Improvement of survival in low-weight children on the Berlin Heart EXCOR ventricular assist device support

OBJECTIVES: Publications on the paediatric Berlin Heart EXCOR ventricular assist device have revealed that low body weight <10 kg is a significant risk factor for mortality with children weighing <5 kg being at the highest risk. However, these studies are limited to implantation periods prior to 2011. Since then, progress has been made in the optimization of patient selection and management. This study investigated whether the survival of children weighing <10 kg supported with the EXCOR assist device has improved in recent years and sought to determine the risk factors for mortality. METHODS: The Berlin Heart EXCOR prospective registry (n = 1832) was retrospectively reviewed between 2000 and 2017 to compare the outcomes of different weight cohorts: A (<5 kg; n = 204), B (5-10 kg; n = 633) and C (>10 kg; n= 995) in different eras [era 1: January 2000-December 2012(n= 1089) and era 2: January 2013-June 2017 (n=743)]. RESULTS: Overall survival in groups A and B significantly increased from era 1 to era 2 (group A 51% vs 65%, P < 0.001; group B 74% vs 78%, P= 0.001), whereas it remained stable in group C (78% vs 73%). In era 2, the survival of group B was not significantly different from group C. On the multivariable analysis of children weighing <5 kg, congenital heart disease, preoperative extracorporeal life support and biventricular support were independently associated with increased mortality in era 1 [hazard ratio 2.04 (95% confidence interval 1.18-3.53); 2.44 (1.36-4.37) and 1.93 (1.11-3.34), respectively] but not in era 2. CONCLUSIONS: Paediatric EXCOR ventricular assist device therapy has significantly improved for patients weighing <10 kg. Withholding a ventricular assist device is not justified on the basis of the body weight alone.