16.2 Secondary Prevention, TIA, Carotid Surgery & Intracranial Haemorrhage

4. Secondary Prevention & Post-Stroke Care

Acute Ischaemic Stroke (CT Brain Excludes Haemorrhage)
  │
  ├── Immediate Antiplatelet: Aspirin 300 mg daily for 14 days
  │     (If thrombolysed: delay aspirin until 24-hour follow-up CT excludes haemorrhagic transformation)
  │
  ├── Dysphagia Assessment: Formal bedside swallow screen BEFORE any oral intake
  │
  ├── Long-term Antithrombotic Strategy:
  │     ├── Non-cardioembolic (sinus rhythm): Switch at day 14 to Clopidogrel 75 mg once daily indefinitely
  │     └── Cardioembolic (Atrial Fibrillation): Anticoagulation (DOAC) initiated at 5–14 days post-stroke
  │
  ├── Lipid Lowering: High-intensity Atorvastatin 80 mg daily (delayed until >48h or upon discharge)
  │
  └── Carotid Imaging: Carotid Doppler ultrasound for anterior circulation stroke/TIA

• Antiplatelet Regimen: Aspirin 300 mg daily orally, enterally, or rectally for 14 days. In thrombolysed patients, aspirin is withheld for 24 hours until a follow-up CT scan confirms absence of significant haemorrhagic transformation. Long-term secondary prevention: Clopidogrel 75 mg monotherapy indefinitely (first-line under NICE guidelines). If clopidogrel is contraindicated or not tolerated, use aspirin 75 mg daily combined with modified-release dipyridamole 200 mg twice daily (or aspirin 75 mg monotherapy).
• Lipid Management: Initiate high-intensity statin therapy with Atorvastatin 80 mg once daily irrespective of baseline cholesterol level (aim for $\ge 50%$ reduction in LDL-cholesterol or LDL $< 1.4\text{ mmol/L}$). Statin therapy is typically started once acute dysphagia is managed and the patient is medically stabilized (within 48 hours to discharge).
• Anticoagulation in Atrial Fibrillation: Anticoagulation with a Direct Oral Anticoagulant (DOAC: apixaban, edoxaban, rivaroxaban, or dabigatran) is the gold standard for non-valvular AF. Crucial MRCP Timing Rule: Do NOT start full anticoagulation immediately in acute ischaemic stroke due to excessive risk of haemorrhagic transformation. In practice, aspirin 300 mg is used initially, and oral anticoagulation is introduced according to infarct size:
  • TIA: Start DOAC immediately or at day 1.
  • Mild stroke (NIHSS $< 8$, small infarct): Start DOAC at day 3–5.
  • Moderate stroke (NIHSS 8–15): Start DOAC at day 7.
  • Severe stroke (NIHSS $> 15$, large cortical infarct): Delay DOAC until day 14, often repeating CT brain before initiation to exclude haemorrhagic transformation.

5. Transient Ischaemic Attack (TIA) & Carotid Endarterectomy

• Definition: A transient episode of neurological dysfunction caused by focal brain, spinal cord, or retinal ischaemia, without acute tissue infarction on neuroimaging.
• Emergency Management Pathway:
  1. Immediate Antiplatelet: Administer Aspirin 300 mg stat immediately unless contraindicated, continuing 300 mg daily until specialist neurovascular assessment.
  2. Urgent Neurovascular Clinic: High-risk TIA presentations must be assessed by a specialist stroke team within 24 hours of symptom onset.
  3. Urgent Carotid Duplex Ultrasound: Mandated for all patients with anterior circulation TIA or non-disabling ischaemic stroke who are potential candidates for carotid intervention.
• Carotid Endarterectomy (CEA) Indications (NASCET Criteria):
  • Symptomatic stenosis 70–99%: Strongest benefit; absolute risk reduction of stroke exceeds $16%$. CEA should be performed urgently within 7 days of symptom onset.
  • Symptomatic stenosis 50–69%: Moderate benefit; consider CEA, especially in male patients, elderly patients, or those with hemispheric (rather than retinal) symptoms.
  • Symptomatic stenosis $< 50%$: No surgical benefit; manage with intensive medical therapy.
  • Complete occlusion (100% stenosis): Surgical intervention is contraindicated; manage medically.
• DVLA Driving Regulations (UK Law):
  • Group 1 (Car and Motorcycle): Must stop driving for at least 1 month following a stroke or TIA. They may resume driving after 1 month without notifying the DVLA if clinical recovery is satisfactory and no residual functional neurological deficits impair vehicle control. If significant neurological deficit persists at 1 month, they must notify the DVLA.
  • Group 2 (Bus and Lorry / HGV): Must stop driving immediately, notify the DVLA, and cannot drive for a minimum of 1 year.

