Endomyocardial Biopsy following Heart Transplantation in Children: A Single-Center Experience

Introduction: Transplant rejection is a common and severe risk after heart transplantation, especially within the first 6 months after HTX. In addition to examinations such as ECG and echocardiography, endomyocardial biopsy (EMB) is a common and suitable method for surveillance of cardiac allograft rejection even in a preclinical phase. To date, there are no common guidelines for the surveillance of cardiac allograft rejection in children.

Methods: We included 7 consecutive patients (6 females, mean age 9.7 ± 4.5) undergoing heart transplantation from 2010 to 2016 due to DCM in 6 cases and RCM in 1 case retrospectively,(one patient had to be excluded due to hyperacute rejection immediately after HTX). In total, 90 endomyocardial biopsies were performed, most of them routinely, weekly during the first 4 weeks, followed by every 2 weeks for one month, then monthly for another month followed by once every 3 months to the end of the first year and once every 6 months until the end of 2 years after transplantation. After the first 2 years we performed biopsies once per year. 10 of the 90 EMB were performed due to suspicious findings in ECG or Echocardiography or in short intervals after acute rejection. In case of results indicating acute rejection, patients were treated with high- dose prednisolone under close monitoring.

Results: In 10 out of 90 (11.1%) endomyocardial biopsies, an acute rejection was diagnosed(0 R n = 56, 1R n = 24, 2R n =7, 3R n = 3). In 1 out of 90 biopsies (1.1%), one minor complication (pericardial effusion managed conservatively without sequelae) occurred. After an average follow up period of 2.9 years ± 2 years, all patients survived without re- transplantation. Ejection fraction in these patients decreased from 70% ± 5% before first rejection to 55% ± 10 at last follow-up visit. However, in some cases of acute rejection, there were no abnormal findings in echocardiography or in ECG (n = 6; 7.5%).

Conclusion: According to our preliminary results, routinely performed endomyocardial biopsies after pediatric heart transplantation is still the most reliable parameter to detect early transplant rejection in about 11% of cases. Using routine endomyocardial biopsy as a close monitoring of cardiac allograft rejections might improve posttransplant outcome in pediatric patients with a low periprocedural risk profile. However, further randomized prospective studies using concise definitions of transplant rejections screening in children are needed.