Evaluation of Induction Strategies in Heart Transplant at a Single Center

Abstract

Immunosuppression induction is commonly utilized in heart transplant (HT) to prevent acute rejection and/or delay calcineurin inhibitor (CNI) initiation. However, guidance on whether to use induction and preferred agent(s) are not well defined. This is reflected by high practice variability across centers. According to ISHLT registry data, 54% of adult HT cases utilized induction, 31% with an IL-2R antagonist and 23% with a T-cell depleting agent. Our center has primarily utilized 3 strategies based on rejection risk and need to delay CNI: IL-2R antagonist (basiliximab), T-cell depleting (anti-thymocyte globulin, rabbit (rATG)), or no induction. Our study's objective was to compare these strategies' safety and effectiveness. A retrospective chart review was conducted at a large academic medical center, including HT cases performed between January 2015 and April 2019. Patients were stratified by induction strategy used at the time of transplant. The primary outcomes were rate of biopsy-proven acute cellular rejection (ACR) grade 2R or higher, treated antibody mediated rejection (AMR), and any infection within one year of transplantation. From January 2015 to April 2019, 145 total HTs were included in our study (123 heart, 20 heart-kidney, and 2 heart-liver). rATG was the most common induction strategy used (36%), followed by no induction (35%), and basiliximab (26%). Four patients (3%) received 1 dose of basiliximab but were switched to rATG. ACR rates were not statistically different among induction groups: 22% with no induction, 11% with basiliximab, 17% with rATG, and 0% with combination (p = 0.51). AMR rates were also not statistically different: 6% with no induction, 5% with basiliximab, 4% with rATG, and 0% with combination (p = 0.93). There was no difference detected in donor-specific antibody (DSA) formation at 1 year (p = 0.81). The percentages of patients with any infection were: 53% with no induction, 55% with basiliximab, 62% with rATG, and 75% with combination (p = 0.90). Incidences of ACR, AMR, DSA formation, and infection were not statistically different among induction strategies at one year post-transplant. It may be beneficial to individualize induction strategies based on recipient factors at the time of transplantation. Long term outcomes in this patient cohort are yet to be determined.