[Coronary artery thrombosis in myocardial infarct]

Coronary arteries of the heart of 94 patients who had died of large-focus myocardial infarction (at least one necrosis focus size of 3 cm or more) were examined. The arteries were analysed in cross sections after their removal from the heart. No subendocardial myocardial infarctions were included in the analysis. The duration of infraction varied from 2 hours to 56 days. Obturating thrombi of coronary arteries were found macroscopically in 90 (95.5%) out of 94 observations of myocardial infarction. Thrombosed parts of the arteries were examined histologically throughout their length. In 78 (86.6%) out of 90 observations of myocardial infarction, thrombosed parts of coronary arteries showed breaks in degeneratively-necrotically changed fibrous cover of the plaques. Different parts of thrombi in coronary arteries frequently have different structure and various degrees of organization. There was a correlation between the age of individual parts of coronary thrombi and myocardial infarction. The presence in thrombi of older parts than myocardial infarction indicate that the latter developed upon progression (increasing in size) of the thrombus. The coronary arteries thrombosis is the main pathogenetic factor of the development of large-focus myocardial infarction, and the above-mentioned changes in the vessel wall play an important role in its development.