular Treatment of Occlusive Lesions in the Aortic Bifurcation with Kissing Polytetrafluoroethylene-Covered Stents

    NARCIS (Netherlands)

    Grimme, Frederike A. B.; Spithoven, J. Hans; Zeebregts, Clark J.; Scharn, Dirk M.; Reijnen, Michel M. P. J.

    Purpose: To determine the clinical outcomes of polytetrafluoroethylene covered balloon expandable stents (CBESs) in occlusive lesions of the aortic bifurcation in a kissing stent configuration. Materials and Methods: The study included 69 consecutive patients (29 men, 40 women) who underwent kissing

  5. Polyurethane-Covered Self-expandable Nitinol Stent for Malignant Biliary Obstruction: Preliminary Results

    International Nuclear Information System (INIS)

    Han, Young-Min; Hwang, Seung-Bae; Lee, Soo-Teik; Lee, Jeong-Min; Chung, Gyung-Ho

    2002-01-01

    Purpose: To evaluate the immediate and long-term results in ten patients with malignant biliary obstruction using a polyurethane-covered, self-expandable nitinol stent.Methods: A nitinol stent, fully covered with high-elasticity polyurethane, with an unconstrained diameter of 10 mm and a total length of 60-80 mm, was placed transhepatically under fluoroscopic guidance in ten patients. The length of the biliary obstruction varied between 30-50 mm. The follow-up examination included a clinical assessment, serum bilirubin measurement, and ultrasound examinations at one-month intervals in all patients. Results: Initial stent deployment was successful in eight patients. Two patients experienced proximal migration,which was solved by insertion of two, uncovered Wallstents. One patient had the stent removed after two weeks because of severe nausea and vomiting. One patient had delayed migration of the covered stent after 40 weeks. The follow-up duration was 3-40 weeks (Mean: 16.9 weeks). Seven patients died(3-26 weeks) and three patients survived (24-40 weeks). The bilirubin measurements in all patients had significantly decreased one week after stent insertion. The levels of amylase and lipase had did not increase after stent insertion. Conclusions: Apolyurethane-covered, self-expandable nitinol stent can be used effectively and safely in the treatment of malignant biliary obstruction. The preliminary results are favorable, but there is a need for further large studies to determine both long-term survival and patency

  6. Emergency and elective implantation of covered stent systems in iatrogenic arterial injuries

    International Nuclear Information System (INIS)

    Goltz, J.P.; Kickuth, R.; Bastuerk, P.; Hoppe, H.; Triller, J.

    2011-01-01

    Purpose: To evaluate the effectiveness and safety of covered stents for the management of iatrogenic arterial injury. Materials and Methods: Between 03/1998 and 12/2009, 31 patients underwent selective covered stent implantation after iatrogenic arterial injury. 12/31 of these patients (38.7 %) were hemodynamically unstable. Six different endovascular covered stent types were utilized. The primary endpoints of this study were technical and clinical success and rates of minor and major complications. Results: Initial angiograms demonstrated active extravasation in 19 (61.3 %) patients and pseudoaneurysms in 12 (38.7 %) patients. The following sites of bleeding origin were detected: axillary artery, subclavian artery, common iliac artery, external iliac artery, internal iliac artery, common femoral artery, superficial femoral artery, popliteal and fibular artery, femoro-popliteal and popliteo-crural bypasses, common hepatic artery, aberrant hepatic artery, cystic and gastroduodenal artery. In all patients bleeding was effectively controlled by covered stent implantation resulting in an immediate technical success of 100 %. Clinical success attributed to covered stent implantation was documented in 30 of the 31 patients (96.8 %). Major complications included death in four patients (11.1 %), acute thrombosis with arm ischemia in one patient (2.8 %) and stent fracture with associated pseudoaneurysm in another patient (2.8 %). In 2/31 patients (6.5 %) covered stent failure was detected and successfully treated by implantation of a second covered stent. Conclusion: Emergency and elective implantation of covered stents may be used for minimally invasive and effective management of iatrogenic arterial injury. (orig.)

  7. Outcomes of Prosthetic Hemodialysis Grafts after Deployment of Bare Metal versus Covered Stents at the Venous Anastomosis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Charles Y., E-mail: charles.kim@duke.edu; Tandberg, Daniel J.; Rosenberg, Michael D.; Miller, Michael J.; Suhocki, Paul V.; Smith, Tony P. [Duke University Medical Center, Division of Vascular and Interventional Radiology (United States)

    2012-08-15

    Purpose: To compare postintervention patency rates after deployment of bare metal versus covered stents across the venous anastomosis of prosthetic arteriovenous (AV) grafts. Methods: Review of our procedural database over a 6 year period revealed 377 procedures involving stent deployment in an AV access circuit. After applying strict inclusion criteria, our study group consisted of 61 stent deployments in 58 patients (median age 58 years, 25 men, 33 women) across the venous anastomosis of an upper extremity AV graft circuit that had never been previously stented. Both patent and thrombosed AV access circuits were retrospectively analyzed. Within the bare metal stent group, 20 of 32 AV grafts were thrombosed at initial presentation compared to 18 of 29 AV grafts in the covered stent group. Results: Thirty-two bare metal stents and 29 covered stents were deployed across the venous anastomosis. The 3, 6, and 12 months primary access patency rates for bare metal stents were not significantly different than for covered stents: 50, 41, and 22 % compared to 59, 52, and 29 %, respectively (p = 0.21). The secondary patency rates were also not significantly different: 78, 78, and 68 % for bare metal stents compared to 76, 69, and 61 % for covered stents, respectively (p = 0.85). However, covered stents demonstrated a higher primary stent patency rate than bare metal stents: 100, 85, and 70 % compared to 75, 67, and 49 % at 3, 6, and 12 months (p < 0.01). Conclusion: The primary and secondary access patency rates after deployment of bare metal versus covered stents at the venous anastomosis were not significantly different. However, bare metal stents developed in-stent stenoses significantly sooner.

  8. Outcomes of Prosthetic Hemodialysis Grafts after Deployment of Bare Metal versus Covered Stents at the Venous Anastomosis

    International Nuclear Information System (INIS)

    Kim, Charles Y.; Tandberg, Daniel J.; Rosenberg, Michael D.; Miller, Michael J.; Suhocki, Paul V.; Smith, Tony P.

    2012-01-01

    Purpose: To compare postintervention patency rates after deployment of bare metal versus covered stents across the venous anastomosis of prosthetic arteriovenous (AV) grafts. Methods: Review of our procedural database over a 6 year period revealed 377 procedures involving stent deployment in an AV access circuit. After applying strict inclusion criteria, our study group consisted of 61 stent deployments in 58 patients (median age 58 years, 25 men, 33 women) across the venous anastomosis of an upper extremity AV graft circuit that had never been previously stented. Both patent and thrombosed AV access circuits were retrospectively analyzed. Within the bare metal stent group, 20 of 32 AV grafts were thrombosed at initial presentation compared to 18 of 29 AV grafts in the covered stent group. Results: Thirty-two bare metal stents and 29 covered stents were deployed across the venous anastomosis. The 3, 6, and 12 months primary access patency rates for bare metal stents were not significantly different than for covered stents: 50, 41, and 22 % compared to 59, 52, and 29 %, respectively (p = 0.21). The secondary patency rates were also not significantly different: 78, 78, and 68 % for bare metal stents compared to 76, 69, and 61 % for covered stents, respectively (p = 0.85). However, covered stents demonstrated a higher primary stent patency rate than bare metal stents: 100, 85, and 70 % compared to 75, 67, and 49 % at 3, 6, and 12 months (p < 0.01). Conclusion: The primary and secondary access patency rates after deployment of bare metal versus covered stents at the venous anastomosis were not significantly different. However, bare metal stents developed in-stent stenoses significantly sooner.

  9. Use of covered self-expandable stents for benign colorectal disorders in children.

    Science.gov (United States)

    Lange, Bettina; Sold, Moritz; Kähler, Georg; Wessel, Lucas M; Kubiak, Rainer

    2017-01-01

    There is a lack of experience with covered self-expandable stents for benign colorectal disorders in children. Five children (4M, 1F) with a median age of 5years (range, 6months-9years) who underwent treatment with covered self-expandable plastic (SEPSs) or self-expandable metal stents (SEMSs) for a benign colorectal condition between April 2005 and November 2013 were recruited to this retrospective study. Etiologies included: anastomotic stricture with (n=1) or without (n=3) simultaneous enterocutaneous fistula, as well as an anastomotic leak associated with enterocutaneous fistula (n=1). All children suffered from either Hirschsprung's disease (n=3) or total colonic aganglionosis (Zuelzer-Wilson syndrome) (n=2). Median duration of individual stent placement was 23days (range, 1-87days). In all cases up to five different stents were placed over time. At follow-up two patients were successfully treated without further intervention. In another patient the anastomotic stricture resolved fully, but a coexisting enterocutaneous fistula persisted. Overall, three patients did not improve completely following stenting and required definite surgery. Stent-related problems were noted in all cases. There was one perforation of the colon at stent insertion. Further complications consisted of stent dislocation (n=4), obstruction (n=1), formation of granulation tissue (n=1), ulceration (n=1) and discomfort (n=3). Covered self-expandable stents enrich the armamentarium of interventions for benign colorectal disorders in children including anastomotic strictures and intestinal leaks. A stent can be applied either as an emergency procedure (bridge to surgery) or as an adjuvant treatment further to endoscopy and dilatation. Postinterventional problems are frequent but there is a potential for temporary or definite improvement following stent insertion. Copyright © 2017. Published by Elsevier Inc.

  10. Covered Stent and Coils Embolization of a Pulmonary Artery Pseudoaneurysm After Gunshot Wound

    Energy Technology Data Exchange (ETDEWEB)

    Huet, Nicolas, E-mail: nhuet@chu-grenoble.fr; Rodiere, Mathieu, E-mail: mrodiere@chu-grenoble.fr [Hôpital Universitaire de Grenoble and Université Grenoble Alpes, Department of Radiology and Medical Imaging (France); Badet, Michel, E-mail: michel.badet@ch-chambery.fr [Centre Hospitalier Métropôle Savoie, site de Chambéry, Intensive Care Unit (France); Michoud, Marie, E-mail: marie.michoud@ch-chambery.fr [Centre Hospitalier Métropôle Savoie, Site de Chambéry, Department of Radiology (France); Brichon, Pierre-Yves, E-mail: pybrichon@chu-grenoble.fr [Hôpital Universitaire de Grenoble and Université Grenoble Alpes, Department of Thoracic and Vascular Surgery (France); Ferretti, Gilbert, E-mail: gferretti@chu-grenoble.fr; Thony, Frédéric, E-mail: fthony@chu-grenoble.fr [Hôpital Universitaire de Grenoble and Université Grenoble Alpes, Department of Radiology and Medical Imaging (France)

    2016-05-15

    We report the first case of endovascular covered stent implantation for the treatment of a large pulmonary artery pseudoaneurysm (PAPA) following a right thoracic gunshot wound. After resuscitation and hemodynamic stabilization, a CT angiography was performed to analyze the neck size of the PAPA and its position relative to the branches of the parent artery. Covered stent implantation with additional coil embolization was successfully performed. At the 4-year follow-up, the stents remained patent and there was neither pseudoaneurysm recurrence nor treatment-related complication.

  11. Covered Stent and Coils Embolization of a Pulmonary Artery Pseudoaneurysm After Gunshot Wound

    International Nuclear Information System (INIS)

    Huet, Nicolas; Rodiere, Mathieu; Badet, Michel; Michoud, Marie; Brichon, Pierre-Yves; Ferretti, Gilbert; Thony, Frédéric

    2016-01-01

    We report the first case of endovascular covered stent implantation for the treatment of a large pulmonary artery pseudoaneurysm (PAPA) following a right thoracic gunshot wound. After resuscitation and hemodynamic stabilization, a CT angiography was performed to analyze the neck size of the PAPA and its position relative to the branches of the parent artery. Covered stent implantation with additional coil embolization was successfully performed. At the 4-year follow-up, the stents remained patent and there was neither pseudoaneurysm recurrence nor treatment-related complication.

  12. Customized Hinged Covered Metallic Stents for the Treatment of Benign Main Bronchial Stenosis.

    Science.gov (United States)

    Han, Xinwei; Al-Tariq, Quazi; Zhao, Yanle; Li, Lei; Cheng, Zhe; Wang, Huaqi; Liu, Chao; Jiao, Dechao; Wu, Gang

    2017-08-01

    To address the limitations of silicone stents, we designed a hinged self-expandable covered metallic stent. The aim of this study was to evaluate the safety and efficacy of the customized stents in clinical applications. This was a retrospective analysis. Under conscious sedation and local anesthesia, the stents were implanted or removed by interventional radiologists, with fluoroscopic guidance. Of 24 patients with benign main bronchial stenosis, stents were successfully placed in 21 (87.5%). The low-pressure balloon before dilation failed in 1 case (4.17%) of left main bronchial cicatricial stenosis. In 2 other cases (8.33%), stent placement was abandoned. Stents were successfully removed between 29 and 103 days after the procedure. After stent removal, the follow-up lasted for at least 12 months. Restenosis occurred only in 1 case (4.55%) owing to bronchial collapse 3 days after stent removal. Dyspnea occurred in another case (4.55%) at 2 months after retrieval; recurrence was confirmed using bronchoscopy, leading to a left pneumonectomy. The described procedure is safe and easy to be performed and avoids the use of intubation, bronchoscopy, and general anesthesia. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  13. Comparison of Covered Versus Uncovered Stents for Benign Superior Vena Cava (SVC) Obstruction.

    Science.gov (United States)

    Haddad, Mustafa M; Simmons, Benjamin; McPhail, Ian R; Kalra, Manju; Neisen, Melissa J; Johnson, Matthew P; Stockland, Andrew H; Andrews, James C; Misra, Sanjay; Bjarnason, Haraldur

    2018-05-01

    To identify whether long-term symptom relief and stent patency vary with the use of covered versus uncovered stents for the treatment of benign SVC obstruction. We retrospectively identified all patients with benign SVC syndrome treated to stent placement between January 2003 and December 2015 (n = 59). Only cases with both clinical and imaging follow-up were included (n = 47). In 33 (70%) of the patients, the obstruction was due to a central line or pacemaker wires, and in 14 (30%), the cause was fibrosing mediastinitis. Covered stents were placed in 17 (36%) of the patients, and 30 (64%) patients had an uncovered stent. Clinical and treatment outcomes, complications, and the percent stenosis of each stent were evaluated. Technical success was achieved in all cases at first attempt. Average clinical and imaging follow-up in years was 2.7 (range 0.1-11.1) (covered) and 1.7 (range 0.2-10.5) (uncovered), respectively. There was a significant difference (p = 0.044) in the number of patients who reported a return of symptoms between the covered (5/17 or 29.4%) and uncovered (18/30 or 60%) groups. There was also a significant difference (p = stenosis after stent placement between the covered [17.9% (range 0-100) ± 26.2] and uncovered [48.3% (range 6.8-100) ± 33.5] groups. No significant difference (p = 0.227) was found in the time (days) between the date of the procedure and the date of clinical follow-up where a return of symptoms was reported [covered: 426.6 (range 28-1554) ± 633.9 and uncovered 778.1 (range 23-3851) ± 1066.8]. One patient in the uncovered group had non-endovascular surgical intervention (innominate to right atrial bypass), while none in the covered group required surgical intervention. One major complication (SIR grade C) occurred that consisted of a pericardial hemorrhagic effusion after angioplasty that required covered stent placement. There were no procedure-related deaths. Both covered and uncovered stents can be used for

  14. Successful stent-in-stent insertion of an expandable metallic stent covered with polyuretane placed to obliterate a large bronchial fistula after chemoradiotherapy for inoperable lung cancer

    International Nuclear Information System (INIS)

    Minami, Hiroya; Tsubota, Noriaki; Miyamoto, Yoshifumi; Yoshimura, Masahiro; Obayashi, Kayoko; Takada, Yoshiki

    1999-01-01

    Bronchial fistulas in cases of inoperable lung cancer caused by radiochemotherapy are quite refractory and generally cannot be surgically closed. A 45-year-old man with squamous cell carcinoma in the right lung underwent two courses of induction chemotherapy (135 mg CDDP, 5 mg VDS, 13.5 mg MMC) and radiation therapy (2 Gy x 22 times) for invasion of the right main bronchus, the pulmonary artery and superior vena cava. Just before the end of the second course, the empyem second to the bronchial fistula caused by tumor necrosis developed in the right upper bronchus, and fenestration was performed. After the operation, his condition improved remarkably, however the fistula enlarged into the right main bronchus and the purulent discharge flowed into the left lung. An expandable metallic stent (EMS) covered with polyuretane was inserted in the trachea and the left main bronchus to break aspiration pneumonia. As the covered EMS was too unstable to be fixed, a bare EMS was inserted in a stent-in-stent fashion. After the procedure he was followed at the O.P.D. and lived a relatively comfortable life for 9 months until his death due to tumor. We inserted the covered EMS in a stent-in-stent fashion to successfully obliterate a large bronchial fistula. (author)

  15. Clinical Application of Fully Covered Self-Expandable Metal Stents in the Treatment of Bronchial Fistula.

    Science.gov (United States)

    Cao, Ming; Zhu, Qiang; Wang, Wei; Zhang, Tian Xiao; Jiang, Min Zhong; Zang, Qi

    2016-09-01

    Background The study was designed to access the feasibility, safety, and efficacy of fully covered self-expandable metal stents in the treatment of bronchial fistula. Methods Clinical data of nine patients (seven males and two females) who were treated with placement of tracheobronchial or bronchial fully covered self-expandable metal stents from August 2005 to November 2011 were analyzed retrospectively. Among these patients, seven were diagnosed with bronchopleural fistula, one with tracheopleural fistula, and one with left main bronchoesophageal fistula. Eight had accompanying thoracic empyema. The fistula orifices ranged from 3.5 mm to 25 mm in diameter. All patients received topical anesthesia. L-shaped stents were placed in six patients and I-shaped stents in three under fluoroscopic guidance. After stent placement, patients with empyema were treated with pleural lavage. Results Stent placement in the tracheobronchial tree was successful in all patients, without procedure-related complications. The operating time was 5 to 16 minutes. A small amount of bubble overflowed from the intrathoracic drainage tube of only one patient. In the other patients, the bubble in the intrathoracic drainage tube disappeared immediately or angiography showed no overflow of contrast agent from the fistula orifice. The effective rate of fistula orifice closure after stent placement was 100%, with 88.9% rated as excellent. One patient coughed the stent out 5 days after placement and hence a new stent was placed. Among the patients with empyema, one died of septicemia arising from empyema on day 8 and another died of brain metastases of lung cancer 6 months after stent insertion with persistent empyema. In the other six patients, empyema resolved after 2 to 5 months (cure rate 75%). Seven patients were followed up for 3 to 36 months. During follow-up, one stent was removed 8 months after implantation due to difficult expectoration, without recurrent empyema. The remaining

  16. [Clinical application of a fully covered self-expandable metallic stent in treatment of airway fistula].

    Science.gov (United States)

    Zhu, Qiang; Zang, Qi; Jiang, Zhong-min; Wang, Wei; Cao, Ming

    2013-06-01

    To assess the feasibility, safety and efficacy of the use of a fully covered self-expandable stent for the treatment of airway fistula. From August 2005 to November 2011, 9 patients underwent treatment by the introduction of a tracheo-bronchial or bronchial fully covered self-expandable metallic stent. There were 7 males and 2 females, aged from 28-65 years with a mean of 46 years. In this group, 7 cases were diagnosed as bronchopleural fistula, 1 case as tracheopleural fistula, 1 case as broncho-esophageal fistula, 8 cases with thoracic empyema. The fistula orifices were from 3.5-25.0 mm in diameter with a mean 8.4 mm. All patients received topical anesthesia, and L-shaped stent was placed in 6 patients and I-shaped stent in 3 patients under fluoroscopic guidance. After the stent placement, the patients with empyema were treated with continual irrigation of the empyema cavity. Stent placement in the tracheo-bronchial tree was technically successful in all patients, without procedure-related complications. The operating time was from 5-16 minutes, mean time (10 ± 4) minutes. Except for 1 patient, immediate closure of the airway fistula was achieved in the other patients after the procedure, as shown by the immediate cessation of bubbling in the chest drain system or the contrast examination. In this study, 1 patient coughed the inserted stent out due to irritable cough on the 5th day and had to receive repositioning of a new stent. Among the patients who were with empyema, 1 patient died of septicemia on the 8th day and 1 patient died of brain metastases from lung cancer 6 months after the stent insertion with empyema not cured, the other 6 patients' empyema healed from 2-5 months, mean time 3.7 months. Seven patients were followed from 3 to 36 months with a median of 13.5 months. During follow-up, 1 stent was removed from a patient 8 months after the stent implantation without empyema recurred. The remaining patient presented good tolerability to the existence of

  17. Long-term patency of experimental magnetic compression gastroenteric anastomoses achieved with covered stents.

    Science.gov (United States)

    Cope, C; Ginsberg, G G

    2001-06-01

    Our aim was to evaluate the efficacy of a prototype "YO-YO"-shaped covered stent for keeping experimental magnetic compression gastroenteric fistulas patent for 6 months. Magnets were introduced perorally with endoscopic and fluoroscopic guidance and were mated across the gastric and jejunal walls of 5 dogs. After a mean of 5.5 days a 12-mm diameter YO-YO stent was placed perorally in the resulting fistula. The gastroenteric anastomosis (GEA) with stent was observed endoscopically and gastrographically at 1- to 2-month intervals. There was no morbidity and there were no significant weight changes. The GEA was widely patent at necropsy at 6 months (n = 4); partial membrane separation occurred at 5 months in the fifth dog. There was minor breakage of the stent prongs in 2 animals. Peroral creation of a stented magnetic compression GEA is safe and provides long-term patency. This technique may be potentially useful for managing gastric outlet obstruction caused by malignancy.

  18. cancerous esophagotracheal fistula: treatment of placement with covered self-expanding metallic stent

    International Nuclear Information System (INIS)

    Han Xinwei; Li Tianxiao; Wang Ruilin; Fan Qingxia

    1997-01-01

    Purpose: To treat the esophagotracheal fistula that was the main cause of death in patients with esophageal carcinoma, the placement of the stent was studied. Materials and methods: Under the fluoroscopic guidance, 28 stents (5 stents made in USA and 23 in China) were successfully implanted in all the 28 patients with esophagotracheal fistula. Results: The aphagia of the patients was greatly improved and a normal diet could be swallowed at once after the placement of the stents. The 27 cases of inhalation pneumonia that caused by the fistula was recovered. Conclusion: The result indicated that the treatment with the placement of the covered self-expanding stent is simple, safe, and effective for most patients with aphagia and pneumonia due to esophagotracheal fistula

  19. COVERED STENTS IN IATROGENIC CORONARY ARTERY FISTULA; A CASE REPORT

    Directory of Open Access Journals (Sweden)

    Masoud Poormoghaddas

    2010-11-01

    Full Text Available Abstract    BACKGROUND: Coronary artery fistula is an abnormal communication between a coronary artery and a cardiac chamber or major cardiac vessels, mostly congenital but some of them are acquired as a consequence of coronary artery perforation.    CASE PRESENTATION: We report a case of cavity spilling coronary artery perforation during percutaneous coronary intervention 7 years ago. Because of continuing symptoms and risk of developing heart failure and pulmonary hypertension we were ought to treat this iatrogenically formed coronary artery fistula. We used stent graft implantation to treat it with acceptable results.    CONCLUSION: Beside their application as a rescue for acute coronary artery perforations, stent grafts can be used with acceptable results in iatrogenically acquired coronary artery coronary artery fistula      Keywords: Coronary artery perforation, Coronary artery fistula, Stent graft.

  20. Long Term Follow-up of a Transjugular Intrahepatic Portosystemic Shunt: A Comparison of Covered and Uncovered Stents

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Seung Moon; Park, Jae Hyung; Kim, Hyo Cheol; Jae, Hwan Jun; Chung, Jin Wook [Seoul National University Hospital, Seoul (Korea, Republic of)

    2009-01-15

    To evaluate the long term patency of transjugular intrahepatic portosystemic shunts (TIPS) and to compare the patency rate of covered and uncovered stents in TIPS. The study population included 78 patients with portal hypertension that underwent TIPS between January 1999 and July 2007 at our institution using uncovered stents in 53 patients and covered stents in 25 patients. The primary and secondary patency rates of TIPS were estimated to compare the uncovered and covered stent groups. The primary and secondary patency rates of the TIPS patients were found to be 83.9% and 93.9% at the 6 month follow-up and 73.5% and 88.5% at the12 month follow-up for uncovered and covered stents, respectively. A breakdown patency rates for the 12 month follow-up revealed that the primary patency rates were 76.6% and 66.3% for uncovered and covered stents, respectively; whereas, the secondary patency rates were 94.3% and 73.8% for the uncovered and covered stents, respectively. A comparative analysis did not provide evidence to suggest that a difference exists between the patency rates of the uncovered and covered stent groups (p>0.05). No significant difference was found between the patency rates of the uncovered and covered stent groups. A follow-up to this study would be a more thorough randomized evaluation of the different types of covered stents to compare long-term patency rates.

  1. Early and long-term clinical and radiological follow-up results of expanded-polytetrafluoroethylene-covered stent-grafts for transjugular intrahepatic portosystemic shunt procedures

    International Nuclear Information System (INIS)

    Maleux, Geert; Heye, Sam; Thijs, Maria; Wilms, Guy; Nevens, Frederik; Verslype, Chris; Wilmer, Alexander

    2004-01-01

    of TIPS can be obtained long-term after implantation of an e-PTFE-covered stent-graft, leading to a definitive resolution of portal hypertension-related complications. The incidence of TIPS-induced hepatic encephalopathy is acceptable. (orig.)

  2. Early and long-term clinical and radiological follow-up results of expanded-polytetrafluoroethylene-covered stent-grafts for transjugular intrahepatic portosystemic shunt procedures

    Energy Technology Data Exchange (ETDEWEB)

    Maleux, Geert; Heye, Sam; Thijs, Maria; Wilms, Guy [University Hospitals Gasthuisberg, Department of Radiology, Leuven (Belgium); Nevens, Frederik; Verslype, Chris [University Hospitals Gasthuisberg, Department of Hepatology, Leuven (Belgium); Wilmer, Alexander [University Hospitals Gasthuisberg, Department of Medical Intensive Care Unit, Leuven (Belgium)

    2004-10-01

    of TIPS can be obtained long-term after implantation of an e-PTFE-covered stent-graft, leading to a definitive resolution of portal hypertension-related complications. The incidence of TIPS-induced hepatic encephalopathy is acceptable. (orig.)

  3. Clinical remission following endoscopic placement of retrievable, fully covered metal stents in patients with esophageal achalasia.

    Science.gov (United States)

    Zeng, Y; Dai, Y-M; Wan, X-J

    2014-01-01

    Metal stents may represent an alternative therapy in the treatment of achalasia. We therefore evaluated the effectiveness of retrievable, fully covered metal stents in patients with achalasia. Fifty-nine patients with achalasia were treated with retrievable, fully covered metal stents. Symptoms using a global symptom score (0-10), lower esophageal sphincter (LES) resting pressure, LES relaxation, and simultaneous contraction of the esophagus were analyzed before and 1 week and 1 month after intervention. Complications and treatment outcomes were followed up at 6, 12, 18, and 24 months postoperatively. Stent placement was successful, and clinical symptoms resolved (P treatment in patients with achalasia. © 2013 Wiley Periodicals, Inc. and the International Society for Diseases of the Esophagus.

  4. Bending behaviors of fully covered biodegradable polydioxanone biliary stent for human body by finite element method.

    Science.gov (United States)

    Liu, Yanhui; Zhu, Guoqing; Yang, Huazhe; Wang, Conger; Zhang, Peihua; Han, Guangting

    2018-01-01

    This paper presents a study of the bending flexibility of fully covered biodegradable polydioxanone biliary stents (FCBPBs) developed for human body. To investigate the relationship between the bending load and structure parameter (monofilament diameter and braid-pin number), biodegradable polydioxanone biliary stents derived from braiding method were covered with membrane prepared via electrospinning method, and nine FCBPBSs were then obtained for bending test to evaluate the bending flexibility. In addition, by the finite element method, nine numerical models based on actual biliary stent were established and the bending load was calculated through the finite element method. Results demonstrate that the simulation and experimental results are in good agreement with each other, indicating that the simulation results can be provided a useful reference to the investigation of biliary stents. Furthermore, the stress distribution on FCBPBSs was studied, and the plastic dissipation analysis and plastic strain of FCBPBSs were obtained via the bending simulation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. 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

  6. Elective implantation of covered stents for coarctation and recoarctation in adolescents and adults.

    Science.gov (United States)

    Alcibar, Juan; Blanco, Roberto; Fernandez, Luis; Arriola, Josune; Garcia, Koldobika; Peña, Natividad; Inguanzo, Ramón; Voces, Roberto; Castellanos, Enrique; Montes, Pedro M

    2013-06-01

    Stent implantation is an effective therapy for aortic coarctation and recoarctation. However, in adolescents and adults, aortic wall rupture and dissection can occur, as well as aneurysms during follow-up. In order to reduce these complications, we electively implant covered stents. Since 2005, we have performed the procedure using femoral access in 17 patients (2 adolescents and 15 adults), 16 electively and 1 as a rescue procedure. We used the Mullins technique in all cases, implanting a NuMED(®) covered stent. Good stent apposition was achieved in all 17 procedures; 8 patients required a distal flare. Gradient was reduced from 40 (16) mmHg to 2 (2) mmHg (P<.001) and lumen diameter increased from 4 (2) mm to 19 (3) mm (P<.001). Two exceptional cases are discussed: one patient with aortic wall rupture who underwent a rescue procedure using a stent within a covered stent and another patient with total obstruction and intercostal aneurysm in whom the outcome was fatal at 48 h postprocedure (autopsy is shown). Four-year clinical follow-up included Doppler echocardiography; an additional imaging technique was required in 13 patients. All patients recovered well and there were no complications. Covered stents are effective in treating coarctation and recoarctation in adolescents and adults, are the treatment of choice in patients with complex anatomy, and must be available in the operating room as a rescue device when implanting a conventional stent. Copyright © 2012 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

  7. Outcomes of Temporary Partially Covered Stent Placement for Benign Tracheobronchial Stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Ji; Han, Xinwei, E-mail: hanxinwei2006@163.com; Wu, Gang; Jiao, Dechao; Ren, Kewei; Bi, Yonghua [The First Affiliated Hospital of Zhengzhou University, Department of Interventional Radiology (China)

    2016-08-15

    PurposeTo evaluate the intermediate outcomes of temporary partially covered tracheobronchial stenting in patients with benign tracheobronchial stenosis.Materials and MethodsWe conducted a retrospective study of patients with benign tracheobronchial stenosis who underwent stent placement. All stents were removed approximately 3 months after placement. Respiratory function was assessed using the visual analogue scale (VAS) and Karnofsky performance status scale (KPS) before and after stent placement. The lumen diameters of the stenotic lesions were measured using chest computed tomography (CT) and compared between before stent placement and after stent removal.ResultsA total of 51 stents were successfully placed in consecutive 51 patients with benign tracheobronchial stenosis. No serious complications occurred. The mean VAS and KPS scores significantly improved after stent removal (6.291 ± 0.495 and 25.352 ± 10.533, respectively) compared with those before stent placement (1.493 ± 0.504 and 60.140 ± 16.344, respectively; P < 0.05). The mean lumen transverse diameters of the stenotic site in trachea and main bronchus after stent removal (17.235 ± 3.457 and 8.993 ± 0.961 mm; 1 month post-removal; 16.353 ± 4.132 and 8.357 ± 1.082 mm; 6 months post-removal) were significantly larger than those before stent placement (7.876 ± 2.351 and 2.143 ± 0.770 mm, respectively; P < 0.05). However, the mean lumen diameters between 1 and 6 months after stent removal had no significant difference (P > 0.05).ConclusionTemporary partially covered stenting may be a safe and effective treatment for benign tracheobronchial stenosis.

  8. Safety and Efficacy of a Fully Covered Self-Expandable Metallic Stent in Benign Airway Stenosis.

    Science.gov (United States)

    Fortin, Marc; Lacasse, Yves; Elharrar, Xavier; Tazi-Mezalek, Rachid; Laroumagne, Sophie; Guinde, Julien; Astoul, Philippe; Dutau, Hervé

    2017-01-01

    The use of self-expandable metallic stents (SEMS) in benign airway disease was the object of a boxed warning from the United States Food and Drug Administration in 2005 due to the risk of stent-related complications and difficulties associated with their removal. Third-generation fully covered SEMS have been commercialized since this warning and theoretically should not present the same difficulties associated with removal as they cannot become embedded in the airway mucosa. We aimed to examine the safety and efficacy of a specific third-generation SEMS, the Silmet stent. We reviewed the records of all patients treated for benign airway stenosis with third-generation Silmet SEMS from January 2011 to December 2015 at the North Hospital of Marseilles, France. Forty SEMS were inserted in 30 patients over this period. Twenty (50.0%) stents were removed because of stent-related complications after a median of 77.0 ± 96.6 days (migration 32.5%, granulation tissue formation 7.5%, subjective intolerance 5.0%, mucus plugging 2.5%, laryngeal edema 2.5%). There were no cases of stent-related mortality. All complications were managed successfully endoscopically. Thirty-six stents (90.0%) were removed successfully after a median of 122.0 ± 113.2 days without any complications. The clinical success rate of stent treatment was 40.7%. Third-generation SEMS are a safe treatment option for complex benign airway stenosis, but complications requiring stent removal are frequent. Further studies are needed to compare the performance of third-generation SEMS and silicone stents in benign airway stenosis. © 2017 S. Karger AG, Basel.

  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. Sealing of Airway Fistulas for Metallic Covered Z-type Stents

    Directory of Open Access Journals (Sweden)

    Hongwu WANG

    2011-08-01

    Full Text Available Background and objective Treating airway fistulas, including esophagorespiratory fistulas (ERFs, bronchopleural fistulas (BPFs, and tracheomediastinal fistulas (TMFs, is difficult. The aim of this study is to evaluate the safety and clinical efficacy of metallic covered Z-type stents (CZTS for the treatment of airway fistulas through bronchoscopy or fluroscopy. Methods Thirty-eight patients with fistulas between the esophagus, mediastina, and airways (32 ERFs, 5 BPFs, and 1 TMF were retrospectively reviewed after treatment with covered metallic esophageal and airway stents. The fistulas were caused by esophageal (n=26, bronchogenic (n=11, and thyroid (n=1 carcinomas. Results Forty-six fistulas were found in 38 patients. The fistula size ranged from 0.5 cm to 7.0 cm. Forty airway covered metal stents (24 Y-type, 8 L-type, and 8 I-type and 24 esophageal metal stents were placed. Complete responses to the sealing effects of fistulas were noted in 4.3% of all the fistulas, 60.9% showed complete clinical responses, 23.9% showed partial responses, and 10.9% showed no response. An effectivity rate of 89.1% was observed, and the median survival duration of all patients was 5 months. Conclusion The use of CZTS appears to be safe and feasible for the palliative treatment of ERFs, BPFs, and TMFs. Airway stent placement is recommended for patients with ERF. In the event that airway stents fail, esophageal stents should be given. Airway bifurcation stents were observed to be especially suitable for the sealing of fistulas near the trachea carina.

  11. Palliation of malignant gastric obstruction : fluoroscopic guided covered metallic stent placement

    International Nuclear Information System (INIS)

    Lee, Jeong Min; Han, Young Min; Kim, Chong Soo; Lee, Sang Yong; Choi, Ki Chul; Lee, Soo Tak; Han, Hyun Young

    2000-01-01

    To demonstrate the feasibility and clinical efficacy of self-expanding, covered metallic stent placement for the palliative treatment of malignant gastric obstruction. Under fluoroscopic guidance, the placement of self-expanding, covered stents was attempted in 23 patients (age range, 31-78 years) with inoperable or recurrent gastric malignancies. All 23 suffered dysphagia and/or vomiting after the ingestion of soft foods, or swallowing difficulty. Three different types of self-expanding, covered metallic stents were used and in all patients, these were placed perorally using over the guide wire technique. Success was defined both technically and clinically. Stent placement was technically successful in 19 patients (82.6%) but because the guidewire failed to successfully negotiate the sites at which there was obstruction, was unsuccessful in four (17.4%). Stent placement was well tolerated in all patients except one, in whom an acutely angled efferent loop from remnant stomach was present. In this case, stent placement required a strong metallic guidewire. After placement, 17 of the 19 patients (89.5%) were able to ingest solid and/or soft foods without dysphagia and showed a markedly decreased incidence of vomiting. Two others showed some improvement in the frequency of vomiting but were able to ingest only a liquid diet. In one patient, the stent migrated two days after the procedure. During the follow-up period of 2-7 months (mean, 74 days), there were no clinically significant complications. For the short-term palliative treatment of patients with gastric inlet or outlet obstruction, the placement of self-expanding metallic stents has proven relatively easy and safe, as well as reasonably effective. (author)

  12. 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.

  13. The design of trachea-main bronchial covered embranchment stent and the primary clinical application

    International Nuclear Information System (INIS)

    Han Xinwei; Wu Gang; Gao Xuemei; Li Yongdong; Wang Yanli; Ma Nan

    2004-01-01

    Objective: To design the trachea-main bronchus covered embranchment stent and study the primary treatment for thoracostomach main bronchial fistula and main bronchial stenosis. Methods: The stent was designed on the bases of the peculiar anatomic structure and the pathological changes of thoracostomach-main bronchial fistula and main bronchial stenosis. Under the fluoroscopic guidance, implantations were carried out in thoracostomach-carina fistula 1 case thoracostomach-left main bronchial fistula 1, thoracostomach-right main bronchial fistula and left main bronchial stenosis 1 case, altogether with 5 stents. Results: Stents were placed successfully, not only improving the breathing and living quality but also completing the closure of the ora of the thoracostomach-airway fistula with further vanishing of the choke after drinking and eating together with the inhalation pneumonia. The bronchus became normal in a main bronchial stenosis after the stent was taken out. Conclusions: Trachea-main bronchial covered embranchment stent could be used to close thoracostomach-airway fistula and to treat main bronchial benign/malignant stenosis. The procedure is simple and safe. (authors)

  14. Esophageal carcinoma treatment with self-expanding covered stent implanted in esophagus

    International Nuclear Information System (INIS)

    Liu Mingguo; Ji Yan; He Nengwei

    2006-01-01

    Objective: To investigate the clinical significance of the treatment to esophageal cancer by self- expanding covered stent implanted into esophagus. Methods: Under fluoroscopic guidance and with guidance wire , 20 self-expanding covered stents were implanted into stenotic part of esophagus to recanalize the esophagus, then follow up to observe the clinical symptom improved. Results: Technical success was obtained 20 cases without any complication. Clinical symptom were improved in shot time. Conclusions: self-expanding covered stent is implanted in stenotic part of esophageal carcinoma to treat esophageal stenosis and enable to improved clinical symptom in shot time, if combined with transcatheter arterial infusion and embolization, Radiotherapy, Chinese medical treatment, it enable to lengthen life time remarkably. (authors)

  15. Efeitos a curto prazo de "stents" não recobertos e recobertos com politetrafluoroetileno em aorta de suínos: um modelo experimental Short-term effects of polytetrafluoroethylene covered and uncovered metallic "stents" in pig aorta: an experimental model

    Directory of Open Access Journals (Sweden)

    Marco Aurélio Grüdtner

    2004-04-01

    Full Text Available OBJETIVO: Descrever um estudo experimental avaliando através da morfometria digital o espessamento intimal na parede arterial após o implante de "stents" metálicos auto-expansíveis recobertos ou não com politetrafluoroetileno (PTFE na aorta de suínos. MÉTODOS: Em três grupos de suínos jovens uma bainha introdutora de 12 F foi inserida na aorta abdominal distal. Os animais do grupo I (n=5 foram considerados controle. Os animais do grupo II (n=10 receberam o implante de um stent metálico auto-expansível não recoberto. No grupo III (n=10 um stent auto-expansível recoberto com PTFE foi inserido. Após quatro semanas os animais foram sacrificados e os espécimes arteriais foram retirados, sendo o espessamento intimal quantificado pela análise morfométrica. RESULTADOS: Na comparação entre os grupos I, II e III quanto às áreas da íntima, média e índice intimal, não foi observada variação estatisticamente significativa. Diferenças foram observadas entre os grupos em relação às áreas luminais proximais (p=0,0036 e distais (p=0,044. Através dos testes de comparação múltipla para Kruskal-Wallis foi identificada uma diferença entre os grupos I e II. Entretanto, quando essas variáveis foram controladas pelo fator peso (relação área luminal/peso, a diferença não foi mais observada. CONCLUSÕES: Nesse estudo a curto prazo, o revestimento de PTFE não esteve associado a adicional espessamento intimal além daquele promovido pelo dispositivo metálico em artérias de grande calibre e condições de alto fluxo.PURPOSE: To report an experimental study evaluating, through digital morphometry, the intimal thickening of the arterial wall after the implant of auto-expandable stainless steel stents covered or not with polytetrafluoroethylene (PTFE in the pig aorta. METHODS: In three groups of pigs a 12 F sheath was inserted in distal abdominal aorta. Group I animals (n=5 served as control. Group II animals (n=10 received an auto

  16. Polyorethaoe-covered nitinol strecker stents as primary palliative treatment of malignant biliary obstruction

    International Nuclear Information System (INIS)

    Kanasaki, Shuzo; Furukawa, Akira; Kane, Teruyuki; Murata, Kiyoshi

    2000-01-01

    Purpose: To evaluate the clinical efficacy of the polyure-thane-covered Nitinol Strecker stent in the treatment of patients with malignant biliary obstruction.Methods: Twenty-three covered stents produced by us were placed in 18 patients with malignant biliary obstruction. Jaundice was caused by cholangiocarcinoma (n=5), pancreatic Cancer (n=6), gallbladder Cancer (n=4), metastatic lymph nodes (n=2), and tumor of the papilla (n=1).Resulrs: The mean patency period of the Stents was 37.5 weeks (5-106 weeks). Recurrent obstructive jaundice occurred in two patients (11%). Adequate biliary drainage over 50 weeks or until death was achieved in 17 of 18 patients (94.4%). Late cholangitis was observed in two patients whose stents bridged the ampulla of Vater. Other late severe complications were not encountered.Conclusion: Although more study is necessary, our results suggest the clinical efficacy of our covered Nitinol Strecker stent in the management of obstructive jaundice caused by malignant diseases.

  17. Fully Covered Metallic Stents for the Treatment of Benign Airway Stenosis.

    Science.gov (United States)

    Dahlqvist, Caroline; Ocak, Sebahat; Gourdin, Maximilien; Dincq, Anne Sophie; Putz, Laurie; d'Odémont, Jean-Paul

    2016-01-01

    Introduction. We herein report our experience with new fully covered self-expanding metallic stents in the setting of inoperable recurrent benign tracheobronchial stenosis. Methods. Between May 2010 and July 2014, 21 Micro-Tech® FC-SEMS (Nanjing Co., Republic of Korea) were placed in our hospital in 16 patients for inoperable, recurrent (after dilatation), and symptomatic benign airway stenosis. Their medical files were retrospectively reviewed in December 2014, with focus on stent's tolerance and durability data. Results. Twenty-one stents were inserted: 13 for posttransplant left main bronchus anastomotic stricture, seven for postintubation tracheal stenosis, and one for postlobectomy anastomotic stricture. Positioning was easy for all of them. Stents were in place for a mean duration of 282 days. The most common complications were granulation tissue development (35%), migration (30%), and sputum retention (15%). Fifty-five % of the stents (11/20) had to be removed because of various complications, without difficulty for all of them. None of the patients had life-threatening complications. Conclusion. Micro-Tech FC-SEMS were easy to position and to remove. While the rate of complications requiring stent removal was significant, no life-threatening complication occurred. Further studies are needed to better define their efficacy and safety in the treatment of benign airway disease.

  18. Treating mediastinoesophageal fistula with covered stent through nasal esophagus drainage tube

    International Nuclear Information System (INIS)

    Han Xinwei; Wu Gang; Li Yongdong; Ma Nan; Wang Yanli; Gao Xuemei

    2005-01-01

    Objective: To investigate the value of treating mediastinoesophageal fistula with covered stent through nasal esophagus drainage tube. Methods: Ten patients with mediastinoesophageal fistula were treated by 5F catheter inserting into the abscess cavities through nasal esophageal fistula, with stent placement in the esophagus. The abscess cavities were washed and angiograghied through drainage tube and the sites of the drainage tube were adjusted in time until withdrawal of the tube. Results: The drainage tubes were pulled out within 10-25 days with disappearance of the abscess cavities and normal diet intake without difficulty. Conclusions: Treating mediastinoesophageal fistula with covered stent through nasal esophagus drainage tube is safe, microinvasive economic and acceptable, worth to be recommended. (authors)

  19. Comparison of the occlusion of experiemntal craniojugular saccular aneurysms with covered stents

    International Nuclear Information System (INIS)

    Zhang Haixia; Li Minghua; Cheng Yingsheng; Fang Chun; Li Min

    2006-01-01

    Objective: To assess the effectiveness and biocompatibility of balloon-expanding, stainless steel stents covered with biomembrane (BM-SSS) and polyurethane membrane (PUM-SSS) in the treatment of experimental saccular aneurysms in a canine model and to observe the ablation of aneurysm with preservation of the parent vessel. Methods: Sixteen healthy mongrel canines were included in our study. 26 of 29 successful experimental aneurysms were treated with covered stents, another 3 were untreated to serve as controls. Altogether there were fourteen BM-SSS and twelve PUM-SSS were placed endovascularly in the common carotid arteries covering the orifice of the aneurysms. Control angiography was performed immediately after the procedure and after 2 weeks, 4 weeks and 12 weeks. According to grouping time, each aneurysm together with stented arteries was removed with animals alive for histopathological examination. Enumeration data was analyzed by Fisher's Exact Test using SPSS 10.0. Results: Before stent placement, angiography of the common carotid arteries showed round, saccular side-wall aneurysms and complex pattern of flow. Immediately after stent placement the aneurysmal pouches were no longer visible and the stented common carotid arteries remained widely patent. All controlled aneurysms and common carotid arteries have been patent and unchanged for 1 year. 13 of 14 stented common carotid arteries with BM-SSS and 3 of 12 with PUM-SSS remained widely patent. The complete patency rate of BM-SSS and PUM-SSS was significantly different (P=0.0008). Histological analysis indicated that all treated aneurysmal pouches were almost filled with thrombus, as well as with fibrotic reactive scar tissue. Stent wires were found to be located deep within the vessel wall and encased by an extension of the tunica intima. The endothelium of the two groups was already mature at 12 weeks, and various degree of degenerate cells were seen under the transmission electron microscopy. Conclusion

  20. A fully-covered stent (Alimaxx-E) for the palliation of malignant dysphagia: a prospective follow-up study

    NARCIS (Netherlands)

    Uitdehaag, Madeleen J.; van Hooft, Jeanin E.; Verschuur, Els M. L.; Repici, Alessandro; Steyerberg, Ewout W.; Fockens, Paul; Kuipers, Ernst J.; Siersema, Peter D.

    2009-01-01

    Background: The majority of the Currently available metal stents are partially covered to reduce migration risk. However, one of the remaining issues is tissue ingrowth through the uncovered stent parts. Objective: To determine efficacy, recurrent dysphagia, and complications of a fully covered

  1. Treatment of a Left Internal Mammary Artery to Pulmonary Artery Fistula with Polytetrafluoroethylene Covered Stents: A Case Report and Review of the Literature

    International Nuclear Information System (INIS)

    Abbott, J. Dawn; Brennan, Joseph J.; Remetz, Michael S.

    2004-01-01

    Internal mammary artery (IMA) to pulmonary artery (PA) fistula is a rare complication of coronary artery bypass grafting (CABG) that may present as myocardial ischemia. We describe a case of left IMA-to-PA fistula treated with balloon expandable coronary polytetrafluoroethylene (PTFE) graft stents and review previously reported cases of this entity

  2. Evaluation of the biodurability of polyurethane-covered stent using a flow phantom

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Hyun; Kang, Sung Gwon; Choi, Jung Ryul; Byun, Ju Nam; Kim, Young Chul [Chosun University Hospital, Gwangju (Korea, Republic of); Ahn, Young Moo [Hansung Universkty, Seoul (Korea, Republic of)

    2001-06-01

    To evaluate the biodurability of the covering material in retrievable metallic stents covered with polycarbonate polyurethane. Using a peristaltic pump at a constant rate of 1ml/min, bile was recirculated from a reservoir through a long tube containing four stents. Each of these was removed from the system every two weeks and a radial tensile strength test and scanning electron microscopy (SEM) were performed. Each stent, removed at 2, 4, 6 and 8 weeks, was compared with a control stent not exposed to bile juice. Gross examination showed that stents were intact at 2 weeks, but at 4, 6 and 8 weeks cracks were observed. The size of these increased gradually in accordance with the duration of exposure, and at 8 weeks several large holes in the polyurethane membrane were evident. With regard to radial tensile strength, extension and peak load at break were 84.47% and 10.030 N/mm, 54.90% and 6.769 N/mm, 16.55% and 2.452 N/mm, 11.21% and 1.373 N/mm at 0, 2, 4 and 6 weeks, respectively. Scanning electron microscopy at 2 weeks revealed intermittent pitting and cracking, and examination at 4, 6 and 8 weeks showed that the size of these defects was gradually increasing. When the polyurethane membrane was exposed to bile, biodegradation was first observed at week two and increased gradually according to the duration of exposure.

  3. Fully covered self-expanding metal stents are effective for benign esophagogastric disruptions and strictures.

    Science.gov (United States)

    Wilson, Jennifer L; Louie, Brian E; Farivar, Alexander S; Vallières, Eric; Aye, Ralph W

    2013-12-01

    Self-expanding fully covered metal stents (CSs) are ideal for use in benign esophagogastric disease. We reviewed our experience with CS to evaluate outcomes, to determine a role for CS in a standard treatment for benign esophageal conditions, and to compare our results with recently published studies. We performed a retrospective chart review from 2005 to 2012. A total of 57 CSs were placed in 44 patients. Indications were stricture (11 patients), anastomotic leak (20), perforation (7), and tracheoesophageal fistulae (6). For GI tract disruptions, open repair or diversion was avoided in 31/33 patients (93.9 %) but required an associated drainage procedure in 22/33 (67 %) patients. Resolution does not depend on achieving radiological control with 6/26 (23 %) having evidence of a persistent leak. Benign strictures were dilated at a mean of 3.7 times prior to stenting. Adjunctive intra-mucosal steroid injections were used in 8/11 patients. Stents were removed at a mean of 33 days. At a mean of 283 days of follow-up, 6/11 (54.5 %) had symptom resolution. The most common complication was stent migration occurring in 17.5 % of patients overall. Covered stents are an effective adjunct in the management of benign upper gastrointestinal tract fistulae, leaks, perforations and benign strictures.

