Incidence and Risk Factors for Mortality in Infants Awaiting Heart Transplantation in the USA

Abstract

Infants awaiting heart transplantation (HT) face the highest wait-list mortality among all children and adults listed for HT in the USA. We sought to determine the risk of death for infants <12 months old while awaiting HT in the current era, and to identify the principle risk factors associated with wait-list mortality. We analyzed outcomes for all infants listed for HT in the USA from January 1999 to July 2006, using data reported to the U.S. Scientific Registry of Transplant Recipients. Of the 1,133 listed infants, 61% were <3 months of age, 80% were listed as Status 1A, 64% had a congenital heart disease (CHD) and 31% had cardiomyopathy. Of 724 infants with CHD, 25% were on prostaglandin (PG) and 27% had a history of prior surgery. By 6 months after listing, 23% died on the wait-list and 54% were transplanted. Multivariate factors associated with wait-list mortality were weight <3 kg (hazard ratio [HR] 1.4, 95% confidence interval [CI] 1.0 to 1.9), extracorporeal membrane oxygenation (ECMO) support (HR 5.6, CI 4.0 to 7.9), ventilator support (HR 2.1, 95% CI 1.6 to 2.8), CHD with PG support (HR 2.8, 95% CI 1.8 to 4.3), CHD without prior surgery (HR 2.8, 95% CI 1.9 to 3.9) and non-white race/ethnicity (HR 1.8, 95% CI 1.4 to 2.3). One in four infants listed for HT in the USA die before a donor heart can be identified. Wait-list mortality is associated with weight <3 kg, level of invasive support and CHD, but not listing status, which captures medical urgency poorly. Measures to expand infant organ donation, especially among neonates, are urgently needed.