A Phase 2b Dose Finding Study of RMC-035 in Participants Undergoing Open-chest Cardiac Surgery

The goal of this clinical trial is to identify the optimal dose of RMC-035 for protection of long-term renal function in adult patients undergoing cardiac surgery who are at high risk of kidney injury. It will also learn about the safety of RMC-035. The main question it aims to answer is: * Does RMC-035 protect the function of kidneys after surgery? * Is RMC-035 safe? Researchers will compare RMC-035 in high dose, RMC-035 in low dose and placebo to see if * Kidney function better for participants treated with any of the RMC-035 doses? * What medical problems do participants have when receiving RMC-035? Participants will * Receive 3 doses of RMC-035 or placebo: at the beginning of surgery, end of surgery and 24h after surgery * Have extra checkups and tests during their hospital stay * Visit the clinic at two extra occasions at 60 days and 90 days after surgery for checkups and tests