Tissue Doppler imaging for rejection surveillance in pediatric heart transplant recipients.

Background: Most transplant centers perform serial cardiac biopsies for rejection surveillance in pediatric heart transplant (HT) recipients. We sought to assess tissue Doppler imaging (TDI) findings during biopsy specimen-proven rejection in pediatric HT recipients and to develop TDI criteria for absence of rejection with high predictive accuracy.

Methods: We included the 122 HT recipients in follow-up at our center (median age at HT, 8.7 years). We identified all echocardiograms with adequate TDI data performed within 24 hours of a cardiac biopsy during 2005 to 2011. Rejection was defined as Grade ≥ 2R cellular rejection or antibody-mediated rejection. Paired comparisons of TDI velocities were made using patients' baseline velocities as the control.

Results: Overall, 647 specimen-pairs were identified where there was no rejection at baseline. In 24 of these, the second biopsy specimen demonstrated rejection. Using receiver operating characteristic curve analysis of percentage change from baseline, we identified < 15% decline in left ventricular (LV) S' velocity and < 5% decline in LV A' velocity to individually predict non-rejection with > 99% accuracy. When joint criteria were used, the predictive accuracy was 100%, and no rejection event was misclassified. More than 75% of TDI pairs met these criteria for non-rejection.

Conclusions: Biopsy specimen-proven rejection is associated with a significant decline in biventricular TDI velocities from baseline in pediatric HT recipients. By using well-defined TDI criteria to predict non-rejection, a substantial proportion of planned biopsies may be deferred or avoided at minimal risk to pediatric HT recipients.