Introduction
The management of Transient Ischaemic Attack (TIA) is a time-critical medical emergency where rapid assessment and intervention significantly reduce the risk of a subsequent, potentially disabling, stroke. In the UK, clinicians primarily rely on two key sets of guidance: the National Institute for Health and Care Excellence (NICE) guideline (Stroke and transient ischaemic attack in over 16s: diagnosis and initial management, CG248) and the Royal College of Physicians (RCP) guideline, delivered through its Sentinel Stroke National Audit Programme (SSNAP) and associated pathways. While aligned on core principles, there are nuanced differences in their recommendations that can influence local service configuration and clinical practice. This comparison focuses on the 2025 landscape, drawing on the latest available versions of these guidelines.
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Diagnosis and Initial Assessment
The urgency of diagnosis is a central theme in both guidelines, but they approach risk stratification and service models with distinct terminology and pathways.
NICE Guideline (CG248)
- Risk Stratification: NICE recommends the use of the ABCD² score as the primary tool for triage. Patients with an ABCD² score of 4 or above should be assessed by a specialist within 24 hours of symptom onset.
- Service Model: The guideline supports assessment in a specialist TIA clinic. It emphasises that diagnosis should be made by a specialist physician experienced in stroke medicine.
- Imaging: NICE advises that patients with a suspected TIA should be offered a brain scan (CT or MRI) within 24 hours. MRI is preferred if available, to identify acute ischaemia and other pathologies.
RCP (SSNAP) Guidance
- Risk Stratification: The RCP pathway has largely moved away from the ABCD² score in isolation. It advocates for a more comprehensive assessment, often categorising patients based on the likelihood of TIA and the perceived risk of early recurrence, frequently driven by specialist clinical judgement and specific clinical features (e.g., atrial fibrillation, crescendo symptoms, focal symptoms >1 hour).
- Service Model: The RCP strongly endorses the model of Hyperacute Stroke Services and integrated stroke units. The expectation is that high-risk TIA patients are managed with the same urgency as acute stroke, often within a 24-hour specialist assessment framework, but with a de facto emphasis on same-day assessment for high-risk cases.
- Imaging: RCP guidance is more assertive regarding advanced imaging. It promotes the use of diffusion-weighted MRI (DWI) as the gold standard to confirm the diagnosis, with a strong push for access to MRI for all suspected TIA patients to guide management decisions confidently.
Key Difference: The most significant divergence is in risk stratification. NICE formally recommends the ABCD² score, providing a clear numerical threshold. The RCP guidance reflects evolving clinical practice that views ABCD² as insufficient, relying instead on a broader clinical assessment to define urgency, which may lead to faster intervention for patients with certain high-risk features, even with a lower ABCD² score.
Secondary Prevention and Treatment
Both guidelines are closely aligned on the fundamental principles of secondary prevention, but subtle differences exist in timing and agent selection.
Antiplatelet Therapy
- NICE: Recommends clopidogrel 300mg stat then 75mg daily as first-line treatment. For patients who cannot tolerate clopidogrel, combination therapy with aspirin 75mg daily and dipyridamole MR 200mg twice daily is recommended.
- RCP: Also recommends clopidogrel first-line. The RCP pathway often incorporates the findings of recent trials more rapidly into local protocols, which may influence the use of short-term dual antiplatelet therapy (DAPT - aspirin and clopidogrel) in specific high-risk non-cardioembolic TIA patients, though this is not a formal divergence from NICE.
Anticoagulation for Atrial Fibrillation
- Both Guidelines: Are in full agreement. For patients with TIA and atrial fibrillation (AF), oral anticoagulation is mandatory. A Direct Oral Anticoagulant (DOAC) such as apixaban or rivaroxaban is preferred over warfarin, unless there are specific contraindications.
- Timing: Both advise starting anticoagulation promptly, typically after a brain scan has excluded haemorrhage. The exact timing (e.g., immediately vs. after 1-2 weeks) should be based on individual bleeding risk and infarct size, with a trend towards earlier initiation with DOACs.
Blood Pressure and Lipid Management
- NICE & RCP: Both recommend initiating statin therapy (e.g., atorvastatin 20-80mg) immediately after the TIA, regardless of initial cholesterol levels. Blood pressure lowering is also recommended for all patients, with a target of <130/80 mmHg, starting after the patient is clinically stable.
