The restoration of normal blood flow following a period of ischemia may result in ischemia / reperfusion injury (I/RI), which is characterized by inflammation and oxidative damage to tissues. Varying degrees of I/RI occur upon reperfusion of a donor heart after cold storage. Medications containing antibodies against immune cells have been used for many years as powerful immunosuppressants. These medications, called polyclonal antibody preparations, are generally only used immediately following transplantation and/or to treat rejection. At our institution, one such antibody preparation (Thymoglobulin) is used in most pediatric heart transplant recipients for 3-5 days immediately after transplantation. Because standard immunosuppressive medications (called calcineurin inhibitors) are toxic to the kidneys, the use of Thymoglobulin allows us to delay the initiation of calcineurin inhibitors until the kidneys of completely recovered from the shock of the transplant surgery.

We hypothesize that Thymoglobulin may be beneficial in reducing the damage caused by I/RI. Thus, the present study seeks to evaluate the effectiveness of an intra-operative dose of Thymoglobulin (in addition to the standard doses post-operatively) at reducing the effects of I/RI. The study will be a double-bind placebo-controlled trial involving 20 subjects. Biologic markers for I/RI will be assessed at periodic intervals for six months post-transplantation. Subjects receiving intra-operative doses of Thymoglobulin will be compared to the controls in order to assess the effectiveness of intra-operative Thymoglobulin in ameliorating the effects of I/RI.