نتایج جستجو برای: mechanical heart valve
تعداد نتایج: 681705 فیلتر نتایج به سال:
Polymer heart valves have been under investigation since the 1960s, but their success has been hampered by an overall lack of durability mainly due to calcification of the leaflets and a relatively high rate of thromboembolic complications. A new polymer (Quatromer) trileaflet design was tested for its thrombogenic potential and was compared to that of existing prosthetic heart valves routinely...
A 78-year-old woman was admitted to our institution with progressive dyspnea. She had previously been diagnosed with rheumatic heart disease and had undergone cardiac surgery for mechanical mitral valve replacement ten years previously. Transesophageal echocardiography revealed blockage of the mechanical prosthesis and the patient was scheduled for surgery, in which a thrombus was removed from ...
In this study, a polymeric aortic heart valve made of poly(vinyl alcohol) (PVA)-bacterial cellulose (BC) nanocomposite is simulated and designed using a hyperelastic non-linear anisotropic material model. A novel nanocomposite biomaterial combination of 15 wt % PVA and 0.5 wt % BC is developed in this study. The mechanical properties of the synthesized PVA-BC are similar to those of the porcine...
The heartbeat and blood flow signal to endocardial cell progenitors through mechanosensitive proteins that modulate the genetic program controlling heart valve morphogenesis. To date, the mechanism by which mechanical forces coordinate tissue morphogenesis is poorly understood. Here we use high-resolution imaging to uncover the coordinated cell behaviours leading to heart valve formation. We fi...
acute fulminant myocarditis is a life-threatening inflammatory disease of the myocardium characterized by the rapid deterioration of the hemodynamic status of the affected individual. with prompt recognition and appropriate management, complete recovery of ventricular function is likely within a few weeks. we introduce a 28-year-old man with acute fulminant myocarditis, who experienced circulat...
introduction: despite advances in cardiac surgery, many patients might still encounter some post-surgical complications and difficulties. to overcome such difficulties, they should receive the required education. in view of the fact that determining the educational needs is the first step in educational planning, the present study aims to determine the educational needs of patients undergoing h...
blunt injury to the chest can affect any one or all components of the chest wall and thoracic cavity. the clinical presentation of patients with blunt chest trauma varies widely and ranges from minor reports of pain to florid shock. traumatic tricuspid valve regurgitation is a rare cardiovascular complication of blunt chest trauma. tricuspid valve regurgitation is usually begotten by disorders ...
Prosthetic valve replacement remains the most viable alternative for the treatment of severely diseased heart valves. The cumulative experience of mechanical protheses and bioprostheses was evaluated for a 10-year performance comparison: Carpentier-Edwards standard porcine bioprosthesis (CE-S), 1,214 operations; Carpentier-Edwards supraannular porcine bioprosthesis (CE-SAV), 2,489; and mechanic...
To design more effective tissue-engineered heart valve replacements, the replacement tissue may need to mimic the biaxial stress-strain behavior of native heart valve tissue. This study characterized the planar biaxial properties of tissue-engineered valve leaflets and native aortic valve leaflets. Fibrin-based valve equivalent (VE) and porcine aortic valve (PAV) leaflets were subjected to incr...
Nearly 15 million people in the United States suffer from either aortic or mitral valvular disease. For patients with severe and symptomatic valvular heart disease, valve replacement surgery improves morbidity and mortality outcomes. In 2009, 90,000 valve replacement surgeries were performed in the United States. This review evaluates the advantages and disadvantages of mechanical and bioprosth...
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