CORONARY VASOMOTOR REACTIVITY AMONG NORMOTENSIVE AFRICAN AND WHITE AMERICAN SUBJECTS WITH CHEST PAIN

BACKGROUND AND OBJECTIVES: Excess cardiovascular morbidity and mortali ty among African (black) Americans is the subject of intensive investi gation but the etiology remains speculative. One hypothesis proposes t hat inherent, or intrinsic, differences in coronary vascular reactivit y and endothelial function predispose African Americans to enhanced va soconstriction and/or depressed vasodilation, resulting in excess isch emia, The objective of this study was to establish whether coronary va soreactivity differs among normotensive, nondiabetic African and white Americans with normal arteries referred for coronary arteriography be cause of chest pain. PATIENTS AND METHODS: Eleven African American (8 female, 3 male) and 28 white American (9 female, 19 male) normotensive , euglycemic patients with normal coronary arteries were prospectively recruited for invasive testing of coronary artery and microvascular r elaxation using the endothelium-dependent and independent agents, acet ylcholine and adenosine; a Doppler tipped intracoronary guidewire; and quantitative coronary angiography. RESULTS: The study cohort consiste d of 17 women (44%) and 22 men (56%) with a mean age of 46 +/- 10 yrs. Of 8 African American women, 6 were premenopausal and 2 were postmeno pausal on estrogen replacement therapy. Of 9 white American women, 2 w ere premenopausal, 1 was 46-years old with a previous history of hyste rectomy without ovariectomy, 2 were postmenopausal on estrogen replace ment therapy, 2 were perimenopausal and 44- and 54-years old, and 2 we re postmenopausal without estrogen replacement therapy. In response to maximal infusion of acetylcholine, epicardial coronary arteries and r esistance vessels dilated similarly in black and white subjects. Dose- response curves revealed no significant racial differences during subm aximal graded infusion of acetylcholine. In response to peak effect of adenosine, there were no racial differences in dilation of the microc irculation. CONCLUSIONS: In the absence of hypertension, diabetes mell itus, and angiographic evidence of coronary artery disease, African Am erican women demonstrate no evidence of intrinsic predisposition to en hanced coronary conduit vasoconstriction or depressed microcirculatory dilation in response to the endothelium-dependent and -independent va sodilator agonists-acetylcholine and adenosine--when compared with res ponses of similar white men and women. Because of low enrollment of bl ack males, definitive conclusions cannot be drawn regarding this group . (C) 1997 by Excerpta Medica, Inc.