Improved Endothelial and Autonomic Function after Transcatheter Aortic Valve Implantation

Background: Degenerative aortic stenosis is an atherosclerotic-like process associated with impaired endothelial and autonomic function. Transcatheter aortic valve implantation (TAVI) has become a treatment of choice for patient with severe degenerative aortic stenosis at high surgical risk. The effect of this procedure on endothelial function measured with flow mediated dilatation (FMD) and autonomic function measured with heart rate variability (HRV) at different time-points of disease management (early and late follow-up) remains unknown. Methods: We prospectively included 50 patients with severe aortic stenosis who were deemed suitable for TAVI by the Heart Team. FMD and HRV parameters were collected at baseline (<24 h pre-TAVI), at early follow-up (up to 48 h post-TAVI) and at late follow-up (3-6 months post-TAVI). Results: 43 patients (mean age 81 (75-85); 60% women) completed the study. FMD significantly improved from 2.8 & PLUSMN; 1.5% before TAVI to 4.7 & PLUSMN; 2.7% early after TAVI (p < 0.001) and was later maintained on late follow-up (4.8 & PLUSMN; 2.7%, p = 0.936). Conversely, high-resolution ECG parameters remained preserved at early and improved at late follow-up after TAVI. Significant improvement was detected in a high frequency-domain parameter-HF (from 5231 & PLUSMN; 1783 to 6507 & PLUSMN; 1789 ms2; p = 0.029) and in two Poincare plot parameters: ratio of the short-and long-term R-R variability in the Poincare plot-SD1/SD2 (from 0.682 to 0.884 ms2; p = 0.003) and short-term R-R variability in the Poincare plot-SDRR (from 9.6 to 23.9 ms; p = 0.001). Echocardiographic parameters comprising baseline maximal aortic valve velocity (R = 0.415; p = 0.011), mean aortic gradient (R = 0.373; p = 0.018), indexed stroke volume (R = 0.503; p = 0.006), change in aortic valve maximal velocity (R = 0.365; p = 0.031), change in mean aortic gradient (R = 0.394; p = 0.019) and NT-proBNP (R = 0.491; p = 0.001) were found as significant predictors of change in FMD. Conclusions: Endothelial function measured with FMD and autonomic function obtained with HRV parameters significantly improve after TAVI. While endothelial function improves early and is maintained later after TAVI, autonomic function remains stable and improves on late follow-up. This is most likely caused by early hemodynamic changes after resolution of aortic valve obstruction and gradual left ventricular remodeling. Clinical Trial Registration: www.clinicaltrials.gov, identifier NCT04286893.