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  1. Thrombogenicity and Reoperation of the St. Jude Medical Silzone (R) valve : A comparison with the conventional St. Jude medical valve

    NARCIS (Netherlands)

    Stalenhoef, JE; Mellema, EC; Veeger, NJGM; Ebels, T

    2003-01-01

    Background and aim of the study: The St. Jude Medical Silzone(R) valve was withdrawn from the market after an interim analysis of the AVERT study revealed a 2.76% incidence of paravalvar leakage leading to valve re-replacement, compared with only 1.02% in the control group. Additionally, an increase

  2. Effect of heart rate on the hemodynamics of bileaflet mechanical heart valves' prostheses (St. Jude Medical) in the aortic position and in the opening phase: A computational study.

    Science.gov (United States)

    Jahandardoost, Mehdi; Fradet, Guy; Mohammadi, Hadi

    2016-03-01

    To date, to the best of the authors' knowledge, in almost all of the studies performed around the hemodynamics of bileaflet mechanical heart valves, a heart rate of 70-72 beats/min has been considered. In fact, the heart rate of ~72 beats/min does not represent the entire normal physiological conditions under which the aortic or prosthetic valves function. The heart rates of 120 or 50 beats/min may lead to hemodynamic complications, such as plaque formation and/or thromboembolism in patients. In this study, the hemodynamic performance of the bileaflet mechanical heart valves in a wide range of normal and physiological heart rates, that is, 60-150 beats/min, was studied in the opening phase. The model considered in this study was a St. Jude Medical bileaflet mechanical heart valve with the inner diameter of 27 mm in the aortic position. The hemodynamics of the native valve and the St. Jude Medical valve were studied in a variety of heart rates in the opening phase and the results were carefully compared. The results indicate that peak values of the velocity profile downstream of the valve increase as heart rate increases, as well as the location of the maximum velocity changes with heart rate in the St. Jude Medical valve model. Also, the maximum values of shear stress and wall shear stresses downstream of the valve are proportional to heart rate in both models. Interestingly, the maximum shear stress and wall shear stress values in both models are in the same range when heart rate is valve model when heart rate is >90 beats/min (up to ~40% growth compared to that of the native valve). The findings of this study may be of importance in the hemodynamic performance of bileaflet mechanical heart valves. They may also play an important role in design improvement of conventional prosthetic heart valves and the design of the next generation of prosthetic valves, such as percutaneous valves.

  3. Influence of St. Jude medical valve in patients with aortic stenosis and small aortic annulus on cardiac function and late survival result.

    Science.gov (United States)

    Natsuaki, Masafumi; Itoh, Tsuyoshi; Okazaki, Yukio; Takarabe, Kyoumi; Furukawa, Koujirou; Rikitake, Kazuhisa; Ohtubo, Satoshi

    2002-10-01

    This clinical study analyzes our experience of postoperative cardiac function and long-term survival rate in patients with aortic stenosis and small-size St. Jude Medical (SJM) valve. Sixty-eight patients who underwent aortic valve replacement by SJM valve were divided into two groups by preoperative aortic annulus diameter. Group 1 consisted of 44 patients with small aortic annulus and small-size SJM valve (19 mm or 21 mm). In Group 1, small SJM standard valves were implanted in 16 patients, and small SJM Hemodynamic Plus (HP) valves were implanted in 28 patients. Group 2 consisted of 24 patients with large-size SJM standard valve (23 mm or larger). Preoperative left ventricular mass index, left ventricular dimension, the dimension of ascending aorta, and body surface area were significantly smaller in Group 1 than in Group 2. Average age at surgery was older in Group 1 than in Group 2. Effective orifice area index of the SJM valve measured by the manufacturer's data was smaller in Group 1 than in Group 2. Postoperative left ventricular mass indexes of Group 1 (standard valve or HP valve) and Group 2 significantly decreased in comparison with the preoperative mass indexes. Postoperative left ventricular ejection fraction and the peak ejection rate of Group 1 were not different from those of Group 2. The 10 year survival rate of Group 1 was 79%, and the rate of Group 2 was 77%. At 10 years after surgery, freedom from valve-related complication of Group 1 was 80%, and freedom from complication of Group 2 was 81%. Our results demonstrated that small-size SJM valve afforded satisfactory long-term survival rate and valve-related event-free rate for elderly patients with small body surface area and small aortic annulus.

  4. Mid-term results of small-sized St. Jude Medical Regent prosthetic valves (21 mm or less) for small aortic annulus.

    Science.gov (United States)

    Mizoguchi, Hiroki; Sakaki, Masayuki; Inoue, Kazushige; Iwata, Takashi; Tei, Keikou; Miura, Takuya

    2013-11-01

    Prosthesis-patient mismatch (PPM) is always of concern when performing aortic valve replacement (AVR) in patients with a small aortic annulus. Although bioprosthetic AVR is preferred in patients older than 65 years, we have experienced cases in elderly patients with a small aortic annulus whereby we could not implant small-sized bioprosthetic valves. We have implanted St. Jude Medical Regent (SJMR) mechanical valves (St. Jude Medical, St. Paul, MN, USA) as necessary, even in elderly patients with no aortic annulus enlargement. We investigated our experiences of AVR with SJMR mechanical valves of 21 mm or less in size. Between January 2006 and December 2009, 40 patients underwent AVR with SJMR mechanical valves ≤21 mm in size: 9 patients received 21-mm valves, 19 received 19-mm valves, and 12 received 17-mm valves. The mean age was 65.9 ± 9.5 years, and 25 patients (62.5 %) were 65 years or older. We evaluated the clinical outcome and the echocardiographic data for each valve size. There was no operative or hospital mortality. The mean duration of clinical follow-up was 31.2 ± 17.6 months. During follow-up, there were no hospitalizations due to heart failure. The cumulative valve-related event-free survival was 93 % at 33 months, and the cumulative hemorrhagic event-free survival was 93 % at 33 months and 84 % at 43 months, using the Kaplan-Meier method. At follow-up, the mean values of the measured effective orifice area (EOA) for the 21-, 19-, and 17-mm prostheses were 2.00 ± 0.22, 1.74 ± 0.37, and 1.25 ± 0.26 cm(2), and the mean measured EOA index (EOAI) were 1.17 ± 0.12, 1.11 ± 0.21 and 0.90 ± 0.22 cm(2)/m(2), respectively. A PPM (EOAI ≤0.85) was documented in 5 patients, all of whom had received a 17-mm SJMR valve. AVR with SJMR valves of 21 mm or less in size appears to show satisfactory clinical and hemodynamic results.

  5. Evaluation of 17-mm St. Jude Medical Regent prosthetic aortic heart valves by rest and dobutamine stress echocardiography

    Directory of Open Access Journals (Sweden)

    Minardi Giovanni

    2006-09-01

    Full Text Available Abstract Background The prosthesis used for aortic valve replacement in patients with small aortic root can be too small in relation to body size, thus showing high transvalvular gradients at rest and/or under stress conditions. This study was carried out to evaluate rest and Dobutamine stress echocardiography (DSE hemodynamic response of 17-mm St. Jude Medical Regent (SJMR-17 mm in relatively aged patients at mean 24 months follow-up. Methods and results The study population consisted of 19 patients (2 men, 17 women, mean age 69.2 ± 7.3 years. All patients underwent rest Doppler echocardiography before and after surgery and basal and DSE at follow up (infused at rate of 5 micrg/Kg/min and increased by 5 microg/Kg/min at 5 min intervals up to 40 microg/Kg/min. The following parameters were evaluated at rest and/or under DSE: heart rate (HR, ejection fraction (EF, cardiac output (CO, peak and mean velocity and pressure gradients (MxV, MnV, MxPG, MnPG, effective orifice area (EOA, indexed EOA (EOAi, left ventricular mass (LVM, indexed LVM (LVMi, Velocity Time Integral at left ventricular outflow tract (VTI LVOT and transvalvular (Aortic VTI, Doppler velocity index (DVI. At rest MxPG and MnPG were 29.2 ± 7.1 and 16.6 ± 5.8mmHg, respectively; EOA and EOAi resulted 1.14 ± 0.3 cm2 and 0.76 ± 0.2 cm2/m2; DVI was normal (0.50 ± 0.1. At follow-up LVM and LVMi decreased significantly from pre-operative value of 258 ± 43g and 157.4 ± 27.7g/m2 to 191 ± 23.8g and 114.5 ± 10.6g/m2, respectively. DSE increased significantly HR, CO, EF, MxGP (up to 83.4 ± 2 1.9mmHg, MnPG (up to 43.2 ± 12.7mmHg. EOA, EOAi, DVI increased insignificantly (from baseline up to 1.2 ± 0.4 cm2, 0.75 ± 0.3cm2/m2 and 0.48 ± 0.1 respectively. Two patients developed significant intraventricular gradients. Conclusion These data show that SJMR 17-mm prostheses can be safely implanted in aortic position in relatively aged patients, offering a satisfactory hemodynamic

  6. Effect of hinge gap width of a St. Jude medical bileaflet mechanical heart valve on blood damage potential--an in vitro micro particle image velocimetry study.

    Science.gov (United States)

    Jun, Brian H; Saikrishnan, Neelakantan; Arjunon, Sivakkumar; Yun, B Min; Yoganathan, Ajit P

    2014-09-01

    The hinge regions of the bileaflet mechanical heart valve (BMHV) can cause blood element damage due to nonphysiological shear stress levels and regions of flow stasis. Recently, a micro particle image velocimetry (μPIV) system was developed to study whole flow fields within BMHV hinge regions with enhanced spatial resolution under steady leakage flow conditions. However, global velocity maps under pulsatile conditions are still necessary to fully understand the blood damage potential of these valves. The current study hypothesized that the hinge gap width will affect flow fields in the hinge region. Accordingly, the blood damage potential of three St. Jude Medical (SJM) BMHVs with different hinge gap widths was investigated under pulsatile flow conditions, using a μPIV system. The results demonstrated that the hinge gap width had a significant influence during the leakage flow phase in terms of washout and shear stress characteristics. During the leakage flow, the largest hinge gap generated the highest Reynolds shear stress (RSS) magnitudes (~1000 N/m²) among the three valves at the ventricular side of the hinge. At this location, all three valves indicated viscous shear stresses (VSS) greater than 30 N/m². The smallest hinge gap exhibited the lowest level of shear stress values, but had the poorest washout flow characteristics among the three valves, demonstrating propensity for flow stasis and associated activated platelet accumulation potential. The results from this study indicate that the hinge is a critical component of the BMHV design, which needs to be optimized to find the appropriate balance between reduction in fluid shear stresses and enhanced washout during leakage flow, to ensure minimal thrombotic complications.

  7. Micro particle image velocimetry measurements of steady diastolic leakage flow in the hinge of a St. Jude Medical® regent™ mechanical heart valve.

    Science.gov (United States)

    Jun, Brian H; Saikrishnan, Neelakantan; Yoganathan, Ajit P

    2014-03-01

    A number of clinical, in vitro and computational studies have shown the potential for thromboembolic complications in bileaflet mechanical heart valves (BMHV), primarily due to the complex and unsteady flows in the valve hinges. These studies have focused on quantitative and qualitative parameters such as velocity magnitude, turbulent shear stresses, vortex formation, and platelet activation to identify potential for blood damage. However, experimental characterization of the whole flow fields within the valve hinges has not yet been conducted. This information can be utilized to investigate instantaneous damage to blood elements and also to validate numerical studies focusing on the hinge's complex fluid dynamics. The objective of this study was therefore to develop a high-resolution imaging system to characterize the flow fields and global velocity maps in a BMHV hinge. In this study, the steady leakage hinge flow fields representing the diastolic phase during the cardiac cycle in a 23 mm St. Jude Medical regent BMHV in the aortic position were characterized using a two-dimensional micro particle image velocimetry system. Diastolic flow was simulated by imposing a static pressure head on the aortic side. Under these conditions, a reverse flow jet from the aortic to the ventricular side was observed with velocities in the range of 1.47-3.24 m/s, whereas low flow regions were observed on the ventricular side of the hinge with viscous shear stress magnitude up to 60 N/m². High velocities and viscous shearing may be associated with platelet activation and hemolysis, while low flow zones can cause thrombosis due to increased residence time in the hinge. Overall, this study provides a high spatial resolution experimental technique to map the fluid velocity in the BMHV hinge, which can be extended to investigate micron-scale flow domains in various prosthetic devices under different hemodynamic conditions.

  8. Mid-long-term Clinical Results and Hemodynamic Evaluation of Aortic Valve Replacement with 17 mm St. Jude Medical Regent Valve%17 mm St.Jude Regent瓣术后中远期临床效果和在体血流动力学评价

    Institute of Scientific and Technical Information of China (English)

    刘勇; 张尔永; 方智; 古君; 钱宏

    2013-01-01

    Objective To investigate the mid-long-term clinical results of aortic valve replacement with 17 mm St. Jude medical regent valve with hemodynamic evaluation including the measurement of effective orifice area, the occurrence of prosthesis-patient mismatch (PPM) and its affect on heart function. Methods There were 44 patients accepted aortic valve replacement with 17 mm St. Jude medical regent valve because of small aortic annulus. Before the operation and during the postoperative follow-up, color doppler echocardiography was used to measure the hemodynamic parameters, such as left ventricular mass (LVmass), effective orifice area (EOA) and effective orifice area index (EOAI), etc.. Results Transthoracic echocardiographic data were obtained from 39 of 44 patients (88. 6%)at 12-55 months after surgery. One (2. 27%) died of heart failure in 1 year. According to the current standard of PPM (EOAI≤0. 85 cm2/m2) , 33 cases (82. 1%) had PPM, 13 cases (30. 8%) had severe PPM with an EOAI ≤0. 65 cm2/m2. After the operation, there were significant decreases in LVAo-PG (19 ± 8) mmHg and left ventricular mass index (LVmass I ) (86. 6 ± 23. 3) g/m2(P<0. 05). The assessment for physical capacity according to NYHA classification: 41 patients improved to class II or better and 2 patients improved to class Ⅲ (P<0. 05). Conclusion The patients with small aortic annulus may obtain satisfactory clinical results after AVR with 17 mm St. Jude medical regent valve, PPM seems not affect the mid-long-term results.%目的 观察17 mm St.Jude Regent机械瓣置入人体后中远期临床效果,测量其有效瓣口面积,评价是否发生瓣膜-患者不匹配(prosthesis-patient mismatch,PPM)现象,并探索PPM现象对术后患者心功能的影响.方法 44例心脏瓣膜病患者接受二尖瓣及主动脉瓣置换术,所有患者因主动脉瓣环小而置入17 mm St.Jude Regent机械瓣.对该组患者进行随访研究,分别于术前及术后12~55月,运用心

  9. 中度瓣膜-患者不匹配对17 mm St.Jude Medical Regent主动脉瓣置换术后中期临床效果的影响%The impact of moderate prosthesis-patient mismatch on midterm outcomes after aortic valve replacement with 17 mm St.Jude Medical Regent valve

    Institute of Scientific and Technical Information of China (English)

    胡佳; 钱宏; 李娅姣; 古君; 方智; 刘勇; 蒙炜; 张尔永

    2014-01-01

    目的 观察术后早期中度瓣膜-患者不匹配现象(prosthesis-patient mismatch,PPM)对应用17 mm St.Jude Medical Regent(SJMR)行主动脉瓣置换术后患者中远期临床效果的影响,并探讨患者个体因素与PPM影响效果的关系.方法 我们对106例应用17 mm SJMR行主动脉瓣置换术的患者进行随访,于术前、出院时及术后29~ 74个月,平均(48.6±11.9)个月,评估患者术后临床指标和Regent瓣膜在体血流动力学参数变化.结果 围手术期死亡比例2.8%,术后1、3、5年免于心脏不良事件相关死亡比例分别为98.1%、95.9%、88.2%.其中45例(43.7%)患者在术后院内末次超声心动图评估发现合并中度PPM.随访期间,患者NYHA心功能分级、主动脉瓣跨瓣压差及左心室质量指数均较术前明显改善,合并中度PPM患者与非PPM患者在各临床指标与血流动力学参数之间并无明显差异.但在术前左心功能受损的患者中(左心室射血分数<0.50),中度PPM会显著增加此亚组患者中远期死亡比例(HR 1.46,P=0.02).多因素回归分析发现,糖尿病与左心室射血分数<0.35是导致全组患者术后中远期死亡比例增加的独立危险因素.结论 17 mm SJMR主动脉瓣置换术后早期出现的中度PPM与左心功能受损患者术后中远期死亡比例增加密切相关.合理选择小主动脉瓣环患者接受17 mm SJMR瓣膜的置入能取得满意的中远期临床效果.%Objective The study was designed to evaluate the effects of moderate prosthesis-patient mismatch(PPM) on midterm outcomes after aortic valve replacement(AVR) with the 17 mm St.Jude Medical Regent valve in a large series of patients,and to determine if these effects are modulated by patient' s confounding variables.Methods Methods One-hundred and six patients with and without moderate PPM after implantation of a 17 mm Regent valve at aortic position were included.Both clinical and echocardiographic assessments were performed

  10. Echocardiographic and phonocardiographic assessment of the St. Jude cardiac valve prosthesis.

    Science.gov (United States)

    DePace, N L; Kotler, M N; Mintz, G S; Lichtenberg, R; Goel, I P; Segal, B L

    1981-09-01

    Forty-three consecutive patients with a St. Jude mitral, aortic, or combined prosthesis were studied by simultaneous phonocardiography and echocardiography. Twenty-eight patients had a mitral prosthesis, 20 an aortic prosthesis, and five had both. No opening click was recorded in any patient; however, a loud aortic or mitral closing click was recorded in all 43 patients. In patients with St. Jude mitral valve prosthesis, an echo-free space separated the two leaflets during diastole; seven of these also had a mid-diastolic closing and late diastolic reopening motion; two of the seven had an associated closing mid-diastolic click. A mid-diastolic rumble was recorded in six of 28 patients with St. Jude mitral valve prosthesis. In patients with a St. Jude aortic valve prosthesis, left atrium leaflet motion was recorded in 17 of 20 patients and was indistinguishable in appearance from echocardiograms obtained with various eccentric monocusp valves. In addition, we report one case of malfunction of a St. Jude mitral valve and one case of a paravalvular leak diagnosed by echophonocardiography. We concluded that the St. Jude cardiac prosthesis has variable normal phonocardiographic-echocardiographic patterns. Knowledge of these variable patterns is important in assessing patients with suspected malfunction of a St. Jude cardiac prosthesis.

  11. Hemodynamic function of the standard St. Jude bileaflet disc valve has no clinical impact 10 years after aortic valve replacement

    DEFF Research Database (Denmark)

    Lund, Ole; Dorup, Inge; Emmertsen, Kristian

    2005-01-01

    OBJECTIVES: Size mismatch and impaired left ventricular function have been shown to determine the hemodynamic function of the standard St. Jude bileaflet disc valve early after aortic valve replacement (AVR). We aimed to analyse St. Jude valve hemodynamic function and its clinical impact in the s......OBJECTIVES: Size mismatch and impaired left ventricular function have been shown to determine the hemodynamic function of the standard St. Jude bileaflet disc valve early after aortic valve replacement (AVR). We aimed to analyse St. Jude valve hemodynamic function and its clinical impact...... in the survivors of a prospective series 10 years after AVR for aortic stenosis. DESIGN: Forty-three survivors aged 32-90 years from a prospective series attended a follow-up study with Doppler echo and radionuclide cardiography 10 years after AVR for aortic stenosis. Six patients with significant left sided valve......Hg. In a multilinear regression analysis GOA indexed for LVEDD, hypertension, and LVEF were independently related to peak gradient. CONCLUSION: High gradients of the standard St. Jude bileaflet disc valve 10 years after AVR was primarily related to systemic hypertension and mismatch between valve and left ventricular...

  12. Substituição valvar isolada com próteses metálicas St. Jude Medical em posição aórtica ou mitral: seguimento de médio prazo Sustitución valvular aislada con prótesis metálicas St. Jude Medical en posición aórtica o mitral: seguimiento de medio plazo Isolated mitral and aortic valve replacement with the St. Jude Medical valve: a midterm follow-up

    Directory of Open Access Journals (Sweden)

    Alfredo José Rodrigues

    2009-09-01

    a la sustitución de la válvula mitral o aórtica por prótesis valvular mecánica St. Jude. MÉTODOS: Se analizó retrospectivamente la evolución de los pacientes operados entre enero de 1995 y diciembre de 2003 y seguidos hasta diciembre de 2006. RESULTADOS: Un total de 168 pacientes recibió prótesis valvular mitral y otros 117, aórtica. La edad promedio de ambos grupos fue de 45 años. Entre los mitrales, el 75% tenía hasta 55 años y el 65% era mujeres. Entre los aórticos, el 66% tenía hasta 55 años y el 69% era de varones. Teniendo en cuenta solamente las muertes relacionadas a las prótesis valvulares, la sobrevida fue del 85,6% para los mitrales y del 88,7% para los aórticos (p=0.698. Entre los mitrales, el 97% estaba libre de reoperación, y entre los aórticos el 99% (p=0,335 lo estaba. En cuanto a los eventos tromboembólicos, el porcentaje de pacientes libres fue del 82% entre los mitrales y del 98% entre los aórticos (p=0,049, y para los eventos hemorrágicos fue del 71% y el 86% respectivamente (0,579. En cuanto a la ocurrencia de endocarditis, el 98 % entre los mitrales y el 99% entre los aórticos estaba libre al final de 10 años (p=0.534. CONCLUSIÓN: Nuestra experiencia con prótesis metálicas St. Jude en una población predominantemente joven confirma el buen desempeño de esta prótesis, según otras experiencias publicadas.BACKGROUND: In our country, the biological valvular prostheses predominate, considering the difficulties related to anticoagulation, even in young patients, in spite of the need for repeated operations due to the degeneration of the bioprostheses. OBJECTIVES: To report our consecutive series of recipients of isolated St Jude Medical mechanical valve prosthesis in the mitral (MVR or aortic (AVR position. METHODS: Data from patients operated between January 1995 and December 2003 were revised in order to determine patient survival and prosthesis-related events up to December 2006. RESULTS: One hundred sixty eight

  13. Low standard oral anticoagulation therapy for Chinese patients with St.Jude mechanical heart valves

    Institute of Scientific and Technical Information of China (English)

    孙晓刚; 胡盛寿; 祁国奇; 周玉燕

    2003-01-01

    Objective To study the efficacy of the low standard oral anticoagulation therapy following St Jude Medical (SJM) valve implantation for Chinese patients.Methods Totally 805 patients with a mean age of 42.70±11.09 years, enrolled into this study. Among them, 230 underwent aortic valve replacements (AVR), 381 mitral valve replacements (MVR), 189 double valve replacements (DVR) and 5 tricuspid valve replacememts (TVR). All patients received postoperative oral anticoagulation therapy based on a low standard of international normalized ratio (INR, 2.0-2.5). Of the 805 patients, 710 were followed up for 0.25-13 years (a median, 4.15 years). Results Postoperatively, 17 adverse events occurred. Operative mortality was 2.11%. The most frequent cause of operative mortality was a low cardiac output. During follow-up, there were 47 anticoagulant-induced hemorrhages [1.59%/patient-year (pt-yr)], 10 cases of thromboembolism (0.34%/pt-yr), and 3 mechanical valve thromboses (0.19%/pt-yr). There were 44 late deaths and the linearized late mortality rates were 0.51%pt-yr. Estimates of actuarial survival for all patients at 5 and 10 years was 97.45% (0.70%) and 77.96% (17.44%), respectively.Conclusions A low target INR range of 2.0-2.5 is preferable for Chinese patients so as to reduce the severe bleeding complications in those with conventionally higher levels of INR. The long-term results were satisfactory in terms of the numbers of those who suffered thrombosis, embolism and bleeding.

  14. [Implantable loop recorder of the Confirm family (St. Jude Medical)].

    Science.gov (United States)

    Pujdak, Krzysztof

    2016-12-01

    St. Jude Medical produces the implantable loop recorder (ILR) Confirm AF DM2102 which offers subcutaneous electrodes on both sides of the device, a specific sensing algorithm and extensive storage capacity for up to 147 episodes. The reliability of detection of atrial fibrillation (AF) has been evaluated in the DETECT-AF study. The device is MR-conditional and allows patients an interrogation at home. The data are transferred to the follow-up centre via telephone by the patient activator, although this process is currently rather complex and slow. Therefore, remote monitoring of the Confirm AF DM2102 is rarely an option for elderly patients. St. Jude medical announced the introduction of a new, substantially smaller ILR using more modern technology by the end of 2016.

  15. In vivo left ventricular assist induced coagulation derangements. Comparison of Sarns-3M and St. Jude Medical circuits.

    Science.gov (United States)

    Curtis, J J; Wagner-Mann, C C; Mann, F A; Demmy, T L; Walls, J T; Schmaltz, R A

    1997-01-01

    An in vitro comparison of centrifugal pumping systems manufactured by Sarns-3M and St. Jude Medical revealed a difference in blood cell derangement. The purpose of this study was to compare in vivo the effects of 96 hr of left ventricular assist (LVA) on indexes of coagulopathy, hemolysis, and complement activation. Two groups of calves (each: n = 5) were instrumented with identical left atrial to thoracic aorta centrifugal pumping circuits using either Sarns-3M or St. Jude centrifugal pumps. Laboratory evaluations were performed pre-assist and at 1, 4, 24, 48, 72, and 96 hr during LVA. Platelet counts dropped significantly by 24 hr (Sarns-3M: 28%; St. Jude: 30%); no significant change in function was noted. Activated clotting time increased slightly (p > 0.05). Prothrombin time increased at 4 and 24 hr of LVA, returning to baseline by 96 hr (p Sarns-3M device never reached significance. No significant changes in lactate dehydrogenase or plasma free hemoglobin were detected. Complement fraction C5a rose by 1 hr of LVA (p Sarns-3M and St. Jude LVA caused coagulation derangement in calves, 2) neither pump demonstrated an advantage regarding coagulation and complement parameters, 3) hemolysis observed with the Sarns-3M pump in vitro was not evidenced in vivo, and 4) in vitro evidenced centrifugal pump differences may not be realized in vivo.

  16. Could Externalized St. Jude Medical Riata® Lead Be a Culture Medium of a Polymicrobial Endocarditis? A Clinical Case

    Directory of Open Access Journals (Sweden)

    Zefferino Palamà

    2017-01-01

    Full Text Available We report the case of a man affected by polymicrobial endocarditis developed on a St. Jude Medical Riata lead with a malfunction because of the outsourcing of conductors. The patient was treated with antibiotic targeted therapy and showed different bacteria at the blood cultures and then underwent transvenous leads extraction. Vegetations were highlighted on the caval, atrial, and ventricular tracts of the Riata lead, but the cultures were all negative. The externalization of Riata lead may cause the malfunction but it could also promote bacterial colonies and vegetations. In conclusion, looking for early signs of infection is mandatory during Riata leads follow-up checks.

  17. A Spiritual Victor in Jude the Obscure——Comparing Jude with Two Heroines%A Spiritual Victor in Jude the Obscure-Comparing Jude with Two Heroines

    Institute of Scientific and Technical Information of China (English)

    冯冬惠

    2007-01-01

    Jude is a final victor in spirit.Jude's leaving Arabella,a conventional-orientation representive and then following Sue's unconventional pursuit are greatly valued in Hardy's novel-Jude the Obscure.Furthermore,Jude's constancy in unconventional belief is valuable,contrasting with Sue's final regression to convention.Compared with Arabella and Jude's spiritual quality,Jude proves a victor.

  18. MECHANICAL HEART-VALVE PROSTHESES - SOUND LEVEL AND RELATED COMPLAINTS

    NARCIS (Netherlands)

    LAURENS, RRP; WIT, HP; EBELS, T

    1992-01-01

    In a randomised study, we investigated the sound production of mechanical heart valve prostheses and the complaints related to this sound. The CarboMedics, Bjork-Shiley monostrut and StJude Medical prostheses were compared. A-weighted levels of the pulse-like sound produced by the prosthesis were me

  19. On the Causes of Jude's Tragedy in Jude the Obscure

    Institute of Scientific and Technical Information of China (English)

    张杰

    2015-01-01

    Thomas Hardy's Jude the Obscure is a tragic novel, which shows the fight between flesh and spirit. From which, we can appreciate connotation of the character and environment novels and feel the Victorian period's social factors. This thesis aims at analyzing the real causes of Jude's tragedy from the social institution and his personal limitation hid in the tragic appearance.

  20. Hydrodynamic Performance of the Medtronic CoreValve and the Edwards SAPIEN XT Transcatheter Heart Valve in Surgical Bioprostheses: An In Vitro Valve-in-Valve Model.

    Science.gov (United States)

    Sedaghat, Alexander; Sinning, Jan-Malte; Utzenrath, Marc; Ghalati, Pejman Farhadi; Schmitz, Christoph; Werner, Nikos; Nickenig, Georg; Grube, Eberhard; Ensminger, Stephan; Steinseifer, Ulrich; Kuetting, Maximilian

    2016-01-01

    Valve-in-valve transcatheter aortic valve replacement (TAVR) is becoming a valuable option with promising clinical results in failed bioprosthetic heart valves. Sizing recommendations are based on size compatibility rather than on broad clinical data, in vitro measurements, or biomechanical evidence. The hemodynamic performance of transcatheter heart valves within degenerated surgical heart valves is unknown. We evaluated the in vitro hydrodynamic performance of two commercially available transcatheter heart valves (Medtronic CoreValve [Medtronic, Minneapolis, MN] and Edwards SAPIEN XT [Edwards Lifesciences, Irvine, CA]) in two different bioprosthetic aortic valves (Edwards Perimount [Edwards Lifesciences] and St. Jude Trifecta [St. Jude Medical, St. Paul, MN]). Within the Edwards Perimount (23 mm) prosthesis, pressure gradients were higher for the SAPIEN XT compared with the CoreValve (11.2 ± 0.1 mm Hg versus 10.1 ± 0.1 mm Hg, p < 0.01), whereas effective orifice area (1.99 ± 0.01 cm(2) versus 1.80 ± 0.01 cm(2), p < 0.01) and total paravalvular leakage (9.0% ± 1.0% versus 5.4% ± 1.3%, p < 0.01) were increased when using the CoreValve. Similarly, measurements in the St. Jude Trifecta revealed higher transvalvular pressure gradients (13.0 ± 0.2 mm Hg versus 10.9 ± 0.3 mm Hg, p < 0.01) and lower effective orifice area for the SAPIEN XT compared with the CoreValve. However, total relative regurgitation was higher with SAPIEN XT as compared with the CoreValve in St. Jude Trifecta prostheses (11.2% ± 1.4% versus 8.3% ± 0.9%, p < 0.01). Both transcatheter heart valve prostheses performed well in the described valve-in-valve settings. Hydrodynamic results were in line with the International Organization for Standardization standards for all configurations. The observed differences indicate a necessity for preclinical valve-in-valve tests in addition to clinical long-term data about longevity. Copyright © 2016 The Society of Thoracic Surgeons. Published by

  1. Churches in Jude the Obscure

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jing-jing

    2008-01-01

    In Hardy's novel,Jude the Obscure,many images and scenes relating to churches function to reveal the hero's,or the author's views towards Christian religion.This essay makes an analysis of the church architecture,church scenes and clerical characters in the novel.

  2. Transcatheter aortic valve implantation of the direct flow medical aortic valve with minimal or no contrast

    Energy Technology Data Exchange (ETDEWEB)

    Latib, Azeem, E-mail: alatib@gmail.com [Interventional Cardiology Unit, San Raffaele Scientific Institute and EMO-GVM Centro Cuore Columbus, Milan (Italy); Maisano, Francesco; Colombo, Antonio [Interventional Cardiology Unit, San Raffaele Scientific Institute and EMO-GVM Centro Cuore Columbus, Milan (Italy); Klugmann, Silvio [Azienda Ospedaliera Niguarda Ca Granda, Piazza Ospedale Maggiore 3, Milan (Italy); Low, Reginald; Smith, Thomas [University of California Davis, Davis, CA 95616 (United States); Davidson, Charles [Northwestern Memorial Hospital, Chicago, IL 60611 (United States); Harreld, John H. [Clinical Imaging Analytics, Guerneville, CA (United States); Bruschi, Giuseppe; DeMarco, Federico [Azienda Ospedaliera Niguarda Ca Granda, Piazza Ospedale Maggiore 3, Milan (Italy)

    2014-06-15

    The 18F Direct Flow Medical (DFM) THV has conformable sealing rings, which minimizes aortic regurgitation and permits full hemodynamic assessment of valve performance prior to permanent implantation. During the DISCOVER trial, three patients who were at risk for receiving contrast media, two due to severe CKD and one due to a recent hyperthyroid reaction to contrast, underwent DFM implantation under fluoroscopic and transesophageal guidance without aortography during either positioning or to confirm the final position. Valve positioning was based on the optimal angiographic projection as calculated by the pre-procedural multislice CT scan. Precise optimization of valve position was performed to minimize transvalve gradient and aortic regurgitation. Prior to final implantation, transvalve hemodynamics were assessed invasively and by TEE. The post-procedure mean gradients were 7, 10, 11 mm Hg. The final AVA by echo was 1.70, 1.40 and 1.68 cm{sup 2}. Total aortic regurgitation post-procedure was none or trace in all three patients. Total positioning and assessment of valve performance time was 4, 6, and 12 minutes. Contrast was only used to confirm successful percutaneous closure of the femoral access site. The total contrast dose was 5, 8, 12 cc. Baseline eGFR and creatinine was 28, 22, 74 mL/min/1.73 m{sup 2} and 2.35, 2.98, and 1.03 mg/dL, respectively. Renal function was unchanged post-procedure: eGFR = 25, 35, and 96 mL/min/1.73 m{sup 2} and creatinine = 2.58, 1.99, and 1.03 mg/dL, respectively. In conclusion, the DFM THV provides the ability to perform TAVI with minimal or no contrast. The precise and predictable implantation technique can be performed with fluoro and echo guidance.

  3. Recently patented transcatheter aortic valves in clinical trials.

    Science.gov (United States)

    Neragi-Miandoab, Siyamek; Skripochnik, Edvard; Salemi, Arash; Girardi, Leonard

    2013-12-01

    The most widely used heart valve worldwide is the Edwards Sapien, which currently has 60% of the worldwide transcatheter aortic valve implantation (TAVI) market. The CoreValve is next in line in popularity, encompassing 35% of the worldwide TAVI market. Although these two valves dominate the TAVI market, a number of newer transcatheter valves have been introduced and others are in early clinical evaluation. The new valves are designed to reduce catheter delivery diameter, improve ease of positioning and sealing, and facilitate repositioning or removal. The most recent transcatheter valves for transapical use include Acurate TA (Symetis), Engager (Medtronic), and JenaValve the Portico (St Jude), Sadra Lotus Medical (Boston Scientific), and the Direct Flow Medical. These new inventions may introduce more effective treatment options for high-risk patients with severe aortic stenosis. Improvements in transcatheter valves and the developing variability among them may allow for more tailored approaches with respect to patient's anatomy, while giving operators the opportunity to choose devices they feel more comfortable with. Moreover, introducing new devices to the market will create a competitive environment among producers that will reduce high prices and expand availability. The present review article includes a discussion of recent patents related to Transcatheter Aortic Valves.

  4. Fungal native pulmonary valve endocarditis: facing both medical and surgical challenges.

    Science.gov (United States)

    Bouabdallaoui, Nadia; Demondion, Pierre; Lebreton, Guillaume; Leprince, Pascal

    2017-01-01

    Fungal isolated native pulmonary valve endocarditis is extremely uncommon. Data are scarce and report high mortality and recurrence rates. Recommended management combines both medical and surgical approaches. We report herein a rare case of isolated pulmonary valve endocarditis caused by Candida albicans The patient did not display prior heart disease. Medical management was unsuccessful. Pulmonary valve replacement allowed rapid improvement. © The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  5. Application of Regent mechanical valve in patients with small aortic annulus: 3-year follow-up

    OpenAIRE

    Zhao Dong; Wang Chunsheng; Hong Tao; Pan Cuizhen; Guo Changfa

    2012-01-01

    Abstract Background Aortic valve replacement (AVR) with a small aortic annulus is always challenging for the cardiac surgeon. In this study, we sought to evaluate the midterm performance of implantation with a 17-mm or 19-mm St. Jude Medical Regent (SJM Regent) mechanical valve in retrospective consecutive cohort of patients with small aortic annulus (diameter ≤ 19 mm). Methods From January 2008 to April 2011, 40 patients (31 female, mean age = 47.2 ± 5.8 years) with small aortic annulus (≤19...

  6. Sue's Oppressed Sex in Jude the Obscure

    Institute of Scientific and Technical Information of China (English)

    陈娟

    2010-01-01

    Using ecofeminist literary criticism.the paper analyzes women's unjustified and dominated sex in Jude the Obscure.Sue,as a"New Woman"in the male-dominated society,is dominated and oppressed in sex.Sue's subordinated position illustrates Hardy's sympathy for Victorian women and his opposition to the unjustified domination of women.He advocates a harmonious relationship among people in the society.

  7. Bentall procedure 39 years after implantation of a Starr-Edwards Aortic Caged- Ball-Valve Prosthesis

    Directory of Open Access Journals (Sweden)

    Sohns Christian

    2010-03-01

    Full Text Available Abstract We report a case of a male patient who received an implantation of a Starr-Edwards-caged-ball-valve-prosthesis in 1967. The surgery and postoperative course were without complications and the patient recovered well after the operation. For the next four decades, the patient remained asymptomatic - no restrictions on his lifestyle and without any complications. In 2006, 39 years after the initial operation, we performed a Bentall-Procedure to treat an aortic ascendens aneurysm with diameters of 6.0 × 6.5 cm: we explanted the old Starr-Edwards-aortic-caged-ball-valve-prosthesis and replaced the ascending aorta with a 29 mm St.Jude Medical aortic-valve-composite-graft and re-implanted the coronary arteries. This case represents the longest time period between Starr-Edwards-caged-ball-valve-prothesis-implantation and Bentall-reoperation, thereby confirming the excellent durability of this valve.

  8. Effects of bileaflet mechanical heart valve orientation on coronary flow

    Science.gov (United States)

    Haya, Laura; Tavoularis, Stavros

    2015-11-01

    The aortic sinus is approximately tri-radially symmetric, but bileaflet mechanical heart valves (BMHVs), which are commonly used to replace diseased aortic valves, are bilaterally symmetric. This mismatch in symmetry suggests that the orientation in which a BMHV is implanted within the aortic sinus affects the flow characteristics downstream of it. This study examines the effect of BMHV orientation on the flow in the coronary arteries, which originate in the aortic sinus and supply the heart tissue with blood. Planar particle image velocimetry measurements were made past a BMHV mounted at the inlet of an anatomical aorta model under physiological flow conditions. The complex interactions between the valve jets, the sinus vortex and the flow in the right coronary artery were elucidated for three valve orientations. The coronary flow rate was directly affected by the size, orientation, and time evolution of the vortex in the sinus, all of which were sensitive to the valve's orientation. The total flow through the artery was highest when the valve was oriented with its axis of symmetry intersecting the artery's opening. The findings of this research may assist surgeons in choosing the best orientation for BMHV implantation. The bileaflet valve was donated by St. Jude Medical. Financial support was provided by the Natural Sciences and Engineering Research Council of Canada.

  9. A Study on the Characterization of Jude the Obscure

    Institute of Scientific and Technical Information of China (English)

    苏焕

    2007-01-01

    This paper is a brief study on the characterization of Jude the Obscure,and will be focus on the chief character Jude Fawley.This novel,first published in 1895,wasThomas Hardy's last and best literary success.There are six main characters in this novel:Jude Fawley,Susanna Bridehead,Arabella Donn,Richard Phillotson,Aunt Drusilla,Little Father Time(Little Jude).This analysis of the distinct depictions of the typical characters will be helpful to the understanding of the gap between the ideal life a man wishes to lead and the squalid existence he is fated to live in such social environment as Jude is confronted with.

  10. In vitro evaluation of valve hemodynamics in the pediatric pulmonary outflow tract

    Science.gov (United States)

    Schiavone, Nicole; Elkins, Chris; McElhinney, Doff; Eaton, John; Marsden, Alison

    2016-11-01

    Tetraology of Fallot (ToF) is a congenital heart disease that affects 1 in every 2500 newborns each year and requires surgical repair of the right ventricular outflow tract (RVOT) and subsequent placement of an artificial pulmonary valve. While a wide variety of artificial valves are available, essentially all of them become subject to degradation and dysfunction during the patient's lifetime, which leads to additional interventions. However, there is little understanding about the mechanical function of replacement pulmonary valves and no quantitative placement guidelines to ensure maximum failure-free lifetime. This work aims to experimentally assess the biomechanics of pulmonary valves in realistic RVOT geometries using magnetic resonance velocimetry (MRV), which can measure 3D, three-component phase-averaged velocity fields. The RVOT geometries are constructed using 3D printing, allowing for variation in crucial geometric parameters such as the radius of curvature of the main pulmonary artery (MPA) and the dilation of the artery downstream of the valve. A St. Jude Medical Epic valve is secured inside the RVOT geometry and can be interchanged, allowing for variation of the ratio between valve diameter and MPA diameter. This work will discuss the use of MRV to capture the flow structure in the RVOT and evaluate pulmonary valve performance under different conditions.

  11. Mitral Valve Replacement with Half-and-Half Technique for Recurrent Mitral Paravalvular Leakage.

    Science.gov (United States)

    Morisaki, Akimasa; Kato, Yasuyuki; Takahashi, Yosuke; Shibata, Toshihiko

    2015-05-01

    Reoperation for paravalvular leakage can cause recurrent paravalvular leakage through severe damage to the mitral annulus. Previously, mitral valve replacement using a half-and-half technique for extensive mitral annular calcification was reported; here, application of the technique to treat recurrent paravalvular leakage is described. A 78-year-old male with three prior mitral valve replacements developed recurrent paravalvular leakage, for which he had undergone his third mitral valve replacement at the age of 69 years. On this occasion, a mechanical valve with circumferential equine pericardial patch reinforcement of the annulus had been used. Five years later, the patient developed hemolytic anemia and congestive heart failure due to recurrent paravalvular leakage. Intraoperatively, broad dehiscence was seen between the prosthetic valve and mitral annulus at two sites, the anterior and posterior commissures, without infection. A fourth mitral valve replacement was performed with a St. Jude Medical valve, using a half-and-half technique. This entailed the use of non-everting mattress sutures on the anterior half of the annulus, and everting mattress sutures on the left atrial wall around the posterior half of the annulus. Extensive annular defects required reinforcement of the posterior mitral annulus with a bovine pericardial patch. Postoperative echocardiography showed no paravalvular leakage. The half-and-half technique may be useful in treating recurrent paravalvular leakage of the mitral valve.

  12. Experimental study on the effect of an artificial cardiac valve on the left ventricular flow

    Science.gov (United States)

    Wang, JiangSheng; Gao, Qi; Wei, RunJie; Wang, JinJun

    2017-09-01

    The use of artificial valves to replace diseased human heart valves is currently the main solution to address the malfunctioning of these valves. However, the effect of artificial valves on the ventricular flow still needs to be understood in flow physics. The left ventricular flow downstream of a St. Jude Medical (SJM) bileaflet mechanical heart valve (BMHV), which is a widely implanted mechanical bileaflet valve, is investigated with time-resolved particle image velocimetry in the current work. A tilting-disk valve is installed on the aortic orifice to guarantee unidirectional flow. Several post-processing tools are applied to provide combined analyses of the physics involved in the ventricular flow. The triple jet pattern that is closely related to the characteristics of the bileaflet valve is discussed in detail from both Eulerian and Lagrangian views. The effects of large-scale vortices on the transportation of blood are revealed by the combined analysis of the tracking of Lagrangian coherent structures, the Eulerian monitoring of the shear stresses, and virtual dye visualization. It is found that the utilization of the SJM BMHV complicates the ventricular flow and could reduce the efficiency of blood transportation. In addition, the kinematics of the bileaflets is presented to explore the effects of flow structures on their motion. These combined analyses could elucidate the properties of SJM BMHV. Furthermore, they could provide new insights into the understanding of other complex blood flows.

  13. Repeated mitral valve replacement in a patient with extensive annular calcification

    Directory of Open Access Journals (Sweden)

    Kitamura Tadashi

    2011-11-01

    Full Text Available Abstract Background Mitral valve replacement in the presence of severe annular calcification is a technical challenge. Case report A 47-year-old lady who had undergone mitral and aortic valve replacement for rheumatic disease 27 years before presented with dyspnea. At reoperation, extensive mitral annular calcification was hindering the disc motion of the Starr-Edwards mitral prosthesis. The old prosthesis was removed and a St Jude Medical mechanical valve was implanted after thorough annular debridement. Postoperatively the patient developed paravalvular leak and hemolytic anemia, subsequently undergoing reoperation three days later. The mitral valve was replaced with an Edwards MIRA valve, with a bulkier sewing cuff, after more aggressive annular debridement. Although initially there was no paravalvular leak, it recurred five days later. The patient also developed a small cerebral hemorrhage. As the paravalvular leak and hemolytic anemia gradually worsened, the patient underwent reoperation 14 days later. A Carpentier-Edwards bioprosthetic valve with equine pericardial patches, one to cover the debrided calcified annulus, another as a collar around the prosthesis, was used to eliminate paravalvular leak. At 7 years postoperatively the patient is doing well without any evidence of paravalvular leak or structural valve deterioration. Conclusion Mitral valve replacement using a bioprosthesis with equine pericardial patches was useful to overcome recurrent paravalvular leak due to severe mitral annular calcification.

  14. Unsteady fluid dynamics of several mechanical prosthetic heart valves using a two component laser Doppler anemometer system.

    Science.gov (United States)

    Akutsu, T; Modi, V J

    1997-10-01

    Five typical mechanical heart valves (Starr-Edwards, Björk-Shiley convexo-concave (c-c), Björk-Shiley monostrut, Bicer-Val, and St. Jude Medical) were tested in the mitral position under the pulsatile flow condition. The test program included measurements of velocity and turbulent stresses at 5 downstream locations. The study was carried out using a sophisticated cardiac simulator in conjunction with a highly sensitive 2 component laser Doppler anemometer (LDA) system. The continuous monitoring of parametric time histories revealed useful details about the complex flow and helped to establish the locations and times of the peak parameter values. Based upon the nondimensional presentation of data, the following general conclusions can be made. First, all the 5 valve designs created elevated turbulent stresses during the accelerating and peak flow phases, presenting the possibility of thromboembolism and perhaps hemolysis. Second, the difference in valve configuration seemed to affect the flow characteristics; third, the bileaflet design of the St. Jude valve appeared to create a lower turbulence stress level.

  15. The Letter of Jude and Graeco-Roman Invective

    Directory of Open Access Journals (Sweden)

    Alicia J. Batten

    2014-02-01

    Full Text Available Many have attempted to identify the opponents in Jude and have addressed the manner in which the author characterises this group. Moreover, scholars have expended considerable energy on the analysis and explication of Jude’s rhetorical structure and style, and there is wide consensus that as a text, Jude is a sophisticated letter. However, less work has attended to the evaluation of Jude within the tradition of Graeco-Roman invective. In comparing verses from Jude to some examples from such literature, we find similar themes. In particular, the letter of Jude and some Graeco-Roman moralists engage in a particular tactic to undermine, even destroy, the character of their opponents. They both present them as effeminates, which, although a stereotype, is one of the worst insults a writer or orator could wage against an adversary. This article argues that Jude engages in such character assassination, invoking effeminacy in the manner that he describes his opponents’ behaviour, and placing them in a long line of debauched and condemned figures from ages past.

  16. Amplatzer Amulet left atrial appendage occluder entrapment through mitral valve.

    Science.gov (United States)

    González-Santos, Jose María; Arnáiz-García, María Elena; Arribas-Jiménez, Antonio; López-Rodríguez, Javier; Rodríguez-Collado, Javier; Vargas-Fajardo, María del Carmen; Dalmau-Sorlí, María José; Bueno-Codoñer, María Encarnación; Arévalo-Abascal, R Adolfo

    2013-11-01

    We report on a 77-year-old woman in whom percutaneous left atrial appendage (LAA) closure was performed. The patient had a left atrial myxoma resection 3 years previously, and 2 years later, she suffered a transient ischemic attack. Atrial fibrillation was detected and anticoagulation therapy was established. An episode of intracranial bleeding forced interruption of anticoagulation. Thus, percutaneous LAA closure with an Amplatzer Amulet LAA Occluder (St Jude Medical) was proposed. During the procedure, the LAA occluder migrated and became trapped in the mitral valve. Secondary massive mitral regurgitation and hemodynamic instability forced emergent cardiac surgery. Successful removal of the Amplatzer Amulet LAA Occluder was achieved. Copyright © 2013 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

  17. Fatalism in Thomas Hardy’s Jude the Obscure

    Institute of Scientific and Technical Information of China (English)

    Sun; Gengmei; Zhou; Juntao

    2014-01-01

    Hardy is distinguished for his deep understanding of human nature and his insight of human life and experience.This paper will make an exploration about the theme of Jude the Obscure,which conveys the strong sense of fatalism,to show Hardy’s life outlook and reveal his pessimistic views towards society and human nature.

  18. Fatalism in Thomas Hardy’s Jude the Obscure

    Institute of Scientific and Technical Information of China (English)

    Sun Gengmei; Zhou Juntao

    2014-01-01

    Hardy is distinguished for his deep understanding of human nature and his insight of human life and experience. This paper will make an exploration about the theme of Jude the Obscure, which conveys the strong sense of fatalism, to show Hardy’s life outlook and reveal his pessimistic views towards society and human nature.

  19. Platelet activation through a Bi-leaflet mechanical heart valve

    Science.gov (United States)

    Hedayat, Mohammadali; Borazjani, Iman

    2016-11-01

    Platelet activation is one of the major drawbacks of the Mechanical Heart Valves (MHVs) which can increase the risk of thrombus formation in patients. The platelet activation in MHVs can be due to the abnormal shear stress during the systole, the backward leakage flow during the diastole, and the flow through the hinge region. We investigate the contribution of each of the above mechanism to the activation of platelets in MHVs by performing simulations of the flow through the MHV and in the hinge region. The large scale heart valve simulations are performed in a straight aorta using a sharp interface curvilinear immersed boundary method along with a strong-coupling algorithm under physiological flow conditions. In addition, in order to perform the simulation of hinge region the flow field boundary conditions are obtained from the largescale simulations during a whole cardiac cycle. In order to investigate the role of hinge flow on platelet activation in MHVs, a 23mm St. Jude Medical Regent valve hinge with three different gap sizes is tested along with different platelet activation models to ensure the consistency of our results with different activation models. We compare the platelet activation of the hinge region against the bulk of the flow during one cardiac cycle. This work is supported by the American Heart Association Grant 13SDG17220022, and the computational resources were partly provided by Center for Computational Research (CCR) at University at Buffalo.

  20. Role of vortices in cavitation formation in the flow at the closure of a bileaflet mitral mechanical heart valve.

    Science.gov (United States)

    Li, Chi-Pei; Chen, Sheng-Fu; Lo, Chi-Wen; Lu, Po-Chien

    2012-03-01

    Bubble cavitation occurs in the flow field when local pressure drops below vapor pressure. One hypothesis states that low-pressure regions in vortices created by instantaneous valve closure and occluder rebound promote bubble formation. To quantitatively analyze the role of vortices in cavitation, we applied particle image velocimetry (PIV) to reduce the instantaneous fields into plane flow that contains information about vortex core radius, maximum tangential velocity, circulation strength, and pressure drop. Assuming symmetrical flow along the center of the St. Jude Medical 25-mm valve, flow fields downstream of the closing valve were measured using PIV in the mitral position of a circulatory mock loop. Flow measurements were made during successive time phases immediately following the impact of the occluder with the housing (O/H impact) at valve closing. The velocity profile near the vortex core clearly shows a typical Rankine vortex. The vortex strength reaches maximum immediately after closure and rapidly decreases at about 10 ms, indicating viscous dissipation; vortex strength also intensifies with rising pulse rate. The maximum pressure drop at the vortex center is approximately 20 mmHg, an insignificant drop relative to atmospheric vapor pressures, which implies vortices play a minor role in cavitation formation.

  1. Training medical students in bag-valve-mask technique as an alternative to mechanical ventilation in a disaster surge setting.

    Science.gov (United States)

    Lin, Janet Y; Bhalla, Naina; King, Reneé A

    2009-01-01

    The objective of this study was to evaluate the rapid training of medical students and their ability to provide effective manual ventilation using the bag-valve-mask technique. A rapid training session highlighting essential aspects of the correct bag-valve-mask technique was given to 31 medical students. This was followed by a simulated experience with a certified respiratory therapist, monitored according to a checklist of essential bag-valve-mask (BVM) competency requirements. Pre-test and post-test surveys assessed the medical students' knowledge and ability to provide adequate BVM technique. Thirty-one students participated. Pre-survey results demonstrated a clear identification of the potential risk for a disaster (pandemic, natural, bioterrorist) with 55% of students responding that a definite risk did exist. Their usefulness in such an event also was ascertained with 55% of students replying they would assist with basic medical tasks, assist doctors, or assist with cardiopulmonary resuscitation. Post-survey results administered after a 30-minute didactic session on the basic features of resuscitation equipment and the essential components of BVM technique demonstrated that a majority of students knew the proper head positioning maneuvers in cases not involving trauma (93%) and in cases involving trauma (72%). All students completed and passed the competency checklist. Medical students can be rapidly trained and be utilized as a potential resource to carry out the potentially lifesaving task of manual ventilation using the BVM technique in a disaster situation in which the availability of mechanical ventilators and respiratory therapists may be limited.

  2. Medical expertise of young people of military age with mitral valve prolapse

    Directory of Open Access Journals (Sweden)

    Kuznetsova M.A.

    2013-03-01

    Full Text Available The last decade is characterized by a sharp decrease in psychosomatic health of young people of military age and growth of level of cardiovascular pathology. It is promoted by social and economic transfor¬mations in the country, growth of a psychoemotional pressure, decrease in level of the material income of the population, food of non-full value, alcoholism and drug addiction, health system destruction. The special place in the structure of cardiovascular pathology of young men of military age is occupied by the prolapse of the mitral valve (PMV. In health system PMV is considered as pathology of young able-bodied age and most often is not treated as pathology in general, until cardiac violations (violations of heart rhythm and conductivity, clinically significant mitral regurgitation, etc. develop. This position is unacceptable relative to recruits, whose daily activity is entailed with influence of a complex of extreme factors of the military and professional environment. In specific conditions of military service (a strict regulation of mode of work and rest, high degree of a physical and psychoemotional pressure, elements of hypovitaminosis, etc., possibilities of adaptation of the young man with PMV are significantly complicated. Any minor changes of the environment can gain critical importance, lead to exhaustion of reserve potential of an organism, decompensation of bodies and systems responsible for adaptation. In the absence of a significant arrhythmic syndrome and/or signs of cardiac insufficiency, recruits with pathology of cardiovascular system (CCC, as a rule, are admitted fit for military service. However level of functional condition of an organism of this category of persons does not allow them to fulfill official duties in full measure. They lag behind in the program of educational battle training, differ in lowered ability to work, absence of motivation in performance of the official duties, constant complaints on a health

  3. Valve Disease

    Science.gov (United States)

    ... heart valves, valve insufficiency, valve regurgitation, valve stenosis, valvular heart disease Every time your heart beats, blood flows into, ... removed from the market after being linked to heart valve disease. An infection in the lining of the heart's ...

  4. Early investigation of silver-coated Silzone heart valves prosthesis in 126 patients.

    Science.gov (United States)

    Auer, J; Berent, R; Ng, C K; Punzengruber, C; Mayr, H; Lassnig, E; Schwarz, C; Puschmann, R; Hartl, P; Eber, B

    2001-11-01

    Permanent silver (Silzone) coating of the sewing cuff of St. Jude Medical prosthetic heart valves may reduce the rate of prosthetic valve endocarditis (PVE). However, the incidence of paravalvular leaks and stroke in patients after implantation of Silzone-coated heart valve prostheses is largely unknown. Complications were analyzed among 126 consecutive patients (78 males, 48 females; mean age 64.7 years; range: 40-80 years) who received Silzone-coated prostheses at our institution between February 1998 and December 1999. Among patients, 94 had aortic valve replacement, 29 mitral valve replacement, and three had aortic and mitral valve replacement. Concomitant cardiac procedures (mainly coronary bypass) were performed in 47 patients (37.3%). Hospital mortality was 1.6% (2/126) and freedom from valve-related mortality 99.2+/-0.9%. Total follow up was 137.4 patient-years, and 98.4% complete. Strokes or transitory ischemic attacks (TIAs) occurred in four cases (two strokes, two TIAs; stroke rate 1.5%/year; 95% CI 0.4-2.6%/year; stroke+TIA rate 3%/year; 95% CI 0.4-5.25%/year). There was no case of prosthetic valve dysfunction or PVE. Freedom from reoperation due to procedure-associated complications was 97.6% (one aortic dissection, two major bleeds). Paravalvular leak was detected in 19 cases, and graded trivial or mild in 17 cases (11 grade 0-I, six grade I), and moderate in two cases (grade I-II in one, grade II in one). No patient needed reoperation due to paravalvular leak. Left ventricular (LV) function was normal in 80 cases, but was impaired mildly in 20 cases, moderately in 16, and severely in eight. Bicycle exercise testing in 92 patients (73%) showed median exercise performance (81.4+/-23.9% of normal) after correction for age and weight. Cerebral magnetic resonance imaging was performed in 64 patients (50.8%); median MRI score was 2.0+/-1.8 according to a 12-scaled score system. The overall incidence of echocardiographic paravalvular leak graded more than

  5. Valve-in-Valve Replacement Using a Sutureless Aortic Valve

    Science.gov (United States)

    Dohmen, Pascal M.; Lehmkuhl, Lukas; Borger, Michael A.; Misfeld, Martin; Mohr, Friedrich W.

