P2.B024: Angiotensin II Type-1 Receptor Antibodies and Pediatric Heart Transplantation: A Case Series of a Single-Center Experience

Background: Orthotropic heart transplantation (OHT) is often the ultimate therapy for cardiac disease. There is limited data on the role of angiotensin type-II receptor antibodies (ATR1-Ab) in rejection after pediatric OHT. We describe our single-center pediatric experience managing patients with rejection and presence of ATR1-Ab.

Methods: Retrospective description of our institutional experience of all patients who underwent OHT and microscopic evidence of elevated ATR1-Ab levels.

Results: 5 patients were identified. Median age at transplantation was 9.6 years (Range: 4 months – 15 years). 3 patients (60%) were female. Indications for transplant included: decompensated congenital heart disease (20%) and dilated cardiomyopathy (80%). Median follow-up time after OHT was: 7.4 years (Range: 4.9 - 15.7 years). All patients were alive at last follow-up. Mean rejection episodes per year of follow-up before and after AT1R-Ab detection and treatment were 0.54 (SD = 0.4) and 0.3 (SD = 0.4), respectively. All patients received treatment with ACE blockers after biopsy identification. 2/5 (40%) patients received management with tocilizumab. Median EF at discharge from OHT was 66.8% (Range: 25.8 – 71.7%), median EF after biopsy identification was 61.5% (range: 56.4 – 65.9%), and median EF at last follow-up was: 64.9 % (55.1 – 68.5%)

Conclusion: To our knowledge, we present the first pediatric experience of patients with antibody-mediated rejection and elevated ATR1-Ab levels after OHT. It is important to recognize the role of ATR1-Ab in the development of antibody-mediated rejection. Further studies are needed to determine the exact role in the pathogenesis of rejection.