Nav: Home

Low blood flow in back of brain increases risk of recurrent stroke

December 21, 2015

Patients who have had a stroke in the back of the brain are at greater risk of having another within two years if blood flow to the region is diminished, according to results of a multicenter study led by researchers at the University of Illinois at Chicago. These stroke patients are the most likely to benefit from risky intervention to unblock arteries, and they can be identified using a new MRI-based technology developed at UIC. The findings are published in the journal JAMA Neurology.

The vertebrobasilar region in the back of the brain is responsible for locomotion and balance. Vertebrobasilar strokes can be devastating, causing partial or total paralysis. They account for 30 percent to 40 percent of all strokes, or about 200,000 cases per year in the U.S.

Stroke patients found to have narrowing of the blood vessels in the back of the brain caused by atherosclerosis can have angioplasty, a procedure to open blocked arteries, but the procedure carries its own risks. And because blockages don't always correlate to locally reduced blood flow - thought to be the real culprit in raising stroke risk - researchers wanted to better understand the relationship between arterial blockages, blood flow, and recurrent strokes.

"Having a blockage present in a blood vessel doesn't always correlate to low blood flow," says Dr. Sepideh Amin-Hanjani, professor of neurological surgery at the UIC College of Medicine and principal investigator on the study. "There can be a blockage and flow can be normal, if other nearby blood vessels are able to compensate."

She and her colleagues wanted to try to identify which stroke patients are at highest risk for further strokes and so might benefit from angioplasty despite the risks of the procedure.

They followed 72 adult patients who had a stroke or temporary symptoms of a stroke, known as a transient ischemic attack, in the back of the brain and who also had at least 50 percent blockage of the arteries in that part of the brain. The patients were followed for an average of 22 months at five academic medical centers as they continued receiving standard care for their condition from their neurologists.

Participants were evaluated for reduced blood flow in the back of the brain using NOVA, or Noninvasive Optimal Vessel Analysis, a software program that can quantify the volume, velocity, and direction of blood flowing through any major vessel in the brain using standard MRI equipment. The NOVA software was developed at UIC by Dr. Fady Charbel, professor and head of neurological surgery, who is a co-author of the new study.

One-fourth of the study participants were found to have diminished blood flow in the back of the brain, which turned out to be a significant predictor of subsequent stroke. These patients had 12- and 24-month stroke-free survival rates of 78 percent and 70 percent, respectively, compared to 96 percent and 87 percent for patients with normal blood flow.

"At one year, the risk for patients with low blood flow was about five times as high as risk for patients without low flow in the back of the brain," Hanjani said. For these patients, the benefits of angioplasty probably outweigh the risks.

"About three-quarters of patients didn't have low blood flow in the vertebrobasilar region - other arteries are doing the job of ensuring that proper blood flow is reaching that area - and these patients would not benefit from treatments aimed at opening the vessels, such as angioplasty - in fact, the procedure would put these patients at unnecessary risk," Hanjani said.

The ultimate goal is to find what treatments might be most effective for each patient, Hanjani said.

The UIC Office of Technology Management helped to transfer the NOVA technology to a startup. VasSol, Inc. further developed the technology into a product with an improved user interface, adding functionality and applicability.

Hanjani and her colleagues hope that the ease of identifying the high-risk group using NOVA will enable further study of the condition and the evaluation of new therapies to further reduce the risk of recurrent stroke.

The study sites that enrolled patients were UIC; Washington University of St. Louis; the University of California, Los Angeles; Columbia University in New York; and the University of Toronto/Toronto Western Hospital.
-end-
Other co-authors on the JAMA Neurology paper are Dr. Dilip Pandey, Dr. Xinjian Du, DeJuran Richardson, Dr. Keith Thulborn, Dr. Victor Aletich and Linda Rose-Finnell of UIC; Dr. Mitch Elkind of Columbia University; Dr. Greg Zipfel and Dr. Colin Derdeyn of Washington University; Dr. David Liebeskind of UCLA; Dr. Frank Silver of the University of Toronto; Dr. Scott Kasner of the University of Pennsylvania; Dr. Louis Caplan of Beth Israel Deaconess Hospital and Harvard Medical School; and Dr. Philip Gorelick of Michigan State University.

The study was funded by the National Institutes of Health/National Institute of Neurological Disorders and Stroke (grant R01 NS 059745). Additional funding was provided by the Dr. Ralph and Marian Falk Research Trust Foundation. Material research support was provided by VasSol, Inc.

University of Illinois at Chicago

Related Stroke Articles:

How to help patients recover after a stroke
The existing approach to brain stimulation for rehabilitation after a stroke does not take into account the diversity of lesions and the individual characteristics of patients' brains.
Kids with headache after stroke might be at risk for another stroke
A new study has found a high incidence of headaches in pediatric stroke survivors and identified a possible association between post-stroke headache and stroke recurrence.
High stroke impact in low- and middle-income countries examined at 11th World Stroke Congress
Less wealthy countries struggle to meet greater need with far fewer resources.
Marijuana use might lead to higher risk of stroke, World Stroke Congress to be told
A five-year study of hospital statistics from the United States shows that the incidence of stroke has risen steadily among marijuana users even though the overall rate of stroke remained constant over the same period.
We need to talk about sexuality after stroke
Stroke survivors and their partners are not adequately supported to deal with changes to their relationships, self-identity, gender roles and intimacy following stroke, according to new research from the University of Sydney.
Standardized stroke protocol can ensure ELVO stroke patients are treated within 60 minutes
A new study shows that developing a standardized stroke protocol of having neurointerventional teams meet suspected emergent large vessel occlusion (ELVO) stroke patients upon their arrival at the hospital achieves a median door-to-recanalization time of less than 60 minutes.
Stroke affects more than just the physical
A new study looks at what problems affect people most after a stroke and it provides a broader picture than what some may usually expect to see.
Stroke journal features women's studies on how gender influences stroke risk, treatment and outcomes
Many aspects of strokes affect women and men differently, and four articles in the American Heart Association's journal Stroke highlight recent research and identify future research needs.
Too few with stroke of the eye are treated to reduce future stroke
Only one-third of 5,600 patients with retinal infarction, or stroke in the eye, underwent basic stroke work-up, and fewer than one in 10 were seen by a neurologist.
Juvenile stroke: Causes often not known
Strokes without a definitive identifiable cause account for up to 50 percent of juvenile strokes.
More Stroke News and Stroke Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.