Cardiac Valve Replacement with Mechanical Prostheses: Current Status and Trends

Teijeira, F. Javier; Mikhail, Adel A.

doi:10.1007/978-1-4757-4421-7_13

Cited by 4 publications

(2 citation statements)

References 56 publications

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“…The problems encountered with most of the existing artificial heart valves are well documented in the literature, and a number of alternative designs were suggested and hydrodynamically examined by many researchers (6)(7)(8)(9)(10)(11)(12)(13)(14)(15). Although the results from these studies revealed good correlative information between in vitro measurements and in vivo clinical and pathological findings, they highlighted the need for biocompatible, hydrodynamically efficient, costeffective prosthetic heart valves.…”

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confidence: 99%

Flow Characteristics Past Jellyfish and St. Vincent Valves in the Aortic Position Under Physiological Pulsatile Flow Conditions

Morsi

Sakhaeimanesh

2000

Artificial Organs

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Thrombus formation and hemolysis have been linked to the dynamic flow characteristics of heart valve prostheses. To enhance our understanding of the flow characteristics past the aortic position of a Jellyfish (JF) valve in the left ventricle, in vitro laser Doppler anemometry (LDA) measurements were carried out under physiological pulsatile flow conditions. The hemodynamic performance of the JF valve was then compared with that of the St. Vincent (SV) valve. The comparison was given in terms of mean systolic pressure drop, back flow energy losses, flow velocity, and shear stresses at various locations downstream of both valves and at cardiac outputs of 3.5 L/min, 4.5 L/min, and 6.5 L/min respectively. The results indicated that both valves created disturbed flow fields with elevated levels of turbulent shear stress as well as higher levels of turbulence in the immediate vicinity of the valve and up to 1 diameter of the pipe (D) downstream of the valve. At a location further downstream, the JF valve showed better flow characteristics than the SV in terms of velocity profiles and turbulent shear stresses. The closure volume of the SV valve was found to be 2.5 times higher than that of the JF valve. Moreover, the total back flow losses and mean systolic pressure drop also were found to be higher in the SV than the JF valve.

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confidence: 99%

Flow Characteristics Past Jellyfish and St. Vincent Valves in the Aortic Position Under Physiological Pulsatile Flow Conditions

Morsi

Sakhaeimanesh

2000

Artificial Organs

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“…Prosthetic valves are geometrically very complex and the shape and/or motion of their leaflets are not known a priori, rather, it evolves dynamically in response to the instantaneous flow conditions [6]. For mechanical heart valves (MHVs) this is somewhat alleviated through several accepted design parameters [7,8], for example, leakage flow upon valve closure, intended to scour critical areas of the valve such as the hinges and the areas between the leaflet edges and the housing. However, traditional design matrix approaches for optimizing such devices are only of limited utility, as the optimization process is very specific to the device design characteristics and its inherent geometric constraints.…”

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confidence: 99%