  4. Palliation of Postoperative Gastrointestinal Anastomotic Malignant Strictures with Flexible Covered Metallic Stents: Preliminary Results

    International Nuclear Information System (INIS)

    Lee, Jeong-Min; Han, Young Min; Lee, Sang Yong; Kim, Chong Soo; Yang, Doo Hyun; Lee, Seung Ok

    2001-01-01

    Purpose: To evaluate the efficacy of the placement of covered metallic stents for palliation of gastrointestinal anastomotic strictures secondary to recurrent gastric cancer.Methods: Under fluoroscopic guidance, placement of one or two self-expandable covered metallic stents was attempted perorally in 11 patents (aged 48-76 years) with anastomotic stenoses due to recurrent gastric malignancies. The strictures involved both the afferent and efferent loops in three patients. All patients had poor peroral food intake with severe nausea and vomiting after ingestion. The technical and clinical success was evaluated.Results: Placement of the covered stent was technically successful in 13 of 15 (87%) attempts in ten patients. After the procedure, 9 of 11 (82%) patients overall were able to ingest at least a liquid diet and had markedly decreased incidence of vomiting. During the follow-up of 2-31 weeks (mean 8.5 weeks) there were no major complications.Conclusion: These preliminary results suggest that flexible, covered stents may provide effective palliation of malignant anastomotic stricture secondary to recurrent gastric cancer

  5. 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.

  6. 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.)

  7. 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.)

  8. A newly designed Y-shaped covered stent in the palliative treatment of hepatic hilar malignant obstruction: Case report

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Byung Chul; Lee, So Won [Dept. of Radiology, Mokdong Hospital, Ewha Womans University College of Medicine, Seoul (Korea, Republic of); Chung, Hwan Hoon [Dept. of Radiology, Ansan Hospital, Korea University College of Medicine, Ansan (Korea, Republic of)

    2013-01-15

    We report a case in an inoperable patient with the hilar malignant biliary obstruction treated palliatively by the use of a newly designed Y-shaped covered stent without interfering contra-lateral bile duct. We percutaneously inserted a newly designed Y-shaped covered stent into a biliary tree in an inoperable patient with Bismuth Type II cholangiocarcinoma. We checked tubograms, enhanced CT studies, and blood bilirubin levels before, one week after, and at every three month after the stenting, by observing closely the signs of clinical infection as well. The follow-up period was about 12 months. The placement of the Y-shaped covered stent was successful and resulted in adequate biliary drainage in the immediate post-procedural tubogram and in the follow-up abdominal CT. The serum bilirubin levels did not show elevation after the insertion of the Y-shaped covered stent.

  9. The risk of endoleak following stent covering of the internal iliac artery during endovascular aneurysm repair

    International Nuclear Information System (INIS)

    Rajesparan, K.; Partridge, W.; Refson, J.; Abidia, A.; Aldin, Z.

    2014-01-01

    Aim: To investigate the risk of endoleak during endovascular aneurysm repair (EVAR) involving the distal common iliac artery (CIA) when the internal iliac artery (IIA) is covered without prior coil embolization. Materials and methods: Retrospective analysis of 145 (125 men, 20 women) consecutive EVAR cases. Clinical notes and radiological images were reviewed, and data collected on patient demographics, aneurysm morphology, covering of the IIA with or without embolization, presence of endoleaks, and patient symptoms relating to IIA ischaemia. Results: A total of 29 IIAs (10%) were covered in a total of 25 patients. Seven IIAs (24%) were embolized before stent covering (Embolization group), and 22 IIAs (76%) were covered only without embolization (Cover group). There was no statistically significant difference in the mean size of the abdominal aortic aneurysm diameter or CIA diameter between each group. No endoleaks from IIA retrograde filling were found in either group. Conclusion: The results of the present study do not support the traditional view that coverage of the IIA without prior embolization carries a high risk of endoleak, with no endoleaks seen in all 22 cases. Large-scale trials are required. However, the advent of branched-stenting techniques and the emergence of their success in long-term follow-up may preclude the former. - Highlights: • No EVAR endoleaks due to retrograde filling of the internal iliac artery (IIA). • No increased risk of endoleak with stent coverage of the IIA without embolisation. • Current evidence does not support traditional views

  10. 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 ...

  11. Fully Covered Metallic Stents for the Treatment of Benign Airway Stenosis

    Directory of Open Access Journals (Sweden)

    Caroline Dahlqvist

    2016-01-01

    Full Text Available Introduction. We herein report our experience with new fully covered self-expanding metallic stents in the setting of inoperable recurrent benign tracheobronchial stenosis. Methods. Between May 2010 and July 2014, 21 Micro-Tech® FC-SEMS (Nanjing Co., Republic of Korea were placed in our hospital in 16 patients for inoperable, recurrent (after dilatation, and symptomatic benign airway stenosis. Their medical files were retrospectively reviewed in December 2014, with focus on stent’s tolerance and durability data. Results. Twenty-one stents were inserted: 13 for posttransplant left main bronchus anastomotic stricture, seven for postintubation tracheal stenosis, and one for postlobectomy anastomotic stricture. Positioning was easy for all of them. Stents were in place for a mean duration of 282 days. The most common complications were granulation tissue development (35%, migration (30%, and sputum retention (15%. Fifty-five % of the stents (11/20 had to be removed because of various complications, without difficulty for all of them. None of the patients had life-threatening complications. Conclusion. Micro-Tech FC-SEMS were easy to position and to remove. While the rate of complications requiring stent removal was significant, no life-threatening complication occurred. Further studies are needed to better define their efficacy and safety in the treatment of benign airway disease.

  12. Covered self-expandable metallic stent placement for a post-operative malignant anastomotic stricture secondary to recurrent gastric cancer

    International Nuclear Information System (INIS)

    Lee, Woon Ha; Jung, Gyoo Sik; Kim, Kyu Jong; Lee, Sang Ho; Ko, Ji Ho; Jeong, Kyung Soon

    2007-01-01

    To evaluate the technical feasibility and clinical effectiveness of stent placement for the treatment of a post-operative malignant anastomotic stricture secondary to recurrent gastric cancer. Under fluoroscopic guidance, one or two covered stents were placed in 20 consecutive patients (age range, 44-75 years) with an anastomotic stricture due to a recurrent gastric malignancy. Before stent placement, all patients had severe nausea and recurrent vomiting after ingestion. Stent placement was technically successful for all patients, and no procedural complications occurred. After stent placement, 18 of 20 (90.0%) patients were able to ingest at least a liquid diet and had a markedly decreased incidence of vomiting. During the follow-up of 2-116 weeks (mean, 25.5 weeks), stent migration occurred in two patients (10.0%) on one day after the procedure. All patients with stent migration were treated successfully by means of placing a second stent. Three patients showed a recurrence of the stricture due to tumor overgrowth; two of the patients were treated with coaxial placement of a second stent. Another patient refused additional management. Covered self-expandable metallic stent placement seems to be technically feasible and effective for palliative treatment of a post-operative malignant anastomotic stricture secondary to recurrent gastric cancer

  13. Covered self-expandable metallic stent placement for a post-operative malignant anastomotic stricture secondary to recurrent gastric cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Woon Ha; Jung, Gyoo Sik; Kim, Kyu Jong; Lee, Sang Ho [Gospel Hospital, College of Medicine, Kosin University, Busan (Korea, Republic of); Ko, Ji Ho [Masan Samsung Medical Center, Sungkyunkwan University School of University, Masan (Korea, Republic of); Jeong, Kyung Soon [University of Ulsan Colleg of Medicine, Asan Medical Center, Seoul (Korea, Republic of)

    2007-09-15

    To evaluate the technical feasibility and clinical effectiveness of stent placement for the treatment of a post-operative malignant anastomotic stricture secondary to recurrent gastric cancer. Under fluoroscopic guidance, one or two covered stents were placed in 20 consecutive patients (age range, 44-75 years) with an anastomotic stricture due to a recurrent gastric malignancy. Before stent placement, all patients had severe nausea and recurrent vomiting after ingestion. Stent placement was technically successful for all patients, and no procedural complications occurred. After stent placement, 18 of 20 (90.0%) patients were able to ingest at least a liquid diet and had a markedly decreased incidence of vomiting. During the follow-up of 2-116 weeks (mean, 25.5 weeks), stent migration occurred in two patients (10.0%) on one day after the procedure. All patients with stent migration were treated successfully by means of placing a second stent. Three patients showed a recurrence of the stricture due to tumor overgrowth; two of the patients were treated with coaxial placement of a second stent. Another patient refused additional management. Covered self-expandable metallic stent placement seems to be technically feasible and effective for palliative treatment of a post-operative malignant anastomotic stricture secondary to recurrent gastric cancer.

  14. Preliminary clinical application in the cranial internal carotid artery of covered stents specially designed for intracranial vasculature

    International Nuclear Information System (INIS)

    Li Minghua; Luo Qiyi; Fang Chun; Xie Zhiyong; Cheng Yingsheng; Gao Bulang; Li Yu; Zhang Beilei; Xie Jian; Wang Yongli

    2007-01-01

    Objective: To investigate the flexibility of both the covered stents specially designed for use in intracranial vasculature and the delivering system in passing through the bone tube and the physiological curves of the cranial internal carotid artery (CICA) to reach the targeted area, the performance (adherence) of the covered stents in occluding vascular wall diseases and the impact on the vascular branches of the covered segment. Methods: The covered stents specially designed for use in intracranial vasculature were used to treat 13 patients with CICA diseases using endovascular techniques. There were 4 huge pseudoaneurysms, 4 giant aneurysms, 3 small wide-necked aneurysms, 1 giant pseudoaneurysm with concurrent internal carotid cavernous fistula (CCF), and 1 CCF. Prior to the detachment of the covered stents, balloon occlusion test (BOT) of the internal carotid artery on the diseased side and whole-brain digital subtraction angiography (DSA) were performed in all the patients. Three to 16 months following procedure, DSA and clinical follow-ups were performed. Results: Thirteen patients all tolerated the BOT well with the DSA demonstrating well-opened anterior and posterior communicating arteries. The covered stents and the delivering systems all successfully passed CICA to reach the targeted diseased area, with the diseased segments of the internal carotid artery including C3-C4 in 4 cases, C4-C5 in 4 and C6-C7 in 5. Immediately following the detachment of the covered stents, DSA demonstrated that 7 aneurysms were completely occluded, 4 aneurysms had slight endoleak, and 1 CCF had markedly-decreased blood flow through the fistula. In the patient with concurrent pseudoaneurysm and CCF, the pseudoaneurysm disappeared and the blood flow through the fistula was markedly-reduced immediately following the stenting procedure. Apart from one patient with aneurysmal subarachnoid hemorrhage who died due to extensive vascular spasm on the 9th day following the stenting

  15. Role of Fully Covered Self-Expandable Metal Stent for Treatment of Benign Biliary Strictures and Bile Leaks

    Energy Technology Data Exchange (ETDEWEB)

    Pausawasadi, Nonthalee [Department of Medicine, Siriraj Hospital, Mahidol University, Bangkok (Thailand); Soontornmanokul, Tanassanee; Rerknimitr, Rungsun [Department of Medicine, Chulalongkorn University, Bangkok (Thailand)

    2012-02-15

    Endoscopic therapy by balloon dilation and placement of multiple large-bore plastic stents is the treatment of choice for benign biliary stricture. This approach is effective but it typically requires multiple endoscopic sessions given the short duration of stent patency. The endoscopic approach for treatment of bile leak involves the placement of a stent with or without biliary sphincterotomy. The self-expandable metal stent (SEMS) has traditionally been used for palliation of malignant biliary strictures given the long duration of stent patency owing to their larger stent diameter. Recently, SEMS has been used in a variety of benign biliary strictures and leaks, especially with the design of the covered self-expandable metal stent (CSEMS), which permits endoscopic-mediated stent removal. The use of CSEMS in benign biliary stricture could potentially result in a decrease in endoscopic sessions and it is technically easier when compared to placement of multiple plastic stents. However, complications such as cholecystitis due to blockage of cystic duct, stent migration, infection and pancreatitis have been reported. The potential subsegmental occlusion of contralateral intrahepatic ducts also limits the use of CSEMS in hilar stricture. Certain techniques and improvement of stent design may overcome these challenges in the future. Thus, CSEMS may be appropriate in only highly selected conditions, such as refractory benign biliary stricture, despite multiple plastic stent placement or difficult to treat bile duct stricture from chronic pancreatitis, and should not be used routinely. This review focuses on the use of fully covered self-expandable metal stent for benign biliary strictures and bile leaks.

  16. Role of Fully Covered Self-Expandable Metal Stent for Treatment of Benign Biliary Strictures and Bile Leaks

    International Nuclear Information System (INIS)

    Pausawasadi, Nonthalee; Soontornmanokul, Tanassanee; Rerknimitr, Rungsun

    2012-01-01

    Endoscopic therapy by balloon dilation and placement of multiple large-bore plastic stents is the treatment of choice for benign biliary stricture. This approach is effective but it typically requires multiple endoscopic sessions given the short duration of stent patency. The endoscopic approach for treatment of bile leak involves the placement of a stent with or without biliary sphincterotomy. The self-expandable metal stent (SEMS) has traditionally been used for palliation of malignant biliary strictures given the long duration of stent patency owing to their larger stent diameter. Recently, SEMS has been used in a variety of benign biliary strictures and leaks, especially with the design of the covered self-expandable metal stent (CSEMS), which permits endoscopic-mediated stent removal. The use of CSEMS in benign biliary stricture could potentially result in a decrease in endoscopic sessions and it is technically easier when compared to placement of multiple plastic stents. However, complications such as cholecystitis due to blockage of cystic duct, stent migration, infection and pancreatitis have been reported. The potential subsegmental occlusion of contralateral intrahepatic ducts also limits the use of CSEMS in hilar stricture. Certain techniques and improvement of stent design may overcome these challenges in the future. Thus, CSEMS may be appropriate in only highly selected conditions, such as refractory benign biliary stricture, despite multiple plastic stent placement or difficult to treat bile duct stricture from chronic pancreatitis, and should not be used routinely. This review focuses on the use of fully covered self-expandable metal stent for benign biliary strictures and bile leaks.

  17. Role of Fully Covered Self-Expandable Metal Stent for Treatment of Benign Biliary Strictures and Bile Leaks

    Science.gov (United States)

    Pausawasadi, Nonthalee; Soontornmanokul, Tanassanee

    2012-01-01

    Endoscopic therapy by balloon dilation and placement of multiple large-bore plastic stents is the treatment of choice for benign biliary stricture. This approach is effective but it typically requires multiple endoscopic sessions given the short duration of stent patency. The endoscopic approach for treatment of bile leak involves the placement of a stent with or without biliary sphincterotomy. The self-expandable metal stent (SEMS) has traditionally been used for palliation of malignant biliary strictures given the long duration of stent patency owing to their larger stent diameter. Recently, SEMS has been used in a variety of benign biliary strictures and leaks, especially with the design of the covered self-expandable metal stent (CSEMS), which permits endoscopic-mediated stent removal. The use of CSEMS in benign biliary stricture could potentially result in a decrease in endoscopic sessions and it is technically easier when compared to placement of multiple plastic stents. However, complications such as cholecystitis due to blockage of cystic duct, stent migration, infection and pancreatitis have been reported. The potential subsegmental occlusion of contralateral intrahepatic ducts also limits the use of CSEMS in hilar stricture. Certain techniques and improvement of stent design may overcome these challenges in the future. Thus, CSEMS may be appropriate in only highly selected conditions, such as refractory benign biliary stricture, despite multiple plastic stent placement or difficult to treat bile duct stricture from chronic pancreatitis, and should not be used routinely. This review focuses on the use of fully covered self-expandable metal stent for benign biliary strictures and bile leaks. PMID:22563290

  18. [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.

  19. A fully covered self-expandable metal stent with antimigration features for benign biliary strictures : a prospective, multicenter cohort study

    NARCIS (Netherlands)

    Walter, Daisy; Laleman, Wim; Jansen, Jeroen M; van Milligen de Wit, A W M; Weusten, Bas L; van Boeckel, Petra G; Hirdes, Meike M; Vleggaar, FP; Siersema, Peter D

    2015-01-01

    BACKGROUND: Self-expandable metal stents (SEMSs) are increasingly used for the treatment of benign biliary strictures (BBSs). A new fully covered SEMS (FCSEMS) with flared ends and high conformability was designed to prevent migration of the stent. OBJECTIVE: To evaluate the efficacy of a novel

  20. A fully covered self-expandable metal stent with antimigration features for benign biliary strictures: a prospective, multicenter cohort study

    NARCIS (Netherlands)

    Walter, D.; Laleman, W.; Jansen, J.M.; Milligen de Wit, A.W. van; Weusten, B.L.; Boeckel, P.G. van; Hirdes, M.M.; Vleggaar, F.P.; Siersema, P.D.

    2015-01-01

    BACKGROUND: Self-expandable metal stents (SEMSs) are increasingly used for the treatment of benign biliary strictures (BBSs). A new fully covered SEMS (FCSEMS) with flared ends and high conformability was designed to prevent migration of the stent. OBJECTIVE: To evaluate the efficacy of a novel

  1. Extensive caustic esophageal stricture in children can be treated by serial dilatations interspersed with silicone-covered nitinol stenting

    Directory of Open Access Journals (Sweden)

    Veronica Alonso

    2016-01-01

    Full Text Available Recurrent esophageal stenosis secondary to caustic ingestion may be challenging to treat. Self-expandable esophageal stents may be an alternative to repetitive endoscopic esophageal dilatation. We report a case of a 2-year-old male child with an extensive esophageal caustic stricture successfully treated using a combination of endoscopic dilatation and stenting. After 5 months of serial balloon dilatations, three nitinol internal silicone covered self-expandable stents were placed through the patient′s gastrostomy spanning the entire esophagus. The stents were positioned using a combination of both endoscopic and fluoroscopic guidance. The procedure was repeated with only one stent 3 months later. A new stricture in the proximal esophagus needed surgical resection and anastomosis, followed by two pneumatic dilatations with progressively longer asymptomatic intervals. The results are promising with the patient able to use his own esophagus; however, this is a single case and optimal stent standing time is still to be determined.

  2. Fully Covered Metallic Stents for the Treatment of Benign Airway Stenosis

    OpenAIRE

    Dahlqvist, Caroline; Ocak, Sebahat; Gourdin, Maximilien; Dincq, Anne Sophie; Putz, Laurie; d’Odémont, Jean-Paul

    2016-01-01

    Introduction. We herein report our experience with new fully covered self-expanding metallic stents in the setting of inoperable recurrent benign tracheobronchial stenosis. Methods. Between May 2010 and July 2014, 21 Micro-Tech® FC-SEMS (Nanjing Co., Republic of Korea) were placed in our hospital in 16 patients for inoperable, recurrent (after dilatation), and symptomatic benign airway stenosis. Their medical files were retrospectively reviewed in December 2014, with focus on stent’s toleranc...

  3. 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.)

  4. 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.)

  5. Case report: ruptured aortic aneurysm into oesophagus - treatment by covered stent

    International Nuclear Information System (INIS)

    Young, N.; Tan, I.; Costa, R.

    2002-01-01

    Full text: A case report of a 70 year old man acutely presenting with a large descending thoracic aortic aneurysm, ruptured into the adjacent oesophagus. He was treated with an Aneurex covered stent (Medtronics). This patient has a long history of ischaemic heart disease, hypertension and previously treated abdominal aortic aneurysm. After diagnosis by CT, the bleeding was emergency temponaded by insertion of a Sengstaken-Blackmore tube into the oesophagus and inflated to arterial pressure. After stabilisation in ICU, it was decided that open surgery would probably prove fatal, and insertion of a covered thoracic aortic stent was performed in theatre with a femoral artery cut-down. Post-operatively the bleeding from the aortic aneurysm ceased. However, the patient has ongoing problems with large, open oesophageal ulcer with chronic ooze requiring intermittent transfusions, chronic infection with MRSA, requiring long term antibiotics, feeding via feeding gastrostomy tubes. The patient is stable 12 months after presentation. Treatment of this otherwise fatal problem by covered stent has permitted survival benefit. However, there are significant, unresolved issues of oesophageal ulcer and ongoing MRSA infection. Copyright (2002) Blackwell Science Pty Ltd

  6. Covered Metal Stenting for Malignant Lower Biliary Stricture with Pancreatic Duct Obstruction: Is Endoscopic Sphincterotomy Needed?

    Directory of Open Access Journals (Sweden)

    Kazunari Nakahara

    2013-01-01

    Full Text Available Aims. To evaluate the need for endoscopic sphincterotomy (EST before covered self-expandable metal stent (CSEMS deployment for malignant lower biliary stricture with pancreatic duct obstruction. Methods. This study included 79 patients who underwent CSEMS deployment for unresectable malignant lower biliary stricture with pancreatic duct obstruction. Treatment outcomes and complications were compared between 38 patients with EST before CSEMS deployment (EST group and 41 without EST (non-EST group. Results. The technical success rates were 100% in both the EST and the non-EST group. The incidence of pancreatitis was 2.6% in the EST, and 2.4% in the non-EST group (. The incidences of overall complications were 18.4% and 14.6%, respectively, (. Within the non-EST groups, the incidence of pancreatitis was 0% in patients with fully covered stent deployment and 3.6% in those with partially covered stent deployment (. In the multivariate analysis, younger age (, OR 12 and nonpancreatic cancer (, OR 24 were significant risk factors for overall complications after CSEMS deployment. EST was not identified as a risk factor. Conclusions. EST did not reduce the incidence of pancreatitis after CSEMS deployment in patients of unresectable distal malignant obstruction with pancreatic duct obstruction.

  7. Utility of Covered Stents for Revision of Aging Failing Synthetic Hemodialysis Grafts: A Report of Three Cases

    International Nuclear Information System (INIS)

    Silas, Anne M.; Bettmann, Michael A.

    2003-01-01

    Three aging failing hemodialysis polytetrafluoroethylene bypass shunts, average age 44 months, previously percutaneously revised with balloon angioplasty, presented with pseudoaneurysms and recurrent thrombosis. All were treated with percutaneous covered stent placement within their affected limbs. One graft was ligated 1 month after treatment for infected overlying skin ulcer, though this graft was subsequently surgically revised with interposition graft and the covered stent portion remains functional at 19 month follow-up. The 18- and 13- month follow- up of the remaining 2 patients shows that the covered stents remained patent and they are functional and being successfully and routinely punctured for dialysis. In this elderly population, the use of covered stents may prolong the functional life of failing hemodialysis bypass grafts, reducing the number of percutaneous and surgical interventions and further sparing other vascular access sites

  8. Covered Metallic Stents With an Anti-Migration Design vs. Uncovered Stents for the Palliation of Malignant Gastric Outlet Obstruction: A Multicenter, Randomized Trial

    Science.gov (United States)

    Lee, Hyuk; Min, Byung-Hoon; Lee, Jeong Hoon; Shin, Cheol Min; Kim, Younjoo; Chung, Hyunsoo; Lee, Sang Hyub

    2015-01-01

    OBJECTIVES: Previous studies reported comparable stent patency between covered self-expandable metallic stents (SEMS) and uncovered SEMS (UCS) for palliation of malignant gastric outlet obstruction (GOO). The aim of this study was to evaluate the efficacy and safety of the newly developed WAVE-covered SEMS (WCS), which has an anti-migration design, compared with UCS in gastric cancer patients with symptomatic GOO. METHODS: A total of 102 inoperable gastric cancer patients with symptomatic GOO were prospectively enrolled from five referral centers and randomized to undergo UCS or WCS placement. Stent patency and recurrence of obstructive symptoms were assessed at 8 weeks and 16 weeks after stent placement. RESULTS: At the 8-week follow-up, both stent patency rates (72.5% vs. 62.7%) and re-intervention rates (19.6% vs. 19.6%) were comparable between the WCS and the UCS groups. Both stent stenosis (2.4% vs. 8.1%) and migration rates (9.5% vs. 5.4%) were comparable between WCS and UCS groups. At the 16-week follow-up, however, the WCS group had a significantly higher stent patency rate than the UCS group (68.6% vs. 41.2%). Re-intervention rates in the WCS and UCS groups were 23.5% and 39.2%, respectively. Compared with the UCS group, the WCS group had a significantly lower stent restenosis rate (7.1% vs. 37.8%) and a comparable migration rate (9.5% vs. 5.4%). Overall stent patency was significantly longer in the WCS group than in the UCS group. No stent-associated significant adverse events occurred in either the WCS or UCS groups. In the multivariate analysis, WCS placement and chemotherapy were identified as independent predictors of 16-week stent patency. CONCLUSIONS: WCS group showed comparable migration rate and significantly more durable long-term stent patency compared with UCS group for the palliation of GOO in patients with inoperable gastric cancer. PMID:26372507

  9. Temporary placement of covered retrievable expandable nitinol stents with barbs in high-risk surgical patients with benign prostatic hyperplasia: work in progress.

    Science.gov (United States)

    Kim, Choung-Soo; Song, Ho-Young; Jeong, In Gab; Yeo, Hyun Jin; Kim, Eun-Young; Park, Jung-Hoon; Yoon, Chang Jin; Paick, Sung Hyun; Park, Sang Woo; Bae, Jae-Ik; Won, Je Hwan

    2011-10-01

    To report the use of a newly constructed, covered, retrievable, expandable nitinol stent with barbs to overcome the problem of stent migration associated with conventional covered prostatic expandable stents and to evaluate prospectively the technical feasibility and clinical effectiveness of the stents in patients with benign prostatic hyperplasia (BPH). A covered retrievable expandable nitinol stent with four barbs was placed with use of an 18-F stent delivery system in seven consecutive patients with symptomatic BPH who had high operative risks. Age range of patients was 62-83 years (mean 74 years). In cases in which the stent migrated, it was replaced with a stent with eight barbs. The stents were routinely removed 4 months after placement using a 21-F stent removal set. Stent placement was technically successful and well tolerated in six of the seven patients. The remaining patient needed a second stent placement after removal of the first stent. The stent with four barbs migrated into the urinary bladder in four patients (57%); three of these patients received a second stent with eight barbs with good results, and the fourth patient did not need further treatment because his symptoms improved. Routine removal of the stent 4 months after placement was performed in three of the seven patients with good results. Retrievable stents with eight barbs seem to overcome the problem of stent migration associated with conventional prostatic expandable stents. Preliminary results suggest that stents with barbs are both feasible and effective in patients with BPH. Copyright © 2011 SIR. Published by Elsevier Inc. All rights reserved.

  10. 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.

  11. Malignant Hilar Biliary Obstruction: Treatment by Means of Placement of a Newly Designed Y-Shaped Branched Covered Stent

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Jong Hyouk, E-mail: xell1015@naver.com; Jung, Gyoo-Sik, E-mail: gsjung@medimail.co.kr; Park, Jung Gu [Kosin University College of Medicine, Departments of Diagnostic Radiology (Korea, Republic of); Kang, Byung Chul [Ewha Womans University College of Medicine, Departments of Radiology, Mokdong Hospital (Korea, Republic of); Shin, Dong-Hoon [Kosin University College of Medicine, Departments of General Surgery (Korea, Republic of); Yun, Byung Chul; Lee, Sang Uk [Kosin University College of Medicine, Departments of Internal Medicine (Korea, Republic of)

    2016-04-15

    PurposeTo evaluate the technical feasibility and clinical efficacy of placement of a newly designed Y-shaped branched covered stent for palliative treatment of malignant hilar biliary obstruction.MethodsFrom June 2011 to September 2014, 34 consecutive patients with malignant hilar biliary obstruction underwent percutaneous placement of a Y-shaped branched covered stent for palliative treatment. Technical and clinical success, complications, cumulative patient survival, and stent patency were evaluated.ResultsStent placement was technically successful in all patients. All patients showed adequate biliary drainage on the follow-up cholangiogram. Mean serum bilirubin level (10.9 mg/dl) decreased significantly 1 week (5.7 mg/dl) and 1 month (2.6 mg/dl) after stent placement (p < 0.01). Complications associated with the procedure included hemobilia (n = 3) and biloma (n = 1). During the mean follow-up period of 225 (range 12–820) days, nine patients (26.5 %) developed stent occlusion caused by tumor overgrowth (n = 8) and sludge (n = 1). Two of them underwent coaxial placement of a second stent with good results. The median survival time was 281 days and median primary stent patency was 337 days. There were no significant differences in the patient survival and stent patency rates in relation to age, sex, or Bismuth type.ConclusionPercutaneous placement of the Y-shaped branched covered stent seems to be technically feasible and clinically effective for palliative treatment of malignant hilar biliary obstruction.

  12. 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.

  13. Fluoroscopic-guided covered metallic stent placement for gastric outlet obstruction and post-operative gastroenterostomy anastomotic stricture

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Min; Han, Young Min; Kim, Chong Soo; Lee, Sang Young; Lee, Soo Teik; Yang, Doo Hyun

    2001-07-01

    AIM: To evaluate the feasibility and safety of fluoroscopic-guided covered metallic stent placements in providing palliative care for patients with inoperable malignant gastric outlet obstruction. MATERIALS AND METHODS: Under fluoroscopic guidance, placement of self-expandable, covered stents was attempted in 20 patients with inoperable or recurrent gastric cancer (age range 36-79 years). All patients had inoperable gastric outlet obstruction, 13 with native anatomy and seven with post-operative anatomy (gastrointestinal anastomotic sites). All patients had intolerance to oral alimentation and/or vomiting after ingestion. Success was defined both technically and clinically. RESULTS: The placement of the stent was technically successful in 18 patients and failed in two patients (technical success: 90%). The cause of the technical failures was an inability to negotiate the guide wire through the obstruction sites in spite of the use of both fluoroscopic and endoscopic guidance. After stent placement, 15 patients were able to ingest at least liquids and had a markedly decreased incidence of vomiting (clinical success: 75%). During the mean follow-up of 6 weeks, there have been no stent reocclusion and no life-threatening complications except migration of two stents in one patient. CONCLUSION: Fluoroscopically guided covered metallic stent placement appears to be valuable for the palliative treatment of malignant obstruction of gastric outlet and post-operative gastrointestinal anastomoses. Lee, J.M. et al. (2001)

  14. A Novel Partially Covered Self-Expandable Metallic Stent with Proximal Flare in Patients with Malignant Gastric Outlet Obstruction.

    Science.gov (United States)

    Takahara, Naminatsu; Isayama, Hiroyuki; Nakai, Yousuke; Yoshida, Shuntaro; Saito, Tomotaka; Mizuno, Suguru; Yagioka, Hiroshi; Kogure, Hirofumi; Togawa, Osamu; Matsubara, Saburo; Ito, Yukiko; Yamamoto, Natsuyo; Tada, Minoru; Koike, Kazuhiko

    2017-07-15

    Endoscopic placement of self-expandable metal stents (SEMSs) has emerged as a palliative treatment for malignant gastric outlet obstruction (GOO). Although covered SEMSs can prevent tumor ingrowth, frequent migration of covered SEMSs may offset their advantages in preventing tumor ingrowth. We conducted this multicenter, single-arm, retrospective study at six tertiary referral centers to evaluate the safety and efficacy of a partially covered SEMS with an uncovered large-bore flare at the proximal end as an antimigration system in 41 patients with symptomatic malignant GOO. The primary outcome was clinical success, and the secondary outcomes were technical success, stent dysfunction, adverse events, and survival after stent placement. The technical and clinical success rates were 100% and 95%, respectively. Stent dysfunctions occurred in 17 patients (41%), including stent migration in nine (23%), tumor ingrowth in one (2%), and tumor overgrowth in four (10%). Two patients (5%) developed adverse events: one pancreatitis and one perforation. No procedure-related death was observed. A novel partially covered SEMS with a large-bore flare proximal end was safe and effective for malignant GOO but failed to prevent stent migration. Further research is warranted to develop a covered SEMS with an optimal antimigration system.

  15. Efficacy and safety of a new fully covered self-expandable non-foreshortening metal esophageal stent.

    Science.gov (United States)

    Dua, Kulwinder S; Latif, Sahibzada U; Yang, Juliana F; Fang, Tom C; Khan, Abdul; Oh, Young

    2014-10-01

    Fully covered esophageal self-expandable metal stents (SEMSs) are potentially removable but can be associated with high migration rates. For precise positioning, non-foreshortening SEMSs are preferred. Recently, a new fully covered non-foreshortening SEMS with anti-migration features was introduced. To evaluate the efficacy and safety of this new esophageal SEMS. Retrospective study. Single, tertiary-care center. Consecutive patients with malignant and benign strictures with dysphagia grade of ≥3 and patients with fistulas/leaks were studied. Stent placement and removal. Technical success in stent deployment/removal, efficacy in relieving dysphagia and sealing fistulas/leaks, and adverse events. Forty-three stents were placed in 35 patients (mean [± standard deviation] age 65 ± 11 years; 31 male), 24 for malignant and 11 for benign (5 strictures, 6 leaks) indications. Technical success in precise SEMS placement was 100%. The after-stent dysphagia grade improved significantly (at 1 week: 1.5 ± 0.7; at 4 weeks: 1.2 ± 0.4; baseline: 3.8 ± 0.4; P stents were removed for clinical indications, with technical success of 100%. All leaks sealed after SEMS placement and did not recur after stent removal. All benign strictures recurred after stent removal. Adverse events included migration (14%), chest pain (11%), and dysphagia from tissue hyperplasia (6%). There was no stent-related mortality. Nonrandomized, single-center study. The new esophageal SEMS was effective in relieving malignant dysphagia, allowed for precise placement, and was easily removable. It was effective in treating benign esophageal fistulas and leaks. Stent-related adverse events were acceptable. Copyright © 2014 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

  16. Treatment of a Ruptured Anastomotic Esophageal Stricture Following Bougienage with a Dacron-Covered Nitinol Stent

    International Nuclear Information System (INIS)

    Heindel, Walter; Gossmann, Axel; Fischbach, Roman; Michel, Olaf; Lackner, Klaus

    1996-01-01

    A patient suffering from esophagorespiratory fistula after bougienage of a benign stricture at the site of the anastomosis between a jejunal interposition and the esophagus was referred for interventional treatment. A prototype nitinol stent centrally covered with Dacron was implanted under regional anesthesia and fluoroscopic guidance. The self-expanding prosthesis dilated the stenosis completely and closed the fistula, with consequent improvement in respiratory and nutritional status and thus the general quality of life. The patient was able to eat and drink normally until death 3 months later due to progression of his underlying malignant disease

  17. Covered stents for endovascular repair of iatrogenic injuries of iliac and femoral arteries

    Energy Technology Data Exchange (ETDEWEB)

    Kufner, Sebastian, E-mail: kufners@dhm.mhn.de [Deutsches Herzzentrum München, Technische Universität München, Munich (Germany); Cassese, Salvatore; Groha, Philipp; Byrne, Robert A. [Deutsches Herzzentrum München, Technische Universität München, Munich (Germany); Schunkert, Heribert; Kastrati, Adnan [Deutsches Herzzentrum München, Technische Universität München, Munich (Germany); DZHK (German Centre for Cardiovascular Research), Partner Site Munich Heart Alliance, Munich (Germany); Ott, Ilka; Fusaro, Massimiliano [Deutsches Herzzentrum München, Technische Universität München, Munich (Germany)

    2015-04-15

    Background: The growing number of complex endovascular procedures is expected to increase the risk of iatrogenic injuries of peripheral arteries. A strategy of percutaneous transluminal angioplasty (PTA) with covered stent (CS) may represent a valuable alternative to open surgery. However, systematic evaluations of CS in this setting represent a scientific gap. In the present study, we investigate the procedural and clinical outcomes associated with PTA and CS implantation to repair iatrogenic injuries of peripheral arteries. Methods: All patients undergoing PTA with CS for endovascular repair of iatrogenic injuries of peripheral arteries between August 2010 and July 2013 at our Institution were retrospectively analyzed. The primary endpoint was the technical success. Secondary endpoints were in-hospital mortality and cumulative death, target lesion revascularization (TLR), amputation and major stroke at 12-month follow-up. Results: During the period of observation, a total of 30 patients underwent PTA with either self-expandable (43.3%) or balloon-expandable CS (56.7%) for iatrogenic injuries of peripheral arteries. Injuries consisted of perforation/rupture (76.7%), arteriovenous fistula (16.7%) and pseudoaneurysm (6.7%) of iliac–femoral arteries. Technical success was achieved in all cases. Median follow-up was 409 days [210–907]. The incidence of in-hospital mortality was 10.0%. At 12-month follow-up, the incidence of death, TLR, amputation and major stroke was 20.0%, 17.0%, 3.3% and 6.7%, respectively. Conclusion: The use of covered stents for endovascular repair of iatrogenic injuries of peripheral arteries shows a high technical success and may be alternative to surgery. Further studies with larger populations are needed to confirm these preliminary findings. - Highlights: • The growing number of complex endovascular procedures is expected to increase the risk of iatrogenic injuries of peripheral arteries. • Percutaneous transluminal angioplasty with

  18. Safety and efficacy of a fully covered large-diameter self-expanding metal stent for the treatment of upper gastrointestinal perforations, anastomotic leaks, and fistula

    NARCIS (Netherlands)

    van den Berg, M. W.; Kerbert, A. C.; van Soest, E. J.; Schwartz, M. P.; Bakker, C. M.; Gilissen, L. P. L.; van Hooft, J. E.

    2016-01-01

    Upper gastrointestinal perforations, fistula, and anastomotic leaks are severe conditions with high mortality. Temporary endoscopic placement of fully covered self-expanding metal stent (fSEMS) has emerged as treatment option. Stent migration is a major drawback of currently used stents. Migration

  19. Full covered self-expandable metal stents for the treatment of anastomotic leak using a silk thread.

    Science.gov (United States)

    Choi, Cheol Woong; Kang, Dae Hwan; Kim, Hyung Wook; Park, Su Bum; Kim, Su Jin; Hwang, Sun Hwi; Lee, Si Hak

    2017-07-01

    To evaluate the safety and effectiveness of fixation of the fully covered self-expandable metal stent (SEMS) placement using a silk thread for complete closure of an anastomotic leak. An anastomotic leak is a life-threatening complication after gastrectomy. Although the traditional treatment of choice was surgical re-intervention, an endoscopic SEMS can be used alternatively.During the study period, we retrospectively reviewed consecutive patients who received a modified covered SEMS capable of being fixed using a silk thread (Shim technique) due to an anastomotic leak after gastrectomy to prevent stent migration. Demographic data, stent placement and removal, clinical success, time to resolution, and complications were evaluated.A total of 7 patients underwent fully covered SEMS with a silk thread placement for an anastomotic leak after gastrectomy to treat gastric cancer. The patients' mean age was 71.3 ± 8.0 years. Man sex was predominant (85.7%). All patients' American Society of Anesthesiologists (ASA) scores were between I and III. Total gastrectomy was performed in 5 patients (71.4%) and proximal gastrectomy was performed in 2 patients (28.6%). The time between gastrectomy and stent insertion was 22.3 ± 11.1 days. The size of the leaks was 27.1 ± 11.1 mm. Technical success and complete leak closure were achieved in all patients. Stent migration was absent. All stents were removed between 4 and 6 weeks. Delayed esophageal stricture was found in 1 patient (14.2) and successfully resolved after endoscopic balloon dilation.For an anastomotic leak after gastrectomy, fully covered SEMS placement with a silk thread is an effective and safe treatment option without stent migration. The stent extraction time between 4 and 6 weeks was optimal without severe complications.

  20. Endoscopic removal of laser-cut covered self-expandable metallic biliary stents: A report of six cases.

    Science.gov (United States)

    Tanisaka, Yuki; Ryozawa, Shomei; Kobayashi, Masanori; Harada, Maiko; Kobatake, Tsutomu; Omiya, Kumiko; Iwano, Hirotoshi; Arai, Shin; Nonaka, Kouichi; Mashimo, Yumi

    2018-02-01

    Covered self-expandable metallic stents (CSEMS) may provide palliative drainage for unresectable distal malignant biliary strictures. Laser-cut CSEMS allows easy positioning due to its characteristic of minimal stent shortening. Endoscopic stent removal is sometimes recommended for recurrent biliary obstruction (RBO). However, there are no previous reports of endoscopic removal of laser-cut CSEMS. The current study presents data from 6 patients who were placed a laser-cut CSEMS for unresectable distal malignant biliary strictures, and later endoscopic stent removal was attempted for RBO at the present institute. The duration of stent placement, the procedural success rate, the procedural duration, and accidental complications were evaluated. The mean duration of stent placement was 156±37.9 days (range, 117-205). The procedural success rate was 100%. The mean procedural duration was 11.8±7.5 min (range, 5-24). No complications were reported. Laser-cut CSEMS were safely removed from all patients. The present case report is the first to demonstrate that Endoscopic stent removal of laser-cut CSEMS was safely performed.

  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. Successful treatment of an iatrogenic hepatic arteriobiliary fistula with an endobiliary covered stent graft: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Song, Hyun; Lee, Su Lim; Ku, Young Mi; Chun, Chang Woo [The Catholic Univ. of Korea, Uijeongbu (Korea, Republic of)

    2012-07-15

    Hepatic arteriobiliary fistula is a rare cause of hemobilia following percutaneous transhepatic biliary drainage for treatment of hilar cholangiocarcinoma. Hemobilia related to arterial injury is resistant to conservative treatment. Therefore, transarterial embolization after confirmation of bleeding vessels on an angiogram is generally considered as the first line of treatment to stop arterial bleeding. However, in high risk situations such as a hepatic infarction by arterial embolization, the endobiliary approach with a covered stent can be considered as an alternative treatment method. The authors report a case of iatrogenic arteriobiliary fistula in a patient with hilar cholangiocarcinoma which was successfully controlled by an endobiliary covered stent graft.

  3. Unique usage of a partially covered metal stent for drainage of a pancreatic pseudocyst via endosonography-guided transcystgastrostomy.

    Science.gov (United States)

    Nici, Anthony J; Hussain, Syed A; Kim, Sang H; Mehta, Preeti

    2012-05-01

    Pancreatic pseudocysts are frequent complications of pancreatitis episodes. The current therapeutic modalities for drainage of pancreatic pseudocysts include surgical, percutaneous, and endoscopic drainage modalities. Endosonography-assisted endoscopic drainage of these pseudocysts with the placement of multiple plastic or fully covered self-expanding biliary metal stents is becoming more commonly carried out. The present case report discusses the unique and successful drainage of a pancreatic pseudocyst with the placement of a partially covered self-expanding metal stent. © 2012 The Authors. Digestive Endoscopy © 2012 Japan Gastroenterological Endoscopy Society.

  4. Effectiveness and Safety of Endoscopic Treatment of Benign Biliary Strictures Using a New Fully Covered Self Expandable Metal Stent

    Directory of Open Access Journals (Sweden)

    Mihir S. Wagh

    2013-01-01

    Full Text Available Background. In patients with benign biliary strictures, the use of fully covered self-expandable metal stents (SEMS has been proposed as an alternative to plastic stenting, but high quality prospective data are sparse. This study was performed to evaluate the long-term effectiveness and safety of a new fully covered SEMS for benign biliary strictures. Methods. All consecutive patients with benign biliary strictures were treated with placement of a fully covered SEMS (WallFlex for 6 months. Short- and long-term stricture resolution, adverse events, and ease of stent removal were recorded. Results. 23 patients were enrolled. Stricture etiology was chronic pancreatitis (14, postorthotopic liver transplant (4, idiopathic (4, and biliary stones (1. All ERCPs were technically successful. All stents were successfully removed. Short-term stricture resolution was seen in 22/23 (96% patients. Long-term success was 15/18 (83.3%. All 3 failures were patients with biliary strictures in the setting of chronic calcific pancreatitis. Conclusions. The use of the new SEMS for the treatment of benign biliary strictures led to short-term stricture resolution in the vast majority of patients. Over a long-term followup the success rate appears favorable compared to historical results achieved with multiple plastic stenting, particularly in patients with chronic pancreatitis. The study was registered with ClinicalTrials.gov (NCT01238900.

  5. 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

  6. How to design the optimal self-expandable oesophageal metallic stents: 22 years of experience in 645 patients with malignant strictures.

    Science.gov (United States)

    Na, Han Kyu; Song, Ho-Young; Kim, Jin Hyoung; Park, Jung-Hoon; Kang, Min Kyoung; Lee, Jongjin; Oh, Se Jin

    2013-03-01

    To evaluate the clinical efficacy and safety of self-expandable metallic stent (SEMS) placement for malignant oesophageal strictures and their relationship with stent designs. Seven generations of SEMS were used to treat 645 consecutive patients with oesophageal strictures. Logistic regression models were constructed to identify predictive factors associated with complications. Stent placement was technically successful in 641 of 645 patients (99.4%). The clinical success rate was 95.5%. There were 260 (40.3%) complications after stent placement. Due to complications, 68 stents were removed; 66 of 68 stents (97.1%) were removed successfully. Stainless steel (SS) stents (odds ratio [OR] 4.18; 95% confidence interval [CI] 2.10, 8.32) and radiation therapy (RT) before stent placement (OR 4.23; CI 2.02, 8.83) were significantly associated with severe pain. Flared ends (OR 9.63; CI 3.38, 27.43), stricture length stent diameter stent migration. Polyurethane membranes were associated with more frequent tumour ingrowth than polytetrafluoroethylene (PTFE) membranes (P = 0.002). Despite the relatively high complication rate, retrievable self-expandable PTFE-covered nitinol stents equipped with a head and a tail appeared to be an effective treatment for malignant oesophageal strictures.

  7. Comparison of Technical and Clinical Outcome of Transjugular Portosystemic Shunt Placement Between a Bare Metal Stent and a PTFE-Stentgraft Device.

    Science.gov (United States)

    Lauermann, J; Potthoff, A; Mc Cavert, M; Marquardt, S; Vaske, B; Rosenthal, H; von Hahn, T; Wacker, F; Meyer, B C; Rodt, Thomas

    2016-04-01

    To analyse technical and clinical success of transjugular intrahepatic portosystemic shunt (TIPS) in patients with portal hypertension and compare a stent and a stentgraft with regard to clinical and technical outcome and associated costs. 170 patients (56 ± 12 years, 32.9% females) treated with TIPS due to portal hypertension were reviewed. 80 patients received a stent (group 1) and 83 a stentgraft (group 2), and seven interventions were unsuccessful. Technical data, periprocedural imaging, follow-up ultrasound and clinical data were analysed with focus on technical success, patency, clinical outcome and group differences. Cost analysis was performed. Portal hypertension was mainly caused by ethyltoxic liver cirrhosis with ascites as dominant symptom (80%). Technical success was 93.5% with mean portosystemic gradient decrease from 16.1 ± 4.8 to 5.1 ± 2.1 mmHg. No significant differences in technical success and portosystemic gradient decrease between the groups were observed. Kaplan-Meier analysis yielded significant differences in primary patency after 14 days, 6 months and 2 years in favour of the stentgraft. Both groups showed good clinical results without significant difference in 1-year survival and hepatic encephalopathy rate. Costs to establish TIPS and to manage 2-year follow-up with constant patency and clinical success were 8876 € (group 1) and 9394 € (group 2). TIPS is a safe and effective procedure to manage portal hypertension. Stent and stentgraft enabled good technical and clinical results with a low complication rate. Primary patency rates are clearly in favour of the stentgraft, whereas the stent was more cost effective with similar clinical results in both groups.

  8. Comparison of Technical and Clinical Outcome of Transjugular Portosystemic Shunt Placement Between a Bare Metal Stent and a PTFE-Stentgraft Device

    Energy Technology Data Exchange (ETDEWEB)

    Lauermann, J., E-mail: jostlauermann@gmail.com [Hannover Medical School, Department of Diagnostic and Interventional Radiology (Germany); Potthoff, A. [Hannover Medical School, Department of Gastroenterology, Hepatology and Endocrinology (Germany); Mc Cavert, M. [Beaumont Hospital, Department of Diagnostic and Interventional Radiology (Ireland); Marquardt, S. [Hannover Medical School, Department of Diagnostic and Interventional Radiology (Germany); Vaske, B. [Hannover Medical School, Institute of Biometry (Germany); Rosenthal, H. [Hannover Medical School, Department of Diagnostic and Interventional Radiology (Germany); Hahn, T. von [Hannover Medical School, Department of Gastroenterology, Hepatology and Endocrinology (Germany); Wacker, F.; Meyer, B. C.; Rodt, Thomas, E-mail: rodt.thomas@mh-hannover.de [Hannover Medical School, Department of Diagnostic and Interventional Radiology (Germany)

    2016-04-15

    PurposeTo analyse technical and clinical success of transjugular intrahepatic portosystemic shunt (TIPS) in patients with portal hypertension and compare a stent and a stentgraft with regard to clinical and technical outcome and associated costs.Materials and Methods170 patients (56 ± 12 years, 32.9 % females) treated with TIPS due to portal hypertension were reviewed. 80 patients received a stent (group 1) and 83 a stentgraft (group 2), and seven interventions were unsuccessful. Technical data, periprocedural imaging, follow-up ultrasound and clinical data were analysed with focus on technical success, patency, clinical outcome and group differences. Cost analysis was performed.ResultsPortal hypertension was mainly caused by ethyltoxic liver cirrhosis with ascites as dominant symptom (80 %). Technical success was 93.5 % with mean portosystemic gradient decrease from 16.1 ± 4.8 to 5.1 ± 2.1 mmHg. No significant differences in technical success and portosystemic gradient decrease between the groups were observed. Kaplan–Meier analysis yielded significant differences in primary patency after 14 days, 6 months and 2 years in favour of the stentgraft. Both groups showed good clinical results without significant difference in 1-year survival and hepatic encephalopathy rate. Costs to establish TIPS and to manage 2-year follow-up with constant patency and clinical success were 8876 € (group 1) and 9394 € (group 2).ConclusionTIPS is a safe and effective procedure to manage portal hypertension. Stent and stentgraft enabled good technical and clinical results with a low complication rate. Primary patency rates are clearly in favour of the stentgraft, whereas the stent was more cost effective with similar clinical results in both groups.

  9. Endoscopic suture fixation is associated with reduced migration of esophageal fully covered self-expandable metal stents (FCSEMS).

    Science.gov (United States)

    Wright, Andrew; Chang, Andrew; Bedi, Aarti Oza; Wamsteker, Erik-Jan; Elta, Grace; Kwon, Richard S; Carrott, Phillip; Elmunzer, B Joseph; Law, Ryan

    2017-09-01

    Esophageal fully covered self-expandable metal stents (FCSEMS) are indicated for the management of benign and malignant conditions of the esophagus including perforations, leaks, and strictures. FCSEMS are resistant to tissue ingrowth and are removable; however, stent migration occurs in 30-55% of cases. Endoscopic suture fixation of FCSEMS has been utilized to decrease the risk of stent migration though data supporting this practice remain limited. The primary aim of this study was to compare clinical outcomes and migration rate of patients who underwent placement of esophageal FCSEMS with and without endoscopic suture fixation. Our single-center, retrospective, cohort study includes patients who underwent esophageal FCSEMS placement with and without endoscopic suture fixation between January 1, 2012, and November 11, 2015. Baseline patient characteristics, procedural details, and clinical outcomes were abstracted. Logistic regression was performed to identify clinical and technical factors associated with outcomes and stent migration. A total of 51 patients underwent 62 FCSEMS placements, including 21 procedures with endoscopic suture fixation and 41 without. Suture fixation was associated with reduced risk of stent migration (OR 0.13, 95% CI 0.03-0.47). Prior stent migration was associated with significantly higher risk of subsequent migration (OR 6.4, 95% CI 1.6-26.0). Stent migration was associated with lower likelihood of clinical success (OR 0.21, 95% CI 0.06-0.69). There was a trend toward higher clinical success among patients undergoing suture fixation (85.7 vs. 60.9%, p = 0.07). Endoscopic suture fixation of FCSEMS was associated with a reduced stent migration rate. Appropriate patient selection for suture fixation of FCSEMS may lead to reduced migration in high-risk patients.

