Inclusion Criteria:

• Male or female.
• Age > 18 years old.
• Patients who match the criteria for indication of elective open aortic arch replacement or repair:
  • Total arch;
  • Non-total arch.
• Patients who match the criteria for indication of elective complex aortic aneurysm repair has to respect the following conditions:
  • Patients undergoing complex aortic aneurysm open reconstruction with a suprarenal clamp:
    • thoracoabdominal aortic aneurysms Crawford extent I to IV;
    • abdominal aortic aneurysms of juxtarenal, pararenal, or paravisceral type.
  • For endovascular approach:
    • patients with pararenal or thoracoabdominal aortic aneurysms Crawford extent I to IV and known stage III or IV CKD;
    • patients with pararenal or thoracoabdominal aortic aneurysms Crawford extent I to IV and solitary or single functioning kidney and known stage III or IV CKD.
• Patients will be allowed to participate in concomitant endovascular aortic stent-graft trials and prospective cohort studies as long as these do not involve another investigational study drug.

General Exclusion Criteria:

• Unwilling to comply with the follow-up schedule.
• Inability or refusal to give informed consent by the patient or a legally authorized representative.
• Pregnant or breastfeeding.
• Subject who takes multivitamins containing vitamin B3 derivatives in a dose > 200 mg/day.

Clinical / Laboratory Exclusion Criteria:

• Renal failure defined as eGFR< 15 mL/min/1.73m2.
• Patients in permanent Renal Replacement Therapy.
• Patients with chronic liver disease: Child-Pugh score class B and C.

Medication Exclusion Criteria:

• Patients in chemotherapy scheme.
• Patients taking any immunosuppressant, except for corticosteroids.
• Patients taking any of these well-known P-glycoprotein substrates: digoxin, fexofenadine, indinavir, sirolimus.
  • For some types of P-glycoprotein substrates, subjects will be closely monitored.