FLOW-INDUCED VASODILATION OF THE HUMAN BRACHIAL-ARTERY IS IMPAIRED INPATIENTS LESS-THAN-40 YEARS OF AGE WITH CORONARY-ARTERY DISEASE

zThe objective of this study was to determine whether abnormal flow-in duced endothelium-dependent vasodilation in the brachial artery identi fies young patients with coronary artery disease (CAD). High-resolutio n ultrasonography was used to measure vascular reactivity in a periphe ral conduit vessel, the brachial artery, in 14 young men with CAD and in 11 age-matched, healthy, merle volunteers, Endothelium-dependent va sodilation was determined by measuring the change in brachial artery d iameter during increases in flow induced by reactive hyperemia. Endoth elium-independent vasodilation was assessed by administration of subli ngual nitroglycerin. To ascertain whether flow-mediated vasodilation i n humans is mediated by endothelium-derived nitric oxide, brachial art ery diameter was measured during reactive hyperemia, before and during administration of the nitric oxide synthase antagonist N-G-monomethyl -L-arginine (L-NMMA). Brachial artery diameter was also measured durin g intraarterial infusion of acetylcholine and nitroprusside before and after administration of L-NMMA. Flow-induced vasodilation was less in patients with CAD than in healthy volunteers (1.3+/-1.1% vs 6.2+/-0.7 %, p <0.05). Nitroglycerin increased brachial artery diameter similarl y in each subject group (11.3+/-1.0% vs 15.8+/-1.2%, p=NS). L-NMMA inh ibited flow-mediated vasodilarion and the vasodilative response to ace tylcholine, but did not affect the response to nitroprusside. It is co ncluded that abnormal flow-induced endothelium-dependent vasodilation occurs in the brachial artery of young patients with CAD. (C) 1996 by Excerpta Medica, Inc.