Stagger-folding leaflet design for improved durability in transcatheter heart valves

Transcatheter valve replacement has become the established standard therapy for inoperable, high- and intermediate-risk patients with severe symptomatic aortic stenosis. Leaflet damage due to mechanical loading of the transcatheter valve during crimping process is a significant cause of premature structural valve degeneration. In this study, a novel stagger-folding transcatheter heart valve (THV) was designed to reduce the stress concentration caused by crimping process. The spatial distribution of the leaflets during the crimping process was optimized through axial stagger-folding, effectively mitigating inter-leaflet compression, reducing the risk of leaflet damage, which may enhance the long-term durability of the leaflets. Numerical simulation and multi-objective optimization were employed to optimize the axial displacements of stagger-folding leaflets, and a stagger-folding valve stent was designed based on the optimized design. Compared to conventional normal-folding valve, the novel stagger-folding valve demonstrated significant reductions in damage volume (23.64%), effectively reducing the stress caused by the folding of the valve leaflets. Consequently, the novel THV proposed in this study demonstrated significant potential to mitigate leaflet stress caused by crimping and may enhance valve durability, providing technical support for extending THV service life.