Usefulness of the ejection fraction response to Dobutamine infusion in predicting functional recovery after coronary artery bypass grafting in patients with left ventricular dysfunction

Quantification of dysfunctional but viable myocardium has high prognostic v alue for improvement of left ventricular (LV) function after coronary arter y bypass grafting (CABG). Dobutamine stress echocardiography (DSE) can asse ss viable myocardium by segmental wall motion changes during stress. Howeve r, analysis of wall motion is subjective with only moderate interinstitutio nal agreement (70%) and frequently overestimates functional improvement aft er CABG. In contrast, calculation of election fraction (EF) is less subject ive and allows a more precise quantification of global contractile reserve. The aim of the study was to compare the prognostic value of EF response an d segmental wall motion changes during DSE for the prediction of LV functio nal recovery after CABG. Forty patients underwent DSE before CABG. EF respo nses were assessed at rest, low-dose dobutamine, and at peak stress using t he biplane disk method. Wall motion was scored using a 16-segment 5-point m odel. Resting radionuclide ventriculography (RNV-LVEF), performed before an d 8 +/- 2 months after CABG, was used as an independent reference. Five pat ients were excluded because of perioperative infarction or poor echo images . In 11 of 35 patients, RNV-LVEF recovered >5%. Improvement in EF during do butamine infusion predicted RNV-LVEF recovery after CABG significantly bett er than segmental wall motion changes (72% vs 53%, p = 0.03). A biphasic EF response (i.e., improvement in greater than or equal to 10% at low dose an d subsequent worsening at peak stress) had the highest predictive value (80 %) for late functional recovery. In conclusion, EF response to dobutamine i nfusion was superior to segmental wall motion changes in predicting RNV-LVE F recovery after CABG. (C) 2000 by Excerpta Medica, Inc.