Atypical Infiltrates on Endomyocardial Biopsy are Associated with Adverse Outcomes in Pediatric Heart Transplantation

Purpose The significance of atypical infiltrates, defined as eosinophils or plasma cells on endomyocardial biopsy (EMB) after pediatric heart transplant (HTx) is not known. We hypothesize that atypical infiltrates are associated with worse post-HTx outcomes. Methods We performed a retrospective cohort study of 96 consecutive patients status-post primary HTx (age Results Atypical infiltrates were seen in 24/96 (25%) patients. Of these patients, 14/24 (58%) had 1 EMB and 10/24 (42%) had >2 EMB with atypical infiltrates. Atypical cells were abundant in 6/24 (25%), while they were a rare cell type in 18/24 (75%). The presence of atypical infiltrates on EMB was associated with higher likelihood of reaching the composite outcome compared to no atypical infiltrates (HR 6.9 [2.9-16.3], Fig 1A). Two or more EMBs with atypical infiltrates were associated with greater risk of composite outcome compared to no atypical infiltrates (HR 11.1 [4.2-29.1], Fig 1B). All patients with abundant atypical infiltrates met the composite outcome within the study period (HR 21.6 [7.7-60.2], Fig 1C, compared to no atypical infiltrates). Conclusion Atypical infiltrates on EMB are associated with increased risk of CAV, graft failure, or death after HTx. The risk is higher with increasing frequency and greater extent of atypical infiltrates on EMB. Patients with atypical infiltrates are an at-risk population that require close follow up.