Treating acute ischemic stroke patients with endovascular therapy within 2.5 hours significantly improves functional outcomes, according to a new study published online in the journal Radiology.

When the brain tissue is deprived of oxygen-bearing blood, it can lead to long-term functional impairments like difficulty walking or speaking. The new research highlights the importance of getting stroke patients to the correct level of care as quickly and efficiently as possible.

Recent advancements have been made in the field including intravenous plasminogen activators (IV t-PA) to break down blood clots. Stent retrievers have also been introduced, which are mesh devices that are threaded through a blood vessel in the groin to blocked arteries in the head with X-ray guidance to remove the clot.
The researchers at the University of Calgary evaluated data on patients who were treated with both IV t-PA and stent retrievers as part of the Solitaire With the Intention For Thrombectomy as PRIMary Endovascular Treatment (SWIFT PRIME) Trial.

They found that restoring blood flow to the brain within 2.5 hours of when the symptoms first occurred was associated with minimal or no disability, also known as function independence, in 91 percent of the patients.

The likelihood of functional independence was 10 percent higher in patients treated within 2.5 hours compared to those treated between 2.5 and 3.5 hours. Every hour after the 3.5 hours lead to a 20 percent lower likelihood of functional independence.

With a projected global market value of $9.4 million by 2022, according to Grand View Research, mobile stroke units are seeing rapid adoption. The world’s first unit with a hospital-grade CT angiography scanner was introduced in late March at the University of Tennessee College of Medicine in Memphis.

At first glance, this would seem to be a solution to having stroke patients treated within the 2.5 hour window, but Dr. Mayank Goyal, the study’s lead author, sees several potential issues with it.

“Overall, mobile stroke units have the potential to further improve stroke workflow and help in getting the correct patient to the correct hospital,” he said. “However, it will likely work only if there are multiple stroke ambulances and multiple teams, [for example,] in a city like New York.”

If there is only one stroke ambulance for the whole city, then issues will arise when the ambulance is in one part of the city and the stroke patient is on the opposite side. The other problem is when the stroke ambulance gets a call from someone in the neighborhood, but has to decide if they should attend the call or let it be handled by the regular ambulance.

The type of personnel that will be on-board the stroke ambulance — including a physician, nurse or paramedic — needs to be ironed out. Economic considerations will also come into play, said Goyal.

He believes that the solution is to track endovascular workflow times and provide feedback. Every step in the work up and treatment of the patients should be weighed against the time spent and the potential benefit.

Two-thirds of the patients in the study were transferred directly to the centers that were capable of endovascular therapy and the rest went to a primary stroke center. Those who were admitted to the stroke center lost about two hours in overall workflow.

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