  10. Pseudoaneurysm of the Internal Carotid Artery: Treatment with a Covered Stent

    International Nuclear Information System (INIS)

    Scavee, Vincent; Wispelaere, Jean-Francois de; Mormont, Eric; Coulier, Bruno; Trigaux, Jean-Paul; Schoevaerdts, Jean-Claude

    2001-01-01

    Dissection of the cervical segment of the internal carotid artery may occur spontaneously or after trauma. We report the management of a 53-year-old right-handed man with progressive dizziness and neck pain 6 weeks after a motor vehicle collision. The clinical and neurologic examinations were normal. The CT scan led to the diagnosis of a pseudoaneurysm of the right internal carotid artery near the skull base. We successfully treated this post-traumatic lesion with a covered stent. The patient underwent the endovascular procedure under general anesthesia and transcranial Doppler monitoring. No neurologic event was observed. Obliteration of the pseudoaneurysm with preservation of the carotid artery was achieved. The patient was discharged from the hospital 72 hr later with no complications. Clinical and imaging follow-up at 6 months was unremarkable

  11. Catalytic activity of hydrophobic Pt/C/PTFE catalysts of different PTFE content for hydrogen-water liquid exchange reaction

    International Nuclear Information System (INIS)

    Hu Sheng; Xiao Chengjian; Zhu Zuliang; Luo Shunzhong; Wang Heyi; Luo Yangming; Wang Changbin

    2007-01-01

    10%Pt/C catalysts were prepared by liquid reduction method. PTFE and Pt/ C catalysts were adhered to porous metal and hydrophobic Pt/C/PTFE catalysts were prepared. The structure and size of Pt crystal particles of Pt/C catalysts were analyzed by XRD, and their mean size was 3.1 nm. The dispersion state of Pt/C and PTFE was analyzed by SEM, and they had good dispersion mostly, but PTFE membrane could be observed on local parts of Pt/C/PTFE surface. Because of low hydrophobicity, Pt/C/ PTFE catalysts have low activity when the mass ratio of PTFE and Pt/C is 0.5: 1, and their catalytic activity increases markedly when the ratio is 1:1. When the ratio increases again, more Pt active sites would be covered by PTFE and interior diffusion effect would increase, which result in the decrease of catalytic activity of Pt/C/PTFE. By PTFE pretreatment of porous metal carrier, the activity of Pt/C/PTFE catalysts decreases when the mass ratio of PTFE and Pt/C is 0.5:1, and their activity decreases when the mass ratio is 1:1. (authors)

  12. Recanalization of an Occluded Intrahepatic Portosystemic Covered Stent via the Percutaneous Transhepatic Approach

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Chih Yang; Liang, Po Chin [National Taiwan University Hospital, Taipei (China)

    2010-08-15

    A 41-year-old woman with liver cirrhosis had recurrent portal hypertension and bleeding from esophageal varices due to complete occlusion of a previously inserted transjugular intrahepatic portosystemic shunt stent. Because recanalization of the stent by the transjugular approach was unsuccessful, ultrasound-guided entry to the splenic vein and portal vein was used. After catheter-directed intrathrombus thrombolysis, successful opening of the stent was achieved and a stent was placed. We herein report a rare case in which thrombolysis and recanalization of a TIPS stent were performed via a percutaneous transhepatic approach

  13. Treatment of traumatic internal carotid artery pseudoaneurysms with willis covered stents: a midterm follow-up result

    International Nuclear Information System (INIS)

    Wang Wu; Li Minghua; Li Yongdong; Gu Binxian; Fang Chun; Tan Huaqiao; Wang Ju; Zhang Peilei

    2010-01-01

    Objective: To evaluate the efficacy and mid-term follow-up results of endovascular treatment with Willis covered stent for traumatic pseudoaneurysms located in the internal carotid artery (ICA). Methods: ICA angiography was performed in 38 patients with traumatic brain and neck injury. Of the 38 patients, 13 delayed traumatic pseudoaneurysms were found. All the pseudoaneurysms were treated with Willis covered stents. Follow-up angiography was performed at 1, 3, 6 and 12 months after the procedure, and the results were categorized as complete or incomplete occlusion. Clinical manifestations were graded as full recovery, improvement, unchanged and aggravation. Results: Willis covered stent placement was technically successful in all traumatic pseudoaneurysms. No procedure-related complications occurred. The initial angiographic results showed a complete occlusion in 9 patients, and an incomplete occlusion in 4. The angiographic follow-up within 3-12 months exhibited a complete occlusion in 12 patients and the parent arteries remained patency in all patients. The clinical follow-up observation demonstrated that full recovery was obtained in 11 patients, clinical improvement in one, and unchanged condition in one. No morbidity or mortality occurred. Conclusion: Willis covered stent implantation is a feasible and practical treatment for traumatic pseudoaneurysms located in the ICA. This technique can well preserve the parent artery with excellent therapeutic results. (authors)

  14. Covered self-expandable metal stents in pancreatic malignancy regardless of resectability: a new concept validated by a decision analysis.

    Science.gov (United States)

    Kahaleh, M; Brock, A; Conaway, M R; Shami, V M; Dumonceau, J M; Northup, P G; Tokar, J; Rich, T A; Adams, R B; Yeaton, P

    2007-04-01

    The current treatment model for the management of malignant biliary obstruction is to place a plastic stent for unstaged pancreatic cancer. In patients with unresectable disease but a life expectancy of more than 6 months, self-expandable metal stents (SEMS) are favored because of their more prolonged patency. We analyzed the efficacy and cost-effectiveness of covered SEMS (CSEMS) in patients with pancreatic cancer and distal biliary obstruction without regard to surgical resectability. Between March 2001 and March 2005, 101 consecutive patients with obstructive jaundice secondary to pancreatic cancer underwent placement of a CSEMS. Patients with resectable tumor were offered pancreaticoduodenectomy. A model was developed to compare the costs of CSEMS and polyethylene and DoubleLayer stents. A total of 21 patients underwent staging laparoscopy, of whom 16 had a resection (76%). The 85 patients who did not have a resection had a mean survival of 5.9 months (range 1-25 months) and a mean CSEMS patency duration of 5.5 months (range 1-16 months). Life-table analysis demonstrated CSEMS patency rates of 97% at 3 months, 85% at 6 months, and 68% at 12 months. In a cost model that accounted for polyethylene and DoubleLayer stent malfunction and surgical resections, initial CSEMS placement (3177 euros per patient) was a less costly intervention than either DoubleLayer stent placement (3224 euros per patient) or polyethylene stent placement with revision (3570 euros per patient). Covered SEMS are an effective treatment for distal biliary obstructions caused by pancreatic carcinoma. Their prolonged patency and removability makes them an attractive option for biliary decompression, regardless of resectability. The strategy of initial covered SEMS placement might be the most cost-effective strategy in these patients.

  15. Covered versus Uncovered Self-Expandable Metal Stents for Managing Malignant Distal Biliary Obstruction: A Meta-Analysis.

    Science.gov (United States)

    Li, Jinjin; Li, Tong; Sun, Ping; Yu, Qihong; Wang, Kun; Chang, Weilong; Song, Zifang; Zheng, Qichang

    2016-01-01

    To compare the efficacy of using covered self-expandable metal stents (CSEMSs) and uncovered self-expandable metal stents (UCSEMSs) to treat objective jaundice caused by an unresectable malignant tumor. We performed a comprehensive electronic search from 1980 to May 2015. All randomized controlled trials comparing the use of CSEMSs and UCSEMSs to treat malignant distal biliary obstruction were included. The analysis included 1417 patients enrolled in 14 trials. We did not detect significant differences between the UCSEMS group and the CSEMS group in terms of cumulative stent patency (hazard ratio (HR) 0.93, 95% confidence interval (CI) 0.19-4.53; p = 0.93, I2 = 0%), patient survival (HR 0.77, 95% CI 0.05-10.87; p = 0.85, I2 = 0%), overall stent dysfunction (relative ratio (RR) 0.85, M-H, random, 95% CI 0.57-1.25; p = 0.83, I2 = 63%), the overall complication rate (RR 1.26, M-H, fixed, 95% CI 0.94-1.68; p = 0.12, I2 = 0%) or the change in serum bilirubin (weighted mean difference (WMD) -0.13, IV fixed, 95% CI 0.56-0.3; p = 0.55, I2 = 0%). However, we did detect a significant difference in the main causes of stent dysfunction between the two groups. In particular, the CSEMS group exhibited a lower rate of tumor ingrowth (RR 0.25, M-H, random, 95% CI 0.12-0.52; p = 0.002, I2 = 40%) but a higher rate of tumor overgrowth (RR 1.76, M-H, fixed, 95% CI 1.03-3.02; p = 0.04, I2 = 0%). Patients with CSEMSs also exhibited a higher migration rate (RR 9.33, M-H, fixed, 95% CI 2.54-34.24; p = 0.008, I2 = 0%) and a higher rate of sludge formation (RR 2.47, M-H, fixed, 95% CI 1.36-4.50; p = 0.003, I2 = 0%). Our meta-analysis indicates that there is no significant difference in primary stent patency and stent dysfunction between CSEMSs and UCSEMSs during the period from primary stent insertion to primary stent dysfunction or patient death. However, when taking further management for occluded stents into consideration, CSEMSs is a better choice for patients with malignant biliary

  16. Temporary placement of covered self-expandable metallic stents in the management of benign biliary strictures.

    Science.gov (United States)

    Yasuda, Ichiro; Mukai, Tsuyoshi; Doi, Shinpei; Tomita, Eiichi; Moriwaki, Hisataka

    2012-05-01

    Currently, endoscopic intervention is widely attempted as the first-line treatment of benign biliary strictures because of its convenience and low morbidity. Plastic tube stents (PS) are usually used for such treatment; however, covered self-expandable metallic stents (C-SEMS) are becoming more commonly used at some institutions. The temporary placement of C-SEMS may lead to better outcomes because of their larger diameter and, therefore, better dilation of the stricture, especially in refractory cases. The aim of the present study was to evaluate the efficacy of the temporary placement of C-SEMS in the management of benign biliary strictures. We retrospectively reviewed our endoscopic retrograde cholangiopancreatography (ERCP) database (May 1996 to December 2010), and extracted the data of patients who underwent endoscopic treatment for benign biliary strictures. Then, the follow-up data from patient charts were reviewed to determine the long-term outcomes of those procedures. All patients (n = 56) initially had a PS placed, with or without balloon dilation. However, C-SEMS placement was later attempted in 12 patients because the stricture was refractory to placement of the PS. During their follow-up periods, two patients died of unrelated diseases after 15 and 17 months, and another two still had the C-SEMS in place after 9 and 50 months. In the remaining eight patients, the C-SEMS was removed after a median placement period of 6 months (range, 2-15). Seven patients in this group have not experienced a recurrence at a median follow-up time of 48 months. However, in one patient, stenosis did recur 8 months after the C-SEMS was removed. Temporary placement of C-SEMS can be a treatment option for benign biliary strictures, especially in refractory cases. © 2012 The Authors. Digestive Endoscopy © 2012 Japan Gastroenterological Endoscopy Society.

  17. [The application of Y-shaped self-expandable covered metal stents in the thoracostomach-airway fistula: a single center, 11 years experience].

    Science.gov (United States)

    Fang, Yi; Li, Tengfei; Han, Xinwei; Wu, Gang; Ren, Jianzhuang; Ren, Kewei; Lu, Huibin; Zhang, Quanhui; Li, Zongming

    2015-08-01

    To investigate the clinical feasibility and efficacy of Y-shaped self-expandable covered metal stents (Y-stents) in the management of thoracostomach-airway fistula. Retrospective analysis was performed for 108 patients treated for thoracostomach-airway fistula with Y-shaped self-expandable coated metal stents between April 2003 and October 2014. Y-stents were designed based on the dimensions of trachea and bronchus and sites of the fistula and then were inserted under DSA monitoring. There were 65 cases with single big Y-stent placement, 26 cases with single small Y-stent placement, 23 cases with double Y-stents placement, and 1 case with 3 Y-stents placement. Stent implantation was successfully accomplished with single manipulation in all patients. Complete occlusion of the fistula was obtained in 104 patients after the primary manipulation, and 4 patients required a secondary manipulation where a double Y-stents was inserted because of failure of primary manipulate. Ninety-two patients completed the follow-up , while 16 were lost. Fifty-nine patients died while 33 were alive with marked improvement in their quality of life. The placement of Y-stents can effectively occlude the thoracostomach-airway fistula in patients who had had the esophageal tumors resected. The technique is not only feasible but reliable to improve the quality of life of the patients.

  18. Pancreatic Necrosectomy Through a Novel Double-flange Lumen-apposing Covered Metal Stent (Video

    Directory of Open Access Journals (Sweden)

    Andres Sanchez-Yague

    2014-12-01

    A double flange lumen apposing FC-SEMS used as a port for necrosectomy significantly improves management of walled-off pancreatic necrosis. Placement of this stents should be considered when multiple necrosectomy sessions are anticipated. Procedure time can be significantly decreased using a catheter that combines a cautery tip and stent delivery system.

  19. Argon Plasma Coagulation Combined with Covered Stent Placement for Management of Tracheobronchial Stenoses/occlusions as well as Esophagorespiratory Fistulas

    Directory of Open Access Journals (Sweden)

    Hongwu WANG

    2010-09-01

    Full Text Available Background and objective It is a complex problem and difficult treatment for tracheobronchial stenoses/occlusions involving in carina. The aim of this study is to investigate the feasibility and efficiency of argon plasma coagulation (APC and bifurcated covered Z-type stents (CZTS placement for the treatment of tracheobronchus stenoses and esophagorespiratory fistula (ERF. Methods Thirty-two cases with airway disorders were retrospectively reviewed for the treatment of APC and CZTS placement. Under the bronchoscopic guidance, APC was first given in patients with airway stenoses, then CZTS was placed under the fluoroscopic and flexible bronchoscopic guidance either with airway stenoses or ERF. Results APC was first given in 19 patients with airway stenoses. Airway structures were significantly improved after APC procedure (57.4%-72.1% before APC vs 12.8%-25.8% after APC. Thirty-two CZTS were technically successfully placed in 30 out of 32 cases involving in carinal bifurcation. After APC and stent placement, short breath index was significantly reduced and karnofsky physical score (KPS increased obviously. The endobronchial defects were successfully palliated with bifurcated CZTS placed under fluoroscopy and flexible bronchoscopy in 12 out of 13 patients with ERFs. There is no bleeding introprocedure. Mucous retention was very common in all types of the stents less than 2 weeks after stenting, which required debridement by bronchoscopy and could be prevented by normal saline solution nebulizations. Granuloma developed at the ends of stents after 1 month of stenting which all of them were treated successfully with APC and CO2 cryosurgery. Conclusion Utilization of APC and retrieval bifurcated CZTS placement is a simple and safe protocol for the management of airway complex stenoses involving the tracheal carina and ERF.

  20. 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

  1. Percutaneous unilateral biliary metallic stent placement in patients with malignant obstruction of the biliary hila and contralateral portal vein steno-occlusion

    Energy Technology Data Exchange (ETDEWEB)

    Son, Rak Chae; Gwon, Dong Il; Ko, Heung Kyu; Kim, Jong Woo; Ko, Gi Young [Dept. of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    2015-06-15

    To investigate the outcomes of percutaneous unilateral metallic stent placement in patients with a malignant obstruction of the biliary hila and a contralateral portal vein steno-occlusion. Sixty patients with a malignant hilar obstruction and unilobar portal vein steno-occlusion caused by tumor invasion or preoperative portal vein embolization were enrolled in this retrospective study from October 2010 to October 2013. All patients were treated with percutaneous placement of a biliary metallic stent, including expanded polytetrafluoroethylene (ePTFE)-covered stents in 27 patients and uncovered stents in 33 patients. A total of 70 stents were successfully placed in 60 patients. Procedural-related minor complications, including self-limiting hemobilia (n = 2) and cholangitis (n = 4) occurred in six (10%) patients. Acute cholecystitis occurred in two patients. Successful internal drainage was achieved in 54 (90%) of the 60 patients. According to a Kaplan-Meier analysis, median survival time was 210 days (95% confidence interval [CI], 135-284 days), and median stent patency time was 133 days (95% CI, 94-171 days). No significant difference in stent patency was observed between covered and uncovered stents (p = 0.646). Stent dysfunction occurred in 16 (29.6%) of 54 patients after a mean of 159 days (range, 65-321 days). Unilateral placement of ePTFE-covered and uncovered stents in the hepatic lobe with a patent portal vein is a safe and effective method for palliative treatment of patients with a contralateral portal vein steno-occlusion caused by an advanced hilar malignancy or portal vein embolization. No significant difference in stent patency was detected between covered and uncovered metallic stents.

  2. Reversal of Transjugular Intrahepatic Portosystemic Shunt (TIPS)-Induced Hepatic Encephalopathy Using a Strictured Self-Expanding Covered Stent

    International Nuclear Information System (INIS)

    Cox, Mitchell W.; Soltes, George D.; Lin, Peter H.; Bush, Ruth L.; Lumsden, Alan B.

    2003-01-01

    Hepatic encephalopathy is a known complication following percutaneous transjugular intrahepatic portosystemic shunt (TIPS) placement. We describe herein a simple and effective strategy of TIPS revision by creating an intraluminal stricture within a self-expanding covered stent, which is deployed in the portosystemic shunt to reduce the TIPS blood flow. This technique was successful in reversing a TIPS-induced hepatic encephalopathy in our patient

  3. Covered Bronchial Stent Insertion to Manage Airway Obstruction with Hemoptysis Caused by Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sae Ah; Kim, Do Hyeong [Dankook University College of Medicine, Dankook University Hospital, Cheonan (Korea, Republic of); Jen, Gyeong Sik [Bundang CHA General Hospital, CHA University, Seongnam (Korea, Republic of)

    2012-07-15

    Malignant airway obstruction and hemoptysis are common in lung cancer patients. Recently, airway stent is commonly used to preserve airway in malignant airway obstruction. Hemoptysis can be managed through various methods including conservative treatment, endobronchial tamponade, bronchoscopic intervention, embolization and surgery. In our case studies, we sought to investigate the effectiveness of airway stents for re-opening the airway as well as tamponade effects in four patients with malignant airway obstruction and bleeding caused by tumors or lymph node invasions.

  4. EW-7197 eluting nano-fiber covered self-expandable metallic stent to prevent granulation tissue formation in a canine urethral model.

    Directory of Open Access Journals (Sweden)

    Kichang Han

    Full Text Available To evaluate an EW-7197-eluting nanofiber-covered stent (NFCS for suppressing granulation tissue formation after stent placement in a canine urethral model.All experiments were approved by the committee of animal research. A total of 12 NFCSs were placed in the proximal and distal urethras of six dogs. Dogs were divided into two groups with 3 dogs each. The control stent (CS group received NFCSs and the drug stent (DS group received EW-7197 (1000 μg-eluting NFCSs. All dogs were sacrificed 8 weeks after stent placement Histologic findings of the stented urethra were compared using the Mann-Whitney U test.Stent placement was technically successful in all dogs without procedure-related complications. On urethrographic analysis, the mean luminal diameter was significantly larger in the DS group than in the CS group at 4 and 8 weeks after stent placement (all p 0.05.The EW-7197-eluting NFCS is effective and safe for suppressing granulation tissue formation after stent placement in a canine urethral model.

  5. 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.

  6. Sustained Benefit at 2 Years for Covered Stents Versus Bare-Metal Stents in Long SFA Lesions: The VIASTAR Trial

    Energy Technology Data Exchange (ETDEWEB)

    Lammer, Johannes, E-mail: jlammer@gmx.at, E-mail: johannes.lammer@meduniwien.ac.at [Medical University Vienna, The Department of Cardiovascular and Interventional Radiology, Department of Biomedical Imaging and Image-guided Therapy (Austria); Zeller, Thomas, E-mail: thomas.zeller@universitaets-herzzentrum.de [Universitaets-Herzzentrum Freiburg-Bad Krozingen, Department of Angiology (Germany); Hausegger, Klaus A., E-mail: klaus.hausegger@lkh-klu.at [Klinikum Klagenfurt, The Department of Diagnostic and Interventional Radiology (Austria); Schaefer, Philipp J., E-mail: jp.schaefer@rad.uni-kiel.de [University Clinics Schleswig-Holstein, The Department of Radiology (Germany); Gschwendtner, Manfred, E-mail: manfred.gschwendtner@elisabethinen.or.at [Elisabethinen Hospital, The Department of Diagnostic and Interventional Radiology (Austria); Mueller-Huelsbeck, Stefan, E-mail: muehue@diako.de [Diakonissen Hospital, The Department of Diagnostic and Interventional Radiology (Germany); Rand, Thomas, E-mail: thomas.rand@wienkav.at [Hietzing Hospital, The Department of Radiology (Austria); Funovics, Martin, E-mail: martin.funovics@meduniwien.ac.at; Wolf, Florian, E-mail: florian.wolf@meduniwien.ac.at [Medical University Vienna, The Department of Cardiovascular and Interventional Radiology, Department of Biomedical Imaging and Image-guided Therapy (Austria); Rastan, Aljoscha, E-mail: aljoscha.rastan@universitaets-herzzentrum.de [Universitaets-Herzzentrum Freiburg-Bad Krozingen, Department of Angiology (Germany); Gschwandtner, Michael, E-mail: michael.gschwandtner@meduniwien.ac.at [Medical University Vienna, The Department of Angiology (Austria); Puchner, Stefan, E-mail: stefan.puchner@meduniwien.ac.at [Medical University Vienna, The Department of Cardiovascular and Interventional Radiology, Department of Biomedical Imaging and Image-guided Therapy (Austria); and others

    2015-02-15

    PurposeThe hypothesis that covered stents are superior to bare-metal stents (BMS) in long femoropopliteal artery disease was tested. The one-year results of the VIASTAR trial revealed a patency benefit of covered stents in the treatment-per-protocol (TPP) analysis only.MethodsA prospective, randomized, single-blind, multicenter study evaluated 141 patients with symptomatic peripheral arterial disease (PAD) after treatment with heparin-bonded covered stents (VIABAHN{sup ®} Endoprosthesis) or BMS. Clinical outcomes and patency rates were assessed at 1, 6, 12, and 24 months. Mean lesion length was 19.0 ± 6.3 cm in the VIABAHN{sup ®} versus 17.3 ± 6.6 cm in the BMS group.ResultsThe 24-month primary patency rates in the VIABAHN{sup ®} and BMS group were: intention-to-treat 63.1 (95 % CI 0.52–0.76) versus 41.2 % (95 % CI 0.29–0.57; log rank p = 0.04) and TPP 69.4 (95 % CI 0.58–0.83) versus 40.0 % (95 % CI 0.28–0.56; log rank p = 0.004). Freedom from target-lesion-revascularization (TLR) was 79.4 (95 % CI 0.70–0.90) versus 73.0 % (95 % CI 0.63–0.85) for VIABAHN{sup ®} versus BMS (log rank p = 0.37). For the TPP group in lesions ≥20 cm, the 24-month patency rates were 65.2 (95 % CI 0.50–0.85) versus 26.7 % (95 % CI 0.12–0.59; log rank p = 0.004) for VIABAHN{sup ®} versus BMS, and freedom from TLR was 80.0 (95 % CI 0.68–0.94) versus 61.9 % (95 % CI 0.44–0.87; log rank p = 0.13). The ankle brachial index was 0.89 ± 0.18 versus 0.91 ± 0.17 (p = 0.76) at 24-month in the VIABAHN{sup ®} versus the BMS group, respectively.ConclusionAt 24-month, this trial in PAD patients with long femoropopliteal lesions demonstrated a significantly improved primary patency rate for heparin-bonded covered stents compared to BMS, however, without a significant impact on clinical outcomes and TLR rate (Reg. Nr. ISRCTN48164244)

  7. Percutaneous Endoluminal Stent-Graft Repair of an Old Traumatic Femoral Arteriovenous Fistula

    International Nuclear Information System (INIS)

    Uflacker, Renan; Elliott, Bruce M.

    1996-01-01

    A stent-graft was custom made to close a high-flow traumatic arteriovenous fistula of the left superficial femoral artery, present for 30 years, in a 60-year-old man with congestive heart failure and ischemic ulceration in the left foot. A balloon expandable Palmaz stent (P394; 2.5 mm x 3.9 cm) was covered with a polytetrafluoroethylene (PTFE) graft and was inserted percutaneously through an 11 Fr vascular sheath. Follow-up Doppler ultrasound at 6 months demonstrated occlusion of the arteriovenous fistula, patency of the artery, and luminal integrity of the artery and vein

  8. 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

  9. 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.

  10. Evaluation of the small intestinal submucosa covered stent in preventing restenosis after percutaneous transluminal angioplasty in the swine

    International Nuclear Information System (INIS)

    Wang Xiaobai; Li Jinglei; Zhang Hong; Zhang Yan

    2012-01-01

    Objective: To compare the performance of small intestinal submucosa (SIS)-covered endografts (SCEs) to bare nitinol stents (BSs) in injured swine iliac arteries. Materials and methods: Twenty-eight nitinol stents were used: 14 externally SCEs and 14 BSs. Devices were implanted in each side of balloon-injured external iliac arteries of 14 swine via carotid approach. Arteriograms were obtained before and after implantation and before animal sacrifice at 4, 8, and 12 weeks. Histopathological and electron microscopy studies of explanted specimens were performed. Results: Implantation of all SCEs and BSs was technically successful, but one SCE and one BS were obstructed at 8 weeks after implantation. At sacrifice, the other 26 stents were patent, with angiogram showing no significant different luminal narrowing between SCEs and BSs. Proliferating cell nuclear antigen (PCNA) immunohistochemistry examination revealed that the percentage of PCNA(+) cells were lower in SCEs (p < 0.05). Additionally, histomorphological analysis indicated that the neointima area and percentage of narrowing area were greater in SCEs, but there was no statistical significance. Greater endothelial cell count in SCEs than in BSs per visual field at 4000 times magnification by scanning electron microscope (p < 0.05). Conclusion: Compared to BSs, no definite decrease of neointima and restenosis was found in SCEs in the present study. However, it is effective in promoting endothelial regeneration and strengthening endothelial function.

  11. Novel deployment of a covered duodenal stent in open surgery to facilitate closure of a malignant duodenal perforation

    Directory of Open Access Journals (Sweden)

    Psaila Josephine

    2009-10-01

    Full Text Available Abstract Background Its a dilemma to attempt a palliative procedure to debulk the tumour and/or prevent future obstructive complications in a locally advanced intra abdominal malignancy. Case presentation A 38 year old Vietnamese man presented with a carcinoma of the colon which had invaded the gallbladder and duodenum with a sealed perforation of the second part of the duodenum. Following surgical exploration, it was evident that primary closure of the perforated duodenum was not possible due to the presence of unresectable residual tumour. Conclusion We describe a novel technique using a covered duodenal stent deployed at open surgery to aid closure of a malignant duodenal perforation.

  12. Partially covered versus uncovered self-expandable nitinol stents with anti-migration properties for the palliation of malignant distal biliary obstruction: A randomized controlled trial.

    Science.gov (United States)

    Yang, Min Jae; Kim, Jin Hong; Yoo, Byung Moo; Hwang, Jae Chul; Yoo, Jun Hwan; Lee, Ki Seong; Kang, Joon Koo; Kim, Soon Sun; Lim, Sun Gyo; Shin, Sung Jae; Cheong, Jae Youn; Lee, Kee Myung; Lee, Kwang Jae; Cho, Sung Won

    2015-01-01

    Covered self-expandable metal stents (SEMSs) are increasingly used as alternatives to uncovered SEMSs for the palliation of inoperable malignant distal biliary obstruction to counteract tumor ingrowth. We aimed to compare the outcomes of partially covered and uncovered SEMSs with identical mesh structures and anti-migration properties, such as low axial force and flared ends. One hundred and three patients who were diagnosed with inoperable malignant distal biliary obstruction between January 2006 and August 2013 were randomly assigned to either the partially covered (n = 51) or uncovered (n = 52) SEMS group. There were no significant differences in the cumulative stent patency, overall patient survival, stent dysfunction-free survival and overall adverse events, including pancreatitis and cholecystitis, between the two groups. Compared to the uncovered group, stent migration (5.9% vs. 0%, p = 0.118) and tumor overgrowth (7.8% vs. 1.9%, p = 0.205) were non-significantly more frequent in the partially covered group, whereas tumor ingrowth showed a significantly higher incidence in the uncovered group (5.9% vs. 19.2%, p = 0.041). Stent migration in the partially covered group occurred only in patients with short stenosis of the utmost distal bile duct (two in ampullary cancer, one in bile duct cancer), and did not occur in any patients with pancreatic cancer. For the palliation of malignant distal biliary obstruction, endoscopic placement of partially covered SEMSs with anti-migration designs and identical mesh structures to uncovered SEMSs failed to prolong cumulative stent patency or reduce stent migration.

  13. Predictors of outcomes in patients undergoing covered and uncovered self-expandable metal stent placement for malignant gastric outlet obstruction: a multicenter study.

    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

    2017-02-01

    Uncovered self-expandable metal stents (U-SEMSs) and covered self-expandable metal stents (C-SEMSs) are available for palliative therapy for malignant gastric outlet obstruction (GOO). However, clinical differences and indications between the 2 types of SEMSs have not been elucidated. We retrospectively compared 126 patients with U-SEMS and 126 patients with C-SEMSs with regard to clinical outcome and factors predictive of clinical improvement after SEMSs placement. No significant difference was observed between the U-SEMS and C-SEMS groups with respect to technical success, clinical success, GOO score, or time to stent dysfunction. Stent migration was significantly more frequent in patients with C-SEMSs (U-SEMSs, .79%; C-SEMSs, 8.73%; P = .005). Karnofsky performance status, chemotherapy, peritoneal dissemination, and stent expansion ≤ 30% were associated significantly with poor GOO score improvement in multivariable analyses, but stent type was not (P = .213). In subgroup analyses, insufficient (≤30%) stent expansion was an independent factor in patients with U-SEMSs (P = .041) but not C-SEMSs. In the insufficient stent expansion subgroup, C-SEMSs was associated significantly with superior clinical improvement compared with U-SEMSs (P = .01). Insufficient stent expansion was observed more frequently in patients with GI obstruction because of anastomotic sites or metastatic cancer (44.8% [13/29], P = .001). No clinical difference, apart from stent migration, was observed between patients with U-SEMSs and C-SEMSs. GI obstruction because of an anastomotic site or metastatic cancer may be an indication for C-SEMS use to improve oral intake after SEMSs placement. Copyright © 2017 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

  14. 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.

  15. Use of the covered Y-shaped metallic stent in the treatment of airway stenoses involving the lower trachea and the tracheal carina: preliminary clinical study

    International Nuclear Information System (INIS)

    Yang Ruimin; Li Fenbao; Zhang Mingqiu; Wu Gang; Han Xinwei

    2007-01-01

    Objective: To describe a new kind of Y-shaped metallic stent delivery system and evaluate its feasibility and preliminary effect for managing multiple airway stenoses involving the lower trachea and the tracheal carina. Methods: The Y-shaped metallic stent delivery system consisted of three-tier structure. The inner-tier was composed of four parallel guiding tubes, which was used for two guidewires and two threads passing through, the middle-tier was delivery catheter, which contained the four guiding tubes, and the outer-tier was introducer sheath. Under the fluoroscopic guidance, 15 patients with multiple stenoses involving the lower trachea and the tracheal carina were treated with the new covered self-expandable Y-shaped metallic stents. Results: Stent placement in the tracheo-bronchial tree was technically successful in all patients with obliteration of the dyspnea immediately after stent placement, and SaO2 was increased form preoperative 75%-89% to postoperative 96%-99%. During follow-up a period of 3-58 weeks (M 22 weeks), all stenosis were resolved without stent-related complications, and the general physical of all 15 patents was improved with no occurrence of obviously dyspnea and bleeding. Karnofsky performance status (KPS) was improved from preoperative 26%-45% to postoperative 72%-95%. Five patients died of the following causes unrelated to stent insertion: multiple organ failure (n=3), cachexia (n=1) and pulmonary infection caused by gastrobronehial fistula (n=1), and the remaining 10 patients were alive with no evidence of dyspnea at the time of this report. Conclusion: Deployment of the covered Y-shaped metallic stent with the use of Y metallic stent delivery system in the management of airway stenoses involving the lower trachea and the tracheal carina was a simple and safe procedure and with a good short-term clinical efficacy. (authors)

  16. Use of the covered Y-shaped metallic stent in the treatment of airway stenoses involving the lower trachea and the tracheal carina: preliminary clinical study

    Energy Technology Data Exchange (ETDEWEB)

    Ruimin, Yang; Fenbao, Li; Mingqiu, Zhang [Department of Intervention, First Affiliated Hospital, Xinxiang Medical Univ., Xinxiang (China); Gang, Wu; Xinwei, Han

    2007-09-15

    Objective: To describe a new kind of Y-shaped metallic stent delivery system and evaluate its feasibility and preliminary effect for managing multiple airway stenoses involving the lower trachea and the tracheal carina. Methods: The Y-shaped metallic stent delivery system consisted of three-tier structure. The inner-tier was composed of four parallel guiding tubes, which was used for two guidewires and two threads passing through, the middle-tier was delivery catheter, which contained the four guiding tubes, and the outer-tier was introducer sheath. Under the fluoroscopic guidance, 15 patients with multiple stenoses involving the lower trachea and the tracheal carina were treated with the new covered self-expandable Y-shaped metallic stents. Results: Stent placement in the tracheo-bronchial tree was technically successful in all patients with obliteration of the dyspnea immediately after stent placement, and SaO2 was increased form preoperative 75%-89% to postoperative 96%-99%. During follow-up a period of 3-58 weeks (M 22 weeks), all stenosis were resolved without stent-related complications, and the general physical of all 15 patents was improved with no occurrence of obviously dyspnea and bleeding. Karnofsky performance status (KPS) was improved from preoperative 26%-45% to postoperative 72%-95%. Five patients died of the following causes unrelated to stent insertion: multiple organ failure (n=3), cachexia (n=1) and pulmonary infection caused by gastrobronehial fistula (n=1), and the remaining 10 patients were alive with no evidence of dyspnea at the time of this report. Conclusion: Deployment of the covered Y-shaped metallic stent with the use of Y metallic stent delivery system in the management of airway stenoses involving the lower trachea and the tracheal carina was a simple and safe procedure and with a good short-term clinical efficacy. (authors)

  17. Successful endovascular treatment of a hemodialysis graft pseudoaneurysm by covered stent and direct percutaneous thrombin injection.

    LENUS (Irish Health Repository)

    Keeling, Aoife N

    2011-07-25

    Vascular access for hemodialysis remains a challenge for nephrologists, vascular surgeons, and interventional radiologists alike. Arteriovenous fistula and synthetic grafts remain the access of choice for long-term hemodialysis; however, they are subject to complications from infection and repeated needle cannulation. Pseudoaneurysms are an increasingly recognized adverse event. At present, there are many minimally invasive methods to repair these wall defects. We present a graft pseudoaneurysm, which required a combination of endovascular stent graft placement and percutaneous thrombin injection for successful occlusion.

  18. Assessment of safety and efficacy of an indigenous self-expandable fully covered esophageal metal stent for palliation of esophageal cancer.

    Science.gov (United States)

    Padhan, R K; Nongthombam, S K; Venuthurimilli, A; Dhingra, R; Sahni, P; Garg, P K

    2016-01-01

    Patients with unresectable esophageal cancer require palliation for dysphagia. Placement of a self-expandable metal stent (SEMS) is the procedure of choice for palliation of dysphagia. To evaluate the safety and efficacy of an indigenous fully-covered SEMS in patients with esophageal cancer. Eligible patients with unresectable esophageal cancer requiring palliation for dysphagia were included in the study. An indigenous fully covered SEMS of appropriate length was placed under endoscopic and fluoroscopic guidance. Outcome measures assessed were adverse events and improvement in dysphagia. Twenty one patients (mean age 57.71±13.14 years; 17 males) were included. After stenting, dysphagia score decreased from 3.2+0.4 to 0.35+0.74 at 4 weeks. Adverse events included retrosternal pain, respiratory distress and aspiration pneumonia in 12, 2 and 1 patients respectively. Five patients required repeat stenting due to stent migration in 4 (following radiotherapy in 3) and tumour ingrowth in 1. There was primary stent malfunction in one patient. The median survival of patients was 140 (76-199) days, which was higher in those who received radiotherapy. The stent was reasonably safe and effective to relieve dysphagia due to unresectable esophageal cancer.

  19. Intrasellar Iatrogenic Carotid Pseudoaneurysm: Endovascular Treatment with a Polytetrafluoroethylene-Covered S tent

    International Nuclear Information System (INIS)

    Vanninen, R. L.; Manninen, H. I.; Rinne, J.

    2003-01-01

    This case illustrates successful treatment of a large postoperative intrasellar pseudoaneurysm with a polytetrafluoroethylene (PTFE)-covered stent. The advantages and potential disadvantages of this novel method of treatment are discussed. A previously healthy 59-year-old man underwent transsphenoidal operative treatment for hypophyseal macroadenoma,complicated by bleeding. On the 17 th postoperative day the patient had profuse arterial bleeding from his nose requiring posterior tamponade. Subsequent angiography of the left internal carotid artery(ICA) revealed a large pseudoaneurysm located intrasellarly, with the orifice in the anteromedial wall in the ophthalmic segment of the ICA.Surgical treatment of the pseudoaneurysm was considered very risky. A12-mm PTFE-covered stent (JoMed, Ulestraten, Netherlands), manually compressed on a PTCA-balloon (Maxxum 4.5/13 mm, Boston Scientific,Ireland) was endovascularly delivered covering the orifice of the pseudoaneurysm. Control angiography immediately after the intervention and one year later revealed no flow into the pseudoaneurysm and the ICA was fully patent. In conclusion, deployment of a PTFE-covered stent proved to be feasible and successful in the treatment of an intrasellariatrogenic ICA pseudoaneurysm. Adequate anticoagulative treatment after the procedure is essential to prevent thrombotic complications

  20. Management of pancreatic collections with a novel endoscopically placed fully covered self-expandable metal stent: a national experience (with videos).

    Science.gov (United States)

    Chandran, Sujievvan; Efthymiou, Marios; Kaffes, Arthur; Chen, John Wei; Kwan, Vu; Murray, Michael; Williams, David; Nguyen, Nam Quoc; Tam, William; Welch, Christine; Chong, Andre; Gupta, Saurabh; Devereaux, Ben; Tagkalidis, Peter; Parker, Frank; Vaughan, Rhys

    2015-01-01

    Recent medical literature on novel lumen-apposing stents for the treatment of pancreatic fluid collections (PFCs) is limited by small numbers, solo operators, and single-center experience. To evaluate a recently developed lumen-apposing, fully covered self-expandable metal stent (FCSEMS) in the management of PFCs. Retrospective case series. Thirteen tertiary and private health care centers across Australia. Forty-seven patients (median age 51 years) who underwent endoscopic management of PFCs. Insertion of FCSEMS after PFC puncture under EUS guidance. A subgroup of 9 patients underwent direct endoscopic necrosectomy. Technical and clinical success rate, adverse event rate. The technical success rate was 53 of 54 patients (98.1%), and the initial clinical success rate was 36 of 47 (76.6%), which was sustained for more than 6 months in 34 of 36 (94.4%). Early adverse events included 4 cases (7.4%) of stent migration during direct endoscopic necrosectomy, 4 cases (7.4%) of sepsis, 1 case (1.9%) of bleeding, and 1 case (1.9%) of stent migration into the fistula tract. Late adverse events were 6 (11.1%) spontaneous stent migrations, 3 (5.6%) recurrent stent occlusions, 3 (5.6%) tissue ingrowth/overgrowth, and 2 (3.7%) bleeding into PFC. The majority of stents inserted (48 of 54, 88.9%) and removed (31 of 35, 88.6%) in our study were described by the operator as superior to pigtail stents with regard to ease of use. Retrospective study. Although FCSEMSs are technically easier to insert and remove compared with traditional pigtail stents, there are significant limitations to the widespread use of FCSEMSs in the management of PFCs. These include cost, adverse events, and lower-than-expected resolution rates. Copyright © 2015 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

  1. A case of rectovagino-vesical fistula due to radiation therapy for uterine cancer treated with covered expandable metallic stent

    Energy Technology Data Exchange (ETDEWEB)

    Ohtsukasa, Shunroh; Okabe, Satoshi; Tanami, Hideaki [Tokyo Medical and Dental Univ. (Japan). School of Medicine] (and others)

    2002-04-01

    A 65-year-old woman had received a panhysterectomy and radiation therapy for a uterine cancer in 1974 and underwent a drainage operation for a peritonitis due to rupture of the bladder associated with radiation cystitis in 1983. A rectovesical fistula was revealed and partial resection of the bladder and rectum was performed in 1996. In 1998, rectovesical fistula recurred and symptom of fecaluria and contact-type dermatitis at perineal region subsequently worsened. In February, 2000, colonoscopy and gastrograffin-enema revealed a giant recto-vagino-vesical fistula. Although we recommended ileostomy, the patient refused our offer. She gave informed consent to our proposal about the insertion of a covered expandable metallic stent (EMS) into the rectum to treat for fecaluria. After insertion of a covered EMS, fecaluria and contact-type dermatitis at perineal region subsequently improved. Three months later, fecaluria appeared again. Finally, seven months later, severe inflammation occurred at perineal and pubic region because of migration of the covered EMS into the bladder, then we removed the covered EMS and performed ileostomy. It is difficult to use the covered EMS treatment for benign rectovesical or rectovaginal fistula for a long term. (author)

  2. 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

  3. The cover stent custody case that acknowledged QOL improvement on traffic between trachea and esophagus of esophagus cancer

    International Nuclear Information System (INIS)

    Nagase, Hirotsugu; Okada, Kazuyuki; Murata, Kohei

    2011-01-01

    The case was a 60-year-old man. The patient with a main complaint of husky voice was introduced by a nearby doctor to our otolaryngology department at the end of August 2009. Because of the wall thickening image of the upper part (Ut domain) esophagus, left infraclavicular lymph node and mediastium lymphadenopathy syndrome observed by head and neck CT, the patient was transferred to surgery department. Squamous cell carcinoma was diagnosed based on the upper part gastrointestinal tract endoscopy showing a type-3 advanced cancer of the upper thoracic esophagus sized 25-30 cm from nostril. The patient was in progressive disease (PD), fever and coughing, though we performed 2 FAP therapies. A chest CT revealed that there was a passage between the trachea and esophagus. Then, radiation therapy (a total of 60 Gy, 2 Gy at a time) was enforced. After the radio therapy, a covered type Ultraflex esophagus stent was inserted due to a fistula, though the tumor was reduced to 6 mm in size. The patient was passed away five months after the stent custody; a solid food intake was possible until just before he died. (author)

  4. 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.

  5. Are TIPS Stent-Grafts a Contraindication for Future Liver Transplantation?

    International Nuclear Information System (INIS)

    Maleux, Geert; Pirenne, Jacques; Vaninbroukx, Johan; Aerts, Raymond; Nevens, Frederik

    2004-01-01

    Our purpose was to assess the feasibility of orthotopic liver transplantation (OLT) in patients priorly having undergone transjugular intrahepatic portosystemic shunt (TIPS) with an expanded tetrafluoroethylene (e-PTFE)-covered endoprosthesis. In 48 patients an e- PTFE-covered endoprosthesis was inserted to treat severe complications of portal hypertension. In 36 patients the endoprosthesis was inserted during TIPS creation (de novo TIPS); in the other 12 patients the endoprosthesis was placed to repermeabilize the previously created, but occluded bare stent (revision TIPS). Eight of them (5 de novo and 3 revision cases) later underwent an OLT. The hospital records of these patients were reviewed from initial admission, through TIPS, the pre-OLT period, and OLT to current postoperative status. Five de novo and 3 revision cases underwent OLT 4-279 days (mean delay: 80.8 days) after TIPS procedure. All OLT's were performed under veno-venous bypass surgery. De visu surgical inspection confirmed correct positioning of the fully patent stent graft, starting in the portal vein and ending at the junction of the hepatic vein to the inferior caval vein. No surgical difficulty was observed during proximal or distal clamping or during resection of the diseased liver. Correctly positioned e-PTFE-covered nitinol endoprostheses do not interfere with a later OLT and may not be considered as a contraindication in patients who need a TIPS as a bridge to OLT

  6. Removable fully covered self-expandable metal stents in the treatment of common bile duct strictures due to chronic pancreatitis: a case series

    NARCIS (Netherlands)

    Cahen, D. L.; Rauws, E. A.; Gouma, D. J.; Fockens, P.; Bruno, M. J.

    2008-01-01

    The aim of this study was to test the removability of fully covered self-expandable metal stents (FCSEMS) in patients with a benign common bile duct (CBD) stricture. A FCSEMS was inserted in six patients with a CBD stricture due to chronic pancreatitis who were considered to be unfit for surgery,

  7. Self-expandable metalic endotracheal stent

    International Nuclear Information System (INIS)

    Do, Young Soo; Cho, Dae Soon; Cho, Kyung Ja; Lee, Young Soo; Lee, Mi Jae

    1993-01-01

    Six bare stents and six covered stents were inserted in the trachea of 12 dogs under general anesthesia. After 1-10 weeks of observation, the dogs were killed, and the trachea and lung were examined grossly and histologically. Pneumonia and stent migration were observed more frequently at covered stent group. Inflammatory change of the trachea was more severe at covered stent group. In conclusion, we believe that it is inadequate to insert silicone covered stent in the tracheobronchial tree. (Author)

  8. Self-expandable metalic endotracheal stent

    Energy Technology Data Exchange (ETDEWEB)

    Do, Young Soo; Cho, Dae Soon; Cho, Kyung Ja; Lee, Young Soo; Lee, Mi Jae [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

    1993-01-01

    Six bare stents and six covered stents were inserted in the trachea of 12 dogs under general anesthesia. After 1-10 weeks of observation, the dogs were killed, and the trachea and lung were examined grossly and histologically. Pneumonia and stent migration were observed more frequently at covered stent group. Inflammatory change of the trachea was more severe at covered stent group. In conclusion, we believe that it is inadequate to insert silicone covered stent in the tracheobronchial tree. (Author).

  9. Fenestration of a Papyrus PK covered stent to recover the occluded left main bifurcation after sealing a left main perforation during a CTO procedure.

    Science.gov (United States)

    Werner, Gerald S; Ahmed, Waqar H

    2017-09-01

    Covered stents are indicated for coronary perforations, but they may seal off major side branches in that process. We report the successful sealing of an ostial left main perforation, induced by a guide catheter in the course of a retrograde approach to treat a chronic total occlusion (CTO) of the right coronary artery (RCA) in a 76year old woman with prior CABG. The implanted Papyrus covered stent, however, overlapped the left main bifurcation and occluded the non-grafted circumflex artery (CX) resulting in acute ischemia. Through a double lumen catheter advanced over the wire located in the left anterior descending coronary artery (LAD) territory, a stiff recanalization wire could be advanced from the side-port to penetrate the stent membrane towards the CX. This was successfully achieved, and after subsequent dilatation, a drug-eluting stent was implanted in Culotte-fashion from the CX to the left main with subsequent kissing-balloon dilatation. The clinical symptoms subsided immediately, and the RCA was finally recanalized in antegrade parallel wire technique. No periprocedural infarct was observed during 48h of follow-up before discharge. At clinical follow-up of 6months the patient is symptom-free. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. A new fully covered metal stent with anti-migration features for the treatment of malignant dysphagia

    NARCIS (Netherlands)

    Walter, Daisy; van den Berg, Maarten W.; van Hooft, Jeanin E.; Boot, Henk; Scheffer, Robert C. H.; Vleggaar, Frank P.; Siersema, Peter D.

    2014-01-01

    A new esophageal stent with two anti-migration features was developed to minimize migration. The aim of this study was to evaluate the clinical efficacy and safety of this stent in patients with malignant dysphagia. A total of 40 patients with dysphagia due to a malignant obstruction of the

  11. A new fully covered metal stent with anti-migration features for the treatment of malignant dysphagia.

    Science.gov (United States)

    Walter, Daisy; van den Berg, Maarten W; van Hooft, Jeanin E; Boot, Henk; Scheffer, Robert C H; Vleggaar, Frank P; Siersema, Peter D

    2014-12-01

    A new esophageal stent with two anti-migration features was developed to minimize migration. The aim of this study was to evaluate the clinical efficacy and safety of this stent in patients with malignant dysphagia. A total of 40 patients with dysphagia due to a malignant obstruction of the esophagus were prospectively enrolled in this cohort study. Stent placement was technically successful in 39 patients (98 %). The median dysphagia-free time after stent placement was 220 days (95 % confidence interval 94 - 345 days). Nine patients (23 %) experienced recurrent dysphagia due to tissue overgrowth (n = 2), stent fracture (n = 1), and partial (n = 5) or complete (n = 1) stent migration. A total of 16 serious adverse events occurred in 14 patients (36 %), with hemorrhage (n = 3) and severe nausea or vomiting (n = 3) being the most common causes. This new stent design was effective for the palliation of malignant dysphagia and had a low rate of recurrent dysphagia. However, despite the anti-migration features, stent migration was still a major cause of recurrent dysphagia. Furthermore, treatment was associated with a high adverse event rate. Dutch Trial Registration (NTR 3313). © Georg Thieme Verlag KG Stuttgart · New York.

  12. Esophageal leiomyoma in a dog causing esophageal distension and treated by transcardial placement of a self-expanding, covered, nitinol esophageal stent.

    Science.gov (United States)

    Robin, Elisabeth M; Pey, Pascaline B; de Fornel-Thibaud, Pauline; Moissonnier, Pierre H M; Freiche, Valérie

    2018-02-01

    CASE DESCRIPTION A 10-year-old spayed female Rottweiler was referred for evaluation because of a 2-month history of regurgitation and weight loss, despite no apparent change in appetite. The dog had received antiemetic and antacid treatment, without improvement. CLINICAL FINDINGS Physical examination revealed a low body condition score (2/5), but other findings were unremarkable. Diffuse, global esophageal dilatation was noted on plain thoracic radiographs, and normal motility was confirmed through videofluoroscopic evaluation of swallowing. Transhepatic ultrasonographic and CT examination revealed a circumferential, intraparietal lesion in the distal portion of the esophagus causing distal esophageal or cardial subobstruction and no metastases. Incisional biopsy of the lesion was performed, and findings of histologic examination supported a diagnosis of esophageal leiomyoma. TREATMENT AND OUTCOME In view of numerous possible complications associated with esophageal surgery, the decision was made to palliatively treat the dog by transcardial placement of a self-expanding, covered, nitinol esophageal stent under endoscopic guidance. Two weeks after stent placement, radiography revealed complete migration of the stent into the gastric lumen. Gastrotomy was performed, and the stent was replaced and fixed in place. Twenty-four months after initial stent placement, the dog had a healthy body condition and remained free of previous clinical signs. CLINICAL RELEVANCE Diffuse benign muscular neoplasia should be considered as a differential diagnosis for acquired esophageal dilatation in adult and elderly dogs. In the dog of this report, transcardial stent placement resulted in resolution of the clinical signs, with no apparent adverse effect on digestive function. The described procedure could be beneficial for nonsurgical treatment of benign esophageal tumors in dogs.

