Stroke Thrombolysis

Related Subjects: |Acute Stroke Assessment (ROSIER&NIHSS) |Atrial Fibrillation |Atrial Myxoma |Stroke Thrombolysis |Anterior Choroidal Artery Ischaemic Stroke |Causes of Stroke |Ischaemic Stroke |Cancer and Stroke |Hypertension |Small Vessel Disease |CADASIL |CARASIL

⏱️ Time is brain! Acute ischaemic stroke is a medical emergency. IV thrombolysis should be given as fast and as safely as possible in eligible patients, and mechanical thrombectomy should be pursued urgently when indicated.

🧠 Core Principle

• Exclude intracranial haemorrhage urgently with brain imaging.
• If the patient is eligible, give IV thrombolysis within 4.5 hours of symptom onset / last known well.
• Do not delay transfer for thrombectomy while waiting to see the effect of thrombolysis.
• Selected patients with wake-up stroke or presentation beyond 4.5 hours may still be eligible if advanced imaging shows salvageable brain tissue.

✅ Current Thrombolytic Drugs

• Tenecteplase is now a NICE-recommended option for acute ischaemic stroke.
• Alteplase remains an option.
• In practice, local stroke services usually use the least expensive suitable option in line with NICE guidance.

💉 Drug Protocols

• Tenecteplase
  • 0.25 mg/kg IV bolus (maximum 25 mg)
  • Given as a single IV bolus over about 5–10 seconds
  • Much simpler logistically than alteplase
• Alteplase
  • 0.9 mg/kg (maximum 90 mg)
  • 10% of the total dose as an initial IV bolus
  • 90% infused over 60 minutes

🧾 Who Should Be Considered for IV Thrombolysis?

• Clinical diagnosis of acute ischaemic stroke causing a disabling neurological deficit
• Intracranial haemorrhage excluded on urgent imaging
• Treatment can start within 4.5 hours of symptom onset / last known well
• Given within a well-organised stroke service with trained staff, imaging, monitoring, and re-imaging available

🕒 Extended / Imaging-Selected Thrombolysis

• Selected patients may be considered for alteplase when:
  • treatment can start between 4.5 and 9 hours from known onset, or
  • they have wake-up stroke and treatment can start within 9 hours of the midpoint of sleep, or
  • MRI shows DWI–FLAIR mismatch suggesting salvageable tissue
• This depends on local imaging capability and stroke specialist assessment.

🚫 Major Contraindications / Reasons Not to Thrombolyse

• Intracranial haemorrhage on imaging
• Clinical suspicion of subarachnoid haemorrhage, even if CT is initially normal
• Blood pressure >185/110 mmHg despite treatment
• Current major bleeding or very high bleeding risk
• Recent major surgery / major trauma / significant invasive procedure where bleeding risk is unacceptable
• Known coagulation abnormality or anticoagulant effect that is unsafe for thrombolysis
• Very low platelets or major uncontrolled metabolic abnormality mimicking stroke
• Stroke mimic or another diagnosis judged more likely than acute ischaemic stroke

⚠️ Important Practical Points

• Age alone is not a reason to withhold thrombolysis.
• Stroke severity alone is not an absolute exclusion.
• Minor symptoms may still justify treatment if the deficit is disabling (for example aphasia, hemianopia, severe hand weakness, disabling ataxia).
• Seizure at onset is not an absolute exclusion if persistent deficits are thought to be due to stroke rather than purely post-ictal change.
• Posterior circulation stroke can be thrombolysed if otherwise eligible.

