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Objective: To investigate the influence of infarct zone viability on remodelling after late recanalisation of an occluded infarct related artery. Methods: A subgroup of 26 volunteers from TOAT (the open artery trial) underwent dobutamine stress cardiovascular magnetic resonance at baseline to assess the amount of viable myocardium present with follow up to assess remodelling at one year. TOAT studied patients with left ventricular dysfunction after anterior myocardial infarction (Ml) associated with isolated proximal occlusion of the left anterior descending coronary artery with randomisation to percutaneous coronary intervention (PCI) with stent at 3.6 weeks after MI (PCI group) or to medical treatment alone (medical group). Results: In the PCI group there was a significant relation between the number of viable segments within the infarct zone and improvement in end systolic volume index (-7.7 ml/m2, p = 0.02) and increased ejection fraction (4.1 %, p = 0.03). The relation between viability and improvements in end diastolic volume index (-8.8 ml/m2, p = 0.08) and mass index (-6.3 g/m2, p = 0.01) did not reach significance (p = 0.27 and p = 0.8, respectively). In the medical group, there was no significant relation between the number of viable segments in the infarct zone and the subsequent changes in end diastolic (p = 0.84) and end systolic volume indices (p = 0.34), election fraction (p = 0. 1), and mass index (p = 0.24). Conclusion: The extent of viable myocardium in the infarct zone is related to improvements in left ventricular remodelling in patients who undergo late recanalisation of an occluded infarct related artery. [ABSTRACT FROM AUTHOR]

This article focuses an open and shut medical case of late opening of the infarct related artery. The open artery hypothesis therefore remains controversial. Of the randomised studies to date, three have shown no significant benefits between invasive versus conservative strategies for the treatment of occluded IRAs late after ML one study strongly supports an invasive strategy, and our data strongly refutes the open artery hypothesis. These results are interesting and in support of the open artery hypothesis.