Article Impact Level: HIGH Data Quality: STRONG Summary of Journal of Fluid Mechanics. https://doi.org/10.1017/jfm.2025.354 Dr. Syed Samar Abbas et al.
Points
- Aortic heart valve function prevents regurgitant flow from the aorta into the left ventricle.
- Bileaflet mechanical heart valves (BMHVs) show higher regurgitant flow due to delayed closure compared to bioprosthetic (BHVs).
- TMHVs and BHVs close during systolic deceleration due to a central jet-dominant flow creating a central low-pressure zone.
- BMHVs only close when flow reverses because their triple-jet flow maintains near-equal pressure across leaflets until late systole.
- Generating a strong central jet and central leaflet closure are crucial design principles for early valve closure and minimal regurgitation.
Summary
This study investigated the closure dynamics of various aortic heart valves, specifically comparing bileaflet mechanical heart valves (BMHVs) with trileaflet mechanical heart valves (TMHVs) and bioprosthetic heart valves (BHVs), under similar physiological conditions using fluid–structure interaction simulations. The primary function of aortic valves is to prevent regurgitant flow from the aorta into the left ventricle. Previous observations indicate that BMHVs exhibit higher regurgitant flow due to delayed closure compared to BHVs. This research aimed to elucidate the underlying hemodynamic mechanisms responsible for these differential closure patterns.
The simulations revealed that TMHVs and BHVs initiate closure during the systolic deceleration phase, whereas BMHVs only begin to close when the aortic flow reverses. This critical difference in closure timing was attributed to distinct hemodynamic flow patterns generated by the valves when fully opened. TMHVs and BHVs produce a central jet-dominant flow. During late systole, the deceleration of this central jet is higher than that within the aortic sinuses, creating a lower central pressure. This pressure gradient effectively drives the leaflets of TMHVs and BHVs towards the center, initiating early closure.
In contrast, BMHVs generate a triple-jet flow pattern, where the lateral jets are wider than the central jet. Consequently, the pressure on both the sinus-side and central flow-side of the BMHV leaflets remains nearly equivalent until the very end of systole, failing to create the necessary pressure differential for early closure. Contrary to classical beliefs, the study found no evidence that sinus vortices generate significant high pressure or viscous stresses to initiate valve closure. The findings suggest that the design principles promoting a strong central jet and central leaflet closure are crucial for ensuring early valve closure and minimizing regurgitation, offering insights for future valve design.
References
Abbas, S. S., Asadi, H., & Borazjani, I. (2025). Closure dynamics of aortic mechanical heart valves versus bioprosthetic heart valves. Journal of Fluid Mechanics, 1012, A3. https://doi.org/10.1017/jfm.2025.354
