Effect of Initial Opening Morphology of Polymeric Valves on Hemodynamic Performance.

Purpose: In order to explore the correlation between the initial morphology of the valve and hemodynamic and valve dynamic performance, this study is based on the fact that polymeric prostheses are more convenient to manufacture, and have the possibility of preparing complex geometric shapes and directly obtaining the initial morphologies of different valves, aims to research the effect of different initial opening morphologies of polymeric valves on hemodynamic performance.

Method: Valve models with different opening shapes were established. Polyurethane materials were used to manufacture the valve samples by dip-coating molding. The stress distribution of three different initial opening shapes was compared by finite element simulation. The hemodynamics and the leaflets dynamic performance of the three polymeric valves were analyzed by in vitro pulsatile flow experiments and particle image velocity measurement experiments.

Results: The valve morphology at 0.025s, 0.053s, and 0.079s was selected as the initial shape and was recorded as PHV1, PHV2, and PHV3. Finite element analysis found that during the systolic phase, the stress concentration area of PHV1 was the highest among the three types of valves, while during the diastolic phase, the stress concentration area of PHV1 was the lowest. Similarly, the maximum principal strain of PHV1, PHV2, and PHV3 decreased in turn at the time of peak systole but increased in turn at the time of peak diastole. In vitro testing results showed that valves with smaller opening areas had smaller regurgitant volume, while valves with larger opening areas had larger EOA, as well as smaller vorticity and viscous shear stress.

Conclusion: Valves with a smaller initial opening area have a better effect in preventing regurgitation, whereas valve with a larger initial opening area has a larger opening area and a lower risk of thrombosis. Therefore, comprehensive considerations are needed when designing the initial morphology of the polymeric artificial heart valve.