Validating In Silico and In Vitro Patient-Specific Structural and Flow Models with Transcatheter Bicuspid Aortic Valve Replacement Procedure

Mild Paravalvular Leak May Pose an Increased Thrombogenic Risk in Transcatheter Aortic Valve Replacement (TAVR) Patients-Insights from Patient Specific In Vitro and In Silico Studies

“…Sizing functions followed similar studies [23][24][25][26], and additional mesh and temporal convergence were confirmed with cell numbers between 2.9 and 2.5 million cells for the models as well as a constant 0.5 ms fixed timestep. Laminar flow solution was assumed, following previous CFD studies of PVL flows [23,24,26,36], and confirmed by calculating the average Reynolds number along the streamlines during peak diastole between 115-236 and instantaneous maximum Re between 990-1917 (See Supplementary Figures S3-S5). Inlet/outlet extensions (6 cm) were added from the LVOT to the ventricular inlet and from the ascending aorta to the aortic outlet.…”

“…Both in vitro and in silico models rely on assumptions of the tissue material properties and are arguably more critical in patient-specific simulations. The standard methodology for patient-specific TAVR simulations in literature has relied on an initial structural simulation followed by the CFD simulation [22,23,25,26]. For example, it could, at most, utilize low-resolution clinical imaging for validation of the PVL location.…”

“…The link between thrombosis in TAVR and PVL was initially investigated in several in silico computational fluid dynamics (CFD) simulations [22][23][24][25]. PVL has been replicated with a patient-specific in vitro flow model, giving the ability for further in-depth study of the clinical scenarios for device comparison [26][27][28]. The in silico models have relied on initial structural finite element simulations to estimate deployment of the TAVR device in the patient anatomy, and the resulting PVL channels could only be compared to echo/Doppler imaging which is limited in resolution and accuracy of flow velocity [23,24,26].…”

“…PVL has been replicated with a patient-specific in vitro flow model, giving the ability for further in-depth study of the clinical scenarios for device comparison [26][27][28]. The in silico models have relied on initial structural finite element simulations to estimate deployment of the TAVR device in the patient anatomy, and the resulting PVL channels could only be compared to echo/Doppler imaging which is limited in resolution and accuracy of flow velocity [23,24,26]. These studies have utilized device thrombogenic emulation (DTE) methodology in which a particle model is used to estimate platelet trajectories, and stress accumulation along the trajectory is collapsed into a probability of device thrombogenicity or the device thrombogenic footprint [29][30][31][32].…”

Effect of Sinotubular Junction Size on TAVR Leaflet Thrombosis: A Fluid-structure Interaction Analysis

“…Commissural alignment was ensured during the deployment process. Detailed information on the TAVR crimping and deployment simulations can be found in our previous studies [22, 33, 34, 48]. Subsequently, the resultant geometries of the deployed systems were exported as STLs, which were in turn used to construct the boundary and volume meshes with ANSA BETA CAE [49], with dimensions specified in Table 1.…”