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Mechanical Valve

Salma Ayoub, Giovanni Ferrari, Robert C Gorman, Joseph H Gorman, Frederick J Schoen, Michael S Sacks
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...
September 15, 2016: Comprehensive Physiology
Yingfei Xue, Vinayak Sant, Julie Phillippi, Shilpa Sant
Valvular heart diseases are the third leading cause of cardiovascular disease, resulting in more than 25,000 deaths annually in the United States. Heart valve tissue engineering (HVTE) has emerged as a putative treatment strategy such that the designed construct would ideally withstand native dynamic mechanical environment, guide regeneration of the diseased tissue and more importantly, have the ability to grow with the patient. These desired functions could be achieved by biomimetic design of tissue-engineered constructs that recapitulate in vivo heart valve microenvironment with biomimetic architecture, optimal mechanical properties and possess suitable biodegradability and biocompatibility...
October 22, 2016: Acta Biomaterialia
Mehrdad Namdari, Ali Eatemadi
Heart valves are currently under thorough investigation in tissue engineering (TE) research. Mechanical and biological heart valve prostheses which are recently used have several shortcomings. While allogenic and xenogenic biological prostheses are related to graft rejection, degeneration and thrombosis, resulting in a high rate of reoperation. Mechanical prostheses on the other hand are based on metallic, carbon, and polymeric components, and require continuous treatment with anticoagulant, which result in adverse reactions, e...
October 22, 2016: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
Yiwen Ouyang, Jingyi Li, Doris M Haverstick, James P Landers
We recently defined a magnetic bead-based assay that exploited an agglutination-like response for DNA and applied it to DNA-containing cell enumeration using inexpensive benchtop hardware [ J. Am. Chem. Soc. 2012 , 134 ( 12 ), 5689 - 96 ]. Although cost-efficient, the open-well format assay required numerous manual steps, and the magnetic field actuation scheme was not readily adaptable for integration. Here, we demonstrate a low-cost (<$2 in-lab), higher-throughput "pinwheel assay" platform that relies on a combination of a disposable rotation-driven microdisc (RDM), and a simple bidirectional rotating magnetic field (bi-RMF)...
October 25, 2016: Analytical Chemistry
Shohreh Maleki, Sanela Kjellqvist, Valentina Paloschi, Joelle Magné, Rui Miguel Mamede Branca, Lei Du, Kjell Hultenby, Johan Petrini, Jonas Fuxe, Janne Lehtiö, Anders Franco-Cereceda, Per Eriksson, Hanna M Björck
Individuals with a bicuspid aortic valve (BAV) are at significantly higher risk of developing aortic complications than individuals with tricuspid aortic valves (TAV) and defective signaling during the embryonic development and/or life time exposure to abnormal hemodynamic have been proposed as underlying factors. However, an explanation for the molecular mechanisms of aortopathy in BAV has not yet been provided. We combined proteomics, RNA analyses, immunohistochemistry, and electron microscopy to identify molecular differences in samples of non-dilated ascending aortas from BAV (N = 62) and TAV (N = 54) patients...
October 25, 2016: Scientific Reports
Inge A E W van Loosdregt, Sylvia Dekker, Patrick W Alford, Cees W J Oomens, Sandra Loerakker, Carlijn V C Bouten
Understanding cell contractility is of fundamental importance for cardiovascular tissue engineering, due to its major impact on the tissue's mechanical properties as well as the development of permanent dimensional changes, e.g., by contraction or dilatation of the tissue. Previous attempts to quantify contractile cellular stresses mostly used strongly aligned monolayers of cells, which might not represent the actual organization in engineered cardiovascular tissues such as heart valves. In the present study, therefore, we investigated whether differences in organization affect the magnitude of intrinsic stress generated by individual myofibroblasts, a frequently used cell source for in vitro engineered heart valves...
October 24, 2016: Cardiovascular Engineering and Technology
David Dobarro, Marian Urban, Karen Booth, Neil Wrightson, Javier Castrodeza, Jerome Jungschleger, Nicola Robinson-Smith, Andrew Woods, Gareth Parry, Stephan Schueler, Guy A MacGowan
BACKGROUND: This study examined whether aortic valve opening (AVO) and other echocardiographic parameters influence outcomes in patients on left ventricular (LV) assist device (LVAD) support. Pump thrombosis (PT) and ischemic stroke (IS) are known complications of LVAD, but mechanisms that could influence them are not completely understood. METHODS: This was a retrospective analysis of 147 patients who received a HeartWare Ventricular Assist Device ( HeartWare International) as a bridge to transplant or to candidacy between July 2009 and August 2015, of whom 126 had at least 30 days of follow-up before the first event (30-days-out cohort)...
