Cardiopulmonary bypass-associated acute kidney injury.

A PPROXIMATELY 300,000 patients undergo cardiac surgical procedures each year in the United States. More than 80% of routine cardiac surgical procedures are performed using cardiopulmonary bypass (CPB). Acute kidney injury (AKI; previously referred to as acute renal failure) after CPB is a well-known, yet incompletely understood, entity that has significant implications on both shortand long-term outcomes. The development of AKI after CPB is associated with a significant increase in infectious complications, an increase in length of hospital stay, and greater mortality when compared with patients without AKI-CPB. The incidence of AKI-CPB averages 20–30%, depending on the definition used and the duration of the postoperative period studied. Furthermore, more patients with AKI-CPB who require dialysis remain dialysis dependant. For all patients undergoing CPB, the risk of AKI-CPB is the least in those who undergo coronary artery bypass grafting (CABG) only; the risk increases for patients undergoing valve replacement surgery; and the risk is the greatest after combined CABGvalve procedures. There has not been a significant reduction in mortality, despite many recent advances in our understanding of the causative pathophysiology and pharmacotherapeutics of AKI-CPB. Furthermore, advances in renal replacement therapies (RRTs) have not significantly altered the overall mortality associated with AKI-CPB. In this review, we will focus on the current definitions of AKI, pathophysiologic features, and risk factors for developing AKI-CPB. We will also discuss perioperative strategies and emerging concepts that add to our understanding of this complex entity to help better manage patients at risk for AKI-CPB.