Endovascular thrombectomy, often referred to as EVT, is a medical procedure used in the emergency treatment of stroke. Acute ischemic strokes occur when a blood clot blocks an artery in the brain, interrupting blood flow. EVT physically removes these clots. It restores blood flow to affected brain regions, limiting potential damage and improving patient outcomes.
Endovascular Thrombectomy Explained
Endovascular thrombectomy is a minimally invasive surgical procedure focused on treating acute ischemic stroke, specifically those caused by a large vessel occlusion (LVO). The primary objective of EVT is to mechanically remove this blood clot from the blocked brain artery. This mechanical removal is distinct from clot-dissolving medications like tissue plasminogen activator (tPA), which work by chemically breaking down the clot.
Restoring blood flow promptly is important to prevent further brain damage. EVT directly addresses the blockage, aiming to re-establish circulation to the affected area as quickly as possible. This approach has shown significant improvements in outcomes for patients experiencing ischemic stroke.
The EVT Procedure
The EVT procedure begins with patient preparation, which typically involves anesthesia and imaging scans to confirm the clot’s location. A neurointerventionalist, a specialist physician, then inserts a thin, flexible tube called a catheter, usually into an artery in the groin or wrist. Using real-time X-ray imaging, known as fluoroscopy or angiography, the physician carefully guides the catheter through the body’s blood vessels up to the blocked artery in the brain.
Once the catheter reaches the clot, specialized devices are deployed through it to remove the obstruction. The most common methods involve using stent retrievers or aspiration devices. A stent retriever is a small, mesh-like cage that expands to capture the clot, which is then pulled out along with the device. Aspiration devices, on the other hand, work by suctioning the clot directly. The procedure aims to restore blood flow, and the entire process typically takes between one and two hours.
Who Qualifies for EVT?
Not all stroke patients are candidates for EVT; specific criteria determine eligibility. Imaging techniques are used to confirm the presence and location of such a blockage. A time-sensitive factor is the window for treatment, which is typically within 6 hours of symptom onset. However, in select cases, based on advanced imaging that identifies salvageable brain tissue, this window can extend up to 16 to 24 hours after the last known normal time. Other considerations for eligibility include the patient’s age (generally 18 years or older), stroke severity as measured by scales like the NIH Stroke Scale, and pre-existing functional status. Rapid assessment and diagnosis are important because earlier treatment generally leads to better outcomes.
What to Expect After EVT
Following an EVT procedure, patients are typically monitored closely in a neuro intensive care unit or high-dependency ward. This allows medical teams to observe for any immediate complications and manage blood pressure and other vital signs. The aim of EVT is to improve neurological function and reduce long-term disability. Many patients experience significant improvement in their stroke symptoms.
While EVT generally leads to positive outcomes, potential complications, though rare, can occur. These might include bleeding at the access site, vessel damage, or, in some instances, new clot formation. Recovery is an ongoing process that often involves comprehensive rehabilitation, including physical, occupational, and speech therapy, tailored to the individual’s needs to help regain lost functions and adapt to any persistent challenges.