Ischemic Stroke is the most common type and accounts for 87% of all strokes.  It occurs due to blockage of blood vessel usually by a blood clot or by fatty deposits. In treatment of Acute Ischemic Stroke (AIS), the primary goal is to quickly restore blood flow by dissolving the clot through clot bursting medication or by physically removing the clot through intra-arterial treatment. The clot bursting medication such as intravenous tissue plasminogen activator (t-PA) can be given up to 4.5 hours of symptom onset. Some patients may not be eligible to receive t-PA due to illness, blood disorders, recent surgery or concurrent use of other medication which can interfere in the effects of t-PA. Due to narrow treatment window of t-PA and its effectiveness in small percentage of patients who have large vessel occlusion, the optimal treatment of AIS is Intra-arterial treatment which is a technique of navigating catheters into the brain blood vessels and either dissolve the clot by giving local intra-arterial t-PA, or by physically removing the clot which is called Mechanical Thrombectomy. (see figure):
Thrombectomy can be done by using aspiration devices or by using Retrievers with maximum effectiveness when it is performed within 6 hours of onset of stroke symptoms. (see figure) In some studies, mechanical thrombectomy has shown good clinical outcome if it is done within 8 hours of stroke onset.  The effectiveness of mechanical thrombectomy beyond 8 hours of stroke onset is unknown.
The treatment of Ischemic Stroke is dependent and the primary goal of mechanical thrombectomy is to restore blood flow by removing the blockage from affected brain blood vessel.
Figure : Mechanical thrombectomy of acute ischemic stroke due to blood clot (Image courtesy of Stryker Neurovascular)
Figure :Acute Ischemia Treatment progression by mechanical thrombectomy using retriever (Image courtesy of Stryker Neurovascular)
Figure : Left ICA, MCA and ACA clot on cerebral angiogram (A) Before mechnical thrombectomy (B) After mechnical thrombectomy
Figure : Blood clot removed by stent retriever
- American Heart Association. Heart Disease and Stroke 2017 Statistics At-a-glance.
- Wahlgren, N., Macho, J. Killer M., Liebeskind D., Jansen O. Final Results from the Trevo Study (Thrombectomy Revascularization of large Vessel Occlusions in acute ischemic stroke). International Stroke Conference, 2012.