The British Interplanetary Society - Val Cleaver and Wernher von Braun

NASA Astrophysics Data System (ADS)

Willhite, I. P.

This article is concerned with the early relationship between Wernher von Braun and the British Interplanetary Society (BIS). The BIS/Wernher von Braun/Val Cleaver correspondence files located here at the US Space & Rocket Center in Huntsville, Alabama are unparalleled. As one reads the stimulating comments between Cleaver and von Braun, the need to share their thoughts prevails. Following is an excerpt from one letter that whets ones appetite for more. 10 June 1951 Cleaver writes, “I'm so glad you enjoyed my last letter, and look forward to your promised further contribution to our discussion of the ethics of science in general and astronautics in particu- lar. As regards the one particular point on which you found yourself unable to hold your fire, I should say there are really two distinct issues at stake:. . .” This article attempts to represent the best of the letters as they goad each other on scientific principles, means to prevent wars, and other philosophic ideas.

British Thoracic Society quality standards for the investigation and management of pulmonary nodules.

PubMed

Baldwin, David; Callister, Matthew; Akram, Ahsan; Cane, Paul; Draffan, Jeanette; Franks, Kevin; Gleeson, Fergus; Graham, Richard; Malhotra, Puneet; Pearson, Philip; Subesinghe, Manil; Waller, David; Woolhouse, Ian

2018-01-01

The purpose of the quality standards document is to provide healthcare professionals, commissioners, service providers and patients with a guide to standards of care that should be met for the investigation and management of pulmonary nodules in the UK, together with measurable markers of good practice. Development of British Thoracic Society (BTS) Quality Standards follows the BTS process of quality standard production based on the National Institute for Health and Care Excellence process manual for the development of quality standards. 7 quality statements have been developed, each describing a key marker of high-quality, cost-effective care for the investigation and management of pulmonary nodules, and each statement is supported by quality measures that aim to improve the structure, process and outcomes of healthcare. BTS Quality Standards for the investigation and management of pulmonary nodules form a key part of the range of supporting materials that the Society produces to assist in the dissemination and implementation of guideline recommendations.

British Thoracic Society quality standards for the investigation and management of pulmonary nodules

PubMed Central

Baldwin, David; Callister, Matthew; Akram, Ahsan; Cane, Paul; Draffan, Jeanette; Franks, Kevin; Gleeson, Fergus; Graham, Richard; Malhotra, Puneet; Pearson, Philip; Subesinghe, Manil; Waller, David; Woolhouse, Ian

2018-01-01

Introduction The purpose of the quality standards document is to provide healthcare professionals, commissioners, service providers and patients with a guide to standards of care that should be met for the investigation and management of pulmonary nodules in the UK, together with measurable markers of good practice. Methods Development of British Thoracic Society (BTS) Quality Standards follows the BTS process of quality standard production based on the National Institute for Health and Care Excellence process manual for the development of quality standards. Results 7 quality statements have been developed, each describing a key marker of high-quality, cost-effective care for the investigation and management of pulmonary nodules, and each statement is supported by quality measures that aim to improve the structure, process and outcomes of healthcare. Discussion BTS Quality Standards for the investigation and management of pulmonary nodules form a key part of the range of supporting materials that the Society produces to assist in the dissemination and implementation of guideline recommendations. PMID:29682290

The British society for gynaecological endoscopy endometriosis centres project.

PubMed

Saridogan, Ertan; Byrne, Dominic

2013-01-01

Management of advanced endometriosis frequently requires a multidisciplinary team approach and international guidelines suggest treatment in centres of expertise. Due to variability of published outcome data, prospective data collection and standardisation of reporting systems have been suggested to improve our understanding of surgical outcomes. The British Society for Gynaecological Endoscopy (BSGE) Endometriosis Centres were established to manage rectovaginal endometriosis, to collect treatment and outcome data, and to provide these data to patients, clinicians and healthcare commissioners. The BSGE Endometriosis Centres Project works on the principle of voluntary participation. Centres that would like to be recognised or accredited as a BSGE Endometriosis Centre need to fulfil a number of basic requirements including working in appropriate multidisciplinary clinical teams, auditing their outcome and having sufficient workload to maintain their surgical skills. The project has already had an impact on where the patients with advanced endometriosis are treated in the United Kingdom. Patients and healthcare professionals are becoming aware of their presence and more patients with the condition are being referred to these centres. It is also expected that the accredited centre status would be required for funding by healthcare commissioners for this type endometriosis. Copyright © 2013 S. Karger AG, Basel.

Gait Speed Predicts 30-Day Mortality After Transcatheter Aortic Valve Replacement: Results From the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry.

PubMed

Alfredsson, Joakim; Stebbins, Amanda; Brennan, J Matthew; Matsouaka, Roland; Afilalo, Jonathan; Peterson, Eric D; Vemulapalli, Sreekanth; Rumsfeld, John S; Shahian, David; Mack, Michael J; Alexander, Karen P

2016-04-05

Surgical risk scores do not include frailty assessments (eg, gait speed), which are of particular importance for patients with severe aortic stenosis considering transcatheter aortic valve replacement. We assessed the association of 5-m gait speed with outcomes in a cohort of 8039 patients who underwent transcatheter aortic valve replacement (November 2011-June 2014) and were included in the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry. We evaluated the association between continuous and categorical gait speed and 30-day all-cause mortality before and after adjustment for Society of Thoracic Surgeons-predicted risk of mortality score and key variables. Secondary outcomes included in-hospital mortality, bleeding, acute kidney injury, and stroke. The overall median gait speed was 0.63 m/s (25th-75th percentile, 0.47-0.79 m/s), with the slowest walkers (<0.5 m/s) constituting 28%, slow walkers (0.5-0.83 m/s) making up 48%, and normal walkers (>0.83 m/s) constituting 24% of the population. Thirty-day all-cause mortality rates were 8.4%, 6.6%, and 5.4% for the slowest, slow, and normal walkers, respectively (P<0.001). Each 0.2-m/s decrease in gait speed corresponded to an 11% increase in 30-day mortality (adjusted odds ratio, 1.11; 95% confidence interval, 1.01-1.22). The slowest walkers had 35% higher 30-day mortality than normal walkers (adjusted odds ratio, 1.35; 95% confidence interval, 1.01-1.80), significantly longer hospital stays, and a lower probability of being discharged to home. Gait speed is independently associated with 30-day mortality after transcatheter aortic valve replacement. Identification of frail patients with the slowest gait speeds facilitates preprocedural evaluation and anticipation of a higher level of postprocedural care. URL: http://www.clinicaltrials.gov. Unique identifier: NCT01737528. © 2016 American Heart Association, Inc.

Diagnosis and management of adult coeliac disease: guidelines from the British Society of Gastroenterology

PubMed Central

Ludvigsson, Jonas F; Bai, Julio C; Biagi, Federico; Card, Timothy R; Ciacci, Carolina; Ciclitira, Paul J; Green, Peter H R; Hadjivassiliou, Marios; Holdoway, Anne; van Heel, David A; Kaukinen, Katri; Leffler, Daniel A; Leonard, Jonathan N; Lundin, Knut E A; McGough, Norma; Davidson, Mike; Murray, Joseph A; Swift, Gillian L; Walker, Marjorie M; Zingone, Fabiana; Sanders, David S

2014-01-01

A multidisciplinary panel of 18 physicians and 3 non-physicians from eight countries (Sweden, UK, Argentina, Australia, Italy, Finland, Norway and the USA) reviewed the literature on diagnosis and management of adult coeliac disease (CD). This paper presents the recommendations of the British Society of Gastroenterology. Areas of controversies were explored through phone meetings and web surveys. Nine working groups examined the following areas of CD diagnosis and management: classification of CD; genetics and immunology; diagnostics; serology and endoscopy; follow-up; gluten-free diet; refractory CD and malignancies; quality of life; novel treatments; patient support; and screening for CD. PMID:24917550

Christianity and Eugenics: The Place of Religion in the British Eugenics Education Society and the American Eugenics Society, c.1907–1940

PubMed Central

Baker, Graham J.

2014-01-01

Historians have regularly acknowledged the significance of religious faith to the eugenics movement in Britain and the USA. However, much of this scholarship suggests a polarised relationship of either conflict or consensus. Where Christian believers participated in the eugenics movement this has been represented as an abandonment of ‘orthodox’ theology, and the impression has been created that eugenics was a secularising force. In contrast, this article explores the impact of religious values on two eugenics organisations: the British Eugenics Education Society, and the American Eugenics Society. It is demonstrated that concerns over religion resulted in both these organisations modifying and tempering the public work that they undertook. This act of concealing and minimising the visibly controversial aspects of eugenics is offered as an addition to the debate over ‘mainline’ versus ‘reform’ eugenics. PMID:24778464

Transcatheter mitral valve repair in osteogenesis imperfecta associated mitral valve regurgitation.

PubMed

van der Kley, Frank; Delgado, Victoria; Ajmone Marsan, Nina; Schalij, Martin J

2014-08-01

Osteogenesis imperfecta is associated with increased prevalence of significant mitral valve regurgitation. Surgical mitral valve repair and replacement are feasible but are associated with increased risk of bleeding and dehiscence of implanted valves may occur more frequently. The present case report describes the outcomes of transcatheter mitral valve repair in a patient with osteogenesis imperfecta. A 60 year-old patient with osteogenesis imperfecta and associated symptomatic moderate to severe mitral regurgitation underwent transthoracic echocardiography which showed a nondilated left ventricle with preserved systolic function and moderate to severe mitral regurgitation. On transoesophageal echocardiography the regurgitant jet originated between the anterolateral scallops of the anterior and posterior leaflets (A1-P1). Considering the comorbidities associated with osteogenesis imperfecta the patient was accepted for transcatheter mitral valve repair using the Mitraclip device (Abbott vascular, Menlo, CA). Under fluoroscopy and 3D transoesophageal echocardiography guidance, a Mitraclip device was implanted between the anterolateral and central scallops with significant reduction of mitral regurgitation. The postoperative evolution was uneventful. At one month follow-up, transthoracic echocardiography showed a stable position of the Mitraclip device with no mitral regurgitation. Transcatheter mitral valve repair is feasible and safe in patients with osteogenesis imperfecta and associated symptomatic significant mitral regurgitation. Copyright © 2014 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

ACC/AATS/AHA/ASE/EACTS/HVS/SCA/SCAI/SCCT/SCMR/STS 2017 Appropriate Use Criteria for the Treatment of Patients With Severe Aortic Stenosis: A Report of the American College of Cardiology Appropriate Use Criteria Task Force, American Association for Thoracic Surgery, American Heart Association, American Society of Echocardiography, European Association for Cardio-Thoracic Surgery, Heart Valve Society, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance, and Society of Thoracic Surgeons.

PubMed

Bonow, Robert O; Brown, Alan S; Gillam, Linda D; Kapadia, Samir R; Kavinsky, Clifford J; Lindman, Brian R; Mack, Michael J; Thourani, Vinod H; Dehmer, Gregory J; Bonow, Robert O; Lindman, Brian R; Beaver, Thomas M; Bradley, Steven M; Carabello, Blase A; Desai, Milind Y; George, Isaac; Green, Philip; Holmes, David R; Johnston, Douglas; Leipsic, Jonathon; Mick, Stephanie L; Passeri, Jonathan J; Piana, Robert N; Reichek, Nathaniel; Ruiz, Carlos E; Taub, Cynthia C; Thomas, James D; Turi, Zoltan G; Doherty, John U; Dehmer, Gregory J; Bailey, Steven R; Bhave, Nicole M; Brown, Alan S; Daugherty, Stacie L; Dean, Larry S; Desai, Milind Y; Duvernoy, Claire S; Gillam, Linda D; Hendel, Robert C; Kramer, Christopher M; Lindsay, Bruce D; Manning, Warren J; Mehrotra, Praveen; Patel, Manesh R; Sachdeva, Ritu; Wann, L Samuel; Winchester, David E; Allen, Joseph M

2018-02-01

The American College of Cardiology collaborated with the American Association for Thoracic Surgery, American Heart Association, American Society of Echocardiography, European Association for Cardio-Thoracic Surgery, Heart Valve Society, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance, and Society of Thoracic Surgeons to develop and evaluate Appropriate Use Criteria (AUC) for the treatment of patients with severe aortic stenosis (AS). This is the first AUC to address the topic of AS and its treatment options, including surgical aortic valve replacement (SAVR) and transcatheter aortic valve replacement (TAVR). A number of common patient scenarios experienced in daily practice were developed along with assumptions and definitions for those scenarios, which were all created using guidelines, clinical trial data, and expert opinion in the field of AS. The 2014 AHA/ACC guideline for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines(1) and its 2017 focused update paper (2) were used as the primary guiding references in developing these indications. The writing group identified 95 clinical scenarios based on patient symptoms and clinical presentation, and up to 6 potential treatment options for those patients. A separate, independent rating panel was asked to score each indication from 1 to 9, with 1-3 categorized as "Rarely Appropriate," 4-6 as "May Be Appropriate," and 7-9 as "Appropriate." After considering factors such as symptom status, left ventricular (LV) function, surgical risk, and the presence of concomitant coronary or other valve disease, the rating panel determined that either SAVR or TAVR is Appropriate in most patients with symptomatic AS at intermediate or high surgical risk; however, situations

Are you British or Muslim; Can You be Both?

DTIC Science & Technology

2009-05-21

maintain a traditional British identity has reduced the aspiration of immigrants to assimilate into the broader culture and society of their “ new ...maintain a traditional British identity has reduced the aspiration of immigrants to assimilate into the broader culture and society of their ― new ...1 Anthony King, ―What does it mean to be British?‖ Daily Telegraph, http://www.telegraph.co.uk/ news /uknews/4196988/What-does-it

Regional Systems of Care to Optimize Outcomes in Patients Undergoing Transcatheter Aortic Valve Replacement.

PubMed

Stub, Dion; Lauck, Sandra; Lee, May; Gao, Min; Humphries, Karin; Chan, Albert; Cheung, Anson; Cook, Richard; Della Siega, Anthony; Leipsic, Jonathon; Charania, Jay; Dvir, Danny; Latham, Tim; Polderman, Jopie; Robinson, Simon; Wong, Daniel; Thompson, Christopher R; Wood, David; Ye, Jian; Webb, John

2015-12-28

This study sought to describe the development of a multicenter, transcatheter aortic valve replacement program and regional systems of care intended to optimize coordinated, efficient, and appropriate delivery of this new therapy. Transcatheter aortic valve replacement (TAVR) has become an accepted treatment option for patients with severe aortic stenosis who are at high surgical risk. Regional systems of care have led to improvements in outcomes for patients undergoing intervention for myocardial infarction, cardiac arrest, and stroke. We implemented a regional system of care for patients undergoing TAVR in British Columbia, Canada. We describe a prospective observational cohort of 583 patients who underwent TAVR in British Columbia between 2012 and 2014. Regionalization of TAVR care in British Columbia refers to a centrally coordinated, funded, and evaluated program led by a medical director and a multidisciplinary advisory group that oversees planning, access to care, and quality of outcomes at the 4 provincial sites. Risk-stratified case selection for transfemoral TAVR is performed by heart teams at each site on the basis of consensus provincial indications. Referrals for lower volume and more complicated TAVR, including nontransfemoral access and valve-in-valve procedures, are concentrated at a single site. In-hospital and 30-day outcomes are reported. The median age was 83 years (interquartile range [IQR]: 78 to 87 years) and median STS score was 6% (IQR: 4% to 8%). Transfemoral access was performed in 499 (85.6%) cases and nontransfemoral in 84 (14.4%). Transcatheter valve-in-valve procedures in for failed bioprosthetic valves were performed in 43 patients (7.4%). A balloon-expandable valve was inserted in 386 (66.2%) and a self-expanding valve in 189 (32.4%). All-cause 30-day mortality was 3.5%. All-cause in-hospital mortality and disabling stroke occurred in 3.1% and 1.9%, respectively. Median length of stay was 3 days (IQR: 3 to 6 days), with 92.8% of

Guidelines for transoesophageal echocardiographic probe cleaning and disinfection from the British Society of Echocardiography.

PubMed

Kanagala, P; Bradley, C; Hoffman, P; Steeds, R P

2011-10-01

The clinical utility of transoesophageal echocardiography (TOE) is well established. Being a semi-invasive procedure, however, the potential for transmission of infection between sequential patients exists. This has implications for the protection of both patients and medical staff. Guidelines for disinfection during gastrointestinal endoscopy (GIE) have been in place for many years.(1,2) Unfortunately, similar guidance is lacking with respect to TOE. Although traversing the same body cavities and sharing many similarities with upper GIE, there are fundamental structural and procedural differences with TOE which merit special consideration in establishing a decontamination protocol. This document provides recommendations for TOE probe decontamination based on the available evidence, expert opinion, and modification of the current British Society of Gastroenterology guidelines.

[Commentary by the German Society for Thoracic and Cardiovascular Surgery on the positions statement by the German Cardiology Society on quality criteria for transcatheter aortic valve implantation (TAVI)].

PubMed

Cremer, Jochen; Heinemann, Markus K; Mohr, Friedrich Wilhelm; Diegeler, Anno; Beyersdorf, Friedhelm; Niehaus, Heidi; Ensminger, Stephan; Schlensak, Christian; Reichenspurner, Hermann; Rastan, Ardawan; Trummer, Georg; Walther, Thomas; Lange, Rüdiger; Falk, Volkmar; Beckmann, Andreas; Welz, Armin

2014-12-01

Surgical aortic valve replacement is still considered the first-line treatment for patients suffering from severe aortic valve stenosis. In recent years, transcatheter aortic valve implantation (TAVI) has emerged as an alternative for selected high-risk patients. According to the latest results of the German external quality assurance program, mandatory by law, the initially very high mortality and procedural morbidity have now decreased to approximately 6 and 12%, respectively. Especially in Germany, the number of patients treated by TAVI has increased exponentially. In 2013, a total of 10.602 TAVI procedures were performed. TAVI is claimed to be minimally invasive. This is true concerning the access, but it does not describe the genuine complexity of the procedure, defined by the close neighborhood of the aortic valve to delicate intracardiac structures. Hence, significant numbers of life-threatening complications may occur and have been reported. Owing to the complexity of TAVI, there is a unanimous concordance between cardiologists and cardiac surgeons in the Western world demanding a close heart team approach for patient selection, intervention, handling of complications, and pre- as well as postprocedural care, respectively. The prerequisite is that TAVI should not be performed in centers with no cardiac surgery on site. This is emphasized in all international joint guidelines and expert consensus statements. Today, a small number of patients undergo TAVI procedures in German hospitals without a department of cardiac surgery on site. To be noted, most of these hospitals perform less than 20 cases per year. Recently, the German Cardiac Society (DGK) published a position paper supporting this practice pattern. Contrary to this statement and concerned about the safety of patients treated this way, the German Society for Thoracic and Cardiovascular Surgery (DGTHG) still fully endorses the European (ESC/EACTS) and other actual international guidelines and

Early Outcomes for Valve-in-valve Transcatheter Aortic Valve Replacement in Degenerative Freestyle Bioprostheses.

PubMed

Sang, Stephane Leung Wai; Beute, Tyler; Heiser, John; Berkompas, Duane; Fanning, Justin; Merhi, William

2017-11-20

Transcatheter aortic valve replacement (TAVR) is used increasingly to treat bioprosthetic valve failure. A paucity of data exists regarding valve-in-valve (ViV) TAVR in degenerated Freestyle stentless bioprostheses (FSBs). This study sought to evaluate the feasibility and short-term outcomes of ViV TAVR in previously placed FSB. From October 2014 to September 2016, 22 patients at a single institution underwent ViV TAVR with a self-expanding transcatheter valve for a failing FSB. Patient baseline characteristics and clinical outcomes data were collected retrospectively and entered into a dedicated database. The mean patient age was 74 ± 9years, and the mean Society of Thoracic Surgeons' Risk score was 9.0 ± 7.4%. Ten patients presented with acute heart failure requiring urgent intervention. The most common mode of failure of the FSB was regurgitation caused by a flail or malcoapting leaflet. Seventeen (77%) patients had a modified subcoronary implantation, 3 (14%) had a full root replacement, and 2 (9%) had a root inclusion. Device success using a self-expanding transcatheter valve was 95%, all via transfemoral approach. The mean implant depth was 7 ± 3 mm. Thirty-day survival was 100%. No patient had more than mild paravalvular regurgitation at 30days, and the permanent pacemaker rate was 9%. The mean hospital stay after intervention was 5 ± 2days. ViV TAVR using a self-expanding transcatheter valve is safe, feasible, and can be used successfully to treat a failed FSB. Procedural challenges suggest referral to valve centers of excellence. Copyright © 2017 Elsevier Inc. All rights reserved.

Muslims, Home Education and Risk in British Society

ERIC Educational Resources Information Center

Myers, Martin; Bhopal, Kalwant

2018-01-01

The number of families who choose to home educate has significantly increased in the last decade. This article explores the experiences of British Muslims who home educate using data from a larger study exploring the views of a diverse range of families. Drawing on the work of Beck, we discuss how 'risk' is understood in relation to Muslim home…

Aortic valve insufficiency in the teenager and young adult: the role of prosthetic valve replacement.

PubMed

Bradley, Scott M

2013-10-01

The contents of this article were presented in the session "Aortic insufficiency in the teenager" at the congenital parallel symposium of the 2013 Society of Thoracic Surgeons (STS) annual meeting. The accompanying articles detail the approaches of aortic valve repair and the Ross procedure.(1,2) The current article focuses on prosthetic valve replacement. For many young patients requiring aortic valve surgery, either aortic valve repair or a Ross procedure provides a good option. The advantages include avoidance of anticoagulation and potential for growth. In other patients, a prosthetic valve is an appropriate alternative. This article discusses the current state of knowledge regarding mechanical and bioprosthetic valve prostheses and their specific advantages relative to valve repair or a Ross procedure. In current practice, young patients requiring aortic valve surgery frequently undergo valve replacement with a prosthetic valve. In STS adult cardiac database, among patients ≤30 years of age undergoing aortic valve surgery, 34% had placement of a mechanical valve, 51% had placement of a bioprosthetic valve, 9% had aortic valve repair, and 2% had a Ross procedure. In the STS congenital database, among patients 12 to 30 years of age undergoing aortic valve surgery, 21% had placement of a mechanical valve, 18% had placement of a bioprosthetic valve, 30% had aortic valve repair, and 24% had a Ross procedure. In the future, the balance among these options may be altered by design improvements in prosthetic valves, alternatives to warfarin, the development of new patch materials for valve repair, and techniques to avoid Ross autograft failure.

Diagnosis and management of adult coeliac disease: guidelines from the British Society of Gastroenterology.

PubMed

Ludvigsson, Jonas F; Bai, Julio C; Biagi, Federico; Card, Timothy R; Ciacci, Carolina; Ciclitira, Paul J; Green, Peter H R; Hadjivassiliou, Marios; Holdoway, Anne; van Heel, David A; Kaukinen, Katri; Leffler, Daniel A; Leonard, Jonathan N; Lundin, Knut E A; McGough, Norma; Davidson, Mike; Murray, Joseph A; Swift, Gillian L; Walker, Marjorie M; Zingone, Fabiana; Sanders, David S

2014-08-01

A multidisciplinary panel of 18 physicians and 3 non-physicians from eight countries (Sweden, UK, Argentina, Australia, Italy, Finland, Norway and the USA) reviewed the literature on diagnosis and management of adult coeliac disease (CD). This paper presents the recommendations of the British Society of Gastroenterology. Areas of controversies were explored through phone meetings and web surveys. Nine working groups examined the following areas of CD diagnosis and management: classification of CD; genetics and immunology; diagnostics; serology and endoscopy; follow-up; gluten-free diet; refractory CD and malignancies; quality of life; novel treatments; patient support; and screening for CD. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

British Thoracic Society community acquired pneumonia guideline and the NICE pneumonia guideline: how they fit together

PubMed Central

Lim, W S; Smith, D L; Wise, M P; Welham, S A

2015-01-01

The British Thoracic Society (BTS) guideline for the management of adults with community acquired pneumonia (CAP) published in 2009 was compared with the 2014 National Institute for Health and Care Excellence (NICE) Pneumonia Guideline. Of the 36 BTS recommendations that overlapped with NICE recommendations, no major differences were found in 31, including those covering key aspects of CAP management: timeliness of diagnosis and treatment, severity assessment and empirical antibiotic choice. Of the five BTS recommendations where major differences with NICE were identified, one related to antibiotic duration in low and moderate severity CAP, two to the timing of review of patients and two to legionella urinary antigen testing. PMID:25977290

Education and Awareness Raising Activities of the British Society of Soil Science

NASA Astrophysics Data System (ADS)

Towers, Willie; Allton, Kathryn; Hallett, Steve

2014-05-01

The British Society for Soil Science (BSSS) http://www.soils.org.uk is an international membership organisation and UK based charity committed to promoting the study and profession of soil science in its widest aspects. The Society is committed to reaching out to the public at large to educate and inform on the importance of soils to us all. The Society has adopted a range of approaches to soil education, tailored to the needs and aims of different audience types. We have developed the 'Working with Soil' initiative http://www.soilscientist.org/workingwithsoil which provides practicing soil scientists and potential funders with a set of professional competencies aligned to specific aspects of work. From 2013 The Society has developed a program of courses aligned to these documents aimed at meeting the professional development needs of those undertaking such work. So far these have focused on fundamentals of field characterisation, sampling and mapping which have been very well received, especially by early career practitioners who have had less exposure to field work. We have also produced posters and leaflets that demonstrate a range of soil functions which support human society, for example 'Soils in the City' and 'Soils of Britain'. These were originally developed in a more traditional formal style. The materials have also proved popular with local authorities, regional horticultural clubs and higher education establishments, notably agricultural colleges where they have been used to support student learning in both timetabled and project work. We have subsequently produced a further set of materials aimed at a much younger audience. We deliberately chose slightly quirkier names for these, for example 'Soils and Time Travel' and 'Soils and Spaceship Earth' as a hook to capture the child's imagination. These were designed by a specialist company who used a less formal language, the use of cartoons and alternative images and a wider range of font styles and sizes

British Society of Interventional Radiology Iliac Artery Angioplasty-Stent Registry III

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uberoi, Raman, E-mail: raman.uberoi@orh.nhs.uk; Milburn, Simon; Moss, Jon

2009-09-15

The objective of this study was to audit current practice in iliac artery intervention in the United Kingdom. In 2001 the British Society of Interventional Radiology Iliac Artery Angioplasty-Stent (BIAS) III registry provided the first national database for iliac intervention. It recommended that data collection needed to continue in order to facilitate the dissemination of comparative data to individual units. BIAS III was designed to continue this work and has a simplified data set with an online submission form. Interventionalists were invited to complete a 3-page tick sheet for all iliac angioplasties and stents. Questions covered risk factors, procedural data,more » and outcome. Data for 2233 patients were submitted from 37 institutions over a 43-month period. Consultants performed 80% of the procedures, 62% of which were for claudication. Fifty-four percent of lesions were treated with stents and 25% of patients underwent bilateral intervention, resulting in a residual stenosis of <50% in 98%. Ninety-seven percent of procedures had no limb complication and there was a 98% inpatient survival rate. In conclusion, these figures provide an essential benchmark for both audit and patient information. National databases need to be expanded across the range of interventional procedures, and their collection made simple and, preferably, online.« less

British Society for Sexual Medicine Guidelines on Adult Testosterone Deficiency, With Statements for UK Practice.

PubMed

Hackett, Geoff; Kirby, Michael; Edwards, David; Jones, Thomas Hugh; Wylie, Kevan; Ossei-Gerning, Nick; David, Janine; Muneer, Asif

2017-12-01

Testosterone deficiency (TD) is an increasingly common problem with significant health implications, but its diagnosis and management can be challenging. To review the available literature on TD and provide evidence-based statements for UK clinical practice. Evidence was derived from Medline, EMBASE, and Cochrane searches on hypogonadism, testosterone (T) therapy, and cardiovascular safety from May 2005 to May 2015. Further searches continued until May 2017. To provide a guideline on diagnosing and managing TD, with levels of evidence and grades of recommendation, based on a critical review of the literature and consensus of the British Society of Sexual Medicine panel. 25 statements are provided, relating to 5 key areas: screening, diagnosis, initiating T therapy, benefits and risks of T therapy, and follow-up. 7 statements are supported by level 1, 8 by level 2, 5 by level 3, and 5 by level 4 evidence. To help guide UK practitioners on effectively diagnosing and managing primary and age-related TD. A large amount of literature was carefully sourced and reviewed, presenting the best evidence available at the time. However, some statements provided are based on poor-quality evidence. This is a rapidly evolving area of research and recommendations are subject to change. Guidelines can never replace clinical expertise when making treatment decisions for individual patients, but rather help to focus decisions and take personal values and preferences and individual circumstances into account. Many issues remain controversial, but in the meantime, clinicians need to manage patient needs and clinical expectations armed with the best clinical evidence and the multidisciplinary expert opinion available. Improving the diagnosis and management of TD in adult men should provide somatic, sexual, and psychological benefits and subsequent improvements in quality of life. Hackett G, Kirby M, Edwards D, et al. British Society for Sexual Medicine Guidelines on Adult Testosterone

Improved mitral valve coaptation and reduced mitral valve annular size after percutaneous mitral valve repair (PMVR) using the MitraClip system.

PubMed

Patzelt, Johannes; Zhang, Yingying; Magunia, Harry; Ulrich, Miriam; Jorbenadze, Rezo; Droppa, Michal; Zhang, Wenzhong; Lausberg, Henning; Walker, Tobias; Rosenberger, Peter; Seizer, Peter; Gawaz, Meinrad; Langer, Harald F

2017-08-01

Improved mitral valve leaflet coaptation with consecutive reduction of mitral regurgitation (MR) is a central goal of percutaneous mitral valve repair (PMVR) with the MitraClip® system. As influences of PMVR on mitral valve geometry have been suggested before, we examined the effect of the procedure on mitral annular size in relation to procedural outcome. Geometry of the mitral valve annulus was evaluated in 183 patients undergoing PMVR using echocardiography before and after the procedure and at follow-up. Mitral valve annular anterior-posterior (ap) diameter decreased from 34.0 ± 4.3 to 31.3 ± 4.9 mm (P < 0.001), and medio-lateral (ml) diameter from 33.2 ± 4.8 to 32.4 ± 4.9 mm (P < 0.001). Accordingly, we observed an increase in MV leaflet coaptation after PMVR. The reduction of mitral valve ap diameter showed a significant inverse correlation with residual MR. Importantly, the reduction of mitral valve ap diameter persisted at follow-up (31.3 ± 4.9 mm post PMVR, 28.4 ± 5.3 mm at follow-up). This study demonstrates mechanical approximation of both mitral valve annulus edges with improved mitral valve annular coaptation by PMVR using the MitraClip® system, which correlates with residual MR in patients with MR. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

Management of gout by UK rheumatologists: a British Society for Rheumatology national audit.

PubMed

Roddy, Edward; Packham, Jon; Obrenovic, Karen; Rivett, Ali; Ledingham, Joanna M

2018-05-01

To assess the concordance of gout management by UK rheumatologists with evidence-based best-practice recommendations. Data were collected on patients newly referred to UK rheumatology out-patient departments over an 8-week period. Baseline data included demographics, method of diagnosis, clinical features, comorbidities, urate-lowering therapy (ULT), prophylaxis and blood tests. Twelve months later, the most recent serum uric acid level was collected. Management was compared with audit standards derived from the 2006 EULAR recommendations, 2007 British Society for Rheumatology/British Health Professionals in Rheumatology guideline and the National Institute for Health and Care Excellence febuxostat technology appraisal. Data were collected for 434 patients from 91 rheumatology departments (mean age 59.8 years, 82% male). Diagnosis was crystal-proven in 13%. Of 106 taking a diuretic, this was reduced/stopped in 29%. ULT was continued/initiated in 76% of those with one or more indication for ULT. One hundred and fifty-eight patients started allopurinol: the starting dose was most commonly 100 mg daily (82%); in those with estimated glomerular filtration rate <60 ml/min the highest starting dose was 100 mg daily. Of 199 who started ULT, prophylaxis was co-prescribed for 94%. Fifty patients started a uricosuric or febuxostat: 84% had taken allopurinol previously. Of 44 commenced on febuxostat, 18% had a history of heart disease. By 12 months, serum uric acid levels ⩽360 and <300 μmol/l were achieved by 45 and 25%, respectively. Gout management by UK rheumatologists concords well with guidelines for most audit standards. However, fewer than half of patients achieved a target serum uric level over 12 months. Rheumatologists should help ensure that ULT is optimized to achieve target serum uric acid levels to benefit patients.

Highlights from the British Society for Heart Failure 20th Annual Autumn Meeting: three decades of heart failure.

PubMed

Abel, Alexandra AI

2018-05-16

The 20th Annual Autumn Meeting of the British Society for Heart Failure took place on the 23-24 November 2017 at the Queen Elizabeth II Conference Centre, London, UK. Over 800 delegates were in attendance: a multidisciplinary league of professionals who treat patients with heart failure, including specialist nurses, trainees, cardiologists, geriatricians, pharmacists and general practitioners. The theme of the conference was 'three decades of heart failure' and celebrated the success of modern heart failure management. This report highlights the 'three decades' session, the clinical trials update, and the main discussion points from heart failure question time.

Clinical management and outcome of refractory asthma in the UK from the British Thoracic Society Difficult Asthma Registry.

PubMed

Sweeney, Joan; Brightling, Chris E; Menzies-Gow, Andrew; Niven, Robert; Patterson, Chris C; Heaney, Liam G

2012-08-01

Refractory asthma represents a significant unmet clinical need. Data from a national online registry audited clinical outcome in 349 adults with refractory asthma from four UK specialist centres in the British Thoracic Society Difficult Asthma Network. At follow-up, lung function improved, with a reduction in important healthcare outcomes, specifically hospital admission, unscheduled healthcare visits and rescue courses of oral steroids. The most frequent therapeutic intervention was maintenance oral corticosteroids and most steroid sparing agents (apart from omalizumab) demonstrated minimal steroid sparing benefit. A significant unmet clinical need remains in this group, specifically a requirement for therapies which reduce systemic steroid exposure.

J.G. Crowther's War: Institutional strife at the BBC and British Council.

PubMed

Jones, Allan

2016-06-01

Science writer, historian and administrator J.G. Crowther (1899-1983) had an uneasy relationship with the BBC during the 1920s and 1930s, and was regarded with suspicion by the British security services because of his left politics. Nevertheless the Second World War saw him working for 'establishment' institutions. He was closely associated with the BBC's Overseas Service and employed by the British Council's Science Committee. Both organizations found Crowther useful because of his wide, international knowledge of science and scientists. Crowther's political views, and his international aspirations for the British Council's Science Committee, increasingly embroiled him in an institutional conflict with the Royal Society and with its president, Sir Henry Dale, who was also chairman of the British Council's Science Committee. The conflict centred on the management of international scientific relations, a matter close Crowther's heart, and to Dale's. Dale considered that the formal conduct of international scientific relations was the Royal Society's business rather than the British Council's. Crowther disagreed, and eventually resigned from the British Council Science Committee in 1946. The article expands knowledge of Crowther by drawing on archival documents to elucidate a side of his career that is only lightly touched on in his memoirs. It shows that 'Crowther's war' was also an institutional war between the Science Committee of the British Council and the Royal Society. Crowther's unhappy experience of interference by the Royal Society plausibly accounts for a retreat from his pre-war view that institutional science should plan and manage BBC science broadcasts.

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

Code of Federal Regulations, 2010 CFR

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 be...

Pregnancy-induced remodeling of heart valves.

PubMed

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. Copyright © 2015 the American Physiological Society.

Adults miscoded and misdiagnosed as having pneumonia: results from the British Thoracic Society pneumonia audit.

PubMed

Daniel, Priya; Bewick, Thomas; Welham, Sally; Mckeever, Tricia M; Lim, Wei Shen

2017-04-01

A key objective of the British Thoracic Society national community-acquired pneumonia (CAP) audit was to determine the clinical characteristics and outcomes of hospitalised adults given a primary discharge code of pneumonia but who did not fulfil accepted diagnostic criteria for pneumonia. Adults miscoded as having pneumonia (n=1251) were older compared with adults with CAP (n=6660) (median 80 vs 78 years, p<0.001) and had more comorbid disease, significantly fewer respiratory symptoms (fever, cough, dyspnoea, pleuritic pain), more constitutional symptoms (general deterioration, falls) and significantly lower 30-day inpatient mortality (14.3% vs 17.0%, adjusted OR 0.75, p=0.003). Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

British Thoracic Society guidelines for home oxygen use in adults.

PubMed

Hardinge, Maxine; Annandale, Joe; Bourne, Simon; Cooper, Brendan; Evans, Angela; Freeman, Daryl; Green, Angela; Hippolyte, Sabrine; Knowles, Vikki; MacNee, William; McDonnell, Lynn; Pye, Kathy; Suntharalingam, Jay; Vora, Vandana; Wilkinson, Tom

2015-06-01

The British Thoracic Society (BTS) Home Oxygen Guideline provides detailed evidence-based guidance for the use of home oxygen for patients out of hospital. Although the majority of evidence comes from the use of oxygen in patients with chronic obstructive pulmonary disease, the scope of the guidance includes patients with a variety of long-term respiratory illnesses and other groups in whom oxygen is currently ordered, such as those with cardiac failure, cancer and end-stage cardiorespiratory disease, terminal illness or cluster headache. It explores the evidence base for the use of different modalities of oxygen therapy and patient-related outcomes such as mortality, symptoms and quality of life. The guideline also makes recommendations for assessment and follow-up protocols, and risk assessments, particularly in the clinically challenging area of home oxygen users who smoke. The guideline development group is aware of the potential for confusion sometimes caused by the current nomenclature for different types of home oxygen, and rather than renaming them, has adopted the approach of clarifying those definitions, and in particular emphasising what is meant by long-term oxygen therapy and palliative oxygen therapy. The home oxygen guideline provides expert consensus opinion in areas where clinical evidence is lacking, and seeks to deliver improved prescribing practice, leading to improved compliance and improved patient outcomes, with consequent increased value to the health service. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

British Society of Paediatric Dentistry: a policy document on consent and the use of physical intervention in the dental care of children.

PubMed

Nunn, June; Foster, Martin; Master, Selina; Greening, Sue

2008-11-01

This policy document was prepared by J Nunn, M Foster, S Master and S Greening on behalf of the British Society of Paediatric Dentistry (BSPD). Policy documents produced by the BSPD represent a majority view, based on a consideration of currently available evidence. They are produced to provide guidance with the intention that the policy be regularly reviewed and updated to take account of changing views and developments.

Association of Tricuspid Regurgitation With Transcatheter Aortic Valve Replacement Outcomes: A Report From The Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry.

PubMed

McCarthy, Fenton H; Vemulapalli, Sreekanth; Li, Zhuokai; Thourani, Vinod; Matsouaka, Roland A; Desai, Nimesh D; Kirtane, Ajay; Anwaruddin, Saif; Williams, Matthew L; Giri, Jay; Vallabhajosyula, Prashanth; Li, Robert H; Herrmann, Howard C; Bavaria, Joseph E; Szeto, Wilson Y

2018-04-01

The purpose of this study is to evaluate the association of tricuspid regurgitation (TR) severity with outcomes after transcatheter aortic valve replacement (TAVR). We analyzed data from 34,576 patients who underwent TAVR at 365 US hospitals from November 2011 through March 2015 submitted to The Society of Thoracic Surgeon/American College of Cardiology Transcatheter Valve Therapy Registry. We examined unadjusted mortality and heart failure readmission stratified by degree of preoperative TR and used multivariable models for 1-year mortality and heart failure readmission. Tricuspid regurgitation was present in 80% (n = 27,804) of TAVR patients, with mild TR in 56% (n = 19,393), moderate TR in 19% (n = 6687), and severe TR in 5% (n = 1,724). Increasing TR severity was associated with a number of comorbidities and The Society of Thoracic Surgeons predicted risk of mortality increased (p < 0.001): no TR (7.3 ± 5.4); mild TR (8.0 ± 5.7); moderate TR (9.6 ± 6.8); and severe TR (10.7 ± 7.4). In unadjusted analysis, moderate and severe TR were associated with increased use of cardiopulmonary bypass, longer intensive care unit and hospital stays, new dialysis, inhospital major adverse cardiac event, inhospital mortality, observed-to-expected inhospital mortality ratio, long-term heart failure readmission, and mortality (p < 0.001). Adjusted mortality at 1 year was significantly worse for patients with severe TR when left ventricular ejection fraction greater than 30% (hazard ratio 1.29, 95% confidence interval: 1.11 to 1.50) as was heart failure readmission (hazard ratio 1.27, 95% confidence interval: 1.04 to 1.54). Tricuspid regurgitation was common among patients undergoing TAVR. Increasing TR severity was associated with higher risk patients and increased mortality and readmission-particularly for patients with severe TR and left ventricular ejection fraction greater than 30%. The effectiveness of TAVR alone in patients with aortic stenosis and concomitant

Long-term outcome in dogs undergoing mitral valve repair with suture annuloplasty and chordae tendinae replacement.

PubMed

Mizuno, T; Mizukoshi, T; Uechi, M

2013-02-01

Mitral valve repair under cardiopulmonary bypass was performed in three dogs with clinical signs associated with mitral regurgitation that were not controlled by medication. Mitral valve repair comprised circumferential annuloplasty and chordal replacement with expanded polytetrafluoroethylene. One dog died 2 years after surgery because of severe mitral regurgitation resulting from partial circumferential suture detachment. The others survived for over 5 years, but mild mitral valve stenosis persisted in one. The replaced chordae did not rupture in any dog. Mitral valve repair appears to be an effective treatment for mitral regurgitation in dogs. Chordal replacement with expanded polytetrafluoroethylene is a feasible technique, demonstrating long-term durability in dogs. However, mitral annuloplasty techniques need improvement. © 2012 British Small Animal Veterinary Association.

Leaving Moderate Tricuspid Valve Regurgitation Alone at the Time of Pulmonary Valve Replacement: A Worthwhile Approach.

PubMed

Kogon, Brian; Mori, Makoto; Alsoufi, Bahaaldin; Kanter, Kirk; Oster, Matt

2015-06-01

regurgitation, significant improvement in tricuspid valve function and right ventricular size occurs in the first postoperative month after pulmonary valve replacement, irrespective of concomitant tricuspid valve annuloplasty. The tricuspid valve appears to function better over the midterm if annuloplasty is not performed. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

British Society of Interventional Radiology: Biliary Drainage and Stenting Registry (BDSR)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uberoi, R., E-mail: raman.uberoi@orh.nhs.uk; Das, N.; Moss, J.

Objectives: This study was designed to audit current practice in percutaneous biliary drainage and stenting in the United Kingdom. Methods: In 2006, the British Society of Interventional Radiology set up the first web-based Biliary Drainage and Stenting Registry (BDSR). This consisted of a series of tick sheets, which were completed online. Data collection included technical and clinical success of the procedures and outcomes at discharge with a separate form for any follow-up visits. Two months before data analysis, all contributors were asked via email to complete any outstanding data. This paper reports on data collected between November 1, 2006 andmore » August 18, 2009. Results: A total of 833 procedures were recorded and were entered by 62 operators from 44 institutions within the United Kingdom. There were 455 men and 378 women with a median age of 69 (range 20-101) years.The majority of procedures were performed by a consultant. Successful drainage of the biliary tree was achieved in 98.7%. Partial or complete relief of symptoms was seen in 65% of patients. Minor complications, predominantly pain (14.3%), were seen in 26% and major complications, predominantly sepsis (3.5%), were seen in 7.9% of patients. Conclusions: These figures provide an essential benchmark for both audit and patient information. Identifying areas of good practice and those that require improvement will ultimately result in better patient care.« less

Inflammatory bowel disease biopsies: updated British Society of Gastroenterology reporting guidelines.

PubMed

Feakins, Roger M

2013-12-01

Accurate histopathological assessment of biopsies is important for the diagnosis, subclassification, and management of chronic idiopathic inflammatory bowel disease (IBD). British Society of Gastroenterology (BSG) guidelines for the initial histopathological diagnosis of IBD were published in 1997. Changes since then include: more widespread use of full colonoscopy; greater recognition of the effects of time and treatment; improved documentation of variations in anatomical distribution; better understanding of the mimics of IBD; significant progress in clinical management; and modifications of terminology. Accordingly, an update is required. These revised guidelines aim to optimise the quality and consistency of reporting of biopsies taken for the initial diagnosis of IBD by summarising the literature and making recommendations based on the available evidence. Advice from existing clinical guidelines is also taken into account. Among the subjects discussed are: distinguishing IBD from other colitides, particularly infective colitis; subclassification of IBD (as ulcerative colitis, Crohn's disease, or IBD unclassified); the discriminant value of granulomas; aspects of disease distribution, including discontinuity in ulcerative colitis; time-related changes; differences between paediatric and adult IBD; the role of ileal and upper gastrointestinal biopsies; differential diagnoses such as diverticular colitis and diversion proctocolitis; and dysplasia. The need to correlate the histological features with clinical and endoscopic findings is emphasised. An approach to the conclusion of an IBD biopsy report based on the acronym Pattern, Activity, Interpretation, Dysplasia (PAID) is suggested. The key recommendations are listed at the end of the document.

A brief history of the British Pharmacological Society

PubMed Central

Cuthbert, Alan W

2006-01-01

The article traces the history of the BPS since its inception in 1931 until the present day. Details are given about the size and nature of the membership and how the governance of the Society has changed during the last 75 years. The emergence of the Clinical Section from within the main Society and the growth of the Society's publications are described. PMID:16402105

Prosthetic valve endocarditis 7 months after transcatheter aortic valve implantation diagnosed with 3D TEE.

PubMed

Sarı, Cenk; Durmaz, Tahir; Karaduman, Bilge Duran; Keleş, Telat; Bayram, Hüseyin; Baştuğ, Serdal; Özen, Mehmet Burak; Bayram, Nihal Akar; Bilen, Emine; Ayhan, Hüseyin; Kasapkara, Hacı Ahmet; Bozkurt, Engin

2016-01-01

Transcatheter aortic valve implantation (TAVI) was introduced as an alternative treatment for patients with severe symptomatic aortic stenosis for whom surgery would be high-risk. Prosthetic aortic valve endocarditis is a serious complication of surgical AVR (SAVR) with high morbidity and mortality. According to recent cases, post-TAVI prosthetic valve endocarditis (PVE) seems to occur very rarely. We present the case of a 75-year-old woman who underwent TAVI (Edwards Saphien XT) with an uneventful postoperative stay. She was diagnosed with endocarditis using three dimensional (3D) echocardiography on the TAVI device 7 months later and she subsequently underwent surgical aortic valve replacement. Little experience of the interpretation of transoesophageal echocardiography (TEE) and the clinical course and effectiveness of treatment strategies in post-TAVI endocarditis exists. We report a case of PVE in a TAVI patient which was diagnosed with three-dimensional transoesophageal echocardiography (3DTEE). Copyright © 2016 Hellenic Cardiological Society. Published by Elsevier B.V. All rights reserved.

Afebrile Pannus-Induced Blood Culture-Negative Mechanical Valve Endocarditis.

PubMed

Matsukuma, Seiji; Eishi, Kiyoyuki; Tanigawa, Kazuyoshi; Miura, Takashi; Matsumaru, Ichiro; Hisatomi, Kazuki; Tsuneto, Akira

2016-12-01

The diagnosis of prosthetic valve endocarditis may be challenging in patients with an atypical clinical presentation. Virtually all infections associated with mechanical prosthetic valves are localized to the prosthesis-tissue junction at the sewing ring and are accompanied by tissue destruction around the prosthesis. Because the orifice of the mechanical prosthetic valve is made of metal and pyrolytic carbon, which do not enable the adherence of microorganisms, any vegetation originating from the interior of the valve orifice is usually rare. Here we present a rare case of pannus-induced mechanical prosthetic valve endocarditis that was difficult to diagnose. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Bioprosthetic Aortic Valve Durability: A Meta-Regression of Published Studies.

PubMed

Wang, Mansen; Furnary, Anthony P; Li, Hsin-Fang; Grunkemeier, Gary L

2017-09-01

To compare structural valve deterioration (SVD) among bioprosthetic aortic valve types, a PubMed search found 54 papers containing SVD-free curves extending to at least 10 years. The curves were digitized and fit to Weibull distributions, and the mean times to valve failure (MTTF) were calculated. Twelve valve models were collapsed into four valve types: Medtronic (Medtronic, Minneapolis, MN) and Edwards (Edwards Lifesciences, Irvine, CA) porcine; and Sorin (Sorin Group [now LivaNova], London, United Kingdom) and Edwards pericardial. Meta-regression found MTTF was associated with the patient's age, publication year, SVD definition, and valve type. Sorin pericardial valves had significantly lower risk-adjusted MTTF (higher SVD risk), and there were no significant differences in MTTF among the other three valve types. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Loss of Axin2 results in impaired heart valve maturation and subsequent myxomatous valve disease.

PubMed

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.

Validation of the Pangao PG-800A11 wrist device assessed according to the European Society of Hypertension and the British Hypertension Society protocols.

PubMed

Xie, Peigen; Wang, Yanling; Xu, Xiaoying; Huang, Fei; Pan, Jingru

2015-04-01

The objective of this study was to determine the accuracy of the Pangao PG-800A11 wrist blood pressure monitor according to the European Society of Hypertension International Protocol (ESH-IP) revision 2010 and the protocol of the British Hypertension Society (BHS). The device evaluations were performed in 85 participants, 33 of whom were included according to the ESH-IP revision 2010 and 52 of whom were included on the basis of the requirements of the BHS protocol. The validation procedure and data analysis followed the protocols precisely. The device achieved an A/A grading for the BHS protocol and passed all phases of the ESH-IP revision 2010 protocol. The mean difference ±SD for the ESH and BHS protocols, respectively, was -0.6±4.5 and -0.8±6.2 mmHg for systolic pressure and 1.2±4.6 and -0.5±5.1 mmHg for diastolic pressure. The device maintained its A/A grading throughout the low, medium, and high-pressure ranges. The Pangao PG-800A11 wrist blood pressure monitor passed all requirements of the ESH-IP revision 2010 and achieved A/A grade of the BHS protocol in an adult population.

