title: Hemodynamics and Vascular Hypertrophy in African Americans and Caucasians With High Blood Pressure.
abstract: Hypertension in African Americans is characterized by greater systemic vascular resistance (SVR) compared with Caucasian Americans, but the responsible mechanisms are not known. The present study sought to determine if peripheral vascular hypertrophy is a potential mechanism contributing to elevated SVR in African Americans with high blood pressure (BP).
  
  
  
  In a biracial sample of 80 men and women between the ages of 25 and 45 years, with clinic BP in the range 130/85-160/99mm Hg, we assessed cardiac output and SVR, in addition to BP. Minimum forearm vascular resistance (MFVR), a marker of vascular hypertrophy, also was assessed.
  
  
  
  SVR was elevated in African Americans compared with Caucasians (P < 0.001). Regression models indicated that age, body mass index, 24-hour diastolic BP, and ethnicity were significant predictors of SVR. There was also a significant interaction between ethnicity and MFVR in explaining SVR in the study sample. In particular, there was a significant positive association between MFVR and SVR among African Americans (P = 0.002), whereas the association was inverse and not statistically significant among Caucasians (P = 0.601).
  
  
  
  Hypertrophy of the systemic microvasculature may contribute to the elevated SVR that is characteristic of the early stages of hypertension in African American compared with Caucasians.
authors.affiliation: Department of Psychiatry and Behavioral Sciences Medicine, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: LaBarron K
authors.initials: LK
authors.lastname: Hill
authors.affiliation: Department of Psychiatry and Behavioral Sciences Medicine, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Sherwood
authors.affiliation: Department of Psychiatry and Behavioral Sciences Medicine, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: James A
authors.initials: JA
authors.lastname: Blumenthal
authors.affiliation: Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA.
authors.forename: Alan L
authors.initials: AL
authors.lastname: Hinderliter
mesh_terms: D000328:Adult; D001741:Black or African American; D001794:Blood Pressure; D001808:Blood Vessels / Q000473:pathology* / Q000503:physiopathology*; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D005260:Female; D005542:Forearm / Q000098:blood supply*; D054624:Health Status Disparities; D006801:Humans; D006973:Hypertension / Q000208:ethnology / Q000473:pathology* / Q000503:physiopathology*; D006984:Hypertrophy; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D015999:Multivariate Analysis; D009657:North Carolina / Q000453:epidemiology; D012307:Risk Factors; D066253:Vascular Remodeling; D014655:Vascular Resistance; D044465:White People
keywords: blood pressure; ethnicity; hypertension; hypertrophy; vascular resistance.