(CCSP020) ACUTE KIDNEY INJURY AND RENAL RECOVERY FOLLOWING FONTAN SURGERY

Background: Acute kidney injury (AKI) is a common complication following the Fontan operation. AKI is defined as a rise in serum creatinine (SCr) of 1.5 times or more above baseline. Despite its common occurrence post Fontan, the duration and outcomes of AKI have not been previously reported. Duration of AKI has been defined as transient (reversal of SCr < 1.5 x baseline within 48 hours), persistent (SCr < 1.5 x baseline in 2 - 7 days), and acute kidney disease (SCr >1.5 x baseline after day 7). We sought to describe the incidence of and risk factors for AKI, the phenotype of renal recovery, and evaluate the impact of AKI phenotype on outcomes.

METHODS AND RESULTS: All children who underwent a Fontan at a single center between 2009-2022 were included. Data collected from electronic medical records included Fontan characteristics, vasopressor use, all measures of SCr, and post-operative outcomes. We excluded those who had no preoperative SCr within 90 days of surgery. Every postoperative SCr was collected until the time of discharge, or 30 days postoperatively, whichever came first. Logistic regression models were used to assess predictors of AKI as well as the association between AKI and outcomes. We enrolled 141 children (45% female). AKI occurred in 100 (71%) patients. First onset of AKI was most common on postoperative day (POD) 0 in 81% or POD 1 (9%). All cases of AKI occurred by POD 7. AKI duration was transient ( < 48 hours) in 77 (55%), persistent (2-7 days) in 15 (11%), >7 days in 4 (3%), and of uncertain duration in 4 (3%). Risk factors for AKI were higher preoperative indexed pulmonary vascular resistance (OR 3.9, p = 0.004) and higher postoperative inotrope score on day 0 (OR 1.13, p = 0.047). Risk factors for AKI duration >48 hours included absence of a fenestration (OR 3.43, p=0.03) and longer duration of cardiopulmonary bypass (OR 1.22 for each 15-minute increase, 95% CI 1.04, 1.43, p=0.01). Median length of stay (LOS) was 11 days (IQR 8-18) vs. 8 days (7-10) among those with vs. without AKI (p=0.001). AKI duration >48 hours was associated with longer LOS compared to transient AKI [median 18 days (9-62) versus 10 days (8-16), p=0.006] and more sternal wound infections (17% vs. 4%, p=0.049).

Conclusion: AKI after the Fontan operation is common. The occurrence and duration of AKI has significant implications for postoperative outcomes.