Acute kidney injury after Fontan completion: Risk factors and outcomes

Abstract

Objective: Acute kidney injury (AKI) is a predictor of outcomes in heterogeneous populations of children undergoing cardiac surgery. We investigated its causes and consequences in a cohort undergoing Fontan completion, hypothesizing that central venous pressure is independently associated with development of AKI.

Methods: In this retrospective cohort study of patients undergoing Fontan (n = 211), univariable and multivariable analyses identified factors associated with AKI within 3 days of surgery. Secondary analyses identified factors associated with hospital length of stay, and examined effects of perioperative kidney injury on follow-up renal function.

Results: Acute kidney injury occurred in 42% of cases (n = 89), with the following independent risk factors: mean renal perfusion (mean arterial minus central venous) pressure on postoperative day zero (per mm Hg; adjusted odds ratio [AOR] 0.83; P < .001); preoperative atrioventricular valve regurgitation > mild (AOR 6.78; P = .02); bypass time (per 10 minutes, AOR 1.08; P = .04); peak inotrope score on postoperative day zero (per point, AOR 1.17; P < .001); and preoperative pulmonary vascular resistance (per Wood unit, AOR 1.69; P = .04). Central venous pressure was not independently associated with AKI. Moderate and severe (but not mild) AKI were independently associated with prolonged hospital length of stay (adjusted hazard ratios, 0.56; P = .004, and .41; P = .006, respectively). Perioperative injury was not associated with longer-term renal dysfunction.

Conclusions: Acute kidney injury is common after Fontan completion and has several potentially modifiable risk factors. Moderate-to-severe injury is associated with longer hospital length of stay but not with renal dysfunction at follow-up.

Keywords: Pediatrics; acute kidney injury; congenital heart disease; fontan.