Percutaneous coronary intervention in late presentation acute myocardial infarction without viability. effects on left ventricular remodelling and contractility ­ rationale and design

ABSTRACT

INTRODUCTION: The potential benefits attributable to late reperfusion fall under the "open artery hypothesis", in which the stunned peri-infarction zone after revascularization restores blood supply, improving its contractility. A study showed that late coronary recanalization after myocardial infarction (MI), irrespective of the viability status, improved left ventricular ejection fraction (LVEF) and myocardial contractility mainly in the segments adjacent and distant to the infarction. Purpose: To evaluate whether late recanalization in patients with STEMI without viability by Cardiovascular Magnetic Resonance (CMR) can reduce the reverse remodeling. Viable cases will be kept in the registry. METHODS: This is a prospective randomized controlled trial, with at least 6 months follow-up. Patients with STEMI not reperfused between 24 hours and 28 days with IRA with lesion greater than 50% with segmental dysfunction and absence of viability on CMR are eligible for inclusion. Patients with previous MI, cardiomyopathy or clinical instability are excluded. Participants randomly assigned (11) to PCI and Optimal Medical Treatment (OMT) or only OMT. Expected outcome is the change on reverse remodeling of the end systolic volume at 6 months likewise the improvement in segmental contractility at 6 months. The sample size of 35 patients in each group provides 80% power with a two-sided significance level of 0.05. Descriptive statistics and statistical inferential methods are employed to measure changes between the groups. The trial has local ethical review board approval. RESULTS: 28 patients have been already enrolled. CONCLUSION: This trial will provide insights into the potential benefits of opening the IRA in segments without viability, improving contractility of surrounding myocardium.