[Analysis of pediatric heart transplantation supported by extracorporeal membrane oxygenation]

Objective: To summarize the clinical characteristics of patients with end-stage heart failure who receive heart transplant under extracorporeal membrane oxygenation (ECMO) support. Methods: The clinical data of 12 pediatric patients who received heart transplant with ECMO support in the Seventh Medical Center of Chinese People's Liberation Army General Hospital and Guangdong Provincial People's Hospital, from January 2019 to December 2023 was collected. The data included sex, age, weight, diagnosis, pre-ECMO lactate level, left ventricular ejection fraction (LVEF), vasoactive-inotropic score (VIS), and preoperative ECMO running time. Surgical data included cold ischemia time of the donor heart, cardiopulmonary bypass time, intraoperative use of immunosuppressant, postoperative use of ECMO, duration of postoperative ECMO, rate of successful weaning from ECMO, and survival discharge rate. The paired t-test was performed to compare cardiac function indices before and after left ventricular decompression. Results: The 12 patients ranged in age from 1.1 to 15.8 years, and weighted from 8 to 63 kg. Ten children were diagnosed with dilated cardiomyopathy, one with myocardial underdensification, and one with a novel heterozygous mutation of the SCN5A gene causing overlap syndrome complicated by fatal arrhythmia. Before ECMO, the lactate ranged from 0.6 to>15.0 mmol/L, the LVEF from 6.5% to 43%, and VIS from 3 to 108. Four patients underwent left ventricular decompression supported by preoperative ECMO, and their pulse pressure was significantly increased after decompression ((17.8±2.1) vs. (9.8±1.5) mmHg, 1 mmHg=0.133 kPa, t=11.31, P=0.001), while there was no apparent change in LVEF ((26.8±4.4)% vs. (24.9±4.9)%, t=1.75, P=0.178). A total of 7 children received a second run of ECMO after surgery and 3 of them successfully weaned off ECMO and survived to discharge. In the entire cohort, 10 were successfully weaned from ECMO and 8 survived to discharge. Conclusions: For children with end-stage heart failure supported by ECMO, left ventricular decompression can significantly improve pulse pressure. These patients will eventually require heart transplantation.