Quality and Safety in Health Care, Part XXIX: The Transcatheter Valve Therapy Registry.

PubMed

Harolds, Jay A

2017-11-01

The American College of Cardiology, the Society of Thoracic Surgeons, and other organizations cooperated to form the Transcatheter Valve Therapy Registry. This registry studies information on the outcome of valve therapy device placement with a transcatheter approach. The companies that manufacture these devices can use the registry to meet the post-product sale surveillance requirements of the US Food and Drug Administration. There will also be linkage to the registry information from the Society of Thoracic Surgeons Adult Cardiac Surgery Database, which has information on open cardiac valve surgery.

Surgeon Involvement in Transcatheter Aortic Valve Replacement in the United States: A 2016 Society of Thoracic Surgeons Survey.

PubMed

Bavaria, Joseph E; Prager, Richard L; Naunheim, Keith S; Allen, Mark S; Higgins, Robert S D; Thourani, Vinod H; MacGillivray, Thomas E; Boden, Natalie; Sabik, Joseph F

2017-09-01

The Society of Thoracic Surgeons (STS) surveyed cardiothoracic surgeon participants in its Adult Cardiac Surgery Database (ACSD) to learn the extent of surgeon involvement in transcatheter aortic valve replacement (TAVR) procedures. An electronic survey was delivered to 2,594 surgeons in June 2016. When the survey closed 2 weeks later, 487 completed surveys had been submitted for a response rate of 18.8%. Among the 487 participants in the ACSD who responded to the survey, 410 (84.2%) reported that TAVR was performed at their institutions. Approximately three-quarters reported that they performed TAVR procedures as part of a heart team (77.5%; 313 of 404), cardiologists and cardiothoracic surgeons were jointly responsible for TAVR referrals (83.7%; 339 of 405), and TAVR programs were administered either jointly by the cardiology and cardiac surgery departments or exclusively by the cardiac surgery department (73.3%; 297 of 405). A majority were involved in the pre-, intra-, and postoperative care of patients undergoing TAVR, with 91.4% (370 of 405) reporting participation in multidisciplinary meetings, at least 50% regularly performing technical aspects in 10 of 11 conduct of operation categories, and 86.6% (266 of 307) caring for patients undergoing TAVR after the procedure. Cardiac surgeons in the United States are active participants in the management of patients with aortic stenosis as part of the heart team. The STS survey found that not only were they actively involved in the treatment decision-making process but they also played a significant role in the valve procedure, including deployment and postprocedural care. The heart team model continues to evolve and should be expanded into other areas of structural heart disease. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Aortic biological valve thrombosis in an HIV positive patient.

PubMed

Achouh, Paul; Jemel, Amine; Chaudeurge, Aurélie; Redheuil, Alban; Zegdi, Rachid; Fabiani, Jean-Noël

2011-06-01

Biological aortic valve thrombosis is an exceptional complication. A 64-year-old patient positive for human immunodeficiency virus presented for syncope on exertion, 2 years after an aortic bioprosthetic valve replacement and double coronary artery bypass. Transvalvular aortic mean gradient was approximately 50 mm Hg on echocardiogram and catheterization. Cardiac computed tomography scan showed a limited opening of the bioprosthesis cusps. Surgical exploration revealed thrombosis of the three cusps on the aortic side, limiting the opening of the valve. No relation could be established between the patient's human immunodeficiency virus status and valve thrombosis. Copyright © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Aortic valve replacement for aortic stenosis caused by alkaptonuria.

PubMed

Hiroyoshi, Junko; Saito, Aya; Panthee, Nirmal; Imai, Yasushi; Kawashima, Dai; Motomura, Noboru; Ono, Minoru

2013-03-01

We report a case of aortic stenosis associated with ochronosis in a 70-year-old man who underwent biologic aortic valve replacement. Intraoperative findings included ochronosis of a severely calcified pigmented aortic valve along with pigmentation of the intima of the aorta. Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Bioprosthetic Valve Fracture Improves the Hemodynamic Results of Valve-in-Valve Transcatheter Aortic Valve Replacement.

PubMed

Chhatriwalla, Adnan K; Allen, Keith B; Saxon, John T; Cohen, David J; Aggarwal, Sanjeev; Hart, Anthony J; Baron, Suzanne J; Dvir, Danny; Borkon, A Michael

2017-07-01

Valve-in-valve (VIV) transcatheter aortic valve replacement (TAVR) may be less effective in small surgical valves because of patient/prosthesis mismatch. Bioprosthetic valve fracture (BVF) using a high-pressure balloon can be performed to facilitate VIV TAVR. We report data from 20 consecutive clinical cases in which BVF was successfully performed before or after VIV TAVR by inflation of a high-pressure balloon positioned across the valve ring during rapid ventricular pacing. Hemodynamic measurements and calculation of the valve effective orifice area were performed at baseline, immediately after VIV TAVR, and after BVF. BVF was successfully performed in 20 patients undergoing VIV TAVR with balloon-expandable (n=8) or self-expanding (n=12) transcatheter valves in Mitroflow, Carpentier-Edwards Perimount, Magna and Magna Ease, Biocor Epic and Biocor Epic Supra, and Mosaic surgical valves. Successful fracture was noted fluoroscopically when the waist of the balloon released and by a sudden drop in inflation pressure, often accompanied by an audible snap. BVF resulted in a reduction in the mean transvalvular gradient (from 20.5±7.4 to 6.7±3.7 mm Hg, P <0.001) and an increase in valve effective orifice area (from 1.0±0.4 to 1.8±0.6 cm 2 , P <0.001). No procedural complications were reported. BVF can be performed safely in small surgical valves to facilitate VIV TAVR with either balloon-expandable or self-expanding transcatheter valves and results in reduced residual transvalvular gradients and increased valve effective orifice area. © 2017 American Heart Association, Inc.

Delayed-onset streptococcus pyogenes endophthalmitis following Ahmed glaucoma valve implantation.

PubMed

Bayraktar, Zerrin; Kapran, Ziya; Bayraktar, Sükrü; Acar, Nur; Unver, Yaprak Banu; Gök, Kemran

2005-01-01

To report a case of delayed-onset Streptococcus pyogenes endophthalmitis following implantation of an Ahmed glaucoma valve. A 10-year-old patient presented with acute endophthalmitis 1 year after Ahmed glaucoma valve implantation. The conjunctiva and Tenon's capsule over the valve plate had been penetrated by one of the polypropylene fixation sutures. The valve was removed, and pars plana vitrectomy was performed. Vitreous specimens and removal of the discharge over the plate revealed Streptococcus pyogenes. This is the first documented case of Streptococcus pyogenes endophthalmitis following Ahmed glaucoma valve implantation. We think the conjunctival buttonhole caused by the polypropylene suture provided an entry site for the infection. (c) Japanese Ophthalmological Society 2005.

Transapical Mitral Valve Implantation for Native Mitral Valve Stenosis Using a Balloon-Expandable Prosthesis.

PubMed

Kiefer, Philipp; Noack, Thilo; Seeburger, Joerg; Hoyer, Alexandro; Linke, Axel; Mangner, Norman; Lehmkuhl, Lukas; Mohr, Friedrich Wilhelm; Holzhey, David

2017-12-01

Transcatheter mitral valve implantation (TMVI) is still in its infancy and is mainly limited to valve-in-valve or valve-in-ring implantations. We present the early experience with TMVI for severe calcified native MV stenosis. Between January 2014 and June 2015, 6 of 11 patients screened (mean age, 77.4 ± 6.3 years; 66% men) with severe native mitral valve (MV) stenosis (mean gradient [Pmean], 11.1 ± 2.1 mm Hg; mean effective orifice area [EOA], 0.9 ± 0.12 cm 2 ) underwent transcatheter MV replacement at our institution as a bailout procedure. Conventional surgical procedures were denied in all patients because of severe annular calcification and extensive comorbidities (mean logistic EuroScore, 31.4% ± 8.3%). The Edwards SAPIEN 3 (29 mm) (Edwards Lifesciences, Irvine, CA) was used in all cases. Procedural access was transapical in 5 cases and concomitant to aortic valve replacement through the left atrium through a sternotomy in 1 case. Initial implantation was successful in 100% of the cases. Because of early migration, 1 patient needed a valve-in-valve procedure. Postoperative echocardiography showed no residual mitral regurgitation in 4 cases (66%) and mild regurgitation in 2 cases (34%). Mean gradients were reduced to 4.2 ± 0.6 mm Hg (mean EOA, 2.8 ± 0.4 cm 2) . No patient had a stroke during hospitalization, and 30-day mortality was seen in 1 patient (17%) resulting from pneumonia. TMV implantation using the SAPIEN 3 aortic prosthesis in patients with heavy annular calcification is feasible and represents a reasonable bailout option for inoperable patients. However, several limitations need to be considered in this special patient population. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Cognitive development: no stages please--we're British.

PubMed

Goswami, U

2001-02-01

British cognitive developmental psychology is characterized by its interest in philosophical questions, its preference for linking basic research to applied issues in education and cognitive disorders, and its willingness to learn both methodologically and theoretically from work in animal psychology and in physiology more generally. It has also been influenced profoundly by Jean Piaget's cognitive stage theory although in general British work has focused on demonstrating early strengths, rather than early deficits, in infant and child cognition. Following an overview of British work that encompasses past and present interests, issues and challenges for the future are highlighted. While the perspectives of the founding members of the British Psychological Society (BPS), as outlined by Edgell (1947), are still apparent in British research in cognitive developmental psychology today, it is argued that future cognitive work must become even more interdisciplinary and that the symbiotic relationship between research in adult cognition and in cognitive development needs greater recognition.

Cognitive development: No stages please - we're British.

PubMed

Goswami, Usha

2001-02-01

British cognitive developmental psychology is characterized by its interest in philosophical questions, its preference for linking basic research to applied issues in education and cognitive disorders, and its willingness to learn both methodologically and theoretically from work in animal psychology and in physiology more generally. It has also been influenced profoundly by Jean Piaget's cognitive stage theory although in general British work has focused on demonstrating early strengths, rather than early deficits, in infant and child cognition. Following an overview of British work that encompasses past and present interests, issues and challenges for the future are highlighted. While the perspectives of the founding members of the British Psychological Society (BPS), as outlined by Edgell (1947), are still apparent in British research in cognitive developmental psychology today, it is argued that future cognitive work must become even more interdisciplinary and that the symbiotic relationship between research in adult cognition and in cognitive development needs greater recognition.

Evolving Indications for Tricuspid Valve Surgery

PubMed Central

Sales, Virna L.

2010-01-01

Opinion statement More attention has been paid to the mitral valve (MV) than the tricuspid valve (TV), and this relative paucity of data has led to confusion regarding the timing of TV surgery. We review the American College of Cardiology/American Heart Association and European Society of Cardiology guidelines to identify areas of concordance (severe tricuspid regurgitation [TR] in a patient undergoing mitral valve surgery); discordance (less than severe TR but with markers for late TR recurrence such as pulmonary hypertension, a dilated TV annulus, atrial fibrillation, permanent transtricuspid pacing wires and others); and disagreement (surgery for primary TR). We provide our perspective from Northwestern University on these issues and where the guidelines are silent (TR in patients undergoing non-mitral valve operations). Finally, we review recent publications on the results of TV repair and replacement. Although there have been scant publications in the past, there have been more useful publications in recent years to guide our decision making. PMID:21063935

Transcatheter Aortic Valve-in-Valve Procedure in Patients with Bioprosthetic Structural Valve Deterioration

PubMed Central

Reul, Ross M.; Ramchandani, Mahesh K.; Reardon, Michael J.

2017-01-01

Surgical aortic valve replacement is the gold standard procedure to treat patients with severe, symptomatic aortic valve stenosis or insufficiency. Bioprosthetic valves are used for surgical aortic valve replacement with a much greater prevalence than mechanical valves. However, bioprosthetic valves may fail over time because of structural valve deterioration; this often requires intervention due to severe bioprosthetic valve stenosis or regurgitation or a combination of both. In select patients, transcatheter aortic valve replacement is an alternative to surgical aortic valve replacement. Transcatheter valve-in-valve (ViV) replacement is performed by implanting a transcatheter heart valve within a failing bioprosthetic valve. The transcatheter ViV operation is a less invasive procedure compared with reoperative surgical aortic valve replacement, but it has been associated with specific complications and requires extensive preoperative work-up and planning by the heart team. Data from experimental studies and analyses of results from clinical procedures have led to strategies to improve outcomes of these procedures. The type, size, and implant position of the transcatheter valve can be optimized for individual patients with knowledge of detailed dimensions of the surgical valve and radiographic and echocardiographic measurements of the patient's anatomy. Understanding the complexities of the ViV procedure can lead surgeons to make choices during the original surgical valve implantation that can make a future ViV operation more technically feasible years before it is required. PMID:29743998

A Simple Device for Morphofunctional Evaluation During Aortic Valve-Sparing Surgery.

PubMed

Leone, Alessandro; Bruno, Piergiorgio; Cammertoni, Federico; Massetti, Massimo

2015-07-01

Valve-sparing operations for the treatment of aortic root disease with a structurally normal aortic valve are increasingly performed as they avoid prosthesis-related complications. Short- and long-term results are critically dependent on perfect intraoperative restoration of valve anatomy and function. Residual aortic regurgitation is the main cause of early failure, and it is the most common motive for reoperation. However, intraoperative morphofunctional valve assessment requires expertise, and only transesophageal echocardiography can provide reliable information. We describe a simple, economic, reproducible hydrostatic test to intraoperatively evaluate valve competency under direct visualization. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Aortic valve function after bicuspidization of the unicuspid aortic valve.

PubMed

Aicher, Diana; Bewarder, Moritz; Kindermann, Michael; Abdul-Khalique, Hashim; Schäfers, Hans-Joachim

2013-05-01

Unicuspid aortic valve (UAV) anatomy leads to dysfunction of the valve in young individuals. We introduced a reconstructive technique of bicuspidizing the UAV. Initially we copied the typical asymmetry of a normal bicuspid aortic valve (BAV) (I), later we created a symmetric BAV (II). This study compared the hemodynamic function of the two designs of a bicuspidized UAV. Aortic valve function was studied at rest and during exercise in 28 patients after repair of UAV (group I, n = 8; group II, n = 20). There were no differences among the groups I and II with respect to gender, age, body size, or weight. All patients were in New York Heart Association class I. Six healthy adults served as control individuals. All patients were studied with transthoracic echocardiography between 4 and 65 months postoperatively. Systolic gradients were assessed by continuous wave Doppler while patients were at rest and exercising on a bicycle ergometer. Aortic regurgitation was grade I or less in all patients. Resting gradients were significantly elevated in group I compared with group II and control individuals (group I, peak 33.8 ± 7.8 mm Hg; mean 19.1 ± 5.4 mm Hg; group II, peak 15.8 ± 5.4, mean 8.2 ± 2.8 mm Hg; control individuals, peak 6.0 ± 1.6, mean 3.2 ± 0.8 mm Hg; p < 0.001). At 100 W peak gradients were highest in group I (group I, 62.7 ± 16.7 mm Hg; group II, 28.1 ± 7.6 mm Hg; control individuals, 15.4 ± 4.6 mm Hg; p < 0.001). Converting a UAV into a symmetric bicuspid design results in adequate valve competence. A symmetric repair design leads to improved systolic aortic valve function at rest and during exercise. Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Relationship between the logistic EuroSCORE and the Society of Thoracic Surgeons Predicted Risk of Mortality score in patients implanted with the CoreValve ReValving system--a Bern-Rotterdam Study.

PubMed

Piazza, Nicolo; Wenaweser, Peter; van Gameren, Menno; Pilgrim, Thomas; Tzikas, Apostolos; Tsikas, Apostolos; Otten, Amber; Nuis, Rutger; Onuma, Yoshinobu; Cheng, Jin Ming; Kappetein, A Pieter; Boersma, Eric; Juni, Peter; de Jaegere, Peter; Windecker, Stephan; Serruys, Patrick W

2010-02-01

Surgical risk scores, such as the logistic EuroSCORE (LES) and Society of Thoracic Surgeons Predicted Risk of Mortality (STS) score, are commonly used to identify high-risk or "inoperable" patients for transcatheter aortic valve implantation (TAVI). In Europe, the LES plays an important role in selecting patients for implantation with the Medtronic CoreValve System. What is less clear, however, is the role of the STS score of these patients and the relationship between the LES and STS. The purpose of this study is to examine the correlation between LES and STS scores and their performance characteristics in high-risk surgical patients implanted with the Medtronic CoreValve System. All consecutive patients (n = 168) in whom a CoreValve bioprosthesis was implanted between November 2005 and June 2009 at 2 centers (Bern University Hospital, Bern, Switzerland, and Erasmus Medical Center, Rotterdam, The Netherlands) were included for analysis. Patient demographics were recorded in a prospective database. Logistic EuroSCORE and STS scores were calculated on a prospective and retrospective basis, respectively. Observed mortality was 11.1%. The mean LES was 3 times higher than the mean STS score (LES 20.2% +/- 13.9% vs STS 6.7% +/- 5.8%). Based on the various LES and STS cutoff values used in previous and ongoing TAVI trials, 53% of patients had an LES > or =15%, 16% had an STS > or =10%, and 40% had an LES > or =20% or STS > or =10%. Pearson correlation coefficient revealed a reasonable (moderate) linear relationship between the LES and STS scores, r = 0.58, P < .001. Although the STS score outperformed the LES, both models had suboptimal discriminatory power (c-statistic, 0.49 for LES and 0.69 for STS) and calibration. Clinical judgment and the Heart Team concept should play a key role in selecting patients for TAVI, whereas currently available surgical risk score algorithms should be used to guide clinical decision making. Copyright (c) 2010 Mosby, Inc. All rights

Diagnosis and management of hymenoptera venom allergy: British Society for Allergy and Clinical Immunology (BSACI) guidelines.

PubMed

Krishna, M T; Ewan, P W; Diwakar, L; Durham, S R; Frew, A J; Leech, S C; Nasser, S M

2011-09-01

This guidance for the management of patients with hymenoptera venom allergy has been prepared by the Standards of Care Committee (SOCC) of the British Society for Allergy and Clinical Immunology (BSACI). The guideline is based on evidence as well as on expert opinion and is for use by both adult physicians and pediatricians practising allergy. During the development of these guidelines, all BSACI members were included in the consultation process using a web-based system. Their comments and suggestions were carefully considered by the SOCC. Where evidence was lacking, consensus was reached by the experts on the committee. Included in this guideline are epidemiology, risk factors, clinical features, diagnostic tests, natural history of hymenoptera venom allergy and guidance on undertaking venom immunotherapy (VIT). There are also separate sections on children, elevated baseline tryptase and mastocytosis and mechanisms underlying VIT. Finally, we have made recommendations for potential areas of future research. © 2011 Blackwell Publishing Ltd.

Recommendations for the imaging assessment of prosthetic heart valves: a report from the European Association of Cardiovascular Imaging endorsed by the Chinese Society of Echocardiography, the Inter-American Society of Echocardiography, and the Brazilian Department of Cardiovascular Imaging.

PubMed

Lancellotti, Patrizio; Pibarot, Philippe; Chambers, John; Edvardsen, Thor; Delgado, Victoria; Dulgheru, Raluca; Pepi, Mauro; Cosyns, Bernard; Dweck, Mark R; Garbi, Madalina; Magne, Julien; Nieman, Koen; Rosenhek, Raphael; Bernard, Anne; Lowenstein, Jorge; Vieira, Marcelo Luiz Campos; Rabischoffsky, Arnaldo; Vyhmeister, Rodrigo Hernández; Zhou, Xiao; Zhang, Yun; Zamorano, Jose-Luis; Habib, Gilbert

2016-06-01

Prosthetic heart valve (PHV) dysfunction is rare but potentially life-threatening. Although often challenging, establishing the exact cause of PHV dysfunction is essential to determine the appropriate treatment strategy. In clinical practice, a comprehensive approach that integrates several parameters of valve morphology and function assessed with 2D/3D transthoracic and transoesophageal echocardiography is a key to appropriately detect and quantitate PHV dysfunction. Cinefluoroscopy, multidetector computed tomography, cardiac magnetic resonance imaging, and to a lesser extent, nuclear imaging are complementary tools for the diagnosis and management of PHV complications. The present document provides recommendations for the use of multimodality imaging in the assessment of PHVs. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

Conservative management of CIN2: National Audit of British Society for Colposcopy and Cervical Pathology members' opinion.

PubMed

Macdonald, Madeleine; Smith, John H F; Tidy, John A; Palmer, Julia E

2018-04-01

There is no doubt that organised cervical screening programmes have significantly reduced the rates of cervical cancer by detection and treatment of high-grade cervical intraepithelial neoplasia (CIN2, CIN3). National UK guidelines do not differentiate between CIN2 and CIN3 as separate entities and recommend treatment for both, although a degree of uncertainty exists regarding the natural history of CIN2. This national survey of British Society for Colposcopy and Cervical Pathology members aimed to assess attitudes towards conservative management (CM) of CIN2 in the UK and identify potential selection criteria. In total, 511 members responded (response rate 32%); 55.6% offered CM for selective cases; 12.4% for all cases; 16.4% had formal guidelines. Most agreed age group was >40yrs (83%), HPV 16/18 positive (51.4%), smoking (60%), immuno-compromise (74.2%), and large lesion size (80.8%) were relative contraindications for CM. 75.9% favoured six-monthly monitoring, with 80.2% preferring excisional treatment for persistent high-grade disease. Many UK colposcopists manage CIN2 conservatively without formal guidelines. Potential selection criteria should be investigated by a multicentre study. Impact statement Although anecdotally some colposcopists manage many women with CIN2 conservatively, this National Audit of British Society for Colposcopy and Cytopathology members, we believe, is the first time this has been formally recorded. The survey assesses current attitudes towards conservative management (CM) of CIN2 and seeks to identify potential selection criteria that could be used to identify suitable women. It received over 500 responses and significantly, identified many colposcopists recommending CM of CIN2 for patients despite the lack of any formal guidance regarding this approach. The greater majority of respondents were keen to consider participating in a multicentre trial on CM of CIN2 targeting the UK screening population (25-64 years). The paper has

British anti-vaccination propaganda.

PubMed

Vandervelde, V D

1974-10-01

In April 1972, "Postal History International" published an article of mine concerning anti-vaccination caricature envelopes, which has led to some correspondence with readers and the discovery of several related items. It seems appropriate, therefore, to summarise the information in these pages, in the hope that this may bring forth knowledgeable comment from others. Details of any foreign propaganda of this sort would be particularly welcome. Meanwhile, this articles summarises what is known of the Society responsible for at least some of the British envelopes, and fills in a little of the historical background. The assistance of Mr. Ritchie Bodily is gratefully acknowledged, while the historical information was culled from the Newspaper Library of the British Museum at Colindale. Certain errors in the initial article can now be corrected, notably as to the name and location of the "persecuted man of Truth".

Summary of the British Transplantation Society UK Guidelines for Living Donor Liver Transplantation.

PubMed

Manas, Derek; Burnapp, Lisa; Andrews, Peter Antony

2016-06-01

The British Transplantation Society Guidelines for Living Donor Liver Transplantation was published in July 2015 and is the first national guideline in the field of living donor liver transplantation. The guideline aims to review the evidence relating to the evaluation process of both recipient and donor candidates; address the moral and ethical issues surrounding the procedure; outline the technical aspects of the procedure, including the middle hepatic vein controversy and the "small for size syndrome"; review donor and recipient outcomes and complications including donor mortality; and examine evidence relating to the advantages and disadvantages of living donor liver transplantation. In line with previous guidelines published by the BTS, the guideline has used the Grading of Recommendations Assessment, Development and Evaluation system to rate the strength of evidence and recommendations. This article summarizes the Statements of Recommendation contained in the guideline, which provide a framework for the delivery of living liver donation in the United Kingdom and may be of wide international interest. It is recommended that the full guideline document is consulted for details of the relevant references and evidence base. This may be accessed at http://www.bts.org.uk/BTS/Guidelines_Standards/Current/BTS/Guidelines_Standards/Current_Guidelines.aspx?hkey=e285ca32-5920-4613-ac08-fa9fd90915b5.

Pelvic pain: a pathway for care developed for both men and women by the British Pain Society.

PubMed

Baranowski, A P; Lee, J; Price, C; Hughes, J

2014-03-01

This paper aims to explain the key points and highlight some of the controversies in the development of the British Pain Society's pelvic pain patient pathway map. Many clinicians lack experience and confidence with this group of patients, and this issue is highlighted. Additionally, the difficulties of classification and definitions in this area are discussed in detail. These are historical causes of disagreement among specialists which can lead to confused clinical care. This group of patients have multiple issues that cross many professional boundaries; they are best managed by the co-ordinated involvement of multiple teams. Patients suffer from significant distress and disability that often needs specialist assessment and intervention (interdisciplinary). This suggests that an integrated approach is required across the historic boundaries of primary and secondary care. A variety of interventions, including opioids and neuromodulation are recommended in the pathway and the controversies surrounding these inclusions are aired in detail.

Transcatheter aortic valve-in-valve implantation of a CoreValve in a JenaValve prosthesis: a case report.

PubMed

Lotfi, Shahram; Becker, Michael; Moza, Ajay; Autschbach, Rüdiger; Marx, Nikolaus; Schröder, Jörg

2017-09-10

Transcatheter aortic valve implantation has become an accepted treatment modality for inoperable or high-risk surgical patients with symptomatic severe aortic stenosis. We report the case of a 70-year-old white man who was treated for severe symptomatic aortic regurgitation using transcatheter aortic valve implantation from the apical approach. Because of recurrent cardiac decompensation 4 weeks after implantation he underwent the implantation of a left ventricular assist device system. A year later echocardiography showed a severe transvalvular central insufficiency. Our heart team decided to choose a valve-in-valve approach while reducing the flow rate of left ventricular assist device to minimum and pacing with a frequency of 140 beats/minute. There was an excellent result and our patient is doing well with no relevant insufficiency of the aortic valve at 12-month follow-up. This is the first report about a successful treatment of a stenotic JenaValve using a CoreValve Evolut R; the use of a CoreValve Evolut R prosthesis may be an optimal option for valve-in-valve procedures.

Best practice guidelines for the management of frailty: a British Geriatrics Society, Age UK and Royal College of General Practitioners report.

PubMed

Turner, Gill; Clegg, Andrew

2014-11-01

Older people are majority users of health and social care services in the UK and internationally. Many older people who access these services have frailty, which is a state of vulnerability to adverse outcomes. The existing health care response to frailty is mainly secondary care-based and reactive to the acute health crises of falls, delirium and immobility. A more proactive, integrated, person-centred and community-based response to frailty is required. The British Geriatrics Society Fit for Frailty guideline is consensus best practice guidance for the management of frailty in community and outpatient settings. The BGS recommends that all encounters between health and social care staff and older people in community and outpatient settings should include an assessment for frailty. A gait speed <0.8m/s; a timed-up-and-go test >10s; and a score of ≥3 on the PRISMA 7 questionnaire can indicate frailty. The common clinical presentations of frailty (falls, delirium, sudden immobility) can also be used to indicate the possible presence of frailty. The BGS recommends an holistic medical review based on the principles of comprehensive geriatric assessment (CGA) for all older people identified with frailty. This will: diagnose medical illnesses to optimise treatment; apply evidence-based medication review checklists (e.g. STOPP/START criteria); include discussion with older people and carers to define the impact of illness; work with the older person to create an individualised care and support plan. The BGS does not recommend population screening for frailty using currently available instruments. © The Author 2014. Published by Oxford University Press on behalf of the British Geriatrics Society. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The challenge of valve-in-valve procedures in degenerated Mitroflow bioprostheses and the advantage of using the JenaValve transcatheter heart valve.

PubMed

Conradi, Lenard; Kloth, Benjamin; Seiffert, Moritz; Schirmer, Johannes; Koschyk, Dietmar; Blankenberg, Stefan; Reichenspurner, Hermann; Diemert, Patrick; Treede, Hendrik

2014-12-01

Recently, the feasibility of valve-in-valve procedures using current first-generation transcatheter heart valves (THV) in cases of structural valve degeneration has been reported as an alternative to conventional open repeat valve replacement. By design, certain biological valve xenografts carry a high risk of coronary ostia occlusion due to lateral displacement of leaflets after valve-in-valve procedures. In the present report we aimed to prove feasibility and safety of transapical valve-in-valve implantation of the JenaValve THV in two cases of degenerated Mitroflow bioprostheses. We herein report two cases of successful transapical valve-in-valve procedures using a JenaValve THV implanted in Sorin Mitroflow bioprostheses for structural valve degeneration. Both patients were alive and in good clinical condition at 30 days from the procedure. However, increased transvalvular gradients were noted in both cases. Transcatheter valve-in-valve implantation of a JenaValve THV is a valid alternative for patients with degenerated Mitroflow bioprostheses of sufficient size and in the presence of short distances to the coronary ostia who are too ill for conventional repeat open heart surgery. Increased pressure gradients have to be expected and weighed against the disadvantages of other treatment options when planning such a procedure.

Safety valve

DOEpatents

Bergman, Ulf C.

1984-01-01

The safety valve contains a resilient gland to be held between a valve seat and a valve member and is secured to the valve member by a sleeve surrounding the end of the valve member adjacent to the valve seat. The sleeve is movable relative to the valve member through a limited axial distance and a gap exists between said valve member and said sleeve.

Acquired discrete subaortic stenosis late after mitral valve replacement.

PubMed

Mohan, Jagdish C; Shukla, Madhu; Mohan, Vishwas; Sethi, Arvind

2016-09-01

Although acquired left ventricular outflow obstruction has been reported in a variety of conditions, there are scant reports of its occurrence following mitral valve replacement (MVR). This study describes two female patients, who developed severe discrete subaortic stenosis, five years following MVR. In both cases, the mitral valve was replaced by a porcine Carpentier-Edwards 27-mm bioprosthesis with preservation of mitral valve leaflets. The risk of very late left ventricular outflow tract obstruction after bio-prosthetic MVR with preservation of subvalvular apparatus needs to be kept in mind in symptomatic patients. Copyright © 2016 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

First Employment of British Pharmacology Graduates

ERIC Educational Resources Information Center

Hollingsworth, Michael; Markham, Anthony

2006-01-01

A survey was conducted in UK Universities to identify the employment of pharmacology graduates (BSc, MSc and PhD) 6 months after graduation in 2003. The aim was to provide data for the British Pharmacological Society (BPS) so they could offer advice to interested bodies and to University staff for careers information. 85% of 52 Universities…

Updated clinical indications for transcatheter aortic valve implantation in patients with severe aortic stenosis: expert opinion of the Italian Society of Cardiology and GISE.

PubMed

Indolfi, Ciro; Bartorelli, Antonio L; Berti, Sergio; Golino, Paolo; Esposito, Giovanni; Musumeci, Giuseppe; Petronio, Sonia; Tamburino, Corrado; Tarantini, Giuseppe; Ussia, Gianpaolo; Vassanelli, Corrado; Spaccarotella, Carmen; Violini, Roberto; Mercuro, Giuseppe; Romeo, Francesco

2018-05-01

: The introduction of percutaneous treatment of severe aortic stenosis with transcatheter aortic valve implantation (TAVI) remains one of the greatest achievements of interventional cardiology. In fact, TAVI emerged as a better option than either medical therapy or balloon aortic valvuloplasty for patients who cannot undergo surgical aortic valve replacement (SAVR) or are at high surgical risk. Recently, increased operator experience and improved device systems have led to a worldwide trend toward the extension of TAVI to low-risk or intermediate-risk patients. In this expert opinion paper, we first discuss the basic pathophysiology of aortic stenosis in different settings then the key results of recent clinical investigations on TAVI in intermediate-risk aortic stenosis patients are summarized. Particular emphasis is placed on the results of the nordic aortic valve intervention, placement of aortic transcatheter valves (PARTNER) 2 and Surgical Replacement and Transcatheter Aortic Valve Implantation Randomized trials. The PARTNER 2 was the first large randomized trial that evaluated the outcome of TAVI in patients at intermediate risk. The PARTNER 2 data demonstrated that TAVI is a feasible and reasonable alternative to surgery in intermediate-risk patients (Society of Thoracic Surgeons 4-8%), especially if they are elderly or frail. There was a significant interaction between TAVI approach and mortality, with transfemoral TAVI showing superiority over SAVR. Moreover, we examine the complementary results of the recently concluded Surgical Replacement and Transcatheter Aortic Valve Implantation trial. This prospective randomized trial demonstrated that TAVI is comparable with surgery (primary end point 12.6% in the TAVI group vs. 14.0% in the SAVR group) in severe aortic stenosis patients deemed to be at intermediate risk. We review the most relevant clinical evidence deriving from nonrandomized studies and meta-analyses. Altogether, clinical outcome available data

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

PubMed

Johansen, Peter; Engholt, Henrik; Tang, Mariann; Nybo, Rasmus F; Rasmussen, Per D; Nielsen-Kudsk, Jens Erik

2017-10-13

Patients with degraded bioprosthetic heart valves (BHV) who are not candidates for valve replacement may benefit from transcatheter valve-in-valve (VIV) therapy. However, in smaller-sized surgical BHV the resultant orifice may become too narrow. To overcome this, the valve frame can be fractured by a high-pressure balloon prior to VIV. However, knowledge on fracture pressures and mechanics are prerequisites. The aim of this study was to identify the fracture pressures needed in BHV, and to describe the fracture mechanics. Commonly used BHV of small sizes were mounted on a high-pressure balloon situated in a biplane fluoroscopic system with a high-speed camera. The instant of fracture was captured along with the balloon pressure. The valves were inspected for material protrusion and later dissected for fracture zone investigation and description. The valves with a polymer frame fractured at a lower pressure (8-10 atm) than those with a metal stent (19-26 atm). None of the fractured valves had elements protruding. VIV procedures in small-sized BHV may be performed after prior fracture of the valve frame by high-pressure balloon dilatation. This study provides tentative guidelines for expected balloon sizes and pressures for valve fracturing.

The Economics of Transcatheter Valve Interventions.

PubMed

Sud, Maneesh; Tam, Derrick Y; Wijeysundera, Harindra C

2017-09-01

A subset of patients who require correction of a stenotic or incompetent valve are deemed to be at excessive surgical risk, which precludes surgical repair or replacement. Transcatheter valve interventions are viable alternatives in these patients. However, these technologies are costly, and in the setting of a constrained Canadian health care budget, economic value is an important consideration to allow for fair allocation of scarce resources. Accordingly, we review the economic literature on transcatheter valve interventions, targeting a general audience. Our specific goals are highlighting how best to interpret these studies and discuss the implications of these technologies on the Canadian health care system. Transcatheter aortic valve replacement (TAVR) is a cost-effective alternative for inoperable patients who otherwise would receive medical therapy. When compared with surgical aortic valve replacement (SAVR), TAVR is associated with significant reductions in postprocedure hospital resource use, which offsets the substantially higher cost of the TAVR valve system relative to SAVR valves. Although cost-effectiveness estimates for TAVR in high-risk operable candidates vary widely across studies, based on contemporary data from the perspective of the Canadian health care system, TAVR is likely to provide economic value. Recent studies suggest that when compared with medical therapy for severe degenerative mitral regurgitation, the MitraClip (Abbott, Abbott Park, IL) may offer economic value in high-risk patients; however, in the absence of randomized controlled trials, this is speculative. Nonetheless, these transcatheter technologies represent a paradigm shift in the management of valvular disease; their dissemination will have substantial impact in cardiovascular care delivery. Copyright © 2017 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

Prevalence and Outcomes of Mitral Stenosis in Patients Undergoing Transcatheter Aortic Valve Replacement: Findings From the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapies Registry.

PubMed

Joseph, Lee; Bashir, Mohammad; Xiang, Qun; Yerokun, Babatunde A; Matsouaka, Roland Albert; Vemulapalli, Sreekanth; Kapadia, Samir; Cigarroa, Joaquin E; Zahr, Firas

2018-04-09

This study sought to examine the prevalence of mitral stenosis (MS) and its impact on in-hospital and 1-year clinical outcomes among patients undergoing transcatheter aortic valve replacement (TAVR). Patients with coexisting severe aortic stenosis and MS are increasingly being considered for TAVR. The study cohort included 44,755 patients (age ≥18 years) who underwent TAVR during November 1, 2011, to September 30, 2015, and were registered in Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapies (TVT) Registry. One-year outcomes were assessed by linking TVT registry data of this cohort to patient-specific Centers for Medicare & Medicaid Services administrative claims data (n = 31,453). The primary outcome was the composite of death, stroke, heart failure-related hospitalization, and mitral valve intervention at 1 year. MS was present in 11.6% of cohort (mean age, 82 years; 52% males), being severe in 2.7%. Severe MS was associated with higher in-hospital mortality rates (5.6% vs. 3.9% for nonsevere MS and 4.1% for no MS; p = 0.02). In contrast to those without MS, severe MS group had significantly higher risk for the primary outcome, mortality (1 year), and heart failure-related hospitalization (1 year) (adjusted hazard ratio: 1.2 [95% confidence interval (CI): 1.1 to 1.4], 1.2 [95% CI: 1.0 to 1.4], and 1.3 [95% CI: 1.1 to 1.5], respectively; p < 0.05 for all). Approximately one-tenth of patients undergoing TAVR have concomitant MS. Severe MS is an independent predictor of 1-year adverse clinical outcomes following TAVR. The higher risk for long-term adverse events must be considered when evaluating patients with combined aortic stenosis and MS for TAVR. Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Validation of the Pangao PG-800A36 automatic wrist blood pressure monitor according to the European Society of Hypertension and the British Hypertension Society protocols.

PubMed

Zhao, Hairong; Qiao, Weichang; Zhang, Rui; Cui, Peng; Hou, Fanglin; Zhang, Wenli

2018-02-01

The aim of this study was to validate the PG-800A36 automatic wrist blood pressure monitor according to the European Society of Hypertension International Protocol (ESH-IP) revision 2010 and the British Hypertension Society (BHS) protocols. A total of 33 participants were initially included on the basis of the ESH-IP, followed by examination of 85 participants according to the BHS protocol. The procedures and analysis methods of the protocols were followed precisely with left arm/wrist sequential measurements by two trained observers using a mercury sphygmomanometer and one supervisor using the device. The device passed the ESH-IP with an average difference of 1.45±6.46 mmHg for systolic blood pressure and 1.25±5.10 mmHg for diastolic blood pressure. Furthermore, the A/A grade of the BHS protocol was achieved with an average difference of 1.84±6.94 mmHg for systolic blood pressure and 1.15±6.49 mmHg for diastolic blood pressure, and thus, the device also fulfilled the requirements of the Association for the Advancement of Medical Instrumentation. The Pangao PG-800A36 passed the requirements of the ESH-IP revision 2010 and achieved the A/A grade of the BHS protocol, which can be recommended for self-measurement in the general population.

Society of Thoracic Surgeons Risk Score Predicts Hospital Charges and Resource Utilization After Aortic Valve Replacement

PubMed Central

Arnaoutakis, George J.; George, Timothy J.; Alejo, Diane E.; Merlo, Christian A.; Baumgartner, William A.; Cameron, Duke E.; Shah, Ashish S.

2011-01-01

Context The impact of Society of Thoracic Surgeons (STS) predicted mortality risk score on resource utilization after aortic valve replacement (AVR) has not been previously studied. Objective We hypothesize that increasing STS risk scores in patients having AVR are associated with greater hospital charges. Design, Setting, and Patients Clinical and financial data for patients undergoing AVR at a tertiary care, university hospital over a ten-year period (1/2000–12/2009) were retrospectively reviewed. The current STS formula (v2.61) for in-hospital mortality was used for all patients. After stratification into risk quartiles (Q), index admission hospital charges were compared across risk strata with Rank-Sum tests. Linear regression and Spearman’s coefficient assessed correlation and goodness of fit. Multivariable analysis assessed relative contributions of individual variables on overall charges. Main Outcome Measures Inflation-adjusted index hospitalization total charges Results 553 patients had AVR during the study period. Average predicted mortality was 2.9% (±3.4) and actual mortality was 3.4% for AVR. Median charges were greater in the upper Q of AVR patients [Q1–3,$39,949 (IQR32,708–51,323) vs Q4,$62,301 (IQR45,952–97,103), p=<0.01]. On univariate linear regression, there was a positive correlation between STS risk score and log-transformed charges (coefficient: 0.06, 95%CI 0.05–0.07, p<0.01). Spearman’s correlation R-value was 0.51. This positive correlation persisted in risk-adjusted multivariable linear regression. Each 1% increase in STS risk score was associated with an added $3,000 in hospital charges. Conclusions This study showed increasing STS risk score predicts greater charges after AVR. As competing therapies such as percutaneous valve replacement emerge to treat high risk patients, these results serve as a benchmark to compare resource utilization. PMID:21497834

The British Society for Clinical Cytology Certificate of Competence in Cytology Screening: a report of the first 3 years' experience.

PubMed

McGoogan, E; Chapman, P A

1992-01-01

In 1988 the Department of Health (DOH) recognized the cytology screener grade of laboratory staff. Cytology screeners have a 2 year training period after which they must sit a 'competence examination'. The British Society for Clinical Cytology offers an examination to meet the DOH specification. It consists of a written paper, a practical screening test, a spot test and a short viva voce. The screening test is paramount and candidates who miss a dyskaryotic smear cannot be successful. In the first 3 years there have been 22 examinations, 294 candidates and a pass rate of 76%. The majority of candidates were Cytology Screeners of 2-3 years experience but significant numbers of Medical Laboratory Scientific Officers (MLSOs) and senior MLSOs also chose to sit the examination.

Latest-Generation Transcatheter Aortic Valve Replacement Devices and Procedures.

PubMed

Chamandi, Chekrallah; Puri, Rishi; Rodriguez-Gabella, Tania; Rodés-Cabau, Josep

2017-09-01

Transcatheter aortic valve replacement (TAVR) is a well-established treatment for patients with severe symptomatic aortic stenosis who are at high or prohibitive surgical risk. More recently, TAVR has emerged as a valid alternative to surgical aortic valve replacement for treating intermediate-risk patients, and several studies are currently evaluating the role of TAVR in low-risk patients. Transcatheter heart valve (THV) technologies have evolved considerably over time, and important iterations have been implemented in many of the latest-generation devices to (1) reduce the size and improve delivery system properties; (2) improve valve deployment, repositioning, and retrievability; and (3) reduce paravalvular leaks. This article reviews the main characteristics of, and clinical results associated with, the newer-generation THVs while providing an overview of novel TAVR indications. Copyright © 2017 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

Should high risk patients with concomitant severe aortic stenosis and mitral valve disease undergo double valve surgery in the TAVR era?

PubMed

Yu, Pey-Jen; Mattia, Allan; Cassiere, Hugh A; Esposito, Rick; Manetta, Frank; Kohn, Nina; Hartman, Alan R

2017-12-29

Significant mitral regurgitation in patients undergoing transcatheter aortic valve replacement (TAVR) is associated with increased mortality. The aim of this study is to determine if surgical correction of both aortic and mitral valves in high risk patients with concomitant valvular disease would offer patients better outcomes than TAVR alone. A retrospective analysis of 43 high-risk patients who underwent concomitant surgical aortic valve replacement and mitral valve surgery from 2008 to 2012 was performed. Immediate and long term survival were assessed. There were 43 high-risk patients with severe aortic stenosis undergoing concomitant surgical aortic valve replacement and mitral valve surgery. The average age was 80 ± 6 years old. Nineteen (44%) patients had prior cardiac surgery, 15 (34.9%) patients had chronic obstructive lung disease, and 39 (91%) patients were in congestive heart failure. The mean Society of Thoracic Surgeons Predicted Risk of Mortality for isolated surgical aortic valve replacement for the cohort was 10.1% ± 6.4%. Five patients (11.6%) died during the index admission and/or within thirty days of surgery. Mortality rate was 25% at six months, 35% at 1 year and 45% at 2 years. There was no correlation between individual preoperative risk factors and mortality. High-risk patients with severe aortic stenosis and mitral valve disease undergoing concomitant surgical aortic valve replacement and mitral valve surgery may have similar long term survival as that described for such patients undergoing TAVR. Surgical correction of double valvular disease in this patient population may not confer mortality benefit compared to TAVR alone.

Validation of the Pangao PG-800B11 blood pressure monitor according to the European Society of Hypertension and the British Hypertension Society protocols.

PubMed

Bing, Sen; Zhang, Cunhai; Wang, Liping; Li, Linyi; Wan, Yi

2014-12-01

The study aimed to determine the accuracy of the fully automated oscillometric upper-arm blood pressure (BP) monitor Pangao PG-800B11 according to the European Society of Hypertension-International Protocol (ESH-IP) revision 2010 and the British Hypertension Society (BHS) protocol 1993. Data from 33 participants were initially examined according to the ESH-IP revision 2010. Furthermore, 52 participants were then enrolled to fulfill the BHS protocol requirements. In all participants, sequential left arm measurements were performed by two trained observers using a mercury sphygmomanometer and one supervisor using the device. The protocols' requirements were followed precisely. The device passed all parts of the ESH protocol for systolic blood pressure (SBP) and diastolic blood pressure (DBP) and was graded A according to the criteria of the BHS protocol for both SBP and DBP. The A/A grade was achieved in low (<130/80 mmHg), medium (130-160/80-100 mmHg), and high (>160/100 mmHg) BP categories. The mean BP difference between PG-800B11 and observers in the 85 participants was -0.6±5.0 mmHg for SBP and -0.6±4.5 mmHg for DBP; thus, the device also fulfilled the requirements of the Association for the Advancement of Medical Instrumentation (AAMI). The Pangao PG-800B11 passed all requirements of the ESH-IP revision 2010 and achieved A/A grade of the BHS protocol across a wide range of BPs.

Check valve

DOEpatents

Upton, Hubert Allen; Garcia, Pablo

1999-08-24

A check valve for use in a GDCS of a nuclear reactor and having a motor driven disk including a rotatable armature for rotating the check valve disk over its entire range of motion is described. In one embodiment, the check valve includes a valve body having a coolant flow channel extending therethrough. The coolant flow channel includes an inlet end and an outlet end. A valve body seat is located on an inner surface of the valve body. The check valve further includes a disk assembly, sometimes referred to as the motor driven disc, having a counterweight and a disk shaped valve. The disk valve includes a disk base having a seat for seating with the valve body seat. The disk assembly further includes a first hinge pin member which extends at least partially through the disk assembly and is engaged to the disk. The disk valve is rotatable relative to the first hinge pin member. The check valve also includes a motor having a stator frame with a stator bore therein. An armature is rotatably positioned within the stator bore and the armature is coupled to the disk valve to cause the disk valve to rotate about its full range of motion.

Check valve

DOEpatents

Upton, H.A.; Garcia, P.

1999-08-24

A check valve for use in a GDCS of a nuclear reactor and having a motor driven disk including a rotatable armature for rotating the check valve disk over its entire range of motion is described. In one embodiment, the check valve includes a valve body having a coolant flow channel extending therethrough. The coolant flow channel includes an inlet end and an outlet end. A valve body seat is located on an inner surface of the valve body. The check valve further includes a disk assembly, sometimes referred to as the motor driven disc, having a counterweight and a disk shaped valve. The disk valve includes a disk base having a seat for seating with the valve body seat. The disk assembly further includes a first hinge pin member which extends at least partially through the disk assembly and is engaged to the disk. The disk valve is rotatable relative to the first hinge pin member. The check valve also includes a motor having a stator frame with a stator bore therein. An armature is rotatably positioned within the stator bore and the armature is coupled to the disk valve to cause the disk valve to rotate about its full range of motion. 5 figs.

Neurotrophin 3 upregulates proliferation and collagen production in human aortic valve interstitial cells: a potential role in aortic valve sclerosis.

PubMed

Yao, Qingzhou; Song, Rui; Ao, Lihua; Cleveland, Joseph C; Fullerton, David A; Meng, Xianzhong

2017-06-01

Calcific aortic valve disease (CAVD) is a leading cardiovascular disorder in the elderly. Diseased aortic valves are characterized by sclerosis (fibrosis) and nodular calcification. Sclerosis, an early pathological change, is caused by aortic valve interstitial cell (AVIC) proliferation and overproduction of extracellular matrix (ECM) proteins. However, the mechanism of aortic valve sclerosis remains unclear. Recently, we observed that diseased human aortic valves overexpress growth factor neurotrophin 3 (NT3). In the present study, we tested the hypothesis that NT3 is a profibrogenic factor to human AVICs. AVICs isolated from normal human aortic valves were cultured in M199 growth medium and treated with recombinant human NT3 (0.10 µg/ml). An exposure to NT3 induced AVIC proliferation, upregulated the production of collagen and matrix metalloproteinase (MMP), and augmented collagen deposition. These changes were abolished by inhibition of the Trk receptors. NT3 induced Akt phosphorylation and increased cyclin D1 protein levels in a Trk receptor-dependent fashion. Inhibition of Akt abrogated the effect of NT3 on cyclin D1 production. Furthermore, inhibition of either Akt or cyclin D1 suppressed NT3-induced cellular proliferation and MMP-9 and collagen production, as well as collagen deposition. Thus, NT3 upregulates cellular proliferation, ECM protein production, and collagen deposition in human AVICs. It exerts these effects through the Trk-Akt-cyclin D1 cascade. NT3 is a profibrogenic mediator in human aortic valve, and overproduction of NT3 by aortic valve tissue may contribute to the mechanism of valvular sclerosis. Copyright © 2017 the American Physiological Society.

Valve Repair Is Superior to Replacement in Most Patients With Coexisting Degenerative Mitral Valve and Coronary Artery Diseases.

