Non-dipping pattern relates to endothelial dysfunction in patients with uncontrolled resistant hypertension

Resistant hypertension (RHTN) includes both patients whose blood pressure (BP) is uncontrolled on three or more medications (uncontrolled RHTN (UCRH)) and patients whose BP is controlled with use of four or more drugs (controlled RHTN (CRH)). It is unknown whether endothelial function and nocturnal drop demonstrate a similar pattern in patients with CRH and UCRH. We examined circadian BP patterns and vascular function in these patients. In all, 40 CRH and 26 UCRH patients, and 25 normotensives underwent biochemical testing, ambulatory BP monitoring, determination of brachial artery responses to endothelial-dependent (flow-mediated; dilation (FMD)) and independent (nitroglycerin mediated) stimuli. The nighttime drop in systolic BP (SBP) and diastolic BP (DBP) was less pronounced in UCRH than in CRH (SBP, 1.9±1.6 versus 4.9±1.7%; DBP, 7.5±1.8 versus 10.9±1.8%, UCRH and CRH, respectively; P<0.05). FMD was greater in control group compared with RHTN patients. Patients with UCRH had significantly impaired FMD compared with CRH (5.9±2.3% versus 7.1±5.1%; P<0.0001). Therefore, UCRH patients have less nocturnal dipping and a more impaired endothelial response compared with CRH patients. These findings suggest that important differences among patients with RHTN may allow identify subgroups with increased cardiovascular risk.