Pathological evaluation of coronary lesions in cases of cardiac rupture during acute myocardial infarction: An autopsy study of 148 out-of-hospital sudden death cases

We pathologically evaluated coronary artery lesions of left ventricular ruptures during acute myocardial infarctions (148 sudden out-of-hospital death cases; 93 men and 55 women; age range 42–94 years; mean age 68.9 years; 143 atherosclerotic and 5 non-atherosclerotic lesions). Among the 143 hearts with atherosclerotic coronary lesions, three-vessel disease was most frequent, and plaque rupture or erosion and occlusive thrombus were identified in most cases. Ages of the main component of the occlusive thrombus in the culprit coronary artery corresponded histopathologically to those of myocardial infarction. One of the most outstanding features in this pathological study is that acute thrombus in the culprit coronary artery was identified morphologically in most of the cases with advanced myocardial infarction (3 or more days). On the other hand, in cases of fresh myocardial infarction, a preceding mural non-occlusive organizing thrombus was observed mostly underneath the main component of the thrombus. It is suggested that, in most cases, cardiac rupture during acute myocardial infarction occurs at the time of a new ischemic event caused by a new thrombotic coronary lesion.