PubMed

Javadikasgari, Hoda; Gillinov, A Marc; Idrees, Jay J; Mihaljevic, Tomislav; Suri, Rakesh M; Raza, Sajjad; Houghtaling, Penny L; Svensson, Lars G; Navia, José L; Mick, Stephanie L; Desai, Milind Y; Sabik, Joseph F; Blackstone, Eugene H

2017-06-01

For mitral regurgitation (MR) from degenerative mitral disease in patients with coexisting coronary artery disease, the appropriate surgical strategy remains controversial. From 1985 to 2011, 1,071 adults (age 70 ± 9.3 years, 77% men) underwent combined coronary artery bypass grafting and either mitral valve repair (n = 872, 81%) or replacement (n=199, 19%) for degenerative MR. Propensity matching (177 patient pairs, 89% of possible matches) was used to compare early outcomes and time-related recurrence of MR after mitral valve repair, mitral valve reoperation, and mortality. Risk factors for death were identified with multivariable, multiphase hazard-function analysis. Patients undergoing valve replacement were older, with more valve calcification and a higher prevalence of preoperative atrial fibrillation and heart failure (all p < .0001). Among matched pairs, mitral replacement versus repair was associated with higher hospital mortality (5.0% vs 1.0%, p = .0001) and more postoperative renal failure (7.0% vs 3.2%, p = .01), reexplorations for bleeding (6.0% vs 3.1%, p = .05), and respiratory failure (14% vs 4.7%, p < .0001). Of matched patients undergoing repair, 18% had MR above 3+ by 5 years. Mitral valve durability was similar between matched groups, but survival at 15 years was 18% after replacement versus 52% after repair. Nomograms from the multivariable equation revealed that in 94% of cases, 10-year survival was calculated to be higher after repair than after replacement. In patients with coexisting degenerative mitral valve and coronary artery diseases, mitral valve repair is expected to confer a long-term survival advantage over replacement despite some recurrence of MR. When feasible, it is the procedure of choice for these patients. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Influence of aortic valve leaflet calcification on dynamic aortic valve motion assessed by cardiac computed tomography.

PubMed

Minami, Keisuke; Yoneyama, Kihei; Izumo, Masaki; Suzuki, Kengo; Ogawa, Yasuyoshi; Chikaraishi, Kousuke; Ogawa, Yukihisa; Kobayashi, Yasuyuki; Furukawa, Toshiyuki; Tanabe, Yasuhiro; Akashi, Yoshihiro J

Computed tomography is the best noninvasive imaging modality for evaluating valve leaflet calcification. To evaluate the association of aortic valve leaflet calcification with instantaneous valve opening and closing using dynamic multidetector computed tomography (MDCT). We retrospectively evaluated 58 consecutive patients who underwent dynamic MDCT imaging. Aortic valve calcification (AVC) was quantified using the Agatston method. The aortic valve area (AVA) tracking curves were derived by planimetry during the cardiac cycle using all 20 phases (5% reconstruction). da/dt in cm 2 /s was calculated as the rate of change of AVA during opening (positive) or closing (negative). Patients were divided into 3 three groups according to Agatston score quartile: no AVC (Q2, Score 0, n = 18), mild AVC (Q3, Score 1-2254, n = 24), and severe AVC (Q4 Score >2254, n = 14). In multivariable linear regression, compared to the non AVC group, the mild and severe AVC groups had lower maximum AVA (by -1.71 cm 2 and -2.25 cm 2 , respectively), lower peak positive da/dt (by -21.88 cm 2 /s and -26.65 cm 2 /s, respectively), and higher peak negative da/dt (by 13.78 cm 2 /s and 18.11 cm 2 /s, respectively) (p < 0.05 for all comparisons). AVA and its opening and closing were influenced by leaflet calcification. The present study demonstrates the ability of dynamic MDCT imaging to assess quantitative aortic valve motion in a clinical setting. Copyright © 2016 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

Transcatheter Aortic Valve Replacement for Native Aortic Valve Regurgitation

PubMed Central

Spina, Roberto; Anthony, Chris; Muller, David WM

2015-01-01

Transcatheter aortic valve replacement with either the balloon-expandable Edwards SAPIEN XT valve, or the self-expandable CoreValve prosthesis has become the established therapeutic modality for severe aortic valve stenosis in patients who are not deemed suitable for surgical intervention due to excessively high operative risk. Native aortic valve regurgitation, defined as primary aortic incompetence not associated with aortic stenosis or failed valve replacement, on the other hand, is still considered a relative contraindication for transcatheter aortic valve therapies, because of the absence of annular or leaflet calcification required for secure anchoring of the transcatheter heart valve. In addition, severe aortic regurgitation often coexists with aortic root or ascending aorta dilatation, the treatment of which mandates operative intervention. For these reasons, transcatheter aortic valve replacement has been only sporadically used to treat pure aortic incompetence, typically on a compassionate basis and in surgically inoperable patients. More recently, however, transcatheter aortic valve replacement for native aortic valve regurgitation has been trialled with newer-generation heart valves, with encouraging results, and new ancillary devices have emerged that are designed to stabilize the annulus–root complex. In this paper we review the clinical context, technical characteristics and outcomes associated with transcatheter treatment of native aortic valve regurgitation. PMID:29588674

Fast-Acting Valve

NASA Technical Reports Server (NTRS)

Wojciechowski, Bogdan V. (Inventor); Pegg, Robert J. (Inventor)

2003-01-01

A fast-acting valve includes an annular valve seat that defines an annular valve orifice between the edges of the annular valve seat, an annular valve plug sized to cover the valve orifice when the valve is closed, and a valve-plug holder for moving the annular valve plug on and off the annular valve seat. The use of an annular orifice reduces the characteristic distance between the edges of the valve seat. Rather than this distance being equal to the diameter of the orifice, as it is for a conventional circular orifice, the characteristic distance equals the distance between the inner and outer radii (for a circular annulus). The reduced characteristic distance greatly reduces the gap required between the annular valve plug and the annular valve seat for the valve to be fully open, thereby greatly reducing the required stroke and corresponding speed and acceleration of the annular valve plug. The use of a valve-plug holder that is under independent control to move the annular valve plug between its open and closed positions is important for achieving controllable fast operation of the valve.

Trends in Aortic Valve Replacement Procedures Between 2009 and 2015: Has Transcatheter Aortic Valve Replacement Made a Difference?

PubMed

Culler, Steven D; Cohen, David J; Brown, Phillip P; Kugelmass, Aaron D; Reynolds, Matthew R; Ambrose, Karen; Schlosser, Michael L; Simon, April W; Katz, Marc R

2018-04-01

This study reports trends in volume and adverse events associated with isolated aortic valve procedures performed in Medicare beneficiaries between 2009 and 2015. This retrospective study used the annual fiscal year Medicare Provider Analysis and Review file to identify all Medicare beneficiaries undergoing an isolated aortic valve procedure. Outcome measures included three mortality rates and nine in-hospital adverse events. The final study population consisted of 233,660 hospitalizations. During the study period, Medicare beneficiaries undergoing an aortic valve procedure increased from 22,076 to 49,362, for an average annual growth rate of 14.45%. Transcatheter aortic valve replacement (TAVR) procedures per 100,000 Medicare beneficiaries grew from 10.7 in 2012 to 41.1 in 2015. Overall, in-hospital mortality rates, cumulative 30-day mortality rates, and 90-day postdischarge mortality rates declined annually during the study period. However, the 90-day mortality rate for TAVR was nearly double the rate for the tissue surgical aortic valve replacement group. Nearly 68% of Medicare beneficiaries experienced at least one in-hospital adverse event during their index hospitalization. Medicare beneficiaries undergoing TAVR had the lowest observed adverse events rates among the aortic valve procedures in 2015. The total number of Medicare beneficiaries undergoing isolated aortic valve procedures increased from 47.5 to 88.9 per 100,000 Medicare beneficiaries during the study period. Aortic valve procedures increased significantly during this study period primarily due to the increase in TAVR, with clinical outcomes improving as well. Although long-term outcomes of TAVR are still under investigation, these results are promising. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Management of spontaneous pneumothorax compared to British Thoracic Society (BTS) 2003 guidelines: a district general hospital audit.

PubMed

Medford, Andrew Rl; Pepperell, Justin Ct

2007-10-01

In 1993, the British Thoracic Society (BTS) issued guidelines for the management of spontaneous pneumothorax (SP). These were refined in 2003. To determine adherence to the 2003 BTS SP guidelines in a district general hospital. An initial retrospective audit of 52 episodes of acute SP was performed. Subsequent intervention involved a junior doctor educational update on both the 2003 BTS guidelines and the initial audit results, and the setting up of an online guideline hyperlink. After the educational intervention a further prospective re-audit of 28 SP episodes was performed. Management of SP deviated considerably from the 2003 BTS guidelines in the initial audit - deviation rate 26.9%. After the intervention, a number of clinical management deviations persisted (32.1% deviation rate); these included failure to insert a chest drain despite unsuccessful aspiration, and attempting aspiration of symptomatic secondary SPs. Specific tools to improve standards might include a pneumothorax proforma to improve record keeping and a pneumothorax care pathway to reduce management deviations compared to BTS guidelines. Successful change also requires identification of the total target audience for any educational intervention.

Dispensers, obeah and quackery: medical rivalries in post-slavery British Guiana.

PubMed

De Barros, Juanita

2007-08-01

This paper examines the ambiguous place of medical assistants-dispensers-in a post-slavery British Caribbean colony, British Guiana, from the end of slavery in the 1830s to the early twentieth century. Although the latter were crucial to the functioning of the colonial medical system, local physicians resented them, complaining about the economic threat they posed and at times condemning them as quacks. These attacks were part of a wider discussion about the composition of the medical profession and the role of medical auxiliaries in colonial society, and to an extent, they echoed debates conducted in other jurisdictions in this period. But in the British Caribbean, this discussion was significantly different. There, long-standing views about obeah-an Afro-Creole medico-religious practice-as a particularly dangerous and uncivilised type of quackery was part of the discursive context. That those participating in this debate included African-descended physicians whose arrival in the medical profession was recent and contested demonstrates the vexed and complex nature of professionalisation in a post-slavery society.

Trans-catheter aortic valve implantation after previous aortic homograft surgery.

PubMed

Drews, Thorsten; Pasic, Miralem; Buz, Semih; Unbehaun, Axel

2011-12-01

In patients with previous heart surgery, the operative risk is elevated during conventional aortic valve re-operations. Trans-catheter aortic valve implantation is a new method for the treatment of high-risk patients. Nevertheless, this new procedure carries potential risks in patients with previous homograft implantation in aortic position. Between April 2008 and February 2011, 345 consecutive patients (mean EuroSCORE (European System for Cardiac Operative Risk Evaluation): 38 ± 20%; mean Society of Thoracic Surgeons (STS) Mortality Score: 19 ± 16%; mean age: 80 ± 8 years; 111 men and 234 women) underwent trans-apical aortic valve implantation. In three patients, previous aortic homograft implantation had been performed. Homograft degeneration causing combined valve stenosis and incompetence made re-operation necessary. In all three patients, the aortic valve could be implanted using the trans-apical approach, and the procedure was successful. In two patients, there was slight paravalvular leakage of the aortic prosthesis and the other patient had slight central leakage. Neither ostium obstruction nor mitral valve damage was observed. Trans-catheter valve implantation can be performed successfully after previous homograft implantation. Particular care should be taken to achieve optimal valve positioning, not to obstruct the ostium of the coronary vessels due to the changed anatomic situation and not to cause annulus rupture. Copyright © 2011 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

Bioprosthetic Valve Fracture During Valve-in-valve TAVR: Bench to Bedside

PubMed Central

Saxon, John T; Allen, Keith B; Cohen, David J

2018-01-01

Valve-in-valve (VIV) transcatheter aortic valve replacement (TAVR) has been established as a safe and effective means of treating failed surgical bioprosthetic valves (BPVs) in patients at high risk for complications related to reoperation. Patients who undergo VIV TAVR are at risk of patient–prosthesis mismatch, as the transcatheter heart valve (THV) is implanted within the ring of the existing BPV, limiting full expansion and reducing the maximum achievable effective orifice area of the THV. Importantly, patient–prosthesis mismatch and high residual transvalvular gradients are associated with reduced survival following VIV TAVR. Bioprosthetic valve fracture (BVF) is as a novel technique to address this problem. During BPV, a non-compliant valvuloplasty balloon is positioned within the BPV frame, and a highpressure balloon inflation is performed to fracture the surgical sewing ring of the BPV. This allows for further expansion of the BPV as well as the implanted THV, thus increasing the maximum effective orifice area that can be achieved after VIV TAVR. This review focuses on the current evidence base for BVF to facilitate VIV TAVR, including initial bench testing, procedural technique, clinical experience and future directions. PMID:29593832

Bioprosthetic Valve Fracture During Valve-in-valve TAVR: Bench to Bedside.

PubMed

Saxon, John T; Allen, Keith B; Cohen, David J; Chhatriwalla, Adnan K

2018-01-01

Valve-in-valve (VIV) transcatheter aortic valve replacement (TAVR) has been established as a safe and effective means of treating failed surgical bioprosthetic valves (BPVs) in patients at high risk for complications related to reoperation. Patients who undergo VIV TAVR are at risk of patient-prosthesis mismatch, as the transcatheter heart valve (THV) is implanted within the ring of the existing BPV, limiting full expansion and reducing the maximum achievable effective orifice area of the THV. Importantly, patient-prosthesis mismatch and high residual transvalvular gradients are associated with reduced survival following VIV TAVR. Bioprosthetic valve fracture (BVF) is as a novel technique to address this problem. During BPV, a non-compliant valvuloplasty balloon is positioned within the BPV frame, and a highpressure balloon inflation is performed to fracture the surgical sewing ring of the BPV. This allows for further expansion of the BPV as well as the implanted THV, thus increasing the maximum effective orifice area that can be achieved after VIV TAVR. This review focuses on the current evidence base for BVF to facilitate VIV TAVR, including initial bench testing, procedural technique, clinical experience and future directions.

Control Valve

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, Wayne R.

A control valve includes a first conduit having a first inlet and a first outlet and defining a first passage; a second conduit having a second inlet and a second outlet and defining a second passage, the second conduit extending into the first passage such that the second inlet is located within the first passage; and a valve plate disposed pivotably within the first passage, the valve plate defining a valve plate surface. Pivoting of the valve plate within the first passage varies flow from the first inlet to the first outlet and the valve plate is pivotal between amore » first position and a second position such that in the first position the valve plate substantially prevents fluid communication between the first passage and the second passage and such that in the second position the valve plate permits fluid communication between the first passage and the second passage.« less

Acute Kidney Injury Classification Underestimates Long-Term Mortality After Cardiac Valve Operations.

PubMed

Bouma, Hjalmar R; Mungroop, Hubert E; de Geus, A Fred; Huisman, Daniel D; Nijsten, Maarten W N; Mariani, Massimo A; Scheeren, Thomas W L; Burgerhof, Johannes G M; Henning, Robert H; Epema, Anne H

2018-03-01

Perioperative acute kidney injury (AKI) is an important predictor of long-term all-cause mortality after coronary artery bypass (CABG). However, the effect of AKI on long-term mortality after cardiac valve operations is hitherto undocumented. Perioperative renal injury and long-term all-cause mortality after valve operations were studied in a prospective cohort of patients undergoing solitary valve operations (n=2,806) or valve operations combined with CABG (n=1,260) with up to 18 years of follow-up. Postoperative serum creatinine increase was classified according to AKI 0-3. Patients undergoing solitary CABG (n=4,938) with cardiopulmonary bypass served as reference. In both valve and valve+CABG operations, postoperative renal injury of AKI stage 1 or higher was progressively associated with an increase in long-term mortality (HR 2.27, p<0.05 for valve; HR 1.65, p<0.05 for valve operations combined with CABG; HR 1.56, p<0.05 for CABG). Notably, the mortality risk increased already substantially at serum creatinine rises of 10-25%, i.e. far below the threshold for AKI stage 1 after valve operations (HR 1.39, p<0.05), but not after valve operations combined with CABG or CABG only. An increase in serum creatinine by more than 10%during the first week following valve operation is associated with an increased risk for long-term mortality following cardiac valve operation. Thus, AKI-classification clearly underestimates long-term mortality risk in patients undergoing valve operations. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Nuclear radiation actuated valve

DOEpatents

Christiansen, David W.; Schively, Dixon P.

1985-01-01

A nuclear radiation actuated valve for a nuclear reactor. The valve has a valve first part (such as a valve rod with piston) and a valve second part (such as a valve tube surrounding the valve rod, with the valve tube having side slots surrounding the piston). Both valve parts have known nuclear radiation swelling characteristics. The valve's first part is positioned to receive nuclear radiation from the nuclear reactor's fuel region. The valve's second part is positioned so that its nuclear radiation induced swelling is different from that of the valve's first part. The valve's second part also is positioned so that the valve's first and second parts create a valve orifice which changes in size due to the different nuclear radiation caused swelling of the valve's first part compared to the valve's second part. The valve may be used in a nuclear reactor's core coolant system.

Transcatheter aortic valve implantation for failing surgical aortic bioprosthetic valve: from concept to clinical application and evaluation (part 2).

PubMed

Piazza, Nicolo; Bleiziffer, Sabine; Brockmann, Gernot; Hendrick, Ruge; Deutsch, Marcus-André; Opitz, Anke; Mazzitelli, Domenico; Tassani-Prell, Peter; Schreiber, Christian; Lange, Rüdiger

2011-07-01

This study sought to review the acute procedural outcomes of patients who underwent transcatheter aortic valve (TAV)-in-surgical aortic valve (SAV) implantation at the German Heart Center, Munich, and to summarize the existing literature on TAV-in-SAV implantation (n = 47). There are several case reports and small case series describing transcatheter aortic valve implantation for a failing surgical aortic valve bioprosthesis (TAV-in-SAV implantation). From January 2007 to March 2011, 20 out of 556 patients underwent a TAV-in-SAV implantation at the German Heart Center Munich. Baseline characteristics and clinical outcome data were prospectively entered into a dedicated database. The mean patient age was 75 ± 13 years, and the mean logistic European System for Cardiac Operative Risk Evaluation and Society of Thoracic Surgeons' Risk Model scores were 27 ± 13% and 7 ± 4%, respectively. Of the 20 patients, 14 had stented and 6 had stentless surgical bioprostheses. Most cases (12 of 20) were performed via the transapical route using a 23-mm Edwards Sapien prosthesis (Edwards Lifesciences, Irvine, California). Successful implantation of a TAV in a SAV with the patient leaving the catheterization laboratory alive was achieved in 18 of 20 patients. The mean transaortic valve gradient was 20.0 ± 7.5 mm Hg. None-to-trivial, mild, and mild-to-moderate paravalvular aortic regurgitation was observed in 10, 6, and 2 patients, respectively. We experienced 1 intraprocedural death following pre-implant balloon aortic valvuloplasty ("stone heart") and 2 further in-hospital deaths due to myocardial infarction. TAV-in-SAV implantation is a safe and feasible treatment for high-risk patients with failing aortic bioprosthetic valves and should be considered as part of the armamentarium in the treatment of aortic bioprosthetic valve failure. Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Valve thrombosis following transcatheter aortic valve implantation: a systematic review.

PubMed

Córdoba-Soriano, Juan G; Puri, Rishi; Amat-Santos, Ignacio; Ribeiro, Henrique B; Abdul-Jawad Altisent, Omar; del Trigo, María; Paradis, Jean-Michel; Dumont, Eric; Urena, Marina; Rodés-Cabau, Josep

2015-03-01

Despite the rapid global uptake of transcatheter aortic valve implantation, valve trombosis has yet to be systematically evaluated in this field. The aim of this study was to determine the clinical characteristics, diagnostic criteria, and treatment outcomes of patients diagnosed with valve thrombosis following transcatheter aortic valve implantation through a systematic review of published data. Literature published between 2002 and 2012 on valve thrombosis as a complication of transcatheter aortic valve implantation was identified through a systematic electronic search. A total of 11 publications were identified, describing 16 patients (mean age, 80 [5] years, 65% men). All but 1 patient (94%) received a balloon-expandable valve. All patients received dual antiplatelet therapy immediately following the procedure and continued to take either mono- or dual antiplatelet therapy at the time of valve thrombosis diagnosis. Valve thrombosis was diagnosed at a median of 6 months post-procedure, with progressive dyspnea being the most common symptom. A significant increase in transvalvular gradient (from 10 [4] to 40 [12] mmHg) was the most common echocardiographic feature, in addition to leaflet thickening. Thrombus was not directly visualized with echocardiography. Three patients underwent valve explantation, and the remaining received warfarin, which effectively restored the mean transvalvular gradient to baseline within 2 months. Systemic embolism was not a feature of valve thrombosis post-transcatheter aortic valve implantation. Although a rare, yet likely under-reported complication of post-transcatheter aortic valve implantation, progressive dyspnea coupled with an increasing transvalvular gradient on echocardiography within the months following the intervention likely signifies valve thrombosis. While direct thrombus visualization appears difficult, prompt initiation of oral anticoagulation therapy effectively restores baseline valve function. Copyright © 2014

JenaValve.

PubMed

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.

Depressurization valve

DOEpatents

Skoda, G.I.

1989-03-28

A depressurization valve for use in relieving completely the pressure in a simplified boiling water reactor is disclosed. The normally closed and sealed valve is provided with a valve body defining a conduit from an outlet of a manifold from the reactor through a valve seat. A closing valve disk is configured for fitting to the valve seat to normally close the valve. The seat below the disk is provided with a radially extending annulus extending a short distance into the aperture defined by the seat. The disk is correspondingly provided with a longitudinally extending annulus that extends downwardly through the aperture defined by the seat towards the high pressure side of the valve body. A ring shaped membrane is endlessly welded to the seat annulus and to the disk annulus. The membrane is conformed over the confronted surface of the seat and disk in a C-sectioned configuration to seal the depressurization valve against the possibility of weeping. The disk is held to the closed position by an elongate stem extending away from the high pressure side of the valve body. The stem has a flange configured integrally to the stem for bias by two springs. The first spring acts from a portion of the housing overlying the disk on the stem flange adjacent the disk. This spring urges the stem and attached disk away from the seat and thus will cause the valve to open at any pressure. A second spring-preferably of the Belleville variety-acts on a latch plate surrounding and freely moving relative to the end of the stem. This second spring overcomes the bias of the first spring and any pressure acting upon the disk. This Belleville spring maintains through its spring force the valve in the closed position. At the same time, the latch plate with its freedom of movement relative to the stem allows the stem to thermally expand during valve temperature excursion.

Making Kew Observatory: the Royal Society, the British Association and the politics of early Victorian science.

PubMed

Macdonald, Lee T

2015-09-01

Built in 1769 as a private observatory for King George III, Kew Observatory was taken over in 1842 by the British Association for the Advancement of Science (BAAS). It was then quickly transformed into what some claimed to be a 'physical observatory' of the sort proposed by John Herschel - an observatory that gathered data in a wide range of physical sciences, including geomagnetism and meteorology, rather than just astronomy. Yet this article argues that the institution which emerged in the 1840s was different in many ways from that envisaged by Herschel. It uses a chronological framework to show how, at every stage, the geophysicist and Royal Artillery officer Edward Sabine manipulated the project towards his own agenda: an independent observatory through which he could control the geomagnetic and meteorological research, including the ongoing 'Magnetic Crusade'. The political machinations surrounding Kew Observatory, within the Royal Society and the BAAS, may help to illuminate the complex politics of science in early Victorian Britain, particularly the role of 'scientific servicemen' such as Sabine. Both the diversity of activities at Kew and the complexity of the observatory's origins make its study important in the context of the growing field of the 'observatory sciences'.

Fast valve

DOEpatents

Van Dyke, W.J.

1992-04-07

A fast valve is disclosed that can close on the order of 7 milliseconds. It is closed by the force of a compressed air spring with the moving parts of the valve designed to be of very light weight and the valve gate being of wedge shaped with O-ring sealed faces to provide sealing contact without metal to metal contact. The combination of the O-ring seal and an air cushion create a soft final movement of the valve closure to prevent the fast air acting valve from having a harsh closing. 4 figs.

Fast valve

DOEpatents

Van Dyke, William J.

1992-01-01

A fast valve is disclosed that can close on the order of 7 milliseconds. It is closed by the force of a compressed air spring with the moving parts of the valve designed to be of very light weight and the valve gate being of wedge shaped with O-ring sealed faces to provide sealing contact without metal to metal contact. The combination of the O-ring seal and an air cushion create a soft final movement of the valve closure to prevent the fast air acting valve from having a harsh closing.

Proceedings of the symposium on inservice testing of pumps and valves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1990-10-01

The 1990 Symposium on Inservice Testing of Pumps and Valves, jointly sponsored by the Board on Nuclear Codes and Standards of the American Society of Mechanical Engineers and by the Nuclear Regulatory Commission, provided a forum for the discussion of current programs and methods for inservice testing at nuclear power plants. The symposium also provided an opportunity to discuss the need to improve inservice testing in order to ensure the reliable performance of pumps and valves. The participation of industry representatives, regulators, and consultants resulted in the discussion of a broad spectrum of ideas and perspectives regarding the improvement ofmore » inservice testing of pumps and valves at nuclear power plants.« less

A comparison of conventional surgery, transcatheter aortic valve replacement, and sutureless valves in "real-world" patients with aortic stenosis and intermediate- to high-risk profile.

PubMed

Muneretto, Claudio; Alfieri, Ottavio; Cesana, Bruno Mario; Bisleri, Gianluigi; De Bonis, Michele; Di Bartolomeo, Roberto; Savini, Carlo; Folesani, Gianluca; Di Bacco, Lorenzo; Rambaldini, Manfredo; Maureira, Juan Pablo; Laborde, Francois; Tespili, Maurizio; Repossini, Alberto; Folliguet, Thierry

2015-12-01

We sought to investigate the clinical outcomes of patients with isolated severe aortic stenosis and an intermediate- to high-risk profile treated by means of conventional surgery (surgical aortic valve replacement), sutureless valve implantation, or transcatheter aortic valve replacement in a multicenter evaluation. Among 991 consecutive patients with isolated severe aortic stenosis and an intermediate- to high-risk profile (Society of Thoracic Surgeons score >4 and logistic European System for Cardiac Operative Risk Evaluation I >10), a propensity score analysis was performed on the basis of the therapeutic strategy: surgical aortic valve replacement (n = 204), sutureless valve implantation (n = 204), and transcatheter aortic valve replacement (n = 204). Primary end points were 30-day mortality and overall survival at 24-month follow-up; the secondary end point was survival free from a composite end point of major adverse cardiac events (defined as cardiac-related mortality, myocardial infarction, cerebrovascular accidents, and major hemorrhagic events) and periprosthetic regurgitation greater than 2. Thirty-day mortality was significantly higher in the transcatheter aortic valve replacement group (surgical aortic valve replacement = 3.4% vs sutureless = 5.8% vs transcatheter aortic valve replacement = 9.8%; P = .005). The incidence of postprocedural was 3.9% in asurgical aortic valve replacement vs 9.8% in sutureless vs 14.7% in transcatheter aortic valve replacement (P< .001) and peripheral vascular complications occurred in 0% of surgicalaortic valve replacement vs 0% of sutureless vs 9.8% transcatheter aortic valve replacement (P< .001). At 24-month follow-up, overall survival (surgical aortic valve replacement = 91.3% ± 2.4% vs sutureless = 94.9% ± 2.1% vs transcatheter aortic valve replacement = 79.5% ± 4.3%; P < .001) and survival free from the composite end point of major adverse cardiovascular events and periprosthetic regurgitation were significantly

Stemless Ball Valve

NASA Technical Reports Server (NTRS)

Burgess, Robert K.; Yakos, David; Walthall, Bryan

2012-01-01

This invention utilizes a new method of opening and closing a ball valve. Instead of rotating the ball with a perpendicular stem (as is the case with standard ball valves), the ball is rotated around a fixed axis by two guide pins. This innovation eliminates the leak point that is present in all standard ball valves due to the penetration of an actuation stem through the valve body. The VOST (Venturi Off-Set-Technology) valve has been developed for commercial applications. The standard version of the valve consists of an off-set venturi flow path through the valve. This path is split at the narrowest portion of the venturi, allowing the section upstream from the venturi to be rotated. As this rotation takes place, the venturi becomes restricted as one face rotates with respect to the other, eventually closing off the flow path. A spring-loaded seal made of resilient material is embedded in the upstream face of the valve, making a leak-proof seal between the faces; thus a valve is formed. The spring-loaded lip seal is the only seal that can provide a class six, or bubble-tight, seal against the opposite face of the valve. Tearing action of the seal by high-velocity gas on this early design required relocation of the seal to the downstream face of the valve. In the stemless embodiment of this valve, inner and outer magnetic cartridges are employed to transfer mechanical torque from the outside of the valve to the inside without the use of a stem. This eliminates the leak path caused by the valve stems in standard valves because the stems penetrate through the bodies of these valves.

Validation of the G.LAB MD2200 wrist blood pressure monitor according to the European Society of Hypertension, the British Hypertension Society, and the International Organization for Standardization Protocols.

PubMed

Liu, Ze-Yu; Zhang, Qing-Han; Ye, Xiao-Lei; Liu, Da-Peng; Cheng, Kang; Zhang, Chun-Hai; Wan, Yi

2017-04-01

To validate the G.LAB MD2200 automated wrist blood pressure (BP) monitors according to the European Society of Hypertension International Protocol (ESH-IP) revision 2010, the British Hypertension Society (BHS), and the International Organization for Standardization (ISO) 81060-2:2013 protocols. The device was assessed on 33 participants according to the ESH requirements and was then tested on 85 participants according to the BHS and ISO 81060-2:2013 criteria. The validation procedures and data analysis followed the protocols precisely. The G.LAB MD2200 devices passed all parts of ESH-IP revision 2010 for both systolic and diastolic BP, with a device-observer difference of 2.15±5.51 and 1.51±5.16 mmHg, respectively. The device achieved A/A grading for the BHS protocol and it also fulfilled the criteria of ISO 81060-2:2013, with mean differences of systolic and diastolic BP between the device and the observer of 2.19±5.21 and 2.11±4.70 mmHg, respectively. The G.LAB MD2200 automated wrist BP monitor passed the ESH-IP revision 2010 and the ISO 81060-2:2013 protocol, and achieved the A/A grade of the BHS protocol, which can be recommended for self-measurement in the general population.

British Society of Gastroenterology position statement on serrated polyps in the colon and rectum

PubMed Central

East, James E; Atkin, Wendy S; Bateman, Adrian C; Clark, Susan K; Dolwani, Sunil; Ket, Shara N; Leedham, Simon J; Phull, Perminder S; Rutter, Matt D; Shepherd, Neil A; Tomlinson, Ian; Rees, Colin J

2017-01-01

Serrated polyps have been recognised in the last decade as important premalignant lesions accounting for between 15% and 30% of colorectal cancers. There is therefore a clinical need for guidance on how to manage these lesions; however, the evidence base is limited. A working group was commission by the British Society of Gastroenterology (BSG) Endoscopy section to review the available evidence and develop a position statement to provide clinical guidance until the evidence becomes available to support a formal guideline. The scope of the position statement was wide-ranging and included: evidence that serrated lesions have premalignant potential; detection and resection of serrated lesions; surveillance strategies after detection of serrated lesions; special situations—serrated polyposis syndrome (including surgery) and serrated lesions in colitis; education, audit and benchmarks and research questions. Statements on these issues were proposed where the evidence was deemed sufficient, and re-evaluated modified via a Delphi process until >80% agreement was reached. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) tool was used to assess the strength of evidence and strength of recommendation for finalised statements. Key recommendation: we suggest that until further evidence on the efficacy or otherwise of surveillance are published, patients with sessile serrated lesions (SSLs) that appear associated with a higher risk of future neoplasia or colorectal cancer (SSLs ≥10 mm or serrated lesions harbouring dysplasia including traditional serrated adenomas) should be offered a one-off colonoscopic surveillance examination at 3 years (weak recommendation, low quality evidence, 90% agreement). PMID:28450390

Cardiopulmonary manifestations of isolated pulmonary valve infective endocarditis demonstrated with cardiac CT.

PubMed

Passen, Edward; Feng, Zekun

2015-01-01

Right-sided infective endocarditis involving the pulmonary valve is rare. This pictorial essay discusses the use and findings of cardiac CT combined with delayed chest CT and noncontrast chest CT of pulmonary valve endocarditis. Cardiac CT is able to show the full spectrum of right-sided endocarditis cardiopulmonary features including manifestations that cannot be demonstrated by echocardiography. Copyright © 2015 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

A journey to citizenship: constructions of citizenship and identity in the British Citizenship Test.

PubMed

Gray, Debra; Griffin, Christine

2014-06-01

The British Citizenship Test was introduced in 2005 as one of a raft of new procedures aimed at addressing the perceived problems of integration and social cohesion in migrant communities. In this study, we argue that this new citizenship procedure signals a shift in British political discourse about citizenship - particularly, the institutionalization of a common British citizen identity that is intended to draw citizens together in a new form of political/national community. In line with this, we examine the British Citizenship Test from a social psychological perspective to interrogate the ways in which the test constitutes identity, constitutes citizenship, and constitutes citizenship-as-identity. Analysis of the test and its associated documents highlights three ways in which Britishness-as-identity is constituted, that is, as a collective identity, as a superordinate and national identity, and finally as both a destination and a journey. These findings are discussed in terms of their implications for models of citizenship and models of identity. © 2013 The British Psychological Society.

Tricuspid valve and percutaneous approach: No longer the forgotten valve!

PubMed

Bouleti, Claire; Juliard, Jean-Michel; Himbert, Dominique; Iung, Bernard; Brochet, Eric; Urena, Marina; Dilly, Marie-Pierre; Ou, Phalla; Nataf, Patrick; Vahanian, Alec

2016-01-01

Tricuspid valve disease is mainly represented by tricuspid regurgitation (TR), which is a predictor of poor outcome. TR is usually secondary, caused by right ventricle pressure or volume overload, the leading cause being left-sided heart valve diseases. Tricuspid surgery for severe TR is recommended during left valve surgery, and consists of either a valve replacement or, most often, a tricuspid repair with or without prosthetic annuloplasty. When TR persists or worsens after left valvular surgery, redo isolated tricuspid surgery is associated with high mortality. In addition, a sizeable proportion of patients present with tricuspid surgery deterioration over time, and need a reintervention, which is associated with high morbi-mortality rates. In this context, and given the recent major breakthrough in the percutaneous treatment of aortic and mitral valve diseases, the tricuspid valve appears an appealing challenge, although it raises specific issues. The first applications of transcatheter techniques for tricuspid valve disease were valve-in-valve and valve-in-ring implantation for degenerated bioprosthesis or ring annuloplasty. Some concerns remain regarding prosthesis sizing, rapid ventricular pacing and the best approach, but these procedures appear to be safe and effective. More recently, bicuspidization using a transcatheter approach for the treatment of native tricuspid valve has been published, in two patients. Finally, other devices are in preclinical development. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Depressurization valve

DOEpatents

Skoda, George I.

1989-01-01

A depressurization valve for use in relieving completely the pressure in a simplified boiling water reactor is disclosed. The normally closed and sealed valve is provided with a valve body defining a conduit from an outlet of a manifold from the reactor through a valve seat. A closing valve disk is configured for fitting to the valve seat to normally close the valve. The seat below the disk is provided with a radially extending annulus extending a short distance into the aperture defined by the seat. The disk is correspondingly provided with a longitudinally extending annulus that extends downwardly through the aperture defined by the seat towards the high pressure side of the valve body. A ring shaped membrane is endlessly welded to the seat annulus and to the disk annulus. The membrane is conformed over the confronted surface of the seat and disk in a C-sectioned configuration to seal the depressurization valve against the possibility of weeping. The disk is held to the closed position by an elongate stem extending away from the high pressure side of the valve body. The stem has a flange configured integrally to the stem for bias by two springs. The first spring acts from a portion of the housing overlying the disk on the stem flange adjacent the disk. This spring urges the stem and attached disk away from the seat and thus will cause the valve to open at any pressure. A second spring--preferably of the Belleville variety--acts on a latch plate surrounding and freely moving relative to the end of the stem. This second spring overcomes the bias of the first spring and any pressure acting upon the disk. This Belleville spring maintains through its spring force the valve in the closed position. At the same time, the latch plate with its freedom of movement relative to the stem allows the stem to thermally expand during valve temperature excursion. The latch plate in surrounding the stem is limited in its outward movement by a boss attached to the stem at the end of

Transcatheter JenaValve Implantation in a Stentless Prosthesis: A Challenging Case After 4 Previous Aortic Procedures.

PubMed

Sponga, Sandro; Mazzaro, Enzo; Bagur, Rodrigo; Livi, Ugolino

2017-04-01

A 40-year-old man underwent 4 aortic surgeries because of endocarditis and subsequent prosthesis dehiscence. At the last recurrence he presented with acute severe aortic regurgitation of a Pericarbon Freedom (LivaNova plc, London, UK) stentless bioprosthesis and a morphologically disarranged aortic root. He also presented with left ventricular dysfunction and a very low origin of the left coronary artery. Therefore, a fifth redo aortic valve replacement was considered at high surgical risk. Accordingly, before listing the patient for a heart transplantation, a transcatheter valve-in-valve implantation with the JenaValve (JenaValve Technology, GmbH, Munich, Germany) prosthesis was performed. Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

Excess flow shutoff valve

DOEpatents

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.

England's Class Society in Change.

ERIC Educational Resources Information Center

Rulf, Werner

1990-01-01

Observes that England's present government is displacing the humanist values of traditional higher education with those of a new achievement-oriented society. Points out the educated elite still determines the values of British life. Discusses how these changes affect the working class through a diminished standard of living and quality of…

Absence of posterior tricuspid valve leaflet and valve reconstruction

PubMed Central

Komoda, Takeshi; Stamm, Christof; Fleck, Eckart; Hetzer, Roland

2012-01-01

We report a rare case of the absence of a posterior tricuspid valve leaflet. A male patient, aged 46, suffering from severe tricuspid valve regurgitation (TR) of unknown aetiology and atrial septal aneurysm was referred to our hospital for surgery. On surgical inspection, the posterior tricuspid valve leaflet and its subvalvular apparatus were completely absent and only the valve annulus was seen in the corresponding position. The anterior and septal leaflets were normal. We successfully reconstructed the tricuspid valve as follows: the head of an anterior papillary muscle was approximated to the ventricular septum (Sebening stitch). After the approximation of the centre of the tricuspid annulus of the anterior leaflet to the tricuspid annulus on the opposite side, a sizer of 29 mm in diameter was easily passed through the anterior orifice. The posterior orifice was closed with running sutures (posterior annulorrhaphy after Hetzer). Before these procedures, we attempted to reconstruct the tricuspid valve with a posterior annulorrhaphy alone; however, valve competence was insufficient. A Sebening stitch was necessary to improve the valve competence. Echocardiography showed TR grade 1 at the patient's discharge from hospital and TR grade 1 to 2 at the follow-up, 10 months after the operation. PMID:22419794

Is the mind a cauliflower or an onion? British insights into cognitive organization from the study of abnormal function.

PubMed

McCarthy, R A

2001-02-01

Clinical and normal psychology have had a long tradition of close interaction in British psychology. The roots of this interplay may predate the development of the British Psychological Society, but the Society has encouraged and supported this line of research since its inception. One fundamental British insight has been to consider the evidence from pathology as a potential constraint on theories of normal function. In turn, theories of normal function have been used to understand and illuminate cognitive pathology. This review discusses some of the areas in which clinical contributions to cognitive theory have been most substantial. As with other contributions to this volume, attempts are also made to read the runes and anticipate future developments.

[Percutaneously implantable aortic valve: the JenaValve concept evolution].

PubMed

Figulla, Hans R; Ferrari, Markus

2006-10-01

Due to the increasing incidence of severe aortic stenosis in old and multimorbid patients, the percutaneous implantation of aortic valve-carrying stents has become an alternative to the surgical replacement of aortic valves. Starting in 1995, the authors developed a self-expanding stent which transferred the necessary forces for anchoring up to the aorta ascendens-a conception taken over from CoreValve. The further improvement of this idea over the past 11 years has led to a self-expanding, relatively short stent-valve system that is reliably positioned in the cusps of the old aortic valve and holds the old valve like a paper clip, thus transferring the holding forces physiologically. As compared to conventional systems, the sophisticated insertion catheter requires further chronic animal tests so as to represent a true alternative to the conventional surgical procedure.

Clinical Impact of Diabetes Mellitus on Outcomes After Transcatheter Aortic Valve Replacement: Insights From the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry.

PubMed

Abramowitz, Yigal; Vemulapalli, Sreekanth; Chakravarty, Tarun; Li, Zhuokai; Kapadia, Samir; Holmes, David; Matsouaka, Roland A; Wang, Alice; Cheng, Wen; Forrester, James S; Smalling, Richard; Thourani, Vinod; Mack, Michael; Leon, Martin; Makkar, Raj R

2017-11-01

Diabetes mellitus (DM) adversely affects morbidity and mortality for cardiovascular diseases and procedures. Data evaluating the outcomes of transcatheter aortic valve replacement (TAVR) in diabetic patients are limited by small sample size and contradictory results. We aimed to establish the magnitude of risk and the incremental influence of insulin dependency by examining short- and long-term adverse outcomes according to DM status and therapy in the world's largest TAVR registry. We analyzed data from the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry. In-hospital mortality, 30-day mortality, and 1-year mortality after TAVR in patients with and without DM were evaluated using multivariate modeling. Among 47 643 patients treated with TAVR from November 2011 through September 2015 at 394 US hospitals, there were 17 849 (37.5%) patients with DM. Overall, 6600 of the diabetic patients were insulin treated (IT). Thirty-day mortality was 5.0% in patients with DM (6.1% in IT DM and 4.4% in non-IT DM; P <0.001) versus 5.9% in patients without DM ( P <0.001). Overall, 1-year mortality was 21.8% in patients with DM (24.8% in IT DM and 20.1% in non-IT DM; P <0.001) versus 21.2% in patients without DM ( P =0.274). In a multivariable model, DM was associated with increased 1-year mortality (hazard ratio, 1.30; 95% confidence interval, 1.13-1.49; P <0.001). Subgroup multivariable analysis showed stronger mortality association in IT diabetics (hazard ratio, 1.57; 95% confidence interval, 1.28-1.91; P <0.001) than in non-IT diabetics (hazard ratio, 1.17; 95% confidence interval, 1.00-1.38; P =0.052). Our data establish the magnitude of short- and long-term risk conferred by DM and the incremental risk conferred by insulin dependency in the performance of TAVR. URL: https://www.clinicaltrials.gov. Unique identifier: NCT01737528. © 2017 American Heart Association, Inc.

Murmur intensity in small-breed dogs with myxomatous mitral valve disease reflects disease severity.

PubMed

Ljungvall, I; Rishniw, M; Porciello, F; Ferasin, L; Ohad, D G

2014-11-01

To determine whether murmur intensity in small-breed dogs with myxomatous mitral valve disease reflects clinical and echocardiographic disease severity. Retrospective multi-investigator study. Records of adult dogs Ä20 kg with myxomatous mitral valve disease were examined. Murmur intensity and location were recorded and compared with echocardiographic variables and functional disease status. Murmur intensities in consecutive categories were compared for prevalences of congestive heart failure, pulmonary hypertension and cardiac remodelling. 578 dogs [107 with "soft" (30 Grade I/VI and 77 II/VI), 161 with "moderate" (Grade III/VI), 160 with "loud" (Grade IV/VI) and 150 with "thrilling" (Grade V/VI or VI/VI) murmurs] were studied. No dogs with soft murmurs had congestive heart failure, and 90% had no remodelling. However, 56% of dogs with "moderate", 29% of dogs with "loud" and 8% of dogs with "thrilling" murmurs and subclinical myxomatous mitral valve disease also had no remodelling. Probability of a dog having congestive heart failure or pulmonary hypertension increased with increasing murmur intensity. A 4-level murmur grading scheme separated clinically meaningful outcomes in small-breed dogs with myxomatous mitral valve disease. Soft murmurs in small-breed dogs are strongly indicative of subclinical heart disease. Thrilling murmurs are associated with more severe disease. Other murmurs are less informative on an individual basis. © 2014 British Small Animal Veterinary Association.

Validation of the Pangao PG-800B26 upper arm blood pressure monitor in the general population according to the European Society of Hypertension and the British Hypertension Society protocols.

PubMed

Chen, Liang; Li, Jiyu; Wen, Jing; Guo, Changfeng; Zhang, Jingying; Yu, Zhen

2018-02-01

This study aimed to evaluate the accuracy of the automated oscillometric upper arm blood pressure monitor Pangao PG-800B26 for home blood pressure monitoring according to the European Society of Hypertension International Protocol (ESH-IP) revision 2010 and the British Hypertension Society (BHS) protocols. Systolic and diastolic blood pressures were measured sequentially in 33 and 85 adults, respectively, on the basis of the ESH-IP and BHS protocols using a mercury sphygmomanometer (two observers) and the device (one supervisor). The procedures and analysis methods of the protocols were followed precisely. The device fulfilled the criteria of the ESH-IP, with device-observer differences of 1.01±5.16 and -0.58±4.17 mmHg for systolic and diastolic blood pressure, respectively. Furthermore, the A/A grade of the BHS protocol was also achieved for overall grading and for the three pressure levels, with average differences of 0.85±6.35 and -0.15±5.65 mmHg for systolic and diastolic blood pressure, respectively, which also fulfilled the requirements of the Association for the Advancement of Medical Instrumentation. The Pangao PG-800B26 fulfilled the criteria of the ESH-IP 2010 and achieved the A/A grade of the BHS protocol, and hence can be recommended for home use in adults.

Subvalvular pannus and thrombosis in a mitral valve prosthesis.

PubMed

Kim, Gun Ha; Yang, Dong Hyun; Kang, Joon-Won; Kim, Dae-Hee; Jung, Sung-Ho; Lim, Tae-Hwan

2016-01-01

A 69-year-old female underwent cardiac CT to evaluate prosthetic valve (PHV) dysfunction detected on echocardiography. A CT coronal and en face views of the mitral annular plane showed a low-density, mass-like lesion on the left atrial side of the PHV and a high-density, plate-like lesion on the left ventricular side of PHV. A repeat of the mitral valve replacement was performed, and preoperative CT findings of both the thrombus on the left atrial side and pannus formation on the LV side were confirmed in the operative findings. Copyright © 2016 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

Quickly Removable Valve

NASA Technical Reports Server (NTRS)

Robbins, John S.

1988-01-01

Unit removed with minimal disturbance. Valve inlet and outlet ports adjacent to each other on same side of valve body. Ports inserted into special manifold on fluid line. Valve body attached to manifold by four bolts or, alternatively, by toggle clamps. Electromechanical actuator moves in direction parallel to fluid line to open and close valve. When necessary to clean valve, removed simply by opening bolts or toggle clamps. No need to move or separate ports of fluid line. Valve useful where disturbance of fluid line detrimental or where fast maintenance essential - in oil and chemical industries, automotive vehicles, aircraft, and powerplants.

Ball valve extractor

DOEpatents

Herndon, Charles; Brown, Roger A.

2002-01-01

An apparatus and process for removing a ball valve is provided. The ball valve removal tool provides a handle sliding along the length of a shaft. One end of the shaft is secured within an interior cavity of a ball valve while the opposite end of the shaft defines a stop member. By providing a manual sliding force to the handle, the handle impacts the stop member and transmits the force to the ball valve. The direction of the force is along the shaft of the removal tool and disengages the ball valve from the ball valve housing.

Bellows sealed plug valve

DOEpatents

Dukas, Jr., Stephen J.

1990-01-01

A bellows sealed plug valve includes a valve body having an inlet passage and an outlet passage, a valve chamber between the inlet and outlet passages. A valve plug has substantially the same shape as the valve chamber and is rotatably disposed therein. A shaft is movable linearly in response to a signal from a valve actuator. A bellows is sealingly disposed between the valve chamber and the valve actuator and means are located between the bellows and the valve plug for converting linear movement of the shaft connected to the valve actuator to rotational movement of the plug. Various means are disclosed including helical thread mechanism, clevis mechanism and rack and pinion mechanism, all for converting linear motion to rotational motion.

Check valve installation in pilot operated relief valve prevents reverse pressurization

NASA Technical Reports Server (NTRS)

Oswalt, L.

1966-01-01

Two check valves prevent reverse flow through pilot-operated relief valves of differential area piston design. Title valves control pressure flow to ensure that the piston dome pressure is always at least as great as the main relief valve discharge pressure.

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

PubMed Central

Abulon, Dina Joy; Charles, Martin; Charles, Daniel E

2015-01-01

Purpose 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. PMID:26445520

Microfluidic sieve valves

DOE Office of Scientific and Technical Information (OSTI.GOV)

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.

Transcatheter aortic-valve replacement with a self-expanding prosthesis.

PubMed

Adams, David H; Popma, Jeffrey J; Reardon, Michael J; Yakubov, Steven J; Coselli, Joseph S; Deeb, G Michael; Gleason, Thomas G; Buchbinder, Maurice; Hermiller, James; Kleiman, Neal S; Chetcuti, Stan; Heiser, John; Merhi, William; Zorn, George; Tadros, Peter; Robinson, Newell; Petrossian, George; Hughes, G Chad; Harrison, J Kevin; Conte, John; Maini, Brijeshwar; Mumtaz, Mubashir; Chenoweth, Sharla; Oh, Jae K

2014-05-08

We compared transcatheter aortic-valve replacement (TAVR), using a self-expanding transcatheter aortic-valve bioprosthesis, with surgical aortic-valve replacement in patients with severe aortic stenosis and an increased risk of death during surgery. We recruited patients with severe aortic stenosis who were at increased surgical risk as determined by the heart team at each study center. Risk assessment included the Society of Thoracic Surgeons Predictor Risk of Mortality estimate and consideration of other key risk factors. Eligible patients were randomly assigned in a 1:1 ratio to TAVR with the self-expanding transcatheter valve (TAVR group) or to surgical aortic-valve replacement (surgical group). The primary end point was the rate of death from any cause at 1 year, evaluated with the use of both noninferiority and superiority testing. A total of 795 patients underwent randomization at 45 centers in the United States. In the as-treated analysis, the rate of death from any cause at 1 year was significantly lower in the TAVR group than in the surgical group (14.2% vs. 19.1%), with an absolute reduction in risk of 4.9 percentage points (upper boundary of the 95% confidence interval, -0.4; P<0.001 for noninferiority; P = 0.04 for superiority). The results were similar in the intention-to-treat analysis. In a hierarchical testing procedure, TAVR was noninferior with respect to echocardiographic indexes of valve stenosis, functional status, and quality of life. Exploratory analyses suggested a reduction in the rate of major adverse cardiovascular and cerebrovascular events and no increase in the risk of stroke. In patients with severe aortic stenosis who are at increased surgical risk, TAVR with a self-expanding transcatheter aortic-valve bioprosthesis was associated with a significantly higher rate of survival at 1 year than surgical aortic-valve replacement. (Funded by Medtronic; U.S. CoreValve High Risk Study ClinicalTrials.gov number, NCT01240902.).

