Hemodynamics of a Bileaflet Mechanical Heart Valve with Different Levels of Dysfunction

TL;DR

This study investigates how varying levels of leaflet dysfunction in bileaflet mechanical heart valves affect blood flow dynamics, revealing increased velocities, pressure drops, and wall shear stresses with higher dysfunction levels.

Contribution

It provides detailed flow analysis of a bileaflet mechanical heart valve with asymmetric leaflet dysfunction, highlighting the impact on hemodynamics and potential implications for valve performance.

Findings

Increased velocities and shear stresses with higher dysfunction levels.

Pressure drops increased by up to 300% as dysfunction progressed.

Higher net shear forces on both leaflets due to dysfunction.

Abstract

Heart disease is one of leading causes of mortality worldwide. Healthy heart valves are key for proper heart function. When these valves dysfunction, a replacement is often necessary in severe cases. The current study presents an investigation of the pulsatile blood flow through a bileaflet mechanical heart valve (BMHV) where one leaflet is healthy and can fully open and the other leaflet cannot fully open with different levels of dysfunction. To better understand the implications that a dysfunctional leaflet has on the blood flow through these valves, analysis of flow characteristics such as velocity, pressure drop, wall shear stress and vorticity profiles was performed. Results suggested that leaflet dysfunction caused increased local velocities, separation regions and wall shear stresses. For example, the maximum velocity increased from 2.53 m/s to 4.9 m/s when dysfunction increased from 0% to 100%. The pressure drop increased (by up to 300%) with dysfunctionality. Results suggested that leaflet dysfunction also caused increased wall shear stresses on the valve frame where higher stresses developed around the hinges (at 75% and 100% dysfunctions). Analysis also showed that increased dysfunctionality of one leaflet led to higher net shear forces on both the healthy and dysfunctional leaflets (by up to 200% and 600%, respectively).