Predictors of outcomes in children awaiting heart transplantation: an experience from a National Paediatric Heart Transplantation Programme.

Abstract

The risk of mortality while awaiting heart transplantation (HT) may be greater in the setting of a smaller population and lower donor organ rates. Optimizing allocation policy and identifying the most vulnerable patients will help reduce mortality. As such, we aimed to evaluate the predictors of outcomes in patients awaiting HT as part of a National Paediatric HT Programme. Between 1988 and 2015, 200 children were listed for HT as part of a National Paediatric HT Programme. We categorized patients as experiencing one of four competing events: (i) transplant, (ii) death, (iii) delisting for clinical deterioration and (iv) delisting for clinical improvement. Comparison was made across three study eras: Era 1: 1988-95; Era 2: 1996-2005; Era 3: 2006-15. A multivariable competing risk regression analysis was performed to determine the independent predictors of transplantation and the composite event of death or delisting for clinical deterioration. Among the 200 patients listed, 60% (119/200) underwent transplantation, 22% (44/200) died on the waiting list, 7% (13/200) were delisted for clinical deterioration and 11% (21/200) were delisted due to clinical improvement, with 2% (3/200) being still active on the waiting list. The mortality-rate for patients who remained on the waiting list decreased from 27% in Era 1 to 18% in Era 3. The survival from wait-listing was 57, 47 and 39% at 5, 10 and 15 years, respectively. On multivariable competing risk regression, older age (HR 1.09, 95% CI 1.01-1.18, P = 0.029) and the absence of inotropic support (HR 2.22, 1.23-4.00, P = 0.0073) were predictors of reaching transplantation. Higher creatinine (per 20 µmol/l, HR 1.42, 1.03-1.95, P = 0.03) was a predictor of the composite endpoint of death or delisting for deterioration. In this analysis of a National Paediatric HT Programme, waiting-list mortality has decreased over time though it remains higher than countries with higher donor rates. The requirement for inotropic support and worsening renal function were predictors of failure to reach transplantation. These patients are likely to benefit the most from ventricular-assist device therapy and higher priority listing.