Intraoperative Ultrasound Assessment of Coronary Artery and Bypass Graft Blood Flow During CABG

This single-centre, prospective observational feasibility and safety study will enrol 190 consecutive adults undergoing elective isolated coronary artery bypass grafting (CABG) at Nanjing Drum Tower Hospital. The study aims to evaluate the feasibility and safety of intraoperative ultrasound for the quantitative assessment of native coronary artery and bypass graft blood flow. Transit-time flow measurement will be performed as part of routine intraoperative graft assessment. Additional ultrasound measurements will be obtained from major native coronary arteries before and after revascularisation and from bypass grafts after restoration of blood flow. The ultrasound findings will be collected for research purposes and will not influence graft revision or other intraoperative clinical decisions. The co-primary outcomes are the participant-level technical success rate of the protocol-defined intraoperative ultrasound assessment and the incidence of adverse events related to the ultrasound device or measurement procedure. Secondary outcomes include agreement between ultrasound and transit-time flow measurements, changes in native coronary artery blood flow after revascularisation, measurement repeatability, and exploratory associations between intraoperative flow parameters and postoperative cardiac function and myocardial injury biomarkers. Participants will be followed for 30 ± 7 days after surgery.