Autonomic activity and baroreflex sensitivity in patients submitted to carotid stenting

Arterial baroreflex and cardiac autonomic control play important roles in hemodynamic instability after carotid artery stenting (CAS). Spontaneous baroreflex sensitivity (BRS), heart rate variability (HRV) and blood pressure variability (BPV) are established tools for the assessment of arterial baroreflex and cardiac autonomic activity. Aim of the study was to evaluate cardiac autonomic activity (by means of HRV, BPV and BRS) after CAS and to explore the impact of internal carotid artery stenosis on BRS changes after CAS. 37 patients (68±10.45 years) with internal carotid stenosis underwent CAS. HRV, BPV and BRS were measured in all subjects before and at 1 and 72h after CAS. ANOVA was performed to compare BRS, HRV and BPV parameters before and after CAS. Spearman analysis was performed to determine a possible correlation between carotid stenosis degree (or carotid plaque diameter) and BRS changes (ΔBRS). LF/HF (index of sympatho-vagal balance) decreased during postoperative period, in comparison with baseline (2.32±1.70 vs 1.65±1.40, p<0.05). There was a significant negative correlation between carotid stenosis degree and ΔBRS (r=-0.35, p=0.03) and between carotid plaques thickness and ΔBRS (r=-0.36, p=0.02). CAS procedure may cause an alteration of carotid wall mechanical properties, increasing baroreflex sensitivity. BRS does not increase in all the patients, because arterial wall damage and nerve destruction determined by atherosclerotic plaque may reduce ΔBRS.