Myocardial perfusion correlates with improvement of systolic function of the left ventricle after CABG. Dobutamine echocardiography and Tc-99m-MIBI SPECT study.

ABSTRACT

OBJECTIVE: The aim of the study was to assess the effect of surgical revascularization [coronary artery bypass grafting (CABG)] on systolic function and perfusion of the left ventricle using dobutamine echocardiography (DE) and Tc-99m-MIBI SPECT (SPECT). METHODS: There were 32 patients mean age 52.2+/-7.2 years in whom DE and SPECT were performed before and 3-4 months after CABG using standard protocols. Wall motion score index (WMSI) and perfusion index (PI) were calculated. RESULTS: Significant improvement of WMSI at rest (1.44+/-0.46 vs 1.33+/-0.41; P=0.03) as well as after maximal dose of dobutamine (1.49+/-0.42 vs 1.39+/-0.44; P=0.02) was observed after CABG as compared to preoperative examination. Similar relation was observed during SPECT study. Perfusion index diminished significantly after revascularization during rest acquisition (2.19+/-0.71 vs 1.93+/-0.70; P=0.0008) and after Dipirydamole administration (2.73+/-0.73 vs 2.20+/-0.69; P=0.0001) as compared to preoperative examination. We found correlation between PI and WMSI at rest before CABG (R=0.46; P=0.01), PI after Dipirydamole and WMSI after maximal dose of Dobutamine before CABG (R=0.37; P=0.04), PI and WMSI at rest after CABG (R=0.39; P=0.03), PI after Dipirydamole and WMSI after dobutamine after CABG (R=0.38; P=0.03). CONCLUSIONS: Surgical revascularization significantly improves both perfusion and contractility. Increased perfusion after CABG correlates with improvement of systolic function of the left ventricle.