OCT Versus Angiography for Culprit Lesion Revascularization in Acute Myocardial Infarction PatiEnts

Percutaneous coronary intervention (PCI) is a standard treatment for significantly stenotic lesion of coronary arteries, especially in the setting of acute myocardial infarction (AMI) where timely reperfusion is important. Traditionally, visual assessment by coronary angiography has been the main tool to identify coronary artery disease and guide revascularization. However, it is known that angiography alone is unable to adequately evaluate significance of stenotic lesion or optimization status of the stent, and that angiography suffers from high intra- and interobserver variability. Thus, methods for intracoronary imaging and/or physiology have been developed to aid these limitations.

During the PCI procedure, intravascular imaging devices such as intravascular ultrasound (IVUS) and optical coherence tomography (OCT) are useful tools for providing information on lesion characteristics and optimal stent implantation with regard to appropriate reference segment, stent expansion, stent apposition, and possible acute complications. Therefore, intravascular imaging guidance may improve clinical outcomes after complex PCI. However, although previous randomized controlled trial and registries showed significantly lower rates of major adverse clinical events following IVUS-guided PCI compared with angiography-guided PCI, the randomized controlled trials were limited with small sample size and dealt with very selected lesion subsets such as chronic total occlusion (CTO) or long lesions. Moreover, although some studies observed similar clinical outcomes between IVUS-guided PCI and OCT-guided PCI, it is uncertain whether OCT-guided PCI improves clinical outcomes compared with angiography-guided PCI.

Currently, randomized controlled trial to support beneficial impact of OCT-guided PCI, especially in patients with acute myocardial infarction (AMI) is lacking. One randomized clinical trial in 2016 with 240 non-ST-elevation myocardial infarction patients have reported higher postprocedural fractional flow reserve and similar incidence of major adverse cardiac events with the use of OCT compared to angiography alone, but this study mostly focused on immediate physiologic findings of OCT-guided PCI and only demonstrated clinical outcomes on short-term follow-up. Although the ILUMIEN IV trial evaluated efficacy of OCT-guided PCI among high risk patients including lesions were considered to be responsible for a recent myocardial infarction, there was no apparent difference in the target-vessel failure at 2 years. There is no randomized controlled trial that can provide information on its long-term clinical impact, and current clinical guidelines puts OCT on Class 2a recommendation as an alternative for IVUS, with the exception of ostial left main disease.

In this regard, randomized controlled trial comparing clinical outcome following PCI in patients with AMI where procedural optimization is performed under OCT-guidance or angiography alone would provide valuable evidence to enhance prognosis after treatment of AMI. Therefore, FRAME-AMI 3 trial has been designed to compare clinical outcomes after PCI for infarct-related artery using either OCT-guided or angiography-guided strategy.