Assessment of Wall Shear Stress on the Aortic Valve in Patients with Left Ventricular Assist Device Using Vector Flow Mapping

Abstract

Purpose De novo aortic insufficiency is one of unresolved complications after left ventricular assist device (LVAD) implant. It has been hypothesized that decreased and oscillatory wall shear stress (WSS) on the aortic valve following LVAD implantation cause leaflet degeneration resulting in AI. We developed novel approach to measure WSS on the aortic valve using vector flow mapping (VFM) images. Methods Aortic root color Doppler image was obtained using intraoperative epiaortic echocardiogram in 6 patients who received LVAD implant and 8 patients undergoing LVAD explant and heart transplant. As a control group, we enrolled 5 patients undergoing CABG surgery. Using obtained images, WSS and oscillatory shear index (OSI) on the right coronary cusp (RCC) was calculated with off-line software, Echo VFM® (Cardio Flow Design, Tokyo, Japan) (Figure). Results Image analysis was successful in all patients. The WSS on the ventricularis of the RCC was significantly lower in the LVAD group compared to control (0.09±0.06 vs. 0.35±0.27 Pa, p Conclusion Significantly lower WSS on the ventricularis may be accountable for AV degeneration and subsequent De Novo AI in patients with LVAD.