Response of coronary arteries to intracoronary acetylcholine infusion in patients with familial hypercholesterolemia]

Loss of the vasodilator response to acetylcholine (Ach), an endothelium-dependent vasodilator, has been demonstrated in animal models of atherosclerosis and in atherosclerotic coronary arteries of humans studied in vitro. The response of normal coronary arteries on angiograms to the intracoronary injection of Ach in patients with familial hypercholesterolemia (FH) was studied. Ten patients with FH (mean age, 53.6 +/- 6.5 years) with a mean serum total cholesterol of 334.8 mg/dl and 12 controls (mean age, 55.8 +/- 14.5 years) with a total cholesterol level of 183.6 mg/dl, and with normal coronary arteries on angiograms were studied. Patients with clinical histories suggestive of coronary spastic angina were excluded from this study. A bolus of 20, 50 micrograms Ach and 2 mg isosorbide dinitrate (ISDN) were infused into the left coronary artery in each subject. Changes in coronary diameters were measured after each injection with a videodensitometric analysis system. In the control group, the diameter at the middle segments of the left anterior descending artery (LAD) and at the proximal and middle segments of the left circumflex artery (LCX) increased significantly in response to Ach; whereas, in the FH group the diameter at the proximal segments of the LAD decreased significantly. There were significant differences in the coronary diameter changes in response to 50 micrograms Ach at the proximal and middle segments of the LAD and the LCX between the 2 groups. In contrast, between these 2 groups, there were no significant differences in the vasodilator responses to ISDN, a direct vascular smooth muscle dilator. The vasodilator response of coronary artery to Ach was diminished in patients with FH.