Mechanics Post-TAVR for Trileaflet vs Bicuspid Aortic Valves

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.