Endothelial Cell Injury in Cardiovascular Surgery: Atherosclerosis 11Recent discoveries in the field of vascular biology have led to an expanded understanding of the pathogenesis of many of the immediate and long-term complications of patients undergoing cardiovascular operations and interventional cardiologic procedures. In particular, the vascular endothelium has emerged as the central focus of many of the biologic events that affect the preoperative, operative, and postoperative course of nearly all heart surgery patients. A recurring theme in the study of endothelial cell biology is the crucial role that endothelial cell injury plays in the difficulties that our patients encounter. The deleterious effects of endothelial cell injury are most evident in the acute syndromes of vasospasms, coagulopathy, ischemia/reperfusion injury, and the systemic inflammatory response to cardiopulmonary bypass. In addition, chronic endothelial cell injury contributes to the development of anastomotic narrowing and the progression of atherosclerosis, both of which limit the long-term success of coronary artery bypass grafting. Because of the increasingly recognized role of the endothelium in cardiovascular function there is a tremendous amount of basic science information detailing the response of the endothelium to injury. This is the last in a series of seven reviews intended as an introduction to the major topics of endothelial cell biology that are of importance to the practicing cardiothoracic surgeon. In particular, the authors have focused on the role that the endothelium has on the development of vasomotor dysfunction, bleeding and thrombosis, neutrophil-endothelial cell interaction, and obstructive arteriopathy. The aim of these reviews is to provide a concise reference point for cardiothoracic surgeons as they evaluate the ever-accumulating research findings and new therapies that stem from the study of the endothelium in response to the insults encountered in cardiothoracic surgery.Edward D. Verrier, MD