Peri-operative heart-type fatty acid binding protein is associated with acute kidney injury after cardiac surgery

Acute kidney injury (AKI) is a common complication after cardiac surgery and is associated with worse outcomes. Since heart fatty acid binding protein (H-FABP) is a myocardial protein that detects cardiac injury, we sought to determine whether plasma H-FABP was associated with AKI in the TRIBE-AKI cohort; a multi-center cohort of 1219 patients at high risk for AKI who underwent cardiac surgery. The primary outcomes of interest were any AKI (Acute Kidney Injury Network (AKIN) stage 1 or higher) and severe AKI (AKIN stage 2 or higher). The secondary outcome was long-term mortality after discharge. Patients who developed AKI had higher levels of H-FABP pre- and postoperatively than patients who did not have AKI. In analyses adjusted for known AKI risk factors, first postoperative log(H-FABP) was associated with severe AKI (adjusted odds ratio (OR) 5.39 (95% confidence interval (CI), 2.87-10.11) per unit increase), while preoperative log(H-FABP) was associated with any AKI (2.07 (1.48-2.89)) and mortality (1.67 (1.17-2.37)). These relationships persisted after adjustment for change in serum creatinine (for first postoperative log(H-FABP)) and biomarkers of cardiac and kidney injury, including brain natriuretic peptide, cardiac troponin-I, interleukin-18, liver fatty acid binding protein, kidney injury molecule-1, and neutrophil gelatinase-associated lipocalin. Thus, perioperative plasma H-FABP levels may be used for risk stratification of AKI and mortality following cardiac surgery.