PREDICTION OF IMPROVEMENT OF VENTRICULAR-FUNCTION AFTER REVASCULARIZATION - F-18 FLUORODEOXYGLUCOSE SINGLE-PHOTON EMISSION COMPUTED-TOMOGRAPHY VS LOW-DOSE DOBUTAMINE ECHOCARDIOGRAPHY

Aims To compare assessment of myocardial flow and glucose metabolism b y single-photon emission computed tomogaphy (SPECT) with low-dose dobu tamine echocardiography in predicting improvement in regional and glob al left ventricular function after coronary artery bypass grafting. Me thods and results Thirty patients with regional wall motion abnormalit ies (mean ejection fraction 32 +/- 19%) were studied with low-dose dob utamine echocardiography (5 and 10 mu g.kg(-1).min(-1)) and thallium-2 01/F-18-fluorodeoxygiucose(FDG) SPECT prior to surgery. For comparativ e analysis, a 13-segment model was used. Postoperative improvement was predicted if the echocardiogram showed that wall motion abnormalities were reversible during the dobutamine infusion and there was normal p erfusion or relatively increased FDG uptake in perfusion defects (mism atch) in dyssynergic segments on SPECT. After surgery, ventricular fun ction was reassessed. An echocardiogram was taken at the 3 month follo w-up with the patient at rest. Regional wall motion had improved in 62 /168 (37%) revascularized segments. In predicting functional outcome, low-dose dobutamine echocardiography reached a sensitivity of 89% and a specificity of 82%, with a positive predictive value of 74% and a ne gative predictive value of 93%, whereas for thallium-201/FDG SPECT the se values were 84%, 86%, 78% and 90%, respectively. In patients with m ore than two viable segments on either technique, the wall motion scor e index, a surrogate of global ventricular function, improved signific antly. Conclusion For the optimal prediction of functional outcome, co mbined assessment of flow and FDG imaging is needed. Both thallium-201 /IFDG SPECT and low-dose dobutamine echocardiography appear comparable and similarly accurate in predicting improvement of left ventricular function after surgical revascularization.