نتایج جستجو برای: heart valves
تعداد نتایج: 396404 فیلتر نتایج به سال:
"The exact mechanism for closure of the mitral valve is unknown." This was stated in a textbook on The heart, published in 1978.1 Ifthis problem has not yet been clarified it is not through lack of effort, the work of many authors having produced various ideas since Galen. Galen's clear appreciation of the function of the heart valves is evident from the following passage: "The common purpose o...
Valvular heart disease is a pathologic process involving one or more of the four valves (aortic, pulmonary, mitral and tricuspid) of the heart typified by stenosis or regurgitation and leading to patient symptoms. The most common causes are tissue degeneration, rheumatic fever and congenital heart diseases. Aortic valve replacement (AVR) using either mechanical or bioprosthetic (tissue) valves ...
Many problems and complications associated with heart valves are related to the dynamic behavior of the valve and the resultant unsteady flow patterns. An accurate depiction of the spatial and temporal velocity and rms distributions imparts better understanding of flow related valve complications, and may be used as a guideline in valve design. While the generalized correlation between increase...
BACKGROUND Tissue engineering using in vitro-cultivated autologous vascular wall cells is a new approach to biological heart valve replacement. In the present study, we analyzed a new concept to process allogenic acellular matrix scaffolds of pulmonary heart valves after in vitro seeding with the use of autologous cells in a sheep model. METHODS AND RESULTS Allogenic heart valve conduits were...
Current research on valvular heart repair has focused on tissue-engineered heart valves (TEHV) because of its potential to grow similarly to native heart valves. Decellularized xenografts are a promising solution; however, host recellularization remains challenging. In this study, decellularized porcine aortic valves were implanted into the right ventricular outflow tract (RVOT) of sheep to inv...
Background: Heart valve disease gradually increases the pressure in the heart chambers and impairs heart pumping. It influences on quality of life due to low output, disability, fear, amnesia, anxiety, and depression. Although most of signs and symptoms in patients with heart valve diseases may significantly decrease after valve replacement surgery, there is limited information about the impact...
CADIOVASCULAR sound may be divided into 2 categories,' namely, murmurs that result from turbulence in streams of blood flowing so rapidly that the critical Reynolds2' 3 number is exceeded and, heart sounds that represent vibrations resulting from abrupt changes in the velocity of blood movement. Since closure of the heart valves suddenly arrests or reverses the movement of blood, normal valve f...
BACKGROUND The majority of prosthetic heart valves currently implanted are tissue valves that can be expected to degenerate with time and eventually fail. Repeat cardiac surgery to replace these valves is associated with significant morbidity and mortality. Transcatheter heart valve implantation within a failed bioprosthesis, a "valve-in-valve" procedure, may offer a less invasive alternative. ...
BACKGROUND Glutaraldehyde-preserved bioprosthetic heart valve substitutes have limited performance and longevity due to tissue degeneration and calcification. The Freestyle valve (Medtronic Heart Valves, Inc, Minneapolis, MN) combines zero fixation pressure and proportional, variant-amino oleic acid (AOA) as antidegeneration and antimineralization measures. The aim of this study was to compare ...
The management of an intracranial hemorrhage in patients receiving anticoagulant therapy presents a significant challenge for medical professionals. Anticoagulant treatment is intended to prevent blood clotting, but it can worsen active brain bleeds. Despite this risk, avoiding the prothrombotic state caused by mechanical heart valves remains crucial. Guidelines on managing issue are currently ...
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