    2016-01-01

    Patient: Female, 61 Final Diagnosis: Tissue degeneration Symptoms: Dyspnea Medication: — Clinical Procedure: Redo valve replacement Specialty: Surgery Objective: Rare disease Background: We present a unique case of a 61-year-old female patient with homograft deterioration after redo surgery for prosthetic valve endocarditis with root abscess. Case Report: The first operation was performed for type A dissection with root, arch, and elephant trunk replacement of the thoracic aorta. The present re-redo surgery was performed as valve-in-valve with a sutureless aortic biopros-thesis. The postoperative course was uneventful and the patient was discharged on day 6. Conclusions: The current case report demonstrates that sutureless bioprostheses are an attractive option for surgical valve-in-valve procedures, which can reduce morbidity and mortality. PMID:27694795

  6. Blood damage through a bileaflet mechanical heart valve: a quantitative computational study using a multiscale suspension flow solver.

    Science.gov (United States)

    Min Yun, B; Aidun, Cyrus K; Yoganathan, Ajit P

    2014-10-01

    Bileaflet mechanical heart valves (BMHVs) are among the most popular prostheses to replace defective native valves. However, complex flow phenomena caused by the prosthesis are thought to induce serious thromboembolic complications. This study aims at employing a novel multiscale numerical method that models realistic sized suspended platelets for assessing blood damage potential in flow through BMHVs. A previously validated lattice-Boltzmann method (LBM) is used to simulate pulsatile flow through a 23 mm St. Jude Medical (SJM) Regent™ valve in the aortic position at very high spatiotemporal resolution with the presence of thousands of suspended platelets. Platelet damage is modeled for both the systolic and diastolic phases of the cardiac cycle. No platelets exceed activation thresholds for any of the simulations. Platelet damage is determined to be particularly high for suspended elements trapped in recirculation zones, which suggests a shift of focus in blood damage studies away from instantaneous flow fields and toward high flow mixing regions. In the diastolic phase, leakage flow through the b-datum gap is shown to cause highest damage to platelets. This multiscale numerical method may be used as a generic solver for evaluating blood damage in other cardiovascular flows and devices.

  7. Estimation of viscous dissipative stresses induced by a mechanical heart valve using PIV data.

    Science.gov (United States)

    Li, Chi-Pei; Lo, Chi-Wen; Lu, Po-Chien

    2010-03-01

    Among the clinical complications of mechanical heart valves (MHVs), hemolysis was previously thought to result from Reynolds stresses in turbulent flows. A more recent hypothesis suggests viscous dissipative stresses at spatial scales similar in size to red blood cells may be related to hemolysis in MHVs, but the resolution of current instrumentation is insufficient to measure the smallest eddy sizes. We studied the St. Jude Medical (SJM) 27 mm valve in the aortic position of a pulsatile circulatory mock loop under physiologic conditions with particle image velocimetry (PIV). Assuming a dynamic equilibrium assumption between the resolved and sub-grid-scale (SGS) energy flux, the SGS energy flux was calculated from the strain rate tensor computed from the resolved velocity fields and the SGS stress was determined by the Smagorinsky model, from which the turbulence dissipation rate and then the viscous dissipative stresses were estimated. Our results showed Reynolds stresses up to 80 N/m2 throughout the cardiac cycle, and viscous dissipative stresses below 12 N/m2. The viscous dissipative stresses remain far below the threshold of red blood cell hemolysis, but could potentially damage platelets, implying the need for further study in the phenomenon of MHV hemolytic complications.

  8. [Long-term results of conventional aortic valve replacement for small aortic annulus].

    Science.gov (United States)

    Miura, Y; Miyairi, T; Kitamura, T; Kigawa, I; Fukuda, S

    2006-04-01

    We studied cardiac function, clinical outcome and quality of life (QOL) long after aortic valve replacement for pure aortic stenosis. Forty-four patients in small group [St. Jude Medical (SJM) 17 HP, 19 A], and 69 patients in non-small group (19 HP, 21 A, 23 A) operated on from 1984 to 2004 were enrolled in this study. We assessed the clinical data, aortic pressure gradient, left ventricular mass index (LVMI), and ejection fraction (EF) by preoperative and postoperative echocardiography. Moreover to evaluate QOL after the operation, we performed SF-36 used for the evaluation of health and QOL worldwide. Mean follow-up is 7.1 +/- 4.8 years in small group, and 6.8 +/- 4.6 years in non-small group. There were 2 hospital deaths in small group, and 1 in non-small group. The actual survival rate at 10-year were 89.2% in small group, and 85.6% in non-small group. There was no significant difference in hospital mortality, LVMI, long-term survival rate, and the scores of SF-36 between the 2 groups. The use of small sized prosthetic valves in patients with small aortic annulus might be justified when there is no patient-prosthesis mismatch.

  9. Hemodynamic function of the standard St. Jude bileaflet disc valve has no clinical impact 10 years after aortic valve replacement

    DEFF Research Database (Denmark)

    Lund, Ole; Dorup, Inge; Emmertsen, Kristian

    2005-01-01

    .05), lower LVEF, and higher LVEDD and LVMi than 26 without. Peak gradient was greater than 35 mmHg in five hypertensive patients with normal LVEF but lesser than 30 mmHg in six with impaired LVEF. Supranormal LVEF and severe size mismatch identified the remaining patients (N=3) with peak gradient above 35 mm...

  10. Cinematics and sticking of heart valves in pulsatile flow test.

    Science.gov (United States)

    Köhler, J; Wirtz, R

    1991-05-01

    The aim of the project was to develop laboratory test devices for studies of the cinematics and sticking behaviour of technical valve protheses. The second step includes testing technical valves of different types and sizes under static and dynamic conditions. A force-deflection balance was developed in order to load valve rims by static radial forces until sticking or loss of a disc (sticking- and clamping-mould point) with computer-controlled force deflection curves. A second deflection device was developed and used for prosthetic valves in the aortic position of a pulsatile mock circulation loop with simultaneous video-cinematography. The stiffness of technical valve rims varied between 0.20 (St. Jude) and about 1.0 N/micron (metal rim valves). The stiffness decreased significantly with increasing valve size. Sticking under pulsatile flow conditions was in good agreement with the static deflection measurements. Hence, valve sticking with increasing danger of thrombus formation is more likely with a less stiff valve rim. In the case of forces acting perpendicularly to the pendulum axis, the clamping mould-point of the valve can be reached, followed by disc dislodgement.

  11. Two-layer Lab-on-a-chip (LOC) with passive capillary valves for mHealth medical diagnostics.

    Science.gov (United States)

    Balsam, Joshua; Bruck, Hugh Alan; Rasooly, Avraham

    2015-01-01

    There is a new potential to address needs for medical diagnostics in Point-of-Care (PoC) applications using mHealth (Mobile computing, medical sensors, and communications technologies for health care), a mHealth based lab test will require a LOC to perform clinical analysis. In this work, we describe the design of a simple Lab-on-a-chip (LOC) platform for mHealth medical diagnostics. The LOC utilizes a passive capillary valve with no moving parts for fluid control using channels with very low aspect ratios cross sections (i.e., channel width ≫ height) achieved through transitions in the channel geometry via that arrest capillary flow. Using a CO2 laser in raster engraving mode, we have designed and fabricated an eight-channel LOC for fluorescence signal detection fabricated by engraving and combining just two polymer layers. Each of the LOC channels is capable of mixing two reagents (e.g., enzyme and substrate) for various assays. For mHealth detection, we used a mobile CCD detector equipped with LED multispectral illumination in the red, green, blue, and white range. This technology enables the development of low-cost LOC platforms for mHealth whose fabrication is compatible with standard industrial plastic fabrication processes to enable mass production of mHealth diagnostic devices, which may broaden the use of LOCs in PoC applications, especially in global health settings.

  12. Application of Regent mechanical valve in patients with small aortic annulus: 3-year follow-up

    Directory of Open Access Journals (Sweden)

    Zhao Dong

    2012-09-01

    Full Text Available Abstract Background Aortic valve replacement (AVR with a small aortic annulus is always challenging for the cardiac surgeon. In this study, we sought to evaluate the midterm performance of implantation with a 17-mm or 19-mm St. Jude Medical Regent (SJM Regent mechanical valve in retrospective consecutive cohort of patients with small aortic annulus (diameter ≤ 19 mm. Methods From January 2008 to April 2011, 40 patients (31 female, mean age = 47.2 ± 5.8 years with small aortic annulus (≤19 mm in diameter underwent aortic valve replacement with a 17-mm or 19-mm St. Jude Medical Regent (SJM Regent mechanical valve. Preoperative mean body surface area, New York Heart Association class, and mean aortic annulus were 1.61 ± 0.26 m2, 3.2 ± 0.4, and 18 ± 1.4 mm respectively. Patients were divided into two groups, according to the implantation of 17 mm SJM Regent mechanical valve (group 1, n = 18 or 19 mm SJM Regent valve (group 2, n = 22. All patients underwent echocardiography examination preoperatively and at one year post-operation. Results There were no early deaths in either group. Follow-up time averaged 36 ± 17.6 months. The mean postoperative New York Heart Association class was 1.3 ± 0.6 (p 2/m2 to 69.8 ± 9.3%, 41.4 ± 8.3%, and 0.92 ± 0.10 cm2/m2 respectively (P 2, 46.1 ± 8.5 mmHg to 86.7 ± 18.2 g/m2 , 13.7 ± 5.2 mmHg respectively. In group 2, the LVEF, LVFS and EOAI increased from 45.9% ± 9.7%, 30.7% ± 8.0%, and 0.81 ± 0.09 cm2/m2 to 77.4% ± 9.7%, 44.5% ± 9.6%, and 1.27 ± 0.11 cm2/m2 respectively, while the LVMI, and the aortic transvalvular pressure gradient decreased from 118.3 ± 27.6 g/m2, 44.0 ± 6.7 mmHg to 80.1 ± 19.7 g/m2, 10.8 ± 4.1 mmHg as well. The prevalence of PPM was documented in 2 patients in Group 1. Conclusions Patients with small aortic annulus and body surface

  13. The Ideological Questions of Marriage in Thomas Hardy’s Jude the Obscure

    Directory of Open Access Journals (Sweden)

    Saleh N.S.

    2015-12-01

    Full Text Available As one of the prominent ideologies of the nineteenth-century— in a complex interrelation with other contemporary ideological discourses particularly femininity and marriage—religion adopts a critical stance in Hardy’s presentation of characters. Breaching the religio-conventional image of femininity as “Angel in the House” and “Cow Woman,” Hardy’s Jude the Obscure (1895 is indeed deemed to be his milestone in presenting his anti-Christian attitudes towards the contemporary religion. This study aims to present Hardy’s outright hostility towards the nineteenth-century Christianity through his creation of non-conformist characters, necessitating a parallel study with other contemporary discourses regarding marriage and femininity, and conflict with the religion of the time. Hardy’s magnum opus, the work on which he was to stake his final reputation as a novelist, was clearly Jude the Obscure which as a noticeable socio-religious experimentation of the late nineteenth-century, reveals Hardy’s perception of new ideas about femininity and marriage by presenting the hot contemporary issues of “New Woman” and “Free Union” through the development and presentation of Sue Bridehead and her free union with Jude, respectively. Hardy’s presentation of Sue Bridehead as a “New Woman,” and employing the “Free Union” in marked contrast with the nineteenth-century convention of marriage as a “Bonded Pair” is Hardy’s closing upshot of his final novelistic attempt. The non-conformist Jude and Sue are presented as figures touching the Victorian Christian standards of morality, while, the final tragic destiny of Jude and Sue’s helplessness attest to the writer’s substantial contribution as a Victorian male novelist to the ideologies circulating at the time.

  14. The Ideological Questions of Marriage in Thomas Hardy’s Jude the Obscure

    Directory of Open Access Journals (Sweden)

    Salman Saleh, N.

    2015-01-01

    Full Text Available As one of the prominent ideologies of the nineteenth-century— in a complex interrelation with other contemporary ideological discourses particularly femininity and marriage—religion adopts a critical stance in Hardy’s presentation of characters. Breaching the religio-conventional image of femininity as “Angel in the House” and “Cow Woman,” Hardy’s Jude the Obscure (1895 is indeed deemed to be his milestone in presenting his anti-Christian attitudes towards the contemporary religion. This study aims to present Hardy’s outright hostility towards the nineteenth-century Christianity through his creation of non-conformist characters, necessitating a parallel study with other contemporary discourses regarding marriage and femininity, and conflict with the religion of the time. Hardy’s magnum opus, the work on which he was to stake his final reputation as a novelist, was clearly Jude the Obscure which as a noticeable socio-religious experimentation of the late nineteenth-century, reveals Hardy’s perception of new ideas about femininity and marriage by presenting the hot contemporary issues of “New Woman” and “Free Union” through the development and presentation of Sue Bridehead and her free union with Jude, respectively. Hardy’s presentation of Sue Bridehead as a “New Woman,” and employing the “Free Union” in marked contrast with the nineteenth-century convention of marriage as a “Bonded Pair” is Hardy’s closing upshot of his final novelistic attempt. The non-conformist Jude and Sue are presented as figures touching the Victorian Christian standards of morality, while, the final tragic destiny of Jude and Sue’s helplessness attest to the writer’s substantial contribution as a Victorian male novelist to the ideologies circulating at the time.

  15. Prosthetic Valve Thrombosis: Diagnosis and Management.

    Science.gov (United States)

    Garg, Jalaj; Palaniswamy, Chandrasekar; Pinnamaneni, Sowmya; Sarungbam, Judy; Jain, Diwakar

    2016-01-01

    St. Jude mechanical prosthesis is the most commonly used prosthetic device with least valvular complications with excellent hemodynamics. However, prosthetic valve thrombosis is one of the serious complications, with rates between 0.03% and 0.13% per patient-year depending on the type of anticoagulation used and compliance to the therapy. Transthoracic echocardiography (TTE) is the initial screening tool (class I) that would provide clues for the assessment of valvular hemodynamics. Fluoroscopy is an alternate imaging modality for the assessment of mechanical leaflet motion, especially in patients when prosthetic valves are difficult to image on TTE or transesophageal echocardiography. A complete fluoroscopic evaluation of a prosthetic valve includes assessment of valvular motion and structural integrity. Opening and closing angles can be measured fluoroscopically to determine whether a specific valve is functioning properly. We discuss a case of a 91-year-old man with thrombosis of bileaflet mechanical mitral prosthesis that was demonstrated on real-time fluoroscopy (not evident on TTE). An algorithmic approach to diagnosis and management of prosthetic heart valve thrombosis is outlined.

  16. Valve selection in aortic valve endocarditis

    Science.gov (United States)

    Zubrytska, Yana

    2016-01-01

    Aortic prosthetic valve endocarditis (PVE) is a potentially life-threatening disease. Mortality and incidence of infective endocarditis have been reduced in the past 30 years. Medical treatment of aortic PVE may be successful in patients who have a prompt response after antibiotic treatment and who do not have prosthetic dysfunction. In advanced stages, antibiotic therapy alone is insufficient to control the disease, and surgical intervention is necessary. Surgical treatment may be lifesaving, but it is still associated with considerable morbidity and mortality. The aim of surgery is to perform a radical excision of all infected and necrotic tissue, reconstruction of the left ventricle outflow tract, and replacement of the aortic valve. There is no unanimous consensus on which is the optimal prosthesis to implant in this context, and several surgical techniques have been suggested. We aim to analyze the efficacy of the surgical treatment and discuss the issue of valve selection in patients with aortic valve endocarditis.

  17. Development of a PVA Hydrogel for Bioprosthetic Heart Valve Stent and Other Medical Applications

    Institute of Scientific and Technical Information of China (English)

    Z.F.Zhang; A.J.Hui; D.R.Boughner; G.Campbell; W.K.Wan

    2000-01-01

    Polyvinyl alcohol (PVA) hydrogel (15%w/w) was processed by freezing and thawing from one through six thermal cycles to obtain wide range of mechanical properties. The materials were tested under uniaxial tension and results show that matching mechanical properties to that of porcine aortic root can be achieved. A fatigue machine for elastomer materials and tissues was built and fatigue test on PVA sample was carried out. The test results show that the PVA has good fatigue property. The stent prototype was designed and successfully made by mold casting method. Some potential medical applications are discussed.

  18. Anticoagulation for Prosthetic Valves

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Kaneko

    2013-01-01

    Full Text Available Implantation of prosthetic valve requires consideration for anticoagulation. The current guideline recommends warfarin on all mechanical valves. Dabigatran is the new generation anticoagulation medication which is taken orally and does not require frequent monitoring. This drug is approved for treatment for atrial fibrillation and venous thromboembolism, but the latest large trial showed that this drug increases adverse events when used for mechanical valve anticoagulation. On-X valve is the new generation mechanical valve which is considered to require less anticoagulation due to its flow dynamics. The latest study showed that lower anticoagulation level lowers the incidence of bleeding, while the risk of thromboembolism and thrombosis remained the same. Anticoagulation poses dilemma in cases such as pregnancy and major bleeding event. During pregnancy, warfarin can be continued throughout pregnancy and switched to heparin derivative during 6–12 weeks and >36 weeks of gestation. Warfarin can be safely started after 1-2 weeks of discontinuation following major bleeding episode.

  19. Double Valve Replacement (Mitral and Aortic for Rheumatic Heart Disease: A 20-year experience with 300 patients.

    Directory of Open Access Journals (Sweden)

    Prashant Mishra

    2016-09-01

    Full Text Available Introduction: Rheumatic heart disease still remains one of the leading causes of congestive heart failure and death owing to valvular pathologies, in developing countries. Valve replacement still remains the treatment of choice in such patients.The aim of this study wasto analyze the postoperative outcome of  double valve replacement (Mitral and Aortic in patients of rheumatic heart disease. Materials and Methods: Between 1988 and 2008, 300 patients of rheumatic heart disease underwent double (Mitral and Aortic valve replacement with Starr Edwards valve or St Jude mechanical valve prosthesis were implanted. These patients were studied retrospectively for preoperative data and postoperative outcome including causes of early and late deaths and the data was analyzed statistically. Results: The 30-day hospital death rate was 11.3% andlate death occurred in 11.6%. Anticoagulant regimen was followed to maintain the target pro-thrombin time at 1.5 times the control value. The actuarial survival (exclusive of hospital mortality was 92.4%, 84.6%, and 84.4%, per year at 5, 10, and 20 years, respectively Conclusions: In view of the acknowledged advantageof superior durability, increased thromboresistance in our patient population, and its cost effectiveness the Starr-Edwards ball valve or St. Jude valve is the mechanical prosthesis of choice for advanced combined valvular disease. The low-intensity anticoagulant regimen has offered suffcient protection against thromboembolism as well as hemorrhage.

  20. Fatores de risco hospitalar para implante de bioprótese valvar de pericárdio bovino Hospital risk factors for bovine pericardial bioprosthesis valve implantation

    Directory of Open Access Journals (Sweden)

    Mateus W. De Bacco

    2007-08-01

    Full Text Available FUNDAMENTO: Identificação de fatores de risco pré-operatórios na cirurgia cardíaca valvar visa melhor resultado cirúrgico pela possível neutralização de condições relacionadas com morbi-mortalidade aumentada. OBJETIVO: Este estudo objetiva identificar fatores de risco hospitalar em pacientes submetidos a implante de bioprótese de pericárdio bovino. MÉTODOS: Estudo retrospectivo incluindo 703 pacientes consecutivos submetidos a implante de pelo menos uma bioprótese de pericárdio bovino St. Jude Medical-Biocor® de setembro de 1991 a dezembro de 2005 no Instituto de Cardiologia do RS, sendo 392 aórticos, 250 mitrais e 61 mitro-aórticos. Analisadas as características sexo, idade, índice de massa corporal, classe funcional (New York Heart Association - NYHA, fração de ejeção, lesão valvar, hipertensão arterial sistêmica, diabete melito, função renal, arritmias cardíacas, cirurgia cardíaca prévia, revascularização miocárdica, plastia tricúspide e caráter eletivo, de urgência ou de emergência da cirurgia. Desfecho primordial foi mortalidade hospitalar. Utilizou-se regressão logística para examinar relação entre fatores de risco e mortalidade hospitalar. RESULTADOS: Ocorreram 101 (14,3% óbitos hospitalares. Características significativamente relacionadas à mortalidade aumentada foram sexo feminino (p 2,4mg/dl (p=0,004, classe funcional IV (pBACKGROUND: Identification of preoperative heart valve surgery risk factors aim to improve surgical outcomes with the possibility to offset conditions related to increased morbidity and mortality. OBJECTIVE: Intent of this study is to identify hospital risk factors in patients undergoing bovine pericardial bioprosthesis implantation. METHODS: Retrospective study including 703 consecutive patients who underwent implantation of at least one St. Jude Medical-Biocor™ bovine pericardial bioprosthesis between September 1991 and December 2005 at the Rio Grande do Sul

  1. When the dead are alive! The influence of the living dead in the letter of Jude

    Directory of Open Access Journals (Sweden)

    Stephan J. Joubert

    2002-11-01

    Full Text Available This essay investigates the impact of the deceased on  the audience to which the letter of Jude was originally addressed. A construct of the influence of the “living dead” in ancient Babylon, Israel, the Graeco-Roman world and in African tradition serves as a basic cognitive map to come to terms with Jude’s views on the dead. It is argued that, since the wicked dead, who are being physically punished in  the underworld,  are kept alive  in the collective memory of Jude’s community and since their deeds are re-enacted in the sinful behavior  of intruders in their midst, their lives are influenced by  the “presence” of these living dead. On the other hand and, although Jude does not deal with the physical whereabouts of the righteous death, he and his readers know that their postmortem honour is still intact. The righteous in this community is assured that God protects the integrity of the faithful dead.

  2. Subchronic use of the St. Jude centrifugal pump as a mechanical assist device in calves.

    Science.gov (United States)

    Curtis, J; Wagner-Mann, C; Mann, F; Demmy, T; Walls, J; Turk, J

    1996-06-01

    The purpose of this experiment was to study the effects of the St. Jude Lifestream centrifugal pump on hemodynamic and hematologic parameters and the incidence of postmortem findings in a subchronic ex vivo left ventricular assist animal model. Five calves were implanted with the pump as a left ventricular assist device (left atrial to thoracic aorta bypass) and studied for 96 h of continuous pumping under identical conditions. Heparin (100 IU/kg) was administered only in the initial saline pump prime. Throughout the protocol, mean arterial and central venous pressures averaged 102.1 +/- 4.6 and 3.4 +/- 2.2 mm Hg, respectively. Pump flow was 47.8 +/- 8.4 ml/kg/min at a mean pump speed of 1,676.3 +/- 106.1 rpm. No clinical abnormalities or mechanical malfunctions attributable to the pump were detected during the 96 h of continuous pumping for each calf. Mean plasma-free hemoglobin after 96 h was 3.9 +/- 3.7 mumol/L (p = 0.337 compared to baseline). At post mortem, renal infarctions were detected in 1 calf. No other pump-associated lesions were detected in any of the other calves. We have concluded that the St. Jude Lifestream centrifugal pump functions reliably during 96 h of continuous left heart bypass in a calf model.

  3. Lifestyle and metabolic syndrome in adult survivors of childhood cancer: a report from the St. Jude Lifetime Cohort Study.

    Science.gov (United States)

    Smith, Webb A; Li, Chenghong; Nottage, Kerri A; Mulrooney, Daniel A; Armstrong, Gregory T; Lanctot, Jennifer Q; Chemaitilly, Wassim; Laver, Joseph H; Srivastava, Deo Kumar; Robison, Leslie L; Hudson, Melissa M; Ness, Kirsten K

    2014-09-01

    Childhood cancer survivors (CCS) are at an increased risk of developing metabolic syndrome (MetSyn), which may be reduced with lifestyle modifications. The purpose of this investigation was to characterize lifestyle habits and associations with MetSyn among CCS. CCS who were ≥ 10 years from diagnosis, aged > 18 years, and participating in the St. Jude Lifetime Cohort Study completed medical and laboratory tests and a food frequency questionnaire. The Third Report of the National Cholesterol Education Program Adult Treatment Panel criteria were used to classify participants with MetSyn. Anthropometric, food frequency questionnaire, and self-reported physical activity data were used to characterize lifestyle habits according to World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) recommendations. Those who met ≥ 4 of 7 recommendations were classified as having followed guidelines. Sex-stratified log-binomial regression models were used to evaluate associations between dietary/lifestyle habits and MetSyn, adjusted for age, age at cancer diagnosis, receipt of cranial radiotherapy, education, and household income. Among 1598 CCS (49.2% of whom were male, with a median age of 32.7 years [range, 18.9 years-60.0 years]), 31.8% met criteria for MetSyn and 27.0% followed WCRF/AICR guidelines. Females who did not follow WCRF/AICR guidelines were 2.4 times (95% confidence interval, 1.7-3.3) and males were 2.2 times (95% confidence interval, 1.6-3.0) more likely to have MetSyn than those who followed WCRF/AICR guidelines. Adherence to a heart-healthy lifestyle is associated with a lower risk of MetSyn among CCS. There is a need to determine whether lifestyle interventions prevent or remediate MetSyn in CCS. © 2014 American Cancer Society.

  4. Neurocognitive Outcomes Decades After Treatment for Childhood Acute Lymphoblastic Leukemia: A Report From the St Jude Lifetime Cohort Study

    Science.gov (United States)

    Krull, Kevin R.; Brinkman, Tara M.; Li, Chenghong; Armstrong, Gregory T.; Ness, Kirsten K.; Srivastava, Deo Kumar; Gurney, James G.; Kimberg, Cara; Krasin, Matthew J.; Pui, Ching-Hon; Robison, Leslie L.; Hudson, Melissa M.

    2013-01-01

    Purpose To determine rates, patterns, and predictors of neurocognitive impairment in adults decades after treatment for childhood acute lymphoblastic leukemia (ALL). Patients and Methods Survivors of childhood ALL treated at St Jude Children's Research Hospital who were still alive at 10 or more years after diagnosis and were age ≥ 18 years were recruited for neurocognitive testing. In all, 1,014 survivors were eligible, 738 (72.8%) agreed to participate, and 567 (76.8%) of these were evaluated. Mean age was 33 years; mean time since diagnosis was 26 years. Medical record abstraction was performed for data on doses of cranial radiation therapy (CRT) and cumulative chemotherapy. Multivariable modeling was conducted and glmulti package was used to select the best model with minimum Akaike information criterion. Results Impairment rates across neurocognitive domains ranged from 28.6% to 58.9%, and those treated with chemotherapy only demonstrated increased impairment in all domains (all P values < .006). In survivors who received no CRT, dexamethasone was associated with impaired attention (relative risk [RR], 2.12; 95% CI, 1.11 to 4.03) and executive function (RR, 2.42; 95% CI, 1.20 to 4.91). The impact of CRT was dependent on young age at diagnosis for intelligence, academic, and memory functions. Risk for executive function problems increased with survival time in a CRT dose-dependent fashion. In all survivors, self-reported behavior problems increased by 5% (RR, 1.05; 95% CI, 1.01 to 1.09) with each year from diagnosis. Impairment was associated with reduced educational attainment and unemployment. Conclusion This study demonstrates persistent and significant neurocognitive impairment in adult survivors of childhood ALL and warrants ongoing monitoring of brain health to facilitate successful adult development and to detect early onset of decline as survivors mature. PMID:24190124

  5. Tricuspid Valve Replacement, Mechnical vs. Biological Valve, Which Is Better?

    Directory of Open Access Journals (Sweden)

    Haitham Akram Altaani

    2013-06-01

    Full Text Available Background: The initial trial in tricuspid surgery is repair; however, replacement is done whenever the valve is badly diseased. Tricuspid valve replacement comprises 1.7% of all tricuspid valve surgeries. Materials and Methods: The present retrospective study was performed using the medical records of 21 cases who underwent tricuspid valve replacement from January 2002 until the end of December 2010. The mean age of the participants was 52.3±8.8 years and 66.7% were females. In addition, tricuspid valve replacement was associated with mitral valve surgery, aortic valve surgery, and both in 14.3%, 4.8%, and 33.3% of the cases, respectively. Yet, isolated tricuspid valve replacement and redo surgery were performed in 10 cases (47.6% and 8 cases (38.1%, respectively. Besides, trial of repair was done in 14 cases (66.7%. Moreover, biological and mechanical valves were used in 76.2% and 23.8% of the patients, respectively. Results: According to the results, early mortality was 23.8% and one year survival was 66.7%. Moreover, early mortality was caused by right ventricular failure, multiorgan failure, medistinitis, and intracerbral bleeding in 42%, 28.6%, 14.3%, and 14.3% of the cases, respectively. In addition, 57.1% of the deaths had occurred in the cases where the biological valve was used, while 42.9% of the deaths had taken place where the mechanical one was utilized. Conclusions: The patients who require tricuspid valve replacement are usually high risk surgical candidates with early and long term mortality. The findings of the current study showed no significant hemodynamic difference between mechanical and biological valves.

  6. Sue Bridehead:The Girl of the Period in Thomas Hardy’s Jude the Obscure

    Institute of Scientific and Technical Information of China (English)

    徐苏

    2014-01-01

    Jude the Obscure was Thomas Hardy’s last novel creation, and he spent eight year from preparation to publication. Al-though this novel received a lot of criticisms instead of praises when it came out, it also can be considered as Thomas Hardy ’s classical works. The theme of this novel is so brave to explore the existing women ’s living circumstances in that time. With the industrial revolution in England, new thoughts and ideas sprang out. Women were no longer belonging to husband and family, and they began to be aware of their social roles and reconsider their identity in society and marriage. The aim of the paper is to analyze this novel from the feministic perspective and re-read the character of Sue Bridehead in the light of the theory“the girl of the period”.

  7. Pseudepigraphy and the Petrine school: Spirit and tradition in 1 and 2 Peter and Jude

    Directory of Open Access Journals (Sweden)

    Patrick Chatelion Counet

    2006-09-01

    Full Text Available This article identifies four “patterns of religion” (E P Sanders in the pseudepigraphic letters of Peter and Jude in order to support the hypothesis of a “Petrine school” (J H Elliott. The first pattern that connects the letters is a Geisttradition (K Aland, guaranteeing continuity of tradition. The second is the interrelationship between faith and ethics (fides quae and fides qua. The combination of sanctification and eschatology is a third pattern connecting the three documents. Finally, two florilegia can be identified (one from the Old Testament and apocrypha, and one from the chokmatic tradition, suggesting a fourth pattern: a warning against ungodliness and infidelity. The existence of a Petrine group could represent a preliminary stage of subsequent Early Catholicism.

  8. Transapical transcatheter valve-in-valve replacement for deteriorated mitral valve bioprosthesis without radio-opaque indicators: the "invisible" mitral valve bioprosthesis.

    Science.gov (United States)

    Rossi, Marco Luciano; Barbaro, Cristina; Pagnotta, Paolo; Cappai, Antioco; Ornaghi, Diego; Belli, Guido; Presbitero, Patrizia

    2015-02-01

    In view of the high number of bioprosthetic valves implanted during the past 30 years, an increasing number of patients are coming to medical attention because of degenerated bioprostheses. Transcatheter aortic valve-in-valve implantation has been described as a less invasive alternative to re-operation to treat severe structural valve deterioration. As far as degenerated mitral valve bioprostheses are concerned, transcatheter transapical mitral valve-in-valve replacement (TMVR) has been less commonly performed, but may also become a viable alternative to re-do replacement surgery. We describe treatment of a degenerated bioprosthetic mitral valve, characterised by complete absence of any radio-opaque landmarks making the TMVR procedure very challenging.

  9. Maximizing prosthetic valve size with the Top Hat supra-annular aortic valve

    DEFF Research Database (Denmark)

    Aagaard, Jan; Geha, Alexander S.

    2007-01-01

    BACKGROUND AND AIM OF THE STUDY: The CarboMedics Top Hat supra-annular aortic valve allows a one-size (and often two-size) increase over the standard intra-annular valve. This advantage should minimize the risk of patient-prosthesis mismatch, where the effective prosthetic valve orifice area...

  10. Valve replacement in pediatric patients:a single center experience

    Institute of Scientific and Technical Information of China (English)

    YU Jian-hua; GUO Hong-wei; ZHANG Gong; WU Shu-ming; SONG Guang-min; SUN Wen-yu

    2011-01-01

    Background Reconstructive surgery is the primary goal in pediatric patients with valve disease.However,in cases with irreparable valve lesions,valve replacement is the only option.This study aimed to retrospectively analyze the clinical experience of heart valve prosthesis replacement in children.Methods Between January 1990 and July 2009,35 pediatric patients (16 boys,19 girls) underwent mechanical valve replacement in Shandong University Qilu Hospital.The ages ranged from 2.5 to 14 years (mean,(8.8±3.8) years) and body weight varied from 11 to 37 kg (mean,(22.1±5.2) kg).Mechanical valve replacement was performed because of congenital heart disease in 23 patients,rheumatic disease in ten patients and infective endocarditis in two patients.St.Jude bileaflet mechanical valves were implanted in all the 35 patients including mitral valve replacement (MVR) in 18,aortic valve replacement (AVR) in 12,tricuspid valve replacement (TVR) in two,AVR and MVR in two and MVR and TVR in one.The size of the prostheses ranged between 19 and 27 mm.All patients received long-term anticoagulation treatment with sodium warfarin,aiming to maintain an international normalized ratio between 1.5 to 2.0.Follow-up was performed in all the patients with a total follow-up of 119.4 patient-years.Results The operative mortality was 8.57% (3/35).One patient,who underwent cardiac debridement and AVR,died 2 hours after being admitted to the intensive care unit because of severe low cardiac output syndrome and ventricular fibrillation.Two patients died of cardiogenic shock and renal failure during initial hospitalization after the operation.One patient who received replacement of a tricuspid valve developed complete heart block requiring temporary pacing and recovered sinus rhythm 4 days later.Thirty-two patients survived and their cardiac function was in New York Heart Association (NYHA) class Ⅰ to class Ⅱ when discharged.Late events included hemorrhage and endocarditis.Two patients required

  11. The measurement of opening angle and orifice area of a bileaflet mechanical valve using multidetector computed tomography.

    Science.gov (United States)

    Lee, Dong-Hyeon; Youn, Ho-Joong; Shim, Sung-Bo; Lee, Sun-Hee; Jung, Jung-Im; Jung, Seung-Eun; Choi, Yun-Seok; Park, Chul-Soo; Oh, Yong-Seog; Chung, Wook-Sung; Kim, Jae-Hyung

    2009-04-01

    The aim of this study was to assess mechanical valve function using 64-slice multidetector computed tomography (MDCT). In 20 patients (mean age, 50+/-12 years; male-to-female ratio, 10:10), 30 St. Jude bileaflet mechanical valves (15 aortic and 15 mitral valves) were evaluated using MDCT. We selected images vertical and parallel to the mechanical valve. The valve orifice area (OA) and valve length were determined by manual tracing and the opening and closing angles were measured using a protractor. The OA and length of the mechanical valves were compared with the manufacturer's values. The geometric orifice areas (GOAs) based on the manufacturer's values and the OAs determined by MDCT were 3.4+/-0.2 cm(2) and 3.4+/-0.3 cm(2) for the mitral valves and 2.1+/-0.3 cm(2) and 2.1+/-0.4 cm(2) for the aortic valves, respectively. The correlation coefficients between the OA measures were 0.433 for the mitral valves and 0.874 for the aortic valves (both pvalves and 21.5+/-2.1 mm and 20.7+/-2.3 mm for the aortic valves, respectively. The correlation coefficients between the measures were 0.651 for the mitral valve and 0.846 for the aortic valve (both pvalves and 11.1+/-0.9 degrees and 120.6+/-1.7 degrees for the aortic valves, respectively. MDCT is an accurate modality with which to assess the function and morphology of bileaflet mechanical valves.

  12. Valve's Way

    Directory of Open Access Journals (Sweden)

    Phanish Puranam

    2015-06-01

    Full Text Available What can we learn from outliers? While statisticians rightly warn us against their non-representativeness, we believe it is also true that thinking carefully about what makes them atypical may improve our understanding of the typical case. This is the premise behind the Organization Zoo series. Valve Corporation (Valve is an unusual firm. It is a rare example of a firm that appears to operate without any formal hierarchy in its organization. What can we learn about the viability of authority hierarchies from Valve’s way of organizing? We wrote a brief account of Valve based on public information sources and asked several renowned organizational experts to comment on this unusual firm. We asked them to write a short commentary on what the Valve example means for organizational theorists and practitioners. Thankfully, they all accepted, and we are excited to present the results of their thinking in this first “exhibit” in the Organization Zoo.

  13. Multidetector CT imaging of mechanical prosthetic heart valves: quantification of artifacts with a pulsatile in-vitro model

    Energy Technology Data Exchange (ETDEWEB)

    Symersky, Petr [Onze Lieve Vrouwe Gasthuis, Department of Cardiothoracic Surgery, Oosterpark 9, P.O box 95500, Amsterdam (Netherlands); Academic Medical Center, Department of Cardiothoracic Surgery, Amsterdam (Netherlands); Budde, Ricardo P.J. [University Medical Center, Department of Radiology, Utrecht (Netherlands); Westers, Paul [Julius Center for Health Sciences and Primary Care, Department of Biostatistics, Utrecht (Netherlands); Mol, Bas A.J.M. de [Academic Medical Center, Department of Cardiothoracic Surgery, Amsterdam (Netherlands); University of Technology Eindhoven, Department of Biomedical Engineering, Eindhoven (Netherlands); Prokop, Mathias [Radboud University Nijmegen Medical Center, Department of Radiology, Nijmegen (Netherlands)

    2011-10-15

    Multidetector computed tomography (MDCT) can detect the cause of prosthetic heart valve (PHV) dysfunction but is hampered by valve-induced artifacts. We quantified artifacts of four PHV using a pulsatile in-vitro model and assessed the relation to leaflet motion and valve design. A Medtronic Hall tilting disc (MH), and Carbomedics (CM), St Jude (SJM), and ON-X bileaflet valves underwent CT in an in-vitro model using retrospective gating with a 64 detector CT system in stationary and pulsatile conditions. Artifacts and radiopaque component volumes were quantified with thresholds based on surrounding structures and valvular components. Hypodense artifacts volumes (mm{sup 3}) were 1,029 {+-} 147, 535 {+-} 53, 371 {+-} 16, and 366 {+-} 18 for the SJM, MH, CM and ON-X valves (p < 0.001 except for the latter two valves p = 0.43). Hyperdense artifact volumes were 3,546 {+-} 141, 2,387 {+-} 103, 2,003 {+-} 102, and 3,033 {+-} 31 for the SJM, MH, CM and ON-X valve, respectively (all differences p < 0.001). Leaflet motion affected hypodense (F = 41.5, p < 0.001) and hyperdense artifacts (F = 53.7, p < 0.001). Closed and moving leaflets were associated with the least and the most artifacts respectively (p < 0.001, both artifact types). Both valve design and leaflet motion affect PHV-induced artifacts. Best imaging results may be expected for the CM valve during phases in which the leaflets are closed. (orig.)

  14. 49 CFR 236.383 - Valve locks, valves, and valve magnets.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Valve locks, valves, and valve magnets. 236.383... Inspection and Tests § 236.383 Valve locks, valves, and valve magnets. Valve locks on valves of the non-cut-off type shall be tested at least once every three months, and valves and valve magnets shall...

  15. Piezoelectric valve

    Science.gov (United States)

    Petrenko, Serhiy Fedorovich

    2013-01-15

    A motorized valve has a housing having an inlet and an outlet to be connected to a pipeline, a saddle connected with the housing, a turn plug having a rod, the turn plug cooperating with the saddle, and a drive for turning the valve body and formed as a piezoelectric drive, the piezoelectric drive including a piezoelectric generator of radially directed standing acoustic waves, which is connected with the housing and is connectable with a pulse current source, and a rotor operatively connected with the piezoelectric generator and kinematically connected with the rod of the turn plug so as to turn the turn plug when the rotor is actuated by the piezoelectric generator.

  16. Excess flow shutoff valve

    Energy Technology Data Exchange (ETDEWEB)

    Kiffer, Micah S.; Tentarelli, Stephen Clyde

    2016-02-09

    Excess flow shutoff valve comprising a valve body, a valve plug, a partition, and an activation component where the valve plug, the partition, and activation component are disposed within the valve body. A suitable flow restriction is provided to create a pressure difference between the upstream end of the valve plug and the downstream end of the valve plug when fluid flows through the valve body. The pressure difference exceeds a target pressure difference needed to activate the activation component when fluid flow through the valve body is higher than a desired rate, and thereby closes the valve.

  17. Infective Endocarditis of the Aortic Valve with Anterior Mitral Valve Leaflet Aneurysm.

    Science.gov (United States)

    Tomsic, Anton; Li, Wilson W L; van Paridon, Marieke; Bindraban, Navin R; de Mol, Bas A J M

    2016-08-01

    Mitral valve leaflet aneurysm is a rare and potentially devastating complication of aortic valve endocarditis. We report the case of a 48-year-old man who had endocarditis of the native aortic valve and a concomitant aneurysm of the anterior mitral valve leaflet. Severe mitral regurgitation occurred after the aneurysm perforated. The patient showed no signs of heart failure and completed a 6-week regimen of antibiotic therapy before undergoing successful aortic and mitral valve replacement. In addition to the patient's case, we review the relevant medical literature.

  18. Vacuum Valve

    CERN Multimedia

    1974-01-01

    This valve was used in the Intersecting Storage Rings (ISR) to protect against the shock waves that would be caused if air were to enter the vacuum tube. Some of the ISR chambers were very fragile, with very thin walls - a design required by physicists on the lookout for new particles.

  19. Valve's Way

    DEFF Research Database (Denmark)

    Foss, Nicolai Juul; Dobrajska, Magdalena

    2015-01-01

    to what extent it represents a new blueprint for organization design, despite it being consistent with an “egalitarian Zeitgeist” (Puranam, 2014). In fact, managerial authority may be of increasing importance rather than the opposite (Guadalupe, Li, & Wulf, 2015). Thus, Valve is, and will remain...

  20. Valve's Way

    DEFF Research Database (Denmark)

    Foss, Nicolai Juul; Dobrajska, Magdalena

    2015-01-01

    Puranam and Håkonsson (2015) challenge us to ponder what we as organization design theorists make of Valve’s way (see also Jeppesen, 2008). We believe that Valve, in spite of its radical vision, does not represent a challenge to fundamental organization design theory and that it is questionable...

  1. Disruption of silicone valve housing in a Codman Hakim Precision valve with integrated Siphonguard.

    Science.gov (United States)

    Woerdeman, Peter A; Cochrane, David D

    2014-05-01

    Authors of this report describe 2 patients who had undergone shunt insertion for hydrocephalus and who, at 6 weeks or 9 months after their last revision, presented with symptoms of shunt dysfunction and CSF collections at the valve site. At the ensuing shunt revision in both patients, the silicone housing was fractured and the Siphonguard was disconnected from the Codman Hakim Precision flat-bottom valve. The cause of these failures was not clear since manipulation, bending, and twisting of the valves were not thought to have occurred during implantation. A review of the FDA's Manufacturer and User Facility Device Experience (MAUDE) database revealed 58 cases of silicone housing failure in the Codman Hakim Precision valve with integrated Siphonguard since the year 2000. A single report was found in the databases administered by the Canadian Medical Devices Sentinel Network (CMDSNet). The Codman Hakim Precision valves with integrated Siphonguard are delicate devices that do not withstand the intraoperative handling tolerated by other valves. When these valves are implanted, gentle handling and wide exposures are needed to minimize the risk of valve damage. Valves should be handled according to the manufacturer's instructions. However, in light of this particular pattern of failure, it is recommended that the manufacturer redesign this valve to provide handling tolerance that is characteristic of other valves on the market. The featured cases illustrate the importance of the surgeon's role in postmarket surveillance of medical devices and reporting device failures to the responsible agencies and manufacturers.

  2. Laser Doppler anemometry measurements of steady flow through two bi-leaflet prosthetic heart valves

    Directory of Open Access Journals (Sweden)

    Ovandir Bazan

    2013-12-01

    Full Text Available INTRODUCTION: In vitro hydrodynamic characterization of prosthetic heart valves provides important information regarding their operation, especially if performed by noninvasive techniques of anemometry. Once velocity profiles for each valve are provided, it is possible to compare them in terms of hydrodynamic performance. In this first experimental study using laser doppler anemometry with mechanical valves, the simulations were performed at a steady flow workbench. OBJECTIVE: To compare unidimensional velocity profiles at the central plane of two bi-leaflet aortic prosthesis from St. Jude (AGN 21 - 751 and 21 AJ - 501 models exposed to a steady flow regime, on four distinct sections, three downstream and one upstream. METHODS: To provide similar conditions for the flow through each prosthesis by a steady flow workbench (water, flow rate of 17L/min. and, for the same sections and sweeps, to obtain the velocity profiles of each heart valve by unidimensional measurements. RESULTS: It was found that higher velocities correspond to the prosthesis with smaller inner diameter and instabilities of flow are larger as the section of interest is closer to the valve. Regions of recirculation, stagnation of flow, low pressure, and flow peak velocities were also found. CONCLUSIONS: Considering the hydrodynamic aspect and for every section measured, it could be concluded that the prosthesis model AGN 21 - 751 (RegentTM is superior to the 21 AJ - 501 model (Master Series. Based on the results, future studies can choose to focus on specific regions of the these valves.

  3. Aortic valve bypass

    DEFF Research Database (Denmark)

    Lund, Jens T; Jensen, Maiken Brit; Arendrup, Henrik

    2013-01-01

    In aortic valve bypass (AVB) a valve-containing conduit is connecting the apex of the left ventricle to the descending aorta. Candidates are patients with symptomatic aortic valve stenosis rejected for conventional aortic valve replacement (AVR) or transcatheter aortic valve implantation (TAVI...

  4. Robotic mitral valve replacement.

    Science.gov (United States)

    Senay, Sahin; Gullu, Ahmet Umit; Kocyigit, Muharrem; Degirmencioglu, Aleks; Karabulut, Hasan; Alhan, Cem

    2014-01-01

    Robotic surgical techniques allow surgeons to perform mitral valve surgery. This procedure has gained acceptance, particularly for mitral valve repair in degenerative mitral disease. However, mitral repair may not always be possible, especially in severely calcified mitral valve of rheumatic origin. This study demonstrates the basic concepts and technique of robotic mitral valve replacement for valve pathologies that are not suitable for repair.

  5. Prosthetic valve endocarditis caused by Acinetobacter calcoaceticus subsp. lwoffi.

    OpenAIRE

    Weinberger, I. (Ingeburg); Davidson, E.; Rotenberg, Z; Fuchs, J; Agmon, J

    1987-01-01

    Acinetobacter spp. are uncommon etiologic agents of prosthetic valve endocarditis. Two patients with Acinetobacter calcoaceticus subsp. lwoffi prosthetic valve endocarditis are described. The patients were successfully treated with antibiotics (cefotaxime sodium and gentamicin sulfate); thus, we suggest medical treatment rather than early valve replacement in this particular type of infection.

  6. Traumatic Mitral Valve and Pericardial Injury

    Directory of Open Access Journals (Sweden)

    Nissar Shaikh

    2013-01-01

    Full Text Available Cardiac injury after blunt trauma is common but underreported. Common cardiac trauma after the blunt chest injury (BCI is cardiac contusion; it is very rare to have cardiac valve injury. The mitral valve injury during chest trauma occurs when extreme pressure is applied at early systole during the isovolumic contraction between the closure of the mitral valve and the opening of the aortic valve. Traumatic mitral valve injury can involve valve leaflet, chordae tendineae, or papillary muscles. For the diagnosis of mitral valve injury, a high index of suspicion is required, as in polytrauma patients, other obvious severe injuries will divert the attention of the treating physician. Clinical picture of patients with mitral valve injury may vary from none to cardiogenic shock. The echocardiogram is the main diagnostic modality of mitral valve injuries. Patient’s clinical condition will dictate the timing and type of surgery or medical therapy. We report a case of mitral valve and pericardial injury in a polytrauma patient, successfully treated in our intensive care unit.

  7. Automatic shutoff valve

    Science.gov (United States)

    Hawkins, S. F.; Overbey, C. W.

    1980-01-01

    Cellulose-sponge disk absorbs incoming water and expands with enough force to shut valve. When water recedes, valve opens by squeezing sponge dry to its original size. This direct mechanical action is considered more reliable than solenoid valve.

  8. Globe stability during simulated vitrectomy with valved and non-valved trocar cannulas

    Directory of Open Access Journals (Sweden)

    Abulon DJ

    2015-09-01

    Full Text Available Dina Joy Abulon,1 Martin Charles,2 Daniel E Charles21Global Medical Affairs, Alcon Laboratories, Inc., Lake Forest, CA, USA; 2Centro Oftalmológico Dr Charles, Buenos Aires, ArgentinaPurpose: To compare the effects of valved and non-valved cannulas on intraocular pressure (IOP, fluid leakage, and vitreous incarceration during simulated vitrectomy.Methods: Three-port pars plana incisions were generated in six rubber eyes using 23-, 25-, and 27-gauge valved and non-valved trocar cannulas. The models were filled with air and IOP was measured. Similar procedures were followed for 36 acrylic eyes filled with saline solution. Vitreous incarceration was analyzed in eleven rabbit and twelve porcine cadaver eyes.Results: In the air-filled model, IOP loss was 89%–94% when two non-valved cannulas were unoccupied versus 1%–5% when two valved cannulas were unoccupied. In the fluid-filled model, with non-valved cannulas, IOP dropped while fluid leaked from the open ports. With two open ports, the IOP dropped to 20%–30% of set infusion pressure, regardless of infusion pressure and IOP compensation. The IOP was maintained in valved cannulas when one or two ports were left open, regardless of IOP compensation settings. There was no or minimal fluid leakage through open ports at any infusion pressure. Direct microscopic analysis of rabbit eyes showed that vitreous incarceration was significantly greater with 23-gauge non-valved than valved cannulas (P<0.005, and endoscopy of porcine eyes showed that vitreous incarceration was significantly greater with 23-gauge (P<0.05 and 27-gauge (P<0.05 non-valved cannulas. External observation of rabbit eyes showed vitreous prolapse through non-valved, but not valved, cannulas.Conclusion: Valved cannulas surpassed non-valved cannulas in maintaining IOP, preventing fluid leakage, and reducing vitreous incarceration during simulated vitrectomy.Keywords: IOP, fluid leakage, vitreous incarceration

  9. Fatores de risco para mortalidade hospitalar no implante de prótese valvar mecânica Risk factors for hospital mortality in valve replacement with mechanical prosthesis

    Directory of Open Access Journals (Sweden)

    Mateus W De Bacco

    2009-09-01

    Full Text Available INTRODUÇÃO: A identificação dos fatores de risco pré-operatórios na cirurgia valvar visa à melhoria do resultado cirúrgico por meio da neutralização de fatores relacionados à mortalidade aumentada. Este estudo tem por objetivo identificar fatores de risco para mortalidade hospitalar em pacientes submetidos a implante de prótese valvar mecânica. MÉTODOS: Estudo prospectivo com aquisição retrospectiva de dados com 335 pacientes consecutivamente submetidos ao implante de prótese mecânica St Jude Medical, entre dezembro de 1994 e setembro de 2005, no Instituto de Cardiologia do RS, sendo 158 aórticos, 146 mitrais e 31 mitro-aórticos. Foi analisada a relação da mortalidade hospitalar com características demográficas e operatórias dos pacientes: sexo, idade, índice de massa corporal, classe funcional (NYHA, fração de ejeção, lesão valvar, hipertensão arterial sistêmica, diabete melito, creatinina, arritmia cardíaca, cirurgia cardíaca prévia, revascularização miocárdica, plastia tricúspide concomitante e caráter da cirurgia (eletivo, de urgência ou de emergência. Utilizada regressão logística para identificar os fatores de risco e quantificada sua influência pelo cálculo de odds-ratio. RESULTADOS: Ocorreram 13 (3,88% óbitos hospitalares. Características relacionadas à mortalidade aumentada foram creatinina sérica (POBJECTIVE: Identification of risk factors for cardiac surgery can improve surgical results. Our aim is to identify factors related to increased hospital mortality for patients who underwent mechanical cardiac prosthesis implant. METHODS: Prospective study with retrospective data acquirement study including 335 consecutive patients who underwent at least one implant of St. Jude Medical mechanical prosthesis between December 1994 and September 2005 at the Cardiology Institute of RS. Valve implants were 158 (47.1% in aortic position, 146 (43.6% in mitral and 31 (9.3% in aortic and mitral. The

  10. Adjustable safety relief valve

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, W.L.

    1990-06-12

    This patent describes a pressure relief valve having a relief set pressure. It comprises: a valve body having a fluid inlet and outlet, a spherical, metal valve seat associated with the inlet and a valve member comprising at least a portion of a spherical,metal ball attached to a ball holding element, the valve member being biased against the valve seat and thus providing a metal-to-metal seal preventing the passage of fluids past the valve seat when the fluid pressure in the inlet is below the relief pressure setting of the valve.

  11. Valve-in-valve-in-valve: Treating endocarditis of a transcatheter heart valve.

    Science.gov (United States)

    Nguyen, Caroline; Cheong, Adrian P; Himbert, Dominique

    2015-10-01

    Transcatheter heart valve endocarditis is a rare, but life threatening complication. We describe the case of a patient who was successfully treated by transcatheter aortic valve-in-valve-in-valve replacement with a favorable 1-year outcome, despite severe early complications.

  12. Microfluidic sieve valves

    Science.gov (United States)

    Quake, Stephen R; Marcus, Joshua S; Hansen, Carl L

    2015-01-13

    Sieve valves for use in microfluidic device are provided. The valves are useful for impeding the flow of particles, such as chromatography beads or cells, in a microfluidic channel while allowing liquid solution to pass through the valve. The valves find particular use in making microfluidic chromatography modules.

  13. Remote actuated valve implant

    Energy Technology Data Exchange (ETDEWEB)

    McKnight, Timothy E.; Johnson, Anthony; Moise, Kenneth J.; Ericson, Milton Nance; Baba, Justin S.; Wilgen, John B.; Evans, Boyd Mccutchen

    2016-05-10

    Valve implant systems positionable within a flow passage, the systems having an inlet, an outlet, and a remotely activatable valve between the inlet and outlet, with the valves being operable to provide intermittent occlusion of the flow path. A remote field is applied to provide thermal or magnetic activation of the valves.

  14. Cardiac crossroads: deciding between mechanical or bioprosthetic heart valve replacement

    Directory of Open Access Journals (Sweden)

    Maggie N Tillquist

    2011-02-01

    Full Text Available Maggie N Tillquist1, Thomas M Maddox21School of Medicine, University of Colorado Denver, Denver, CO, USA; 2VA Eastern Colorado Health Care System, and Department of Medicine (Cardiology, University of Colorado Denver, Denver, CO, USAAbstract: Nearly 15 million people in the United States suffer from either aortic or mitral valvular disease. For patients with severe and symptomatic valvular heart disease, valve replacement surgery improves morbidity and mortality outcomes. In 2009, 90,000 valve replacement surgeries were performed in the United States. This review evaluates the advantages and disadvantages of mechanical and bioprosthetic prosthetic heart valves as well as the factors for consideration in deciding the appropriate valve type for an individual patient. Although many caveats exist, the general recommendation is for patients younger than 60 to 65 years to receive mechanical valves due to the valve's longer durability and for patients older than 60 to 65 years to receive a bioprosthetic valve to avoid complications with anticoagulants. Situations that warrant special consideration include patient co-morbidities, the need for anticoagulation, and the potential for pregnancy. Once these characteristics have been considered, patients' values, anxieties, and expectations for their lifestyle and quality of life should be incorporated into final valve selection. Decision aids can be useful in integrating preferences in the valve decision. Finally, future directions in valve technology, anticoagulation, and medical decision-making are discussed.Keywords: prosthetic heart valves, patient preference, valve type, anticoagulant, structural valve deterioration 

  15. Scissor thrust valve actuator

    Science.gov (United States)

    DeWall, Kevin G.; Watkins, John C; Nitzel, Michael E.

