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Fluid shear stress in prosthetic heart valves

1977; Elsevier BV; Volume: 10; Issue: 5-6 Linguagem: Inglês

10.1016/0021-9290(77)90003-3

1873-2380

E. J. Roschke, Earl C. Harrison,

Hydraulic and Pneumatic Systems

A semiempirical approach has been developed to estimate the fluid shear stress developing between the valve seat and moving poppet during the opening sequence of an aortic ball valve and a disk valve prosthesis. The assumption of laminar quasi-steady flow is shown to be conservative. The laminar shear stresses calculated by this method are large, and exceed threshold levels for incipient hemolysis. Results are compared to a circular-orifice valve, for which much lower shear stresses are evident. Paravalvular leaks are considered as well, and shear stresses derived from a turbulent free-jet analysis indicate that such leaks could lead to incipient hemolysis if significant pressure drops occur across the leak. The overall results indicate that prosthetic heart valves tend to generate a condition of mild chronic hemolysis, a condition that may not be as innocuous as has been assumed in the past.