Patient-specific simulation of transcatheter aortic valve replacement: impact of deployment options on paravalvular leakage

Abstract

Transcatheter aortic valve replacement (TAVR) has emerged as an effective alternative to conventional surgical valve replacement in high-risk patients afflicted by severe aortic stenosis. Despite newer-generation devices enhancements, post-procedural complications such as paravalvular leakage (PVL) and related thromboembolic events have been hindering TAVR expansion into lower-risk patients. Computational methods can be used to build and simulate patient-specific deployment of transcatheter aortic valves (TAVs) and help predict the occurrence and degree of PVL. In this study finite element analysis and computational fluid dynamics were used to investigate the influence of procedural parameters on post-deployment hemodynamics on three retrospective clinical cases affected by PVL. Specifically, TAV implantation depth and balloon inflation volume effects on stent anchorage, degree of paravalvular regurgitation and thrombogenic potential were analyzed for cases in which Edwards SAPIEN and Medtronic CoreValve were employed. CFD results were in good agreement with corresponding echocardiography data measured in patients in terms of the PVL jets locations and overall PVL degree. Furthermore, parametric analyses demonstrated that positioning and balloon over-expansion may have a direct impact on the post-deployment TAVR performance, achieving as high as 47% in PVL volume reduction. While the model predicted very well clinical data, further validation on a larger cohort of patients is needed to verify the level of the model’s predictions in various patient-specific conditions. This study demonstrated that rigorous and realistic patient-specific numerical models could potentially serve as a valuable tool to assist physicians in pre-operative TAVR planning and TAV selection to ultimately reduce the risk of clinical complications.

Pre-Operative Modeling of Transcatheter Mitral Valve Replacement in a Surgical Heart Valve Bioprosthesis

“…These assumptions can influence the resulting Von Mises stress distribution of the S3 device, although this study was mainly focused on the deformed shape of the deployed S3 THV rather than the resulting stress distribution. Although stress distributions at the mitral valve annulus were in agreement with those reported for the simulation of the transcatheter aortic valve implantation by our group [15] and those of other groups [20,25,[26][27][28][29], the heart and mitral valve annulus structure is complex and characterized by a heterogeneous, hyperplastic, and anisotropic material with limited knowledge of material descriptors and constitutive behavior. Figure 4A shows the deformed shape of TMVR as deployed on the bioprosthetic heart valve after numerical simulation.…”

Simulation of left ventricular outflow tract (LVOT) obstruction in transcatheter mitral valve-in-ring replacement

“…Most of computational studies on THV are related to transcatheter aortic valve implantation to determine the biomechanical interaction of the device with stenotic valve leaflets [23,24] as well as the assessment of the risk of paravalvular leakage [25,26]. In TMVR, Kohli and collaborators [27] performed a fluid-dynamic analysis where the prolonged THV was simulated by a rigid wall protrusion in the left ventricle and observed an increase in the flow velocity and pressure drop across the neoLVOT as here observed. Similarly, De Vecchi et al [28] developed a parametric model of the protruded THV wall in the left ventricle and carried out several computational fluid-dynamic analyses for different degrees of LVOT obstruction.…”

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

“…These three-dimensional models were solved using A baqus E xplicit (Simulia, Dassault Systèmes) while considering only the stents of the TAVI devices. To calculate the position of the cuff and leaflets of each TAVI device, nodal displacement boundary conditions were applied to the stents of the deployed configurations with a linear elastic behaviour [ 34 , 35 ]. The leaflets position after the SAPIEN ViV implantation resembles its zero stressed configuration.…”