The mantra ‘time is brain’ doesn’t include the idea that you can salvage a small percentage of patients at 39 hours - Gregory Albers MD
image by: Dr. Ramon Reyes, MD
When I started as a resident at Mass General, there was little we could do for severe stroke patients except manage the medical complications. As a result, there was a feeling of hopelessness among doctors; we noted the tragedy and moved on.
But that started to change when researchers began experimenting with drugs that could dissolve the clots that block the brain arteries and cause ischemic stroke (when oxygen is cut off to part of the brain). This new line of research was inspired by the successes of using clot-dissolving drugs to treat heart attack patients. However, there was one major difference. Clot-dissolving drugs can be deadly, causing bleeding into brain tissue already damaged by a stroke; this is a minimal risk in the heart attack patient.
In 1993, after years of painstaking work, our institute, the National Institute of Neurological Disorders and Stroke, announced that an intravenous, clot-dissolving medication improved outcomes after ischemic stroke. This was the first FDA treatment for acute stroke, and in the generation since, we have witnessed a revolution in the treatment for this devastating yet common disorder.
How common? Stroke is the number one cause of severe long-term disability and the fifth leading cause of death. And more than 795,000 people will have new strokes this year.
The treatment discovered in 1993, tPA, acts as a clot buster, and, if given into a vein within the first three hours after a stroke, can reduce or even completely prevent disability. We saw stroke patients walk out of the hospital within hours after their treatment—something that would have been unthinkable just a few years before.
However, we faced tremendous challenges after this announcement. Medical professionals had to rethink their approach to stroke. Shortening the time to treatment was absolutely critical, but most neurologists were not practicing in emergency settings; there was no test to show whether the neurologic symptoms were due to a stroke; emergency department doctors were cautious using a drug that carried risk of bleeding into the brain; and the ambulance systems were not built to get the stroke patient to a treatment center ASAP.
Despite the hurdles, the new treatment changed the medical system. There are now more than 1,200 stroke centers, paramedics know where to go with a stroke patient, and advances in brain scanning have helped identify a stroke in progress.
The public also needed education. Few knew the symptoms of stroke, or that it was treatable, or that it was an emergency! So we rolled out a campaign called Know Stroke. By capitalizing on the public’s awareness of heart attack, we coined the term “brain attack” for stroke and taught people the symptoms.
Recently, there have been more exciting breakthroughs in acute stroke treatment. As mentioned earlier, tPA was most effective at dissolving the small clots that caused small strokes. To treat the more severe strokes, investigators and device companies tested special catheters that could grab and pull the clot directly out of the blood stream. Now these devices save people from the most devastating outcomes.
Another advance is acute stroke brain scanning. By scanning quickly through the brain after a dye injection, we can pinpoint the blockage, identify the brain regions starved for blood flow, and get a good sense of how much brain is already damaged. Because brain cells are dying every second in a stroke, it is always critical to get treatment as quickly as possible. However, two studies found that with the advanced brain scanning technologies, we could identify patients who benefited from treatment even up to 16 hours after stroke onset.
Of course the best way to deal with stroke is to prevent it from happening. And controlling high blood pressure is the most important way to do this. A recent NIH study called SPRINT MIND showed that intensive lowering of blood pressure led to decreases both in death due to heart disease and in the risk of developing cognitive impairment, a form of early dementia. But we had to get the word out. So we developed a public health campaign, MindYourRisks, to drive home the key role blood pressure control plays to the millions who don’t know they’re at risk.
Stroke can happen at any age, but there are some key factors that can increase risk, including high blood pressure, smoking, being overweight, and diabetes. In addition, African Americans experience stroke at a much higher rate compared to whites.
In the early 1960s, researchers noticed very high rates of stroke and cardiovascular disease in the southeastern part of the country, which became known as the “Stroke Belt.” But why? Since 2003, NINDS has funded the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, which has been looking at factors that increase stroke risk. To get a deeper dive into the study, go to http://www.regardsstudy.org/.
In 2017, NIH funded $331 million of research on stroke, including learning what happens to brain cells during stroke, potential therapies, and novel approaches in rehabilitation. For those who survive a stroke, the general rule is that the brain circuits try to repair themselves. However, we don’t understand enough about how this rewiring occurs. In addition, most of our treatment advances help those with stroke due to a blockage in a blood vessel. We also need to focus more on those with stroke due to bleeding into the brain.
...let’s celebrate our successes: Stroke has fallen from the third to the fifth leading cause of death, thousands have received emergency stroke treatment, and the medical profession has changed and risen to the challenge. But also look forward to the discoveries yet to be made in prevention and treatment. I hope that in the generation to come we will get even closer to understanding and controlling this tragic and largely preventable disorder.
Walter J. Koroshetz, We've Made Astonishing Progress in Treating Stroke, Scientific American, May 7, 2019.