Abstract 2810: The Occluded Artery Trial (OAT) Viability Ancillary Study (OAT-NUC): Influence of Infarct Zone Viability on Left Ventricular Remodeling After PCI vs. Medical Therapy Alone

Abstract

Introduction: OAT recently reported no difference in long-term outcomes between percutaneous intervention (PCI) vs. medical therapy alone (MED) in stable post-MI patients with occluded infarct-related arteries (IRAs). Whether PCI may benefit a subset of patients with relative preservation of infarct zone (IZ) viability is unknown. Hypotheses: IZ viability influences left ventricular (LV) remodeling and PCI patients with viability have less adverse remodeling than comparable MED post-MI patients with an occluded IRA. Methods: Patients were eligible for OAT-NUC based on the main OAT criteria. Enrolled patients underwent a resting nitroglycerin-enhanced 99m-Tc sestamibi SPECT study at baseline prior to OAT randomization and repeated 1 year after randomization. SPECT studies were quantitatively analyzed in a central core lab, blinded to OAT randomization and to sequence. Parameters included LV volumes (for remodeling over time), LV regional and global function, infarct size, and IZ viability. Results: There were 124 patients enrolled in OAT-NUC at 20 international sites. For patients with complete baseline and 1 year information as of May 2007 (n=78), infarct size was 24 ± 16% of the LV (mean ± SD), EF 48 ± 11%, end-diastolic volume 127 ± 52 ml, end-systolic volume 71 ± 46 ml, and sestamibi uptake within the IZ was 43 ± 8% of peak counts. Those with severe reduction in IZ viability (IZ uptake <40% of peak counts, n=25) compared to those with at least moderate preservation of viability (IZ counts <40% of peak counts, n=53) had larger infarct size (p<0.001), larger end-diastolic (p<0.001) and end-systolic (p<0.003) volumes at baseline. Complete data acquisition and analysis of the primary and secondary end point results examining the influence of IZ viability on extent of LV remodeling, and the interaction of IZ viability with extent of remodeling for PCI vs. MED in post-MI patients with occluded IRAs will be available for the entire patient cohort by August 2007. Conclusions: The OAT-NUC ancillary study examines the influence of IZ viability on LV remodeling in post-MI patients with occluded IRAs randomized to PCI vs. medical treatment alone and will provide mechanistic insights into the clinical findings of the main OAT study.