    2006-08-29

    Apparatus for actuating a valve includes a support frame and at least one valve driving linkage arm, one end of which is rotatably connected to a valve stem of the valve and the other end of which is rotatably connected to a screw block. A motor connected to the frame is operatively connected to a motor driven shaft which is in threaded screw driving relationship with the screw block. The motor rotates the motor driven shaft which drives translational movement of the screw block which drives rotatable movement of the valve driving linkage arm which drives translational movement of the valve stem. The valve actuator may further include a sensory control element disposed in operative relationship with the valve stem, the sensory control element being adapted to provide control over the position of the valve stem by at least sensing the travel and/or position of the valve stem.

  16. Triple leaflet perforation due to endocarditis in aortic valve complicated by pneumonia and exacerbation of chronic obstructive pulmonary disease

    Directory of Open Access Journals (Sweden)

    Elton Soydan

    2015-09-01

    Full Text Available Valve perforation complicating infective endocarditis has been for decades a bad sign leading to severe valve destruction, intractable heart failure and even death if surgical therapy is not administered in time. Here we present a 57 years old male patient inadvertently diagnosed with pneumonia and chronic obstructive pulmonary disease exacerbation in another hospital. After 20 days of broad spectrum antibiotics and bronchodilator therapy no improvement was achieved. During examination a severe aortic regurgitation was recognized. Immediately after, patient was transferred to our hospital for aortic valve surgery evaluation. Transthorasic echocardiography (TTE showed a severe aortic regurgitation and vegetation like echogenicity over the noncoronary leaflet. An aortic valve replacement surgical therapy was decided. During the aortic valve excision underneath the vegetations, multiple small perforations in all the three leaflets were noticed. The destructed valve was excised and a mechanical aortic prosthesis (St Jude No: 23, MN, USA was successfully replaced. After 14 days of treatment patient was healthily discharged.

  17. [Surgical Treatment of Prosthetic Valve Endocarditis].

    Science.gov (United States)

    Kaminishi, Yuichiro; Akutsu, Hirohiko; Sugaya, Akira; Kurumisawa, Soki; Takazawa, Ippei; Sato, Hirotaka; Muraoka, Arata; Aizawa, Kei; Ohki, Shinichi; Saito, Tsutomu; Kawahito, Koji; Misawa, Yoshio

    2015-11-01

    Between 2003 and 2014, at Jichi Medical University Hospital, 11 patients with prosthetic valve endocarditis (PVE) underwent re-operation. There was 1 in-hospital death and 2 late deaths. The cause of death was cirrhosis, heart failure and sepsis, respectively. Emergency surgery, previous double valve replacement (DVR) and Staphylococcus infection were common risk factors for all 3 cases. Two cases of patients that survived who underwent mitral valve replacement (MVR) and DVR for PVE after DVR were treated with multiple antibiotic courses for bacteremia associated with hemodialysis and colon cancer. One patient who underwent DVR after mitral valve plasty which was complicated with cerebral hemorrhage, had survived and was discharged. Of the aortic PVE patients, 2 cases of aortic valve replacement (AVR) using a mechanical valve, 1 case of aortic root replacement (ARR) using a mechanical valve, and 1 ARR using the homograft, were considered cured and never relapsed. A patient with aortic PVE, who underwent AVR after cesarean section for heart failure in birth period, has received ARR twice with the mechanical valve for recurrent pseudo-aneurysm of the left ventricular outflow tract. Since hemodialysis and colon cancer is a risk factor for recurrent PVE, it is necessary to consider the long-term administration of antibiotics after surgery.

  18. Which valve is which?

    Directory of Open Access Journals (Sweden)

    Pravin Saxena

    2015-01-01

    Full Text Available A 25-year-old man presented with a history of breathlessness for the past 2 years. He had a history of operation for Tetralogy of Fallot at the age of 5 years and history suggestive of Rheumatic fever at the age of 7 years. On echocardiographic examination, all his heart valves were severely regurgitating. Morphologically, all the valves were irreparable. The ejection fraction was 35%. He underwent quadruple valve replacement. The aortic and mitral valves were replaced by metallic valve and the tricuspid and pulmonary by tissue valve.

  19. Determinants of image quality of rotational angiography for on-line assessment of frame geometry after transcatheter aortic valve implantation.

    Science.gov (United States)

    Rodríguez-Olivares, Ramón; El Faquir, Nahid; Rahhab, Zouhair; Maugenest, Anne-Marie; Van Mieghem, Nicolas M; Schultz, Carl; Lauritsch, Guenter; de Jaegere, Peter P T

    2016-07-01

    To study the determinants of image quality of rotational angiography using dedicated research prototype software for motion compensation without rapid ventricular pacing after the implantation of four commercially available catheter-based valves. Prospective observational study including 179 consecutive patients who underwent transcatheter aortic valve implantation (TAVI) with either the Medtronic CoreValve (MCS), Edward-SAPIEN Valve (ESV), Boston Sadra Lotus (BSL) or Saint-Jude Portico Valve (SJP) in whom rotational angiography (R-angio) with motion compensation 3D image reconstruction was performed. Image quality was evaluated from grade 1 (excellent image quality) to grade 5 (strongly degraded). Distinction was made between good (grades 1, 2) and poor image quality (grades 3-5). Clinical (gender, body mass index, Agatston score, heart rate and rhythm, artifacts), procedural (valve type) and technical variables (isocentricity) were related with the image quality assessment. Image quality was good in 128 (72 %) and poor in 51 (28 %) patients. By univariable analysis only valve type (BSL) and the presence of an artefact negatively affected image quality. By multivariate analysis (in which BMI was forced into the model) BSL valve (Odds 3.5, 95 % CI [1.3-9.6], p = 0.02), presence of an artifact (Odds 2.5, 95 % CI [1.2-5.4], p = 0.02) and BMI (Odds 1.1, 95 % CI [1.0-1.2], p = 0.04) were independent predictors of poor image quality. Rotational angiography with motion compensation 3D image reconstruction using a dedicated research prototype software offers good image quality for the evaluation of frame geometry after TAVI in the majority of patients. Valve type, presence of artifacts and higher BMI negatively affect image quality.

  20. A Tandem Valve, a unique complication of TAVR

    Directory of Open Access Journals (Sweden)

    Srinivasan Sattiraju

    2016-02-01

    Full Text Available , MD1*,, MD1,, MD1,, MD2, MD2,, MD, PhD3 1. Division of Cardiology, Carle Heart and Vascular Institute, Carle Hospital, Urbana, IL 2. Cardiovascular Surgery, Carle Heart and Vascular Institute, Carle Hospital, Urbana, IL 3. Division of Cardiology, University of Minnesota Medical Center, Minneapolis, MN Received: 11-1-16, Reviewed: 22-1-16, Accepted: 26-1-16 Keywords: Transcatheter aortic valve replacement, TAVR, Valve embolisation DOI: ABSTRACT We report a unique complication of transcatheter aortic valve replacement (TAVR in which there is mechanical entrapment of two Edward Sapien valves. The tandem valve con guration created a high gradient across the valves stuck in tandem. The images and videos in this case capture ndings that underscore the complexity of interaction between two prosthetic valves. We believe this case serves a high teaching value for physicians taking care of patients with aortic stenosis managed with TAVR approach.

  1. Aortic Valve Regurgitation

    Science.gov (United States)

    ... inside your heart that involves heart valves. Rheumatic fever. Rheumatic fever — a complication of strep throat and once a ... the United States — can damage the aortic valve. Rheumatic fever is still prevalent in developing countries but rare ...

  2. Pulmonary Valve Stenosis

    Science.gov (United States)

    ... growths called carcinoid tumors in the digestive system. Rheumatic fever. This complication of an infection caused by streptococcus ... valve stenosis later in life, including: Carcinoid syndrome Rheumatic fever Noonan's syndrome Mild to moderate pulmonary valve stenosis ...

  3. Aortic Valve Disease

    Science.gov (United States)

    ... Tricuspid Valve Disease Cardiac Rhythm Disturbances Thoracic Aortic Aneurysm Pediatric and Congenital Heart Disease Heart abnormalities that are ... Transplantation End-stage Lung Disease Adult Lung Transplantation Pediatric Lung ... Aortic Aneurysm Aortic Valve Disease Overview The human heart has ...

  4. Mitral Valve Stenosis

    Science.gov (United States)

    ... up around the ring around the mitral valve (annulus), which can occasionally cause mitral valve stenosis. Other ... the condition of your lungs. Transesophageal echocardiogram. A small transducer attached to the end of a tube ...

  5. Heart valve surgery

    Science.gov (United States)

    ... Tricuspid valve stenosis Risks The risks of having cardiac surgery include: Death Heart attack Heart failure Bleeding requiring ... and the A.D.A.M. Editorial team. Heart Surgery Read more Heart Valve Diseases Read more Latest ...

  6. Isolated Pulmonary Valve Endocarditis

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Hatamizadeh

    2009-06-01

    Full Text Available Infective endocarditis is one of the most severe complications of parenteral drug abuse. The outstanding clinical feature of infective endocarditis in intravenous drug abusers is the high incidence of right-sided valve infection, and the tricuspid valve is involved in 60% to 70% of the cases. We herein report a case of isolated pulmonic valve infective endocarditis with a native pulmonary valve.

  7. Aerodynamic Shutoff Valve

    Science.gov (United States)

    Horstman, Raymond H.

    1992-01-01

    Aerodynamic flow achieved by adding fixed fairings to butterfly valve. When valve fully open, fairings align with butterfly and reduce wake. Butterfly free to turn, so valve can be closed, while fairings remain fixed. Design reduces turbulence in flow of air in internal suction system. Valve aids in development of improved porous-surface boundary-layer control system to reduce aerodynamic drag. Applications primarily aerospace. System adapted to boundary-layer control on high-speed land vehicles.

  8. Heart Valve Diseases

    Science.gov (United States)

    Your heart has four valves. Normally, these valves open to let blood flow through or out of your heart, and then shut to keep it from flowing ... close tightly. It's one of the most common heart valve conditions. Sometimes it causes regurgitation. Stenosis - when ...

  9. Dump valve assembly

    Science.gov (United States)

    Owen, T.J.

    1984-01-01

    A dump valve assembly comprising a body having a bore defined by a tapered wall and a truncated spherical valve member adapted to seat along a spherical surface portion thereof against said tapered wall. Means are provided for pivoting said valve member between a closed position engagable with said tapered wall and an open position disengaged therefrom.

  10. Quadricuspid Aortic Valve

    Directory of Open Access Journals (Sweden)

    Mehmet Taşar

    2013-03-01

    Full Text Available Quadricuspid aortic valve is an extremely rare congenital defect. Isolated form appears frequently. It is seen with aortic valve regurgitation in adulthood. This case report presents a rare clinical finding of an isolated quadricuspid aortic valve with aortic regurgitation in an 64-year-old female who was referred for cardiac evaluation due to newly identified murmur.

  11. A Clinicopathological Study on Aortic Valves in Children

    Institute of Scientific and Technical Information of China (English)

    HUANG Ping; WANG Hongwei; ZHANG Zhenlu; HU Xiufen; LI Yanping; CHENG Peixuan; LIU Jianying

    2007-01-01

    In order to investigate the clinicopathological characteristics of aortic valve disease in children, all the native surgically excised aortic valves obtained between January 2003 and December 2005 were studied macroscopically and microscopically. The patients' medical records were reviewed and the clinical information was extracted. According to preoperative echocardiography, intraoperative assessment, and postoperative pathology, combined with clinical symptoms and signs, aortic valve diseases were divided into three categories: aortic stenosis (AS), aortic insufficiency (AI), and aortic stenosis with insufficiency (AS-AI). The etiology was determined according to the macroscopic, microscopic and clinical findings. The results showed that among 70 aortic valves, patient age ranged from 6 to 18 years, with a mean of 15.4 years, and there were 56 boys and 14 girts (male: female=4:1). Forty-four children only had pure aortic valve disease, and the other 26 children had aortic valve disease associated with other heart valve diseases. There were 5 cases of AS (7.14%), 60 cases of AI (85.71%) and 5 cases of AS-AI (7.14%). The causes were congenital aortic valve malformation (32 cases, 45.71%), rheumatic disease (28 cases, 40%), infective endocarditis (7 cases,10%), Marfan syndrome (2 cases, 2.86%), and undetermined (1 case, 1.43%). It was concluded that the common causes of aortic valve disease in order of frequency in children were congenital aortic valve malformation, rheumatic disease, infective endocarditis, and Marfan syndrome. AI was more common in children with aortic valve disease. Compared with adult patients, congenital bicuspid aortic valve in children was often AI. Histologically, the leaflets of congenital bicuspid aortic valve were mainly myxomatous, fibrosis and calcification less seen. AI was frequently found in rheumatic disease, mostly associated with other heart valve diseases. Macroscopic and microscopic examinations together with clinical

  12. A multicentre comparative evaluation of catheter valves.

    Science.gov (United States)

    Fader, M; Pettersson, L; Brooks, R; Dean, G; Wells, M; Cottenden, A; Malone-Lee, J

    Catheter valves are an alternative to leg bags for urine drainage, but no studies have yet been published which have compared the performance of different valves. This study was undertaken to evaluate the performance of the seven catheter valves available on the UK market in April 1996. The study was carried out by the Continence Products Evaluation (CPE) Network funded by the Medical Devices Agency (Department of Health). Each valve type was tested for 1 week by 19-36 cognitively unimpaired and manually dextrous subjects recruited from 11 test centres. At the end of each week, subjects completed an evaluation form (based on a three-point rating scale) to record product performance. The same catheter valves were also tested for ease of opening/closing by 33 subjects (mostly catheter users) who had some manual impairment. Performance scores varied widely between products. It was found that, to be successful, a valve needs to be easy to manipulate, leak-free, comfortable and inconspicuous. Prescribers need to be aware of the strengths and limitations of different valves for appropriate product selection.

  13. Main Oxidizer Valve Design

    Science.gov (United States)

    Addona, Brad; Eddleman, David

    2015-01-01

    A developmental Main Oxidizer Valve (MOV) was designed by NASA-MSFC using additive manufacturing processes. The MOV is a pneumatically actuated poppet valve to control the flow of liquid oxygen to an engine's injector. A compression spring is used to return the valve to the closed state when pneumatic pressure is removed from the valve. The valve internal parts are cylindrical in shape, which lends itself to traditional lathe and milling operations. However, the valve body represents a complicated shape and contains the majority of the mass of the valve. Additive manufacturing techniques were used to produce a part that optimized mass and allowed for design features not practical with traditional machining processes.

  14. Factors Influencing Mortality after Bioprosthetic Valve Replacement; A Midterm Outcome

    Directory of Open Access Journals (Sweden)

    Hassan Javadzadegan

    2013-12-01

    Conclusion: Our study shows that using biprosthetic valve could reduce the risk of morbidity occurrence in patient who needs valve replacement. However, if medical treatments fail, patients should be referred for surgery. This would reduce the risk of mortality because of lower incident of complications such as atrial fibrillation and morbidities due to younger patients’ population.

  15. Aortic or Mitral Valve Replacement With the Biocor and Biocor Supra

    Science.gov (United States)

    2016-03-09

    Aortic Valve Insufficiency; Aortic Valve Regurgitation; Aortic Valve Stenosis; Aortic Valve Incompetence; Mitral Valve Insufficiency; Mitral Valve Regurgitation; Mitral Valve Stenosis; Mitral Valve Incompetence

  16. JenaValve.

    Science.gov (United States)

    Treede, Hendrik; Rastan, Ardawan; Ferrari, Markus; Ensminger, Stephan; Figulla, Hans-Reiner; Mohr, Friedrich-Wilhelm

    2012-09-01

    The JenaValve is a next-generation TAVI device which consists of a well-proven porcine root valve mounted on a low-profile nitinol stent. Feeler guided positioning and clip fixation on the diseased leaflets allow for anatomically correct implantation of the device without rapid pacing. Safety and efficacy of transapical aortic valve implantation using the JenaValve were evaluated in a multicentre prospective study that showed good short and midterm results. The valve was CE-mark released in Europe in September 2011. A post-market registry ensures on-going and prospective data collection in "real-world" patients. The transfemoral JenaValve delivery system will be evaluated in a first-in-man study in the near future.

  17. Cryogenic Cam Butterfly Valve

    Science.gov (United States)

    McCormack, Kenneth J. (Inventor)

    2016-01-01

    A cryogenic cam butterfly valve has a body that includes an axially extending fluid conduit formed there through. A disc lug is connected to a back side of a valve disc and has a circular bore that receives and is larger than a cam of a cam shaft. The valve disc is rotatable for a quarter turn within the body about a lug axis that is offset from the shaft axis. Actuating the cam shaft in the closing rotational direction first causes the camming side of the cam of the cam shaft to rotate the disc lug and the valve disc a quarter turn from the open position to the closed position. Further actuating causes the camming side of the cam shaft to translate the valve disc into sealed contact with the valve seat. Opening rotational direction of the cam shaft reverses these motions.

  18. Fracturing mechanics before valve-in-valve therapy of small aortic bioprosthetic heart valves

    DEFF Research Database (Denmark)

    Johansen, Peter; Engholt, Henrik; Tang, Mariann

    2017-01-01

    AIMS: Patients with degraded bioprosthetic heart valves (BHV) who are not candidates for valve replacement may benefit from transcatheter valve-in-valve (VIV) therapy. However, at smaller sized surgical BHV the resultant orifice may become too narrow. To overcome this, the valve frame can be frac...

  19. Modeling the Mitral Valve

    Science.gov (United States)

    Kaiser, Alexander

    2016-11-01

    The mitral valve is one of four valves in the human heart. The valve opens to allow oxygenated blood from the lungs to fill the left ventricle, and closes when the ventricle contracts to prevent backflow. The valve is composed of two fibrous leaflets which hang from a ring. These leaflets are supported like a parachute by a system of strings called chordae tendineae. In this talk, I will describe a new computational model of the mitral valve. To generate geometry, general information comes from classical anatomy texts and the author's dissection of porcine hearts. An MRI image of a human heart is used to locate the tips of the papillary muscles, which anchor the chordae tendineae, in relation to the mitral ring. The initial configurations of the valve leaflets and chordae tendineae are found by solving solving an equilibrium elasticity problem. The valve is then simulated in fluid (blood) using the immersed boundary method over multiple heart cycles in a model valve tester. We aim to identify features and mechanisms that influence or control valve function. Support from National Science Foundation, Graduate Research Fellowship Program, Grant DGE 1342536.

  20. Mitral valve prolapse.

    Science.gov (United States)

    Gould, L; Gopalaswamy, C

    1984-05-01

    Mitral valve prolapse is a very common condition. It occurs in 4-5% of the population. It may be idiopathic or associated with a number of other conditions. Myxomatous degeneration is the underlying mechanism of mitral valve prolapse. Most patients with mitral valve prolapse have no symptoms. When symptoms do occur, palpitations, chest pain and dyspnea are the major complaints. The midsystolic click occasionally followed by the late systolic murmur are the typical physical findings. The echocardiogram plays a big role in the diagnosis of mitral valve prolapse. The beta blockers are used in the treatment of the symptomatic patient.

  1. Biological heart valves.

    Science.gov (United States)

    Ciubotaru, Anatol; Cebotari, Serghei; Tudorache, Igor; Beckmann, Erik; Hilfiker, Andres; Haverich, Axel

    2013-10-01

    Cardiac valvular pathologies are often caused by rheumatic fever in young adults, atherosclerosis in elderly patients, or by congenital malformation of the heart in children, in effect affecting almost all population ages. Almost 300,000 heart valve operations are performed worldwide annually. Tissue valve prostheses have certain advantages over mechanical valves such as biocompatibility, more physiological hemodynamics, and no need for life-long systemic anticoagulation. However, the major disadvantage of biological valves is related to their durability. Nevertheless, during the last decade, the number of patients undergoing biological, rather than mechanical, valve replacement has increased from half to more than three-quarters for biological implants. Continuous improvement in valve fabrication includes development of new models and shapes, novel methods of tissue treatment, and preservation and implantation techniques. These efforts are focused not only on the improvement of morbidity and mortality of the patients but also on the improvement of their quality of life. Heart valve tissue engineering aims to provide durable, "autologous" valve prostheses. These valves demonstrate adaptive growth, which may avoid the need of repeated operations in growing patients.

  2. A piezoelectrically actuated ball valve

    Science.gov (United States)

    Erwin, L. R.; Schwartz, H. W.; Teitelbaum, B. R.

    1972-01-01

    Bimorph strip composed of two layers of poled piezoelectric ceramic material closes and opens valve. Strip performs like capacitator, allowing initial inrush of current when valve is energized and then only small leakage current flows as valve remains energized.

  3. Fatores de risco hospitalar para pacientes submetidos à substituição valvar com a bioprótese porcina em instituição universitária Risk factors for hospital mortality in valve replacement with porcine bioprosthesis at an universitary institution

    Directory of Open Access Journals (Sweden)

    Ana Carolina Tieppo Fornari

    2012-12-01

    Full Text Available OBJETIVO: Identificar fatores de risco hospitalar em pacientes submetidos ao implante de bioprótese porcina no Instituto de Cardiologia do Rio Grande do Sul. MÉTODOS: Estudo retrospectivo, com informações de prontuário, de 808 pacientes submetidos ao implante de pelo menos uma bioprótese porcina St. Jude Medical Biocor, no período entre 1994 e 2009. Foi analisada a relação entre mortalidade hospitalar e características clínicas e demográficas definidas em estudos reconhecidos, visando identificar fatores de risco. Foram utilizados testes qui-quadrado, t de Student e regressão logística uni e multivariável (P 1,4 mg/dL (OR 2,28; cirurgia cardíaca prévia (OR 2,17; hipertensão arterial sistêmica (OR 1,93; classe funcional III e IV (OR 1,92; revascularização miocárdica (OR 1,81; idade > 70 anos (OR 1,80; insuficiência cardíaca congestiva (OR 1,73; e sexo feminino (OR 1,68. Pela regressão logística multivariável, para fatores independentes, identificados: lesão mitral (OR 5,29; plastia tricúspide (OR 3,07; diabete melito (OR 2,72; idade > 70 anos (OR 2,62; revascularização miocárdica (OR 2,43; cirurgia cardíaca prévia (OR 1,82; e hipertensão arterial sistêmica (OR 1,79. CONCLUSÕES: A mortalidade observada nesta casuística é compatível com literatura. Fatores de risco preponderantes são reconhecidos e devem motivar programas específicos de neutralização.OBJECTIVE: Study designed to identify characteristics of patients related to increased hospital mortality after valve replacement, assumed as risk factors. METHODS: Retrospective study including 808 patients submitted to the implant of St. Jude Biocor porcine bioprosthesis between 1994 and 2009 at Instituto de Cardiologia do Rio Grande do Sul. Primary outcome was hospital death and hospital mortality was related to demographic and surgical characteristics. Statistics include t-test, qui-square test and logistical regression analysis. RESULTS: There were 80 (9

  4. Mitral valve surgery - open

    Science.gov (United States)

    ... Saunders; 2012:chap 61. Otto CM, Bonow RO. Valvular heart disease. In: Mann DL, Zipes DP, Libby P, Bonow ... Editorial team. Related MedlinePlus Health Topics Heart Surgery Heart Valve Diseases Mitral Valve Prolapse Browse the Encyclopedia A.D. ...

  5. Blocked Urethral Valves

    Science.gov (United States)

    ... Blocked Urethral Valves Health Issues Listen Español Text Size Email Print Share Blocked Urethral Valves Page Content Article Body Urine leaves the bladder through a tube called the urethra, which in boys passes through the penis. Rarely, small membranes form across the urethra in ...

  6. Shutoff and throttling valve

    Science.gov (United States)

    Hays, L. G.

    1974-01-01

    Leaktight shutoff, precise flow control, and very low pressure drop are incorporated in all-metal valve designed for operation under extreme temperatures. Valve constructed with refractory metal is intended for control of high-temperature liquid cesium, but has applications related to control of high- and low-temperature liquids and gases.

  7. Bioprinting a cardiac valve.

    Science.gov (United States)

    Jana, Soumen; Lerman, Amir

    2015-12-01

    Heart valve tissue engineering could be a possible solution for the limitations of mechanical and biological prostheses, which are commonly used for heart valve replacement. In tissue engineering, cells are seeded into a 3-dimensional platform, termed the scaffold, to make the engineered tissue construct. However, mimicking the mechanical and spatial heterogeneity of a heart valve structure in a fabricated scaffold with uniform cell distribution is daunting when approached conventionally. Bioprinting is an emerging technique that can produce biological products containing matrix and cells, together or separately with morphological, structural and mechanical diversity. This advance increases the possibility of fabricating the structure of a heart valve in vitro and using it as a functional tissue construct for implantation. This review describes the use of bioprinting technology in heart valve tissue engineering.

  8. 国产CL-V型双叶人工心脏瓣膜与进口St.Jude双叶瓣的临床疗效比较%Comparison on Clinical Outcomes Between China-made CL-V Bileaflet Prosthesis and St.Jude Bileaflet Prosthesis

    Institute of Scientific and Technical Information of China (English)

    祁亮; 宋兵; 刘瑞生; 唐汉博; 赵宏林; 邢旺; 高百顺

    2012-01-01

    Objective To evaluate early clinical outcomes and short-term follow-up results of CL-V bileaflet prosthesis. Methods From April 2004 to May 2010, 38 patients with valvular heart diseases underwent mechanical heart valve replacement. Eighteen patients received CL-V bileaflet valve replacement (CL group) including 8 males and 10 females with their mean age of (47. 4 ±6. 2) years and mean body weight off 64. 7±11. 9) kg. Preoperatively, 15 patients were in New York Heart Association (NYHA) class Ⅲ, and 2 patients were in NYHA class IV. Mitral valve replacement (MVR) was performed in 16patients, mitral and aortic valve replacement (DVR) in 2 patients. A total of 20 CL-V bileaflet prostheses were implanted. Twenty patients received St. Jude bileaflet valve replacement (SJM group Kncluding 9 males and 11 females with their mean age of (49. 7±7. 6) years and mean body weight of (66. 1±11. 1) kg. Preoperatively,15 patients were in NYHA class Ⅲ, and 3 patients were in NYHA class Ⅳ . MVR was performed in 17 patients, aortic valve replacement (AVR) in 1 patient, and DVR in 2 patients. A total of 22 St. Jude bileaflet prostheses were implanted. Clinical outcomes, hear function, hemodynamics and blood compatibility were measured on the 7th postoperative day and 6 months during follow-up and compared between the two groups. Results There was no early mortality ( < 30 d) or postoperative complication in either group. Follow-up rate was 100% and the mean follow-up duration was 19. 8 (6-61) months. At 6 months after surgery, those patients who were preoperatively in NYHA class Ⅲ or Ⅳall improved to class Ⅰ orⅡ. In CL group, cardiothoracic ratio was 0. 51±0. 05, left atrium diameter (44. 5±7. 8) mm, left ventricular end dias-tolic diameter (LVEDD, 46. 6±4.1) mm, LVEF 65. 3%±7. 7%, and LVFS 35. 0%±7. 1%. In SJM group, cardiothoracic ratio was 0. 51±0. 06, left atrium diameter(45. 8±9. 6)mm, LVEDD(46. 2±9. 8) mm, LVEF 64. l%+9. 0%, and LVFS 34. 9%±4. 7

  9. Midterm evaluation of hemodynamics of the Top Hat supraannular aortic valve

    DEFF Research Database (Denmark)

    Aagaard, Jan; Nissen, Henrik; Geha, Alexander S

    2010-01-01

    The CarboMedics Top Hat supraannular aortic valve provides an orifice-to-annulus ratio of 1:1 in most patients, and enhances patient outcomes. This study compared the midterm echocardiographic parameters of 52 patients undergoing aortic valve replacement with a Top Hat valve with those in other...... measurements were compared in 38 patients with aortic valve stenosis. Hemodynamic data were comparable to those of other studies, but the Top Hat prosthesis implanted was significantly larger (by a mean of 3.29 mm) than the valve size indicated using an intraannular valve sizer in 48 patients. Mean effective...... orifice area improved significantly from 0.73 cm(2) preoperatively to 2.04 cm(2) postoperatively. In patients with preoperative aortic valve stenosis, postoperative mean peak gradient was significantly reduced. The larger orifice-to-annulus ratio of the Top Hat valve improved hemodynamic parameters...

  10. Face-Sealing Butterfly Valve

    Science.gov (United States)

    Tervo, John N.

    1992-01-01

    Valve plate made to translate as well as rotate. Valve opened and closed by turning shaft and lever. Interactions among lever, spring, valve plate, and face seal cause plate to undergo combination of translation and rotation so valve plate clears seal during parts of opening and closing motions.

  11. Double Valve Replacement for Lupus Valvulitis

    Science.gov (United States)

    Ferraris, Victor A.; Hawksley, Vaughn C.; Rabinowitz, Max; Coyne, Carolyn M.; Sullivan, Thomas J.; Sprague, Merle S.

    1990-01-01

    Hemodynamically significant lupus valvulitis, requiring valve replacement, is rare: 21 cases have been reported so far in the literature, and only 2 of these have involved double valve replacement. We describe an additional case of double valve replacement in a patient with systemic lupus erythematosus. The histopathologic and clinical features of this case suggest that valvular involvement resulted from both acute and chronic disease processes. Medical success in the treatment of systemic lupus erythematosus, especially that achieved through prolonged or high-dose steroid therapy, may cause chronic valvular disease to become a more common surgical problem. A review of the literature supports this contention. (Texas Heart Institute Journal 1990;17:56-60) Images PMID:15227191

  12. Mesofluidic two stage digital valve

    Energy Technology Data Exchange (ETDEWEB)

    Jansen, John F; Love, Lonnie J; Lind, Randall F; Richardson, Bradley S

    2013-12-31

    A mesofluidic scale digital valve system includes a first mesofluidic scale valve having a valve body including a bore, wherein the valve body is configured to cooperate with a solenoid disposed substantially adjacent to the valve body to translate a poppet carried within the bore. The mesofluidic scale digital valve system also includes a second mesofluidic scale valve disposed substantially perpendicular to the first mesofluidic scale valve. The mesofluidic scale digital valve system further includes a control element in communication with the solenoid, wherein the control element is configured to maintain the solenoid in an energized state for a fixed period of time to provide a desired flow rate through an orifice of the second mesofluidic valve.

  13. Aortic valve replacement

    DEFF Research Database (Denmark)

    Kapetanakis, Emmanouil I; Athanasiou, Thanos; Mestres, Carlos A

    2008-01-01

    BACKGROUND AND AIMS OF THE STUDY: Prompted by anecdotal evidence and observations by surgeons, an investigation was undertaken into the potential differences in implanted aortic valve prosthesis sizes, during aortic valve replacement (AVR) procedures, between northern and southern European...... countries. METHODS: A multi-institutional, non-randomized, retrospective analysis was conducted among 2,932 patients who underwent AVR surgery at seven tertiary cardiac surgery centers throughout Europe. Demographic and perioperative variables including valve size and type, body surface area (BSA) and early...

  14. GIANT PROSTHETIC VALVE THROMBUS

    Directory of Open Access Journals (Sweden)

    Prashanth Kumar

    2015-04-01

    Full Text Available Mechanical prosthetic valves are predisposed to bleeding, thrombosis & thromboembolic complications. Overall incidence of thromboembolic complications is 1% per year who are on oral anticoagulants, whereas bleeding complications incidence is 0.5% to 6.6% per year. 1, 2 Minimization of Scylla of thromboembolic & Charybdis of bleeding complication needs a balancing act of optimal antithrombotic therapy. We are reporting a case of middle aged male patient with prosthetic mitral valve presenting in heart failure. Patient had discontinued anticoagulants, as he had subdural hematoma in the past. He presented to our institute with a giant prosthetic valve thrombus.

  15. Danfos: Thermostatic Radiator Valves

    DEFF Research Database (Denmark)

    Gregersen, Niels; Oliver, James; Hjorth, Poul G.

    2000-01-01

    This problem deals with modelling the flow through a typical Danfoss thermostatic radiator valve.Danfoss is able to employ Computational Fluid Dynamics (CFD) in calculations of the capacity of valves, but an experienced engineer can often by rules of thumb "guess" the capacity, with a precision...... similar to the one achieved by the expensive and time-consuming CFD calculations. So CFD is only used in case of entirely new designs or where a very detailed knowledge of the flow is required. Even though rules of thumb are useful for those, who have developed them, Danfoss needs an objective and general...... method that can be used to predict the performance of valves....

  16. A valve disk

    Energy Technology Data Exchange (ETDEWEB)

    Khayrullin, N.A.; Isayev, B.N.; Kruglov, S.A.; Molokanov, Yu.K.; Shchelkunov, V.A.; Shegay, V.R.; Vizhgorodskiy, B.N.

    1982-01-01

    A valve disk is proposed which includes a horizontal bed, on which there are laminar valves arranged in staggered order. To ensure the stable and effective operation of the disk in a broad range of loads by compensating for the direct flow and the partial sectioning of the disk bed, it is equipped with compensating elements installed in openings in the bed and hinged with it. They are made in the form of straight, triangular prisms with ports in the bases. The prisms are installed with the capability of movement relative to the disk bed. The valves are positioned on the upper lateral facets of the compensating elements.

  17. Treatment Outcomes in Black and White Children With Cancer: Results From the SEER Database and St Jude Children's Research Hospital, 1992 Through 2007

    Science.gov (United States)

    Pui, Ching-Hon; Pei, Deqing; Pappo, Alberto S.; Howard, Scott C.; Cheng, Cheng; Sandlund, John T.; Furman, Wayne L.; Ribeiro, Raul C.; Spunt, Sheri L.; Rubnitz, Jeffrey E.; Jeha, Sima; Hudson, Melissa M.; Kun, Larry E.; Merchant, Thomas E.; Kocak, Mehmet; Broniscer, Alberto; Metzger, Monika L.; Downing, James R.; Leung, Wing; Evans, William E.; Gajjar, Amar

    2012-01-01

    Purpose Treatment outcome for black patients with cancer has been significantly worse than for their white counterparts. We determined whether recent improved treatment had narrowed the gap in outcome between black and white pediatric patients. Patients and Methods In a parallel comparison, we analyzed survival by disease category between black and white patients with childhood cancer registered in one of the 17 cancer registries of the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program or treated at St Jude Children's Research Hospital, which provides comprehensive treatment to all patients regardless of their ability to pay, from 1992 to 2000 and from 2001 to 2007. Results Analysis of the SEER data indicated that in both study periods, black patients had significantly poorer rates of survival than did white patients, with the exception of a few types of cancer. Despite significantly improved treatment outcomes for patients who were treated from 2001 to 2007, the racial difference in survival has actually widened for acute myeloid leukemia and neuroblastoma. By contrast, in the cohorts treated at St Jude Children's Research Hospital, there were no significant differences in survival between black and white patients in either study period, regardless of the cancer type. Importantly, the outcome of treatment for acute lymphoblastic leukemia, acute myeloid leukemia, and retinoblastoma has improved in parallel for both races during the most recent study period. Conclusion With equal access to comprehensive treatment, black and white children with cancer can achieve the same high cure rates. PMID:22547602

  18. Automatic measuring of quality criteria for heart valves

    Science.gov (United States)

    Condurache, Alexandru Paul; Hahn, Tobias; Hofmann, Ulrich G.; Scharfschwerdt, Michael; Misfeld, Martin; Aach, Til

    2007-03-01

    Patients suffering from a heart valve deficiency are often treated by replacing the valve with an artificial or biological implant. In case of biological implants, the use of porcine heart valves is common. Quality assessment and inspection methods are mandatory to supply the patients (and also medical research) with only the best such xenograft implants thus reducing the number of follow-up surgeries to replace worn-up valves. We describe an approach for automatic in-vitro evaluation of prosthetic heart valves in an artificial circulation system. We show how to measure the orifice area during a heart cycle to obtain an orifice curve. Different quality parameters are then estimated on such curves.

  19. Surgical double valve replacement after transcatheter aortic valve implantation and interventional mitral valve repair.

    Science.gov (United States)

    Wendeborn, Jens; Donndorf, Peter; Westphal, Bernd; Steinhoff, Gustav

    2013-11-01

    Transcatheter aortic valve implantation, as well as interventional mitral valve repair, offer reasonable therapeutic options for high-risk surgical patients. We report a rare case of early post-interventional aortic valve prosthesis migration to the left ventricular outflow tract, with paravalvular leakage and causing severe mitral valve regurgitation. Initial successful interventional mitral valve repair using a clipped edge-to-edge technique revealed, in a subsequent procedure, the recurrence of mitral valve regurgitation leading to progressive heart failure and necessitating subsequent surgical aortic and mitral valve replacement.

  20. Mitral Valve Disease

    Science.gov (United States)

    ... for more information on procedures, news, and pre- & post-operative care. Section Navigation Select Topic Aortic Valve Disease ... is most commonly caused by inflammation from rheumatic fever, a disease that is related to strep infections; ...

  1. Valve Repair or Replacement

    Science.gov (United States)

    ... valve surgery can be done using a robot. Robotic surgery does not require a large incision in the ... The Texas Heart Institute has a robot. With robotic surgery, the surgeon has a control console, a side ...

  2. Pulmonary valve stenosis

    Science.gov (United States)

    ... valvuloplasty - pulmonary Images Heart valves References Carabello BA. Valvular heart disease. In: Goldman L, Schafer AI, eds. Goldman's Cecil ... Saunders; 2016:chap 69. Otto CM, Bownow RO. Valvular heart disease. In: Mann DL, Zipes DP, Libby P, Bonow ...

  3. Mitral valve regurgitation

    Science.gov (United States)

    ... and dentist if you have a history of heart valve disease or congenital heart disease before treatment. Some people ... the middle Heart, front view References Carabello BA. Valvular heart disease. In: Goldman L, Schafer AI, eds. Goldman's Cecil ...

  4. Mitral Valve Prolapse

    Science.gov (United States)

    ... Kawasaki Disease Long Q-T Syndrome Marfan Syndrome Metabolic Syndrome Mitral Valve Prolapse Myocardial Bridge Myocarditis Obstructive Sleep Apnea Pericarditis Peripheral Vascular Disease Rheumatic Fever Sick Sinus Syndrome Silent Ischemia Stroke Sudden ...

  5. 心脏机械瓣膜置换术后华法林低强度抗凝疗效观察%Efficacy of warfarin low intense anticoagulation after heart valve replacement

    Institute of Scientific and Technical Information of China (English)

    刘状; 葛圣林; 张成鑫

    2014-01-01

    anticoagulation at the 1st Affiliated Hospital of Anhui Medical University from January 2010 to January 2013 .During the follow-up,we recorded the prothrombin time ( PT) ,international normalized ratio ( INR) and oral war-farin dose and thromboembolism/hemorrhage complications .Results Complete data were obtained of 469 patients which were followed up for an average of 18.13 ±6.02 months (range 1~37 months),totally followed up 1 960.8p-ys.Two hundred and eleven were males and two hundred and fifty-eight were females with a mean age of 40.52 ±13.38 years.A total of 268 patients had MVR,115 patients AVR,and 86 patients DVR.Valves implanted were all bileaflet ,of which 153 were St.Jude Regent,291 CarboMedics,and 111 GKS. Average INR was 2.11 ±0.56,and warfarin dose was (3.124 ±2.4) mg.There were 47 cases of anticoagulation-related complications ,of which 37 were anticoagulation-related hemorrhage (1.89%pt-y),and 10 were anticoagulation-related thromboembolism (0.51%pt-y). And 5 patients died,of which 3 were anticoagulation related .Among all of these patients ,316 were complicated by atrial fibrillation and 43 by left atrial thrombosis .Conclusions Anticoagulation for mechanical heart valve replacement can be managed with INR levels within the range of 1.8~2.2 ,which can prevent hemorrhagic and thromboembolic events .Patients with atrial fibrillation and double valve replace-ment have higher anticoagulation-related morbidity ,which should have higher frequency of review and timely adjustment of warfarin dose .

  6. A Tandem Valve, a unique complication of TAVR

    OpenAIRE

    Srinivasan Sattiraju; Sanjay Mehta; Mathew Gibb; Scott Cook; Michael Colla; Emil Missov

    2016-01-01

    , MD1*,, MD1,, MD1,, MD2, MD2,, MD, PhD3 1. Division of Cardiology, Carle Heart and Vascular Institute, Carle Hospital, Urbana, IL 2. Cardiovascular Surgery, Carle Heart and Vascular Institute, Carle Hospital, Urbana, IL 3. Division of Cardiology, University of Minnesota Medical Center, Minneapolis, MN Received: 11-1-16, Reviewed: 22-1-16, Accepted: 26-1-16 Keywords: Transcatheter aortic valve replacement, TAVR, Valve embolisation DOI: ABSTRACT We report a unique complica...

  7. Implantation of the CoreValve percutaneous aortic valve.

    Science.gov (United States)

    Lamarche, Yoan; Cartier, Raymond; Denault, André Y; Basmadjian, Arsène; Berry, Colin; Laborde, Jean-Claude; Bonan, Raoul

    2007-01-01

    Surgical aortic valve replacement is the only recommended treatment for significant aortic valve stenosis. Percutaneous aortic valve replacement appears to be a novel option for high-risk patients. We report the implantation of the ReValving system (CoreValve, Paris, France) in a 64-year-old woman who was refused aortic valve replacement surgery for critical aortic stenosis and left ventricular dysfunction because of severe pulmonary fibrosis. After anesthesia, the patient was put on femorofemoral cardiopulmonary bypass, and underwent a balloon valvuloplasty with subsequent retrograde aortic valve replacement by the ReValving system. Transesophageal echocardiographic monitoring of the patient's hemodynamics showed immediate improvements of the valvular area and left ventricular ejection fraction and only traces of paravalvular leaks. The patient was easily weaned from ventilation and resumed activity soon after the surgery. A multidisciplinary approach is presently necessary to offer a reliable and safe procedure.

  8. [Technologies for cardiac valve prostheses].

    Science.gov (United States)

    Nakano, Kiyoharu

    2009-07-01

    To show the technological development of cardiac valve prostheses, a historical review of both mechanical and biological valve prostheses and a current overview of modern cardiac valve devices are provided. Scince the 1st implantation of Starr-Edwards ball valve in 1960, both mechanical and biological valve prostheses have advanced. The valve design, the material of the leaflet and the hausing of mechanical prostheses have improved. Currently, the majority of the mechanical prostheses are bileaflet tilting disc valves made of pyrolytic carbon, which is antithromboembolic. However, anticoagulation therapy with warfarin is still required. As for the bioprostheses, although the fixation and anti-mineralization methods of the tissues improved, the durability of these valves is still limited. For the material of the current biological valves, the porcine aortic valve or bovine pericardium are used. The tissues are fixed by non-pressure or low-pressure method in glutaraldehyde solution. A stented and non-stented valves are available. Epoch-making events in this field are the implantation of new bioprosthetic valves using tissue engineering methods and the development of the transcatheter valve replacement therapies.

  9. Transcatheter Aortic Valve Replacement for Degenerative Bioprosthetic Surgical Valves

    DEFF Research Database (Denmark)

    Dvir, Danny; Webb, John; Brecker, Stephen;

    2012-01-01

    Transcatheter aortic valve-in-valve implantation is an emerging therapeutic alternative for patients with a failed surgical bioprosthesis and may obviate the need for reoperation. We evaluated the clinical results of this technique using a large, worldwide registry.......Transcatheter aortic valve-in-valve implantation is an emerging therapeutic alternative for patients with a failed surgical bioprosthesis and may obviate the need for reoperation. We evaluated the clinical results of this technique using a large, worldwide registry....

  10. Mitral Valve Aneurysm: A Rare Complication of Aortic Valve Endocarditis

    Directory of Open Access Journals (Sweden)

    A Moaref

    2008-11-01

    Full Text Available A 20-year-old intravenous drug abuser man, refered to our hospital with dyspnea and orthopnea. Tranesophagealechocardiography revealed severe aortic regurgitation, healed vegetation of aortic valve and an aneurysm of theanterior leaflet of the mitral valve. The patient was discharged after aortic valve replacement and mitral valverepair.

  11. Research on Valve Body Design of Large Bore Sodium Valve

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Large bore sodium valve is one kind of key equipments of China Demonstration Fast Reactor (CDFR). It is installed in the pipeline before and behind SG units as a locking mechanism. Valve body which is used to bear pressure is the core of sodium valve design.

  12. Transcatheter Aortic Heart Valve Thrombosis

    DEFF Research Database (Denmark)

    Hansson, Nicolaj C; Grove, Erik L; Andersen, Henning R;

    2016-01-01

    BACKGROUND: There is increasing focus on transcatheter heart valve (THV) thrombosis. However, there are limited data on incidence, clinical implications and predisposing factors of THV thrombosis following transcatheter aortic valve replacement (TAVR). OBJECTIVES: We assessed the incidence...

  13. Safety valve for offshore borehole

    Energy Technology Data Exchange (ETDEWEB)

    McGill, H.L.; Randermann, E. Jr.; Musik, O.J.

    1977-10-06

    The invention concerns a new and improved submarine safety valve with a valve element which rotate, which can be used, in emergencies, to separate the wound-up piping which extends into the borehole and to close the production line.

  14. Nasal valve surgery.

    Science.gov (United States)

    Apaydin, Fazil

    2011-04-01

    Nasal obstruction can be due to internal and external valve problems that can be seen before and after rhinoplasty. The main scope of this article is to concentrate on surgical solutions to these problems. To overcome nasal obstruction at the internal valve, spreader grafts, spreader flaps, upper lateral splay graft, butterfly graft, flaring suture, M-plasty, Z-plasty, and suspension sutures have been described. The management of the external valve problems is possible by using lateral crural dissection and repositioning, lateral crural strut grafts, alar battens, lateral crural turn-in flap, alar rim grafts, and various other methods. It is not easy to decide which techniques would work best in every case. After a thorough examination and analysis, the underlying cause of the nasal obstruction can be understood, and one or multiple procedures can be chosen according to each individual problem.

  15. Percutaneous mitral valve repair.

    Science.gov (United States)

    Gillinov, A Marc; Liddicoat, John R

    2006-01-01

    Surgical mitral valve repair is the procedure of choice to treat mitral regurgitation of all etiologies. Whereas annuloplasty is the cornerstone of mitral valve repair, a variety of other surgical techniques are utilized to correct dysfunction of the leaflets and subvalvular apparatus; in most cases, surgical repair entails application of multiple repair techniques in each patient. Preclinical studies and early human experience have demonstrated that some of these surgical repair techniques can be performed using percutaneous approaches. Specifically, there has been great progress in the development of novel technology to facilitate percutaneous annuloplasty and percutaneous edge-to-edge repair. The objectives of this report were to (1) discuss the surgical foundations for these percutaneous approaches; (2) review device design and experimental and clinical results of percutaneous valve repair; and (3) address future directions, including the key challenges of patient selection and clinical trial design.

  16. Plastik på trikuspidalklappen (Tricuspid valve annuloplasty. The neglected valve)

    DEFF Research Database (Denmark)

    Pedersen, Thais A L; Wierup, Per; Pedersen, Lia Mendes;

    2010-01-01

    INTRODUCTION: Tricuspid valve regurgitation (TVR) is often secondary to left-sided or congenital heart disease (CHD). Surgical correction of TVR is indicated when the primary abnormalities require operation. MATERIAL AND METHODS: Retrospective analysis of all 50 patients (mean age: 65 years (range......: 24-83), 27 males, 23 females) operated with tricuspid valve annuloplasty (TVA) in our hospital from 2000 to 2007. TVA took place concomitantly with operation for left heart disease (n = 39, 78%) or CHD (n = 11, 22%). RESULTS: Preoperatively, TVR was severe in 40, moderate in six and mild in four....... There were five (10%) early and two (4%) late deaths. Temporary arrhythmias requiring medical treatment occurred in 35 cases, but eight required permanent pacemaker. No tricuspid valve reoperations were performed. CONCLUSIONS: The combination of correction of primary heart abnormalities and TVA is associated...

  17. Misty Life: Nihilism in Jude the Obscure%迷雾人生——《无名的裘德》中的虚无主义

    Institute of Scientific and Technical Information of China (English)

    杨丽

    2011-01-01

    Jude the Obscure is the last novel of Thomas Hardy. It is a destructive novel and expresses the idea of nihility. Jude, Sue, Arabella and Phillotson could not have real happiness. The failed career, unhappy marriage, and fragile life are as misty as the fog. The consciousness of dream, loneliness and death through career, marriage and life, and the image of fog all are related with nihility. Returning to Christ is not the real way out for redemption of tragedy and nihility.%《无名的裘德》作为哈代的封山之作,是一部不折不扣的毁灭文学。小说的很多地方都体现了虚无主义,不管是裘德、艾拉白拉、淑,还是费劳孙和小时光老人,都没能拥有实实在在的幸福,事业不得志,爱情不幸福,生命终究灰飞烟灭,一切都如雾一般飘渺。小说在事业、感情、生命方面体现出来的梦幻意识、孤独意识和死亡意识,以及虚无意象“雾”的描写,都与虚无主义有着密切的联系。在悲剧和虚无中,对基督教信仰的回归并不是救赎之道。

  18. Building valve amplifiers

    CERN Document Server

    Jones, Morgan

    2013-01-01

    Building Valve Amplifiers is a unique hands-on guide for anyone working with tube audio equipment--as an electronics hobbyist, audiophile or audio engineer. This 2nd Edition builds on the success of the first with technology and technique revisions throughout and, significantly, a major new self-build project, worked through step-by-step, which puts into practice the principles and techniques introduced throughout the book. Particular attention has been paid to answering questions commonly asked by newcomers to the world of the valve, whether audio enthusiasts tackling their first build or

  19. SAFETY SHUTOFF VALVE

    DEFF Research Database (Denmark)

    2010-01-01

    It is disclosed a shut-off valve which acts automatically and has a fully mechanical performance with respect to the loosing of the tower-shape part balance under the effect of the special acceleration Which is arisen from the quakes waves or serious vibrations, while such vibrations are mainly...... resulted from collision or effusion. A static tower has been applied for the main core of this part of the valve which loses balance state under the effect of collision and bounces to the neighboring part, which results in release of the catch and blockage of the gas passing channel....

  20. Pulsatile prosthetic valve flows.

    Science.gov (United States)

    Phillips, W M; Snyder, A; Alchas, P; Rosenberg, G; Pierce, W S

    1980-01-01

    The laser Doppler system has been established as a useful tool for eliciting the properties of simulated cardiovascular flows, and thus for comparative studies of flow properties of prosthetic valves. Significant differences among valve types and between models of one type have been documented. The complex variations of velocity profiles with time show that comparisons must be made for unsteady pulsatile rather than steady flow, despite the volume and complexity of the data required. Future studies will include methods of compacting the data presentation and improving the details of the experimental stimulation.

  1. Valve stem and packing assembly

    Energy Technology Data Exchange (ETDEWEB)

    Wordin, J.J.

    1990-12-31

    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele`s pivot. The Schiele`s pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele`s pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele`s pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.

  2. Transcatheter Valve-in-Valve: A Cautionary Tale.

    Science.gov (United States)

    Luc, Jessica G Y; Shanks, Miriam; Tyrrell, Benjamin D; Welsh, Robert C; Butler, Craig R; Meyer, Steven R

    2016-09-01

    Transcatheter aortic valve replacement (TAVR) by valve-in-valve (VIV) implantation is an alternative treatment for high-risk patients with a degenerating aortic bioprosthesis. We present a case of transapical TAVR VIV with a 29-mm Edwards SAPIEN XT (ESV) (Edwards Lifesciences, Irvine, CA) into a 29-mm Medtronic Freestyle stentless bioprosthesis (Medtronic Inc, Minneapolis, MN) in which unanticipated dilatation of the Freestyle bioprosthesis resulted in intraprocedural embolization of the TAVR valve, necessitating urgent conversion to a conventional surgical aortic valve replacement (AVR). Our experience suggests that TAVR VIV with the 29-mm ESV in the setting of a degenerated 29-mm Freestyle stentless bioprosthesis must be undertaken with caution.

  3. Aortic valve surgery: what is the future?

    Science.gov (United States)

    Hudorović, Narcis

    2008-04-01

    Modern surgical treatment for aortic valve disease has undergone significant improvements in all areas of this procedure. Successful treatment strategies for cardiovascular diseases have often been initiated and driven by surgeons. Radical excision of diseased tissue, repair and replacement strategies lead to long-term successful treatment of the underlying diseases and clearly improved patient outcome. In highly developed nations, valve surgery will be increasing applied in older people, with more co-morbidities and a higher incidence of concomitant coronary artery disease. Cardiovascular surgeons will be facing increased competition from the catheter-based procedures; these are already applied clinically, and their numbers will rise in near future. Right now interventional cardiologists supported by some cardiac surgeons are on their way to transform some conventional open surgical procedures into catheter-based less invasive interventions, such as valve repair and replacement. Cardiovascular surgery is undergoing a rapid transformation; socio-economic factors and recent advances in medical technology contribute to these changes. Further developments will come, and surgeons with all their expertise in the treatment of valvular heart disease need to be part of it. Cardiovascular surgeons have to adapt the exciting new approaches of transapical and transfemoral transcatheter valve implantation techniques.

  4. Prosthetic valve thrombosis in a patient with mitral valve replacement.

    Science.gov (United States)

    Bilal, Muhammad; Khan, Muhammad Shahzeb; Haseeb, Abdul; Khan, Abdul Bari

    2015-07-01

    Prosthetic valve thrombosis within one year after mitral valve replacement is rarely seen in patients on warfarin therapy and without any risk factor. Here, we describe a case of a 39-year- old female, who presented with dyspnoea and shortness of breath 11 months after mitral valve replacement. The echocardiogram revealed severe valvular stenosis due to presence of clots on the mitral valve and restricted motion of the mitral leaflets. As a result of deterioration of general condition and haemodynamic un-stability, plan was made to re-operate for her valve replacement surgery. This case report highlights the diagnosis, prevention and management of patients with prosthetic valve thrombosis following mitral valve replacement.

  5. Congenital quadricuspid aortic valve: analysis of 11 surgical cases

    Institute of Scientific and Technical Information of China (English)

    TANG Yang-feng; XU Ji-bin; HAN Lin; LU Fang-lin; LANG Xi-long; SONG Zhi-gang; XU Zhi-yun

    2011-01-01

    Background Congenital quadricuspid aortic valve is rarely seen during aortic valve replacement (AVR).The diagnosis and treatment of the disease were reported in 11 cases.Methods Eleven patients (nine men and two women,mean age 33.4 years) with quadricuspid aortic valve were retrospectively evaluated.Medical records,echocardiograms and surgical treatment were reviewed.Results In accordance with the Hurwitz and Roberts classification,the patients were classified as type A (n=2),type B (n=7),type F (n=1) and type G (n=1).Three patients were associated with other heart diseases,including infective endocarditis and mitral prolaps,left superior vena cava,aortic aneurysm.All had aortic regurgitation (AR) except two with aortic stenosis (AS),detected by color-flow Doppler echocardiography.The congenital quadricuspid aortic valve deformity in seven patients was diagnosed by echocardiography.All patients underwent successful aortic valve replacement.Conclusion Quadricuspid aortic valve is a rare cause of aortic insufficiency,while echocardiography plays an important role in diagnosing the disease.Aortic valve replacement is the major therapy for the disease.

  6. Distortion of the CoreValve during transcatheter aortic valve-in-valve implantation due to valve dislocation

    Energy Technology Data Exchange (ETDEWEB)

    Souteyrand, Geraud, E-mail: gsouteyrand@chu-clermontferrand.fr [Department of Cardiology, Gabriel Montpied Hospital, CHU Clermont-Ferrand, Clermont-Ferrand (France); ERIM-EA3295, University of Auvergne, Clermont-Ferrand (France); Wilczek, Krzysztof [Department of Cardiology, Medical University of Silesia, Silesian Centre for Herat Diseases, Zabrze (Poland); Innorta, Andrea; Camilleri, Lionel [Department of Cardiology, Gabriel Montpied Hospital, CHU Clermont-Ferrand, Clermont-Ferrand (France); ERIM-EA3295, University of Auvergne, Clermont-Ferrand (France); Chodor, Piotr [Department of Cardiology, Medical University of Silesia, Silesian Centre for Herat Diseases, Zabrze (Poland); Lusson, Jean-René; Motreff, Pascal [Department of Cardiology, Gabriel Montpied Hospital, CHU Clermont-Ferrand, Clermont-Ferrand (France); ERIM-EA3295, University of Auvergne, Clermont-Ferrand (France); Laborde, Jean-Claude [St. George' s Hospital, London (United Kingdom); Chabrot, Pascal; Durel, Nicolas [Department of Cardiology, Gabriel Montpied Hospital, CHU Clermont-Ferrand, Clermont-Ferrand (France); ERIM-EA3295, University of Auvergne, Clermont-Ferrand (France)

    2013-09-15

    Nowadays transcatheter aortic valve implantation (TAVI) is an accepted alternative to surgical aortic valve replacement for high-risk patients (pts). Successful TAVI procedures for failed aortic surgical bioprosthesis (TAV-in-SAV) have already been reported. In the presented two cases of TAV-in-SAV implantation a strut distortion of the stent was revealed on angiographic imaging and confirmed on control CT scan. In both procedures, a dislocation of the medtronic core valve (MCV) prosthesis during implantation led to valve retrieval, with a necessity of reloading it in the 18F introducer before subsequent implantation of the same valve in correct position.

