Clinical outcome of patients with previous myocardial infarction and left ventricular dysfunction assessed with myocardial Tc-99m-MIBI SPECT and F-18-FDG PET

Myocardial viability was assessed by Tc-99m-methoxyisobutylisonitrile (MIBI ) SPELT and F-18-FDG PET to evaluate the prognosis and treatment strategy o f patients with myocardial infarction (MI) and left ventricular (LV) dysfun ction. Methods: One hundred twenty-three consecutive patients with previous MI and LV dysfunction (LV ejection fraction [EF], 35%+/-6% [mean +/- SD]) who underwent Tc-99m-MIBI SPELT and FDG PET were followed-up for 26 +/- 10 mo (mean +/- SD). Distributions of the 2 radiotracers in myocardial segment s were classified into 2 patterns: myocardial perfusion-metabolism mismatch (MM) and match (M). LV EF and LV end-diastolic diameter (EDD) were measure d by echocardiography at baseline, 3 mo (Pos1), and 6 mo (Pos2) after revas cularization. Cardiac death, acute MI, unstable angina, and late revascular ization (>3 mo) experienced by the patients during follow-up were defined a s cardiac events. Results: Sixty-seven patients underwent revascularization and 56 patients were treated medically. Of the 72 patients with greater th an or equal to2 MM segments, 42 underwent revascularization (group A1) and 30 were treated medically (group A2). Of the 51 patients with <2 MM segment s, 25 underwent revascularization (group B1) and 26 were treated medically (group B2). The 4 groups had similar baseline characteristics and rest LV E F. After revascularization, EF (mean SD) increased in group A1 from 36%<plu s/minus>5% to 44%+/-8% (P<0.0001) in Post and to 51%<plus/minus>9% (P<0.000 1) in Post. EDD (mean<plus/minus>SD) decreased from 62 +/-8 mm to 56 +/-5 m m (P<0.001) in Post and to 55<plus/minus>5 mm (P<0.001) in Post. However, E F and EDD were unchanged in group B1 (P>0.05). During the follow-up, 22 pat ients (17.9%) suffered from cardiac events, including 11 cardiac deaths, 4 acute MI, 6 late coronary artery bypass grafting, and 1 unstable angina pec toris. The cardiac event rate in group A2 (50%) was significantly higher th an that of groups A1 (2.4%; chi (2) = 23.08; P<0.0001), B1 (12%; <chi>(2) = 8.94; P = 0.003), and B2 (11.5%; chi (2) = 9.45; P = 0.002). Conclusion: A ssessment of myocardial viability using hybrid Tc-99m-MIBI SPELT and FDG PE T can predict the clinical outcome and is helpful to decision making in the treatment strategy of patients with MI and LV dysfunction. Revascularizati on can improve the LV function and clinical outcome of patients with >2 via ble myocardial segments.