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Ischaemic Stroke

National Clinical Guideline for Stroke 2023 Edition. NICE Guideline [NG128] Stroke and transient ischaemic attack in over 16s: diagnosis and initial management. Last updated: Apr 2022

Guidelines

In order of priority:
  1. Refer to hyperacute stroke service
  2. Perform history and examination + exclude hypoglycaemia + document NIHSS score
  3. Non-contrast head CT to exclude intracerebral haemorrhage
  4. Once intracerebral haemorrhage is excluded → determine eligibility for thrombolysis and/or thrombectomy
    • If patient is eligible for thrombolysis → perform thrombolysis (and delay aspirin)
    • If patient is NOT eligible for thrombolysis → give aspirin 300mg immediately

If eligible for both thrombolysis and thrombectomy → thrombolysis should be given without delay and activate thrombectomy protocol at the same time. 

Admit all suspected stroke patients directly to hyperacute stroke service

1st line and most important investigation: non-contrast head CT within 1 hour to exclude intracerebral haemorrhage

Further imaging:
  • Diagnostic uncertainty → MRI brain with stroke-specific sequences
 
  • Potentially eligible for thrombolysis and/or thrombectomy
    • CT / MR perfusion (alternative: MRI measuring DWI-FLAIRDiffusion-weighted imaging (DWI)–fluid-attenuated inversion recovery (FLAIR) mismatch)
    • CT angiogram from aortic arch to skull vertex 

 

If the patient is likely eligible for thrombectomy (e.g. high NIHSS and low modified Rankin score), it is common to order a CT stroke protocol (sequence of scans including non-contrast CT → CT perfusion → CT angiography), which excludes intracerebral haemorrhage and gives the relevant information needed to assess eligibility for thrombectomy.

Admit all suspected stroke patients directly to hyperacute stroke service

The following management options only applies once intracerebral haemorrhage has been excluded.

 

If CT excludes haemorrhage, and the clinical picture is consistent with acute stroke → you treat as ischaemic stroke.

This is because, head CT is often normal in the first few hours therefore it is not possible to definitively diagnose or rule out ischaemic stroke.

Aspirin 300mg should be offered ASAP once
  • Intracerebral haemorrhage has been excluded AND
  • Patient is not undergoing thrombolysis

If the patient is dysphagic → enteral / rectal tube

 

If the decision is made to treat the patient with thrombolysis, aspirin 300mg should only be given 24 hours after thrombolysis (and once repeat imaging excludes haemorrhage). 

Do NOT give aspirin 300mg before thrombolysis.

  • Onset of symptoms <4.5 hours 
  • Last known to be well >4.5 hours earlier if
    • Thrombolysis can be started between 4.5-9 hours or known onset OR within 9 hours of midpoint of sleep for wake-up stroke, AND
    • NeuroimagingCT / MR perfusion, or MRI DWI-FLAIR mismatch shows potential to salvage brain tissue

 

It is sufficient to just learn that <4.5 hours from onset of symptoms as the eligibility criteria for thrombolysis.

It is very unlikely for any medical school exams or the UKMLA to test a student's knowledge on the 2nd eligibility listed above.

Ensure BP <185/110 mmHg before initiating thrombolysis. 

Agent of choice: IV alteplase / tenecteplase 
  • Drug class: tPA (tissue plasminogen activator) 
  • MoA: tPA attaches to the fibrin on the clot surface → activates fibrin-bound plasminogen into plasmin → plasmin breaks down molecules to dissolve the clot 

Contraindications outlined by the National Clinical Guideline for Stoke:
  • BP >185/110 mmHg (BP should be lowered prior thrombolysis)
  • Intracranial haemorrhage (should be excluded with head CT)
  • Known ↑ risk of bleeding
    • Recent major surgery
    • Significant head trauma
    • Known bleeding disorders
    • Patiens taking anticoagulant therapy beyond safe therapeutic parameters

 

It is important to rule out contraindications for thrombolysis while taking a history from a patient with suspected stroke.

NICE recommends:

Offer thrombectomy in proximal anterior circulation occlusion (confirmed on CTA / MRA) if:
  • <6 hours of symptom onset, OR
  • Last known to be well 6-24 hours (including wake-up strokes) + there is potential to salvage brain tissue

Consider thrombectomy in proximal posterior circulation occlusion ​Basilar / posterior cerebral artery(confirmed on CTA / MRA) if:
  • Last known to be well up to 24 hours (including wake-up strokes), AND
  • There is potential to salvage brain tissue

NICE recommends that thrombectomy is favoured in:
  • Pre-stroke modified Rankin scale <3 (i.e. good pre-stroke functional status)
  • NIHSS >5 (i.e. stroke causing disabling neurological deficits)
 
 

Decisions regarding thrombectomy are complicated and are made by neurologists. The general indications for thrombectomy can be categorised into 2 main domains:

  • Clinical factors
    • Disabling / severe neurological deficits (high NIHSS)
    • Good pre-stroke functional status (low modified Rankin scale)
  • Imaging factors
    • Proximal occlusion (i.e. large vessel occlusion) (indicated by angiography)
    • If there is potential to salvage brain tissue (indicated by CT / MR perfusion)

NICE recommends considering decompressive hemicraniectomy within 48 hours if ALL of the following:
  • Clinical features that suggest MCA infarct + NIHSS score >15
  • ↓ Level of consciousness + ≥1 on NIHSS item 1a
  • MCA territory infarct >50% on CT
 
 

Rationale: in malignant MCA infarction, extensive cerebral oedema can develop rapidly. Decompressive hemicraniectomy prophylactically prevents cerebral oedema from raising ICP and reduces risk of ICP. 

Offer:
  • High-intensity statin (e.g. atorvastatin 80mg) 
  • Antithrombotic treatment (antiplatelet or anticoagulation)

Choice of antiplatelet vs anticoagulation as long-term antithrombotic treatment depends on the cause of stroke

  • Aspirin 300mg OD continued for 2 weeks after stroke onset
 
  • After 2 weeks → clopidogrel 75mg OD lifelong
    • Alternative: aspirin 75mg OD

 

If the patient is treated with thrombolysis, antiplatelet should be delayed until 24 hours after AND once repeat imaging excludes haemorrhage.

  • Aspirin 300mg OD before initiating anticoagulation
 
  • Start anticoagulation  within 2 weeks of stroke onset
    • 1st line for non-valvular AF: DOAC
    • 1st line for valvular AF / with mechanical heart valve: warfarin

References

Author: Adams Lau
Reviewer:
Last Edited: 28/02/25