Clinical Research Directory

Inclusion Criteria: 1. Age ≥18 years 2. Undergoing coronary artery bypass graft (CABG) and/or valve surgery with cardiopulmonary bypass (CPB) at BIDMC. Includes combination surgeries that involve CABG and/or valve plus other procedures (e.g., Maze procedure, aortic aneurysm repair). 3. AKI risk score ≥6 at the time of screening Exclusion Criteria: 1. History of AKI in the seven days prior to surgery, defined as any of the following: * Increase in serum creatinine ≥0.3 mg/dl in 48h * Increase in serum creatinine ≥50% in 7d (if no value available in last 7d, use most recent value in last 3 months) * Urine output ≤0.5 ml/kg/h x 6 consecutive hours (only assessed in patients with hourly monitoring via Foley catheter) * Receipt of renal replacement therapy (RRT) within 7d 2. Advanced chronic kidney disease (eGFR \<15 ml/min/1.73m2 or end-stage kidney disease receiving RRT) 3. Pregnant or breastfeeding\* 4. Positive COVID test in the last 10 days. 5. Prisoner or institutionalized 6. Existing or anticipated durable VAD 8\. Conflict with other studies 9\. Previous usage of nicotinamide supplements in the past 30 days