Postoperative Acute Kidney Injury in Cardiac Surgery

Acute kidney injury (AKI) is a significant cause of morbidity and mortality among hospitalized patients, especially in the postoperative setting. In addition, it remains a significant complication of cardiac surgery throughout the world. Consequences of AKI include an increase in mortality risk that can exceed 60% among patients requiring dialysis. Even when serum creatinine values remain within the normal range, modest increases from baseline values are associated with higher odds of death and end-stage renal disease, as well as longer hospital stays and increased costs. The presence of multiple patient-related risk factors in the cardiac surgery population adds to unique intraoperative and procedurerelated factors, making this group of patients particularly vulnerable to the adverse effects of an acute renal insult. In general, there have been no improvements in incidence or mortality despite many recent advances in our understanding of the etiology and pathophysiology of AKI. Although the phenomenon of postoperative renal injury has been recognized for many decades, its definitions have continually evolved as its significance to outcomes has emerged. Multiple definitions initially hampered efforts at comparing results from different studies. However, with new consensus on a uniform definition of AKI, there are hopes for not only establishing the importance of this complication, but also for evaluating new biomarkers and assessing the effectiveness of preventive and therapeutic interventions in a universally acceptable manner.