  7. An electrochemical active valve

    NARCIS (Netherlands)

    Neagu, C.R.; Gardeniers, J.G.E.; Elwenspoek, M.; Kelly, J.J.

    1997-01-01

    A novel electrochemical microactuator was developed, which operates as an active valve. The microactuator consists of an electrochemical cell and a membrane that deflects because of the pressure of oxygen gas generated by electrolysis. Relatively large pressures (up to tens of bars) can be reached w

  8. Thermostatic Radiator Valve Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Dentz, J.; Ansanelli, E.

    2015-01-01

    A large stock of multifamily buildings in the Northeast and Midwest are heated by steam distribution systems. Losses from these systems are typically high and a significant number of apartments are overheated much of the time. Thermostatically controlled radiator valves (TRVs) are one potential strategy to combat this problem, but have not been widely accepted by the residential retrofit market.

  9. Heart valve surgery - discharge

    Science.gov (United States)

    ... ACC guideline for the management of patients with valvular heart disease: executive summary: a report of the American College ... Editorial team. Related MedlinePlus Health Topics Heart Surgery Heart Valve Diseases Browse the Encyclopedia A.D.A.M., Inc. ...

  10. Aortic valve surgery - open

    Science.gov (United States)

    ... Saunders; 2012:chap 61. Otton CM, Bowow RO. Valvular heart disease. In: Mann DL, Zipes DP, Libby P, Bonow ... Editorial team. Related MedlinePlus Health Topics Heart Surgery Heart Valve Diseases Browse the Encyclopedia A.D.A.M., Inc. ...

  11. Vent Relief Valve Test

    Science.gov (United States)

    2008-01-01

    Shown is the disassembly, examination, refurbishment and testing of the LH2 ( liquid hydrogen) and LOX (liquid oxygen) vent and relief valves for the S-IVB-211 engine stage in support of the Constellation/Ares project. This image is extracted from high definition video and is the highest resolution available.

  12. Measurement of reed valve kinematics

    Directory of Open Access Journals (Sweden)

    Fenkl Michael

    2016-01-01

    Full Text Available The measurement of key kinematic parameters of a reed valve movement is necessary for the further development of the reed valve system. These parameters are dependent on the geometry and material properties of the valve. As they directly affect the quantity of air flowing around the valve, a simple and easy to implement measurement of various valve configuration based on the air flow has been devised and is described in this paper, along with its technical parameters and drawbacks when evaluating reed valves used in reciprocating air compressors. Results are presented for a specimen of a compressor under examination. All kinematic parameters, and timing of the opening and closing of the valve, obtained from the measurement are presented and discussed.

  13. Measurement of reed valve kinematics

    Science.gov (United States)

    Fenkl, Michael; Dvořák, Václav; Vít, Tomáš

    2016-03-01

    The measurement of key kinematic parameters of a reed valve movement is necessary for the further development of the reed valve system. These parameters are dependent on the geometry and material properties of the valve. As they directly affect the quantity of air flowing around the valve, a simple and easy to implement measurement of various valve configuration based on the air flow has been devised and is described in this paper, along with its technical parameters and drawbacks when evaluating reed valves used in reciprocating air compressors. Results are presented for a specimen of a compressor under examination. All kinematic parameters, and timing of the opening and closing of the valve, obtained from the measurement are presented and discussed.

  14. Developments in mechanical heart valve prosthesis

    Indian Academy of Sciences (India)

    Kalyani Nair; C V Muraleedharan; G S Bhuvaneshwar

    2003-06-01

    Artificial heart valves are engineered devices used for replacing diseased or damaged natural valves of the heart. Most commonly used for replacement are mechanical heart valves and biological valves. This paper briefly outlines the evolution, designs employed, materials being used,. and important factors that affect the performance of mechanical heart valves. The clinical performance of mechanical heart valves is also addressed. Efforts made in India in the development of mechanical heart valves are also discussed.

  15. Clinical Application and Development of Medical Imaging in Transcatheter Aortic Valve Implantation%基于经皮主动脉瓣膜植入术的影像学临床应用与进展

    Institute of Scientific and Technical Information of China (English)

    崔辰; 赵世华(综述)

    2016-01-01

    经皮主动脉瓣膜植入术可作为重度主动脉狭窄外科手术治疗高危患者的备选治疗方案。心血管影像在经皮主动脉瓣膜植入术的成功实施中起着重要作用。超声心动图是观察患者瓣膜结构的一线影像学检查。多层螺旋CT可以清晰地显示主动脉根部结构,准确测量主动脉瓣环直径,对于植入瓣膜的选择有重要意义。心脏磁共振能提供患者心脏结构、功能及组织特征信息,可作为其他影像学检查的补充。同时,影像融合与3D打印技术近年来发展迅速,有望进一步提高经皮主动脉瓣膜植入术的成功率。%Transcatheter aortic valve implantation is emerging as an alternative for the treatment of patients with severe aortic stenosis and high perioperative risk or contraindication of surgery.Medical imaging is of great importance in the planning, procedural guidance, and follow-up of the procedure.In detail, echocardiography is considered as the first-line modality in the assessment of valvular anatomy.Com-puted tomography is able to reliably visualize aortic root and provides a more accurate measurement of the dimension of the aortic annulus for the proper selection of prosthesis size.Magnetic resonance imaging allows detailed assessment of cardiac morphology, function, and tissue characteristic, which can be a good alternative to other imaging modalities.Image fusion and 3D printing are developing rapidly and have great potential to improve the outcome of the procedure.

  16. Percutaneous tricuspid valve replacement in childhood

    Directory of Open Access Journals (Sweden)

    Mathias Emmel

    2015-01-01

    Full Text Available Percutaneous replacement of the tricuspid valve with a bovine jugular venous valve (melody valve was successfully undertaken in a 9-year-old boy. The patient had a previous history of bacterial endocarditis of the native tricuspid valve in infancy. Initially, a pericardial patch valve was created, followed by surgical replacement of the valve using a biological tissue valve at 4 years of age. Progressive stenosis and regurgitation of the biological valve, with severe venous congestion and resulting hepatic dysfunction prompted percutaneous valve replacement.

  17. Mitral valve replacement in systemic lupus erythematosus associated Libman-Sacks endocarditis.

    Science.gov (United States)

    Akhlaq, Anam; Ali, Taimur A; Fatimi, Saulat H

    2016-04-01

    Libman-Sacks endocarditis, first discovered in 1924, is a cardiac manifestation of systemic lupus erythematosus (SLE). Valvular involvement has been associated with SLE and antiphospholipid syndrome (APS). Mitral valve, especially its posterior leaflet, is most commonly involved. We report a case of a 34 year old woman with antiphospholipid antibody syndrome and SLE, who presented with mitral valve regurgitation. The patient underwent a prosthetic mitral valve replacement, with no followup complications. We suggest mechanical valve replacement employment in the management of mitral regurgitation in Libman-Sacks endocarditis, in view of the recent medical literature and our own case report.

  18. Transcatheter Replacement of Failed Bioprosthetic Valves

    DEFF Research Database (Denmark)

    Simonato, Matheus; Webb, John; Kornowski, Ran

    2016-01-01

    Background-Transcatheter valve implantation inside failed bioprosthetic surgical valves (valve-in-valve [ViV]) may offer an advantage over reoperation. Supra-annular transcatheter valve position may be advantageous in achieving better hemodynamics after ViV. Our objective was to define targets fo...

  19. Performance Characteristics of an Isothermal Freeze Valve

    Energy Technology Data Exchange (ETDEWEB)

    Hailey, A.E.

    2001-08-22

    This document discusses performance characteristics of an isothermal freeze valve. A freeze valve has been specified for draining the DWPF melter at the end of its lifetime. Two freeze valve designs have been evaluated on the Small Cylindrical Melter-2 (SCM-2). In order to size the DWPF freeze valve, the basic principles governing freeze valve behavior need to be identified and understood.

  20. "Vanishing" pulmonary valve stenosis

    Directory of Open Access Journals (Sweden)

    Nofil I Arain

    2012-01-01

    Full Text Available Objective: Both spontaneous resolution and progression of mild pulmonary valve stenosis (PS have been reported. We reviewed characteristics of the pulmonary valve (PV to determine factors that could influence resolution of mild PS. Methods: Fifteen asymptomatic pediatric patients with spontaneous resolution of isolated mild PS were retrospectively reviewed. Results: There was no correlation between the PV gradient, clinical presentation, age at diagnosis, or PV morphology. The PV annulus was small at initial presentation, which normalized at follow up. When corrected for the body surface area (z-score, the PV annulus was normal in all patients, including at initial evaluation. Conclusions: Based on our observation, neither age at diagnosis, nor PV-morphology-influenced resolution of mild PS. The variable clinical presentation makes it difficult to categorize and observe mild PS by auscultation alone. The PV annulus z-score could be a useful adjunct to determine the course and serial observation of mild PS.

  1. Transcatheter aortic valve implantation in failed bioprosthetic surgical valves

    DEFF Research Database (Denmark)

    Dvir, Danny; Webb, John G; Bleiziffer, Sabine

    2014-01-01

    IMPORTANCE: Owing to a considerable shift toward bioprosthesis implantation rather than mechanical valves, it is expected that patients will increasingly present with degenerated bioprostheses in the next few years. Transcatheter aortic valve-in-valve implantation is a less invasive approach......, stroke, and New York Heart Association functional class. RESULTS: Modes of bioprosthesis failure were stenosis (n = 181 [39.4%]), regurgitation (n = 139 [30.3%]), and combined (n = 139 [30.3%]). The stenosis group had a higher percentage of small valves (37% vs 20.9% and 26.6% in the regurgitation...

  2. Minimally Invasive Mitral Valve Replacement and Transfemoral Aortic Valve Implantation.

    Science.gov (United States)

    Rustenbach, Christian; Baumbach, Hardy; Hill, Stephan; Franke, Ulrich F W

    2015-01-01

    The case is reported of a symptomatic elderly patient with severe mitral regurgitation, severe aortic valve stenosis, and coronary heart disease. The coronary artery disease had been interventionally treated four years previously with stent implantation into the right coronary artery. Published studies have shown that a combination of mitral and aortic valve surgery is associated with a significantly increased risk of mortality and morbidity, particularly in elderly patients. In the present patient, both valvular malformations were successfully treated with a single-step interdisciplinary approach, namely an initial surgical mitral valve replacement followed by transfemoral transcatheter aortic valve replacement.

  3. Anterior Urethral Valves

    Directory of Open Access Journals (Sweden)

    Vidyadhar P. Mali

    2006-07-01

    Full Text Available We studied the clinical presentation and management of four patients with anterior urethral valves; a rare cause of urethral obstruction in male children. One patient presented antenatally with oligohydramnios, bilateral hydronephrosis and bladder thickening suggestive of an infravesical obstruction. Two other patients presented postnatally at 1 and 2 years of age, respectively, with poor stream of urine since birth. The fourth patient presented at 9 years with frequency and dysuria. Diagnosis was established on either micturating cystourethrogram (MCU (in 2 or on cystoscopy (in 2. All patients had cystoscopic ablation of the valves. One patient developed a postablation stricture that was resected with an end-to-end urethroplasty. He had an associated bilateral vesicoureteric junction (VUJ obstruction for which a bilateral ureteric reimplantation was done at the same time. On long-term follow-up, all patients demonstrated a good stream of urine. The renal function is normal. Patients are continent and free of urinary infections. Anterior urethral valves are rare obstructive lesions in male children. The degree of obstruction is variable, and so they may present with mild micturition difficulty or severe obstruction with hydroureteronephrosis and renal impairment. Hence, it is important to evaluate the anterior urethra in any male child with suspected infravesical obstruction. The diagnosis is established by MCU or cystoscopy and the treatment is always surgical, either a transurethral ablation or an open resection. The long-term prognosis is good.

  4. Posterior Urethral Valves

    Directory of Open Access Journals (Sweden)

    Steve J. Hodges

    2009-01-01

    Full Text Available The most common cause of lower urinary tract obstruction in male infants is posterior urethral valves. Although the incidence has remained stable, the neonatal mortality for this disorder has improved due to early diagnosis and intensive neonatal care, thanks in part to the widespread use of prenatal ultrasound evaluations. In fact, the most common reason for the diagnosis of posterior urethral valves presently is the evaluation of infants for prenatal hydronephrosis. Since these children are often diagnosed early, the urethral obstruction can be alleviated rapidly through catheter insertion and eventual surgery, and their metabolic derangements can be normalized without delay, avoiding preventable infant mortality. Of the children that survive, however, early diagnosis has not had much effect on their long-term prognosis, as 30% still develop renal insufficiency before adolescence. A better understanding of the exact cause of the congenital obstruction of the male posterior urethra, prevention of postnatal bladder and renal injury, and the development of safe methods to treat urethral obstruction prenatally (and thereby avoiding the bladder and renal damage due to obstructive uropathy are the goals for the care of children with posterior urethral valves[1].

  5. Supramolecular spin valves

    Science.gov (United States)

    Urdampilleta, M.; Klyatskaya, S.; Cleuziou, J.-P.; Ruben, M.; Wernsdorfer, W.

    2011-07-01

    Magnetic molecules are potential building blocks for the design of spintronic devices. Moreover, molecular materials enable the combination of bottom-up processing techniques, for example with conventional top-down nanofabrication. The development of solid-state spintronic devices based on the giant magnetoresistance, tunnel magnetoresistance and spin-valve effects has revolutionized magnetic memory applications. Recently, a significant improvement of the spin-relaxation time has been observed in organic semiconductor tunnel junctions, single non-magnetic molecules coupled to magnetic electrodes have shown giant magnetoresistance and hybrid devices exploiting the quantum tunnelling properties of single-molecule magnets have been proposed. Herein, we present an original spin-valve device in which a non-magnetic molecular quantum dot, made of a single-walled carbon nanotube contacted with non-magnetic electrodes, is laterally coupled through supramolecular interactions to TbPc2 single-molecule magnets (Pc=phthalocyanine). Their localized magnetic moments lead to a magnetic field dependence of the electrical transport through the single-walled carbon nanotube, resulting in magnetoresistance ratios up to 300% at temperatures less than 1 K. We thus demonstrate the functionality of a supramolecular spin valve without magnetic leads. Our results open up prospects of new spintronic devices with quantum properties.

  6. Image-based mass-spring model of mitral valve closure for surgical planning

    Science.gov (United States)

    Hammer, Peter E.; Perrin, Douglas P.; del Nido, Pedro J.; Howe, Robert D.

    2008-03-01

    Surgical repair of the mitral valve is preferred in most cases over valve replacement, but replacement is often performed instead due to the technical difficulty of repair. A surgical planning system based on patient-specific medical images that allows surgeons to simulate and compare potential repair strategies could greatly improve surgical outcomes. In such a surgical simulator, the mathematical model of mechanics used to close the valve must be able to compute the closed state quickly and to handle the complex boundary conditions imposed by the chords that tether the valve leaflets. We have developed a system for generating a triangulated mesh of the valve surface from volumetric image data of the opened valve. We then compute the closed position of the mesh using a mass-spring model of dynamics. The triangulated mesh is produced by fitting an isosurface to the volumetric image data, and boundary conditions, including the valve annulus and chord endpoints, are identified in the image data using a graphical user interface. In the mass-spring model, triangle sides are treated as linear springs, and sides shared by two triangles are treated as bending springs. Chords are treated as nonlinear springs, and self-collisions are detected and resolved. Equations of motion are solved using implicit numerical integration. Accuracy was assessed by comparison of model results with an image of the same valve taken in the closed state. The model exhibited rapid valve closure and was able to reproduce important features of the closed valve.

  7. "Medical Alley": the rise of the medical device industry in Minnesota.

    Science.gov (United States)

    Rhees, David J

    2009-01-01

    This paper analyzes the factors that led to the establishment in Minnesota of a thriving network of advanced medical device firms sometimes referred to as "Medical Alley." Factors examined include a favorable "business-technology infrastructure" that included the University of Minnesota, the migration of high-tech professionals from other industries, the emergence of specialized services and suppliers, the availability of capital, government encouragement, and support from trade associations. The seminal role of Medtronic, Inc., founded in 1949, is examined, particularly the invention of the first wearable cardiac pacemaker by the company's co-founder Earl Bakken in 1957 and Medtronic's licensing of the first fully implantable pacemaker developed by Wilson Greatbatch and William Chardack in 1960. Some of the major spin-off's from Medtronic will be examined, particularly CPI (now part of Boston Scientific) and St. Jude Medical. The paper will broadly characterize the evolution of "Medical Alley to the present.

  8. Perioperative management of patient with Bombay blood group undergoing mitral valve replacement.

    Science.gov (United States)

    Priye, Shio; Sathyanarayan, J; Shivaprakash, S; Reddy, Durgaprasad

    2015-12-01

    Bombay red blood cell phenotype is an extremely rare blood type for which patients can receive only autologous or Bombay phenotype red blood cells. We report a case of stenotic mitral valve with Bombay phenotype who underwent minimal invasive right lateral thoracotomy for the replacement of the mitral valve. A male patient from Bangladesh presented to the hospital with New York Heart Association III symptoms. His medical evaluation revealed severe mitral valve stenosis and mild aortic valve regurgitation. The patient received erythropoietin, intravenous iron succinate and folic acid tablets. Autologous blood transfusion was carried out. The mitral valve was replaced with a prosthetic valve successfully. After weaning off from cardiopulmonary bypass, heparinisation was corrected with protamine. Post-operatively, the patient received autologous red blood cells. The patient recovered after 1-day of inotropic support with adrenaline and milrinone, and diuretics and was discharged on the 5(th) post-operative day.

  9. Perioperative management of patient with Bombay blood group undergoing mitral valve replacement

    Directory of Open Access Journals (Sweden)

    Shio Priye

    2015-01-01

    Full Text Available Bombay red blood cell phenotype is an extremely rare blood type for which patients can receive only autologous or Bombay phenotype red blood cells. We report a case of stenotic mitral valve with Bombay phenotype who underwent minimal invasive right lateral thoracotomy for the replacement of the mitral valve. A male patient from Bangladesh presented to the hospital with New York Heart Association III symptoms. His medical evaluation revealed severe mitral valve stenosis and mild aortic valve regurgitation. The patient received erythropoietin, intravenous iron succinate and folic acid tablets. Autologous blood transfusion was carried out. The mitral valve was replaced with a prosthetic valve successfully. After weaning off from cardiopulmonary bypass, heparinisation was corrected with protamine. Post-operatively, the patient received autologous red blood cells. The patient recovered after 1-day of inotropic support with adrenaline and milrinone, and diuretics and was discharged on the 5 th post-operative day.

  10. Valve stem and packing assembly

    Energy Technology Data Exchange (ETDEWEB)

    Wordin, J.J.

    1991-09-03

    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents over tightening of the retaining nut and the resulting excessive friction between stem and stem packing. 2 figures.

  11. Valve stem and packing assembly

    Energy Technology Data Exchange (ETDEWEB)

    Wordin, John J. (Bingham County, ID)

    1991-01-01

    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.

  12. Valve stem and packing assembly

    Energy Technology Data Exchange (ETDEWEB)

    Wordin, J.J.

    1990-01-01

    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.

  13. Latest design of gate valves

    Energy Technology Data Exchange (ETDEWEB)

    Kurzhofer, U.; Stolte, J.; Weyand, M.

    1996-12-01

    Babcock Sempell, one of the most important valve manufacturers in Europe, has delivered valves for the nuclear power industry since the beginning of the peaceful application of nuclear power in the 1960s. The latest innovation by Babcock Sempell is a gate valve that meets all recent technical requirements of the nuclear power technology. At the moment in the United States, Germany, Sweden, and many other countries, motor-operated gate and globe valves are judged very critically. Besides the absolute control of the so-called {open_quotes}trip failure,{close_quotes} the integrity of all valve parts submitted to operational forces must be maintained. In case of failure of the limit and torque switches, all valve designs have been tested with respect to the quality of guidance of the gate. The guidances (i.e., guides) shall avoid a tilting of the gate during the closing procedure. The gate valve newly designed by Babcock Sempell fulfills all these characteristic criteria. In addition, the valve has cobalt-free seat hardfacing, the suitability of which has been proven by friction tests as well as full-scale blowdown tests at the GAP of Siemens in Karlstein, West Germany. Babcock Sempell was to deliver more than 30 gate valves of this type for 5 Swedish nuclear power stations by autumn 1995. In the presentation, the author will report on the testing performed, qualifications, and sizing criteria which led to the new technical design.

  14. Mitral Valve Prolapse in Pregnancy

    Directory of Open Access Journals (Sweden)

    Shi-Min Yuan

    Full Text Available Abstract Mitral valve prolapse is a benign condition. Mitral regurgitation is only complicated in patients with severe mitral valve prolapse. Women with mitral valve prolapse in the absence of other cardiovascular disorders tolerate pregnancy well and do not develop remarkable cardiac complications. Nevertheless, serious complications of mitral valve prolapse, including arrhythmia, infective endocarditis and cerebral ischemic events, can be present in pregnancy. Debates remain with regard to the use of prophylactic antibiotics and β-blockers in the pregnant women with mitral valve prolapse. The prognosis of the pregnant patients might be closely related to the pathological and (or functional changes of the mitral valve. Non-myxomatous mitral valve prolapse poses no or little obstetric risks in terms of pregnancy, labor and neonatal complications; whereas myxomatous mitral valve prolapse is a major etiology of valvular heart disease in women of childbearing age. In the pregnant patients with mitral valve prolapse progressing into major complications, surgical interventions are considered. Medicinal treatment of such patients with β-blockers should be a concern for the fetal safety.

  15. Innovative Stemless Valve Eliminates Emissions

    Science.gov (United States)

    2008-01-01

    Big Horn Valve Inc. (BHVI), of Sheridan, Wyoming, won a series of SBIR and Small Business Technology Transfer (STTR) contracts with Kennedy Space Center and Marshall Space Flight Center to explore and develop a revolutionary valve technology. BHVI developed a low-mass, high-efficiency, leak-proof cryogenic valve using composites and exotic metals, and had no stem-actuator, few moving parts, with an overall cylindrical shape. The valve has been installed at a methane coal gas field, and future applications are expected to include in-flight refueling of military aircraft, high-volume gas delivery systems, petroleum refining, and in the nuclear industry.

  16. Ahmed glaucoma valve implant: surgical technique and complications

    Directory of Open Access Journals (Sweden)

    Riva I

    2017-02-01

    Full Text Available Ivano Riva,1 Gloria Roberti,1 Francesco Oddone,1 Anastasios GP Konstas,2 Luciano Quaranta3 1IRCCS “Fondazione GB Bietti per l’Oftalmologia”, Rome, Italy; 21st University Department of Ophthalmology, Glaucoma Unit, AHEPA Hospital, Thessaloniki, Greece; 3Department of Medical and Surgical Specialties, Section of Ophthalmology, University of Brescia, Brescia, Italy Abstract: Implantation of Ahmed glaucoma valve is an effective surgical technique to reduce intraocular pressure in patients affected with glaucoma. While in the past, the use of this device was reserved to glaucoma refractory to multiple filtration surgical procedures, up-to-date mounting experience has encouraged its use also as a primary surgery for selected cases. Implantation of Ahmed glaucoma valve can be challenging for the surgeon, especially in patients who already underwent previous multiple surgeries. Several tips have to be acquired by the surgeon, and a long learning curve is always needed. Although the valve mechanism embedded in the Ahmed glaucoma valve decreases the risk of postoperative hypotony-related complications, it does not avoid the need of a careful follow-up. Complications related to this type of surgery include early and late postoperative hypotony, excessive capsule fibrosis around the plate, erosion of the tube or plate edge, and very rarely infection. The aim of this review is to describe surgical technique for Ahmed glaucoma valve implantation and to report related complications. Keywords: glaucoma, surgical technique, glaucoma drainage devices, Ahmed glaucoma valve, complications

  17. Whitey Gauge and Root Valves (VPS)

    Energy Technology Data Exchange (ETDEWEB)

    MISKA, C.

    2000-09-03

    These valves are 1/2 inch ball valves fabricated of 316 stainless steel: Packing is TFE (standard). They are used as isolation valves for pressure instrumentation in the Vacuum Pumping and Helium System.

  18. Risk factors for rejection for morphological reasons of heart valves for transplantation.

    Science.gov (United States)

    van Wijk, Marja J; van den Bogaerdt, Antoon; Bokhorst, Arlinke G

    2013-03-01

    The study aim was to identify risk factors for morphological rejection of aortic and pulmonary valves for transplantation that could be used to optimize donor selection. The files of all Dutch heart valve donors, donating in a 2.5 years period, whose hearts were processed at Heart Valve Bank Rotterdam, were reviewed for all factors that could be relevant for valve rejection and related to outcome of morphological assessment of the valves. Valves were retrieved from 813 deceased Dutch donors, 24.1% also donating organs. For 797 aortic and 767 pulmonary valves, who met retrieval criteria, morphological assessment was done. 69.5% of aortic and 37.5% of pulmonary valves were considered unsuitable for transplantation at morphological assessment. Backward stepwise multivariate logistic regression analysis, showed age, cardiac cause of death, cerebrovascular accident as cause of death or in medical history, and number of cardiovascular risk factors in a donor to be independent risk factors for morphological rejection of aortic valves. Age, sex, weight >100 kg and ruptured aortic aneurysm as cause of death were independent risk factors for morphological rejection of pulmonary valves. Being an organ donor was an independent predictor of morphological approval of aortic and pulmonary valves, while hypertension was an independent predictor for morphological approval of aortic valves. Thus, independent factors were identified that are associated with morphological rejection of aortic and pulmonary valves for transplantation, and that could be used to optimize donor selection by preventing unnecessary retrievals, limiting costs, while improving yield per donor with minimal compromise for availability.

  19. Transcatheter Aortic Valve Replacement in Bicuspid Aortic Valve Disease

    DEFF Research Database (Denmark)

    Mylotte, Darren; Lefevre, Thierry; Søndergaard, Lars

    2014-01-01

    BACKGROUND: Limited information exists describing the results of transcatheter aortic valve (TAV) replacement in patients with bicuspid aortic valve (BAV) disease (TAV-in-BAV). OBJECTIVES: This study sought to evaluate clinical outcomes of a large cohort of patients undergoing TAV-in-BAV. METHODS...

  20. Prosthetic valve endocarditis after transcatheter aortic valve implantation

    DEFF Research Database (Denmark)

    Olsen, Niels Thue; De Backer, Ole; Thyregod, Hans G H

    2015-01-01

    risk factors. METHODS AND RESULTS: Observational single-center study of 509 consecutive patients treated with a transcatheter implanted self-expandable aortic valve prosthesis (Medtronic CoreValve). We identified 18 patients diagnosed with TAVI-PVE during a median follow-up period of 1.4 years...

  1. High Reliability Cryogenic Piezoelectric Valve Actuator Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cryogenic fluid valves are subject to harsh exposure and actuators to drive these valves require robust performance and high reliability. DSM's piezoelectric...

  2. Ruptured aortic valve cusp: a complication of the Heimlich maneuver.

    Science.gov (United States)

    Chapman, J H; Menapace, F J; Howell, R R

    1983-07-01

    A case of traumatic rupture of the aortic valve as a complication of the Heimlich maneuver is presented. Conformation was made by comparative echocardiographic studies available from three months before and immediately following the incident. The patient refused surgical intervention and died one month later with severe congestive heart failure despite vigorous medical therapy.

  3. Histopathological study of congenital aortic valve malformations in 32 children

    Institute of Scientific and Technical Information of China (English)

    HUANG Ping; WANG Hongwei; LI Yanping; CHENG Peixuan; LIU Qingjun; ZHANG Zhenlu; LIU Jianying

    2007-01-01

    The histopathological characteristics of congenital aortic valve malformations in children were investigated.All the native surgically excised aortic valves from 32 pediatric patients suffering from symptomatic aortic valve dysfunction due to congenital aortic valve malformations between January 2003 and December 2005 were studied macroscopically and microscopically.The patients' medical records were reviewed and the clinical information was extracted.The diagnosis was made by the clinical presentation,preoperative echocardiography,intraoperative examination,and postoperative histopathological study,excluding rheumatic ot degenerative aortic valve diseases,infective endocarditis and primary connective tissue disorders,e.g.Marfan syndrome.Among 32 children with congenital aortic valve malformations,the age was ranged from six to 18 years,with a mean of 14.9 years,and there were 27 boys and five girls (male:female = 5.4:1).There were five cases of aortic stenosis (AS,15.62%),25 cases of aortic insufficiency (AI,78.13 %)and two cases of AS-AI (6.25%),without other valve diseases.Twenty cases still had other congenital heart diseases:ventricular septal defect (19 cases),patent ductus arteriosus (two cases),double-chambered right ventricle (one case),aneurysm of the right anterior aortic sinus of valsalva (three cases).Histopathological examination indicated that the cusps became thickening with unequal size,irregular shape (coiling and prolapse edge),enhanced hardness,and partly calcification.Microscopic investigation revealed the unsharp structure of valve tissue,fibrosis,myxomatous,reduced collagen fiber,rupture of elastic fibers,different degrees of infiltration of inflammatory cells,secondary calcareous and lipid deposit,and secondary fibrosis.Congenital aortic valve malformations in children involve males more than females,mostly associated with other congenital heart diseases.Aortic insufficiency is more common in children with congenital aortic valve

  4. Surge-damping vacuum valve

    Science.gov (United States)

    Bullock, Jack C.; Kelly, Benjamin E.

    1980-01-01

    A valve having a mechanism for damping out flow surges in a vacuum system which utilizes a slotted spring-loaded disk positioned adjacent the valve's vacuum port. Under flow surge conditions, the differential pressure forces the disk into sealing engagement with the vacuum port, thereby restricting the flow path to the slots in the disk damping out the flow surge.

  5. Mitral valve surgery - minimally invasive

    Science.gov (United States)

    ... Saunders; 2012:chap 61. Otto CM, Bonow RO. Valvular heart disease. In: Mann DL, Zipes DP, Libby P, Bonow ... Editorial team. Related MedlinePlus Health Topics Heart Surgery Heart Valve Diseases Mitral Valve Prolapse Browse the Encyclopedia A.D. ...

  6. Valve-"Health"-Monitoring System

    Science.gov (United States)

    Jensen, Scott L.; Drouant, George J.

    2009-01-01

    A system that includes sensors and data acquisition, wireless data-communication, and data-processing subsystems has been developed as a means of both real-time and historical tracking of information indicative of deterioration in the mechanical integrity and performance of a highgeared ball valve or a linearly actuated valve that operates at a temperature between cryogenic and ambient.

  7. Combination throttle and shutoff valve

    Science.gov (United States)

    Carriker, J. W.

    1972-01-01

    Combination of translating sleeve throttle valve and conventional poppet valve provides capability of shutting off flow completely by poppet and sleeve control of the rate of flow. Integration of the two concepts can be accomplished without difficulty and in a manner that requires a minimum of development.

  8. Variable gas leak rate valve

    Energy Technology Data Exchange (ETDEWEB)

    Eernisse, Errol P. (Albuquerque, NM); Peterson, Gary D. (Albuquerque, NM)

    1976-01-01

    A variable gas leak rate valve which utilizes a poled piezoelectric element to control opening and closing of the valve. The gas flow may be around a cylindrical rod with a tubular piezoelectric member encircling the rod for seating thereagainst to block passage of gas and for reopening thereof upon application of suitable electrical fields.

  9. EFFECT OF OXYGEN INHALATION ON MICROEMBOLIC SIGNALS IN PATIENTS WITH MECHANICAL AORTIC VALVE

    Directory of Open Access Journals (Sweden)

    K. Ghandehari Z. Izadimoud

    2005-06-01

    Full Text Available Microembolic signals (MES are frequently observed in transcranial ‎Doppler (TCD recordings of patients with mechanical heart valve (MHV. If gaseous bubbles are the underlying cause, number of MES produced by MHV could be reduced with oxygen ‎inhalation. From September 2003 to September ‎2004, a consecutive series of 14 patients ‎with St Jude aortic valve visited in the cardiology clinic were referred to ‎neurosonology unit, Valie Asr Hospital, Khorasan. TCD monitoring of MES was performed with an ultrasound device and a 2 MHz probe. The MES counts were recorded during 30 ‎minutes breathing room air and thereafter 30 minutes breathing through a facial mask ‎with reservoir bag (6 liter O2 per minute. The criteria of MES detection were ‎characteristic chirping sound, unidirectional signal, random appearance within cardiac ‎cycle and intensity increase ≥ 3dB above background. The MES counts in two periods ‎of monitoring were compared with paired t test and significance was declared at P ‎< 0.05. Twelve patients (8 females and 4 males were investigated. Oxygen ventilation ‎caused a significant decrease of MES counts in the patients in comparison to breathing ‎room air (P = 0.001. It seems that MES in patients with MHV are mainly gaseous bubbles ‎caused by blood agitation with MHV. The quantity of MES in patients with MHV is ‎not related to the risk of thromboembolic complications in these patients.

  10. Fluid mechanics of artificial heart valves.

    Science.gov (United States)

    Dasi, Lakshmi P; Simon, Helene A; Sucosky, Philippe; Yoganathan, Ajit P

    2009-02-01

    1. Artificial heart valves have been in use for over five decades to replace diseased heart valves. Since the first heart valve replacement performed with a caged-ball valve, more than 50 valve designs have been developed, differing principally in valve geometry, number of leaflets and material. To date, all artificial heart valves are plagued with complications associated with haemolysis, coagulation for mechanical heart valves and leaflet tearing for tissue-based valve prosthesis. For mechanical heart valves, these complications are believed to be associated with non-physiological blood flow patterns. 2. In the present review, we provide a bird's-eye view of fluid mechanics for the major artificial heart valve types and highlight how the engineering approach has shaped this rapidly diversifying area of research. 3. Mechanical heart valve designs have evolved significantly, with the most recent designs providing relatively superior haemodynamics with very low aerodynamic resistance. However, high shearing of blood cells and platelets still pose significant design challenges and patients must undergo life-long anticoagulation therapy. Bioprosthetic or tissue valves do not require anticoagulants due to their distinct similarity to the native valve geometry and haemodynamics, but many of these valves fail structurally within the first 10-15 years of implantation. 4. These shortcomings have directed present and future research in three main directions in attempts to design superior artificial valves: (i) engineering living tissue heart valves; (ii) development of advanced computational tools; and (iii) blood experiments to establish the link between flow and blood damage.

  11. INFLUENCE OF MIMIC CARDIAC RATE ON HYDRODYNAMICS OF DIFFERENT MECHANICAL PROSTHETIC CARDIAC VALVES IN VITRO

    Institute of Scientific and Technical Information of China (English)

    Yin-ping Chu; Jin-lian Cheng; Ru-kun Chen; Yu-bo Fan; Fang Pu

    2005-01-01

    Objective To assess the influence of mimic cardiac rate on hydrodynamics of different mechanical prosthetic cardiac valves.Methods US-made CarboMedics bileaflet valve, China-made Jiuling bileaflet valve and C-L tilting disc valve were tested via a pulsatile flow simulator in the aortic position. Testing conditions were set at mimic cardiac rates of 55 bpm, 75 bpm, 100bpm with a constant mimic cardiac output of 4 L/min. The mean pressure differences (△P), leakage volumes (LEV) and closing volumes (CLV) across each valve, and effective orifice areas (EOA) were analyzed.Results Within physiological range, △p, LEV, and CLV decreased as mimic cardiac rate increased, with a large extent of variance. EOA increased along with an increase in mimic cardiac rate. It was a different response in terms of cardiac rate alteration for different types of mechanical prosthetic cardiac valves.Conclusion Mimic cardiac rate change affects hydrodynamics of mechanical prosthetic cardiac valves. Within physiological range, the hydrodynamic of prosthetic bileaflet valve is better than that of tilting disc valve.

  12. Robotic mitral valve surgery.

    Science.gov (United States)

    Kypson, Alan P; Nifong, L Wiley; Chitwood, W Randolph

    2003-12-01

    A renaissance in cardiac surgery has begun. The early clinical experience with computer-enhanced telemanipulation systems outlines the limitations of this approach despite some procedural success. Technologic advancements, such as the use of nitinol U-clips (Coalescent Surgical Inc., Sunnyvale, CA) instead of sutures requiring manual knot tying, have been shown to decrease operative times significantly. It is expected that with further refinements and development of adjunct technologies, the technique of computer-enhanced endoscopic cardiac surgery will evolve and may prove to be beneficial for many patients. Robotic technology has provided benefits to cardiac surgery. With improved optics and instrumentation, incisions are smaller. The ergometric movements and simulated three-dimensional optics project hand-eye coordination for the surgeon. The placement of the wristlike articulations at the end of the instruments moves the pivoting action to the plane of the mitral annulus. This improves dexterity in tight spaces and allows for ambidextrous suture placement. Sutures can be placed more accurately because of tremor filtration and high-resolution video magnification. Furthermore, the robotic system may have potential as an educational tool. In the near future, surgical vision and training systems might be able to model most surgical procedures through immersive technology. Thus, a "flight simulator" concept emerges where surgeons may be able to practice and perform the operation without a patient. Already, effective curricula for training teams in robotic surgery exist. Nevertheless, certain constraints continue to limit the advancement to a totally endoscopic computer-enhanced mitral valve operation. The current size of the instruments, intrathoracic instrument collisions, and extrathoracic "elbow" conflicts still can limit dexterity. When smaller instruments are developed, these restraints may be resolved. Furthermore, a working port incision is still required for

  13. Valve-related complications after mechanical heart valve implantation.

    Science.gov (United States)

    Misawa, Yoshio

    2015-10-01

    The number of heart valve surgeries is increasing, and 19,164 patients underwent heart valve surgery in Japan in 2011. The early mortality rate has remained stable for more than 10 years. Many patients now survive for many years, with a reported 10-year survival rate of at least 60 %. However, unfavorable complications can occur after valve surgery. Valve-related complications include thromboembolisms, bleeding complications and prosthetic valve endocarditis, followed by structural and nonstructural prosthetic valve dysfunctions. Our review of studies published after 2000 revealed that the rate of all valve-related complications was 0.7-3.5 % per patient-year. Thromboembolisms occur at a rate of approximately 1 % per patient-year, and bleeding complications occur at almost 0.5 % per patient-year. Thromboembolic and hemorrhagic events related to anticoagulant therapy should be considered during life-long follow-up. The occurrence rate of endocarditis reaches 0.5 % per patient-year, with a poor postoperative survival. Structural dysfunctions have been largely overcome, and the nonstructural dysfunction rate is 0.4-1.2 % per patient-year. The nonstructural dysfunctions induced by paravalvular leaks and pannus ingrowth are also issues that need to be resolved.

  14. Patents and heart valve surgery - II: tissue valves.

    Science.gov (United States)

    Cheema, Faisal H; Kossar, Alexander P; Rehman, Atiq; Younas, Fahad; Polvani, Gianluca

    2013-08-01

    Valvular heart disease affects millions of Americans yearly and currently requires surgical intervention to repair or replace the defective valves. Through a close-knit collaboration between physicians, scientists and biomedical engineers, a vast degree of research and development has been aimed towards the optimization of prosthetic heart valves. Although various methods have made fantastic strides in producing durable prostheses, the therapeutic efficacy of prosthetic valves is inherently limited by a dependency upon lifelong anticoagulant regimens for recipients - a difficult challenge for many in clinical setting. Thus, biological tissue valves have been developed to circumvent vascular and immunemediated complications by incorporating biological materials to mimic native valves while still maintaining a necessary level of structural integrity. Over the past decade, a multitude of patents pertaining to the refinement of designs as well as the advancement in methodologies and technologies associated with biological tissue valves have been issued. This review seeks to chronicle and characterize such patents in an effort to track the past, present, and future progress as well as project the trajectory of tissue valves in the years to come.

  15. Balloon-expanding stent and delivery system for transcatheter aortic valve implantation:An animal study

    Institute of Scientific and Technical Information of China (English)

    Xiang Chen; Fei-Yu Wang; Guo-Jun Chu; Yu-Feng Zhu; Hong-Wen Tan; Xian-Xian Zhao; Yong-Wen Qin; Jun-Bo Ge

    2015-01-01

    Objective: To evaluate the feasibility and satefy of transcatheter aortic valve implantation in animals by using a new balloon-expanding valved stent. Methods: The balloon-expandable stent is made from cobalt-based alloy material and designed with a tubular, slotted structure. Fresh bovine pericardium was treated, sutured and fixed on the balloon-expandable stent. Ten healthy sheep (five males and five females), weighing an average of (25.16 ± 1.83) kg, were selected to undergo transcatheter implantation of the valve stents. The function of the valve stent was evaluated by angiography, echocardiography, and histology six months after the procedure. Results: Of the ten experimental sheep, two sheep died during the operation because the higher position of the artificial valve affected the opening of the coronary artery. We successfully implanted the aortic valve stent in other eight sheep;however, one sheep died of heart failure two weeks after the operation due to the lower position of the valve stent. The valve stents were implanted in the desired position in seven sheep. Ascending aortic angiographic and autoptic findings immediately after the operation confirmed the satisfactory location and function of the valved stent. Echocardiography, angiography, and histology at six post-operative months confirmed the satisfactory location and function of the valve stent. Conclusion: We successfully implanted our new valve stent as a replacement of native aortic valve via the transcatheter route with satisfactory outcome. Copyright © 2015, Chinese Medical Association Production. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

  16. Self-Rupturing Hermetic Valve

    Science.gov (United States)

    Tucker, Curtis E., Jr.; Sherrit, Stewart

    2011-01-01

    For commercial, military, and aerospace applications, low-cost, small, reliable, and lightweight gas and liquid hermetically sealed valves with post initiation on/off capability are highly desirable for pressurized systems. Applications include remote fire suppression, single-use system-pressurization systems, spacecraft propellant systems, and in situ instruments. Current pyrotechnic- activated rupture disk hermetic valves were designed for physically larger systems and are heavy and integrate poorly with portable equipment, aircraft, and small spacecraft and instrument systems. Additionally, current pyrotechnically activated systems impart high g-force shock loads to surrounding components and structures, which increase the risk of damage and can require additional mitigation. The disclosed mechanism addresses the need for producing a hermetically sealed micro-isolation valve for low and high pressure for commercial, aerospace, and spacecraft applications. High-precision electrical discharge machining (EDM) parts allow for the machining of mated parts with gaps less than a thousandth of an inch. These high-precision parts are used to support against pressure and extrusion, a thin hermetically welded diaphragm. This diaphragm ruptures from a pressure differential when the support is removed and/or when the plunger is forced against the diaphragm. With the addition of conventional seals to the plunger and a two-way actuator, a derivative of this design would allow nonhermetic use as an on/off or metering valve after the initial rupturing of the hermetic sealing disk. In addition, in a single-use hermetically sealed isolation valve, the valve can be activated without the use of potential leak-inducing valve body penetrations. One implementation of this technology is a high-pressure, high-flow-rate rupture valve that is self-rupturing, which is advantageous for high-pressure applications such as gas isolation valves. Once initiated, this technology is self

  17. PWR safety and relief valve test program. Valve selection/juftification report. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1982-12-01

    NUREG 0578 required that full-scale testing be performed on pressurizer safety valves and relief valves representative of those in use or planned for use in PWR plants. To obtain valve performance data for the entire population of PWR plant valves, nine safety valves and ten relief valves were selected as a fully representative set of test valves. Justification that the selected valves represent all PWR plant valves was provided by each safety and relief valve manufacturer. Both the valve selection and justification work was performed as part of the PWR Safety and Relief Valve Test Program conducted by EPRI on behalf of the PWR utilities in response to the recommendations of NUREG 0578 and the requirements of the NRC. Results of the Safety and Relief Valve Selection and Justification effort is documented in this report.

  18. 42 CFR 84.137 - Inhalation and exhalation valves; check valves; minimum requirements.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Inhalation and exhalation valves; check valves... PROTECTIVE DEVICES Supplied-Air Respirators § 84.137 Inhalation and exhalation valves; check valves; minimum requirements. (a) Inhalation and exhalation valves shall be provided where necessary and protected...

  19. 49 CFR 195.116 - Valves.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Valves. 195.116 Section 195.116 Transportation... PIPELINE Design Requirements § 195.116 Valves. Each valve installed in a pipeline system must comply with the following: (a) The valve must be of a sound engineering design. (b) Materials subject to...

  20. 14 CFR 125.133 - Fuel valves.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Fuel valves. 125.133 Section 125.133....133 Fuel valves. Each fuel valve must— (a) Comply with § 125.155; (b) Have positive stops or suitable... operation or from accelerated flight conditions are not transmitted to the lines connected to the valve....

  1. 49 CFR 192.145 - Valves.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Valves. 192.145 Section 192.145 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Design of Pipeline Components § 192.145 Valves. (a) Except for cast iron and plastic valves, each valve must meet the minimum requirements of API...

  2. 14 CFR 125.137 - Oil valves.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Oil valves. 125.137 Section 125.137....137 Oil valves. (a) Each oil valve must— (1) Comply with § 125.155; (2) Have positive stops or... the valve. (b) The closing of an oil shutoff means must not prevent feathering the propeller,...

  3. Cavitation guide for control valves

    Energy Technology Data Exchange (ETDEWEB)

    Tullis, J.P. [Tullis Engineering Consultants, Logan, UT (United States)

    1993-04-01

    This guide teaches the basic fundamentals of cavitation to provide the reader with an understanding of what causes cavitation, when it occurs, and the potential problems cavitation can cause to a valve and piping system. The document provides guidelines for understanding how to reduce the cavitation and/or select control valves for a cavitating system. The guide provides a method for predicting the cavitation intensity of control valves, and how the effect of cavitation on a system will vary with valve type, valve function, valve size, operating pressure, duration of operation and details of the piping installation. The guide defines six cavitation limits identifying cavitation intensities ranging from inception to the maximum intensity possible. The intensity of the cavitation at each limit Is described, including a brief discussion of how each level of cavitation influences the valve and system. Examples are included to demonstrate how to apply the method, including making both size and pressure scale effects corrections. Methods of controlling cavitation are discussed providing information on various techniques which can be used to design a new system or modify an existing one so it can operate at a desired level of cavitation.

  4. Is modification of the VVI backup mode in implantable cardioverter-defibrillators from St Jude medical required due to increased risk of inappropriate shocks?

    DEFF Research Database (Denmark)

    Philbert, Berit T; Tfelt-Hansen, Jacob; Jacobsen, Peter K

    2017-01-01

    a ventricular fibrillation (VF) zone starting at 146 b.p.m., with shock therapy only and changes in sensitivity settings making the ICD more sensitive. In all cases, the reason for the multiple inappropriate shocks was that the VF zone was reached due to exercise-induced sinus tachycardia or due to oversensing...

  5. Proportional valve with a piezoelectric actuator

    Science.gov (United States)

    Laski, Pawel Andrzej

    2016-11-01

    The article concerns a slotted proportional valve for use in pneumatic and hydraulic systems. There is a growing demand for both hydraulic and pneumatic ultrafast proportional valves. The conducted analysis of literature confirms the lack of such solutions for proportional valves. The currently used pneumatic systems for selection and segregation of parts and objects require ultrafast valves. The presented solution for the proportional valve can significantly improve and accelerate this type of technological processes. Furthermore, fast proportional valves can be successfully used for positional control of pneumatic and hydraulic drives. The article presents the design of a slotted divide valve and sets the maximum mass flow rate for service roads.

  6. Proportional valve with a piezoelectric actuator

    Directory of Open Access Journals (Sweden)

    Laski Pawel Andrzej

    2017-01-01

    Full Text Available The article concerns a slotted proportional valve for use in pneumatic and hydraulic systems. There is a growing demand for both hydraulic and pneumatic ultrafast proportional valves. The conducted analysis of literature confirms the lack of such solutions for proportional valves. The currently used pneumatic systems for selection and segregation of parts and objects require ultrafast valves. The presented solution for the proportional valve can significantly improve and accelerate this type of technological processes. Furthermore, fast proportional valves can be successfully used for positional control of pneumatic and hydraulic drives. The article presents the design of a slotted divide valve and sets the maximum mass flow rate for service roads.

  7. Double prosthetic aortic valve. Case report.

    Science.gov (United States)

    Liddicoat, J E; Bekassy, S M; De Bakey, M E

    1975-05-01

    A 55-year-old man underwent insection of a Hufnagel valve into his descending thoracic aorta for aortic valve insufficiency 18 years ago. He remained asymptomatic for 16 years. Because of progressive left ventricular failure his incompetent aortic valve was replaced with a De Bakey carbon ball aortic valve prosthesis 2 years later. Currently, 21 months after the operation, he is doing well with two aortic valves. Review of the literature suggests that he is the first patient reported with two aortic valves functioning concomitantly and one of the longest surviving patients with a Hufnagel valve.

  8. Transcatheter, valve-in-valve transapical aortic and mitral valve implantation, in a high risk patient with aortic and mitral prosthetic valve stenoses

    Directory of Open Access Journals (Sweden)

    Harish Ramakrishna

    2015-01-01

    Full Text Available Transcatheter valve implantation continues to grow worldwide and has been used principally for the nonsurgical management of native aortic valvular disease-as a potentially less invasive method of valve replacement in high-risk and inoperable patients with severe aortic valve stenosis. Given the burden of valvular heart disease in the general population and the increasing numbers of patients who have had previous valve operations, we are now seeing a growing number of high-risk patients presenting with prosthetic valve stenosis, who are not potential surgical candidates. For this high-risk subset transcatheter valve delivery may be the only option. Here, we present an inoperable patient with severe, prosthetic valve aortic and mitral stenosis who was successfully treated with a trans catheter based approach, with a valve-in-valve implantation procedure of both aortic and mitral valves.

  9. Thermostatic Radiator Valve Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Dentz, J. [Advanced Residential Integrated Energy Solutions Collaborative (ARIES), New York, NY (United States); Ansanelli, E. [Advanced Residential Integrated Energy Solutions Collaborative (ARIES), New York, NY (United States)

    2015-01-01

    A large stock of multifamily buildings in the Northeast and Midwest are heated by steam distribution systems. Losses from these systems are typically high and a significant number of apartments are overheated much of the time. Thermostatically controlled radiator valves (TRVs) are one potential strategy to combat this problem, but have not been widely accepted by the residential retrofit market. In this project, the ARIES team sought to better understand the current usage of TRVs by key market players in steam and hot water heating and to conduct limited experiments on the effectiveness of new and old TRVs as a means of controlling space temperatures and reducing heating fuel consumption. The project included a survey of industry professionals, a field experiment comparing old and new TRVs, and cost-benefit modeling analysis using BEopt™ (Building Energy Optimization software).

  10. Chemotherapy-related neuropathic symptoms and functional impairment in adult survivors of extracranial solid tumors of childhood: results from the St. Jude Lifetime Cohort Study.

    Science.gov (United States)

    Ness, Kirsten K; Jones, Kendra E; Smith, Webb A; Spunt, Sheri L; Wilson, Carmen L; Armstrong, Gregory T; Srivastava, Deo Kumar; Robison, Leslie L; Hudson, Melissa M; Gurney, James G

    2013-08-01

    To ascertain prevalence of peripheral sensory and motor neuropathy, and to evaluate impairments in relation to function. St. Jude Lifetime Cohort Study, a clinical follow-up study designed to evaluate adverse late effects in adult survivors of childhood cancer. A children's research hospital. Eligibility required treatment for an extracranial solid malignancy between 1962 and 2002, age ≥ 18 years, ≥ 10 years postdiagnosis, and no history of cranial radiation. Survivors (N=531) were included in the evaluation with a median age of 32 years and a median time from diagnosis of 25 years. Not applicable. Primary exposure measures were cumulative doses of vinca-alkaloid and platinum-based chemotherapies. Survivors with scores ≥ 1 on the sensory subscale of the Modified Total Neuropathy Score were classified with prevalent sensory impairment. Those with sex-specific z scores of ≤-1.3 for dorsiflexion strength were classified with prevalent motor impairment. Participants completed the 6-minute walk test (endurance), the Timed Up & Go test (mobility), and the Sensory Organization Test (balance). The prevalence of sensory and motor impairment was 20% and 17.5%, respectively. Vinca-alkaloid exposure was associated with an increased risk of motor impairment (adjusted odds ratio [OR]=1.66; 95% confidence interval [CI], 1.04-2.64) without evidence for a dose response. Platinum exposure was associated with increased risk of sensory impairment (adjusted OR=1.62; 95% CI, .97-2.72) without evidence of a dose response. Sensory impairment was associated with poor endurance (OR=1.99; 95% CI, .99-4.0) and mobility (OR=1.65; 95% CI, .96-2.83). Vincristine and cisplatin exposure may increase risk for long-term motor and sensory impairment, respectively. Survivors with sensory impairment are at increased risk for functional performance limitations. Copyright © 2013 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  11. The Influence of Schopenhauer's Voluntarism on Thomas Hardy's Jude the Obscure%叔本华唯意志论对哈代《无名的裘德》的影响

    Institute of Scientific and Technical Information of China (English)

    孙蓬蓬

    2015-01-01

    Schopenhauer's philosophy of voluntarism exert a great influence on Thomas Hardy's creation, espe⁃cially the shape of characters and the increase of tragic awareness in Jude the Obscure. Hardy's portrait of the characters and destinies about Jude, Sue and Arabella, is deeply influenced by Schopenhauer's philosophy. Scho⁃penhauer holds the nature of the world is the will, and will is people's unstoppable impulses and desires, howev⁃er, will has tragical features, so life is painful. At the late period of Hardy's novel creation, due to the impact of Schopenhauer's tragic philosophy, the tragic consciousness of character's personality and destiny further enhanc⁃es, especially the tragical portrait of Jude, Sue and the Little Father Time.%叔本华的唯意志论哲学思想,对哈代《无名的裘德》中的人物形象的塑造和悲剧意识的增强产生了重要影响。哈代对裘德、淑和艾拉白拉人物性格和命运的刻画,深受叔本华意志论哲学的影响。叔本华认为世界的本质是意志,意志是人不可遏止的生命冲动和欲望,而意志又具有悲剧性,所以人生是痛苦的。哈代小说创作后期,由于受叔本华悲剧思想的影响,人物性格和命运的悲剧意识进一步增强,特别是对裘德、淑和小时光老人悲剧形象的刻画。

  12. Human tissue valves in aortic position: determinants of reoperation and valve regurgitation

    NARCIS (Netherlands)

    T.P. Willems (Tineke); E.W. Steyerberg (Ewout); V.E. Kleyburg-Linkers; E. Bos (Egbert); L.A. van Herwerden (Lex); J.R.T.C. Roelandt (Jos); J.J.M. Takkenberg (Hanneke)

    2001-01-01

    textabstractBACKGROUND: Human tissue valves for aortic valve replacement have a limited durability that is influenced by interrelated determinants. Hierarchical linear modeling was used to analyze the relation between these determinants of durability and valve

  13. Comparison of outcomes after aortic valve replacement with a mechanical valve or a bioprosthesis using microsimulation

    NARCIS (Netherlands)

    J.P.A. Puvimanasinghe (John); M.B. Edwards; M.J.C. Eijkemans (René); E.W. Steyerberg (Ewout); L.A. van Herwerden (Lex); K.M. Taylor; G.L. Grunkemeier (Gary); J.D.F. Habbema (Dik); A.J.J.C. Bogers (Ad); J.J.M. Takkenberg (Hanneke)

    2004-01-01

    textabstractBACKGROUND: Mechanical valves and bioprostheses are widely used for aortic valve replacement. Though previous randomised studies indicate that there is no important difference in outcome after implantation with either type of valve, knowledge of outcomes after aortic va

  14. Simpler valve for reciprocating engines

    Science.gov (United States)

    Akkerman, J. W.

    1978-01-01

    Simpler design eliminating camshafts, cams, and mechanical springs should improve reliability of hydrazine powered reciprocating engines. Valve is expected to improve efficiency, and reduce weight of engines in range up to 50 horsepower.

  15. Titanium in engine valve systems

    Energy Technology Data Exchange (ETDEWEB)

    Allison, J.E.; Sherman, A.M.; Bapna, M.R.

    1987-03-01

    Titanium alloys offer a unique combination of high strength-to-weight ratio, good corrosion resistance and favorable high temperature mechanical properties. Still, their relatively high cost has discouraged consideration for widespread use in automotive components. Recent demands for increased fuel economy have led to the consideration of these alloys for use as valve train materials where higher costs might be offset by improvements in performance and fuel economy. Lighter weight valve train components permit the use of lower spring loads, thus reducing friction and increasing fuel economy. Camshaft friction measurements made on a typical small displacement engine indicate that a two-to-four percent increase in fuel economy can be achieved. Valve train components are, however, subject to a severe operating environment, including elevated temperatures, sliding wear and high mechanical loads. This paper discusses the details of alloy and heat treatment selection for optimizing valve performance.

