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(Circulation. 2007;115:e388-e390.)
© 2007 American Heart Association, Inc.

Images in Cardiovascular Medicine

Electron Microscopic Insights Into the Vascular Biology of Atherosclerosis

Study of Coronary Endarterectomy Specimens

Komarakshi R. Balakrishnan, MD; Sarah Kuruvilla, MD; Aishwarya Srinivasan, MSc; Praveen Kumar Sehgal, PhD

From the Department of Cardiothoracic Surgery, Ramachandra Medical College, Chennai, India (K.R.B.), Department of Pathology, Ramachandra Medical College, Chennai, India (S.K.), and Department of Bioproducts, Central Leather Research Institute, Chennai, India (A.S., P.K.S.).

Correspondence to K. Balakrishnan, MD, Department of Cardiothoracic Surgery, Ramachandra Medical College, Chennai, India 600116. E-mail krbalakrishnan@vsnl.com

An extract of the first 250 words of the full text is provided, because this article has no abstract.

Coronary artery disease, typically discrete and proximal in distribution, is sometimes more diffuse in nature, in which case, it is often associated with poorer outcomes of revascularization. Does diffuse coronary artery disease represent an advanced and burned-out stage of atherosclerosis, representing a "metabolically inert graveyard" of atheromatous tissue, or is there ongoing atherosclerotic activity? To answer this question, plaques obtained during surgical coronary endarterectomy were examined using transmission and scanning electron microscopy, and the results form the basis of this study.

The various stages of atherosclerotic plaque progression are well known¹ and could be clearly identified in different regions of the same plaque under electron microscopic examination. Figure 1 shows monocytes diapedesing between the endothelial lining of the coronary lumen to enter the intima. In other regions, macrophages were seen phagocytosing lipid droplets and being transformed into foam cells (Figure 2). Foam cells of smooth-muscle origin with surrounding collagen deposition could also be seen (Figure 3). The role of plaque neovascularization in recruiting macrophages into the plaque was also graphically captured; we have previously published these observations.² Transmission electron microscopy offers some unique insights into the mechanisms of plaque calcification. The process seems to start as an encrustation around individual microvesicles of lipid, eventually coalescing to form larger clumps of calcification (Figure 4). Scanning electron microscopy of the same plaque revealed areas of endothelial erosion and plaque fissuring (Figure 5).

View larger version (149K):   Figure 1. Monocyte diapedesing between the endothelial cells of the coronary artery . . . [Full Text of this Article]