Mechanical Thrombectomy for Ischaemic Stroke

🧠 Mechanical thrombectomy is a life-saving endovascular procedure used to remove large clots from cerebral arteries in acute ischemic stroke. ⚡ It has revolutionized stroke care by rapidly restoring blood flow, improving survival, and reducing long-term disability when performed promptly.

📖 About

• Definition: Endovascular removal of intracranial clots in large vessel occlusion (LVO) stroke.
• History: Modern thrombectomy emerged in 2015 with stent retrievers & aspiration catheters after multiple landmark RCTs.
• Purpose: Rapid recanalization → salvage brain tissue → improve functional outcome.

📑 Evidence & Number Needed to Treat (NNT)

• Landmark RCTs:
  • MR CLEAN, ESCAPE, REVASCAT, SWIFT PRIME, EXTEND-IA → all showed clear benefit over IV thrombolysis alone.
• Meta-analyses: Confirm thrombectomy is superior to medical therapy alone for LVO strokes.
• NNT:
  • ~2–3 to achieve functional independence (mRS 0–2 at 90 days).
  • ~6–10 to prevent one death.
• Guidelines: AHA, ESO & NICE endorse thrombectomy for eligible patients.

🧾 Pre-Thrombectomy Assessment

• Clinical: NIHSS to quantify deficit severity (higher scores suggest LVO).
• Imaging:
  • NCCT: exclude haemorrhage.
  • CTA: confirm large vessel occlusion.
  • CTP/MR perfusion: assess penumbra vs infarct core.
• Labs: FBC, coagulation profile, renal function (contrast safety), glucose.
• Eligibility:
  • Time window: ≤6h (up to 24h in selected patients by perfusion imaging).
  • LVO: ICA, MCA (M1/M2), basilar artery.
  • Adequate salvageable brain tissue.
  • No major contraindications (extensive infarct, severe comorbidity).

🎯 Indications

• Acute ischemic stroke with confirmed LVO.
• Within time window (6–24h depending on imaging).
• Favourable penumbra-to-core ratio on perfusion studies.

🛠️ Devices

• Stent Retrievers: Solitaire, Trevo → ensnare clot & pull it out.
• Aspiration Catheters: ADAPT → suction clot out.
• Combined Techniques: Stent retriever + aspiration (Solumbra approach).

⚙️ Procedure

• Access: Usually femoral artery → navigate catheter to clot.
• Retrieval: Deploy retriever/aspiration → remove clot (multiple passes if needed).
• Verification: Angiography confirms recanalization (TICI 2b–3 = success).
• Closure: Sheath removal & haemostasis.

⚠️ Complications

• Intracranial haemorrhage (ICH).
• Vessel injury: dissection or perforation.
• Distal embolization of clot fragments.
• Access site haematoma/AV fistula.
• Reperfusion injury.
• Contrast nephropathy (rare).

📈 Outcomes

• Recanalization success in >80–90% with modern devices.
• Significant functional improvement (mRS 0–2 at 90 days in 45–60%).
• Mortality reduction compared to IV thrombolysis alone.
• “Time is brain”: benefit falls with delay.

🩺 Post-Procedure Care

• ICU/HDU monitoring for neuro status & haemodynamics.
• Follow-up CT/MRI to assess reperfusion & exclude haemorrhage.
• Early rehabilitation: physio, OT, speech therapy.
• Secondary prevention: antiplatelet/anticoagulation as indicated.

🚀 Recent Advances

• Better imaging → extended treatment windows (DAWN, DEFUSE 3 trials).
• Next-gen aspiration catheters with improved suction.
• Trials of posterior circulation thrombectomy (basilar artery occlusion).

✅ Conclusion

Mechanical thrombectomy is now gold standard therapy for eligible LVO strokes. Success depends on rapid recognition, efficient pathways, expert intervention, and careful post-stroke care. Each minute saved → better neurological recovery.

📚 References

• Goyal M, Menon BK, et al. Lancet 2016;387:1723–31.
• Albers GW, Marks MP, et al. NEJM 2018;378:708–18.
• NINDS – Mechanical Thrombectomy
• World Stroke Organization – Guidelines