85Patient-specific computer simulation to elucidate the role of contact pressure in the development of new conduction abnormalities after catheter based implantation of a self-expanding aortic valve

Background: The extent to which pressure generated by the valve on the aortic root plays a role in the genesis of conduction abnormalities after TAVR is unknown. Purpose: To elucidate the role of contact pressure and contact pressure area in the development of conduction abnormalities after transcatheter aortic valve replacement (TAVR) using patient-specific computer simulations. Methods: Finite-element computer simulations were performed to simulate TAVR of 112 patients who had undergone TAVR with the self-expanding CoreValve/Evolut R valve. Based on pre-operative multi-slice computed tomography (MSCT), a patient-specific region of the aortic root containing the atrioventricular conduction system was determined by identifying the membranous septum. Contact pressure and contact pressure index (percentage of are subjected to pressure) were quantified and compared in patients with and without new conduction abnormalities. Results: Sixty-two patients (55%) developed a new left bundle branch block or a high degree atrioventricular block after TAVR. Maximum contact pressure and contact pressure index (median [IQR]) were significantly higher in patients with compared to those without new conduction abnormalities (0.47MPa [0.40–0.67] and 35% [22–46], respectively versus 0.25MPa [0.01–0.43] and 13% [0–28]). By multivariate regression analysis only maximum contact pressure (OR: 1.28, CI: 1.0–1.6, p=0.02) and contact pressure (OR: 1.54, CI: 1.1–2.1, p=0.01) were identified as independent predictors for conduction abnormalities, but not implantation depth.