  13. 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

  14. 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.

  15. 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.

  16. Success and complications of an intra-ductal fully covered self-expanding metal stent (ID-FCSEMS) to treat anastomotic biliary strictures (AS) after orthotopic liver transplantation (OLT).

    Science.gov (United States)

    Aepli, Patrick; St John, Andrew; Gupta, Saurabh; Hourigan, Luke F; Vaughan, Rhys; Efthymiou, Marios; Kaffes, Arthur

    2017-04-01

    Anastomotic biliary strictures (AS) after orthotopic liver transplantation (OLT) belong to the most common biliary complications and cause the biggest morbidity burden after OLT. Metal stents for benign biliary strictures are gaining acceptance with many published series. Traditional metal stent designs seem to have poor durability in AS after OLT. Novel intra-ductal stents are showing promise in these strictures. As a result, we designed a special stent with an antimigration waist and a short stent length with a long removal string that rests in the duodenum for easy removal. This is a retrospective multi-centre Australian study of AS after OLT treated with a novel intra-ductal fully covered self-expanding metal stent. From August 2008 to October 2014, records from three liver transplant centres were reviewed. Totally 36 ID-FCSEMS were inserted in 31 cases to treat an AS after OLT. The mean age of the patients was 56 years, and 61 % were male. The mean time of AS presentation after OLT was 20.3 months. Eight out of our 31 patients were previously treated using multiple plastic stenting over time without any success. Treatment with the ID-FCSEMS was performed with an average treatment time of 3.8 months. Stricture resolution was achieved in 100 %. All attempted stents removals were successful without any difficulty. Complications were reported in 6.5 %. It was pleasing that only one case of stent migration (2.8 %) was seen. Follow-up showed seven cases of AS recurrence (24.1 %), and all were treated successfully with repeat ERCP and stenting (some metal, some plastic). This novel ID-FCSEMS has a high clinical success and low complication rate, and in particular, there was only one case of stent migration. As a result, this stent type is preferred to traditional metal stents for treating AS after OLT.

  17. 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.

  18. 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

  19. Comparison on the Efficacy between Partially Covered Self-Expandable Metal Stent with Funnel-Shaped Enlarged Head versus Uncovered Self-Expandable Metal Stent for Palliation of Gastric Outlet Obstruction

    Directory of Open Access Journals (Sweden)

    Jung Wan Choe

    2018-01-01

    Full Text Available Background. Shape modification has been one of the methods adopted to improve stent patency but has not always translated into positive outcome. The aim of this study was to compare the efficacy of shape-modified partially covered self-expandable metal stent (SEMS that has enlarged head versus uncovered SEMS for palliation of gastric outlet obstruction (GOO. Methods. A total of 48 patients underwent insertion of either enlarged-head SEMS (n=24 or uncovered SEMS (uSEMS (n=24 for palliation of GOO from July 2009 to July 2016. Patients with inoperable or advanced malignancy were included. Technical feasibility and clinical outcomes were compared. Results. Technical success rate was 100% (24/24 and 95.8% (23/24 for enlarged-head SEMS group and uSEMS group, respectively. Clinical success rate was 87.5% (21/24 and 87.0% (20/23 for enlarged-head SEMS group and uSEMS group, respectively. The gastric outlet obstruction scoring system score significantly improved in both groups (p<0.001 for both. Mean survival was similar between the groups: enlarged-head SEMS group, 99.3 days (range, 19–358 days versus uSEMS group, 82.1 days (range, 11–231 days (p=0.418. The mean stent patency also showed no difference between the groups: enlarged-head SEMS group, 87.1 days (range, 8–358 days versus uSEMS group, 60.4 days (range, 2–231 days (p=0.204. With enlarged-head SEMS, distal migration did not occur, but proximal migration was observed in four cases. Conclusions. Distal migration was prevented by shaping the SEMS to have an enlarged head, but improvement in stent patency could not be observed.

  20. USE OF COVERED SELF-EXPANDABLE NITINOL STENT FOR ANASTOMOTIC BILIARY STRUCTURE MANAGEMENT AFTER LIVER TRANSPLANTATION: THE FIRST EXPERIENCE

    Directory of Open Access Journals (Sweden)

    M. N. Kornilov

    2013-01-01

    Full Text Available Aim. The aim of this study focuses on the first experience with self-expandable stents, analysis of its efficacy and safety in the treatment of anastomotic strictures after liver transplantation. Materials and methods. There’re 136 liver transplantations performed from 2004 till 2012. To correct anastomotic strictures we’ve used only the self-expandable coated nitinol stent. We performed stenting in 7 recipient. Result. In 131 liver transplant recipients incidence of biliary strictures has been 5.3%. All of 5 patients have been managed by retrograde or antegrade way. Conclusion. Our first experience demonstrate efficacy and safety of the used tecniques up to 24 months. The analysis of more long-term results is required. 

  1. Mesh-covered (Roadsaver stent as a new treatment modality for symptomatic or high-risk carotid stenosis

    Directory of Open Access Journals (Sweden)

    Roman Machnik

    2017-05-01

    Full Text Available Introduction : Prevention of periprocedural stroke has a crucial role in carotid artery stenting (CAS procedures. Aim : To assess retrospectively 30-day safety and effectiveness of 41 procedures of internal and common carotid artery stenting using the Roadsaver double nitinol layer micromesh stent in 40 non-consecutive patients with symptomatic or high-risk carotid artery stenosis. Material and methods : The patients were men (n = 31 and women (n = 9; mean age was 67.8 ±7.9 years. Femoral access was used in 39 cases, whereas radial access was used in 2. Proximal (n = 27 or distal (n = 14 embolic neuroprotection was used. Results : The Roadsaver stents (nominal diameter 7, 8 or 9 mm, length 25 or 30 mm were implanted successfully in all cases. One minor stroke occurred after common carotid artery intubation with a guiding catheter (before stent deployment and one transient postprocedural ischemic attack (TIA of the ipsilateral cerebral hemisphere was observed. Internal/common carotid artery stenosis severity was evaluated by duplex Doppler. Maximal peak systolic velocity (PSV before CAS was in the range: 2.0–7.0 m/s, mean: 3.9 ±1.0 m/s, at 24–48 h after stenting mean PSV was 1.1 ±0.4 m/s (p < 0.05, and at 30 days 1.1 ±0.3 m/s (p < 0.05. Maximal end-diastolic velocity (EDV was 0.85–3.5 m/s, mean 1.4 ±0.5 m/s, at 24–48 h after stenting mean EDV was 0.3 ±0.1 m/s (p < 0.05, and at 30 days 0.4 ±0.1 m/s (p < 0.05. No restenosis or thrombosis was observed. Angiographic stenosis decreased from 82.9 ±9.1% (range: 61–97% to 19.3 ±7.3% (range: 0–34% (p < 0.05. Conclusions : The CAS using the Roadsaver stent seems to be safe and effective. Further studies involving larger patient populations and longer follow-up are needed.

  2. Comparison of transjugular intrahepatic portosystemic shunt with covered stent and ballon-occluded retrograde transvenous obliteration in managing isolated gastric varices

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung Kwon; Lee, Kristen A.; Sauk, Steven; Korenblat, Kevin [Washington University St. Louis School of Medicine, St. Louis (United States)

    2017-04-15

    Although a transjugular intrahepatic portosystemic shunt (TIPS) is commonly placed to manage isolated gastric varices, balloon-occluded retrograde transvenous obliteration (BRTO) has also been used. We compare the long-term outcomes from these procedures based on our institutional experience. We conducted a retrospective review of patients with isolated gastric varices who underwent either TIPS with a covered stent or BRTO between January 2000 and July 2013. We identified 52 consecutive patients, 27 who had received TIPS with a covered stent and 25 who had received BRTO. We compared procedural complications, re-bleeding rates, and clinical outcomes between the two groups. There were no significant differences in procedural complications between patients who underwent TIPS (7%) and those who underwent BRTO (12%) (p = 0.57). There were also no statistically significant differences in re-bleeding rates from gastric varices between the two groups (TIPS, 7% [2/27]; BRTO, 8% [2/25]; p = 0.94) or in developing new ascites following either procedure (TIPS, 4%; BRTO, 4%; p = 0.96); significantly more patients who underwent TIPS developed hepatic encephalopathy (22%) than did those who underwent BRTO (0%, p = 0.01). There was no statistically significant difference in mean survival between the two groups (TIPS, 30 months; BRTO, 24 months; p = 0.16); median survival for the patients who received TIPS was 16.6 months, and for those who underwent BRTO, it was 26.6 months. BRTO is an effective method of treating isolated gastric varices with similar outcomes and complication rates to those of TIPS with a covered stent but with a lower rate of hepatic encephalopathy.

  3. Microfabrication of crosslinked PTFE by synchrotron radiation

    International Nuclear Information System (INIS)

    Sato, Yasunori; Yamaguchi, Daichi; Oshima, Akihiro; Washio, Masakazu; Katoh, Takanori; Aoki, Yasushi; Ikeda, Shigetoshi; Tanaka, Shigeru

    2003-01-01

    Microfabrication of crosslinked polytetrafluoroethylene (PTFE) using synchrotron radiation (SR) has been demonstrated for production of micro-components applicable to radiation fields. The method of microfabrication was readily capable of obtaining a microstructure with aspect-ratio of 25 made of crosslinked PTFE. The etching rate of crosslinked PTFE was higher than that of non-crosslinked PTFE. The results show that the etching rate of crosslinked PTFE depends only on the degree of crosslinking. The effect of molecular motion on etching process was discussed from temperature dependence on etching rate. Moreover, in order to examine whether any change of chemical structures and crystallinity would be induced by SR-irradiation on PTFE, SR-irradiated PTFE was measured by NMR spectroscopy and DSC analysis. The results showed that the crosslinking reaction of PTFE would be induced by SR-irradiation in the solid state. (author)

  4. 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

  5. Future developments in biliary stenting

    Science.gov (United States)

    Hair, Clark D; Sejpal, Divyesh V

    2013-01-01

    Biliary stenting has evolved dramatically over the past 30 years. Advancements in stent design have led to prolonged patency and improved efficacy. However, biliary stenting is still affected by occlusion, migration, anatomical difficulties, and the need for repeat procedures. Multiple novel plastic biliary stent designs have recently been introduced with the primary goals of reduced migration and improved ease of placement. Self-expandable bioabsorbable stents are currently being investigated in animal models. Although not US Food and Drug Administration approved for benign disease, fully covered self-expandable metal stents are increasingly being used in a variety of benign biliary conditions. In malignant disease, developments are being made to improve ease of placement and stent patency for both hilar and distal biliary strictures. The purpose of this review is to describe recent developments and future directions of biliary stenting. PMID:23837001

  6. Placement of a covered self-expandable nitinol stent for bile duct stricture that caused by ischemic injury after transcatheter arterial chemoembolization in a patient with hepatocellular carcinoma: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Kweon; Seo, Tae Seok; Cha, In Ho; Huh, Sik; Byun, Kwan Soo [Guro Hospital, Korea University College of Medicine, Seoul (Korea, Republic of)

    2008-10-15

    The authors report here on a case of focal stricture in the common hepatic duct that was caused by ischemic bile duct injury after repeat TACE procedures for hepatocellular carcinoma, and the patient was successfully treated with a covered self-expandable nitinol stent.

  7. Heparin-bonded covered stents versus bare-metal stents for complex femoropopliteal artery lesions: the randomized VIASTAR trial (Viabahn endoprosthesis with PROPATEN bioactive surface [VIA] versus bare nitinol stent in the treatment of long lesions in superficial femoral artery occlusive disease).

    Science.gov (United States)

    Lammer, Johannes; Zeller, Thomas; Hausegger, Klaus A; Schaefer, Philipp J; Gschwendtner, Manfred; Mueller-Huelsbeck, Stefan; Rand, Thomas; Funovics, Martin; Wolf, Florian; Rastan, Aljoscha; Gschwandtner, Michael; Puchner, Stefan; Ristl, Robin; Schoder, Maria

    2013-10-08

    The hypothesis that endovascular treatment with covered stents has equal risks but higher efficacy than bare-metal stents (BMS) in long femoropopliteal artery disease was tested. Although endovascular treatment of short superficial femoral artery lesions revealed excellent results, efficacy in long lesions remains unsatisfactory. In a prospective, randomized, single-blind, multicenter study, 141 patients with symptomatic peripheral arterial disease were assigned to treatment with heparin-bonded, covered stents (Viabahn 72 patients) or BMS (69 patients). Clinical outcomes and patency rates were assessed at 1, 6, and 12 months. Mean ± SD lesion length was 19.0 ± 6.3 cm in the Viabahn group and 17.3 ± 6.6 cm in the BMS group. Major complications within 30 days were observed in 1.4%. The 12-month primary patency rates in the Viabahn and BMS groups were: intention-to-treat (ITT) 70.9% (95% confidence interval [CI]: 0.58 to 0.80) and 55.1% (95% CI: 0.41 to 0.67) (log-rank test p = 0.11); treatment per-protocol (TPP) 78.1% (95% CI: 0.65 to 0.86) and 53.5% (95% CI: 0.39 to 0.65) (hazard ratio: 2.23 [95% CI: 1.14 to 4.34) (log-rank test p = 0.009). In lesions ≥20 cm, (TransAtlantic Inter-Society Consensus class D), the 12-month patency rate was significantly longer in VIA patients in the ITT analysis (VIA 71.3% vs. BMS 36.8%; p = 0.01) and the TPP analysis (VIA 73.3% vs. BMS 33.3%; p = 0.004). Freedom from target lesion revascularization was 84.6% for Viabahn (95% CI: 0.72 to 0.91) versus 77.0% for BMS (95% CI: 0.63 to 0.85; p = 0.37). The ankle-brachial index in the Viabahn group significantly increased to 0.94 ± 0.23 compared with the BMS group (0.85 ± 0.23; p stents compared with BMS in lesions ≥20 cm and for all lesions in the TPP analysis. In the ITT analysis for all lesions, which was flawed by major protocol deviations in 8.5% of the patients, the difference was not significant. (GORE VIABAHN® endoprosthesis with bioactive propaten surface versus bare

  8. Chemiluminescence emission from irradiated polytetrafluoroethylene (PTFE)

    International Nuclear Information System (INIS)

    Zhong Xiaoguang; Sun Jiazhen; Yoshii, Fumio; Sasaki, Takashi; Makuuchi, Keizo

    2000-01-01

    PTFE is well known for its chemical and high temperature resistance and also for its high-energy radiation sensitivity. The present work deals with the radiation-induced emission of chemiluminescence from PTFE film, which is generally thought as a measure of radiation induced oxidation reaction in irradiated polymer. The observation that the much stronger chemiluminescence emission from PTFE than that from other polymeric system indicate the unusual high degree of radiation induced oxidation in PTFE. On the other hand the temperature and atmosphere effect during radiation on emission of chemiluminescence were also reported. (author)

  9. Endotracheal expandable metallic stent placement in dogs

    Energy Technology Data Exchange (ETDEWEB)

    Sawada, S; Tanabe, Y; Fujiwara, Y; Koyama, T; Tanigawa, N; Kobayashi, M; Katsube, Y; Nakamura, H [Tottori Univ. School of Medicine, Yonago (Japan). Dept. of Radiology Research Inst. for Microbial Diseases, Osaka (Japan). Dept. of Radiology

    1991-01-01

    Various types of Gianturco zig-zag wire stent were implanted into the tracheas of 4 dogs to define the suitable characteristics of the endotracheal wire stent in these animals. These stents were constructed of 0.45, and 0.33 mm stainless steel wire. The diameter of the fully expanded stents was 3 cm and their lengths were 2, 3, and 4 cm. The 2 cm stent constructed of 0.33 mm wire showed minimum pathologic changes of the trachea of the dog compared to the other stents, and at the same time had a complete covering of ciliated columnar epithelium over the stent surface. (orig.).

  10. Radiation processing for PTFE composite reinforced with carbon fiber

    International Nuclear Information System (INIS)

    Akihiro Oshima; Akira Udagawa; Yousuke Morita

    1999-01-01

    The present work is an attempt to evaluate the performance of crosslinked PTFE as a polymer matrix for carbon fiber-reinforced composite materials. The carbon fiber-reinforced PTFE pre-composite, which is laminated with PTFE fine powder, is crosslinked by electron beam irradiation. Mechanical and frictional properties of the crosslinked PTFE composite obtained are higher than those of PTFE resin. The crosslinked PTFE composite with high mechanical and radiation resistant performance is obtained by radiation crosslinking process

  11. Randomized clinical comparison of the dual-therapy CD34 antibody-covered sirolimus-eluting Combo stent with the sirolimus-eluting Orsiro stent in patients treated with percutaneous coronary intervention

    DEFF Research Database (Denmark)

    Jakobsen, Lars; Christiansen, Evald H; Maeng, Michael

    2018-01-01

    Background: The Combo stent (OrbusNeich, Hoevelaken, the Netherlands) combining an abluminal, bioabsorbable polymer eluting sirolimus with a luminal CD34+ antibody to capture endothelial progenitor cells has been developed to further improve safety and efficacy of coronary interventions. We have...... designed a large-scale registry-based randomized clinical trial to compare the Combo stent to the Orsiro stent (Biotronik, Bülach, Switzerland) in patients undergoing percutaneous coronary intervention. Methods: The SORT OUT X study will randomly assign 3,140 patients to treatment with Combo or Orsiro...... stents at 3 sites in Western Denmark. Patients are eligible if they are ≥18 years old, have chronic stable coronary artery disease or acute coronary syndromes, and have ≥1 coronary lesion with >50% diameter stenosis requiring treatment with a drug-eluting stent. The primary end point target lesion...

  12. Future developments in biliary stenting

    Directory of Open Access Journals (Sweden)

    Hair CD

    2013-06-01

    Full Text Available Clark D Hair,1 Divyesh V Sejpal21Department of Medicine, Section of Gastroenterology and Hepatology, Baylor College of Medicine, Houston, TX, USA; 2Department of Medicine, Section of Gastroenterology, Hofstra North Shore-LIJ School of Medicine, North Shore University Hospital, Manhasset, NY, USAAbstract: Biliary stenting has evolved dramatically over the past 30 years. Advancements in stent design have led to prolonged patency and improved efficacy. However, biliary stenting is still affected by occlusion, migration, anatomical difficulties, and the need for repeat procedures. Multiple novel plastic biliary stent designs have recently been introduced with the primary goals of reduced migration and improved ease of placement. Self-expandable bioabsorbable stents are currently being investigated in animal models. Although not US Food and Drug Administration approved for benign disease, fully covered self-expandable metal stents are increasingly being used in a variety of benign biliary conditions. In malignant disease, developments are being made to improve ease of placement and stent patency for both hilar and distal biliary strictures. The purpose of this review is to describe recent developments and future directions of biliary stenting.Keywords: plastic stents, self-expandable metal stents, drug eluting stents, bioabsorbable stents, malignant biliary strictures, benign biliary strictures

  13. A fine surface roughness electroless Ni–P–PTFE composite modified stamper for light guide plate application

    International Nuclear Information System (INIS)

    Pan, K; Fu, C

    2010-01-01

    Electroless Ni–P–PTFE composite coating technology takes advantage of the beneficial properties from both Ni–P alloy and PTFE, such as good wear resistance, good anti-adhesion, dry lubrication, low coefficient of friction and good corrosion resistance. It has been applied in many mold industries. However, the Ni–P–PTFE composite coating suffers from bad surface roughness, when the PTFE particles incorporate into a Ni–P matrix. This severely hampers the technology to be applied to optical grade applications. In this paper, we propose a trick to generate a fine surface roughness (FSR) electroless Ni–P–PTFE composite to modify a nickel stamper. Using this new method, the nickel stamper can be covered by a Ni–P–PTFE functional layer and can keep the original surface property at the same time, namely the optical properties. We have chosen 4.5 inch (97 mm × 59 mm × 0.6 mm) light guide plates (LGPs) to demonstrate the effectiveness of the procedure. For the sake of comparison, the LGPs were produced by injection molding with three kinds of stampers including an original SUS430 master, an electroless Ni–P–PTFE composite coated nickel stamper and an FSR electroless Ni–P–PTFE composite modified stamper. We measured and discussed the optical performances at both the element level and system level, namely complete back light units.

  14. Control of cell behavior on PTFE surface using ion beam irradiation

    International Nuclear Information System (INIS)

    Kitamura, Akane; Kobayashi, Tomohiro; Meguro, Takashi; Suzuki, Akihiro; Terai, Takayuki

    2009-01-01

    A polytetrafluoroethylene (PTFE) surface is smooth and biologically inert, so that cells cannot attach to it. Ion beam irradiation of the PTFE surface forms micropores and a melted layer, and the surface is finally covered with a large number of small protrusions. Recently, we found that cells could adhere to this irradiated PTFE surface and spread over the surface. Because of their peculiar attachment behavior, these surfaces can be used as biological tools. However, the factors regulating cell adhesion are still unclear, although some new functional groups formed by irradiation seem to contribute to this adhesion. To control cell behavior on PTFE surfaces, we must determine the effects of the outermost irradiated surface on cell adhesion. In this study, we removed the thin melted surface layer by postirradiation annealing and investigated cell behavior on the surface. On the surface irradiated with 3 x 10 16 ions/cm 2 , cells spread only on the remaining parts of the melted layer. From these results, it is clear that the melted layer had a capacity for cell attachment. When the surface covered with protrusions was irradiated with a fluence of 1 x 10 17 ions/cm 2 , the distribution of cells changed after the annealing process from 'sheet shaped' into multicellular aggregates with diameters of around 50 μm. These results indicate that we can control cell behavior on PTFE surfaces covered with protrusions using irradiation and subsequent annealing. Multicellular spheroids can be fabricated for tissue engineering using this surface.

  15. Long-Term Outcomes of Double-Layered Polytetrafluoroethylene Membrane-Covered Self-Expandable Segmental Metallic Stents (Uventa) in Patients with Chronic Ureteral Obstructions: Is It Really Safe?

    Science.gov (United States)

    Kim, Myong; Hong, Bumsik; Park, Hyung Keun

    2016-12-01

    To evaluate the long-term clinical efficacy and safety of double-layered polytetrafluoroethylene membrane-covered self-expandable segmental metallic stents (Uventa) in patients with chronic ureteral obstruction. In a retrospective study, a total of 50 ureter units (44 patients) with chronic obstructions were included from July 2010 to May 2015. Indications for Uventa placement were primary stenting for malignant ureteral obstruction, failed conventional polymeric Double-J stent (PS), or percutaneous nephrostomy (PCN) technique, with comorbidities or fears limiting PS/PCN changes, or with irritation or pain due to PS/PCN. Patients underwent Uventa stent placement using the antegrade or retrograde approach. There were no immediate procedure-related complications, and all stents were placed in the proper sites. During the median follow-up of 30.9 (interquartile range [IQR], 8.1-49.0) months, the primary (no obstruction and no additional intervention) and overall success (no obstruction and no additional intervention except supplementary Uventa) was 30.0% and 34.0%, respectively. Moreover, 14 of 50 ureter units (28.0%) experienced major complications (≥Clavien-Dindo class IIIb), such as ureteroarterial fistula (three cases, 6.0%), ureteroenteric fistula (three, 6.0%), ureterovaginal fistula (one, 2.0%), ureter perforation (one, 2.0%), uncontrollable bleeding (one, 2.0%), and complete obstruction (five, 10.0%). On univariate analysis, major complications were associated with female (odds ratio [OR] = 6.000), cervical cancer (OR = 4.667), ureteral stricture length (≥6.0 cm, OR = 4.583), and placement duration (≥24.0 months, OR = 20.429; all p stent demonstrated poor treatment outcomes with frequent major complications in patients with chronic ureteral obstructions.

  16. Recycling of PTFE by means of ionizing rays

    International Nuclear Information System (INIS)

    Lee, D.W.

    1994-01-01

    By treatment with beta or gamma rays, PTFE waste is converted to high-grade PTFE fine powder. High-molecular weight PTFE is degraded to low-molecular weight PTFE. Due to this the density, the degree of crystallinity, and the melt flow index are increased, which enhances the brittleness of the material. Irradiation of PTFE thus facilitates milling and makes the material pourable and free-flowing. Milled PTFE fine powder, lie PTFE plastic, combines temperature resistance, weather fastness, and chemical stability with good slip behaviour and antiadhesive properties. Areas of application for fine powder include additives for plastics, printing inks, nonstick coatings, and antifriction lacquers. (orig.) [de

  17. Is sonographic surveillance of polytetrafluoroethylene-covered transjugular intrahepatic portosystemic shunts (TIPS) necessary? A single centre experience comparing both types of stents

    Energy Technology Data Exchange (ETDEWEB)

    Pan, J.-J.; Chen, C. [Department of Medicine, Division of Gastroenterology, Hepatology, and Nutrition, Section of Hepatobiliary Disease, University of Florida, Gainesville, FL (United States); Geller, B. [Department of Radiology, University of Florida, Gainesville, FL (United States); Firpi, R.; Machicao, V.I. [Department of Medicine, Division of Gastroenterology, Hepatology, and Nutrition, Section of Hepatobiliary Disease, University of Florida, Gainesville, FL (United States); Caridi, J.G. [Department of Radiology, University of Florida, Gainesville, FL (United States); Nelson, D.R. [Department of Medicine, Division of Gastroenterology, Hepatology, and Nutrition, Section of Hepatobiliary Disease, University of Florida, Gainesville, FL (United States); Morelli, G. [Department of Medicine, Division of Gastroenterology, Hepatology, and Nutrition, Section of Hepatobiliary Disease, University of Florida, Gainesville, FL (United States)], E-mail: morelgj@medicine.ufl.edu

    2008-10-15

    Aim: To investigate whether sonographic (US) surveillance of polytetrafluoroethylene covered transjugular intrahepatic portosystemic shunts (TIPS) is necessary. Materials and methods: We identified 128 patients who underwent TIPS for complications of portal hypertension between January 2001 and December 2005 at a large tertiary centre. Procedural data were retrospectively analysed. US surveillance of the TIPS was performed at baseline with scheduled follow-up or whenever shunt dysfunction was suspected. Clinical and radiology reports were compared to assess US surveillance of the TIPS. Results: Four hundred and twenty-six US studies were performed, with a median of three per patient (range 1-5). The median follow-up period was 378 days (range 1-1749 days). Twenty-three patients (18%) had baseline US studies performed only whereas 105 (82%) also had follow-up studies. Forty-one (32%) of 128 patients [32 (78%) Wallstent, nine (22%) Viatorr] had Doppler ultrasound abnormalities noted. Venography was performed in all 41 patients. Abnormal venography and elevated hepatic venous pressure gradient (HVPG) was seen in 34 (82.9%) of the 41 patients [29 (85.3%) Wallstent, five (14.7%) Viatorr]. Among the 34 patients, 17 (50%) [13 (76.5%) Wallstent, four (23.5%) Viatorr] had venographic abnormalities noted at the hepatic venous end accompanied by increased HVPG. All four of the Viatorr patients had minor narrowing at the hepatic venous end and HVPG measurements that ranged 3-4 mm Hg above 12 mm Hg. Conclusion: Considering the improved patency of covered stents in TIPS, US surveillance may be superfluous after the baseline study.

  18. Outcomes of the Use of Fully Covered Esophageal Self-Expandable Stent in the Management of Colorectal Anastomotic Strictures and Leaks

    Directory of Open Access Journals (Sweden)

    Chad J. Cooper

    2014-01-01

    Full Text Available Introduction. Colorectal anastomotic leak or stricture is a dreaded complication leading to significant morbidity and mortality. The novel use of self-expandable metal stents (SEMS in the management of postoperative colorectal anastomotic leaks or strictures can avoid surgical reintervention. Methods. Retrospective study with particular attention to the indications, operative or postoperative complications, and clinical outcomes of SEMS placement for patients with either a colorectal anastomotic stricture or leak. Results. Eight patients had SEMS (WallFlex stent for the management of postoperative colorectal anastomotic leak or stricture. Five had a colorectal anastomotic stricture and 3 had a colorectal anastomotic leak. Complete resolution of the anastomotic stricture or leak was achieved in all patients. Three had recurrence of the anastomotic stricture on 3-month flexible sigmoidoscopy follow-up after the initial stent was removed. Two of these patients had a stricture that was technically too difficult to place another stent. Stent migration was noted in 2 patients, one at day 3 and the other at day 14 after stent placement that required a larger 23 mm stent to be placed. Conclusions. The use of SEMS in the management of colorectal anastomotic leaks or strictures is feasible and is associated with high technical and clinical success rate.

  19. Carbon protrusions on PTFE surface prepared by ion irradiation and chemical defluorination

    Science.gov (United States)

    Kobayashi, T.; Iwaki, M.

    2006-01-01

    A surface of PTFE was covered with small protrusions by ion-beam irradiation. In this study, we converted PTFE protrusions into carbon protrusions by a defluorination (carbonization) process using sodium vapor. The morphology, composition and structure were analyzed by SEM-EDX, Raman spectroscopy and TEM. The irradiated PTFE sheets were packed in evacuated glass tubes with a sodium block and kept at 473 K for 2-48 h. The samples were then rinsed in HCl and distilled water to remove NaF precipitates. The EDX measurement showed that the NaF precipitates were completely removed by washing, and the percentage of carbon atoms was controlled from 60% to 99% by the treatment. Raman spectra showed that graphite structures grow during the defluorination process. TEM micrographs showed that the protrusions have a bubble structure and are covered with a thin wall. The carbonized protrusions were conductive and grew perpendicular to the substrate.

  20. MRSA-Infected External Iliac Artery Pseudoaneurysm Treated with Endovascular Stenting

    International Nuclear Information System (INIS)

    Clarke, M.G.; Thomas, H.G.; Chester, J.F.

    2005-01-01

    A 48-year-old woman with severe juvenile-onset rheumatoid arthritis presented with a bleeding cutaneous sinus distal to her right total hip replacement scar. Methicillin resistant Staphylococcus aureus (MRSA) was isolated on culture. She had previously undergone bilateral total hip and knee replacements at aged 23 and six years later had the right knee prosthesis removed for infection, with subsequent osteomyelitis of the femoral shaft and right total hip prosthesis disruption. Peripheral arteriography was performed in view of persistent bleeding from the sinus, which revealed a 6 cm false aneurysm filling from and compressing the right external iliac artery (EIA). A PTFE-covered, balloon expandable JOSTENT was deployed in the right EIA, successfully excluding the false aneurysm and preventing further bleeding from the sinus. No graft infection was reported at 12 months. This case illustrates the potential use of endovascular stent-grafting in the treatment of an infected pseudoaneurysm

  1. Endovascular Treatment of a Giant Superior Mesenteric Artery Pseudoaneurysm Using a Nitinol Stent-Graft

    International Nuclear Information System (INIS)

    Gandini, Roberto; Pipitone, Vincenzo; Konda, Daniel; Pendenza, Gianluca; Spinelli, Alessio; Stefanini, Matteo; Simonetti, Giovanni

    2005-01-01

    A 68-year-old woman presenting with gastrointestinal bleeding (hematocrit 19.3%) and in a critical clinical condition (American Society of Anesthesiologists grade 4) from a giant superior mesenteric artery pseudoaneurysm (196.0 x 131.4 mm) underwent emergency endovascular treatment. The arterial tear supplying the pseudoaneurysm was excluded using a 5.0 mm diameter and 31 mm long monorail expanded polytetrafluoroethylene (ePTFE)-covered self-expanding nitinol stent. Within 6 days of the procedure, a gradual increase in hemoglobin levels and a prompt improvement in the clinical condition were observed. Multislice CT angiograms performed immediately, 5 days, 30 days and 3 months after the procedure confirmed the complete exclusion of the pseudoaneurysm

  2. Development of a Diehard GEM using PTFE insulator substrate

    OpenAIRE

    Wakabayashi, M.; Komiya, K.; Tamagawa, T.; Takeuchi, Y.; Aoki, K.; Taketani, A.; Hamagaki, H.

    2014-01-01

    We have developed the gas electron multiplier (GEM) using polytetrafluoroethylene (PTFE) insulator substrate (PTFE-GEM). Carbonization on insulator layer by discharges shorts the GEM electrodes, causing permanent breakdown. Since PTFE is hard to be carbonized against arc discharges, PTFE-GEM is expected to be robust against breakdown. Gains as high as 2.6x10^4 were achieved with PTFE-GEM (50 um thick) in Ar/CO2 = 70%/30% gas mixture at V_GEM = 730V. PTFE-GEM never showed a permanent breakdown...

  3. MRT of carotid stents: influence of stent properties and sequence parameters on visualization of the carotid artery lumen

    International Nuclear Information System (INIS)

    Straube, T.; Wolf, S.; Alfke, K.; Jansen, O.; Flesser, A.; Deli, M.; Nabavi, A.

    2005-01-01

    Purpose: To evaluate MR artifacts of carotid artery stents and to optimize stent properties and sequence parameters. Material and Methods: Four carotid artery stents - Wallstent (mediloy), Precise (nitinol), ACCULINK (nitinol) and a stent prototype (nitinol) - were investigated in a flow model of the cervical vessels. The model was made of silicon tubing and a flow pump that produces realistic flow curves of the carotid artery. To investigate the effects of magnetic susceptibility and radiofrequency induced shielding artifacts, turbo spin echo and gradient echo sequences as well as CE-MRAs were measured. To improve the visualization of the stent lumen in a CE-MRA, flip angle as well as geometry and covering of the stent prototype were altered. Results: Susceptibility artifacts in stents of the carotid artery only influence the lumen visualization at the proximal and distal end of the braided mediloy stent. A change of stent coverings has no significant influence on radiofrequency artifacts, whereas a reduction in linking elements between stent segments and a change in diameter of stent struts improves visualization of the stent lumen. By increasing the flip angle in a CE-MRA, visualization of the stent lumen is possible in both mediloy and nitinol stents. Conclusion: The choice of stent material and changes in stent geometry as well as the optimization of the flip angle of the CE-MRA may reduce susceptibility and radiofrequency artifacts, rendering feasible the CE-MRA of a stented carotid artery. (orig.)

  4. Application of willis covered stent in the treatment of aneurysms located in the cisternal segment of the internal carotid artery: a pilot comparative study with long-term follow-up results

    International Nuclear Information System (INIS)

    Zhu Yueqi; Li Minghua; Fang Chun; Wang Wu; Zhang Peilei; Cheng Yingsheng; Tan Huaqiao; Wang Jianbo

    2010-01-01

    Objective: Complicated aneurysms located in the cisternal segment of the internal carotid artery(ICA-CSA) present unique therapeutic difficulties. This study is to discuss the feasibility of the Willis stent-graft in treating complicated ICA-CSA by comparing its effect with that of coiling therapy. Methods: Willis covered stents were employed in 19 complicated ICA-CSAs (group A), while coils were used in 17 complicated ICA-CSAs (group B). Follow-up angiography was performed to investigate aneurysm recurrence, endoleak and parent artery (PA) stenosis. Kaplan-Meier curves were constructed to compare the recurrence-free and PA stenosis-free rate in both groups. Results: Total exclusion was immediately achieved in 13 ICA-CSAs and minor endoleaks presented in 5 cases in group A. Total or near-total occlusion was achieved in 7 ICA-CSAs, subtotal occlusion in 8 and partial occlusion in 2 cases in group B after coiling. Acute thrombosis occurred in 1 patient in either group and re-hemorrhage happened in 1 patient after coiling. Follow-up angiography in group A revealed that 16 ICA-CSAs were completely isolated, with two parent arteries showing mild in-stent stenosis. Eighteen months after the procedure, Kaplan-Meier analysis showed that the recurrence-free rate was 93.3% and 50%, while the stenosis-free rate of parent artery was 87.5% and 100% in group A and in Group B, respectively. In group A and group Bthe clinical neurological symptoms were fully recovered in 9 and 9, obviously improved in 3 and 5, unchanged in 2 and 2, and aggravated in one and 0 patients, respectively. Conclusion: The implantation of Willis stent-graft is a feasible endovascular therapy for complicated ICA-CSAs. When the parent artery is very tortuous or when the risk that a main collateral branch may be wrongly covered and occluded is present, the implantation of Willis covered stent can not be taken as the treatment of first choice. (authors)

  5. Development of a Diehard GEM using PTFE insulator substrate

    International Nuclear Information System (INIS)

    Wakabayashi, M; Tamagawa, T; Takeuchi, Y; Aoki, K; Taketani, A; Komiya, K; Hamagaki, H

    2014-01-01

    We have developed the gas electron multiplier (GEM) using polytetrafluoroethylene (PTFE) insulator substrate (PTFE-GEM). Carbonization on insulator layer by discharges shorts the GEM electrodes, causing permanent breakdown. Since PTFE is hard to be carbonized against arc discharges, PTFE-GEM is expected to be robust against breakdown. Gains as high as 2.6 × 10 4 were achieved with PTFE-GEM (50 μm thick) in Ar/CO 2 = 70%/30% gas mixture at V GEM = 730 V. PTFE-GEM never showed a permanent breakdown even after suffering more than 40000 times discharges during the experiment. The result demonstrates that PTFE-GEM is really robust against discharges. We conclude that PTFE is an excellent insulator material for the GEM productions

  6. Biomimetic Fluorocarbon Surfactant Polymers Reduce Platelet Adhesion on PTFE/ePTFE Surfaces

    Science.gov (United States)

    Wang, Shuwu; Gupta, Anirban Sen; Sagnella, Sharon; Barendt, Pamela M.; Kottke-Marchant, Kandice; Marchant, Roger E.

    2010-01-01

    We describe a series of fluorocarbon surfactant polymers designed as surface-modifying agents for improving the thrombogenicity of ePTFE vascular graft materials by the reduction of platelet adhesion. The surfactant polymers consist of a poly(vinyl amine) backbone with pendent dextran and perfluoroundecanoyl branches. Surface modification is accomplished by a simple dip-coating process in which surfactant polymers undergo spontaneous surface-induced adsorption and assembly on PTFE/ePTFE surface. The adhesion stability of the surfactant polymer on PTFE was examined under dynamic shear conditions in PBS and human whole blood with a rotating disk system. Fluorocarbon surfactant polymer coatings with three different dextran to perfluorocarbon ratios (1:0.5, 1:1 and 1:2) were compared in the context of platelet adhesion on PTFE/ePTFE surface under dynamic flow conditions. Suppression of platelet adhesion was achieved for all three coated surfaces over the shear-stress range of 0–75 dyn/cm2 in platelet-rich plasma (PRP) or human whole blood. The effectiveness depended on the surfactant polymer composition such that platelet adhesion on coated surfaces decreased significantly with increasing fluorocarbon branch density at 0 dyn/cm2. Our results suggest that fluorocarbon surfactant polymers can effectively suppress platelet adhesion and demonstrate the potential application of the fluorocarbon surfactant polymers as non-thrombogenic coatings for ePTFE vascular grafts. PMID:19323880

  7. Thermal radiation properties of PTFE plasma

    Science.gov (United States)

    Liu, Xiangyang; Wang, Siyu; Zhou, Yang; Wu, Zhiwen; Xie, Kan; Wang, Ningfei

    2017-06-01

    To illuminate the thermal transfer mechanism of devices adopting polytetrafluoroethylene (PTFE) as ablation materials, the thermal radiation properties of PTFE plasma are calculated and discussed based on local thermodynamic equilibrium (LTE) and optical thin assumptions. It is clarified that line radiation is the dominant mechanism of PTFE plasma. The emission coefficient shows an opposite trend for both wavelength regions divided by 550 nm at a temperature above 15 000 K. The emission coefficient increases with increasing temperature and pressure. Furthermore, it has a good log linear relation with pressure. Equivalent emissivity varies complexly with temperature, and has a critical point between 20 000 K to 25 000 K. The equivalent cross points of the average ionic valence and radiation property are about 10 000 K and 15 000 K for fully single ionization.

  8. 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.

  9. Friction coefficients of PTFE bearing liner

    Science.gov (United States)

    Daniels, C. M.

    1979-01-01

    Data discusses frictional characteristics of PTFE (polytetrafluoroethylene) under temperature extremes and in vacuum environment. Tests were also run on reduced scale hardware to determine effects of vacuum. Data is used as reference by designers of aircraft-control system rod-end bearings and for bearings used in polar regions.

  10. Long-term results of PTFE grafts.

    Science.gov (United States)

    Hedin, Ulf

    2015-01-01

    Vascular surgeons are essential in "lifeline" creation for hemodialysis patients and should be the central player in any multidisciplinary access service together with nephrologists, dialysis staff and interventional radiology. In this position, access surgeons are involved in complicated clinical decision making regarding primary and secondary access selection, which throughout the last decade has been largely aided, and influenced, by national and international guidelines as well as other initiatives. These recommendations, unanimously and appropriately, advocate the placement of native fistulas over synthetic grafts (the majority grafts from expanded polytetrafluoroethylene, ePTFE, herein referred to as PTFE) based on the superiority of fistulas with respect to complications such as infections and thrombosis. Nevertheless, the use of PTFE grafts for hemodialysis access is an accepted and firmly established alternative to native fistulas where data today reveal unwanted consequences to overinterpretation of established guidelines such as increased catheter use. This information highlights a need for an adjustment of access selection strategies based on patient-centered algorithms. Here, available results on PTFE graft performance in hemodialysis access is recapitulated, with respect to both conventional grafts and technical modifications, and conclude with a modified approach to primary access selection.

  11. Estudo da resposta tissular à endoprótese recoberta de jugular bovina em veia cava inferior de suínos Bovine jugular covered stent-graft implanted in swine inferior vena cava - a study of tissue response

    Directory of Open Access Journals (Sweden)

    Cristina Ribeiro Riguetti Pinto

    2006-06-01

    Full Text Available OBJETIVO: Avaliar a resposta tissular a uma endoprótese, com cobertura biológica heteróloga, implantada em veia cava inferior de suínos. MÉTODO: Desenvolvemos uma endoprótese auto-expansível, revestida com um segmento de jugular bovina, conservada por processo L-hydro e suturada em um stent de aço inoxidável 316L. O dispositivo introdutor utilizado foi a bainha de liberação da endoprótese aórtica Taheri-Leonhardt (Flórida, EUA. Foram implantadas endopróteses em 10 suínos, todas na veia cava infra-renal. Os animais foram submetidos à flebografia peroperatória. À necropsia, após 2 meses, cada endoprótese foi retirada em bloco e analisada macroscopicamente, visando a avaliação da perviedade, aderência aos tecidos vizinhos e incorporação à parede venosa; e, histopatologicamente, visando a resposta histológica ao enxerto. RESULTADOS: Na análise macroscópica, todas as endopróteses encontravam-se pérvias e totalmente incorporadas à parede venosa, porém seis apresentavam trabeculações grosseiras no seu interior e quatro algum grau de fibrose perivascular. Três animais desenvolveram linfocele, uma retroperitoneal e as outras na parede abdominal. No estudo histopatológico, observamos reação inflamatória granulomatosa tipo corpo estranho em todos os casos, sendo predominante na camada média (80%. CONCLUSÃO: O modelo estudado apresentou baixa trombogenicidade, corroborando com a eficácia do meio de conservação e material escolhidos; porém, baixa biocompatibilidade, provavelmente pelo obstáculo imunológico dos xenoenxertos e resposta tissular exagerada do território venoso.OBJECTIVE: To evaluate tissue response to a bovine jugular vein covered stent when implanted in the swine inferior vena cava. METHOD: We developed a self-expanding stent, using a segment of L-hydro conserved bovine jugular vein, which was trimmed and sutured to a 316L stainless steel stent. We used the Taheri-Leonhardt delivery system for

  12. 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

  13. Edge Stenosis After Covered Stenting for Long Superficial Femoral Artery Occlusive Disease: Risk Factor Analysis and Prevention With Drug-Coated Balloon Angioplasty.

    Science.gov (United States)

    Lin, Ting-Chao; Huang, Chun-Yang; Chen, Po-Lin; Lee, Chiu-Yang; Shih, Chun-Che; Chen, I-Ming

    2018-06-01

    To report a retrospective analysis of risk factors for edge restenosis after Viabahn stent-graft treatment of superficial femoral artery (SFA) occlusive disease and determine any protective effect of drug-coated balloons (DCBs) used at the time of stent-graft implantation. Between October 2011 and July 2016, 110 patients (mean age 73.3±7.6 years; 78 men) were treated with the Viabahn stent-graft for long SFA occlusions. Thirty-eight (34.5%) patients had DCB reinforcement at the distal edge of the stent-graft. For analysis, the population was divided into groups of no edge stenosis patients (n=88; mean lesion length 22.4±4.2 cm) and edge stenosis patients (n=22; mean lesion length 23.5±5.7 cm). The clinical outcomes, ankle-brachial indices, computed tomography angiography findings, and patency were compared at a minimum of 12 months. Logistic regression analysis was employed to determine risk factors for edge stenosis; the results are presented as the odds ratio (OR) and 95% confidence interval. No differences in clinical or procedural characteristics were identified except the higher incidence of diabetes (p=0.008) and greater need for retrograde access (p=0.033) in the edge stenosis group. DCB reinforcement reduced the incidence of edge stenosis (p=0.021) and target lesion revascularization (TLR; p=0.010) and resulted in a significantly higher 1-year primary patency rate (92.1% vs 76.4%, p=0.042). However, multivariate analysis revealed only poor distal runoff (OR 0.31, 95% CI 0.11 to 0.83, p=0.020) as a predictor of edge stenosis. The risk of edge stenosis after Viabahn implantation was higher in patients with poor distal runoff. DCB reinforcement over the distal edge reduced edge stenosis, decreased 1-year TLR, and improved 1-year primary patency.

  14. Self expandable polytetrafluoroethylene stent for carotid blowout syndrome.

    Science.gov (United States)

    Tatar, E C; Yildirim, U M; Dündar, Y; Ozdek, A; Işik, E; Korkmaz, H

    2012-01-01

    Carotid blowout syndrome (CBS) is an emergency complication in patients undergoing treatment for head and neck cancers. The classical management of CBS is the ligation of the common carotid artery, because suturing is not be possible due to infection and necrosis of the field. In this case report, we present a patient with CBS, in whom we applied a self-expandable polytetrafluoroethylene (PTFE) stent and observed no morbidity. Endovascular stent is a life-saving technique with minimum morbidity that preserves blood flow to the brain. We believe that this method is preferable to ligation of the artery in CBS.

  15. 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

  16. Polymeric Biodegradable Stent Insertion in the Esophagus

    Directory of Open Access Journals (Sweden)

    Kai Yang

    2016-04-01

    Full Text Available Esophageal stent insertion has been used as a well-accepted and effective alternative to manage and improve the quality of life for patients diagnosed with esophageal diseases and disorders. Current stents are either permanent or temporary and are fabricated from either metal or plastic. The partially covered self-expanding metal stent (SEMS has a firm anchoring effect and prevent stent migration, however, the hyperplastic tissue reaction cause stent restenosis and make it difficult to remove. A fully covered SEMS and self-expanding plastic stent (SEPS reduced reactive hyperplasia but has a high migration rate. The main advantage that polymeric biodegradable stents (BDSs have over metal or plastic stents is that removal is not require and reduce the need for repeated stent insertion. But the slightly lower radial force of BDS may be its main shortcoming and a post-implant problem. Thus, strengthening support of BDS is a content of the research in the future. BDSs are often temporarily effective in esophageal stricture to relieve dysphagia. In the future, it can be expect that biodegradable drug-eluting stents (DES will be available to treat benign esophageal stricture, perforations or leaks with additional use as palliative modalities for treating malignant esophageal stricture, as the bridge to surgery or to maintain luminal patency during neoadjuvant chemoradiation.

  17. Constitutive modeling of shock response of PTFE

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Eric N [Los Alamos National Laboratory; Reanyansky, Anatoly D [DSTO, AUSTRALIA; Bourne, Neil K [AWE, UK; Millett, Jeremy C F [AWE, UK

    2009-01-01

    The PTFE (polytetrafluoroethylene) material is complex and attracts attention of the shock physics researchers because it has amorphous and crystalline components. In turn, the crystalline component has four known phases with the high pressure transition to phase III. At the same time, as has been recently studied using spectrometry, the crystalline region is growing with load. Stress and velocity shock-wave profiles acquired recently with embedded gauges demonstrate feature that may be related to impedance mismatches between the regions subjected to some transitions resulting in density and modulus variations. We consider the above mentioned amorphous-to-crystalline transition and the high pressure Phase II-to-III transitions as possible candidates for the analysis. The present work utilizes a multi-phase rate sensitive model to describe shock response of the PTFE material. One-dimensional experimental shock wave profiles are compared with calculated profiles with the kinetics describing the transitions. The objective of this study is to understand the role of the various transitions in the shock response of PTFE.

  18. Percutaneous biliary drainage and stenting

    International Nuclear Information System (INIS)

    Totev, M.

    2012-01-01

    stents for benign strictures. In cases of malignant obstruction, stents are placed as a palliative measure only if the tumor is unresectable. Various stents are approved for use in the biliary system, including self-expanding and balloon-mounted stents. Tumor ingrowth through the stent, proximal or distal tumor overgrowth, and biliary sludge can cause stent obstruction. Covered stents are now being investigated to overcome the problem of tumor ingrowth. The stent is usually placed at an interval of a few days after percutaneous biliary drainage (PBD), though in cases of uncomplicated percutaneous transhepatic cholangiography (PTC), the stent procedure can be accomplished at the same time. Through our institutional experience and literature overview, we will provide a review outlining the vast array of biliary stenting for both benign and malignant disease. We provided a thorough, concise, and informative review and show that the decompression of the biliary system by drainage or biliary stents is well tolerated by the patients procedure that provide an excellent and minimally invasive palliation, mainly in malignant obstructive jaundice.

  19. Method of radiation degradation of PTFE under vacuum conditions

    Energy Technology Data Exchange (ETDEWEB)

    Korenev, Sergey E-mail: sergey_korenev@steris.com

    2004-10-01

    A new method of radiation degradation of Polytetrafluoroethylene (PTFE) under vacuum conditions is considered in this report. The combination of glow gas discharge and electrical surface discharge (on surface and inside PTFE) increases the efficiency of thermal-radiation degradation. The main mechanism of this degradation method consists of the breaking of C-C and C-F bonds. The vacuum conditions allow decreasing of the concentration of toxic compounds, such as a HF. Experimental results for degradation of PTFE are presented.

  20. Method of radiation degradation of PTFE under vacuum conditions

    Science.gov (United States)

    Korenev, Sergey

    2004-09-01

    A new method of radiation degradation of Polytetrafluoroethylene (PTFE) under vacuum conditions is considered in this report. The combination of glow gas discharge and electrical surface discharge (on surface and inside PTFE) increases the efficiency of thermal-radiation degradation. The main mechanism of this degradation method consists of the breaking of C-C and C-F bonds. The vacuum conditions allow decreasing of the concentration of toxic compounds, such as a HF. Experimental results for degradation of PTFE are presented.