A cross-cultural comparison of British and Pakistani medical students' understanding of schizophrenia.

PubMed

Furnham, Adrian; Raja, Nazia; Khan, Umar Ali

2008-06-30

This study aimed to compare British, British Pakistani and Native Pakistani (from Pakistan) medical students' beliefs about the manifestation, causes and cures of schizophrenia, prior to any psychiatric training. A total of 305 participants completed a questionnaire on general beliefs about people with schizophrenia, causal explanations concerning the aetiology of schizophrenia and the role of hospitals and society in treating people with schizophrenia. It was predicted that compared with the British and British Pakistanis, the Pakistanis would have more negative beliefs and attitudes, considering people with schizophrenia to be more dangerous and unpredictable; they were also expected to use more superstitious beliefs to explain the cause of schizophrenia and its symptoms; as well as believe more in seeking help from God and faith healers. There was strong evidence to suggest that Pakistanis possessed more negative beliefs and attitudes about people with schizophrenia, but there was no evidence to indicate that Pakistanis believed more in superstitious causal explanations. Pakistanis were more likely to consider seeking help from faith healers, but not God, compared with British Pakistanis and the British. Results confirm previous European-Asian difference in the understanding of the cause, manifestation and cure of schizophrenia. The impact of traditional and Western cultural influences on British Pakistanis is considered.

Sequential transcatheter aortic valve implantation due to valve dislodgement - a Portico valve implanted over a CoreValve bioprosthesis.

PubMed

Campante Teles, Rui; Costa, Cátia; Almeida, Manuel; Brito, João; Sondergaard, Lars; Neves, José P; Abecasis, João; M Gabriel, Henrique

2017-03-01

Transcatheter aortic valve implantation (TAVI) has become an important treatment in high surgical risk patients with severe aortic stenosis (AS), whose complications need to be managed promptly. The authors report the case of an 86-year-old woman presenting with severe symptomatic AS, rejected for surgery due to advanced age and comorbidities. The patient underwent a first TAVI, with implantation of a Medtronic CoreValve ® , which became dislodged and migrated to the ascending aorta. Due to the previous balloon valvuloplasty, the patient's AS became moderate, and her symptoms improved. After several months, she required another intervention, performed with a St. Jude Portico ® repositionable self-expanding transcatheter aortic valve. There was a good clinical response that was maintained at one-year follow-up. The use of a self-expanding transcatheter bioprosthesis with repositioning features is a solution in cases of valve dislocation to avoid suboptimal positioning of a second implant, especially when the two valves have to be positioned overlapping or partially overlapping each other. Copyright © 2017 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

Problem: Heart Valve Stenosis

MedlinePlus

... valve . Learn about the different types of stenosis: Aortic stenosis Tricuspid stenosis Pulmonary stenosis Mitral stenosis Outlook for ... Disease "Innocent" Heart Murmur Problem: Valve Stenosis - Problem: Aortic Valve Stenosis - Problem: Mitral Valve Stenosis - Problem: Tricuspid Valve Stenosis - ...

Vacuum breaker valve assembly

DOEpatents

Thompson, J.L.; Upton, H.A.

1999-04-27

Breaker valve assemblies for a simplified boiling water nuclear reactor are described. The breaker valve assembly, in one form, includes a valve body and a breaker valve. The valve body includes an interior chamber, and an inlet passage extends from the chamber and through an inlet opening to facilitate transporting particles from outside of the valve body to the interior chamber. The breaker valve is positioned in the chamber and is configured to substantially seal the inlet opening. Particularly, the breaker valve includes a disk which is sized to cover the inlet opening. The disk is movably coupled to the valve body and is configured to move substantially concentrically with respect to the valve opening between a first position, where the disk completely covers the inlet opening, and a second position, where the disk does not completely cover the inlet opening. 1 fig.

Vacuum breaker valve assembly

DOEpatents

Thompson, Jeffrey L.; Upton, Hubert Allen

1999-04-27

Breaker valve assemblies for a simplified boiling water nuclear reactor are described. The breaker valve assembly, in one form, includes a valve body and a breaker valve. The valve body includes an interior chamber, and an inlet passage extends from the chamber and through an inlet opening to facilitate transporting particles from outside of the valve body to the interior chamber. The breaker valve is positioned in the chamber and is configured to substantially seal the inlet opening. Particularly, the breaker valve includes a disk which is sized to cover the inlet opening. The disk is movably coupled to the valve body and is configured to move substantially concentrically with respect to the valve opening between a first position, where the disk completely covers the inlet opening, and a second position, where the disk does not completely cover the inlet opening.

Zero-leak valve

NASA Technical Reports Server (NTRS)

Macglashan, W. F., Jr.

1980-01-01

Zero-leakage valve has fluid-sealing diaphragm support and flat sievelike sealing surface. Diaphragm-support valve is easy to fabricate and requires minimum maintenance. Potential applications include isolation valve for waste systems and remote air-actuated valve. Device is also useful in controlling flow of liquid fluorine and corrosive fluids at high pressures.

Redo aortic valve surgery versus transcatheter valve-in-valve implantation for failing surgical bioprosthetic valves: consecutive patients in a single-center setting

PubMed Central

Wottke, Michael; Deutsch, Marcus-André; Krane, Markus; Piazza, Nicolo; Lange, Ruediger; Bleiziffer, Sabine

2015-01-01

Background Due to a considerable rise in bioprosthetic as opposed to mechanical valve implantations, an increase of patients presenting with failing bioprosthetic surgical valves in need of a reoperation is to be expected. Redo surgery may pose a high-risk procedure. Transcatheter aortic valve-in-valve implantation is an innovative, less-invasive treatment alternative for these patients. However, a comprehensive evaluation of the outcome of consecutive patients after a valve-in-valve TAVI [transcatheter aortic valve-in-surgical aortic valve (TAV-in-SAV)] as compared to a standard reoperation [surgical aortic valve redo-operation (SAV-in-SAV)] has not yet been performed. The goal of this study was to compare postoperative outcomes after TAV-in-SAV and SAV-in-SAV in a single center setting. Methods All SAV-in-SAV and TAV-in-SAV patients from January 2001 to October 2014 were retrospectively reviewed. Patients with previous mechanical or transcatheter valves, active endocarditis and concomitant cardiac procedures were excluded. Patient characteristics, preoperative data, post-procedural complications, and 30-day mortality were collected from a designated database. Mean values ± SD were calculated for all continuous variables. Counts and percentages were calculated for categorical variables. The Chi-square and Fisher exact tests were used to compare categorical variables. Continuous variables were compared using the t-test for independent samples. A 2-sided P value <0.05 was considered statistically significant. Results A total of 102 patients fulfilled the inclusion criteria, 50 patients (49%) underwent a transcatheter valve-in-valve procedure, while 52 patients (51%) underwent redo-surgery. Patients in the TAV-in-SAV group were significantly older, had a higher mean logistic EuroSCORE and exhibited a lower mean left ventricular ejection fraction than patients in the SAV-in-SAV group (78.1±6.7 vs. 66.2±13.1, P<0.001; 27.4±18.7 vs. 14.4±10, P<0.001; and 49.8±13

[Adherence to the recommendations in respiratory rehabilitation of the British Thoracic Society in patients with cystic fibrosis: a study of Colombian physiotherapists].

PubMed

Duran-Palomino, Diana; Chapetón, Olga; Martínez-Santa, Jaime; Campos-Rodríguez, Adriana; Ramírez-Vélez, Robinson

2013-04-01

The aim was to evaluate compliance with the recommendations in respiratory rehabilitation (ReR), raised by the British Thoracic Society (BTS) in patients with cystic fibrosis. A cross-sectional study was conducted in 224 Colombian physiotherapists to identify interventions and components of ReR programs as recommended by the BTS. Interventions with high level of evidence (Grade A) such as: Bronchial Hygiene Therapy (54.0%), and Active Cycle of Breathing Techniques (35.3%) were identified. However, high percentage of physiotherapists practiced interventions with lower grade of recommendation (Grade D) such as: hypertonic saline and bronchodilator to prevent bronchospasm (33.9%), and using manual therapy techniques and thoracic mobility exercises (38.4%) to correct postural and breathing problems. In conclusions we confirm important differences in therapeutic assistant components of the ReR raised by the BTS for patients with cystic fibrosis.

Rotary pneumatic valve

DOEpatents

Hardee, Harry C.

1991-01-01

A rotary pneumatic valve which is thrust balanced and the pneumatic pressure developed produces only radial loads on the valve cylinder producing negligible resistance and thus minimal torque on the bearings of the valve. The valve is multiplexed such that at least two complete switching cycles occur for each revolution of the cylinder spindle.

Scissor thrust valve actuator

DOEpatents

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.

Recellularization of decellularized heart valves: Progress toward the tissue-engineered heart valve

PubMed Central

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

Structural valve deterioration in a starr-edwards mitral caged-disk valve prosthesis.

PubMed

Aoyagi, Shigeaki; Tayama, Kei-Ichiro; Okazaki, Teiji; Shintani, Yusuke; Kono, Michitaka; Wada, Kumiko; Kosuga, Ken-Ichi; Mori, Ryusuke; Tanaka, Hiroyuki

2013-01-01

The durability of the Starr-Edwards (SE) mitral caged-disk valve, model 6520, is not clearly known, and structural valve deterioration in the SE disk valve is very rare. Replacement of the SE mitral disk valve was performed in 7 patients 23-40 years after implantation. Macroscopic examination of the removed disk valves showed no structural abnormalities in 3 patients, in whom the disk valves were removed at <26 years after implantation. Localized disk wear was found at the sites where the disk abutted the struts of the cage, in disk valves excised >36 years after implantation in 4 patients. Disk fracture, a longitudinal split in the disk along its circumference at the site of incorporation of the titanium ring, was detected in the valves removed 36 and 40 years after implantation, respectively, and many cracks were also observed on the outflow aspect of the disk removed 40 years after implantation. Disk fracture and localized disk wear were found in the SE mitral disk valves implanted >36 years previously. The present results suggest that SE mitral caged-disk valves implanted >20 years previously should be carefully followed up, and that those implanted >30 years previously should be electively replaced with modern prosthetic valves

British Society of Interventional Radiology (BSIR) Inferior Vena Cava (IVC) Filter Registry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uberoi, Raman, E-mail: raman.Uberoi@orh.nhs.uk; Tapping, Charles Ross; Chalmers, Nicholas

Purpose: The British Society of Interventional Radiology (BSIR) Inferior Vena Cava (IVC) Filter Registry was produced to provide an audit of current United Kingdom (UK) practice regarding placement and retrieval of IVC filters to address concerns regarding their safety. Methods: The IVC filter registry is a web-based registry, launched by the BSIR on behalf of its membership in October 2007. This report is based on prospectively collected data from October 2007 to March 2011. This report contains analysis of data on 1,434 IVC filter placements and 400 attempted retrievals performed at 68 UK centers. Data collected included patient demographics, insertionmore » and retrieval data, and patient follow-up. Results: IVC filter use in the majority of patients in the UK follows accepted CIRSE guidelines. Filter placement is usually a low-risk procedure, with a low major complication rate (<0.5 %). Cook Gunther Tulip (560 filters: 39 %) and Celect (359 filters: 25 %) filters constituted the majority of IVC filters inserted, with Bard G2, Recovery filters, Cordis Trapease, and OptEase constituting most of the remainder (445 filters: 31 %). More than 96 % of IVC filters deployed as intended. Operator inexperience (<25 procedure) was significantly associated with complications (p < 0.001). Of the IVC filters initially intended for temporary placement, retrieval was attempted in 78 %. Of these retrieval was technically successful in 83 %. Successful retrieval was significantly reduced for implants left in situ for >9 weeks versus those with a shorter dwell time. New lower limb deep vein thrombosis (DVT) and/or IVC thrombosis was reported in 88 patients following filter placement, there was no significant difference of incidence between filter types. Conclusions: This registry report provides interventional radiologists and clinicians with an improved understanding of the technical aspects of IVC filter placement to help improve practice, and the potential consequences of IVC

Aortic valve repair leads to a low incidence of valve-related complications.

PubMed

Aicher, Diana; Fries, Roland; Rodionycheva, Svetlana; Schmidt, Kathrin; Langer, Frank; Schäfers, Hans-Joachim

2010-01-01

Aortic valve replacement for aortic regurgitation (AR) has been established as a standard treatment but implies prosthesis-related complications. Aortic valve repair is an alternative approach, but its mid- to long-term results still need to be defined. Over a 12-year period, 640 patients underwent aortic valve repair for regurgitation of a unicuspid (n=21), bicuspid (n=205), tricuspid (n=411) or quadricuspid (n=3) aortic valve. The mechanism of regurgitation involved prolapse (n=469) or retraction (n=20) of the cusps, and dilatation of the root (n=323) or combined pathologies. Treatment consisted of cusp repair (n=529), root repair (n=323) or a combination of both (n=208). The patients were followed clinically and echocardiographically; follow-up was complete in 98.5% (cumulative follow-up: 3035 patient years). Hospital mortality was 3.4% in the total patient cohort and 0.8% for isolated aortic valve repair. The incidences of thrombo-embolism (0.2% per patient per year) and endocarditis (0.16%per patient per year) were low. Freedom from re-operation at 5 and 10 years was 88% and 81% in bicuspid and 97% and 93% in tricuspid aortic valves (p=0.0013). At re-operation, 13 out of 36 valves could be re-repaired. Freedom from valve replacement was 95% and 90% in bicuspid and 97% and 94% in tricuspid aortic valves (p=0.36). Freedom from all valve-related complications at 10 years was 88%. Reconstructive surgery of the aortic valve is feasible with low mortality in many individuals with aortic regurgitation. Freedom from valve-related complications after valve repair seems superior compared to available data on standard aortic valve replacement. Copyright 2009 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

Valve

DOEpatents

Cho, Nakwon

1980-01-01

A positive acting valve suitable for operation in a corrosive environment is provided. The valve includes a hollow valve body defining an open-ended bore for receiving two, axially aligned, spaced-apart, cylindrical inserts. One insert, designated the seat insert, terminates inside the valve body in an annular face which lies within plane normal to the axis of the two inserts. An elastomeric O-ring seal is disposed in a groove extending about the annular face. The other insert, designated the wedge insert, terminates inside the valve body in at least two surfaces oppositely inclined with respect to each other and with respect to a plane normal to the axis of the two inserts. An elongated reciprocable gate, movable between the two inserts along a path normal to the axis of the two inserts, has a first flat face portion disposed adjacent and parallel to the annular face of the seat insert. The gate has a second face portion opposite to the first face portion provided with at least two oppositely inclined surfaces for mating with respective inclined surfaces of the wedge insert. An opening is provided through the gate which registers with a flow passage through the two inserts when the valve is open. Interaction of the respective inclined surfaces of the gate and wedge insert act to force the first flat face portion of the gate against the O-ring seal in the seat insert at the limits of gate displacement where it reaches its respective fully open and fully closed positions.

Multi-port valve assembly

DOEpatents

Guggenheim, S. Frederic

1986-01-01

A multi-port fluid valve apparatus is used to control the flow of fluids through a plurality of valves and includes a web, which preferably is a stainless steel endless belt. The belt has an aperture therethrough and is progressed, under motor drive and control, so that its aperture is moved from one valve mechanism to another. Each of the valve mechanisms comprises a pair of valve blocks which are held in fluid-tight relationship against the belt. Each valve block consists of a block having a bore through which the fluid flows, a first seal surrounding the bore and a second seal surrounding the first seal, with the distance between the first and second seals being greater than the size of the belt aperture. In order to open a valve, the motor progresses the belt aperture to where it is aligned with the two bores of a pair of valve blocks, such alignment permitting a flow of the fluid through the valve. The valve is closed by movement of the belt aperture and its replacement, within the pair of valve blocks, by a solid portion of the belt.

British Society of Gastroenterology position statement on serrated polyps in the colon and rectum.

PubMed

East, James E; Atkin, Wendy S; Bateman, Adrian C; Clark, Susan K; Dolwani, Sunil; Ket, Shara N; Leedham, Simon J; Phull, Perminder S; Rutter, Matt D; Shepherd, Neil A; Tomlinson, Ian; Rees, Colin J

2017-07-01

Serrated polyps have been recognised in the last decade as important premalignant lesions accounting for between 15% and 30% of colorectal cancers. There is therefore a clinical need for guidance on how to manage these lesions; however, the evidence base is limited. A working group was commission by the British Society of Gastroenterology (BSG) Endoscopy section to review the available evidence and develop a position statement to provide clinical guidance until the evidence becomes available to support a formal guideline. The scope of the position statement was wide-ranging and included: evidence that serrated lesions have premalignant potential; detection and resection of serrated lesions; surveillance strategies after detection of serrated lesions; special situations-serrated polyposis syndrome (including surgery) and serrated lesions in colitis; education, audit and benchmarks and research questions. Statements on these issues were proposed where the evidence was deemed sufficient, and re-evaluated modified via a Delphi process until >80% agreement was reached. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) tool was used to assess the strength of evidence and strength of recommendation for finalised statements. Key recommendation : we suggest that until further evidence on the efficacy or otherwise of surveillance are published, patients with sessile serrated lesions (SSLs) that appear associated with a higher risk of future neoplasia or colorectal cancer (SSLs ≥10 mm or serrated lesions harbouring dysplasia including traditional serrated adenomas) should be offered a one-off colonoscopic surveillance examination at 3 years ( weak recommendation, low quality evidence, 90% agreement ). Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Valve in valve transcatheter aortic valve implantation (ViV-TAVI) versus redo-Surgical aortic valve replacement (redo-SAVR): A systematic review and meta-analysis.

PubMed

Nalluri, Nikhil; Atti, Varunsiri; Munir, Abdullah B; Karam, Boutros; Patel, Nileshkumar J; Kumar, Varun; Vemula, Praveen; Edla, Sushruth; Asti, Deepak; Paturu, Amrutha; Gayam, Sriramya; Spagnola, Jonathan; Barsoum, Emad; Maniatis, Gregory A; Tamburrino, Frank; Kandov, Ruben; Lafferty, James; Kliger, Chad

2018-05-20

Bioprosthetic (BP) valves have been increasingly used for aortic valve replacement over the last decade. Due to their limited durability, patients presenting with failed BP valves are rising. Valve in Valve - Transcatheter Aortic Valve Implantation (ViV-TAVI) emerged as an alternative to the gold standard redo-Surgical Aortic Valve Replacement (redo-SAVR). However, the utility of ViV-TAVI is poorly understood. A systematic electronic search of the scientific literature was done in PubMed, EMBASE, SCOPUS, Google Scholar, and ClinicalTrials.gov. Only studies which compared the safety and efficacy of ViV-TAVI and redo-SAVR head to head in failed BP valves were included. Six observational studies were eligible and included 594 patients, of whom 255 underwent ViV- TAVI and 339 underwent redo-SAVR. There was no significant difference between ViV-TAVI and redo- SAVR for procedural, 30 day and 1 year mortality rates. ViV-TAVI was associated with lower risk of permanent pacemaker implantation (PPI) (OR: 0.43, CI: 0.21-0.89; P = 0.02) and a trend toward increased risk of paravalvular leak (PVL) (OR: 5.45, CI: 0.94-31.58; P = 0.06). There was no significant difference for stroke, major bleeding, vascular complications and postprocedural aortic valvular gradients more than 20 mm-hg. Our results reiterate the safety and feasibility of ViV-TAVI for failed aortic BP valves in patients deemed to be at high risk for surgery. VIV-TAVI was associated with lower risk of permanent pacemaker implantation with a trend toward increased risk of paravalvular leak. © 2018, Wiley Periodicals, Inc.

Force measuring valve assemblies, systems including such valve assemblies and related methods

DOEpatents

DeWall, Kevin George [Pocatello, ID; Garcia, Humberto Enrique [Idaho Falls, ID; McKellar, Michael George [Idaho Falls, ID

2012-04-17

Methods of evaluating a fluid condition may include stroking a valve member and measuring a force acting on the valve member during the stroke. Methods of evaluating a fluid condition may include measuring a force acting on a valve member in the presence of fluid flow over a period of time and evaluating at least one of the frequency of changes in the measured force over the period of time and the magnitude of the changes in the measured force over the period of time to identify the presence of an anomaly in a fluid flow and, optionally, its estimated location. Methods of evaluating a valve condition may include directing a fluid flow through a valve while stroking a valve member, measuring a force acting on the valve member during the stroke, and comparing the measured force to a reference force. Valve assemblies and related systems are also disclosed.

Magnetically operated check valve

NASA Technical Reports Server (NTRS)

Morris, Brian G. (Inventor); Bozeman, Richard J., Jr. (Inventor)

1994-01-01

A magnetically operated check valve is disclosed. The valve is comprised of a valve body and a movable poppet disposed therein. A magnet attracts the poppet to hold the valve shut until the force of fluid flow through the valve overcomes the magnetic attraction and moves the poppet to an unseated, open position. The poppet and magnet are configured and disposed to trap a magnetically attracted particulate and prevent it from flowing to a valve seating region.

Magnetically operated check valve

NASA Astrophysics Data System (ADS)

Morris, Brian G.; Bozeman, Richard J., Jr.

1994-06-01

A magnetically operated check valve is disclosed. The valve is comprised of a valve body and a movable poppet disposed therein. A magnet attracts the poppet to hold the valve shut until the force of fluid flow through the valve overcomes the magnetic attraction and moves the poppet to an unseated, open position. The poppet and magnet are configured and disposed to trap a magnetically attracted particulate and prevent it from flowing to a valve seating region.

Risks and Challenges of Surgery for Aortic Prosthetic Valve Endocarditis.

PubMed

Grubitzsch, Herko; Tarar, Waharat; Claus, Benjamin; Gabbieri, Davide; Falk, Volkmar; Christ, Torsten

2018-03-01

Prosthetic valve endocarditis is the most severe form of infective endocarditis. This study assessed the risks and challenges of surgery for aortic prosthetic valve endocarditis. In total, 116 consecutive patients (98 males, age 65.2±12.7years), who underwent redo-surgery for active aortic prosthetic valve endocarditis between 2000 and 2014, were reviewed. Cox regression analysis was used to identify factors for aortic root destructions as well as for morbidity and mortality. Median follow-up was 3.8 years (0-13.9 years). Aortic root destructions (42 limited and 29 multiple lesions) were associated with early prosthetic valve endocarditis and delayed diagnosis (≥14 d), but not with mortality. There were 16 (13.8%) early (≤30 d) and 32 (27.6%) late (>30 days) deaths. Survival at 1, 5, and 10 years was 72±4.3%, 56±5.4%, and 46±6.4%, respectively. The cumulative incidence of death, reinfection, and reoperation was 19.0% at 30days and 36.2% at 1year. Delayed diagnosis, concomitant procedures, and EuroSCORE II >20% were predictors for early mortality and need for mechanical circulatory support, age >70years, and critical preoperative state were predictors for late mortality. In their absence, survival at 10 years was 70±8.4%. Reinfections and reoperations occurred more frequently if ≥1 risk factor for endocarditis and aortic root destructions were present. At 10 years, freedom from reinfection and reoperation was 89±4.2% and 91±4.0%. The risks of death, reinfection, and reoperation are significant within the first year after surgery for aortic prosthetic valve endocarditis. Early diagnosis and aortic root destructions are the most important challenges, but advanced age, critical preoperative state, and the need for mechanical circulatory support determine long-term survival. Copyright © 2017 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B

Transapical aortic valve implantation without angiography: proof of concept.

PubMed

Ferrari, Enrico; Sulzer, Christopher; Marcucci, Carlo; Rizzo, Elena; Tozzi, Piergiorgio; von Segesser, Ludwig K

2010-06-01

Cardiac computed tomographic scans, coronary angiograms, and aortographies are routinely performed in transcatheter heart valve therapies. Consequently, all patients are exposed to multiple contrast injections with a following risk of nephrotoxicity and postoperative renal failure. The transapical aortic valve implantation without angiography can prevent contrast-related complications. Between November 2008 and November 2009, 30 consecutive high-risk patients (16 female, 53.3%) underwent transapical aortic valve implantation without angiography. The landmarks identification, the stent-valve positioning, and the postoperative control were routinely performed under transesophageal echocardiogram and fluoroscopic visualization without contrast injections. Mean age was 80.1 +/- 8.7 years. Mean valve gradient, aortic orifice area, and ejection fraction were 60.3 +/- 20.9 mm Hg, 0.7 +/- 0.16 cm(2), and 0.526 +/- 0.128, respectively. Risk factors were pulmonary hypertension (60%), peripheral vascular disease (70%), chronic pulmonary disease (50%), previous cardiac surgery (13.3%), and chronic renal insufficiency (40%) (mean blood creatinine and urea levels: 96.8 +/- 54 microg/dL and 8.45 +/- 5.15 mmol/L). Average European System for Cardiac Operative Risk Evaluation was 32.2 +/- 13.3%. Valve deployment in the ideal landing zone was 96.7% successful and valve embolization occurred once. Thirty-day mortality was 10% (3 patients). Causes of death were the following: intraoperative ventricular rupture (conversion to sternotomy), right ventricular failure, and bilateral pneumonia. Stroke occurred in one patient at postoperative day 9. Renal failure (postoperative mean blood creatinine and urea levels: 91.1 +/- 66.8 microg/dL and 7.27 +/- 3.45 mmol/L), myocardial infarction, and atrioventricular block were not detected. Transapical aortic valve implantation without angiography requires a short learning curve and can be performed routinely by experienced teams. Our report

Severe community-acquired pneumonia: use of intensive care services and evaluation of American and British Thoracic Society Diagnostic criteria.

PubMed

Angus, Derek C; Marrie, Thomas J; Obrosky, D Scott; Clermont, Gilles; Dremsizov, Tony T; Coley, Christopher; Fine, Michael J; Singer, Daniel E; Kapoor, Wishwa N

2002-09-01

Despite careful evaluation of changes in hospital care for community-acquired pneumonia (CAP), little is known about intensive care unit (ICU) use in the treatment of this disease. There are criteria that define CAP as "severe," but evaluation of their predictive value is limited. We compared characteristics, course, and outcome of inpatients who did (n = 170) and did not (n = 1,169) receive ICU care in the Pneumonia Patient Outcomes Research Team prospective cohort. We also assessed the predictive characteristics of four prediction rules (the original and revised American Thoracic Society criteria, the British Thoracic Society criteria, and the Pneumonia Severity Index [PSI]) for ICU admission, mechanical ventilation, medical complications, and death (as proxies for severe CAP). ICU patients were more likely to be admitted from home and had more comorbid conditions. Reasons for ICU admission included respiratory failure (57%), hemodynamic monitoring (32%), and shock (16%). ICU patients incurred longer hospital stays (23.2 vs. 9.1 days, p < 0.001), higher hospital costs (21,144 dollars vs. 5,785 dollars, p < 0.001), more nonpulmonary organ dysfunction, and higher hospital mortality (18.2 vs. 5.0%, p < 0.001). Although ICU patients were sicker, 27% were of low risk (PSI Risk Classes I-III). Severity-adjusted ICU admission rates varied across institutions, but mechanical ventilation rates did not. The revised American Thoracic Society criteria rule was the best discriminator of ICU admission and mechanical ventilation (area under the receiver operating characteristic curve, 0.68 and 0.74, respectively) but none of the prediction rules were particularly good. The PSI was the best predictor of medical complications and death (area under the receiver operating characteristic curve, 0.65 and 0.75, respectively), but again, none of the prediction rules were particularly good. In conclusion, ICU use for CAP is common and expensive but admission rates are variable. Clinical

Complete Transversal Disc Fracture in a Björk-Shiley Delrin Mitral Valve Prosthesis 43 Years After Implantation.

PubMed

González-Santos, Jose María; Arnáiz-García, María Elena; Dalmau-Sorlí, María José; Sastre-Rincón, Jose Alfonso; Hernández-Hernández, Jesús; Pérez-Losada, María Elena; Sagredo-Meneses, Víctor; López-Rodríguez, Javier

2016-10-01

A patient who underwent previous implantation of a mitral valve replacement with a Björk-Shiley Delrin (BSD) mitral valve prosthesis during infancy was admitted to our institution 43 years later after an episode of syncope and cardiac arrest. Under extreme hemodynamic instability, a mitral valve prosthetic dysfunction causing massive mitral regurgitation was identified. The patient underwent an emergent cardiac operation, and a complete disc fracture with partial disc migration was found. Exceptional cases of mechanical prosthetic heart valve fracture exist. We report the first case of complete transversal disc rupture of a BSD mitral valve prosthesis after the longest period of implantation ever reported in that position. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

[Validation of the Omron HEM-650 wrist blood pressure device using the British Hypertension Society protocol in emergency patients in Hong Kong].

PubMed

Hung, Kevin KC; Lai, W Y; Cocks, Robert A; Rainer, Timothy H; Graham, Colin A

2015-10-01

Automated wrist cuff blood pressure (BP) devices are more compact and easier to use, particularly when access to the upper arm is restricted, for example in emergencies. We tested the Omron HEM-650 wrist device using the validation criteria of the British Hypertension Society (BHS) protocol in a major emergency department (ED) in Hong Kong. 85 patients had three measurements each by both the Omron HEM-650 wrist device and the mercury sphygmomanometer. The conventional automated BP with arm cuff was also measured using an oscillometric (Colin BP-88S NXT) device for comparison. The Omron HEM-650 achieved a grade B for both systolic and diastolic BP and demonstrated acceptable accuracy and reliability in Chinese patients in the emergency setting. The Omron HEM 650 wrist device can be recommended for use in adult emergency patients. Further research is warranted for its use in pregnant women and critically ill patients.

Automatic shutoff valve

NASA Technical Reports Server (NTRS)

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.

Transcatheter aortic valve-in-valve treatment of degenerative stentless supra-annular Freedom Solo valves: A single centre experience.

PubMed

Cockburn, James; Dooley, Maureen; Parker, Jessica; Hill, Andrew; Hutchinson, Nevil; de Belder, Adam; Trivedi, Uday; Hildick-Smith, David

2017-02-15

Redo surgery for degenerative bioprosthetic aortic valves is associated with significant morbidity and mortality. Report results of valve-in-valve therapy (ViV-TAVI) in failed supra-annular stentless Freedom Solo (FS) bioprostheses, which are the highest risk for coronary occlusion. Six patients with FS valves (mean age 78.5 years, 50% males). Five had valvular restenosis (peak gradient 87.2 mm Hg, valve area 0.63 cm 2 ), one had severe regurgitation (AR). Median time to failure was 7 years. Patients were high risk (mean STS/Logistic EuroScore 10.6 15.8, respectively). FS valves ranged from 21 to 25 mm. Successful ViV-TAVI was achieved in 4/6 patients (67%). Of the unsuccessful cases, (patient 1 and 2 of series) patient 1 underwent BAV with simultaneous aortography which revealed left main stem occlusion. The procedure was stopped and the patient went forward for repeat surgery. Patient 2 underwent successful ViV-TAVI with a 26-mm CoreValve with a guide catheter in the left main, but on removal coronary obstruction occurred, necessitating valve snaring into the aorta. Among the successful cases, (patients 3, 4, 5, 6) the TAVIs used were CoreValve Evolut R 23 mm (n = 3), and Lotus 23 mm (n = 1). In the successful cases the peak gradient fell from 83.0 to 38.3 mm Hg. No patient was left with >1+ AR. One patient had a stroke on Day 2, with full neurological recovery. Two patients underwent semi-elective pacing for LBBB and PR >280 ms. ViV-TAVI in stentless Freedom Solo valves is high risk. The risk of coronary occlusion is high. The smallest possible prosthesis (1:1 sizing) should be used, and strategies to protect the coronary vessels must be considered. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

British Orthodontic Society national audit of temporary anchorage devices (TADs): report of the first thousand TADs placed.

PubMed

Bearn, David R; Alharbi, Fahad

2015-09-01

To provide data from the British Orthodontic Society (BOS) national clinical audit on temporary anchorage device (TAD) use following the recommendations of the National Institute for Health and Clinical Excellence (NIHCE) Design and setting: The Audit commenced on 1 January 2008 and is still ongoing. This article reports the data for TADs placed from 1 January 2008 to 1 November 2013. Audit data was collected from participants using a system of both on-line data entry and hard copy forms. The criteria and standards for the audit were set following the NIHCE report in conjunction with the Development and Standards Committee of the BOS. Virtually all participants used the on-line data entry available on the BOS website. The data submitted was checked and entered manually into an Excel spreadsheet, and transferred to SPSS for analysis. Written information and documented discussion of risks were provided in over 90% of TADs placed, but 17.4% were placed without a specific signed consent form. Temporary anchorage device failure rate was 24.2% overall. Among failed TADs, 93.1% were lost or removed due to excess mobility. Infection or inflammation resulting in loss or removal was reported in 6% of TADs. The only audit standard that was met was failures due to infection of inflammation. The rest of the audit standards were not met. Recommendations are made to address these issues.

Overflow control valve

DOEpatents

Hundal, Rolv; Kessinger, Boyd A.; Parlak, Edward A.

1984-07-24

An overflow control valve for use in a liquid sodium coolant pump tank which valve can be extended to create a seal with the pump tank wall or retracted to break the seal thereby accommodating valve removal. An actuating shaft which controls valve disc position also has cams which bear on roller surfaces to force retraction of a sliding cylinder against spring tension to retract the cylinder from sealing contact with the pump tank.

Aerodynamic Shutoff Valve

NASA Technical Reports Server (NTRS)

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.

Mesofluidic two stage digital valve

DOEpatents

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.

Main Oxidizer Valve Design

NASA Technical Reports Server (NTRS)

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.

Slow opening valve. [valve design for shuttle portable oxygen system

NASA Technical Reports Server (NTRS)

Drapeau, D. F. (Inventor)

1984-01-01

A valve control is described having a valve body with an actuator stem and a rotating handle connected to the actuator stem by a differential drive mechanism which, during uniform movement of the handle in one direction, initially opens the valve at a relatively slow rate and, thereafter, complete the valve movement at a substantially faster rate. A series of stop rings are received about the body in frictional abutting relationship and serially rotated by the handle to uniformly resist handle movement independently of the extent of handle movement.

Validation of the fully automated A&D TM-2656 blood pressure monitor according to the British Hypertension Society Protocol.

PubMed

Zeng, Wei-Fang; Liu, Ming; Kang, Yuan-Yuan; Li, Yan; Wang, Ji-Guang

2013-08-01

The present study aimed to evaluate the accuracy of the fully automated oscillometric upper-arm blood pressure monitor TM-2656 according to the British Hypertension Society (BHS) Protocol 1993. We recruited individuals until there were 85 eligible participants and their blood pressure could meet the blood pressure distribution requirements specified by the BHS Protocol. For each individual, we sequentially measured the systolic and diastolic blood pressures using a mercury sphygmomanometer (two observers) and the TM-2656 device (one supervisor). Data analysis was carried out according to the BHS Protocol. The device achieved grade A. The percentage of blood pressure differences within 5, 10, and 15 mmHg was 62, 85, and 96%, respectively, for systolic blood pressure, and 71, 93, and 99%, respectively, for diastolic blood pressure. The average (±SD) of the device-observer differences was -2.1±7.8 mmHg (P<0.0001) and -1.1±5.8 mmHg (P<0.0001) for systolic and diastolic blood pressures, respectively. The A&D upper-arm blood pressure monitor TM-2656 has passed the requirements of the BHS Protocol, and can thus be recommended for blood pressure measurement.

Repair of Tricuspid Valve Leaflet With CardioCel Patch After Traumatic Tricuspid Regurgitation.

PubMed

Konstantinidou, Maria Kalliopi; Moat, Neil

2017-09-01

Posttraumatic tricuspid valve regurgitation (TR) is a rare entity and is almost always associated with blunt chest trauma. It is usually identified by transthoracic echocardiography after the manifestation of clinical symptoms of heart failure. Treatment varies from long-term medical therapy and observation to surgical correction with tricuspid valve replacement or repair. We describe the case of a 26-year-old man who was involved in a major road traffic accident and was referred for surgical repair a year later because of severe posttraumatic TR. The tricuspid valve was successfully reconstructed with a CardioCel patch, Gore-Tex neochordae, and a tricuspid ring. The patient recovered well. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Lightweight Motorized Valve

NASA Technical Reports Server (NTRS)

Gonzalez, R.; Vandewalle, J.

1986-01-01

Redesigned actuator assembly weighs 50 percent less. Isolator valve operated by ac motor instead of usual dc solenoid. Valve weighs only 3 lb (1.4 kg). New valve functions with either two-phase or three-phase power. Developed for isolating fluids in propellant tanks, manifolds, and interconnecting lines of Space Shuttle reaction control and orbital maneuvering subsystems, valve suited to applications in which leakage must be kept to minimum at high pressure differences - in petroleum and chemical processing.

Cracking a tricuspid perimount bioprosthesis to optimize a second transcatheter sapien valve-in-valve placement.

PubMed

Brown, Stephen C; Cools, Bjorn; Gewillig, Marc

2016-09-01

Bioprosthetic valves degenerate over time. Transcatheter valve-in-valve procedures have become an attractive alternative to surgery. However, every valve increasingly diminishes the diameter of the valvar orifice. We report a 12-year-old female who had a previous transcatheter tricuspid valve-in-valve procedure; cracking the ring of a Carpentier Edwards Perimount valve by means of an ultrahigh pressure balloon allowed implantation of a further larger percutaneous valve. The advantage of this novel approach permits enlarging the inner valve diameter and may facilitate future interventions and prolong time to surgery. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Heart Valve Diseases

MedlinePlus

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 ...

Transfemoral aortic valve implantation in severe aortic stenosis patients with prior mitral valve prosthesis

PubMed Central

Sarı, Cenk; Baştuğ, Serdal; Kasapkara, Hacı Ahmet; Durmaz, Tahir; Keleş, Telat; Akçay, Murat; Aslan, Abdullah Nabi; Bayram, Nihal Akar; Bozkurt, Engin

2015-01-01

Introduction Transcatheter aortic valve implantation for severe symptomatic aortic stenosis in patients with a previous mitral valve prosthesis is technically challenging, and pre-procedural comprehensive assessment of these patients before transcatheter aortic valve implantation is vital for an uncomplicated and successful procedure. Aim We want to share our experience with transcatheter aortic valve implantation in patients with a preexisting functional mitral valve prosthesis and describe a series of important technical and pre-procedural details. Material and methods At our center, 135 patients with symptomatic severe aortic stenosis were treated with transcatheter aortic valve implantation. Six of them with a preexisting mitral valve prosthesis received an Edwards SAPIEN XT valve through the transfemoral route. Results Transcatheter aortic valve implantation was performed successfully in all 6 patients without any deformation of the cobalt-chromium/steel stents of the aortic valve bioprosthesis. Also no distortion or malfunction in the mitral valve prosthesis was observed after the procedure. There were no complications during the hospitalization period. Post-procedural echocardiography revealed no or mild aortic paravalvular regurgitation and normal valve function in all the patients. In addition, serial echocardiographic examination demonstrated that both the stability and function of the aortic and mitral prosthetic valves were normal without any deterioration in the gradients and the degree of the regurgitation at long-term follow-ups. Conclusions Our experience confirms that transcatheter aortic valve implantation is technically feasible in patients with previous mitral valve replacement but comprehensive evaluation of patients by multimodal imaging techniques such as transesophageal echocardiography and multislice computed tomography is mandatory for a successful and safe procedure. PMID:26677380

Kangaroo versus porcine aortic valve tissue--valve geometry morphology, tensile strength and calcification potential.

PubMed

Neethling, W M; Papadimitriou, J M; Swarts, E; Hodge, A J

2000-06-01

Valve related factors and patient related factors are responsible for calcification of valvular bioprostheses. Recent studies showed different donor and recipient species have different influences on the total calcification rate of bioprostheses. This study was performed to evaluate and compare Kangaroo aortic valve leaflets with porcine aortic valve leaflets. Experimental design. Prospective study. Setting. Cardio-thoracic experimental research of a university department. Glutaraldehyde-fixed Kangaroo and porcine valve leaflets were evaluated in vitro according to valve geometry (internal diameter and leaflet thickness), morphology (light and electron microscopy) and tensile strength. In vivo evaluation consisted of implantation in a rat model for 8 weeks, Von Kossa stain for calcium and atomic absorption spectrophotometry for total extractable calcium content. Kangaroo valves indicated a smaller internal valve diameter as well as a thinner valve leaflet (p<0.01, ANOVA) at corresponding body weight, less proteoglycan spicules in the fibrosa, increased elasticity (p<0.05) and low calcification potential (p<0.01, confidence interval 95%). Kangaroo aortic valve leaflets have different valvular qualities compared to porcine valve tissue. Kangaroo valve leaflets are significantly superior to porcine valve leaflets as far as calcification is concerned. These results are encouraging and suggest further in vivo evaluation in a larger animal model before clinical application can be considered.

What Is Heart Valve Surgery?

MedlinePlus

... working correctly. Most valve replacements involve the aortic Tricuspid valve and mitral valves. The aortic valve separates ... where it shouldn’t. This is called incompetence, insufficiency or regurgitation. • Prolapse — mitral valve flaps don’t ...

What Is Heart Valve Disease?

MedlinePlus

... and replacing it with a man-made or biological valve. Biological valves are made from pig, cow, or human ... the valve. Man-made valves last longer than biological valves and usually don’t have to be ...

Valve repair in aortic regurgitation without root dilatation--aortic valve repair.

PubMed

Lausberg, H F; Aicher, D; Kissinger, A; Langer, F; Fries, R; Schäfers, H-J

2006-02-01

Aortic valve repair was established in the context of aortic root remodeling. Variable results have been reported for isolated valve repair. We analyzed our experience with isolated valve repair and compared the results with those of aortic root remodeling. Between October 1995 and August 2003, isolated repair of the aortic valve was performed in 83 patients (REP), remodeling of the aortic valve in 175 patients (REMO). The demographics of the two groups were comparable (REP: mean age 54.4 +/- 20.7 yrs, male-female ratio 2.1 : 1; REMO: mean age 60.8 +/- 13.6 yrs, male-female ratio 2.4 : 1; p = ns). In both groups the number of bicuspid valves was comparable (REP: 41 %, REMO: 32 %; p = ns). All patients were followed by echocardiography for a cumulative follow-up of 8204 patient months (mean 32 +/- 23 months). Overall in-hospital mortality was 2.4 % in REP and 4.6 % in REMO ( p = 0.62). Systolic gradients were comparable in both groups (REP: 5.8 +/- 2.2, REMO: 6.5 +/- 3.1 mm Hg, p = 0.09). The mean degree of aortic regurgitation 12 months postoperatively was 0.8 +/- 0.7 after REP and 0.7 +/- 0.7 after REMO ( p = 0.29). Freedom from significant regurgitation (> or = II degrees ) after 5 years was 86 % in REP and 89 % in REMO ( p = 0.17). Freedom from re-operation after 5 years was 94.4 % in REP and 98.2 % in REMO ( p = 0.33). Aortic regurgitation without concomitant root dilatation can be treated effectively by aortic valve repair. The functional results are equivalent to those obtained with valve-preserving root replacement. Aortic valve repair appears to be an alternative to valve replacement in aortic regurgitation.

Trans-apical aortic valve implantation in patients with severe calcification of the ascending aorta.

PubMed

Buz, Semih; Pasic, Miralem; Unbehaun, Axel; Drews, Thorsten; Dreysse, Stephan; Kukucka, Marian; Mladenow, Alexander; Hetzer, Roland

2011-08-01

In patients with calcification of the ascending aorta, postoperative stroke and mortality rates remain high after conventional aortic valve replacement, but the results of trans-apical aortic valve implantation in these patients are not known. We evaluate the outcome of trans-apical aortic valve implantation in patients with severely calcified ascending aorta in a single center with expanded procedural experience. Between April 2008 and July 2010, 258 patients underwent trans-apical aortic valve implantation using Edwards Sapien valve. By computed tomography (CT) scan, we identified 46 (18%) patients with severe calcification of the ascending aorta (16 with porcelain aorta and 30 with severe, but not complete, calcification). Of 46 patients (mean age 77 ± 10 years, range 63-90 years; EuroSCORE (European System for Cardiac Operative Risk Evaluation) 45 ± 22%; STS (Society of Thoracic Surgeons) score 23 ± 13) with calcified aorta, 15 received 23-mm valves and 31 patients 26-mm valves. Primary valve implantation was successful in 44 patients and a second valve was implanted (valve-in-valve) in two. Six patients underwent concomitant interventions (three elective percutaneous coronary intervention (PCI), one off-pump coronary artery bypass (OPCAB), one tricuspid valve reconstruction, and one left-ventricular (LV) aneurysmectomy). The final procedural results showed valve incompetence (trace or grade 1) in 17 (37%) patients and paravalvular leak in 15 (32.6%) (trace in 10 and grade 1 in five). There was no 30-day mortality. Postoperatively, cranial CT showed new cerebral ischemia areas in three patients (6.2%), but only one patient (2.1%) experienced postoperative neurological deficit (temporary aphasia). Survival at 6 and 12 months was 88% and 85.2%, respectively. Trans-apical aortic valve implantation can be performed safely in patients with aortic valve stenosis and severe calcification of the ascending aorta. Copyright © 2010 European Association for Cardio

Face-Sealing Butterfly Valve

NASA Technical Reports Server (NTRS)

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.

Transapical JenaValve in a patient with mechanical mitral valve prosthesis.

PubMed

O' Sullivan, Katie E; Casserly, Ivan; Hurley, John

2015-04-01

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.

Modeling the Mitral Valve

NASA Astrophysics Data System (ADS)

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.

Magnetically operated check valve

NASA Astrophysics Data System (ADS)

Morris, Brian G.; Bozeman, Richard J., Jr.

1993-03-01

A magnetically operated check valve is disclosed having, in one aspect, a valve body and a movable poppet disposed therein. A magnet attracts the poppet to hold the valve shut until the force of fluid flow through the valve overcomes the magnetic attraction and moves the poppet to an unseated, open position. The poppet and magnet are configured and disposed to trap a magnetically attracted particulate and prevent it from flowing to a valve seating region.

From brain to neuro: the brain research association and the making of British neuroscience, 1965-1996.

PubMed

Abi-Rached, Joelle M

2012-01-01

This article explores the short history of "neuroscience" as a discipline in its own right as opposed to the much longer past of the brain sciences. It focuses on one historical moment, the formation of the first British "neuroscience" society, the Brain Research Association (BRA), renamed in 1996 to the British Neuroscience Association (BNA). It outlines the new thinking brought about by this new science of brain, mind, and behavior, it sketches the beginnings of the BRA and the institutionalization of neuroscience in the British context, and it further explores the ambiguous relation the association had towards some of the ethical, social, and political implications of this new area of research.

Fast acting check valve

NASA Technical Reports Server (NTRS)

Perkins, Gerald S. (Inventor)

1979-01-01

A check valve which closes more rapidly to prevent wearing of the valve seat and of the valve member that seals thereagainst, including a solenoid or other actuator that aids the normal spring to quickly close the valve at approximately the time when downpath fluid flow would stop, the actuator then being deenergized. The control circuit that operates the actuator can include a pair of pressure sensors sensing pressure both upstream and downstream from the valve seat. Where the valve is utilized to control flow to or from a piston pump, energization of the actuator can be controlled by sensing when the pump piston reaches its extreme of travel.

Double-orifice mitral valve associated with bicuspid aortic valve.

PubMed

Khani, Mohammad; Rohani, Atoosheh

2017-06-01

Double-orifice mitral valve is a rare congenital anomaly that usually does not cause a significant hemodynamic effect. Double-orifice mitral valve and a bicuspid aortic valve were detected in a 54-year-old lady who presented with dyspnea on exertion for one year. This is a rare association. Three-dimensional echocardiography is helpful to determine the type of malformation. The patient had no significant mitral regurgitation or stenosis, but demonstrated moderate aortic stenosis. She is undergoing periodic monitoring.

Valve-sparing aortic root replacement in bicuspid aortic valves: a reasonable option?

PubMed

Aicher, Diana; Langer, Frank; Kissinger, Anke; Lausberg, Henning; Fries, Roland; Schäfers, Hans-Joachim

2004-11-01

Aortic dilatation occurs in many patients with bicuspid aortic valves. We have added root replacement using the remodeling technique originally designed for tricuspid aortic valves to bicuspid aortic valve repair for treatment of the dilated root. We compared the results of remodeling in bicuspid aortic valves with those in tricuspid aortic valves. From October 1995 through January 2004, 60 patients underwent root remodeling for bicuspid aortic valves (group A), and 130 patients underwent root remodeling for tricuspid aortic valves (group B). Correction of cusp prolapse was more often performed in group A (group A, 50/60; group B, 47/130; P < .0001). Transthoracic echocardiography was performed at 1 week, 6 and 12 months, and every year thereafter. Cumulative follow-up was 527 patient-years (mean, 2.9 +/- 2 years). No patient died in group A. Hospital mortality in group B was 5% (5/100; 95% confidence interval,1.6%-11.3%) after elective operations and 10% (3/30; 95% confidence interval, 2.1%-26.5%) after emergency operations. Mean systolic gradients were identical at 1 year (group A, 4.8 +/- 2.1 mm Hg; group B, 4.0 +/- 2 mm Hg) and 5 years (group A, 4.5 +/- 2.3 mm Hg; group B, 3.9 +/- 2.2 mm Hg). Freedom from aortic regurgitation of grade 2 or higher at 5 years was 96% in group A and 83% in group B ( P = .07), and freedom from reoperation at 5 years was 98% in group A and 98% in group B ( P = .73). Valve-sparing aortic replacement with root remodeling can be applied to aortic dilatation and a regurgitant bicuspid aortic valve. Hemodynamic function and valve stability of a repaired bicuspid aortic valve are comparable with those seen in cases of tricuspid anatomy.

