The Supplementary Role of Non-invasive Imaging to Routine Clinical Practice in Suspected Non-ST-elevation Myocardial Infarction

The Supplementary Role of Cardiovascular Magnetic Resonance Imaging and Computed Tomography Angiography to Routine Clinical Practice in Suspected Non-ST Elevation Myocardial Infarction - A Randomized Controlled Trial

Approximately half of patients with acute chest pain, a very common reason for emergency department visits worldwide, have a cardiac cause. Two-thirds of patients with a cardiac cause are eventually diagnosed with a so-called non-ST-elevation myocardial infarction. The diagnosis of non-ST-elevation myocardial infarction is based on a combination of symptoms, electrocardiographic changes, and increased serum cardiac specific biomarkers (high-sensitive troponin T). Although being very sensitive of myocardial injury, increased high-sensitive troponin T levels are not specific for myocardial infarction. Invasive coronary angiography is still the reference standard for coronary imaging in suspected non-ST-elevation myocardial infarction. This study investigates whether non-invasive imaging early in the diagnostic process (computed tomography angiography (CTA) or cardiovascular magnetic resonance imaging (CMR)) can prevent unnecessary invasive coronary angiography. For this, patients will be randomly assigned to either one of three strategies: 1) routine clinical care and computed tomography angiography early in the diagnostic process, 2) routine clinical care and cardiovascular magnetic resonance imaging early in the diagnostic process, or 3) routine clinical care without non-invasive imaging early in the diagnostic process.

Inclusion Criteria:

• Prolonged symptoms suspected of cardiac origin (angina pectoris or angina equivalent), and presentation on the cardiac emergency department <24 hours after symptom onset

  • Increased levels of high-sensitive Troponin-T (>14ng/L)
  • Age >18 years and <85 years
  • Willing and capable to give written informed consent
  • Written informed consent

Exclusion Criteria:

• Ongoing severe ischemia requiring immediate invasive coronary angiography

• Shock (mean arterial pressure < 60 mmHg) or severe heart failure (Killip Class ≥ III)

• ST-elevation myocardial infarction (ST-elevation in 2 contiguous leads: ≥0.2mV in men or ≥0.15 mV in women in leads V2-V3 and/or ≥0.1 mV in other leads or new left bundle branch block)

• Chest pain highly suggestive of non-cardiac origin:

  • Acute aortic dissection
  • Acute pulmonary embolism (high risk patient defined as Wells score >6)
  • Musculoskeletal or gastro-intestinal pain
  • Other (pneumothorax, pneumonia, rib fracture, etc.)

• Previously known coronary artery disease, defined as:

  • Any non-invasive diagnostic imaging test positive for coronary artery disease
  • Coronary stenosis >50% on any previous invasive coronary angiography or computed tomography angiography
  • Documented previous myocardial infarction
  • Documented previous coronary artery revascularization
  • Known cardiomyopathy

• Pregnancy

• Life threatening arrhythmia on the cardiac emergency department or prior to presentation

• Tachycardia (≥100/bpm)

• Atrial fibrillation

• Angina pectoris secondary to anemia (<5.6 mmol/L), untreated hyperthyroidism, aortic valve stenosis (aortic valve area ≤ 1.5 cm2), or severe hypertension (>200/110 mmHg)

• Life expectancy <1 year (malignancy, etc.)

• Contraindications to cardiovascular magnetic resonance imaging: metallic implant (vascular clip, neuro-stimulator, cochlear implant), pacemaker or implantable cardiac defibrillator, claustrophobia