Endothelial-dependent flow-mediated dilation in African Americans with masked-hypertension

Am J Hypertens. 2011 Oct;24(10):1102-7. doi: 10.1038/ajh.2011.103. Epub 2011 Jun 16.


Background: Office-blood pressure (BP) measurements alone overlook a significant number of individuals with masked-hypertension (office-BP: 120/80-139/89 mm Hg and 24-h ambulatory BP monitoring (ABPM) daytime ≥135/85 mm Hg or night-time ≥120/70 mm Hg). Diminished endothelial function contributes to the pathogenesis of hypertension. To better understand the pathophysiology involved in the increased cardiovascular (CV) disease risk associated with masked-hypertension, we estimated the occurrence, assessed the endothelial function, compared plasma levels of inflammatory markers, white blood cell count (WBC count), tumor necrosis factor-α (TNF-α), and high sensitivity C-reactive protein (hsCRP) and examined the possible relationship between endothelial function and inflammatory markers in apparently healthy prehypertensive (office-BP: 120/80-139/89 mm Hg) African Americans.

Methods: Fifty African Americans who were sedentary, nondiabetic, nonsmoking, devoid of CV disease were recruited. Office-BP was measured according to JNC-7 guidelines to identify prehypertensives in whom ABPM was then assessed. Fasting plasma samples were assayed for inflammatory markers. Brachial artery flow-mediated dilation (FMD) at rest and during reactive hyperemia was measured in a subset of prehypertensives.

Results: Subjects in the masked-hypertension sub-group had a higher hsCRP (P = 0.04) and diminished endothelial function (P = 0.03) compared to the true-prehypertensive sub-group (office-BP: 120/80-139/89 mm Hg and ABPM: daytime <135/85 mm Hg or night-time <120/70 mm Hg). Regression analysis showed that endothelial function was inversely related to hsCRP amongst the masked-hypertensive sub-group (R(2) = 0.160; P = 0.04).

Conclusions: Masked-hypertension was identified in 58% of African Americans which suggests that a masking phenomenon may exist in a sub-group of prehypertensives who also seem to have a diminished endothelial function that could be mediated by an elevated subclinical inflammation leading to the increased CV disease.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • African Americans
  • Aged
  • Blood Pressure Monitoring, Ambulatory
  • C-Reactive Protein / analysis
  • Endothelium, Vascular / physiology*
  • Female
  • Humans
  • Leukocyte Count
  • Male
  • Masked Hypertension / physiopathology*
  • Middle Aged
  • Nitric Oxide / physiology
  • Prehypertension / physiopathology
  • Regional Blood Flow
  • Vasodilation*


  • Nitric Oxide
  • C-Reactive Protein