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Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.

Non-ST-elevation myocardial infarction and unstable angina

Cardiology · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

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Escalate

Offer immediate coronary angiography for NSTE-ACS with clinical instability, including haemodynamic compromise, recurrent or refractory pain, life-threatening arrhythmia or acute heart failure; do not wait for a GRACE score to override instability.

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.
  • Offer fondaparinux for unstable angina or NSTEMI when bleeding risk is not high, unless immediate angiography is planned.
  • Use serial high-sensitivity troponin and repeat ECG; one normal tracing or early troponin does not close the diagnosis.
  • Immediate angiography follows instability, not a numerical risk score.
  • When stable, use a validated risk tool; NICE offers angiography within 72 hours when predicted 6-month mortality is above 3% and there is no contraindication.
  • Do not give prasugrel before coronary anatomy is defined in NSTE-ACS; if selected, load it at PCI.
  • Balance DAPT potency and duration against bleeding, oral-anticoagulant indication, frailty, renal function and planned surgery.

Key red flags

Unstable NSTE-ACS

Refractory or recurrent rest pain, shock, acute heart failure, serious arrhythmia or dynamic widespread ST change requires immediate invasive assessment.

Dynamic ischaemic ECG

New ST depression or transient ST elevation during pain materially raises risk even if the initial troponin is low.

Bleeding hazard

Active bleeding, recent intracranial haemorrhage, severe thrombocytopenia or urgent surgical need changes antithrombotic strategy and requires senior input.

Investigation priorities

01
Serial 12-lead ECGFirst step

Detect dynamic ischaemia and rhythm complications.

Management branches

Preferred routeInitial NSTE-ACS care

Suspected unstable angina or NSTEMI without persistent ST elevation

  1. Perform ABCDE, monitoring, ECG and serial assay-specific troponin; treat pain and hypoxaemia when present.
  2. 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.
  3. Assess instability, ischaemic risk, bleeding risk, comorbidity and any ongoing oral-anticoagulant indication.
  4. Escalate any recurrent pain, dynamic ECG change, arrhythmia, heart failure or haemodynamic deterioration.
Preferred stable routeRisk-guided angiography

Stable NSTE-ACS after initial treatment

  1. Calculate predicted 6-month mortality using an established risk tool and apply clinical judgement.
  2. Offer angiography within 72 hours when risk is above 3% and there is no contraindication.
  3. Use radial access when suitable and physiology for intermediate lesions; proceed to PCI or Heart Team discussion as anatomy indicates.

Key medicines

Aspirin300 mg orally as a single loading dose as soon as possible, then usually 75 mg once daily indefinitely.Active major bleeding or true hypersensitivity; assess gastroprotection and combined antithrombotic bleeding risk.
Fondaparinux2.5 mg by subcutaneous injection once daily, started after diagnosis and continued for up to 8 days or until earlier discharge.Contraindicated with active clinically significant bleeding, acute bacterial endocarditis or creatinine clearance below 20 ml/min. If serum creatinine is above 265 micromol/l, NICE advises considering UFH adjusted to clotting monitoring. At PCI after fondaparinux, add IV UFH: 70–100 units/kg without a glycoprotein IIb/IIIa inhibitor or 50–70 units/kg with one, adjusted to activated clotting time and bleeding risk.
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Sources and review status8 sources · checked 27 Aug 2026 · clinical review pending+
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.

  • NICE NG185: Acute coronary syndromes
  • NICE QS68: Angiography within 72 hours for NSTEMI or unstable angina
  • ESC 2023 Guidelines for acute coronary syndromes
  • Arixtra 2.5 mg SmPC
  • Brilique 90 mg SmPC
  • Plavix 300 mg SmPC
  • Prasugrel 10 mg tablets SmPC
  • NICE NG238: Cardiovascular disease risk assessment and lipid modification

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateRapid draftClinical stateAwaiting reviewJurisdictionUnited Kingdom
If invasive treatment is not appropriate, document why and optimise medical therapy and follow-up.