Transcatheter aortic valve implantation improves endothelial and autonomic function

Type of funding sources: None.

Degenerative aortic stenosis is the leading native valve pathology in developed countries. Its degeneration process is affected by aging, common cardiovascular risk factors and an atherosclerotic-like process preceded by endothelial and autonomic dysfunction. With the increasing integration of transcatheter aortic valve implantation (TAVI) in the treatment of aortic stenosis in the elderly, research is being intensively oriented into its beneficial effect on the cardiovascular system. Measurements of vascular function with flow mediated dilatation (FMD) and autonomic cardiac function using heart rate variability parameters represent a validated method for treatment evaluation at different time-points.

The purpose of our study was to assess whether haemodynamic and structural changes after TAVI will have a positive impact on endothelial and autonomic cardiac function on early and late follow-up.

50 patients with severe aortic stenosis destinated to TAVI were prospectively included. Data was collected at baseline (24 hours before the procedure), on early follow-up (48 hours after the procedure) and on late follow-up (6 months after the procedure). While different heart rate variability parameters were obtained using a high-resolution electrocardiogram, FMD was assessed using a standardized ultrasound-based process with induced forearm hyperaemia.

43 patients completed the study (mean age 81 (75-85); 60% women). FMD measurements significantly changed from baseline to early follow-up (2.8 ± 1.5 % to 4.7 ± 2.7 %, p < 0.001). Improvement was persistent on late follow up (4.8 ± 2.7 %, p = 0.936). Moreover, heart rate variability parameters remained unchanged on early follow-up and improved 6 months after. Late follow-up statistical significance was reached by HF, a frequency-domain parameter (5231 ± 1783 to 6507 ± 1789 ms2; p = 0.029) and two Poincare diagram parameters: RR ecc (682 to 906 ms2; p < 0.001) and SDRR (9.6 to 23.9 ms; p = 0.001). Significant predictors of FMD change were as following: 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) and NT-proBNP (R = 0.491; p = 0.001).

Both endothelial and autonomic function improved after TAVI. While FMD seems to change early due to acute haemodynamic changes attributed to aortic valve stenosis resolution, autonomic cardiac functions remain stable and ameliorate late after procedure, likely reflecting left ventricular reverse remodelling.