The relationship between dipper/nondipper pattern and cardioankle vascular index in hypertensive diabetic patients

Abstract

24-h ambulatory blood pressure monitoring (24-h ABPM) is a better predictor of cardiovascular events (CVEs) than spot blood pressure (BP) measurements in hypertensive diabetic patients. In this patient group, the underlying mechanism of the relationship between a nondipper pattern determined with 24-h ABPM and increased incidence of CVE is unknown. Cardioankle vascular index (CAVI) is a new index of the overall arterial stiffness from the aorta to the ankle. The objective of the present study was to evaluate the relationship between a dipper/nondipper pattern and arterial stiffness in hypertensive diabetic patients using the CAVI method. We enrolled 99 hypertensive patients with type-2 diabetes mellitus. 24-h ABPM and CAVI measurements were performed for all patients. The relationship between a dipper/nondipper pattern and CAVI measurements was analyzed. Sixty-three (63.6%) patients had a nondipper pattern. In univariate analysis, CAVI, mean arterial pressure (MAP)-asleep, overall diastolic BP, overall systolic BP, duration of hypertension, and statin use were significantly higher among patients with a nondipper pattern than that in dippers. Multivariate linear regression analyses showed that the difference between MAP-asleep and MAP-awake was associated independently with CAVI (β coefficient=0.514, P<0.001). CAVI was correlated negatively with the nocturnal decrease in MAP (%) (r=-0.558 and P<0.001). The nondipper pattern determined with 24-h ABPM in hypertensive diabetic patients is associated with an increase in arterial stiffness. This patient group should be monitored closely for CVEs.