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

Area of Science:

• Cardiology
• Vascular Biology
• Hypertension Research

Background:

• Resistant hypertension (RHTN) encompasses patients with uncontrolled blood pressure (BP) on multiple medications (uncontrolled RHTN - UCRH) and those controlled on four or more drugs (controlled RHTN - CRH).
• The differences in endothelial function and circadian BP patterns between UCRH and CRH patient groups remain largely unknown.
• Understanding these distinctions is crucial for stratifying cardiovascular risk within RHTN populations.

Purpose of the Study:

• To investigate and compare circadian BP patterns and vascular endothelial function in patients with UCRH and CRH.
• To identify potential differences in endothelial-dependent and independent vasodilation between these RHTN subgroups.
• To explore whether these physiological differences correlate with varying cardiovascular risk.

Main Methods:

• Ambulatory BP monitoring was used to assess circadian BP patterns, including nocturnal dipping of systolic BP (SBP) and diastolic BP (DBP).
• Vascular function was evaluated by measuring brachial artery responses to endothelial-dependent (flow-mediated dilation - FMD) and endothelial-independent (nitroglycerin-mediated) stimuli.
• Biochemical testing was performed on 40 CRH patients, 26 UCRH patients, and 25 normotensive controls.

Main Results:

• The nighttime BP drop was significantly less pronounced in UCRH patients compared to CRH patients (SBP: 1.9% vs. 4.9%; DBP: 7.5% vs. 10.9%).
• Endothelial-dependent flow-mediated dilation (FMD) was significantly impaired in UCRH patients (5.9%) compared to CRH patients (7.1%).
• Normotensive controls exhibited better FMD than both RHTN groups, and RHTN patients generally showed impaired vascular function compared to controls.

Conclusions:

• Uncontrolled RHTN patients exhibit diminished nocturnal blood pressure dipping and more severe endothelial dysfunction compared to controlled RHTN patients.
• These findings highlight significant physiological differences between UCRH and CRH subgroups.
• Identifying these distinct RHTN subgroups may aid in better risk stratification and personalized management strategies for patients with resistant hypertension.