EARLY AND LATE REJECTION AND HLA SENSITIZATION AT TIME OF HEART TRANSPLANT IN PATIENTS BRIDGED WITH LEFT VENTRICULAR- ASSIST DEVICES (LVAD):

P631 Aims: Over the years, the frequency of heart transplant candidates with pre-formed antibodies against HLA antigens has increased as a result of the number of patients bridged to transplant using LVAD’s. HLA sensitization has been demonstrated to be a risk factor in heart transplantation.. Methods: Herein are examined 119 patients who were bridged to transplant by LVAD’s for a relationship between HLA antibodies and early (30 days) and late (2 years or more) rejection as evidenced by endomyocardial biopsies. Both cytotoxic panel reactive antibody reactions against a panel of T lymphocytes (T-PRA) and the percent (%) of transplants that occurred across a positive class I flow crossmatch were examined. Biopsies were scored using ISHLT criteria. Results: Results are shown in the table for biopsy results at 30 days as well as for the highest grade of rejection at two years or beyond. At 30 days, the patients who had a biopsy grade of 0 had a mean T-PRA at transplant of 2.2%, while the mean PRA’s of the other biopsy grades were significantly higher (oneway). A similar pattern was seen with the highest biopsy results at two years or later. None of the patients who had a grade 0 biopsy had a positive flow cytometry class I crossmatch which was significant for the 30 day biopsy (chi square, grade 0 vs others), although this did not reach significance with the later biopsies, perhaps due to the small number of patients (n=3) who had negative biopsies. Conclusions: In conclusion, we found that when biopsy results were examined early or late post-transplant, patients with negative biopsy results tended to have less HLA sensitization as evidenced by low T-PRA’s and negative class I crossmatches. While the methods of HLA sensitization involve humoral responses, more aggressive immunosuppression might be warranted in an attempt to reduce cellular rejection post-transplant when HLA class I antibodies are present at the time of transplant.Figure