Focal myocardial ischemic necroses associated with unstable angina pectoris.

Objectives: We sought to determine whether myocardial lesions develop in association with unstable angina pectoris.

Background: We observed a patient with unstable angina pectoris who developed foci of ischemic necroses in the distribution of a single coronary artery. The artery had an atherosclerotic plaque that had undergone ulceration of its fibrous cap. This case prompted us to study the occurrence of focal myocardial ischemic necroses in other patients with unstable angina pectoris.

Methods: Focal ischemic injuries of an age consistent with the duration of the episode of unstable angina pectoris were observed in 6 of 21 patients who died after hospital admission. The 21 patients had not undergone any invasive coronary procedures or thrombolysis, and the heart had been examined after postmortem arteriography and fixation in distension.

Results: Of the six patients with focal ischemic lesions, three had foci of contraction band necrosis and three had focal areas of ischemic necrosis in a state of early repair. Three had a recent myocardial infarct of an age less than the duration of unstable angina pectoris. In each of the six patients, the histologic age of the focal myocardial lesions correlated with the time frame of unstable angina.

Conclusions: We conclude that the focal ischemic injuries observed in the myocardium were due to ischemic episodes that also produced the clinical manifestations of unstable angina pectoris.