  16. Diseases of the Tricuspid Valve

    Science.gov (United States)

    ... Kawasaki Disease Long Q-T Syndrome Marfan Syndrome Metabolic Syndrome Mitral Valve Prolapse Myocardial Bridge Myocarditis Obstructive Sleep Apnea Pericarditis Peripheral Vascular Disease Rheumatic Fever Sick Sinus Syndrome Silent Ischemia Stroke Sudden ...

  17. What Causes Heart Valve Disease?

    Science.gov (United States)

    ... a heart attack or injury to the heart. Rheumatic Fever Untreated strep throat or other infections with strep bacteria that progress to rheumatic fever can cause heart valve disease. When the body ...

  18. CONGENITAL QUADRICUSPID AORTIC-VALVE

    NARCIS (Netherlands)

    BROUWER, MHJ; DEGRAAF, JJ; EBELS, T

    1993-01-01

    Two patients with a quadricuspid aortic valve are described, one of them with concomitant juxtaposed coronary orifices facing the right hand facing sinus. The etiology and incidence of this congenital anomaly will be discussed.

  19. Minimally invasive aortic valve replacement

    DEFF Research Database (Denmark)

    Foghsgaard, Signe; Schmidt, Thomas Andersen; Kjaergard, Henrik K

    2009-01-01

    In this descriptive prospective study, we evaluate the outcomes of surgery in 98 patients who were scheduled to undergo minimally invasive aortic valve replacement. These patients were compared with a group of 50 patients who underwent scheduled aortic valve replacement through a full sternotomy....... The 30-day mortality rate for the 98 patients was zero, although 14 of the 98 mini-sternotomies had to be converted to complete sternotomies intraoperatively due to technical problems. Such conversion doubled the operative time over that of the planned full sternotomies. In the group of patients whose...... is an excellent operation in selected patients, but its true advantages over conventional aortic valve replacement (other than a smaller scar) await evaluation by means of randomized clinical trial. The "extended mini-aortic valve replacement" operation, on the other hand, is a risky procedure that should...

  20. The spin-valve transistor

    NARCIS (Netherlands)

    Monsma, Douwe Johannes

    1998-01-01

    High density magnetic recording, magnetic random access memories, displacement and current detection, contactless switching and electronic compass applications all require magnetic field sensors with unprecedented sensitivity. The spin-valve effect (giant magnetoresistance) found in 1988 in magnetic

  1. 57. Aortic valve replacement with sutureless valve and mitral valve repair in patient with infected aortic homograft

    Directory of Open Access Journals (Sweden)

    A. attia

    2016-07-01

    Full Text Available The approach of implanting aortic sutureless valve inside the calcific homograft is suitable in redo surgery especially if associated with mitral valve surgery. Aortic valve replacement in patients who have undergone previous aortic root replacement with an aortic homograft remains a technical challenge because of homograft degeneration and the need for a redo Bentall operation. We report a case of redo aortic valve replacement (valve in valve with a sutureless valve and mitral valve repair by miniband annuloplasty in a female patient aged 64 years old who underwent aortic valve replacement with homograft 14 years ago and presented by sever aortic valve regurge and sever mitral valve regurge because of infective endocarditis. This technique allows rapid aortic valve replacement in a heavily calcified aortic root. It also avoids aortic valve size affection after mitral valve repair by ordinary methods especially in patients with small aortic annulus. This technique is particularly suitable in redo procedures for homograft degeneration, it avoids performing a redo Bentall operation with its known problems as well as to avoid patient prosthesis mismatch.

  2. Intraoperative assessment of mitral valve area after mitral valve repair: comparison of different methods.

    Science.gov (United States)

    Maslow, Andrew; Gemignani, Anthony; Singh, Arun; Mahmood, Feroze; Poppas, Athena

    2011-04-01

    In the present study, 3 different methods to measure the mitral valve area (MVA) after mitral valve repair (MVRep) were studied. Data obtained immediately after repair were compared with postoperative data. The objective was to determine the feasibility and correlation between intraoperative and postoperative MVA data. A prospective study. A tertiary care medical center. Twenty-five elective adult surgical patients scheduled for MVRep. Echocardiographic data included MVAs obtained using the pressure half-time (PHT), 2-dimensional planimetry (2D-PLAN), and the continuity equation (CE). These data were obtained immediately after cardiopulmonary bypass and were compared with data obtained before hospital discharge (transthoracic echocardiogram 1) and 6 to 12 months after surgery (transthoracic echocardiogram 2). Intraoperative care was guided by hemodynamic goals designed to optimize cardiac function. The data show good agreement and correlation between MVA obtained with PHT and 2D-PLAN within and between each time period. MVA data obtained with the CE in the postoperative period were lower than and did not correlate or agree as well with other MVA data. The MVA recorded immediately after valve repair, using PHT, correlated and agreed with MVA data obtained in the postoperative period. These results contrast with previously published data and could highlight the impact of hemodynamic function during the assessment of MVA. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Clinical research of aortic valve replacement in small aortic annulus%小主动脉瓣环行主动脉瓣置换术的临床研究

    Institute of Scientific and Technical Information of China (English)

    王睿; 陈鑫; 徐明; 蒋英硕; 汪黎明; 刘培生

    2014-01-01

    Objective To compare the effect aortic valve replacement(AVR) combined with aortic root enlargement and simple St.Jude Regent AVR in small aortic annulus patients.Methods From June 2008 to June 2012,62 severe aortic valvular stenosis patients with small aortic annulus (annulus diameter of 15-21 mm) entered the study.Twenty-seven cases received AVR combined with aortic root enlargement (enlargement group) and 35 cases received simple St.Jude Regent AVR(non-enlargement group),17 mm St.Jude Regent in 15 cases(17 mm group) and 19 mm in 20 cases(19 mm group).Aortic root enlargement techniques included Nicks in 2,modified Nicks in 6 cases,modified Manouguian in 19 cases.Patients were followed up and received ultrasonic cardiogram (UCG) 3,12 months postoperatively and t-test was used for statistical comparison.Results In enlargement group,1 Nicks patient received reoperation due to aortic root hemorrhage,and died of mediastinal infection,1 Manouguian patient received permanent pacemaker.In non-enlargement group,low cardiac output syndrome in 1 case.Three months and 12 months postoperative UCG showed,comparing to preoperation,effective orifice area (EOAI) increased significantly,postoperative transvalular pressure gradient and flow rate decreased significantly in each group (P =0.000).Left ventricular diastolic diameter (LVDd) decreased significantly in both enlargement group and 19 mm group (P =0.000),but no significant change in 17 mm group (P > 0.05).In non-enlargement group,19 mm compared to 17 mm group,3 months and 12 months postoperative EOAI increased significantly,pressure gradient,flow rate and LVDd decreased significantly (t =2.449-12.291,P =0.000-0.029).Comparing to enlargement group,there were significant differences in EOAI,pressure gradient,flow rate and LVDd in 17 mm group(t =2.278-17.860,P =0.000-0.028),but no significant differences in 19 mm group(t =0.118-1.630,P =0.110-0.907).Conclusions For small aortic annulus AVR patient,19 mm and larger St.Jude

  4. Endobronchial valves in the management of recurrent haemoptysis.

    Science.gov (United States)

    Koegelenberg, Coenraad F N; Bruwer, Johannes W; Bolliger, Chris T

    2014-01-01

    Minimally invasive treatment modalities for life-threatening haemoptysis in patients unresponsive to medical interventions and/or in patients deemed functionally inoperable are limited. We describe the implantation of endobronchial valves in a patient with recurrent haemoptysis, which presents both a novel indication for the use of these devices and a novel intervention for haemoptysis. Our patient is a 30-year-old male who developed bilateral upper lobe aspergillomata following previous pulmonary tuberculosis. The patient had a history of multiple hospitalisations for life-threating haemoptysis despite repeated bronchial artery embolisations. He was deemed to be inoperable given the bilateral nature of his disease and very poor pulmonary reserves. We proceeded to identify the segments involved with the aid of computed tomography reconstruction and implanted 3 endobronchial valves. Our patient remained haemoptysis free for 6 months and experienced no stent-related complications. Moreover, he was subsequently employed as a manual labourer and showed significant improvements in his functional capacity. Endobronchial valves may therefore represent a viable medium-term treatment option as a blockade device in patients unresponsive to medical interventions and/or in patients deemed functionally inoperable. Prospective studies are indicated to better delineate the role of endobronchial valves in this setting. © 2013 S. Karger AG, Basel.

  5. Ross-Kabbani Operation in an Infant with Mitral Valve Dysplasia

    Directory of Open Access Journals (Sweden)

    Carlo Pace Napoleone

    2009-01-01

    Full Text Available Background. Mitral valve replacement can be very difficult to obtain in infants because the valve annulus diameter can be smaller than the available prosthesis. Case Report. We describe the case of a 2-month-old female weighing 3.5 kg affected by mitral valve dysplasia leading to severe valve stenosis. Despite full medication, the clinical conditions were critical and surgery was undertaken. The mitral valve was unsuitable for repair and the orifice of mitral anulus was 12 mm, too small for a mechanical prosthesis. Therefore, a Ross-Kabbani operation was undertaken, replacing the mitral valve with the pulmonary autograft and reconstructing the right ventricular outflow tract with an etherograft. Results. The postoperative course was uneventful and the clinical conditions are good at 4-month follow-up. Conclusion. The Ross-Kabbani operation can be an interesting alternative to mitral valve replacement in infants when valve repair is not achievable and there is little space for an intra-annular mechanical prosthesis implant.

  6. Design of the Modular Pneumatic Valve Terminal

    Directory of Open Access Journals (Sweden)

    Jakub E. TAKOSOGLU

    2015-11-01

    Full Text Available The paper presents design of the modular pneumatic valve terminal, which was made on the basis of the patent application No A1 402905 „A valve for controlling fluid power drives, specially for pneumatic actuators, and the control system for fluid power drives valves”. The authors describe a method of operation of the system with double-acting valve and 5/2 (five ways and two position valve. Functions of the valve, and an example of application of the valve terminal in the production process were presented. 3D solid models of all the components of the valve were made. The paper presents a complete 3D model of the valve in various configurations. Using CAD-embedded SOLIDWORKS Flow Simulation computational fluid dynamics CFD analysis was also carried out of compressed air flow in the ways of the valve elements

  7. TCT-670 Optimal Transcatheter Heart Valve Sizing in Aortic Valve in Valve Implantation: Insights from the Valve in Valve International Data (VIVID) Registry

    DEFF Research Database (Denmark)

    Alnasser, Sami; Cheema, Asim N; Horlick, Eric

    2016-01-01

    Background: Optimal transcatheter heart valve (THV) sizing is crucial to optimize procedural outcomes. Larger THV oversizing is shown to decrease paravalvular leakage post transcatheter aortic valve replacement but its role in Valve in Valve implantation (ViV) is not well established. Methods...... group received a larger THV (25.5± 1.4 mm vs. 23.3 ± 1.0 mm, pimplantation, the oversized group achieved a larger EOA (1.54±0.4cm2 vs. 1.37± 0.5cm2, p...V implantation was associated with favorable post-implant EOA and gradient but a higher risk of aortic insufficiency and THV re-intervention. Further exploration within various THV and surgical valve types at different degree of THV oversizing is planned....

  8. Development of an effective valve packing program

    Energy Technology Data Exchange (ETDEWEB)

    Hart, K.A.

    1996-12-01

    Current data now shows that graphite valve packing installed within the guidance of a controlled program produces not only reliable stem sealing but predictable running loads. By utilizing recent technological developments in valve performance monitoring for both MOV`s and AOV`s, valve packing performance can be enhanced while reducing maintenance costs. Once known, values are established for acceptable valve packing loads, the measurement of actual valve running loads via the current MOV/AOV diagnostic techniques can provide indication of future valve stem sealing problems, improper valve packing installation or identify the opportunity for valve packing program improvements. At times the full benefit of these advances in material and predictive technology remain under utilized due to simple past misconceptions associated with valve packing. This paper will explore the basis for these misconceptions, provide general insight into the current understanding of valve packing and demonstrate how with this new understanding and current valve diagnostic equipment the key aspects required to develop an effective, quality valve packing program fit together. The cost and operational benefits provided by this approach can be significant impact by the: elimination of periodic valve repacking, reduction of maintenance costs, benefits of leak-free valve operation, justification for reduced Post Maintenance Test Requirements, reduced radiation exposure, improved plant appearance.

  9. Fluid dynamics of heart valves during atrial fibrillation: a lumped parameter-based approach

    CERN Document Server

    Scarsoglio, Stefania; Guala, Andrea; Ridolfi, Luca

    2015-01-01

    Atrial fibrillation (AF) consequences on the heart valve dynamics are usually studied along with a valvular disfunction or disease, since in medical monitoring the two pathologies are often concomitant. Aim of the present work is to study, through a stochastic lumped-parameter approach, the basic fluid dynamics variations of heart valves, when only paroxysmal AF is present with respect to the normal sinus rhythm (NSR) in absence of any valvular pathology. Among the most common parameters interpreting the valvular function, the most useful turns out to be the regurgitant volume. During AF both atrial valves do not seem to worsen their performance, while the ventricular efficiency is remarkably reduced.

  10. Fluid dynamics of heart valves during atrial fibrillation: a lumped parameter-based approach.

    Science.gov (United States)

    Scarsoglio, S; Camporeale, C; Guala, A; Ridolfi, L

    2016-01-01

    Atrial fibrillation (AF) consequences on the heart valve dynamics are usually studied along with a valvular disfunction or disease, since in medical monitoring, the two pathologies are often concomitant. Aim of the present work is to study, through a stochastic lumped-parameter approach, the basic fluid dynamics variations of heart valves, when only paroxysmal AF is present with respect to the normal sinus rhythm in absence of any valvular pathology. Among the most common parameters interpreting the valvular function, the most useful turns out to be the regurgitant volume. During AF, both atrial valves do not seem to worsen their performance, while the ventricular efficiency is remarkably reduced.

  11. LOFT pressurizer safety: relief valve reliability

    Energy Technology Data Exchange (ETDEWEB)

    Brown, E.S.

    1978-01-18

    The LOFT pressurizer self-actuating safety-relief valves are constructed to the present state-of-the-art and should have reliability equivalent to the valves in use on PWR plants in the U.S. There have been no NRC incident reports on valve failures to lift that would challenge the Technical Specification Safety Limit. Fourteen valves have been reported as lifting a few percentage points outside the +-1% Tech. Spec. surveillance tolerance (9 valves tested over and 5 valves tested under specification). There have been no incident reports on failures to reseat. The LOFT surveillance program for assuring reliability is equivalent to nuclear industry practice.

  12. Aorta-atrial fistula, a rare complication of prosthetic valve endocarditis.

    Science.gov (United States)

    Dewilde, W; Kurvers, M; Jaarsma, W

    2008-05-01

    A 51-year-old male with a history of a mechanical Carbomedics aortic and mitral valve replacement in 2003 and several re-operations because of endocarditis of the mitral valve in 2007 presented with heart failure 68 days after operation. Echocardiography confirmed the presence of a fistulous connection between the aorta and the left atrium. Because of the multiple surgical interventions and high operative risk, an initial conservative medical treatment was initiated and the clinical course was uneventful to this date.

  13. Huge Left Atrium Accompanied by Normally Functioning Prosthetic Valve.

    Science.gov (United States)

    Sabzi, Feridoun

    2015-01-01

    Giant left atria are defined as those measuring larger than 8 cm and are typically found in patients who have rheumatic mitral valve disease with severe regurgitation. Enlargement of the left atrium may create compression of the surrounding structures such as the esophagus, pulmonary veins, respiratory tract, lung, inferior vena cava, recurrent laryngeal nerve, and thoracic vertebrae and lead to dysphagia, respiratory dysfunction, peripheral edema, hoarse voice, or back pain. However, a huge left atrium is usually associated with rheumatic mitral valve disease but is very rare in a normally functioning prosthetic mitral valve, as was the case in our patient. A 46-year-old woman with a past medical history of mitral valve replacement and chronic atrial fibrillation was admitted to our hospital with a chief complaint of cough and shortness of breath, worsened in the last month. Physical examination showed elevated jugular venous pressure, respiratory distress, cardiac cachexia, heart failure, hepatomegaly, and severe edema in the legs. Chest radiography revealed an inconceivably huge cardiac sell-out. Transthoracic echocardiography demonstrated a huge left atrium, associated with thrombosis, and normal function of the prosthetic mitral valve. Cardiac surgery with left atrial exploration for the extraction of the huge thrombosis and De Vega annuloplasty for tricuspid regurgitation were carried out. The postoperative course was eventful due to right ventricular failure and low cardiac output syndrome; and after two days, the patient expired with multiple organ failure. Thorough literature review showed that our case was the largest left atrium (20 × 22 cm) reported thus far in adults with a normal prosthetic mitral valve function.

  14. Huge Left Atrium Accompanied by Normally Function- ing Prosthetic Valve

    Directory of Open Access Journals (Sweden)

    Feridoun Sabzi

    2015-10-01

    Full Text Available Giant left atria are defined as those measuring larger than 8 cm and are typically found in patients who have rheumatic mitral valve disease with severe regurgitation. Enlargement of the left atrium may create compression of the surrounding structures such as the esophagus, pulmonary veins, respiratory tract, lung, inferior vena cava, recurrent laryngeal nerve, and thoracic vertebrae and lead to dysphagia, respiratory dysfunction, peripheral edema, hoarse voice, or back pain. However, a huge left atrium is usually associated with rheumatic mitral valve disease but is very rare in a normally functioning prosthetic mitral valve, as was the case in our patient. A 46-year-old woman with a past medical history of mitral valve replacement and chronic atrial fibrillation was admitted to our hospital with a chief complaint of cough and shortness of breath, worsened in the last month. Physical examination showed elevated jugular venous pressure, respiratory distress, cardiac cachexia, heart failure, hepatomegaly, and severe edema in the legs. Chest radiography revealed an inconceivably huge cardiac sell-out. Transthoracic echocardiography demonstrated a huge left atrium, associated with thrombosis, and normal function of the prosthetic mitral valve. Cardiac surgery with left atrial exploration for the extraction of the huge thrombosis and De Vega annuloplasty for tricuspid regurgitation were carried out. The postoperative course was eventful due to right ventricular failure and low cardiac output syndrome; and after two days, the patient expired with multiple organ failure. Thorough literature review showed that our case was the largest left atrium (20 × 22 cm reported thus far in adults with a normal prosthetic mitral valve function.

  15. Analysis of Complex Valve and Feed Systems

    Science.gov (United States)

    Ahuja, Vineet; Hosangadi, Ashvin; Shipman, Jeremy; Cavallo, Peter; Dash, Sanford

    2007-01-01

    A numerical framework for analysis of complex valve systems supports testing of propulsive systems by simulating key valve and control system components in the test loop. In particular, it is designed to enhance the analysis capability in terms of identifying system transients and quantifying the valve response to these transients. This system has analysis capability for simulating valve motion in complex systems operating in diverse flow regimes ranging from compressible gases to cryogenic liquids. A key feature is the hybrid, unstructured framework with sub-models for grid movement and phase change including cryogenic cavitations. The multi-element unstructured framework offers improved predictions of valve performance characteristics under steady conditions for structurally complex valves such as pressure regulator valve. Unsteady simulations of valve motion using this computational approach have been carried out for various valves in operation at Stennis Space Center such as the split-body valve and the 10-in. (approx.25.4-cm) LOX (liquid oxygen) valve and the 4-in. (approx.10 cm) Y-pattern valve (liquid nitrogen). Such simulations make use of variable grid topologies, thereby permitting solution accuracy and resolving important flow physics in the seat region of the moving valve. An advantage to this software includes possible reduction in testing costs incurred due to disruptions relating to unexpected flow transients or functioning of valve/flow control systems. Prediction of the flow anomalies leading to system vibrations, flow resonance, and valve stall can help in valve scheduling and significantly reduce the need for activation tests. This framework has been evaluated for its ability to predict performance metrics like flow coefficient for cavitating venturis and valve coefficient curves, and could be a valuable tool in predicting and understanding anomalous behavior of system components at rocket propulsion testing and design sites.

  16. Genetic and clinical factors associated with obesity among adult survivors of childhood cancer: A report from the St. Jude Lifetime Cohort.

    Science.gov (United States)

    Wilson, Carmen L; Liu, Wei; Yang, Jun J; Kang, Guolian; Ojha, Rohit P; Neale, Geoffrey A; Srivastava, Deo Kumar; Gurney, James G; Hudson, Melissa M; Robison, Leslie L; Ness, Kirsten K

    2015-07-01

    The objective of this study was to identify treatment and genetic factors associated with obesity among childhood cancer survivors. Participants included 1996 survivors who previously received treatment for cancer at St. Jude Children's Research Hospital and who survived ≥10 years from diagnosis (median age at diagnosis, 7.2 years; median age at follow-up, 32.4 years). Obesity was defined as a body mass index ≥30 kg/m(2) . The factors associated with adult obesity were identified by subgroup-specific (cranial radiation [CRT] exposure status) multivariable logistic regression. Single nucleotide polymorphisms (SNPs) associated with obesity were identified by subgroup-specific, exploratory, genome-wide association analyses using a 2-stage resampling approach with a type I error rate of 5 × 10(-6) . Forty-seven percent of survivors who received CRT and 29.4% of those who did not receive CRT were obese at evaluation. In multivariable analyses, abdominal/pelvic radiation exposure was associated with decreased prevalence of obesity among survivors regardless of CRT status (P obesity were increased among survivors who received CRT who had also received glucocorticoids (P = .014) or who were younger at diagnosis (P = .013). Among the survivors who had received CRT, 166 SNPs were associated with obesity. The strongest association was observed with reference SNP rs35669975 (P = 3.3 × 10(-8) ) on segment 33.3 of the long arm of chromosome 13 (13q33.3), approximately 30 kb downstream of FAM155A (family with sequence similarity 155, member A). SNPs within the glycine receptor α3 (GLRA3) gene and near the sex-determining region Y box 11 (SOX11) and cadherin 18 type 2 (CDH18) genes also were identified. These genes have been implicated in neural growth, repair, and connectivity. Obesity in childhood cancer survivors remains associated with previous exposure to CRT and glucocorticoids. Genetic variants related to neural connectivity may modify the risk of obesity among

  17. Titanium in Engine Valve Systems

    Science.gov (United States)

    Allison, J. E.; Sherman, A. M.; Bapna, M. R.

    1987-03-01

    Titanium alloys offer a unique combination of high strength-to-weight ratio, good corrosion resistance and favorable high temperature mechanical properties. Still, their relatively high cost has discouraged consideration for widespread use in automotive components. Recent demands for increased fuel economy have led to the consideration of these alloys for use as valve train materials where higher costs might be offset by improvements in performance and fuel economy. Lighter weight valve train components permit the use of lower spring loads, thus reducing friction and increasing fuel economy. Camshaft friction measurements made on a typical small displacement engine indicate that a twoto-four percent increase in fuel economy can be achieved. Valve train components are, however, subject to a severe operating environment, including elevated temperatures, sliding wear and high mechanical loads. This paper discusses the details of alloy and heat treatment selection for optimizing valve performance. When properly manufactured, titanium valves have been shown to withstand very stringent durability testing, indicating the technical feasibility of this approach to fuel economy improvement.

  18. Large Scale Magnetostrictive Valve Actuator

    Science.gov (United States)

    Richard, James A.; Holleman, Elizabeth; Eddleman, David

    2008-01-01

    Marshall Space Flight Center's Valves, Actuators and Ducts Design and Development Branch developed a large scale magnetostrictive valve actuator. The potential advantages of this technology are faster, more efficient valve actuators that consume less power and provide precise position control and deliver higher flow rates than conventional solenoid valves. Magnetostrictive materials change dimensions when a magnetic field is applied; this property is referred to as magnetostriction. Magnetostriction is caused by the alignment of the magnetic domains in the material s crystalline structure and the applied magnetic field lines. Typically, the material changes shape by elongating in the axial direction and constricting in the radial direction, resulting in no net change in volume. All hardware and testing is complete. This paper will discuss: the potential applications of the technology; overview of the as built actuator design; discuss problems that were uncovered during the development testing; review test data and evaluate weaknesses of the design; and discuss areas for improvement for future work. This actuator holds promises of a low power, high load, proportionally controlled actuator for valves requiring 440 to 1500 newtons load.

  19. 49 CFR 179.400-19 - Valves and gages.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Valves and gages. 179.400-19 Section 179.400-19...-19 Valves and gages. (a) Valves. Manually operated shut-off valves and control valves must be... liquid flow rates. All valves must be made from approved materials compatible with the lading and...

  20. The nordic aortic valve intervention (NOTION) trial comparing transcatheter versus surgical valve implantation

    DEFF Research Database (Denmark)

    Thyregod, Hans Gustav; Søndergaard, Lars; Ihlemann, Nikolaj;

    2013-01-01

    Degenerative aortic valve (AV) stenosis is the most prevalent heart valve disease in the western world. Surgical aortic valve replacement (SAVR) has until recently been the standard of treatment for patients with severe AV stenosis. Whether transcatheter aortic valve implantation (TAVI) can...

  1. Aortic valve replacement with the Nicks annulus enlargement procedure 12 years after mitral valve replacement.

    Science.gov (United States)

    Kazama, S; Kurata, A; Yamashita, Y

    1999-10-01

    An aortic valve replacement was successfully performed employing the Nicks annulus enlargement procedure in a case of aortic valve stenosis with small annulus 12 years after mitral valve replacement. Previous mitral valve replacement does not preclude feasibility of the Nicks procedure.

  2. Percutaneous heart valves; past, present and future.

    Science.gov (United States)

    Rozeik, M M; Wheatley, D J; Gourlay, T

    2014-09-01

    Percutaneous heart valves provide a promising future for patients refused surgery on the grounds of significant technical challenges or high risk for complications. Since the first human intervention more than 10 years ago, over 50 different types of valves have been developed. The CoreValve and Edwards SAPIEN valves have both experienced clinical trials and the latter has gained FDA approval for implantation in patients considered inoperable. Current complications, such as major vascular bleeding and stroke, prevent these valves from being commonly deployed in patients considered operable in conventional surgery. This review focuses on the past and present achievements of these valves and highlights the design considerations required to progress development further. It is envisaged that, with continued improvement in valve design and with increased clinical and engineering experience, percutaneous heart valve replacement may one day be a viable option for lower-risk operable patients.

  3. Statins for aortic valve stenosis

    Directory of Open Access Journals (Sweden)

    Luciana Thiago

    Full Text Available ABSTRACT BACKGROUND: Aortic valve stenosis is the most common type of valvular heart disease in the USA and Europe. Aortic valve stenosis is considered similar to atherosclerotic disease. Some studies have evaluated statins for aortic valve stenosis. OBJECTIVES: To evaluate the effectiveness and safety of statins in aortic valve stenosis. METHODS: Search methods: We searched the Cochrane Central Register of Controlled Trials (CENTRAL, MEDLINE, Embase, LILACS - IBECS, Web of Science and CINAHL Plus. These databases were searched from their inception to 24 November 2015. We also searched trials in registers for ongoing trials. We used no language restrictions. Selection criteria: Randomized controlled clinical trials (RCTs comparing statins alone or in association with other systemic drugs to reduce cholesterol levels versus placebo or usual care. Data collection and analysis: Primary outcomes were severity of aortic valve stenosis (evaluated by echocardiographic criteria: mean pressure gradient, valve area and aortic jet velocity, freedom from valve replacement and death from cardiovascular cause. Secondary outcomes were hospitalization for any reason, overall mortality, adverse events and patient quality of life. Two review authors independently selected trials for inclusion, extracted data and assessed the risk of bias. The GRADE methodology was employed to assess the quality of result findings and the GRADE profiler (GRADEPRO was used to import data from Review Manager 5.3 to create a 'Summary of findings' table. MAIN RESULTS: We included four RCTs with 2360 participants comparing statins (1185 participants with placebo (1175 participants. We found low-quality evidence for our primary outcome of severity of aortic valve stenosis, evaluated by mean pressure gradient (mean difference (MD -0.54, 95% confidence interval (CI -1.88 to 0.80; participants = 1935; studies = 2, valve area (MD -0.07, 95% CI -0.28 to 0.14; participants = 127; studies = 2

  4. Propellant isolation shutoff valve program

    Science.gov (United States)

    Merritt, F. L.

    1973-01-01

    An analysis and design effort directed to advancing the state-of-the-art of space storable isolation valves for control of flow of the propellants liquid fluorine/hydrazine and Flox/monomethylhydrazine is discussed. Emphasis is on achieving zero liquid leakage and capability of withstanding missions up to 10 years in interplanetary space. Included is a study of all-metal poppet sealing theory, an evaluation of candidate seal configurations, a valve actuator trade-off study and design description of a pneumo-thermally actuated soft metal poppet seal valve. The concepts and analysis leading to the soft seal approach are documented. A theoretical evaluation of seal leakage versus seal loading, related finishes and yield strengths of various materials is provided. Application of a confined soft aluminum seal loaded to 2 to 3 times yield strength is recommended. Use of either an electro-mechanical or pneumatic actuator appears to be feasible for the application.

  5. Novel Active Combustion Control Valve

    Science.gov (United States)

    Caspermeyer, Matt

    2014-01-01

    This project presents an innovative solution for active combustion control. Relative to the state of the art, this concept provides frequency modulation (greater than 1,000 Hz) in combination with high-amplitude modulation (in excess of 30 percent flow) and can be adapted to a large range of fuel injector sizes. Existing valves often have low flow modulation strength. To achieve higher flow modulation requires excessively large valves or too much electrical power to be practical. This active combustion control valve (ACCV) has high-frequency and -amplitude modulation, consumes low electrical power, is closely coupled with the fuel injector for modulation strength, and is practical in size and weight. By mitigating combustion instabilities at higher frequencies than have been previously achieved (approximately 1,000 Hz), this new technology enables gas turbines to run at operating points that produce lower emissions and higher performance.

  6. 2D SIMPLIFIED SERVO VALVE

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A novel pilot stage valve called simplified 2D valve, which utilizes both rotary and linear motions of a single spool, is presented.The rotary motion of the spool incorporating hydraulic resistance bridge, formed by a damper groove and a crescent overlap opening, is utilized as pilot to actuate linear motion of the spool.A criterion for stability is derived from the linear analysis of the valve.Special experiments are designed to acquire the mechanical stiffness, the pilot leakage and the step response.It is shown that the sectional size of the spiral groove affects the dynamic response and the stiffness contradictorily and is also very sensitive to the pilot leakage.Therefore, it is necessary to establish a balance between the static and dynamic characteristics in deciding the structural parameters.Nevertheless, it is possible to sustain the dynamic response at a fairly high level, while keeping the leakage of the pilot stage at an acceptable level.

  7. Transapical Mitral Valve-in-Valve Replacement in Patient With Previous Complex Sternal Reconstruction.

    Science.gov (United States)

    Hynes, Conor F; Fatemi, Omid; Sharma, Aditya C; Nagy, Christian D; Trachiotis, Gregory D

    2016-01-01

    We present a complex case of a transapical redo mitral valve-in-valve replacement. Repeat mitral valve replacement was indicated for severe symptomatic bioprosthetic stenosis. In addition to the patient's numerous comorbidities that included diabetes, hepatic cirrhosis, ischemic cardiomyopathy, and atrial flutter, he had undergone a previous open mitral valve replacement that was complicated by sternal dehiscence requiring extensive chest wall reconstruction. Transapical approach was performed through left minithoracotomy incision with balloon-expandable valve. Transapical valve-in-valve replacement of a stenotic mitral bioprosthesis is a viable solution in a patient with previous complex chest wall reconstruction and multiple comorbidities.

  8. Pregnancy-induced remodeling of heart valves.

    Science.gov (United States)

    Pierlot, Caitlin M; Moeller, Andrew D; Lee, J Michael; Wells, Sarah M

    2015-11-01

    Recent studies have demonstrated remodeling of aortic and mitral valves leaflets under the volume loading and cardiac expansion of pregnancy. Those valves' leaflets enlarge with altered collagen fiber architecture, content, and cross-linking and biphasic changes (decreases, then increases) in extensibility during gestation. This study extends our analyses to right-sided valves, with additional compositional measurements for all valves. Valve leaflets were harvested from nonpregnant heifers and pregnant cows. Leaflet structure was characterized by leaflet dimensions, and ECM composition was determined using standard biochemical assays. Histological studies assessed changes in cellular and ECM components. Leaflet mechanical properties were assessed using equibiaxial mechanical testing. Collagen thermal stability and cross-linking were assessed using denaturation and hydrothermal isometric tension tests. Pulmonary and tricuspid leaflet areas increased during pregnancy by 35 and 55%, respectively. Leaflet thickness increased by 20% only in the pulmonary valve and largely in the fibrosa (30% thickening). Collagen crimp length was reduced in both the tricuspid (61%) and pulmonary (42%) valves, with loss of crimped area in the pulmonary valve. Thermomechanics showed decreased collagen thermal stability with surprisingly maintained cross-link maturity. The pulmonary leaflet exhibited the biphasic change in extensibility seen in left side valves, whereas the tricuspid leaflet mechanics remained largely unchanged throughout pregnancy. The tricuspid valve exhibits a remodeling response during pregnancy that is significantly diminished from the other three valves. All valves of the heart remodel in pregnancy in a manner distinct from cardiac pathology, with much similarity valve to valve, but with interesting valve-specific responses in the aortic and tricuspid valves.

  9. Promising results after percutaneous mitral valve repair

    DEFF Research Database (Denmark)

    Ihlemann, Nikolaj; Franzen, Olaf; Jørgensen, Erik;

    2011-01-01

    Mitral valve regurgitation (MR) is the secondmost frequent valve disease in Europe. Untreated MR causes considerable morbidity and mortality. In the elderly, as many as half of these patients are denied surgery because of an estimated high surgical risk. Percutaneous mitral valve repair with the ...... with the MitraClip system resembles the Alfieristitch where a clip is used to connect the tip of the mitral valve leaflets....

  10. Infective endocarditis following percutaneous pulmonary valve replacement

    DEFF Research Database (Denmark)

    Cheung, Gary; Vejlstrup, Niels; Ihlemann, Nikolaj;

    2013-01-01

    Infective endocarditis (IE) following percutaneous pulmonary valve replacement (PPVR) with the Melody valve is rarely reported. Furthermore, there are challenges in this diagnosis; especially echocardiographic evidence of vegetation within the prosthesis may be difficult.......Infective endocarditis (IE) following percutaneous pulmonary valve replacement (PPVR) with the Melody valve is rarely reported. Furthermore, there are challenges in this diagnosis; especially echocardiographic evidence of vegetation within the prosthesis may be difficult....

  11. Promising results after percutaneous mitral valve repair

    DEFF Research Database (Denmark)

    Ihlemann, Nikolaj; Franzen, Olaf; Jørgensen, Erik;

    2011-01-01

    Mitral valve regurgitation (MR) is the secondmost frequent valve disease in Europe. Untreated MR causes considerable morbidity and mortality. In the elderly, as many as half of these patients are denied surgery because of an estimated high surgical risk. Percutaneous mitral valve repair...... with the MitraClip system resembles the Alfieristitch where a clip is used to connect the tip of the mitral valve leaflets....

  12. Heart valve clinic: rationale and organization.

    Science.gov (United States)

    Lancellotti, Patrizio; Rosenhek, Raphael; Pibarot, Philippe

    2014-09-01

    With an increasing prevalence of patients with valvular heart disease (VHD), a dedicated management approach delivered in a well-defined structure, namely, the heart valve clinic (HVC), is warranted. The HVC is made up of a multidisciplinary team with high expertise in the diagnosis, management, treatment, and surveillance of patients with VHD. The aim of the HVC is to provide the highest quality of care to patients with VHD to improve the level of adherence to current evidence and guidelines, quality of life, and short- and long-term outcomes. The HVC also provides help in (1) informing and educating patients to motivate them to take their prescribed medications and look out for signs indicating a worsening of their disease, (2) organizing meetings for updates in knowledge for modern management of patients with VHD, and (3) disseminating protocols of contemporary and good practice in VHD.

  13. Advantages with small control valves

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, Gunnar

    2008-09-15

    Between 1995 and 2005, the Swedish District Heating Association carried out several research projects concerning small dimensions on control valves. This lecture aims at giving a summary of these findings which, if they are carried out, have a great impact on the district heating system. The outcome is advantages on both the production side and the customer side. Some of the project's conclusions are as follows: 1. The simulations show that the consequences of temperature disturbances can be reduced when applying smaller control valves, especially at low outdoor temperatures (-5 deg C). 2. The consequences of flow disturbances (pump stop) are not depending on the outdoor temperature (heat demand), but results over the whole year in reduced maximum flow during the process of operation recovery. With adequately reduced valve size, the resulting maximum flow at restart can be approximately reduced to the half, leading in reduced need of pumping peak power. 3. Similarly, the maximum peak power taken from the net at net recovery will be reduced, however, this effect is not as strong as that for flow. 4. Generally, we have found clear indications for that the adjustment of the K{sub vs}-values of control valves in substations should follow a certain logical order of priority. An important factor is the location of substations in respect to the production plant and to the pressure control points in the network. Another important factor is the absolute K{sub vs}-value of the over sizing, i.e. the difference of the actual installed valve and the targeted valve size. 5. Smaller size of control valves means also an improvement of the everyday operation of the district heating net, especially in the case when flow and power peaks are expected to occur. Examples for that could be the morning peaks with increase heat and hot water demands, or such events when the air temperature is decreasing very fast because of weather phenomena. Smaller control valves will smear out the

  14. Fast-acting valve actuator

    Science.gov (United States)

    Cho, Nakwon

    1980-01-01

    A fast-acting valve actuator utilizes a spring driven pneumatically loaded piston to drive a valve gate. Rapid exhaust of pressurized gas from the pneumatically loaded side of the piston facilitates an extremely rapid piston stroke. A flexible selector diaphragm opens and closes an exhaust port in response to pressure differentials created by energizing and de-energizing a solenoid which controls the pneumatic input to the actuator as well as selectively providing a venting action to one side of the selector diaphragm.

  15. Surface spin-valve effect.

    Science.gov (United States)

    Yanson, I K; Naidyuk, Yu G; Fisun, V V; Konovalenko, A; Balkashin, O P; Triputen, L Yu; Korenivski, V

    2007-04-01

    We report an observation of spin-valve-like hysteresis within a few atomic layers at a ferromagnetic interface. We use phonon spectroscopy of nanometer-sized point contacts as an in situ probe to study the mechanism of the effect. Distinctive energy phonon peaks for contacts with dissimilar nonmagnetic outer electrodes allow localizing the observed spin switching to the top or bottom interfaces for nanometer thin ferromagnetic layers. The mechanism consistent with our data is energetically distinct atomically thin surface spin layers that can form current- or field-driven surface spin-valves within a single ferromagnetic film.

  16. Whitey SCHE Gauge and Root Valves

    Energy Technology Data Exchange (ETDEWEB)

    MISKA, C.R.

    2000-09-11

    These valves are 1/2 inch ball valves fabricated of 316 stainless steel. Packing is TFE (standard). They are used as isolation valves for pressure instrumentation in the SCHa System between the helium bottle supply manifolds and safety class helium pressure instrumentation, and in lower pressure SCHa supply line.

  17. Pregnancy in women with prosthetic heart valves

    NARCIS (Netherlands)

    Pieper, P. G.; Balci, A.; Van Dijk, A. P.

    2008-01-01

    Pregnancy in women with mechanical valve prostheses has a high maternal complication rate including valve thrombosis mid death. Coumarin derivatives are relatively safe for the mother with a lower incidence of valve thrombosis than unfractionated and low-molecular-weight heparin, but carry the risk

  18. Porcine Tricuspid Valve Anatomy and Human Compatibility

    DEFF Research Database (Denmark)

    Waziri, Farhad; Lyager Nielsen, Sten; Hasenkam, J. Michael

    2016-01-01

    before clinical use. The study aim was to evaluate and compare the tricuspid valve anatomy of porcine and human hearts. METHODS: The anatomy of the tricuspid valve and the surrounding structures that affect the valve during a cardiac cycle were examined in detail in 100 fresh and 19 formalin...

  19. Whitey SCHE Gauge and Root Valves

    Energy Technology Data Exchange (ETDEWEB)

    MISKA, C.R.

    2000-09-03

    These valves are 1/2 inch ball valves fabricated of 316 stainless steel. Packing is TFE (standard). They are used as isolation valves for pressure instrumentation in the SCHe System between the helium bottle supply manifolds and safety class helium pressure instrumentation, and in lower pressure SCHe supply line.

  20. Aerodynamic Characteristics of Tracheostomy Speaking Valves.

    Science.gov (United States)

    Fornataro-Clerici, Lisa; Zajac, David J.

    1993-01-01

    Pressure-flow characteristics were determined for four different one-way valves (Kisner, Montgomery, Olympic, and Passy-Muir) used for speech production in tracheotomy patients. Results indicated significant differences in resistance among the valves, with the resistance of one valve substantially greater than that of the normal upper airways.…

  1. 14 CFR 27.995 - Fuel valves.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel valves. 27.995 Section 27.995... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Fuel System Components § 27.995 Fuel valves. (a) There must be a positive, quick-acting valve to shut off fuel to each engine individually. (b) The control...

  2. 14 CFR 29.995 - Fuel valves.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel valves. 29.995 Section 29.995... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System Components § 29.995 Fuel valves. In addition to meeting the requirements of § 29.1189, each fuel valve must— (a) (b) Be supported so that no...

  3. 14 CFR 25.995 - Fuel valves.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel valves. 25.995 Section 25.995... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System Components § 25.995 Fuel valves. In addition to the requirements of § 25.1189 for shutoff means, each fuel valve must— (a) (b) Be supported...

  4. 14 CFR 29.1025 - Oil valves.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Oil valves. 29.1025 Section 29.1025... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Oil System § 29.1025 Oil valves. (a) Each oil shutoff.... (c) Each oil valve must have positive stops or suitable index provisions in the “on” and...

  5. 14 CFR 25.1025 - Oil valves.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Oil valves. 25.1025 Section 25.1025... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Oil System § 25.1025 Oil valves. (a) Each oil shutoff... feathering. (c) Each oil valve must have positive stops or suitable index provisions in the “on” and...

  6. 49 CFR 195.258 - Valves: General.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Valves: General. 195.258 Section 195.258... PIPELINE Construction § 195.258 Valves: General. (a) Each valve must be installed in a location that is accessible to authorized employees and that is protected from damage or tampering. (b) Each submerged...

  7. 14 CFR 121.239 - Oil valves.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Oil valves. 121.239 Section 121.239..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.239 Oil valves. (a) Each oil valve must— (1) Comply with § 121.257; (2) Have positive stops or suitable index provisions in the...

  8. 14 CFR 121.235 - Fuel valves.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Fuel valves. 121.235 Section 121.235..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.235 Fuel valves. Each fuel valve must— (a) Comply with § 121.257; (b) Have positive stops or suitable index provisions in the...

  9. 49 CFR 229.109 - Safety valves.

    Science.gov (United States)

    2010-10-01

    ....109 Safety valves. Every steam generator shall be equipped with at least two safety valves that have a combined capacity to prevent an accumulation of pressure of more than five pounds per square inch above the... ends of the safety valve discharge lines shall be located or protected so that discharged steam...

  10. Aerodynamic Characteristics of Tracheostomy Speaking Valves.

    Science.gov (United States)

    Fornataro-Clerici, Lisa; Zajac, David J.

    1993-01-01

    Pressure-flow characteristics were determined for four different one-way valves (Kisner, Montgomery, Olympic, and Passy-Muir) used for speech production in tracheotomy patients. Results indicated significant differences in resistance among the valves, with the resistance of one valve substantially greater than that of the normal upper airways.…

  11. Flow and plate motion in compressor valves

    NARCIS (Netherlands)

    Habing, Reinder André

    2005-01-01

    The Basic Valve Theory is based on steady ow characteristics. Therefore unsteady ow conditions in the model valve have been considered in order to assess effects of unsteadiness on the performance of the Basic Valve Theory. The instantaneous gas force was predicted rather accurately by the theory. H

  12. Staphylococcus saprophyticus causing native valve endocarditis.

    Science.gov (United States)

    Garduño, Eugenio; Márquez, Irene; Beteta, Alicia; Said, Ibrahim; Blanco, Javier; Pineda, Tomás

    2005-01-01

    Coagulase negative staphylococci are a rare cause of native valve endocarditis. Staphylococcus saprophyticus is a coagulase-negative Staphylococcus infrequently reported as a human pathogen, and most of the cases reported are urinary tract infections. We describe a case of native valve endocarditis attributed to this organism. The patient needed valve replacement due to heart failure.

  13. Miniature piezo electric vacuum inlet valve

    Science.gov (United States)

    Keville, Robert F.; Dietrich, Daniel D.

    1998-03-24

    A miniature piezo electric vacuum inlet valve having a fast pulse rate and is battery operated with variable flow capability. The low power (piezo electric valves which require preloading of the crystal drive mechanism and 120 Vac, thus the valve of the present invention is smaller by a factor of three.

  14. The presence of fructosamine in human aortic valves is associated with valve stiffness.

    Science.gov (United States)

    Kishabongo, Antoine S; Katchunga, Philippe; Cikomola, Justin C; De Somer, Filip M; De Buyzere, Marc L; Speeckaert, Marijn M; Delanghe, Joris R

    2016-09-01

    Human heart valves are prone to glycation, a fundamental process of ageing. The aim of this study was to establish the relationship between fructosamine formation and the mechanical properties of human aortic valves. 67 patients (age: 76±8 years) diagnosed with an aortic valve stenosis, who underwent an aortic valve replacement were enrolled. Fructosamine and calcium concentrations in aortic valves were determined. Using a transthoracic Doppler echocardiography, aortic valve orifice area and transvalvular pressure gradients were measured. In a subgroup of 32 patients, the aortic valve orifice area was sufficient to carry out mechanical testing on a LFPlus Universal material tester. An in vitro removal of fructosamine of the valve was initiated using ATP-dependent fructosamine 3-kinase (FN3K). A significant correlation was found between the aortic valve fructosamine concentration and the calculated aortic valve orifice area: Y (aortic valve orifice area, mm(2))=1.050-0.228X (aortic valve fructosamine concentration, µmol/g valve) (r=-0.38). A significantly higher calcium concentration was measured in the aortic valves of diabetics in comparison with those of non-diabetics. A multiple regression analysis revealed that the presence of diabetes mellitus and aortic valve fructosamine concentration were the main predictors of the extensibility of the aortic valves. In the in vitro deglycation study, a significant lower aortic valve fructosamine concentration was detected after treatment with FN3K. This resulted in an increased flexibility of the aortic valves. Although no direct causativeness is proven with the presented results, which just show an association between fructosamine, the effect of FN3K and aortic valve stiffness, the present study points for the first time towards a possible additional role of the Amadori products in the biomechanical properties of ageing aortic valves. Published by the BMJ Publishing Group Limited. For permission to use (where not

  15. Pressure relief valve/safety relief valve testing

    Energy Technology Data Exchange (ETDEWEB)

    Murray, W.A.; Hamm, E.R.; Barber, J.R.

    1994-02-01

    Pressure vessels and piping systems are protected form overpressurization by pressure relief valves. These safety features are required to be tested-inspected on some periodic basis and, in most cases witnessed by a third party inspector. As a result nonconformances found by third parties Westinghouse Hanford Company initiated a task team to develop a pressure safety program. This paper reveals their findings.

  16. Fluid–Structure Interaction Analysis of Papillary Muscle Forces Using a Comprehensive Mitral Valve Model with 3D Chordal Structure

    Energy Technology Data Exchange (ETDEWEB)

    Toma, Milan; Jensen, Morten Ø.; Einstein, Daniel R.; Yoganathan, Ajit P.; Cochran, Richard P.; Kunzelman, Karyn S.

    2015-07-17

    Numerical models of native heart valves are being used to study valve biomechanics to aid design and development of repair procedures and replacement devices. These models have evolved from simple two-dimensional approximations to complex three-dimensional, fully coupled fluid-structure interaction (FSI) systems. Such simulations are useful for predicting the mechanical and hemodynamic loading on implanted valve devices. A current challenge for improving the accuracy of these predictions is choosing and implementing modeling boundary conditions. In order to address this challenge, we are utilizing an advanced in-vitro system to validate FSI conditions for the mitral valve system. Explanted ovine mitral valves were mounted in an in vitro setup, and structural data for the mitral valve was acquired with *CT. Experimental data from the in-vitro ovine mitral valve system were used to validate the computational model. As the valve closes, the hemodynamic data, high speed lea et dynamics, and force vectors from the in-vitro system were compared to the results of the FSI simulation computational model. The total force of 2.6 N per papillary muscle is matched by the computational model. In vitro and in vivo force measurements are important in validating and adjusting material parameters in computational models. The simulations can then be used to answer questions that are otherwise not possible to investigate experimentally. This work is important to maximize the validity of computational models of not just the mitral valve, but any biomechanical aspect using computational simulation in designing medical devices.

  17. In Vitro Study of Influence of Mimic Cardiac Rate on Hydrodynamics of the Different Mechanical Cardiac Valve Prostheses

    Institute of Scientific and Technical Information of China (English)

    CHU Yin-ping; CHENG Jin-lian; CHEN Ru-kun; FAN Yu-bo; PU Fang

    2005-01-01

    Objective:To assess the influence of mimic cardiac rate on hydrodynamics of the different mechanical prosthetic cardiac valves. Methods: US-made CarboMedics bileaflet valve and China-made Jiuling bileaflet valve and C-L tilting disc valve have been tested in a pulsatile flow simulator in the aortic position. The testing condition was set at the mimic cardiac rate of 55 beats/min,75 beats/min,100beats/min and a constant mimic cardiac output of 4L/min. The mean pressure differences (△P) ,leakage volumes (LEV) and closing volumes (CLV) across each valve,and the effective orifice areas(EOA) have been analyzed. Results:Within the range of physiology,the △P,LEV and CLV were falling as the increasing of mimic cardiac rate,and the extent of variance was larger. The EOA was increasing with the increase of the mimic cardiac rate. It is a different response as the altering of the cardiac rate for the different type of the mechanical prosthetic cardiac valves.Conclusions:The change of the mimic cardiac rate can affect the hydrodynamics of the mechanical prosthetic cardiac valves. The hydrodynamics of the bileaflet valve prosthesis is better than the tilting disc valve.

  18. Aortic valve stenosis after previous coronary bypass: Transcatheter valve implantation or aortic valve replacement?

    Directory of Open Access Journals (Sweden)

    Jegaden Olivier

    2012-05-01

    Full Text Available Abstract We report a prospective comparison between transcatheter valve implantation (TAVI, n = 13 and surgical aortic valve replacement (AVR, n = 10 in patients with severe aortic valve stenosis and previous coronary bypass surgery (CABG. All patients had at least bilateral patent internal thoracic arteries bypass without indication of repeat revascularization. After a similar post-procedure outcome, despite one early death in TAVI group, the 1-year survival was 100% in surgical group and in transfemoral TAVI group, and 73% in transapical TAVI group. When previous CABG is the lone surgical risk factor, indications for a TAVI procedure have to be cautious, specially if transfemoral approach is not possible.

  19. Tratamento clínico de endocardite em prótese valvar complicada por abscesso para-protético Successful medical management of prosthetic-valve endocarditis complicated by perivalvular abscess

    Directory of Open Access Journals (Sweden)

    Maria do Carmo Pereira Nunes

    2009-09-01

    Full Text Available O presente artigo relata o caso de um paciente do sexo masculino, 44 anos, com endocardite em prótese aórtica complicada por abscesso para-protético. Evoluiu com melhora do processo infeccioso apenas com o tratamento clínico. História prévia de doença reumática, submetido a três cirurgias cardíacas para troca valvar por disfunção de prótese e endocardite prévia. Neste relato de caso, discutiremos as características principais do abscesso para-protético como complicação de endocarditeWe present a case of a 44-year-old man with prosthetic aortic endocarditis complicated by a perivalvular abscess. He evolved with improvement of the infectious process only under clinical treatment. The patient presented a prior history of rheumatic fever and had previously been undergone three valve replacements due to prosthesis dysfunction and previous endocarditis. In this case report we discuss the main features of perivalvular abscess complicating infective endocarditis

  20. Tricuspid regurgitation following left-sided valve surgery: echocardiographic evaluation and optimal timing of surgical treatment.

    Science.gov (United States)

    Izumi, Chisato

    2015-03-01

    Severe tricuspid regurgitation may often appear and progress late after left-sided valve surgery without left-sided valve dysfunction, significant left heart failure, and pulmonary hypertension. The clinical features, echocardiographic evaluation, treatment, and prognosis of this disease entity have been discussed, but data is limited compared with left-sided valve diseases. Tricuspid annular dilatation associated with atrial fibrillation and right ventricular dysfunction strongly relate to development of isolated tricuspid regurgitation late after left-sided valve surgery. Three-dimensional evaluation may be useful in evaluating tricuspid valve anatomy in more detail. Better prognosis in patients undergoing surgical treatment for severe isolated tricuspid regurgitation than those who were treated medically has been reported; however, the timing of isolated tricuspid valve surgery is often too late. Right ventricular function is a key word for determining the timing of isolated tricuspid valve surgery; however, it is difficult to evaluate by conventional echocardiography. One of the serious issues in the future will be how to accurately evaluate right ventricular function.

  1. A 3D velocimetry study of the flow through prosthetic heart valves

    Science.gov (United States)

    Ledesma, R.; Zenit, R.; Pulos, G.; Sanchez, E.; Juarez, A.

    2006-11-01

    Blood damage commonly appears in medical valve prothesis. It is a mayor concern for the designers and surgeons. It is well known that this damage and other complications result from the modified fluid dynamics through the replacement valve. To evaluate the performance of prosthetic heart valves, it is necessary to study the flow through them. To conduct this study , we have built a flow channel that emulates cardiac conditions and allows optical access such that a 3D-PIV velocimetry system could be used. The experiments are aimed to reconstruct the downstream structure of the flow through a mechanical and a bio-material tricuspid heart valve prothesis. Preliminary results show that the observed coherent structures can be related with haemolysis and trombosis, illnesses commonly found in valve prothesis recipients. The mean flow, the levels of strain rate and the turbulence intensity generated by the valves can also be directly related to blood damage. In general, bio-material made valves tend to reduce these complications.

  2. JUDE: An alternative UVIT pipeline

    CERN Document Server

    Murthy, Jayant; Safonova, M; Sutaria, F; Gudennavar, S B; Bubbly, S G

    2016-01-01

    We have written a set of routines to convert the Level 1 data from UVIT into scientifically useful photon lists and images. These routines are in the GNU Data Language (GDL) and are compatible with the IDL software package. We use these programs in our own scientific work will continue to update the programs as we gain an understanding of the UVIT instrument.

  3. Field Experience with Lock Culvert Valves

    Science.gov (United States)

    2013-12-01

    interesting accounts regarding their lock culvert valves. ST. LAWRENCE SEAWAY Eisenhower and Snell Locks. The valves on the Eisenhower and Snell Locks...Tainter Valve Design Lift, ft Eisenhower St. Lawrence Seaway 80 x 860 12 x 14 21.0 DSP 43 Snell St. Lawrence Seaway 80 x 860 12 x 14 21.0 3 DSP, 1 VF 49...vertical-frame valves were furnished to the SLSDC in January 2011, and one was installed in the south filling-valve location at Snell Lock. An option

  4. Aortic valve surgery - minimally invasive

    Science.gov (United States)

    ... Saunders; 2012:chap 61. Otto CM, Bonow RO. Valvular heart disease. In: Mann DL, Zipes DP, Libby P, Bonow ... A.M. Editorial team. Related MedlinePlus Health Topics Heart Valve Diseases Browse the Encyclopedia A.D.A.M., Inc. ...

  5. Microprocessor-Based Valved Controller

    Science.gov (United States)

    Norman, Arnold M., Jr.

    1987-01-01

    New controller simpler, more precise, and lighter than predecessors. Mass-flow controller compensates for changing supply pressure and temperature such as occurs when gas-supply tank becomes depleted. By periodically updating calculation of mass-flow rate, controller determines correct new position for valve and keeps mass-flow rate nearly constant.

  6. Rotary actuators for plastic valves

    Energy Technology Data Exchange (ETDEWEB)

    Rudin, M. [Georg Fischer Piping Systems Ltd, Schaffhausen (Switzerland)

    2004-07-01

    Flexibility and modularity plus a high level of quality are the defining characteristics of this new generation of actuators from Georg Fischer. In conjunction with the new 546 ball valve, the PA 11/PA 21 pneumatic actuators and the EA 11/EA 21 electric actuators form an optimally co-ordinated system. (orig.)