Remote actuated valve implant

DOE Office of Scientific and Technical Information (OSTI.GOV)

McKnight, Timothy E.; Johnson, Anthony; Moise, Kenneth J.

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.

Valve for fluid control

DOEpatents

Oborny, Michael C.; Paul, Phillip H.; Hencken, Kenneth R.; Frye-Mason, Gregory C.; Manginell, Ronald P.

2001-01-01

A valve for controlling fluid flows. This valve, which includes both an actuation device and a valve body provides: the ability to incorporate both the actuation device and valve into a unitary structure that can be placed onto a microchip, the ability to generate higher actuation pressures and thus control higher fluid pressures than conventional microvalves, and a device that draws only microwatts of power. An electrokinetic pump that converts electric potential to hydraulic force is used to operate, or actuate, the valve.

Recycling of the pulmonary valve: an elegant solution for secondary pulmonary regurgitation in patients with tetralogy of Fallot.

PubMed

Prêtre, René; Rosser, Barbara; Mueller, Christoph; Kretschmar, Oliver; Dave, Hitendu

2012-09-01

The purpose of this study was to review our experience with recycling of the pulmonary valve in cases of chronic pulmonary insufficiency after a transannular patch procedure as part of a repair of tetralogy of Fallot. Eight patients in whom the technique was used were reviewed. Technically, the valve was reapproximated at the anterior commissure if the valve leaflet was sufficiently developed and of good tissue quality. Additional corrections were performed in 5 patients (resection of an infundibular aneurysm [5 patients], repair of the tricuspid valve [1 patient]). The valve was competent with no or trivial regurgitation in 5 patients and a small regurgitation in 3 patients. There was no significant transvalvular gradient in 5 patients with tricuspid valves and a small gradient in 3 patients with a bicuspid valves (<23 mm Hg). The valve function remained stable over the follow-up period (median time, 32 months). Recycling of the pulmonary valve is an interesting concept that could avoid the necessary reoperations linked with valves or valved prostheses. The repair must be carefully followed in bicuspid valves because of a reduction in the opening area. Valve leaflets of good quality should be preserved during the primary repair of tetralogy of Fallot and the transannular incision should be made across the anterior commissure if possible. These steps should allow a few patients to profit from a recycling of their valves in the future. Copyright © 2012 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Solid handling valve

DOEpatents

Williams, William R.

1979-01-01

The present invention is directed to a solids handling valve for use in combination with lock hoppers utilized for conveying pulverized coal to a coal gasifier. The valve comprises a fluid-actuated flow control piston disposed within a housing and provided with a tapered primary seal having a recessed seat on the housing and a radially expandable fluid-actuated secondary seal. The valve seals are highly resistive to corrosion, erosion and abrasion by the solids, liquids, and gases associated with the gasification process so as to minimize valve failure.

Contemporary Costs Associated With Transcatheter Aortic Valve Replacement: A Propensity-Matched Cost Analysis.

PubMed

Ailawadi, Gorav; LaPar, Damien J; Speir, Alan M; Ghanta, Ravi K; Yarboro, Leora T; Crosby, Ivan K; Lim, D Scott; Quader, Mohammed A; Rich, Jeffrey B

2016-01-01

The Placement of Aortic Transcatheter Valve (PARTNER) trial suggested an economic advantage for transcatheter aortic valve replacement (TAVR) for high-risk patients. The purpose of this study was to evaluate the cost effectiveness of TAVR in the "real world" by comparing TAVR with surgical aortic valve replacement (SAVR) in intermediate-risk and high-risk patients. A multiinstitutional database of The Society of Thoracic Surgeons (STS) (2011 to 2013) linked with estimated cost data was evaluated for isolated TAVR and SAVR operations (n = 5,578). TAVR-treated patients (n = 340) were 1:1 propensity matched with SAVR-treated patients (n = 340). Patients undergoing SAVR were further stratified into intermediate-risk (SAVR-IR: predicted risk of mortality [PROM] 4% to 8%) and high-risk (SAVR-HR: PROM >8%) cohorts. Median STS PROM for TAVR was 6.32% compared with 6.30% for SAVR (SAVR-IR 4.6% and SAVR-HR 12.4%). A transfemoral TAVR approach was most common (61%). Mortality was higher for TAVR (10%) compared with SAVR (6%, p < 0.047), whereas the SAVR group accrued higher major morbidity (27% vs 14%, p < 0.001) and longer postoperative hospital duration (7 days vs 6 days, p < 0.001). Importantly, TAVR incurred twice the median total costs compared with SAVR ($69,921 vs $33,598, p < 0.001). The increased cost of TAVR was largely driven by the cost of the valve (all p < 0.001). Intermediate-risk patients undergoing SAVR demonstrated the most exaggerated cost savings versus TAVR. TAVR was associated with greater total costs and mortality compared with SAVR in intermediate-risk and high-risk patients while conferring lower major morbidity and improved resource use. Increased cost of TAVR appears largely related to the cost of the valve. Until the price of TAVR valves decreases, these data suggest that TAVR may not provide the most cost-effective strategy, particularly for intermediate-risk patients. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc

VALVE

DOEpatents

Arkelyan, A.M.; Rickard, C.L.

1962-04-17

A gate valve for controlling the flow of fluid in separate concentric ducts or channels by means of a single valve is described. In one position, the valve sealing discs engage opposed sets of concentric ducts leading to the concentric pipes defining the flow channels to block flow therethrough. In another position, the discs are withdrawn from engagement with the opposed ducts and at the same time a bridging section is interposed therebetween to define concentric paths coextensive with and connecting the opposed ducts to facilitate flow therebetween. A wedge block arrangement is employed with each sealing disc to enable it to engage the ducts. The wedge block arrangement also facilitates unobstructcd withdrawal of the discs out of the intervening space between the sets of ducts. (AEC)

Liquid rocket valve components

NASA Technical Reports Server (NTRS)

1973-01-01

A monograph on valves for use with liquid rocket propellant engines is presented. The configurations of the various types of valves are described and illustrated. Design criteria and recommended practices for the various valves are explained. Tables of data are included to show the chief features of valve components in use on operational vehicles.

Valve assembly for internal combustion engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wakeman, R.J.; Shea, S.F.

1989-09-05

This patent describes an improvement in a valve assembly for an internal combustion engine of the type including a valve having a valve stem, a valve guideway for mounting this valve for reciprocal strokes between opened and seated position, and spring means for biasing the valve into the seated position. The improvement comprising a valve spool of greater cross-sectional diameter as compared to the valve stem, and a valve spool guideway within which the valve spool is movable during the strokes of the valve, an upper surface of the valve spool and a portion of the spool guideway collectively establishingmore » a damper chamber which varies in volume during the valve strokes. a feed passage for introducing oil into the damper chamber, and a bleed passage for discharging oil from the damper chamber. The bleed passages each laterally opening into the valve spool guideway.« less

Transcatheter Aortic Valve Implantation: Experience with the CoreValve Device.

PubMed

Asgar, Anita W; Bonan, Raoul

2012-01-01

The field of transcatheter aortic valve implantation has been rapidly evolving. The Medtronic CoreValve first emerged on the landscape in 2004 with initial first human studies, and it is currently being studied in the Pivotal US trial. This article details the current experience with the self-expanding aortic valve with a focus on clinical results and ongoing challenges. Copyright © 2012 Elsevier Inc. All rights reserved.

Multiple-port valve

DOEpatents

Doody, Thomas J.

1978-08-22

A multiple-port valve assembly is designed to direct flow from a primary conduit into any one of a plurality of secondary conduits as well as to direct a reverse flow. The valve includes two mating hemispherical sockets that rotatably receive a spherical valve plug. The valve plug is attached to the primary conduit and includes diverging passageways from that conduit to a plurality of ports. Each of the ports is alignable wih one or more of a plurality of secondary conduits fitted into one of the hemispherical sockets. The other hemispherical socket includes a slot for the primary conduit such that the conduit's motion along that slot with rotation of the spherical plug about various axes will position the valve-plug ports in respect to the secondary conduits.

Society and the British Army: Implications for Fighting Spirit

DTIC Science & Technology

2017-05-25

5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) U.S. Army Command and General Staff College ATTN: ATZL-SWD-GD Fort...retaining support amongst all segments of society. Failure to do so will negate the cross- fertilization to which Hawley refers. The ethos need not exactly...Geert Hofstede, Gert Jan Hofstede, and Michael Minkov, Cultures and Organizations : Software of the Mind (New York: The McGraw-Hill Companies, 2010

Sliding-gate valve

DOEpatents

Usnick, George B.; Ward, Gene T.; Blair, Henry O.; Roberts, James W.; Warner, Terry N.

1979-01-01

This invention is a novel valve of the slidable-gate type. The valve is designed especially for long-term use with highly abrasive slurries. The sealing surfaces of the gate are shielded by the valve seats when the valve is fully open or closed, and the gate-to-seat clearance is swept with an inflowing purge gas while the gate is in transit. A preferred form of the valve includes an annular valve body containing an annular seat assembly defining a flow channel. The seat assembly comprises a first seat ring which is slidably and sealably mounted in the body, and a second seat ring which is tightly fitted in the body. These rings cooperatively define an annular gap which, together with passages in the valve body, forms a guideway extending normal to the channel. A plate-type gate is mounted for reciprocation in the guideway between positions where a portion of the plate closes the channel and where a circular aperture in the gate is in register with the channel. The valve casing includes opposed chambers which extend outwardly from the body along the axis of the guideway to accommodate the end portions of the gate. The chambers are sealed from atmosphere; when the gate is in transit, purge gas is admitted to the chambers and flows inwardly through the gate-to-seat-ring, clearance, minimizing buildup of process solids therein. A shaft reciprocated by an external actuator extends into one of the sealed chambers through a shaft seal and is coupled to an end of the gate. Means are provided for adjusting the clearance between the first seat ring and the gate while the valve is in service.

Durability of Aortic Valve Cusp Repair With and Without Annular Support.

PubMed

Zeeshan, Ahmad; Idrees, Jay J; Johnston, Douglas R; Rajeswaran, Jeevanantham; Roselli, Eric E; Soltesz, Edward G; Gillinov, A Marc; Griffin, Brian; Grimm, Richard; Hammer, Donald F; Pettersson, Gösta B; Blackstone, Eugene H; Sabik, Joseph F; Svensson, Lars G

2018-03-01

To determine the value of aortic valve repair rather than replacement for valve dysfunction, we assessed late outcomes of various repair techniques in the contemporary era. From January 2001 to January 2011, aortic valve repair was planned in 1,124 patients. Techniques involved commissural figure-of-8 suspension sutures (n = 63 [6.2%]), cusp repair with commissuroplasty (n = 481 [48%]), debridement (n = 174 [17%]), free-margin plication (n = 271 [27%]) or resection (n = 75) or both, or annulus repair with resuspension (n = 230 [23%]), root reimplantation (n = 252 [25%]), or remodeling (n = 35 [3.5%]). Planned repair was aborted for replacement in 115 patients (10%); risk factors included greater severity of aortic regurgitation (AR; p = 0.0002) and valve calcification (p < 0.0001). In-hospital outcomes for the remaining 1,009 patients included death (12 [1.2%]), stroke (13 [1.3%]), and reoperation for valve dysfunction (14 [1.4%]). Freedom from aortic valve reoperation at 1, 5, and 10 years was 97%, 93%, and 90%, respectively. Figure-of-8 suspension sutures, valve resuspension, and root repair and replacement were least likely to require reoperation; cusp repair with commissural sutures, plication, and commissuroplasty was most likely (p < 0.05). Survival at 1, 5, and 10 years was 96%, 92%, and 83%. Immediate postoperative AR grade was none-mild (94%), moderate (5%), and severe (1%). At 10 years after repair, AR grade was none (20%), mild (33%), moderate (26%), and severe (21%). Patients undergoing root procedures were less likely to have higher-grade postoperative AR (p < 0.0001). Valve repair is effective and durable for treating aortic valve dysfunction. Greater severity of AR preoperatively is associated with higher likelihood of repair failure. Commissural figure-of-8 suspension sutures and repair with annular support have the best long-term durability. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights

The Pattern of History of Psychology Teaching on British Undergraduate Psychology Courses

ERIC Educational Resources Information Center

Richards, Graham

2005-01-01

Teaching of History of Psychology is likely to become increasingly important as the British Psychological Society's 2002 guidelines for approved undergraduate courses are implemented. Results of a survey of History of Psychology teaching during the academic year 1999-2000 are summarised and discussed in the light of these new requirements. While…

Solenoid Valve With Self-Compensation

NASA Technical Reports Server (NTRS)

Woeller, Fritz H.; Matsumoto, Yutaka

1987-01-01

New solenoid-operated miniature shutoff valve provides self-compensation of differential pressure forces that cause jamming or insufficient valve closure as in single-seal valves. Dual-seal valve is bidirectional. Valve simultaneously seals both inlet and outlet tubes by pressing single disk of silicone rubber against ends of both.

One-year multicentre outcomes of transapical aortic valve implantation using the SAPIEN XT™ valve: the PREVAIL transapical study.

PubMed

Walther, Thomas; Thielmann, Matthias; Kempfert, Joerg; Schroefel, Holger; Wimmer-Greinecker, Gerhard; Treede, Hendrik; Wahlers, Thorsten; Wendler, Olaf

2013-05-01

The study aimed to evaluate 1-year outcomes of the multicentre PREVAIL transapical (TA) study of TA-aortic valve implantation (AVI) in high-risk patients. From September 2009 to August 2010, a total of 150 patients, aged 81.6 ± 5.8 years, 40.7% female, were included at 12 European TA-AVI experienced sites. Patients received 23 (n = 36), 26 (n = 57) and 29 mm (n = 57) second-generation SAPIEN XT™ (Edwards Lifesciences, Irvine, CA, USA) valves. The mean logistic EuroSCORE was 24.3 ± 7.0, and mean Society Thoracic Surgeons score was 7.5 ± 4.4%. Survival was 91.3% at 30 days and 77.9% at 1 year. Subgroup analysis revealed survivals of 91.7/88.9, 86.0/70.2, 96.55/91.2% for patients receiving 23-, 26- and 29-mm valves at 30 days and at 1 year, respectively. Transthoracic echocardiography revealed preserved left ventricular ejection fraction and low gradients. Aortic incompetence was none in 41/48, trace 30/36, mild 22/12 and moderate in 7/4% at discharge and 1 year. Walking distance increased from 221 (postimplant) to 284 m (at 1 year, P = 0.0004). Three patients required reoperation due to increasing aortic incompetence during follow-up. Causes of mortality at 1 year were cardiac (n = 7), stroke (n = 1) and others (n = 5). The European PREVAIL multicentre trial demonstrates good functionality and good outcomes for TA-AVI using the second-generation SAPIEN XT prosthesis and the ASCENDRA-II delivery system. The 29-mm SAPIEN XT valve was successfully introduced and showed excellent results.

Disability, Higher Education and the Inclusive Society

ERIC Educational Resources Information Center

Barnes, Colin

2007-01-01

Much has changed over recent years with regard to disability and higher education. Until the 1990s, most British universities were virtually inaccessible to disabled students and staff. However, as society move ever further into the twenty-first century there are more disabled students in higher education, more support services for students with…

Study of multiple cycles valves

NASA Technical Reports Server (NTRS)

Wichmann, H.

1973-01-01

A discussion is presented regarding valves which can be cycled repeatedly and are available from industry for application in the inlet system for the Pioneer Venus Probe mass spectrometer. Both solenoid type and latching type valves are considered. The study is divided into two principal areas: (1) preparation of a valve specification reflecting the requirements of the inlet system cyclic valves for the Pioneer Venus Probe mass spectrometer and the submittal of this specification to potential valve suppliers for their response and proposal; (2) preparation of a design layout of an optimum cyclic valve meeting all of the valve specification requirements.

Cultural and age differences in beliefs about depression: British Bangladeshis vs. British Whites

PubMed Central

McClelland, Alastair; Khanam, Shopnara; Furnham, Adrian

2013-01-01

This study examines beliefs about depression as a function of ethnic background (British Bangladeshis vs. British Whites) and age. A total of 364 participants completed a 65-item questionnaire, containing general questions regarding depression and anti-depressive behaviour; the causes of depression, and treatments for depression. The hypotheses were broadly supported; there were significant interactions between ethnicity and age, which generally revealed an increasingly negative attitude towards depression with increasing age amongst British Bangladeshis. Older British Bangladeshis believed depression was an illness that brought a sense of shame and loss of dignity to the individual and his or her family, and they also favoured a lay referral system for sufferers. They also had more superstitious beliefs about depression than both younger British Bangladeshis and British Whites. A pattern of increasing negativity with increasing age was not evident amongst the British Whites, but older individuals in both groups tended to believe that depression was not helped by psychological intervention. The attitudes towards depression in the young was similar (and generally positive) in both ethnic groups. These findings highlight the necessity to provide more culturally sensitive and accessible services for migrant communities – particularly amongst older individuals. PMID:25076835

Magnetic Check Valve

NASA Technical Reports Server (NTRS)

Morris, Brian G.; Bozeman, Richard J., Jr.

1994-01-01

Poppet in proposed check valve restored to closed condition by magnetic attraction instead of spring force. Oscillations suppressed, with consequent reduction of wear. Stationary magnetic disk mounted just upstream of poppet, also containing magnet. Valve body nonmagnetic. Forward pressure or flow would push poppet away from stationary magnetic disk so fluid flows easily around poppet. Stop in valve body prevents poppet from being swept away. When flow stopped or started to reverse, magnetic attraction draws poppet back to disk. Poppet then engages floating O-ring, thereby closing valve and preventing reverse flow. Floating O-ring facilitates sealing at low loads.

Mitral valve replacement with the Hancock stabilized glutaraldehyde valve. Clinical and laboratory evaluation.

PubMed

Buch, W S; Pipkin, R D; Hancock, W D; Fogarty, T J

1975-11-01

From March 1971 through April 1975, one hundred twenty patients underwent mitral valve replacement with a Hancock "stabilized glutaraldehyde process" porcine aortic xenograft. A simultaneous canine experimental series was also carried out. In the clinical series, the early mortality was 8.3%. Actuarial analyses of all patients predicts survival at two years of 81.0% and at four years of 70.0%. The predicted survival for patients without coronary disease or prior prosthetic valve replacement is 87.5% at two years and 77.5% at four years. There were four thromboembolic episodes, a rate of 2.4% per patient-year. None were fatal. No valve failure were noted. Histologic examination and shrink temperature analysis of recovered valves show excellent tissue preservation at 40 months. The data indicate that the Hancock valve is durable, enjoys a low incidence of thromboembolism, and may be the valve of choice for mitral valve replacement.

Discourses of smoking, health, and the just society: yesterday, today, and the return of the same?

PubMed

Palladino, P

2001-08-01

This paper locates the political impact of Bernie Ecclestone's controversial donation to the Labour Party, just before its election to government in 1997, in a recurrent concern among British socialists about the relationship between smoking, health, and the just society. It does so by turning to an earlier episode in the history of British socialism, specifically to Horace Joules' political agitation from 1951 onward, within the Socialist Medical Association, advisory committees to the Ministry of Health, and the British popular and medical press, for government action against smoking. The argument is that the association of concerns over smoking, health and the making of a just society is rooted in aspirations to Christian community that were and continue to be fundamentally important in the development of British socialism. Smoking has been viewed and continues to be viewed as incompatible with this understanding of community because it is the ultimate consumer good, refractory to any discourse of utility and responsibility.

Anterior mitral valve aneurysm: a rare sequelae of aortic valve endocarditis.

PubMed

Janardhanan, Rajesh; Kamal, Muhammad Umar; Riaz, Irbaz Bin; Smith, M Cristy

2016-03-01

SummaryIn intravenous drug abusers, infective endocarditis usually involves right-sided valves, with Staphylococcus aureus being the most common etiologic agent. We present a patient who is an intravenous drug abuser with left-sided (aortic valve) endocarditis caused by Enterococcus faecalis who subsequently developed an anterior mitral valve aneurysm, which is an exceedingly rare complication. A systematic literature search was conducted which identified only five reported cases in the literature of mitral valve aneurysmal rupture in the setting of E. faecalis endocarditis. Real-time 3D-transesophageal echocardiography was critical in making an accurate diagnosis leading to timely intervention. Early recognition of a mitral valve aneurysm (MVA) is important because it may rupture and produce catastrophic mitral regurgitation (MR) in an already seriously ill patient requiring emergency surgery, or it may be overlooked at the time of aortic valve replacement (AVR).Real-time 3D-transesophageal echocardiography (RT-3DTEE) is much more advanced and accurate than transthoracic echocardiography for the diagnosis and management of MVA. © 2016 The authors.

Transcatheter Mitral Valve Replacement for Native and Failed Bioprosthetic Mitral Valves

PubMed Central

Sarkar, Kunal; Reardon, Michael J.; Little, Stephen H.; Barker, Colin M.; Kleiman, Neal S.

2017-01-01

Transcatheter mitral valve replacement (TMVR) is a novel approach for treatment of severe mitral regurgitation. A number of TMVR devices are currently undergoing feasibility trials using both transseptal and transapical routes for device delivery. Overall experience worldwide is limited to fewer than 200 cases. At present, the 30-day mortality exceeds 30% and is attributable to both patient- and device-related factors. TMVR has been successfully used to treat patients with degenerative mitral stenosis (DMS) as well as failed mitral bioprosthesis and mitral repair using transcatheter mitral valve-in-valve (TMViV)/valve-in-ring (ViR) repair. These patients are currently treated with devices designed for transcatheter aortic valve replacement. Multicenter registries have been initiated to collect outcomes data on patients currently undergoing TMViV/ViR and TMVR for DMS and have confirmed the feasibility of TMVR in these patients. However, the high periprocedural and 30-day event rates underscore the need for further improvements in device design and multicenter randomized studies to delineate the role of these technologies in patients with mitral valve disease. PMID:29743999

Fast acting multiple element valve

DOEpatents

Yang, Jefferson Y. S.; Wada, James M.

1991-01-01

A plurality of slide valve elements having plural axial-spaced annular parts and an internal slide are inserted into a bulkhead in a fluid conduit from a downstream side of the bulkhead, locked in place by a bayonet coupling and set screw, and project through the bulkhead into the upstream conduit. Pneumatic lines connecting the slide valve element actuator to pilot valves are brought out the throat of the valve element to the downstream side. Pilot valves are radially spaced around the exterior of the valve to permit the pneumatic lines to be made identical, thereby to minimize adverse timing tolerances in operation due to pressure variations. Ring manifolds surround the valve adjacent respective pilot valve arrangements to further reduce adverse timing tolerances due to pressure variations, the manifolds being directly connected to the respective pilot valves. Position sensors are provided the valve element slides to signal the precise time at which a slide reaches or passes through a particular point in its stroke to initiate a calibrated timing function.

Conical Seat Shut-Off Valve

NASA Technical Reports Server (NTRS)

Farner, Bruce

2013-01-01

A moveable valve for controlling flow of a pressurized working fluid was designed. This valve consists of a hollow, moveable floating piston pressed against a stationary solid seat, and can use the working fluid to seal the valve. This open/closed, novel valve is able to use metal-to-metal seats, without requiring seat sliding action; therefore there are no associated damaging effects. During use, existing standard high-pressure ball valve seats tend to become damaged during rotation of the ball. Additionally, forces acting on the ball and stem create large amounts of friction. The combination of these effects can lead to system failure. In an attempt to reduce damaging effects and seat failures, soft seats in the ball valve have been eliminated; however, the sliding action of the ball across the highly loaded seat still tends to scratch the seat, causing failure. Also, in order to operate, ball valves require the use of large actuators. Positioning the metal-to-metal seats requires more loading, which tends to increase the size of the required actuator, and can also lead to other failures in other areas such as the stem and bearing mechanisms, thus increasing cost and maintenance. This novel non-sliding seat surface valve allows metal-to-metal seats without the damaging effects that can lead to failure, and enables large seating forces without damaging the valve. Additionally, this valve design, even when used with large, high-pressure applications, does not require large conventional valve actuators and the valve stem itself is eliminated. Actuation is achieved with the use of a small, simple solenoid valve. This design also eliminates the need for many seals used with existing ball valve and globe valve designs, which commonly cause failure, too. This, coupled with the elimination of the valve stem and conventional valve actuator, improves valve reliability and seat life. Other mechanical liftoff seats have been designed; however, they have only resulted in

Fast-acting valve and uses thereof

DOEpatents

Meyer, J.A.

1980-05-16

A very fast acting valve capable of producing a very well-defined plug of gas suitable for filling a theta pinch vacuum vessel is given. The valve requires no springs, instead being stopped mainly by a nonlinear force. Thus, the valve is not subject to bouncing; and the ratio of the size of the valve housing to the size of the valve stem is smaller than it would be if springs were needed to stop the valve stem. Furthermore, the valve can be used for thousands of valve firings with no apparent valve damage.

Fast-acting valve and uses thereof

DOEpatents

Meyer, James A.

1982-01-01

A very fast acting valve capable of producing a very well-defined plug of gas suitable for filling a theta pinch vacuum vessel is given. The valve requires no springs, instead being stopped mainly by a nonlinear force. Thus, the valve is not subject to bouncing; and the ratio of the size of the valve housing to the size of the valve stem is smaller than it would be if springs were needed to stop the valve stem. Furthermore, the valve can be used for thousands of valve firings with no apparent valve damage.

The prognosis of infective endocarditis treated with biological valves versus mechanical valves: A meta-analysis.

PubMed

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

The prognosis of infective endocarditis treated with biological valves versus mechanical valves: A meta-analysis

PubMed Central

Tao, Ende; Wan, Li; Wang, WenJun; Luo, YunLong; Zeng, JinFu; Wu, Xia

2017-01-01

Objective 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. Methods 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. Results 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). Conclusion 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

Heart valve surgery - series (image)

MedlinePlus

... heart valves are either natural (biologic) or artificial (mechanical). Natural valves are from human donors (cadavers), modified ... artificial valves will require anticoagulation. The advantage of mechanical valves is that they last longer-thus, the ...

Valve Repair or Replacement

MedlinePlus

... called anticoagulants) for the rest of their lives. Biological valves are made from animal tissue (called a ... for valve replacement (called an autograft). Patients with biological valves usually do not need to take blood- ...

Fluid mechanics of heart valves.

PubMed

Yoganathan, Ajit P; He, Zhaoming; Casey Jones, S

2004-01-01

Valvular heart disease is a life-threatening disease that afflicts millions of people worldwide and leads to approximately 250,000 valve repairs and/or replacements each year. Malfunction of a native valve impairs its efficient fluid mechanic/hemodynamic performance. Artificial heart valves have been used since 1960 to replace diseased native valves and have saved millions of lives. Unfortunately, despite four decades of use, these devices are less than ideal and lead to many complications. Many of these complications/problems are directly related to the fluid mechanics associated with the various mechanical and bioprosthetic valve designs. This review focuses on the state-of-the-art experimental and computational fluid mechanics of native and prosthetic heart valves in current clinical use. The fluid dynamic performance characteristics of caged-ball, tilting-disc, bileaflet mechanical valves and porcine and pericardial stented and nonstented bioprostheic valves are reviewed. Other issues related to heart valve performance, such as biomaterials, solid mechanics, tissue mechanics, and durability, are not addressed in this review.

Intelligent Flow Control Valve

NASA Technical Reports Server (NTRS)

Kelley, Anthony R (Inventor)

2015-01-01

The present invention is an intelligent flow control valve which may be inserted into the flow coming out of a pipe and activated to provide a method to stop, measure, and meter flow coming from the open or possibly broken pipe. The intelligent flow control valve may be used to stop the flow while repairs are made. Once repairs have been made, the valve may be removed or used as a control valve to meter the amount of flow from inside the pipe. With the addition of instrumentation, the valve may also be used as a variable area flow meter and flow controller programmed based upon flowing conditions. With robotic additions, the valve may be configured to crawl into a desired pipe location, anchor itself, and activate flow control or metering remotely.

How to Make a Heart Valve: From Embryonic Development to Bioengineering of Living Valve Substitutes

PubMed Central

MacGrogan, Donal; Luxán, Guillermo; Driessen-Mol, Anita; Bouten, Carlijn; Baaijens, Frank; de la Pompa, José Luis

2014-01-01

Cardiac valve disease is a significant cause of ill health and death worldwide, and valve replacement remains one of the most common cardiac interventions in high-income economies. Despite major advances in surgical treatment, long-term therapy remains inadequate because none of the current valve substitutes have the potential for remodeling, regeneration, and growth of native structures. Valve development is coordinated by a complex interplay of signaling pathways and environmental cues that cause disease when perturbed. Cardiac valves develop from endocardial cushions that become populated by valve precursor mesenchyme formed by an epithelial–mesenchymal transition (EMT). The mesenchymal precursors, subsequently, undergo directed growth, characterized by cellular compartmentalization and layering of a structured extracellular matrix (ECM). Knowledge gained from research into the development of cardiac valves is driving exploration into valve biomechanics and tissue engineering directed at creating novel valve substitutes endowed with native form and function. PMID:25368013

Outcomes following transcatheter aortic valve replacement in patients with native aortic valve regurgitation

PubMed Central

Bob-Manuel, Tamunoinemi; Kadire, Siri; Heckle, Mark R.; Wang, Jiajing

2018-01-01

Due to the absence of annular calcification for device anchoring, it is presumed that transcatheter aortic valve replacement (TAVR) is not suitable for the treatment of native aortic valve regurgitation (NAVR) resulting in very limited data and experience concerning its safety and efficacy. We sought to review published data on the safety and efficacy of TAVR in high-risk patients with NAVR. Studies including case reports, case series and original articles published between 2002 and 2016 on TAVR in patients with NAVR were identified with a systematic electronic search using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Only studies reporting data on demographic and procedural characteristics, management and follow up outcomes were analyzed. A total of 30 publications describing 182 patients were identified. Most patients (54%) were men, with a mean age of 70.1±2.6 years, mean logistic European System for Cardiac Operative Risk Evaluation score (EuroSCORE) of 21.8%±4.5% and mean Society of Thoracic Surgeons (STS) score of 8%±1.8% for mortality. The majority (87%) of patients had severe NAVR with no valvular calcification. TAVR was mostly performed through the femoral (58.8%) and apical (33.1%) approach. Device success, defined by VARC-2, was achieved in 86.3% of our study population. A second valve was required in 17 patients (9.3%) during the index procedure for residual aortic regurgitation or malposition. Post-procedure aortic regurgitation of grade 1 or less was present in 80 patients (81%). Pacemaker implantation was required post procedure in 17 patients (9.3%). The 30-day and 1-year mortality was 11.9% and 16.2%, respectively. TAVR is associated with favorable pacemaker implantation and 1-year mortality rates with a high 30-day mortality among selected patients with NAVR. PMID:29404354

Locking apparatus for gate valves

DOEpatents

Fabyan, J.; Williams, C.W.

A locking apparatus for fluid operated valves having a piston connected to the valve actuator which moves in response to applied pressure within a cylinder housing having a cylinder head, a catch block is secured to the piston, and the cylinder head incorporates a catch pin. Pressure applied to the cylinder to open the valve moves the piston adjacent to the cylinder head where the catch pin automatically engages the catch block preventing further movement of the piston or premature closure of the valve. Application of pressure to the cylinder to close the valve, retracts the catch pin, allowing the valve to close. Included are one or more selector valves, for selecting pressure application to other apparatus depending on the gate valve position, open or closed, protecting such apparatus from damage due to premature closing caused by pressure loss or operational error.

Long life valve design concepts

NASA Technical Reports Server (NTRS)

Jones, J. R.; Hall, A. H., Jr.

1975-01-01

Valve concept evaluation, final candidate selection, design, manufacture, and demonstration testing of a pneumatically actuated 10-inch hybrid poppet butterfly shutoff valve are presented. Conclusions and recommendations regarding those valve characteristics and features which would serve to guide in the formulation of future valve procurements are discussed. The pertinent design goals were temperature range of plus 200 to minus 423 F, valve inlet pressure 35 psia, actuation pressure 750 psia, main seal leakage 3 x 0.00001 sccs at 35 psia valve inlet pressure, and a storage and operating life of 10 years. The valve was designed to be compatible with RP-1, propane, LH2, LO2, He, and N2.

The Double-Orifice Valve Technique to Treat Tricuspid Valve Incompetence.

PubMed

Hetzer, Roland; Javier, Mariano; Delmo Walter, Eva Maria

2016-01-01

A straightforward tricuspid valve (TV) repair technique was used to treat either moderate or severe functional (normal valve with dilated annulus) or for primary/organic (Ebstein's anomaly, leaflet retraction/tethering and chordal malposition/tethering, with annular dilatation) TV incompetence, and its long-term outcome assessed. A double-orifice valve technique was employed in 91 patients (mean age 52.6 ± 23.2 years; median age 56 years; range: 0.6-82 years) with severe tricuspid regurgitation. Among the patients, three had post-transplant iatrogenic chordal rupture, five had infective endocarditis, 11 had mitral valve insufficiency, 23 had Ebstein's anomaly, and 47 had isolated severe TV incompetence. The basic principle was to reduce the distance between the coapting leaflets, wherein the most mobile leaflet could coapt to the opposite leaflet, by creating two orifices, ensuring valve competence. The TV repair was performed through a median sternotomy or right anterior thoracotomy in the fifth intercostal space under cardiopulmonary bypass. The degree and extent of creating a double-valve orifice was determined by considering the minimal body surface area (BSA)-related acceptable TV diameter. Repair was accomplished by passing pledgeted mattress sutures from the middle of the true anterior annulus to a spot on the opposite septal annulus, located approximately two-thirds of the length of the septal annulus to avoid injury to the bundle of His. The annular apposition divides the TV into a larger anterior and a smaller posterior orifices, enabling valve closure, on both sides. In adults, the diameter of the anterior valve orifice should be 23-25 mm, and the posterior orifice 15-18 mm; thus, the total valve orifice area is 5-6 cm2. In children, the total valve orifice should be a standard deviation of 1.7 mm for a BSA of <1. 0m2, and 1.5 mm for a BSA of >1.0m2. During a mean follow up of 8.7 ± 1.34 years (median 10 years; range: 1.5-25.9 years) there have been no

Compact valve actuation mechanism

NASA Technical Reports Server (NTRS)

Brogdon, James William (Inventor); Gill, David Keith (Inventor)

2000-01-01

A valve actuation device. The device may include a free floating valve bridge movably supported within a cavity in the engine housing. The bridge may be provided with a cavity and an orifice arrangement for pumping gases entrained with lubricating fluid toward the piston stems as the bridge reciprocates back and forth. The device may also include a rocker arm that has a U-shaped cross-sectional shape for receiving at least a portion of the valve bridge, valve stem valve spring and spring retainer therein. The rocker arm may be provided with lubrication passages for directing lubrication to the point wherein it is pivotally affixed to the engine housing.

FLUID MECHANICS OF ARTIFICIAL HEART VALVES

PubMed Central

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

2009-01-01

SUMMARY 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. PMID:19220329

Fluid mechanics of artificial heart valves.

PubMed

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.

Valve technology: A compilation

NASA Technical Reports Server (NTRS)

1971-01-01

A technical compilation on the types, applications and modifications to certain valves is presented. Data cover the following: (1) valves that feature automatic response to stimuli (thermal, electrical, fluid pressure, etc.), (2) modified valves changed by redesign of components to increase initial design effectiveness or give the item versatility beyond its basic design capability, and (3) special purpose valves with limited application as presented, but lending themselves to other uses with minor changes.

Acute obstruction by Pannus in patients with aortic medtronic-hall valves: 30 years of experience.

PubMed

Ellensen, Vegard Skalstad; Andersen, Knut Sverre; Vitale, Nicola; Davidsen, Einar Skulstad; Segadal, Leidulf; Haaverstad, Rune

2013-12-01

Acute dysfunction of mechanical aortic valve prostheses is a life-threatening adverse event. Pannus overgrowth, which is fibroelastic hyperplasia originating from the periannular area, is one cause of dysfunction. The aim of this study was to determine the annual incidence of readmittance resulting from acute obstruction caused by pannus during 30 years of observation in patients with Medtronic-Hall aortic valve prostheses and to analyze the risk factors associated with pannus development. From 1982 to 2004, 1,187 patients in our department underwent aortic valve replacement with Medtronic-Hall mechanical monoleaflet valve prostheses. As of December 31, 2012, 27 of these patients (2.3%) had presented with acute valve dysfunction caused by pannus obstruction. The annual incidence of pannus was 0.7 per 1,000. The median time from the primary operation to prosthetic dysfunction was 11.1 years (range, 1.2 to 26.8 years). Of the 20 patients who underwent reoperation, 2 died. Seven patients died before reoperation. Women had a higher risk for the development of obstructing pannus, and patients with pannus obstruction were younger. Valve size was not an independent risk factor. Women and younger patients are at higher risk for pannus development. When acute dysfunction by pannus is suspected in a mechanical aortic valve, an immediate echocardiogram and an emergency aortic valve replacement should be carried out because of the potential of a fatal outcome. Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

The Melody® valve and Ensemble® delivery system for transcatheter pulmonary valve replacement

PubMed Central

McElhinney, Doff B; Hennesen, Jill T

2013-01-01

The Melody® transcatheter pulmonary valve (TPV) is a percutaneous valve system designed for the treatment of obstruction and/or regurgitation of prosthetic conduits placed between the right ventricle and pulmonary arteries in patients with congenital heart disease. In 2000, Melody TPV became the first transcatheter valve implanted in a human; in 2006 it became the first transcatheter valve commercially available anywhere in the world; and in 2010 it was launched as the first commercially available transcatheter valve in the United States. In this review, we present the clinical background against which the Melody valve was developed and implemented, introduce the rationale for and challenges of transcatheter valve technology for this population, outline the history and technical details of its development and use, and summarize currently available data concerning the performance of the device. PMID:23834411

Imbalance in Individual Researcher's Peer Review Activities Quantified for Four British Ecological Society Journals, 2003-2010

PubMed Central

Petchey, Owen L.; Fox, Jeremy W.; Haddon, Lindsay

2014-01-01

Researchers contribute to the scientific peer review system by providing reviews, and “withdraw” from it by submitting manuscripts that are subsequently reviewed. So far as we are aware, there has been no quantification of the balance of individual's contributions and withdrawals. We compared the number of reviews provided by individual researchers (i.e., their contribution) to the number required by their submissions (i.e. their withdrawals) in a large and anonymised database provided by the British Ecological Society. The database covered the Journal of Ecology, Journal of Animal Ecology, Journal of Applied Ecology, and Functional Ecology from 2003–2010. The majority of researchers (64%) did not have balanced contributions and withdrawals. Depending on assumptions, 12% to 44% contributed more than twice as much as required; 20% to 52% contributed less than half as much as required. Balance, or lack thereof, varied little in relation to the number of years a researcher had been active (reviewing or submitting). Researchers who contributed less than required did not lack the opportunity to review. Researchers who submitted more were more likely to accept invitations to review. These finding suggest overall that peer review of the four analysed journals is not in crisis, but only due to the favourable balance of over- and under-contributing researchers. These findings are limited to the four journals analysed, and therefore cannot include researcher's other peer review activities, which if included might change the proportions reported. Relatively low effort was required to assemble, check, and analyse the data. Broader analyses of individual researcher's peer review activities would contribute to greater quality, efficiency, and fairness in the peer review system. PMID:24658631

Imbalance in individual researcher's peer review activities quantified for four British Ecological Society journals, 2003-2010.

PubMed

Petchey, Owen L; Fox, Jeremy W; Haddon, Lindsay

2014-01-01

Researchers contribute to the scientific peer review system by providing reviews, and "withdraw" from it by submitting manuscripts that are subsequently reviewed. So far as we are aware, there has been no quantification of the balance of individual's contributions and withdrawals. We compared the number of reviews provided by individual researchers (i.e., their contribution) to the number required by their submissions (i.e. their withdrawals) in a large and anonymised database provided by the British Ecological Society. The database covered the Journal of Ecology, Journal of Animal Ecology, Journal of Applied Ecology, and Functional Ecology from 2003-2010. The majority of researchers (64%) did not have balanced contributions and withdrawals. Depending on assumptions, 12% to 44% contributed more than twice as much as required; 20% to 52% contributed less than half as much as required. Balance, or lack thereof, varied little in relation to the number of years a researcher had been active (reviewing or submitting). Researchers who contributed less than required did not lack the opportunity to review. Researchers who submitted more were more likely to accept invitations to review. These finding suggest overall that peer review of the four analysed journals is not in crisis, but only due to the favourable balance of over- and under-contributing researchers. These findings are limited to the four journals analysed, and therefore cannot include researcher's other peer review activities, which if included might change the proportions reported. Relatively low effort was required to assemble, check, and analyse the data. Broader analyses of individual researcher's peer review activities would contribute to greater quality, efficiency, and fairness in the peer review system.

The British and curriculum development in West Africa: A historical discourse

NASA Astrophysics Data System (ADS)

Ofori-Attah, Kwabena Dei

2006-09-01

THE BRITISH AND CURRICULUM DEVELOPMENT IN WEST AFRICA: A HISTORICAL STUDY - Only recently have African nations begun to make their way towards establishing genuinely autonomous education systems incorporating elements of indigenous culture. The present study examines the historical development of curriculum in British West Africa in its links with the educational activities of the early Christian missionaries and the imposition of British colonial rule. For over 300 years, the curriculum content was essentially European in nature. African interests and cultural practices were largely excluded, as "bookwork" was favored over "handwork". The colonial curriculum also helped introduce a new social order to West Africa, leading to the rise of new local elites reading, writing, and speaking foreign European languages. This study explores how the idea of a "civilized" person, promoted through the colonial school curriculum, developed new local elites with different sets of values and expectations that often made them strangers in their own societies. It also describes the connection between this curriculum and the repeated failure of education-reform efforts.

Comparison of acute elastic recoil between the SAPIEN-XT and SAPIEN valves in transfemoral-transcatheter aortic valve replacement.

PubMed

Garg, Aatish; Parashar, Akhil; Agarwal, Shikhar; Aksoy, Olcay; Hammadah, Muhammad; Poddar, Kanhaiya Lal; Puri, Rishi; Svensson, Lars G; Krishnaswamy, Amar; Tuzcu, E Murat; Kapadia, Samir R

2015-02-15

The SAPIEN-XT is a newer generation balloon-expandable valve created of cobalt chromium frame, as opposed to the stainless steel frame used in the older generation SAPIEN valve. We sought to determine if there was difference in acute recoil between the two valves. All patients who underwent transfemoral-transcatheter aortic valve replacement using the SAPIEN-XT valve at the Cleveland Clinic were included. Recoil was measured using biplane cine-angiographic image analysis of valve deployment. Acute recoil was defined as [(valve diameter at maximal balloon inflation) - (valve diameter after deflation)]/valve diameter at maximal balloon inflation (reported as percentage). Patients undergoing SAPIEN valve implantation were used as the comparison group. Among the 23 mm valves, the mean (standard deviation-SD) acute recoil was 2.77% (1.14) for the SAPIEN valve as compared to 3.75% (1.52) for the SAPIEN XT valve (P = 0.04). Among the 26 mm valves, the mean (SD) acute recoil was 2.85% (1.4) for the SAPIEN valve as compared to 4.32% (1.63) for the SAPIEN XT valve (P = 0.01). Multivariable linear regression analysis demonstrated significantly greater adjusted recoil in the SAPIEN XT valves as compared to the SAPIEN valves by 1.43% [(95% CI: 0.69-2.17), P < 0.001]. However, the residual peak gradient was less for SAPIEN XT compared to SAPIEN valves [18.86 mm Hg versus 23.53 mm Hg (P = 0.01)]. Additionally, no difference in paravalvular leak was noted between the two valve types (P = 0.78). The SAPIEN XT valves had significantly greater acute recoil after deployment compared to the SAPIEN valves. Implications of this difference in acute recoil on valve performance need to be investigated in future studies. © 2014 Wiley Periodicals, Inc.

Standardized endpoint definitions for transcatheter aortic valve implantation clinical trials: a consensus report from the Valve Academic Research Consortium†

PubMed Central

Leon, Martin B.; Piazza, Nicolo; Nikolsky, Eugenia; Blackstone, Eugene H.; Cutlip, Donald E.; Kappetein, Arie Pieter; Krucoff, Mitchell W.; Mack, Michael; Mehran, Roxana; Miller, Craig; Morel, Marie-angèle; Petersen, John; Popma, Jeffrey J.; Takkenberg, Johanna J.M.; Vahanian, Alec; van Es, Gerrit-Anne; Vranckx, Pascal; Webb, John G.; Windecker, Stephan; Serruys, Patrick W.

2011-01-01

Objectives To propose standardized consensus definitions for important clinical endpoints in transcatheter aortic valve implantation (TAVI), investigations in an effort to improve the quality of clinical research and to enable meaningful comparisons between clinical trials. To make these consensus definitions accessible to all stakeholders in TAVI clinical research through a peer reviewed publication, on behalf of the public health. Background Transcatheter aortic valve implantation may provide a worthwhile less invasive treatment in many patients with severe aortic stenosis and since its introduction to the medical community in 2002, there has been an explosive growth in procedures. The integration of TAVI into daily clinical practice should be guided by academic activities, which requires a harmonized and structured process for data collection, interpretation, and reporting during well-conducted clinical trials. Methods and results The Valve Academic Research Consortium established an independent collaboration between Academic Research organizations and specialty societies (cardiology and cardiac surgery) in the USA and Europe. Two meetings, in San Francisco, California (September 2009) and in Amsterdam, the Netherlands (December 2009), including key physician experts, and representatives from the US Food and Drug Administration (FDA) and device manufacturers, were focused on creating consistent endpoint definitions and consensus recommendations for implementation in TAVI clinical research programs. Important considerations in developing endpoint definitions included (i) respect for the historical legacy of surgical valve guidelines; (ii) identification of pathophysiological mechanisms associated with clinical events; (iii) emphasis on clinical relevance. Consensus criteria were developed for the following endpoints: mortality, myocardial infarction, stroke, bleeding, acute kidney injury, vascular complications, and prosthetic valve performance. Composite

Technical pitfalls and tips for the valve-in-valve procedure

PubMed Central

2017-01-01

Transcatheter aortic valve implantation (TAVI) has emerged as a viable treatment modality for patients with severe aortic valve stenosis and multiple co-morbidities. More recent indications include the use of transcatheter heart valves (THV) to treat degenerated bioprosthetic surgical heart valves (SHV), which are failing due to stenosis or regurgitation. Valve-in-valve (VIV) procedures in the aortic position have been performed with a variety of THV devices, although the balloon-expandable SAPIEN valve platform (Edwards Lifesciences Ltd, Irvine, CA, USA) and self-expandable CoreValve platform (Medtronic Inc., MN, USA) have been used in majority of the patients. VIV treatment is appealing as it is less invasive than conventional surgery but optimal patient selection is vital to avoid complications such as malposition, residual high gradients and coronary obstruction. To minimize the risk of complications, thorough procedural planning is critical. The first step is identification of the degenerated SHV, including its model, size, fluoroscopic appearance. Although label size and stent internal diameter (ID) are provided by the manufacturer, it is important to note the true ID. The true ID is the ID of a SHV after the leaflets are mounted and helps determine the optimal size of THV. The second step is to determine the type and size of the THV. Although this is determined in the majority of the cases by user preference, in certain situations one THV may be more suitable than another. As the procedure is performed under fluoroscopy, the third step is to become familiarized with the fluoroscopic appearance of both the SHV and THV. This helps to determine the landmarks for optimal positioning, which in turn determines the gradients and fixation. The fourth step is to assess the risk of coronary obstruction. This is performed with either aortic root angiography or ECG-gated computerised tomography (CT). Finally, the route of approach must be carefully planned. Once these

Valve stem and packing assembly

DOEpatents

Wordin, John J.

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.

Valve stem and packing assembly

DOEpatents

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.

Self-Rupturing Hermetic Valve

NASA Technical Reports Server (NTRS)

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

The early and midterm function of decellularized aortic valve allografts.

PubMed

da Costa, Francisco D A; Costa, Ana Claudia B A; Prestes, Roberta; Domanski, Ana Carolina; Balbi, Eduardo Mendel; Ferreira, Andreia D A; Lopes, Sergio Veiga

2010-12-01

This study evaluates the early and midterm results of decellularized aortic valve allografts (DAVA) as an aortic valve replacement. Between October 2005 and February 2010, 41 patients, 28 of whom were male, with a median age of 34 years (range, 0.1 to 71), had aortic valve replacement with DAVA. Decellularization was obtained with a 0.1% sodium dodecyl sulfate solution. Postoperative evaluation was performed with serial echocardiograms, magnetic resonance imaging, and multislice computed tomography studies to evaluate valve hemodynamics, allograft conduit dimensions, and calcification scores. There were 3 early deaths and 1 late death, with a mean follow-up of 19 months (range, 1 to 53). There was 1 reoperation due to a failed mitral valve repair. By echocardiography in all patients, the median immediate postoperative peak gradient was 7 mm Hg (range, 1 to 26 mm Hg), and at last follow-up it was 4 mm Hg (range, 1 to 16 mm Hg); valvular regurgitation was graded as none or trivial in all but 1 patient, who had a regurgitation graded as mild to moderate. By magnetic resonance imaging (n = 4), mean root dimensions were stable at the annulus (24 mm), sinus of Valsalva (33 mm), and sinotubular junction (28 mm). By computed tomography (n = 22), there was only discrete conduit calcification (median calcium score 63 Hounsfield units [HU]; range, 0 to 894 HU) to 3 years of follow-up. Conduit biopsy in the patient who underwent reoperation demonstrated well-preserved wall structure, absence of calcification, and limited in vivo host repopulation. The early and midterm results with DAVA demonstrated stable structural integrity, low rate of calcification, and adequate hemodynamics. Although longer periods of observation are necessary, DAVA appears to be a promising alternative for aortic valve replacement in selected patients. Copyright © 2010 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Cardiovascular disease mortality in British merchant shipping and among British seafarers ashore in Britain.