🖥️ Imaging Checklist

• Non-contrast CT head immediately if the patient may be eligible for reperfusion therapy
• If thrombectomy may be indicated, perform CT angiography after the non-contrast CT
• Add CT perfusion (or MR equivalent) if thrombectomy may be indicated beyond 6 hours or in wake-up stroke
• Large established infarction reduces the benefit and increases the risk of reperfusion therapy
• Note: A hyperdense artery sign supports large vessel occlusion and is not a contraindication to thrombolysis

🧪 Key Bedside / Lab Checks Before Thrombolysis

• Capillary blood glucose — exclude hypoglycaemia as a mimic
• Platelet count if thrombocytopenia is suspected
• Coagulation tests if anticoagulation or bleeding disorder is possible
• Weight for drug dosing
• Blood pressure
• NIHSS and pre-stroke modified Rankin score

🫀 Blood Pressure Management

• Before thrombolysis: reduce BP to <185/110 mmHg if otherwise eligible
• Monitor closely during and after treatment
• Persistent severe hypertension after treatment increases the risk of haemorrhagic transformation

🧲 Mechanical Thrombectomy

• Offer thrombectomy as soon as possible and within 6 hours for:
  • acute ischaemic stroke
  • proximal anterior circulation large-vessel occlusion
  • usually with pre-stroke mRS <3 and NIHSS >5
• Offer thrombectomy up to 24 hours in selected patients with:
  • proximal anterior circulation occlusion
  • favourable advanced imaging showing salvageable tissue
• Consider thrombectomy up to 24 hours in selected posterior circulation occlusions as well.
• If eligible for thrombectomy and thrombolysis, give IV thrombolysis first unless contraindicated.

📋 First 24 Hours After IV Thrombolysis

• Close neurological and haemodynamic monitoring
• Avoid unnecessary invasive procedures if possible
• No antiplatelet or anticoagulant therapy in the first 24 hours
• Repeat brain imaging before starting antiplatelet therapy
• Start antiplatelet treatment after 24 hours once significant haemorrhage has been excluded

⚠️ Complications

• Symptomatic intracranial haemorrhage — suspect if headache, vomiting, acute hypertension, reduced consciousness, or worsening neurological deficit
• Orolingual angioedema, particularly with alteplase and especially in patients on ACE inhibitors
• Systemic bleeding
• Reperfusion injury / haemorrhagic transformation

🚨 If Deterioration Occurs During or After Thrombolysis

• Stop the infusion if alteplase is still running
• Urgent senior stroke / neurology review
• Repeat urgent brain imaging
• Manage airway, breathing, circulation, and blood pressure
• Follow local haemorrhage-reversal / complication protocols immediately

📖 Cases - Stroke Reperfusion Therapy

• Case 1 - Classic anterior circulation stroke 🧠: A 68-year-old man presents 90 minutes after onset with right hemiparesis and expressive dysphasia. CT head shows no haemorrhage. Diagnosis: acute ischaemic stroke within the standard reperfusion window. Management: IV thrombolysis plus stroke unit care.
• Case 2 - Posterior circulation stroke 🚨: A 55-year-old woman presents with sudden vertigo, vomiting, diplopia, and ataxia. CTA shows basilar artery occlusion. Management: IV thrombolysis if eligible and urgent transfer for mechanical thrombectomy.
• Case 3 - Wake-up stroke 🕒: A 72-year-old man wakes with left hemiparesis. Advanced imaging shows a small infarct core and salvageable tissue. Diagnosis: imaging-selected wake-up stroke. Management: consider reperfusion therapy according to local hyperacute stroke protocol and imaging findings.

Teaching Point 🩺:
Modern acute ischaemic stroke care is about rapid reperfusion. Use non-contrast CT to exclude haemorrhage, add CTA when thrombectomy may be needed, and use advanced imaging for selected late-presenting or wake-up strokes. 💉 Tenecteplase is now a NICE-recommended thrombolytic option within 4.5 hours, while alteplase remains an option. 🧲 Large-vessel occlusion should trigger urgent assessment for mechanical thrombectomy.

📚 References

• NICE TA990 – Tenecteplase for treating acute ischaemic stroke (2024)
• NICE NG128 – Stroke and TIA in over 16s: diagnosis and initial management
• National Clinical Guideline for Stroke (UK and Ireland, 2023)
• Tenecteplase (Metalyse 25 mg) SmPC
• Alteplase (Actilyse) SmPC