CLOSE RELATION OF ENDOTHELIAL FUNCTION IN THE HUMAN CORONARY AND PERIPHERAL CIRCULATIONS

Objectives. The relation between endothelium-dependent vasodilator fun ction in the brachial and coronary arteries was determined in the same subjects. Background. Coronary artery endothelial dysfunction precede s the development of overt atherosclerosis and is important in its pat hogenesis. A noninvasive assessment of endothelial function in a perip heral conduit vessel, the brachial artery, nas recently described, but the relation between brachial artery function and coronary artery vas odilator function has not been explored. Methods. In 50 patients refer red to the catheterization laboratory for the evaluation of coronary a rtery disease (mean age +/- SD 56 +/- 10 years), the coronary vasomoto r response to serial intracoronary infusions of the endothelium-depend ent agonist acetylcholine (10(-8) to 10(-6) mol/liter), was studied. E ndothelium-dependent vasodilation was also assessed in the brachial ar tery by measuring the change in brachial artery diameter in response t o reactive hyperemia. Results. Patients with coronary artery endotheli al dysfunction manifested as vasoconstriction in response to acetylcho line had significantly impaired flow-mediated vasodilation in the brac hial artery compared with that of patients,vith normal coronary endoth elial fuuction (4.8 +/- 5.5% vs. 10.8 +/- 7.6%, p < 0.01). Patients,vi th coronary artery disease also had an attenuated brachial artery vaso dilator response compared with that of patients with angiographically smooth coronary arteries (4.5 +/- 4.6% vs. 9.7 +/- 8.1%, p < 0.02). By multivariate analysis, the strongest predictors of reduced brachial d ilator responses to flow were baseline brachial artery diameter (p < 0 .001), coronary endotheIial dysfunction (p = 0.003), the presence of c oronary artery disease (p = 0.007) and cigarette smoking (p = 0.016). The brachial artery vasodilator response to sublingual nitroglycerin w as independent of coronary endothelial responses or the presence of co ronary artery disease. The positive predictive value of abnormal brach ial dilation (<3%) in predicting coronary endothelial dysfunction is 9 5%. Conclusions. This study demonstrated a close relation between coro nary artery endothelium-dependent vasomotor responses to acetylcholine and how-mediated vasodilation in the brachial artery, This noninvasiv e method may become a useful surrogate in assessing the predisposition to atherosclerosis in patients with cardiac risk factors.