Relationship between myocardial infarction and preinfarction angina: a histopathological study of coronary arteries in two sudden death cases employing serial section.

Two patients who had previously experienced old myocardial infarction and who died suddenly after an attack of chest pain were examined and discussed. In both cases two of the three main coronary arteries showed severe stenosis with canalization. Ruptured atheromatous plaque was found in the unblocked coronary artery. Fibrin was already formed and surrounded the fractured intimal collagen fiber, foam cells, and cholesterin clefts, but a luminal thrombi had not yet been formed. Fresh occluding thrombi were formed at the site of the ruptured atheromatous plaque. Coronary thrombi containing abscess components such as foam cells, cholesterin clefts, and the fractured intimal collagen fiber were found in our preliminary study. These views support the supposition that this fracture between the lumen and the plaque might precede and be responsible for the formation of the thrombus and the onset of acute myocardial infarction. It was confirmed that the attack of preinfarction angina occurred at the time of the rupture of the atheromatous plaque. The rupture of the atheromatous plaque plays an important part as an initiating factor of peinfarction angina and myocardial infarction. Thus, it is necessary to examine coronary arteries by serial histopathological section method.