Influence of HLA-DR Mismatches on Long Term Outcomes Following Heart Transplant

Abstract

There are conflicting reports on the effect of donor-recipient HLA-DR matching in heart transplantation. Studies have shown HLA-DR matching reduces the incidence of graft rejection within the first year and improves short term graft survival It is not known if HLA-DR matching impacts long term outcomes. We sought to analyze the effect of HLA-DR mismatch on long term survival, and also explain possible mechanisms. All adult heart transplants performed at our institution from 2000 to 2010 were retrospectively reviewed. Multi-organs, patients who expired within the first year after transplant and those with missing data were excluded. Patients were grouped according to number of HLA-DR mismatches: 0, 1 or 2. We analyzed allograft function [using most recent ejection fraction (EF)], development of significant (ISHLT grade ≥2) cardiac allograft vasculopathy (CAV) and survival. ANOVA used for analysis. Kaplan-Meier survival curves generated. P value <0.05 considered significant. 172 heart transplant recipients were included in the analysis. HLA-DR mismatch status was as follows: 9 (5.2%) had 0, 63 (36.6%) had 1, and 100 (58.1%) had 2 mismatches. There were more men in the group with 2 mismatches (82% vs 74.6% vs 66.7%, P<0.0001).There was no difference in the development of significant CAV in the three groups (33.3% vs 17% vs 12%, P=0.23). There was no difference in the severity of CAV (mean ISHLT grade 1.11±1 vs 0.7±1 vs 0.57±0.8, P=0.23). Mean EF was no different between the three groups (63.9±12.9% vs 68±6.4% vs 68.5±5.5%, P=0.12). 10 yr survival was similar in the three groups (77.8% vs 68.1% vs 58.4%, P=0.44). In our cohort, HLA-DR mismatches did not influence graft function, development of and severity of angiographically significant CAV. There was no impact on long term patient survival. HLA-DR matching prior to heart transplant may not be justified given the increased cost and logistical burden of HLA matching and longer cold-ischemic times that may result from reliance on tissue typing.