This study aims to find out if a new drug, RBT-1, can help reduce problems after heart surgery. Heart surgery often uses a machine called a cardiopulmonary bypass (CPB) to help circulate blood. This study also looks at how the body processes (pharmacokinetics, or PK) the drug when given once before surgery. To join, you must be at least 18 years old and planning to have heart surgery that uses CPB. Women must use birth control or not have sex unless certain conditions exempt them. Men must also use birth control or abstain from sex unless they've had a vasectomy long enough before the study. You must be willing to follow all study activities. You can't join if your surgery is too soon, if you have serious health issues like kidney disease or cancer, or if you have certain other health conditions. Pregnant or breastfeeding women cannot participate.

• The study requires drug infusion 24 to 48 hours before surgery.
• Participants need to comply with all study-related procedures.
• Excludes individuals with certain health conditions or recent investigational drug/device use.