Early impairment of acetylcholine-induced endothelium-dependent coronary vasodilation is not predictive of secondary graft atherosclerosis.

Abstract

STUDY OBJECTIVE: To test the hypothesis that the magnitude of early constriction of coronary arteries to acetylcholine might be a useful predictor of secondary graft atherosclerosis. DESIGN: The responses of epicardial coronary arteries to stepwise intracoronary infusion of acetylcholine (10(-8)M to 10(-5)M) were compared in 7 control subjects and in 18 patients who had undergone transplants within 2 months after surgery. MEASUREMENTS AND RESULTS: Vessel dimensions (percent basal diameter) were measured by quantitative angiography. Follow-up at 1 year showed angiographically normal coronary arteries in 12 patients (group 1) and coronary atherosclerosis in 6 patients (group 2). In control subjects, acetylcholine induced a dose-dependent dilation from 10(-8)M to 10(-6)M. No significant variation was observed at 10(-5)M. In patients with transplants early after surgery, diameters did not vary significantly from base at 10(-8)M in either group and constricted significantly at higher concentrations. Vasodilator responses to intracoronary isosorbide dinitrate were similar in both groups with transplants early after surgery, and at 1 year in group 1, but significantly lower than in control subjects. CONCLUSIONS: In patients who had undergone transplants, acetylcholine-induced endothelium-dependent coronary artery dilation is similarly impaired early after surgery (within 2 months) in patients with and without coronary atherosclerosis at 1-year follow-up. Thus, response to acetylcholine is not a predictor of secondary atherosclerosis in patients with heart transplants.