Acute kidney injury after heart transplant in young children: risk factors and outcomes

Background Critical illness following heart transplantation can include acute kidney injury (AKI). Study objectives were to define the epidemiology of, risk factors for, or impact on outcomes of AKI after pediatric heart transplant. Methods Using data from a prospective study of 66 young children, we evaluated: (1) post-operative AKI rate (by pediatric modified RIFLE criteria); (2) pre, intra, and early post-operative AKI risk factors using stepwise logistic regression (3) effect of AKI on short-term outcomes (ventilation and length of pediatric intensive care unit (PICU) stay) using stepwise multiple regression. Results AKI occurred in 73 % of children. Pre-transplant ventilation and higher baseline estimated creatinine clearance (eCCl) were independent risk factors for AKI. Pre-operative inotrope use was associated with reduced risk of AKI. Tacrolimus level emerged as important in multivariable risk prediction. Children with AKI had a longer duration of ventilation and length of pediatric intensive care unit (PICU) stay, with AKI being an independent predictor. Conclusions AKI was common after heart transplant and associated with more complicated early post-transplant course. Lower baseline eCCl was associated with lower incidence of AKI; this merits further investigation. The association of pre-operative inotropes with less AKI may reflect a pathophysiological mechanism or be a surrogate for clinical factors and management prior to transplant. Avoiding high tacrolimus levels may be a modifiable risk factor for AKI.