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

Salvatore Pasta,Caterina Gandolfo

doi:10.3390/prosthesis2010004

Abstract

Obstruction of the left ventricular outflow tract (LVOT) is a common complication of transcatheter mitral valve replacement (TMVR). This procedure can determine an elongation of an LVOT (namely, the neo-LVOT), ultimately portending hemodynamic impairment and patient death. This study aimed to understand the biomechanical implications of LVOT obstruction in a patient who underwent TMVR using a transcatheter heart valve (THV) to repair a failed bioprosthetic heart valve. We first reconstructed the heart anatomy and the bioprosthetic heart valve to virtually implant a computer-aided-design (CAD) model of THV and evaluate the neo-LVOT area. A numerical simulation of THV deployment was then developed to assess the anchorage of the THV to the bioprosthetic heart valve as well as the resulting Von Mises stress at the mitral annulus and the contract pressure among implanted bioprostheses. Quantification of neo-LVOT and THV deployment may facilitate more accurate predictions of the LVOT obstruction in TMVR and help clinicians in the optimal choice of the THV size.

Highlights

The evolution of catheter-based structural interventions has given patients less invasive alternatives to surgery; the current generation of transcatheter heart valves (THV) is not designed for mitral position implantation and has an intrinsic geometry that may make mitral implantation suboptimal [1,2]
A numerical simulation of THV deployment was developed to assess the anchorage of the THV to the bioprosthetic heart valve as well as the resulting Von Mises stress at the mitral annulus and the contract pressure among implanted bioprostheses
We found that the area of the neo-left ventricular outflow tract (LVOT) is about 271 mm2, and this value is quite higher than current clinical guidelines for transcatheter mitral valve replacement (TMVR)

Summary

Introduction

The evolution of catheter-based structural interventions has given patients less invasive alternatives to surgery; the current generation of transcatheter heart valves (THV) is not designed for mitral position implantation and has an intrinsic geometry that may make mitral implantation suboptimal [1,2]. One of the main problems of TMVR for a valve-in-valve procedure is the obstruction of the left ventricular outflow tract (LVOT) [5]. A small outflow tract geometry will create a region of turbulent flow distal to the narrowing, causing a large drop in pressure beneath the aortic valve and determining sub-aortic stenosis when the residual LVOT cross-sectional area, known as neo-LVOT, is about 185 mm2 [6]. The main consequence of LVOT obstruction is the presence of complications for the patients that require further intervention or another therapeutic strategy

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Conclusion