EVALUATION OF HEPATIC VENOUS FLOW USING TRANSESOPHAGEAL ECHOCARDIOGRAPHY IN CORONARY-ARTERY BYPASS-SURGERY - AN INDEX OF RIGHT-VENTRICULAR FUNCTION

Hepatic venous flows (HVFs) were evaluated to assess right-heart function by transesophageal Doppler echocardiography in 45 patients undergoing coronary artery bypass graft (CABG) surgery. Peak velocity and time velocity integral of A-wave (reverse flow in end diastole), S-wave (forward flow in systole), V-wave (reverse flow in late systole), and D-wave (forward flow in diastole) of biphasic HVF were examined. Peak systolic-diastolic ratio (S/D) of biphasic HVF and reverse flow ratio (% reversal flow/forward flow [RF/FF]) of both biphasic and monophasic HVF also were examined. Tricuspid regurgitation (TR) was assessed by color Doppler image. All data were obtained after performing the following: induction of anesthesia (stage 1); pericardiectomy (stage 2); cardiopulmonary bypass (CPB) (stage 3); and closure of sternum (stage 4). HVFs at stage 1 were obtained in all 45 patients, and the peak S/D in patients with a history of inferior wall myocardial infarction (MI) was significantly less than that in patients without a history of MI (p < 0.05). HVFs of 35 patients were recorded successfully at all stages. In 5 of these 35 patients, HVF patterns became monophasic after CPB, and only one of those patients had severe TR. In the rest of the 30 patients with biphasic patterns throughout the operation, peak A and D velocities increased (p < 0.01), whereas peak S and V velocities decreased (p < 0.01) after CPB compared with those before CPB. Consequently, peak S/D was reduced (p < 0.01), and %RF/FF increased (p < 0.05). These post-CPB changes were associated with increased (p < 0.01) pulmonary artery diastolic and right atrial pressures. Thus, this study indicates that before CPB, low peak S/D without significant TR could be indicative of reduced right ventricular (RV) systolic function in patients with a history of inferior MI. After CPB, reduced peak S/D and increased %RF/FF may be indicative of a decrease in RV function secondary to the operative procedure and/or poor protection of the right heart. Copyright (C) 1995 by W.B. Saunders Company