Acetylcholine-induced coronary vasoconstriction in young, heavy smokers with normal coronary arteriographic findings

Cigarette smoking is a major coronary risk factor. Acetylcholine dilates coronary arteries in normal subjects, but acetylcholine-induced coronary constriction has been reported in patients with normal coronary arteriographic findings and other risk factors for coronary artery disease. The purpose of the present study was to evaluate the epicardial coronary artery response to acetylcholine in young, heavy smokers.

Responses to stepwise infusion of acetylcholine (10(-8)M, 10(-7)M, 10(-6)M, and 10(-5)M) into the left coronary artery were studied in five young, heavy smokers and in five age-matched nonsmokers. All subjects were normotensive and had normal left ventricular function and coronary arteriographic findings. Levels of serum cholesterol, triglycerides, and low-density lipoprotein levels were within normal ranges. Vessel dimensions were measured on four different segments in each subject, with quantitative digital-substracted arteriography.

In smokers, no change was produced at the 10(-8) M and 10(-7) M concentrations of acetylcholine, but progressive diameter reduction was observed at 10(-6) M and 10(-5) M acetylcholine (-26.6% +/- 13.6%, p < 0.001; -42.2% +/- 9.5%, p < 0.001, respectively). In nonsmokers, a progressive diameter dilation was produced from 10(-8) M to 10(-6) M acetylcholine (+5.3% +/- 3.6%, p < 0.001; +12.4% +/- 6.5%, p < 0.001; +15.9% +/- 6.9%, p < 0.001, respectively), and no change was observed at 10(-5) M acetylcholine. In the two groups, all segments dilated after infusion of intracoronary isosorbide dinitrate.

The abnormal coronary vasoconstriction induced by acetylcholine in young, heavy smokers with angiographically normal coronary arteries suggests an endothelial vasodilator dysfunction. This mechanism may contribute to the pathogenesis of coronary artery disease in cigarette smokers.