Current strategies for AKI detection rely primarily on elevations in serum creatinine in conjunction with diminished urine output. Unfortunately, deviations in these crude parameters of renal function are largely insensitive and late manifestations of AKI, where acute tubular necrosis has likely already transpired and therefore well beyond the phase where preventive measures may be instituted. Early phase biomarkers, insulin-like growth factor-binding protein 7 ("IGFBP7") and tissue inhibitor of metalloproteinases-2 ("TIMP-2") are critical mediators of G1 cell cycle arrest of renal tubular cells during the early phase of cellular injury, providing a potential therapeutic window to prevent permanent damage. To date, no study has evaluated the efficacy of these early phase renal biomarkers for detecting AKI in advanced heart failure patients undergoing cardiac replacement therapies.