More patients could be eligible for critical treatments to remove or dissolve blood clots that cause strokes, according to a new treatment guideline issued by the American Heart Association/American Stroke Association.

The guideline, based on the most recent science available, was published in the Association’s journal Stroke, and released during the American Stroke Association’s International Stroke Conference 2018, the premier global meeting for researchers and clinicians dedicated to the prevention and treatment of stroke.

A major new recommendation increases the window of time for selected patients who are eligible to have blood clots mechanically removed from vessels supplying the brain. Mechanical clot removal is only advisable in clots that block large vessels. The guideline recommends that large vessel strokes can safely be treated with mechanical thrombectomy up to 16 hours after a stroke in selected patients. Under certain conditions, based on advanced brain imaging, some patients may have up to 24 hours. The previous time limit was 6 hours.

During mechanical thrombectomy, a physician uses a device within a catheter (a thin tube threaded inside an artery) to grab and remove the clot. The procedure has proven effective in limiting the risk of disability when used to treat blockages in the larger vessels leading to the brain.

“The expanded time window for mechanical thrombectomy for appropriate patients will allow us to help more patients lower their risk of disability from stroke,” said William J. Powers, MD, the guideline writing group chair and professor of neurology at the University of North Carolina in Chapel Hill, North Carolina. “That’s a big deal. That’s potentially a lot more people who could benefit, and it has completely changed the landscape of acute stroke treatment.”

The American Heart Association/American Stroke Association, in conjunction with The Joint Commission, have created a new level of hospital certification for Thrombectomy-Capable Stroke Centers to identify hospitals that meet rigorous standards for performing mechanical endovascular thrombectomy.

Another new recommendation broadens the eligibility for administering a clot-busting IV drug called alteplase—a type of tissue plasminogen activator (tPA)—the only FDA-approved clot-dissolving treatment for ischemic stroke. Previously, patients with mild strokes were not eligible for clot-busting treatment, but new research suggests it could help some of these patients. The guideline says doctors should weigh the risks and benefits in individual patients, because the drug can decrease disability when given promptly and appropriately.

“It potentially increases the number of people the getting intravenous clot-busting treatment,” Powers said.

An unchanged but important guideline recommendation is the need for fast action when a person shows the symptoms of a stroke.

“It’s better to call 911 than to have somebody drive a stroke patient to the hospital. Hospitals are set up to immediately treat acute stroke patients arriving by ambulance,” Powers said. “In many patients, getting to the hospital quickly is the difference between living a life of disability or one free of disability from stroke.”

For hospitals that don’t have access to neurologists or emergency room doctors trained to use the clot-dissolving medication, the guidelines recommend connecting those hospitals to stroke experts in real time via videoconferencing, Powers said. Research shows patients treated via this “telestroke” approach received the same quality of care as they would have at stroke centers with a neurologist on call.

Stroke is the second-leading cause of death in the world and a leading cause of adult disability. The new guidelines cover acute ischemic strokes, the most common type of stroke, which occur when a blood clot blocks an artery leading to the brain and reduces or stops blood flow. Someone in the US has a stroke about once every 40 seconds and stroke kills about 133,000 Americans each year. Ischemic stroke accounts for about 87% of all strokes.

The guideline is based on a review of over 400 peer-reviewed published studies. The studies were examined by a group of experts in stroke care and are the most comprehensive recommendations for treating ischemic stroke issued since 2013.