Health & Medicine

Stroke Treatment Window Can Be Up To 7.3 Hours, Earlier Treatment Can Lead To Lesser Disability After Stroke

Johnson D
First Posted: Sep 29, 2016 03:13 AM EDT

Most people have an understanding that when someone suffers from an acute ischemic stroke, life-saving surgeries to remove blood clots in the brain should be performed immediately. However, according to a new study, the window for clot removal surgeries may be longer than what was originally thought.

Endovascular thrombectomy is an emergency procedure to remove a clot, has recently been developed and has already been used numerous times. The American Stroke Association said that the procedure should be done within six hours after symptoms of stroke are seen to decrease the amount of disability the patient might experience after. However, as per the report of ABC News, the latest study analysis showed that the time for treatment could be prolonged up to 7.3 hours.

"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," said Dr. Jeffrey Saver, director of the UCLA Comprehensive Stroke Center and the study's lead author.

The researchers also discovered that there is a one percent increase in the risk of people ending up being disabled for every 6-minute delay which highlights the importance to seek medical treatment as soon as stroke symptoms are experienced. The study also analyzed the relationship between the onset of the stroke, the length of time until the blockage was treated and how it would affect the patient, reported Science Daily.  

Researchers for this study mainly used a newer generation of stent retrievers, which were cleared for use in 2012. First, doctors insert the small mesh tubes through an artery in the leg to the blockage in the artery that takes blood to the brain. Next, they open the mesh tubes in the middle of the clot and then extract the stent and the clot to restore blood flow to the brain. The new study combines data from five clinical trials which included a total of 1,287 people together with the SWIFT PRIME led by Dr. Saver. It showed how these devices improved results for people with acute ischemic strokes caused by large vessel blockage. The researchers also analyzed the relationship between time from onset of the blockage to treatment and outcome among these patients.

According to news-medical.net, the researchers were able to find that people who were treated earlier with the retrievers along with standard medical therapy had lesser chances of being disabled three months after undergoing the surgery, compared to those who only received medical therapy. Researchers also stated that the greatest results were seen if the procedure was done within the first two hours of a stroke. However, those treated up to 7.3 hours after a stroke continued to show a lesser benefit, researchers added.

Earlier treatment is better than later treatment to restore blood flow and prevent or limit damage to the brain, Saver noted. "It is important for the public to know the critically important relationship between time to treatment and outcome, so they know to activate the 911 system as soon as possible when they detect stroke symptoms in themselves or friends, family and co-workers," he said. "And it is important to reorganize regional systems of stroke care to ensure that ambulances transport appropriate patients to hospitals that perform this procedure quickly and safely."

Meanwhile, the people involved in the trials were mostly seen at academic medical centers, so there are still questions as to whether the same results can be seen if treatments were done at non-academically affiliated medical centers. Other factors could alter the results may include differences in trial entry criteria and patient characteristics. It was also said that these results may not apply to people who did not qualify for the trials.

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