Key result
The water hammer effect and high-speed leakage flow effect are the primary causes of cavitation in bileaflet mechanical heart valves, with cavitation occurring during the fully closing stage.
Why the study?
Mechanical heart valves can cause potential complications like hemolysis and thrombosis due to hemodynamic characteristics, prompting investigation into blood flow features and cavitation mechanisms in bileaflet mechanical heart valves.
The study identifies the water hammer effect and high-speed leakage flow as primary causes of cavitation in bileaflet mechanical heart valves, providing insights for cavitation suppression.
Water hammer and leakage flow drive cavitation in closing phase; hypothesis-generating for valve design, with human translation unproven.
A mechanical heart valve (MHV) is an effective device to cure heart disease, which has the advantage of long life and high reliability. Due to the hemodynamic characteristics of blood, mechanical heart valves can lead to potential complications such as hemolysis, which have damage to the blood elements and thrombosis. In this paper, flowing features of the blood in the valve are analyzed and the cavitation mechanism in bileaflet mechanical heart valve (BMHV) is studied. Results show that the water hammer effect and the high-speed leakage flow effect are the primary causes of the cavitation in the valve. Compared with the high-speed leakage flow effect, the water hammer has a greater effect on the cavitation strength. The valve goes through four kinds of working condition within one heart beating period, including, fully opening stage, closing stage and fully closing stage. These four stages, respectively, make up 8.5%, 16.1%, 4.7% and 70.7% of the total period. The cavitation occurs on the fully closing stage. When the valve is in closing stage, the high pressure downstream of the valve lasts for about 20 ms and the high-speed leakage flow lasts for about 200 ms. This study systematically analyzes the causes of cavitation emerged in the process of periodic motion, which proposes the method for characterizing the intensity of the cavitation, and can be referred to for the cavitation suppression of the BHMV and similar valves.
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Li et al. (2020) studied this question. Bileaflet mechanical heart valve (BMHV) was evaluated on Cavitation mechanism and flowing features. The water hammer effect and high-speed leakage flow effect are the primary causes of cavitation in bileaflet mechanical heart valves, with cavitation occurring during the fully closing stage.
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