Less Invasive Acute Rejection Surveillance After Pediatric Heart Transplantation: Experiences From a Low-intensity...

Acute rejection remains a leading cause of morbidity and mortality early after pediatric heart transplantation (HT). Current guidelines recommend only endomyocardial biopsies (EMB) as reliable for rejection surveillance. We purposed to explore clinical outcomes of less invasive rejection surveillance in a low-intensity biopsy center in pediatric heart recipients.

We retrospectively analyzed data from 46 pediatric heart recipients (median age 5.7 y; interquartile range [IQR], 2.5-8.0) discharged between 2011 and 2021. Clinical and echocardiographic evaluations were performed frequently, whereas protocol-based routine EMB were scheduled only at 1 and 2 y post-HT. Additional biopsies were performed if new-onset symptoms and/or a decline in graft function, as assessed by echocardiography, including tissue Doppler imaging (TDI)-derived velocities, were detected.

Graft survival was not compromised by less invasive surveillance with 97.8% at 1 y and 95.7% at 2 y post-HT. A total of 680 echocardiograms (median 15 per recipient; IQR, 13-17) and 140 biopsies (median 3 per recipient; IQR, 2-4) were analyzed. Acute rejection (4 acute cellular rejection and 8 antibody-mediated rejection) was found in 8.5% of the EMB. None of the protocol-based routine EMB of asymptomatic patients revealed rejection. Absence of a reduction in TDI-derived left ventricular and interventricular septal systolic velocities, combined with clinical evaluation, correlated with nonrejection.

Combining frequent clinical follow-up with echocardiographic assessment using TDI as a less invasive method of rejection surveillance did not compromise long-term clinical outcomes. Validated in larger pediatric cohorts, it could save invasive biopsies, reducing the risk of biopsy-related complications and medical costs.