August 18, 2016: Journal of Heart and Lung Transplantation
Per Martin Arvidsson, Johannes Töger, Marcus Carlsson, Katarina Steding-Ehrenborg, Gianni Pedrizzetti, Einar Heiberg, Hakan Arheden
Intracardiac blood flow is driven by hemodynamic forces that are exchanged between the blood and myocardium. Previous studies have been limited to 2D measurements or investigated only LV forces. Right ventricular forces and their mechanistic contribution to asymmetric redirection of flow in the RV have not been measured. We therefore aimed to quantify three-dimensional hemodynamic forces in both ventricles in a cohort of healthy subjects, using magnetic resonance imaging 4D flow measurements. 25 controls,14 elite endurance athletes, and two patients with left ventricular dyssynchrony were included...
October 21, 2016: American Journal of Physiology. Heart and Circulatory Physiology
Breanna L Alman, Evan Coffman, Anna Maria Siega-Riz, Thomas J Luben
BACKGROUND: Water and water-based beverages constitute a major part of daily fluid intake for pregnant women, yet few epidemiologic studies have investigated the role of water consumption on birth outcomes. METHODS: We used data from the National Birth Defects Prevention Study to conduct a case-control study investigating associations between maternal water consumption during pregnancy and birth defects (BD). We used interview data on water consumption during the first trimester of pregnancy in 14,454 cases (major BDs n ≥ 50) and 5,063 controls...
October 21, 2016: Birth Defects Research. Part A, Clinical and Molecular Teratology
Maral Ouzounian, Vivek Rao, Cedric Manlhiot, Nachum Abraham, Carolyn David, Christopher M Feindel, Tirone E David
BACKGROUND: Although aortic valve-sparing (AVS) operations are established alternatives to composite valve graft (CVG) procedures for patients with aortic root aneurysms, comparative long-term outcomes are lacking. OBJECTIVES: This study sought to compare the results of patients undergoing AVS procedures with those undergoing CVG operations. METHODS: From 1990 to 2010, a total of 616 patients age <70 years and without aortic stenosis underwent elective aortic root surgery (AVS, n = 253; CVG with a bioprosthesis [bio-CVG], n = 180; CVG with a mechanical prosthesis [m-CVG], n = 183)...
October 25, 2016: Journal of the American College of Cardiology
Marina Pieri, Alessandro Belletti, Fabrizio Monaco, Antonio Pisano, Mario Musu, Veronica Dalessandro, Giacomo Monti, Gabriele Finco, Alberto Zangrillo, Giovanni Landoni
BACKGROUND: In patients undergoing cardiac surgery, a reduced preoperative left ventricular ejection fraction (LVEF) is common and is associated with a worse outcome. Available outcome data for these patients address specific surgical procedures, mainly coronary artery bypass graft (CABG). Aim of our study was to investigate perioperative outcome of surgery on patients with low pre-operative LVEF undergoing a broad range of cardiac surgical procedures. METHODS: Data from patients with pre-operative LVEF ≤40 % undergoing cardiac surgery at a university hospital were reviewed and analyzed...
October 18, 2016: BMC Anesthesiology
Lindsey J Anstine, Chris Bobba, Samir Ghadiali, Joy Lincoln
Risk factors of heart valve disease are well defined and prolonged exposure throughout life leads to degeneration and dysfunction in up to 33% of the population. While aortic valve replacement remains the most common need for cardiovascular surgery particularly in those aged over 65, the underlying mechanisms of progressive deterioration are unknown. In other cardiovascular systems, a decline in endothelial cell integrity and function play a major role in promoting pathological changes, and while similar mechanisms have been speculated in the valves, studies to support this are lacking...
October 15, 2016: Journal of Molecular and Cellular Cardiology
Giordano Tasca, Matteo Selmi, Emiliano Votta, Paola Redaelli, Francesco Sturla, Alberto Redaelli, Amando Gamba
BACKGROUND: Aortic root aneurysm can be treated with valve-sparing procedures. The David and Yacoub techniques have shown excellent long-term results but are technically demanding. Recently, a new and simpler procedure, the Sleeve technique, was proposed with encouraging results. We aimed to quantify the biomechanics of the initially aneurysmal aortic root (AR) after the Sleeve procedure to assess whether it induces abnormal stresses, potentially undermining its durability. METHODS: Two finite element (FE) models of the physiologic and aneurysmal AR were built, accounting for the anatomical asymmetry and the nonlinear and anisotropic mechanical properties of human AR tissues...
