Performance of kidney injury molecule-1 and liver fatty acid-binding protein and combined biomarkers of AKI after cardiac surgery

Abstract

Background and objectives: AKI is common and novel biomarkers may help provide earlier diagnosis and prognosis of AKI in the postoperative period.

Design, setting, participants, & measurements: This was a prospective, multicenter cohort study involving 1219 adults and 311 children consecutively enrolled at eight academic medical centers. Performance of two urine biomarkers, kidney injury molecule-1 (KIM-1) and liver fatty acid-binding protein (L-FABP), alone or in combination with other injury biomarkers during the perioperative period was evaluated. AKI was defined as doubling of serum creatinine or need for acute dialysis.

Results: KIM-1 peaked 2 days after surgery in adults and 1 day after surgery in children, whereas L-FABP peaked within 6 hours after surgery in both age groups. In multivariable analyses, the highest quintile of the first postoperative KIM-1 level was associated with AKI compared with the lowest quintile in adults, whereas the first postoperative L-FABP was not associated with AKI. Both KIM-1 and L-FABP were not significantly associated with AKI in adults or children after adjusting for other kidney injury biomarkers (neutrophil gelatinase-associated lipocalin and IL-18). The highest area under the curves achievable for discrimination for AKI were 0.78 in adults using urine KIM-1 from 6 to 12 hours, urine IL-18 from day 2, and plasma neutrophil gelatinase-associated lipocalin from day 2 and 0.78 in children using urine IL-18 from 0 to 6 hours and urine L-FABP from day 2.

Conclusions: Postoperative elevations of KIM-1 associate with AKI and adverse outcmes in adults but were not independent of other AKI biomarkers. A panel of multiple biomarkers provided moderate discrimination for AKI.

Figure 1.

Biomarker distribution over time. AKI defined by receipt of acute dialysis or a doubling in serum creatinine during the hospital stay. Yellow bar indicates the IQR of the day to the first evidence of AKI in patients with AKI. Blue and green bars represent the IQR (25th and 75th percentiles for AKI and non-AKI patients, respectively). The solid lines denote the median values. Day 1 is the day of surgery, with time 0 representing the point when the patient arrived in the postoperative ICU. *P<0.05 for comparison of AKI and non-AKI. KIM-1, kidney injury molecule-1; L-FABP, liver fatty acid-binding protein; IQR, interquartile range.