ARTEMIS: Ravulizumab to Protect Patients With CKD From CSA-AKI and MAKE

Inclusion Criteria: * Participant weighs ≥ 30 kg * Planned non-emergent sternotomy with CPB procedure for the following surgeries: * Multi-vessel CABG * Valve replacement or repair; ascending aorta surgery permitted if combined with aortic valve replacement/repair * Combined CABG and valve surgery; inclusion of single-vessel CABG when combined with valve replacement/repair is permitted * Known CKD for at least 90 days (CKD Stage 3A, 3B, or 4) Exclusion Criteria: * Emergency or salvage cardiac surgery is expected at screening or randomization, as assessed by the investigator. * Single-vessel CABG without valve surgery is planned. * Off-pump surgery is planned (eg, surgery without CPB). * Recipient of a solid organ or bone marrow transplantation. * Cardiogenic shock, hemodynamic instability, use of intra-aortic balloon pump, extracorporeal membrane oxygenation, or left ventricular assist device within 72 hours of randomization. * Active systemic bacterial, viral, or fungal infection within 14 days prior to randomization. * History of unexplained, recurrent infection. * Any use of KRT or presence of AKI within 30 days of randomization * Use of any complement inhibitors, or plasmapheresis or plasma exchange within the year prior to Screening, or planned use during the course of the study. * Participant is not willing to be vaccinated against N meningitidis or is unwilling to receive prophylactic treatment with appropriate antibiotics , if needed * History of or unresolved N meningitidis infection.