Study terminated early due to program discontinuation.

To evaluate the differences between serum cystatin C based estimated glomerular filtration rate (eGFRcys), serum creatinine based eGFR (eGFRcreat) and measured glomerular filtration rate (mGFR) in subjects at high risk for acute kidney injury (AKI) approximately 90 days following cardiac surgery

This is an open label, single-visit study to evaluate the relationship between mGFR and eGFR based either on serum creatinine (eGFRcreat) or cystatin C (eGFRcys) approximately 90 days following cardiac surgery. No investigational study drug will be administered.

Key Inclusion Criteria:

• Male or female, age ≥ 45 years old

• At risk for AKI following cardiac surgery on the basis of at least one of the following pre-operatively assessed risk factors:

  1. Reduced renal function
  2. Diabetes with ongoing insulin treatment
  3. Albuminuria

• Have undergone non-emergent open chest cavity cardiovascular surgeries, with use of cardiopulmonary bypass (CPB), with or without hypothermic circulatory arrest

Key Exclusion Criteria:

• Emergent surgeries, including aortic dissection, and major congenital heart defects
• Past cardiac surgery off CPB
• Have a known allergy to iohexol

Subjects who have undergone non-emergent cardiac surgery and were at high risk of developing AKI, who meet all of the Inclusion and none of the Exclusion criteria, will be eligible.