  1. Effect of gamma radiation on graphite - PTFE dry lubrication system

    Science.gov (United States)

    Singh, Sachin; Tyagi, Mukti; Seshadri, Geetha; Tyagi, Ajay Kumar; Varshney, Lalit

    2017-12-01

    An effect of gamma radiation on lubrication behavior of graphite -PTFE dry lubrication system has been studied using (TR-TW-30L) tribometer with thrust washer attachment in plane contact. Different compositions of graphite and PTFE were prepared and irradiated by gamma rays. Gamma radiation exposure significantly improves the tribological properties indicated by decrease in coefficient of friction and wear properties of graphite -PTFE dry lubrication system. SEM and XRD analysis confirm the physico-chemical modification of graphite-PTFE on gamma radiation exposure leading to a novel dry lubrication system with good slip and anti friction properties.

  2. [E-PTFE Membrane for the Management of Perforated Corneal Ulcer].

    Science.gov (United States)

    Pahor, D; Pahor, A

    2016-10-01

    Purpose: To present the surgical management of perforated corneal ulcer using PRECLUDE® Pericardial Membrane, composed of expanded polytetrafluoroethylene (e-PTFE; GORE-TEX®), as an alternative surgical procedure in patients at high risk of graft rejections and to evaluate side effects for a prolonged period. Patients and Methods: The study included all patients who were admitted to our department and underwent surgical repair of perforated corneal ulcer with the e-PTFE membrane between 2010 and 2015. In total, 8 patients (8 eyes) were enrolled. Medical records of all patients were retrospectively reviewed. The operation was performed under peribulbar anaesthesia. Non-absorbable, microporous, watertight 0.1 mm thick e-PTFE membrane was used to close the corneal ulcer. The membrane was cut to overlap the defect adequately and to achieve the desired tissue attachment without preparing the conjunctiva or superficial trephination of the cornea. The membrane was fixed to the healthy cornea with several non-absorbable sutures (Prolene® 10.0), in order to achieve the proper stress without wrinkling. Results: Five of 8 patients were treated for systemic immunological diseases. Sjögren's syndrome was diagnosed in 2 patients, granulomatosis with polyangiitis in one, vasculitis with a history of previous sclerokeratitis in one and systemic lupus erythematosus in one. In 2 patients, corneal perforation was observed as a complication of corneal infection and in one patient as a late complication of a severe chemical burn. Corneal perforations were successfully covered with e-PTFE membrane in all patients. E-PTFE membrane was well tolerated in all patients and the eye was always preserved. After 3 to 4 months, the membrane was removed in 7 patients. The underlying cornea was thin, firm, stable and vascularised. In one patient with Sjögren's syndrome, the e-PTFE membrane is still in place. Conclusion: Surgical management of perforated corneal ulcer using E-PTFE membrane

  3. Square Stent: A New Self-Expandable Endoluminal Device and Its Applications

    International Nuclear Information System (INIS)

    Pavcnik, Dusan; Uchida, Barry; Timmermans, Hans; Keller, Frederick S.; Roesch, Josef

    2001-01-01

    The square stent is a new, simply constructed, self-expanding device that has recently been described. Compared with other stents, the square stent has a minimal amount of metal and thus requires a smaller-diameter catheter for introduction. Despite the small amount of metal present, the square stent has adequate expansile force. We have been evaluating the square stent for various interventional applications. In addition to the basic square stent, combinations of square stents and coverings for square stents were developed and evaluated to expand its uses and indications. One of the coverings tested is a new biomaterial: small intestinal submucosa (SIS). This paper will discuss the various applications of the square stent, which include a retrievable inferior vena cava filter, vascular occluder, graft adapter, and venous and aortic valves. In addition, we will review the important properties of SIS as a covering for the square stent

  4. Migrated esophageal stent posing a challenge for ventilation

    Directory of Open Access Journals (Sweden)

    Nita D'souza

    2017-01-01

    Full Text Available Self-expandable esophageal stents are being commonly used for palliative treatment in advanced esophageal cancer patients to relieve dysphagia, prevent tracheoesophageal fistula, and facilitate symptomatic betterment. The modern covered stents reduce the ingrowth of the tumor but have seen an increase in the incidence of stent migrations. We report a rather complicated presentation of an esophageal stent for esophageal dilatation and a challenging management of a difficult tracheostomy.

  5. Simulations of Self-Expanding Braided Stent Using Macroscopic Model of NiTi Shape Memory Alloys Covering R-Phase

    Czech Academy of Sciences Publication Activity Database

    Frost, Miroslav; Sedlák, Petr; Kruisová, Alena; Landa, Michal

    2014-01-01

    Roč. 23, č. 7 (2014), s. 2584-2590 ISSN 1059-9495 R&D Projects: GA ČR GA14-15264S; GA ČR(CZ) GP14-28306P; GA ČR GA13-13616S Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100761203 Program:M Institutional support: RVO:61388998 Keywords : braided stent * numerical simulation * R-phase * shape memory alloys Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.998, year: 2014 http://link.springer.com/article/10.1007/s11665-014-0966-z

  6. Properties of PTFE tape as a semipermeable membrane in fluorous reactions

    OpenAIRE

    Brendon A. Parsons; Olivia Lin Smith; Myeong Chae; Veljko Dragojlovic

    2015-01-01

    Summary In a PTFE tape phase-vanishing reaction (PV-PTFE), a delivery tube sealed with PTFE tape is inserted into a vessel which contains the substrate. The reagent diffuses across the PTFE tape barrier into the reaction vessel. PTFE co-polymer films have been found to exhibit selective permeability towards organic compounds, which was affected by the presence of solvents. In this study, we attempted to establish general trends of permeability of PTFE tape to different compounds and to better...

  7. Study of PTFE wick structure applied to loop heat pipe

    International Nuclear Information System (INIS)

    Wu, Shen-Chun; Gu, Tzu-Wei; Wang, Dawn; Chen, Yau-Ming

    2015-01-01

    This study investigated the use of sintered PTFE (polytetrafluoroethylene) particles as the wick material of loop heat pipe (LHP), taking advantage of PTFE's low thermal conductivity to reduce the heat leakage problem during LHP's operation. Different PTFE particle sizes were tried to find the one that resulted in the best wick; LHP performance tests were then conducted, and PTFE's potential for application to LHP was examined. Using PTFE particles ranging from 300–500 μm in size, the best wick properties were effective pore radius of 1.7 μm, porosity of 50%, and permeability of 6.2 × 10 −12  m 2 . LHP performance tests showed that, under typical electronic devices' operating temperature of 85 °C, the heat load reached 450 W, the thermal resistance was 0.145 °C/W, and the critical heat load (dryout heat load) reached 600 W. Compared to LHP with a nickel wick, LHP with a PTFE wick had a significantly lower operating temperature, indicating reduced heat leakage during operation, while having comparable performance; also, during the manufacturing process, a PTFE wick required lower sintering temperature, needed shorter sintering time, and had no need for hydrogen gas during sintering. The results of this study showed that, for high heat transfer capacity cooling devices, PTFE wicks possess great potential for applications to LHPs. - Highlights: • The performances of PTFE and nickel wicks in LHP are comparable for the first time. • PTFE wick allows for lower operating temperature and thus pressure in LHP system. • A wick requiring lower temperature and manufacturing cost and less time was made. • PTFE wick has potential to replace metal wick and enhance performance of LHP

  8. Dacron or PTFE for above-knee femoropopliteal bypass. a multicenter randomised study

    DEFF Research Database (Denmark)

    Jensen, L P; Lepäntalo, M; Fossdal, J E

    2007-01-01

    To compare polytetrafluorethylene (PTFE) and polyester grafts (Dacron) for above knee femoropopliteal bypass.......To compare polytetrafluorethylene (PTFE) and polyester grafts (Dacron) for above knee femoropopliteal bypass....

  9. 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.

  10. Diaphragms obtained by radiochemical grafting in PTFE

    International Nuclear Information System (INIS)

    Nenner, T.; Fahrasmane, A.

    1984-01-01

    Diaphragms for alkaline water electrolysis are prepared by radiochemical grafting of PTFE fabric with styrene, which is later on sulfonated, or with acrylic acid. The diaphragms obtained are mechanically resistant to potash at temperatures up to 200 0 C, but show some degrafting, which limits the lifetime. The sulfonated styrene group has been found to be more stable in electrolysis than the acrylic acid. In both cases, the incorporation of a cross-linking agent like divinyl benzene improves the lifetime of the diaphragms. Electrolysis during 500 hours at 120 0 C and 10 kAm 2 could be performed. (author)

  11. Fully covered self-expanding metal stents in the management of difficult common bile duct stones Prótesis metálicas autoexpandibles totalmente recubiertas en el tratamiento de coledocolitiasis difíciles

    Directory of Open Access Journals (Sweden)

    Jesús García-Cano

    2013-01-01

    Full Text Available Background and objectives: plastic biliary stents are often used after an ERCP session without complete common bile duct stones (CBDS extraction. Sometimes, the volume of biliary drainage with these stents may be insufficient. We present our experience with the use of fully covered self-expanding metal stents (FCSEMS in the setting of incomplete CBDS extraction. Patients and methods: after an ERCP session with difficult CBDS not completely removed, biliary FCSEMS (Wallflex were inserted in some patients when it was deemed that biliary sphincterotomy and a single plastic stent would not provide an adequate drainage. Results: a retrospective study was performed. Biliary FCSEMS were inserted in 29 patients, mean age 81 years. CBDS could not be extracted through a biliary sphincterotomy due to its large size (n = 18 or because of the presence of inflammatory distal strictures (n = 11. The greatest biliary drainage with shortest ERCP time was considered mandatory due to clinical instability of patients and/or poor tolerance to conscious sedation administered by the endoscopist. Successful biliary drainage was obtained in all cases. FCSEMS were removed after a median of 199.5 days in 16 patients with a complete CBDS extraction in 15 (93.7%. FCSEMS were not removed in the remaining 13 patients due to their clinical condition, and a wait-and-see strategy was undertaken. Conclusions: in selected cases, utilization of removable FCSEMS can be a good option for a quick and adequate biliary drainage in the setting of difficult CBDS. Because of the higher cost of these stents its use needs to be individualized.Introducción y objetivos: las prótesis biliares plásticas suelen emplearse tras una sesión de CPRE sin extracción completa de coledocolitiasis. En ocasiones, el calibre de drenaje con estas prótesis puede ser insuficiente. Presentamos nuestra experiencia en la utilización de prótesis metálicas autoexpandibles totalmente recubiertas (PMATR en

  12. ESR study on free radicals trapped in crosslinked polytetrafluoroethylene (PTFE)

    International Nuclear Information System (INIS)

    Oshima, Akihiro; Tabata, Yoneho; Seguchi, Tadao

    1997-01-01

    Free radicals in crosslinked PTFE which formed by 60 Co γ-rays irradiation at 77 K and at room temperature were studied by electron spin resonance (ESR) spectroscopy. The crosslinked PTFE specimens with different crosslinking density were prepared by electron beam irradiation in the molten state. The ESR spectra observed in the irradiated crosslinked PTFE are much different from those in non-crosslinked PTFE (virgin); a broad singlet component increases with increasing the crosslinking density, G-value of radicals is much higher in crosslinked PTFE than in non-crosslinked one. Free radicals related to the broad component are trapped in the non-crystalline region of crosslinked PTFE and rather stable at room temperature, whereas radicals trapped in amorphous non-crosslinked PTFE are unstable at room temperature. It is thought that most of free radicals trapped in the crosslinked PTFE are formed in the crosslinked amorphous region. The trapped radicals decays around 383 K (110 o C) due to the molecular motion of α-relaxation. (Author)

  13. 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

  14. Properties of PTFE tape as a semipermeable membrane in fluorous reactions

    Directory of Open Access Journals (Sweden)

    Brendon A. Parsons

    2015-06-01

    Full Text Available In a PTFE tape phase-vanishing reaction (PV-PTFE, a delivery tube sealed with PTFE tape is inserted into a vessel which contains the substrate. The reagent diffuses across the PTFE tape barrier into the reaction vessel. PTFE co-polymer films have been found to exhibit selective permeability towards organic compounds, which was affected by the presence of solvents. In this study, we attempted to establish general trends of permeability of PTFE tape to different compounds and to better describe the process of solvent transport in PV-PTFE bromination reactions. Though PTFE tape has been reported as impermeable to some compounds, such as dimethyl phthalate, solvent adsorption to the tape altered its permeability and allowed diffusion through channels of solvent within the PTFE tape. In this case, the solvent-filled pores of the PTFE tape are chemically more akin to the adsorbed solvent rather than to the PTFE fluorous structure. The solvent uptake effect, which was frequently observed in the course of PV-PTFE reactions, can be related to the surface tension of the solvent and the polarity of the solvent relative to the reagent. The lack of pores in bulk PTFE prevents solvents from altering its permeability and, therefore, bulk PTFE is impermeable to most solvents and reagents. However, bromine, which is soluble in liquid fluorous media, diffused through the bulk PTFE. A better understanding of the PTFE phase barrier will make it possible to further optimize the PV-PTFE reaction design.

  15. Modification of PTFE nanopowder by controlled electron beam irradiation: A useful approach for the development of PTFE coupled EPDM compounds

    Directory of Open Access Journals (Sweden)

    2008-04-01

    Full Text Available Low-temperature reactive mixing of controlled electron beam modified Polytetrafluoroethylene (PTFE nanopowder with Ethylene-Propylene-Diene-Monomer (EPDM rubber produced PTFE coupled EPDM rubber compounds with desired physical properties. The radiation-induced chemical alterations in PTFE nanopowder, determined by electron spin resonance (ESR and Fourier transform infrared (FTIR spectroscopy, showed increasing concentration of radicals and carboxylic groups (–COOH with increasing irradiation dose. The morphological variations of the PTFE nanopowder including its decreasing mean agglomerate size with the absorbed dose was investigated by particle size and scanning electron microscopy (SEM analysis. With increasing absorbed dose the wettability of the modified PTFE nanopowder determined by contact angle method increased in accordance with the (–COOH concentration. Transmission electron microscopy (TEM showed that modified PTFE nanopowder is obviously enwrapped by EPDM. This leads to a characteristic compatible interphase around the modified PTFE. Crystallization studies by differential scanning calorimetry (DSC also revealed the existence of a compatible interphase in the modified PTFE coupled EPDM.

  16. Evaluation of the short- and long-term effectiveness and safety of fully covered self-expandable metal stents for drainage of pancreatic fluid collections: results of a Spanish nationwide registry.

    Science.gov (United States)

    Vazquez-Sequeiros, Enrique; Baron, Todd H; Pérez-Miranda, Manuel; Sánchez-Yagüe, Andres; Gornals, Joan; Gonzalez-Huix, Ferran; de la Serna, Carlos; Gonzalez Martin, Juan Angel; Gimeno-Garcia, Antonio Z; Marra-Lopez, Carlos; Castellot, Ana; Alberca, Fernando; Fernandez-Urien, Ignacio; Aparicio, Jose Ramon; Legaz, Maria Luisa; Sendino, Oriol; Loras, Carmen; Subtil, Jose Carlos; Nerin, Juan; Perez-Carreras, Mercedes; Diaz-Tasende, Jose; Perez, Gustavo; Repiso, Alejandro; Vilella, Angels; Dolz, Carlos; Alvarez, Alberto; Rodriguez, Santiago; Esteban, Jose Miguel; Juzgado, Diego; Albillos, Agustin

    2016-09-01

    Initial reports suggest that fully covered self-expandable metal stents (FCSEMSs) may be better suited for drainage of dense pancreatic fluid collections (PFCs), such as walled-off pancreatic necrosis. The primary aim was to analyze the effectiveness and safety of FCSEMSs for drainage of different types of PFCs in a large cohort. The secondary aim was to investigate which type of FCSEMS is superior. This was a retrospective, noncomparative review of a nationwide database involving all hospitals in Spain performing EUS-guided PFC drainage. From April 2008 to August 2013, all patients undergoing PFC drainage with an FCSEMS were included in a database. The main outcome measurements were technical success, short-term (2 weeks) and long-term (6 months) effectiveness, adverse events, and need for surgery. The study included 211 patients (pseudocyst/walled-off pancreatic necrosis, 53%/47%). The FCSEMSs used were straight biliary (66%) or lumen-apposing (34%). Technical success was achieved in 97% of patients (95% confidence interval [CI], 93%-99%). Short-term- and long-term clinical success was obtained in 94% (95% CI, 89%-97%) and 85% (95% CI, 79%-89%) of patients, respectively. Adverse events occurred in 21% of patients (95% CI, 16%-27%): infection (11%), bleeding (7%), and stent migration and/or perforation (3%). By multivariate analysis, patient age (>58 years) and previous failed drainage were the most important factors associated with negative outcome. An FCSEMS is effective and safe for PFC drainage. Older patients with a history of unsuccessful drainage are more likely to fail EUS-guided drainage. The type of FCSEMS does not seem to influence patient outcome. Copyright © 2016 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

  17. 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

  18. Influence of Iliac Stenotic Lesions on Blood Flow Patterns Near a Covered Endovascular Reconstruction of the Aortic Bifurcation (CERAB) Stent Configuration

    NARCIS (Netherlands)

    Jebbink, Erik Groot; Engelhard, Stefan; Lajoinie, Guillaume; de Vries, Jean-Paul P.M.; Versluis, Michel; Reijnen, Michel M.P.J.

    2017-01-01

    Purpose: To investigate the effect of distal stenotic lesions on flow patterns near a covered endovascular reconstruction of the aortic bifurcation (CERAB) configuration used in the treatment of aortoiliac occlusive disease. Method: Laser particle image velocimetry measurements were performed using

  19. Treatment of malignant gastroduodenal obstruction with using a newly designed complex expandable nitinol stent: initial experiences

    International Nuclear Information System (INIS)

    Jung, Mi Hee; Ko, Ji Ho; Lee, Eun Jung; Oh, Kyeng Seung; Huh, Jin Do; Cho, Young Duk; Park, Seun Ja; Jung, Gyoo Sik

    2005-01-01

    We wanted to evaluate the usefulness of a new type of a complex expandable nitinol stent that was designed to reduce the stent's propensity to migration during the treatment of malignant gastroduodenal obstructions. Two types of expandable nitinol stent were constructed by weaving a single thread of 0.2mm nitinol wire in a tubular configuration: an uncovered stent 18mm in diameter and a covered stent 16mm in diameter. Both ends of the covered stent were fabricated by coaxially inserting the covered stent into the tubular uncovered stent and then attaching the two stents together with using nylon monofilament. Under fluoroscopic guidance, the stent was placed in 29 consecutive patients (20 men and 9 women, mean age: 65 years) who were suffering with malignant gastric outlet obstruction (n=20), duodenal obstruction (n=6) or combined obstruction (n=3). Clinical improvement was assessed by comparing the food intake capacity before and after the procedure. The complications were investigated during the follow up period. Stent placement was successful in all the patients. After stent placement, the symptoms improved in all but one patient. During the follow up, stent migration occurred in one patient (3%) at 34 days after the procedure. Despite the stent migration, the patient was able to resume a soft diet. Six patients developed recurrent symptoms of obstruction with tumor overgrowth at a mean of 145 days after the procedure; all the patients underwent coaxial placement of an additional stent with good results. One patient showed recurrence of obstruction due to tumor in-growth, and this was treated by placement of a second stent. Two patients with stent placement in the duodenum suffered from jaundice 26 days and 65 days, respectively, after their procedures. Placement of the newly designed complex expandable nitinol stent seems to be effective for the palliative treatment of malignant gastroduodenal obstructions. The new stent also seems to help overcome the

  20. Treatment of malignant gastroduodenal obstruction with using a newly designed complex expandable nitinol stent: initial experiences

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Mi Hee; Ko, Ji Ho; Lee, Eun Jung; Oh, Kyeng Seung; Huh, Jin Do; Cho, Young Duk; Park, Seun Ja [College of Medicine, Kosin University, Busan (Korea, Republic of); Jung, Gyoo Sik [Ulsan Hospital, Ulsan (Korea, Republic of)

    2005-12-15

    We wanted to evaluate the usefulness of a new type of a complex expandable nitinol stent that was designed to reduce the stent's propensity to migration during the treatment of malignant gastroduodenal obstructions. Two types of expandable nitinol stent were constructed by weaving a single thread of 0.2mm nitinol wire in a tubular configuration: an uncovered stent 18mm in diameter and a covered stent 16mm in diameter. Both ends of the covered stent were fabricated by coaxially inserting the covered stent into the tubular uncovered stent and then attaching the two stents together with using nylon monofilament. Under fluoroscopic guidance, the stent was placed in 29 consecutive patients (20 men and 9 women, mean age: 65 years) who were suffering with malignant gastric outlet obstruction (n=20), duodenal obstruction (n=6) or combined obstruction (n=3). Clinical improvement was assessed by comparing the food intake capacity before and after the procedure. The complications were investigated during the follow up period. Stent placement was successful in all the patients. After stent placement, the symptoms improved in all but one patient. During the follow up, stent migration occurred in one patient (3%) at 34 days after the procedure. Despite the stent migration, the patient was able to resume a soft diet. Six patients developed recurrent symptoms of obstruction with tumor overgrowth at a mean of 145 days after the procedure; all the patients underwent coaxial placement of an additional stent with good results. One patient showed recurrence of obstruction due to tumor in-growth, and this was treated by placement of a second stent. Two patients with stent placement in the duodenum suffered from jaundice 26 days and 65 days, respectively, after their procedures. Placement of the newly designed complex expandable nitinol stent seems to be effective for the palliative treatment of malignant gastroduodenal obstructions. The new stent also seems to help overcome the

  1. Pseudoaneurisme på arteria carotis interna behandlet med stent

    DEFF Research Database (Denmark)

    Benian, Cemil; Wagner, Aase; Cortsen, Marie

    2013-01-01

    Extracranial internal carotid artery aneurysms (EACIAs) are rare. Untreated they have a high stroke rate. Traditionally the treatment has been surgery or endovascular intervention with coils. Both are associated with relatively high complication rates. Another treatment option is endovascular int...... intervention with covered stent, which provides one-step closure of the aneurysm. As in the case story it can be complicated with in-stent occlusion. Therefore we recommend balloon occlusion test before treatment of EACIAs with covered stent....

  2. 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

  3. 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.

  4. Treatment Approaches to Urinary Stones Caused by Forgotten DJ Stents

    Directory of Open Access Journals (Sweden)

    Ergun Alma

    2015-03-01

    Full Text Available Ureteral DJ stents have been used widely for years in urology practice. With increased use, complications have been increased and forgotton stents have started to cause problems. The most common complications are early pain and irritative symptoms. Late complications are bacterial colonization and stone formation because of the biofilm covering the stents. Treatment for a forgotten stent varies on many factors, such as stent localization and stone formation. In this article, we aimed to discuss our clinic approach on two different cases in light to current literature. [Cukurova Med J 2015; 40(Suppl 1: 58-63

  5. Use of fully covered self-expanding metal stents for the management of benign biliary conditions Utilización de prótesis metálicas autoexpandibles totalmente recubiertas en procesos biliares benignos

    Directory of Open Access Journals (Sweden)

    J. García-Cano

    2010-09-01

    Full Text Available Background and aim: biliary self-expanding metal stents (SEMS have the advantage of being inserted undeployed with very small sizes and provide, when fully opened, large diameters for biliary drainage. However, their use in benign conditions has been very limited, mainly because of difficulty in their extraction. We present our initial experience with a fully covered SEMS (Wallflex for the management of benign problems of the bile duct. Patients and methods: in a prospective study, stents of 8 mm in diameter and 4, 6 or 8 cm long were inserted by means of ERCP. These SEMS were chosen when according to medical judgement it was thought that diameters greater than 10 French (3.3 mm were needed for proper biliary drainage. Stents were extracted also endoscopically, several months later when deemed clinically appropriate. Results: twenty biliary SEMS were inserted. Reasons for insertion were: large intrahepatic biliary fistula after hydatid cyst surgery (1, perforation of the papillary area following endoscopic sphincterotomy (2, coaxial insertion to achieve patency in obstructed uncovered stents inserted in benign conditions (3, benign strictures (7, multiple and large common bile duct stones that could not be extracted because of tapering and stricturing of the distal common bile duct (7. In all cases, successful biliary drainage was achieved and there were no complications from insertion. Stents were easily extracted after a mean time of 132 days (36-270 in place. Complete resolution of biliary problems was obtained in 14 patients (70%. Conclusions: in our initial experience, the fully covered Wallflex biliary stent was removed without any complication after being in place in the common bile duct for a mean time of over four months. Therefore, it could be used in the management of benign biliary conditions.Introducción y objetivo: las prótesis metálicas autoexpandibles biliares (PMAB tienen la ventaja de introducirse plegadas con calibres muy

  6. Annealing dependent evolution of columnar nanostructures in RF magnetron sputtered PTFE films for hydrophobic applications

    Science.gov (United States)

    Tripathi, S.; De, Rajnarayan; Maidul Haque, S.; Divakar Rao, K.; Misal, J. S.; Prathap, C.; Das, S. C.; Patidar, Manju M.; Ganesan, V.; Sahoo, N. K.

    2018-01-01

    Present communication focuses on a relatively less explored direction of producing rough polytetrafluoroethylene (PTFE) surfaces for possible hydrophobic applications. The experiments were carried out to make rough PTFE films without losing much of the transmission, which is an important factor while designing futuristic solar cell protection covers. After annealing temperature optimization, as grown RF magnetron sputtered PTFE films (prepared at 160 W RF power) were subjected to vacuum annealing at 200 °C for different time durations ranging from 1 to 4 h. The films show morphological evolution exhibiting formation and growth of columnar nanostructures that are responsible for roughening of the films due to annealing induced molecular migration and rearrangement. In agreement with this, qualitative analysis of corresponding x-ray reflectivity data shows modification in film thickness, which may again be attributed to the growth of columns at the expense of the atoms of remaining film molecules. However, the observations reveal that the film annealed at 200 °C for 2 h gives a combination of patterned columnar structures and reasonable transmission of >85% (in 500-1000 nm wavelength range), both of which are deteriorated when the films are annealed either at high temperature beyond 200 °C or for long durations >3 h. In addition, attenuated total reflection-Fourier transform infrared spectroscopy results reveal that the molecular bonds remain intact upon annealing at any temperature within the studied range indicating the stable nature of the films.

  7. 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.

  8. Basic Knowledge about Metal Stent Development

    Directory of Open Access Journals (Sweden)

    Seok Jeong

    2016-03-01

    Full Text Available Biliary self-expandable metal stents (SEMS, a group of non-vascular stents, have been used in the palliative management of biliary obstruction around the world. However, there are still unmet needs in the clinical application of biliary SEMS. Comprehensive understanding of the SEMS is required to resolve the drawbacks and difficulties of metal stent development. The basic structure of SEMS, including the materials and knitting methods of metal wires, covering materials, and radiopaque markers, are discussed in this review. What we know about the physical and mechanical properties of the SEMS is very important. With an understanding of the basic knowledge of metal stents, hurdles such as stent occlusion, migration, and kinking can be overcome to develop more ideal SEMS.

  9. Stent graft placement for dysfunctional arteriovenous grafts

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Gyeong Sik [Dept. of Radiology, CHA Bundang Medical Center, College of Medicine, CHA University, Seongnam (Korea, Republic of); Shin, Byung Seok; Ohm, Joon Young; Ahn, Moon Sang [Chungnam National University Hospital, Daejeon (Korea, Republic of)

    2015-07-15

    This study aimed to evaluate the usefulness and outcomes of stent graft use in dysfunctional arteriovenous grafts. Eleven patients who underwent stent graft placement for a dysfunctional hemodialysis graft were included in this retrospective study. Expanded polytetrafluoroethylene covered stent grafts were placed at the venous anastomosis site in case of pseudoaneurysm, venous laceration, elastic recoil or residual restenosis despite the repeated angioplasty. The patency of the arteriovenous graft was evaluated using Kaplan-Meier analysis. Primary and secondary mean patency was 363 days and 741 days. Primary patency at 3, 6, and 12 months was 82%, 73%, and 32%, respectively. Secondary patency at the 3, 6, 12, 24, and 36 months was improved to 91%, 82%, 82%, 50%, and 25%, respectively. Fractures of the stent graft were observed in 2 patients, but had no effect on the patency. Stent graft placement in dysfunctional arteriovenous graft is useful and effective in prolonging graft patency.

  10. Coated stents to prevent restenosis in coronary heart disease

    Directory of Open Access Journals (Sweden)

    Hagen, Anja

    2005-11-01

    Full Text Available Background: In-stent-restenosis (ISR is considered to be an essential limiting factor of stenting in coronary heart disease (CHD. The development of coated stents has raised expectations on substantial lowering restenosis after stenting with decreasing the rate of restenosis and a reduction in the rate of clinical events. Objectives: The present analysis addresses the questions on medical effectiveness and cost-effectiveness of the use of various coated stent types in CHD. Methods: The literature was searched in December 2004 in the most relevant medical and economic databases. The medical evaluation was conducted on the basis of published RCT. The data from the studies regarding various angiographic, sonographic and clinical endpoints were checked for methodical quality and summarised in meta-analyses. Within the scope of economic evaluation the primary studies were analysed and modelling was performed, applying clinical effect estimates from the meta-analyses of the medical evaluation and current estimates of German costs. Results: Medical evaluation: Ten different stenttypes were used in the included 26 RCT. The results for heparin, silicon-carbide, carbon and PTFE coated stenttypes could not reveal any significant differences between the medical effectiveness of coated and uncoated stents. The application of sirolimus, paclitaxel, everolimus and 7-hexanoyltaxol eluting stents showed a significant lower restenosis at 6-9 months with decrease in the rate of restenosis for polymer-based sirolimus, paclitaxel and 7-hexanoyltaxol eluting stents. In contrast, the use of gold-coated and actinomycin-D eluting stents was associated with a significantly higher restenosis. The polymer-based sirolimus and paclitaxel eluting stents also showed a significant and considerable reduction in the rate of repeated percutaneous revascularisations at 6-12 months (3.5% vs. 19.7%; p<0.0001, RR=0.19 [95%CI: 0.11; 0.33] and 3.5% vs. 12.2%; p<0.0001, RR=0.30 [95%CI: 0

  11. Studying the Effect of the Concentration of PTFE Nanoparticles on the Tribological Behavior of Ni-P-PTFE Composite Coatings

    Directory of Open Access Journals (Sweden)

    Hamid Rahmati

    2015-10-01

    Full Text Available In the past 30 years, electroless nickel (EN plating has grown to such proportions that these coatings and their applications are now found underground, in outer space, and in a myriad of areas in between. Moreover, in order to further improve the mechanical and tribological properties of the nickel-phosphorous (Ni-P coatings, Ni-P/PTFE composite coatings can be obtained, which provides even greater friction behavior and lubricity than the one naturally occurring in the nickel-phosphorous alloy deposit. In this paper, The Ni-P-PTFE coating was deposited on mild carbon steel surface via electroless deposition process. The friction behavior and wear mechanisms of Ni-P-PTFE nanocomposite coating were studied at different concentrations of PTFE. Frictional behavior was examined using a pin on disk wear test method. Surface morphology and worn surface was evaluated using field emission scanning electron microscopy (FESEM and energy dispersive spectroscopy (EDS analysis. The results showed that the incorporation of PTFE nanoparticles can reduce the wear rate of Ni-P coating from 33.07×10-6 mm3/Nm to 12.46×10-6 mm3/Nm for the Ni-P PTFE containing 10 g/l PTFE and decrease the friction coefficient from 0.64 to 0.2. Thus the tribological behavior of Ni-P coating is much improved in the presence of PTFE nanoparticles and 10 g/l is the optimized concentration of PTFE in the electroless bath.

  12. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  14. BRDF Calibration of Sintered PTFE in the SWIR

    Science.gov (United States)

    Georgiev, Georgi T.; Butler, James J.

    2009-01-01

    Satellite instruments operating in the reflective solar wavelength region often require accurate and precise determination of the Bidirectional Reflectance Distribution Function (BRDF) of laboratory-based diffusers used in their pre-flight calibrations and ground-based support of on-orbit remote sensing instruments. The Diffuser Calibration Facility at NASA's Goddard Space Flight Center is a secondary diffuser calibration standard after NEST for over two decades, providing numerous NASA projects with BRDF data in the UV, Visible and the NIR spectral regions. Currently the Diffuser Calibration Facility extended the covered spectral range from 900 nm up to 1.7 microns. The measurements were made using the existing scatterometer by replacing the Si photodiode based receiver with an InGaAs-based one. The BRDF data was recorded at normal incidence and scatter zenith angles from 10 to 60 deg. Tunable coherent light source was setup. Broadband light source application is under development. Gray-scale sintered PTFE samples were used at these first trials, illuminated with P and S polarized incident light. The results are discussed and compared to empirically generated BRDF data from simple model based on 8 deg directional/hemispherical measurements.

  15. PTFE-ALUMINUM films serve as neutral density filters

    Science.gov (United States)

    Burks, H. D.

    1966-01-01

    Polytetrafluoroethylene /PTFE/ films coated with aluminum films act as neutral density filters in the wavelength range 0.3 to 2.1 microns. These filters are effective in the calibration of photometric systems.

  16. Degradation and crosslinking of PTFE due to irradiation

    International Nuclear Information System (INIS)

    Tutiya, Mituaki

    1995-01-01

    In this report, we summarized all our experimental results concerning about the effects of Co-60 γ rays irradiation on polytetrafluoroethylene (PTFE). The NMR spectra, the mechanical properties and others of PTFE were measured. The increase in the degree of crystallinity, the lowering of the 19degC transition temperature and that of the melting temperature due to irradiation were observed. The effect of post-irradiation heat treatment were also observed. In each case, the main causes of these effects were attributed to the radiation-induced main chain scission. In the case of PTFE irradiated at 320-360degC in vacuum, we found that the effect of radiation-induced crosslinking were observed. By using our new theories, these experimental results which were measured in the crystalline and the amorphous regions of the irradiated PTFE were discussed, and a satisfactory agreement between the theories and the experiments was obtained. (author)

  17. Impact of lubrication on the tribological behaviour of PTFE ...

    Indian Academy of Sciences (India)

    bronze and bronze + molybdenum disulfide (MoS2) were considered. These composites were ... the PTFE composites have significantly been reduced in the lubricated condition ... there are no strong bonds between the fillers and the matrix in.

  18. Polyester composite versus PTFE in laparoscopic ventral hernia repair.

    Science.gov (United States)

    Colon, Modesto J; Telem, Dana A; Chin, Edward; Weber, Kaare; Divino, Celia M; Nguyen, Scott Q

    2011-01-01

    Both polyester composite (POC) and polytetrafluoroethylene (PTFE) mesh are commonly used for laparoscopic ventral hernia repair. However, sparse information exists comparing perioperative and long-term outcome by mesh repair. A prospective database was utilized to identify 116 consecutive patients who underwent laparoscopic ventral hernia repair at The Mount Sinai Hospital from 2004-2009. Patients were grouped by type of mesh used, PTFE versus POC, and retrospectively compared. Follow-up at a mean of 12 months was achieved by telephone interview and office visit. Of the 116 patients, 66 underwent ventral hernia repair with PTFE and 50 with POC mesh. Patients were well matched by patient demographics. No difference in mean body mass index (BMI) was demonstrated between the PTFE and POC group (31.8 vs. 32.5, respectively; P=NS). Operative time was significantly longer in the PTFE group (136 vs.106 minutes, PPTFE group and none in the POC group (P NS). No other major complications occurred in the immediate postoperative period (30 days). At a mean follow-up of 12 months, no significant difference was demonstrated between the PTFE and POC groups in hernia recurrence (3% vs. 2%), wound complications (1% vs. 0%), mesh infection, requiring removal (3% vs. 0%), bowel obstruction (3% vs. 2%), or persistent pain or discomfort (28% vs. 32%), respectively (P=NS). Our study demonstrated no significant association between types of mesh used and postoperative complications. In the 12-month follow-up, no differences were noted in hernia recurrence.

  19. Magnetorheological fluid based on thixotropic PTFE-oil organogel

    Science.gov (United States)

    Zhang, Hansong; Yan, Hua; Hu, Zhide; Yang, Jianjian; Niu, Fanghao

    2018-04-01

    Polytetrafluoroethylene (PTFE) micropowders were employed in this work to fabricate PTFE-oil organogel, then carbonyl iron particles were dispersed in this thixotropic organogel to prepare magnetorheological fluids without any other additives. By performing a comparative investigation of MRFs' performances, enhanced magnetorheological response, suspension stability and tribological performance were obtained contrast to pure silicon oil based MRFs. The experimental results revealed a changeable viscosity of organogel, considerable increases in thixotropy also can be observed with the increase of PTFE content. Sedimentation tests demonstrated a much better suspension stability of MRFs based on organogel, suggesting that the internal network microstructures formed by hydrogen bonds between PTFE microparticles and oil molecular chains are likely to impose the gaps among magnetic particles thus hinder the particle aggregation and sedimentation. Moreover, a critical PTFE volume fraction about 4.7 vol% was recognized in this study, lower content organogels tended to display enhanced yield stresses contrast to pure silicon oil based MRFs while high content organogels showed slightly lower ones. It may suggest a compromise between nonmagnetic particle adsorption and the reinforcement effect of network microstructures. The adsorption is likely to decrease the saturation magnetization of carbonyl iron particles and to hinder the formation of field-induced chains, however, the reinforcement effect tends to strengthen these magnetic chains. Besides, the tribological tests confirmed the lubricant effects of PTFE-oil organogel by acquiring rather sharp decreases in friction coefficients of organogel based MRFs especially in the presence of magnetic field.

  20. Improved patency and reduced intimal hyperplasia in PTFE grafts with luminal immobilized heparin compared with standard PTFE grafts at six months in a sheep model.

    Science.gov (United States)

    Pedersen, G; Laxdal, E; Ellensen, V; Jonung, T; Mattsson, E

    2010-06-01

    The aim of this study was to compare the performance of polytetrafluoroethylene (PTFE) grafts with luminal coating of immobilized heparin to that of standard PTFE grafts at six months. Twenty-eight common carotid arteries in fourteen sheep were bypassed with heparin-coated PTFE grafts (6 mm diameter, 6 cm length) on one side and standard PTFE grafts on the other. The grafts were explanted after six months. The thickness of intimal hyperplasia (IH) in open grafts was measured with histomorphometrical methods. Two of 14 heparinized PTFE grafts and nine of 14 grafts in the control PTFE-group were occluded at explantation (P=0.006). Six-month patency rates for heparinized PTFE grafts and for standard PTFE grafts were 86% and 36%, respectively. Mean graft anastomotic IH thickness in open grafts were 0.074 mm for heparinized PTFE grafts and 0.259 mm for PTFE-grafts (P=0.006). PTFE grafts with luminal coating containing immobilized heparin had significantly better patency and recruited less intimal hyperplasia than standard PTFE grafts at six months.

  1. 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

  2. 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

  3. Anchoring barbs and balloon expandable stents: what is the risk of perforation and failed stent deployment?

    Science.gov (United States)

    Bown, M J; Harrison, G J; How, T V; Brennan, J A; Fisher, R K; Vallabhaneni, S R; McWilliams, R G

    2012-09-01

    Balloon expandable stents may on occasion be deployed in close proximity to the anchoring barbs of endovascular grafts. The aim of this study was to determine the risk and effect of balloon perforation by anchoring barbs and to assess whether these risks are different if the balloon is protected by a covered stent mounted upon it. A bench-top model was developed to mimic the penetration of anchoring barbs into the lumen of medium sized blood vessels. The model allowed variation of angle and depth of vessel penetration. Both bare balloons and those with covered stents mounted upon them were tested in the model to determine whether there was a risk of perforation and which factors increased or decreased this risk. All combinations of barb angle and depth caused balloon perforation but this was most marked when the barb was placed perpendicular to the long axis of the balloon. When the deployment of covered stents was attempted balloon perforation occurred in some cases but full stent deployment was achieved in all cases where the perforation was in the portion of the balloon covered by the stent. The only situation in which stent deployment failed was where the barb was intentionally placed in the uncovered portion of the balloon. This resulted in only partial deployment of the stent. Balloon rupture is a distinct possibility when deploying balloon-expandable stents in close proximity to anchoring barbs. Care should be taken in this circumstance to ensure that the barb is well away from the uncovered portion of the balloon. Copyright © 2012 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  4. The Scandinavian Propaten(®) trial - 1-year patency of PTFE vascular prostheses with heparin-bonded luminal surfaces compared to ordinary pure PTFE vascular prostheses - a randomised clinical controlled multi-centre trial

    DEFF Research Database (Denmark)

    Lindholt, J S; Gottschalksen, B; Johannesen, N

    2011-01-01

    To compare 1-year potencies' of heparin-bonded PTFE [(Hb-PTFE) (Propaten(®))] grafts with those of ordinary polytetraflouroethylene (PTFE) grafts in a blinded, randomised, clinically controlled, multi-centre study.......To compare 1-year potencies' of heparin-bonded PTFE [(Hb-PTFE) (Propaten(®))] grafts with those of ordinary polytetraflouroethylene (PTFE) grafts in a blinded, randomised, clinically controlled, multi-centre study....

  5. Stent placement of gastroenteric anastomoses formed by magnetic compression.

    Science.gov (United States)

    Cope, C; Clark, T W; Ginsberg, G; Habecker, P

    1999-01-01

    To evaluate the use of stents for prolonging the patency of gastroenteric anastomoses (GEA) induced by magnet compression. Rare earth magnets were inserted perorally and serially in 15 dogs so as to mate across the gastric and jejunal walls. After magnet excretion, the resulting GEA was identified endoscopically, dilated (n = 1), and stented with bare (n = 2) or partially covered (n = 6) flared 10-mm or 12-mm Z stents. The GEA was followed at 2-4-week intervals for patency; malfunctioning shunts were irrigated, or dilated with angioplasty balloons. Gross and histologic examination of the anastomotic tissues was performed in 14 animals. Magnet pairs were excreted in 5-7 days. Of the 19 magnet placements in 15 animals, stent placement was not possible because of early GEA closure (n = 6), failure to locate (n = 2), pancreatic abscess (n = 1), and magnet perforation with peritonitis (n = 1). Estimated duration of GEA patency was 19 days after balloon dilation, 40-64 days with bare Z stents, and 58-147 days (mean, 90 days) with partially covered Z stents. Shunt function was commonly hindered by bezoars. Stent narrowing or occlusion was caused by tissue overgrowth through bare stents (n = 2), between covered stent struts and through partially detached membrane (n = 2). Serious morbidity (n = 2) was due to malpositioned magnets across the pancreas in one animal and gastric perforation in the other. One dog was euthanized because of unsuspected kidney infection. Partially covered stents significantly extend the anatomic patency rate of magnetic GEA to 7 weeks or more. Functional patency is frequently impaired by bezoars. Ongoing improvements in covered stent design should provide longer-term GEA patency.

  6. 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.

  7. Stent implantation into the tracheo-bronchial system in rabbits: histopathologic sequelae in bare metal vs. drug-eluting stents.

    Science.gov (United States)

    Sigler, Matthias; Klötzer, Julia; Quentin, Thomas; Paul, Thomas; Möller, Oliver

    2015-12-01

    Stent implantation into the tracheo-bronchial system may be life-saving in selected pediatric patients with otherwise intractable stenosis of the upper airways. Following implantation, significant tissue proliferation may occur, requiring re-interventions. We sought to evaluate the effect of immunosuppressive coating of the stents on the extent of tissue proliferation in an animal model. Bare metal and sirolimus-coated stents (Bx Sonic and Cypher Select, Johnson & Johnson, Cordis) were implanted into non-stenotic lower airways of New Zealand white rabbits (weight 3.1 to 4.8 kg). Three stents with sirolimus coating and six bare metal stents could be analyzed by means of histology and immunohistochemistry 12 months after implantation. On a macroscopic evaluation, all stents were partially covered with a considerable amount of whitish tissue. Histologically, these proliferations contained fiber-rich connective tissue and some fibromuscular cells without significant differences between both stent types. The superficial tissue layer was formed by typical respiratory epithelium and polygonal cells. Abundant lymphocyte infiltrations and moderate granulocyte infiltrations were found in both groups correspondingly, whereas foreign-body reaction was more pronounced around sirolimus-eluting stents. After stent implantation in the tracheo-bronchial system of rabbits, we found tissue reactions comparable to those seen after stent implantation into the vascular system. There was no difference between coated and uncoated stents with regard to quality and quantity of tissue proliferation. We found, however, a significantly different inflammatory reaction with a more pronounced foreign-body reaction in sirolimus-coated stents. In our small series, drug-eluting stents did not exhibit any benefit over bare metal stents in an experimental setting.

  8. Proton exchange membranes prepared by grafting of styrene/divinylbenzene into crosslinked PTFE membranes

    International Nuclear Information System (INIS)

    Li Jingye; Ichizuri, Shogo; Asano, Saneto; Mutou, Fumihiro; Ikeda, Shigetoshi; Iida, Minoru; Miura, Takaharu; Oshima, Akihiro; Tabata, Yoneho; Washio, Masakazu

    2005-01-01

    Thin PTFE membranes were prepared by coating the PTFE dispersion onto the aluminum films. Thus the thin crosslinked PTFE (RX-PTFE) membranes were obtained by means of electron beam irradiation above the melting temperature of PTFE under oxygen-free atmosphere. The RX-PTFE membranes were pre-irradiated and grafted by styrene with or without divinylbenzene (DVB) in liquid phase. The existence of DVB accelerated the initial grafting rate. The styrene grafted RX-PTFE membranes are white colored, on the other hand, the styrene/DVB grafted RX-PTFE membranes are colorless. The proton exchange membranes (PEMs) were obtained by sulfonating the grafted membranes using chlorosulfonic acid. The ion exchange capacity (IEC) values of the PEMs ranging from 1.5 to 2.8 meq/g were obtained. The PEMs made from the styrene/DVB grafted membranes showed higher chemical stability than those of the styrene grafted membranes under oxidative circumstance

  9. Alveolar Ridge Preservation with nc-HA and d-PTFE Membrane: A Clinical, Histologic, and Histomorphometric Study.

    Science.gov (United States)

    Laurito, Domenica; Lollobrigida, Marco; Gianno, Francesca; Bosco, Sandro; Lamazza, Luca; De Biase, Alberto

    Alveolar ridge preservation has become a very common procedure following tooth extraction. This study presents a clinical, histologic, and histomorphometric analysis of postextraction bone changes using nanocrystalline hydroxyapatite (nc-HA) and exposed high-density polytetrafluoroethylene (d-PTFE) membrane. A total of 10 extraction sockets were treated. Clinical measurements were taken after tooth extraction with a customized acrylic stent to ensure the same measurement points. At 6 months, clinical measurements were repeated and bone specimens taken. An overall bone reduction was observed. The histologic and histomorphometric analysis revealed newly formed bone (25.92% ± 18.78%), soft tissue (28.55% ± 9.73%), and residual graft particles (15.43% ± 11.08%). Further studies are necessary to evaluate the efficacy of this technique over the long term.

  10. Carotid Angioplasty and Stenting

    Science.gov (United States)

    Carotid angioplasty and stenting Overview Carotid angioplasty (kuh-ROT-id AN-jee-o-plas-tee) and stenting ... to better see and examine the blood vessels. Food and medications You'll receive instructions on what ...

  11. Thermal desorption study of physical forces at the PTFE surface

    Science.gov (United States)

    Wheeler, D. R.; Pepper, S. V.

    1987-01-01

    Thermal desorption spectroscopy (TDS) of the polytetrafluoroethylene (PTFE) surface was successfully employed to study the possible role of physical forces in the enhancement of metal-PTFE adhesion by radiation. The thermal desorption spectra were analyzed without assumptions to yield the activation energy for desorption over a range of xenon coverage from less than 0.1 monolayer to more than 100 monolayers. For multilayer coverage, the desorption is zero-order with an activation energy equal to the sublimation energy of xenon. For submonolayer coverages, the order for desorption from the unirradiated PTFE surface is 0.73 and the activation energy for desorption is between 3.32 and 3.36 kcal/mol; less than the xenon sublimation energy. The effect of irradiation is to increase the activation energy for desorption to as high as 4 kcal/mol at low coverage.

  12. 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.

  13. Expandable metallic stent: experimental and clinical experience in tracheobronchial tree

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ho Young; Lee, Sang Young; Chung, Jin Young; Han, Young Min; Kim, Jong Soo; Choi, Ki Chul; Hong, Ki Whan; Rhee, Yang Kun [Chonbuk National University Medical School, Jeonju (Korea, Republic of)

    1991-05-15

    To maintain or reestablish an adequate airway in a patient with tracheobronchial narrowing coming from various causes, we constructed self-expanding metallic stents the same way Gianturco did, using them in 2 patients after an experimental study with rabbits. Twenty stents (10mm in diameter fully expanded and 20mm in length) were introduced into the trachea or bronchi of 10 Newzealand rabbits (weight, 2.5-3.0kg) through a 8.5 French Teflon sheath. No difficulties were encountered in the placement of the stents. At follow-up (4-12 weeks), no stent showed migration. Three rabbits died of pneumonia or bronchial perforation. Histologically, mucosal inflammation was noted at the sites of stent placement, and stent wires were covered by proliferated epithelium with intact cilia. During the last 4 months, 2 stents were used in 2 patients, one in a patient with endobronchial tuberculosis (3.0cm in length and 1.0cm in diameter fully expanded) and the other (3.0cm in length and 1.5cm in diameter) in a patient with a subglottic mass. In both patients the stents were successfully placed. Just after the placement of the stents dyspnea subsided in both patients, and there was no mortality or morbidity. These stents seem to be effective in the treatment of tracheobronchial stenosis, tracheomalacia, and airway collapse following tracheal reconstruction.

