Impact of Blood Group A Subtyping on Heart Transplantation: A Single Center Experience

Purpose ABO antigens are ubiquitously expressed not only on RBCs but also on vascular endothelium. Blood groups A and AB have 20 different subytpes, A1 being most common (80%), followed by A2(19%) and remainder Methods We retrospectively tested for presence of A1 antigen and anti-A1 isoagglutinins on 51 adult post-heart Tx patients with either A or AB blood group at our institution. Patients were divided into 2 groups based on presence of A1 antigen, A1 or non-A1 subtype. Primary endpoint was freedom from rejection at 6 months. Secondary endpoints included graft dysfunction, cardiac allograft vasculopathy (CAV) and re-transplantation. Results Of the 51 study participants, 43 were A1 and 8 were non-A1 subtype. None of the non-A1 subtype recipients had detectable anti-A1 isoagglutinins despite 5/8 donor hearts were A1. Mean follow up time post-Tx was 61.8±44.5 months (non-A1) and 91.8±79 months (A1, p=0.15). No significant difference was noted between two groups in terms of freedom from rejection at 6 months (non-A1: 3, A1: 15, p=0.39), graft dysfunction on echocardiogram (non-A1: 1, A1: 4, p=0.88), CAV (non-A1: 0, A1: 5, p=0.29), and re-transplantation (A1: 0% vs non-A1: 0%, p=1). Conclusion Transplantation of A1 donor hearts to non-A1 recipients in the absence of anti-A1 isoagglutinins does not affect post heart Tx outcomes in terms of rejection, graft dysfunction, CAV, or retransplantation.