Pathology of coronary artery bypass graft surgery.

Coronary artery bypass graft surgery has been available and widely successful for the symptomatic treatment of ischemic heart disease. Despite its widespread use, there is little information available on the pathological consequences of this procedure on the human heart. In this article, morphological consequences of coronary artery bypass graft surgery is reviewed. Intimal changes occurring within the vein graft itself consist predominately of fibrous initimal proliferation, which in some patients may progress to from an occlusive plaque. Most occlusions, however, occur at the coronary artery bypass graft anastomosis site and the mechanisms of occlusion include compression of the vascular lumen, thrombosis, and dissection of the coronary artery. Most graft failure occurs in the setting of too small a native coronary artery lumen. The myocardium is also at risk for alterations as a result of the bypass operation. Contraction band or reperfusion necrosis is the type of injury most commonly seen, and it appears to occur most often in the distribution of patent grafts. Accelerated atherosclerosis in vein grafts and the myocardial injury associated with revascularization require further detailed morphological studies, but these are important areas for pathological exploration since they bear on important and yet unanswered questions about coronary bypass surgery: can it in the long run perserve myocardium and prolong life?