A Study to Compare the Effectiveness of a Drug That Suppresses the Immune System Called Thymoglobulin® in Preventing the Development of a Disease That Affects the Majority of Heart Transplant Recipients Called Cardiac Allograft Vasculopathy (CAV)

The purpose of this study is to test the hypothesis that administering Thymoglobulin® induction therapy early after transplant prevents the development of cardiac allograft vasculopathy (CAV). CAV accounts for a significant number of deaths in cardiac recipients after the first year of transplant. At 5 years post-transplant 30% of the deaths are due to CAV. With the exception of re-transplantation the available treatments for CAV are only effective at inhibiting its progression. CAV involves only the allograft and spares the native arteries, suggesting an immunologic basis for the disease. However, both immunological and non-immunological factors contribute to the development of CAV. The established immunological risk factors are recurrent rejection and humoral/antibody-mediated rejection (AMR). Non-immunological risk factors identified include preservation injury, the cause of donor death, donor graft ischemic time, and cytomegalovirus infection1. It is hypothesized that these factors increase the risk of developing CAV by causing early endothelial damage to the graft, which then could promote increased lymphocyte-endothelial interactions and the production of anti-endothelial antibodies2. The investigators hypothesized that Thymoglobulin induction therapy would prevent the development of CAV because its polyclonal nature allows Thymoglobulin to target all the potential mechanisms that contribute to the development of CAV-T-cell activation, B-cell activation, antibody formation, induction of tolerance, and modulation of lymphocyte-endothelium interactions3. Because the mechanism by which Thymoglobulin affects the immune system are still poorly understood, the investigators will also study how Thymoglobulin changes the immune system over time in the heart transplant recipient as a secondary objective.