HEMORRHAGIC LESIONS OF THE CORONARY ARTERIES

Several types of acute occlusion of the coronary arteries have been described.¹ Interpretation of the pathologic changes associated with the more familiar form, usually accompanied by arterial thrombosis, has not resulted in a clear understanding of the basic factors involved. In recent years more emphasis has been accorded to the hemorrhage in the intimal and subintimal layers of the occluded arteries, and several authors have attached great importance to this phenomenon in the mechanism of coronary occlusion.² This has resulted partly from a relatively new interpretation of the origin and significance of hemorrhage in the walls of small arteries.³ It had generally been considered that extravasated blood in this location either was derived from the lumen of the artery or occurred as a result of inflammatory exudation.⁴ Lately it has been demonstrated that in most instances intramural hemorrhage of the coronary artery arises from the vascular