Leaflet thrombosis has been suggested as the reason for the reduced leaflet motion in cases of hypoattenuated leaflet thickening of bioprosthetic aortic valves. This work aimed to estimate the risk of leaflet thrombosis in two post-valve-in-valve (ViV) configurations, using five different numerical approaches. Realistic ViV configurations were calculated by modelling the deployments of the latest version of transcatheter aortic valve devices (Medtronic Evolut PRO, Edwards SAPIEN 3) in the surgical Sorin Mitroflow. Computational fluid dynamics simulations of blood flow followed the dry models. Lagrangian and Eulerian measures of near-wall stagnation were implemented by particle and concentration tracking, respectively, to estimate the thrombogenicity and to predict the risk locations. Most of the numerical approaches indicate a higher leaflet thrombosis risk in the Edwards SAPIEN 3 device because of its intra-annular implantation. The Eulerian approaches estimated high-risk locations in agreement with the wall sheer stress (WSS) separation points. On the other hand, the Lagrangian approaches predicted high-risk locations at the proximal regions of the leaflets matching the low WSS magnitude regions of both transcatheter aortic valve implantation models and reported clinical and experimental data. The proposed methods can help optimizing future designs of transcatheter aortic valves with minimal thrombotic risks.

在生物主动脉瓣膜小叶增厚程度低的情况下，小叶血栓形成被认为是小叶运动减少的原因。这项工作旨在使用五种不同的数值方法来估计两种瓣中瓣（ViV）配置中小叶血栓形成的风险。通过对最新版本的经导管主动脉瓣装置（Medtronic Evolut PRO、Edwards SAPIEN 3）在手术 Sorin Mitroflow 中的部署进行建模，计算出真实的 ViV 配置。血流的计算流体动力学模拟遵循干模型。分别通过粒子和浓度跟踪实施近壁停滞的拉格朗日和欧拉测量，以估计血栓形成并预测风险位置。大多数数值方法表明，由于 Edwards SAPIEN 3 装置是在瓣环内植入，因此其瓣叶血栓形成风险较高。欧拉方法估计的高风险位置与壁剪切应力 (WSS) 分离点一致。另一方面，拉格朗日方法预测了瓣叶近端区域的高风险位置，与经导管主动脉瓣植入模型的低 WSS 幅度区域相匹配，并报告了临床和实验数据。所提出的方法可以帮助优化经导管主动脉瓣的未来设计，并将血栓风险降至最低。