EMB, the gold standard for diagnosis of ACR, poses unique risks in children. Limited cross-sectional data have associated LV MPI with ACR. We hypothesize that a relative change in MPI from baseline without ACR to the time of ACR will better detect ACR than an absolute threshold LV MPI value. We identified 40 children with ACR ≥60 days post-transplant matching them by age and time from transplantation to 40 children without ACR. There was a significant increase in LV MPI at time of ACR vs. baseline (0.59 ± 0.17 vs. 0.41 ± 0.11; p < 0.001). There was no difference in LV MPI between baseline and follow-up (0.41 ± 0.11 vs. 0.42 ± 0.11; p = 0.65). An absolute increase in LV MPI of ≥0.47 had 82.5% sensitivity and 85% specificity for ACR, whereas an increase in LV MPI from baseline of ≥20.4% was 90% sensitive and 100% specific. Serial measurement of LV MPI appears to be a sensitive and specific marker of ACR. LV MPI shows good interobserver agreement and increases at the time of EMB-proven ACR with subsequent resolution to baseline measurements upon EMB-proven resolution of ACR. Future studies in larger, prospective cohorts should be undertaken to validate these findings.
Keywords: acute rejection; echocardiogram; heart transplant; myocardial performance index; pediatric.
© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.