pAMR DSA Dataset 11/2010 - 2/2023

Background: Surveillance donor-specific antibody (DSA) and pathologic antibody-mediated rejection (pAMR) testing is recommended in the first year after heart transplantation (HTx) in adult patients. Whether pAMR testing adds prognostic information to contemporary DSA testing has not been fully studied.

Methods: This was a single-center study of consecutive endomyocardial biopsies (EMB) performed between November 2010 and February 2023 in adult HTx patients. The primary objective was to evaluate whether pAMR testing contributes additional information to DSA testing to better predict overall survival. Secondary end-points included cardiac survival and allograft dysfunction.

Results: A total of 6,033 EMBs from 544 HTx patients were reviewed for the study. The pAMR+/DSA+ patients had significantly lower overall (pc = 0.013) and cardiac survival (pc = 0.002), while the pAMR+/DSA- and pAMR-/DSA+ patients showed no difference in either outcome compared to the pAMR-/DSA- group. We found significantly lower overall survival in pAMR+/DSA+ patients with allograft dysfunction (pc < 0.001) but not in pAMR+/DSA+ patients without allograft dysfunction (pc = 0.569), when compared to the pAMR-/DSA- without allograft dysfunction group. The pAMR+/DSA+ patients with cardiac allograft dysfunction accounted for 18% of deaths or cardiac retransplants while only representing 4% of the HTx cohort. Moderate or severe primary graft dysfunction (PGD) also was a novel risk factor for the development of de novo DSAs (dnDSA) by 4 weeks post-HTx (p = 0.025).

Conclusions: Surveillance DSA testing may effectively identify high-risk pAMR+ patients. Earlier DSA testing at 10 to 14 days post-HTx should also be considered in moderate or severe PGD patients.