Long-term effectiveness of verapamil in stable and unstable angina pectoris. One-year follow-up of patients treated in placebo-controlled double-blind randomized clinical trials

The clinical responses to 12 months' treatment with verapamfl were evaluated in 63 patients with stable and unstable angina pectoris in whom the effectiveness of verapamil had been established in short-term double-blind placebo-controlled randomized clinical trials. In 41 patients with effort-related angina, long-term responses were sustained for periods exceeding 1 year. Twenty patients were evaluated by clinical history and showed a sustained reduction in frequency of anginal attacks and consumption of nitroglycerln with verapamil compared with the initial placebo control periods; the magnitude of this benefit was similar to that observed during doubleblind treatment with the drug. Twenty-one patients were evaluated by serial treadmill exercise testing and showed a sustained improvement in exercise duration after 4, 8, 16, 24, and 52 weeks of verapamil treatment; withdrawal of the drug resulted in a deterioration of exercise performance to levels similar to those seen before initiation of therapy. In 22 patients with unstable angina at rest, verapamil produced an amelioration of anginal symptoms that was sustained in most patients for longer than 1 year. However, these patients continued to have a high incidence of death and myocardial infarction in a frequency similar to that previously reported in large clinical studies using either combinations of verapamil and nitrates, nifedlpine and propranolol, or propranolol and nitrates. Calciumchannel antagonists may decrease the number of patients requiring coronary artery bypass surgery for relief of refractory angina, but they do not appear to alter the natural history of the disease.