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. Evaluation of ventricular cross-sectional areas and ejection fraction (EF) and estimation or direct measure- ment of cardiac output by TEE may facilitate anesthetic, fluid, and inotropic/pressor management. The utility of echo- cardiography for the evaluation of LV end-diastolic area/ volume and its potential superiority over pulmonary artery occlusion or pulmonary artery diastolic pressure, particularly in the early postoperative period, has been reported150,151 (Section 4.10). In subjects without preoperative transthoracic imaging, intraoperative TEE may provide useful diagnostic information (over and above that detected during cardiac catheterization) on valvular function as well as evidence of pulmonary hypertension, intracardiac shunts, or other com- plications that may alter the planned surgery. In patients undergoing CABG, intraoperative TEE is used most often for the detection of regional wall motion abnor- malities (possibly caused by myocardial ischemia or infarc- tion) and their effect on LV function. Observational studies have suggested that regional wall motion abnormalities de- tected with TEE can guide surgical therapy, leading to revision of a failed or inadequate conduit or the placement of additional grafts not originally planned. The presence of new wall motion abnormalities after CPB correlates with adverse perioperative and long-term outcomes.143 Although the initial hope that an estimation of coronary blood flow with intramyocardial contrast enhancement visu- alized by TEE would facilitate surgical intervention has not been realized, technical advances in imaging of coronary arteries and grafts may ultimately provide reliable informa- tion. At present, the evaluation of graft flow with conven- tional nonimaging handheld Doppler probes appears adequate (Section 8). 