Results 271 to 280 of about 56,498 (290)

Mechanisms of bioprosthetic heart valve calcification1

Transplantation, 2003
Cryopreserved human heart valves are used in approximately 20% of the tissue heart valve procedures performed annually. The pathophysiology of allograft failure is not fully understood. The authors proposed the hypothesis that the rapid deterioration observed in some allograft heart valve recipients is caused by disruptive interstitial ice damage that ...
Ying C. Song, Kelvin G. M. Brockbank
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Mechanism for cavitation phenomenon in mechanical heart valves

Journal of Mechanical Science and Technology, 2006
Recently, cavitation on the surface of mechanical heart valve has been studied as a cause of fractures occurring in implanted Mechanical Heart Valves (MHVs). It has been conceived that the MHVs mounted in an artificial heart close much faster than in vivo sue, resulting in cavitation bubbles formation.
Hwansung Lee, Yoshiyuki Taenaka
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Phonographic detection of mechanical heart valve thrombosis

Journal of Artificial Organs, 2017
The 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, TARZIA, VINCENZO, COLLI, ANDREA, GEROSA, GINO, BAGNO, ANDREA   +4 more
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dynamics of mechanical heart valve prostheses [PDF]

WIT Transactions on Biomedicine and Health, 1970
A numerical code for analyzing the dynamic behaviour of heart valve prostheses is presented. The study is conducted with the valve in a simplified cardiovascular system, represented schematically by a circuit with a pump, the valve under test, a rugged elastic tube and a capacity.
BELFORTE, GUIDO, RAPARELLI, TERENZIANO, EULA, Gabriella   +2 more
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Developments in mechanical heart valve prosthesis

Sadhana, 2003
Artificial heart valves are engineered devices used for replacing diseased or damaged natural valves of the heart. Most commonly used for replacement are mechanical heart valves and biological valves. This paper briefly outlines the evolution, designs employed, materials being used,. and important factors that affect the performance of mechanical heart
C. V. Muraleedharan, Kalyani Nair, G. S. Bhuvaneshwar   +2 more
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Fluid Mechanics of Heart Valves and Their Replacements

Annual Review of Fluid Mechanics, 2016
As the pulsatile cardiac blood flow drives the heart valve leaflets to open and close, the flow in the vicinity of the valve resembles a pulsed jet through a nonaxisymmetric orifice with a dynamically changing area. As a result, three-dimensional vortex rings with intricate topology emerge that interact with the complex cardiac anatomy and give rise ...
Anvar Gilmanov, Trung Le, Fotis Sotiropoulos   +2 more
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MECHANISMS OF HEMOLYSIS IN PATIENTS WITH HEART VALVE PROSTHESES

Acta Medica Scandinavica, 1971
Abstract. Intravascular hemolysis was studied in a large, non‐selected series of patients with aortic and mitral valvular disease or valve prostheses in order to clarify the mechanisms of the erythrocyte destruction. Hemolysis was slight in unoperated patients, even in cases with severe valvular disease.
Jon Dale, Knut Rasmussen, Erik Myhre
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In Vivo Evaluation of a Trileaflet Mechanical Heart Valve

ASAIO Journal, 1994
Design goals for a mechanical heart valve include duplicating the hemodynamic performance of the natural valve, eliminating the need for anticoagulants, and maintaining safety. The Lapeyre-Dassault (Dassault-Aviation, Paris, France) prosthetic valve, undergoing development, addresses these goals.
B Rolland, Fuqua Jm, Steven M. Parnis, Philippe Perrier, Denton A. Cooley, O.H. Frazier, Jeff L. Conger, Macris Mp, Didier M. Lapeyre, Fred J. Clubb, H Reul   +10 more
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The closing velocity of mechanical heart valve leaflets

Medical Engineering & Physics, 1994
The closing motion of the occluder leaflets in bileaflet type mechanical heart valves (MHV) was monitored with a laser sweeping technique. The angular displacements of the leaflets were registered with precision of 0.2 microsecond steps. Experimental measurements were made using five 29 mm Edwards-Duromedics including three original specification (EDOS)
Tien Hon Chiang, Ned H. C. Hwang, R. C. Quijano, George X. Guo   +3 more
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Cardiac Mechanics II: Heart Valves

2021
Cardiac 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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