When someone has a heart attack, the saying is “Time is muscle.” Getting appropriate care as soon as possible is crucial. It’s the same with a stroke. Most strokes are the result of a clot that cuts off the supply of blood to the brain. In strokes, it’s “Time is brain” because the sooner treatment is given, the better the outcome.
One of the main treatments for stroke is the removal of a clot with a device called a stent retriever that grabs hold of a blood clot and draws it out of the body. Current wisdom is that this procedure must be done within six hours of the stroke. A new study at UCLA however shows that there is a bit more time than what most would think.
Published in the Journal of the American Medical Association, the study showed that treatment with these clot grabbers is still beneficial for up to 7.3 hours post onset. Dr. Jeffrey Saver, director of the UCLA Comprehensive Stroke Center and the study’s lead author stated, “Extending the time window for therapy will let us help more patients, including patients who were not able to get to a hospital right away because the stroke started while they were asleep or made them unable to call for help.”
Time is still important, however and the team stressed that knowing the signs of stroke and seeking emergency help immediately is key. The study, which was done by combining from five clinical trials involving a total of 1,287 people, including the SWIFT PRIME trial also led by Saver, showed that these devices improved outcomes for people who had large artery strokes, where the blockage occurs in a major blood vessel. The researchers looked closely at the three factors: the time interval between onset and treatment, the type of treatment given and the outcome for the patient. With this data they also found that for every six minutes treatment is not administered the risk of a permanent disability goes up by 1%. In the US out of the approximately 15 million stroke cases per year, about 5 million of them will result in permanent disability for the patient
While not every patient is treated with a stent retriever and not every patient is given clot busting drug therapy, the study did show that patients treated with retrievers plus standard medical therapy were less likely to be disabled three months after surgery than people who only received medical therapy. Looking at the outcomes, of course patients treated within two hours had the best results but even those who did not receive treatment until almost 8 hours after the stroke still benefitted from the dual therapy approach, although at a lower rate. The first stent retrievers were invented at UCLA is 2004, and the university continues to evaluate the data on the device.
In future studies, the wants to add brain imaging techniques to determine if it is possible to further sift out a smaller group of people that may benefit from stent retrieval at even later time intervals, between 7 and 24 hours. Check out the video for more information on the study.
Sources: UCLA Comprehensive Stroke Center
, Journal of the AMA
, UCLA Newsroom