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 1.5% before TAVI to 4.7
2.7% early after TAVI (p 0.001) and was later maintained on
late follow-up (4.8 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 1783 to 6507 1789
ms; 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 ms; 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.