Effects of Vasodilators on Coronary Vasospasm Induced by Ergonovine Malate
Coronary vasospasm sometimes causes sudden cardiac death; evaluation of the effects of vasodilators would thus be of importance. Twenty patients (25 coronary arteries) with vasospastic angina were examined. Coronary vasodilators were withdrawn at least 48 h before the first coronary angiography (CAG) was performed. None of the patients had fixed stenosis of more than 50% of the coronary diameter. Total or subtotal occlusion of the coronary artery was induced in all patients by the intracoronary infusion of ergonovine malate (EM). On the 2nd day, 40 mg of long-acting isosorbide dinitrate (ISDN) was administrated at 1:00 a.m. and CAG was performed at 8:00 a.m. On the 3rd day, 20 mg of nifedipine, and on the 4th day, 60 mg of diltiazem, were added and the CAG with EM test was performed at the same time (protocol A). In protocol B, we changed the order of drug administration, i.e., on the 2nd day nifedipine, on the 3rd day diltiazem, on the 4th day nicorandil, and on the 5th day ISDN, were added. There was a significant increase in coronary diameter after the administration of vasodilators at the spasm sites in both protocols A and B. After a single administration of ISDN (protocol A) or nifedipine (protocol B), in 12 of 13 (protocol A) and in 10 of 12 coronary arteries (protocol B), spasms were again induced by EM at almost the same doses as those used before drug administration.