MANAGEMENT OF VASOSPASTIC ANGINA AT REST WITH CONTINUOUS INFUSION OF ISOSORBIDE DINITRATE - DOUBLE CROSSOVER STUDY IN A CORONARY-CARE UNIT

Twelve patients were studied who had frequent transient ischemic episodes at rest with a variable degree of coronary atherosclerosis and vasospastic origin of angina as evidenced by good exercise tolerance and results of thallium-201 scintigraphy during angina at rest, ergonovine maleate provocative test and coronary angiography. With the aim of keeping a constant blood drug level, the trial consisted of a continuous intravenous infusion of isosorbide dinitrate (1.25 to 5.0 mg/hour) during two periods (T1 and T2) of 24 hours (four patients) or 12 hours (eight patients) alternating with two equal periods (P1 and P2) of infusion of saline solution with a double crossover design (T1, P1, T2 and P2). Continuous electrocardiographic monitoring revealed that the total number of transient ischemic attacks at rest characterized by S-T segment elevation (four patients), S-T depression (two patients) and either S-T depression or elevation (six patients), with or without pain, was 100, 104 and 91, respectively, during the introductory control period and during P1 and P2, but was reduced to 13 and 20, respectively, during periods T1 and T2 (P = 0.002). Transient ischemic attacks at rest were completely prevented during both T1 and T2 in four patients and during T1 or T2 in three patients, and were not abolished but significantly reduced in T1 and T2 in the other five patients. The reduction in ischemic attacks was similar for episodes characterized by S-T segment elevation or depression and with or without pain. Side effects were negligible. Therefore, infusion of isosorbide dinitrate appears to be a very effective treatment for patients with vasospastic angina at rest. © 1979.