This study focuses on preventing Acute Kidney Injury, which is a sudden episode of kidney failure or damage that happens or develops within a short period of time. The research is specifically looking at patients at high risk for this condition following Cardiac Surgery, such as procedures involving the heart valves, the aorta, or a Coronary Artery Bypass Graft. These surgeries often require the use of a Cardiopulmonary Bypass machine, which is a device that temporarily takes over the function of the heart and lungs during the operation.

The purpose of the study is to evaluate the safety and effectiveness of a drug called R2R01. This medication is a Relaxin Agonist, which is a type of substance designed to activate specific proteins in the body to achieve a therapeutic effect. During the study, participants will receive either R2R01 or a placebo containing Sodium Chloride via a subcutaneous injection, which is an injection given into the fatty tissue just under the skin.

Participants will be assigned to different groups to receive different doses of the medication or the placebo. The study is double-blind, meaning that neither the participants nor the medical staff know which substance is being administered. The course of the study involves monitoring the participants after their surgery to observe how their kidneys function and to track any side effects that may occur.