October 15, 2016: Annals of Thoracic Surgery
M Saylik, K Gökkuş
BACKGROUND: Associated joint disorders with popliteal cysts were stated approximately between the ranges of 41-83 % in all reported cases. Combined treatment strategies that eliminate intra-articular pathologies and cyst- associated valve mechanisms are thought to be a good option in treatment of the disease. In this study, our main objective is to present clinical results of our combined treatment results, which includes posterior cyst excision with supine arthroscopic intervention, targeting intra-articular pathologies on recalcitrant cases...
October 18, 2016: BMC Musculoskeletal Disorders
Maria Vargas, Giuseppe Servillo
No abstract text is available yet for this article.
November 2016: Critical Care Medicine
Doris Barcellona, Lara Fenu, Francesco Marongiu
Oral anticoagulant therapies with the anti-vitamin K drugs (AVK), warfarin, acenocoumarol and phenprocoumon, are employed in primary and secondary anti-thrombotic prophylaxis in patients with venous thromboembolism, atrial fibrillation and cardiac mechanical valves. However, a monitoring test such as the International Normalized Ratio (INR) is required. The periodic monitoring of this therapy entails discomfort for the patients. Telemedicine and telecare can provide significant aid in the management of this therapy allowing patients to perform the test at home or anywhere else with a portable device, i...
October 18, 2016: Clinical Chemistry and Laboratory Medicine: CCLM
Benny Feng, Patricia Tang, Sharon Shui Yee Leung, Jayesh Dhanani, Hak-Kim Chan
BACKGROUND: Mechanically ventilated patients commonly suffer from ventilator-associated pneumonia, hypoxemia, and other lower respiratory tract infection as a result of pathogen colonization and poor sputum clearance. Consequently, there is a high rate of morbidity and mortality in these patients. Dry powder mannitol increases sputum clearance, and therefore, we developed a system to administer it to mechanically ventilated patients without disconnection from the ventilator. METHODS: The inspiratory line from a ventilator was split by using a three-way valve into two parallel lines where one contains a humidifier for normal breathing cycle and the other line contains a dry powder inhaler (Osmohaler™)...
October 18, 2016: Journal of Aerosol Medicine and Pulmonary Drug Delivery
Abhijeet V Naik, Parag S Bhalgat, Nilesh S Bhadane, Suresh V Joshi
Hemolytic anemia following a mitral valve repair is a very rare complication, with only 70 cases reported worldwide. We present a case of an 8-year-old girl who presented with a very early onset hemolytic anemia following a mitral valve repair with ring annuloplasty, which necessitated a reoperation. The report also discusses the various mechanisms of traumatic hemolysis associated with valve repair and probable lessons learnt and ways to avoid this complication.
September 2016: Indian Heart Journal
Linfeng Qian, Junnan Zheng, Hongfei Xu, Liping Shi, Lanjuan Li
BACKGROUND: Patients with respiratory failure caused by H7N9 may benefit from veno-venous, veno-arterial, and veno-veno-arterial extracorporeal membrane oxygenation (ECMO) support. CASE SUMMARY: A 55-year-old male patient was suffering from H7N9-caused acute respiratory distress syndrome (ARDS). He had a mechanical mitral and aortic valve replacement surgery and was using warfarin for anticoagulation. After prolonged mechanical ventilation, oxygen saturation was not improved...
October 2016: Medicine (Baltimore)
Sang Min Park, Haemin Jeong, Kyung-Soon Hong, Christopher Kim
BACKGROUND: In a patient underwent aortic valve replacement (AVR) due to bicuspid aortic valve (BAV) insufficiency without marked dilation of ascending aorta, the development of delayed-typed aneurysmal complication of ascending aorta has been often reported because the dilated aorta tends to grow insidiously with age. CASE SUMMARY: A 58-year-old man who underwent AVR with mechanical valve due to severe aortic regurgitation secondary to BAV 7 years previously presented with exertional chest discomfort for 1 year...
October 2016: Medicine (Baltimore)
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