  14. Expandable metallic stent: experimental and clinical experience in tracheobronchial tree

    International Nuclear Information System (INIS)

    Song, Ho Young; Lee, Sang Young; Chung, Jin Young; Han, Young Min; Kim, Jong Soo; Choi, Ki Chul; Hong, Ki Whan; Rhee, Yang Kun

    1991-01-01

    To maintain or reestablish an adequate airway in a patient with tracheobronchial narrowing coming from various causes, we constructed self-expanding metallic stents the same way Gianturco did, using them in 2 patients after an experimental study with rabbits. Twenty stents (10mm in diameter fully expanded and 20mm in length) were introduced into the trachea or bronchi of 10 Newzealand rabbits (weight, 2.5-3.0kg) through a 8.5 French Teflon sheath. No difficulties were encountered in the placement of the stents. At follow-up (4-12 weeks), no stent showed migration. Three rabbits died of pneumonia or bronchial perforation. Histologically, mucosal inflammation was noted at the sites of stent placement, and stent wires were covered by proliferated epithelium with intact cilia. During the last 4 months, 2 stents were used in 2 patients, one in a patient with endobronchial tuberculosis (3.0cm in length and 1.0cm in diameter fully expanded) and the other (3.0cm in length and 1.5cm in diameter) in a patient with a subglottic mass. In both patients the stents were successfully placed. Just after the placement of the stents dyspnea subsided in both patients, and there was no mortality or morbidity. These stents seem to be effective in the treatment of tracheobronchial stenosis, tracheomalacia, and airway collapse following tracheal reconstruction

  15. Gianturco-Rösch Z stents in tracheobronchial stenoses.

    Science.gov (United States)

    Petersen, B D; Uchida, B T; Barton, R E; Keller, F S; Rösch, J

    1995-01-01

    To evaluate expandable metallic Gianturco-Rösch Z (GRZ) stents for treatment of benign and malignant tracheobronchial stenoses. Six patients, ages 45-73 years, were treated for severe dyspnea with placement of GRZ stents. Three patients had benign tracheal lesions (one tracheomalacia, two postoperative) and received uncovered GRZ stents. Three patients had malignant stenoses at the level of the carina; one received an uncovered stent and the other two received silicone-covered GRZ stents. Two patients with benign lesions responded well to stent placement. One was asymptomatic for a year and then was lost to follow-up; the other improved substantially but died of end-stage lung disease 5 months after stent placement. A third patient with a benign high tracheal lesion did poorly; symptoms recurred secondary to inferior migration of a stent, which was removed surgically at 4 months. All patients with malignant lesions improved symptomatically after stent placement and remained without significant dyspnea until death (from 1 to 6 months). Expandable GRZ stents are promising devices for treatment of benign lesions and offer effective palliation of malignant tracheobronchial stenoses.

  16. 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.

  17. Radiologic placement of metallic esophageal stents: preliminary experience

    International Nuclear Information System (INIS)

    Good, S.; Asch, M.R.; Jaffer, N.; Casson, A.G.

    1997-01-01

    To assess the usefulness of covered, self expanding metallic stents for alleviating stricture associated with malignant esophageal lesions. Patients and methods: Self-expanding metallic stents were placed in 10 patients with dysphagia related to stricture caused by malignant esophageal lesions. The stents were placed fluoroscopically with local anesthesia, and patency of the esophageal lumen was assessed by barium study after the procedure. The patients were then followed clinically. Results: In all 10 cases patency of the lumen was renewed after stent placement. After the procedure 9 of the patients could tolerate a normal or near-normal diet; in the other patient esophageal perforation occurred, and clinical deterioration prevented oral intake of food. In one patient, 2 stents were needed because of the length of the stricture. Two patients experienced reflux after placement of the stent across the gastro-esophageal junction. Another patient had asymptomatic aspiration after stent placement in the proximal esophagus. In 2 patients, symptoms associated with tracheoesophageal fistula were relieved after placement of the stents. Six of the 10 patients died; mean survival after the procedure was 12 (range 1 to 56) weeks. The other 4 patients were alive at the time of writing, having survived for a mean of 7.5 (range 2 to 13) weeks; all of these patients tolerated a near-normal diet. Conclusions: The placement of covered, self-expanding metallic stents is a quick, effective method of palliating dysphagia related to stricture caused by malignant esophageal lesions. (author)

  18. [Successful correction with stent-graft of coronary artery rupture after angioplasty].

    Science.gov (United States)

    Demin, V V

    2003-01-01

    Rupture and perforation of coronary arteries complicate in average 0.5% of radiosurgical coronary interventions and often are accompanied by serious consequences and high mortality. According to-type of coronary perforation different methods of correction are used, ranging from conservative measures to urgent cardiosurgical interventions. Coronary stent-grafts with 'sandwich' type of construction ore composed from two metal stents and PTFE layer between them. Development of such stents enabled effective radioguided endovascular repair of coronary ruptures. The paper presents the first Russian experience of stout-graft implantation for coronary artery rupture occurred during direct stenting of proximal anterior descending artery and balloon angioplasty in distal segment. The rupture occurred probably because of wall fragility between affected segment and muscular bridge. Stent-graft JoStent 16 mm in length connected with 3-mm balloon was implanted with subsequent complete restitution of blood flow, resolution of pain syndrome and ECG normalization. Echocardiography in operative theatre and one day after surgery showed no intrapericardial fluid. Stent-graft devices for urgent implantation in cases of coronary rupture must be included into obligatory equipment of radiosurgical facilities.

  19. [Evaluation of stents in treating childhood benign esophageal strictures].

    Science.gov (United States)

    Reinshagen, K; Kähler, G; Manegold, B C; Waag, K-L

    2009-01-01

    Esophageal stenting is a popular of treatment of esophageal strictures in adults. It has also been described for children with benign strictures who did not respond to standard dilatation therapy. The aim of the study was to evaluate weather esophageal stents could be used safely and effectively in the treatment of benign esophageal strictures in children. From 1993 to 2005 stenting therapy was performed in 12 children with complicated esophageal strictures. Etiologies of the strictures were caustic burns in 9 patients, postoperative strictures due to complicated esophageal atresia in 2 patients and iatrogenic esophageal injury in 1 patient. Esophageal silicon tubi, covered retrievable expandable nitinol and plastic stents were placed endoscopically. The clinical course and the long term follow up were evaluated retrospectively The stents and tubi were placed in all patients without complications and were later removed successfully. 6 patients were treated with a self expanding plastic stent. The plastic stents showed a distinct tendency to migrate but in 5/6 patients esophageal stricture was treated successfully. 3 patients were treated by a covered self expanding nitinol stent. No migration occurred. One patient was asymptomatic after therapy, one required further dilatation therapy and the third had esophageal resection. 3 patients were treated by esophageal tubi. 2 patients required surgery in the follow up, one patient is asymptomatic. The use of stenting devices in children to treat benign esophageal strictures is safe and efficient. The self expanding plastic stents had the best long term results but required high compliance of parents and children due to the tendency of stent migration. Self expanding nitinol stents are more traumatic at the extraction procedure and are useful in patients with low compliance. Recurrence of strictures occurred most often after esophageal tubi possibly due to the lack of radial expansion.

  20. 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)

  1. Dosimetric properties of LIF:Mg,CuP+PTFE

    International Nuclear Information System (INIS)

    Gonzalez Martinez, P.R.; Azorin Nieto, J.; Ramirez Luna, A.

    1998-01-01

    The work presents the preparation method, as well as the characterization of the dosemeters of LiF;Mg,Cu+PTFE developed in the National Institute of Nuclear Investigations (ININ) Mexico, Among the carried out tests can mention, sensibility, detection threshold, equivalent of bottom, uniformity, reproducibility, dissipation, answer in function of the dose and kinetic parameters

  2. Creation and Validation of Sintered PTFE BRDF Targets & Standards.

    Science.gov (United States)

    Durell, Christopher; Scharpf, Dan; McKee, Greg; L'Heureux, Michelle; Georgiev, Georgi; Obein, Gael; Cooksey, Catherine

    2015-09-21

    Sintered polytetrafluoroethylene (PTFE) is an extremely stable, near-perfect Lambertian reflecting diffuser and calibration standard material that has been used by national labs, space, aerospace and commercial sectors for over two decades. New uncertainty targets of 2 % on-orbit absolute validation in the Earth Observing Systems community have challenged the industry to improve is characterization and knowledge of almost every aspect of radiometric performance (space and ground). Assuming "near perfect" reflectance for angular dependent measurements is no longer going to suffice for many program needs. The total hemispherical spectral reflectance provides a good mark of general performance; but, without the angular characterization of bidirectional reflectance distribution function (BRDF) measurements, critical data is missing from many applications and uncertainty budgets. Therefore, traceable BRDF measurement capability is needed to characterize sintered PTFE's angular response and provide a full uncertainty profile to users. This paper presents preliminary comparison measurements of the BRDF of sintered PTFE from several laboratories to better quantify the BRDF of sintered PTFE, assess the BRDF measurement comparability between laboratories, and improve estimates of measurement uncertainties under laboratory conditions.

  3. Novel management strategy for coronary steal syndrome: case report of occlusion of a LIMA graft side branch with a combination of drug-eluting and covered-stent deployment.

    LENUS (Irish Health Repository)

    Hynes, Brian G

    2009-11-01

    We report a novel percutaneous therapeutic approach to the management of suspected coronary artery steal syndrome resulting from a large side branch of the left internal mammary artery bypass graft, using a combination of coated and drug-eluting stents. We demonstrate the feasibility and long-term efficacy of this strategy in a case report.

  4. Peroxi-coagulation degradation of C.I. Basic Yellow 2 based on carbon-PTFE and carbon nanotube-PTFE electrodes as cathode

    International Nuclear Information System (INIS)

    Zarei, Mahmoud; Salari, Darioush; Niaei, Aligoli; Khataee, Alireza

    2009-01-01

    The electrochemical treatment of solutions containing C.I. Basic Yellow 2 (BY2) in aqueous solutions with carbon-PTFE (polytetrafluoroethylene) and carbon nanotube (CNT)-PTFE electrodes as cathode has been studied. The fabricated electrodes were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The amount of electrogenerated H 2 O 2 on the surface of these electrodes was investigated, too. The results showed that the amount of H 2 O 2 obtained with the CNT-PTFE electrode was nearly three times higher than that of carbon-PTFE electrode. The decolorization efficiency of BY2 in peroxi-coagulation process reached 62% and 96% in the first 10 min by carbon-PTFE and CNT-PTFE electrodes at 100 mA, respectively. The effect of operational parameters such as applied current, initial pH and initial dye concentration was studied in an attempt to reach higher decolorization efficiency. The degradation and mineralization of BY2 using CNT-PTFE electrode were followed by total organic carbon (TOC) and GC-MS analysis. The results of TOC measurements indicated that peroxi-coagulation with carbon-PTFE allowed 81% mineralization after 6 h of electrolysis; whereas peroxi-coagulation with CNT-PTFE yields 92% mineralization under the same conditions. GC-MS analysis verified the identity of intermediates and a reaction pathway based on them was proposed.

  5. Biomechanical comparison of expanded polytetrafluoroethylene (ePTFE) and PTFE interpositional patches and direct tendon-to-bone repair for massive rotator cuff tears in an ovine model.

    Science.gov (United States)

    McKeown, Andrew Dj; Beattie, Rebekah F; Murrell, George Ac; Lam, Patrick H

    2016-01-01

    Massive irreparable rotator cuff tears are a difficult problem. Modalities such as irrigation and debridement, partial repair, tendon transfer and grafts have been utilized with high failure rates and mixed results. Synthetic interpositional patch repairs are a novel and increasingly used approach. The present study aimed to examine the biomechanical properties of common synthetic materials for interpositional repairs in contrast to native tendon. Six ovine tendons, six polytetrafluoroethylene (PTFE) felt sections and six expanded PTFE (ePTFE) patch sections were pulled-to-failure to analyze their biomechanical and material properties. Six direct tendon-to-bone surgical method repairs, six interpositional PTFE felt patch repairs and six interpositional ePTFE patch repairs were also constructed in ovine shoulders and pulled-to-failure to examine the biomechanical properties of each repair construct. Ovine tendon had higher load-to-failure (591 N) and had greater stiffness (108 N/mm) than either PTFE felt (296 N, 28 N/mm) or ePTFE patch sections (323 N, 34 N/mm). Both PTFE felt and ePTFE repair techniques required greater load-to-failure (225 N and 177 N, respectively) than direct tendon-to-bone surgical repairs (147 N) in ovine models. Synthetic materials lacked several biomechanical properties, including strength and stiffness, compared to ovine tendon. Interpositional surgical repair models with these materials were significantly stronger than direct tendon-to-bone model repairs.

  6. Biodegradable stents for the treatment of refractory or recurrent benign esophageal stenosis.

    Science.gov (United States)

    Imaz-Iglesia, Iñaki; García-Pérez, Sonia; Nachtnebel, Anna; Martín-Águeda, Belén; Sánchez-Piedra, Carlos; Karadayi, Bilgehan; Demirbaş, Ali Rıza

    2016-06-01

    Esophageal stents are used for the treatment of refractory and recurrent dyphagias. In 2007, esophageal biodegradable stents (EBS) were authorised as an alternative to existing metal and plastic stents in Europe. The advantages claimed for EBS are fewer complications concerning tissue ingrowth, stent migration and stent removal. We performed a systematic review to evaluate the efficacy and safety of EBS compared to fully-covered self-expanding metal stents, self-expanding plastic stents, and esophageal dilation for the treatment of refractory or recurrent benign esophageal stenosis. Three comparative studies (one randomized controlled trial and two cohort studies) were assessed. The studies used different inclusion criteria, had a very small (sample) size and the quality of the evidence was very low. Expert commentary: The current evidence is insufficient to determine the relative efficacy or safety of esophageal biodegradable stents. The results of this systematic review should be updated once new evidence is available.

  7. Circumferential Stent Fracture: Novel Detection and Treatment with the Use of StentBoost

    OpenAIRE

    Ramegowda, Raghu T.; Chikkaswamy, Srinivas B.; Bharatha, Ashalatha; Radhakrishna, Jayashree; Krishnanaik, Geetha B.; Nanjappa, Manjunath C.; Panneerselvam, Arunkumar

    2012-01-01

    Circumferential stent fracture is extremely uncommon, and in rare cases, it can cause stent thrombosis. Recognizing stent fracture can be difficult on conventional fluoroscopy because of poor stent radiopacity. We found that StentBoost image acquisition yields improved visibility of stent struts, enabling the identification of stent fracture and the precise positioning of new stents over previously stented segments.

  8. Socket Preservation with d-PTFE Membrane: Histologic Analysis of the Newly Formed Matrix at Membrane Removal.

    Science.gov (United States)

    Laurito, Domenico; Cugnetto, Riccardo; Lollobrigida, Marco; Guerra, Fabrizio; Vestri, Annarita; Gianno, Francesca; Bosco, Sandro; Lamazza, Luca; De Biase, Alberto

    This study aimed to evaluate the efficacy of an exposed high-density polytetrafluoroethylene (d-PTFE) membrane in preventing epithelial migration in postextraction sockets. For this purpose, a histologic description of the newly formed soft tissue underlying the membrane is presented. The periodontal status of the adjacent teeth was also evaluated to assess the gingival response. Ten premolar extraction sockets were treated. After tooth extraction, the sockets were filled with nanocrystalline hydroxyapatite and covered with d-PTFE membranes. Subperiosteal pockets were created to ensure the stability of the membranes. Membranes were left intentionally exposed and were atraumatically removed after 28 days. At that time, a bioptic specimen of the newly formed soft tissue under the membranes was taken. All the histologic samples showed a dense connective tissue without epithelial cells and no signs of foreign body reaction. No significant variation of the periodontal indices was observed on the teeth adjacent to the extraction sites. The study results indicate that exposed d-PTFE membranes can prevent epithelial migration in healing sockets without consequences on the periodontal health.

  9. Use of retrievable self-expanding stent in treating childhood benign oesophageal stricture

    International Nuclear Information System (INIS)

    Yu Juming; Fan Guoping; Zhong Weixing; Zhu Ming

    2007-01-01

    Objective: To evaluate the methods and effect of retrievable self-expanding esophageal stent in treating benign esophageal stenosis of children. Methods: The covered retrievable expandable nitinol stents were placed in 10 children with corrosive esophageal stenosis and post-anastomotic stenosis, age ranged from 2 to 12 years, the dysphagia scores were 3, Barium esophagography was taken before the use of retrievable stent. Results: The stents were placed safely in all patients without complications and were successfully removed after all. After the stent placement, all patients could take solid food without dysphagia. During 6 to 12 months follow-up after the stent removal, all children could eat satisfactorily with the dysphagia score as 0. Conclusion: The use of covered retrievable expandable stent is effective and safe in treating childhood benign esophageal stenosis. (authors)

  10. The impact of precise robotic lesion length measurement on stent length selection: ramifications for stent savings.

    Science.gov (United States)

    Campbell, Paul T; Kruse, Kevin R; Kroll, Christopher R; Patterson, Janet Y; Esposito, Michele J

    2015-09-01

    Coronary stent deployment outcomes can be negatively impacted by inaccurate lesion measurement and inappropriate stent length selection (SLS). We compared visual estimate of these parameters to those provided by the CorPath 200® Robotic PCI System. Sixty consecutive patients who underwent coronary stent placement utilizing the CorPath System were evaluated. The treating physician assessed orthogonal images and provided visual estimates of lesion length and SLS. The robotic system was then used for the same measures. SLS was considered to be accurate when visual estimate and robotic measures were in agreement. Visual estimate SLSs were considered to be "short" or "long" if they were below or above the robotic-selected stents, respectively. Only 35% (21/60) of visually estimated lesions resulted in accurate SLS, whereas 33% (20/60) and 32% (19/60) of the visually estimated SLSs were long and short, respectively. In 5 cases (8.3%), 1 less stent was placed based on the robotic lesion measurement being shorter than the visual estimate. Visual estimate assessment of lesion length and SLS is highly variable with 65% of the cases being inaccurately measured when compared to objective measures obtained from the robotic system. The 32% of the cases where lesions were visually estimated to be short represents cases that often require the use of extra stents after the full lesion is not covered by 1 stent [longitudinal geographic miss (LGM)]. Further, these data showed that the use of the robotic system prevented the use of extra stents in 8.3% of the cases. Measurement of lesions with robotic PCI may reduce measurement errors, need for extra stents, and LGM. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Custom-made covered transjugular intrahepatic portosystemic shunt (TIPS) in an infant with trisomy 22 and biliary atresia

    International Nuclear Information System (INIS)

    Chlapoutaki, Chrysanthi Emmanouil; Franchi-Abella, Stephanie; Pariente, Daniele; Habes, Dalila

    2009-01-01

    We report an 8-month-old girl with portal hypertension secondary to biliary atresia. The decision to treat with TIPS was made at the age of 8 months due to recurrent variceal bleeding. The procedure was carried out with a 6-mm bare stent due to her small size. Radiological follow-up with Doppler US showed gradual stenosis and finally occlusion of the stent 80 days after implantation. Revision was performed with placement of an additional 6-mm expanded polytetrafluoroethylene (e-PTFE) stent-graft that had remained patent for 9 months, proving that in small children with a portal vein diameter less than 8 mm, the combination of a bare stent and stent-graft can provide excellent results. (orig.)

  12. Custom-made covered transjugular intrahepatic portosystemic shunt (TIPS) in an infant with trisomy 22 and biliary atresia

    Energy Technology Data Exchange (ETDEWEB)

    Chlapoutaki, Chrysanthi Emmanouil; Franchi-Abella, Stephanie; Pariente, Daniele [Bicetre Hospital University Paris XI, Assistance Publique Hopitaux de Paris, Department of Paediatric Radiology, Paris (France); Habes, Dalila [Bicetre Hospital University Paris XI, Assistance Publique Hopitaux de Paris, Pediatric Hepatology and National Reference Center for Biliary Atresia, Paris (France)

    2009-07-15

    We report an 8-month-old girl with portal hypertension secondary to biliary atresia. The decision to treat with TIPS was made at the age of 8 months due to recurrent variceal bleeding. The procedure was carried out with a 6-mm bare stent due to her small size. Radiological follow-up with Doppler US showed gradual stenosis and finally occlusion of the stent 80 days after implantation. Revision was performed with placement of an additional 6-mm expanded polytetrafluoroethylene (e-PTFE) stent-graft that had remained patent for 9 months, proving that in small children with a portal vein diameter less than 8 mm, the combination of a bare stent and stent-graft can provide excellent results. (orig.)

  13. Recurrent airway obstructions in a patient with benign tracheal stenosis and a silicone airway stent: a case report

    Science.gov (United States)

    Sriram, KB; Robinson, PC

    2008-01-01

    Airway stents (silicone and metal stents) are used to treat patients with benign tracheal stenosis, who are symptomatic and in whom tracheal surgical reconstruction has failed or is not appropriate. However airway stents are often associated with complications such as migration, granuloma formation and mucous hypersecretion, which cause significant morbidity, especially in patients with benign tracheal stenosis and relatively normal life expectancy. We report a patient who had frequent critical airway obstructions over 8 years due to granuloma and mucus hypersecretion in a silicone airway stent. The problem was resolved when the silicone stent was removed and replaced with a covered self expanding metal stent. PMID:18840299

  14. Modified nasolacrimal duct stenting

    International Nuclear Information System (INIS)

    Tian Min; Jin Mei; Chen Huanjun; Li Yi

    2008-01-01

    Objective: Traditional nasolacrimal duct stenting possesses some shortcoming including difficulty of pulling ball head guide wire from the nasal cavity with turbinate hypertrophy and nasal septal deviation. The new method of nose-oral tube track establishment can overcome the forementioned and increase the successful rate. Methods: 5 F catheter and arterial sheath were modified to be nasolacrimal duct stent delivery device respectively. Antegrade dacryocystography was taken firstly to display the obstructed site and followed by the modified protocol of inserting the guide wire through nasolacrimal duct and nasal cavity, and establishing the stent delivery track for retrograde stent placement. Results: 5 epiphora patients with failure implantation by traditional method were all succeeded through the modified stenting (100%). During 6-mouth follow-up, no serious complications and reocclusion occurred. Conclusion: The establishment of eye-nose-mouth-nose of external nasal guide wire track can improve the successful rate of nasolacrimal duct stenting. (authors)

  15. 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...

  16. Tracheal Penetration and Tracheoesophageal Fistula Caused by an Esophageal Self-Expanding Metallic Stent

    Directory of Open Access Journals (Sweden)

    Karan Madan

    2014-01-01

    Full Text Available Tracheal penetration of esophageal self-expanding metallic stents (SEMS with/without tracheoesophageal fistula (TEF formation is a rare occurrence. We report the case of a 66-year-old female patient with advanced esophageal squamous cell carcinoma who had undergone palliative esophageal stenting on three occasions for recurrent esophageal stent obstruction. On evaluation of symptoms of breathing difficulty and aspiration following third esophageal stent placement, tracheal erosion and TEF formation due to the tracheal penetration by esophageal stent were diagnosed. The patient was successfully managed by covered tracheal SEMS placement under flexible bronchoscopy.

  17. Experience of usage of forming rings and protective caps made of PTFE on the single-component implants

    Directory of Open Access Journals (Sweden)

    S. A. Chertov

    2014-04-01

    Full Text Available Relevance. The main reason that limits the usage of single-component implants, as compared with collapsible (two-component implants is the high risk of infectious and inflammatory complications in the postoperative period and problems in prosthetics in the esthetically important areas. Therefore, the usage of elements that contribute to healing of the mucous membrane in the early stages of implantation is particularly up-to-date. Work objective is to determine the clinical effectiveness of usage of forming rings and protective caps made of PTFE on the single-component implants in the prevention of peri-implant pathology on a one-step surgical implantation. Materials and methods of the investigation. For this work we used the treatment results of 24 patients with various dentition defects. According to the single-component implant procedure 52 single-component implants were mounted. The head of monolithic implants (38 p. were isolated by rings or caps made of PTFE. For comparison, 14 implants remained bare for 2-6 weeks before the temporary prosthesis. Postoperatively, subjective feelings were noted in patients, the presence or absence of pain complaints during the examination and palpation, the nature and extent of edema, the phenomena of inflammation around the implant neck were checked. At the stage of sutures removal the degree of soft plaque deposits on the healing elements and titanium implant heads was assessed. Results of the investigation and their discussion. No effects of mucosal hyperemia around the supporting elements made of PTFE were revealed, there was no soft and hard plaque on the rings and caps in most patients of the main group. In patients of the control group, on the contrary, the appearance of the biofilm that covered the head and the implant shoulder on all abutments, which were not protected by a ring or cap, was noted. The healing period of mucous membrane in patients of the control group was longer, the quality of

  18. Dosimetric characterization of KMgF3:Tb+PTFE

    International Nuclear Information System (INIS)

    Ramirez R, M. I.; Garcia S, L.; Villicana M, M.; Huirache A, R.; Apolinar C, J.; Gonzalez M, P. R.

    2017-10-01

    In this work the results obtained from the dosimetric characterization of the new radiation detectors of KMgF 3 :Tb+PTFE are presented. The host salt was obtained by means of the microwave technique, with the polycrystalline powder obtained, dosimeters were made in tablet form, using as Ptfe binder. The thermoluminescent response of these new detectors presented a linear behavior, in the dose range between 1 and 1000 Gy of 60 Co gamma radiation, the reproducibility test in the measurements, during ten cycles of heat treatment, irradiation and reading presented ± 3.7% Ds, in the stability test of thermoluminescent signal, during two months showed that the fading is practically null. Due to the results obtained, this new detector could be very useful for the dosimetry of ionizing radiation in different clinical applications. (Author)

  19. Robot-Assisted Antegrade In-Situ Fenestrated Stent Grafting

    International Nuclear Information System (INIS)

    Riga, Celia V.; Bicknell, Colin D.; Wallace, Daniel; Hamady, Mohamad; Cheshire, Nicholas

    2009-01-01

    To determine the technical feasibility of a novel approach of in-situ fenestration of aortic stent grafts by using a remotely controlled robotic steerable catheter system in the porcine model. A 65-kg pig underwent robot-assisted bilateral antegrade in-situ renal fenestration of an abdominal aortic stent graft with subsequent successful deployment of a bare metal stent into the right renal artery. A 16-mm iliac extension covered stent served as the porcine aortic endograft. Under fluoroscopic guidance, the graft was punctured with a 20-G customized diathermy needle that was introduced and kept in place by the robotic arm. The needle was exchanged for a 4 x 20 mm cutting balloon before successful deployment of the renal stent. Robot-assisted antegrade in-situ fenestration is technically feasible in a large mammalian model. The robotic system enables precise manipulation, stable positioning, and minimum instrumentation of the aorta and its branches while minimizing radiation exposure.

  20. Anastomotic leak after oesophagectomy and stent implantation: a systematic review

    Directory of Open Access Journals (Sweden)

    A.N. Kanatas

    2011-12-01

    Full Text Available Anastomotic leaks following oesophageal cancer resection have a high mortality. Stents have an established position in the palliation of dysphagia due to malignancy and in treating malignant perforation or fistula. They are increasingly used for benign conditions such as spontaneous oesophageal perforation with encouraging results. In this systematic review we examine the available evidence and attempt to define the role of stents in the management of oesophageal anastomotic leaks after resection for cancer. It is evident from the review that plastic- and metal-covered stents are an effective strategy for the treatment of anastomotic leaks. Vigilance is required as complications such as stent migration and incomplete sealing are not uncommon. Further clinical studies with greater methodological rigor in terms of sample size and study design may confirm that stents have an important contribution to make in the management of oesophageal anastomotic leak.

  1. Grade III Coronary Artery Perforation Following PCI and Unusual Stent Graft Delivery System

    Directory of Open Access Journals (Sweden)

    Sreckovic Miodrag

    2014-06-01

    Full Text Available Koronarne perforacije su retke ali izuzetno neugodne komlikacije perkutanih intervencija. Perforacije koronarnh arterija trećeg stepena po Elisu predstvaljaju najozbiljniju formu perforacija i zahtevaju hitno zbrinjavanje. Često je neophodno uraditi perikardiocentezu i primeniti brojne interventne tehnike kako bismo rešili perforaciju. Stentovi prekriveni politetrafluoroetilenom(PTFE postali su jedno od najčešće korišćenih perkutanih rešenja, ali su njihove mane visoki profil i slaba fleksibilnost. U našem slučaju, pokušali smo da poboljšamo plasiranje PTFE stenta montiranjem na metalni stent, koji smo iskoristili kao nosač.

  2. Robust Non-Wetting PTFE Surfaces by Femtosecond Laser Machining

    Directory of Open Access Journals (Sweden)

    Fang Liang

    2014-08-01

    Full Text Available Nature shows many examples of surfaces with extraordinary wettability, which can often be associated with particular air-trapping surface patterns. Here, robust non-wetting surfaces have been created by femtosecond laser ablation of polytetrafluoroethylene (PTFE. The laser-created surface structure resembles a forest of entangled fibers, which support structural superhydrophobicity even when the surface chemistry is changed by gold coating. SEM analysis showed that the degree of entanglement of hairs and the depth of the forest pattern correlates positively with accumulated laser fluence and can thus be influenced by altering various laser process parameters. The resulting fibrous surfaces exhibit a tremendous decrease in wettability compared to smooth PTFE surfaces; droplets impacting the virgin or gold coated PTFE forest do not wet the surface but bounce off. Exploratory bioadhesion experiments showed that the surfaces are truly air-trapping and do not support cell adhesion. Therewith, the created surfaces successfully mimic biological surfaces such as insect wings with robust anti-wetting behavior and potential for antiadhesive applications. In addition, the fabrication can be carried out in one process step, and our results clearly show the insensitivity of the resulting non-wetting behavior to variations in the process parameters, both of which make it a strong candidate for industrial applications.

  3. Tribological study of PTFE composites loaded with porcelain tile waste

    International Nuclear Information System (INIS)

    Oliveira, P.M.; Araujo Neto, A.P.; Souza, J.R.; Medeiros, J.T.N.

    2016-01-01

    The Brazilian northeast is one of the largest producers of clays that burn in the white form and disposal of tailings from the process of polishing the ceramic pieces of porcelain stands out as a major source of environmental degradation. This problem can be reduced by adding such material as filler in composites, in order to improve the mechanical properties of the polymeric matrix. Polytetrafluoroethylene (PTFE) is characterized as a good solid lubricant, because it has excellent properties such as low coefficient of friction (0.01 < μ < 0.1), thermal stability at high temperatures and chemical resistance. However, the pure PTFE has high wear rates (greater than 10-13m2/N) leading to early failures of various components. To reuse the Tailings of Porcelain (TP), composites of PTFE + TP were developed in three different compositions (85:15, 75:25 and 65:35). For this investigation the particle size distribution and some chemical characteristics of the tailings by testing XRD, XRF, SEM and EDS were performed, registering a large amount of silica, aluminum and other metals. Roughness, wettability and sclerometry also were performed. It was noted that the values of arithmetic average roughness, Ra, is higher for composites with higher percentage of TP, in addition they have a lower contact angle and higher surface energy to distilled water, characterized as hydrophilic. The results of energy of deformation provided by the sclerometry test were non-linear. (author)

  4. Scalable bonding of nanofibrous polytetrafluoroethylene (PTFE) membranes on microstructures

    Science.gov (United States)

    Mortazavi, Mehdi; Fazeli, Abdolreza; Moghaddam, Saeed

    2018-01-01

    Expanded polytetrafluoroethylene (ePTFE) nanofibrous membranes exhibit high porosity (80%-90%), high gas permeability, chemical inertness, and superhydrophobicity, which makes them a suitable choice in many demanding fields including industrial filtration, medical implants, bio-/nano- sensors/actuators and microanalysis (i.e. lab-on-a-chip). However, one of the major challenges that inhibit implementation of such membranes is their inability to bond to other materials due to their intrinsic low surface energy and chemical inertness. Prior attempts to improve adhesion of ePTFE membranes to other surfaces involved surface chemical treatments which have not been successful due to degradation of the mechanical integrity and the breakthrough pressure of the membrane. Here, we report a simple and scalable method of bonding ePTFE membranes to different surfaces via the introduction of an intermediate adhesive layer. While a variety of adhesives can be used with this technique, the highest bonding performance is obtained for adhesives that have moderate contact angles with the substrate and low contact angles with the membrane. A thin layer of an adhesive can be uniformly applied onto micro-patterned substrates with feature sizes down to 5 µm using a roll-coating process. Membrane-based microchannel and micropillar devices with burst pressures of up to 200 kPa have been successfully fabricated and tested. A thin layer of the membrane remains attached to the substrate after debonding, suggesting that mechanical interlocking through nanofiber engagement is the main mechanism of adhesion.

  5. Robust non-wetting PTFE surfaces by femtosecond laser machining.

    Science.gov (United States)

    Liang, Fang; Lehr, Jorge; Danielczak, Lisa; Leask, Richard; Kietzig, Anne-Marie

    2014-08-08

    Nature shows many examples of surfaces with extraordinary wettability,which can often be associated with particular air-trapping surface patterns. Here,robust non-wetting surfaces have been created by femtosecond laser ablation of polytetrafluoroethylene (PTFE). The laser-created surface structure resembles a forest of entangled fibers, which support structural superhydrophobicity even when the surface chemistry is changed by gold coating. SEM analysis showed that the degree of entanglement of hairs and the depth of the forest pattern correlates positively with accumulated laser fluence and can thus be influenced by altering various laser process parameters. The resulting fibrous surfaces exhibit a tremendous decrease in wettability compared to smooth PTFE surfaces; droplets impacting the virgin or gold coated PTFE forest do not wet the surface but bounce off. Exploratory bioadhesion experiments showed that the surfaces are truly air-trapping and do not support cell adhesion. Therewith, the created surfaces successfully mimic biological surfaces such as insect wings with robust anti-wetting behavior and potential for antiadhesive applications. In addition, the fabrication can be carried out in one process step, and our results clearly show the insensitivity of the resulting non-wetting behavior to variations in the process parameters,both of which make it a strong candidate for industrial applications.

  6. Wear resistant PTFE thin film enabled by a polydopamine adhesive layer

    International Nuclear Information System (INIS)

    Beckford, Samuel; Zou, Min

    2014-01-01

    The influence of a polydopamine (PDA) adhesive layer on the friction and wear resistance of polytetrafluoroethylene (PTFE) thin films coated on stainless steel was investigated. The friction and wear tests were carried out using a ball on flat configuration under a normal load of 50 g, sliding speed of 2.5 mm/s, and stroke length of 15 mm. It is found that the PDA/PTFE film is able to withstand approximately 500 times more rubbing cycles than the PTFE film alone. X-ray photoelectron spectroscopy (XPS) results show that a tenacious layer of PTFE remains adhered to the PDA layer, which enables the durability of the PDA/PTFE film. Because of the relatively low thickness of the film, PDA/PTFE shows great potential for use in applications where durable, thin films are desirable

  7. Study on poly-electrolyte membrane of crosslinked PTFE by radiation-grafting

    International Nuclear Information System (INIS)

    Sato, Kohei; Ikeda, Shigetoshi; Iida, Minoru; Oshima, Akihiro; Tabata, Yoneho; Washio, Masakazu

    2003-01-01

    Polymer electrolyte fuel cell membrane based on crosslinked polytetrafluoroethylene (PTFE) [RX-PTFE] has been processed by radiation-grafting with reactive styrene monomers by γ-rays under atmospheric circumstances, and the characteristic properties of the obtained membranes have been studied. The grafting yields of styrene monomer onto RX-PTFE, which have various crosslinking densities, were in the range of 5-100%. At the reaction period of 24 h, the grafting yields for RX-PTFE with low crosslinking density, which was reacted at 60 deg. C, achieved 94%. As a tendency, the lower grafting temperature gives higher grafting ratio of styrene onto RX-PTFE. Moreover, the yields of subsequent sulfonation for all samples were close to 100%. Mechanical properties were decreased with increasing grafting yields; especially the membrane with higher grafting yields was brittle. Ion exchange capacity of sulfonated RX-PTFE reached 1.1 meq/g while maintaining the mechanical properties

  8. Successful Treatment of Bronchoesophageal Fistula With Esophageal and Bronchial Stenting

    Directory of Open Access Journals (Sweden)

    Cheng-Yi Wang

    2011-04-01

    Full Text Available Bronchoesophageal fistula is reported in 5-10% of patients with esophageal cancer. In most of these cases, the insertion of a single stent, either a tracheobronchial or an esophageal stent, is sufficient to seal off the fistula. In this case we describe a 67-year-old man with esophageal cancer and complications of bronchoesophageal fistula, which resulted in repeated pneumonia and acute respiratory failure. Initially, two expandable metallic membranous esophageal stents were placed to cover the fistula. However, the esophageal stent failed to stop the air leak and dislodged into the stomach. Thereafter, a bronchial stent was placed at the right intermediate bronchus and successfully stopped the air leak. The patient was then weaned from the ventilator 1 week after the insertion of a bronchial stent. In conclusion, stenting in both the esophagus and airways should be considered when both are severely invaded by malignancy, when the airway is compressed, or when the fistula is insufficiently sealed by an esophageal stent.

  9. Surface modification of PTFE sheet by synchrotron radiation in the soft X-ray region

    International Nuclear Information System (INIS)

    Kato, Y.; Kanda, K.; Haruyama, Y.; Matsui, S.

    2004-01-01

    Full text: The surface properties of poly (tetrafluoroethylene) (PTFE) are changed by the exposure to synchrotron radiation (SR). We succeeded in controlling the wettability of the PTFE surface from hydrophobic to hydrophilic by varying the substrate temperature during the SR irradiation and found that the wettability was ascribable to microstructure and chemical composition of surface.In these previous works, oxygen atoms were found to inhabit on the hydrophobic surface of PTFE. In this study, we investigated the surface modification of PTFE from the SR exposure experiment under the O 2 gas atmosphere. The SR exposure to the PTFE sheet was carried out at beamline 6 (BL6) of the New- SUBARU. The PTFE sheet was irradiated to the white beam, ranging 50-1000 eV at BL6 at room temperature. The gas cell was mounted at the irradiation chamber. The O 2 gas pressure in the gas cell can be maintained at about 0.20 Pa during the SR exposure using 5mm φ hole window. The wettability of PTFE surface was evaluated by the contact angle of a small water drop. Contact angle was measured with the water drop of 1 μl using the contact angle meter. Fig.1 shows the SR dose dependence of contact angle of PTFE surface under the O 2 gas atmosphere and under the vacuum. Contact angle decreased monotonically with SR dose. The decrease rate of contact angle of the PTFE surface irradiated under the O 2 gas atmosphere was larger than that of the PTFE surface irradiated without O 2 gas. Therefore, the combination of O atom to the PTFE surface was enhanced by the O 2 gas in the reaction region. These results suggested that the bonding of O atom on the hydrophobic PTFE surface is dominantly produced in the sample chamber during SR irradiation, but not in the air atmosphere after the SR irradiation

  10. Enterocutaneous fistula associated with ePTFE mesh: case report and review of the literature.

    Science.gov (United States)

    Foda, M; Carlson, M A

    2009-06-01

    A case of enterocutaneous fistula secondary to the erosion of an expanded polytetrafluoroethylene (ePTFE) prosthesis into the jejunum is described. This case is unusual secondary to the long experience with ePTFE and the lack of published cases similar to this one. The technical details of this case reveal extenuating circumstances associated with the fistula formation, and it is concluded that this particular case does not provide sufficient evidence to implicate ePTFE, by itself, as an etiologic agent for gastrointestinal fistulization. In addition, the published safety record of ePTFE in abdominal wall surgery is reviewed.

  11. Nano-structuring of PTFE surface by plasma treatment, etching, and sputtering with gold

    International Nuclear Information System (INIS)

    Reznickova, Alena; Kolska, Zdenka; Hnatowicz, Vladimir; Svorcik, Vaclav

    2011-01-01

    Properties of pristine, plasma modified, and etched (by water and methanol) polytetrafluoroethylene (PTFE) were studied. Gold nanolayers sputtered on this modified PTFE have been also investigated. Contact angle, measured by goniometry, was studied as a function of plasma exposure and post-exposure aging times. Degradation of polymer chains was examined by etching of plasma modified PTFE in water or methanol. The amount of ablated and etched layer was measured by gravimetry. In the next step the pristine, plasma modified, and etched PTFE was sputtered with gold. Changes in surface morphology were observed using atomic force microscopy. Chemical structure of modified polymers was characterized by X-ray photoelectron spectroscopy (XPS). Surface chemistry of the samples was investigated by electrokinetic analysis. Sheet resistance of the gold layers was measured by two-point technique. The contact angle of the plasma modified PTFE decreases with increasing exposure time. The PTFE amount, ablated by the plasma treatment, increases with the plasma exposure time. XPS measurements proved that during the plasma treatment the PTFE macromolecular chains are degraded and oxidized and new –C–O–C–, –C=O, and –O–C=O groups are created in modified surface layer. Surface of the plasma modified PTFE is weakly soluble in methanol and intensively soluble in water. Zeta potential and XPS shown dramatic changes in PTFE surface chemistry after the plasma exposure, water etching, and gold deposition. When continuous gold layer is formed a rapid decrease of the sheet resistance of the gold layer is observed.

  12. Improved conductivity of carbon-nano-fiber (CNF)/polytetrafluoroethylene (PTFE) composite

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, Sarita; Kalra, G. S.; Pushkar, Vinay K.; Gill, Fateh Singh, E-mail: drfatehs@gmail.com [Graphic Era University, Bell Road, Clement Town, Dehradun (India); Panwar, Variz [School of Materials Science and Engineering, Gwangju Institute of Science Technology (GIST), Gwangju 500-712 (Korea, Republic of); Gupta, Himanshu; Pal, Pankaj K.; Pathak, Trilok K.; Purohit, L. P. [Gurukul Kangri University, Haridwar-249404 (India)

    2016-05-23

    A series of CNF/PTFE composite loaded with different weight % of CNFs as 0.01, 0.02, 0.03, 0.05, 1, 2, 3, 4, 5 into PTFE is fabricated. In this work, the 5wt% heat-treated CNFs were used as filler in PTFE. Current-voltage (I-V) study of the samples confirmed the samples as conducting composite. In scanning electron microscope (SEM) study, the conducting CNFs channels were observed from upper surface to inside throughout the polymer matrix. A sintered composite of 5 wt% loading of CNFs showed an improved conductivity and SEM image exhibited a good binding of CNFs into PTFE.

  13. Improved conductivity of carbon-nano-fiber (CNF)/polytetrafluoroethylene (PTFE) composite

    International Nuclear Information System (INIS)

    Chandra, Sarita; Kalra, G. S.; Pushkar, Vinay K.; Gill, Fateh Singh; Panwar, Variz; Gupta, Himanshu; Pal, Pankaj K.; Pathak, Trilok K.; Purohit, L. P.

    2016-01-01

    A series of CNF/PTFE composite loaded with different weight % of CNFs as 0.01, 0.02, 0.03, 0.05, 1, 2, 3, 4, 5 into PTFE is fabricated. In this work, the 5wt% heat-treated CNFs were used as filler in PTFE. Current-voltage (I-V) study of the samples confirmed the samples as conducting composite. In scanning electron microscope (SEM) study, the conducting CNFs channels were observed from upper surface to inside throughout the polymer matrix. A sintered composite of 5 wt% loading of CNFs showed an improved conductivity and SEM image exhibited a good binding of CNFs into PTFE.

  14. 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.

  15. Comparison of the performance of natural latex membranes prepared with different procedures and PTFE membrane in guided bone regeneration (GBR) in rabbits.

    Science.gov (United States)

    Moura, Jonas M L; Ferreira, Juliana F; Marques, Leonardo; Holgado, Leandro; Graeff, Carlos F O; Kinoshita, Angela

    2014-09-01

    This work assessed the performance of membranes made of natural latex extracted from Hevea brasiliensis prepared with three different methods: polymerized immediately after collection without the use of ammonia (L1); polymerized after preservation in ammonia solution (L2); and polymerized after storage in ammonia, followed by Soxhlet technique for the extraction of substances (L3). Polytetrafluoroethylene (PTFE) membrane was used as control. Two 10-mm diameter bone defects were surgically made in the calvaria of thirty adult male New Zealand rabbits. Defects (total n = 60) were treated with guided bone regeneration (GBR) using L1, L2, L3 or PTFE membranes (n = 15 for each membrane). Ten animals were euthanized after 7, 20 and 60 days postoperatively so that five samples (n = 5) of each treatment were collected at each time, and bone regeneration was assessed microscopically. The microscopic analysis revealed defects filled with blood clot and new bone formation at the margins of the defect in all 7-day samples, while 20-day defects were mainly filled with fibrous connective tissue. After 60 days defects covered with L1 membranes showed a significantly larger bone formation area in comparison to the other groups (P PTFE membranes was also investigated in six additional rabbits. The animals were subjected to the same surgical procedure for the confection of one 10-mm diameter bone defect that was treated with L1 (n = 3) or PTFE (n = 3). Fifty-three days later, a second surgery was performed to make a second defect, which was treated with the same type of membrane used in the first surgery. Seven days later, the animals were euthanized and samples analyzed. No differences among L1 and PTFE samples collected from sensitized and non-sensitized animals were found (P > 0.05, Kruskal-Wallis). Therefore, the results demonstrated that latex membranes presented performance comparable to PTFE membranes, and that L1 membranes induced higher bone formation. L1 and

  16. Endovascular stenting for treatment of complex intracranial aneurysms: preliminary outcome

    International Nuclear Information System (INIS)

    Huang Qinghai; Liu Jianmin; Xu Yi; Hong Bo; Zhao Wenyuan; Zhou Xiaoping

    2004-01-01

    Objective: To summarize the technique and efficiency of combined endovascular stenting and Guglielmi detachable coils (GDC) packing for the treatment of intracranial wide-necked bifurcation aneurysms and recanalized aneurysms. Methods: The coronary stents were implanted across the necks of 5 intracranial wide-necked aneurysms (two at bifurcation of ICA, one at basilar artery and two recanalized PcoA aneurysms). The porous stents covered the ostia of vital side branches and perforating vessels in three cases. Microcatheters were introduced into the aneurysmal sac through the stent mesh and then followed by GDCs embolizing the aneurysms. Results: The stents were deployed in parent artery in all cases. Total occlusion was obtained in 4 cases, while more than 90% in one case with patency of the parent arteries and vital perforating arteries. Follow-up angiography performed in all patients 3-6 months later revealed no intrastent stenosis. All the patients recovered well except III nerve palsy in one patient which diminished 3 months later. Conclusion: Endovaseular therapy combined stent implantation and microcoil placement maybe a valid alteration for the treatment of wide-necked bifurcation aneurysms and recanalized aneurysms, which shows promise clinical application in the future. The ostia of vital side branches covered with stents showed no effect on hemodynamics. (authors)

  17. 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...

  18. Novel biliary self-expanding metal stents: indications and applications.

    Science.gov (United States)

    Blero, Daniel; Huberty, Vincent; Devière, Jacques

    2015-03-01

    Endoscopic insertion of a self-expanding metal stent (SEMS) through a malignant common bile duct stricture is the first line of palliation for malignant jaundice. Patency of these stents remains a major concern. SEMS dysfunction can result from tumor ingrowth, overgrowth and/or clogging. Initial SEMS modifications involved covering the central part of the stent in order to reduce ingrowth and ultimately increase patency. Fully covered stents became available shortly after reports of their use in human patients. The potential removability and radial strength of SEMS have led to evaluation of their use in new indications including benign biliary strictures, post sphincterotomy bleeding and perforation. Other aspects of development include the addition of features such as anti-reflux valves, drug elution and spontaneous biodegradability. These aspects and their clinical implications are reviewed and discussed.

  19. 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.

  20. Palliative metallic stent placement for managing esophageal cancer of the aging

    International Nuclear Information System (INIS)

    Li Qnqi; Yin Huabin; Yue Wei; Ji Chengzhou; Yang Yufeng

    2000-01-01

    Objective: To evaluate the effectiveness of self-expanding metallic stent in the treatment of the old patients with malignant esophageal stricture. Methods: 32 old patients with malignant esophageal stricture were treated with covered self-expandable metallic stents, 32 stents were placed by X-TV guiding, without pre-dilatation of the stenosis by balloon catheter. Results: All 32 stents were successfully placed, the successful rate was 100%. All of the patients obtained the improvement of the food intake ability. No fatal stent-related complications occurred. The average survival time was 6.5 months. Conclusions: The covered self-expandable metallic stent is effective in the palliative management of malignant esophageal stricture of the aging

  1. Spectral Imaging for Intracranial Stents and Stent Lumen.

    Science.gov (United States)

    Weng, Chi-Lun; Tseng, Ying-Chi; Chen, David Yen-Ting; Chen, Chi-Jen; Hsu, Hui-Ling

    2016-01-01

    Application of computed tomography for monitoring intracranial stents is limited because of stent-related artifacts. Our purpose was to evaluate the effect of gemstone spectral imaging on the intracranial stent and stent lumen. In vitro, we scanned Enterprise stent phantom and a stent-cheese complex using the gemstone spectral imaging protocol. Follow-up gemstone spectral images of 15 consecutive patients with placement of Enterprise from January 2013 to September 2014 were also retrospectively reviewed. We used 70-keV, 140-keV, iodine (water), iodine (calcium), and iodine (hydroxyapatite) images to evaluate their effect on the intracranial stent and stent lumen. Two regions of interest were individually placed in stent lumen and adjacent brain tissue. Contrast-to-noise ratio was measured to determine image quality. The maximal diameter of stent markers was also measured to evaluate stent-related artifact. Two radiologists independently graded the visibility of the lumen at the maker location by using a 4-point scale. The mean of grading score, contrast/noise ratio and maximal diameter of stent markers were compared among all modes. All results were analyzed by SPSS version 20. In vitro, iodine (water) images decreased metallic artifact of stent makers to the greatest degree. The most areas of cheese were observed on iodine (water) images. In vivo, iodine (water) images had the smallest average diameter of stent markers (0.33 ± 0.17mm; P stent lumen (160.03 ±37.79; P stent-related artifacts of Enterprise and enhance contrast of in-stent lumen. Spectral imaging may be considered a noninvasive modality for following-up patients with in-stent stenosis.

  2. Removal of self expandable metallic airway stent: A rare case report

    Directory of Open Access Journals (Sweden)

    Rakesh K Chawla

    2013-01-01

    Full Text Available Covered self expandable metallic airway stents (SEMS have been used for benign tracheal stenosis, post intubation tracheal stenosis, tracheal burn or trauma, tracheo-broncho-malacia, and extrinsic compression of trachea. Their placement is considered to be permanent, with open surgery the only way to remove the stent, though there are few cases reports of their removal with the bronchoscope, but the complications after their removal are very high. In our patient, one and a half years after placement of SEMS, she developed cough with dyspnoea, video bronchoscopy showed stenosis above the level of stent with granulation tissue inside the stent, stent fracture in lower part and stent migration to right main bronchus, thus she had all conceivable complications of stent placement. The stent was removed with the help of rigid bronchoscope under general anaesthesia. She was discharged the following day. The case is being reported because it was unique in having all the possible complications of stent placement, and rare as we could take out the stent in Toto. Thirdly, the stent could be removed without any complication.

  3. 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.

  4. Percutaneous Ureteral stent insertion

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Yup; Sung, Dong Wook; Choi, Woo Suk; Lee, Dong Ho; Ko, Young Tae; Lee, Sun Wha; Lim, Jae Hoon [Kyung Hee University Hospital, Seoul (Korea, Republic of)

    1990-10-15

    Percutaneous ureteral stent insertion is a treatment of permanent or temporary urinary diversion to maintain continuity and function of the obstructed and injured ureter. We performed 31 cases of percutaneous double pig tall ureteral stent insertion in 21 patients, included 13 patients with malignant ureteral obstruction and eight patients with injured ureter as well as benign inflammatory stricture. Satisfactory resulted was obtained in all patients but one, who need percutaneous nephrostomy on week later for urinary diversion. No significant complication was encountered. The authors concluded that percutaneous ureteral stent insertion, an interventional procedure alternative to urologic retrograde method, is an effective method for urinary diversion.

  5. A Novel Non-Planar Transverse Stretching Process for Micro-Porous PTFE Membranes and Resulting Characteristics

    KAUST Repository

    Chang, Y.-H.; Chen, S.-C.; Wang, T.-J.; Guo, J.