PubMed

Roberts, Stephen E; Jaremin, Bogdan

2010-01-01

The objective was to investigate trends in work-related mortality from cardiovascular disease (CVD) among seafarers employed in British merchant shipping from 1919 to 2005, to compare CVD mortality among British seafarers at work in British shipping - and ashore in Britain - with that in the general British population, and to investigate work-related CVD mortality in British shipping during recent years according to factors such as rank, nationality, location, and type of ship. A longitudinal study based on examination of death inquiry files and death registers, official death returns, and information from occupational mortality decennial supplements. The main outcome measures were population-based mortality rates and standardised mortality ratios. There was an increase in work-related CVD mortality throughout much of the period from 1919 to 1962, but a subsequent reduction to 2005. Work-related mortality from CVD and ischaemic heart disease (IHD) was lower among seafarers employed in British shipping than in the corresponding general population (SMRs = 0.35 to 0.46), but mortality from CVD among British seafarers ashore in Britain was often increased. An elevated risk of work-related CVD mortality was also identified among the crews of North Sea offshore ships. This study shows a healthy worker effect against CVD mortality among seafarers at work in British shipping, but increased risks among British seafarers ashore in Britain, which would include seafarers discharged through CVD morbidity and other illnesses. The high risks of CVD mortality among seafarers in North Sea supply ships may reflect particular work-related hazards in this sector.

A survey of the role of the UK physicist in nuclear medicine: a report of a joint working group of the British Institute of Radiology, British Nuclear Medicine Society, and the Institute of Physics and Engineering in Medicine.

PubMed

Tindale, W B; Thorley, P J; Nunan, T O; Lewington, V; Shields, R A; Williams, N R

2003-01-01

Guidelines for the provision of physics support to nuclear medicine were published in 1999 by a joint working group of the British Institute of Radiology, the British Nuclear Medicine Society, and the Institute of Physics and Engineering in Medicine. Following publication of the guidelines, a survey was conducted by the working group to gather data on the actual level of physicist support in UK hospitals of different types and on the activities undertaken by physicists. The data were collected in the 12 months following the publication of guidelines and cover different hospital models and seven UK regions. The results provide evidence that many of the smaller units - small teaching hospitals and, particularly, small district general hospitals - have insufficient physics support. Although, on average, there is good agreement between the guidelines and the survey data for medium and large district general hospitals, there is wide variation in the level of physics provision between hospitals delivering apparently similar services. This emphasizes the need for national guidelines, against which institutions may be bench-marked and which may be used as a recommendation for the staffing levels necessary to ensure services are delivered safely and standards are not compromised. The complexity and variety of workload is an important factor in determining the level of physics support. As services develop, it is vital that this aspect is recognized to ensure that appropriate resources are available for the required physics input, even if any new service represents only a modest clinical throughput in terms of patient numbers.

Cryogenic Cam Butterfly Valve

NASA Technical Reports Server (NTRS)

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.

Validation of the Tensoval Duo Control II blood pressure monitor for clinic use and self-measurement according to the British Hypertension Society protocol and the European Society of Hypertension International Protocol Revision 2010.

PubMed

de Greeff, Annemarie; Shennan, Andrew H

2013-06-01

The Tensoval Duo Control II is an automated upper arm device that uses a combination of oscillometric and auscultatory technology to determine blood pressure noninvasively. The accuracy of this device was assessed according to the British Hypertension Society (BHS) protocol and the European Society of Hypertension International Protocol revision 2010 (ESH-IP2) in an adult population. Ethical approval was obtained. Eighty-five and 33 adult individuals, respectively, were recruited to fulfil the requirements of each protocol. Trained observers took nine sequential same-arm measurements alternating between a mercury sphygmomanometer and the device. The device had to achieve at least a B grade for both systolic and diastolic pressures to pass the BHS protocol and had to fulfil the criteria of all three phases of the ESH-IP2 protocol to receive recommendation. The device achieved an A/A grading for the BHS protocol and passed all three phases of the ESH-IP2 protocol. The mean difference±SD for the BHS/ESH protocols, respectively, was -1.8±6.5/-0.7±5.7 mmHg for systolic pressure and 1.9±5.1/2.4±4.5 mmHg for diastolic pressure. The device maintained its A/A grading throughout the low-pressure, medium-pressure and high-pressure ranges. The Tensoval Duo Control II device is recommended for clinical and home use according to both the BHS and the ESH-IP2 standard.

Slide valve apparatus for internal combustion engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, B.A.; McMahan, T.O.

This patent describes an internal combustion engine including a combustion cylinder having an opening at one end thereof, a piston mounted within the cylinder for coaxial reciprocable movement, a driven crankshaft, and a connecting rod connecting the crankshaft to the cylinder for linear reciprocable movement of the piston in response to the rotary movement of the crankshaft, a valve apparatus comprising: (a) a valve chamber extending longitudinally across and in fluid communication with the opening in the cylinder, (b) an intake valve plate having a longitudinal axis mounted within the valve chamber for slidable, reciprocable, longitudinal movement, (c) an exhaustmore » valve plate having a longitudinal axis mounted within the valve chamber alongside the intake valve plate for slidable, reciprocable, longitudinal movement and parallel to the longitudinal axis of the intake valve plate, (d) each of the valve plates having a plurality of longitudinally spaced valve ports therein, the valve ports comprising movable intake valve ports in the intake valve plate and movable exhaust valve ports in the exhaust valve plate, (e) the valve chamber comprising a planar wall on the opposite side of the valve plates from the cylinder opening and having a plurality of fixed valve ports therethrough. The fixed valve ports being equal in number and substantially equal in size and spacing as the movable intake and exhaust valve ports, whereby the movable intake valve ports are adapted to register with their corresponding fixed valve ports when the intake valve plate is in its intake operative position for opening fluid communication between the cylinder and the corresponding fixed valve ports.« less

Three-dimensional printed trileaflet valve conduits using biological hydrogels and human valve interstitial cells.

PubMed

Duan, B; Kapetanovic, E; Hockaday, L A; Butcher, J T

2014-05-01

Tissue engineering has great potential to provide a functional de novo living valve replacement, capable of integration with host tissue and growth. Among various valve conduit fabrication techniques, three-dimensional (3-D) bioprinting enables deposition of cells and hydrogels into 3-D constructs with anatomical geometry and heterogeneous mechanical properties. Successful translation of this approach, however, is constrained by the dearth of printable and biocompatible hydrogel materials. Furthermore, it is not known how human valve cells respond to these printed environments. In this study, 3-D printable formulations of hybrid hydrogels are developed, based on methacrylated hyaluronic acid (Me-HA) and methacrylated gelatin (Me-Gel), and used to bioprint heart valve conduits containing encapsulated human aortic valvular interstitial cells (HAVIC). Increasing Me-Gel concentration resulted in lower stiffness and higher viscosity, facilitated cell spreading, and better maintained HAVIC fibroblastic phenotype. Bioprinting accuracy was dependent upon the relative concentrations of Me-Gel and Me-HA, but when optimized enabled the fabrication of a trileaflet valve shape accurate to the original design. HAVIC encapsulated within bioprinted heart valves maintained high viability, and remodeled the initial matrix by depositing collagen and glyosaminoglycans. These findings represent the first rational design of bioprinted trileaflet valve hydrogels that regulate encapsulated human VIC behavior. The use of anatomically accurate living valve scaffolds through bioprinting may accelerate understanding of physiological valve cell interactions and progress towards de novo living valve replacements. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Lock For Valve Stem

NASA Technical Reports Server (NTRS)

Burley, Richard K.; Guirguis, Kamal S.

1991-01-01

Simple, cheap device locks valve stem so its setting cannot be changed by unauthorized people. Device covers valve stem; cover locked in place with standard padlock. Valve lock made of PVC pipe and packing band. Shears, drill or punch, and forming rod only tools needed.

Design and development of a large diameter high pressure fast acting propulsion valve and valve actuator

NASA Technical Reports Server (NTRS)

Srinivasan, K. V.

1986-01-01

The design and development of a large diameter high pressure quick acting propulsion valve and valve actuator is described. The valve is the heart of a major test facility dedicated to conducting full scale performance tests of aircraft landing systems. The valve opens in less than 300 milliseconds releasing a 46-centimeter- (18-in.-) diameter water jet and closes in 300 milliseconds. The four main components of the valve, i.e., valve body, safety shutter, high speed shutter, and pneumatic-hydraulic actuator, are discussed. This valve is unique and may have other aerospace and industrial applications.

Design and Development of a Large Diameter, High Pressure, Fast Acting Propulsion Valve and Valve Actuator

NASA Technical Reports Server (NTRS)

Srinivasan, K. V.

1986-01-01

This paper describes the design and development of a large diameter high pressure quick acting propulsion valve and valve actuator. The valve is the heart of a major test facility dedicated to conducting full scale performance tests of aircraft landing gear systems. The valve opens in less than 300 milliseconds releasing a 46 cm (18 in) diameter water jet and closes in 300 milliseconds. The four main components of the valve, i.e., valve body, safety shutter, high speed shutter, and pneumatic-hydraulic actuator, are discussed. This valve is unique and may have other aerospace and industrial applications.

Björk-Shiley convexoconcave valves: susceptibility artifacts at brain MR imaging and mechanical valve fractures.

PubMed

van Gorp, Maarten J; van der Graaf, Yolanda; de Mol, Bas A J M; Bakker, Chris J G; Witkamp, Theo D; Ramos, Lino M P; Mali, Willem P T M

2004-03-01

To assess the relationship between heart valve history and susceptibility artifacts at magnetic resonance (MR) imaging of the brain in patients with Björk-Shiley convexoconcave (BSCC) valves. MR images of the brain were obtained in 58 patients with prosthetic heart valves: 20 patients had BSCC valve replacements, and 38 had other types of heart valves. Two experienced neuroradiologists determined the presence or absence of susceptibility artifacts in a consensus reading. Artifacts were defined as characteristic black spots that were visible on T2*-weighted gradient-echo MR images. The statuses of the 20 explanted BSCC valves-specifically, whether they were intact or had an outlet strut fracture (OSF) or a single-leg fracture (SLF)-had been determined earlier. Number of artifacts seen at brain MR imaging was correlated with explanted valve status, and differences were analyzed with nonparametric statistical tests. Significantly more patients with BSCC valves (17 [85%] of 20 patients) than patients with other types of prosthetic valves (18 [47%] of 38 patients) had susceptibility artifacts at MR imaging (P =.005). BSCC valve OSFs were associated with a significantly higher number of artifacts than were intact BSCC valves (P =.01). No significant relationship between SLF and number of artifacts was observed. Susceptibility artifacts at brain MR imaging are not restricted to patients with BSCC valves. These artifacts can be seen on images obtained in patients with various other types of fractured and intact prosthetic heart valves. Copyright RSNA, 2004

9. BUTTERFLY VALVE CONTROL DIABLO POWERHOUSE. BUTTERFLY VALVES WERE MANUFACTURED ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. BUTTERFLY VALVE CONTROL DIABLO POWERHOUSE. BUTTERFLY VALVES WERE MANUFACTURED BY THE PELTON WATER WHEEL COMPANY IN 1931, 1989. - Skagit Power Development, Diablo Powerhouse, On Skagit River, 6.1 miles upstream from Newhalem, Newhalem, Whatcom County, WA

Canadian Cardiovascular Society/Canadian Society of Cardiac Surgeons/Canadian Society for Vascular Surgery Joint Position Statement on Open and Endovascular Surgery for Thoracic Aortic Disease.

PubMed

Appoo, Jehangir J; Bozinovski, John; Chu, Michael W A; El-Hamamsy, Ismail; Forbes, Thomas L; Moon, Michael; Ouzounian, Maral; Peterson, Mark D; Tittley, Jacques; Boodhwani, Munir

2016-06-01

In 2014, the Canadian Cardiovascular Society (CCS) published a position statement on the management of thoracic aortic disease addressing size thresholds for surgery, imaging modalities, medical therapy, and genetics. It did not address issues related to surgical intervention. This joint Position Statement on behalf of the CCS, Canadian Society of Cardiac Surgeons, and the Canadian Society for Vascular Surgery provides recommendations about thoracic aortic disease interventions, including: aortic valve repair, perfusion strategies for arch repair, extended arch hybrid reconstruction for acute type A dissection, endovascular management of arch and descending aortic aneurysms, and type B dissection. The position statement is constructed using Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology, and has been approved by the primary panel, an international secondary panel, and the CCS Guidelines Committee. Advent of endovascular technology has improved aortic surgery safety and extended the indications of minimally invasive thoracic aortic surgery. The combination of safer open surgery with endovascular treatment has improved patient outcomes in this rapidly evolving subspecialty field of cardiovascular surgery. Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

Self-compensating solenoid valve

NASA Technical Reports Server (NTRS)

Woeller, Fritz H. (Inventor); Matsumoto, Yutaka (Inventor)

1987-01-01

A solenoid valve is described in which both an inlet and an outlet of the valve are sealed when the valve is closed. This double seal compensates for leakage at either the inlet or the outlet by making the other seal more effective in response to the leakage and allows the reversal of the flow direction by simply switching the inlet and outlet connections. The solenoid valve has a valve chamber within the valve body. Inlet and outlet tubes extend through a plate into the chamber. A movable core in the chamber extends into the solenoid coil. The distal end of the core has a silicone rubber plug. Other than when the solenoid is energized, the compressed spring biases the core downward so that the surface of the plug is in sealing engagement with the ends of the tubes. A leak at either end increases the pressure in the chamber, resulting in increased sealing force of the plug.

Concomitant Transapical Transcatheter Valve Implantations: Edwards Sapien Valve for Severe Mitral Regurgitation in a Patient with Failing Mitral Bioprostheses and JenaValve for the Treatment of Pure Aortic Regurgitation.

PubMed

Aydin, Unal; Gul, Mehmet; Aslan, Serkan; Akkaya, Emre; Yildirim, Aydin

2015-04-28

Transcatheter valve implantation is a novel interventional technique, which was developed as an  alternative therapy for surgical aortic valve replacement in inoperable patients with severe aortic stenosis. Despite limited experience in using transcatheter valve implantation for mitral and aortic regurgitation, transapical transcatheter aortic valve implantation and valve-in-valve implantation for degenerated mitral valve bioprosthesis can be performed in high-risk patients who are not candidates for conventional replacement surgery. In this case, we present the simultaneous transcatheter valve implantation via transapical approach for both degenerated bioprosthetic mitral valve with severe regurgitation and pure severe aortic regurgitation.

Bidirectional piston valve

DOEpatents

Fischer, Harry C.

1977-01-01

This invention is a reversing valve having an inlet, an outlet, and an inlet-outlet port. The valve is designed to respond to the introduction of relatively high-pressure fluid at its inlet or, alternatively, of lower-pressure fluid at its inlet-outlet port. The valve includes an axially slidable assembly which is spring-biased to a position where it isolates the inlet and connects the inlet-outlet port to the outlet. The admission of high-pressure fluid to the inlet displaces the slidable assembly to a position where the outlet is isolated and the inlet is connected to the inlet-outlet port. The valve is designed to minimize pressure drops and leakage. It is of a reliable and comparatively simple design.

Identifying British Army infantry recruit population characteristics using biographical data.

PubMed

Kiernan, M D; Arthur, A; Repper, J; Mukhuty, S; Fear, N T

2016-04-01

The infantry accounts for more than a quarter of the British Army but there is a lack of data about the social and educational background of its recruits. To provide an insight into British Army infantry recruits' personal, social and educational background prior to enlistment. The study sample consisted of infantry recruits who enlisted into the British Army School of Infantry. Each recruit completed a 95-item biographical questionnaire. Descriptive statistics were used to describe the sample in terms of demographic, physical, personal, social and educational attributes. The study sample consisted of 1000 male recruits. Over half of the recruits were consuming alcohol at a hazardous or harmful level prior to enlistment and 60% of recruits had used cannabis prior to joining the Army. Academic attainment was low, with the majority of recruits achieving GCSE grade C and below in most subjects, with 15% not taking any examinations. Over half the recruits had been in trouble with the police and either been suspended or expelled from school. Substance misuse and poor behaviour are highly prevalent among recruits prior to enlistment. Taken alongside existing evidence that some of these problems are commonplace among personnel in regular service, the assumption that the British Army infantry is, in itself, a cause of these behaviours should be questioned. © The Author 2015. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Anterior urethral valve associated with posterior urethral valves.

PubMed

Kajbafzadeh, A M; Jangouk, P; Ahmadi Yazdi, C

2005-12-01

The association of anterior urethral valve (AUV) with posterior urethral valve (PUV) is rare. A 7-month-old infant was presented at a district hospital with episodes of acute pyelonephritis. He was treated medically and a voiding cystourethrogram (VCUG) confirmed bilateral vesico-urethral reflux. The presence of concomitant AUV and PUV was not recognized. He underwent several surgical procedures, which failed. He had reflux recurrence following two antireflux procedures. He had urinary retention after each operation, which was managed by vesicostomy and perineal urethrostomy. At the age of 3.5 years, he was referred to our paediatric urology clinic. Noticing the AUV and PUV in the past VCUG, the valves were fulgurated. Urodynamic study before and 3 months after valve ablation showed a high voiding pressure. VCUG 6 months following ablation showed no reflux, but several uroflowmetric studies showed a staccato and interrupted pattern. Empirical treatment with an alpha-blocker was started. One year after treatment, a repeat VCUG showed no reflux. Uroflowmetry and urodynamic studies returned to normal. The perineal urethrostomy was closed. The child was asymptomatic after 9 months of follow up.

Transcatheter aortic valve implantation in patients with bicuspid aortic valve stenosis.

PubMed

Wijesinghe, Namal; Ye, Jian; Rodés-Cabau, Josep; Cheung, Anson; Velianou, James L; Natarajan, Madhu K; Dumont, Eric; Nietlispach, Fabian; Gurvitch, Ronen; Wood, David A; Tay, Edgar; Webb, John G

2010-11-01

We evaluated transcatheter aortic valve implantation (TAVI) in high-risk patients with bicuspid aortic valve (BAV) stenosis. TAVI shows promise in the treatment of severe stenosis of triscupid aortic valves, especially in high-risk patients. However, BAV stenosis has been considered a contraindication to TAVI. Eleven patients (age 52 to 90 years) with symptomatic severe BAV stenosis underwent TAVI at 3 Canadian tertiary hospitals between May 2006 and April 2010. All patients were considered high risk for surgical aortic valve replacement. Edwards-SAPIEN transcatheter heart valves (Edwards Lifesciences, Inc., Irvine, California) were used. Transfemoral or transapical access was selected, depending on the adequacy of femoral access. Access was transfemoral in 7 patients and transapical in 4 patients. There were no intraprocedural complications. Significant symptomatic and hemodynamic improvement was observed in 10 of 11 patients. Baseline aortic valve area of 0.65 ± 0.17 cm(2) and mean transaortic pressure gradient of 41 ± 22.4 mm Hg were improved to 1.45 ± 0.3 cm(2) and 13.4 ± 5.7 mm Hg, respectively. Two patients had moderate perivalvular leaks. At the 30-day follow-up there were 2 deaths due to multisystem failure in 2 transapical patients. In 1 patient an undersized, suboptimally positioned, unstable valve required late conversion to open surgery. TAVI in selected high-risk patients with severe BAV stenosis can be successfully performed with acceptable clinical outcomes but will require further evaluation. Copyright © 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Systolic Anterior Motion of the Mitral Valve after Mitral Valve Repair

PubMed Central

Sternik, Leonid; Zehr, Kenton J.

2005-01-01

Factors predisposing patients to systolic anterior motion of the mitral valve (SAM) with left ventricular outflow tract (LVOT) obstruction after mitral valve repair are the presence of a myxomatous mitral valve with redundant leaflets, a nondilated hyperdynamic left ventricle, and a short distance between the mitral valve coaptation point and the ventricular septum after repair. From December 1999 through March 2000, we used our surgical method in 6 patients with severely myxomatous regurgitant mitral valves who were at risk of developing SAM. Leaflets were markedly redundant in all 6. Left ventricular function was hyperdynamic in 4 patients and normal in 2. Triangular or quadrangular resection of the midportion of the posterior leaflet and posterior band annuloplasty were performed. To prevent SAM and LVOT obstruction, extra, posteriorly directed, mid-posterior-leaflet secondary chordae tendineae, which would otherwise have been resected, were transferred to the underside of the middle of the mid-anterior leaflet with a small piece of associated valve as an anchoring pledget. This kept the redundant anterior leaflet edge, which extended below the coaptation point, away from the LVOT. No post-repair SAM or LVOT obstruction was observed on intraoperative or discharge echocardiography. All patients had no or trivial residual mitral regurgitation. We conclude that extra chordae tendineae, when available, can be used in mitral valve repair to tether the redundant anterior leaflet and thus prevent it from flipping into the LVOT. This will theoretically prevent SAM and LVOT obstruction in patients with risk factors for SAM. PMID:15902821

Fast closing valve

DOEpatents

Hanson, Clark L.

1984-01-10

A valve is provided for protecting the high vacuum of a particle accelera in the event of air leakage, wherein the valve provides an axially symmetrical passage to avoid disturbance of the partical beam during normal operation, and yet enables very rapid and tight closure of the beam-carrying pipe in the event of air leakage. The valve includes a ball member (30) which can rotate between a first position wherein a bore (32) in the member is aligned with the beam pipe, and a second position out of line with the pipe. A seal member (38) is flexibly sealed to the pipe, and has a seal end which can move tightly against the ball member after the bore has rotated out of line with the pipe, to thereby assure that the seal member does not retard rapid rotation of the ball valve member. The ball valve member can be rapidly rotated by a conductive arm (40) fixed to it and which is rotated by the discharge of a capacitor bank through coils (44, 45) located adjacent to the arm.

Downhole surge valve for earth boring apparatus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, D.W.

1990-05-29

This patent describes a boring tool assembly having an underground percussion mole boring tool powered by a working fluid, the tool being driven through the earth by a rigid drill string pushed by a drilling frame, and a downhole valve assembly fixed between the downhole end of the drill string and the too, the improved downhole valve assembly. It comprises: a valve spool having an open first end, a closed second end and a peripheral sidewall, an axial bore extending partly through the valve spool from the open first end; a radial passage adjacent the closed second and of themore » valve spool, the radial passage extending radially from the valve spool axial bore through the valve spool peripheral sidewall; an axial groove in the peripheral sidewall of the valve spool; a valve body having a first end, a second end and a peripheral sidewall, an axial bore extending through the valve body, the valve spool extending through the valve body axial bore so that the second end of the valve body is adjacent the closed second end of the valve spool, the valve spool being axially moveable within the valve body axial bore; an axial slot; a free-floating key element; a valve housing; and seal means.« less

Update of transcatheter valve treatment

PubMed Central

Liu, Xian-bao; Wang, Jian-an

2013-01-01

Transcatheter valve implantation or repair has been a very promising approach for the treatment of valvular heart diseases since transcatheter aortic valve implantation (TAVI) was successfully performed in 2002. Great achievements have been made in this field (especially TAVI and transcatheter mitral valve repair—MitraClip system) in recent years. Evidence from clinical trials or registry studies has proved that transcatheter valve treatment for valvular heart diseases is safe and effective in surgical high-risk or inoperable patients. As the evidence accumulates, transcatheter valve treatment might be an alterative surgery for younger patients with surgically low or intermediate risk valvular heart diseases in the near future. In this paper, the updates on transcatheter valve treatment are reviewed. PMID:23897785

Pressure control valve. [inflating flexible bladders

NASA Technical Reports Server (NTRS)

Lambson, K. H. (Inventor)

1980-01-01

A control valve is provided which is adapted to be connected between a pressure source, such as a vacuum pump, and a pressure vessel so as to control the pressure in the vessel. The valve comprises a housing having a longitudinal bore which is connected between the pump and vessel, and a transversely movable valve body which controls the air flow through an air inlet in the housing. The valve body includes cylindrical and conical shaped portions which cooperate with reciprocally shaped portions of the housing to provide flow control. A filter in the air inlet removes foreign matter from the air. The bottom end of the valve body is screwed into the valve housing control knob formed integrally with the valve body and controls translation of the valve body, and the opening and closing of the valve.

Valve-sparing aortic root replacement in Loeys-Dietz syndrome.

PubMed

Patel, Nishant D; Arnaoutakis, George J; George, Timothy J; Allen, Jeremiah G; Alejo, Diane E; Dietz, Harry C; Cameron, Duke E; Vricella, Luca A

2011-08-01

Loeys-Dietz syndrome (LDS) is a recently recognized aggressive aortic disorder characterized by root aneurysm, arterial tortuosity, hypertelorism, and bifid uvula or cleft palate. The results of prophylactic root replacement using valve-sparing procedures (valve-sparing root replacement [VSRR]) in patients with LDS is not known. We reviewed all patients with clinical and genetic (transforming growth factor-β receptor mutations) evidence of LDS who underwent VSRR at our institution. Echocardiographic and clinical data were obtained from hospital and follow-up clinic records. From 2002 to 2009, 31 patients with a firm diagnosis of LDS underwent VSRR for aortic root aneurysm. Mean age was 15 years, and 24 (77%) were children. One (3%) patient had a bicuspid aortic valve. Preoperative sinus diameter was 3.9±0.8 cm (z score 7.0±2.9) and 2 (6%) had greater than 2+ aortic insufficiency. Thirty patients (97%) underwent reimplantation procedures using a Valsalva graft. There were no operative deaths. Mean follow-up was 3.6 years (range, 0 to 7 years). One patient required late repair of a pseudoaneurysm at the distal aortic anastomosis, and 1 had a conversion to a David reimplantation procedure after a Florida sleeve operation. No patient suffered thromboembolism or endocarditis, and 1 (3%) patient experienced greater than 2+ late aortic insufficiency. No patient required late aortic valve repair or replacement. Loeys-Dietz syndrome is an aggressive aortic aneurysm syndrome that can be addressed by prophylactic aortic root replacement with low operative risk. Valve-sparing procedures have encouraging early and midterm results, similar to those in Marfan syndrome, and are an attractive option for young patients. Copyright © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Regional survey of tuberculosis risk assessment in rheumatology outpatients commencing anti-TNF-alpha treatment in relation to British Thoracic Society guidelines.

PubMed

John, H; Buckley, C; Koh, L; Obrenovic, K; Erb, N; Rowe, I F

2009-06-01

The aim of this study was to analyse tuberculosis (TB) risk assessment for rheumatology patients commencing anti-tumour necrosis factor-alpha (anti-TNF-alpha) therapy using the British Thoracic Society (BTS) guidelines. Data were obtained retrospectively on 856 outpatients regionally receiving anti-TNF-alpha. Prior to commencing treatment, patients had the following assessments documented: respiratory examination, 47.4%; chest X-ray, 84.5%; TB history, 92.9%; and advice about TB risk, 45.8%. Of the 856 patients, 94.3% were on immunosuppressives but 27% had a tuberculin test; 12.6% had > or =1 high-risk factors for TB. In total, 3.4% were referred to a TB specialist and of these, 24.1% had no risk factors for TB. Of patients with > or =1 risk factor, 76.9% were not referred. Only 4/28 patients at high risk for TB due to ethnicity or birthplace received chemoprophylaxis. Marked inter-unit variation was demonstrated and it was evident that patients require improved screening for TB. Greater awareness is necessary of patients with risk factors, particularly ethnicity, to facilitate more appropriate targeting of chemoprophylaxis. Multi-centre audit is a valuable clinical governance tool.

"Bail out" procedures for malpositioning of aortic valve prosthesis (CoreValve).

PubMed

Vavouranakis, Manolis; Vrachatis, Dimitrios A; Toutouzas, Konstantinos P; Chrysohoou, Christina; Stefanadis, Christodoulos

2010-11-05

Two techniques for correcting malpositioning occurring during percutaneous aortic valve replacement (PAVR) with the CoreValve ReValving™ System are described in this article. The "Removing and Reinserting Technique" was used in 2 patients, in whom the prosthesis was positioned too high. The "Snare Technique" was used in 1 patient, in whom the prosthesis was implanted too low. In all patients the aortic valve prosthesis was successfully re-implanted. Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.

Passively actuated valve

DOEpatents

Modro, S. Michael; Ougouag, Abderrafi M.

2005-09-20

A passively actuated valve for isolating a high pressure zone from a low pressure zone and discontinuing the isolation when the pressure in the high pressure zone drops below a preset threshold. If the pressure in the high pressure zone drops below the preset threshold, the valve opens and allows flow from the high pressure zone to the low pressure zone. The valve remains open allowing pressure equalization and back-flow should a pressure inversion between the two pressure zone occur.

Mitral Valve Prolapse

MedlinePlus

... valve syndrome . What happens during MVP? Watch an animation of mitral valve prolapse When the heart pumps ( ... our brochures Popular Articles 1 Understanding Blood Pressure Readings 2 Sodium and Salt 3 Heart Attack Symptoms ...

Heart valve surgery

MedlinePlus

... with an artificial valve (this is called the Ross Procedure). This procedure may be useful for people ... valve that does not close all the way will allow blood to leak backwards. This is called ...

Intraluminal valves: development, function and disease

PubMed Central

Geng, Xin; Cha, Boksik; Mahamud, Md. Riaj

2017-01-01

ABSTRACT The circulatory system consists of the heart, blood vessels and lymphatic vessels, which function in parallel to provide nutrients and remove waste from the body. Vascular function depends on valves, which regulate unidirectional fluid flow against gravitational and pressure gradients. Severe valve disorders can cause mortality and some are associated with severe morbidity. Although cardiac valve defects can be treated by valve replacement surgery, no treatment is currently available for valve disorders of the veins and lymphatics. Thus, a better understanding of valves, their development and the progression of valve disease is warranted. In the past decade, molecules that are important for vascular function in humans have been identified, with mouse studies also providing new insights into valve formation and function. Intriguing similarities have recently emerged between the different types of valves concerning their molecular identity, architecture and development. Shear stress generated by fluid flow has also been shown to regulate endothelial cell identity in valves. Here, we review our current understanding of valve development with an emphasis on its mechanobiology and significance to human health, and highlight unanswered questions and translational opportunities. PMID:29125824

Anterior urethral valves without diverticulae: a report of two cases and a review of the literature.

PubMed

Singh, Dig Vijay; Taneja, Rajesh

2014-05-01

Two unusual cases of anterior urethral valves (AUV) without diverticulae are presented. The first case is a male child born with prenatal diagnosis of bilateral hydronephrosis. On cystoscopy, iris-like diaphragm valves were encountered about 3 mm distal to the skeletal sphincter. In the second case, an 18-month-old male child was investigated for recurrent febrile urinary tract infections and obstructed urinary symptoms. Cystoscopy confirmed the presence of slit-like valves 5 mm distal to the skeletal sphincter. Fulguration of the AUVs was performed in both cases. It may be worthwhile to review all cases of anterior urethral obstruction collectively and re-categorize them appropriately to include the unusual AUVs without diverticulum in that classification. © 2013 Japanese Teratology Society.

Variable Valve Actuation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeffrey Gutterman; A. J. Lasley

2008-08-31

Many approaches exist to enable advanced mode, low temperature combustion systems for diesel engines - such as premixed charge compression ignition (PCCI), Homogeneous Charge Compression Ignition (HCCI) or other HCCI-like combustion modes. The fuel properties and the quantity, distribution and temperature profile of air, fuel and residual fraction in the cylinder can have a marked effect on the heat release rate and combustion phasing. Figure 1 shows that a systems approach is required for HCCI-like combustion. While the exact requirements remain unclear (and will vary depending on fuel, engine size and application), some form of substantially variable valve actuation ismore » a likely element in such a system. Variable valve actuation, for both intake and exhaust valve events, is a potent tool for controlling the parameters that are critical to HCCI-like combustion and expanding its operational range. Additionally, VVA can be used to optimize the combustion process as well as exhaust temperatures and impact the after treatment system requirements and its associated cost. Delphi Corporation has major manufacturing and product development and applied R&D expertise in the valve train area. Historical R&D experience includes the development of fully variable electro-hydraulic valve train on research engines as well as several generations of mechanical VVA for gasoline systems. This experience has enabled us to evaluate various implementations and determine the strengths and weaknesses of each. While a fully variable electro-hydraulic valve train system might be the 'ideal' solution technically for maximum flexibility in the timing and control of the valve events, its complexity, associated costs, and high power consumption make its implementation on low cost high volume applications unlikely. Conversely, a simple mechanical system might be a low cost solution but not deliver the flexibility required for HCCI operation. After modeling more than 200 variations of the

Space Vehicle Valve System

NASA Technical Reports Server (NTRS)

Kelley, Anthony R. (Inventor); Lindner, Jeffrey L. (Inventor)

2014-01-01

The present invention is a space vehicle valve system which controls the internal pressure of a space vehicle and the flow rate of purged gases at a given internal pressure and aperture site. A plurality of quasi-unique variable dimension peaked valve structures cover the purge apertures on a space vehicle. Interchangeable sheet guards configured to cover valve apertures on the peaked valve structure contain a pressure-activated surface on the inner surface. Sheet guards move outwardly from the peaked valve structure when in structural contact with a purge gas stream flowing through the apertures on the space vehicle. Changing the properties of the sheet guards changes the response of the sheet guards at a given internal pressure, providing control of the flow rate at a given aperture site.

ULTRA HIGH VACUUM VALVE

DOEpatents

Fry, W.A.

1962-05-29

A valve for high vacuum applications such as the CStellarator where chamber pressures as low as 2 x 10/sup -10/ mm Hg are necessary is designed with a line-of-sight path through the valve for visual inspection of the contents of reactants in such chambers. The valve comprises a turnable resilient metal ball having an aperture therethrough, means for selectively turning the ball to rotate the axis of its line-of-sight path, and soft, deformable opposing orifices that are movable relatively toward said ball to seal with opposite ball surfaces upon said movement of said axis of said line-of-sight path. The valve also includes a bellows seal connected between said orifices and internal actuating means that eliminates the requirement for gasketed turnable valve closing stems. (AEC)

Does the disparity in baseline characteristics of patients undergoing transcatheter aortic valve replacement with 23 mm vs. 26 mm valves impact clinical outcome?

PubMed

Escárcega, Ricardo O; Magalhaes, Marco A; Baker, Nevin C; Lipinski, Michael J; Minha, Sa'ar; Torguson, Rebecca; Chen, Fang; Satler, Lowell F; Pichard, Augusto D; Waksman, Ron

2016-01-01

We sought to identify if baseline characteristic differences in patients who receive a 23 mm vs. 26 mm valve impact clinical outcomes. Transcatheter aortic valve replacement (TAVR) is currently an approved therapy for patients with severe aortic stenosis who are considered inoperable or are at high risk. We retrospectively examined baseline characteristics and outcomes of patients receiving a 23 mm (n = 132) vs. 26 mm valve (n = 81) via the transfemoral approach. Gender (P < 0.01), previous coronary artery bypass surgery (P < 0.01), history of atrial fibrillation (P = 0.04), and mean Society of Thoracic Surgeons (STS) score (P < 0.01) were significantly different between groups. There were no significant differences in the rates of minor/major vascular complications (2.2 vs. 3.7%, P = 0.68 and 13.0 vs. 12.3%, P = 0.89, respectively). Bleeding complications were also comparable (major bleed 2.3 vs. 1%, P >0.99, minor bleed 19.0 vs. 22.0%, P = 0.67 and life threatening bleed 7.0 vs. 5.0%, P = 0.77). In-hospital death (6.0 vs. 5.0%, P >0.99), 30-day all-cause death (7.6 vs. 6.2%, P = 0.69), and all-cause death at 1 year (17.4 vs. 25.9%, P = 0.13) were also similar between groups. Gender, valve size, previous coronary bypass surgery and atrial fibrillation were not independently associated with mortality; however, on multivariate analysis STS score was (HR 1.11; 95% CI 1.02-1.19; P = 0.01). Patients undergoing TAVR with 23 and 26 mm valves have similar clinical outcomes despite significant differences in baseline characteristics. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

All metal valve structure for gas systems

DOEpatents

Baker, Ray W.; Pawlak, Donald A.; Ramey, Alford J.

1984-11-13

A valve assembly with a resilient metal seat member is disclosed for providing a gas-tight seal in a gas handling system. The valve assembly also includes a valve element for sealing against the valve seat member; and an actuating means for operating the valve element. The valve seat member is a one-piece stainless steel ring having a central valve port and peripheral mounting flange, and an annular corrugation in between. A groove between the first and second ridges serves as a flexure zone during operation of the valve member and thus provides the seating pressure between the inner ridge or valve seat and the valve element. The outer annular ridge has a diameter less than said valve element to limit the seating motion of the valve element, preventing non-elastic deformation of the seat member.

All-metal valve structure for gas systems

DOEpatents

Baker, R.W.; Pawlak, D.A.; Ramey, A.J.

1982-06-10

A valve assembly with a resilient metal seat member is disclosed for providing a gas-tight seal in a gas handling system. The valve assembly also includes a valve element for sealing against the valve seat member; and an actuating means for operating the valve element. The valve seat member is a one-piece stainless steel ring having a central valve port and peripheral mounting flange, and an annular corrugation in between. A groove between the first and second ridges serves as a flexure zone during operation of the valve member and thus provides the seating pressure between the inner ridge or valve seat and the valve element. The outer annular ridge has a diameter less than said valve element to limit the seating motion of the valve element, preventing non-elastic deformation of the seat member.

Microblower assisted barometric valve

DOEpatents

Rossabi, Joseph; Hyde, Warren K.; Riha, Brian D.; Jackson, Dennis G.; Sappington, Frank

2005-12-06

A gas exchange apparatus is provided which provides for both passive fluid flow and blower associated fluid flow through a barometric valve. A battery powered blower is provided which allows for operation of the barometric valve during times when the barometric valve would otherwise be closed, and provides for enhanced volume of gas exchange.

Liquid rocket valve assemblies

NASA Technical Reports Server (NTRS)

1973-01-01

The design and operating characteristics of valve assemblies used in liquid propellant rocket engines are discussed. The subjects considered are as follows: (1) valve selection parameters, (2) major design aspects, (3) design integration of valve subassemblies, and (4) assembly of components and functional tests. Information is provided on engine, stage, and spacecraft checkout procedures.

British Gujarati Indian immigrants' and British Caucasians' beliefs about health and illness.

PubMed

Jobanputra, Rena; Furnham, Adrian

2005-12-01

This study examined cultural differences in beliefs about health and illness to explore differences in younger and older British Caucasians' and British Gujarati Indian immigrants' beliefs about health and illness. This study required a matched group consisting of first- and second-generation Gujarati Indian immigrants and native British Caucasians to complete a questionnaire assessing their beliefs concerning health and illness. Factor analysis of the health beliefs questionnaire identified six clear factors accounting for 36.04% of the variance. Subsequent ANCOVAs conducted on the factor scores, partialling out the demographic differences between the participants, revealed that Gujarati Indian immigrants agreed with items reflecting supernatural explanations of ill health more than indigenous British Caucasian participants. Older Indian immigrants also rated chance-related factors as more important than older Caucasian immigrants. There were no significant differences between the Gujarati Indian immigrants and British Caucasians in terms of attributions made to psychological factors and self-responsibility, social factors and life circumstances, medical treatment and physical vulnerability and the external environment. Findings are discussed in relation to the model proposed by Helman (2001) and the impact of migration on health beliefs systems; practical implications of the findings are also highlighted.

Aerosol penetration through respirator exhalation valves.

PubMed

Bellin, P; Hinds, W C

1990-10-01

Exhalation valves are a critical component of industrial respirators. They are designed to permit minimal inward leakage of air contaminants during inhalation and provide low resistance during exhalation. Under normal conditions, penetration of aerosol through exhalation valves is minimal. The exhalation valve is, however, a vulnerable component of a respirator and under actual working conditions may become dirty or damaged to the point of causing significant leakage. Aerosol penetration was measured for normal exhalation valves and valves compromised by paint or fine copper wires on the valve seat. Penetration increased with increasing wire diameter. A wire 250 microns in diameter allowed greater than 1% penetration into the mask cavity. Dirt or paint accumulated on the exhalation valve allowed a similar level of penetration. Work rate had little effect on observed penetration. Penetration decreased significantly with increasing aerosol particle size. The amount of material on the valve or valve seat necessary for significant (greater than 0.5%) inward leakage in a half-mask respirator could be readily observed by careful inspection of the exhalation valve and its seat in good lighting conditions.

Spool-Valve Pressure-Difference Regulator

NASA Technical Reports Server (NTRS)

Grasso, A. P.

1983-01-01

Valves maintain preset pressure difference between gas flows. Two spool valves connected by shaft move back and forth in response to changes in pressure in oxygen and hydrogen chambers. Spool-valve assembly acts to restore pressures to preset difference. By eliminating diaphragms, pressure exerted directly on external end of spool valve; however, forces and therefore sensitivity of assembly are reduced.

Valve-in-valve using an Edwards Sapien XT into a JenaValve in a patient with a low originating left coronary artery and a heavily calcified aorta.

PubMed

Fujita, Buntaro; Scholtz, Smita; Ensminger, Stephan

2016-04-01

Coronary obstruction during transcatheter aortic valve implantation is a potentially life-threatening complication. Most of the widely used transcatheter heart valves require a certain distance between the basal aortic annular plane and the origins of the coronary arteries. We report the case of a successful valve-in-valve procedure with an Edwards SAPIEN XT valve into a JenaValve as a bail-out procedure in a patient with a low originating left coronary artery and a heavily calcified aorta. © 2015 Wiley Periodicals, Inc.

European Society of Cardiology Council for Cardiology Practice worldwide survey of transcatheter aortic valve implantation beliefs and practices.

PubMed

Asteggiano, Riccardo; Bramlage, Peter; Richter, Dimitrios J

2018-04-01

Background Transcatheter aortic valve implantation (TAVI) continues to gain popularity in the management of patients with severe aortic stenosis (SAS). Distribution of resources to maximise appropriate use remains a priority. Design & methods To determine the current perceptions and behaviours regarding SAS patient management, an 18-point multiple-choice questionnaire was distributed to European Society of Cardiology (ESC) Council for Cardiology Practice (CCP) e-journal and/or electronic newsletter subscribers. Respondents to all questions were considered. Sub-analyses based on respondent age, practice setting and geographical location were performed. Results Of 1245 full respondents, 41.5% were aged ≥ 51 years, 22.7% were aged 41-50 years and 35.8% were aged ≤ 40 years. The majority were located in Europe (77.5%), followed by Asia/Oceania (11.6%), America (7.6%) and Africa (3.4%). In-hospital and out-of-hospital cardiologists accounted for 57.4% of and 28.5% of the sample, respectively, with the remainder being general practitioners/other. The majority of respondents (70.1%) claimed to diagnose between one and five cases of SAS per month. Free access to TAVI was reported by 41.2%, being less common for those aged ≤ 40 years (32.7%; p < 0.001), those located in Asia/Oceania, America and Africa (20.1%, 18.1% and 2.4%, respectively; p < 0.01 in each case) and in-hospital compared to out-of-hospital cardiologists (35.7% vs. 54.5%, respectively; p < 0.001). The most common reason for not referring a patient for an aortic valve intervention was assessment that the patient was high risk/non-operable (55.5%), followed by short life expectancy (30.5%). The most common reason for referring a patient for TAVI over surgical replacement was surgical risk score (56.9%). The most commonly perceived main complication of TAVI was stroke (28.9%), while the most frequently selected main benefit was improvement in quality of life (37.2%). A high

Mechanisms of mechanical heart valve cavitation: investigation using a tilting disk valve model.

PubMed

He, Z; Xi, B; Zhu, K; Hwang, N H

2001-09-01

The induction of mechanical heart valve (MHV) cavitation was investigated using a 27 mm Medtronic Hall (MH27) tilting disk valve. The MH27 valve was mounted in the mitral position of a simulating pulse flow system, and stroboscopic lighting used to visualize cavitation bubbles on the occluder inflow surface at the instant of valve closure. MHV cavitation was monitored using a digital camera with 0.04 mm/pixel resolution sufficient to render the tiny bubbles clearly visible on the computer monitor screen. Cavitation on MH27 valve was classified as five types according to the time, site and shape of the cavitation bubbles. Valve cavitation occurred at the instant of occluder impact with the valve seat at closing. The impact motion was subdivided into three temporal phases: (i) squeezing flow; (ii) elastic collision; and (iii) leaflet rebound. MHV cavitation caused by vortices was found to be initiated by the squeezing jet and/or by the transvalvular leakage jets. By using a tension wave which swept across the occluder surface immediately upon elastic impact, nuclei in the vortex core were expanded to form cavitation bubbles. Analysis of the shape and location of the cavitation bubbles permitted a better understanding of MHV cavitation mechanisms, based on the fluid dynamics of jet vortex and tension wave propagations.

Patients receiving anti-TNF therapies experience clinically important improvements in RA-related fatigue: results from the British Society for Rheumatology Biologics Register for Rheumatoid Arthritis.

PubMed

Druce, Katie L; Jones, Gareth T; Macfarlane, Gary J; Basu, Neil

2015-06-01

Pro-inflammatory cytokines such as TNF-α are important in the pathogenesis of fatigue in conditions such as RA. This study aimed to determine whether fatigue improved in a cohort of RA patients with clinically relevant fatigue commencing anti-TNF-α therapy and, if so, to identify predictors of improvement. Participants recruited to a long-term observational cohort study (the British Society for Rheumatology Biologics Register for RA) provided information on fatigue using the 36-item Short Form Health Survey (SF-36) vitality subscale. The prevalence of severe baseline fatigue (SF-36 vitality ≤12.5) was calculated and improvements, considered as (i) absolute values and (ii) improvement from severe to non-severe fatigue (SF-36 vitality >12.5), were examined 6 months subsequently. A comprehensive set of putative predictors of fatigue improvement were evaluated using multivariable logistic regression. In 6835 participants the prevalence of severe baseline fatigue was 38.8%. Of those with severe fatigue, 70% reported clinically relevant improvement and 66% moved to the non-severe fatigue category (i.e. improvers). The mean change for improvers was three times the minimum clinically important difference for improvement (33.0 U). Independent baseline predictors of improvement were female sex [odds ratio (OR) 1.3 (95% CI 1.1, 1.7)], not being unemployed due to ill health [OR 1.5 (95% CI 1.2, 1.7)], low disability [OR 1.2 (95% CI 1.001, 1.5)], seropositivity [OR 1.2 (95% CI 0.98, 1.4)], not using steroids [OR 1.2 (95% CI 1.03, 1.5)], no history of hypertension [OR 1.4 (95% CI 1.1, 1.6)] or depression [OR 1.3 (95% CI 1.1, 1.5)] and good mental health [SF-36 mental health subscale >35; OR 1.4 (95% CI 1.2, 1.7)]. Fatigued RA patients reported substantial improvement in their fatigue after commencing anti-TNF-α therapy. Further, a number of clinical and psychosocial baseline factors identified those most likely to improve, supporting future stratified approaches to RA

Bioprinting a cardiac valve.

PubMed

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. Copyright © 2015 Elsevier Inc. All rights reserved.

Fluid Dynamic Characterization of a Polymeric Heart Valve Prototype (Poli-Valve) tested under Continuous and Pulsatile Flow Conditions

PubMed Central

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

Fluid dynamic characterization of a polymeric heart valve prototype (Poli-Valve) tested under continuous and pulsatile flow conditions.

PubMed

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.

Association between aortic valve calcification measured on non-contrast computed tomography and aortic valve stenosis in the general population.

PubMed

Paulsen, Niels Herluf; Carlsen, Bjarke Bønløkke; Dahl, Jordi Sanchez; Carter-Storch, Rasmus; Christensen, Nicolaj Lyhne; Khurrami, Lida; Møller, Jacob Eifer; Lindholt, Jes Sandal; Diederichsen, Axel Cosmus Pyndt

2016-01-01

Aortic valve calcification (AVC) measured on non-contrast computed tomography (CT) has shown correlation to severity of aortic valve stenosis (AS) and mortality in patients with known AS. The aim of this study was to determine the association of CT verified AVC and subclinical AS in a general population undergoing CT. CT scans from 566 randomly selected male participants (age 65-74) in the Danish cardiovascular screening study (DANCAVAS) were analyzed for AVC. All participants with a moderately or severely increased AVC score (≥300 arbitrary units (AU)) and a matched control group were invited for a supplementary echocardiography. AS was graded by indexed aortic valve area (AVAi) on echocardiography as moderate 0.6-0.85 cm(2)/m(2) and severe < 0.6 cm(2)/m(2), respectively. ROC- and regression analyses were performed. Due to prior valve surgery, and artifacts from ICD leads 16 individuals were excluded from the AVC scoring. Moderate or severe increased AVC was observed in 10.7% (95% CI: 8.4-13.7). Echocardiography was performed in 101 individuals; 32.7% (95% CI: 21.8 to 46.0) with moderate or high AVC score had moderate or severe AS, while none with no or low AVC. A ROC analysis defined an AVC score ≥588 AU to be suggestive of moderate or severe AS (AUC 0.89 ± 0.04, sensitivity 83% and specificity 87%). In the univariate analyses, AVC was the only variable significantly associated with AS. This study indicates an association between CT verified AVC and subclinical AS. Copyright © 2016 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

Low energy high pressure miniature screw valve

DOEpatents

Fischer, Gary J [Sandia Park, NM; Spletzer, Barry L [Albuquerque, NM

2006-12-12

A low energy high pressure screw valve having a valve body having an upper portion and a lower portion, said lower portion of said valve body defining an inlet flow passage and an outlet flow passage traversing said valve body to a valve seat, said upper portion of said valve body defining a cavity at said valve seat, a diaphragm restricting flow between said upper portion of said valve body and said lower portion, said diaphragm capable of engaging said valve seat to restrict fluid communication between said inlet passage and said outlet passage, a plunger within said cavity supporting said diaphragm, said plunger being capable of engaging said diaphragm with said valve seat at said inlet and outlet fluid passages, said plunger being in point contact with a drive screw having threads engaged with opposing threads within said upper portion of said valve body such engagement allowing motion of said drive screw within said valve body.

