The cytological technique was used to study autopsy specimens from 39 patients aged 35-85 years. Above the atherosclerotic strips and plaques there were multiple destruction microfoci (MDMs) of endothelial cells (EC), which were divided into three types. EC MDMs were detected in the aortic intima in 79.5% of the patients. A total of 107 MDM of different types were found in 63.2% of cases. A total of 53 MDMs were identified. The detection rate for EC MDMs in the aorta and coronary arteries in acute and recurrent myocardial infarction was 1.3 and 2 times greater than that in large-focal and diffuse small-focal cardiosclerosis. EC microfocal destruction is a sign of progressive atherosclerosis and may be a critical step in the transition from stable endothelized to eroded plaque and thrombosis.