    2018-01-01

    Polytetrafluoroethylene (PTFE) micro-porous membranes were prepared from PTFE fine powder through extruding, rolling, and uniaxial longitudinally stretching. In contrast to conventional planar transverse stretching, a novel 3D mold design of non

  6. Low-Flammability PTFE for High-Oxygen Environments

    Science.gov (United States)

    Walle, E.; Fallon, B.; Sheppard, A.

    1986-01-01

    Modified forming process removes volatile combustible materials. Flammability of cable-wrapping tape reduced by altering tape-manufacturing process. In new manufacturing process, tape formed by proprietary process of screw extrusion, followed by washing in solvent and drying. Tape then wrapped as before. Spectrogram taken after extrusion, washing, and drying shows lower hydrocarbon content. PTFE formed by new process suited to oxygen-rich environments. Safe in liquid oxygen of Space Shuttle tank and in medical uses; thin-wall shrinkable tubing in hospital test equipment, surgical instruments, and implants.

  7. One Year Outcomes of 101 BeGraft Stent Grafts used as Bridging Stents in Fenestrated Endovascular Repairs.

    Science.gov (United States)

    Spear, Rafaelle; Sobocinski, Jonathan; Hertault, Adrien; Delloye, Matthieu; Azzauiu, Richard; Fabre, Dominique; Haulon, Stéphan

    2018-04-01

    To evaluate the outcomes of the second generation BeGraft balloon expandable covered stent Graft System (Bentley InnoMed, Hechingen, Germany) implanted as bridging stent grafts during fenestrated endovascular aortic repair (FEVAR) of complex aneurysms. This was a single centre prospective study including all consecutive patients treated by FEVAR performed with second generation BeGraft stent grafts as bridging stents. Demographics of patients, diameter and length of the bridging stent grafts, technical success, re-interventions, occlusions, post-operative events, and imaging (Cone Beam CT and/or CT scan, and contrast enhanced ultrasound) were prospectively collected in an electronic database. Duplex ultrasound was performed before discharge and at 6 month follow-up. At 1 year, patients were evaluated clinically and by imaging (CT and ultrasound). Between November 2015 and September 2016, 39 consecutive patients (one woman) were treated with custom made fenestrated endografts (2-5 fenestrations) for complex aneurysms or type 1 endoleak after EVAR, using a variety of bridging stents including the BeGraft. All 101 BeGraft stent grafts were successfully delivered and deployed. There was no in hospital mortality. Early fenestration patency rate was 99% (96/97); the sole target vessel post-operative occlusion was secondary to a dissection of the renal artery distal to the stent. Complementary stenting was unsuccessful in recovering renal artery patency; bilateral renal stent occlusion was observed in the same patient on a CT scan performed 2 months after the procedure. He required post-operative dialysis. No additional renal impairment was observed. During follow-up (median 13 months [11-15]), all fenestrations stented with BeGraft stent grafts remained patent (95/97, 98%). One type 1b endoleak was detected and treated (2.6%). BeGraft stent grafts used as bridging stents during FEVAR are associated with favourable outcomes at 1 year follow-up. Long-term follow-up is

  8. Tissue Responses to Stent Grafts with Endo-Exo-Skeleton for Saccular Abdominal Aortic Aneurysms in a Canine Model

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Il Young; Chung, Jin Wook; Kim, Hyo Cheol [Dept. of Radiology and Institute of Radiation Medicine, Seoul National University College of Medicine, Clinical Research Institute, Seoul (Korea, Republic of); Choi, Young Ho; So Young Ho [Dept. of Radiology, Seoul National University Boramae Hospital, Seoul (Korea, Republic of); Kim, Hyun Beom [Dept. of Radiology, National Cancer Center, Goyang (Korea, Republic of); Min, Seung Kee [Dept. of Surgery, Seoul National University College of Medicine, Seoul (Korea, Republic of); Park, Jae Hyung [Dept. of Radiology, Gachon University Gil Medical Center, Incheon (Korea, Republic of)

    2014-10-15

    We evaluated the effect of close contact between the stent and the graft on the induction of endothelial covering on the stent graft placed over an aneurysm. Saccular abdominal aortic aneurysms were made with Dacron patch in eight dogs. The stent graft consisted of an inner stent, a expanded polytetrafluoroethylene graft, and an outer stent. After sacrificing the animals, the aortas with an embedded stent graft were excised. The aortas were inspected grossly and evaluated microscopically. The animals were sacrificed at two (n = 3), six (n = 3), and eight months (n = 2) after endovascular repair. In two dogs, the aortic lumen was occluded at two months after the placement. On gross inspection of specimens from the other six dogs with a patent aortic lumen, stent grafts placed over the normal aortic wall were covered by glossy white neointima, whereas, stent grafts placed over the aneurysmal aortic wall were covered by brownish neointima. On microscopic inspection, stent grafts placed over the normal aortic wall were covered by thin neointima (0.27 ± 0.05 mm, mean ± standard deviation) with an endothelial layer, and stent grafts placed over the aneurysmal aortic wall were covered by thick neointima (0.62 ± 0.17 mm) without any endothelial lining. Transgraft cell migration at the normal aortic wall was more active than that at the aneurysmal aortic wall. Close contact between the stent and the graft, which was achieved with stent grafts with endo-exo-skeleton, could not enhance endothelial covering on the stent graft placed over the aneurysms.

  9. Immobilisation of a fibrillin-1 fragment enhances the biocompatibility of PTFE.

    Science.gov (United States)

    Hajian, Hamid; Wise, Steven G; Bax, Daniel V; Kondyurin, Alexey; Waterhouse, Anna; Dunn, Louise L; Kielty, Cay M; Yu, Young; Weiss, Anthony S; Bilek, Marcela M M; Bannon, Paul G; Ng, Martin K C

    2014-04-01

    Current vascular biomaterials exhibit poor biocompatibility characterised by failure to promote endothelialisation, predisposition to neoinitmal hyperplasia and excessive thrombogenicity. Fibrillin-1, a major constituent of microfibrils is associated with elastic fibres in the arterial wall. Fibrillin-1 binds to endothelial cells through an RGD cell adhesion motif in the fourth TB module. The RGD motif is present in PF8, a recombinant fibrillin-1 fragment. We investigated the potential of PF8 to improve the biocompatibility of PTFE. PF8 enhanced endothelial cell attachment and cell proliferation to a greater extent than fibronectin (pPTFE using plasma immersion ion implantation (PIII), retained these favourable cell interactive properties, again promoting endothelial cell attachment and proliferation. The thrombogenicity of covalently bound PF8 on PTFE was assessed in both static and dynamic conditions. In static conditions, uncoated PIII treated PTFE was more thrombogenic than untreated PTFE, while PF8 coating reduced thrombogenicity. Under flow, there was no difference in the thrombogenicity of PF8 coated PTFE and untreated PTFE. Immobilised PF8 shows a striking ability to promote attachment and growth of endothelial cells on PTFE, while providing a non-thrombogenic surface. These features make PF8 a promising candidate to improve the biocompatibility of current synthetic vascular grafts. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

  10. Sutures for inguinal herniorrhaphy--a comparison of monofilaments with PTFE.

    Science.gov (United States)

    Cahill, J.; Northeast, A. D.; Jarret, P. E.; Leach, R. D.

    1989-01-01

    Polybutester (Novafil, Davis & Geck) and expanded polytetrafluoroethylene PTFE (Gore-tex, W L Gore) were compared with nylon (Ethilon, Ethicon UK) for elective inguinal herniorrhaphy. PTFE had the best handling characteristics, but is expensive, and increased wound sepsis attended its use. Polybutester had significantly better handling characteristics, and is an attractive alternative to nylon for hernia repair. PMID:2705719

  11. Fluoropolymer-coated dacron versus PTFE grafts for femorofemoral crossover bypass: randomised trial

    DEFF Research Database (Denmark)

    Eiberg, JP; Røder, Ole Christian; Stahl-Madsen, M

    2006-01-01

    To investigate whether patency of a thin walled 8 mm fluoropassivated Dacron graft was similar to that of a standard 8mm PTFE graft for femorofemoral crossover bypass surgery.......To investigate whether patency of a thin walled 8 mm fluoropassivated Dacron graft was similar to that of a standard 8mm PTFE graft for femorofemoral crossover bypass surgery....

  12. Preparation of PVDF and PTFE membranes for fuel cell use; Preparacao de membranas de PVDF e PTFE enxertadas e sulfonadas para uso em celula a combustivel

    Energy Technology Data Exchange (ETDEWEB)

    Geraldes, Adriana N.; Zen, Heloisa A.; Ferreira, Henrique P.; Parra, Duclerc F.; Lugao, Ademar B.; Linardi, Marcelo [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], e-mail: angeral@ipen.br

    2007-07-01

    Grafting of styrene onto polyvinylidenefluoride (PVDF), polytetrafluoroethylene (PTFE) was studied using styrene/toluene solutions. First, PTFE and PVDF films were prepared and the process was conducted by radiation induced graft polymerization of styrene, by a Co{sup 60} source. Films of PTFE and PVDF were immersed in styrene/toluene at 1:1 (v/v) concentration and then submitted to gamma radiation at 20 kGy doses. After irradiation, the samples were evaluated at the period of 21 days at room temperature in order to observe the grafting degree. Chemical changes in the PVDF and PTFE films after styrene grafting were monitored and the results were evaluated by FTIR, DSC, TGA and degree of grafting (DOG). The ion exchange capacity (IEC) after sulfonation of 1, 2 and 24 hours were also determined. (author)

  13. 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....

  14. Comparison of TEVAR resin beads, PAN fibers, and ePTFE membranes as a solid support for Aliquat-336 in immobilized liquid extraction chromatography for separation of actinides

    International Nuclear Information System (INIS)

    Joe Dauner; Steve Workman

    2012-01-01

    The following paper covers a comparison of two new systems to traditional TEVA R resin systems for the analytical separation of actinides by immobilized liquid-liquid extraction using Aliquat-336. The new systems are using expanded polytetrafluroethane (ePTFE) membrane or polyacrylonitrile (PAN) fibers as the solid support. The systems are compared in two ways. First in how much Aliquat-336 they contain with the Vs, ratio of volume of Aliquat-336 to volume of polymeric support, being 0.158, 0.483, and 0.590 for the TEVA R resin, PAN fibers, and the ePTFE systems, respectively. The second comparison is in their performance capacity of extraction of uranyl chloride anion complex. The fiber and resins systems show similar capacities, and the membrane system being an order of magnitude less than the other systems. A cost comparison demonstrates the savings advantages of using a fiber based support compared with resin and membrane support systems. (author)

  15. Effect of longitudinal anatomical mismatch of stenting on the mechanical environment in human carotid artery with atherosclerotic plaques.

    Science.gov (United States)

    Fan, Zhenmin; Liu, Xiao; Sun, Anqiang; Zhang, Nan; Fan, Zhanming; Fan, Yubo; Deng, Xiaoyan

    2017-10-01

    Longitudinal anatomic mismatch (LAM) of stenting (i.e., a stenotic artery segment is not fully covered by a deployed stent) worsens the mechanical environment in the treated artery, which most likely is the cause for the associated high risks of restenosis, myocardial infarction and stent thrombosis. To probe the possibility, we constructed a patient-specific carotid model with two components of plaques (lipid and calcified plaque) based on MRI images; we numerically compared three different stenting scenarios in terms of von Mises stress (VMS) distribution in the treated arteries, namely, the short stenting (LAM), the medium stenting and the long stenting. The results showed that the short stenting led to more areas with abnormally high VMS along the inner surface of the treated artery with a much higher surface-averaged VMS at the distal end of the stent than both the medium and long stenting. While the VMS distribution in the calcified plaques was similar for the three stenting models, it was quite different in the lipid plaques among the three stenting models. The lipid plaque of the short-stent model showed more volume of the lipid plaque subjected to high VMS than those of the other two models. Based on the obtained results, we may infer that the short stenting (i.e., LAM) may aggravate vascular injury due to high VMS on the artery-stent interaction surface and within the lipid plaque. Therefore, to obtain a better outcome, a longer stent, rather than a short one, might be needed for arterial stenting. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

  16. 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.

  17. 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.

  18. Surface modification and adhesion improvement of PTFE film by ion beam irradiation

    International Nuclear Information System (INIS)

    Lee, S.W.; Hong, J.W.; Wye, M.Y.; Kim, J.H.; Kang, H.J.; Lee, Y.S.

    2004-01-01

    The polytetrafluoroethylene (PTFE) surfaces, modified by 1 kV Ar + or O 2 + ion beam irradiation, was investigated with in-situ X-ray photoelectron spectroscopy (XPS), scanning electron micrographs (SEM), atomic force microscopy (AFM) measurements. The surface of PTFE films modified by Ar + ion irradiation was carbonized and the surface roughness increased with increasing ion doses. The surface of PTFE films modified by both Ar + ion in O 2 atmosphere and O 2 + ion irradiation formed the oxygen function group on PTFE surface, and the surface roughness change was relatively small. The adhesion improvement in Ar + ion irradiated PTFE surface is attributed to mechanical interlocking due to the surface roughness and -CF-radical, but that in Ar + ion irradiation in an O 2 atmosphere was contributed by the C-O complex and -CF-radical with mechanical interlocking. The C-O complex and -CF-radical in O 2 + ion irradiated surface contributed to the adhesion

  19. Fabrication and Characteristics of Al/PTFE Multilayers and Application in Micro-initiator

    Science.gov (United States)

    Zhang, Yuxin; Jiang, Hongchuan; Zhao, Xiaohui; Zhang, Wanli; Li, Yanrong

    2017-12-01

    In this paper, a micro-initiator was designed and fabricated by integrating Al/PTFE multilayers with a Cu film bridge. The regularity layer structure and interface composition of Al/PTFE multilayers was analysed by transmission electron microscope and X-ray photoelectron spectroscopy, respectively. The heat release reaction in Al/PTFE multilayers can be triggered with reaction temperature of 430 °C, and the overall heat of reaction is 3192 J/g. Al/PTFE multilayers with bilayer thickness of 200 nm was alternately deposited on a Cu film bridge to improve the electric explosion performances. Compared to Cu film bridge, the Al/PTFE/Cu integrated film bridge exhibits improved performances with longer explosion duration time, more violent explosion phenomenon and larger quantities of ejected product particles.

  20. Radiation-induced branching and crosslinking of poly(tetrafluoroethylene) (PTFE)

    International Nuclear Information System (INIS)

    Lappan, U.; Geissler, U.; Haeussler, L.; Jehnichen, D.; Pompe, G.; Lunkwitz, K.

    2001-01-01

    The effect of electron beams on poly(tetrafluoroethylene) (PTFE) at elevated temperatures above the melting point on oxygen-free conditions has been studied using differential scanning calorimetry (DSC), wide-angle X-ray scattering (WAXS), Fourier-transform infrared (FTIR) spectroscopy, thermo-gravimetric analysis (TGA) and tensile test. The investigations have shown that the chemical structure and several properties of PTFE are greatly altered by the irradiation. DSC and WAXS indicate that the crystallinity of the PTFE irradiated with high doses is reduced. CF 3 side groups and branched structures are assumed to hinder the crystallization. TGA has shown that the thermal stability of the radiation-modified PTFE is considerably lower than that of unirradiated PTFE

  1. Renal vessel reconstruction in kidney transplantation using a polytetrafluoroethylene (PTFE) vascular graft.

    Science.gov (United States)

    Kamel, Mohamed H; Thomas, Anil A; Mohan, Ponnusamy; Hickey, David P

    2007-04-01

    We report a rare experience in reconstructing short renal vessels in kidney transplantation using polytetrafluroethylene (PTFE) vascular grafts. The short renal vessels in three kidney grafts were managed by the interposition of PTFE vascular grafts. Two grafts were from deceased donors and the third was a renal auto-transplant graft. PTFE grafts were used to lengthen short renal veins in two kidney grafts and a short renal artery in one. The warm ischaemia time was under 1 h and all kidneys functioned well post-operatively. Excellent blood perfusion in the three renal grafts was present on postoperative MAG 3 renal scan. No intra-operative or post-operative complications were encountered. In the three described patients, the use of PTFE vascular graft presented no additional morbidity to the kidney transplant operation and no post-oerative complication was related to its use. However, more data are necessary to conclude that PTFE graft can be used safely in kidney transplantation.

  2. Improvement of radiation resistance for polytetrafluoroethylene(PTFE) by radiation cross-linking

    International Nuclear Information System (INIS)

    Oshima, Akihiro; Tabata, Yoneho; Ikeda, Shigetoshi; Seguchi, Tadao.

    1996-01-01

    The crosslinked polytetrafluoroethylene(PTFE) was prepared by electron beams irradiation technique in the molten state at 340degC ± 3degC in inert gas atmosphere. The crosslinking density was changed by the irradiation dose. The radiation resistance of crosslinked PTFE was investigated on the mechanical properties after irradiation by γ-rays at room temperature under vacuum and in air. The dose at half value of elongation at break was about 1MGy for 500kGy-crosslinked PTFE, while the dose for non-crosslinked PTFE was only 3.5kGy. It was found that the radiation resistance of PTFE was extremely improved by crosslinking. (author)

  3. Thermally stimulated current in PTFE and its application in radiation dosimetry

    International Nuclear Information System (INIS)

    Ozdemir, S.

    1985-01-01

    Thermally Stimulated Current (TSC) measurement was made on PTFE (Polytetrafluoro ethylene) in an attempt to develop an integrating radiation dosimeter material and the system. TSC spectra, dose response, energy response, fading and background charge stability characteristics were used as a measure of suitability of various untreated and heat treated PTFE samples for dosimetry applications. For practical TSC dosimetry system, it was discovered that the PTFE samples should be subjected to a specific heat treatment in order to produce samples with better dosimeter characteristics. A treatment at a temperature of 240 C produces a high dose response and low fading characteristics. It was found that the spurious charges due to storage and low sensitivity to irradiation caused the limitation in the measurement of low doses with PTFE samples for personnel protection. However, a TSC Dosimetry system using PTFE is proposed which is suitable for radiation doses in the radiotherapy range from *approx* 50 to *approx* 800 mGy. (author)

  4. Effect of gamma radiation on graphite – PTFE dry lubrication system

    International Nuclear Information System (INIS)

    Singh, Sachin; Tyagi, Mukti; Seshadri, Geetha; Tyagi, Ajay Kumar; Varshney, Lalit

    2017-01-01

    An effect of gamma radiation on lubrication behavior of graphite -PTFE dry lubrication system has been studied using (TR-TW-30L) tribometer with thrust washer attachment in plane contact. Different compositions of graphite and PTFE were prepared and irradiated by gamma rays. Gamma radiation exposure significantly improves the tribological properties indicated by decrease in coefficient of friction and wear properties of graphite -PTFE dry lubrication system. SEM and XRD analysis confirm the physico-chemical modification of graphite-PTFE on gamma radiation exposure leading to a novel dry lubrication system with good slip and anti friction properties. - Highlights: • Novel dry lubrication system of graphite -PTFE using gamma radiation. • Gamma radiation processing. • Reduction in coefficient of friction, frictional torque and wear loss of developed dry lubrication system.

  5. 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.

  6. Electrophoretic deposition of PTFE particles on porous anodic aluminum oxide film and its tribological properties

    International Nuclear Information System (INIS)

    Zhang, Dongya; Dong, Guangneng; Chen, Yinjuan; Zeng, Qunfeng

    2014-01-01

    Polytetrafluoroethylene (PTFE) composite film was successfully fabricated by depositing PTFE particles into porous anodic aluminum oxide film using electrophoretic deposition (EPD) process. Firstly, porous anodic aluminum oxide film was synthesized by anodic oxidation process in sulphuric acid electrolyte. Then, PTFE particles in suspension were directionally deposited into the porous substrate. Finally, a heat treatment at 300 °C for 1 h was utilized to enhance PTFE particles adhesion to the substrate. The influence of anodic oxidation parameters on the morphology and micro-hardness of the porous anodic aluminum oxide film was studied and the PTFE particles deposited into the pores were authenticated using energy-dispersive spectrometer (EDS) and scanning electron microscopy (SEM). Tribological properties of the PTFE composite film were investigated under dry sliding. The experimental results showed that the composite film exhibit remarkable low friction. The composite film had friction coefficient of 0.20 which deposited in 15% PTFE emulsion at temperature of 15 °C and current density of 3 A/dm 2 for 35 min. In addition, a control specimen of porous anodic aluminum oxide film and the PTFE composite film were carried out under the same test condition, friction coefficient of the PTFE composite film was reduced by 60% comparing with the control specimen at 380 MPa and 100 mm/s. The lubricating mechanism was that PTFE particles embedded in porous anodic aluminum oxide film smeared a transfer film on the sliding path and the micro-pores could support the supplement of solid lubricant during the sliding, which prolonged the lubrication life of the aluminum alloys.

  7. Repair of large abdominal wall defects with expanded polytetrafluoroethylene (PTFE).

    Science.gov (United States)

    Bauer, J J; Salky, B A; Gelernt, I M; Kreel, I

    1987-01-01

    Most abdominal wall incisional hernias can be repaired by primary closure. However, where the defect is large or there is tension on the closure, the use of a prosthetic material is indicated. Expanded polytetrafluoroethylene (PTFE) patches were used to repair incisional hernias in 28 patients between November 1983 and December 1986. Twelve of these patients (43%) had a prior failure of a primary repair. Reherniation occurred in three patients (10.7%). Wound infections developed in two patients (7.1%), both of whom had existing intestinal stomas, one with an intercurrent pelvic abscess. The prosthetic patch was removed in the patient with the abscess, but the infection was resolved in the other without sequelae. Septic complications did not occur after any operations performed in uncontaminated fields. None of the patients exhibited any undue discomfort, wound pain, erythema, or induration. Complications related to adhesions, erosion of the patch material into the viscera, bowel obstruction, or fistula formation did not occur. Based on this clinical experience, the authors believe that the PTFE patch appears to represent an advance in synthetic abdominal wall substitutes. Images Fig. 1. Fig. 2(left)., Fig. 3(right). PMID:3689012

  8. Drug eluting stents and modern stent technologies for in-stent restenosis.

    Science.gov (United States)

    Werner, Martin

    2017-08-01

    The implantation of metallic stents has become a standard procedure to improve the outcome after angioplasty of peripheral vessels. However, the occurrence of in-stent restenosis is hampering the long-term efficacy of these procedures and is associated with re-occurrence of symptoms. The optimal treatment modality for in-stent-restenosis in the peripheral vasculature is not well examined. This review discusses the existing evidence for the treatment of in-stent restenosis with drug eluting stents and modern stent technologies.

  9. The risk and prognostic impact of definite stent thrombosis or in-stent restenosis after coronary stent implantation

    DEFF Research Database (Denmark)

    Thayssen, Per; Jensen, Lisette Okkels; Lassen, Jens Flensted

    2012-01-01

    Aims: Data are limited on the prognostic impact of stent thrombosis and in-stent restenosis in patients treated with coronary stents. We examined the prognostic impact of stent thrombosis and in-stent restenosis in patients treated with percutaneous coronary intervention (PCI). Methods and results......: All patients who underwent stent implantation from 2002 to 2005 were identified in the Western Denmark Heart Registry. The hazard ratio (HR) for death associated with stent thrombosis or in-stent restenosis was estimated with a Cox regression analysis with stent thrombosis or in-stent restenosis...... as time-dependent variables. A total of 12,277 patients were treated with stent implantation. Stent thrombosis was observed in 111 (0.9%) patients and in-stent restenosis in 503 (4.1%) patients within 12 months after the index PCI. Occurrence of stent thrombosis was associated with an increased risk...

  10. 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

  11. Mechanical Stability of H3PO4-Doped PBI/Hydrophilic-Pretreated PTFE Membranes for High Temperature PEMFCs

    International Nuclear Information System (INIS)

    Park, Jaehyung; Wang, Liang; Advani, Suresh G.; Prasad, Ajay K.

    2014-01-01

    Graphical abstract: - Highlights: • PBI/PTFE membrane was prepared by porous PTFE with hydrophilic surface pretreatment. • The durability of the prepared PBI/PTFE membrane was compared with pure PBI, PBI with untreated PTFE, and PBI-Nafion with untreated PTFE membranes. • Accelerated durability tests and SEM showed improved durability based the PBI/PTFE membrane with pretreated PTFE. - Abstract: A novel polybenzimidazole (PBI)/poly(tetrafluoroethylene) (PTFE) composite membrane doped with phosphoric acid was fabricated for high temperature operation in a polymer electrolyte membrane (PEM) fuel cell. A hydrophilic surface pretreatment was applied to the porous PTFE matrix film to improve its interfacial adhesion to the PBI polymer, thereby avoiding the introduction of Nafion ionomer which is traditionally used as a coupling agent. The pretreated PTFE film was embedded within the composite membrane during solution-casting using 5wt% PBI/DMAc solution. The mechanical stability and durability of three types of MEAs assembled with PBI only, PBI with pretreated PTFE, and PBI-Nafion with untreated PTFE membranes were evaluated under an accelerated degradation testing protocol employing extreme temperature cycling. Degradation was characterized by recording polarization curves, hydrogen crossover, and proton resistance. Cross-sections of the membranes were examined before and after thermal cycling by scanning electron microscope. Energy-dispersive X-ray spectroscopy verified that the PBI is dispersed homogeneously in the porous PTFE matrix. Results show that the PBI composite membrane with pretreated PTFE has a lower degradation rate than the Nafion/PBI membrane with untreated PTFE. Thus, the hydrophilic pretreatment employed here greatly improved the mechanical stability of the composite membrane, which resulted in improved durability under an extreme thermal cycling regime

  12. Impacted calculus within a urethral stent: A rare cause of urinary retention

    Directory of Open Access Journals (Sweden)

    Shanmugasundaram Rajaian

    2011-01-01

    Full Text Available An elderly male presented to the emergency department with acute urinary retention. He had poor flow of urine associated with serosanguinous discharge per urethra for 3 days duration. Earlier he underwent permanent metallic urethral stenting for post TURP bulbar urethral stricture. Plain X-ray of Pelvis showed an impacted calculus within the urethral stent in bulbar urethra. Urethrolitholapaxy was done with semirigid ureteroscope. Urethral stent was patent and well covered. Subsequently he had an uneventful recovery. We describe a unique case of acute urinary retention due to calculus impaction within a urethral stent.

  13. Biodegradable airway stents in infants - Potential life-threatening pitfalls.

    Science.gov (United States)

    Sztanó, B; Kiss, G; Márai, K; Rácz, G; Szegesdi, I; Rácz, K; Katona, G; Rovó, L

    2016-12-01

    The solution of severe tracheobronchial obstructions in early childhood means a great challenge. Biodegradable stents were intended to be a minimally invasive temporary solution which may decrease the number of interventions and limit the possible complications of stenting procedures. However, our first experiences have brought out a new, - especially in childhood - potentially life-threatening complication of this concept. Five SX-ELLA biodegradable polydioxanone stents was applied in three patients because of severe tracheobronchial obstruction: congenital tracheomalacia (7 day-old), acquired tracheomalacia (10 month-old), and congenital trachea-bronchomalacia (10 month-old). The breathing of all children improved right after the procedure. We observed degradation of the stent from the 5th postoperative week which resulted in large intraluminar fragments causing significant airway obstruction: one patient died of severe pneumonia, the other baby required urgent bronchoscopy to remove the obstructing 'foreign body' from the trachea. In the third case repeated stent placements successfully maintained the tracheal lumen. Polydioxanone stents may offer an alternative to metallic or silastic stents for collapse or external compression of the trachea in children; however, large decaying fragments mean a potential risk especially in the small size pediatric airway. The fragmentation of the stent, which generally starts in the 4-6 postoperative weeks, may create large sharp pieces. These may be anchored to the mucosa and covered by crust leading to obstruction. As repeated interventions are required, we do not consider the application of biodegradable stents unambiguously advantageous. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  14. 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

  15. Transluminal endovascular stent-graft for the treatment of aortic aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Do Yun; Chang, Byung Chul; Shim, Won Heum; Cho, Seung Yun; Chung, Nam Sik; Kwon, Hyuk Moon; Lee, Young Joon; Lee, Jong Tae [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    1995-09-15

    The standard treatment for aortic aneurysms is surgical replacement with a prosthetic graft. Currently there is great interest in endoluminal intervention for treatment of aortic aneurysm. The purpose of this study was to evaluate the safety and effectiveness of endoluminally placed Stent-graft for the treatment of aortic aneurysms. Transluminal endovascular Stent-graft placements were attempted in 9 patients with infra-renal aortic aneurysms(n 6), thoracic aortic aneurysm(n = 1), and aortic dissection(n = 2). The endovascular Stent-grafts were custom-designed for each patient and were constructed of self-expandable modified Gianturco Stents covered with polytetrafluroethylene. The Stent-grafts were introduced through a 16-18 French sheath and expanded to 17-30 mm in diameter. The endovascular therapy was performed using a common femoral artery cutdown with local anesthesia. The endovascular Stent-graft deployment was achieved in 7 of 9 patients. Two cases failed deployment of the Stent-graft due to iliac artery stenosis and tortousity. There were complete thrombosis of the thoracic and infra-renal aortic aneurysm surround the Stent-graft in 3 patients, and persistent leak with partial thrombosis in 2. Two patients with aortic dissection were successfully treated by obliteration of entry tears. There were no major complication associated with Stent-graft placement. These preliminary results show that transluminal endovascular Stent-grafts offer great promise and good results. Further investigation is needed to establish its long-term safety and efficacy.

  16. 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.

  17. Transluminal endovascular stent-graft for the treatment of aortic aneurysms

    International Nuclear Information System (INIS)

    Lee, Do Yun; Chang, Byung Chul; Shim, Won Heum; Cho, Seung Yun; Chung, Nam Sik; Kwon, Hyuk Moon; Lee, Young Joon; Lee, Jong Tae

    1995-01-01

    The standard treatment for aortic aneurysms is surgical replacement with a prosthetic graft. Currently there is great interest in endoluminal intervention for treatment of aortic aneurysm. The purpose of this study was to evaluate the safety and effectiveness of endoluminally placed Stent-graft for the treatment of aortic aneurysms. Transluminal endovascular Stent-graft placements were attempted in 9 patients with infra-renal aortic aneurysms(n 6), thoracic aortic aneurysm(n = 1), and aortic dissection(n = 2). The endovascular Stent-grafts were custom-designed for each patient and were constructed of self-expandable modified Gianturco Stents covered with polytetrafluroethylene. The Stent-grafts were introduced through a 16-18 French sheath and expanded to 17-30 mm in diameter. The endovascular therapy was performed using a common femoral artery cutdown with local anesthesia. The endovascular Stent-graft deployment was achieved in 7 of 9 patients. Two cases failed deployment of the Stent-graft due to iliac artery stenosis and tortousity. There were complete thrombosis of the thoracic and infra-renal aortic aneurysm surround the Stent-graft in 3 patients, and persistent leak with partial thrombosis in 2. Two patients with aortic dissection were successfully treated by obliteration of entry tears. There were no major complication associated with Stent-graft placement. These preliminary results show that transluminal endovascular Stent-grafts offer great promise and good results. Further investigation is needed to establish its long-term safety and efficacy

  18. Preparation and Properties of PTFE-PMMA Core-Shell Nanoparticles and Nanocomposites

    Directory of Open Access Journals (Sweden)

    Diego Antonioli

    2012-01-01

    Full Text Available The preparation of polytetrafluoroethylene-poly(methyl methacrylate (PTFE-PMMA core-shell particles was described, featuring controlled size and narrow size distribution over a wide compositional range, through a seeded emulsion polymerization starting from a PTFE seed of 26 nanometers. Over the entire MMA/PTFE range, the particle size increases as the MMA/PTFE ratio increases. A very precise control over the particle size can be exerted by properly adjusting the ratio between the monomer and the PTFE seed. Particles in the 80–240 nm range can be prepared with uniformity indexes suited to build 2D and 3D colloidal crystals. These core-shell particles were employed to prepare nanocomposites with different compositions, through an annealing procedure at a temperature higher than the glass transition temperature of the shell forming polymer. A perfect dispersion of the PTFE particles within the PMMA matrix was obtained and optically transparent nanocomposites were prepared containing a very high PTFE amount.

  19. MgTiO3 filled PTFE composites for microwave substrate applications

    International Nuclear Information System (INIS)

    Yuan, Y.; Zhang, S.R.; Zhou, X.H.; Li, E.Z.

    2013-01-01

    MgTiO 3 filled PTFE composite substrates were fabricated for microwave circuit applications. The filler content in the PTFE matrix was varied from 30 to 70 wt%. Low loss MgTiO 3 ceramic powder was prepared by the solid state ceramic route. The phase formation of MgTiO 3 was studied by powder X-ray diffraction analysis. Morphology of the composites and dispersion of filler in the PTFE matrix was studied using scanning electron microscopy. Microwave dielectric properties of the composites with respect to filler loading were measured by stripline resonator method using Vector Network Analyzer. Different theoretical modeling approaches were used to predict the dielectric constant of PTFE ceramic composites with respect to filler loading. The linear coefficient of thermal expansion of the composites was investigated. Moisture absorption of the composites was found out conforming to IPC-TM-650 2.6.2. - Highlights: • We prepare MT/PTFE composite by cold pressing and hot treating. • Increasing MT will increase ε r , tan δ and moisture absorption. • Increasing MT will decrease thermal expansion coefficient. • MT/PTFE composite has an ε r of 4.3 and a tan δ of 0.00097 at 50 wt% filler loading. • MT/PTFE composite are promising candidates for microwave circuit applications

  20. XPS analysis of the effect of fillers on PTFE transfer film development in sliding contacts

    Science.gov (United States)

    Blanchet, T. A.; Kennedy, F. E.; Jayne, D. T.

    1993-01-01

    The development of transfer films atop steel counterfaces in contact with unfilled and bronze-filled PTFE has been studied using X-ray photoelectron spectroscopy. The sliding apparatus was contained within the vacuum of the analytical system, so the effects of the native oxide, hydrocarbon, and adsorbed gaseous surface layers of the steel upon the PTFE transfer behavior could be studied in situ. For both the filled and the unfilled PTFE, cleaner surfaces promoted greater amounts of transfer. Metal fluorides, which formed at the transfer film/counterface interface, were found solely in cases where the native oxide had been removed to expose the metallic surface prior to sliding. These fluorides also were found at clean metal/PTFE interfaces formed in the absence of frictional contact. A fraction of these fluorides resulted from irradiation damage inherent in XPS analysis. PTFE transfer films were found to build up with repeated sliding passes, by a process in which strands of transfer filled in the remaining counterface area. Under these reported test conditions, the transfer process is not expected to continue atop previously deposited transfer films. The bronze-filled composite generated greater amounts of transfer than the unfilled PTFE. The results are discussed relative to the observed increase in wear resistance imparted to PTFE by a broad range of inorganic fillers.

  1. Heterogeneous Intravascular Ultrasound Findings of Stent Thrombosis

    OpenAIRE

    Morofuji, Toru; Inaba, Shinji; Aisu, Hiroe; Takahashi, Kayo; Saito, Makoto; Higashi, Haruhiko; Yoshii, Toyofumi; Sumimoto, Takumi

    2017-01-01

    Objective The underlying mechanisms of stent thrombosis are not completely understood. Methods We experienced 12 definite stent thrombosis cases (1 early, 1 late, and 10 very late) at our hospital from July 2011 to April 2016 and evaluated the possible causes of stent thrombosis by intravascular ultrasound (IVUS). Results Five different potential morphological causes of stent thrombosis (neoatherosclerosis, stent malapposition, stent fracture, edge dissection, and stent underexpansion) were d...

  2. Pulse electrodeposition of self-lubricating Ni–W/PTFE nanocomposite coatings on mild steel surface

    Energy Technology Data Exchange (ETDEWEB)

    Sangeetha, S. [Advanced Nanocomposite Coatings Laboratory, Department of Industrial Chemistry, Alagappa University, Karaikudi 630 003 (India); Kalaignan, G. Paruthimal, E-mail: pkalaignan@yahoo.com [Advanced Nanocomposite Coatings Laboratory, Department of Industrial Chemistry, Alagappa University, Karaikudi 630 003 (India); Anthuvan, J. Tennis [M. Kumarasamy College of Engineering, Karur, Tamil Nadu (India)

    2015-12-30

    Graphical abstract: - Highlights: • PTFE polymer inclusion on Ni–W alloy matrix was electrodeposited by pulse current method. • Tribological properties and electrochemical characterizations of the nanocomposite coatings were analyzed. • The hydrophobic behaviour of Ni–W/PTFE nanocomposite coating was measured. • Ni–W/PTFE nanocomposite coatings have showed superior tribological properties and corrosion resistance relative to that of the Ni–W alloy matrix. - Abstract: Ni–W/PTFE nanocomposite coatings with various contents of PTFE (polytetafluoroethylene) particles were prepared by pulse current (PC) electrodeposition from the Ni–W plating bath containing self lubricant PTFE particles to be co-deposited. Co-deposited PTFE particulates were uniformly distributed in the Ni–W alloy matrix. The coatings were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDAX), X-ray Diffractometry (XRD) and Vicker's micro hardness tester. Tafel Polarization and electrochemical Impedance methods were used to evaluate the corrosion resistance behaviour of the nanocomposite coatings in 3.5% NaCl solution. It was found that, the Ni–W/PTFE nanocomposite coating has better corrosion resistance than the Ni–W alloy coating. Surface roughness and friction coefficient of the coated samples were assessed by Mitutoyo Surftest SJ-310 (ISO1997) and Scratch tester TR-101-M4 respectively. The contact angle (CA) of a water droplet on the surface of nanocomposite coating was measured by Optical Contact Goniometry (OCA 35). These results indicated that, the addition of PTFE in the Ni–W alloy matrix has resulted moderate microhardness, smooth surface, less friction coefficient, excellent water repellency and enhanced corrosion resistance of the nanocomposite coatings.

  3. On compression and damage evolution in PTFE and PEEK

    Science.gov (United States)

    Rau, C.; Parry, S.; Garcea, S. C.; Bourne, N. K.; McDonald, S. A.; Eastwood, D. S.; Brown, E. N.; Withers, P. J.

    2017-01-01

    The well-known Taylor cylinder impact test, that follows the impact of a flat-ended cylindrical rod onto a rigid stationary anvil, is conducted over a range of impact speeds for two polymers, PTFE and PEEK. In previous work experiments and a model were developed to capture the deformation behaviour of the rod after impact. A distinctive feature of these works was that a region in which both spatial and temporal variation of both longitudinal and radial deformation showed evidence of changes in phase within the material. This region is X-ray imaged in a range of impacted targets at the I13 Imaging and Coherence beam line at the Diamond synchrotron. Further techniques were fielded to resolve compressed regions within the recovered polymer cylinders that showed a fracture zone in the impact region. This shows the transit of damage from ductile to brittle failure results from previously undetected internal failure.

  4. Radiation-induced crosslinking of short Fiber-filled polytetrafluoroethylene (PTFE)

    International Nuclear Information System (INIS)

    Oshima, Akihiro; Udagawa, Akira; Morita, Yousuke

    1999-02-01

    The radiation-induced crosslinking of PTFE mixed with short fibers as glass or carbon fibers was studied for processing the composite materials. The crosslinking behaviors did not change by mixing of the fiber under the irradiation condition in oxygen-free atmosphere at temperature at temperature of 330degC - 350degC. The effect of reinforcement by the fibers in the fabricated composite materials was supposed to be a morphological change of PTFE because and adhesion between PTFE and the fibers was hardly observed in the composite materials. (author)

  5. Airborne nanoparticle concentrations in the manufacturing of polytetrafluoroethylene (PTFE) apparel.

    Science.gov (United States)

    Vosburgh, Donna J H; Boysen, Dane A; Oleson, Jacob J; Peters, Thomas M

    2011-03-01

    One form of waterproof, breathable apparel is manufactured from polytetrafluoroethylene (PTFE) membrane laminated fabric using a specific process to seal seams that have been sewn with traditional techniques. The sealing process involves applying waterproof tape to the seam by feeding the seam through two rollers while applying hot air (600 °C). This study addressed the potential for exposure to particulate matter from this sealing process by characterizing airborne particles in a facility that produces more than 1000 lightweight PTFE rain jackets per day. Aerosol concentrations throughout the facility were mapped, breathing zone concentrations were measured, and hoods used to ventilate the seam sealing operation were evaluated. The geometric mean (GM) particle number concentrations were substantially greater in the sewing and sealing areas (67,000 and 188,000 particles cm⁻³)) compared with that measured in the office area (12,100 particles cm⁻³). Respirable mass concentrations were negligible throughout the facility (GM = 0.002 mg m⁻³) in the sewing and sealing areas). The particles exiting the final discharge of the facility's ventilation system were dominated by nanoparticles (number median diameter = 25 nm; geometric standard deviation of 1.39). The breathing zone particle number concentrations of the workers who sealed the sewn seams were highly variable and significantly greater when sealing seams than when conducting other tasks (p < 0.0001). The sealing workers' breathing zone concentrations ranged from 147,000 particles cm⁻³ to 798,000 particles cm⁻³, and their seam responsibility significantly influenced their breathing zone concentrations (p = 0.03). The finding that particle number concentrations were approximately equal outside the hood and inside the local exhaust duct indicated poor effectiveness of the canopy hoods used to ventilate sealing operations.

  6. 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

  7. Endoluminal stenting for the management of leak following sleeve gastrectomy and loop duodenojejunal bypass with sleeve gastrectomy.

    Science.gov (United States)

    Tsai, Ying-Nan; Wang, Hsiu-Po; Huang, Chih-Kun; Chang, Po-Chin; Lin, I-Chang; Tai, Chi-Ming

    2018-01-01

    Postoperative leak is a serious complication of bariatric surgery and often results in significant morbidity and mortality. Stent placement is a less invasive alternative to surgery for the treatment of bariatric surgical leak. We evaluated the efficacy and complications of covered self-expandable metal stents (SEMS) in the treatment of post-bariatric surgical leak. We retrospectively reviewed patients who underwent stent placement for leak after bariatric surgery. Leak was diagnosed by upper gastrointestinal series or was visualized during the endoscopy. We examined the timing of stent placement, size of the leak, stent migration and its complications, total stent treatment duration, and treatment outcome. Between January 2011 and April 2015, seven patients underwent covered SEMS placement for leak after bariatric surgery, including laparoscopic sleeve gastrectomy (LSG) (n = 5) and laparoscopic loop duodenojejunal bypass with sleeve gastrectomy (LDJB-SG) (n = 2). A stent was placed in one patient for infection control and bridging to revisional surgery. Among the other six patients, one patient who received stent placement one year after leak diagnosis failed to achieve leak closure, and five patients with early stent placement achieved leak closure. Three patients with small leak achieved leak closure more quickly. Stent migration was found in six patients, and associated ulcers occurred in five patients. We conclude that stenting is effective in the management of staple-line leaks following LSG and LDJB-SG. Stent migration and associated ulcers are common after stent placement. Early stent removal can be achieved in patients with small leaks. Copyright © 2017. Published by Elsevier Taiwan.

  8. Endoluminal stenting for the management of leak following sleeve gastrectomy and loop duodenojejunal bypass with sleeve gastrectomy

    Directory of Open Access Journals (Sweden)

    Ying-Nan Tsai

    2018-01-01

    Full Text Available Postoperative leak is a serious complication of bariatric surgery and often results in significant morbidity and mortality. Stent placement is a less invasive alternative to surgery for the treatment of bariatric surgical leak. We evaluated the efficacy and complications of covered self-expandable metal stents (SEMS in the treatment of post-bariatric surgical leak. We retrospectively reviewed patients who underwent stent placement for leak after bariatric surgery. Leak was diagnosed by upper gastrointestinal series or was visualized during the endoscopy. We examined the timing of stent placement, size of the leak, stent migration and its complications, total stent treatment duration, and treatment outcome. Between January 2011 and April 2015, seven patients underwent covered SEMS placement for leak after bariatric surgery, including laparoscopic sleeve gastrectomy (LSG (n = 5 and laparoscopic loop duodenojejunal bypass with sleeve gastrectomy (LDJB-SG (n = 2. A stent was placed in one patient for infection control and bridging to revisional surgery. Among the other six patients, one patient who received stent placement one year after leak diagnosis failed to achieve leak closure, and five patients with early stent placement achieved leak closure. Three patients with small leak achieved leak closure more quickly. Stent migration was found in six patients, and associated ulcers occurred in five patients. We conclude that stenting is effective in the management of staple-line leaks following LSG and LDJB-SG. Stent migration and associated ulcers are common after stent placement. Early stent removal can be achieved in patients with small leaks.

  9. Non-Cyanide Electrodeposited Ag–PTFE Composite Coating Using Direct or Pulsed Current Deposition

    Directory of Open Access Journals (Sweden)

    Raymond Sieh

    2016-07-01

    Full Text Available The effects of FC-4 cationic surfactant on electrodeposited Ag–PTFE composite coating using direct or pulsed currents were studied using scanning electron microscope (SEM, energy dispersive X-ray (EDS, optical microscope, and a linear tribometer. FC-4:PTFE in various ratios were added to a non-cyanide succinimide silver complex bath. Direct or pulsed current method was used at a constant current density to enable comparison between both methods. A high incorporation rate of PTFE was successfully achieved, with pulsed current being highly useful in increasing the amount of PTFE in the composite coating. The study of coating wear under sliding showed that a large majority of the electrodeposited coatings still managed to adhere to the substrate, even after 10 wear cycles of sliding tests. Performance improvements were achieved on all the samples with a coefficient of friction (CoF between 0.06 and 0.12.

  10. Less Than Total Excision of Infected Prosthetic PTFE Graft Does Not Increase the Risk of Reinfection.

    Science.gov (United States)

    Sgroi, Michael D; Kirkpatrick, Vincent E; Resnick, Karen A; Williams, Russell A; Wilson, Samuel E; Gordon, Ian L

    2015-01-01

    Traditional treatment of infected polytetrafluoroethylene (PTFE) grafts consist of removal of the entire prosthesis. Closure of the native vessels may compromise vascular patency. We examined the outcomes for patients in whom a PTFE remnant of an infected graft was retained on the vessel. We reviewed the operating room log from 2000 to 2011 and identified all patients who had partial removal of an infected PTFE graft used for hemodialysis or peripheral bypass. These patients were examined for subsequent complications. Twenty-seven patients underwent 30 partial graft excisions with mean follow-up of 27 months. A total of 17% (5 of 30) of the partial graft resection procedures resulted in complications. Of 48 total remnants left behind at the arterial or venous anastomoses, reinfection occurred in 15%. Leaving a well-incorporated small 1-to 5-mm PTFE remnant at the arterial or venous anastomoses can be performed safely with a low risk of complications. © The Author(s) 2015.

  11. In vitro microbiologic evaluation of PTFE and cotton as spacer materials.

    Science.gov (United States)

    Paranjpe, Avina; Jain, Sumita; Alibhai, Karim J; Wadhwani, Chandur P; Darveau, Richard P; Johnson, James D

    2012-09-01

    To microbiologically evaluate the efficacy of cotton and polytetrafluoroethylene (PTFE) tape used as spacer materials. Twenty-six extracted human molars were restored using either cotton or PTFE tape as spacers under a standardized provisional restorative material (Cavit). The teeth were incubated for 7 days in a culture of Streptococcus gordonii or in liquid media alone. The spacers were removed and tested for bacterial contamination. The access cavities were also evaluated for bacterial contamination. Nine of 10 teeth with cotton spacers and one of 10 teeth with PTFE spacers were positive for S gordonii growth. The nine teeth in the cotton group also showed contamination of the access cavities. Even under optimal conditions, cotton spacers may cause leakage into the access cavities. Cotton fibers may serve as a route for bacterial contamination of the access cavities and root canal space. In contrast, PTFE tape did not provide an avenue for bacterial contamination.

  12. The production and characterization of Ptfe bonded Nd-Fe-B magnets

    International Nuclear Information System (INIS)

    Mokal, B.; Williams, A.J.; Hay, J.N.; Harris, I.R.

    1996-01-01

    A study of the processing and characteristics of PTFE bonded Nd Fe B magnets has been carried out. PTFE was used because of its low coefficient of friction, thus enabling its flow between the particles of Nd Fe B powder. PTFE also increases the resistance to corrosion of the magnet. In these investigations, the production of bonded magnets by cold compaction and by hot processing (HP) of MQ powders using PTFE as the binder was investigated . Magnetic, microstructural, and mechanical properties were investigated and are presented together with a correlation with the different processing techniques used. The corrosion behaviour of the hot pressed magnets was also investigated. These studies could lead to the development of simpler and more effective processing routes for the production of bonded magnets. (author)

  13. Preparation of Pt-PTFE hydrophobic catalyst for hydrogen-water isotope exchange

    International Nuclear Information System (INIS)

    Li Junhua; Kang Yi; Han Yande; Ruan Hao; Dou Qincheng; Hu Shilin

    2001-01-01

    The hydrophobic catalyst used in the hydrogen-water isotope exchange is prepared with Pt as the active metal, PTFE as the hydrophobic material, active carbon or silicon dioxide as the support. The isotope catalytic exchange reaction between hydrogen and water is carried out in the trickle bed and the effects of different carriers, mass fraction of Pt and PTFE on the catalytic activity are discussed. The experimental results show that the activity of Pt-C-PTFE hydrophobic catalyst with the ratio between PTFE and Pt-C from 1 to 2 is higher than other kinds of catalysts and the overall volume transfer coefficient is increased with the increasing of the hydrogen flow rate and reaction temperature

  14. Highly oriented poly(di-n-alkylsilylene) films on oriented PTFE substrates

    NARCIS (Netherlands)

    Frey, H.H.; Frey, Holger; Sheiko, Sergej; Sheiko, S.; Moller, M.; Möller, Martin; Wittmann, Jean-Claude; Lot, Bernard

    1993-01-01

    Highly oriented polysilylene layers have potential applications in electrophotography, nonlinear optics, display fabrication, and microlithography. The preparation of such layers by crystallization on a highly oriented PTFE substrate is reported, and their assessment by optical birefringence,

  15. Synthesis and characterization of c-PTFE-g-styrene copolymer by preirradiation method

    International Nuclear Information System (INIS)

    Oktaviani; Ambyah Suliwarno; Tita Puspitasari

    2011-01-01

    Crosslinked-poly(tetrafluoroethylene)-graf-styrene (c-PTFE-g-styrene) copolymer has been synthesized by copolymerization preirradiation method. Irradiation onto c-PTFE films was carried out by γ-ray with irradiation doses of 15, 30, and 45 kGy at room temperature. Styrene was grafted into irradiated c-PTFE films in the temperature range of between 600-90°C. Parameter observed in the grafting process was degree of grafting. The results showed that the degree of grafting increased with increasing of irradiation doses. The highest degree of grafting was 25,44 % obtained at temperature of 70°C and still increased up to 25,73% with increasing of the grafting time. The optimum grafting time was 2 hours. Chemical and physical properties of c-PTFE-g-styrene film were analyzed by IR spectrophotometer and Scanning Electron Microscopy (SEM). (author)

  16. Feasibility of Angioplasty and Stenting for Abdominal Aortic Lesions Adjacent to Previously Stented Visceral Artery Lesions in Patients with Takayasu Arteritis

    International Nuclear Information System (INIS)

    Joseph, George; George, Paul V.; Pati, Purendra Kumar; Chandy, Sunil Thomas

    2007-01-01

    Two young female patients with Takayasu arteritis presented with symptomatic long-segment abdominal aortic stenosis in the vicinity of previously deployed celiac and renal artery stents that projected markedly into the narrowed aortic lumen. Crushing or distortion of the visceral artery stents during aortic angioplasty was avoided by performing simultaneous or alternating balloon dilatations in the aorta and in the visceral artery stents. Consequently, the visceral artery stents remained patent and shortened longitudinally, allowing unhindered deployment of Wallstents in the adjacent aorta and abolition of a pressure gradient across the aortic lesions. Access to side branches covered by the Wallstent was obtained without difficulty, enabling the performance of balloon dilatation in multiple side branches and ostial stent deployment in a renal artery. These techniques could increase the scope of endovascular therapy in the treatment of patients with Takayasu arteritis

  17. Surveillance Duplex Ultrasonography of Stent Grafts for Popliteal Aneurysms.

    Science.gov (United States)

    Pineda, Danielle M; Troutman, Douglas A; Dougherty, Matthew J; Calligaro, Keith D

    2016-05-01

    Stent grafts, also known as covered stents, have become an increasingly acceptable treatment for popliteal artery aneurysms. However, endovascular exclusion confers lower primary patency compared to traditional open bypass and exclusion. The purpose of this study was to evaluate whether duplex ultrasonography (DU) can reliably diagnose failing stent grafts placed for popliteal artery aneurysms prior to occlusion. Between June 5, 2007, and March 11, 2014, 21 stent grafts (Viabahn; Gore, Flagstaff, Arizona) were placed in 19 patients for popliteal artery aneurysms. All patients had at least 1 follow-up duplex scan postoperatively. Mean follow-up was 28.9 months (9-93 months). Postoperative DU surveillance was performed in our Intersocietal Accreditation Commission noninvasive vascular laboratory at 1 week postprocedure and every 6 months thereafter. Duplex ultrasonography measured peak systolic velocities (PSVs) and ratio of adjacent PSVs (Vr) every 5 cm within the stent graft and adjacent arteries. We retrospectively classified the following factors as "abnormal DU findings": focal PSV > 300 cm/s, uniform PSVs 3.0. These DU criteria were derived from laboratory-specific data that we previously published on failing stent grafts placed for lower extremity occlusive disease. Four of the 21 stent grafts presented with symptomatic graft thrombosis within 6 months of a normal DU. Three of these 4 patients presented with rest pain and underwent thrombectomy (2) or vein bypass (1), and 1 elected for nonintervention for claudication. Our results suggest that surveillance DU using criteria established for grafts placed for occlusive disease may not be useful for predicting stent graft failure in popliteal artery aneurysms. © The Author(s) 2016.