  7. Mitral Valve Repair: The Chordae Tendineae

    Directory of Open Access Journals (Sweden)

    Carlos-A Mestres

    2015-10-01

    Full Text Available Repair of the mitral valve is the treatment of choice for mitral valve regurgitation when the anatomy is favorable. It is well known that mitral valve repair enjoys better clinical and functional results than any other type of valve substitute. This fact is beyond doubt regardless of the etiology of the valve lesion and is of particular importance in degenerative diseases.This review analyzes the most important advances in the knowledge of the anatomy, pathophysiology, and chordal function of the mitral valve as well as the different alternatives in the surgical repair and clinical results of the most prevalent diseases of the mitral valve. An attempt has been made to organize the acquired information available in a practical way.

  8. Prosthetic Valve Endocarditis Caused by Bartonella henselae: A Case Report of Molecular Diagnostics Informing Nonsurgical Management

    Science.gov (United States)

    Bartley, Patricia; Angelakis, Emmanouil; Raoult, Didier; Sampath, Rangarajan; Bonomo, Robert A.

    2016-01-01

    Identifying the pathogen responsible for culture-negative valve endocarditis often depends on molecular studies performed on surgical specimens. A patient with Ehlers-Danlos syndrome who had an aortic graft, a mechanical aortic valve, and a mitral anulloplasty ring presented with culture-negative prosthetic valve endocarditis and aortic graft infection. Research-based polymerase chain reaction (PCR)/electrospray ionization mass spectrometry on peripheral blood samples identified Bartonella henselae. Quantitative PCR targeting the16S-23S ribonucleic acid intergenic region and Western immunoblotting confirmed this result. This, in turn, permitted early initiation of pathogen-directed therapy and subsequent successful medical management of B henselae prosthetic valve endocarditis and aortic graft infection. PMID:27844027

  9. Surgical management of tricuspid valve endocarditis in the current era: A review.

    Science.gov (United States)

    Yong, Matthew S; Coffey, Sean; Prendergast, Bernard D; Marasco, Silvana F; Zimmet, Adam D; McGiffin, David C; Saxena, Pankaj

    2016-01-01

    The incidence of isolated tricuspid valve infective endocarditis is increasing. Medical management is the mainstay of treatment but surgical intervention is required in a subset of patients. Surgical treatment options include valve excision and replacement or valve reconstruction. We searched PubMed and the Cochrane library to identify articles to be included in this review of surgical outcomes. References of selected articles were crosschecked for other relevant studies. Surgical management of tricuspid valve endocarditis can be achieved with satisfactory outcomes. However, the optimal indication and timing of surgery remain unclear, and the frequent association with intravenous drug use complicates management. Repair techniques are preferable though there is no clear evidence supporting one method over another.

  10. Percutaneous valved stent repair of a failed homograft: implications for the Ross procedure.

    Science.gov (United States)

    Pretorius, Victor; Jones, Alan; Taylor, Dylan; Coe, Yashu; Ross, David B

    2008-08-01

    A case of percutaneous pulmonary valve implantation following a failed homograft in the pulmonary position is reported. A 16-year-old boy developed infective endocarditis of his pulmonary homograft, which was implanted four years earlier during a Ross procedure for congenital aortic stenosis. Following successful medical therapy, the boy was symptomatic due to pulmonary stenosis and regurgitation. A 22 mm Melody valve (Medtronic, USA) was successfully implanted percutaneously. His symptoms resolved and he was discharged home one day after the procedure. Echocardiography at the six-month follow-up demonstrated a normally functioning pulmonary valve. Percutaneous pulmonary valve replacement may make the Ross procedure a more attractive option for patients with aortic stenosis, particularly in the pediatric population.

  11. Transvalvular mitral regurgitation following mitral valve replacement a diagnostic dilemma

    OpenAIRE

    U S Dinesh Kumar; Umesh Nareppa; Shyam Prasad Shetty; Murugesh Wali

    2015-01-01

    After mitral valve replacement with a prosthetic valve, the valve should be competent and there should not be any residual prosthetic valve regurgitation. Transvalvular residual prosthetic valve regurgitation are difficult to diagnose and quantify. we are reporting interesting TEE images as a diagnostic dilemma in a case of transvalvular mitral regurgitation following mitral valve replacement secondary to entrapment of sub-valvular apparatus in a Chitra mechanical heart valve.

  12. Transcatheter aortic valve prosthesis surgically replaced 4 months after implantation

    DEFF Research Database (Denmark)

    Thyregod, Hans Gustav; Lund, Jens Teglgaard; Engstrøm, Thomas;

    2010-01-01

    Transcatheter aortic valve implantation is a new and rapidly evolving treatment option for high-risk surgical patients with degenerative aortic valve stenosis. Long-term results with these new valve prostheses are lacking, and potential valve dysfunction and failure would require valve replacement....... We report the first case of surgical valve replacement in a patient with a dysfunctional transcatheter-implanted aortic valve prosthesis 4 months after implantation....

  13. Fault diagnosis of reciprocating compressor valve with the method integrating acoustic emission signal and simulated valve motion

    Science.gov (United States)

    Wang, Yuefei; Xue, Chuang; Jia, Xiaohan; Peng, Xueyuan

    2015-05-01

    This paper proposes a method of diagnosing faults in reciprocating compressor valves using the acoustic emission signal coupled with the simulated valve motion. The actual working condition of a valve can be obtained by analyzing the acoustic emission signal in the crank angle domain and the valve movement can be predicted by simulating the valve motion. The exact opening and closing locations of a normal valve, provided by the simulated valve motion, can be used as references for the valve fault diagnosis. The typical valve faults are diagnosed to validate the feasibility and accuracy of the proposed method. The experimental results indicate that this method can easily distinguish the normal valve, valve flutter and valve delayed closing conditions. The characteristic locations of the opening and closing of the suction and discharge valves can be clearly identified in the waveform of the acoustic emission signal and the simulated valve motion.

  14. Automated 3-dimensional aortic annular assessment by multidetector computed tomography in transcatheter aortic valve implantation.

    Science.gov (United States)

    Watanabe, Yusuke; Morice, Marie-Claude; Bouvier, Erik; Leong, Tora; Hayashida, Kentaro; Lefèvre, Thierry; Hovasse, Thomas; Romano, Mauro; Chevalier, Bernard; Donzeau-Gouge, Patrick; Farge, Arnaud; Cormier, Bertrand; Garot, Philippe

    2013-09-01

    This study sought to evaluate the accuracy, reproducibility, and predictive value for post-procedural aortic regurgitation (AR) of an automated multidetector computed tomography (MDCT) post-processing imaging software, 3mensio Valves (version 5.1.sp1, 3mensio Medical Imaging BV, the Netherlands), in the assessment of patients undergoing transcatheter aortic valve implantation (TAVI). Accurate pre-operative aortic annulus measurements are crucial for patients undergoing TAVI. One hundred five patients undergoing MDCT screening before TAVI were evaluated. Aortic annular measurement was compared between automated 3mensio Valves software and manual data post-processing software on a dedicated workstation; we analyzed the discrimination value of annulus measurement for post-procedural AR in 44 recipients of a self-expanding valve. The automated 3mensio Valves software showed good concordance with manual MDCT measurements as demonstrated by Bland-Altman analysis. The automated software provided equally good reproducibility as manual measurement, especially for measurement of aortic annulus area (intraobserver intraclass correlation coefficients 0.98 vs. 0.97, interobserver 0.98 vs. 0.95). In 44 patients after implantation of a self-expanding valve, the valve diameter/CT-measured geometric mean annulus diameter ratio by automated 3mensio Valves software showed moderate and better discrimination ability in predicting post-procedural AR compared with manual measurement (p = 0.12, area under the curve 0.77, 95% confidence interval: 0.63 to 0.91, area under the curve 0.68, 95% confidence interval: 0.50 to 0.86, respectively). The automated 3mensio Valves software demonstrated reliable, reproducible aortic annulus measurement and better predictive value for post-procedural AR, suggesting important clinical implications for pre-operative assessment of patients undergoing TAVI. Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights

  15. Early Clinical Outcome of Mitral Valve Replacement Using a Newly Designed Stentless Mitral Valve for Failure of Initial Mitral Valve Repair.

    Science.gov (United States)

    Nishida, Hidefumi; Kasegawa, Hitoshi; Kin, Hajime; Takanashi, Shuichiro

    2016-12-21

    Here we report the early outcome of mitral valve replacement using a newly designed stentless mitral valve for failure of initial mitral valve repair. Mitral valve plasty (MVP) for mitral regurgitation is currently a standard technique performed worldwide. However, whether mitral valve repair should be performed for patients with advanced leaflet damage or complicated pathology remains controversial. Mitral valve replacement might be feasible for patients who have undergone failed initial MVP; however, it is not an optimal treatment because of poor valve durability and the need for anticoagulative therapy. We report two cases of successful mitral valve replacement using a newly designed stentless mitral valve made of fresh autologous pericardium, which may have a potential benefit over mitral valve repair or mitral valve replacement with a mechanical or bioprosthetic valve.

  16. A Kinematic Analysis of the Variable Valve Timing Mechanism with Three Elements and Continuous Valve Lift

    Directory of Open Access Journals (Sweden)

    Stelian Mihalcea

    2010-01-01

    Full Text Available An innovating solution for throttle-free load control for spark-ignition engines is Variable Valve Timing system (VVT System, or VVA - Variable Valve Actuation System. In this paper is presented an analytic method for kinematic analysis of the valve timing mechanism with three elements, which mainly includes the camshaft, the roller rocker finger and an intermediate rocker arm. This type of mechanism ensures a continuous valve lift (VVL System between two extreme valve heights. It is also presented the numerical example for the variable valve lift mechanism’s motion.

  17. Redoing a bioprosthetic tricuspid valve replacement with pacemaker wire through the ruined bioprosthetic valve orifice

    Institute of Scientific and Technical Information of China (English)

    GUO Hong-wei; PAN Shi-wei; SONG Yun-hu; HU Sheng-shou

    2011-01-01

    Severe tricuspid regurgitation with permanent pacemaker wire passing through the orifice of bioprosthetic tricuspid valve is extremely rare. We present a case of such kind of patient and redid bioprosthetic tricuspid valve replacement. A hawk mouth forceps for bone surgery was used to cut off the mental ring of ruined bioprosthetic tricuspid valve and the ruined valve was removed. A new bioprosthetic tricuspid valve was implanted and the wire of permanent pacemaker was left outside the ring of bioprosthetic tricuspid valve. This method may be helpful for such kind of patient.

  18. [Successful mitral valve replacement in a patient with functional mitral regurgitation induced by cardiac sarcoidosis;report of a case].

    Science.gov (United States)

    Sato, Ken; Takazawa, Ippei; Aizawa, Kei; Misawa, Yoshio

    2015-03-01

    We report a case of cardiac sarcoidosis associated with mitral valve regurgitation. A 62-year-old woman with cardiac sarcoidosis was admitted for the treatment of an intractable mitral regurgitation. She had been treated for cardiac sarcoidosis with prednisolone, and she had undergone pacemaker implantation because of advanced complete A-V block 5 years before. However, her hemodynamics deteriorated, and echocardiography revealed severe functional mitral regurgitation, thinning of the ventricular septum, and left ventricular dysfunction. The patient underwent mitral valve replacement with a mechanical prosthetic valve, and her postoperative course was uneventful. She is currently well without exacerbation of heart failure at 2 years after operation. Functional mitral regurgitation is a relatively common complication in patients with cardiac sarcoidosis. Mitral valve replacement should be considered in patients with medically intractable mitral valve dysfunction due to cardiac sarcoidosis.

  19. 逆水行舟,不进则退--《无名的裘德》文学伦理学解读%An Analysis of“Jude the Obscure”from the Perspective of Ethical Literary Criticism

    Institute of Scientific and Technical Information of China (English)

    姚建美

    2014-01-01

    Thomas Hardy ’s Jude the Obscure narrates the violation of Victorian traditional ethical concept by the protagonists.It presents us the obstacles that prevent people to pursuit individual personality and true love in transitional period,owing to the influence of conflict between new moral standard and old one.The ethical contradiction between Jude’s fear of ethical taboos and the pursuit of free love results in his difficult ethical choice,which brings Sue with ethical dilemma. This paper is to analyze Jude the Obscure from the perspective of ethical literary criticism ,so as to show the instructing function of the novel.%哈代在《无名的裘德》中,描写了主人公裘德与女主角淑违背维多利亚时期传统伦理观念的故事,展示了19世纪末资本主义过渡时期,新旧道德标准冲突,人们追求个性与真爱所遭受到的阻力。裘德对伦理禁忌的畏惧与对自由爱情的追求形成伦理冲突,体现了他艰难的伦理选择,而裘德的伦理选择也把淑置于伦理困境之中。从文学伦理学角度来分析这一现象,可揭示小说的劝诫和教诲力量。

  20. Flow Characteristics of Butterfly Valve by PIV and CFD

    Science.gov (United States)

    Kim, S. W.; Kim, J. H.; Choi, Y. D.; Lee, Y. H.

    Butterfly valves are widely used as on-off and control valves for industrial process. The importance of butterfly valves as control valves has been increasing because the pressure loss is smaller than other types of valves and compactness is very desirable for installation. These features are desirable for saving energy and high efficiency of instruments.

  1. 49 CFR 179.500-11 - Loading and unloading valves.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Loading and unloading valves. 179.500-11 Section...-113 and 107A) § 179.500-11 Loading and unloading valves. (a) Loading and unloading valve or valves shall be mounted on the cover or threaded into the marked end of tank. These valves shall be of...

  2. Segmented ball valve is easy to open and close

    Science.gov (United States)

    Prono, E.; Shinault, L. H.; Speisman, C.

    1966-01-01

    Segmented ball valve and flowmeter in the same spherical housing provide a valve that will handle large fluid volume without bulkiness and weight of blade valves or conventional ball valves. The valve is easily opened or closed and the flowmeter remains stationary, so errors are eliminated.

  3. Transesophageal echocardiography evaluation of tricuspid and pulmonic valves

    Directory of Open Access Journals (Sweden)

    Aneeta Bhatia

    2016-01-01

    Full Text Available The tricuspid is the lost valve and the pulmonary being the most anterior, is not visualized well on TEE; The Pulmonary valve is a semilunar valve that separates the right ventricle from the pulmonary artery. It is situated anterior and superior to the aortic valve, almost at right angle to the aortic valve and parallel to the beam of the ultrasound.

  4. Bleb incarceration following Ahmed valve surgery

    Directory of Open Access Journals (Sweden)

    Gross FJ

    2016-10-01

    Full Text Available Fredric J Gross, Giovanni DiSandro Department of Ophthalmology, Eastern Virginia Medical School, Norfolk, VA, USA Abstract: Globe luxation is a painful and potentially vision-threatening condition in which the globe becomes trapped behind the eyelids requiring physician intervention in the emergency department or eye clinic. On presentation, the patient typically complains of an inability to close their eye, severe foreign body sensation, decreased vision, and significant eye pain. Although most visual symptoms are reversible and primarily result from exposure keratopathy, optic nerve damage, and permanent vision loss can occur from repeat or prolonged episodes of globe luxation. Risk factors include any congenital or acquired conditions that displace the globe anteriorly in the orbit and increased eyelid laxity that allows the globe to prolapse through the lid aperture. Typically, the precipitating event involves eyelid retraction during ophthalmic examination or an event that increases intraorbital pressure such as coughing or sneezing. Once the globe has luxated, the condition is typically worsened by blepharospasm and patients’ attempts to close the eye that worsen the entrapment. In the current case, the patient had a large superotemporal filtering bleb following Ahmed valve surgery for uncontrolled glaucoma. While instilling her glaucoma medication, she retracted her eyelids sufficiently to pull the upper lid over her filtering bleb where it became entrapped causing a similar presentation to globe luxation. Traditional methods of repositioning the globe were unsuccessful. Bleb needling was ultimately required to return the globe to a normal position. Keywords: luxation, globe, glaucoma

  5. Aerococcus viridans Native Valve Endocarditis

    Directory of Open Access Journals (Sweden)

    Wenwan Zhou

    2013-01-01

    Full Text Available Aerococcus viridans is an infrequent human pathogen and few cases of infective endocarditis have been reported. A case involving a 69-year-old man with colon cancer and hemicolectomy 14 years previously, without recurrence, is reported. A diagnosis of native mitral valve endocarditis was established on the basis of clinical presentation, characteristic echocardiographic findings and pathological specimen examination after urgent valve replacement. A viridans endocarditis appears to be particularly virulent, requiring a surgical approach in four of 10 cases reported and death in one of nine. Given the aggressive nature of A viridans endocarditis and the variable time to diagnosis (a few days to seven months, prompt recognition of symptoms and echocardiography, in addition to blood cultures, should be performed when symptoms persist.

  6. [MINIMALLY INVASIVE AORTIC VALVE REPLACEMENT].

    Science.gov (United States)

    Tabata, Minoru

    2016-03-01

    Minimally invasive aortic valve replacement (MIAVR) is defined as aortic valve replacement avoiding full sternotomy. Common approaches include a partial sternotomy right thoracotomy, and a parasternal approach. MIAVR has been shown to have advantages over conventional AVR such as shorter length of stay and smaller amount of blood transfusion and better cosmesis. However, it is also known to have disadvantages such as longer cardiopulmonary bypass and aortic cross-clamp times and potential complications related to peripheral cannulation. Appropriate patient selection is very important. Since the procedure is more complex than conventional AVR, more intensive teamwork in the operating room is essential. Additionally, a team approach during postoperative management is critical to maximize the benefits of MIAVR.

  7. [Redo Aortic and Mitral Valve Replacement by Manouguian's Procedure for Active Prosthetic Valve Infection].

    Science.gov (United States)

    Kunitomo, Ryuji; Okamoto, Ken; Moriyama, Shuji; Sakaguchi, Hisashi; Tazume, Hirokazu; Yoshinaga, Takashi; Kawasuji, Michio

    2016-03-01

    The damage to the intervalvular fibrous trigone (IVFT) by infective endocarditis makes combined aortic and mitral valve replacement difficult. We performed Manouguian's double valve replacement for such a case and obtained a good result. A 81-year-old male underwent emergency operation due to active prosthetic valve endocarditis. He had a history of receiving combined aortic and mitral valve replacement because of active infective endocarditis at the age of 74 and redo aortic valve replacement 3 years after that. The infectious lesion extended from the mitral annulus to the IVFT and the aortic annulus, and it caused the prosthetic valve detachment from the aortic annulus. Manouguian's double valve replacement was required for radical resection and reconstruction of the IVFT. No recurrent infection or paravalvular leakage was observed during 49months follow up period. Manouguian's procedure is useful for complete resection of the infected IVFT and makes combined aortic and mitral valve replacement safer.

  8. Design and performance characteristic analysis of servo valve-type water hydraulic poppet valve

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung Hwan [Pusan National University, Busan (Korea, Republic of)

    2009-09-15

    For water hydraulic system control, the flow or pressure control using high-speed solenoid valve controlled by PWM control method could be a good solution for prevention of internal leakage. However, since the PWM control of on-off valves cause extensive flow and pressure fluctuation, it is difficult to control the water hydraulic actuators precisely. In this study, the servo valve-type water hydraulic valve using proportional poppet as the main valve is designed and the performance characteristics of the servo valve-type water hydraulic valve are analyzed. Furthermore, it is demonstrated through experiments that a decline in control chamber pressure that follows the change of pilot flow is caused by the occurrence of cavitation around the proportional poppet, and that fundamental characteristics of the developed valve remain unaffected by the occurrence of cavitation

  9. Percutaneous implantation of CoreValve aortic prostheses in patients with a mechanical mitral valve.

    Science.gov (United States)

    Bruschi, Giuseppe; De Marco, Federico; Oreglia, Jacopo; Colombo, Paola; Fratto, Pasquale; Lullo, Francesca; Paino, Roberto; Frigerio, Maria; Martinelli, Luigi; Klugmann, Silvio

    2009-11-01

    Concerns exist in the field of transcatheter aortic valve implantation regarding the treatment of patients with mechanical mitral valve for possible interference between the percutaneous aortic valve and the mechanical mitral prosthesis. We report our experience with percutaneous aortic valve implantation in 4 patients with severe aortic stenosis, previously operated on for mitral valve replacement with a mechanical prosthesis. All patients underwent uneventful percutaneous retrograde CoreValve implantation (CoreValve Inc, Irvine, CA). No deformation of the nitinol tubing of the prostheses (ie, neither distortion nor malfunction of the mechanical valve in the mitral position) occurred in any of the patients. All patients are alive and asymptomatic at a mean follow-up of 171 days.

  10. Imaging of Cardiac Valves by Computed Tomography

    Directory of Open Access Journals (Sweden)

    Gudrun Feuchtner

    2013-01-01

    Full Text Available This paper describes “how to” examine cardiac valves with computed tomography, the normal, diseased valves, and prosthetic valves. A review of current scientific literature is provided. Firstly, technical basics, “how to” perform and optimize a multislice CT scan and “how to” interpret valves on CT images are outlined. Then, diagnostic imaging of the entire spectrum of specific valvular disease by CT, including prosthetic heart valves, is highlighted. The last part gives a guide “how to” use CT for planning of transcatheter aortic valve implantation (TAVI, an emerging effective treatment option for patients with severe aortic stenosis. A special focus is placed on clinical applications of cardiac CT in the context of valvular disease.

  11. 3D Printed Multimaterial Microfluidic Valve

    Science.gov (United States)

    Patrick, William G.; Sharma, Sunanda; Kong, David S.; Oxman, Neri

    2016-01-01

    We present a novel 3D printed multimaterial microfluidic proportional valve. The microfluidic valve is a fundamental primitive that enables the development of programmable, automated devices for controlling fluids in a precise manner. We discuss valve characterization results, as well as exploratory design variations in channel width, membrane thickness, and membrane stiffness. Compared to previous single material 3D printed valves that are stiff, these printed valves constrain fluidic deformation spatially, through combinations of stiff and flexible materials, to enable intricate geometries in an actuated, functionally graded device. Research presented marks a shift towards 3D printing multi-property programmable fluidic devices in a single step, in which integrated multimaterial valves can be used to control complex fluidic reactions for a variety of applications, including DNA assembly and analysis, continuous sampling and sensing, and soft robotics. PMID:27525809

  12. Two-Year Outcomes in Patients With Severe Aortic Valve Stenosis Randomized to Transcatheter Versus Surgical Aortic Valve Replacement

    DEFF Research Database (Denmark)

    Søndergaard, Lars; Steinbrüchel, Daniel Andreas; Ihlemann, Nikolaj

    2016-01-01

    BACKGROUND: The Nordic Aortic Valve Intervention (NOTION) trial was the first to randomize all-comers with severe native aortic valve stenosis to either transcatheter aortic valve replacement (TAVR) with the CoreValve self-expanding bioprosthesis or surgical aortic valve replacement (SAVR), inclu...... population. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01057173....

  13. STUDY ON FLUID THICKNESS BETWEEN POPPET AND VALVE GUIDE IN CONTROL VALVE OF INJECTOR

    Institute of Scientific and Technical Information of China (English)

    Zhang Jianming; Zhang Weigang; Wang Yawei

    2004-01-01

    The physical model of -20 diesel oil and force model of injector control valve of common rail system is built. The changes of the fluid thickness are investigated on the base of the results of CFD and experiments for control valve of injector. The results indicate that a fluid thickness of 0.02~0.03 mm between the poppet and valve guide is sufficient to dampen any excessive control valve poppet bouncing.

  14. An analysis of check valve performance characteristics based on valve design

    Energy Technology Data Exchange (ETDEWEB)

    McElhaney, K.L. [Oak Ridge National Lab., TN (United States). Engineering Technology Div.

    2000-04-01

    Although it had been theorized by nuclear industry valve experts that the two most significant factors in assessing check valve performance were valve type (or design) and operating conditions, until recently, no data was available to support their assumptions. In co-operation with the Nuclear Industry Check Valve Group (NIC), Oak Ridge National Laboratory (ORNL) undertook a review and analysis of check valve failures recorded in the Institute of Nuclear Power Operations' (INPO) Nuclear Plant Reliability Data System (NPRDS). This study involved the characterization of failures according to several parameters, including valve design (e.g. swing check, lift check). Since the valve design is not inherently included within the NPRDS engineering record for each component in the database, ORNL relied on input from NIC, valve manufacturers and catalogs to supply the missing information. As a result, nearly 60% of the 21000 check valves listed in the NPRDS component database and 85% of the 838 failures occurring during 1991-1992 were identified according to valve design. This data provided the basis to perform previously unavailable cross-correlations between parameters such as valve design versus failure mode, valve design versus failure discovery method, population/failure distributions by valve design, etc. Performance assessments and predictions based on more specific sets of parameters (as opposed to generic check valve failure rates obtained from standard reference sources that generally ignore the valve design) should result in a significant impact on future nuclear plant operations, including inservice testing (IST) practices, maintenance, and probabilistic risk assessments (PRAs) by providing a means to calculate more appropriate relative (and ultimately absolute) failure rates for check valves. (orig.)

  15. Improved valve and dash-pot assembly

    Science.gov (United States)

    Chang, S.C.

    1985-04-23

    A dash-pot valve comprises a cylinder submerged in the fluid of a housing and have a piston attached to a plunger projecting into the path of closing movement of a pivotal valve member. A vortex chamber in said cylinder is provided with targentially directed inlets to generate vortex flow upon retraction of said plunger and effect increasing resistance against said piston to progressively retard the closing rate of said valve member toward its seat.

  16. Valve and dash-pot assembly

    Science.gov (United States)

    Chang, Shih-Chih

    1986-01-01

    A dash-pot valve comprising a cylinder submerged in the fluid of a housing and having a piston attached to a plunger projecting into the path of closing movement of a pivotal valve member. A vortex chamber in said cylinder is provided with tangentially directed inlets to generate vortex flow upon retraction of said plunger and effect increasing resistance against said piston to progressively retard the closing rate of said valve member toward its seat.

  17. Check valve slam analysis in pumping station

    Science.gov (United States)

    Himr, D.; Habán, V.; Dokoupil, P.

    2016-03-01

    Pumping station supplies water for technological process. The check valve in the station was replaced with a new one. The regular test of black out discovered the high pressure pulsations accompanied with noticeable pipeline movement of discharge pipe. It was caused by late check valve closing, probably, when the back flow reached the highest possible velocity. This statement was supported with analysis of results of pressure measurement near the check valve and with a numerical simulation of the flow in the pipeline system.

  18. Low-Pressure-Drop Shutoff Valve

    Science.gov (United States)

    Thornborrow, John

    1994-01-01

    Flapper valve remains open under normal flow conditions but closes upon sudden increases to high rate of flow and remains closed until reset. Valve is fluid/mechanical analog of electrical fuse or circuit breaker. Low-pressure-drop shutoff valve contains flapper machined from cylindrical surface. During normal flow conditions, flapper presents small cross section to flow. (Useful in stopping loss of fluid through leaks in cooling systems.)

  19. AN ACTIVE VALVE WITH A CLAMPED MEMBRANE

    DEFF Research Database (Denmark)

    2009-01-01

    An active valve for use e.g. in fluidic microsystems is provided, wherein the active valve comprises a membrane having at least one flow gate, arranged between a first and a second substantially rigid element. Adjusting means provides an adjustment of the clamping force on membrane arranged between...... the first and second substantially rigid element. Hereby the flow rate through the active valve can be continuously and precisely controlled....

  20. Bistable (latching) solenoid actuated propellant isolation valve

    Science.gov (United States)

    Wichmann, H.; Deboi, H. H.

    1979-01-01

    The design, fabrication, assembly and test of a development configuration bistable (latching) solenoid actuated propellant isolation valve suitable for the control hydrazine and liquid fluorine to an 800 pound thrust rocket engine is described. The valve features a balanced poppet, utilizing metal bellows, a hard poppet/seat interface and a flexure support system for the internal moving components. This support system eliminates sliding surfaces, thereby rendering the valve free of self generated particles.

  1. [Mitral valve repair for mitral regurgitation induced by infective endocarditis complicated with ulcerative colitis; report of a case].

    Science.gov (United States)

    Shiraishi, Shoichiro; Koike, Masato; Aoshima, Minoru; Asai, Tohru

    2014-05-01

    Infective endocarditis is a rare complication of ulcerative colitis. We report on a 22-year-old man, who had been treated of ulcerative colitis for 5 years. He presented with dyspnea on effort. In spite of medical treatment, he developed congestive heart failure. Transthoracic echocardiography showed a large perforation on the anterior leaflet of the mitral valve, and prolapses of the posterior leaflet of the mitral valve with rupture of the chordae. The patient underwent mitral valve repair with an autologous pericardial patch on the anterior leaflet combined with butterfly resection and suture of the posterior leaflet. The postoperative course was uneventful.

  2. Outcome of pregnancy in women after pulmonary autograft valve replacement for congenital aortic valve disease

    NARCIS (Netherlands)

    Yap, Sing-Chien; Drenthen, Willem; Pieper, Petronella G.; Moons, Philip; Mulder, Barbara J. M.; Klieverik, Loes M.; Vliegen, Hubert W.; van Dijk, Arie P. J.; Meijboom, Folkert J.; Roos-Hesselink, Jolien W.

    Background and aim of the study: The pulmonary autograft has been recommended as the valve of choice for aortic valve replacement (AVR) in young women contemplating pregnancy. However, current information on maternal and perinatal outcome of pregnancy in women with pulmonary autograft valve

  3. Outcome of pregnancy in women after pulmonary autograft valve replacement for congenital aortic valve disease.

    NARCIS (Netherlands)

    Yap, S.C.; Drenthen, W.; Pieper, P.G.; Moons, P.; Mulder, B.J.M.; Klieverik, L.M.; Vliegen, H.W.; Dijk, A.P.J. van; Meijboom, F.J.; Roos-Hesselink, J.W.

    2007-01-01

    BACKGROUND AND AIM OF THE STUDY: The pulmonary autograft has been recommended as the valve of choice for aortic valve replacement (AVR) in young women contemplating pregnancy. However, current information on maternal and perinatal outcome of pregnancy in women with pulmonary autograft valve

  4. Outcome of pregnancy in women after pulmonary autograft valve replacement for congenital aortic valve disease

    NARCIS (Netherlands)

    Yap, Sing-Chien; Drenthen, Willem; Pieper, Petronella G.; Moons, Philip; Mulder, Barbara J. M.; Klieverik, Loes M.; Vliegen, Hubert W.; van Dijk, Arie P. J.; Meijboom, Folkert J.; Roos-Hesselink, Jolien W.

    2007-01-01

    Background and aim of the study: The pulmonary autograft has been recommended as the valve of choice for aortic valve replacement (AVR) in young women contemplating pregnancy. However, current information on maternal and perinatal outcome of pregnancy in women with pulmonary autograft valve replacem

  5. Outcome of pregnancy in women after pulmonary autograft valve replacement for congenital aortic valve disease.

    NARCIS (Netherlands)

    Yap, S.C.; Drenthen, W.; Pieper, P.G.; Moons, P.; Mulder, B.J.M.; Klieverik, L.M.; Vliegen, H.W.; Dijk, A.P.J. van; Meijboom, F.J.; Roos-Hesselink, J.W.

    2007-01-01

    BACKGROUND AND AIM OF THE STUDY: The pulmonary autograft has been recommended as the valve of choice for aortic valve replacement (AVR) in young women contemplating pregnancy. However, current information on maternal and perinatal outcome of pregnancy in women with pulmonary autograft valve replacem

  6. Transapical JenaValve in a patient with mechanical mitral valve prosthesis.

    LENUS (Irish Health Repository)

    O' Sullivan, Katie E

    2014-01-29

    We report the first case of transcatheter aortic valve replacement implantation using JenaValve™ in a patient with mechanical mitral valve prosthesis. We believe that the design features of this valve may be particularly suited for use in this setting. © 2014 Wiley Periodicals, Inc.

  7. Matching flow characteristics of standard shutoff valves eliminates need for custom fabricated valves

    Science.gov (United States)

    Bevan, A. F.

    1966-01-01

    Standard high pressure valves are used in low pressure fluid system testing when a substantial system pressure increase is required. The flow-vs-valve stroke is matched with that of the valves being replaced. Some correction to the plug contour may be necessary.

  8. New-onset atrial fibrillation after surgical aortic valve replacement and transcatheter aortic valve implantation

    DEFF Research Database (Denmark)

    Jørgensen, Troels Højsgaard; Thygesen, Julie Bjerre; Thyregod, Hans Gustav;

    2015-01-01

    Surgical aortic valve replacement (SAVR) and, more recently, transcatheter aortic valve implantation (TAVI) have been shown to be the only treatments that can improve the natural cause of severe aortic valve stenosis. However, after SAVR and TAVI, the incidence of new-onset atrial fibrillation...

  9. New-Onset Atrial Fibrillation After Surgical Aortic Valve Replacement and Transcatheter Aortic Valve Implantation

    DEFF Research Database (Denmark)

    Jørgensen, Troels Højsgaard; Thygesen, Julie Bjerre; Thyregod, Hans Gustav;

    2015-01-01

    Surgical aortic valve replacement (SAVR) and, more recently, transcatheter aortic valve implantation (TAVI) have been shown to be the only treatments that can improve the natural cause of severe aortic valve stenosis. However, after SAVR and TAVI, the incidence of new-onset atrial fibrillation...

  10. Repositioning of an Intraventricular Dislocated Aortic Valve during Transcatheter Aortic Valve Implantation

    NARCIS (Netherlands)

    Natour, Ehsan; Douglas, Yvonne L.; Jainandunsing, Jayant S.; Schurer, Remco A. J.; van der Werf, Hendrik W.; van den Heuvel, Ad F. M.

    2014-01-01

    The case is presented of a 75-year-old man referred for transcatheter aortic valve implantation. During the procedure the prosthetic aortic valve became dislocated into the left ventricle shortly after expansion. The subsequent steps taken to reposition the valve using only materials at hand are des

  11. New-Onset Atrial Fibrillation After Surgical Aortic Valve Replacement and Transcatheter Aortic Valve Implantation

    DEFF Research Database (Denmark)

    Jørgensen, Troels Højsgaard; Thygesen, Julie Bjerre; Thyregod, Hans Gustav

    2015-01-01

    Surgical aortic valve replacement (SAVR) and, more recently, transcatheter aortic valve implantation (TAVI) have been shown to be the only treatments that can improve the natural cause of severe aortic valve stenosis. However, after SAVR and TAVI, the incidence of new-onset atrial fibrillation...

  12. Bicuspid Aortic Valve Disease and Ascending Aortic Aneurysms: Gaps in Knowledge

    Directory of Open Access Journals (Sweden)

    Katie L. Losenno

    2012-01-01

    Full Text Available The bicuspid aortic valve is the most common congenital cardiac anomaly in developed nations. The abnormal bicuspid morphology of the aortic valve results in valvular dysfunction and subsequent hemodynamic derangements. However, the clinical presentation of bicuspid aortic valve disease remains quite heterogeneous with patients presenting from infancy to late adulthood with variable degrees of valvular stenosis and insufficiency and associated abnormalities including aortic coarctation, hypoplastic left heart structures, and ascending aortic dilatation. Emerging evidence suggests that the heterogeneous presentation of bicuspid aortic valve phenotypes may be a more complex matter related to congenital, genetic, and/or connective tissue abnormalities. Optimal management of patients with BAV disease and associated ascending aortic aneurysms often requires a thoughtful approach, carefully assessing various risk factors of the aortic valve and the aorta and discerning individual indications for ongoing surveillance, medical management, and operative intervention. We review current concepts of anatomic classification, pathophysiology, natural history, and clinical management of bicuspid aortic valve disease with associated ascending aortic aneurysms.

  13. IL-10 and ET-1 as biomarkers of rheumatic valve disease

    Directory of Open Access Journals (Sweden)

    Sydney Correia Leão

    2014-03-01

    Full Text Available Objective: To evaluate the immunological profile and gene expression of endothelin-1 (ET-1 in mitral valves of patients with rheumatic fever originated from a reference service in cardiovascular surgery. Methods: This was a quantitative, observational and cross-sectional study. Thirty-five subjects (divided into four groups participated in the study, 25 patients with chronic rheumatic heart disease and ten control subjects. The mean age of the sample studied was 34.5 years. Seventeen of them (48.58% were male and 18 (51.42% were female. Inflammatory cytokines (TNF-α, IL-4 and IL-10 were measured and ten mitral valves of patients who underwent first valve replacement were collected for determination of gene expression of endothelin-1 by real time PCR. Results: Among the groups studied (patients vs. controls, there was a statistically significant difference in IL-10 levels (P=0.002, and no differences in other cytokines. Expression of endothelin-1 was observed in 70% of samples. Quantitatively, average of ET-1 expression was 62.85±25.63%. Conclusion: Inflammatory cytokine IL-10 participates in the maintenance of chronicity of rheumatic fever in patients who underwent valve replacement and those who are undergoing medical treatment. The expression of endothelin-1 in heart valve lesions in patients undergoing mitral valve replacement confirms its association with inflammatory activity in rheumatic fever.

  14. Optically addressable single-use microfluidic valves by laser printer lithography.

    Science.gov (United States)

    Garcia-Cordero, Jose L; Kurzbuch, Dirk; Benito-Lopez, Fernando; Diamond, Dermot; Lee, Luke P; Ricco, Antonio J

    2010-10-21

    We report the design, fabrication, and characterization of practical microfluidic valves fabricated using laser printer lithography. These optofluidic valves are opened by directing optical energy from a solid-state laser, with similar power characteristics to those used in CD/DVD drives, to a spot of printed toner where localized heating melts an orifice in the polymer layer in as little as 500 ms, connecting previously isolated fluidic components or compartments. Valve functionality, response time, and laser input energy dependence of orifice size are reported for cyclo-olefin polymer (COP) and polyethylene terephthalate (PET) films. Implementation of these optofluidic valves is demonstrated on pressure-driven and centrifugal microfluidic platforms. In addition, these "one-shot" valves comprise a continuous polymer film that hermetically isolates on-chip fluid volumes within fluidic devices using low-vapor-permeability materials; we confirmed this for a period of one month. The fabrication and integration of optofluidic valves are compatible with a range of polymer microfabrication technologies and should facilitate the development of fully integrated, reconfigurable, and automated lab-on-a-chip systems, particularly when reagents must be stored on chip for extended periods, e.g. for medical diagnostic devices, lab-on-a-chip synthetic systems, or hazardous biochemical analysis platforms.

  15. Hydraulic engine valve actuation system including independent feedback control

    Science.gov (United States)

    Marriott, Craig D

    2013-06-04

    A hydraulic valve actuation assembly may include a housing, a piston, a supply control valve, a closing control valve, and an opening control valve. The housing may define a first fluid chamber, a second fluid chamber, and a third fluid chamber. The piston may be axially secured to an engine valve and located within the first, second and third fluid chambers. The supply control valve may control a hydraulic fluid supply to the piston. The closing control valve may be located between the supply control valve and the second fluid chamber and may control fluid flow from the second fluid chamber to the supply control valve. The opening control valve may be located between the supply control valve and the second fluid chamber and may control fluid flow from the supply control valve to the second fluid chamber.

  16. Transfemoral Transcatheter Aortic Valve Replacement for Mixed Aortic Valve Disease in Child's Class C Liver Disease Prior to Orthotopic Liver Transplantation: A Case Report.

    Science.gov (United States)

    Wilkey, Barbara J; Hanson, Ross; Reece, T Brett; Forman, Lisa; Burton, James R; Messenger, John C; Kim, Michael S; Cleveland, Joseph C; Fiegel, Matt J; Nydam, Trevor L; Mandell, M Susan

    2016-06-01

    The American Association for the Study of Liver Diseases practice guidelines list severe cardiac disease as a contraindication to liver transplantation. Transcatheter aortic valve replacement has been shown to decrease all-cause mortality in patients with severe aortic stenosis who are not considered candidates for surgical aortic valve replacement. We report our experience of liver transplantation in a patient with severe aortic stenosis and moderate aortic insufficiency who underwent transcatheter aortic valve replacement with Child-Pugh Class C disease at a Model For End-Stage Liver Disease score of 29. The patient had a difficult post procedure course that was successfully medically managed. After liver transplantation the patient was discharged to home on postoperative day 11. The combination of cardiac disease and end stage liver disease is challenging but these patients can have a successful outcome despite very severe illness.

  17. Improving the pneumatic control valve performance using a PID controller

    OpenAIRE

    Heidari, Mohammad; Homaei, Hadi

    2014-01-01

    Pneumatic control valves are still the most used in process industries due to their low cost and simplicity. This paper presents a design procedure of a PID controller for a pneumatic control valve. For comparison, P and PI controllers are also utilized for the control valve. The bond graph method is used to model the control valve, in order to compare the response characteristics of the valve. Simulation results are found for three controllers of the valve. The integral time absolute error c...

  18. Transaortic aortic valve replacement using the Edwards Sapien-XT Valve and the Medtronic CoreValve: initial experience.

    Science.gov (United States)

    Spargias, Konstantinos; Bouboulis, Nikolaos; Halapas, Antonios; Chrissoheris, Michael; Skardoutsos, Spyridon; Nikolaou, Joulia; Tsolakis, Apostolos; Mourmouris, Christos; Pattakos, Stratis

    2014-01-01

    Transcatheter aortic valve replacement (TAVR) is now an established treatment for certain patients with severe aortic valve stenosis (AS). However, as the number of patients screened for TAVR increases, many are found to have absolutely no option for peripheral artery access. Transaortic valve replacement (TAoVR) has been proposed as a new alternative route in patients deemed unsuitable for conventional approaches. We present our first series of TAoVR cases using the Edwards Sapien-XT and the Medtronic CoreValve prostheses. Twenty-five (25) symptomatic patients (mean age 78 ± 8 years, mean logistic EuroSCORE I 25 ± 11%) with severe AS underwent TAoVR using the Sapien-XT valve (10 patients) or the CoreValve (15 patients). The mean fluoroscopy time was 15.6 ± 4.2 minutes, the mean time in the intensive care unit was 1.9 ± 1.0 days, and the mean hospital stay was 6.4 ± 1.6 days. The mean effective aortic valve area increased (from 0.68 ± 0.15 cm(2) to 1.82 ± 0.34 cm(2), pMedtronic CoreValve prosthesis demonstrated that it could be performed safely, resulting in substantial acute echocardiographic and early clinical improvement.

  19. Nuclear Medicine in Diagnosis of Prosthetic Valve Endocarditis: An Update

    Directory of Open Access Journals (Sweden)

    Maria Musso

    2015-01-01

    Full Text Available Over the past decades cardiovascular disease management has been substantially improved by the increasing introduction of medical devices as prosthetic valves. The yearly rate of infective endocarditis (IE in patient with a prosthetic valve is approximately 3 cases per 1,000 patients. The fatality rate of prosthetic valve endocarditis (PVE remains stable over the years, in part due to the aging of the population. The diagnostic value of echocardiography in diagnosis is operator-dependent and its sensitivity can decrease in presence of intracardiac devices and valvular prosthesis. The modified Duke criteria are considered the gold standard for diagnosing IE; their sensibility is 80%, but in clinical practice their diagnostic accuracy in PVE is lower, resulting inconclusively in nearly 30% of cases. In the last years, these new imaging modalities have gained an increasing attention because they make it possible to diagnose an IE earlier than the structural alterations occurring. Several studies have been conducted in order to assess the diagnostic accuracy of various nuclear medicine techniques in diagnosis of PVE. We performed a review of the literature to assess the available evidence on the role of nuclear medicine techniques in the diagnosis of PVE.

  20. Nuclear Medicine in Diagnosis of Prosthetic Valve Endocarditis: An Update

    Science.gov (United States)

    Musso, Maria; Petrosillo, Nicola

    2015-01-01

    Over the past decades cardiovascular disease management has been substantially improved by the increasing introduction of medical devices as prosthetic valves. The yearly rate of infective endocarditis (IE) in patient with a prosthetic valve is approximately 3 cases per 1,000 patients. The fatality rate of prosthetic valve endocarditis (PVE) remains stable over the years, in part due to the aging of the population. The diagnostic value of echocardiography in diagnosis is operator-dependent and its sensitivity can decrease in presence of intracardiac devices and valvular prosthesis. The modified Duke criteria are considered the gold standard for diagnosing IE; their sensibility is 80%, but in clinical practice their diagnostic accuracy in PVE is lower, resulting inconclusively in nearly 30% of cases. In the last years, these new imaging modalities have gained an increasing attention because they make it possible to diagnose an IE earlier than the structural alterations occurring. Several studies have been conducted in order to assess the diagnostic accuracy of various nuclear medicine techniques in diagnosis of PVE. We performed a review of the literature to assess the available evidence on the role of nuclear medicine techniques in the diagnosis of PVE. PMID:25695043

  1. Transcatheter valve-in-valve implantation due to severe aortic regurgitation in a degenerated aortic homograft

    DEFF Research Database (Denmark)

    Olsen, Lene Kjaer; Engstrøm, Thomas; Søndergaard, Lars

    2009-01-01

    Transcatheter aortic valve implantation (TAVI) in severe aortic stenosis has proven to be a feasible and effective treatment modality for inoperable patients. Until now, neither aortic regurgitation nor degenerated bioprostheses has been an indication for TAVI. However, this article reports...... a successful valve-in-valve implantation of a CoreValve aortic valve prosthesis through the right subclavian artery in a case of severe aortic regurgitation within a degenerated aortic homograft. The case exemplifies the possibilities of expanding the indications for TAVI, as well as other vascular access...

  2. Gasoline New Timing and Flux Adjustable Rotary Valve Design (Hereinafter: Rotary Valve

    Directory of Open Access Journals (Sweden)

    Du huiqi

    2016-01-01

    Full Text Available Conventional gasoline engine with an umbrella valve control cylinder intake and exhaust, in order to achieve sealing effect, the valve is driven by the spring force; at the same time, when the cam opens the valve to overcome the spring force acting. Sealing the better, the more power consumed in the engine mechanical losses, the valve mechanism consumes about 30%, which is not a small loss! This article describes a new type of rotary valve is to significantly reduce mechanical losses, so as to achieve energy saving purposes.

  3. Aortic and Mitral Valve Replacement Through a Single Transverse Aortotomy: A Useful Approach in Difficult Mitral Valve Exposure

    OpenAIRE

    Carmichael, Michael J.; Cooley, Denton A.; Favor, Arsenio S.

    1983-01-01

    Replacement of the mitral valve through a standard vertical left atriotomy in patients requiring both aortic and mitral valve replacement can be very difficult. This is especially true in patients who have undergone previous median sternotomy. Replacement of the mitral valve through the aortic root after excision of the aortic valve is described in two case reports. This is a convenient approach when traditional exposure of the mitral valve is impractical in patients requiring double valve re...

  4. Cylinder valve packing nut studies

    Energy Technology Data Exchange (ETDEWEB)

    Blue, S.C. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

    1991-12-31

    The design, manufacture, and use of cylinder valve packing nuts have been studied to improve their resistance to failure from stress corrosion cracking. Stress frozen photoelastic models have been analyzed to measure the stress concentrations at observed points of failure. The load effects induced by assembly torque and thermal expansion of stem packing were observed by strain gaging nuts. The effects of finishing operations and heat treatment were studied by the strain gage hole boring and X-ray methods. Modifications of manufacturing and operation practices are reducing the frequency of stress corrosion failures.

  5. Left atrial ball valve thrombus

    Directory of Open Access Journals (Sweden)

    R. Balaji

    2013-10-01

    Full Text Available "Ball valve thrombus" which is a spherical free floating clot in left atrium is an often quoted, but uncommonly encountered complication in patients with severe mitral stenosis of rheumatic origin, who are in atrial fibrillation. We describe the case of a 31-year-old lady with rheumatic heart disease, severe mitral stenosis and moderately severe aortic stenosis who had undergone closed mitral valvotomy 13 years ago. The patient presented with an episode of non-exertional syncope and breathlessness on exertion of 6 months duration and was in normal sinus rhythm. Echocardiography facilitated ante-mortem diagnosis and prompt institution of surgery was life saving.

  6. Standardization of phaseolus vulgaris valves by macro- and microscopic characteristics

    Directory of Open Access Journals (Sweden)

    Анна Ігорівна Крюкова

    2016-03-01

    Full Text Available During the last years on the Ukrainian pharmaceutical market a tendency to increase the range of the national herbal remedies is observed. Native flora herbs, having a sufficient resource base, deserve special attention and are characterized by a number of economic benefits for manufacturers. The implementation of herbal remedies in medical practice is accompanied by the necessity to improve the quality control of herbal material and to develop normative documents. Macro- and microscopy analysis becomes important at standardization of herbal material especially cut and powdered.Aim. The aim of our work was to carry out macro- and microscopy research of Phaseolus vulgaris and to determine its diagnostic morphologic and anatomic features.Methods. The conventional research methods in pharmacognosy have been used; photomicrography has been taken by using microscope MC-10 and Samsung PL 50 camera.Results. As a result of research, the microscopic diagnostic characteristics for Phaseolus vulgaris valves have been proposed, e.g.: the valves are elongated, straight, navicular or grooved, twisted to some extent; the external surface is smooth or slightly undulating, mat, pale yellow or yellow; the internal surface is shiny, white or yellowish-white. Sometimes carpophore (stalk may occur. The microscopic diagnostic features have been determined and offered, e.g.: cells of outer epidermis are pentagonal and hexagonal, with plicated cuticle; stomata are surrounded by 3–4 subsidiary narrow cells, additionally surrounded by 5–6 narrow cells; cover trichomes and glandular trichomes are elongated, pointed and unbranched; xylem vessels and tracheids; non-bundled structure stalk fragments with pericyclic sclerenchyma and secretory cells in the phloem.Conclusion. Research on determination of the macro- and microscopic characteristics of Phaseolus vulgaris valves has been carried out. The diagnostic morphological and anatomic elements in herbal material have

  7. On-pump fibrillating heart mitral valve replacement with the SAPIEN™ XT transcatheter heart valve.

    Science.gov (United States)

    Ferrari, Enrico; Niclauss, Lars; Locca, Didier; Marcucci, Carlo

    2014-04-01

    In some high-risk patients, standard mitral valve replacement can represent a challenging procedure, requiring a risky extensive decalcification of the annulus. In particular, high-risk redo patients and patients with a previously implanted transcatheter aortic valve, who develop calcific mitral disease, would benefit from the development of new, minimally invasive, transcatheter or hybrid techniques for mitral valve replacement. In particular, mixing transcatheter valve therapies and well-established minimally invasive techniques for mitral replacement or repair can help in decreasing the surgical risk and the technical complexity. Thus, placing transcatheter, balloon-expandable Sapien™ XT stent-valves in calcified, degenerated mitral valves through a right thoracotomy, a left atriotomy and on an on-pump fibrillating heart, represents an attractive alternative to standard surgery in redo patients, in patients with concomitant transcatheter aortic stent-valves in place and in patients with a high-risk profile. We describe this hybrid technique in detail.

  8. Fabricating PFPE Membranes for Microfluidic Valves and Pumps

    Science.gov (United States)

    Greer, Frank; White, Victor E.; Lee, Michael C.; Willis, Peter A.; Grunthaner, Frank J.; Rolland, Jason; Rolland, Jason

    2009-01-01

    A process has been developed for fabricating membranes of a perfluoropolyether (PFPE) and integrating them into valves and pumps in laboratory-on-achip microfluidic devices. Membranes of poly(tetrafluoroethylene) [PTFE] and poly(dimethylsilane) [PDMS] have been considered for this purpose and found wanting. By making it possible to use PFPE instead of PTFE or PDMS, the present process expands the array of options for further development of microfluidic devices for diverse applications that could include detection of biochemicals of interest, detection of toxins and biowarfare agents, synthesis and analysis of proteins, medical diagnosis, and synthesis of fuels.

  9. Aortic valve endocarditis complicated by ST-elevation myocardial infarction.

    Science.gov (United States)

    Jenny, Benjamin E; Almanaseer, Yassar

    2014-12-01

    Infective endocarditis complicated by abscess formation and coronary artery compression is a rare clinical event with a high mortality rate, and diagnosis requires a heightened degree of suspicion. We present the clinical, angiographic, and echocardiographic features of a 73-year-old woman who presented with dyspnea and was found to have right coronary artery compression that was secondary to abscess formation resulting from diffuse infectious endocarditis. We discuss the patient's case and briefly review the relevant medical literature. To our knowledge, this is the first reported case of abscess formation involving a native aortic valve and the right coronary artery.

  10. Predictors of mortality after aortic valve replacement

    NARCIS (Netherlands)

    Tjang, Yanto Sandy; van Hees, Yvonne; Koerfer, Reiner; Grobbee, Diederick E.; van der Heijden, Geert J. M. G.

    Aortic valve replacement (AVR) is recommended as a standard surgical procedure for aortic valve disease. Still the evidence for commonly claimed predictors of post-AVR prognosis, in particular mortality, appears scant. This systematic review reports on the evidence for predictors of post-AVR

  11. Numerical Analysis of Large Diameter Butterfly Valve

    Science.gov (United States)

    Youngchul, Park; Xueguan, Song

    In this paper, a butterfly valve with the diameter of 1,800 mm was studied. Three-dimensional numerical technique by using commercial code CFX were conducted to observe the flow patterns and to measure flow coefficient, hydrodynamic torque coefficient and so on, when the large butterfly valve operated with various angles and uniform incoming velocity.

  12. 49 CFR 195.420 - Valve maintenance.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Valve maintenance. 195.420 Section 195.420 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... PIPELINE Operation and Maintenance § 195.420 Valve maintenance. (a) Each operator shall maintain each...

  13. A highly sensitive spin-valve transistor

    NARCIS (Netherlands)

    Erve, van 't O.M.J.; Vlutters, R.; Anil Kumar, P.S.; Kim, S.D.; Jansen, R.; Lodder, J.C.; Hadjipanayis, G.C.

    2001-01-01

    In this paper we present a spin-valve transistor made with a silicon on insulator wafer as emitter and a double sided polished Si wafer as collector. Using vacuum metal bonding we obtain a three terminal device in which a spin-valve layer is sandwiched between two Si wafers. We measure a 217% change

  14. Mitral valve repair in acquired dextrocardia.

    Science.gov (United States)

    Elmistekawy, Elsayed; Chan, Vincent; Hynes, Mark; Mesana, Thierry

    2015-10-01

    Surgical correction of valvular heart disease in patients with dextrocardia is extremely rare. We report a surgical case of mitral valve repair in a patient with acquired dextrocardia. Successful mitral valve repair was performed through a right lateral thoracotomy. We describe our surgical strategy and summarize the literature.

  15. Whole Teflon valves for handling droplets.

    Science.gov (United States)

    Cybulski, Olgierd; Jakiela, Slawomir; Garstecki, Piotr

    2016-06-21

    We propose and test a new whole-Teflon gate valve for handling droplets. The valve allows droplet plugs to pass through without disturbing them. This is possible due to the geometric design, the choice of material and lack of any pulses of flow generated by closing or opening the valve. The duct through the valve resembles a simple segment of tubing, without constrictions, change in lumen or side pockets. There are no extra sealing materials with different wettability or chemical resistance. The only material exposed to liquids is FEP Teflon, which is resistant to aggressive chemicals and fully biocompatible. The valve can be integrated into microfluidic systems: we demonstrate a complex system for culturing bacteria in hundreds of microliter droplet chemostats. The valve effectively isolates modules of the system to increase precision of operations on droplets. We verified that the valve allowed millions of droplet plugs to safely pass through, without any cross-contamination with bacteria between the droplets. The valve can be used in automating complex microfluidic systems for experiments in biochemistry, biology and organic chemistry.

  16. 46 CFR 64.67 - Shutoff valve.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Shutoff valve. 64.67 Section 64.67 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.67 Shutoff valve. A shutoff...

  17. Digital hydraulic valving system. [design and development

    Science.gov (United States)

    1973-01-01

    The design and development are reported of a digital hydraulic valving system that would accept direct digital inputs. Topics include: summary of contractual accomplishments, design and function description, valve parameters and calculations, conclusions, and recommendations. The electrical control circuit operating procedure is outlined in an appendix.

  18. Oil pipeline valve automation for spill reduction

    Energy Technology Data Exchange (ETDEWEB)

    Mohitpour, Mo; Trefanenko, Bill [Enbridge Technology Inc, Calgary (Canada); Tolmasquim, Sueli Tiomno; Kossatz, Helmut [TRANSPETRO - PETROBRAS Transporte S.A., Rio de Janeiro, RJ (Brazil)

    2003-07-01

    Liquid pipeline codes generally stipulate placement of block valves along liquid transmission pipelines such as on each side of major river crossings where environmental hazards could cause or are foreseen to potentially cause serious consequences. Codes, however, do not stipulate any requirement for block valve spacing for low vapour pressure petroleum transportation, nor for remote pipeline valve operations to reduce spills. A review of pipeline codes for valve requirement and spill limitation in high consequence areas is thus presented along with a criteria for an acceptable spill volume that could be caused by pipeline leak/full rupture. A technique for deciding economically and technically effective pipeline block valve automation for remote operation to reduce oil spilled and control of hazards is also provided. In this review, industry practice is highlighted and application of the criteria for maximum permissible oil spill and the technique for deciding valve automation thus developed, as applied to ORSUB pipeline is presented. ORSUB is one of the three initially selected pipelines that have been studied. These pipelines represent about 14% of the total length of petroleum transmission lines operated by PETROBRAS Transporte S.A. (TRANSPETRO) in Brazil. Based on the implementation of valve motorization on these three pipeline, motorization of block valves for remote operation on the remaining pipelines is intended, depending on the success of these implementations, on historical records of failure and appropriate ranking. (author)

  19. Inexpensive tamper proof safety relief valve

    Science.gov (United States)

    Frankewich, P. A.

