Development of postoperative acute renal failure (ARF) increases the mortality after cardiac surgery to 50%.
Previous attempts at therapeutic interventions have failed, and the survival rate associated with ARF remains dismal. It has become exceedingly evident that renal failure complicating major procedures has a modifying effect on overall outcome and is not a mere indicator of the patient’s illness.
The Cleveland Clinic ARF score, developed and validated in our institution, has been a powerful bedside tool for patient counseling as well as an important research tool. But while the ARF score has the ability to predict kidney failure that will require dialysis, recent reports have shown that even mild-to-moderate renal impairment has far-reaching survival implications.
We are now studying models that predict the slightest changes in renal function in the perioperative period. These models would translate to a more precise and useful tool for counseling patients about to undergo major cardiac surgery.
By focusing our investigation on patients who are at high risk, we are currently evaluating the role of new promising biomarkers, such as neutrophil gelatinase-associated lipocalin (NGAL), for earlier diagnosis and recognition of serious kidney injury.
Traditional markers, such as serum creatinine, have been the Achilles heel in the diagnosis and secondary intervention of ARF because of inherent delays of at least 48 hours in estimating extent of injury. We are assessing the relationship of new biomarkers with the gold standard, iothalamate glomerular filtration rate.