Objectives: The noninvasive monitoring of thoracic aortic blood flow (TABF) during off-pump coronary artery bypass (OPCAB) surgery is becoming more commonly used and proved to be invaluable in the early detection of hemodynamic compromise due to heart displacement. The aim of this study was to analyze the changes in TABF during OPCAB using transesophageal Doppler and compare them with the changes observed by other monitoring methods such as cardiac output, invasive pulmonary and radial pressures and mixed venous oxygen saturation; and to study the effect of dobutamine on optimizing cardiac hemodynamics perioperatively.Methods: The measurements obtained from classic hemodynamic monitoring methods including the radial arterial line and the pulmonary artery catheter with continuous monitoring of the cardiac output and mixed venous blood oxygen saturation were compared to the measurements of TABF obtained from transesophageal Doppler probe in 32 consecutive patients who underwent OPCAB surgery.Results: The TABF decreased significantly during the construction of coronary anastomoses and returned to the baseline values at chest closure. The cardiac output measurements showed no significant decrease compared to baseline. There was an amelioration of cardiac hemodynamics with the use of minimal doses of dobutamine.