Background: Little has been reported on the clinical significance of asymptomatic antibody-mediated rejection (AMR) alone or mixed rejection (MR), defined as concurrent cellular rejection (CR) and AMR in heart transplantation. In this study, we examined whether a differential impact on cardiovascular mortality (CVM) existed when comparing asymptomatic AMR, to stable MR or CR.
Methods: The Utah Transplantation Affiliated Hospitals (UTAH) Cardiac Transplant Program pathology database of all heart transplant recipients between 1985 and 2004 was queried. Patients were classified as cellular, antibody-mediated, or mixed rejectors based on their predominant pattern of rejection type in the first three months post-transplant. Kaplan-Meier survival curves were fit to each of the three groups and analyses were adjusted for age at the time of transplant, gender, and underlying primary cardiac disease.
Results: Eight hundred and sixty nine heart transplant recipients qualified for analysis. Over the study period, patients with asymptomatic AMR or stable MR patterns had significantly worse CVM when compared to patients with stable CR pattern (AMR, 21.2%; MR, 18.0%; CR, 12.6%; AMR vs. CR, p = 0.009; MR vs. CR, p = 0.001). In contrast, CVM was comparable in patients with asymptomatic AMR or stable MR patterns (p = 0.9).
Conclusions: Asymptomatic or subclinical AMR and MR are clinically relevant, should be recognized, and deserve consideration for therapeutic intervention in hopes of avoiding adverse outcomes.