    1970-01-01

    Basic relief valve has added safety relief valve capability that relieves overpressure before failure can occur. It may be installed in inaccesible areas with a high degree of reliability, constructed from a variety of materials, and adapted to the user's specific application.

  20. Heart Valve Disease among Patients with Hyperprolactinaemia

    DEFF Research Database (Denmark)

    Steffensen, Charlotte; Maegbaek, Merete Lund; Laurberg, Peter;

    2012-01-01

    Increased risk of heart valve disease during treatment with certain dopamine agonists, such as cabergoline, has been observed in patients with Parkinson's disease. The same compound is used to treat hyperprolactinemia, but it is unknown whether this also associates with heart valve disease....

  1. Mitral valve disease—morphology and mechanisms

    Science.gov (United States)

    Levine, Robert A.; Hagége, Albert A.; Judge, Daniel P.; Padala, Muralidhar; Dal-Bianco, Jacob P.; Aikawa, Elena; Beaudoin, Jonathan; Bischoff, Joyce; Bouatia-Naji, Nabila; Bruneval, Patrick; Butcher, Jonathan T.; Carpentier, Alain; Chaput, Miguel; Chester, Adrian H.; Clusel, Catherine; Delling, Francesca N.; Dietz, Harry C.; Dina, Christian; Durst, Ronen; Fernandez-Friera, Leticia; Handschumacher, Mark D.; Jensen, Morten O.; Jeunemaitre, Xavier P.; Le Marec, Hervé; Le Tourneau, Thierry; Markwald, Roger R.; Mérot, Jean; Messas, Emmanuel; Milan, David P.; Neri, Tui; Norris, Russell A.; Peal, David; Perrocheau, Maelle; Probst, Vincent; Pucéat, Michael; Rosenthal, Nadia; Solis, Jorge; Schott, Jean-Jacques; Schwammenthal, Ehud; Slaugenhaupt, Susan A.; Song, Jae-Kwan; Yacoub, Magdi H.

    2016-01-01

    Mitral valve disease is a frequent cause of heart failure and death. Emerging evidence indicates that the mitral valve is not a passive structure, but—even in adult life—remains dynamic and accessible for treatment. This concept motivates efforts to reduce the clinical progression of mitral valve disease through early detection and modification of underlying mechanisms. Discoveries of genetic mutations causing mitral valve elongation and prolapse have revealed that growth factor signalling and cell migration pathways are regulated by structural molecules in ways that can be modified to limit progression from developmental defects to valve degeneration with clinical complications. Mitral valve enlargement can determine left ventricular outflow tract obstruction in hypertrophic cardiomyopathy, and might be stimulated by potentially modifiable biological valvular–ventricular interactions. Mitral valve plasticity also allows adaptive growth in response to ventricular remodelling. However, adverse cellular and mechanobiological processes create relative leaflet deficiency in the ischaemic setting, leading to mitral regurgitation with increased heart failure and mortality. Our approach, which bridges clinicians and basic scientists, enables the correlation of observed disease with cellular and molecular mechanisms, leading to the discovery of new opportunities for improving the natural history of mitral valve disease. PMID:26483167

  2. Mitral valve disease--morphology and mechanisms.

    Science.gov (United States)

    Levine, Robert A; Hagége, Albert A; Judge, Daniel P; Padala, Muralidhar; Dal-Bianco, Jacob P; Aikawa, Elena; Beaudoin, Jonathan; Bischoff, Joyce; Bouatia-Naji, Nabila; Bruneval, Patrick; Butcher, Jonathan T; Carpentier, Alain; Chaput, Miguel; Chester, Adrian H; Clusel, Catherine; Delling, Francesca N; Dietz, Harry C; Dina, Christian; Durst, Ronen; Fernandez-Friera, Leticia; Handschumacher, Mark D; Jensen, Morten O; Jeunemaitre, Xavier P; Le Marec, Hervé; Le Tourneau, Thierry; Markwald, Roger R; Mérot, Jean; Messas, Emmanuel; Milan, David P; Neri, Tui; Norris, Russell A; Peal, David; Perrocheau, Maelle; Probst, Vincent; Pucéat, Michael; Rosenthal, Nadia; Solis, Jorge; Schott, Jean-Jacques; Schwammenthal, Ehud; Slaugenhaupt, Susan A; Song, Jae-Kwan; Yacoub, Magdi H

    2015-12-01

    Mitral valve disease is a frequent cause of heart failure and death. Emerging evidence indicates that the mitral valve is not a passive structure, but--even in adult life--remains dynamic and accessible for treatment. This concept motivates efforts to reduce the clinical progression of mitral valve disease through early detection and modification of underlying mechanisms. Discoveries of genetic mutations causing mitral valve elongation and prolapse have revealed that growth factor signalling and cell migration pathways are regulated by structural molecules in ways that can be modified to limit progression from developmental defects to valve degeneration with clinical complications. Mitral valve enlargement can determine left ventricular outflow tract obstruction in hypertrophic cardiomyopathy, and might be stimulated by potentially modifiable biological valvular-ventricular interactions. Mitral valve plasticity also allows adaptive growth in response to ventricular remodelling. However, adverse cellular and mechanobiological processes create relative leaflet deficiency in the ischaemic setting, leading to mitral regurgitation with increased heart failure and mortality. Our approach, which bridges clinicians and basic scientists, enables the correlation of observed disease with cellular and molecular mechanisms, leading to the discovery of new opportunities for improving the natural history of mitral valve disease.

  3. Transcatheter Aortic Valve Replacement in Europe

    DEFF Research Database (Denmark)

    Mylotte, Darren; Osnabrugge, Ruben L J; Windecker, Stephan;

    2013-01-01

    The authors sought to examine the adoption of transcatheter aortic valve replacement (TAVR) in Western Europe and investigate factors that may influence the heterogeneous use of this therapy.......The authors sought to examine the adoption of transcatheter aortic valve replacement (TAVR) in Western Europe and investigate factors that may influence the heterogeneous use of this therapy....

  4. Repair for acquired aortic valve disease.

    Science.gov (United States)

    Antunes, M J

    1996-10-01

    The favorable results of mitral valvuloplasty when compared with valve replacement have renewed the interest of many surgeons in aortic valve repair. However, these efforts have, for the most part, been unsuccessful. Also, the results of aortic valve replacement are usually better than those of mitral valve replacement. Yet, some patients appear to derive benefit from a conservative aortic valve procedure. The best examples are mild or moderate aortic valve disease associated with mitral valve or coronary artery disease, which constitute the primary indication for operation, where "prophylactic" aortic valve replacement does not appear justifiable. Other possible indications for aortic valvuloplasty includes patient's lack of compliance or contraindication to anticoagulation in young patients. Senile aortic stenosis, in very old patients with a small annulus, preserved leaflet morphology and nonsignificant commissural fusion should be considered for repair. However, since the procedure is not easily reproducible and the results not uniformly predictable, it cannot be recommended for generalized use. Nonetheless, experienced surgeons should be encouraged to continue these efforts.

  5. Transcatheter aortic valve replacement in elderly patients

    Institute of Scientific and Technical Information of China (English)

    Dimytri Siqueira; Alexandre Abizaid; Magaly Arrais J.; Eduardo Sousa

    2012-01-01

    Aortic stenosis is the most common native valve disease, affecting up to 5% of the elderly population. Surgical aortic valve replacement reduces symptoms and improves survival, and is the definitive therapy in patients with symptomatic severe aortic stenosis. However, despite the good results of classic surgery, risk is markedly increased in elderly patients with co-morbidities. Transcatheter aortic valve replacement (TAVR) allows implantation of a prosthetic heart valve within the diseased native aortic valve without the need for open heart surgery and cardiopulmonary bypass, offering a new therapeutic option to elderly patients considered at high surgical risk or with contraindications to surgery. To date, several multicenter registries and a randomized trial have confirmed the safety and efficacy of TAVR in those patients. In this chapter, we review the background and clinical applications of TAVR in elderly patients.

  6. Aortic Root Enlargement or Sutureless Valve Implantation?

    Directory of Open Access Journals (Sweden)

    Nikolaos G. Baikoussis

    2016-11-01

    Full Text Available Aortic valve replacement (AVR in patients with a small aortic annulus is a challenging issue. The importance of prosthesis–patient mismatch (PPM post aortic valve replacement (AVR is controversial but has to be avoided. Many studies support the fact that PPM has a negative impact on short and long term survival. In order to avoid PPM, aortic root enlargement may be performed. Alternatively and keeping in mind that often some comorbidities are present in old patients with small aortic root, the Perceval S suturelles valve implantation could be a perfect solution. The Perceval sutureless bioprosthesis provides reasonable hemodynamic performance avoiding the PPM and providing the maximum of aortic orifice area. We would like to see in the near future the role of the aortic root enlargement techniques in the era of surgical implantation of the sutureless valve (SAVR and the transcatheter valve implantation (TAVI.

  7. [Interventional mitral valve replacement. Current status].

    Science.gov (United States)

    Lutter, G; Frank, D

    2016-02-01

    Approximately 30 % of patients suffering from severe valvular heart disease, such as mitral valve regurgitation are non-compliant to the gold standard of minimally invasive surgery, reconstruction or valve replacement. The number of these mostly old patients with severe comorbidities is increasing; therefore, transcatheter interventions have been developed to address an unmet clinical need and may be an alternative therapeutic option to the reference standard. Apart from the successful MitraClip therapy, alternative transcatheter reconstruction technologies are being developed. As with transcatheter aortic valve implantation (TAVI) procedures, the off-pump implantation of a valved stent into the mitral position mainly via a transapical approach will be of great benefit. Recently, the feasibility of transcatheter mitral valved stent implantation in high-risk patients has already been reported.

  8. Comments on compressible flow through butterfly valves

    Science.gov (United States)

    Blakenship, John G.

    In the flow analysis of process piping systems, it is desirable to treat control valves in the same way as elbow, reducers, expansions, and other pressure loss elements. In a recently reported research program, the compressible flow characteristics of butterfly valves were investigated. Fisher Controls International, Inc., manufacturer of a wide range of control valves, publishes coefficients that can be used to calculate flow characteristics for the full range of valve movement. The use is described of the manufacturer's data to calculate flow parameters as reported by the researchers who investigated compressible flow through butterfly valves. The manufacturer's data produced consistent results and can be used to predict choked flow and the pressure loss for unchoked flow.

  9. Multidisciplinary optimization of a butterfly valve.

    Science.gov (United States)

    Song, Xue Guan; Wang, Lin; Baek, Seok Heum; Park, Young Chul

    2009-07-01

    A butterfly valve is a type of flow control device, typically used to regulate fluid flow. This paper proposes a new process to meet desired needs in valve design that is characterized by the complex configuration. First, the need is identified according to the valve user/company, and then the problem is defined with a characteristic function. Second, the initial model of valve is made, and then the initial analysis including fluid and/or structural analysis is carried out to predict the fluid and/or structural performance of the valve. Third, the optimization in the form of mathematical functions, which considers single or multiple objective and/or discipline, is handled. This part includes the design of computer experiment, approximation technique, topology optimization and sizing optimization. Finally, the validation experiment is conducted based on the optimum result to verify the accuracy of the optimization. An example is provided to confirm the availability of the process proposed here.

  10. Transcatheter mitral valve implantation via transapical approach

    DEFF Research Database (Denmark)

    Sondergaard, Lars; Brooks, Matthew; Ihlemann, Nikolaj;

    2015-01-01

    OBJECTIVES: As many as 50% of patients with severe symptomatic mitral valve regurgitation are denied surgical valve replacement or repair due to high operative risk. We describe an early series of cases of transcatheter implantation with a CardiAQ™ mitral valve via a transapical approach. METHODS......: Three consecutive patients with an Society of Thoracic Surgeons (STS) mortality score of >22% were selected for transcatheter mitral valve implantation (TMVI) on compassionate grounds. All patients were elderly, had severe mitral regurgitation (MR), were in Class IV heart failure and deemed unsuitable...... bypass surgery (n = 2), severe pulmonary hypertension (n = 1) and moderate to severe chronic renal failure (n = 3). A CardiAQ mitral valve was implanted using fluoroscopy and transoesophageal (TEE) guidance via a standard transapical approach. RESULTS: Accurate prosthesis positioning and deployment...

  11. An unusual case of Bjork-Shiley mitral valve dysfunction corrected nonsurgically.

    Science.gov (United States)

    DePace, N L; Burke, W; Kotler, M N; Glazier, E E

    1981-10-01

    A case of Bjork-Shiley mitral valve dysfunction is presented. The patient has not responded to anticoagulant therapy and had hypotension, dyspnea, chest pain, and a pulse deficit but normal sinus rhythm. Simultaneous echocardiogram, ECG, and arterial pulse tracing were used as noninvasive means of monitoring. Nonsurgical correction of a clinical emergency restored the patient to prior normal baseline cardiovascular function. This case illustrates the possibility of restoring normal prosthetic function by supporting the patient medically while undertaking diagnostic testing and arranging surgical intervention. To our knowledge, this is the first reported case of a malfunctioning Bjork-Shiley mitral valve corrected without surgery.

  12. Transcatheter aortic valve-in-valve implantation of a CoreValve in a degenerated aortic bioprosthesis.

    Science.gov (United States)

    Bruschi, Giuseppe; DeMarco, Federico; Oreglia, Jacopo; Colombo, Paola; Fratto, Pasquale; Lullo, Francesca; Paino, Roberto; Martinelli, Luigi; Klugmann, Silvio

    2010-03-01

    In recent years percutaneous aortic valve implantation has emerged as an alternative therapy to treat patients with symptomatic aortic stenosis considered to be high-risk surgical candidates. We report our experience of a percutaneous retrograde CoreValve implantation in a 77-year-old female with aortic bioprosthesis structural degeneration. The patient underwent aortic valve replacement for aortic stenosis in 1999 with the implantation of a 23 mm Carpentier-Edwards; her last echocardiography showed a severe bioprosthesis stenosis. After evaluation by cardiac surgeons and cardiologist, considering the high risk re-do surgical procedure (Logistic Euroscore 30%) and severe comorbidities (severe pulmonary hypertension, hepatocellular carcinoma and severe osteoporosis), a percutaneous aortic valve-in-valve replacement was preferred. A successful percutaneous 26 mm CoreValve prosthesis implantation was performed with the patient awake with local anesthesia and mild sedation. The patient was discharged after 10 days of hospitalization and she is in NYHA functional class I at follow-up. Our experience, characterized by a multidisciplinary approach, necessary to offer the safest conditions and care for patients, demonstrates the feasibility of a new, promising indication for the use of a transcatheter valve implantation: percutaneous treatment of a degenerated aortic bioprosthesis.

  13. Posttraumatic tricuspid valve injury and severe tricuspid valve regurgitation.

    Science.gov (United States)

    Gucuk Ipek, Esra

    2013-09-01

    A 66-year-old male was brought to our hospital following a car accident. He had subarachnoid hemorrhage, multiple rib fractures, and left hemopneumothorax. He was referred to the Cardiology Department for elevated troponin levels (42 ng/ml, reference 0-1 ng/ml). The electrocardiogram was free of ischemia, whereas the transthoracic echocardiography revealed dilated right heart chambers, enlarged tricuspid annulus and coaptation failure of the tricuspid valvular leaflets. There was rupture on the subvalvular apparatus of the anterior leaflet of the tricuspid valve with accompanying prolapse, causing severe tricuspid valvular regurgitation. The patient did not present right ventricular failure signs and symptoms; he was referred to surgery after the resolution of associated thoracic and cranial injuries.

  14. THE RESULTS OF SURGICAL TREATMENT OF TRICUSPID VALVE INFECTIVE ENDOCARDITIS USING VALVE REPAIR AND VALVE REPLACEMENT OPERATIONS

    Directory of Open Access Journals (Sweden)

    S. A. Kovalev

    2015-01-01

    Full Text Available Aim. To evaluate in-hospital and long-term results of surgical treatment of patients with infective endocarditis of the tricuspid valve, to compare the effectiveness of valve repair and valve replacement techniques, and to identify risk factors of mortality and reoperations. Materials and methods. 31 surgical patients with tricuspid valve infective endocarditis were evaluated. Patients were divided into 2 groups. In Group 1 (n = 14 repairs of the tricuspid valve were performed, in Group 2 (n = 17 patients had undergone tricuspid valve replacements. Epidemiological, clinical, microbiological and echocardiographic data were studied. Methods of comparative analysis, the Kaplan–Meier method, and Cox risk models were applied. Results. The most common complication of in-hospital stay was atrioventricular block (17.7% of cases in Group 2. In Group 1, this type of complication was not found. Hospital mortality was 7.14% in Group 1, and 0% in Group 2. Long-term results have shown the significant reduction of heart failure in general cohort and in both groups. In Group 1 the severity of heart failure in the long term was less than in Group 2. No significant differences in the severity of tricuspid regurgitation were found between the groups. In 7-year follow up no cases of death were registered in Group 1. Cumulative survival rate in Group 2 within 60 months was 67.3 ± 16.2%. No reoperations were performed in patients from Group 1. In Group 2, the freedom from reoperation within 60 months was 70.9 ± 15.3%. Combined intervention was found as predictor of postoperative mortality. Prosthetic valve endocarditis was identified as risk factor for reoperation. Conclusion. Valve repair and valve replacement techniques of surgical treatment of tricuspid valve endocarditis can provide satisfactory hospital and long-term results. Tricuspid valve repair techniques allowed reducing the incidence of postoperative atrioventricular block. In the long-term, patients

  15. Whitey SCHe Ball Valves Provide Test Port Isolation

    Energy Technology Data Exchange (ETDEWEB)

    MISKA, C.R.

    2000-09-15

    These valves are 1/4 inch ball valves fabricated of 316 stainless steel. Packing is TFE (standard). They are used as normally closed isolation valves for test ports in the SCHe System between the gage root valve and the pressure indicator.

  16. 49 CFR 192.181 - Distribution line valves.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Distribution line valves. 192.181 Section 192.181... line valves. (a) Each high-pressure distribution system must have valves spaced so as to reduce the time to shut down a section of main in an emergency. The valve spacing is determined by the...

  17. 46 CFR 105.25-20 - Shutoff valves required.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Shutoff valves required. 105.25-20 Section 105.25-20... Installed Below Decks § 105.25-20 Shutoff valves required. (a) Shutoff valves shall be provided in the suction lines as close to the tanks as possible. The valves shall be installed so as to shut off...

  18. 46 CFR 154.1125 - Pipes, fittings, and valves.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Pipes, fittings, and valves. 154.1125 Section 154.1125... Firefighting § 154.1125 Pipes, fittings, and valves. (a) Each pipe, fitting, and valve for each water spray... listed in § 154.1110 must have at least one isolation valve at each branch connection and at least...

  19. 46 CFR 154.806 - Capacity of pressure relief valves.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Capacity of pressure relief valves. 154.806 Section 154... Equipment Cargo Vent Systems § 154.806 Capacity of pressure relief valves. Pressure relief valves for each... pressure above the set pressure of the relief valves: (a) The maximum capacity of an installed cargo...

  20. 46 CFR 78.17-5 - Valves and closing appliances.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Valves and closing appliances. 78.17-5 Section 78.17-5..., Drills, and Inspections § 78.17-5 Valves and closing appliances. (a) It shall be the duty of the master to see that all valves, including cross connecting valves where fitted, and other appliances such...

  1. 46 CFR 153.368 - Pressure-vacuum valves.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Pressure-vacuum valves. 153.368 Section 153.368 Shipping... Systems § 153.368 Pressure-vacuum valves. (a) The pressure side of a required pressure-vacuum relief valve... relief valve must meet the requirements of Subpart 162.017 of this chapter....

  2. 46 CFR 98.25-40 - Valves, fittings, and accessories.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Valves, fittings, and accessories. 98.25-40 Section 98... Anhydrous Ammonia in Bulk § 98.25-40 Valves, fittings, and accessories. (a) All valves, flanges, fittings... Engineering) of this chapter. Valves shall be fitted with noncorrosive material suitable for ammonia...

  3. 46 CFR 56.20-9 - Valve construction.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Valve construction. 56.20-9 Section 56.20-9 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PIPING SYSTEMS AND APPURTENANCES Valves § 56.20-9 Valve construction. (a) Each valve must close with a right-hand...

  4. Motor operated valves problems tests and simulations

    Energy Technology Data Exchange (ETDEWEB)

    Pinier, D.; Haas, J.L.

    1996-12-01

    An analysis of the two refusals of operation of the EAS recirculation shutoff valves enabled two distinct problems to be identified on the motorized valves: the calculation methods for the operating torques of valves in use in the power plants are not conservative enough, which results in the misadjustement of the torque limiters installed on their motorizations, the second problem concerns the pressure locking phenomenon: a number of valves may entrap a pressure exceeding the in-line pressure between the disks, which may cause a jamming of the valve. EDF has made the following approach to settle the first problem: determination of the friction coefficients and the efficiency of the valve and its actuator through general and specific tests and models, definition of a new calculation method. In order to solve the second problem, EDF has made the following operations: identification of the valves whose technology enables the pressure to be entrapped: the tests and numerical simulations carried out in the Research and Development Division confirm the possibility of a {open_quotes}boiler{close_quotes} effect: determination of the necessary modifications: development and testing of anti-boiler effect systems.

  5. Heart Valve Biomechanics and Underlying Mechanobiology

    Science.gov (United States)

    Ayoub, Salma; Ferrari, Giovanni; Gorman, Robert C.; Gorman, Joseph H.; Schoen, Frederick J.; Sacks, Michael S.

    2017-01-01

    Heart valves control unidirectional blood flow within the heart during the cardiac cycle. They have a remarkable ability to withstand the demanding mechanical environment of the heart, achieving lifetime durability by processes involving the ongoing remodeling of the extracellular matrix. The focus of this review is on heart valve functional physiology, with insights into the link between disease-induced alterations in valve geometry, tissue stress, and the subsequent cell mechanobiological responses and tissue remodeling. We begin with an overview of the fundamentals of heart valve physiology and the characteristics and functions of valve interstitial cells (VICs). We then provide an overview of current experimental and computational approaches that connect VIC mechanobiological response to organ- and tissue-level deformations and improve our understanding of the underlying functional physiology of heart valves. We conclude with a summary of future trends and offer an outlook for the future of heart valve mechanobiology, specifically, multiscale modeling approaches, and the potential directions and possible challenges of research development. PMID:27783858

  6. Safety/relief-valve test program

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, J.A.

    1982-01-01

    In response to the NRC's Task 2.1.2 following the TMI-2 accident, government and industry programs were formulated to address the performance of safety and relief valve systems for pressurized and boiling water reactors. Objective is to demonstrate by testing and analysis that safety and relief valve systems in the reactor coolant system are qualified for the anticipated full range of reactor operating and accident conditions. The EPRI PWR program tested PWR safety valves and power operated relief valves (PORVs) under steam, liquid, and steam/liquid transition conditions. The program also tested PWR PORV block valves under steam conditions. The GE BWR program tested BWR relief and safety/relief valves under high pressure steam and low pressure liquid conditions. EG and G Idaho recent activities have focused on the evaluation of the industry test data, evaluation and modification of analytical codes for safety/relief valve system analysis, and initial evaluation of utility responses to US NRC program requirements.

  7. Are valve repairs associated with better outcomes than replacements in patients with native active valve endocarditis?

    Science.gov (United States)

    Zhao, Dong; Zhang, Benqing

    2014-12-01

    A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether valve replacement was associated with higher morbidity and mortality rates than valve repair in patients with native active valve endocarditis. Altogether 662 papers were found using the reported search, of which 7 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Traditionally, valve replacement has been the standard therapy for valve endocarditis when surgical treatment is indicated. But now valve repair is increasingly used as an alternative, which may avoid disadvantages of anticoagulation, lower the risk of prosthetic infection and improve postoperative survival. To compare outcomes of these two treatments between studies can be difficult because most of related papers contain raw data on prosthetic valve endocarditis or healed endocarditis, which were excluded from our manuscript. Studies only analysing the outcomes of either of these treatments without the comparison of valve repair and replacement were also excluded. Finally, seven papers were identified. The American Heart Association/American College of Cardiology 2006 valvular guidelines recommended that mitral valve repair should be performed instead of replacement when at all possible. In three of the seven studies, there were significant differences between valve repair and replacement in long-term survival. One study found that aortic valve repair offered better outcomes in freedom from reoperation at 5 years (P = 0.021) and in survival at 4 years (repair vs replacement 88 vs 65%; P = 0.047). One study reported that there was improved event-free survival at 10 years in the mitral valve repair group (P = 0.015), although there was more previous septic embolization in this group. In one study, early and late mortality

  8. A study of ISO Solenoid Valve with static and dynamic characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Y. S.; Ju, M. J.; Oh, Y. C. [FAMCO Ltd, Gyeongju (Korea, Republic of); Kim, D. S. [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2009-07-01

    The technology of ISO Solenoid Valves is now considered as a core technology in the fields of the production line of semi-conductor chips and the ISO fluid chips for medical applications. And ISO Solenoid Valves, which operate by compressed air, are characterized by high speed response, great repeatability and that the pressure on the cross sectional area of poppet is kept constant regardless of the fluctuation of the pressure exerted on the ports. The primary objective of this study is to compare the optimally designed Solenoid Valve with the actually produced one and to design a power saving circuit which can highly improve the efficiency by providing optimal current according to mechanical load.

  9. Effect of mitral valve prosthesis design and orientation on intraventricular flow and blood stasis

    Science.gov (United States)

    May-Newman, Karen; Campos, J.; Montes, R.; Ramesh, V.; Moon, J.; Reider, C.; Martinez-Legazpi, P.; Bermejo, J.; Rossini, Lorenzo; Del Alamo, Juan C.

    2016-11-01

    Abnormal blood flow patterns are linked with thromboembolism (TE), especially in the presence of medical devices such as mitral valve prostheses (MVP). We performed PIV on a customized silicone left ventricle (LV) in a mock circulatory loop. We measured the velocity field in the long-axis midplane for 3 different MVP: a porcine bioprosthesis (BP), a tilting disk valve in two orientations: towards the LV lateral (TD-L) or the anterior wall (TD-A), and a bileaflet valve with anti-anatomical orientation (BL). Diastolic LV vortices were tracked and related to measures of blood stasis based on LV residence time. The BP and the TD-L produced flow patterns similar to those measured in patients. The TD-A showed a complete reversal of diastolic vortices. The BL design had increased apical blood stasis, which may lead to increased TE risk.

  10. Heart Team therapeutic decision-making and treatment in severe aortic valve stenosis

    DEFF Research Database (Denmark)

    Thyregod, Hans Gustav Hørsted; Holmberg, Fredrik; Gerds, Thomas Alexander

    2016-01-01

    Objectives: After transcatheter aortic valve implantation (TAVI) has been available for high-risk patients with severe aortic valve stenosis (AVS), the decision-making of the Heart Team (HT) has not been examined. Design: All adult patients with severe AVS referred to a large tertiary medical......%), and surgical aortic valve replacement (SAVR) in 392 (81%) of patients. In patients referred to intervention, TAVI compared with SAVR patients were older (OR = 1.17 per year, 95% CI 1.09-1.26; p obesity (OR = 4.69, 1.......51-13.77; p disease (COPD) (OR = 3.66, 1.21-10.75; p = 0.02). MT patients compared with patients referred to any intervention were older, had a higher prevalence of COPD, peripheral arterial disease, previous myocardial infarction, and cerebrovascular disease...

  11. [Chest pain with ischemic electrocardiographic changes: mitral valve prolapse in pediatrics. Case report].

    Science.gov (United States)

    Matamala-Morillo, Miguel Ángel; Rodríguez-González, Moisés; Segado-Arenas, Antonio

    2015-01-01

    Chest pain is rare and usually benign in pediatrics. Cardiac etiology is even rarer. However, it is a symptom associated with ischemic heart disease and it imposes great social alarm, even in health care workers. Therefore, it is necessary to know the most common causes of this symptom in children, as well as serious diseases that can cause it, which require prompt medical attention. We report a case of chest pain associated with ischemic electrocardiographic changes in a patient with mitral valve prolapse and MASS phenotype (mitral valve prolapse, aortic root enlargement, and skeletal and skin alterations), we review the mitral valve prolapse and stress the importance of knowing it in the pediatric setting.

  12. [Unicuspid Aortic Valve Stenosis Combined with Aortic Coarctation;Report of a Case].

    Science.gov (United States)

    Kubota, Takehiro; Wakasa, Satoru; Shingu, Yasushige; Matsui, Yoshiro

    2016-06-01

    Unicuspid aortic valve in an adult is extremely rare. In addition, 90% of the patients with aortic coarctation are reported to die before the age 50. A 60-year-old woman was admitted to our hospital for further examination of exertional dyspnea which had begun one year before. She had been under medical treatment for hypertension since early thirties, and had been also diagnosed with moderate aortic stenosis at 50 years of age. She was at 1st diagnosed with aortic coarctation combined with bicuspid aortic valve stenosis. The aortic valve was then found unicuspid and was replaced under cardiopulmonary bypass with perfusion to both the ascending aorta and the femoral artery. Repair of aortic coarctation was performed 3 months later through left thoracotomy without extracorporeal circulation due to the rich collateral circulation. She had no postoperative complications, and hypertension as well as ankle-brachial index improved to the normal levels.

  13. Aorto-right atrial fistula: Late complication of tricuspid valve infective endocarditis

    Institute of Scientific and Technical Information of China (English)

    Pedro; A; Villablanca; Shashvat; Sukhal; Oscar; Maitas; Afiachuukwu; Onuegbu; Juan; M; Muoz-Pea; Ajay; Joseph; Carlos; Requena; Divyanshu; Mohananey

    2014-01-01

    Abnormal connections between the ascending aortaand the cardiac chambers are rare, especially in thecontext of right-sided infective endocarditis(IE). Trans-thoracic echocardiography(TTE) with color-flow Dop-pler, transesophageal echocardiography(TEE), or bothmay be required for diagnosis. We present the case ofa woman admitted with right-sided heart failure(HF)symptoms. She had a previous history of tricuspid valveIE 30 years ago. TTE and TEE revealed an aorto-rightatrium fistula located just under the non-coronary cuspinto the right atrium at the level of the previously af-fected tricuspid valve. The Patient refused surgery andwas discharged home on HF medications. She has beenstable for the last 3 years. The peculiarity of this caseis the late symptomatic presentation of the aorto-atrialfistula and the unusual association to tricuspid valve IE.

  14. A novel implantable glaucoma valve using ferrofluid.

    Directory of Open Access Journals (Sweden)

    Eleftherios I Paschalis

    Full Text Available PURPOSE: To present a novel design of an implantable glaucoma valve based on ferrofluidic nanoparticles and to compare it with a well-established FDA approved valve. SETTING: Massachusetts Eye & Ear Infirmary, Boston, USA. METHODS: A glaucoma valve was designed using soft lithography techniques utilizing a water-immiscible magnetic fluid (ferrofluid as a pressure-sensitive barrier to aqueous flow. Two rare earth micro magnets were used to calibrate the opening and closing pressure. In-vitro flow measurements were performed to characterize the valve and to compare it to Ahmed™ glaucoma valve. The reliability and predictability of the new valve was verified by pressure/flow measurements over a period of three months and X-ray diffraction (XRD analysis over a period of eight weeks. In vivo assessment was performed in three rabbits. RESULTS: In the in vitro experiments, the opening and closing pressures of the valve were 10 and 7 mmHg, respectively. The measured flow/pressure response was linearly proportional and reproducible over a period of three months (1.8 µl/min at 12 mmHg; 4.3 µl/min at 16 mmHg; 7.6 µl/min at 21 mmHg. X-ray diffraction analysis did not show oxidization of the ferrofluid when exposed to water or air. Preliminary in vivo results suggest that the valve is biocompatible and can control the intraocular pressure in rabbits. CONCLUSIONS: The proposed valve utilizes ferrofluid as passive, tunable constriction element to provide highly predictable opening and closing pressures while maintaining ocular tone. The ferrofluid maintained its magnetic properties in the aqueous environment and provided linear flow to pressure response. Our in-vitro tests showed reliable and reproducible results over a study period of three months. Preliminary in-vivo results were very promising and currently more thorough investigation of this device is underway.

  15. Transcatheter Aortic Valve Replacement: A Review Article

    Directory of Open Access Journals (Sweden)

    Juan A Siordia

    2016-06-01

    Full Text Available Transcatheter aortic valve replacement (TAVR is a novel therapeutic intervention for the replacement of severely stenotic aortic valves in high-risk patients for standard surgical procedures. Since the initial PARTNER trial results, use of TAVR has been on the rise each year. New delivery methods and different valves have been developed and modified in order to promote the minimally invasive procedure and reduce common complications, such as stroke. This review article focuses on the current data on the indications, risks, benefits, and future directions of TAVR. Recently, TAVR has been considered as a standard-of-care procedure. While this technique is used frequently in high-risk surgical candidates, studies have been focusing on the application of this method for younger patients with lower surgical risk. Moreover, several studies have proposed promising results regarding the use of valve-in-valve technique or the procedure in which the valve is placed within a previously implemented bioprosthetic valve. However, ischemic strokes and paravalvular leak remain a matter of debate in these surgeries. New methods and devices have been developed to reduce the incidence of post-procedural stroke. While the third generation of TAVR valves (i.e., Edwards Sapien 3 and Medtronic Evolut R addresses the issue of paravalvular leak structurally, results on their efficacy in reducing the risk of paravalvular leak are yet to be obtained. Furthermore, TAVR enters the field of hybrid methods in the treatment of cardiac issues via both surgical and catheter-based approaches. Finally, while TAVR is primarily performed on cases with aortic stenosis, new valves and methods have been proposed regarding the application of this technique in aortic regurgitation, as well as other aortic pathologies. TAVR is a suitable therapeutic approach for the treatment of aortic stenosis in high-risk patients. Considering the promising results in the current patient population

  16. Film edge nonlocal spin valves.

    Science.gov (United States)

    McCallum, Andrew T; Johnson, Mark

    2009-06-01

    Spintronics is a new paradigm for integrated digital electronics. Recently established as a niche for nonvolatile magnetic random access memory (MRAM), it offers new functionality while demonstrating low-power and high-speed performance. However, to reach high density spintronic technology must make a transition to the nanometer scale. Prototype devices are presently made using a planar geometry and have an area determined by the lithographic feature size, currently about 100 nm. Here we present a new nonplanar geometry in which one lateral dimension is given by a film thickness, on the order of 10 nm. With this new approach, cell sizes can shrink by an order of magnitude. The geometry is demonstrated with a nonlocal spin valve, where we study devices with an injector/detector separation much less than the spin diffusion length.

  17. Rotary Valve FY 2016 Highlights

    Energy Technology Data Exchange (ETDEWEB)

    Fitsos, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-12-07

    The fiscal year started with the Rotary Valve (RV) being reassembled after having crashed in June of 2015. The crash occurred when the RV inner surface contacted the housing. The cause of the crash was never confirmed. No particles were found in the 2.5 thousandths of an inch gap and the filters the helium gas passed through were all clean. There were marks on the bearings that looked like electrostatic discharge as shown below in Figure 1. These marks hadn’t been seen before and there were similar discharge marks on some of the ball bearings. Examples of this were found in a literature search of bearing failures. This leads to a possible cause due to this arcing affecting the rotational accuracy of the bearings driving the RV into the housing.

  18. Valve Corporation: Composing Internal Markets

    Directory of Open Access Journals (Sweden)

    Todd R. Zenger

    2015-07-01

    Full Text Available Discussions of the Valve Corporation are always enlightening. The skeptic wonders how much is rhetoric and recruiting ploy and how much is real. Is there clear evidence that this organizational design actually works – that it is efficient in this setting? While revenues per employee are quite remarkable, cause and effect are unclear. Is “boss-less-ness” the cause of high sales per employee or simply the result of high sales per employee, fueled from earlier success? The same question could be asked of Google’s unusual organizational approach. Is Google’s success the result of its extensive autonomy granted to employees, or is its past success the enabling cause of such autonomy? Such questions, of course, are empirically unanswerable here. I therefore set them aside and assume this organizational specimen is efficient – well-suited to its environment – and proceed with further commentary.

  19. Computed Flow Through An Artificial Heart Valve

    Science.gov (United States)

    Rogers, Stewart E.; Kwak, Dochan; Kiris, Cetin; Chang, I-Dee

    1994-01-01

    Report discusses computations of blood flow through prosthetic tilting disk valve. Computational procedure developed in simulation used to design better artificial hearts and valves by reducing or eliminating following adverse flow characteristics: large pressure losses, which prevent hearts from working efficiently; separated and secondary flows, which causes clotting; and high turbulent shear stresses, which damages red blood cells. Report reiterates and expands upon part of NASA technical memorandum "Computed Flow Through an Artificial Heart and Valve" (ARC-12983). Also based partly on research described in "Numerical Simulation of Flow Through an Artificial Heart" (ARC-12478).

  20. Bacillus cereus endocarditis in native aortic valve.

    Science.gov (United States)

    Ngow, H A; Wan Khairina, W M N

    2013-02-01

    Bacillus cereus endocarditis is rare. It has been implicated in immunocompromised individuals, especially in intravenous drug users as well as in those with a cardiac prosthesis. The patient was a 31-year-old ex-intravenous drug addict with a past history of staphylococcal pulmonary valve endocarditis, who presented with symptoms of decompensated cardiac failure. Echocardiography showed severe aortic regurgitation with an oscillating vegetation seen on the right coronary cusp of the aortic valve. The blood cultures grew Bacillus cereus. We report this as a rare case of Bacillus cereus endocarditis affecting a native aortic valve.

  1. Infective endocarditis following transcatheter aortic valve replacement-

    DEFF Research Database (Denmark)

    Loh, Poay Huan; Bundgaard, Henning; S�ndergaard, Lars

    2013-01-01

    Transcatheter aortic valve replacement (TAVR) can improve the symptoms and prognosis of patients with severe aortic stenosis who, due to a high expected operative risk, would not have otherwise been treated surgically. If these patients develop prosthetic valve endocarditis, their presentations may...... be atypical causing a delay in the diagnosis and treatment. The management is also complicated by their comorbidities, and surgical treatment may not be feasible leading to a significant morbidity and mortality. We describe a case of an 85-year-old man with TAVI prosthetic valve endocarditis successfully...

  2. The echocardiography of replacement heart valves

    Science.gov (United States)

    2016-01-01

    This is a practical description of how replacement valves are assessed using echocardiography. Normal transthoracic appearances including normal variants are described. The problem of differentiating normal function, patient–prosthesis mismatch and pathological obstruction in aortic replacement valves with high gradients is discussed. Obstruction and abnormal regurgitation is described for valves in the aortic, mitral and right-sided positions and when to use echocardiography in suspected infective endocarditis. The roles of transoesophageal and stress echocardiography are described and finally when other imaging techniques may be useful. PMID:27600454

  3. Combined pressure regulator and shutoff valve

    Science.gov (United States)

    Koch, E. F. (Inventor)

    1974-01-01

    A remotely operable pressure regulator and shutoff valve particularly suited for achieving high resolution and flow control, and positive shutoff is described. The valve is characterized by a spring-loaded ball coaxially aligned with a fluid port to be sealed, a spring-loaded pintle extended through the port into engagement with the ball, for controlling the position, a spring-loaded diaphragm for controlling the position of the pintle, and an axially displaceable spring supported by a movable stop which, in turn, is repositioned by a selectively operable stepper motor. Thus, the pressure-response characteristics for the valve can be varied through a selective repositioning of the stop.

  4. [New aspects in aortic valve disease].

    Science.gov (United States)

    Tornos, P

    2001-01-01

    Renewed interest for aortic valve disease has evolved in recent years. Aortic valve replacement has become the second most frequent cause of cardiac surgery, following coronary bypass surgery. In addition, the etiologic and physiopathologic knowledge of this disorder has improved. In the present paper we analyze three aspects of the disease which are, at present, the subject of study and controversy: first, we discuss the possible relationship between degenerative aortic stenosis and atherosclerosis; second, the involvement of the aortic root in cases of bicuspid aortic valve; and third, the surgical indications in asymptomatic patients with either aortic stenosis or regurgitation.

  5. Three-dimensional echocardiography in valve disease.

    Science.gov (United States)

    Colombo, Chiara; Tamborini, Gloria; Pepi, Mauro; Alimento, Marina; Fiorentini, Cesare

    2007-01-01

    This review covers the role of three-dimensional (3D) echocardiography in the diagnosis of heart valve disease. Several factors have contributed to the evolution of this technique, which is currently a simple and routine method: rapid evolution in probe and computer technologies, demonstration that 3D data sets allowed more complete and accurate evaluation of cardiac structures, emerging clinical experience indicating the strong potential particularly in valve diseases, volume and function of the two ventricle measurements and several other fields. This report will review current and future applications of 3D echocardiography in mitral, aortic and tricuspid valve diseases underlying both qualitative (morphologic) and quantitative advantages of this technique.

  6. Analysis of Writing Strategies of Vamp Image in Jude the Obscure%析《无名的裘德》中妖妇形象的书写策略

    Institute of Scientific and Technical Information of China (English)

    李金梅

    2011-01-01

    托马斯·哈代《无名的裘德》中的女性艾拉白拉一直被视为妖妇的代表。但是妖妇形象一直是男性话语世界对女性的一种丑化与诋毁的手段。本文具体分析哈代对艾拉白拉妖妇形象的三种书写策略:动物隐喻化、虚假行为的揭示和文学传统妖妇形象的借用,从而探索作者男权叙述视角下对妖妇型女性的丑化策略。%Arabella, a female character in Thomas Hardy's Jude the Obscure, has always been considered as a vamp representative. However, the writing of vamp image has been a means to smear and slander women in male discourses. This essay focuses on analyzing Hardy's three writing strategies on Arabella's image that are metaphor of animals, revelation of false action, and analogy of traditional vamp image Delilah to explore Hardy's tactics of smearing woman image from male narrative perspective.

  7. Fluid-Structure Interaction Analysis of Papillary Muscle Forces Using a Comprehensive Mitral Valve Model with 3D Chordal Structure.

    Science.gov (United States)

    Toma, Milan; Jensen, Morten Ø; Einstein, Daniel R; Yoganathan, Ajit P; Cochran, Richard P; Kunzelman, Karyn S

    2016-04-01

    Numerical models of native heart valves are being used to study valve biomechanics to aid design and development of repair procedures and replacement devices. These models have evolved from simple two-dimensional approximations to complex three-dimensional, fully coupled fluid-structure interaction (FSI) systems. Such simulations are useful for predicting the mechanical and hemodynamic loading on implanted valve devices. A current challenge for improving the accuracy of these predictions is choosing and implementing modeling boundary conditions. In order to address this challenge, we are utilizing an advanced in vitro system to validate FSI conditions for the mitral valve system. Explanted ovine mitral valves were mounted in an in vitro setup, and structural data for the mitral valve was acquired with [Formula: see text]CT. Experimental data from the in vitro ovine mitral valve system were used to validate the computational model. As the valve closes, the hemodynamic data, high speed leaflet dynamics, and force vectors from the in vitro system were compared to the results of the FSI simulation computational model. The total force of 2.6 N per papillary muscle is matched by the computational model. In vitro and in vivo force measurements enable validating and adjusting material parameters to improve the accuracy of computational models. The simulations can then be used to answer questions that are otherwise not possible to investigate experimentally. This work is important to maximize the validity of computational models of not just the mitral valve, but any biomechanical aspect using computational simulation in designing medical devices.

  8. Severe Bioprosthetic Mitral Valve Stenosis and Heart Failure in a Young Woman with Systemic Lupus Erythematosus

    Directory of Open Access Journals (Sweden)

    Siddharth Wartak

    2016-01-01

    Full Text Available A 23-year-old African American woman with a past medical history of systemic lupus erythematous (SLE, secondary hypertension, and end stage renal disease (ESRD on hemodialysis for eight years was stable until she developed symptomatic severe mitral regurgitation with preserved ejection fraction. She underwent a bioprosthetic mitral valve replacement (MVR at outside hospital. However, within a year of her surgery, she presented to our hospital with NYHA class IV symptoms. She was treated for heart failure but in view of her persistent symptoms and low EF was considered for heart and kidney transplant. This was a challenge in view of her history of lupus. We presumed that her stenosis of bioprosthetic valve was secondary to lupus and renal disease. We hypothesized that her low ejection fraction was secondary to mitral stenosis and potentially reversible. We performed a dobutamine stress echocardiogram, which revealed an improved ejection fraction to more than 50% and confirmed preserved inotropic contractile reserve of her myocardium. Based on this finding, she underwent a metallic mitral valve and tricuspid valve replacement. Following surgery, her symptoms completely resolved. This case highlights the pathophysiology of lupus causing stenosis of prosthetic valves and low ejection cardiomyopathy.

  9. Method and apparatus for monitoring motor operated valve motor output torque and power at valve seating

    Science.gov (United States)

    Casada, Donald A.

    1996-01-01

    A method and apparatus are provided for monitoring a motor operated valve during the brief period when the valve seats and the torque switch trips to deenergize the valve motor. The method uses voltage measurements on the load side of a deenergizing switch that opens to deenergize the motor to determine, among other things, final motor rotational speed and the decelerating torque at motor deenergization.

  10. Computational Fluid Dynamics Analysis of Butterfly Valve Performance Factors

    OpenAIRE

    Del Toro, Adam

    2012-01-01

    Butterfly valves are commonly used in industrial applications to control the internal flow of both compressible and incompressible fluids. A butterfly valve typically consists of a metal disc formed around a central shaft, which acts as its axis of rotation. As the valve's opening angle is increased from 0 degrees (fully closed) to 90 degrees (fully open), fluid is able to more readily flow past the valve. Characterizing a valve's performance factors, such as pressure drop, hydrodynamic torqu...

  11. Valve selection handbook engineering fundamentals for selecting the right valve design for every industrial flow application

    CERN Document Server

    Smith, Peter

    2004-01-01

    Valves are the components in a fluid flow or pressure system that regulate either the flow or the pressure of the fluid. They are used extensively in the process industries, especially petrochemical. Though there are only four basic types of valves, there is an enormous number of different kinds of valves within each category, each one used for a specific purpose. No other book on the market analyzes the use, construction, and selection of valves in such a comprehensive manner.-Covers new environmentally-conscious equipment and practices, the most important hot-button issue in the p

  12. Artificial SMA valve for treatment of urinary incontinence: upgrading of valve and introduction of transcutaneous transformer.

    Science.gov (United States)

    Tanaka, M; Hirano, K; Goto, H; Namima, T; Uchi, K; Jiang, Z W; Matsuki, H; Tanahashi, Y; Orikasa, S; Chonan, S

    1999-01-01

    This paper is concerned with the development of an artificial urethral valve driven by shape memory alloy actuators, which is attached onto the urethra of a urinary incontinence sufferer for treating the involuntary micturition. Three types of compact cylindrical valves are assembled and their opening and closing functions are examined experimentally. The updated valve is heated and opened by using the transcutaneous energy transformer consisting of a pair of flexible spiral-formed copper wire coils. The experiment using the canine urinary canal verifies that the total system of the valve and the transformer works well as an artificial sphictor muscle and controls the urinary flow through the canal appropriately.

  13. [Emergent transcatheter aortic valve implantation in a patient with bicuspid aortic valve stenosis in cardiogenic shock].

    Science.gov (United States)

    Pizzighini, S; Finet, G; Obadia, J-F; Revel, D; Bresson, D; Rioufol, G

    2015-02-01

    Transcatheter aortic valve implantation is a therapeutic option for high-risk patients with severe aortic valve stenosis and with cardiac symptoms. This procedure requires the preliminary evaluation by a "heart team" and presents some contraindications. We report the case of a 58-year-old man with severe bicuspid aortic valve stenosis and cardiogenic shock. In spite of contraindications and because of the failure of balloon aortic valvuloplasty, transcatheter aortic valve implantation was performed in emergency. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  14. In vitro evaluation of the iValve: a novel hands-free speech valve.

    Science.gov (United States)

    van der Houwen, Eduard B; van Kalkeren, Tjouwke A; Burgerhof, Johannes G M; van der Laan, Bernard F A M; Verkerke, Gijsbertus J

    2011-12-01

    We performed in vitro evaluation of a novel, disposable, automatic hands-free tracheostoma speech valve for laryngectomy patients based upon the principle of inhalation. The commercially available automatic speech valves close upon strong exhalation and open again when the pressure drops. This method makes long sentences or pauses difficult. The novel iValve is designed to allow almost natural speech, with mid-sentence pausing and whispering. The inhalation closing flows and exhalation opening pressures of 6 iValve prototype versions at different settings were compared with physiological values. The airflow resistance at inhalation was compared to physiological values and to commercial valve values. The iValve prototypes showed flow and pressure ranges in concordance with the physiological values in the literature. The airflow resistance in the breathing mode was within the physiological airflow resistance range, yet above the values from the two commercial valves. The resistance in the speaking mode was above the physiological airflow resistance range. In vitro tests show that the iValve versions can be selected and adjusted to operate within the physiological range. The airflow resistance in the breathing mode is good. In speaking mode, inhalation should, and can, be decreased. The iValve should offer the patient a more intuitively useable alternative with more dynamic speech. Its low cost allows disposability and wider use.

  15. Experimental study on wear failure course of gas-valve/valve-seat in engine

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yun-cai; YAN Hang-zhi

    2005-01-01

    The wear failure course of gas-valve/valve-seat in engine was investigated with a simulating tester. The results show that the failure of the contact conical surface is mainly caused by the elastic and plastic deformation and the fatigue micro-crack and spalling. The creep-deformation and corrosion atmosphere accelerated wear failure course at the high temperature. The wear failure course of the gas-valve/valve-seat in engine follows general wear rules of mechanical elements, but the rate of wear in the sharp wear stage is faster.

  16. Recellularization of decellularized heart valves: Progress toward the tissue-engineered heart valve

    Science.gov (United States)

    VeDepo, Mitchell C; Detamore, Michael S; Hopkins, Richard A; Converse, Gabriel L

    2017-01-01

    The tissue-engineered heart valve portends a new era in the field of valve replacement. Decellularized heart valves are of great interest as a scaffold for the tissue-engineered heart valve due to their naturally bioactive composition, clinical relevance as a stand-alone implant, and partial recellularization in vivo. However, a significant challenge remains in realizing the tissue-engineered heart valve: assuring consistent recellularization of the entire valve leaflets by phenotypically appropriate cells. Many creative strategies have pursued complete biological valve recellularization; however, identifying the optimal recellularization method, including in situ or in vitro recellularization and chemical and/or mechanical conditioning, has proven difficult. Furthermore, while many studies have focused on individual parameters for increasing valve interstitial recellularization, a general understanding of the interacting dynamics is likely necessary to achieve success. Therefore, the purpose of this review is to explore and compare the various processing strategies used for the decellularization and subsequent recellularization of tissue-engineered heart valves. PMID:28890780

  17. Mitral Valve Replacement with a Mechanical Valve for Severe Mitral Regurgitation in a Small Dog

    Directory of Open Access Journals (Sweden)

    Daisuke Taguchi

    2014-01-01

    Full Text Available A seven-year-old Shih Tzu with refractory repeated pulmonary edema and syncope was presented for surgical operation. From the results of cardiovascular examinations, the dog was diagnosed as severe mitral regurgitation (ACVIM consensus class D and mild tricuspid regurgitation. The dog first underwent surgery with mitral valve plasty; however, the results were unsatisfactory due to severe damage of the whole mitral valve. The operation was quickly changed to mitral valve replacement using a mechanical valve (19 mm. The dog survived surgery and lived for 2 years and one month after operation using long-term anticoagulant (warfarin therapy in spite of several thrombosis-related events.

  18. Basis of valve operator selection for SMART

    Energy Technology Data Exchange (ETDEWEB)

    Kang, H. S.; Lee, D. J.; See, J. K.; Park, C. K.; Choi, B. S

    2000-05-01

    SMART, an integral reactor with enhanced safety and operability, is under development for use of the nuclear energy. The valve operator of SMART system were selected through the data survey and technical review of potential valve fabrication vendors, and it will provide the establishment and optimization of the basic system design of SMART. In order to establish and optimize the basic system design of SMART, the basis of selection for the valve operator type were provided based on the basic design requirements. The basis of valve operator selection for SMART will be used as a basic technical data for the SMART basic and detail design and a fundamental material for the new reactor development in the future.

  19. Valve Technology Arrangement of Cryopump: A Review

    Directory of Open Access Journals (Sweden)

    Sanjiv Y. Rajput

    2014-05-01

    Full Text Available A cryopump or a "cryogenic pump" is a vacuum pump that pumps the trap gases and vapours by condensing them on a cold surface. Helium gas which is very light can only be pumped by Cryopump. Cryopump cannot be used when working for continuous operation as it pumps the effluent till the saturation state is achieved. Then the absorbed gases are to be collected through other mechanical pump through regeneration process. Hence, valve technology arrangement is incorporated with the cryopump in order to achieve the continuous pumping when two cryopump are used in alternate processes (i.e. absorption and regeneration. Various design of Valve technology arrangement is proposed by different researcher all over the world. This review paper focuses on the different proposed valve technology arrangement and elaborately explains the various components of valve technology and concludes the best possible arrangement that can be used in Cryopump.

  20. Heritable retinoblastoma and accelerated aortic valve disease

    Science.gov (United States)

    Abeyratne, L R; Kingston, J E; Onadim, Z; Dubrey, S W

    2013-01-01

    Heritable retinoblastoma is associated with a germline mutation in the tumour suppressor gene RBI. The Rb protein (pRb) arises from the RB1 gene, which was the first demonstrated cancer susceptibility gene in humans. 1 Second primary malignancies are recognised complications of retinoblastoma. Furthermore, pRb is implicated in valve remodelling in calcific aortic valve disease. 2 3 We report a family with hereditary retinoblastoma and associated secondary primary malignancies. There are two interesting aspects to this family. The first is the concept of ‘cancer susceptibility genes’; the RBI gene being the first reported in humans. A further feature of note is that two family members also have bicuspid aortic valves. We discuss a potential association between the gene defect responsible for retinoblastoma (with its associated propensity for further malignancies) and accelerated deterioration of the bicuspid aortic valve in the proband carrying this gene defect. PMID:23595191

  1. Simulation of a Hydraulic Pump Control Valve

    Science.gov (United States)

    Molen, G. Vander; Akers, A.

    1987-01-01

    This paper describes the mode of operation of a control valve assembly that is used with a hydraulic pump. The operating system of the valve is modelled in a simplified form, and an analogy for hydraulic resonance of the pressure sensing system is presented. For the control valve investigated, air entrainment, length and diameter of the resonator neck, and valve mass produced the greatest shift in resonant frequency. Experimental work was conducted on the hydraulic system so that the resonance levels and frequencies could be measured and the accuracy of the theory verified. The results obtained make it possible to evaluate what changes to any of the variables considered would be most effective in driving the second harmonic frequency above the operating range.

  2. Minimally Invasive Transcatheter Aortic Valve Replacement (TAVR)

    Medline Plus

    Full Text Available Watch a Broward Health surgeon perform a minimally invasive Transcatheter Aortic Valve Replacement (TAVR) Click Here to view the BroadcastMed, Inc. Privacy Policy and Legal Notice © 2017 BroadcastMed, Inc. ...

  3. VOST Flow-Control Valve Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A cryogenic flow-control valve based on Venturi-Offset Technology (VOST) will be designed and modeled. VOST provides precise linear flow control within a...

  4. Low-Mass VOST Valve Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A cylindrical, low-mass, high-efficiency, leak-proof cryogenic valve will be designed using composites and exotic metals. Based upon cryogenically-proven Venturi...

  5. VOST Flow-Control Valve Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Two cryogenic flow-control valves of diameters 1/2" and 2" will be built and tested. Based on cryogenically-proven Venturi Off-Set Technology (VOST) they have no...

  6. Glovebox pressure relief and check valve

    Energy Technology Data Exchange (ETDEWEB)

    Blaedel, K.L.

    1986-03-17

    This device is a combined pressure relief valve and check valve providing overpressure protection and preventing back flow into an inert atmosphere enclosure. The pressure relief is embodied by a submerged vent line in a mercury reservior, the releif pressure being a function of the submerged depth. The pressure relief can be vented into an exhaust system and the relieving pressure is only slightly influenced by the varying pressure in the exhaust system. The check valve is embodied by a ball which floats on the mercury column and contacts a seat whenever vacuum exists within the glovebox enclosure. Alternatively, the check valve is embodied by a vertical column of mercury, the maximum back pressure being a function of the height of the column of mercury.

