Abstract: Objective Dobutamine ^99mTc-MIBI SPECT has been shown to enhance the detection of myocardial viability,this study evaluated its prognostic value in patients with coronary heart disease and left ventricular(LV) dysfunction after CABG.Methods Before CABG,38 patients(31 male,7 female;mean age was(66.5±7.0) years with LV dysfunction(42.7±12.5)% underwent the rest-dobutamine stressed ^99mTc-MIBI SPECT.The rest ^99mTc-MIBI SPECT follow up was performed 3 months later.Results(1) A post-revascularization improvement in ejection fraction(EF) ≥5% was defined as significant,patients were divided into tow groups:group A:LVEF increased significantly ≥5% in 19 patients at follow-up and group B:LVEF increased<5% in 19 patients.After CABG,LVEF in group A increased(P<0.001);end-diastolic volumes(EDV) and end-systolic volumes(ESV) decreased significantly(P<0.05);but LVEF,EDV and ESV had no change in group B.Three patients in group B had recurrent heart failure at follow-up.(2) According to receive-curve analysis,an increase in ejection fraction≥4.5% after dobutamine administration was the optimal cutoff value for predicting a significant postrevascularization improvement,with 76.9% sensitivity,64% specificity,and 68.4%accuracy.(3) A significant correlation was found between dobutamine and postrevascularization ejection fraction(r=0.83,P<0.001).The increase in ejection fraction during dobutamine administration is a good predictor of an improvement in ejection fraction after revascularization.Conclusion An increase in ejection fraction ≥4.5% during dobutamine ^99mTc-MIBI SPECT was the optimal cutoff value for predicting a significant postrevascularization improvement.

Key words: dobutamine, ^99mTc-MIBI SPECT, CABG, LV dysfunction