The role of biomarkers in cardiac surgery-associated acute kidney injury
Cardiac surgery associated-acute kidney injury (AKI) is common, affecting up to 40 % of heart surgery patients (depending on the definition used) [1]. Five to ten percent of these patients will require new renal replacement therapy, and this carries a high price in terms of morbidity, mortality and resource utilization [2]. Despite decades of successful animal research, there have been remarkably few positive human clinical trials of cardiac surgery associated-AKI prevention and treatment, and no treatment has been confirmed effective in large, multicenter randomized clinical trials [3]. Much of the problem has been attributed to delayed diagnosis - serum creatinine does not rise until 48 hours after surgery - such that by the time the diagnosis is made, it is too late to intervene. In prevention trials, lack of a clear consensus definition of AKI has hampered endpoint adjudication such that it still remains unclear which therapies may be effective, in which patient subtypes they should be used, and what is the correct time to begin and end them. The advent of a new generation of biomarkers coming hot on the heels of a consensus definition system for AKI [4] means that we may be poised to make significant advances in this area. This chapter reviews the place of existing and novel biomarkers in the diagnosis, risk stratification and prognosis of cardiac surgery associated-AKI. © 2009 Springer-Verlag New York.