Baroreflex sensitivity is impaired in bilateral carotid atherosclerosis

Background and Purpose - The arterial baroreflex is an important determinant of the short-term regulation of blood pressure and cardiovascular variability. The purpose of our study was to determine whether baroreflex sensitivity (BRS) and heart rate (HR) variability are altered in patients with carotid atherosclerosis (CA) and to assess the impact of characteristics of CA on BRS. Methods - BRS and HR variability were prospectively evaluated in 75 consecutive patients undergoing carotid duplex examination in our neurosonology unit. Resting BRS was measured with the sequence method. HR variability was evaluated using spectral analysis. Results - BRS was significantly reduced in patients with bilateral CA compared with patients without CA (P=0.015) and patients with unilateral CA (P=0.045). BRS was unaltered in patients with unilateral CA compared with patients with no CA. BRS was already reduced in mild (stenosis <50%), bilateral CA and was not further impaired in more severe CA. The association of BRS impairment with bilateral CA remained significant after adjustment for age, hypertension, and a history of stroke or transient ischemic attack. The study of HR variability demonstrated a reduction in the power of high-frequency band in patients with bilateral CA compared with patients with unilateral CA or without CA (P=0.015). Conclusion - Bilateral CA is associated with an impairment of BRS and a shift of the sympathovagal balance toward a relative decrease of the parasympathetic component of HR variability. These changes are already present in mild, bilateral CA.