Aortic No-Touch vs Partial Aortic Clamping in Off-Pump CABG

Inclusion Criteria: * Adult patients (\>18 years old) with multivessel coronary artery disease who are scheduled to undergo isolated off-pump coronary artery bypass grafting and who provide informed consent to participate in this study. Exclusion Criteria: * Indications for cardiopulmonary bypass surgery (or no contraindications to on-pump surgery); * Great saphenous vein is unsuitable for use as a graft conduit; * Subclavian artery stenosis or occlusion, or any contraindication to the use of the internal mammary artery as a graft conduit; * History of previous cardiac surgery; * Emergency surgery; * Inability to apply an aortic clamp due to severe ascending aortic calcification; * Expected inability to tolerate MRI or contraindications to MRI (e.g., known intolerance to MRI, an implanted permanent pacemaker, or an anticipated need for permanent pacemaker implantation); * Inability to complete neurocognitive assessment due to language barriers or visual/hearing impairment.