Arterial distensibility and circadian blood pressure variability

OBJECTIVE: To analyse the relationships between arterial distensibility and blood pressure level and its circadian variability assessed by non-invasive ambulatory blood pressure monitoring. DESIGN: One hundred and six patients (69 men, 37 women; aged 20-72 years) without any cardiovascular complication or treatment underwent 24 h ambulatory blood pressure monitoring. Aortic distensibility was evaluated by carotid-femoral artery pulse-wave velocity measurements performed with a validated automatic device (Complior). RESULTS: The pulse-wave velocity correlated significantly with age (P < 0.001), systolic blood pressure (P < 0.01) and heart rate (P < 0.05). Subjects with higher pulse-wave velocities (above the median value) had higher ambulatory blood pressure and heart rate values, mainly during night-time, and present a smaller nocturnal fall both in systolic and in diastolic blood pressure than do those with lower pulse-wave velocities (below the median). The pulse-wave velocity was revealed to be an independent predictor of the nocturnal fall in systolic blood pressure (multiple r = 0.272, P < 0.02) whereas age and, to a lesser extent, mean 24 h diastolic blood pressure were independent predictors of the nocturnal fall in diastolic blood pressure (multiple r = 0.387, P < 0.001). CONCLUSION: Reductions in arterial distensibility are associated with increased blood pressure and heart rate levels whereas perturbations of the circadian blood pressure profile are associated with increased nocturnal values. The increased risk of end-organ damage and vascular events in the presence of higher nocturnal blood pressure values suggests that a study of arterial distensibility in the normal follow-up of hypertensive patients might be of benefit.