Jl. Houghton et al., CORONARY VASOMOTOR REACTIVITY AMONG NORMOTENSIVE AFRICAN AND WHITE AMERICAN SUBJECTS WITH CHEST PAIN, The American journal of medicine, 102(3), 1997, pp. 245-251
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.