Vascular rejection in cardiac transplantation: Histologic, immunopathologic, and ultrastructural features

Although the majority of rejection found in cardiac transplant biopsies is cellular in type, a variety of vascular alterations occur in cardiac biopsies, constituting different forms of rejection that can be recognized using light microscopic and immunopathologic criteria. In this report, pathologic aspects of the vascular alterations associated with vascular and mixed rejection of cardiac allografts are described in detail. Methods and controls used in this report are identical to those previously reported. The histologic, immunopathologic, and ultrastructural findings associated with vascular rejection and other vascular processes in cardiac allografts are discussed. The relationship of these findings to chronic allograft rejection and potential pathogenetic mechanisms of these vascular changes are also detailed.