Architecture of the thrombi removed from coronary artery bypass grafts in a patient with acute myocardial infarction.

Using scanning electron microscopy we analyzed thrombotic material removed from coronary bypass grafts in a 57-year-old woman with multilevel atherosclerosis presenting with acute myocardial infarction (AMI). A white thrombotic material removed from the marginal branch bypass that contained large amounts of activated platelets displaying pseudopodia clearly visible at a higher magnification with a relatively low amount of fibrin. The other thrombus obtained from the right posterior descendent branch (RPD) bypass showed a highly organized fibrin structure composed of thicker fibers with low amounts of cellular components. Our findings indicate that the thrombus structure is different in AMI patients in whom the infarct-related vessel is vein anastomosis compared to those with a native coronary artery occluded. These findings help explain resistance of such thrombi to fibrinolysis and faster plaque growth related to fibrin accumulation.