What is Mechanical Thrombectomy?
Mechanical thrombectomy (also called endovascular thrombectomy or clot retrieval) is an emergency, minimally invasive procedure used to treat acute ischaemic stroke caused by a large vessel occlusion (LVO). It involves navigating a specialised stent-retriever device or aspiration catheter through the blood vessels to the blocked artery in the brain, physically grabbing the clot and removing it restoring blood flow within minutes.
This procedure has revolutionised stroke care. Prior to its advent, outcomes from large vessel strokes were often devastating. Today, when performed by an experienced interventional radiologist like Dr. Gurucharan S Shetty within the treatment window, thrombectomy can result in dramatic neurological recovery even in patients presenting with complete paralysis or inability to speak.
Who is a Candidate for Thrombectomy?
Mechanical thrombectomy is indicated for patients with acute ischaemic stroke caused by occlusion of a major cerebral artery such as the internal carotid artery (ICA), middle cerebral artery (MCA), or basilar artery. It is most effective when performed within 6 hours of symptom onset, although in selected patients with salvageable brain tissue identified on imaging, the treatment window can be extended up to 24 hours. Candidates typically present with a significant neurological deficit, often reflected by an NIHSS score of 6 or higher, indicating a large area of brain at risk. Imaging with CT or MRI should demonstrate a large vessel occlusion with a substantial amount of still-viable brain tissue, known as the penumbra. The procedure is suitable for patients who have already received intravenous thrombolysis or for those who are not eligible for clot-dissolving medications.
How is the Procedure Performed?
- Rapid Imaging: A CT scan with CT angiography is performed immediately to confirm LVO and assess how much brain tissue is salvageable.
- Groin Access: Under local anaesthesia or general anaesthesia, a catheter is inserted through the femoral artery in the groin.
- Navigating to the Clot: Using live X-ray (fluoroscopy) and contrast dye, a microcatheter is advanced through the carotid and cerebral arteries to reach the site of the blockage.
- Clot Removal: A stent retriever is deployed across the clot it interlocks with the clot and both are withdrawn together. Alternatively, a large bore aspiration catheter suctions the clot directly.
- Confirmation: A final angiogram confirms successful vessel recanalization and restoration of blood flow to the brain.
- Post-procedure Care: The patient is monitored in the neuro-ICU. Neurological status is assessed every hour. Most patients show improvement within hours of successful recanalization.