General principles of management of confirmed acute coronary syndrome

Acute coronary syndromes are commonly related to atherothrombotic stenosis and/or occlusion of the epicardial coronary arteries.

Patients with acute coronary syndrome usually present with acute chest discomfort or chest pain–equivalent symptoms such as shortness of breath, epigastric pain and left arm pain, though presenting symptoms can vary widely (for more details, see Acute chest pain of possible cardiac origin).

Based on the electrocardiogram (ECG), patients are divided into either ST elevation myocardial infarction (STEMI) or non–ST elevation acute coronary syndromes (NSTEACS) (no persistent ST elevation on ECG). Based on cardiac troponin values, NSTEACS is further divided into non–ST elevation myocardial infarction (NSTEMI) (which presents with elevated troponin) and unstable angina. This is shown in Classification of coronary ischaemic syndromes. NSTEMI and unstable angina can progress to a STEMI, so ongoing monitoring is essential.

The priority for managing STEMI is re-establishing blood flow in the occluded coronary artery (reperfusion), which is achieved with percutaneous coronary intervention (PCI), or thrombolytic therapy if PCI is unavailable. See ST elevation myocardial infarction for information on management.

The priority for managing NSTEMI is plaque stabilisation, and the prevention of coronary occlusion with medical therapy (including antiplatelet and anticoagulant therapy) and revascularisation (ie stenting or bypass surgery). Thrombolytic therapy is not used to treat NSTEMI. See Non–ST elevation acute coronary syndromes for information on management.

Unstable angina is defined as myocardial ischaemia at rest or on minimal exertion in the absence of acute cardiomyocyte injury or necrosis (ie normal troponin values). Unstable angina has become a less common diagnosis because of the introduction of high-sensitivity troponin assays that can detect minimal amounts of myocardial necrosis. The management of unstable angina depends on risk stratification; see Overview of management of non-ST elevation acute coronary syndrome (NSTEACS) for information on risk features. For patients with no risk features, see Low risk unstable angina for information on management. Unstable angina can progress to NSTEMI or STEMI, so ongoing monitoring is essential.

Recurrent pain during an acute coronary syndrome may indicate reinfarction requiring urgent intervention. See Recurrent pain in acute coronary syndromes for information on management.

Long-term management is usually the same for STEMI and NSTEACS; see Long-term management of acute coronary syndromes.

Possible complications following myocardial infarction include left ventricular failure, cardiogenic shock, mural thrombus, right ventricular infarction, pericarditis and arrhythmias. See Management of complications following myocardial infarction for more information.

Studies have shown that females with acute coronary syndrome experience delays to reperfusion, lower rates of invasive angiography and appropriate medical therapy, and poorer outcomes compared with malesHay, 2020Khan, 2018Stehli, 2021Stehli, 2019. It is important to be aware that females may present with jaw, back or epigastric pain, and have a high incidence of associated symptoms (eg dizziness, nausea, vomiting, fatigue, palpitations) that may distract from the correct diagnosis of acute coronary syndrome. Females may also have higher incidence of nonatherosclerotic coronary syndromes, such as spontaneous coronary artery dissection, myocardial infarction with nonobstructive coronary arteries and Takotsubo cardiomyopathy. However, these conditions nearly always require coronary angiography for definitive diagnosis and should not delay emergency coronary angiography, particularly in female patients with ST elevation or ongoing ischaemia.