Journal Article

Population-specific material properties of the implantation site for transcatheter aortic valve replacement finite element simulations

Delahunty, Nicola, Bosi, Giorgia M., Cheang, Mun Hong, Taylor, Andrew M., Mullen, Michael, Schievano, Silvia, Capelli, Claudio

2018

Overview

Patient-specific computational models are an established tool to support device development and test under clinically relevant boundary conditions. Potentially, such models could be used to aid the clinical decision-making process for percutaneous valve selection; however, their adoption in clinical practice is still limited to individual cases. To be fully informative, they should include patient-specific data on both anatomy and mechanics of the implantation site. In this work, fourteen patient-specific computational models for transcatheter aortic valve replacement (TAVR) with balloon-expandable Sapien XT devices were retrospectively developed to tune the material parameters of the implantation site mechanical model for the average TAVR population. Pre-procedural computed tomography (CT) images were post-processed to create the 3D patient-specific anatomy of the implantation site. Balloon valvuloplasty and device deployment were simulated with finite element (FE) analysis. Valve leaflets and aortic root were modelled as linear elastic materials, while calcification as elastoplastic. Material properties were initially selected from literature; then, a statistical analysis was designed to investigate the effect of each implantation site material parameter on the implanted stent diameter and thus identify the combination of material parameters for TAVR patients. These numerical models were validated against clinical data. The comparison between stent diameters measured from post-procedural fluoroscopy images and final computational results showed a mean difference of 2.5 ± 3.9%. Moreover, the numerical model detected the presence of paravalvular leakage (PVL) in 79% of cases, as assessed by post-TAVR echocardiographic examination. The final aim was to increase accuracy and reliability of such computational tools for prospective clinical applications.

• Publisher: Elsevier Ltd,Elsevier Limited,Elsevier Science
• Subject: Aged / Aged, 80 and over / Anatomy / Aortic valve / Aortic Valve - anatomy & histology / Aortic Valve - diagnostic imaging / Aortic Valve - surgery / Aortic Valve Insufficiency - diagnostic imaging / Aortic Valve Insufficiency - surgery / Balloon treatment / Balloon Valvuloplasty / Biomechanics / Blood vessels / Calcification / Calcinosis - diagnostic imaging / Calcinosis - surgery / Computation / Computed tomography / Computer applications / Computer simulation / Decision making / Echocardiography / Elastic properties / Elastoplasticity / Female / Finite Element Analysis / Finite element method / Finite element modelling / Fluoroscopy / Heart Valve Prosthesis / Humans / Implantation / Implantation site mechanical response / Implants / Male / Mathematical models / Parameter identification / Parameters / Patient-Specific Modeling / Population (statistical) / Population-specific material parameters / Reproducibility of Results / Software / Statistical analysis / Stents / Surgical implants / Therapeutic applications / Tomography / Tomography, X-Ray Computed / Transcatheter aortic valve replacement / Transcatheter Aortic Valve Replacement - instrumentation / Transplants & implants / Valve leaflets