PERIOPERATIVE TRANSESOPHAGEAL ECHOCARDIOGRAPHY WITH LOW-DOSE DOBUTAMINE STRESS FOR EVALUATION OF MYOCARDIAL VIABILITY - A FEASIBLE APPROACH

Background: The feasibility of low-dose dobutamine stress combined wit h transoesophageal echocardiography (TEE) to detect variable left vent ricular myocardium was evaluated in 22 anaesthetised patients prior to sternotomy for elective coronary artery bypass grafting (CABG). Metho ds: After baseline measurements, a dobutamine infusion beginning with 5 mu g.kg(-1) min(-1) was started and eventually increased to 10 mu g. kg(-1) min(-1). Viability was assessed as visual improvement of left v entricular wall motion (LVWM). The criteria for discontinuation of the infusion were: 1. any changes in LVWM, 2. an increase in preanaesthet ic blood pressure exceeding 40 mmHg, and/or a > 20% increase in preana esthetic heart rate compared to preanaesthetic levels. An off-line eva luation of LVWM was based upon visualisation of the left ventricle in a transgastric short-axis mid-papillary (mid-P) view, and the left ven tricle was divided into anterior, septal, inferior, and lateral segmen ts. Moreover, an off-line semiautomatic analysing system was used for assessing regional and global LVWM. With this analysis the effects on LVWM from changes in preload and afterload could be addressed. Results : 19 patients showed a decreased LVWM in one or several segments at ba seline. A total of 36 segments exhibited decreased LVWM (an average of 1.9 segments/patient). Of these, 22 segments (61%) improved with dobu tamine, while 12 segments (33%) did not, and 2 (6%) became more dysfun ctional. Another 6 segments with normal motion at baseline became dysf unctional with dobutamine. According to the off-line semiautomatic ana lysing system for LVWM, there were no statistically significant change s with dobutamine stimulation. Only one patient showed an increased po stoperative aspartateamino-transferase (ASAT) value (3.0 mmol.1(-1)) b ut no ECG changes. Conclusion: Since we regard the visual assessment o f LVWM as being mure applicable for this protocol than the semiautomat ic analysis, we conclude that low-dose dobutamine stress echocardiogra phy seems to be a feasible method for detecting viable myocardium in t he anaesthetised patient scheduled for elective CABG surgery. However, the semiautomatic analysis complemented our findings, since the varia tions in pre-and afterload did not significantly change the size of th e left ventricle, which hereby would imply LVWM changes. (C) Acta Anae sthesiologica Scandinavica 42 (1998).