Preoperative selection of patients with severely impaired left ventricular function for coronary revascularization. Role of low-dose dobutamine echocardiography and exercise-redistribution-reinjection thallium SPECT.

BACKGROUND

Both thallium imaging and low-dose dobutamine echocardiography have been proposed to predict the reversibility of left ventricular (LV) dysfunction in patients with coronary disease. The present study was designed to evaluate whether the use of these techniques during the preoperative assessment of coronary patients with depressed LV function can improve our ability to identify those likely to have improved LV function after surgery.

METHODS AND RESULTS

Forty consecutive patients (age, 60 +/- 10 years) with coronary disease and an ejection fraction < or = 35% underwent dobutamine echocardiography (10 micrograms/kg per minute) and exercise-redistribution-reinjection thallium single photon emission computed tomography (SPECT) before coronary revascularization by bypass surgery (n = 33) or angioplasty (n = 7). Recovery of LV function was evaluated by echocardiography 5.3 +/- 2.4 months after revascularization. According to the changes in end-systolic volume and ejection fraction after revascularization, the patients were categorized into groups with (n = 19) and without (n = 21) postoperative functional improvement, defined as a > 5% increase in ejection fraction and > 10 mL decrease in end-systolic volume. Before revascularization, patients with improved postoperative function had smaller end-diastolic volume and less wall motion abnormalities than those with persistent dysfunction. They also showed greater improvement of wall motion score with dobutamine (6.1 +/- 2.4 versus 1.8 +/- 4.2 grades, P < .001) and smaller thallium defect score after exercise (38 +/- 12 versus 47 +/- 14 grades, P = .04). Discriminant analysis selected the improvement in wall motion score with dobutamine and baseline end-diastolic volume as independent predictors of postoperative recovery. Consideration of both parameters allowed prediction of functional outcome in 84% of the patients with and 81% of those without postoperative improvement.

CONCLUSIONS

Among the parameters commonly available before surgery in coronary patients with depressed LV function, the maintenance of significant inotropic reserve, the severity of LV remodeling, and the magnitude of the perfusion defect after exercise can predict the reversal of LV dysfunction after revascularization.