Incidence, Predictors, and Impact of Postoperative Acute Kidney Injury Following Fontan Conversion Surgery in Young Adult Fontan Survivors

Acute kidney injury (AKI) is a common complication following single ventricle congenital heart surgery. Data regarding AKI following Fontan conversion (FC) surgery are limited. This study evaluated the incidence, predictors of, and prognostic value of AKI following FC. Single-center retrospective cohort study, including consecutive FC patients from December 1994 to December 2016. Medical records were reviewed. AKI was classified into AKI-1/AKI-2/AKI-3 using Kidney Disease: Improving Global Outcomes criteria. Multivariable logistic regression identified risk factors for AKI≥2. Chi-square and 2-sample t-tests assessed associations between AKI≥2 and postoperative outcomes. Mid-term heart-transplant-free survival among AKI0-1 vs AKI2-3 groups was compared using Kaplan-Meier curves and log-rank test. We included 139 FC patients: age at FC 24 (25th–75th, 19–31) years; 81% initial atrio-pulmonary Fontan; follow-up 8.3 ± 5.3 years following FC. Post-FC, 63 patients (45%) developed AKI (AKI-1 = 37 [27%]; AKI-2 = 10 [7%]; AKI-3 = 16 [11%]). AKI recovered by hospital discharge in 86%, 80%, and 19% of patients with AKI-1/AKI-2/AKI-3, respectively. Independent risk factors for AKI≥2 included older age (OR 1.07, 95%CI 1.01–1.15; P = 0.027); ≥3 prior sternotomies (OR = 6.11; 95%CI = 1.59–23.47; P = 0.009); greater preoperative right atrial pressure (OR 1.19; 1.02–1.38; P = 0.024), and prior catheter ablation procedure (OR 3.45; 1.17–10.18; P = 0.036). AKI≥2 was associated with: longer chest tube duration (9 [5–57] vs 7 [3–28] days; P = 0.01); longer mechanical ventilation time (2 [1–117] vs 1 [1–6] days; P = 0.01); greater need for dialysis (31% v s0%; P < 0.001); and longer postoperative length of stay (18 [8–135] vs 10 [6–58] days; P < 0.001). AKI 2–3 patients had worse mid-term heart-transplant-free survival. Half of the patients undergoing FC develop AKI. AKI 2–3 is associated with worse early postoperative outcomes and reduced mid-term transplant-free survival following FC. Knowledge of AKI predictors may allow for improved FC risk stratification, patient selection, and perioperative management in this high-risk population.