How should I assess the risk of myocardial infarction in a patient presenting with chest pain?

To assess the risk of myocardial infarction (MI) in a patient presenting with chest pain, a comprehensive approach involving clinical assessment and specific diagnostic tests is required.

• Initial Assessment and Clinical History:
  • Begin by taking a detailed clinical history ¹. This should include the patient's age and sex, the characteristics of the pain (location, radiation, severity, duration, frequency, and factors that provoke or relieve it), and any associated symptoms like breathlessness ¹.
  • It is also important to document any history of angina, MI, coronary revascularisation, or other cardiovascular disease, as well as any cardiovascular risk factors ¹.
  • For acute presentations, this detailed history should be taken unless a ST-segment-elevation myocardial infarction (STEMI) is confirmed from the resting 12-lead ECG ¹.
• Physical Examination:
  • Carry out a physical examination to identify risk factors for cardiovascular disease, signs of other cardiovascular disease, and non-coronary causes of angina (for example, severe aortic stenosis, cardiomyopathy) ¹.
  • The examination should also aim to exclude other causes of chest pain ¹.
  • For acute chest pain, the physical examination should determine haemodynamic status, signs of complications (for example, pulmonary oedema, cardiogenic shock), and signs of non-coronary causes of acute chest pain, such as aortic dissection ¹.
• Diagnostic Tests for Acute Chest Pain:
  • On arrival in hospital, take a resting 12-lead ECG and a blood sample for high-sensitivity troponin I or T measurement ¹.
  • Do not routinely offer non-invasive imaging or exercise ECG in the initial assessment of acute cardiac chest pain ¹.
  • Consider a chest X-ray to help exclude complications of acute coronary syndrome (ACS) such as pulmonary oedema, or other diagnoses like pneumothorax or pneumonia ¹. Early chest computed tomography (CT) should only be considered to rule out other diagnoses such as pulmonary embolism or aortic dissection, not to diagnose ACS ¹.
• Risk Stratification for Future Adverse Cardiovascular Events:
  • Use predicted 6-month mortality to categorise the risk of future adverse cardiovascular events ².
  • Risk categories are defined as: Lowest (1.5% or below), Low (>1.5% to 3.0%), Intermediate (>3.0% to 6.0%), High (>6.0% to 9.0%), and Highest (over 9.0%) ². These categories are derived from the Myocardial Ischaemia National Audit Project (MINAP) database ².
  • Record the results of the risk assessment in the patient's care record ².
  • This risk assessment guides clinical management, balancing the benefit of treatment against any risk of related adverse events ².
  • Be aware that some younger people with low risk scores for mortality at 6 months may still be at high risk of adverse cardiovascular events and may benefit from early angiography ².