Carotid Artery Revascularization Improves Cardiac Sympathetic Nerve Activity in Patients With Carotid Artery Stenosis.

Abstract

The carotid sinus baroreceptor reflex controls the neural regulation of blood pressure. Baroreceptor disorders due to carotid sinus atherosclerosis have detrimental cardiovascular effects. This study investigated the medium-term effects of carotid artery revascularization (CAR) on sympathetic and cardiac function and systemic blood pressure variability in patients with carotid artery stenosis. This study included 21 consecutive patients (median age 70 years, 18 men) with carotid artery stenosis scheduled for CAR. 123I metaiodobenzylguanidine (MIBG) scintigraphy, echocardiography, brain natriuretic peptide levels, 24-h Holter electrocardiography (ECG), and ambulatory blood pressure monitoring assessed approximately 3 months postoperatively were compared to preoperative data. All 21 enrolled patients underwent CAR. Carotid artery stenting was done in three patients with cardiovascular risk or anatomical difficult for carotid endarterectomy. The mean common carotid artery end-diastolic velocity improved significantly (P < 0.01) by 1.6-fold, from 10.8 ± 3.2 to 16.1 ± 7.1 cm/s. In 123I-MIBG scintigraphy, the heart-to-mediastinum (H/M) count ratio was significantly higher than preoperatively (from 2.66 ± 0.48 to 2.86 ± 0.56, P = 0.03). Holter ECG analysis revealed a significant decrease in the low-frequency/high-frequency (LF/HF) ratio compared to preoperatively (from 2.17 ± 1.20 to 1.62 ± 0.68, P = 0.04). These findings suggest decreased myocardial sympathetic activation. In echocardiography, the tissue Doppler-derived e' increased, and E/e' decreased significantly (P < 0.05) from 11.7 ± 5.1 to 10.1 ± 4.0, suggesting an improved left ventricular diastolic capacity. The mean 24-h and nighttime blood pressures were unchanged. CAR in patients with carotid stenosis may provide medium-term improvement in cardiac sympathetic nerve activity and left ventricular diastolic dysfunction.