Although its utility is considered to be highest in patients undergoing valvular and complex open great-vessel/ aortic surgery, it is commonly used in subjects undergoing CABG. TEE is most often used,146 although epicardial and epiaortic imaging, performed under aseptic conditions, allows visualization of imaging planes not possible with TEE.147,148 specifically, epiaortic imaging allows visualization of the blind spot of the ascending aorta (caused by interposition of the trachea with the esophagus), the site of aortic cannulation for CPB, from which dislodgement of friable atheroma, a major risk factor for perioperative stroke, may occur (Section 5.2.1). In addition, epicardial probes allow imaging when TEE is contraindicated, cannot be performed, or produces inadequate images. It can facilitate the identification of intraventricular thrombi when TEE images are equivocal. The 2003 ACC/AHA/ASE Guideline Update for the Clinical Application of Echocardiography based its recom- mendations on those reported in the 1996 American Society of Anesthesiologists/Society of Cardiovascular Anesthesiol- ogists practice guideline and considered the use of TEE in CABG patients.149 The latter document was updated in 2010.139 Because of the use of different grading methodolo- gies in the American Society of Anesthesiologists/Society of Cardiovascular Anesthesiologists guideline relative to that of the ACCF/AHA, precise comparisons are difficult. However, it is noted that TEE should be considered in subjects undergoing CABG, to confirm and refine the preoperative diagnosis, detect new or unsuspected pathology, adjust the anesthetic and surgical plan accordingly, and assess the results of surgery. The strongest recommendation is given for treatment of acute life-threatening hemodynamic instability that has not responded to conventional therapies. Observational cohort analyses and case reports have sug- gested the utility of TEE for diagnosing acute life-threatening hemodynamic or surgical problems in CABG patients, many of which are difficult or impossible to detect or treat without direct imaging. 