Impact Of Therapy With Anti-Thymocyte Globulin In Heart Transplant Recipients On Acute Cellular Rejection And Readmission For Infection - A Single Center Retrospective Study

Background Approximately 20% of all orthotropic heart transplant (OHT) recipients in the US receive anti-thymocyte globulin (ATG) post-transplant to prevent acute rejection, however use varies between centers. There is lack of prospective multi center clinical trials assessing long-term survival benefit of early ATG treatment including readmission for infections compared with no induction in OHT patients. We aim to review the role of ATG use during the index hospitalization for OHT to prevent acute cellular rejection (ACR) and evaluate the impact of ATG in readmission rates for infection at our center. Hypothesis We hypothesize that therapy with ATG improves freedom from ACR but may result in higher readmission rates for infection. Methods We performed a retrospective cohort study of 98 adults who underwent OHT at a single center from January 2014 to December 2019. Patients without one year follow up and those who underwent heart-kidney transplant were excluded. We compared baseline characteristics and analyzed outcomes between patients with and without ATG administration using standard statistical methods. Unadjusted Kaplan-Meier curves were used to study differences in ACR and hospitalization for infection between patients with and without ATG administration. Results 53 OHT patients received ATG and 45 patients did not. There was no significant difference in death at one year (p=1.0), ACR (p=0.17) or readmission for infection (p=0.35) between the two groups. Patients receiving ATG had delayed date to first ACR (p=0.038), with a median time of first ACR of 100 days versus 26 days post-OHT in the non-ATG group. Conclusion Treatment with ATG during the index hospitalization for OHT delayed the time of first ACR but not the overall burden of rejection in the first year. The rate of freedom from infection was similar in both groups along with overall mortality. As this is a retrospective observation we will analyze the use of ATG in selected patients at high risk for rejection or for renal sparing.