[Unstable angina: observtions on 187 patients of whom 84 were operated on for aorto-coronary bypass (author's transl)].

Clinical data, EKG and coronary angiography of 187 patients with unstable angina are given. The patients are divided into 4 groups: spontancous angina, spontaneous angina Prinzmetal's variant, "in crescendo" agina, intermediate syndrome. 103 patients were treated with pharmacological therapy only and 84 underwent aortocoronary bypass; 2 of them were operated on for acute myocardial infarction. The clinical and pathologic peculiarities of two groups are not similar and therefore the results are not comparable. There was a mortality rate of 10.3% of patients with pharmacological treatment and the incidence of non fatal myocardial infarction was 10.4%. The mortality during operation was 14.2% and the incidence of non fatal myocardial infarction was 13.1%. The spontaneous angina and Prinzmetal's variant often had normal rest EKG and a very similar coronary angiographic pattern, with obstructive lesions often localized in the proximal part of a single vessel. In 9% of cases coronary arteries were normal. The incidence of serious arrhythmias was higher in Prinzmetal's variant than in other types of unstable angina. The mortality in patients with Prinzmetal's angina was particularly high during the first period of experience (1970-1973) when the operation was performed after a few days of unsatisfactory results with pharmacological treatment; it decreased after patients underwent operation in an attenuate phase of the disease. The rest EKG of "in crescendo" angina was almost always pathologic; these cases presented obstructive lesions of 2 or 3 coronary arteries, functional impairment of left ventricle, collateral circulation. The mortality in patients treated with pharmacological therapy was higher than in other types of unstable angina. The mortality during operation, fairly high in the first period of experience, decreased in this group of patients as well, during the second period of experience.