Numerical models for assessing the risk of leaflet thrombosis post-transcatheter aortic valve-in-valve implantation

Abstract

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.

Fluid–structure interaction analysis of eccentricity and leaflet rigidity on thrombosis biomarkers in bioprosthetic aortic valve replacements

“…22 Mayo et al analyzed the difference between two TAVR models on five different quantities of interest (QoIs) related to thrombogenic potential. 23 Their study consists of two phases: (a) A purely computational solid mechanics (CSM) model to deploy the stents and leaflets, followed by (b) a purely computational fluid dynamics (CFD) model to obtain the thrombosis QoIs for each TAVR, modeling the prostheses as rigid and fixed. It provides useful insight on how to quantify thrombogenic risk of TAVRs.…”

“…Though extensive bibliography exists for in vitro studies, in silico analyses of thrombogenic potential are still mainly restricted to ventricular assist devices 20,21 and aneurysms 22 . Mayo et al analyzed the difference between two TAVR models on five different quantities of interest (QoIs) related to thrombogenic potential 23 . Their study consists of two phases: (a) A purely computational solid mechanics (CSM) model to deploy the stents and leaflets, followed by (b) a purely computational fluid dynamics (CFD) model to obtain the thrombosis QoIs for each TAVR, modeling the prostheses as rigid and fixed.…”

Tissue-growth-based synthetic tree generation and perfusion simulation

“…Technologies associated with image-based blood flow simulations have evolved significantly over the last decades and some of the technologies are starting to be adapted in clinical applications (Colombo et al 2022;Gutiérrez et al 2021;Khan et al 2021;Marsden 2014;Nørgaard et al 2014;Plitman Mayo et al 2020;Regazzoni et al 2022;Schiavazzi et al 2017;Schollenberger et al 2021;Taylor and Figueroa 2009). The step towards actual clinical applications, however, is still challenging as there is much uncertainty in modeling patient-specific blood flow and pressure using medical image based geometries.…”

A model offluid–structureand biochemical interactions for applications to subclinical leaflet thrombosis

“…Prior work to model leaflet thrombosis has focused on computational fluid dynamics (CFD) simulations of blood flow through the valve. Plitman Mayo et al 6 performed CFD experiments of deployed transcatheter aortic valve replacements to determine areas of stagnated blood flow, suggesting possible sites of thrombosis formation. Vahidkhah et al 7 compared blood residence times behind the coronary and non‐coronary leaflets after a transcatheter aortic valve replacement (TAVR) procedure and determined similar residence times for all the leaflets.…”