(363) Proceeding with Heart Transplant in Flow Positive Cyto-Negative Prospective Donor-Specific Crossmatch in Highly Sensitized Patients: Saving Lives

PurposeSensitized patients undergoing HTx have greater risk of antibody mediated rejection (AMR), cardiac allograft vasculopathy (CAV), and decreased survival. A prospective crossmatch is performed on highly sensitized patients pre-HTx. While a cytotoxicity-positive complement test may be prohibitive for HTx, patients with flow-positive but cytotoxicity-negative crossmatch undergo HTx at our program. We reviewed outcomes of these patients.Methods60 highly sensitized patients with flow-positive yet cytotoxicity-negative prospective crossmatches 2010-2021 were evaluated. Outcomes assessed: 5-year survival and 5-year freedom from CAV (stenosis ≥40% by angiography), non-fatal major adverse cardiac events (NF-MACE: myocardial infarction, heart failure, percutaneous intervention, pacemaker, or stroke), and 1-year freedom from rejection [any treated rejection (ATR), acute cellular rejection (ACR), and AMR]. A subgroup was analyzed for the impact to outcome of T-cell and B-cell flow positivity (median channel shifts, MCS >200 and <200) and for Class I vs Class II donor-specific antibodies (DSA). A control group consisted of non-sensitized patients (n=540).Results5-year survival, freedom from CAV and NF-MACE were comparable between flow-positive cytotoxicity-negative patients and controls. These patients, however, had lower freedom from ATR/AMR (Table). There was also lower freedom from ATR/AMR in those with higher flow MCS though no difference based on Class I vs II DSA.ConclusionPatients with flow-positive cytotoxicity-negative prospective crossmatches have comparable 5-year outcomes to nonsensitized patients. Despite increased ATR, there is no impact on survival or CAV development. These findings support proceeding with transplantation in this high-risk group. Sensitized patients undergoing HTx have greater risk of antibody mediated rejection (AMR), cardiac allograft vasculopathy (CAV), and decreased survival. A prospective crossmatch is performed on highly sensitized patients pre-HTx. While a cytotoxicity-positive complement test may be prohibitive for HTx, patients with flow-positive but cytotoxicity-negative crossmatch undergo HTx at our program. We reviewed outcomes of these patients. 60 highly sensitized patients with flow-positive yet cytotoxicity-negative prospective crossmatches 2010-2021 were evaluated. Outcomes assessed: 5-year survival and 5-year freedom from CAV (stenosis ≥40% by angiography), non-fatal major adverse cardiac events (NF-MACE: myocardial infarction, heart failure, percutaneous intervention, pacemaker, or stroke), and 1-year freedom from rejection [any treated rejection (ATR), acute cellular rejection (ACR), and AMR]. A subgroup was analyzed for the impact to outcome of T-cell and B-cell flow positivity (median channel shifts, MCS >200 and <200) and for Class I vs Class II donor-specific antibodies (DSA). A control group consisted of non-sensitized patients (n=540). 5-year survival, freedom from CAV and NF-MACE were comparable between flow-positive cytotoxicity-negative patients and controls. These patients, however, had lower freedom from ATR/AMR (Table). There was also lower freedom from ATR/AMR in those with higher flow MCS though no difference based on Class I vs II DSA. Patients with flow-positive cytotoxicity-negative prospective crossmatches have comparable 5-year outcomes to nonsensitized patients. Despite increased ATR, there is no impact on survival or CAV development. These findings support proceeding with transplantation in this high-risk group.