Mitral valve surgery - minimally invasive

MedlinePlus

... flow. Your valve has developed an infection (infectious endocarditis). You have severe mitral valve prolapse that is ... function. Damage to your heart valve from infection (endocarditis). A minimally invasive procedure has many benefits. There ...

49 CFR 195.116 - Valves.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 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 the...

Evolving trends in aortic valve replacement: A statewide experience.

PubMed

Kim, Karen M; Shannon, Francis; Paone, Gaetano; Lall, Shelly; Batra, Sanjay; Boeve, Theodore; DeLucia, Alphonse; Patel, Himanshu J; Theurer, Patricia F; He, Chang; Clark, Melissa J; Sultan, Ibrahim; Deeb, George Michael; Prager, Richard L

2018-06-17

Transcatheter aortic valve replacement (TAVR) is an alternative to surgical aortic valve replacement (SAVR) for the treatment of aortic stenosis in patients at intermediate, high, and extreme risk for mortality from SAVR. We examined recent trends in aortic valve replacement (AVR) in Michigan. The Michigan Society of Thoracic and Cardiovascular Surgeons Quality Collaborative (MSTCVS-QC) database was used to determine the number of SAVR and TAVR cases performed from January 2012 through June 2017. Patients were divided into low, intermediate, high, and extreme risk groups based on STS predicted risk of mortality (PROM). TAVR patients in the MSTCVS-QC database were also matched with those in the Transcatheter Valve Therapy Registry to determine their Heart Team-designated risk category. During the study period 9517 SAVR and 4470 TAVR cases were performed. Total annual AVR volume increased by 40.0% (from 2086 to 2920), with a 13.3% decrease in number of SAVR cases (from 1892 to 1640) and a 560% increase in number of TAVR cases (from 194 to 1280). Greater than 90% of SAVR patients had PROM ≤8%. While >70% of TAVR patients had PROM ≤ 8%, they were mostly designated as high or extreme risk by a Heart Team. During the study period, SAVR volume gradually declined and TAVR volume dramatically increased. This was mostly due to a new group of patients with lower STS PROM who were designated as higher risk by a Heart Team due to characteristics not completely captured by the STS PROM score. © 2018 Wiley Periodicals, Inc.

Solenoid valve performance characteristics studied

NASA Technical Reports Server (NTRS)

Abe, J. T.; Blackburn, S.

1970-01-01

Current and voltage waveforms of a solenoid coil are recorded as the valve opens and closes. Analysis of the waveforms with respect to time and the phase of the valve cycle accurately describes valve performance.

100. INTERIOR OF SKID 9A: VENT VALVE AND RELIEF VALVE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

100. INTERIOR OF SKID 9A: VENT VALVE AND RELIEF VALVE FOR RAPID-LOAD LIQUID OXYGEN TANK - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

Thermostatic Valves Containing Silicone-Oil Actuators

NASA Technical Reports Server (NTRS)

Bhandari, Pradeep; Birur, Gajanana C.; Bame, David P.; Karlmann, Paul B.; Prina, Mauro; Young, William; Fisher, Richard

2009-01-01

Flow-splitting and flow-mixing thermally actuated spool valves have been developed for controlling flows of a heat-transfer fluid in a temperature-regulation system aboard the Mars Science Laboratory (MSL) rover. Valves like these could also be useful in terrestrial temperature-regulation systems, including automobile air-conditioning systems and general refrigeration systems. These valves are required to provide smoother actuation over a wider temperature range than the flow-splitting, thermally actuated spool valves used in the Mars Explorer Rover (MER). Also, whereas the MER valves are unstable (tending to oscillate) in certain transition temperature ranges, these valves are required not to oscillate. The MER valves are actuated by thermal expansion of a wax against spring-loaded piston rods (as in common automotive thermostats). The MSL valves contain similar actuators that utilize thermal expansion of a silicone oil, because silicone-oil actuators were found to afford greater and more nearly linear displacements, needed for smoother actuation, over the required wider temperature range. The MSL valves also feature improved spool designs that reflect greater understanding of fluid dynamics, consideration of pressure drops in valves, and a requirement for balancing of pressures in different flow branches.

[Status of aortic valve reconstruction and Ross operation in aortic valve diseases].

PubMed

Sievers, Hans H

2002-08-01

At first glance the aortic valve is a relative simple valve mechanism connecting the left ventricle and the ascending aorta. Detailed analysis of the different components of the aortic valve including the leaflets and sinuses revealed a complex motion of each part leading to a perfect durable valve mechanism at rest and during exercise. Theoretically, the reconstruction or imitation of these structures in patients with aortic valve disease should lead to optimal results. Prerequisite is the exact knowledge of the important functional characteristics of the aortic valve. The dynamic behavior of the aortic root closely harmonizing with the leaflets not only warrants stress minimizing and valve durability, but also optimizes coronary flow, left ventricular function and aortic impedance. The newly discovered contractile capacity of the leaflets and the root components are important for tuning the dynamics. Isolated reconstruction of the aortic valve such as decalcification, commissurotomy, plication of ring or leaflets of a tricuspid aortic valve and cusp extension are seldom indicated in contrast to the reconstruction of the bicuspid insufficient valve. Proper indication and skilled techniques lead to excellent hemodynamic and clinical intermediate-term result up to 7 years after reconstruction. Latest follow-up revealed a mean aortic insufficiency of 0.7, maximal pressure gradient of 11.4 +/- 8.5 mm Hg with zero hospital or late mortality, reoperation or thromboembolic events in 22 patients. The reconstructive techniques for aortic root aneurysm and/or type A dissection according to David or Yacoub have become routine procedures in the last 10 years. The hemodynamic and clinical results are excellent with low reoperation rate and very low risk of thromboembolism. Generally, a maximal diameter of the root of 5 cm is indicative for performing the operation. In patients with Marfan's syndrome the reconstruction should be advanced even with smaller diameters especially

Options for Heart Valve Replacement

MedlinePlus

... which may include human or animal donor tissue) Ross Procedure — “Borrowing” your healthy valve and moving it ... Considerations for Surgery Medications Valve Repair Valve Replacement - Ross Procedure - Newer Surgery Options - What is TAVR? - Types ...

Damage-Free Relief-Valve Disassembly

NASA Technical Reports Server (NTRS)

Haselmaier, H.

1986-01-01

Tool safely disassembles relief valves without damage to sensitive parts. Relief-valve disassembly tool used to extract valve nozzle from its housing. Holding device on tool grops nozzle. When user strikes hammer against impact disk, holding device pulls nozzle from press fit. Previously, nozzle dislodged by striking spindle above it, but practice often damaged retaining screw. New tool removes nozzle directly. With minor modifications, tool adapted to valves from different manufacturers.

Aortic valve replacement for papillary fibroelastoma.

PubMed

Arikan, Ali Ahmet; Omay, Oğuz; Aydın, Fatih; Kanko, Muhip; Gür, Sibel; Derviş, Emir; Yılmaz, Cansu Eda; Müezzinoğlu, Bahar

2017-06-01

Surgery is indicated for symptomatic patients with papillary fibroelastomas (PFE) on the aortic valve. The valve is commonly spared during tumor excision. Rarely, aortic valve replacement (AVR) is needed. We present a case requiring AVR for an aortic valve PFE and review the literature to determine the risk factors for failure of aortic valve-sparing techniques in patients with PFE. © 2017 Wiley Periodicals, Inc.

Balancing the risks and benefits associated with cosmetic dentistry - a joint statement by UK specialist dental societies.

PubMed

Alani, A; Kelleher, M; Hemmings, K; Saunders, M; Hunter, M; Barclay, S; Ashley, M; Djemal, S; Bishop, K; Darbar, U; Briggs, P; Fearne, J

2015-05-08

Cosmetic dentistry has become increasingly popular, largely as a result of social trends and increased media coverage. This understandable desire for the alleged 'perfect smile' needs to be tempered with an appropriate awareness of the significant risks associated with invasive cosmetic procedures such as veneers and crowns. Patients need to be properly informed that elective removal of healthy enamel and dentine can result in pulpal injury and poorer periodontal health in the longer term, particularly if they are young. The duty of candour means that they ought to be informed that aggressive reduction of sound tooth tissue is not biologically neutral and results in structural weakening of their teeth. Less invasive procedures such as bleaching on its own or for example, combined with direct resin composite bonding, can satisfy many patient's demands, while still being kinder to teeth and having much better fall-back positions for their future requirements. It is the opinion of the British Endodontic Society, British Society for Restorative Dentistry, Restorative Dentistry UK, Dental Trauma UK, British Society of Prosthodontics and the British Society of Paediatric Dentistry that elective invasive cosmetic dental treatments can result in great benefit to patients, but that some aggressive treatments used to achieve them can produce significant morbidities in teeth which were previously healthy. This is a worrying and growing problem with many ethical, legal and biologic aspects, but many adverse outcomes for patients who request cosmetic dental improvements are preventable by using biologically safer initial approaches to treatment planning and its provision.

46 CFR 56.20-9 - Valve construction.

Code of Federal Regulations, 2011 CFR

2011-10-01

...) motion of the handwheel or operating lever as seen by one facing the end of the valve stem. Each gate, globe, and angle valve must generally be of the rising-stem type, preferably with the stem threads... nonrising-stem valve will be acceptable. Each nonrising-stem valve, lever-operated valve, or other valve...

46 CFR 56.20-9 - Valve construction.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) motion of the handwheel or operating lever as seen by one facing the end of the valve stem. Each gate, globe, and angle valve must generally be of the rising-stem type, preferably with the stem threads... nonrising-stem valve will be acceptable. Each nonrising-stem valve, lever-operated valve, or other valve...

46 CFR 56.20-9 - Valve construction.

Code of Federal Regulations, 2012 CFR

2012-10-01

...) motion of the handwheel or operating lever as seen by one facing the end of the valve stem. Each gate, globe, and angle valve must generally be of the rising-stem type, preferably with the stem threads... nonrising-stem valve will be acceptable. Each nonrising-stem valve, lever-operated valve, or other valve...

46 CFR 56.20-9 - Valve construction.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) motion of the handwheel or operating lever as seen by one facing the end of the valve stem. Each gate, globe, and angle valve must generally be of the rising-stem type, preferably with the stem threads... nonrising-stem valve will be acceptable. Each nonrising-stem valve, lever-operated valve, or other valve...

Inverse spin-valve effect in nanoscale Si-based spin-valve devices

NASA Astrophysics Data System (ADS)

Hiep, Duong Dinh; Tanaka, Masaaki; Hai, Pham Nam

2017-12-01

We investigated the spin-valve effect in nano-scale silicon (Si)-based spin-valve devices using a Fe/MgO/Ge spin injector/detector deposited on Si by molecular beam epitaxy. For a device with a 20 nm Si channel, we observed clear magnetoresistance up to 3% at low temperature when a magnetic field was applied in the film plane along the Si channel transport direction. A large spin-dependent output voltage of 20 mV was observed at a bias voltage of 0.9 V at 15 K, which is among the highest values in lateral spin-valve devices reported so far. Furthermore, we observed that the sign of the spin-valve effect is reversed at low temperatures, suggesting the possibility of a spin-blockade effect of defect states in the MgO/Ge tunneling barrier.

Valve malfunction detection apparatus

NASA Astrophysics Data System (ADS)

Burley, Richard K.

1993-07-01

A detection system is provided for sensing a malfunction of a valve having an outlet connected to an end of a first pipe through which pressurized fluid may be flowed in a downstream direction away from the valve. The system includes a bypass pipe connected at its opposite ends to the first pipe and operative to bypass a portion of the fluid flow therethrough around a predetermined section thereof. A housing is interiorly divided by a flexible diaphragm into first and second opposite chambers which are respectively communicated with the first pipe section and the bypass pipe, the diaphragm being spring-biased toward the second chamber. The diaphragm housing cooperates with check valves and orifices connected in the two pipes to create and maintain a negative pressure in the first pipe section in response to closure of the valve during pressurized flow through the first pipe. A pressure switch senses the negative pressure and transmits a signal indicative thereof to a computer. Upon cessation of the signal while the valve is still closed, the computer responsively generates a signal indicating that the valve, or another portion of the detection system, is leaking.

Valve malfunction detection apparatus

NASA Technical Reports Server (NTRS)

Burley, Richard K. (Inventor)

1993-01-01

A detection system is provided for sensing a malfunction of a valve having an outlet connected to an end of a first pipe through which pressurized fluid may be flowed in a downstream direction away from the valve. The system includes a bypass pipe connected at its opposite ends to the first pipe and operative to bypass a portion of the fluid flow therethrough around a predetermined section thereof. A housing is interiorly divided by a flexible diaphragm into first and second opposite chambers which are respectively communicated with the first pipe section and the bypass pipe, the diaphragm being spring-biased toward the second chamber. The diaphragm housing cooperates with check valves and orifices connected in the two pipes to create and maintain a negative pressure in the first pipe section in response to closure of the valve during pressurized flow through the first pipe. A pressure switch senses the negative pressure and transmits a signal indicative thereof to a computer. Upon cessation of the signal while the valve is still closed, the computer responsively generates a signal indicating that the valve, or another portion of the detection system, is leaking.

Electro-Mechanical Coaxial Valve

NASA Technical Reports Server (NTRS)

Patterson, Paul R (Inventor)

2004-01-01

Coaxial valves usually contain only one moving part. It has not been easy, then, to provide for electric motor actuation. Many actuators being proposed involve designs which lead to bulky packages. The key facing those improving coaxial valves is the provision of suitable linear actuation. The valve herein indudes a valve housing with a flow channel there-through. Arranged in the flow channel is a closing body. In alignment with the closing body is a ball screw actuator which includes a ball nut and a cylindrical screw. The ball nut sounds a threaded portion of the cylindrical screw. The cylindrical screw is provided with a passageway there-through through which fluid flows. The cylindrical screw is disposed in the flow channel to become a control tube adapted to move toward and away from the valve seat. To rotate the ball nut an actuating drive is employed driven by a stepper motor.

Valve for controlling solids flow

DOEpatents

Feldman, David K.

1980-01-01

A fluidized solids control valve is disclosed that is particularly well adapted for use with a flow of coal or char that includes both large particles and fines. The particles may or may not be fluidized at various times during the operation. The valve includes a tubular body that terminates in a valve seat covered by a normally closed closure plate. The valve body at the seat and the closure plate is provided with aligned longitudinal slots that receive a pivotally supported key plate. The key plate is positionable by an operator in inserted, intermediate and retracted positions respecting the longitudinal slot in the valve body. The key plate normally closes the slot within the closure plate but is shaped and aligned obliquely to the longitudinal slot within the valve body to provide progressively increasing slot openings between the inserted and retracted positions. Transfer members are provided between the operator, key plate and closure plate to move the closure plate into an open position only when the key plate is retracted from the longitudinal slot within the valve body.

Optothermally actuated capillary burst valve

NASA Astrophysics Data System (ADS)

Eriksen, Johan; Bilenberg, Brian; Kristensen, Anders; Marie, Rodolphe

2017-04-01

We demonstrate the optothermal actuation of individual capillary burst valves in an all-polymer microfluidic device. The capillary burst valves are realised in a planar design by introducing a fluidic constriction in a microfluidic channel of constant depth. We show that a capillary burst valve can be burst by raising the temperature due to the temperature dependence of the fluid surface tension. We address individual valves by using a local heating platform based on a thin film of near infrared absorber dye embedded in the lid used to seal the microfluidic device [L. H. Thamdrup et al., Nano Lett. 10, 826-832 (2010)]. An individual valve is burst by focusing the laser in its vicinity. We demonstrate the capture of single polystyrene 7 μm beads in the constriction triggered by the bursting of the valve.

SLM Produced Hermetically Sealed Isolation Valve

NASA Technical Reports Server (NTRS)

Richard, James

2014-01-01

Marshall Space Flight Center (MSFC) has developed a valve concept to replace traditional pyrotechnic-driven isolation valves. This paper will describe the valve design and development process. The valve design uses a stem/wedge to support a disk inside the valve. That disk hermetically seals the pressurized fluids. A release mechanism holds the stem/wedge and a large spring in place. When required to open, a solenoid is energized and pulls the release mechanism allowing the spring to pull the stem/wedge away from the disk. Now the disk is unsupported and the pressure ruptures the disk allowing flow to the outlet of the valve. This paper will provide details of this design, describe the development testing, and show the results from the valve level tests performed. Also, a trade study is presented to show the advantages of this design to a conventional pyrotechnic-based valve.

SLM Produced Hermetically Sealed Isolation Valve

NASA Technical Reports Server (NTRS)

Richard, James A.

2014-01-01

Marshall Space Flight Center (MSFC) has developed a valve concept to replace traditional pyrotechnic driven isolation valves. This paper will describe the valve design and development process. The valve design uses a stem/wedge to support a disk inside the valve. That disk hermetically seals the pressurized fluids. A release mechanism holds the stem/wedge and a large spring in place. When required to open, a solenoid is energized and pulls the release mechanism allowing the spring to pull the stem/wedge away from the disk. Now the disk is unsupported and the pressure ruptures the disk allowing flow to the outlet of the valve. This paper will provide details of this design, describe the development testing, and show the results from the valve level tests performed. Also, a trade study is presented to show the advantages of this design to a conventional pyrotechnic based valve.

Semi-active compressor valve

DOEpatents

Brun, Klaus; Gernentz, Ryan S.

2010-07-27

A method and system for fine-tuning the motion of suction or discharge valves associated with cylinders of a reciprocating gas compressor, such as the large compressors used for natural gas transmission. The valve's primary driving force is conventional, but the valve also uses an electromagnetic coil to sense position of the plate (or other plugging element) and to provide an opposing force prior to impact.

Aortic valve stenosis and aortic diameters determine the extent of increased wall shear stress in bicuspid aortic valve disease.

PubMed

Farag, Emile S; van Ooij, Pim; Planken, R Nils; Dukker, Kayleigh C P; de Heer, Frederiek; Bouma, Berto J; Robbers-Visser, Danielle; Groenink, Maarten; Nederveen, Aart J; de Mol, Bas A J M; Kluin, Jolanda; Boekholdt, S Matthijs

2018-02-16

Use of 4-dimensional flow magnetic resonance imaging (4D-flow MRI) derived wall shear stress (WSS) heat maps enables identification of regions in the ascending aorta with increased WSS. These regions are subject to dysregulation of the extracellular matrix and elastic fiber degeneration, which is associated with aortic dilatation and dissection. To evaluate the effect of the presence of aortic valve stenosis and the aortic diameter on the peak WSS and surface area of increased WSS in the ascending aorta. Prospective. In all, 48 bicuspid aortic valve (BAV) patients (38.1 ± 12.4 years) and 25 age- and gender-matched healthy individuals. Time-resolved 3D phase contrast MRI with three-directional velocity encoding at 3.0T. Peak systolic velocity, WSS, and aortic diameters were assessed in the ascending aorta and 3D heat maps were used to identify regions with elevated WSS. Comparisons between groups were performed by t-tests. Correlations were investigated by univariate and multivariate regression analysis. Elevated WSS was present in 15 ± 11% (range; 1-35%) of the surface area of the ascending aorta of BAV patients with aortic valve stenosis (AS) (n = 10) and in 6 ± 8% (range; 0-31%) of the ascending aorta of BAV patients without AS (P = 0.005). The mid-ascending aortic diameter negatively correlated with the peak ascending aortic WSS (R = -0.413, P = 0.004) and the surface area of elevated WSS (R = -0.419, P = 0.003). Multivariate linear regression analysis yielded that the height of peak WSS and the amount of elevated WSS depended individually on the presence of aortic valve stenosis and the diameter of the ascending aorta. The extent of increased WSS in the ascending aorta of BAV patients depends on the presence of aortic valve stenosis and aortic dilatation and is most pronounced in the presence of AS and a nondilated ascending aorta. 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018. © 2018 The Authors Journal of

Surgical or Transcatheter Aortic-Valve Replacement in Intermediate-Risk Patients.

PubMed

Reardon, Michael J; Van Mieghem, Nicolas M; Popma, Jeffrey J; Kleiman, Neal S; Søndergaard, Lars; Mumtaz, Mubashir; Adams, David H; Deeb, G Michael; Maini, Brijeshwar; Gada, Hemal; Chetcuti, Stanley; Gleason, Thomas; Heiser, John; Lange, Rüdiger; Merhi, William; Oh, Jae K; Olsen, Peter S; Piazza, Nicolo; Williams, Mathew; Windecker, Stephan; Yakubov, Steven J; Grube, Eberhard; Makkar, Raj; Lee, Joon S; Conte, John; Vang, Eric; Nguyen, Hang; Chang, Yanping; Mugglin, Andrew S; Serruys, Patrick W J C; Kappetein, Arie P

2017-04-06

Although transcatheter aortic-valve replacement (TAVR) is an accepted alternative to surgery in patients with severe aortic stenosis who are at high surgical risk, less is known about comparative outcomes among patients with aortic stenosis who are at intermediate surgical risk. We evaluated the clinical outcomes in intermediate-risk patients with severe, symptomatic aortic stenosis in a randomized trial comparing TAVR (performed with the use of a self-expanding prosthesis) with surgical aortic-valve replacement. The primary end point was a composite of death from any cause or disabling stroke at 24 months in patients undergoing attempted aortic-valve replacement. We used Bayesian analytical methods (with a margin of 0.07) to evaluate the noninferiority of TAVR as compared with surgical valve replacement. A total of 1746 patients underwent randomization at 87 centers. Of these patients, 1660 underwent an attempted TAVR or surgical procedure. The mean (±SD) age of the patients was 79.8±6.2 years, and all were at intermediate risk for surgery (Society of Thoracic Surgeons Predicted Risk of Mortality, 4.5±1.6%). At 24 months, the estimated incidence of the primary end point was 12.6% in the TAVR group and 14.0% in the surgery group (95% credible interval [Bayesian analysis] for difference, -5.2 to 2.3%; posterior probability of noninferiority, >0.999). Surgery was associated with higher rates of acute kidney injury, atrial fibrillation, and transfusion requirements, whereas TAVR had higher rates of residual aortic regurgitation and need for pacemaker implantation. TAVR resulted in lower mean gradients and larger aortic-valve areas than surgery. Structural valve deterioration at 24 months did not occur in either group. TAVR was a noninferior alternative to surgery in patients with severe aortic stenosis at intermediate surgical risk, with a different pattern of adverse events associated with each procedure. (Funded by Medtronic; SURTAVI ClinicalTrials.gov number

Mitral valve-sparing procedures and prosthetic heart valve failure: A case report

PubMed Central

Khan, Nasir A; Butany, Jagdish; Leong, Shaun W; Rao, Vivek; Cusimano, Robert J; Ross, Heather J

2009-01-01

Prosthetic heart valve dysfunction due to thrombus or pannus formation can be a life-threatening complication. The present report describes a 47-year-old woman who developed valvular cardiomyopathy after chorda-sparing mitral valve replacement, and subsequently underwent heart transplantation for progressive heart failure. The explanted mitral valve prosthesis showed significant thrombus and pannus leading to reduced leaflet mobility and valvular stenosis. The present report illustrates the role of the subvalvular apparatus and pannus in prosthesis dysfunction. PMID:19279993

Liquid rocket pressure regulators, relief valves, check valves, burst disks, and explosive valves. [design techniques and practices

NASA Technical Reports Server (NTRS)

1973-01-01

The development of and operational programs for effective use in design are presented for liquid rocket pressure regulators, relief valves, check valves, burst disks, and explosive valves. A review of the total design problem is presented, and design elements are identified which are involved in successful design. Current technology pertaining to these elements is also described. Design criteria are presented which state what rule or standard must be imposed on each essential design element to assure successful design. These criteria serve as a checklist of rules for a project manager to use in guiding a design or in assessing its adequacy. Recommended practices are included which state how to satisfy each of the criteria.

Simple Check Valves for Microfluidic Devices

NASA Technical Reports Server (NTRS)

Willis, Peter A.; Greer, Harold F.; Smith, J. Anthony

2010-01-01

A simple design concept for check valves has been adopted for microfluidic devices that consist mostly of (1) deformable fluorocarbon polymer membranes sandwiched between (2) borosilicate float glass wafers into which channels, valve seats, and holes have been etched. The first microfluidic devices in which these check valves are intended to be used are micro-capillary electrophoresis (microCE) devices undergoing development for use on Mars in detecting compounds indicative of life. In this application, it will be necessary to store some liquid samples in reservoirs in the devices for subsequent laboratory analysis, and check valves are needed to prevent cross-contamination of the samples. The simple check-valve design concept is also applicable to other microfluidic devices and to fluidic devices in general. These check valves are simplified microscopic versions of conventional rubber- flap check valves that are parts of numerous industrial and consumer products. These check valves are fabricated, not as separate components, but as integral parts of microfluidic devices. A check valve according to this concept consists of suitably shaped portions of a deformable membrane and the two glass wafers between which the membrane is sandwiched (see figure). The valve flap is formed by making an approximately semicircular cut in the membrane. The flap is centered over a hole in the lower glass wafer, through which hole the liquid in question is intended to flow upward into a wider hole, channel, or reservoir in the upper glass wafer. The radius of the cut exceeds the radius of the hole by an amount large enough to prevent settling of the flap into the hole. As in a conventional rubber-flap check valve, back pressure in the liquid pushes the flap against the valve seat (in this case, the valve seat is the adjacent surface of the lower glass wafer), thereby forming a seal that prevents backflow.

Transfemoral transcatheter aortic valve insertion-related intraoperative morbidity: Implications of the minimalist approach.

PubMed

Greason, Kevin L; Pochettino, Alberto; Sandhu, Gurpreet S; King, Katherine S; Holmes, David R

2016-04-01

Transfemoral transcatheter aortic valve insertion may be performed in a catheterization laboratory (ie, the minimalist approach). It seems reasonable when considering this approach to avoid it in patients at risk for intraoperative morbidity that would require surgical intervention. We hypothesized that it would be possible to associate baseline characteristics with such morbidity, which would help heart teams select patients for the minimalist approach. We reviewed the records of 215 consecutive patients who underwent transfemoral transcatheter aortic valve insertion with a current commercially available device from November 2008 through July 2015. Demographic characteristics of the patients included a mean age of 78.9 ± 10.6 years, female sex in 73 patients (34.0%), and a mean Society of Thoracic Surgeons predicted risk of mortality of 8.7% ± 5.4%. Valve prostheses were balloon-expandable in 126 patients (58.6%) and self-expanding in 89 patients (41.4%). Significant intraoperative morbidity occurred in 22 patients (10.2%) and included major vascular injury in 12 patients (5.6%), hemodynamic compromise requiring cardiopulmonary bypass support in 4 patients (1.9%), cardiac tamponade requiring intervention in 3 patients (1.4%), ventricular valve embolization in 2 patients (0.9%), and inability to obtain percutaneous access requiring open vascular access in 1 patient (0.5%). Intraoperative morbidity was similarly distributed across all valve types (P = .556) and sheath sizes (P = .369). There were no baseline patient characteristics predictive of intraoperative morbidity. Patient and valve characteristics are not predictive of significant intraoperative morbidity during transfemoral transcatheter aortic valve insertion. The finding has implications for patient selection for the minimalist approach. Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Long-Term Mortality Effect of Early Pacemaker Implantation After Surgical Aortic Valve Replacement.

PubMed

Greason, Kevin L; Lahr, Brian D; Stulak, John M; Cha, Yong-Mei; Rea, Robert F; Schaff, Hartzell V; Dearani, Joseph A

2017-10-01

The need for pacemaker implantation is a well-described complication of aortic valve replacement. Not so well described is the effect such an event has on long-term outcome. This study reviewed a 21-year experience at the Mayo Clinic (Rochester, Minnesota) with aortic valve replacement to understand the influence of early postoperative pacemaker implantation on long-term mortality rates more clearly. This study retrospectively reviewed the records of 5,842 patients without previous pacemaker implantation who underwent surgical aortic valve replacement from January 1993 through June 2014. The median age of these patients was 73 years (range, 65 to 79 years), the median ejection fraction was 62% (range, 53% to 68%), 3,853 patients were male (66%), and coronary artery bypass graft operation was performed in 2,553 (44%) of the patients studied. Early pacemaker implantation occurred in 146 patients (2.5%) within 30 days of surgical aortic valve replacement. The median follow-up of patients was 11.1 years (range, 5.8 to 16.5 years), and all-cause mortality rates were 2.4% at 30 days, 6.4% at 1 year, 23.1% at 5 years, 48.3% at 10 years, and 67.9% at 15 years postoperatively. Early pacemaker implantation was associated with an increased risk of death after multivariable adjustment for baseline patients' characteristics (hazard ratio, 1.49; 95% confidence interval, 1.20, 1.84; p < 0.001). Early pacemaker implantation as a complication of surgical aortic valve replacement is associated with an increased risk of long-term death. Valve replacement-related pacemaker implantation rates should be important considerations with respect to new valve replacement paradigms, especially in younger and lower-risk patients. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Programming jammed Codman Hakim programmable valves: study of an explanted valve and successful programming in a patient.

PubMed

Wong, Sui-To; Wen, Eleanor; Fong, Dawson

2013-08-01

Malfunction of a Codman Hakim programmable valve due to jamming of its programmable component may necessitate shunt revision. The authors report a method for programming jammed Codman Hakim programmable valves by using a Strata II magnet and additional neodymium magnets. The programming method was derived after studying a jammed valve in the laboratory that was explanted from an 10-year-old boy with a history of fourth ventricle ependymoma. Programming the explanted valve with a Codman programmer failed, but rotating a Strata II magnet above the valve resulted in rotation of the spiral cam in the valve. It was found that the Strata II magnet could be used to program the jammed valve by rotating the magnet 90° or multiples of 90° above the valve. The strength of the magnetic field of the Strata II magnet was able to be increased by putting neodymium magnets on it. The programming method was then successfully used in a patient with a jammed Codman Hakim programmable valve. After successful programming using this method, clinical and radiological follow-up of the patient was advised.

Pannus Formation Leads to Valve Malfunction in the Tricuspid Position 19 Years after Triple Valve Replacement.

PubMed

Alskaf, Ebraham; McConkey, Hannah; Laskar, Nabila; Kardos, Attila

2016-06-20

The Medtronic ATS Open Pivot mechanical valve has been successfully used in heart valve surgery for more than two decades. We present the case of a patient who, 19 years following a tricuspid valve replacement with an ATS prosthesis as part of a triple valve operation following infective endocarditis, developed severe tricuspid regurgitation due to pannus formation.

Recurrent pannus formation causing prosthetic aortic valve dysfunction: is excision without valve re-replacement applicable?

PubMed

Darwazah, Ahmad K

2012-06-29

Prosthetic valve dysfunction at aortic position is commonly caused by pannus formation. The exact etiology is not known. It arises from ventricular aspect of the prosthesis encroaching its leaflets causing stenosis or it may remain localized causing left ventricular outflow tract obstruction without affecting valve function.The difference in location entails different approaches in management. Such a pathology requires surgical excision of the pannus with or without valve re-replacement.A recurrent pannus was observed in a female patient who needed repeated surgical intervention to excise a localized pannus without re-replacement of a well functioning prosthetic valve.Management of our case presents several questions, whether recurrence of pannus is caused by sparing the prosthetic valve, is it simply an exaggeration of an inflammatory healing process in certain individuals or is it ideal to re-replace the valve despite a well preserved function.

Analysis of Complex Valve and Feed Systems

NASA Technical Reports Server (NTRS)

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.

High speed exhaust gas recirculation valve

DOEpatents

Fensom, Rod; Kidder, David J.

2005-01-18

In order to minimize pollutants such as Nox, internal combustion engines typically include an exhaust gas recirculation (EGR) valve that can be used to redirect a portion of exhaust gases to an intake conduit, such as an intake manifold, so that the redirected exhaust gases will be recycled. It is desirable to have an EGR valve with fast-acting capabilities, and it is also desirable to have the EGR valve take up as little space as possible. An exhaust gas recirculation valve is provided that includes an exhaust passage tube, a valve element pivotally mounted within the exhaust passage tube, a linear actuator; and a gear train. The gear train includes a rack gear operatively connected to the linear actuator, and at least one rotatable gear meshing with the rack gear and operatively connected to the valve element to cause rotation of the valve element upon actuation of the linear actuator. The apparatus provides a highly compact package having a high-speed valve actuation capability.

A new one-step procedure for pulmonary valve implantation of the melody valve: Simultaneous prestenting and valve implantation.

PubMed

Boudjemline, Younes

2018-01-01

To describe a new modification, the one-step procedure, that allows interventionists to pre-stent and implant a Melody valve simultaneously. Percutaneous pulmonary valve implantation (PPVI) is the standard of care for managing patients with dysfunctional right ventricular outflow tract, and the approach is standardized. Patients undergoing PPVI using the one-step procedure were identified in our database. Procedural data and radiation exposure were compared to those in a matched group of patients who underwent PPVI using the conventional two-step procedure. Between January 2016 and January 2017, PPVI was performed in 27 patients (median age/range, 19.1/10-55 years) using the one-step procedure involving manual crimping of one to three bare metal stents over the Melody valve. The stent and Melody valve were delivered successfully using the Ensemble delivery system. No complications occurred. All patients had excellent hemodynamic results (median/range post-PPVI right ventricular to pulmonary artery gradient, 9/0-20 mmHg). Valve function was excellent. Median procedural and fluoroscopic times were 56 and 10.2 min, respectively, which significantly differed from those of the two-step procedure group. Similarly, the dose area product (DAP), and radiation time were statistically lower in the one-step group than in the two-step group (P < 0.001 for all variables). After a median follow-up of 8 months (range, 3-14.7), no patient underwent reintervention, and no device dysfunction was observed. The one-step procedure is a safe modification that allows interventionists to prestent and implants the Melody valve simultaneously. It significantly reduces procedural and fluoroscopic times, and radiation exposure. © 2017 Wiley Periodicals, Inc.

Olympic and world sport: making transnational society?

PubMed

Giulianotti, Richard; Brownell, Susan

2012-06-01

This paper introduces the special issue of the British Journal of Sociology on the subject of the transnational aspects of Olympic and world sport. The special issue is underpinned by the perspective that because sport provides a space for the forging of transnational connections and global consciousness, it is increasingly significant within contemporary processes of globalization and the making of transnational society. In this article, we examine in turn eight social scientific themes or problems that are prominent within the special issue: globalization, glocalization, neo-liberal ideologies and policies, transnational society, securitization, global civil society, transnational/global public sphere, and fantasy/imagination. We conclude by highlighting five 'circles' of future research inquiry within world sport that should be explored by social scientists. © London School of Economics and Political Science 2012.

Axial computed tomography evaluation of the internal nasal valve correlates with clinical valve narrowing and patient complaint.

PubMed

Moche, Jason A; Cohen, Justin C; Pearlman, Steven J

2013-07-01

The objective of this work was to explore the utility of axial computed tomography (CT) imaging to objectively define a narrow internal nasal valve, and compare those findings with clinical examination and patient complaint. Retrospective review from a single facial plastic surgery center. We reviewed 40 consecutive patients evaluated for either sinusitis or nasal airway obstruction for which a CT scan was obtained at a single radiology institution. Thirty-six complete office records were examined for the presence of clinical internal valve narrowing and complaints of nasal obstruction. In total, 72 internal nasal valves were analyzed using axial plane CT and measurements were compared to clinical findings and presence of airway obstruction. Measured valve areas for clinically normal internal nasal valves averaged 0.47 cm(2) vs 0.28 cm(2) for clinically narrow valves, a decrease of 40.4%. In unobstructed nasal airways the valve area averaged 0.51 cm(2) vs 0.38 cm(2) in obstructed airways, a difference of 25.5%. A radiographically measured valve area of <0.30 cm(2) suggests clinical narrowing with a sensitivity of 71.4%, specificity of 88.9%, positive predictive value of 62.5%, and negative predictive value of 92.3%. Using standard axial CT imaging we describe an objective method of radiographically evaluating the nasal valve, demonstrating strong correlation with physical examination and patient complaint. Additionally, radiographic valve areas can be used to screen for clinically narrow nasal valves with good sensitivity and specificity, providing a novel straightforward method for nasal valve assessment. © 2012 ARS-AAOA, LLC.

Mechanical valve replacement in congenital heart disease.

PubMed

Fiane, A E; Lindberg, H L; Saatvedt, K; Svennevig, J L

1996-05-01

Mechanical valves are the prosthesis of choice in valve replacement in children. However, the problem of somatic growth leading to patient-valve mismatch remains present, and the appropriate anticoagulation regimen remains controversial. We present our experience of valve replacement in a young population over 20 years. Between 1972 and 1992, 48 patients (34 males and 14 females), mean age 11.2 years (range 0.4-27.4 years), underwent mechanical valve replacement at our institution. Aortic valve replacement was performed in 28 patients (58.3%), mitral valve replacement in 13 (27.1%), tricuspid valve replacement in six (12.5%) and pulmonary valve replacement in one patient (2.1%). The prostheses used were: St. Jude Medical (n = 2), Björk-Shiley (n = 14), Medtronic Hall (n = 16), Duromedics (n = 2) and CarboMedics (n = 14). Early mortality was 14.3%, 10.7% for aortic valve replacement and 30.8% for mitral valve replacement. Mean follow up for all patients was 8.3 years (range 0-22 years), with a total of 398 patient-years. Seven patients died during the follow up (17.1%). Survival after 10 years, including operative mortality, was 81% for aortic valve replacement, 33% for mitral valve replacement, 83% for tricuspid valve replacement and 100% for pulmonary valve replacement. All patients were anticoagulated with warfarin. In eight patients (16.7%) an antiplatelet drug (aspirin or dipyridamole) was added. Major events included paravalvular leak in six patients (1.5%/pty), valve thrombosis in five (mitral position in two, tricuspid in three) (1.3%/pty) and endocarditis in one patient (0.3%/pty). Minor thromboembolic events occurred in three patients (0.8%/pty) and minor hemorrhagic events in three (0.8%/pty). No patients developed hemolytic anemia and there was no case of structural failure. In our experience, mechanical prostheses in congenital heart disease were associated with significant morbidity and mortality, however long term survival after aortic valve

Prosthetic Aortic Valve Fixation Study: 48 Replacement Valves Analyzed Using Digital Pressure Mapping.

PubMed

Lee, Candice Y; Wong, Joshua K; Ross, Ronald E; Liu, David C; Khabbaz, Kamal R; Martellaro, Angelo J; Gorea, Heather R; Sauer, Jude S; Knight, Peter A

Prostheses attachment is critical in aortic valve replacement surgery, yet reliable prosthetic security remains a challenge. Accurate techniques to analyze prosthetic fixation pressures may enable the use of fewer sutures while reducing the risk of paravalvular leaks (PVL). Customized digital thin film pressure transducers were sutured between aortic annulus models and 21-mm bioprosthetic valves with 15 × 4-mm, 12 × 4-mm, or 9 × 6-mm-wide pledgeted mattress sutures. Simulating open and minimally invasive access, 4 surgeons, blinded to data acquisition, each secured 12 valves using manual knot-tying (hand-tied [HT] or knot-pusher [KP]) or automated titanium fasteners (TFs). Real-time pressure measurements and times were recorded. Two-dimensional (2D) and 3D pressure maps were generated for all valves. Pressures less than 80 mm Hg were considered at risk for PVL. Pressures under each knot (intrasuture) fell less than 80 mm Hg for 12 of 144 manual knots (5/144 HT, 7/144 KP) versus 0 of 288 TF (P < 0.001). Pressures outside adjacent sutures (extrasuture) were less than 80 mm Hg in 10 of 60 HT, zero of 60 KP, and zero of 120 TF sites for 15 × 4-mm valves; 17 of 48 HT, 25 of 48 KP, and 12 of 96 TF for 12 × 4-mm valves; and 15 of 36 HT, 17 of 36 KP, and 9 and 72 TF for 9 × 6-mm valves; P < 0.001 all manual versus TF. Annular areas with pressures less than 80 mm Hg ranged from 0% of the sewing-ring area (all open TF) to 31% (12 × 4 mm, KP). The average time per manual knot, 46 seconds (HT, 31 seconds; KP, 61 seconds), was greater than TF, 14 seconds (P < 0.005). Reduced operative times and PVL risk would fortify the advantages of surgical aortic valve replacement. This research encourages continued exploration of technical factors in optimizing prosthetic valve security.

Long-Term Survival and Freedom From Reoperation After Placement of a Pulmonary Xenograft Valved Conduit.

PubMed

Alfieris, George M; Swartz, Michael F; Lehoux, Juan; Bove, Edward L

2016-08-01

The optimal choice for pulmonary valve replacement (PVR) remains controversial. This study hypothesized that xenografts used for PVR would result in prolonged long-term survival and freedom from reoperation. Children and adults with congenital heart disease requiring PVR using a xenograft from 1980 to 1985 were reviewed. In all cases, the xenograft valve was either sewn or manufactured into a Dacron conduit, and the conduit was sewn to the pulmonary artery bifurcation. Clinical data were analyzed, and survival and freedom from reoperation were determined using Kaplan-Meier analysis. Twenty-four patients received a xenograft for PVR at 14.6 ± 5.6 years. Conduit size ranged from 21 to 27 mm. Most patients received a Carpentier-Edwards valved conduit (n = 17), followed by a Hancock valved conduit (n = 5) and an Ionescu-Shiley valve sewn into a Dacron graft (n = 2). No perioperative deaths occurred. Reoperation was required mainly for pulmonary stenosis (72.7%), followed by pulmonary insufficiency (18.2%), or both stenosis and insufficiency (9%). Freedom from reoperation was 90%, 56%, 43%, and 14% at 10, 20, 25, and 30 years, respectively. At most recent follow-up the was only death, which was related to severe biventricular failure 25 years after conduit implant. PVR using a xenograft valved conduit results in prolonged freedom from reoperation and excellent long-term survival. These data, which provide long-term follow-up information on xenograft valves after PVR. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

FLUID PRESSURE AND CAM OPERATED VACUUM VALVE

DOEpatents

Batzer, T.H.

1963-11-26

An ultra-high vacuum valve that is bakable, reusable, and capable of being quickly opened and closed is described. A translationally movable valve gate having an annular ridge is adapted to contact an annular soft metal gasket disposed at the valve seat such that the soft metal gasket extends beyond the annular ridge on all sides. The valve gate is closed, by first laterally aligning the valve gate with the valve seat and then bringing the valve gate and valve seat into seating contact by the translational movement of a ramp-like wedging means that engages similar ramp-like stractures at the base of the valve gate to force the valve gate into essentially pressureless contact with the annular soft metal gasket. This gasket is then pressurized from beneath by a fluid thereby effecting a vacuura tight seal between the gasket and the ridge. (AEC)

A Different Mirror: The Position of Immigrant Writers in British Society.

ERIC Educational Resources Information Center

Williams, Bronwyn T.

In teaching international students in Britain and students in the United States in multicultural and multiclass classrooms, a common resistance was found to the consideration of how culture and society shape identity. Even international students from collectivist cultures, who see their identities as inextricable from their communities in their…

Flow metering valve

DOEpatents

Blaedel, K.L.

1983-11-03

An apparatus for metering fluids at high pressures of about 20,000 to 60,000 psi is disclosed. The apparatus includes first and second plates which are positioned adjacent each other to form a valve chamber. The plates are made of materials which have substantially equal elastic properties. One plate has a planar surface area, and the other a recessed surface area defined by periphery and central lips. When the two plates are positioned in adjacent contacting relationship, a valve chamber is formed between the planar surface area and the recessed surface area. Fluid is introduced into the chamber and exits therefrom when a deformation occurs at positions where they no longer form a valve seat. This permits the metering of fluids at high pressures and at slow variable rates. Fluid then exits from the chamber until an applied external force becomes large enough to bring the valve seats back into contact.

Flow metering valve

DOEpatents

Blaedel, Kenneth L.

1985-01-01

An apparatus for metering fluids at high pressures of about 20,000 to 60,000 psi is disclosed. The apparatus includes first and second plates which are positioned adjacent each other to form a valve chamber. The plates are made of materials which have substantially equal elastic properties. One plate has a planar surface area, and the other a recessed surface area defined by periphery and central lips. When the two plates are positioned in adjacent contacting relationship, a valve chamber is formed between the planar surface area and the recessed surface area. Fluid is introduced into the chamber and exits therefrom when a deformation occurs at positions where they no longer form a valve seat. This permits the metering of fluids at high pressures and at slow variable rates. Fluid then exits from the chamber until an applied external force becomes large enough to bring the valve seats back into contact.

How Heart Valves Evolve to Adapt to an Extreme-Pressure System: Morphologic and Biomechanical Properties of Giraffe Heart Valves.

PubMed

Amstrup Funder, Jonas; Christian Danielsen, Carl; Baandrup, Ulrik; Martin Bibby, Bo; Carl Andelius, Ted; Toft Brøndum, Emil; Wang, Tobias; Michael Hasenkam, J

2017-01-01

Heart valves which exist naturally in an extreme-pressure system must have evolved in a way to resist the stresses of high pressure. Giraffes are interesting as they naturally have a blood pressure twice that of humans. Thus, knowledge regarding giraffe heart valves may aid in developing techniques to design improved pressure-resistant biological heart valves. Heart valves from 12 giraffes and 10 calves were explanted and subjected to either biomechanical or morphological examinations. Strips from the heart valves were subjected to cyclic loading tests, followed by failure tests. Thickness measurements and analyses of elastin and collagen content were also made. Valve specimens were stained with hematoxylin and eosin, elastic van Gieson stain, Masson's trichrome and Fraser-Lendrum stain, as well as immunohistochemical reactions for morphological examinations. The aortic valve was shown to be 70% (95% CI 42-103%) stronger in the giraffe than in its bovine counterpart (p <0.001). No significant difference was found between mitral or pulmonary valves. After normalization for collagen, no significant differences were found in strength between species. The giraffe aortic valve was found to be significantly stiffer than the bovine aortic valve (p <0.001), with no significant difference between mitral and pulmonary valves. On a dry weight basis, the aortic (10.9%), pulmonary (4.3%), and mitral valves (9.6%) of giraffes contained significantly more collagen than those of calves. The elastin contents of the pulmonary valves (2.5%) and aortic valves (1.5%) were also higher in giraffes. The greater strength of the giraffe aortic valve is most likely due to a compact collagen construction. Both, collagen and elastin contents were higher in giraffes than in calves, which would make giraffe valves more resistant to the high-pressure forces. However, collagen also stiffens and thickens the valves. The mitral leaflets showed similar (but mostly insignificant) trends in strength

Cavitation guide for control valves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tullis, J.P.

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 sixmore » 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.« less

Recurrent pannus formation causing prosthetic aortic valve dysfunction: Is excision without valve re-replacement applicable?

PubMed Central

2012-01-01

Prosthetic valve dysfunction at aortic position is commonly caused by pannus formation. The exact etiology is not known. It arises from ventricular aspect of the prosthesis encroaching its leaflets causing stenosis or it may remain localized causing left ventricular outflow tract obstruction without affecting valve function. The difference in location entails different approaches in management. Such a pathology requires surgical excision of the pannus with or without valve re-replacement. A recurrent pannus was observed in a female patient who needed repeated surgical intervention to excise a localized pannus without re-replacement of a well functioning prosthetic valve. Management of our case presents several questions, whether recurrence of pannus is caused by sparing the prosthetic valve, is it simply an exaggeration of an inflammatory healing process in certain individuals or is it ideal to re-replace the valve despite a well preserved function. PMID:22747790

Quartz ball valve

NASA Technical Reports Server (NTRS)

Goetz, C.; Ingle, W. M. (Inventor)

1980-01-01

A ball valve particularly suited for use in the handling of highly corrosive fluids is described. It is characterized by a valve housing formed of communicating segments of quartz tubing, a pair of communicating sockets disposed in coaxial alignment with selected segments of tubing for establishing a pair of inlet ports communicating with a common outlet port, a ball formed of quartz material supported for displacement between the sockets and configured to be received alternately thereby, and a valve actuator including a rod attached to the ball for selectively displacing the ball relative to each of the sockets for controlling fluid flow through the inlet ports.

14 CFR 125.137 - Oil valves.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 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, unless...

14 CFR 125.137 - Oil valves.

Code of Federal Regulations, 2010 CFR

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, unless...

14 CFR 125.137 - Oil valves.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 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, unless...

14 CFR 125.137 - Oil valves.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 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, unless...

14 CFR 125.137 - Oil valves.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 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, unless...

Double-reed exhaust valve engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bennett, Charles L.

An engine based on a reciprocating piston engine that extracts work from pressurized working fluid. The engine includes a double reed outlet valve for controlling the flow of low-pressure working fluid out of the engine. The double reed provides a stronger force resisting closure of the outlet valve than the force tending to open the outlet valve. The double reed valve enables engine operation at relatively higher torque and lower efficiency at low speed, with lower torque, but higher efficiency at high speed.

Self-Esteem: A Cross-Cultural Comparison of British-Chinese, White British and Hong Kong Chinese Children.

ERIC Educational Resources Information Center

Chan, Yiu Man

2000-01-01

Evaluates the self-esteem scores of 1303 children, including Chinese children from Britain and Hong Kong and white British children, using the Coopersmith Self-Esteem Inventory. Finds that British Chinese have significantly higher self-esteem than the Hong Kong children, but there is little difference among white British children. (CMK)

Miniature piezo electric vacuum inlet valve

DOEpatents

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 (<1.6 watts), high pulse rate (<2 milliseconds), variable flow inlet valve is utilized for mass spectroscopic applications or other applications where pulsed or continuous flow conditions are needed. The inlet valve also has a very minimal dead volume of less than 0.01 std/cc. The valve can utilize, for example, a 12 Vdc input/750 Vdc, 3 mA output power supply compared to conventional 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.