6. Intracerebral Haemorrhage & Subarachnoid Haemorrhage

Spontaneous Intracerebral Haemorrhage (ICH)

• Emergency Management: Non-contrast CT confirms hyperdense intraparenchymal haematoma.
• Blood Pressure Lowering: In patients presenting within 6 hours of onset with systolic BP 150–220 mmHg, initiate rapid intensive BP reduction within 1 hour targeting systolic BP 130–140 mmHg (using IV labetalol or nicardipine). Avoid reducing systolic BP below 130 mmHg.
• Anticoagulant Reversal: Administer immediate reversal agents:
  • For Warfarin: Four-Factor Prothrombin Complex Concentrate (4F-PCC, 25–50 IU/kg) plus Intravenous Vitamin K 10 mg.
  • For Dabigatran: Idarucizumab 5 g IV.
  • For Factor Xa Inhibitors (Apixaban, Rivaroxaban): Andexanet alfa or 4F-PCC (50 IU/kg).
• Neurosurgical Consultation: Indicated for infratentorial (cerebellar) haematomas $> 3\text{ cm}$ with brainstem compression or hydrocephalus (mandates urgent surgical evacuation), or supratentorial lobar haematomas with impending herniation.

Aneurysmal Subarachnoid Haemorrhage (SAH)

• Presentation: Rupture of intracranial saccular (berry) aneurysm (most commonly anterior communicating artery ~30%, posterior communicating artery ~25%, or MCA bifurcation ~20%). Sudden, catastrophic "thunderclap" headache ("struck by a bat"), peaking within seconds, accompanied by neck stiffness, vomiting, photophobia, and transient loss of consciousness. Oculomotor (CN III) nerve palsy with pupil dilatation strongly points to a posterior communicating artery aneurysm.
• Diagnostic Protocol:
  1. Immediate Non-contrast CT Head: Sensitivity exceeds $99%$ within 6 hours of onset. Demonstrates hyperdense blood in the basal cisterns, sylvian fissures, and interhemispheric fissure.
  2. Lumbar Puncture (LP): Mandated if CT head is negative or equivocal, or performed $> 6\text{ hours}$ post-onset. Critical Timing Rule: LP must be performed at least 12 hours after symptom onset to allow enzymatic breakdown of lysed erythrocytes into bilirubin. CSF Spectrophotometry showing xanthochromia (bilirubin absorbance peak at 476 nm) confirms subarachnoid haemorrhage and differentiates it from a traumatic tap (which clears across tubes and shows only oxyhaemoglobin).
• Management:
  • Oral Nimodipine: $60\text{ mg}$ every 4 hours for 21 days; acts as a neuroprotective dihydropyridine calcium channel blocker that prevents delayed cerebral ischaemia (vasospasm) and improves neurological survival.
  • Aneurysm Securing: Early intervention within 24–48 hours to prevent catastrophic rebleeding. Endovascular coiling is the preferred first-line modality (ISAT trial showed superior disability-free survival compared to open surgical clipping).