CORONARY REVASCULARIZATION IN THE TREATMENT OF MODERATE AND SEVERE POSTISCHEMIC LEFT-VENTRICULAR DYSFUNCTION

Chronic postischemic left ventricular (LV) dysfunction can improve fol lowing coronary revascularization (hibernating myocardium). However, i t is not clear whether the severity of LV dysfunction determines funct ional outcome after revascularization and the accuracy of tests to pre dict myocardial viability. We studied 47 patients with coronary artery disease and chronic LV dysfunction. Before coronary bypass, patients underwent (F-18)2-fluoro-2-deoxy-D-glucose (FDG) positron emission tom ography (PET) during euglycemic hyperinsulinemic clamp to assess viabi lity. Global and regional LV function were assessed before and 4 to 6 months after surgery. Patients were arbitrarily divided into 2 groups with moderate and severe LV dysfunction. Group 1 (n = 26) had an elect ion fraction (EF) of less than or equal to 30% and group 2 (n = 21) >3 0%. After bypass, the EF (22 +/- 6% vs 31 +/- 10%; p < 0.0001) and glo bal wall motion score (WMS) (2.05 +/- 0.39 vs 1.56 +/- 0.34; p <0.001) improved in group 1, whereas the EF (43 +/- 9% vs 43 +/- 12%; p = NS) was unchanged in group 2, although WMS tended to improve (1.42 +/- 0. 38 vs 1.32 +/- 0.39; p = 0.09). The proportion of dysfunctional segmen ts (72% vs 32%; p <0.0001) and FDG uptake in these segments (0.44 +/- 0.15 vs 0.34 +/- 0.15 mu mol/g/min, p <0.0001) were greater in group 1 than in group 2. The baseline EF influenced the predictive accuracy o f PET, with highest positive predictive accuracy in group 2 and highes t negative predictive accuracy in group 1. Thus, coronary revasculariz ation has the potential for greatest benefit in patients with the most severe dysfunction, but with evidence of viability, and the entity of LV dysfunction affects the predictive accuracy of viability studies. (C) 1998 by Excerpta Medico, Inc.