Acute myocardial infarction owes to a plaque rupture resulting in total (STEMI) or partial occlusion (NSTEMI) of the coronary artery. In patients with a partial occlusion and multi vessel disease (MVD), identification of the lesion responsible for the current event (culprit) at the time of the examination (coronary angiogram, CAG) can be difficult.

Meanwhile, identification of the culprit lesion is vital to conduct proper treatment. Furthermore, treating an artery with no plaque rupture (non-culprit), imposes a small risk for complications, which may be fatal. Precise identification of the culprit lesion in NSTEMI patients with MVD remains unsettled

The purpose of this study is proper and precise identification of the culprit lesion in NSTEMI patients with MVD.

Background

Acute myocardial infarction owes to a plaque rupture resulting in total (STEMI) or partial occlusion (NSTEMI) of the coronary artery. Current guidelines in NSTEMI recommend an invasive coronary angiogram (CAG) and possible treatment with percutaneous intervention (PCI) within 2-72 hours. In NSTEMI patients and multi vessel disease (MVD), identification of the lesion responsible for the current event (culprit) at the time of the examination can be difficult.

Meanwhile, identification of the culprit lesion is vital to conduct proper treatment in order to restore blood flow to the myocardium. Furthermore, treating an artery with no plaque rupture (non-culprit), imposes a small risk for complications, which may be fatal. In addition, since the symptoms relate to the culprit lesion it is currently unclear whether all stenosis or only the culprit should be treated by PCI. Today precise identification of the culprit lesion in NSTEMI patients with MVD remains unsettled.

Purpose

The overall objective of this study is proper and precise identification of the culprit lesion in NSTEMI patients with MVD.

Methods

The study employs cardiac magnetic resonance (CMR), which allows detection of myocardium exposed to even brief periods of ischemia. Furthermore, Optical Coherence Tomography (OCT) which visualises the coronary artery lumen and wall. OCT allows for direct visualization of atherosclerotic plaques, presence of thrombus and atherosclerotic plaque ruptured that cannot be seen on a CAG alone.

Patients will have CMR performed prior to CAG. The PCI operator determines culprit based on CAG and ECG changes alone. OCT is subsequently performed on culprit lesion(s) and stenosis ≥ 50%.

Sample size calculation

Assuming the culprit lesion can be correctly identified with history/angiography/ECG in 95% of cases a positive predictive value >90% with 95% accuracy can be reached with 100 patients.

Inclusion Criteria:

• Patients > 18 years of age
• NSTEMI (ECG changes and/or troponin/creatine kinase myocardial band (CK-MB) rise) within 48 hours after symptom debut.
• Multivessel disease at CAG: More than one vessel with >50% stenosis.

Exclusion Criteria:

• Known intolerance of heparin or contrast medium.
• Inability to understand information or to provide informed consent.
• estimated glomerular filtration rate (eGFR) < 30 ml/min.
• Other reasons for troponin rise not applicable to acute myocardial infarction.
• Atrial fibrillation at admission.
• Patients with contraindication for CMR will only have OCT performed.
• Potential pregnancy
• Unstable patients requiring acute CAG and PCI

Eligible NSTEMI patients scheduled for CAG at one center