Comparison of Aortic Flow Patterns Before and After Transcatheter Aortic Valve Implantation

Abstract

Little is known of the likely changes in blood flow velocity profiles and aortic wall shear stress (WSS) following transcatheter aortic valve implantation (TAVI). The objective of this study was to investigate the effects of TAVI on flow patterns in the thoracic aorta by using cardiovascular magnetic resonance imaging (CMR) and computational fluid dynamics (CFD). An elderly patient with aortic stenosis was examined using MRI pre- and post-TAVI, and CFD simulations were carried out incorporating MRI-derived patient-specific anatomy and upstream flow conditions. Pre-TAVI velocity profiles demonstrated the highly disturbed turbulent flow and jet impacting the wall of the arch owing to the partial opening of the stenosed aortic valve, with likely pathological effects. In the Post-TAVI aorta, velocity profiles were similar to those of healthy aortas with spatially more uniform WSS and lower turbulence levels, demonstrating the favourable effects of the TAVI procedure in restoring normal aortic flow. This study has shown both the effectiveness of TAVI on an individual patient and the advantage of the combined CMR and CFD method for a comprehensive patient-specific assessment of pre- and post-TAVI aortic flow patterns and WSS over CMR alone.