Novel Biomarkers for Cardiac Surgery-Associated Acute Kidney Injury: A Skeptical Assessment of Their Role

Cardiac surgery-associated acute kidney injury (AKI) is common and is associated with a high mortality rate. Traditional biomarkers of AKI (creatinine and urea) increase slowly in response to renal injury, are insensitive to mild degrees of AKI, and are influenced by nonrenal factors. There is considerable interest in novel biomarkers of AKI such as neutrophil gelatinase-associated lipocalin that increase rapidly after renal injury, detect mild degrees of AKI, and are less subject to nonrenal factors. It has been postulated that the early diagnosis of cardiac surgery-associated AKI using novel biomarkers
will result in improved outcomes. However, there is little evidence
that interventions started early in the course of evolving AKI enhance
renal recovery. Until effective therapies are developed that
significantly improve the outcome from AKI, there is little benefit from
early diagnosis using novel biomarkers.