Intraoperative Targeted Versus Liberal Blood Pressure Management in Patients Undergoing Off-pump Coronary Artery Bypass Grafting

The goal of this clinical trial is to learn whether two approaches to anesthesia and blood pressure management can improve care for adults having off-pump coronary artery bypass grafting (OPCAB). OPCAB is a type of heart bypass surgery performed without routinely using a heart-lung machine. The main questions this study aims to answer are: * Does keeping mean arterial pressure (MAP), a measure of average blood pressure, at 65 mm Hg or higher during surgery lower the chance of major complications or death within 30 days after surgery compared with usual clinician-directed blood pressure management? * Does remimazolam provide more stable blood pressure and heart rate than propofol when used to maintain general anesthesia during surgery? The researchers expect that targeted blood pressure management may lower the chance of major postoperative complications. They also expect that remimazolam may provide more stable blood pressure and heart rate than propofol. Researchers plan to enroll 416 adults having elective OPCAB surgery. Participants will be randomly assigned to one of four groups. Each group will receive one of two blood pressure strategies and one of two medicines for maintaining general anesthesia. Participants will: * Receive either targeted blood pressure management or usual clinician-directed blood pressure management during surgery. * Receive either remimazolam or propofol to maintain general anesthesia after the same standard anesthesia induction. * Have routine monitoring during surgery and assessments during recovery after surgery. * Complete follow-up assessments after surgery, including assessments of complications, recovery, and longer-term health. Some participants will also provide blood samples for a biomarker substudy. The study will also explore whether the effect of the blood pressure strategy differs depending on which anesthetic medicine is used.