The influence of baroreflex sensitivity on ambulatory arterial stiffness index in individuals with cardiovascular risk

OBJECTIVES: Although the predictor role of ambulatory arterial stiffness index (AASI) for cardiovascular risk has been shown, the question of whether AASI is a measure of arterial stiffness or, in fact, reflects influence of other origins on the arterial tree remains to be determined. We sought to elucidate whether AASI is associated with baroreflex sensitivity (BRS) or blood pressure (BP) reactivity to stress in individuals with cardiovascular risk. METHODS: A total of 120 participants were included in this study. Ambulatory BP measurements were performed over a 24-h period. AASI was calculated as 1 minus the regression slope of diastolic on systolic BP obtained from 24-h ambulatory BP monitoring data. BRS was estimated from the spontaneous changes in systolic BP and corresponding interbeat heart rate intervals. BP reactivity was induced by three stressors including the Stroop Color and Word Test, anger recall interview, and handgrip exercise. Arterial stiffness was determined by the pulse wave velocity. RESULTS: AASI significantly and inversely correlated to resting BRS (r=-0.24, P=0.01) and BRS under stress (r=-0.33, P=0.02) but not with systolic blood pressure reactivity (P=0.92) or pulse wave velocity (P=0.53). Adjusting for possible confounders, BRS independently predicted AASI (P=0.01). CONCLUSION: Increased AASI is associated with reduced BRS. Decreased BRS may at least in part explain the prognostic role of AASI in predicting cardiovascular risk. Our findings add support to the clinical significance of AASI. In particular, AASI may aid in the detection of cardiovascular risk.