BACKGROUND: It is important to evaluate the right ventricular (RV) function intraoperatively for optimal management of patients undergoing cardiac surgery. The clinical relevance of thermodilution method to tranesophageal echocardiography (TEE) for the measurements of RV function during off-pump coronary artery bypass surgery (OPCAB) was evaluated in this study.

METHODS: Fifty patients undergoing OPCAB were included. RV function was assessed with both thermodilution method and TEE after anesthesia induction (T1), 10 min after leg elevation (T2), 10 min after returning to the supine position (T3), 10 min after Y-graft formation started (T4), 10 min after sternum closure (T5) and 10 min after applying 5cmH₂O of positive end expiratory pressure (T6). Fractional area change (FAC) and tricuspid annular plane systolic excursion ratio (TAPSE) were measured by TEE and compared to RV ejection fraction (RVEF) measured by thermodilution technique. RV end diastolic area (EDA) derived from TEE was compared to RV end diastolic volume index (EDVI) derived from thermodilution technique.

RESULTS: There was no significant correlation between echocardiographic data and thermodilution data by linear regression analysis. However, only in patients with right coronary artery stenosis less than 90%, TAPSE and FAC were significantly correlated with RVEF (P = 0.008 and 0.01, respectively) and EDA was significantly correlated with EDVI (P = 0.013) only at T4.

CONCLUSIONS: RV performance measured by thermodilution technique did not correlate well with TEE finding in severe coronary artery disease patients. The correlation was significant during hemodynamically stable period (during Y-graft formation) in patients without severe right coronary artery disease.