title: Brachial vascular reactivity in blacks.
abstract: Endothelial function was studied ultrasonographically in a healthy subset of African Americans (blacks) because they have an increased risk of hypertension and vascular disease. Twenty-four healthy black and 28 well-matched white subjects were investigated. Ischemia was induced by inflating a cuff over the forearm to 40 mm Hg higher than systolic pressure for 5 minutes. Brachial artery diameter and blood flow velocity were measured at baseline and at 15, 45, and 60 seconds after deflation by use of an Acuson 128XP10 ultrasonograph with a 7.5 MHz transducer. Mean postischemic dilatation, an index of endothelial function, was 1.76+/-0.56% in blacks and 8.79+/-1.22% in whites (P<0.001). Median postischemic vasodilatation in black men [0% (0% to 2.86%)] was not significantly different to that in black women [0.82% (0% to 3.14%)], whereas white women [11.48% (8.70% to 14.29%)] dilated significantly more than white men [4.20% (2.13% to 5.56%)] (P<0.05). Both groups dilated significantly over baseline diameter to sublingual nitroglycerin administration 18.7+/-2.5% (blacks) and 20.2+/-3.2% (whites; P=NS). Mean hyperemic responses did not differ significantly between the 2 subject groups, nor did they differ between men and women of both ethnic groups. We conclude that endothelium-dependent vasodilatation is significantly impaired in healthy, young blacks compared with whites and that gender differences are not seen in blacks with regard to this phenomenon. An impairment in endothelium-dependent NO generation may be a contributing factor to future hypertension and vascular disease in healthy blacks.
authors.affiliation: Divisions of Endocrinology, State University of New York at Buffalo, USA.
authors.forename: D
authors.initials: D
authors.lastname: Perregaux
authors.forename: A
authors.initials: A
authors.lastname: Chaudhuri
authors.forename: S
authors.initials: S
authors.lastname: Rao
authors.forename: A
authors.initials: A
authors.lastname: Airen
authors.forename: M
authors.initials: M
authors.lastname: Wilson
authors.forename: B H
authors.initials: BH
authors.lastname: Sung
authors.forename: P
authors.initials: P
authors.lastname: Dandona
mesh_terms: D000328:Adult; D044383:Black People / Q000235:genetics*; D001783:Blood Flow Velocity / Q000502:physiology; D001916:Brachial Artery / Q000502:physiology*; D004730:Endothelium, Vascular / Q000502:physiology; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology / Q000235:genetics; D007511:Ischemia / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D014463:Ultrasonography; D014664:Vasodilation / Q000502:physiology; D044465:White People / Q000235:genetics; D001741:Black or African American