Change in right ventricular function during off-pump coronary artery bypass graft surgery

Objectives: Hemodynamic derangement during displacement of beating heart in off-pump coronary artery bypass graft (OPCAB) surgery might be related with right ventricular (RV) dysfunction. We evaluated RV function and hemodynamic alterations using a thermodilution pulmonary artery catheter. Methods: The study included 30 patients undergoing OPCAB, using single pericardial suture and tissue stabilizer. A thermodilution pulmonary artery catheter for continuous monitoring of the cardiac output (CO), right ventricular ejection fraction (RVEF) and RV volume was inserted before anesthesia. The hemodynamic variables were measured after the induction of anesthesia, 5 min after the heart was positioned for each coronary anastomosis and after the sternum was closed. Results: There was no significant change in the RVEF and cardiac index during anastomosis of the left anterior descending artery and right coronary artery. However, the significantly reduced RVEF accompanied by an increase in RV afterload and decrease in the CO was observed during anastomosis of the obtuse marginal (OM) artery. RV volumes did not significantly change during anastomoses, though the right atrial pressure increased during anastomoses of all coronary arteries. Conclusions: The displacement of beating heart for positioning during anastomosis of the graft to OM artery caused significant derangement of RV function and decrease in CO. A thermodilution catheter continuously measuring the CO and RVEF was useful to monitor the change in RV function and volume during OPCAB.