  7. Contamination avoidance devices for poppettype shutoff valves

    Science.gov (United States)

    Endicott, D. L.

    1973-01-01

    The determination of the cycle life is reported of the scal closure of a typical poppet-type shutoff valve in an uncontaminated GH2 environment and then compared this component performance with simulated operation with GN2 and LN2 containing controlled amounts of AL2O3 contaminant particles. The original valve design was tested for contamination damage tolerance characteristics under full-flow and cyclic-operating conditions, redesigned to improve the damage tolerance to contaminants, and then retested. The redesigned valve was found to have acceptable tolerance characteristics under all full-flow conditions and cyclic operation with small (25-75 microns) particulate contamination. The tolerance characteristics of the valve under cyclic conditions with large (75-250 microns) particulate contamination was improved but was not found to be completely satisfactory.

  8. Surgical Treatment of Congenital Mitral Valve Dysplasia.

    Science.gov (United States)

    Vida, Vladimiro L; Carrozzini, Massimiliano; Padalino, Massimo; Milanesi, Ornella; Stellin, Giovanni

    2016-05-01

    Congenital mitral valve (MV) dysplasia is a relatively rare and highly complex cardiac disease. We present our results and illustrate the techniques used to repair these valves. Between 1972 and 2014, 100 consecutive patients underwent surgical repair of congenital MV dysplasia at our institution. Predominant MV regurgitation was present in 53 patients (53%) whereas mitral stenosis was prevalent in 47 (47%). There were five early (5%) and eight late deaths (9%). Actuarial survival was 95%, 94%, and 93% at 5, 10, and 20 years, respectively. Sixteen patients (18%) required reintervention due to subsequent MV dysfunction. Actuarial freedom from reintervention for MV dysfunction was 95%, 92%, and 89% at 5, 10, and 20 years, respectively. The mechanism underlying the valve dysfunction in congenital mitral valve dysplasia is multifactorial and requires the application of a variety of surgical techniques for repair. doi: 10.1111/jocs.12743 (J Card Surg 2016;31:352-356). © 2016 Wiley Periodicals, Inc.

  9. Electrodynamic actuators for rocket engine valves

    Science.gov (United States)

    Fiet, O.; Doshi, D.

    1972-01-01

    Actuators, employed in acoustic loudspeakers, operate liquid rocket engine valves by replacing light paper cones with flexible metal diaphragms. Comparative analysis indicates better response time than solenoid actuators, and improved service life and reliability.

  10. High Reliability Cryogenic Piezoelectric Valve Actuator Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Piezoelectric actuators constructed with the "smart material" PZT offer many potential advantages for use in NASA cryo-valve missions relative to conventional...

  11. Percutaneous Valvuloplasty for Bioprosthetic Tricuspid Valve Stenosis

    Science.gov (United States)

    Malhotra, Rohit; Sharma, Anjali; Kakouros, Nikolaos

    2017-01-01

    Percutaneous transcatheter tricuspid balloon valvuloplasty (PTTBV) is an accepted treatment option for symptomatic severe native tricuspid valve stenosis, although surgical tricuspid valve replacement remains the treatment of choice. There have been few reports of successful PTTBV for bioprosthetic tricuspid valve stenosis. We present case reports of 3 patients from our hospital experience. Two of the 3 cases were successful, with lasting clinical improvement, whereas the 3rd patient failed to show a reduction in valve gradient. We describe the standard technique used for PTTBV. We present results from a literature review that identified 16 previously reported cases of PTTBV for bioprosthetic severe tricuspid stenosis, with overall favorable results. We conclude that PTTBV should perhaps be considered for a select patient population in which symptomatic improvement and hemodynamic stability are desired immediately, and particularly for patients who are inoperable or at high surgical risk.

  12. Minimally Invasive Transcatheter Aortic Valve Replacement (TAVR)

    Medline Plus

    Full Text Available Watch a Broward Health surgeon perform a minimally invasive Transcatheter Aortic Valve Replacement (TAVR) Click Here to view the BroadcastMed, Inc. Privacy Policy and Legal Notice © 2017 BroadcastMed, Inc. ...

  13. Computed Tomography of Prosthetic Heart Valves

    NARCIS (Netherlands)

    Habets, J.

    2012-01-01

    Prosthetic heart valve (PHV) dysfunction is an infrequent but potentially life-threatening disease with a heterogeneous clinical presentation. Patients with PHV dysfunction clinically can present with symptoms of congestive heart failure (dyspnea, fatigue, edema), fever, angina pectoris, dizziness d

  14. Low-Mass VOST Valve Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Two low-mass, linear throttling, high-efficiency, leak-proof cryogenic valves of diameters 1/2" and 4" will be built and tested. Based upon cryogenically-proven...

  15. Transcatheter Aortic Valve Replacement in a Patient With a Previous Bioprosthetic Mitral Valve Replacement: Report of a Delayed Fatal Interaction.

    Science.gov (United States)

    Poulin, Frédéric; Lamarche, Yoan; Le, Van Hoai Viet; Doucet, Michel; Roméo, Philippe; Généreux, Philippe

    2016-02-01

    We report on a man with bioprosthetic mitral valve perforation who presented late after transcatheter aortic valve replacement with a balloon-expandable transcatheter heart valve (THV). The protrusion of the commissural strut of the bioprosthetic mitral valve coupled with the low implanted THV resulted in repetitive trauma leading to rupture of a mitral leaflet. Potential preventive strategies are discussed. This case illustrates the importance of preprocedural imaging screening and cautious THV deployment in patients with a bioprosthetic mitral valve.

  16. Tenecteplase in prosthetic mitral valve thrombosis

    OpenAIRE

    2010-01-01

    In the few reported cases of prosthetic mitral valve thrombosis, where surgical intervention was considered as high risk, fibrinolytic therapy had proved life saving. The authors present clinical, laboratory, and imaging data from such a patient, with prosthetic mitral valve thrombosis and its successful management with tenecteplase. The use of tenecteplase as a viable fibrinolytic agent for the first time was justified, due to the lack of immunogenicity concerns compared to streptokinase.

  17. Tenecteplase in prosthetic mitral valve thrombosis.

    Science.gov (United States)

    Ayyub Ghori, Masood; Bakir, Sherif; Ellahham, Samer; Al Nassir, Adnan; Al Zubaidi, Abdulmajeed; Augustin, Norbert; Abdelaziz, Moataz Ayman; Turrin, Nicolas Patrick; Al Mahmeed, Wael Abdulrahman

    2011-04-01

    In the few reported cases of prosthetic mitral valve thrombosis, where surgical intervention was considered as high risk, fibrinolytic therapy had proved life saving. The authors present clinical, laboratory, and imaging data from such a patient, with prosthetic mitral valve thrombosis and its successful management with tenecteplase. The use of tenecteplase as a viable fibrinolytic agent for the first time was justified, due to the lack of immunogenicity concerns compared to streptokinase.

  18. Symptomatic papillary tumour of the pulmonary valve

    OpenAIRE

    Cooper, Linda Carol

    1982-01-01

    Papillary ‘tumours’ are small pedunculated lesions of the valve cusps and result from wear-and-tear. They are therefore frequent post-mortem findings in older patients. The vast majority are clinically silent, though occasionally such lesions when on the aortic valve may produce symptoms of myocardial or cerebral ischaemia. None has been known to cause symptoms when in the right side of the heart.

  19. Reconstructive surgery of the aortic valve

    Directory of Open Access Journals (Sweden)

    Mendonça José Teles de

    2003-01-01

    Full Text Available OBJECTIVE: Lacking an ideal valve substitute and motivated by the good results of mitral valve repair since 1990, we faced with determination aortic valve reconstruction surgery. The objective of this paper is to show our experience with this procedure. METHOD: Between January of 1990 and December of 2001; 136 aortic valve repair surgeries were performed. Seventy-five (55.1% of the patients were female and the ages ranged from 4 to 70 years (mean 23.3 ± 1.2 years. Every patient had rheumatic valve disease and insufficiency was the most prevalent type (108 patients - 79.4%, followed by double aortic lesion in 16 (11.7% patients and stenosis in 12 (8.8%. The surgical techniques used were: subcommissural annuloplasty in 74 (54.4% patients, commissurotomy in 38 (27.9%, cusp extension with pericardium in 17 (12.5%, substitution of one cusp in 2 (1.4%, cusp suspension by annuloplasty in 37 (27.2% and Valsalva sinus remodeling in 27 (19.8%. The surgery exclusively involved the aortic valve in 57 (41.9% patients and was associated in 79 (mitral valve replacement in 12, mitral repair in 65, coronary artery bypass grafting in 1 and pulmonary commissurotomy in 1. RESULTS: Hospital mortality was 2.2% and 22 (16.2% patients underwent a new surgery during the follow-up period (57.7 ± 3.5 months. CONCLUSIONS: Aortic valve repair is a safe surgical procedure that can be used in an increasing number of patients with promising results.

  20. DIAGNOSTICS AND TREATMENT OF MITRAL VALVE PROLAPSE

    Directory of Open Access Journals (Sweden)

    D. A. Kuzhel

    2010-01-01

    Full Text Available The mitral valve prolapse (MVP is one of the most inconsistent diagnose. In the most cases patients with MVP have the good long-term prognosis, and therapy is aimed at reduction in psychovegetative dysfunction. Careful follow-up and timely cardiosurgical correction should be performed, if necessary, in patients with classical MPV. The choice method in these cases is the mitral valve plasty.

  1. Refuge alternatives relief valve testing and design.

    Science.gov (United States)

    Lutz, T J; Bissert, P T; Homce, G T; Yonkey, J A

    2016-10-01

    The U.S. National Institute for Occupational Safety and Health (NIOSH) has been researching refuge alternatives (RAs) since 2007. RAs typically have built-in pressure relief valves (PRVs) to prevent the unit from reaching unsafe pressures. The U.S. Mine Safety and Health Administration requires that these valves vent the chamber at a maximum pressure of 1.25 kPa (0.18 psi, 5.0 in. H2O), or as specified by the manufacturer, above mine atmospheric pressure in the RA. To facilitate PRV testing, an instrumented benchtop test fixture was developed using an off-the-shelf centrifugal blower and ductwork. Relief pressures and flow characteristics were measured for three units: (1) a modified polyvinyl chloride check valve, (2) an off-the-shelf brass/cast-iron butterfly check valve and (3) a commercially available valve that was designed specifically for one manufacturer's steel prefabricated RAs and had been adapted for use in one mine operator's built-in-place RA. PRVs used in tent-style RAs were not investigated. The units were tested with different modifications and configurations in order to check compliance with Title 30 Code of Federal Regulations, or 30 CFR, regulations. The commercially available relief valve did not meet the 30 CFR relief pressure specification but may meet the manufacturer's specification. Alternative valve designs were modified to meet the 30 CFR relief pressure specification, but all valve designs will need further design research to examine survivability in the event of a 103 kPa (15.0 psi) impulse overpressure during a disaster.

  2. Fibrinolytic therapy for mechanical pulmonary valve thrombosis.

    Science.gov (United States)

    Khajali, Zahra; Mohammadzadeh, Shabnam; Maleki, Majid; Peighambari, Mohammad Mehdi; Sadeghpoor, Anita; Ghavidel, Alireza; Elahi, Behrad; Mirzaaghayan, Mohammadreza

    2015-01-01

    Treatment of prosthetic heart valve thrombosis using intravenous thrombolytics, although an acceptable alternative to surgery, is not complication free, and the literature has a dearth of data on the subject. This study analyzed the results of fibrinolytic treatment (FT) among a single-center group of patients with mechanical pulmonary valve thrombosis. Between 2000 and 2013, 23 consecutive patients with 25 episodes of pulmonary valve thrombosis received FT. The diagnosis of mechanical pulmonary valve thrombosis was established by fluoroscopy and echocardiography. Streptokinase (SK) was used in 24 cases and alteplase in 1 case. The FT was continued a second day for 14 patients (58.3%), a third day for 1 patient, and a fourth day for 1 patient. Echocardiography and fluoroscopy were performed every day until improvement of malfunction was achieved. Of the 23 patients, 19 had complete resolution of hemodynamic abnormalities after FT, 1 had partial resolution, and 2 showed no change. No patient had major complications. Five minor complications were detected, namely, fever, nausea, thrombophlebitis, epistaxi, and pain. Seven patients (30%) experienced recurrence of thrombosis, whereas four patients had surgery (biological pulmonary valve replacement) without re-thrombolytic therapy, one patient was treated with Alteplase, one patient received SK, and one patient received intense anticoagulation using heparin and warfarin. Overall, FT had a success rate of 84%. The results indicate that regardless of the time to pulmonary valve replacement and echocardiographic and fluoroscopic findings, FT was effective in most cases of mechanical pulmonary valve thrombosis. The efficacy increased with second-day thrombolytic therapy. Major complications were not common after lytic therapy for mechanical pulmonary valve thrombosis.

  3. Native valve Escherichia coli endocarditis following urosepsis.

    Science.gov (United States)

    Rangarajan, D; Ramakrishnan, S; Patro, K C; Devaraj, S; Krishnamurthy, V; Kothari, Y; Satyaki, N

    2013-05-01

    Gram-negative organisms are a rare cause of infective endocarditis. Escherichia coli, the most common cause of urinary tract infection and gram-negative septicemia involves endocardium rarely. In this case report, we describe infection of native mitral valve by E. coli following septicemia of urinary tract origin in a diabetic male; subsequently, he required prosthetic tissue valve replacement indicated by persistent sepsis and congestive cardiac failure.

  4. Transcutaneous aortic valve replacement with the Edwards SAPIEN XT and Medtronic CoreValve prosthesis under fluoroscopic guidance and local anaesthesia only.

    Science.gov (United States)

    Greif, Martin; Lange, Philipp; Näbauer, Michael; Schwarz, Florian; Becker, Christoph; Schmitz, Christoph; Pohl, Tilmann; D'Anastasi, Melvin; Boekstegers, Peter; Massberg, Steffen; Kupatt, Christian

    2014-05-01

    To assess the feasibility of transcatheter aortic valve implantation (TAVI; Medtronic CoreValve and Edwards SAPIEN XT) under local anaesthesia with only mild analgesic medication and fluoroscopic guidance. 461 patients underwent TAVI under local anaesthesia with lidocaine. The procedure was performed successfully in 459 of the cases. All patients were also treated with piritramide, metoclopramide hydrochloride and 62 mg dimenhydrinate. Monitoring consisted of a six-electrode, virtual 12-lead ECG, pulse oximetry, and invasive arterial pressure measurement. There was no continuous surveillance by an anaesthesiologist. There was no need for conversion to general anaesthesia except in four patients who required cardiopulmonary resuscitation. Conscious sedation with intravenous administration of midazolam for agitation or inotropic medication for prolonged hypotension was necessary in only seven of the 461 patients. The combined safety end point according to the Valve Academic Research Consortium consensus document was reached in 12.6%. Our results show that TAVI performed under local anaesthesia with only mild analgesic medication and under fluoroscopic guidance is feasible, with good outcome comparable to published data.

  5. Europa Propulsion Valve Seat Material Testing

    Science.gov (United States)

    Addona, Brad M.

    2017-01-01

    The Europa mission and spacecraft design presented unique challenges for selection of valve seat materials that met the fluid compatibility requirements, and combined fluid compatibility and high radiation exposure level requirements. The Europa spacecraft pressurization system valves will be exposed to fully saturated propellant vapor for the duration of the mission. The effects of Nitrogen Tetroxide (NTO) and Monomethylhydrazine (MMH) propellant vapors on heritage valve seat materials, such as Vespel SP-1 and Polychlorotrifluoroethylene (PCTFE), were evaluated to determine if an alternate material is required. In liquid system applications, Teflon is the only available compatible valve seat material. Radiation exposure data for Teflon in an air or vacuum environment has been previously documented. Radiation exposure data for Teflon in an oxidizer environment such as NTO, was not available, and it was unknown whether the effects would be similar to those on air-exposed samples. Material testing was conducted by Marshall Space Flight Center (MSFC) and White Sands Test Facility (WSTF) to determine the effects of propellant vapor on heritage seat materials for pressurization valve applications, and the effects of combined radiation and NTO propellant exposure on Teflon. The results indicated that changes in heritage pressurization valve seat materials' properties rendered them unsuitable for the Europa application. The combined radiation and NTO exposure testing of Teflon produced results equivalent to combined radiation and air exposure results.

  6. 2D DIGITAL SIMPLIFIED FLOW VALVE

    Institute of Scientific and Technical Information of China (English)

    Ruan Jian; Li Sheng; Pei Xiang; Burton R; Ukrainetz P; Bitner D

    2004-01-01

    The 2D digital simplified flow valve is composed of a pilot-operated valve designed with both rotary and linear motions of a single spool,and a stepper motor under continual control.How the structural parameters affect the static and dynamic characteristics of the valve is first clarified and a criterion for stability is presented.Experiments are designed to test the performance of the valve.It is necessary to establish a balance between the static and dynamic characteristics in deciding the structural parameters.Nevertheless,it is possible to maintain the dynamic response at a fairly high level,while keeping the leakage of the pilot stage at an acceptable level.One of the features of the digital valve is stage control.In stage control the nonlinearities,such as electromagnetic saturation and hysteresis,are greatly reduced.To a large extent the dynamic response of the valve is decided by the executing cycle of the control algorithm.

  7. Pulmonary-Valve Replacement in Adults: Results With the Medtronic Freestyle Valve.

    Science.gov (United States)

    Ramanan, Sowmya; Doll, Nicolas; Boethig, Dietmar; Tafer, Nadir; Horke, Alexander; Roques, Xavier; Hemmer, Wolfgang Bruno; Roubertie, François

    2015-09-01

    We used the Medtronic Freestyle valve (Medtronic, Minneapolis, MN) as an orthotopic conduit in pulmonary valve replacement in repaired tetralogy of Fallot and as part of the Ross procedure. Midterm outcomes and hemodynamic status of this conduit were analyzed and performances in both subgroups were compared. From February 2002 to July 2012, 115 Freestyle valves were implanted in 52 patients with tetralogy of Fallot and 63 patients within the Ross procedure. Preoperative and perioperative data were reviewed retrospectively in this bicentric study. Mean age at valve surgery was 37 ± 13 years. Median implanted valve size was 27 mm (21 to 29). Early postoperative mortality was 3.48%. There was 100% follow-up for the survivors at a mean of 4.38 ± 2.52 years. There was 1 case of thromboembolism (0.89%), 6 endocarditis (5.4%), and 9 (7.8%) conduit re-interventions. Echocardiography at discharge and last follow-up showed average peak systolic transvalvular gradients of 12.4 ± 5.1 and 18.7 ± 8.8 mm Hg, respectively. Ten patients had significant proximal anastomotic gradients of greater than 50 mm Hg and 4 moderate conduit regurgitations. Survival was 96.52%. No valve degeneration was seen in 87.82% at 5 years. The only risk factor identified for valve re-intervention was conduit implantation without infundibular hood (p = 0.01 in multivariate analysis). Mid-term data show that Freestyle valves are well suited for pulmonary valve replacement in adults in both categories. The surgical technique used in valve implantation is important to ensure conduit durability. These results and accessibility to the Freestyle valve make this an acceptable alternative to homografts. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  8. Electromechanically Actuated Valve for Controlling Flow Rate

    Science.gov (United States)

    Patterson, Paul

    2007-01-01

    A proposed valve for controlling the rate of flow of a fluid would include an electric-motor-driven ball-screw mechanism for adjusting the seating element of the valve to any position between fully closed and fully open. The motor would be of a type that can be electronically controlled to rotate to a specified angular position and to rotate at a specified rate, and the ball screw would enable accurate linear positioning of the seating element as a function of angular position of the motor. Hence, the proposed valve would enable fine electronic control of the rate of flow and the rate of change of flow. The uniqueness of this valve lies in a high degree of integration of the actuation mechanism with the flow-control components into a single, relatively compact unit. A notable feature of this integration is that in addition to being a major part of the actuation mechanism, the ball screw would also be a flow-control component: the ball screw would be hollow so as to contain part of the main flow passage, and one end of the ball screw would be the main seating valve element. The relationships among the components of the valve are best understood by reference to the figure, which presents meridional cross sections of the valve in the fully closed and fully open positions. The motor would be supported by a bracket bolted to the valve body. By means of gears or pulleys and a timing belt, motor drive would be transmitted to a sleeve that would rotate on bearings in the valve body. A ball nut inside the sleeve would be made to rotate with the sleeve by use of a key. The ball screw would pass through and engage the ball nut. A key would prevent rotation of the ball screw in the valve body while allowing the ball screw to translate axially when driven by the ball nut. The outer surface of the ball screw would be threaded only in a mid-length region: the end regions of the outer surface of the ball screw would be polished so that they could act as dynamic sealing surfaces

  9. 28. Critical pulmonary valve stenosis: Medical management beyond balloon dilation

    Directory of Open Access Journals (Sweden)

    Muhammad Arif Khan

    2015-10-01

    Conclusion: Phentolamine and/or Captopril have a therapeutic role in neonates with critical PVS who remain oxygen dependent after balloon dilation. Both medicationslead to vasodilatation of pulmonary and systemic vascularity. They facilitate inflowto the right ventricle. Right to left shunt across a PFO or/ ASD minimizesand saturation improves leading to a significantreduction in length of hospitalization.

  10. Shape Memory Actuated Normally Open Permanent Isolation Valve

    Science.gov (United States)

    Ramspacher, Daniel J. (Inventor); Bacha, Caitlin E. (Inventor)

    2017-01-01

    A valve assembly for an in-space propulsion system includes an inlet tube, an outlet tube, a valve body coupling the inlet tube to the outlet tube and defining a propellant flow path, a valve stem assembly disposed within the valve body, an actuator body coupled to the valve body, the valve stem assembly extending from an interior of the valve body to an interior of the actuator body, and an actuator assembly disposed within the actuator body and coupled to the valve stem assembly, the actuator assembly including a shape memory actuator member that when heated to a transition temperature is configured to enable the valve stem assembly to engage the outlet tube and seal the propellant flow path.

  11. The prognosis of infective endocarditis treated with biological valves versus mechanical valves: A meta-analysis.

    Science.gov (United States)

    Tao, Ende; Wan, Li; Wang, WenJun; Luo, YunLong; Zeng, JinFu; Wu, Xia

    2017-01-01

    Surgery remains the primary form of treatment for infective endocarditis (IE). However, it is not clear what type of prosthetic valve provides a better prognosis. We conducted a meta-analysis to compare the prognosis of infective endocarditis treated with biological valves to cases treated with mechanical valves. Pubmed, Embase and Cochrane databases were searched from January 1960 to November 2016.Randomized controlled trials, retrospective cohorts and prospective studies comparing outcomes between biological valve and mechanical valve management for infective endocarditis were analyzed. The Newcastle-Ottawa Scale(NOS) was used to evaluate the quality of the literature and extracted data, and Stata 12.0 software was used for the meta-analysis. A total of 11 publications were included; 10,754 cases were selected, involving 6776 cases of biological valves and 3,978 cases of mechanical valves. The all-cause mortality risk of the biological valve group was higher than that of the mechanical valve group (HR = 1.22, 95% CI 1.03 to 1.44, P = 0.023), as was early mortality (RR = 1.21, 95% CI 1.02 to 1.43, P = 0.033). The recurrence of endocarditis (HR = 1.75, 95% CI 1.26 to 2.42, P = 0.001), as well as the risk of reoperation (HR = 1.79, 95% CI 1.15 to 2.80, P = 0.010) were more likely to occur in the biological valve group. The incidence of postoperative embolism was less in the biological valve group than in the mechanical valve group, but this difference was not statistically significant (RR = 0.90, 95% CI 0.76 to 1.07, P = 0.245). For patients with prosthetic valve endocarditis (PVE), there was no significant difference in survival rates between the biological valve group and the mechanical valve group (HR = 0.91, 95% CI 0.68 to 1.21, P = 0.520). The results of our meta-analysis suggest that mechanical valves can provide a significantly better prognosis in patients with infective endocarditis. There were significant differences in the clinical features of patients

  12. The Use of Stepper Motor-Controlled Proportional Valve for Fio2 Calculation in the Ventilator and its Control with Fuzzy Logic.

    Science.gov (United States)

    Gölcük, Adem; Güler, İnan

    2017-01-01

    This article proposes the employment of a proportional valve that can calculate the amount of oxygen in the air to be given to patient in accordance with the amount of FiO2 which is set from the control menu of the ventilation device. To actualize this, a stepper motor-controlled proportional valve was used. Two counts of valves were employed in order to control the gases with 2 bar pressure that came from both the oxygen and medical air tanks. Oxygen and medical air manometers alongside the pressure regulators were utilized to perform this task. It is a fuzzy-logic-based controller which calculates at what rate the proportional valves will be opened and closed for FiO2 calculation. Fluidity and pressure of air given by the ventilation device were tested with a FlowMeter while the oxygen level was tested using the electronic lung model. The obtained results from the study revealed that stepper motor controlled proportional valve could be safely used in ventilation devices. In this article, it was indicated that fluidity and pressure control could be carried out with just two counts of proportional valve, which could be done with many solenoid valves, so this reduces the cost of ventilator, electrical power consumed by the ventilator, and the dimension of ventilator.

  13. Transcatheter aortic valve implantation vs. surgical aortic valve replacement for treatment of severe aortic stenosis

    DEFF Research Database (Denmark)

    Siontis, George C M; Praz, Fabien; Pilgrim, Thomas

    2016-01-01

    AIMS: In view of the currently available evidence from randomized trials, we aimed to compare the collective safety and efficacy of transcatheter aortic valve implantation (TAVI) vs. surgical aortic valve replacement (SAVR) across the spectrum of risk and in important subgroups. METHODS AND RESULTS...

  14. Transcatheter Aortic Valve Replacement With Early- and New-Generation Devices in Bicuspid Aortic Valve Stenosis

    DEFF Research Database (Denmark)

    Yoon, Sung-Han; Lefèvre, Thierry; Ahn, Jung-Ming

    2016-01-01

    BACKGROUND: Few studies have evaluated the clinical outcomes of transcatheter aortic valve replacement (TAVR) in patients with bicuspid aortic valve stenosis (AS). Particularly, limited data exist comparing the results of TAVR with new-generation devices versus early-generation devices. OBJECTIVE...

  15. 40 CFR 60.483-1 - Alternative standards for valves-allowable percentage of valves leaking.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Alternative standards for valves-allowable percentage of valves leaking. 60.483-1 Section 60.483-1 Protection of Environment ENVIRONMENTAL... Before November 7, 2006 § 60.483-1 Alternative standards for valves—allowable percentage of...

  16. Single-centre experience with mitral valve repair in asymptomatic patients with severe mitral valve regurgitation

    NARCIS (Netherlands)

    W.J. van Leeuwen (Wouter); S.J. Head (Stuart); L.E. de Groot-de Laat (Lotte); M.L. Geleijnse (Marcel); A.J.J.C. Bogers (Ad); L.A. van Herwerden (Lex); A.P. Kappetein (Arie Pieter)

    2013-01-01

    textabstractOBJECTIVES: Guidelines recommend surgical mitral valve repair in selected patients with asymptomatic severe mitral valve regurgitation (MR), but the role of repair remains a matter of debate. Survival analyses of operated asymptomatic patients have been reported, but long-term haemodynam

  17. In Vitro Evaluation of the iValve : A Novel Hands-Free Speech Valve

    NARCIS (Netherlands)

    van der Houwen, E.B.; van Kalkeren, T.A.; Burgerhof, J.G.; van der Laan, B.F.; Verkerke, G.J.

    2011-01-01

    Objectives: We performed in vitro evaluation of a novel, disposable, automatic hands-free tracheostoma speech valve for laryngectomy patients based upon the principle of inhalation. The commercially available automatic speech valves close upon strong exhalation and open again when the pressure

  18. Replacing the valve restoring the flow: Effects of transcatheter aortic valve implantation

    NARCIS (Netherlands)

    Wiegerinck, E.M.A.

    2016-01-01

    When conventional surgery is not an option due to high surgical risk, transcatheter aortic valve implantation (TAVI) is a firmly established alternative and an effective and safe treatment option in this patient population. This thesis focuses on treatment of aortic valve stenosis by TAVI. The aim i

  19. Idiopathic mitral valve prolapse with tricuspid, aortic and pulmonary valve involvement: An autopsy case report

    Directory of Open Access Journals (Sweden)

    Heena M Desai

    2015-01-01

    Full Text Available Mitral valve prolapse (MVP is usually asymptomatic, but can be associated with complications such as infective endocarditis, mitral regurgitation, thromboembolism and sudden cardiac death. It has been very rarely reported to occur in association with other valvular involvement. A 55-year-old male patient was brought dead and at autopsy the mitral valve orifice was stenotic and the leaflets were enlarged, myxoid and bulging suggestive of MVP and chordae tendinae were thickened, stretched and elongated. Similar changes were seen in the tricuspid valve. The pulmonary and aortic valves also showed myxomatous degeneration of their cusps. Myxomatous degeneration is the most common cause of MVP and it can be associated with involvement of the other valves. Concomitant involvement of the aortic valve has been reported, however it is very rare and simultaneous involvement of the pulmonary valve has not been reported in the literature so far. We report a case of MVP associated with myxomatous degeneration of the tricuspid, pulmonary and aortic valves.

  20. In Vitro Evaluation of the iValve : A Novel Hands-Free Speech Valve

    NARCIS (Netherlands)

    van der Houwen, E.B.; van Kalkeren, T.A.; Burgerhof, J.G.; van der Laan, B.F.; Verkerke, G.J.

    2011-01-01

    Objectives: We performed in vitro evaluation of a novel, disposable, automatic hands-free tracheostoma speech valve for laryngectomy patients based upon the principle of inhalation. The commercially available automatic speech valves close upon strong exhalation and open again when the pressure drops

  1. Dynamic Heterogeneity of the Heart Valve Interstitial Cell Population in Mitral Valve Health and Disease

    Directory of Open Access Journals (Sweden)

    Tori E. Horne

    2015-08-01

    Full Text Available The heart valve interstitial cell (VIC population is dynamic and thought to mediate lay down and maintenance of the tri-laminar extracellular matrix (ECM structure within the developing and mature valve throughout life. Disturbances in the contribution and distribution of valve ECM components are detrimental to biomechanical function and associated with disease. This pathological process is associated with activation of resident VICs that in the absence of disease reside as quiescent cells. While these paradigms have been long standing, characterization of this abundant and ever-changing valve cell population is incomplete. Here we examine the expression pattern of Smooth muscle α-actin, Periostin, Twist1 and Vimentin in cultured VICs, heart valves from healthy embryonic, postnatal and adult mice, as well as mature valves from human patients and established mouse models of disease. We show that the VIC population is highly heterogeneous and phenotypes are dependent on age, species, location, and disease state. Furthermore, we identify phenotypic diversity across common models of mitral valve disease. These studies significantly contribute to characterizing the VIC population in health and disease and provide insights into the cellular dynamics that maintain valve structure in healthy adults and mediate pathologic remodeling in disease states.

  2. Coronary Emboli in a Young Patient with Mechanical Aortic Valve: A Rare Cause of Acute Myocardial Infarction

    Directory of Open Access Journals (Sweden)

    Arash Gholoobi

    2016-03-01

    Full Text Available Coronary artery embolism is an uncommon cause of Acute Myocardial Infarction (AMI. Herein, we reported a 24-year-old male who was admitted with acute infero-posterior myocardial infarction and cerebral Transient Ischemic Attack (TIA. He had undergone mechanical Aortic Valve Replacement (AVR surgery 6 years ago. Surprisingly, the patient had decided to stop taking his medication (warfarin 20 days earlier without any medical advice. Coronary angiography revealed a thrombus located at the distal part of the left circumflex artery. Discontinuation of anticoagulant therapy in the presence of mechanical valve prosthesis, clinical evidence of coincidental TIA, and lack of atherosclerotic risk factors were highly suggestive of coronary thromboembolism as the cause of AMI. Overall, this case report emphasized the necessity of continuous education in patients with mechanical heart valves to prevent such undesired events.

  3. Advanced microbial check valve development

    Science.gov (United States)

    Colombo, G. V.; Greenley, D. R.

    1980-01-01

    A flight certified assembly identified as a Microbial Check Valve (MCV) was developed and tested. The MCV is a canister packed with an iodinated anionic exchange resin. The device is used to destroy organisms in a water stream as the water passes through the device. The device is equally effective for fluid flow in either direction and its primary method of organism removal is killing rather than filtering. The MCV was successfully developed for the space shuttle to: disinfect fuel cell water; and prevent back contamination of the stored potable water supply. One version of the device consists of a high residual iodinated resin bed that imparts approximately 2 ppm of iodine to the fuel cell water as it flows to the potable water tanks. A second version of the device consists of a low residual iodinated resin bed. One of these low residual beds is located at each use port in the potable water system for the dual purpose of removing some iodine from the potable water as it is dispensed and also to prevent back contamination of the potable supply.

  4. Exuberant accessory mitral valve tissue with possible true parachute mitral valve: a case report

    Directory of Open Access Journals (Sweden)

    Nikolic Aleksandra

    2012-09-01

    Full Text Available Abstract Introduction A parachute mitral valve is defined as a unifocal attachment of mitral valve chordae tendineae independent of the number of papillary muscles. Data from the literature suggests that the valve can be distinguished on the basis of morphological features as either a parachute-like asymmetrical mitral valve or a true parachute mitral valve. A parachute-like asymmetrical mitral valve has two papillary muscles; one is elongated and located higher in the left ventricle. A true parachute mitral valve has a single papillary muscle that receives all chordae, as was present in our patient. Patients with parachute mitral valves during childhood have multilevel left-side heart obstructions, with poor outcomes without operative treatment. The finding of a parachute mitral valve in an adult patient is extremely rare, especially as an isolated lesion. In adults, the unifocal attachment of the chordae results in a slightly restricted valve opening and, more frequently, valvular regurgitation. Case presentation A 40-year-old Caucasian female patient was admitted to a primary care physician due to her recent symptoms of heart palpitation and chest discomfort on effort. Transthoracic echocardiography showed chordae tendineae which were elongated and formed an unusual net shape penetrating into left ventricle cavity. The parasternal short axis view of her left ventricle showed a single papillary muscle positioned on one side in the posteromedial commissure receiving all chordae. Her mitral valve orifice was slightly eccentric and the chordae were converting into a single papillary muscle. Mitral regurgitation was present and it was graded as moderate to severe. Her left atrium was enlarged. There were no signs of mitral stenosis or a subvalvular ring. She did not have a bicuspid aortic valve or coarctation of the ascending aorta. The dimensions and systolic function of her left ventricle were normal. Our patient had a normal body habitus

  5. Simulant Development for Hanford Tank Farms Double Valve Isolation (DVI) Valves Testing

    Energy Technology Data Exchange (ETDEWEB)

    Wells, Beric E.

    2012-12-21

    Leakage testing of a representative sample of the safety-significant isolation valves for Double Valve Isolation (DVI) in an environment that simulates the abrasive characteristics of the Hanford Tank Farms Waste Transfer System during waste feed delivery to the Waste Treatment and Immobilization Plant (WTP) is to be conducted. The testing will consist of periodic leak performed on the DVI valves after prescribed numbers of valve cycles (open and close) in a simulated environment representative of the abrasive properties of the waste and the Waste Transfer System. The valve operations include exposure to cycling conditions that include gravity drain and flush operation following slurry transfer. The simulant test will establish the performance characteristics and verify compliance with the Documented Safety Analysis. Proper simulant development is essential to ensure that the critical process streams characteristics are represented, National Research Council report “Advice on the Department of Energy's Cleanup Technology Roadmap: Gaps and Bridges”

  6. Recurrent stuck mitral valve: eosinophilia an unusual pathology.

    Science.gov (United States)

    Awasthy, Neeraj; Bhat, Yasser; Radhakrishnan, S; Sharma, Rajesh

    2015-03-01

    Eosinophilia is a very unusual and rare cause of thrombosis of prosthetic mitral valve. We report a 10-year-old male child of recurrent stuck prosthetic mitral valve. The child underwent mitral valve replacement for severe mitral regurgitation secondary to Rheumatic heart disease. He had recurrent prosthetic mitral valve thrombosis, despite desired INR levels. There was associated eosinophilia. The child was treated on the lines of tropical eosinophilia with oral prednisolone and diethylcarbamazine, the eosinophil count dropped significantly with no subsequent episode of stuck mitral valve. We discuss the management of recurrent stuck mitral valve and also eosinophilia as a causative factor for the same.

  7. Fluid dynamic characterization of a polymeric heart valve prototype (Poli-Valve) tested under continuous and pulsatile flow conditions.

    Science.gov (United States)

    De Gaetano, Francesco; Serrani, Marta; Bagnoli, Paola; Brubert, Jacob; Stasiak, Joanna; Moggridge, Geoff D; Costantino, Maria Laura

    2015-11-01

    Only mechanical and biological heart valve prostheses are currently commercially available. The former show longer durability but require anticoagulant therapy; the latter display better fluid dynamic behavior but do not have adequate durability. New Polymeric Heart Valves (PHVs) could potentially combine the hemodynamic properties of biological valves with the durability of mechanical valves. This work presents a hydrodynamic evaluation of 2 groups of newly developed supra-annular, trileaflet prosthetic heart valves made from styrenic block copolymers (SBC): Poli-Valves. 2 types of Poli-Valves made of SBC and differing in polystyrene fraction content were tested under continuous and pulsatile flow conditions as prescribed by ISO 5840 Standard. A pulse duplicator designed ad hoc allowed the valve prototypes to be tested at different flow rates and frequencies. Pressure and flow were recorded; pressure drops, effective orifice area (EOA), and regurgitant volume were computed to assess the behavior of the valve. Both types of Poli-Valves met the minimum requirements in terms of regurgitation and EOA as specified by the ISO 5840 Standard. Results were compared with 5 mechanical heart valves (MHVs) and 5 tissue heart valves (THVs), currently available on the market. Based on these results, PHVs based on styrenic block copolymers, as are Poli-Valves, can be considered a promising alternative for heart valve replacement in the near future.

  8. Fluid Dynamic Characterization of a Polymeric Heart Valve Prototype (Poli-Valve) tested under Continuous and Pulsatile Flow Conditions

    Science.gov (United States)

    De Gaetano, Francesco; Serrani, Marta; Bagnoli, Paola; Brubert, Jacob; Stasiak, Joanna; Moggridge, Geoff D.; Costantino, Maria Laura

    2016-01-01

    Introduction Only mechanical and biological heart valve prostheses are currently commercially available. The former show longer durability but require anticoagulant therapy, the latter display better fluid dynamic behaviour but do not have adequate durability. New Polymeric Heart Valves (PHVs) could potentially combine the haemodynamic properties of biological valves with the durability of mechanical valves. This work presents a hydrodynamic evaluation of two groups of newly developed supra-annular tri-leaflet prosthetic heart valves made from styrenic block copolymers (SBC): Poli-Valves. Methods Two types of Poli-Valves made of SBC differing in polystyrene fraction content were tested under continuous and pulsatile flow conditions as prescribed by ISO 5840 Standard. An ad - hoc designed pulse duplicator allowed the valve prototypes to be tested at different flow rates and frequencies. Pressure and flow were recorded; pressure drops, effective orifice area (EOA), and regurgitant volume were computed to assess the valve’s behaviour. Results Both types Poli-Valves met the minimum requirements in terms of regurgitation and EOA as specified by ISO 5840 Standard. Results were compared with five mechanical heart valves (MHVs) and five tissue heart valves (THVs), currently available on the market. Conclusion Based on these results, polymeric heart valves based on styrenic block copolymers, as Poli-Valves are, can be considered as promising alternative for heart valve replacement in near future. PMID:26689146

  9. Successful implantation of a second-generation aortic valve in severe aortic regurgitation secondary to a traumatic cusp lesion

    Energy Technology Data Exchange (ETDEWEB)

    Mangieri, Antonio [Cardio-Thoracic-Vascular Department, San Raffaele Institute, Milan (Italy); Latib, Azeem, E-mail: info@emocolumbus.it [Cardio-Thoracic-Vascular Department, San Raffaele Institute, Milan (Italy); EMO-GVM Centro Cuore Columbus, Milan (Italy); Aurelio, Andrea [Cardio-Thoracic-Vascular Department, San Raffaele Institute, Milan (Italy); Figini, Filippo [Cardio-Thoracic-Vascular Department, San Raffaele Institute, Milan (Italy); EMO-GVM Centro Cuore Columbus, Milan (Italy); Agricola, Eustachio; Rosa, Isabella; Stella, Stefano; Spagnolo, Pietro; Castiglioni, Alessandro [Cardio-Thoracic-Vascular Department, San Raffaele Institute, Milan (Italy); Colombo, Antonio [Cardio-Thoracic-Vascular Department, San Raffaele Institute, Milan (Italy); EMO-GVM Centro Cuore Columbus, Milan (Italy)

    2015-10-15

    A 67-year-old man with a dilated cardiomyopathy and severe aortic regurgitation (AR) secondary to a traumatic cusp lesion was referred to our institution because of progressive worsening of dyspnea. After formal discussion in the heart team, the patient was scheduled for TAVI (transcatheter aortic valve implantation). The pre procedural computed tomography scan revealed a minimum amount of calcium on the aortic valve and low position of coronary ostia. The TAVI procedure was performed with the implantation of a fully retrievable and repositionable aortic valve prosthesis (Direct Flow 29 mm, Direct Flow Medical, Santa Rosa, California) with an excellent result and no paravalvular leak. The TAVI devices designed for the treatment of calcific aortic stenosis have numerous limitations for the treatment of pure AR such as the risk of residual AR, the lack of repositionability and retrievability, and the need for valve- in-valve implantation. We believe that treatment of selected cases of pure AR with the Direct Flow valve is feasible and takes advantage of the retrievability of the prosthesis.

  10. Management of moderate functional tricuspid valve regurgitation at the time of pulmonary valve replacement: is concomitant tricuspid valve repair necessary?

    Science.gov (United States)

    Kogon, Brian; Patel, Manisha; Leong, Traci; McConnell, Michael; Book, Wendy

    2010-08-01

    Congenital heart defects with a component of pulmonary stenosis are often palliated in childhood by disrupting the pulmonary valve. Patients often undergo subsequent pulmonary valve replacement (PVR) to protect the heart from the consequences of pulmonary regurgitation. In the presence of associated moderate functional tricuspid valve (TV) regurgitation, it is unclear what factors contribute to persistent TV regurgitation following PVR. In particular, it is unknown whether PVR alone will reduce the right ventricular (RV) size and restore TV function or whether concomitant TV annuloplasty is required as well. Thirty-five patients were analyzed. Each patient underwent initial palliation of congenital pulmonary stenosis or tetralogy of Fallot, underwent subsequent PVR between 2002 and 2008, and had at least moderate TV regurgitation at the time of valve replacement. Serial echocardiograms were analyzed. Pulmonary and TV regurgitation, along with RV dilation and dysfunction, were scored (0, none; 1, mild; 2, moderate; 3, severe). RV volume and area were also calculated. Potential risk factors for persistent postoperative TV regurgitation were evaluated. One month following PVR, there was a significant reduction in pulmonary valve regurgitation (mean, 3 vs. 0.39; P regurgitation (mean, 2.33 vs. 1.3; P regurgitation postoperatively between those patients who underwent PVR alone and those who underwent concomitant tricuspid annuloplasty (mean, 1.29 vs. 1.31; P = 0.81). We conclude that following PVR, improvement in TV regurgitation and RV size occurs primarily in the first postoperative month. TV function improved to a similar degree with or without annuloplasty.

  11. Loss of Axin2 results in impaired heart valve maturation and subsequent myxomatous valve disease.

    Science.gov (United States)

    Hulin, Alexia; Moore, Vicky; James, Jeanne M; Yutzey, Katherine E

    2017-01-01

    Myxomatous valve disease (MVD) is the most common aetiology of primary mitral regurgitation. Recent studies suggest that defects in heart valve development can lead to heart valve disease in adults. Wnt/β-catenin signalling is active during heart valve development and has been reported in human MVD. The consequences of increased Wnt/β-catenin signalling due to Axin2 deficiency in postnatal valve remodelling and pathogenesis of MVD were determined. To investigate the role of Wnt/β-catenin signalling, we analysed heart valves from mice deficient in Axin2 (KO), a negative regulator of Wnt/β-catenin signalling. Axin2 KO mice display enlarged mitral and aortic valves (AoV) after birth with increased Wnt/β-catenin signalling and cell proliferation, whereas Sox9 expression and collagen deposition are decreased. At 2 months in Axin2 KO mice, the valve extracellular matrix (ECM) is stratified but distal AoV leaflets remain thickened and develop aortic insufficiency. Progressive myxomatous degeneration is apparent at 4 months with extensive ECM remodelling and focal aggrecan-rich areas, along with increased BMP signalling. Infiltration of inflammatory cells is also observed in Axin2 KO AoV prior to ECM remodelling. Overall, these features are consistent with the progression of human MVD. Finally, Axin2 expression is decreased and Wnt/β-catenin signalling is increased in myxomatous mitral valves in a murine model of Marfan syndrome, supporting the importance of Wnt/β-catenin signalling in the development of MVD. Altogether, these data indicate that Axin2 limits Wnt/β-catenin signalling after birth and allows proper heart valve maturation. Moreover, dysregulation of Wnt/β-catenin signalling resulting from loss of Axin2 leads to progressive MVD. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For Permissions, please email: journals.permissions@oup.com.

  12. Serotonin receptors and heart valve disease--it was meant 2B.

    Science.gov (United States)

    Hutcheson, Joshua D; Setola, Vincent; Roth, Bryan L; Merryman, W David

    2011-11-01

    Carcinoid heart disease was one of the first valvular pathologies studied in molecular detail, and early research identified serotonin produced by oncogenic enterochromaffin cells as the likely culprit in causing changes in heart valve tissue. Researchers and physicians in the mid-1960s noted a connection between the use of several ergot-derived medications with structures similar to serotonin and the development of heart valve pathologies similar to those observed in carcinoid patients. The exact serotonergic target that mediated valvular pathogenesis remained a mystery for many years until similar cases were reported in patients using the popular diet drug Fen-Phen in the late 1990s. The Fen-Phen episode sparked renewed interest in serotonin-mediated valve disease, and studies led to the identification of the 5-HT(2B) receptor as the likely molecular target leading to heart valve tissue fibrosis. Subsequent studies have identified numerous other activators of the 5-HT(2B) receptor, and consequently, the use of many of these molecules has been linked to heart valve disease. Herein, we: review the molecular properties of the 5-HT(2B) receptor including factors that differentiate the 5-HT(2B) receptor from other 5-HT receptor subtypes, discuss the studies that led to the identification of the 5-HT(2B) receptor as the mediator of heart valve disease, present current efforts to identify potential valvulopathogens by screening for 5-HT(2B) receptor activity, and speculate on potential therapeutic benefits of 5-HT(2B) receptor targeting. Copyright © 2011. Published by Elsevier Inc.

  13. Reconstructive valve surgery within 10 days of stroke in endocarditis.

    Science.gov (United States)

    Raman, Jai; Ballal, Apoorva; Hota, Bala; Mirza, Sara; Lai, David; Bleck, Thomas; Lateef, Omar

    2016-07-01

    The optimal timing of surgical treatment for infective endocarditis complicated by cerebrovascular events is controversial, largely due to the perceived risk of perioperative intracranial bleeding. Current guidelines suggest waiting 2 weeks between the diagnosis of stroke and surgery. The aim of this study was to investigate the clinical and neurological outcomes of early surgery following a stroke. This was a single-center retrospective analysis of 12 consecutive patients requiring surgery for infective endocarditis between 2011 and 2014 at Rush University Medical Center, with either ischemic (n = 6) and/or hemorrhagic (n = 6) cerebrovascular complications. All underwent computed tomographic angiography prior to early valve reconstructive surgery to identify potentially actionable neurological findings. Early valve surgery was performed for ongoing sepsis or persistent emboli. Neurologic risk and outcome were assessed pre- and postoperatively using the National Institutes of Health Stroke Scale and the Glasgow Outcome Scale, respectively. All 12 patients underwent surgical treatment within 10 days of the diagnosis of stroke. Mortality in the immediate postoperative period was 8%. Eleven of the 12 patients exhibited good neurological recovery in the immediate postoperative period, with a Glasgow Outcome Scale score ≥ 3. There was no correlation between duration of cardiopulmonary bypass and neurological outcomes. Early cardiac surgery in patients with infective endocarditis and stroke maybe lifesaving with a low neurological risk. Comprehensive neurovascular imaging may help in identifying patient-related risk factors. © The Author(s) 2016.

  14. Traumatic avulsion of the tricuspid valve after gas bottle explosion

    Directory of Open Access Journals (Sweden)

    Francesca Tedoldi

    2016-06-01

    Full Text Available We present a very rare example of chronic right heart failure caused by torrent tricuspid regurgitation. Massive right heart dilatation and severe tricuspid regurgitation due to avulsion of the tricuspid valve apparatus occurred as a result of a blunt chest trauma following the explosion of a gas bottle 20 years before admission, when the patient was a young man in Vietnam. After this incident, the patient went through a phase of severe illness, which can retrospectively be identified as an acute right heart decompensation with malaise, ankle edema, and dyspnea. Blunt chest trauma caused by explosives leading to valvular dysfunction has not been reported in the literature so far. It is remarkable that the patient not only survived this trauma, but had been managing his chronic heart failure well without medication for over 20 years. Learning points: • Thorough clinical and physical examination remains the key to identifying patients with relevant valvulopathies. • With good acoustic windows, TTE is superior to TEE in visualizing the right heart. • Traumatic avulsion of valve apparatus is a rare but potentially life-threatening complication of blunt chest trauma and must be actively sought for. Transthoracic echocardiography remains the method of choice in these patients.

  15. Traumatic avulsion of the tricuspid valve after gas bottle explosion

    Science.gov (United States)

    Krisper, Maximilian; Köhncke, Clemens; Pieske, Burkert

    2016-01-01

    Summary We present a very rare example of chronic right heart failure caused by torrent tricuspid regurgitation. Massive right heart dilatation and severe tricuspid regurgitation due to avulsion of the tricuspid valve apparatus occurred as a result of a blunt chest trauma following the explosion of a gas bottle 20 years before admission, when the patient was a young man in Vietnam. After this incident, the patient went through a phase of severe illness, which can retrospectively be identified as an acute right heart decompensation with malaise, ankle edema, and dyspnea. Blunt chest trauma caused by explosives leading to valvular dysfunction has not been reported in the literature so far. It is remarkable that the patient not only survived this trauma, but had been managing his chronic heart failure well without medication for over 20 years. Learning points Thorough clinical and physical examination remains the key to identifying patients with relevant valvulopathies.With good acoustic windows, TTE is superior to TEE in visualizing the right heart.Traumatic avulsion of valve apparatus is a rare but potentially life-threatening complication of blunt chest trauma and must be actively sought for. Transthoracic echocardiography remains the method of choice in these patients. PMID:27249554

  16. Presentation of the development of the SRV valve (safety relief valve); Presentation du developpement de la vanne SRV (Safety Relief Valve)

    Energy Technology Data Exchange (ETDEWEB)

    Manguette, P. [Adareg, 59 - Haubourdin (France)

    1998-09-01

    Adareg has 30 years experience in Hydrane and control valves. Its know-how moves towards extreme technologies: control of all types of fluids (hot, cold, aggressive ones, clean ones etc... ). A perfect control is essential for very low temperatures (nuclear submarines, Ariane). Adareg Research and Development activities, certified ISO 9001, have developed valves accepting temperatures reaching 2 degrees above the absolute 0. Increasing requirements concerning low temperatures have encouraged Adareg to develop a research programme in partnership with CEA - French Atomic Energy Commission - for valves type 'SRV' (Safety Relief Valves). This type of valve is designed for a new accelerator of particles, the LHC, at CERN, in Geneva. (author)

  17. Survey of industrial coal conversion equipment capabilities: valves

    Energy Technology Data Exchange (ETDEWEB)

    Bush, W. A.; Slade, E. C.

    1978-06-01

    A survey of the industrial capabilities of the valve and valve-actuator industry to supply large, high-pressure stop valves for the future coal conversion industry is presented in this report. Also discussed are development and testing capabilities of valve and valve-actuator manufacturers and anticipated lead times required to manufacture advanced design valves for the most stringent service applications. Results indicate that the valve and valve-actuator industry is capable of manufacturing in quantity equipment of the size and for the pressure and temperature ranges which would be required in the coal conversion industry. Valve manufacturers do not, however, have sufficient product application experience to predict the continuing functional ability of valves used for lock-hopper feeders, slurry feeders, and slag-char letdown service. Developmental and testing efforts to modify existing valve designs or to develop new valve concepts for these applications were estimated to range from 1 to 6 years. A testing facility to simulate actuation of critical valves under service conditions would be beneficial.

  18. A capillary valve for microfluidic systems.

    Energy Technology Data Exchange (ETDEWEB)

    Cummings, Eric B.; Kanouff, Michael P.; Rush, Brian M.

    2004-10-01

    Microfluidic systems are becoming increasingly complicated as the number of applications grows. The use of microfluidic systems for chemical and biological agent detection, for example, requires that a given sample be subjected to many process steps, which requires microvalves to control the position and transport of the sample. Each microfluidic application has its own specific valve requirements and this has precipitated the wide variety of valve designs reported in the literature. Each of these valve designs has its strengths and weaknesses. The strength of the valve design proposed here is its simplicity, which makes it easy to fabricate, easy to actuate, and easy to integrate with a microfluidic system. It can be applied to either gas phase or liquid phase systems. This novel design uses a secondary fluid to stop the flow of the primary fluid in the system. The secondary fluid must be chosen based on the type of flow that it must stop. A dielectric fluid must be used for a liquid phase flow driven by electroosmosis, and a liquid with a large surface tension should be used to stop a gas phase flow driven by a weak pressure differential. Experiments were carried out investigating certain critical functions of the design. These experiments verified that the secondary fluid can be reversibly moved between its 'valve opened' and 'valve closed' positions, where the secondary fluid remained as one contiguous piece during this transport process. The experiments also verified that when Fluorinert is used as the secondary fluid, the valve can break an electric circuit. It was found necessary to apply a hydrophobic coating to the microchannels to stop the primary fluid, an aqueous electrolyte, from wicking past the Fluorinert and short-circuiting the valve. A simple model was used to develop valve designs that could be closed using an electrokinetic pump, and re-opened by simply turning the pump off and allowing capillary forces to push the secondary

  19. Fabrication of micro metallic valve and pump

    Science.gov (United States)

    Yang, Ming; Kabasawa, Yasunari; Ito, Kuniyoshi

    2010-03-01

    Fabrication of micro devices by using micro metal forming was proposed by the authors. We developed a desktop servo-press machine with precise tooling system. Precise press forming processes including micro forging and micro joining has been carried out in a progressive die. In this study, micro metallic valve and pump were fabricated by using the precise press forming. The components are made of sheet metals, and assembled in to a unit in the progressive die. A micro check-valve with a diameter of 3mm and a length of 3.2mm was fabricated, and the property of flow resistance was evaluated. The results show that the check valve has high property of leakage proof. Since the valve is a unit parts with dimensions of several millimeters, it has advantage to be adapted to various pump design. Here, two kinds of micro pumps with the check-valves were fabricated. One is diaphragm pump actuated by vibration of the diaphragm, and another is tube-shaped pump actuated by resonation. The flow quantities of the pumps were evaluated and the results show that both of the pumps have high pumping performance.

  20. Lymphangiogenesis is increased in heart valve endocarditis.

    Science.gov (United States)

    Niinimäki, Eetu; Mennander, Ari A; Paavonen, Timo; Kholová, Ivana

    2016-09-15

    Inflammation-associated lymphangiogenesis (IAL) has been identified as part of several acute and chronic inflammation. Sparse data exist on lymphatics during endocarditis. Fifty-two patients with surgically resected valves were included. Endocarditis was present in 18 aortic and 10 mitral valves. Controls consisted of 15 degenerative aortic and 9 degenerative mitral valves. There were 22 males with endocarditis and 17 males in controls. The mean age was 58 (SD 15) years with endocarditis vs. 62 (SD 13) years for controls. Lymphatics were detected by podoplanin antibody immunohistochemistry and morphometrical analysis was performed. The lymphatic density in endocarditis was 833 (SD 529) vessels/mm(2) (range 0-1707) as compared with 39 (SD 60) vessels/mm(2) (range 0-250) in controls (p=0.000). In endocarditis, the mean lymphatic size was 153 (SD 372) μm(2) ranging from 1 to 2034μm(2), whereas it was 30 (SD 29) μm(2), with maximum 90μm(2) and minimum 2μm(2) in controls (p=0.000). IAL is increased in valves with endocarditis as compared with controls. Lymphatics in heart valves may provide a novel means for treatment strategies against endocarditis. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.