Results 271 to 280 of about 64,339 (293)
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Cardiac Mechanics II: Heart Valves
2021Cardiac valves represent fundamental elements of cardiac function which directly interact with blood flow. The fluid dynamics of the aortic valve and of the mitral valve are here described in the normal operating conditions, first. Flow features in presence of valvular diseases are then discussed in conjunction with the technology available to evaluate
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MECHANICAL HEART VALVES AND PREGNANCY
Fetal and Maternal Medicine Review, 2007Mechanical heart valves pose a particular challenge in pregnancy, as the primary agent used to prevent valve thrombosis, coumadin (warfarin), is a known teratogen. Alternatives to coumadin, such as unfractionated heparin (UFH) and low-molecular weight heparin (LMWH) are safer for the fetus, particularly during the first trimester of pregnancy, but ...
CYNTHIA MAXWELL, MATHEW SERMER
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Cavitation Suppression of Bileaflet Mechanical Heart Valves
Cardiovascular Engineering and Technology, 2020Mechanical heart valves (MHVs) are widely used to replace diseased heart valves, but it may suffer from cavitation due to the rapid closing velocity of the leaflets, resulting in the damage of red blood cells and platelets. The aim of this study is to apply computational fluid dynamics (CFD) method to investigate the cavitation in bileaflets mechanical
Jin-yuan Qian +3 more
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Phonographic detection of mechanical heart valve thrombosis
Journal of Artificial Organs, 2017The formation of thrombotic deposits affects the functionality of mechanical prosthetic heart valves; as a consequence, mechanical valves thrombosis needs early diagnosis to prevent thromboembolic events. This paper compares the acoustic signals produced by two commercial bileaflet mechanical heart valves in the closing phase to detect the presence of ...
Tosoni, Simone +4 more
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Problems associated with mechanical heart valve sounds
European Journal of Cardio-Thoracic Surgery, 1992A cross-sectional study of 50 randomly selected patients 12-36 months following mechanical heart valve replacement with Bjork-Shiley tilting disc valves was undertaken to investigate the factors which affect perception of, and reaction to, sounds generated by mechanical heart valves implanted in patients. Numerous problems were generated by the valves,
D, Limb, P H, Kay, A J, Murday
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Mechanical heart valves: 50 years of evolution
The Annals of Thoracic Surgery, 2003The past 50 years have witnessed remarkable progress in the development of safe, hemodynamically favorable mechanical heart valves. Starr-Edwards aortic and mitral ball valves introduced in the mid-1960s, continue to be used successfully worldwide. More than 100,000 Omniscience and Omnicarbon tilting-disc valves have been implanted since 1978 with ...
Vincent L, Gott +2 more
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Mechanical Heart Valve Cavitation: Valve Specific Parameters
The International Journal of Artificial Organs, 2004Several aspects of mechanical heart valve cavitation, in particular of “severe” vapor cavitation, have been investigated in order to describe the phenomenon of cavitation itself and to classify various mechanical heart valves with respect to their tendency to cavitation. Furthermore, following the results of the measurements, a model for determination
M J, Eichler, H M, Reul
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Psychoacoustic quantification of mechanical heart valve noise.
The Journal of heart valve disease, 2005Mechanical heart valves produce short clicking sounds during closure. These closing sounds are annoying for some patients and their partners by causing sleeping disorders or social embarrassment. Various methods for measuring the sounds have been developed both in vitro and in vivo using calculation of A-weighted sound pressure level or loudness ...
Nielsen, Thomas +4 more
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Squeeze Flow Measurements in Mechanical Heart Valves
ASAIO Journal, 2008High-speed squeeze flow during mechanical valve closure is often thought to cause cavitation, either between the leaflet tip and flat contact area in the valve housing, seating lip, or strut flat seat stop, depending on design. These sites have been difficult to measure within the housing, limiting earlier research to study of squeeze flow outside the ...
Lo, Chi-wen +4 more
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Dabigatran Use in Mechanical Heart Valve Patients
Future Cardiology, 2013Current guidelines have no recommendations on the utilization of novel oral anticoagulants, such as dabigatran, for the prevention of thromboembolic events in patients with mechanical heart valves. However, recent studies on the use of dabigatran in patients with atrial fibrillation and animal studies have suggested a new potential role for dabigatran ...
Farnoosh, Zough +2 more
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