The impact of mechanical circulatory support on outcomes in paediatric heart transplantation

Internationally, the number of donors for cardiac transplantation has remained static, while the number of patients requiring transplantation for congenital heart disease (CHD) has increased. Although the availability of mechanical circulatory support (MCS) may increase the number of transplants performed by reducing deaths while waiting, it may also lead to increased morbidity post-transplantation. We sought to assess the impact of mechanical support on post-transplant outcomes in a single centre. We assessed the outcomes of paediatric (age < 16 years) heart transplantation in a single unit in the era of mechanical support (1998-2012) by retrospective cohort study. Outcomes before (1998-2005) and after (2005-2012) the routine use of the Berlin Heart EXCOR device were contrasted. A total of 167 patients underwent heart transplantation during this period. The diagnosis was dilated cardiomyopathy in 61.7%, two-ventricle CHD in 11.4%, single ventricle CHD in 16.8% and miscellaneous in 10.1%. Sixty-nine (41%) were bridged to transplant by mechanical support; with extracorporeal membrane oxygenation in 19 (28%), ventricular assist device in 40 (58%) and a combination in 10 (14.0%). Post-transplant mortality at 30 days was significantly greater in those supported by MCS than without (7 vs 1%, P < 0.05), and a greater proportion of patients had neurological (23 vs 8%, P < 0.01) and major respiratory sequelae (20 vs 4%, P < 0.001). There was no significant increase in the need for post-transplant mechanical support (10 vs 6%, P = 0.3) in those supported prior to transplant. The number of transplants performed increased from 67 in 1998-2005 to 100 in the most recent era (2005-2012), and an increased proportion of these patients have been supported mechanically prior to transplantation (51 vs 27%, P < 0.01). Along with strategies to increase donor utilization, MCS has allowed an increase in cardiac transplant activity at the expense of a higher early mortality and morbidity.