Effect of Leaflet Laceration on TAVR Fluid Mechanics and Comparison with SAVR

Abstract

Background Leaflet thrombosis after surgical and transcatheter aortic valve replacement (SAVR and TAVR) may be caused by blood flow stagnation in the native- and neo-sinus regions. To date, aortic leaflet laceration has been used to mitigate coronary obstruction following TAVR; however, its impact on the fluid mechanics of the native and neo-sinus regions is poorly understood. This in vitro study compares the flow velocities and flow patterns in the setting of SAVR vs. TAVR with and without aortic leaflet lacerations.
Methods Two valves (23-mm PERIMOUNT and 26 mm SAPIEN 3 valve) were studied in a validated mock flow loop under physiologic conditions. Neo-sinus and native sinus fluid mechanics were quantified using particle image velocimetry in the left and non-coronary cusp, with an increasing number of aortic leaflets lacerated or removed.
Results Across all conditions, SAVR had the highest average sinus and neo-sinus velocities, and this value was used as a reference to compare against the TAVR conditions. With an increasing number of leaflets lacerated or removed with TAVR, the average sinus and neo-sinus velocities increased from 25% to 70% of SAVR flow (100%). Diastolic velocities were substantially augmented by leaflet laceration. Also, the shorter frame of the SAVR led to higher flow velocities as compared to the longer frame of the TAVR, even after complete leaflet removal.
Conclusions Leaflet laceration augmented TAVR native- and neo-sinus flow fields approaching that of SAVR. These findings may have potential clinical implications for the use of single or multiple leaflet lacerations to reduce leaflet thrombosis and thus potentially improve TAVR durability.

Keywords: transcatheter aortic valve replacement (TAVR); SAVR; thrombosis; BASILICA; bioprosthetic heart valve failure; coronary artery obstruction.