Transcatheter Heart Valve Selection and Permanent Pacemaker Implantation in Patients With Pre-Existent Right Bundle Branch Block.

PubMed

van Gils, Lennart; Tchetche, Didier; Lhermusier, Thibault; Abawi, Masieh; Dumonteil, Nicolas; Rodriguez Olivares, Ramón; Molina-Martin de Nicolas, Javier; Stella, Pieter R; Carrié, Didier; De Jaegere, Peter P; Van Mieghem, Nicolas M

2017-03-03

Right bundle branch block is an established predictor for new conduction disturbances and need for a permanent pacemaker (PPM) after transcatheter aortic valve replacement. The aim of the study was to evaluate the absolute rates of transcatheter aortic valve replacement related PPM implantations in patients with pre-existent right bundle branch block and categorize for different transcatheter heart valves. We pooled data on 306 transcatheter aortic valve replacement patients from 4 high-volume centers in Europe and selected those with right bundle branch block at baseline without a previously implanted PPM. Logistic regression was used to evaluate whether PPM rate differed among transcatheter heart valves after adjustment for confounders. Mean age was 83±7 years and 63% were male. Median Society of Thoracic Surgeons score was 6.3 (interquartile range, 4.1-10.2). The following transcatheter valve designs were used: Medtronic CoreValve (n=130; Medtronic, Minneapolis, MN); Edwards Sapien XT (ES-XT; n=124) and Edwards Sapien 3 (ES-3; n=32; Edwards Lifesciences, Irvine, CA); and Boston Scientific Lotus (n=20; Boston Scientific Corporation, Marlborough, MA). Overall permanent pacemaker implantation rate post-transcatheter aortic valve replacement was 41%, and per valve design: 75% with Lotus, 46% with CoreValve, 32% with ES-XT, and 34% with ES-3. The indication for PPM implantation was total atrioventricular block in 98% of the cases. Lotus was associated with a higher PPM rate than all other valves. PPM rate did not differ between ES-XT and ES-3. Ventricular paced rhythm at 30-day and 1-year follow-up was present in 81% at 89%, respectively. Right bundle branch block at baseline is associated with a high incidence of PPM implantation for all transcatheter heart valves. PPM rate was highest for Lotus and lowest for ES-XT and ES-3. Pacemaker dependency remained high during follow-up. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by

Noninvasive valve monitor using alternating electromagnetic field

DOEpatents

Eissenberg, David M.; Haynes, Howard D.; Casada, Donald A.

1993-01-01

One or more electrical coils are carefully located on the outside of a valve body. An alternating current passing through the coil(s) results in an alternating electromagnetic field being transmitted into the valve body and valve internals. The electromagnetic field varies in intensity and polarity in the valve. As the position of a valve internal part is changed, the electromagnetic field throughout the valve body and its internals is altered. A passive receiver coil carefully located on the outside of the valve body detects the intensity of the electromagnetic field at that location as an induced electrical voltage in the coil. With the change in position of the valve internal part, there is a corresponding change in the induced voltage as a result of the alteration in the alternating electromagnetic field at that location. Changes in the voltage provide an indication of the position and motion of valve internals.

Noninvasive valve monitor using alternating electromagnetic field

DOEpatents

Eissenberg, D.M.; Haynes, H.D.; Casada, D.A.

1993-03-16

One or more electrical coils are carefully located on the outside of a valve body. An alternating current passing through the coil(s) results in an alternating electromagnetic field being transmitted into the valve body and valve internals. The electromagnetic field varies in intensity and polarity in the valve. As the position of a valve internal part is changed, the electromagnetic field throughout the valve body and its internals is altered. A passive receiver coil carefully located on the outside of the valve body detects the intensity of the electromagnetic field at that location as an induced electrical voltage in the coil. With the change in position of the valve internal part, there is a corresponding change in the induced voltage as a result of the alteration in the alternating electromagnetic field at that location. Changes in the voltage provide an indication of the position and motion of valve internals.

Triple valve surgery: a 25-year experience.

PubMed

Yilmaz, Mustafa; Ozkan, Murat; Böke, Erkmen

2004-09-01

Surgical treatment of rheumatic valvular disease still constitutes a significant number of cardiac operations in developing countries. Despite improvements in myocardial protection and cardiopulmonary bypass techniques, triple valve operations (aortic, mitral and tricuspid valves) are still challenging because of longer duration of cardiopulmonary bypass and higher degree of myocardial decompensation. This study was instituted in order to assess results of triple valve surgery. Between 1977 and 2002, 34 patients underwent triple valve surgery in our clinic by the same surgeon (EB). Eleven patients underwent triple valve replacement (32.4%) and 23 underwent tricuspid valve annuloplasty with aortic and mitral valve replacements (67.6%). There was no significant difference between the two groups of patients who underwent triple valve replacement and aortic and mitral valve replacement with tricuspid valve annuloplasty. There were 4 hospital deaths (11.8%) occurring within 30 days. The duration of follow-up for 30 survivors ranged from 6 to 202 months (mean 97 months). The actuarial survival rates were 85%, 72%, and 48% at 5, 10, and 15 years respectively. Actuarial freedom from reoperation rates at 5, 10, and 15 years was 86.3%, 71.9%, and 51.2%, respectively. Freedom from cerebral thromboembolism and anticoagulation-related hemorrhage rates, expressed in actuarial terms was 75.9% and 62.9% at 5 and 10 years. Major cerebral complications occurred in 10 of the 30 patients. We prefer replacing, if repairing is not possible, the tricuspid valve, with a bileaflet mechanical prosthesis in a patient with valve replacement of the left heart who will be anticoagulated in order to avoid unfavorable properties of bioprosthesis like degeneration and of old generation mechanical prosthesis like thrombosis and poor hemodynamic function. In recent years, results of triple valve surgery either with tricuspid valve conservation or valve replacement in suitable cases have become

Acute aortic regurgitation secondary to disk embolization of a Björk-Shiley prosthetic aortic valve.

PubMed

Grande, Robert D; Katz, William E

2011-03-01

Having passed the 30th anniversary of the first implantation of a Björk-Shiley convexo-concave tilting mechanical valve, recognition of the life-threatening complication of strut fracture is not widespread. The authors report the case of a 48-year-old man with acute-onset chest pain and dyspnea found to have strut fracture and disk embolization of a 26-year-old Björk-Shiley prosthetic aortic valve. The value of echocardiography in the diagnosis of this condition is discussed. Copyright © 2010 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.

Transcatheter Pulmonary Valve Replacement by Hybrid Approach Using a Novel Polymeric Prosthetic Heart Valve: Proof of Concept in Sheep

PubMed Central

Xu, Tong-yi; Zhang, Zhi-gang; Li, Xin; Han, Lin; Xu, Zhi-yun

2014-01-01

Background Since 2000, transcatheter pulmonary valve replacement has steadily advanced. However, the available prosthetic valves are restricted to bioprosthesis which have defects like poor durability. Polymeric heart valve is thought as a promising alternative to bioprosthesis. In this study, we introduced a novel polymeric transcatheter pulmonary valve and evaluated its feasibility and safety in sheep by a hybrid approach. Methods We designed a novel polymeric trileaflet transcatheter pulmonary valve with a balloon-expandable stent, and the valve leaflets were made of 0.1-mm expanded polytetrafluoroethylene (ePTFE) coated with phosphorylcholine. We chose glutaraldehyde-treated bovine pericardium valves as control. Pulmonary valve stents were implanted in situ by a hybrid transapical approach in 10 healthy sheep (8 for polymeric valve and 2 for bovine pericardium valve), weighing an average of 22.5±2.0 kg. Angiography and cardiac catheter examination were performed after implantation to assess immediate valvular functionality. After 4-week follow-up, angiography, echocardiography, computed tomography, and cardiac catheter examination were used to assess early valvular function. One randomly selected sheep with polymeric valve was euthanized and the explanted valved stent was analyzed macroscopically and microscopically. Findings Implantation was successful in 9 sheep. Angiography at implantation showed all 9 prosthetic valves demonstrated orthotopic position and normal functionality. All 9 sheep survived at 4-week follow-up. Four-week follow-up revealed no evidence of valve stent dislocation or deformation and normal valvular and cardiac functionality. The cardiac catheter examination showed the peak-peak transvalvular pressure gradient of the polymeric valves was 11.9±5.0 mmHg, while that of two bovine pericardium valves were 11 and 17 mmHg. Gross morphology demonstrated good opening and closure characteristics. No thrombus or calcification was seen

Tricuspid regurgitation and right ventricular function after mitral valve surgery with or without concomitant tricuspid valve procedure

PubMed Central

Desai, Ravi R.; Vargas Abello, Lina Maria; Klein, Allan L.; Marwick, Thomas H.; Krasuski, Richard A.; Ye, Ying; Nowicki, Edward R.; Rajeswaran, Jeevanantham; Blackstone, Eugene H.; Pettersson, Gösta B.

2014-01-01

Objectives To study the effect of mitral valve repair with or without concomitant tricuspid valve repair on functional tricuspid regurgitation and right ventricular function. Methods From 2001 to 2007, 1833 patients with degenerative mitral valve disease, a structurally normal tricuspid valve, and no coronary artery disease underwent mitral valve repair, and 67 underwent concomitant tricuspid valve repair. Right ventricular function (myocardial performance index and tricuspid annular plane systolic excursion) was measured before and after surgery using transthoracic echocardiography for randomly selected patients with tricuspid regurgitation grade 0, 1+, and 2+(100 patients for each grade) and 93 with grade 3+/4+, 393 patients in total. Results In patients with mild (<3+) preoperative tricuspid regurgitation, mitral valve repair alone was associated with reduced tricuspid regurgitation and mild worsening of right ventricular function. Tricuspid regurgitation of 2+or greater developed in fewer than 20%, and right ventricular function had improved, but not to preoperative levels, at 3 years. In patients with severe (3+/4+) preoperative tricuspid regurgitation, mitral valve repair alone reduced tricuspid regurgitation and improved right ventricular function; however, tricuspid regurgitation of 2+ or greater returned and right ventricular function worsened toward preoperative levels within 3 years. Concomitant tricuspid valve repair effectively eliminated severe tricuspid regurgitation and improved right ventricular function. Also, over time, tricuspid regurgitation did not return and right ventricular function continued to improve to levels comparable to that of patients with lower grades of preoperative tricuspid regurgitation. Conclusions In patients with mitral valve disease and severe tricuspid regurgitation, mitral valve repair alone was associated with improved tricuspid regurgitation and right ventricular function. However, the improvements were incomplete and

[Transcatheter aortic valve replacement].

PubMed

Sawa, Yoshiki

2014-07-01

While transcatheter aortic valve replacement( TAVR) has spread rapidly all over the world for highrisk patients with severe aortic stenosis (AS), SAPIEN XT was approved in Japan in October 2013. Since that, approximately 400 TAVR cases were performed in Japan. In our institute, we have performed 164 cases since first case in Japan in 2009 and have achieved satisfactory early results(30-day mortality:1.2%). At the same time, however, simultaneously various TAVR-related complications including a paravalvular leak, stroke, vascular complications, and coronary obstruction were observed. A reduction in the incidence and severity of these complications had led technical improvements in various new devices(2nd generation TAVR device such as the SAPIEN 3, ACURATE, and JenaValve) and in implantation techniques including repositioning/recapturing features, paravalvular sealing technologies, and prevention of coronary obstruction. Furthermore, there is also increasing experience with special indications for TAVR such as pure aortic valve insufficiency or valve-in-valve techniques. Currently, an increasing number of publications of midterm results demonstrate good prosthetic valve function and durability, with good quality of life and low morbidity after TAVR. There are also some randomized trials such as PARTNER 2 or SURTAVI to investigate potential benefits of TAVR for intermediate-risk patients. These improvements in the TAVR devices promises the expansion of TAVR towards the treatment of lower-risk patients in the near future.

Improved solenoid valve design

NASA Technical Reports Server (NTRS)

Evans, J.

1969-01-01

Modified solenoid valve reduces valve seat loading by eliminating off-center operation of the armature, reducing the poppet size and spring-cushioning its impact, and reducing armature impact with a poppet guide stop.

Proceedings of the Third NRC/ASME Symposium on Valve and Pump Testing. Session 1A--Session 2C: Volume 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1994-07-01

The 1994 Symposium on Valve and Pump Testing, jointly sponsored by the Board of Nuclear Codes and Standards of the American Society of Mechanical Engineers and by the Nuclear Regulatory Commission, provides a forum for the discussion of current programs and methods for inservice testing and motor-operated valve testing at nuclear power plants. The symposium also provides an opportunity to discuss the need to improve that testing in order to help ensure the reliable performance of pumps and valves. The participation of industry representatives, regulators, and consultants results in the discussion of a broad spectrum of ideas and perspectives regardingmore » the improvement of inservice testing of pumps and valves at nuclear power plants. This document, Volume 1, covers sessions 1A through session 2C. The individual papers have been cataloged separately.« less

Miniature piezo electric vacuum inlet valve

DOEpatents

Keville, R.F.; Dietrich, D.D.

1998-03-24

A miniature piezo electric vacuum inlet valve having a fast pulse rate and is battery operated with variable flow capability is disclosed. The low power (<1.6 watts), high pulse rate (<2 milliseconds), variable flow inlet valve is utilized for mass spectroscopic applications or other applications where pulsed or continuous flow conditions are needed. The inlet valve also has a very minimal dead volume of less than 0.01 std/cc. The valve can utilize, for example, a 12 Vdc input/750 Vdc, 3 mA output power supply compared to conventional 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. 6 figs.

Latching Solenoid-Operated Ball Valve

NASA Technical Reports Server (NTRS)

Brudnicki, Myron

1994-01-01

Proposed solenoid-operated ball valve latches in open or closed position until energized to change position. Electrical energy consumed only during opening or closing motion. Valve ball contains central channel through which fluid could flow. Made of highly magnetically permeable steel. When appropriate coil(s) energized by brief pulse (or pulses) of electrical current at appropriate polarity, ball rotates clockwise until permanent magnets come to rest against hard stops in housing, and inlet and outlet ports aligned with central channel so fluid flows through valve. Magnets adhere to stops by magnetic attraction, latching valve in open position. To close valve, appropriate coil(s) energized by pulse (or pulses) of appropriate polarity to generate magnetic forces rotating ball counterclockwise until magnets make contact with hard stops, and inlet and outlet ports sealed.

A Parylene MEMS Electrothermal Valve

PubMed Central

Li, Po-Ying; Givrad, Tina K.; Holschneider, Daniel P.; Maarek, Jean-Michel I.; Meng, Ellis

2011-01-01

The first microelectromechanical-system normally closed electrothermal valve constructed using Parylene C is described, which enables both low power (in milliwatts) and rapid operation (in milliseconds). This low-power valve is well suited for applications in wirelessly controlled implantable drug-delivery systems. The simple design was analyzed using both theory and modeling and then characterized in benchtop experiments. Operation in air (constant current) and water (current ramping) was demonstrated. Valve-opening powers of 22 mW in air and 33 mW in water were obtained. Following integration of the valve with catheters, our valve was applied in a wirelessly operated microbolus infusion pump, and the in vivo functionality for the appropriateness of use of this pump for future brain mapping applications in small animals was demonstrated. PMID:21350679

Effectiveness of rivaroxaban for thromboprophylaxis of prosthetic heart valves in a porcine heterotopic valve model.

PubMed

Greiten, Lawrence E; McKellar, Stephen H; Rysavy, Joseph; Schaff, Hartzell V

2014-05-01

Warfarin is used to reduce the risk of stroke and thromboembolic complications in patients with mechanical heart valves. Yet, despite frequent blood testing, its poor pharmacokinetic and pharmacodynamic profiles often result in variable therapeutic levels. Rivaroxaban is a direct competitive factor Xa inhibitor that is taken orally. It inhibits the active site of factor Xa without the need for the cofactor antithrombin, and thus, its mechanism of action is differentiated from that of the fractionated heparins and indirect factor Xa inhibitors. No in vivo data exist regarding the effectiveness of rivaroxaban in preventing thromboembolic complications of mechanical heart valves. We tested the hypothesis that rivaroxaban is as effective as enoxaparin for thromboprophylaxis of mechanical valves that use a previously described heterotopic aortic valve porcine model. A modified bileaflet mechanical valved conduit that bypassed the native, ligated descending thoracic aorta was implanted into 30 swine. Postoperatively, the animals were randomly assigned to groups receiving no anticoagulation (n = 10), enoxaparin at 2 mg/kg subcutaneously twice daily (n = 10) or rivaroxaban at 2 mg/kg orally twice daily (n = 10). The amount of valve thrombus was measured on post-implantation day 30 as the primary end point. Quantitative evaluation of radiolabelled platelet deposition on the valve prostheses was done and embolic and haemorrhagic events were measured as secondary end points. Animals with no anticoagulation had a thrombus mean of 759.9 mg compared with 716.8 mg with enoxaparin treatment and 209.6 mg with rivaroxaban treatment (P = 0.05 for enoxaparin vs rivaroxaban). Similarly, the mean number of platelets deposited on the valve prosthesis was lower in the rivaroxaban group (6.13 × 10(9)) than in the enoxaparin group (3.03 × 10(10)) (P = 0.03). In this study, rivaroxaban was more effective than enoxaparin for short-term thromboprophylaxis of mechanical valve prosthetics in

Heart Valve Biomechanics and Underlying Mechanobiology

PubMed Central

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

TUBE SHEARING VALVE

DOEpatents

Wilner, L.B.

1960-05-24

Explosive operated valves can be used to join two or more containers in fluid flow relationship, one such container being a sealed reservoir. The valve is most simply disposed by mounting it on the reservoir so thst a tube extends from the interior of the reservoir through the valve body, terminating at the bottom of the bore in a closed end; other containers may be similarly connected or may be open connected, as desired. The piston of the valve has a cutting edge at its lower end which shears off the closed tube ends and a recess above the cutting edge to provide a flow channel. Intermixing of the fluid being transferred with the explosion gases is prevented by a copper ring at the top of the piston which is force fitted into the bore at the beginning of the stroke. Although designed to avoid backing up of the piston at pressures up to 10,000 psi in the transferred fluid, proper operation is independent of piston position, once the tube ends were sheared.

Problem: Heart Valve Regurgitation

MedlinePlus

... should be completely closed For example: Watch an animation of mitral valve regurgitation A leaking mitral valve ... Not Alone Popular Articles 1 Understanding Blood Pressure Readings 2 Sodium and Salt 3 Heart Attack Symptoms ...

Problem: Mitral Valve Regurgitation

MedlinePlus

... each time the left ventricle contracts. Watch an animation of mitral valve regurgitation A leaking mitral valve ... Not Alone Popular Articles 1 Understanding Blood Pressure Readings 2 Sodium and Salt 3 Heart Attack Symptoms ...

Mitral valve surgery - open

MedlinePlus

... place. There are two types of mitral valves: Mechanical, made of man-made (synthetic) materials, such as ... Mechanical heart valves last a lifetime. However, blood clots may develop on them. This can cause them ...

Are anticoagulant independent mechanical valves within reach-fast prototype fabrication and in vitro testing of innovative bi-leaflet valve models.

PubMed

Scotten, Lawrence N; Siegel, Rolland

2015-08-01

Exploration for causes of prosthetic valve thrombogenicity has frequently focused on forward or post-closure flow detail. In prior laboratory studies, we uncovered high amplitude flow velocities of short duration close to valve closure implying potential for substantial shear stress with subsequent initiation of blood coagulation pathways. This may be relevant to widely accepted clinical disparity between mechanical and tissue valves vis-à-vis thrombogenicity. With a series of prototype bi-leaflet mechanical valves, we attempt reduction of closure related velocities with the objective of identifying a prototype valve with thrombogenic potential similar to our tissue valve control. This iterative design approach may find application in preclinical assessment of valves for anticoagulation independence. Tested valves included: prototype mechanical bi-leaflet BVs (n=56), controls (n=2) and patented early prototype mechanicals (n=2) from other investigators. Pulsatile and quasi-steady flow systems were used for testing. Projected dynamic valve area (PDVA) was measured using previously described novel technology. Flow velocity over the open and closing periods was determined by volumetric flow rate/PDVA. For the closed valve interval, use was made of data obtained from quasi-steady back pressure/flow tests. Performance was ranked by a proposed thrombogenicity potential index (TPI) relative to tissue and mechanical control valves. Optimization of the prototype valve designs lead to a 3-D printed model (BV3D). For the mitral/aortic site, BV3D has lower TPI (1.10/1.47) relative to the control mechanical valve (3.44/3.93) and similar to the control tissue valve (ideal TPI ≤1.0). Using unique technology, rapid prototyping and thrombogenicity ranking, optimization of experimental valves for reduced thrombogenic potential was expedited and simplified. Innovative mechanical valve configurations were identified that merit consideration for further development which may bring

Are anticoagulant independent mechanical valves within reach—fast prototype fabrication and in vitro testing of innovative bi-leaflet valve models

PubMed Central

Siegel, Rolland

2015-01-01

Background Exploration for causes of prosthetic valve thrombogenicity has frequently focused on forward or post-closure flow detail. In prior laboratory studies, we uncovered high amplitude flow velocities of short duration close to valve closure implying potential for substantial shear stress with subsequent initiation of blood coagulation pathways. This may be relevant to widely accepted clinical disparity between mechanical and tissue valves vis-à-vis thrombogenicity. With a series of prototype bi-leaflet mechanical valves, we attempt reduction of closure related velocities with the objective of identifying a prototype valve with thrombogenic potential similar to our tissue valve control. This iterative design approach may find application in preclinical assessment of valves for anticoagulation independence. Methods Tested valves included: prototype mechanical bi-leaflet BVs (n=56), controls (n=2) and patented early prototype mechanicals (n=2) from other investigators. Pulsatile and quasi-steady flow systems were used for testing. Projected dynamic valve area (PDVA) was measured using previously described novel technology. Flow velocity over the open and closing periods was determined by volumetric flow rate/PDVA. For the closed valve interval, use was made of data obtained from quasi-steady back pressure/flow tests. Performance was ranked by a proposed thrombogenicity potential index (TPI) relative to tissue and mechanical control valves. Results Optimization of the prototype valve designs lead to a 3-D printed model (BV3D). For the mitral/aortic site, BV3D has lower TPI (1.10/1.47) relative to the control mechanical valve (3.44/3.93) and similar to the control tissue valve (ideal TPI ≤1.0). Conclusions Using unique technology, rapid prototyping and thrombogenicity ranking, optimization of experimental valves for reduced thrombogenic potential was expedited and simplified. Innovative mechanical valve configurations were identified that merit consideration

Torque-actuated valves for microfluidics.

PubMed

Weibel, Douglas B; Kruithof, Maarten; Potenta, Scott; Sia, Samuel K; Lee, Andrew; Whitesides, George M

2005-08-01

This paper describes torque-actuated valves for controlling the flow of fluids in microfluidic channels. The valves consist of small machine screws (> or =500 microm) embedded in a layer of polyurethane cast above microfluidic channels fabricated in poly(dimethylsiloxane) (PDMS). The polyurethane is cured photochemically with the screws in place; on curing, it bonds to the surrounding layer of PDMS and forms a stiff layer that retains an impression of the threads of the screws. The valves were separated from the ceiling of microfluidic channels by a layer of PDMS and were integrated into channels using a simple procedure compatible with soft lithography and rapid prototyping. Turning the screws actuated the valves by collapsing the PDMS layer between the valve and channel, controlling the flow of fluids in the underlying channels. These valves have the useful characteristic that they do not require power to retain their setting (on/off). They also allow settings between "on" and "off" and can be integrated into portable, disposable microfluidic devices for carrying out sandwich immunoassays.

Proof-of-Concept Evaluation of the SailValve Self-Expanding Deep Venous Valve System in a Porcine Model.

PubMed

Boersma, Doeke; Vink, Aryan; Moll, Frans L; de Borst, Gert J

2017-06-01

To evaluate the SailValve, a new self-expanding deep venous valve concept based on a single polytetrafluoroethylene cusp floating up and down in the bloodstream like a sail, acting as a flow regulator and allowing minimal reflux to reduce thrombogenicity. Both iliac veins of 5 pigs were implanted with SailValve devices; the first animal was an acute pilot experiment to show the feasibility of accurately positioning the SailValve via a femoral access. The other 4 animals were followed for 2 weeks (n=2) or 4 weeks (n=2) under a chronic implantation protocol. Patency and valve function were evaluated directly in all animals using ascending and descending phlebography after device placement and at termination in the chronic implant animals. For reasons of clinical relevance, a regimen of clopidogrel and calcium carbasalate was administered. Histological analysis was performed according to a predefined protocol by an independent pathologist. Deployment was technically feasible in all 10 iliac veins, and all were patent directly after placement. No perioperative or postoperative complications occurred. Ascending phlebograms in the follow-up animals confirmed the patency of all valves after 2 or 4 weeks. Descending phlebograms showed full function in 5 of 8 valves. Limited reflux was seen in 1 valve (4-week group), and the function in the remaining 2 valves (2-week group) was insufficient because of malpositioning. No macroscopic thrombosis was noted on histology. Histology in the follow-up groups revealed a progressive inflammatory reaction to the valves. This animal study shows the potential of the SailValve concept with sufficient valve function after adequate positioning and no (thrombogenic) occlusions after short-term follow-up. Future research is essential to optimize valve material and long-term patency.

Valve-spring Surge

NASA Technical Reports Server (NTRS)

Marti, Willy

1937-01-01

Test equipment is described that includes a system of three quartz indicators whereby three different pressures could be synchronized and simultaneously recorded on a single oscillogram. This equipment was used to test the reliction of waves at ends of valve spring, the dynamical stress of the valve spring for a single lift of the valve, and measurement of the curve of the cam tested. Other tests included simultaneous recording of the stress at both ends of the spring, spring oscillation during a single lift as a function of speed, computation of amplitude of oscillation for a single lift by harmonic analysis, effect of cam profile, the setting up of resonance, and forced spring oscillation with damping.

Mitral valve disease—morphology and mechanisms

PubMed Central

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

THERMALLY OPERATED VAPOR VALVE

DOEpatents

Dorward, J.G. Jr.

1959-02-10

A valve is presented for use in a calutron to supply and control the vapor to be ionized. The invention provides a means readily operable from the exterior of the vacuum tank of the apparatuss without mechanical transmission of forces for the quick and accurate control of the ionizing arc by a corresponding control of gas flow theretos thereby producing an effective way of carefully regulating the operation of the calutron. The invention consists essentially of a tube member extending into the charge bottle of a calutron devices having a poppet type valve closing the lower end of the tube. An electrical heating means is provided in the valve stem to thermally vary the length of the stem to regulate the valve opening to control the flow of material from the charge bottle.

46 CFR 52.01-120 - Safety valves and safety relief valves (modifies PG-67 through PG-73).

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Safety valves and safety relief valves (modifies PG-67 through PG-73). 52.01-120 Section 52.01-120 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-120 Safety valves and safety relief valves (modifies PG-67 through PG-73). (a)...

46 CFR 52.01-120 - Safety valves and safety relief valves (modifies PG-67 through PG-73).

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Safety valves and safety relief valves (modifies PG-67 through PG-73). 52.01-120 Section 52.01-120 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-120 Safety valves and safety relief valves (modifies PG-67 through PG-73). (a)...

46 CFR 52.01-120 - Safety valves and safety relief valves (modifies PG-67 through PG-73).

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Safety valves and safety relief valves (modifies PG-67 through PG-73). 52.01-120 Section 52.01-120 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-120 Safety valves and safety relief valves (modifies PG-67 through PG-73). (a)...

46 CFR 52.01-120 - Safety valves and safety relief valves (modifies PG-67 through PG-73).

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Safety valves and safety relief valves (modifies PG-67 through PG-73). 52.01-120 Section 52.01-120 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-120 Safety valves and safety relief valves (modifies PG-67 through PG-73). (a)...

46 CFR 52.01-120 - Safety valves and safety relief valves (modifies PG-67 through PG-73).

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Safety valves and safety relief valves (modifies PG-67 through PG-73). 52.01-120 Section 52.01-120 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-120 Safety valves and safety relief valves (modifies PG-67 through PG-73). (a)...

Use of a Valved-Conduit for Exclusion of the Infected Portion in the Prosthetic Pulmonary Valve Endocarditis

PubMed Central

Jung, Joonho; Lee, Cheol Joo; Lim, Sang-Hyun; Choi, Ho; Park, Soo-Jin

2013-01-01

A 51-year-old male was admitted to the hospital with complaints of fever and hemoptysis. After evaluation of the fever focus, he was diagnosed with pulmonary valve infective endocarditis. Thus pulmonary valve replacement and antibiotics therapy were performed and discharged. He was brought to the emergency unit presenting with a high fever (>39℃) and general weakness 6 months after the initial operation. The echocardiography revealed prosthetic pulmonary valve endocarditis. Therefore, redo-pulmonary valve replacement using valved conduit was performed in the Rastelli fashion because of the risk of pulmonary arterial wall injury and recurrent endocarditis from the remnant inflammatory tissue. We report here on the successful surgical treatment of prosthetic pulmonary valve endocarditis with an alternative surgical method. PMID:23772409

Dual-latching solenoid-actuated valve assembly

NASA Technical Reports Server (NTRS)

Brudnicki, Myron J. (Inventor); Yang, Jeff (Inventor)

1994-01-01

A tube-type shutoff valve is electrically positioned to its open or closed position by a concentric electromagnetic solenoid. The valve is dual latching in that the armature of the solenoid maintains the sliding tube of the valve in an open or closed position by means of permanent magnets which are effective when current is not supplied to the solenoid. The valve may also be actuated manually.

Valve assembly having remotely replaceable bearings

DOEpatents

Johnson, Evan R.; Tanner, David E.

1980-01-01

A valve assembly having remotely replaceable bearings is disclosed wherein a valve disc is supported within a flow duct for rotation about a pair of axially aligned bearings, one of which is carried by a spindle received within a diametral bore in the valve disc, and the other of which is carried by a bearing support block releasably mounted on the duct circumferentially of an annular collar on the valve disc coaxial with its diametrical bore. The spindle and bearing support block are adapted for remote removal to facilitate servicing or replacement of the valve disc support bearings.

Incidence, Timing, and Predictors of Valve Hemodynamic Deterioration After Transcatheter Aortic Valve Replacement: Multicenter Registry.

PubMed

Del Trigo, Maria; Muñoz-Garcia, Antonio J; Wijeysundera, Harindra C; Nombela-Franco, Luis; Cheema, Asim N; Gutierrez, Enrique; Serra, Vicenç; Kefer, Joelle; Amat-Santos, Ignacio J; Benitez, Luis M; Mewa, Jumana; Jiménez-Quevedo, Pilar; Alnasser, Sami; Garcia Del Blanco, Bruno; Dager, Antonio; Abdul-Jawad Altisent, Omar; Puri, Rishi; Campelo-Parada, Francisco; Dahou, Abdellaziz; Paradis, Jean-Michel; Dumont, Eric; Pibarot, Philippe; Rodés-Cabau, Josep

2016-02-16

Scarce data exist on the incidence of and factors associated with valve hemodynamic deterioration (VHD) after transcatheter aortic valve replacement (TAVR). This study sought to determine the incidence, timing, and predictors of VHD in a large cohort of patients undergoing TAVR. This multicenter registry included 1,521 patients (48% male; 80 ± 7 years of age) who underwent TAVR. Mean echocardiographic follow-up was 20 ± 13 months (minimum: 6 months). Echocardiographic examinations were performed at discharge, at 6 to 12 months, and yearly thereafter. Annualized changes in mean gradient (mm Hg/year) were calculated by dividing the difference between the mean gradient at last follow-up and the gradient at discharge by the time between examinations. VHD was defined as a ≥10 mm Hg increase in transprosthetic mean gradient during follow-up compared with discharge assessment. The overall mean annualized rate of transprosthetic gradient progression during follow-up was 0.30 ± 4.99 mm Hg/year. A total of 68 patients met criteria of VHD (incidence: 4.5% during follow-up). The absence of anticoagulation therapy at hospital discharge (p = 0.002), a valve-in-valve (TAVR in a surgical valve) procedure (p = 0.032), the use of a 23-mm valve (p = 0.016), and a greater body mass index (p = 0.001) were independent predictors of VHD. There was a mild but significant increase in transvalvular gradients over time after TAVR. The lack of anticoagulation therapy, a valve-in-valve procedure, a greater body mass index, and the use of a 23-mm transcatheter valve were associated with higher rates of VHD post-TAVR. Further prospective studies are required to determine whether a specific antithrombotic therapy post-TAVR may reduce the risk of VHD. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Innovative Stemless Valve Eliminates Emissions

NASA Technical Reports Server (NTRS)

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.

Fluid check valve has fail-safe feature

NASA Technical Reports Server (NTRS)

Gaul, L. C.

1965-01-01

Check valve ensures unidirectional fluid flow and, in case of failure, vents the downstream fluid to the atmosphere and gives a positive indication of malfunction. This dual valve consists of a master check valve and a fail-safe valve.

Microfluidic Valves Made From Polymerized Polyethylene Glycol Diacrylate

PubMed Central

Rogers, Chad I.; Oxborrow, Joseph B.; Anderson, Ryan R.; Tsai, Long-Fang; Nordin, Gregory P.; Woolley, Adam T.

2013-01-01

Pneumatically actuated, non-elastomeric membrane valves fabricated from polymerized polyethylene glycol diacrylate (poly-PEGDA) have been characterized for temporal response, valve closure, and long-term durability. A ~100 ms valve opening time and a ~20 ms closure time offer valve operation as fast as 8 Hz with potential for further improvement. Comparison of circular and rectangular valve geometries indicates that the surface area for membrane interaction in the valve region is important for valve performance. After initial fabrication, the fluid pressure required to open a closed circular valve is ~50 kPa higher than the control pressure holding the valve closed. However, after ~1000 actuations to reconfigure polymer chains and increase elasticity in the membrane, the fluid pressure required to open a valve becomes the same as the control pressure holding the valve closed. After these initial conditioning actuations, poly-PEGDA valves show considerable robustness with no change in effective operation after 115,000 actuations. Such valves constructed from non-adsorptive poly-PEGDA could also find use as pumps, for application in small volume assays interfaced with biosensors or impedance detection, for example. PMID:24357897

Krox20 defines a subpopulation of cardiac neural crest cells contributing to arterial valves and bicuspid aortic valve.

PubMed

Odelin, Gaëlle; Faure, Emilie; Coulpier, Fanny; Di Bonito, Maria; Bajolle, Fanny; Studer, Michèle; Avierinos, Jean-François; Charnay, Patrick; Topilko, Piotr; Zaffran, Stéphane

2018-01-03

Although cardiac neural crest cells are required at early stages of arterial valve development, their contribution during valvular leaflet maturation remains poorly understood. Here, we show in mouse that neural crest cells from pre-otic and post-otic regions make distinct contributions to the arterial valve leaflets. Genetic fate-mapping analysis of Krox20-expressing neural crest cells shows a large contribution to the borders and the interleaflet triangles of the arterial valves. Loss of Krox20 function results in hyperplastic aortic valve and partially penetrant bicuspid aortic valve formation. Similar defects are observed in neural crest Krox20 -deficient embryos. Genetic lineage tracing in Krox20 -/- mutant mice shows that endothelial-derived cells are normal, whereas neural crest-derived cells are abnormally increased in number and misplaced in the valve leaflets. In contrast, genetic ablation of Krox20 -expressing cells is not sufficient to cause an aortic valve defect, suggesting that adjacent cells can compensate this depletion. Our findings demonstrate a crucial role for Krox20 in arterial valve development and reveal that an excess of neural crest cells may be associated with bicuspid aortic valve. © 2018. Published by The Company of Biologists Ltd.

46 CFR 108.444 - Lockout valves.

Code of Federal Regulations, 2013 CFR

2013-10-01

... dioxide to discharge in the event of equipment failure during maintenance. (c) The lockout valve design or... extinguishing system, when the valve must be locked in the closed position. (f) Lockout valves added to existing...

Missed aortic valve endocarditis resulting in complete atrioventricular block and redo mechanical valve replacement.

PubMed

Harky, Amer; Garner, Megan; Popa, Miruna; Shipolini, Alex

2017-08-03

Infective endocarditis is a rare disease associated with high morbidity and mortality. As a result, early diagnosis and prompt antibiotic treatment with or without surgical intervention is crucial in the management of such condition.We report a case of missed infective endocarditis of the aortic valve. The patient underwent mechanical aortic valve replacement, with the native valve being sent for histopathological examination. On re-admission 16 months later, he presented with syncope, shortness of breathing and complete heart block. On review of the histopathology of native aortic valve, endocarditis was identified which had not been acted on. The patient underwent redo aortic valve replacement for severe aortic regurgitation.We highlight the importance of following up histopathological results as well as the need for multidisciplinary treatment of endocarditis with a combination of surgical and antibiotic therapy. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Premeasured Chordal Loops for Mitral Valve Repair.

PubMed

Gillinov, Marc; Quinn, Reed; Kerendi, Faraz; Gaudiani, Vince; Shemin, Richard; Barnhart, Glenn; Raines, Edward; Gerdisch, Marc W; Banbury, Michael

2016-09-01

Premeasured expanded polytetrafluoroethylene chordal loops with integrated sutures for attachment to the papillary muscle and leaflet edges facilitate correction of mitral valve prolapse. Configured as a group of 3 loops (length range 12 to 24 mm), the loops are attached to a pledget that is passed through the papillary muscle and tied. Each of the loops has 2 sutures with attached needles; these needles are passed through the free edge of the leaflet and then the sutures are tied to each other, securing the chordal loop to the leaflet. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

State and Church in British Honduran Education, 1931-39: A British Colonial Perspective.

ERIC Educational Resources Information Center

Hitchen, Peter

2000-01-01

Offers an analysis of church and state influences on the development of education in British Honduras (now Belize). Focuses on the British neglect of education in the colony; the emergence of tensions between the church and state, exploring issues related to Roman Catholic and Protestant rivalry; and church-state issues. (CMK)

Minimally invasive mitral valve surgery is associated with equivalent cost and shorter hospital stay when compared with traditional sternotomy.

PubMed

Atluri, Pavan; Stetson, Robert L; Hung, George; Gaffey, Ann C; Szeto, Wilson Y; Acker, Michael A; Hargrove, W Clark

2016-02-01

Mitral valve surgery is increasingly performed through minimally invasive approaches. There are limited data regarding the cost of minimally invasive mitral valve surgery. Moreover, there are no data on the specific costs associated with mitral valve surgery. We undertook this study to compare the costs (total and subcomponent) of minimally invasive mitral valve surgery relative to traditional sternotomy. All isolated mitral valve repairs performed in our health system from March 2012 through September 2013 were analyzed. To ensure like sets of patients, only those patients who underwent isolated mitral valve repairs with preoperative Society of Thoracic Surgeons scores of less than 4 were included in this study. A total of 159 patients were identified (sternotomy, 68; mini, 91). Total incurred direct cost was obtained from hospital financial records. Analysis demonstrated no difference in total cost (operative and postoperative) of mitral valve repair between mini and sternotomy ($25,515 ± $7598 vs $26,049 ± $11,737; P = .74). Operative costs were higher for the mini cohort, whereas postoperative costs were significantly lower. Postoperative intensive care unit and total hospital stays were both significantly shorter for the mini cohort. There were no differences in postoperative complications or survival between groups. Minimally invasive mitral valve surgery can be performed with overall equivalent cost and shorter hospital stay relative to traditional sternotomy. There is greater operative cost associated with minimally invasive mitral valve surgery that is offset by shorter intensive care unit and hospital stays. Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

[Tricuspid valve insufficiency: what should be done?].

PubMed

von Segesser, L K; Stauffer, J C; Delabays, A; Chassot, P G

1998-12-01

Tricuspid regurgitation is relatively common. Due to the progress made in echocardiography, its diagnosis is in general made readily and in reliable fashion. Basically one has to distinguish between functional tricuspid valve regurgitation due to volume and/or pressure overload of the right ventricle with intact valve structures versus tricuspid valve regurgitation due to pathologic valve structures. The clear identification of the regurgitation mechanism is of prime importance for the treatment. Functional tricuspid valve regurgitation can often be improved by medical treatment of heart failure, and eventually a tricuspid valve plasty can solve the problem. However, the presence of pathologic tricuspid valve structures makes in general more specific plastic surgical procedures and even prosthetic valve replacements necessary. A typical example for a structural tricuspid valve regurgitation is the case of a traumatic papillary muscle rupture. Due to the sudden onset, this pathology is not well tolerated and requires in general surgical reinsertion of the papillary muscle. In contrast, tricuspid valve regurgitation resulting from chronic pulmonary embolism with pulmonary artery hypertension, can be improved by pulmonary artery thrombendarteriectomy and even completely cured with an additional tricuspid annuloplasty. However, tricuspid regurgitations due to terminal heart failure are not be addressed with surgery directed to tricuspid valve repair or replacement. Heart transplantation, dynamic cardiomyoplasty or mechanical circulatory support should be evaluated instead.

Strut fracture of Björk-Shiley convexo-concave valve in Japan--risk of small valve size--.

PubMed

Watarida, S; Shiraishi, S; Nishi, T; Imura, M; Yamamoto, Y; Hirokawa, R; Fujita, M

2001-08-01

The Björk-Shiley convexo-concave (BSCC) prosthetic valve was introduced in 1979. Between 1979 and 1986, approximately 86,000 BSCC valves were implanted. By December 31, 1994, 564 complete strut fractures had been reported to the manufacture. We experienced a case of an outlet strut fracture and investigated the risk of BSCC prosthetic valve fractures in Japan. To investigate the risk factor of a strut fracture in Japan, we investigated published cases of strut fractures. Between 1979 and 1986, 2021 BSCC valves were implanted in Japan. By January 31, 2000, 11 complete strut fractures of 60-degree BSCC valves including our case had occurred. The patients were eight males and three females. The average age at valve replacement was 42.4+/-8.1 years, and nine of eleven (81.8%) were patients < 50 years-old. The average age of the patients when the BSCC valve fractured was 47.7+/-6.4 years, and eight of eleven (72.7%) were patients <= 50 years old. All patients were implanted in the mitral position. The sizes of the BSCC valve were 27 mm (n=5) (45.5%), 29 mm (n=3) (27.2%), and 31 mm (n=3) (27.2%). Four patients died and seven patients survived. Although only 11 BSCC valve struts fractured and statistical analysis could not be performed, our findings suggest that the high risk group for a strut fracture in Japan is young male patients with a mitral valve, >= 27 mm in size with BSCC models manufactured before March 1982. When following-up patients with BSCC models manufactured before March 1982, the possibility of a strut fracture in all BSCC valve sizes should be kept in mind.

Tricuspid regurgitation and right ventricular function after mitral valve surgery with or without concomitant tricuspid valve procedure.

PubMed

Desai, Ravi R; Vargas Abello, Lina Maria; Klein, Allan L; Marwick, Thomas H; Krasuski, Richard A; Ye, Ying; Nowicki, Edward R; Rajeswaran, Jeevanantham; Blackstone, Eugene H; Pettersson, Gösta B

2013-11-01

To study the effect of mitral valve repair with or without concomitant tricuspid valve repair on functional tricuspid regurgitation and right ventricular function. From 2001 to 2007, 1833 patients with degenerative mitral valve disease, a structurally normal tricuspid valve, and no coronary artery disease underwent mitral valve repair, and 67 underwent concomitant tricuspid valve repair. Right ventricular function (myocardial performance index and tricuspid annular plane systolic excursion) was measured before and after surgery using transthoracic echocardiography for randomly selected patients with tricuspid regurgitation grade 0, 1+, and 2+ (100 patients for each grade) and 93 with grade 3+/4+, 393 patients in total. In patients with mild (<3+) preoperative tricuspid regurgitation, mitral valve repair alone was associated with reduced tricuspid regurgitation and mild worsening of right ventricular function. Tricuspid regurgitation of 2+ or greater developed in fewer than 20%, and right ventricular function had improved, but not to preoperative levels, at 3 years. In patients with severe (3+/4+) preoperative tricuspid regurgitation, mitral valve repair alone reduced tricuspid regurgitation and improved right ventricular function; however, tricuspid regurgitation of 2+ or greater returned and right ventricular function worsened toward preoperative levels within 3 years. Concomitant tricuspid valve repair effectively eliminated severe tricuspid regurgitation and improved right ventricular function. Also, over time, tricuspid regurgitation did not return and right ventricular function continued to improve to levels comparable to that of patients with lower grades of preoperative tricuspid regurgitation. In patients with mitral valve disease and severe tricuspid regurgitation, mitral valve repair alone was associated with improved tricuspid regurgitation and right ventricular function. However, the improvements were incomplete and temporary. In contrast, concomitant

Method of Manufacturing Carbon Fiber Reinforced Carbon Composite Valves

NASA Technical Reports Server (NTRS)

Rivers, H. Kevin (Inventor); Ransone, Philip O. (Inventor); Northam, G. Burton (Inventor)

1998-01-01

A method for forming a carbon composite valve for internal combustion engines is discussed. The process includes the steps of braiding carbon fiber into a rope thereby forming a cylindrically shaped valve stem portion and continuing to braid said fiber while introducing into the braiding carbon fiber rope a carbon matrix plug having an outer surface in a net shape of a valve head thereby forming a valve head portion. The said carbon matrix plug acting as a mandrel over which said carbon fiber rope is braided, said carbon fiber rope and carbon matrix plug forming a valve head portion suitable for mating with a valve seat; cutting said braided carbon valve stem portion at one end to form a valve tip and cutting said braided carbon fiber after said valve head portion to form a valve face and thus provide a composite valve preform; and densifying said preform by embedding the braided carbon in a matrix of carbon to convert said valve stem portion to a valve stem and said valve head portion to a valve head thereby providing said composite valve.

Lightweight Valve Closes Duct Quickly

NASA Technical Reports Server (NTRS)

Fournier, Walter L.; Burgy, N. Frank

1991-01-01

Expanding balloon serves as lightweight emergency valve to close wide duct. Uninflated balloon stored in housing of duct. Pad resting on burst diaphragm protects balloon from hot gases in duct. Once control system triggers valve, balloon inflates rapidly to block duct. Weighs much less than does conventional butterfly, hot-gas, or poppet valve capable of closing duct of equal diameter.

Development of Mitral Stenosis After Mitral Valve Repair: Importance of Mitral Valve Area.

PubMed

Chan, Kwan Leung; Chen, Shin-Yee; Mesana, Thierry; Lam, Buu Khanh

2017-12-01

The development of mitral stenosis (MS) is not uncommon after mitral valve (MV) repair for degenerative mitral regurgitation (MR), but the significance of MS in this setting has not been defined. We prospectively studied 110 such patients who underwent supine bicycle exercise testing to assess intracardiac hemodynamics at rest and at peak exercise. B-type natriuretic peptide (BNP) levels were measured at rest and after the exercise test. The patients also performed the 6-minute walk test and completed the 36-Item Short Form Survey (SF-36). Follow-up was performed by a review of the medical record and telephone interview. Of 110 patients, 22 had MS defined by a mitral valve area (MVA) ≤ 1.5 cm 2 . The resting and peak exercise mitral gradients and pulmonary artery systolic pressure were significantly higher in patients with MS compared with patients with an MVA > 1.5 cm 2 . BNP levels at rest and after exercise were also higher in the patients with MS, who also had lower exercise capacity and worse perception of well-being in 3 domains (physical function, vitality, and social function) on the SF-36. MVA had higher specificity and positive predictive value in predicting outcome events compared with a mean gradient of 3 or 5 mm Hg. In patients who had MV repair for degenerative MR, an MVA ≤ 1.5 cm 2 occurs in about one-fifth of patients and is associated with adverse intracardiac hemodynamics, lower exercise capacity, and adverse outcomes. Copyright © 2017 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

Energy conservation with automatic flow control valves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phillips, D.

Automatic flow control valves are offered in a wide range of sizes starting at 1/2 in. with flow rates of 0.5 gpm and up. They are also provided with materials and end connections to meet virtually any fan-coil system requirement. Among these are copper sweat type valves; ductile iron threaded valves; male/female threaded brass valves; and combination flow control/ball valves with union ends.

Conventional Surgery for Early and Late Symptomatic Mitral Valve Stenosis After MitraClip® Intervention: An Institutional Experience With Four Consecutive Patients.

PubMed

Alozie, Anthony; Paranskaya, Liliya; Westphal, Bernd; Kaminski, Alexander; Steinhoff, Gustav; Sherif, Mohammad; Ince, Hüseyin; Öner, Alper

2017-12-01

Surgical mitral valve repair is the gold standard for treatment of mitral regurgitation. Recently, the transcatheter treatment of mitral regurgitation with the MitraClip ® device (Abbot Vascular Structural Heart, Menlo Park, CA) has demonstrated promising results in treating patients not amenable for surgical correction of mitral valve regurgitation. Most patients reported in the literature requiring surgical bailout after MitraClip treatment presented with residual or recurrent mitral valve regurgitation. Mitral valve stenosis after MitraClip treatment has been rarely reported. From February 2010 to December 2014, four patients out of 165 patients who underwent MitraClip therapy developed symptomatic mitral valve stenosis (2.4%) and needed surgical correction. Data of the four patients were reviewed retrospectively. Follow-up data were obtained from each patient's general practitioner/cardiologist by phone calls and facsimile and were complete in all patients. All four patients were treated with ≥ 2 MitraClip (MC) devices during their initial presentation. All four patients underwent MV replacement with a tissue valve. The postoperative course was uneventful and there was no 30-day mortality. At 6-month follow-up, all patients were alive and in NYHA class I-III. Placement of multiple clip devices may lead to slightly elevated transmitral gradients. This may not necessarily interpret into symptomatic mitral stenosis. However, in some cases this is possible. Caution should be exercised at this phase of the learning curve of the percutaneous MC treatment, especially in use of multiple MC devices. Copyright © 2017 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

Dual motion valve with single motion input

NASA Technical Reports Server (NTRS)