Nicotinamide Mononucleotide in Patients Undergoing Cardiac Surgery

Inclusion Criteria: 1. Age ≥18 years 2. Scheduled to undergo elective isolated CABG surgery and/or valve surgery with cardiopulmonary bypass (CPB) 3. At increased risk of postoperative complications based on ≥1 of the following: 1. Age ≥65 years 2. eGFR \<45 ml/min/1.73m2 3. Documented history of congestive heart failure or left ventricular ejection fraction (LVEF) ≤40% within 6 months before surgery 4. Diabetes mellitus 5. Proteinuria defined as urine albumin-to-creatinine ratio \>30 mg/g creatinine, urine protein-to-creatinine ratio \>0.05g/g creatinine, or 2+ or greater proteinuria on a urinalysis 6. Peripheral arterial disease 7. Anemia, defined as hemoglobin \<10 g/dl 8. Prior cardiac surgery Exclusion Criteria: 1. Any of the following laboratory abnormalities at the time of screening: 1. ALT \>3-fold the upper limit of normal 2. eGFR \<30 ml/min/1.73m2 or ESKD on dialysis 3. Hemoglobin \<8 g/dl 2. History of malabsorption 3. Active alcohol abuse or illicit substance use in the prior 6 months 4. Participation in an investigational trial to evaluate pharmaceuticals or biologics within the past 3 months or 5 half-lives, whichever is shorter 5. Pregnant or breast-feeding 6. Unwillingness to use contraception while taking study drug and for 8 weeks after the last dose for women of reproductive age or non-sterilized male participants who are sexually active with a female partner of childbearing potential 7. Current use of niacin \>100 mg/day or NMN, nicotinamide, or nicotinamide riboside at any dose 8. Conflict with other research studies 9. Any condition which, in the judgement of the investigator, might increase the risk to the participant