Practical Takeaway: The treatment protocols are highly consistent. The main practical difference may be observed at a local level, where RCP-affiliated stroke networks might implement more aggressive early DAPT strategies based on the latest evidence, even before a formal NICE update.
Management of Special Situations
Crescendo TIA and High-Risk Patients
- NICE: Defines crescendo TIA as two or more TIAs in a week. It recommends urgent admission and consideration for acute antiplatelet therapy and urgent imaging/angiography.
- RCP: Manages these patients as a medical emergency, often advocating for immediate admission to a hyperacute stroke unit. Treatment may include intravenous antiplatelet agents or heparin in select cases, and expedited workup for carotid intervention if a large artery stenosis is suspected.
Carotid Artery Stenosis
- Both Guidelines: Agree that for patients with 50-99% carotid stenosis (using NASCET criteria), carotid endarterectomy (CEA) should be performed. The key is timing.
- Timing of Intervention: The consensus, strongly reflected in RCP audits and NICE quality standards, is that CEA should be performed within 14 days of symptom onset, and ideally within 1-2 days for the highest-risk patients. The RCP's SSNAP audit actively monitors and pressures services to achieve this target.
Practical Clinical Flow: A Synthesis
For a clinician in a UK emergency department or primary care setting, a pragmatic synthesis of both guidelines yields this flow:
- Suspected TIA: Refer immediately for specialist assessment. Do not delay.
- Triage: Use ABCD² score (per NICE) but augment with clinical judgement for high-risk features (e.g., AF, prolonged symptoms) as per RCP philosophy. Aim for same-day assessment for high-risk patients.
- Assessment & Imaging: Patient seen in specialist TIA clinic or hyperacute stroke unit. Urgent brain imaging (MRI DWI preferred) arranged to confirm diagnosis and exclude mimics.
- Immediate Treatment: Start secondary prevention immediately after diagnosis and exclusion of haemorrhage: Clopidogrel 300mg stat, then 75mg daily. Atorvastatin 80mg. Arrange urgent carotid Doppler if anterior circulation symptoms.
- Long-term Management: Optimise blood pressure, manage AF with anticoagulation, and provide lifestyle advice. Refer for CEA if significant symptomatic carotid stenosis is identified.
Frequently Asked Questions (FAQs) for Clinicians
1. Which guideline should I follow if my local trust protocol differs?
Local trust protocols are developed to reconcile national guidance with local resources and are the primary document you should follow. They often represent a hybrid of NICE and RCP recommendations. If a protocol seems outdated, this should be raised through clinical governance channels.
2. Is the ABCD² score still relevant?
Yes, but with caveats. NICE mandates its use, making it a necessary part of the referral process. However, as per RCP sentiment, it should not override clinical judgement. A patient with an ABCD² score of 3 but with known atrial fibrillation should be considered high-risk.
3. What is the single biggest practical difference between NICE and RCP?
The operational model. NICE outlines the "what" – a specialist clinic within 24 hours for ABCD² ≥4. The RCP, through SSNAP, defines and audits the "how" – the integration into hyperacute stroke services, pushing for a culture where TIA is treated with the same urgency as stroke.
4. When should I refer a TIA patient directly to the hyperacute stroke unit instead of the TIA clinic?
Refer directly to the hyperacute stroke unit if the patient has ongoing or fluctuating symptoms, symptoms within the last few hours, or is exhibiting "crescendo" features (multiple events in a short period). Local protocols will specify exact criteria.
5. How long should dual antiplatelet therapy (DAPT) be continued?
NICE currently recommends clopidogrel monotherapy. The use of DAPT (aspirin and clopidogrel) for a short duration (e.g., 21 days) is based on trial evidence and may be incorporated into local RCP-influenced pathways for high-risk non-cardioembolic TIA. This is an area of evolving practice, and clinicians should check their local protocol.
Source Links
- NICE Guideline CG248 (Last updated May 2024): NICE CG248
- Royal College of Physicians Sentinel Stroke National Audit Programme (SSNAP): Sentinel Stroke National Audit Programme (SSNAP)
- RCP National Clinical Guideline for Stroke (2016, with subsequent updates): RCP London stroke guidelines