Effect of Systolic Blood Pressure and Carotid Stiffness on Baroreflex Gain in Elderly Subjects

BACKGROUND Aging is associated with diminished baroreflex sensitivity (gain), which predisposes elderly people to orthostatic hypotension, syncope, and cardiovascular morbidity. Aging is also associated with systolic blood pressure (SBP) elevation and carotid artery stiffness, which may both affect baroreflex gain. METHODS We examined the relation between SBP, carotid artery stiffness, and baroreflex gain in 34 healthy elderly (71 +/- 4 years) and 10 healthy young (31 +/- 3 years) subjects. SBP (Finapres) and carotid artery stiffness (ultrasound measures of relative carotid artery diameter changes during each blood pressure pulse) were measured. The gain of the transfer function relating the R-R interval to SBP fluctuations at a frequency of 0.05-0.15 Hz was used to assess cardiovagal baroreflex gain. RESULTS Elderly subjects had higher carotid artery stiffness (14.2 +/- 5.1 vs 6.6 +/- 1.8, p