Managing unstable angina and non-ST elevation MI

Acute coronary syndrome (ACS), encompassing unstable angina (UA), non-ST elevation myocardial infarction (NSTEMI) and ST elevation myocardial infarction (STEMI), is often the result of an acute thrombotic occlusion of the coronary vessels, associated with atheromatous plaque rupture or erosion. ACS is associated with a severely impaired prognosis and requires prompt and efficient specialist treatment. The clinical presentation may be identical across all three components of ACS. Establishing an accurate diagnosis without delay is of paramount importance to start treatment promptly. Patients with suspected ACS need to be referred immediately to A&E. Prehospital treatment, which includes aspirin, nitrates, morphine and oxygen (if hypoxic), should be initiated rapidly. Important features pointing towards a diagnosis of ACS include: typical characteristics of chest pain, presence of risk factors, and ECG changes suggestive of myocardial ischaemia. Chest discomfort in patients with ACS typically occurs at rest, is anginal in character and can range from mild tightness to central crushing chest pain. It may be associated with nausea, dyspnoea or diaphoresis. The chest pain may radiate to the arms, back or jaw and is often >20 minutes in duration. An accurate clinical history and a detailed examination are vital. Initial investigations are the same for all ACS events, with the need for urgent serial ECGs and the measurement of cardiac troponin levels, to assess myocardial damage. In NSTEMI, ECG changes suggestive of ischaemia are often present and associated with elevated cardiac troponin. In UA, there is a considerable reduction in myocardial perfusion leading to symptoms; but there is no rise in cardiac troponin. Risk stratification is imperative in assessment of ACS to allow efficient delivery of specialist care. Treatment includes: antiplatelets; antithrombotic agents; angina drugs; analgesia, and PCI.