Ischaemic heart disease: management of non-ST elevation acute coronary syndrome

Diagnosis of non-ST segment elevation acute coronary syndrome (NSTE-ACS) is based on clinical assessment, electrocardiogram and serum biomarker concentration. Diagnosis of myocardial infarction requires the detection of a rise of cardiac biomarker concentration with at least one value above the upper reference limit, and at least one feature of myocardial ischaemia such as typical symptoms or electrocardiographic abnormality. High-sensitivity assays allow detection of serum troponin earlier after symptom onset but decrease specificity, with raised serum troponin detected in conditions other than NSTE-ACS. Patients with NSTE-ACS are at increased risk of adverse cardiovascular outcomes, and should be risk-stratified using established risk scoring systems (e.g. GRACE-2.0) to identify those likely to benefit from evidence-based treatments. Patients with NSTE-ACS should be offered aspirin and an anticoagulant unless contraindicated by bleeding risk. A P2Y12 receptor antagonist should be offered to all patients unless at very low risk (e.g. predicted 6-month mortality <1.5%). Glycoprotein IIb/IIIa receptor inhibitors reduce the risk of ischaemic events but increase bleeding, and are rarely used outside catheter laboratories. A routine invasive strategy (coronary angiography and revascularization if suitable coronary anatomy) improves outcome and is recommended for all patients at high risk (e.g. predicted 6-month mortality >3%) and no contraindications (e.g. active bleeding, co-morbidity).