The Occluded Artery Trial (OAT) Viability Ancillary Study (OAT-NUC): influence of infarct zone viability on left ventricular remodeling after percutaneous coronary intervention versus optimal medical therapy alone

Abstract

Background: The Occluded Artery Trial (OAT) showed no difference in outcomes between percutaneous coronary intervention (PCI) versus optimal medical therapy (MED) in patients with persistent total occlusion of the infarct-related artery 3 to 28 days post-myocardial infarction. Whether PCI may benefit a subset of patients with preservation of infarct zone (IZ) viability is unknown.

Methods and results: The OAT nuclear ancillary study hypothesized that (1) IZ viability influences left ventricular (LV) remodeling and that (2) PCI as compared with MED attenuates adverse remodeling in post-myocardial infarction patients with preserved viability. Enrolled were 124 OAT patients who underwent resting nitroglycerin-enhanced technetium-99m sestamibi single-photon emission computed tomography (SPECT) before OAT randomization, with repeat imaging at 1 year. All images were quantitatively analyzed for infarct size, IZ viability, LV volumes, and function in a core laboratory. At baseline, mean infarct size was 26% ± 18 of the LV, mean IZ viability was 43% ± 8 of peak uptake, and most patients (70%) had at least moderately retained IZ viability. There were no significant differences in 1-year end-diastolic or end-systolic volume change between those with severely reduced versus moderately retained IZ viability, or when compared by treatment assignment PCI versus MED. In multivariable models, increasing baseline viability independently predicted improvement in ejection fraction (P = .005). There was no interaction between IZ viability and treatment assignment for any measure of LV remodeling.

Conclusions: In the contemporary era of MED, PCI of the infarct-related artery compared with MED alone does not impact LV remodeling irrespective of IZ viability.

Conflict of interest statement

DISCLOSURES

The authors have no conflicts of interest to disclose related to this work. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Heart, Lung, and Blood Institute or the NIH. We request the journal to acknowledge that the Author retains the right to provide a copy of the final manuscript to the NIH upon acceptance for Journal publication, for public archiving in PubMed Central as soon as possible but no later than 12 months after publication by Journal.

Copyright © 2011 Mosby, Inc. All rights reserved.

Figures

Figure 1

Examples of horizontal long-axis view of resting SPECT images from two patients in the OAT-NUC trial illustrating the viability classification. LEFT- A lateral wall infarct, but with some preservation of uptake in the lateral wall (yellow dotted line and arrow), classified as moderately-retained infarct zone viability. RIGHT - A lateral wall infarct, but a very severe reduction in uptake in the lateral wall (white dotted line and arrow) consistent with severely reduced infarct zone viability.

Figure 2

OAT-NUC Study Enrollment and Patient Flow

Figure 3

One year changes in end-diastolic (ED) and end-systolic (ES) volumes and ejection fraction, in patients with severe reduction in viability in the infarct zone (“

Figure 4

One year changes in end-diastolic (ED) and end-systolic (ES) volumes and ejection fraction, in patients who were randomized to the OAT PCI strategy compared to those randomized to optimal medical therapy (MED). There were no significant between-group changes in any of the parameters.