Objective:
To evaluate the association of intraoperative urinary biomarker excretion during cardiac surgery and the subsequent development of acute kidney injury (AKI).
Design:
Prospective, nonrandomized, observational study.
Setting:
Single tertiary-level, university-affiliated hospital.
Participants:
90 patients undergoing cardiac surgery with cardiopulmonary bypass (CPB)
Interventions: None
Measurements and Main Results:
Urinary samples were collected every 30 minutes intraoperatively and then at 4, 12, and 24 hours after CPB. Samples were measured for interleukin-18 (IL18), kidney injury molecule-1 (KIM1), and creatine concentrations. Urinary biomarker excretion (raw and indexed to creatinine) for 4 intraoperative and 3 postoperative time points were compared between patients with versus without subsequent AKI defined by increased serum creatinine concentration ≥0.3 mg/dl within the first 48 hours or ≥1.5 times baseline within 7 days. Raw and indexed median IL18 values were similar between AKI groups at all intraoperative time points but became significantly different at 12 hours after CPB. Raw and indexed median KIM1 values were significantly different between AKI groups at multiple intraoperative time points and at 4 and 12 hours after CPB. During intraoperative and postoperative time points, patients in the fourth quartile of KIM1 excretion, had greater AKI incidence and longer intensive care and hospital length of stay (LOS) than those in the first quartile. Differences in these outcomes between the fourth and first quartile of IL18 excretion only occurred postoperatively.
Conclusion:
Intraoperative KIM1 but not IL18 excretion was associated with postoperative development of AKI.