Abbreviations
IMA: left internal mammary artery; CABG: coronary artery bypass grafting; ACCF/AHA: American College of Cardiology Foundation/American Heart Association; PSV: peak systolic velocity; PDV: peak diastolic velocity; sVTI: systolic velocity–time integral; dVTI: diastolic velocity–time integral; RI: resistance index; dVTIF: diastolic velocity–time integral fraction; D/S: peak systolic velocity/peak diastolic velocity.