833 Haemodynamic Changes Post Aortic Valve Replacement Lead to Early Improvement in Endothelial Function: Results From the eFAST Study

Abstract

Severe aortic stenosis (AS) patients exhibit impaired coronary flow reserve (CFR), resulting in myocardial ischaemia in absence of obstructive coronary disease. Although endothelial dysfunction is known to contribute towards impaired CFR, it remains unknown whether endothelial function recovers following relief of AS. We therefore sought to assess the early and late changes in endothelial function following aortic valve replacement (AVR). Patients undergoing transcatheter or surgical AVR for severe AS had ultrasound assessment of endothelial-independent and -dependent flow mediated dilation (FMD). Measurements were performed prior to, 24hrs after and 28 days after intervention. Intraobserver FMD reproducibility was excellent (intraclass correlation coefficient 0.96, p<0.001). 30 patients were recruited (33% female), with twenty-seven (90%) undergoing transcatheter AVR. FMD significantly increased from 4.6±2.2% (pre-AVR) to 9.9±3.3% 24hrs post-procedure (p<0.0001). Repeat FMD at 28 days demonstrated that this improvement was sustained (8.7±1.9%, p<0.0001 compared with pre-AVR). Cumulative brachial WSS (represented as AUC) decreased progressively (3665±1810 vs 3228±1414 vs 2558±1101(dynxs)/cm2, p=0.001). In addition, the positive correlation between brachial WSS AUC and FMD was restored following AVR (r=0.05 pre-AVR vs r=0.52 at 28days). Our data shows that endothelial function in patients with AS improves within 24h after AVR and that this improvement is sustained. We hypothesise that this likely occurs as a result of improved arterial haemodynamics, leading to lower localised WSS and release of vasoactive mediators that may also alleviate myocardial ischaemia.