Perioperative myocardial injury (PMI) following coronary artery bypass grafting (CABG) is associated with postoperative morbidity, mortality, and long-term outcomes. High-sensitivity troponin assays and cardiac MRI offer reliable diagnostic tools for PMI, but evidence regarding optimal diagnostic thresholds and perioperative imaging strategy is limited. This prospective clinical study aims to determine the incidence of perioperative myocardial injury using multimodal assessments including high-sensitivity troponin, electrocardiogram, echocardiography, cardiac MRI, and perioperative cardiovascular events.

Inclusion Criteria:

1. Age ≥ 21 years
2. Undergoing CABG for unstable angina
3. Able to provide written informed consent
4. No major cardiovascular event in the prior 6 months

Exclusion Criteria:

1. Significant hepatic, renal, or other major organ dysfunction
2. Pregnancy or breastfeeding
3. Withdrawal during the study
4. Contraindication to cardiac MRI (metal implants, claustrophobia, etc.)

Adult patients diagnosed with unstable angina and scheduled to undergo isolated coronary artery bypass grafting (CABG) at the Second Hospital of Jilin University. All participants receive routine perioperative clinical evaluations. The study includes patients aged 21 years or older who provide written informed consent and have had no major cardiovascular events within the previous 6 months. Patients with severe organ dysfunction, pregnancy, or contraindications to cardiac MRI are excluded.