Synopsis
Diagnose and risk-stratify NSTE-ACS, deliver antithrombotic care safely and match invasive timing to instability, ischaemic risk and bleeding risk.
- NSTEMI is acute myocardial injury with evidence of ischaemia but without persistent diagnostic ST elevation; unstable angina has ischaemia without biomarker evidence of necrosis.
- Give aspirin 300 mg promptly unless contraindicated, then continue low-dose aspirin indefinitely in most patients.
- Do not start dual antiplatelet therapy before unstable angina or NSTEMI is diagnosed.
Key red flags
Refractory or recurrent rest pain, shock, acute heart failure, serious arrhythmia or dynamic widespread ST change requires immediate invasive assessment.
Investigation priorities
Detect dynamic ischaemia and rhythm complications.
Management branches
Suspected unstable angina or NSTEMI without persistent ST elevation
- Perform ABCDE, monitoring, ECG and serial assay-specific troponin; treat pain and hypoxaemia when present.
- Give aspirin 300 mg unless contraindicated; once unstable angina or NSTEMI is diagnosed, give fondaparinux unless bleeding risk is high or immediate angiography is planned.
Stable NSTE-ACS after initial treatment
Key medicines
Aspirin300 mg orally as a single loading dose as soon as possible, then usually 75 mg once daily indefinitely.
Fondaparinux2.5 mg by subcutaneous injection once daily, started after diagnosis and continued for up to 8 days or until earlier discharge.