Surgical Experience With Retroperitoneal Heterotopic Heart Transplantation in the Large White Domestic Swine

Abstract

Accelerated coronary atherosclerosis following heart transplantation is the main limiting factor for long-term survival, aside from graft failure and complications due to immunosuppression. Graft coronary vasculopathy is due to chronic rejection of the vascular wall leading to intimal hyperplasia in coronary arteries. Numerous heterotopic heart transplantation models have been used in different species to study the immunology and pathophysiology following graft implantation. This study reports our experience with the retroperitoneal heterotopic heart transplantation in Large White domestic swine using immunological typing. This approach mimics the kinetics of slow low-grade rejection in clinical human heart transplantation. One hundred and fifty-four retroperitoneal ( n = 154) heterotopic heart transplantations were performed using Large White swine sampled for the majorhistocompatibility class (MHC) class I antigen and blood type using the microlymphotoxicity technique. Acute rejection studies were performed by intentional mismatch of the swine lymphocyte alloantigen (SLA) and chronic rejection studies were done in allografts implanted in donor-recipients matched for blood type and class I antigen to assess the effects of rejection per se, hypercholesterolemia, intracoronary L-NAME infusion, and endothelial denudation on the development of graft coronary vasculopathy. Assessment of in vitro coronary arterial vascular reactivity in standard organ chamber experiments comprised the core of vascular biology studies in this large animal model. Eighty (52%) transplanted recipients survived until the elective date of sacrifice at 60 days, 14 (9.1%) died during the surgery, 21 (13.6%) died < 24 h after the transplant, and 8 (5.2%) died of late deaths. The retroperitoneal heterotopic heart transplantation model with blood typing and determination of the SLA class I antigen is a useful model for the study of immunological and vascular events due to graft rejection after heart transplantation.