Perioperative transoesophageal echocardiography with low-dose dobutamine stress for evaluation of myocardial viability: a feasible approach?
BACKGROUND
The feasibility of low-dose dobutamine stress combined with transoesophageal echocardiography (TEE) to detect viable left ventricular myocardium was evaluated in 22 anaesthetised patients prior to sternotomy for elective coronary artery bypass grafting (CABG).


METHODS
After baseline measurements, a dobutamine infusion beginning with 5 micrograms.kg-1.min-1 was started and eventually increased to 10 micrograms.kg-1.min-1. Viability was assessed as visual improvement of left ventricular wall motion (LVWM). The criteria for discontinuation of the infusion were: 1. any changes in LVWM, 2. an increase in preanaesthetic blood pressure exceeding 40 mmHg, and/or a > 20% increase in preanaesthetic heart rate compared to preanaesthetic levels. An off-line evaluation of LVWM was based upon visualisation of the left ventricle in a transgastric short-axis mid-papillary (mid-P) view, and the left ventricle was divided into anterior, septal, inferior, and lateral segments. 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 baseline. A total of 36 segments exhibited decreased LVWM (an average of 1.9 segments/patient). Of these, 22 segments (61%) improved with dobutamine, while 12 segments (33%) did not, and 2 (6%) became more dysfunctional. Another 6 segments with normal motion at baseline became dysfunctional with dobutamine. According to the off-line semiautomatic analysing system for LVWM, there were no statistically significant changes with dobutamine stimulation. Only one patient showed an increased postoperative aspartateaminotransferase (ASAT) value (3.0 mmol.l-1) but no ECG changes.


CONCLUSIONS
Since we regard the visual assessment of LVWM as being more applicable for this protocol than the semiautomatic analysis, we conclude that low-dose dobutamine stress echocardiography seems to be a feasible method for detecting viable myocardium in the anaesthetised patient scheduled for elective CABG surgery. However, the semiautomatic analysis complemented our findings, since the variations in pre- and afterload did not significantly change the size of the left ventricle, which hereby would imply LVWM changes.
Palmgren
I
I
Division of Cardiothoracic Anaesthesia, Thoracic Centre, University Hospital, Uppsala, Sweden.
Hultman
J
J
Houltz
E
E
D000368:Aged; D001026:Coronary Artery Bypass; D004280:Dobutamine; D017548:Echocardiography, Transesophageal; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D016277:Ventricular Function, Left
D004280:Dobutamine