Acute Kidney Injury After Cardiac Surgery

Acute kidney injury (AKI) is common after cardiac surgery. The diagnosis is based on the criteria defined by the Kidney Disease Improving Global Outcomes (KDIGO) classification: oliguria and elevation of serum creatinine. However, oliguria is not specific of AKI and elevation of serum creatinine is too late. Therefore, new methods have been developed to earlier assess the risk of AKI. Among those methods, it has been shown that the increase of urinary dosage, in the hours following the surgery, of two proteins (Tissue Inhibitor of Metallo-Protease 2 (TIMP2) and Insulin Growth Factor Binding Protein 7 (IGFBP7)) is associated with an increased risk of occurrence of AKI in patients hospitalized in intensive care unit. The Nephrocheck® test combines the urinary dosage of those two proteins TIMP2 and IGFBP7. Insofar as post-surgery low cardiac output is one curable cause of AKI, the early detection of early kidney risk allows corrective measures to stabilize hemodynamic state and thus to reduce the risk of AKI.