INTIMAL NEOVASCULARIZATION IN HUMAN CORONARY ATHEROSCLEROSIS - ITS ORIGIN AND PATHOPHYSIOLOGICAL SIGNIFICANCE

To investigate the histopathological characteristics of the newly form ed vessels in the atherosclerotic intima of human coronary arteries, w e conducted postmortem angiography in 31 cases, including 11 with myoc ardial infarction. Vessels were examined three-dimensionally under the stereoscope. In addition, we evaluated 25 anterior descending coronar y arteries unrelated to the occurrence of myocardial infarction by lig ht microscopy using 3-mm stepwise sections and 5-mu m serial sections. Histological alterations were analyzed morphometrically to determine the correlation between the degree of intimal neovascularization and t he growth of the endothelium into the atherosclerotic intima from the adventitia or lumen. There was a significant positive correlation betw een the density of new vessels in the intima and the incidence of lumi nal stenosis, the extent of chronic inflammatory infiltrate, the forma tion of granulation tissue, or the atheromatous changes, whereas the v ascular density decreased in the extensively hyalinized and calcified intima. The newly formed intimal vessels originated mainly from the ad ventitial vasa vasorum and also partly from the proper coronary lumen. The intimal vessels that originated from the adventitia occurred appr oximately 28 times more frequently than those that originated from the luminal side. The frequency of former vessels increased as the lumina l stenosis became more severe, whereas the latter vessels were found m ost frequently in the presence of 40% and 50% stenosis. Vessels origin ating from the proper lumen were more often associated with fresh or o ld hemorrhage. We conclude that intimal neovascularization largely ori ginates from the adventitia and is closely associated with the extent of coronary stenosis and the histological inflammatory reaction. Hunt PATHOL 26:450-456. Copyright (C) 1995 by W.B. Saunders Company