Mechanical thrombectomy is the physical removal of an occluding clot from a large brain artery during an acute ischemic stroke — and it is among the most consequential advances in modern medicine. For large-vessel occlusion (LVO) stroke, restoring flow by extracting the clot dramatically improves the odds of a functional recovery compared with clot-dissolving drugs alone. This article outlines the two core techniques — stent retrievers and aspiration — the evidence and time windows that govern their use, and where they sit in the acute stroke pathway.
The Problem: Large-Vessel Occlusion
When a major intracranial artery (such as the middle cerebral or internal carotid) is blocked, roughly two million neurons are lost per minute of ischemia — the origin of "time is brain." Intravenous thrombolysis alone often fails to open large proximal clots. Mechanical thrombectomy addresses this directly by reaching the clot with a catheter and removing it, and a series of landmark 2015 trials followed by later time-window studies established it as standard of care for eligible LVO patients.
Stent Retrievers
A stent retriever is a self-expanding mesh delivered through a microcatheter across the clot and deployed within it. The mesh expands into the thrombus, is left briefly to engage it, then withdrawn — pulling the captured clot out with it, often alongside aspiration. Stent retrievers made modern thrombectomy reliable and remain a foundation of the procedure. INVAMED's KinG intracranial revascularization device is a stent-retriever-class device within the neurovascular intervention portfolio.
Aspiration Thrombectomy (ADAPT)
The aspiration-first approach advances a large-bore catheter directly to the face of the clot and applies suction to ingest it — no stent retriever needed in many cases. Trials found a direct-aspiration-first-pass technique non-inferior to stent-retriever-first for reperfusion, and the two are frequently combined (a "combined" or Solumbra technique) when either alone does not achieve first-pass success. Aspiration relies on large-bore access and reliable suction, delivered through systems like INVAMED's DOVI aspiration catheter paired with a dedicated aspiration pump.
Navigating to the Clot
Neither technique works without getting there. The clot sits at the end of a long, tortuous path from the groin or wrist through the aortic arch and into the cerebral circulation, and the supporting cast — guide catheters, distal access catheters, and microcatheters — determines whether the retriever or aspiration catheter reaches its target in time. Access is often the rate-limiting step in a fast, well-drilled thrombectomy.
Time Windows and Selection
Eligibility combines time from onset and imaging. Within roughly 6 hours of a suitable LVO, thrombectomy is offered on clinical and non-invasive imaging criteria; from about 6 to 24 hours, advanced perfusion imaging selects patients whose brain tissue is still salvageable. The consistent theme is that patient selection by imaging, and speed of reperfusion, drive outcomes — faster and better-selected means better function at 90 days.
Frequently Asked Questions
What is the difference between a stent retriever and aspiration thrombectomy?
A stent retriever expands into the clot and pulls it out; aspiration applies suction through a large-bore catheter to ingest the clot. Both are effective and are often combined.
How long after a stroke can thrombectomy be done?
Generally up to about 6 hours on standard criteria, and selected patients up to 24 hours when advanced perfusion imaging shows salvageable brain tissue.
Does thrombectomy replace clot-dissolving drugs?
No — eligible patients often receive intravenous thrombolysis as well; thrombectomy specifically addresses large-vessel clots that drugs alone frequently cannot open.
Why is speed so important in stroke thrombectomy?
Because roughly two million neurons are lost per minute of large-vessel occlusion — faster reperfusion means more preserved brain and better recovery.
Related on INVAMED
Companion: microcatheters and neurovascular access. Patient hub: stroke & neurovascular conditions. Portfolio: neurovascular interventions.
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