ABSTRACT
Retraction and stabilization of the heart can induce rapid and large changes in the hemodynamic state during off-pump coronary artery bypass graft surgery (OPCABG). We aimed to determine if Doppler measurement of flow in the descending artery with transesophageal echocardiography (TEE) can provide a beat-to-beat assessment of changes in cardiac output (CO) in 26 OPCABG patients. Simultaneous measurements were performed of CO using thermodilution, and descending aortic flow (FlowDA) with TEE, prior to grafting, and during grafting to the left anterior descending artery (LAD), circumflex (Cx) and right coronary artery (RCA) territories. CO decreased from baseline (SD) values of 6.2 (1.7), to 5.4 (1.8) L/min during grafting to the LAD, 4.4 (1.5) L/min to the Cx territory, and 4.4 (1.4) L/min to the RCA territory (P<0.001). There was poor correlation between CO and FlowDA between individuals. In a subgroup of 16 patients who had grafts to all territories, the changes in Flow(DA), occurred in the same direction and magnitude as changes in CO (P = 0.062, RM-ANOVA for factor*time interaction). Doppler assessment of flow in the descending aorta is able to track changes in CO during OPCABG. (Ann Thorac Cardiovasc Surg 2003; 9: 314-8)
