The immediate hours after suffering an ischemic stroke are critical. The clot that occurs within a blood vessel must be removed within 3-6 hours in order to prevent long term disability, brain damage or death.
For years, the only FDA-approved treatment for removing clots has been a tissue plasminogen activator, or tPA. The medicine, delivered intravenously, travels to the clot and dissolves and restores blood flow to the brain. When an occlusion forms in a major vessel, however, tPA has been effective in less than a third of all patients. Scientists for years have been looking for reinforcements that could aid tPA in eliminating main-stem clots as quickly and as safely as possible. The result is the Stent Retriever.
The stent retriever is used in a procedure called a mechanical thrombectomy in which a wire-caged device is sent to the site of the blocked vessel. A catheter is threaded via the femoral artery to the occlusion. When it reaches the site, the stent is deployed, a 3D mesh tube unfolds and seizes the clot. The stent is then threaded back out of the body and blood flow is restored.
The clinical trials for mechanical thrombectomies have been a resounding success. All of the studies found that patients whose clots were removed via stent retriever had speedier recoveries and improved chances of regaining independence when compared to those with strokes treated by tPA alone. First generation stent retrievers were approved by the FDA in 2012, but the second generation is being touted as a tool every stroke unit will be equipped with by the end of 2016, and one that will be used in over 60,000 patients by the turn of the decade.
Where Are They Now
In 2015, the American Heart Association/American Stroke Association (AHA/ASA) published new stroke treatment guidelines that recommended the use of stent retriever technology in conjunction with IV-tPA as a first-line for eligible patients. In 2016, analysis confirmed that stent retrievers were very successful with extremely low complication rates and low symptomatic intracranial hemorrhage. In January 2018, the AHA/ASA released even newer guidelines recommending an increased treatment window for clot removal. The window was expanded, recommending intervention with a stent retriever up to 24 hours post-stroke. These new guidelines made the Top 10 list for 2019 as number 3: “Expanded Window for Acute Stroke Intervention.”