Identification of anatomic risk factors for acute coronary events by optical coherence tomography in patients with myocardial infarction and residual nonflow limiting lesions: rationale and design of the PECTUS-obs study

Abstract

Introduction: In patients with myocardial infarction, the decision to treat a nonculprit lesion is generally based on its physiological significance. However, deferral of revascularisation based on nonischaemic fractional flow reserve (FFR) values in these patients results in less favourable outcomes compared with patients with stable coronary artery disease, potentially caused by vulnerable nonculprit lesions. Intravascular optical coherence tomography (OCT) imaging allows for in vivo morphological assessment of plaque 'vulnerability' and might aid in the detection of FFR-negative lesions at high risk for recurrent events.

Methods and analysis: The PECTUS-obs study is an international multicentre prospective observational study that aims to relate OCT-derived vulnerable plaque characteristics of nonflow limiting, nonculprit lesions to clinical outcome in patients with myocardial infarction. A total of 438 patients presenting with myocardial infarction (ST-elevation myocardial infarction and non-ST-elevation myocardial infarction) will undergo OCT-imaging of any FFR-negative nonculprit lesion for detection of plaque vulnerability. The primary study endpoint is a composite of major adverse cardiovascular events (all-cause mortality, nonfatal myocardial infarction or unplanned revascularisation) at 2-year follow-up. Secondary endpoints will be the same composite at 1-year and 5-year follow-up, target vessel failure, target vessel revascularisation, target lesion failure and target lesion revascularisation.

Ethics and dissemination: This study has been approved by the Medical Ethics Committee of the region Arnhem-Nijmegen. The results of this study will be disseminated in a main paper and additional papers with subgroup analyses.

Trial registration number: NCT03857971.

Keywords: coronary heart disease; coronary intervention; myocardial infarction.

Figure 1

PECTUS-obs flowchart. CAG, coronary angiography, FFR, fractional flow reserve, NSTEMI, non-ST-elevation myocardial infarction, OCT, optical coherence tomography, STEMI, ST-elevation myocardial infarction

Figure 2

Lesion assessment in the PECTUS-obs study. Upper left: CAG shows a non-culprit lesion (red box) in the proximal RCA. The radiopaque marker inside the vessel at the location of the lesion represents the OCT lens. Lower left: FFR measurement of the lesion reveals that it is nonflow-limiting (FFR=0.94). Right: OCT imaging shows an atherosclerotic plaque with a lipid arc of 200° and a minimal fibrous cap thickness of 4 µm. This lesion therefore meets the criteria for a vulnerable plaque. CAG, coronary angiography; FFR, fractional flow reserve; OCT, optical coherence tomography; RCA, right coronary artery.