Effects of black race on forearm resistance vessel function.
Presentation, response to therapy, and clinical outcome in hypertension differ according to race, and these observations could relate to differences in microvascular function. We examined forearm microvascular function in age-matched black (n=56) and white subjects (n=62) using intra-arterial agonist infusion and venous occlusion plethysmography. In normotensive subjects (n=70; 34 black and 36 white normotensives), methacholine-, sodium nitroprusside-, and verapamil-induced vasodilation was equivalent in black and white subjects. In hypertensive subjects (n=48; 22 black and 26 white hypertensives), the vasodilator response to methacholine was markedly lower in black subjects compared with white subjects (P<0.001). The vasodilator responses to sodium nitroprusside and verapamil, however, were equivalent in black and white hypertensive subjects. Acute ascorbic acid infusion improved the methacholine response equally in black and white hypertensive patients, suggesting that a difference in a rapidly reversible form of oxidative stress does not explain these findings. Thus, the present study demonstrates important racial differences in vascular function and a marked impairment in endothelial vasomotor function in black patients with hypertension. Further studies will be required to elucidate the mechanisms and determine whether these insights will lead to more appropriately tailored management of hypertension and its complications.
Kahn
David F
DF
Evans Department of Medicine and Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Mass, USA.
Duffy
Stephen J
SJ
Tomasian
Douglas
D
Holbrook
Monika
M
Rescorl
Lynn
L
Russell
Judson
J
Gokce
Noyan
N
Loscalzo
Joseph
J
Vita
Joseph A
JA
D000328:Adult; D000704:Analysis of Variance; D000975:Antioxidants / Q000494:pharmacology; D001205:Ascorbic Acid / Q000494:pharmacology; D044383:Black People; D001916:Brachial Artery / Q000187:drug effects / Q000502:physiology; D016085:Bronchoconstrictor Agents / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D005542:Forearm / Q000098:blood supply*; D006801:Humans; D006973:Hypertension / Q000503:physiopathology; D008297:Male; D016210:Methacholine Chloride / Q000494:pharmacology; D008875:Middle Aged; D009599:Nitroprusside / Q000494:pharmacology; D012039:Regional Blood Flow / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology*; D014665:Vasodilator Agents / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology; D044465:White People
D000975:Antioxidants; D016085:Bronchoconstrictor Agents; D014665:Vasodilator Agents; D016210:Methacholine Chloride; D009599:Nitroprusside; D014700:Verapamil; D001205:Ascorbic Acid