Pathology of stable and unstable angina pectoris.

The clinical and pathological data from 46 patients who died during or shortly after coronary bypass surgery and one patient who died shortly after angiography were studied. Each patient was placed into one of three clinical categories of angina pectoris. Twelve were classified as having unstable angina pectoris, 20 as stable severe angina, and 15 as stable moderate angina. No significant difference was found between the three catagories whem age, sex, presence of hypertension, lipid abnormalities, diabetes, smoking, family history of myocardial infarction, or history of previous mycardial infarction were examined. Most patients in all classes of angina had extensive atherosclerotic coronary disease: 12 patients had triple vessel plus left main disease; 25, triple vessel disease; nine double vessel disease; and only one, single vessel disease. There was no difference in severity or distribution of coronary disease when the three catagories of angina were compared. Thirty-six of the 47 patients had evidence of scarring of one or more aspects of the left ventricular wall. There was likewise no significant difference between extent and distribution of myocardial scarring between the three clinical categories. Four of the 12 patients with unstable angina pectoris had pathologic evidence of preoperative myocardial infarction, whereas this was not found in any of the 35 patients with stable angina.