Prevention of Renal Failure by Nitric Oxide in Prolonged Cardiopulmonary Bypass.

Inclusion Criteria: * Provide written informed consent * Are \> 18 years of age * Elective cardiac or aortic surgery with CPB, when the surgeon plans double valve replacement. * Stable pre-operative renal function, without dialysis. Exclusion Criteria: * Emergent cardiac surgery * Life expectancy \< 1 year * Hemodynamic instability as defined by a systolic blood pressure \<90 mmHg * Administration of ≥1 Packed Red Blood Cell transfusion in the week before surgery * X-ray contrast infusion less than 1 week before surgery * Anticipate administration of nephrotoxic agents, such as hydroxyethyl starch * Evidence of intravascular or extravascular hemolysis