A blunted decrease in nocturnal blood pressure is independently associated with increased aortic stiffness in patients with resistant hypertension.

Increased arterial stiffness may be causally related to resistant hypertension. Our objective was to investigate the variables, particularly those derived from ambulatory blood pressure (BP) monitoring (ABPM), associated with increased aortic stiffness in resistant hypertensives. In a cross-sectional study, 600 resistant hypertensive patients without peripheral arterial disease were evaluated. Arterial stiffness was assessed by aortic pulse wave velocity (PWV), and was considered increased if >12 m s(-1). Statistical analyses included multiple linear and logistic regressions to assess the independent correlates of increased aortic stiffness. One hundred and sixty-eight patients (28%) had aortic PWV >12 m s(-1). Patients with increased PWV were older and had a higher prevalence of cardiovascular risk factors than did those patients with low PWV. On ABPM, patients with elevated PWV had higher daytime and night time systolic BP (SBP) and pulse pressures (PP), less nocturnal decrease in SBP and a higher prevalence of non-dipping pattern. On multiple linear regression, the independently associated variables with aortic PWV were age (P<0.001), 24-h PP (P<0.001), high-density lipoprotein (HDL)-cholesterol (P<0.001), microalbuminuria (P<0.001), fasting glycemia (P=0.001) and a decrease in nocturnal SBP (P=0.002). Multivariate logistic regression confirmed these results, with the non-dipping patients having a 72% higher likelihood of presenting with increased aortic stiffness (95% confidence interval: 1.12-2.65, P=0.013). This association was observed in both the reduced and reverted dipping patterns, but not in the extreme dipping pattern. In conclusion, a blunted nocturnal decrease in BP is independently associated with increased aortic stiffness in resistant hypertensive patients. Other independent correlates are older age, diabetes, microalbuminuria, low HDL-cholesterol and a widened 24-h PP.