Management of vasospastic angina at rest with continuous infusion of isosorbide dinitrate: A double crossover study in a coronary care unit

Abstract

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 (T 1 and T 2) of 24 hours (four patients) or 12 hours (eight patients) alternating with two equal periods (P 1 and P 2) of infusion of saline solution with a double crossover design (T 1, P 1, T 2 and P 2). 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 P 1 and P 2, but was reduced to 13 and 20, respectively, during periods T 1 and T 2 ( P = 0.002). Transient ischemic attacks at rest were completely prevented during both T 1 and T 2 in four patients and during T 1 or T 2 in three patients, and were not abolished but significantly reduced in T 1 and T 2 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.