Computational Fluid Dynamics Models for Leaflet Thrombosis Estimation Post-BASILICA

Background: Leaflet thrombosis has been suggested as the reason for the reduced leaflet motion in cases of hypoattenuated leaflet thickening of bioprosthetic aortic valves. This complication is mostly prevailed after transcatheter implantation in failed bioprosthetic valves (Valve-in-Valve; ViV). BASILICA technique, where the leaflets of the failed valve are lacerated, has been suggested to decrease the risk of leaflet thrombosis. This work aimed to estimate the risk of leaflet thrombosis post-ViV using several numerical approaches.

Methods: ViV configurations were calculated by modeling deployments of transcatheter aortic valve devices (Evolut, Sapien 3) in surgical Mitroflow with both intact and lacerated leaflets. The dry models were followed by computational fluid dynamics (CFD) simulations of the blood flow. Several approaches were implemented to estimate the risk locations for leaflet thrombosis. The considered approaches included both Lagrangian and Eulerian measures of near-wall stagnation and therefore.

Results: The different approaches indicate that there is a higher risk for leaflet thrombosis in the Sapien because of its intra-annular implantation. The BASILICA technique is shown to decrease the thrombogenicity but in the price of weaker support and anchorage for the implanted device.

Conclusion: Leaflet thrombosis remains pronounced in the latest generation of the transcatheter aortic valves devices and specifically, post-ViV. The current results can help guiding the clinicians in choosing the device with the lowest risk of leaflet thrombosis and valve mismatch. The proposed methods can also help optimizing future designs of transcatheter aortic valves with minimal thrombotic risks.