AHA/ACC-defined stage 1 hypertensive adults do not display cutaneous microvascular endothelial dysfunction

In 2017, the American Heart Association (AHA) and American College of Cardiology (ACC) redefined stage 1 hypertension to systolic blood pressure (BP) 130–139 mmHg or diastolic BP 80–89 mmHg; however, the degree to which microvascular endothelial dysfunction is evident in adults with stage 1 hypertension remains equivocal. We tested the hypotheses that cutaneous microvascular endothelial dysfunction would be present in adults with stage 1 hypertension (HTN1) compared with normotensive adults (NTN; BP <120/<80 mmHg) but would be less severe compared with adults with stage 2 hypertension (HTN2; systolic BP ≥140 mmHg or diastolic BP ≥90 mmHg) and that this graded impairment would be mediated by reductions in nitric oxide (NO)dependent dilation. This retrospective analysis included 20 NTN (5 men; 45–64 yr; BP 94–114/60–70 mmHg), 22 HTN1 (11 men; 40–74 yr; BP 110–134/70–88 mmHg), and 44 HTN2 (27 men; 40–74 yr; BP 128–180/80–110 mmHg). BP and nocturnal dipping status were also assessed using 24-h ambulatory BP monitoring. Red cell flux (laser Doppler flowmetry) was measured during intradermal microdialysis perfusion of acetylcholine (ACh; 10-¹⁰ to 10-¹M) alone and concurrently with the nonspecific nitric oxide (NO) synthase inhibitor N^G-nitro-L-arginine methyl ester (L-NAME; 15 mM). ACh-induced dilation was impaired in HTN2 (P < 0.01), but not in HTN1 (P = 0.85), compared with NTN. Furthermore, reductions in NO-dependent dilation were evident in HTN2 (P < 0.01) but not in HTN1 (P = 0.76). Regardless of BP, endothelium-dependent dilation was impaired in nondippers (nighttime drop in systolic BP <10%) compared with dippers (nighttime drop in systolic BP ≥10%, P < 0.05). In conclusion, functional impairments in NO-mediated endothelium-dependent dilation were not evident in HTN1. However, regardless of BP classification, the lack of a nocturnal dip in BP was associated with blunted endothelium-dependent dilation.