Abstract 692: Low Dose Dobutamine is a Better Predictor than the Transmural Extent of Infarction in Segments with an Intermediate Extent of Infarction; Controlled Trial
Predictive value of MRI in segments with an intermediate transmural extent of infarction (TEI between 1–75%) is moderate. Therefore we investigated if addition of low dose dobutamine improves accuracy in these segments in a controlled study. MRI was performed in 43 patients before and 6 months after successful revascularization for a chronic total occlusion (CTO) and compared to 20 patients with non-successful revascularization. Segmental wall thickening (SWT) at rest and during low dose dobutamine (LDD) and ejection fraction (EF) were quantified on cine images and TEI on delayed enhancement (DE)-MRI. Baseline patient characteristics for both groups were comparable. In patients with successful revascularization EF increased (51 ± 12% to 55 ± 12%; p=0.006) whereas in the control group EF remained unchanged. SWT of all dysfunctional (SWT<45%) CTO perfused segments increased during LDD from 16 ± 19% to 31 ± 34% (p<0.001) which was similar to the improvement by revascularization 16 ± 17% to 32 ± 30% (p<0.001). SWT changed significantly after revascularization in segments with a TEI<75%. In segments with non-successful revascularization no improvement in SWT was observed (figure⇓). The predictive accuracy for DE-MRI in segments with an intermediate extent of infarction was 47% using TEI<25% as a cut of value for viability, 50% using TEI<50% as a cut of vale for viability and 56% using TEI<75% as a cut of for viability. The predictive accuracy for low dose dobutamine in these segments was 70%. Low dose dobutamine in combination with TEI is a better predictor for functional recovery than TEI alone in segments with an intermediate extent of infarction.