  18. Radiation grafting of styrene and maleic anhydride onto PTFE membranes and sequent sulfonation for applications of vanadium redox battery

    International Nuclear Information System (INIS)

    Qiu Jingyi; Ni Jiangfeng; Zhai Maolin; Peng Jing; Zhou Henghui; Li Jiuqiang; Wei Genshuan

    2007-01-01

    Using γ-radiation technique, poly(tetrafluoroethylene) (PTFE) membrane was grafted with styrene (St) (PTFE-graft-PS) or binary monomers of St and maleic anhydride (MAn) (PTFE-graft-PS-co-PMAn), respectively. Then grafted membranes were further sulfonated with chlorosulfonic acid into ion-exchange membranes (denoted as PTFE-graft-PSSA and PTFE-graft-PSSA-co-PMAc, respectively) for application of vanadium redox battery (VRB). Micro-FTIR analysis indicated that PTFE was successfully grafted and sulfonated at the above two different conditions. However, a higher degree of grafting (DOG) was obtained in St/MAn binary system at the same dose due to a synergistic effect. Comparing with PTFE-graft-PSSA, PTFE-graft-PSSA-co-PMAc membrane showed higher water uptake and ion-exchange capacity (IEC) and lower area resistance (AR) at the same DOG. In addition, PTFE-graft-PSSA-co-PMAc with 6% DOG also showed a higher IEC and higher conductivity compared to Nafion membrane. Radiation grafting of PTFE in St/MAn binary system and sequent sulfonation is an appropriate method for preparing ion-exchange membrane of VRB

  19. The Mechanical and Reaction Behavior of PTFE/Al/Fe2O3 under Impact and Quasi-Static Compression

    Directory of Open Access Journals (Sweden)

    Jun-yi Huang

    2017-01-01

    Full Text Available Quasi-static compression and drop-weight test were used to characterize the mechanical and reaction behavior of PTFE/Al/Fe2O3 composites. Two kinds of PTFE/Al/Fe2O3 composites were prepared with different mass of PTFE, and the reaction phenomenon and stress-strain curves were recorded; the residuals after reaction were analyzed by X-ray diffraction (XRD. The results showed that, under quasi-static compression condition, the strength of the materials is increased (from 37.1 Mpa to 77.2 Mpa with the increase of PTFE, and the reaction phenomenon occurred only in materials with high PTFE content. XRD analysis showed that the reaction between Al and Fe2O3 was not triggered with identical experimental conditions. In drop-weight tests, PTFE/Al/Fe2O3 specimens with low PTFE content were found to be more insensitive by high-speed photography, and a High Temperature Metal Slag Spray (HTMSS phenomenon was observed in both kinds of PTFE/Al/Fe2O3 composites, indicating the existence of thermite reaction, which was confirmed by XRD. In PTFE/Al/Fe2O3 system, the reaction between PTFE and Al precedes the reaction between Al and Fe2O3.

  20. Medium-term follow-up after deployment of ultraflex expandable metallic stents to manage endobronchial pathology.

    Science.gov (United States)

    Madden, Brendan P; Park, John E S; Sheth, Abhijat

    2004-12-01

    Between March 1997 and March 2004 we deployed 80 Ultraflex metallic expandable stents (Boston Scientific, Waterson, MA) in 69 patients under direct vision using rigid bronchoscopy. We report our medium- to long-term experience in patients for whom these stents were deployed. To date 15 patients have been followed for more than 1 year (median 41 months, range 12 to 83 months) after stent deployment. Indications for stenting in these patients were neoplasia (5), stricture (5), airway malacia (1), iatrogenic tracheal tear (1), and compression from an aortic aneurysm (1), a right interrupted aortic arch (1), and a right brachiocephalic artery aneurysm with tracheomalacia (1). Ten tracheal stents (9 covered, 1 uncovered) and 10 bronchial stents (8 uncovered, 2 covered) were inserted, and 5 patients received two stents. Five of these patients experienced no long-term problems. Complications included troublesome halitosis (5), which was difficult to treat despite various antibiotic regimes; granulation tissue formation above and below the stent that was successfully treated with low-power Nd:YAG laser therapy (7); and metal fatigue (1). We did not encounter stent migration. We conclude that Ultraflex expandable metallic stents have an important role in the management of selected patients with diverse endobronchial pathologies and are well tolerated in the long-term. Although associated granulation tissue can be successfully treated with Nd:YAG laser, halitosis can be a difficult problem to address.

  1. Study on the performance of MoS2 modified PTFE composites by molding process

    Science.gov (United States)

    Ma, Weiqiang; Hou, Genliang; Bi, Song; Li, Ping; Li, Penghui

    2017-10-01

    MoS2 filled PTFE composites were prepared by cold pressing and sintering molding. The compressive and creep properties of composite materials were analyzed by controlling the size of molded composites during molding. The results show that the composites have the best compressive and creep resistance when the molding pressure is 55 MPa in the MoS2 composites with 15% mass fraction, which is a practical reference for the preparation of MoS2-modified PTFE composites.

  2. Thermoluminescence sensitivity variations in LiF PTFE dosemeters incurred by improper handling procedures

    CERN Document Server

    Mason, E W; MacKinlay, Alistair F; Saunders, D

    1975-01-01

    A systematic study of some anomalous darkening effects and thermoluminescence sensitivity variations observed in LiF:PTFE thermoluminescent dosemeters is described. Various likely causes of such effects have been investigated. The manufacturer's recommended cleaning procedures have been found to be inadequate and, in some cases, have been found to actually promote discolouration of the dosemeters. Recommendations are given for the successful use of LiF:PTFE thermoluminescent dosemeters in personal dosimetry.

  3. Acid Aging Effects on Surfaces of PTFE Gaskets Investigated by Thermal Analysis

    Directory of Open Access Journals (Sweden)

    C. Fragassa

    2016-12-01

    Full Text Available This paper investigates the effect of a prolonged acid attack on the surface of PTFE by Thermogravimetric Analysis (TGA and Differential Scanning Calorimetry (DSC. PTFE is very non-reactive, partly because of the strength of carbon–fluorine bonds and for its high crystallinity, and, as a consequence, it is often used in containers and pipework with reactive and corrosive chemicals. The PTFE under analysis is commercialized by two alternative producers in form of Teflon tapes. These tapes are adopted, as gaskets, in process plants where tires moulds are cleaned by acid solutions inside a multistage ultrasonic process. In this case, PTFE shows, in a relatively short operation time, inexplicably phenomena of surface degradation, which could be related, in general terms, to an acid attack. But, even considering the combined effect of ultrasonic waves, temperature, humidity and acid attack, the PTFE properties of resistance nominally exclude the risk of the extreme erosion phenomena as observed. The present experimental research aim at investigating this contradiction. A possible explanation could be related to the presence in the cleaning solution of unexpected fluorides, able to produce fluorinating agents and, thus, degrade carbon-fluorine bonds. Considering more the 300 chemical elements a tire compound consists in, it is really complex to preserve the original chemical composition of the cleaning solution. In this research PTFE samples have been treated with different mixtures of acids with the aim at investigating the different aging effects. The thermal analysis has permitted the experimental characterization of PTFE surface properties after acid attack, providing evidence of the degradation phenomena. In particular, the different acid treatments adopted for accelerating the aging of gaskets have highlighted the different behaviour of the PTFE matrix, but also differences between manufacturers.

  4. Hepatocellular Carcinoma Complicated by Gastroduodenal Obstruction: Palliative Treatment with Metallic Stent Placement

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ye Jin; Kim, Jin Hyoung, E-mail: m1fenew@daum.net; Song, Ho-Young; Park, Jung-Hoon; Na, Han Kyu; Kim, Pyeong Hwa; Fan, Yong [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Asan Medical Center (Korea, Republic of)

    2012-10-15

    Purpose: To evaluate the clinical effectiveness of self-expandable metallic stents in seven patients with malignant gastroduodenal obstruction caused by inoperable hepatocellular carcinoma (HCC). Methods: Seven patients with gastroduodenal obstruction caused by advanced HCC underwent metallic stent placement from 2003 to 2010. These patients had total dysphagia (n = 5) or were able to eat only liquids (n = 2) before stent placement. Patients had Eastern Cooperative Oncology Group performance scores of 2 or 3, and Child-Pugh classification B or C. Results: Stent placement was technically successful in all seven patients (100%) and clinically successful in six (86%). Five patients could eat a soft diet, and one patient tolerated regular diet after stent placement. Stent-related obstructive jaundice occurred in one patient. One patient had hematemesis 11 days after stent placement. Overall mean survival was 51 days (range, 10-119 days). Stent patency was preserved in six patients with clinical success until death. Conclusion: Placement of a covered self-expandable metallic stent may offer good palliation in patients with gastroduodenal obstruction due to advanced HCC.

  5. Evaluating the interaction of a tracheobronchial stent in an ovine in-vivo model.

    Science.gov (United States)

    McGrath, Donnacha J; Thiebes, Anja Lena; Cornelissen, Christian G; O'Brien, Barry; Jockenhoevel, Stefan; Bruzzi, Mark; McHugh, Peter E

    2018-04-01

    Tracheobronchial stents are used to restore patency to stenosed airways. However, these devices are associated with many complications such as stent migration, granulation tissue formation, mucous plugging and stent strut fracture. Of these, granulation tissue formation is the complication that most frequently requires costly secondary interventions. In this study a biomechanical lung modelling framework recently developed by the authors to capture the lung in-vivo stress state under physiological loading is employed in conjunction with ovine pre-clinical stenting results and device experimental data to evaluate the effect of stent interaction on granulation tissue formation. Stenting is simulated using a validated model of a prototype covered laser-cut tracheobronchial stent in a semi-specific biomechanical lung model, and physiological loading is performed. Two computational methods are then used to predict possible granulation tissue formation: the standard method which utilises the increase in maximum principal stress change, and a newly proposed method which compares the change in contact pressure over a respiratory cycle. These computational predictions of granulation tissue formation are then compared to pre-clinical stenting observations after a 6-week implantation period. Experimental results of the pre-clinical stent implantation showed signs of granulation tissue formation both proximally and distally, with a greater proximal reaction. The standard method failed to show a correlation with the experimental results. However, the contact change method showed an apparent correlation with granulation tissue formation. These results suggest that this new method could be used as a tool to improve future device designs.

  6. Hepatocellular Carcinoma Complicated by Gastroduodenal Obstruction: Palliative Treatment with Metallic Stent Placement

    International Nuclear Information System (INIS)

    Lee, Ye Jin; Kim, Jin Hyoung; Song, Ho-Young; Park, Jung-Hoon; Na, Han Kyu; Kim, Pyeong Hwa; Fan, Yong

    2012-01-01

    Purpose: To evaluate the clinical effectiveness of self-expandable metallic stents in seven patients with malignant gastroduodenal obstruction caused by inoperable hepatocellular carcinoma (HCC). Methods: Seven patients with gastroduodenal obstruction caused by advanced HCC underwent metallic stent placement from 2003 to 2010. These patients had total dysphagia (n = 5) or were able to eat only liquids (n = 2) before stent placement. Patients had Eastern Cooperative Oncology Group performance scores of 2 or 3, and Child-Pugh classification B or C. Results: Stent placement was technically successful in all seven patients (100%) and clinically successful in six (86%). Five patients could eat a soft diet, and one patient tolerated regular diet after stent placement. Stent-related obstructive jaundice occurred in one patient. One patient had hematemesis 11 days after stent placement. Overall mean survival was 51 days (range, 10–119 days). Stent patency was preserved in six patients with clinical success until death. Conclusion: Placement of a covered self-expandable metallic stent may offer good palliation in patients with gastroduodenal obstruction due to advanced HCC.

  7. Endoscopic removal and trimming of distal self-expandable metallic biliary stents

    Science.gov (United States)

    Ishii, Kentaro; Itoi, Takao; Sofuni, Atsushi; Itokawa, Fumihide; Tsuchiya, Takayoshi; Kurihara, Toshio; Tsuji, Shujiro; Ikeuchi, Nobuhito; Umeda, Junko; Moriyasu, Fuminori; Tsuchida, Akihiko

    2011-01-01

    AIM: To evaluate the efficacy and safety of endoscopic removal and trimming of self-expandable metallic stents (SEMS). METHODS: All SEMS had been placed for distal biliary strictures. Twenty-seven endoscopic procedures were performed in 19 patients in whom SEMS (one uncovered and 18 covered) removal had been attempted, and 8 patients in whom stent trimming using argon plasma coagulation (APC) had been attempted at Tokyo Medical University Hospital. The APC settings were: voltage 60-80 W and gas flow at 1.5 L/min. RESULTS: The mean stent indwelling period for all patients in whom stent removal had been attempted was 113.7 ± 77.6 d (range, 8-280 d). Of the 19 patients in whom removal of the SEMS had been attempted, the procedure was successful in 14 (73.7%) without procedure-related adverse events. The indwelling period in the stent removable group was shorter than that in the unremovable group (94.9 ± 71.5 d vs 166.2 ± 76.2 d, P = 0.08). Stent trimming was successful for all patients with one minor adverse event consisting of self-limited hemorrhage. Trimming time ranged from 11 to 16 min. CONCLUSION: Although further investigations on larger numbers of cases are necessary to accumulate evidence, the present data suggested that stent removal and stent trimming is feasible and effective for stent-related complications. PMID:21677835

  8. Preparation, Properties, and Self-Assembly Behavior of PTFE-Based Core-Shell Nanospheres

    International Nuclear Information System (INIS)

    Sparnacci, K.; Antonioli, D.; Deregibus, S.; Laus, M.; Zuccheri, G.; Boarino, L.; De Leo, N.; Comoretto, D.

    2012-01-01

    Nano sized PTFE-based core-shell particles can be prepared by emulsifier-free seed emulsion polymerization technique starting from spherical or rod-like PTFE seeds of different size. The shell can be constituted by the relatively high Tg polystyrene and polymethylmethacrylate as well as by low Tg polyacrylic copolymers. Peculiar thermal behavior of the PTFE component is observed due to the high degree of PTFE compartmentalization. A very precise control over the particle size can be exerted by properly adjusting the ratio between the monomers and the PTFE seed. In addition, the particle size distribution self-sharpens as the ratio monomer/PTFE increases. Samples with uniformity ratios suited to build 2D and 3D colloidal crystals are easily prepared. In particular, 2D colloidal crystal of spheres leads to very small 2D nanostructuration, useful for the preparation of masks with a combination of nanosphere lithography and reactive ion etching. 3D colloidal crystals were also obtained featuring excellent opal quality, which is a direct consequence of the monodispersity of colloids used for their growth.

  9. Synchrotron radiation induced direct photo-etching and surface modification of PTFE

    International Nuclear Information System (INIS)

    Oshima, Akihiro; Washio, Masakazu

    2003-01-01

    In the first part of this article, we have described and discussed the measurement results of etching rates by direct photo-etching using Synchrotron Radiation (SR) for various kind of crosslinked PTFEs, which were prepared by different crosslinking doses, comparing with the non-crosslinked PTFE. It has been found that the etching rates obtained for crosslinked PTFE were much larger than that of non-crosslinked one. These results are not described by simple consideration such as the G values of main chain scission. We propose that the etching rates should be discussed by the complex mechanism through at least two different steps such as polymer decomposition and fragment desorption. In the second part of the article, we have described and discussed the abnormal reaction induced at the surface region after the SR etching for non-crosslinked PTFE. Through the measurements using DSC and solid state 19 F-NMR, we have confirmed the crosslinking reaction of PTFE even in solid state PTFE. This should be induced by the very high density radical formation in very thin area of PTFE films by SR radiation. (author)

  10. Preparation, Properties, and Self-Assembly Behavior of PTFE-Based Core-Shell Nanospheres

    Directory of Open Access Journals (Sweden)

    Katia Sparnacci

    2012-01-01

    Full Text Available Nanosized PTFE-based core-shell particles can be prepared by emulsifier-free seed emulsion polymerization technique starting from spherical or rod-like PTFE seeds of different size. The shell can be constituted by the relatively high Tg polystyrene and polymethylmethacrylate as well as by low Tg polyacrylic copolymers. Peculiar thermal behavior of the PTFE component is observed due to the high degree of PTFE compartmentalization. A very precise control over the particle size can be exerted by properly adjusting the ratio between the monomers and the PTFE seed. In addition, the particle size distribution self-sharpens as the ratio monomer/PTFE increases. Samples with uniformity ratios suited to build 2D and 3D colloidal crystals are easily prepared. In particular, 2D colloidal crystal of spheres leads to very small 2D nanostructuration, useful for the preparation of masks with a combination of nanosphere lithography and reactive ion etching. 3D colloidal crystals were also obtained featuring excellent opal quality, which is a direct consequence of the monodispersity of colloids used for their growth.

  11. Ion beam deposition of DLC and nitrogen doped DLC thin films for enhanced haemocompatibility on PTFE

    International Nuclear Information System (INIS)

    Srinivasan, S.; Tang, Y.; Li, Y.S.; Yang, Q.; Hirose, A.

    2012-01-01

    Diamond-like carbon (DLC) and N-doped DLC (DLC:N) thin films have been synthesized on polytetrafluroethylene (PTFE) and silicon wafers using ion beam deposition. Raman spectroscopy, atomic force microscopy, X-ray photoelectron spectroscopy and scanning electron microscopy were used to study the structural and morphological properties of the coated surface. The results show that the ion beam deposited DLC thin films exhibit high hardness and Young's modulus, low coefficient of friction and high adhesion to the substrate. Low concentration of nitrogen doping in DLC improves the mechanical properties and reduces the surface roughness. DLC coating decreases the surface energy and improves the wettability of PTFE. The platelet adhesion results show that the haemocompatibility of DLC coated PTFE, especially DLC:N coated PTFE, has been significantly enhanced as compared with uncoated PTFE. SEM observations show that the platelet reaction on the DLC and DLC:N coated PTFE was minimized as the platelets were much less aggregated and activated.

  12. Clinical Outcomes of Self-Expandable Metal Stents for Malignant Rectal Obstruction.

    Science.gov (United States)

    Lee, Hyun Jung; Hong, Sung Pil; Cheon, Jae Hee; Kim, Tae Il; Kim, Won Ho; Park, Soo Jung

    2018-01-01

    Self-expandable metal stents are widely used to treat malignant colorectal obstruction. However, data on clinical outcomes of stent placement for rectal obstruction specifically are lacking. We aimed to investigate the clinical outcomes of self-expandable metal stents in malignant rectal obstruction in comparison with those in left colonic obstruction and to identify factors associated with clinical failure and complication. This was a retrospective study. The study was conducted at a tertiary care center. Between January 2005 and December 2013, medical charts of patients who underwent stent placement for malignant rectal or left colonic obstruction were reviewed retrospectively. Study intervention included self-expandable metal stent placement. Technical success, clinical success, and complications were measured. Technical success rates for the 2 study groups (rectum vs left colon, 93.5% vs 93.1%; p = 0.86) did not differ significantly; however, the clinical success rate was lower in patients with rectal obstruction (85.4% vs 92.1%; p = 0.02). In addition, the complication rate was higher in patients with rectal obstruction (37.4% vs 25.1%; p = 0.01). Patients with rectal obstruction showed higher rates of obstruction because of extracolonic malignancy (33.8% vs 15.8%; p stent use for palliation (78.6% vs 56.3%; p stent usage to be independent risk factors for clinical failure. Factors predictive of complications in the palliative group were total obstruction, obstruction because of extracolonic malignancy, and covered stent usage. This was a retrospective, single-center study. The efficacy and safety of stent placement for malignant rectal obstruction were comparable with those for left colonic obstruction. However, obstruction attributed to extracolonic malignancy, use of covered stents, and total obstruction negatively impacted clinical outcomes of self-expandable metal stent placement and must be considered by endoscopists. See Video Abstract at http

  13. Determination of Stent Stenosis: An In Vivo Experimental Comparison of Intravascular Ultrasound and Angiography with Histology

    International Nuclear Information System (INIS)

    Schuermann, Karl; Vorwerk, Dierk; Uppenkamp, Robert; Klosterhalfen, Bernd; Buecker, Arno; Guenther, Rolf W.

    1998-01-01

    Purpose: To compare intravascular ultrasound (IVUS) and angiography with histology in determining the degree of stent stenosis in an in vivo experiment. Methods: In 16 sheep, a total of 64 stents were implanted into the external iliac arteries. Two stents were inserted on either side. Patency was followed by angiography and IVUS. Four types of stent were used: two Dacron-covered (Cragg Endopro and heparinized Cragg Endopro) and two non-covered (Cragg and Memotherm stents). Eight animals were killed after 1 month, eight others after 6 months. Histological sections were prepared from the stented vessels. Measurements of the patent and total stent diameters determined by IVUS, angiography, and histology were compared. Results: Correlation between IVUS and angiography was 0.75, between IVUS and histology 0.77, and between angiography and histology 0.85. A mean stent stenosis of 17 ± 11% (range 0-51%) was found on angiography, of 10 ± 11% (0-46%) on IVUS, and of 20 ± 11% (4%-49%) on histology. In comparison with histology, IVUS underestimated the degree of stenosis by 10 ± 8%, and angiography underestimated it by 3 ± 6%. Resolution of IVUS was calculated to be about 0.35 mm and that of angiography to be about 0.15 mm. Conclusion: Under experimental conditions, IVUS was not superior to angiography in determining the degree of stent stenosis in long-segment stenoses of iliac artery stents, when measurements were correlated with histology. Angiography is sufficient for following the patency of iliac artery stents

  14. Angioplasty and stent placement - carotid artery

    Science.gov (United States)

    ... medlineplus.gov/ency/article/002953.htm Angioplasty and stent placement - carotid artery To use the sharing features ... to remove plaque buildup ( endarterectomy ) Carotid angioplasty with stent placement Description Carotid angioplasty and stenting (CAS) is ...

  15. An automatic algorithm for detecting stent endothelialization from volumetric optical coherence tomography datasets

    Energy Technology Data Exchange (ETDEWEB)

    Bonnema, Garret T; Barton, Jennifer K [College of Optical Sciences, University of Arizona, Tucson, AZ (United States); Cardinal, Kristen O' Halloran [Biomedical and General Engineering, California Polytechnic State University (United States); Williams, Stuart K [Cardiovascular Innovation Institute, University of Louisville, Louisville, KY 40292 (United States)], E-mail: barton@u.arizona.edu

    2008-06-21

    Recent research has suggested that endothelialization of vascular stents is crucial to reducing the risk of late stent thrombosis. With a resolution of approximately 10 {mu}m, optical coherence tomography (OCT) may be an appropriate imaging modality for visualizing the vascular response to a stent and measuring the percentage of struts covered with an anti-thrombogenic cellular lining. We developed an image analysis program to locate covered and uncovered stent struts in OCT images of tissue-engineered blood vessels. The struts were found by exploiting the highly reflective and shadowing characteristics of the metallic stent material. Coverage was evaluated by comparing the luminal surface with the depth of the strut reflection. Strut coverage calculations were compared to manual assessment of OCT images and epi-fluorescence analysis of the stented grafts. Based on the manual assessment, the strut identification algorithm operated with a sensitivity of 93% and a specificity of 99%. The strut coverage algorithm was 81% sensitive and 96% specific. The present study indicates that the program can automatically determine percent cellular coverage from volumetric OCT datasets of blood vessel mimics. The program could potentially be extended to assessments of stent endothelialization in native stented arteries.

  16. 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.

  17. Afterloading intracavitary irradiation and expanding stent for malignant biliary obstruction

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimura, Hitoshi; Sakaguchi, Hiroshi; Yoshioka, Tetsuya and others

    1989-02-01

    A double lumen catheter was developed as an apllicator for the remote afterloading (RALS) of /sup 60/Co source for the intracavitary irradiation of an obstructed common bile duct caused by carcinoma of the gallbladder. This was followed by the placement of nylon-covered expandable metallic stents to maintain patency. This combination effectively provided palliation. (author).

  18. The Scandinavian Propaten(®) trial - 1-year patency of PTFE vascular prostheses with heparin-bonded luminal surfaces compared to ordinary pure PTFE vascular prostheses - a randomised clinical controlled multi-centre trial.

    Science.gov (United States)

    Lindholt, J S; Gottschalksen, B; Johannesen, N; Dueholm, D; Ravn, H; Christensen, E D; Viddal, B; Flørenes, T; Pedersen, G; Rasmussen, M; Carstensen, M; Grøndal, N; Fasting, H

    2011-05-01

    To compare 1-year potencies' of heparin-bonded PTFE [(Hb-PTFE) (Propaten(®))] grafts with those of ordinary polytetraflouroethylene (PTFE) grafts in a blinded, randomised, clinically controlled, multi-centre study. Eleven Scandinavian centres enrolled 569 patients with chronic functional or critical lower limb ischaemia who were scheduled to undergo femoro-femoral bypass or femoro-poplitaeal bypass. The patients were randomised 1:1 stratified by centre. Patency was assessed by duplex ultrasound scanning. A total of 546 patients (96%) completed the study with adequate follow-up. Perioperative bleeding was, on average, 370 ml with PTFE grafts and 399 ml with Heparin-bonded PTFE grafts (p = 0.32). Overall, primary patency after 1 year was 86.4% for Hb-PTFE grafts and 79.9% for PTFE grafts (OR = 0.627, 95% CI: 0.398; 0.989, p = 0.043). Secondary patency was 88% in Hb-PTFE grafts and 81% in PTFE grafts (OR = 0.569 (0.353; 0.917, p = 0.020)). Subgroup analyses revealed that significant reduction in risk (50%) was observed when Hb-PTFE was used for femoro-poplitaeal bypass (OR = 0.515 (0.281; 0.944, p = 0.030)), and a significant reduction in risk (50%) was observed with Hb-PTFE in cases with critical ischaemia (OR = 0.490 (0.249; 0.962, p = 0.036)). The Hb-PTFE graft significantly reduced the overall risk of primary graft failure by 37%. Risk reduction was 50% in femoro-poplitaeal bypass cases and in cases with critical ischaemia. Copyright © 2011. Published by Elsevier Ltd.

  19. Delayed complications after flow-diverter stenting: reactive in-stent stenosis and creeping stents.

    Science.gov (United States)

    Cohen, José E; Gomori, John Moshe; Moscovici, Samuel; Leker, Ronen R; Itshayek, Eyal

    2014-07-01

    We assessed the frequency and severity of changes in stent configuration and location after the treatment of intracranial aneurysms, and patterns of in-stent stenosis. We retrospectively reviewed data for consecutive aneurysm patients managed with endovascular implantation of flow-diverter stents (Silk Flow Diverter [Balt Extrusion, Montmorency, France] and Pipeline Embolization Device [ev3/Coviden, Minneapolis, MN, USA]) from October 2011 to July 2012. Routine 2, 6, 9-12, and 16-20 month follow-up angiograms were compared, with a focus on changes in stent configuration and location from immediately after deployment to angiographic follow-up, and the incidence and development of in-stent stenosis. Thirty-four patients with 42 aneurysms met inclusion criteria. The Silk device was implanted in 16 patients (47%, single device in 15), the Pipeline device in 18 (53%, single device in 16). On first follow-up angiography, in-stent stenosis was observed in 38% of Silk devices and 39% of Pipeline devices. In-stent stenosis was asymptomatic in 12 of 13 patients. One woman presented with transient ischemic attacks and required stent angioplasty due to end tapering and mild, diffuse in-stent stenosis. Configuration and location changes, including stent creeping and end tapering were seen in 2/16 patients (13%) with Silk devices, and 0/18 patients with Pipeline devices. We describe stent creeping and end tapering as unusual findings with the potential for delayed clinical complications. In-stent stenosis, with a unique behavior, is a frequent angiographic finding observed after flow-diverter stent implant. The stenosis is usually asymptomatic; however, close clinical and angiographic monitoring is mandatory for individualized management. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Dextran grafting on PTFE surface for cardiovascular applications

    Science.gov (United States)

    Michel, Eléonore C; Montaño-Machado, Vanessa; Chevallier, Pascale; Labbé-Barrère, Amélie; Letourneur, Didier; Mantovani, Diego

    2014-01-01

    The modification of biomaterial surfaces with biomolecules influences the biological response. In this work, caboxymethyldextrans (CMD) with different degrees of substitution have been grafted to surfaces by introduction of amino moieties directly onto the substrate surface. Polytetrafluoroethylene was selected as a model substrate for biomaterial as it is already largely used for cardiovascular clinical applications. Firstly, CMD polymers were characterized by FTIR, 1H-NMR, and conductimetric titration. Then, the coatings have been analyzed by XPS to confirm the grafting and determine the composition. Once characterized, biological performances of CMD coatings were investigated. The hemocompatibility was ascertained using the free hemoglobin method. The effects on endothelial and smooth muscle cell adhesion were also studied. Results indicated that CMD at a 0.2 substitution degree, significantly influenced the biological property of PTFE by exhibiting non-thrombogenic properties as well as enhancing endothelial cell adhesion along with limiting smooth muscle cell adhesion. This work suggested the creation of versatile pro-active biomaterials suitable for different biomedical applications. PMID:25482414

  1. Angioplasty and stent - heart - discharge

    Science.gov (United States)

    Drug-eluting stents - discharge; PCI - discharge; Percutaneous coronary intervention - discharge; Balloon angioplasty - discharge; Coronary angioplasty - discharge; Coronary artery angioplasty - discharge; Cardiac ...

  2. Indications for stenting during thrombolysis

    DEFF Research Database (Denmark)

    Bækgaard, N; Broholm, R; Just, Sven Richardt Lundgren

    2013-01-01

    of a stent in this position is the treatment of choice facilitating the venous flow into an unobstructed outflow tract either from the femoral vein or the deep femoral vein or both. The stent, made of stainless steel or nitinol, has to be self-expandable and flexible with radial force to overcome...... the challenges in this low-pressure system. The characteristics of the anatomy with external compression and often a curved vein segment with diameter difference make stent placement necessary. Ballooning alone has no place in this area. The proportion of inserted stents varies in the published materials...

  3. Comparative analysis of intraluminal radiation stent in treatment of advanced esophageal carcinoma

    International Nuclear Information System (INIS)

    Guo Jinhe; Teng Gaojun; Zhu Guangyu; He Shicheng; Fang Wen; Deng Gang; Li Guozhao

    2007-01-01

    Objective: To compare the clinical effectiveness of intraluminal radiation stent with that of common covered stent to palliate dysphagia in advanced esophageal cancer. Methods: Fifty three cases were randomly assigned to the experimental group (Group A, n=27) and the control group (Group B, n26). Radiation stents were placed in Group A and common covered stents were placed in Group B. A randomized trial was performed to compare the two groups with respect to complications, relief of dysphagia, and overall survival period. Results: The placement of stents were successful in all the 53 patients. In Group A, no leakage of radiation source was observed through ECT examination, and no displacement of radiation seeds was found through radiography. The follow-up CT showed reduced lesion size compared to presurgical lesion. Three of the 5 patients who underwent uncovered radiation stent placement showed complete necrosis and inflammatory hyperblastosis in tumor tissue adjacent to radiation particles at 2 months follow-up. The lumen of the stents were smooth and had no overgrowth of tumor tissue. Granulation hyperplasia was found at both ends of the stents, prominent at the proximal ends, The incidence of stent- related complications had no significant difference between group A and group B (test, P>0.05). Dysphasia resolved significantly after stent placement in both groups. The improvement of dysphasia was more significant in Group A than in Group B after 2 months of stent placement (1.37±0.56 in group A, 1.82±0.50 in group B,P=0.004). The median survival period was longer in Group A than in Group B (7 months vs 4 months ). The mean survival period was also longer in Group A than in Group B (8.3 months vs 3.5 months). There was a statistically significant difference in the survival period between the two groups (P<0.01). Conclusion: Intraluminal radiation esophageal stent can not only palliate dysphagia but also restrain tumor growth. Palliation period of dysphagia and

  4. The stenting strategy of drug-eluting stents for coronary artery disease in patients on dialysis

    Directory of Open Access Journals (Sweden)

    Hiroshi Fujita

    2014-12-01

    Full Text Available Background: Reports regarding the relationship between the length and diameter of implanted drug-eluting stents and clinical and angiographic outcomes in dialysis patients are limited. Aim: We investigated the efficiency of drug-eluting stents for coronary artery disease in patients on dialysis from the viewpoint of stent sizing. Methods: Sirolimus-eluting stents were implanted in 88 lesions and bare metal stents were implanted in 43 lesions. We compared stenting strategy, major adverse cardiac events, and angiographic results between sirolimus-eluting stent and bare metal stent groups. Results: Stent diameter was smaller and stent length was longer in the sirolimus-eluting stent group than in the bare metal stent group in our routine practices. There was no significant between-group difference in late diameter loss. Rates of angiographic restenosis and target lesion revascularization were significantly higher in the sirolimus-eluting stent group than in the bare metal stent group. Although stent length was significantly longer and stent diameter was smaller in the sirolimus-eluting stent group, sirolimus-eluting stents did not improve the subsequent clinical and angiographic results compared with bare metal stents in dialysis patients. Conclusion: In dialysis patients, a longer length and/or smaller diameter sirolimus-eluting stent implantation was associated with high rates of restenosis and target lesion revascularization compared with bare metal stents.

  5. 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.

  6. Emulsion Electrospinning of Polytetrafluoroethylene (PTFE) Nanofibrous Membranes for High-Performance Triboelectric Nanogenerators.

    Science.gov (United States)

    Zhao, Pengfei; Soin, Navneet; Prashanthi, Kovur; Chen, Jinkai; Dong, Shurong; Zhou, Erping; Zhu, Zhigang; Narasimulu, Anand Arcot; Montemagno, Carlo D; Yu, Liyang; Luo, Jikui

    2018-02-14

    Electrospinning is a simple, versatile technique for fabricating fibrous nanomaterials with the desirable features of extremely high porosities and large surface areas. Using emulsion electrospinning, polytetrafluoroethylene/polyethene oxide (PTFE/PEO) membranes were fabricated, followed by a sintering process to obtain pure PTFE fibrous membranes, which were further utilized against a polyamide 6 (PA6) membrane for vertical contact-mode triboelectric nanogenerators (TENGs). Electrostatic force microscopy (EFM) measurements of the sintered electrospun PTFE membranes revealed the presence of both positive and negative surface charges owing to the transfer of positive charge from PEO which was further corroborated by FTIR measurements. To enhance the ensuing triboelectric surface charge, a facile negative charge-injection process was carried out onto the electrospun (ES) PTFE subsequently. The fabricated TENG gave a stabilized peak-to-peak open-circuit voltage (V oc ) of up to ∼900 V, a short-circuit current density (J sc ) of ∼20 mA m -2 , and a corresponding charge density of ∼149 μC m -2 , which are ∼12, 14, and 11 times higher than the corresponding values prior to the ion-injection treatment. This increase in the surface charge density is caused by the inversion of positive surface charges with the simultaneous increase in the negative surface charge on the PTFE surface, which was confirmed by using EFM measurements. The negative charge injection led to an enhanced power output density of ∼9 W m -2 with high stability as confirmed from the continuous operation of the ion-injected PTFE/PA6 TENG for 30 000 operation cycles, without any significant reduction in the output. The work thus introduces a relatively simple, cost-effective, and environmentally friendly technique for fabricating fibrous fluoropolymer polymer membranes with high thermal/chemical resistance in TENG field and a direct ion-injection method which is able to dramatically improve the

  7. Retrievable Airway Stent Placement for Stoma Stricture after Anterior Mediastinal Tracheostomy: Case Report

    International Nuclear Information System (INIS)

    Hwang, Jae Yeon; Shin, Ji Hoon; Kim, Yong Hee; Song, Ho Young; Kim, Jin Hyoung; Lee, Yeoun Joo

    2013-01-01

    Anterior mediastinal tracheostomy (AMT) is performed to establish an airway after resection of advanced tumors in the cervicothoracic region. We report a case of successful placement of a covered retrievable self-expandable nitinol stent for a stoma stricture that developed after AMT in a patient with adenoid cystic carcinoma of the trachea. Two stent placements and removals, at two and three months after their initial placement, were performed due to loosening of the stents. Although we did not achieve long-term results as the patient died of massive hemorrhage, the stent placement was both feasible and safe, thus suggesting that temporary stent placement may be a valuable option for treating stoma stricture occurring after AMT.

  8. Retrievable Airway Stent Placement for Stoma Stricture after Anterior Mediastinal Tracheostomy: Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Jae Yeon; Shin, Ji Hoon; Kim, Yong Hee; Song, Ho Young; Kim, Jin Hyoung [Dept. of University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of); Lee, Yeoun Joo [Dept. of Pediatrics, Pusan National University Children' s Hospital, Yangsan (Korea, Republic of)

    2013-06-15

    Anterior mediastinal tracheostomy (AMT) is performed to establish an airway after resection of advanced tumors in the cervicothoracic region. We report a case of successful placement of a covered retrievable self-expandable nitinol stent for a stoma stricture that developed after AMT in a patient with adenoid cystic carcinoma of the trachea. Two stent placements and removals, at two and three months after their initial placement, were performed due to loosening of the stents. Although we did not achieve long-term results as the patient died of massive hemorrhage, the stent placement was both feasible and safe, thus suggesting that temporary stent placement may be a valuable option for treating stoma stricture occurring after AMT.

  9. 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.

  10. 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.

  11. Endoscopically placed stents: a useful alternative for the management of refractory benign cervical esophageal stenosis

    Directory of Open Access Journals (Sweden)

    Óscar Nogales

    Full Text Available Introduction: Benign esophageal strictures are relatively frequent and can severely affect the quality of life of a patient. Stenting has been proposed for the treatment of refractory cases. Lesions affecting the cervical esophagus are more difficult to treat, and the placement of stents in this location has traditionally been restricted due to potential adverse events. The aim of this study was to describe the efficacy and safety of endoscopic stenting in the management of refractory benign cervical esophageal strictures (RBCES in a single-center cohort study. Methods: We analyzed 12 patients with RBCES (Kochman's criteria and severe dysphagia. We recorded previous endoscopic treatments, stricture characteristics and demographic data. The two types of stents used were fully covered self-expandable metallic stents (FCSEMS and uncovered biodegradable stents (BDS. FCSEMS were removed eight weeks after placement, and BDS were followed-up until degradation. We assessed technical and clinical success, rate of stricture recurrence and adverse events. Results: The mean age of participants was 64 years (range 30-85. A total of 23 stents (13 FCSEMS and 10 BDS were placed in 12 patients (median 1.92, range 1-4. The technical success rate was 96% (22/23 stents. Eight patients (66.6% maintained adequate oral intake at the end of follow-up (median 33.3 months, range 3-84 months. Migration was recorded in 7/23 stents (30.4% and epithelial hyperplasia in 4/23 stents (17.4%. No severe adverse events were noted. All patients complained of minor cervical pain after placement that was well controlled with mild analgesia. Conclusions: Endoscopic stent therapy seems to be effective and safe in the management of RBCES.

  12. Endoscopically placed stents: a useful alternative for the management of refractory benign cervical esophageal stenosis.

    Science.gov (United States)

    Nogales, Óscar; Clemente, Ana; Caballero-Marcos, Aránzazu; García-Lledó, Javier; Pérez-Carazo, Leticia; Merino, Beatriz; López-Ibáñez, María; Pérez Valderas, María Dolores; Bañares, Rafael; González-Asanza, Cecilia

    2017-07-01

    Benign esophageal strictures are relatively frequent and can severely affect the quality of life of a patient. Stenting has been proposed for the treatment of refractory cases. Lesions affecting the cervical esophagus are more difficult to treat, and the placement of stents in this location has traditionally been restricted due to potential adverse events. The aim of this study was to describe the efficacy and safety of endoscopic stenting in the management of refractory benign cervical esophageal strictures (RBCES) in a single-center cohort study. We analyzed 12 patients with RBCES (Kochman's criteria) and severe dysphagia. We recorded previous endoscopic treatments, stricture characteristics and demographic data. The two types of stents used were fully covered self-expandable metallic stents (FCSEMS) and uncovered biodegradable stents (BDS). FCSEMS were removed eight weeks after placement, and BDS were followed-up until degradation. We assessed technical and clinical success, rate of stricture recurrence and adverse events. The mean age of participants was 64 years (range 30-85). A total of 23 stents (13 FCSEMS and 10 BDS) were placed in 12 patients (median 1.92, range 1-4). The technical success rate was 96% (22/23 stents). Eight patients (66.6%) maintained adequate oral intake at the end of follow-up (median 33.3 months, range 3-84 months). Migration was recorded in 7/23 stents (30.4%) and epithelial hyperplasia in 4/23 stents (17.4%). No severe adverse events were noted. All patients complained of minor cervical pain after placement that was well controlled with mild analgesia. Endoscopic stent therapy seems to be effective and safe in the management of RBCES.

  13. 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)

  14. 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

  15. Stent fabric fatigue of grafts supported by Z-stents versus ringed stents: an in vitro buckling test.

    Science.gov (United States)

    Lin, Jing; Wang, Lu; Guidoin, Robert; Nutley, Mark; Song, Ge; Zhang, Ze; Du, Jia; Douville, Yvan

    2014-03-01

    Stent-grafts externally fitted with a Z-shaped stents were compared to devices fitted with ringed stents in an in vitro oscillating fatigue machine at 200 cycles per minute and a pressure of 360 mmHg for scheduled durations of up to 1 week. The devices fitted with Z-stents showed a considerably lower endurance limit to buckling compared to the controls. The contact between the apexes of adjacent Z-stents resulted in significant damage to the textile scaffolds and polyester fibers due to the sharp angle of the Z-stents. The ringed stents did not cause any fraying in the textile scaffolds.

  16. Electrophoretic deposition (EPD) of hydrous ruthenium oxides with PTFE and their supercapacitor performances

    International Nuclear Information System (INIS)

    Jang, Jong H.; Machida, Kenji; Kim, Yuri; Naoi, Katsuhiko

    2006-01-01

    The effect of PTFE addition was investigated for the electrophoretic deposition (EPD) of hydrous ruthenium oxide electrodes. Mechanical stability of electrode layers, together with deposition yield, was enhanced by using hydrous ruthenium oxide/PTFE dispersions. High supercapacitor performance was obtained for the electrodes prepared with 2% PTFE and 10% water. When PTFE content was higher, the rate capability became poor with low electronic conductivity; higher water content than 10% resulted in non-uniform depositions with poor cycleability and power capability. When electrodes were heat treated at 200 deg. C for 10 h, the specific energy was as high as 17.6 Wh/kg based on single electrode (at 200 W/kg); while utilizable energy was lower with heat treatment time of 1 and 50 h, due to the high resistance and gradual crystallization, respectively. With PTFE addition and heat treatment at 200 deg. C for 10 h, the specific capacitance was increased by 31% (460 → 599 F/g at ca. 0.6 mg/cm 2 ) at 10 mV/s, and the deposition weight was increased up to 1.7 mg/cm 2 with initial capacitance of 350 F/g

  17. Thermal and radiation process for nano-/micro-fabrication of crosslinked PTFE

    International Nuclear Information System (INIS)

    Kobayashi, Akinobu; Oshima, Akihiro; Okubo, Satoshi; Tsubokura, Hidehiro; Takahashi, Tomohiro; Oyama, Tomoko Gowa; Tagawa, Seiichi; Washio, Masakazu

    2013-01-01

    Nano-/micro-fabrication process of crosslinked poly(tetrafluoroethylene) (RX-PTFE) is proposed as a novel method using combined process which is thermal and radiation process for fabrication of RX-PTFE (TRaf process). Nano- and micro-scale patterns of silicon wafers fabricated by EB lithography were used as the molds for TRaf process. Poly(tetrafluoroethylene) (PTFE) dispersion was dropped on the fabricated molds, and then PTFE was crosslinked with doses from 105 kGy to 1500 kGy in its molten state at 340 °C in nitrogen atmosphere. The obtained nano- and micro-structures by TRaf process were compared with those by the conventional thermal fabrication process. Average surface roughness (R a ) of obtained structures was evaluated with atomic force microscope (AFM) and scanning electron microscope (SEM). R a of obtained structures with the crosslinking dose of 600 kGy showed less than 1.2 nm. The fine nano-/micro-structures of crosslinked PTFE were successfully obtained by TRaf process

  18. Comparison of FLIXENE™ and standard PTFE arteriovenous graft for early haemodialysis.

    Science.gov (United States)

    Chiang, Nathaniel; Hulme, Katherine Ria; Haggart, Paul Charles; Vasudevan, Thodur

    2014-01-01

    The purpose is to compare the outcomes of FLIXENE™ arteriovenous graft (AVG) to standard polytetrafluoroethylene (PTFE) AVG for early haemodialysis. This is a prospective observational study of all AVGs placed over a 40-month period between 2008 and 2011 at our vascular unit. Primary outcome was to examine early cannulation rates for FLIXENE™. Secondary outcomes included patency rates, usability of grafts, complications in particular infections, interventions and death in comparison to standard PTFE grafts. Forty-five FLIXENE™ and 19 standard PTFE AVGs were placed in the study period; 89% of FLIXENE™ grafts were used for dialysis, with 78% cannulated within 3 days. At 18 months, primary patency (FLIXENE™ 34% vs standard PTFE 24%), primary assisted patency (35% vs 36%) and secondary patency rate (51% vs 48%) were not statistically different; 20.2% of FLIXENE™ grafts were infected at 18 months requiring explantation compared with 40.3% of standard PTFE grafts (p=0.14). FLIXENE™ can be cannulated for dialysis within 3 days. It has similar patency and complication rates as other prosthetic grafts in the market. In patients who have no access and require urgent dialysis, FLIXENE™ is a viable option.

  19. Biocompatibility assessment of porous chitosan-Nafion and chitosan-PTFE composites in vivo.

    Science.gov (United States)

    Liu, Bo-Ji; Ma, Li-Nan; Su, Juan; Jing, Wei-Wei; Wei, Min-Jie; Sha, Xian-Zheng

    2014-06-01

    Chitosan (CS) is widely used as a scaffold material in tissue engineering. The objective of this study was to test whether porous chitosan membrane (PCSM) coating for Nafion used in implantable sensor reduced fibrous capsule (FC) density and promoted superior vascularization compared with PCSM coating for polytetrafluoroethylene (PTFE). PCSM was fabricated with solvent casting/particulate leaching method using silica gel as porogen and characterized in vitro. Then, PCSM-Nafion and PCSM-PTFE composites were assembled with hydrated PCSM and implanted subcutaneously in rats. The histological analysis was performed in comparison with Nafion and PTFE. Implants were explanted 35, 65, and 100 days after the implantation. Histological assessments indicated that both composites achieved presumed effects of porous coatings on decreasing collagen deposition and promoting angiogenesis. PCSM-PTFE exerted higher collagen deposition by area ratio, both within and outside, compared with that of PCSM-Nafion. Angiogenesis within and outside the PCSM-Nafion both increased over time, but that of the PCSM-PTFE within decreased. Copyright © 2013 Wiley Periodicals, Inc.

  20. Production of porous PTFE-Ag composite thin films by pulsed laser deposition

    International Nuclear Information System (INIS)

    Kecskeméti, Gabriella; Hopp, Béla; Smausz, Tomi; Tóth, Zsolt; Szabó, Gábor

    2012-01-01

    The suitability of pulsed laser deposition technique for preparation of polytetrafluoroethylene (PTFE) and silver (Ag) composite thin films was demonstrated. Disk-shaped targets combined from silver and Teflon with various percentages were ablated with pulses of an ArF excimer laser. The chemical composition of the deposited layers was estimated based on deposition rates determined for the pure PTFE and Ag films. EDX and SEM analyses using secondary electron and backscattered electron images proved that the morphology of the layers is determined by the PTFE which is the main constituent and it is transferred mostly in form of grains and clusters forming a sponge-like structure with high specific surface. The Ag content is distributed over the surface of the PTFE structure. Contact angle measurements showed that with increasing the amount of Ag in the deposited layers the surface significantly enhanced the wetting properties. Conductivity experiments demonstrated that when the average silver content of the layers was increased from 0.16 to 3.28 wt% the resistance of our PTFE-Ag composite films decreased with about three orders of magnitudes (from ∼10 MΩ to ∼10 kΩ). The properties of these films suggest as being a good candidate for future electrochemical sensor applications.

  1. Adhesion and removal kinetics of Bacillus cereus biofilms on Ni-PTFE modified stainless steel.

    Science.gov (United States)

    Huang, Kang; McLandsborough, Lynne A; Goddard, Julie M

    2016-01-01

    Biofilm control remains a challenge to food safety. A well-studied non-fouling coating involves codeposition of polytetrafluoroethylene (PTFE) during electroless plating. This coating has been repo