Mechanics Post-TAVR for Trileaflet vs Bicuspid Aortic Valves: Insights from Computational Simulation.

BACKGROUND

Bicuspid aortic valve (BAV) disease is the most common congenital heart defect and is associated with elliptical openings and excess calcification. Limited data are available on long-term efficacy of transcatheter aortic valve replacement (TAVR) for BAV patients.

OBJECTIVES

The purpose of this study was to compare simulated mechanical metrics post-TAVR between BAV and trileaflet patients with calcific aortic stenosis.

METHODS

Pre-TAVR computed tomography scans of trileaflet (n = 22) and BAV (n = 25) were used to segment the aortic valve. Simulated balloon-expandable stent deployment was performed from a previously developed protocol. The bioprosthetic leaflets were then pressurized under a physiological pressure. Stent waist expansion ratio, aspect ratio (AR), leaflet systolic normalized geometric orifice area (GOA), and maximum leaflet diastolic stress were measured.

RESULTS

BAVs had lower waist expansion ratio (87.8% ± 2.6% vs 89.4% ± 1.4%; P < 0.001), lower waist AR (94.6% ± 2.8% vs 98.2% ± 1.0%; P < 0.001), lower normalized GOA (88.9% ± 0.8% vs 89.5% ± 0.7%; P < 0.01), and higher maximum stress (2.81 ± 0.44 vs 2.29 ± 0.25 MPa; P < 0.001) on average compared to trileaflet patients, respectively. Within the BAV group, calcium volume was correlated with waist AR (r = -0.75, P < 0.001), normalized GOA (r = -0.68, P < 0.001), and maximum stress (r = 0.66, P < 0.001).

CONCLUSIONS

Balloon-expandable TAVR for BAV has worse simulated mechanical metrics compared to TAVR for trileaflet aortic valve patients and is associated with high calcium volume.