ULTRASTRUCTURAL FINDINGS IN CARDIAC TRANSPLANT RECIPIENTS

Ultrastructural findings in 350 endomyocardial biopsy specimens and 59 autopsy or explanted hearts from cardiac transplant recipients are reviewed. Myocyte degeneration can be readily distinguished from necrosis by the technique described. Vascular changes of endothelial activation, endothelial cell damage, and basement membrane reduplication can be readily identified. In addition, the myofilament composition of ischemic hearts in patients with allograft coronary artery disease is distinctive: There is a disproportionate loss of actin over myosin, giving a coarse appearance to the myofilaments. These changes are useful in further defining the morphologic features associated with rejection and ischemia in cardiac transplant recipients.