Markers and predictors of renal outcome after cardiac surgery

Acute renal dysfunction remains a serious complication of cardiac surgery, even when dialysis is not required, that is strongly associated with short and long term mortality and increased resource utilization. Although difficult to study in the critically ill patient, it is presumed that remote effects of acute renal injury contribute significantly to the overall poor prognosis typical of conditions that inflict renal insult (e.g., sepsis). Normally the kidney plays a central role in maintaining homeostasis; animal studies are uncovering the important consequences of acute derangements of renal function on other organs, some of which are being attributed to accumulation of "uremic toxins". While research is shedding light on the role of the kidney in adverse outcome after cardiac surgery, there is continued disappointment in the search for renoprotective therapies useful to prevent or treat acute renal injury. Better understanding of renal risk factors through research remains key in clinical decision-making to protect the kidney. A profile of patient and procedural characteristics is now available that identifies both the vulnerable kidney, and factors that contribute to the three major mechanisms of perioperative renal insult-ischemia-reperfusion injury, inflammation and toxin exposure. Unfortunately, research tools are suboptimal and progress is hampered in part by disagreement over appropriate measures of renal dysfunction. Although peak creatinine rise provides less reliable estimates of glomerular filtration during the perioperative period, no other renal marker has been more validated as a predictor of outcome in the surgical patient, and each of the many other available methods also have limitations, some of them unique to the cardiac surgical patient. Future possibilities include preoperative genetic testing to identify the vulnerable kidney, and better understanding of the role of stem cells in perioperative acute renal injury. Copyright © 2005 JMS.

Duke Scholars

Author Mark Stafford-Smith Anesthesiology, Cardiothoracic