Numerical Parametric Study of Paravalvular Leak Following a Transcatheter Aortic Valve Deployment Into a Patient-Specific Aortic Root

Abstract

Paravalvular leak (PVL) is a relatively frequent complication after transcatheter aortic valve replacement (TAVR) with increased mortality. Currently, there is no effective method to pre-operatively predict and prevent PVL. In this study, we developed a computational model to predict the severity of PVL after TAVR. Nonlinear finite element (FE) method was used to simulate a self-expandable CoreValve deployment into a patient-specific aortic root, specified with human material properties of aortic tissues. Subsequently, computational fluid dynamics (CFD) simulations were performed using the post-TAVR geometries from the FE simulation, and a parametric investigation of the impact of the transcatheter aortic valve (TAV) skirt shape, TAV orientation, and deployment height on PVL was conducted. The predicted PVL was in good agreement with the echocardiography data. Due to the scallop shape of CoreValve skirt, the difference of PVL due to TAV orientation can be as large as 40%. Although the stent thickness is small compared to the aortic annulus size, we found that inappropriate modeling of it can lead to an underestimation of PVL up to 10 ml/beat. Moreover, the deployment height could significantly alter the extent and the distribution of regurgitant jets, which results in a change of leaking volume up to 70%. Further investigation in a large cohort of patients is warranted to verify the accuracy of our model. This study demonstrated that a rigorously developed patient-specific computational model can provide useful insights into underlying mechanisms causing PVL and potentially assist in pre-operative planning for TAVR to minimize PVL.

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

“…In a more extensive work (De Jaegere et al 2016) modeling predictability was tested on a set of 60 cases of Medtronic CoreValve deployment and validated the results with angiography and echocardiography measurements; yet no description of the reconstruction of the patients anatomy and of the modeling assumptions was provided. Finally, a recent study (Mao et al 2018) investigated the effect of CoreValve orientation and modeling assumptions, such as skirt shape and stent thickness, on post-deployment hemodynamics. Post-TAVR thrombus formation was only considered for leaflets thrombosis after ViV.…”

On the Modeling of Patient-Specific Transcatheter Aortic Valve Replacement: A Fluid–Structure Interaction Approach

“…A high-fidelity model of the CoreValve Evolute R (Medtronic, Minneapolis, MN, USA) was created using the illustrations in the literature [53]; in particular, a complete parametric CAD model of the frame, leaflets, and skirt was realized by means of SolidWorks 2018 (Dassault Systèmes SolidWorks Corp., Waltham, MA, USA). For the metallic frame, a constant-diameter stent was obtained by replicating the elementary unit cell 15-times (Figure 1a).…”

“…The idealized approach aims at the investigation of numerical methodologies, technical aspects and specific clinical questions, with simplified models of complex structures [23,24,33,34,[25][26][27][28][29][30][31][32]. The patient-specific approach is characterized by the segmentation and reconstruction of the anatomical geometry from computed tomography (CT) or magnetic resonance imaging [17,35,[44][45][46][47][48][49][50][51][52][53]36,[54][55][56][37][38][39][40][41][42][43]. This approach is more labor-intensive and time-consuming as compared to the first one but in favor of a more realistic representation of the clinical situation.…”

“…CFD simulations give information on the pressure and velocity field within the fluid domain by solving the continuity and Navier-Stokes equations. PVL was numerically evaluated after FE deployment simulations with steady-state [45] or transient [53,57] CFD analyses. The variation of flow patterns in the aortic root-induced by transcatheter aortic valves [41] and the relation between valve thrombosis and reduced leaflets motion in case of TAVR [32] were investigated.…”

Fluid Structure Interaction on Paravalvular Leakage of Transcatheter Aortic Valve Implantation Related to Aortic Stenosis: A Patient-Specific Case

“…Consequently, this leads to unequal distribution of blood supply into the important organs of the body [28]. Another study by Mao et al [29] has developed a computational model predicting the severity of PVL after TAVI. In this study, FEA and CFD simulation were conducted separately.…”