Intraoperative Portable Ultrasound for Real-Time Graft Perfusion Assessment During CABG: A Randomized Controlled Trial

Composite of the following events: (1) operative death; (2) perioperative myocardial perfusion adverse events (including perioperative myocardial ischemia or infarction, low cardiac output syndrome); (3) severe neurological complications (including stroke or persistent postoperative neurological deficit); (4) acute kidney injury requiring temporary or permanent dialysis; (5) postoperative need for mechanical circulatory support (e.g., IABP or ECMO); (6) unplanned cardiac reoperation (excluding reoperation for bleeding alone); (7) postoperative cardiac arrest, multiple organ failure, or mechanical ventilation > 72 hours; (8) postoperative hospital stay ≥ 30 days.

Composite of the following events: (1) significantly diminished or absent flow signal in the graft by portable ultrasound; (2) new segmental wall motion abnormality in the distal myocardial territory supplied by the graft; (3) new or worsening decline in left ventricular systolic function (LVEF decrease ≥ 10% from baseline); (4) intraoperative graft repositioning, re-anastomosis, or early postoperative interventional/surgical intervention due to ultrasound-indicated graft perfusion or functional abnormality. Any one of the above events constitutes this composite endpoint.

Change from baseline over time in complete blood count parameters, including white blood cell count (×10⁹/L) and neutrophil percentage (%). Blood samples will be collected at each time point and analyzed according to standardized laboratory procedures.

Change from baseline over time in serum inflammatory markers, including C-reactive protein (CRP, mg/L), interleukin-6 (IL-6, pg/mL), and procalcitonin (PCT, ng/mL). Blood samples will be collected at each time point and analyzed according to standardized laboratory procedures.

Change from baseline over time in coagulation function, including prothrombin time (PT, seconds), activated partial thromboplastin time (aPTT, seconds), platelet count (×10⁹/L), and platelet function. Blood samples will be collected at each time point and analyzed according to standardized laboratory procedures.

Change from baseline over time in serum hepatic function markers, including alanine aminotransferase (ALT, U/L), aspartate aminotransferase (AST, U/L), lactate dehydrogenase (LDH, U/L), total bilirubin (μmol/L), and direct bilirubin (μmol/L). Blood samples will be collected at each time point and analyzed according to standardized laboratory procedures.

Change from baseline over time in serum renal function markers, including serum creatinine (μmol/L), uric acid (μmol/L), and estimated glomerular filtration rate (eGFR, mL/min/1.73m²). Blood samples will be collected at each time point and analyzed according to standardized laboratory procedures.

Change from baseline over time in serum myocardial injury and cardiac function markers, including high-sensitivity troponin T (hs-cTnT, ng/mL), B-type natriuretic peptide (BNP, pg/mL), creatine kinase (CK, U/L), and creatine kinase-MB isoenzyme (CK-MB, U/L). Blood samples will be collected at each time point and analyzed according to standardized laboratory procedures.

Intraoperative parameters including cardiopulmonary bypass time (minutes), aortic cross-clamp time (minutes), and total surgical time (minutes). Perioperative parameters including postoperative length of hospital stay (days), chest tube drainage volume (mL) and characteristics, postoperative blood transfusion requirement and volume (mL), and incidence of perioperative complications including sternal wound infection, secondary debridement, reintubation, pneumonia, and delirium.

Intraoperative portable ultrasound parameters of distal graft perfusion and myocardial perfusion, including graft flow signals. These will be compared with postoperative conventional transthoracic echocardiography or other imaging modalities to evaluate the diagnostic accuracy and consistency of intraoperative ultrasound in assessing graft patency and distal perfusion status.