Study IDs Risk Factors for Recurrent Stroke Despite Aggressive Medical Management
A study led by Dr. Michael Waters, director of the Stroke Program and Neurovascular Division at Barrow, has been named one of the top 10 heart and stroke research advances of 2016 by the American Heart Association.
The study, published online in JAMA Neurology on Jan. 4, aimed to identify factors associated with high risk for recurrent stroke in people with symptomatic intracranial stenosis — the narrowing of an artery in the brain — despite aggressive medical management.
The study analyzed patients who were part of the medical management group of the SAMMPRIS Trial, which was published in the New England Journal of Medicine in 2011. The SAMMPRIS Trial separated 451 patients who had experienced a recent transient ischemic attack (TIA) or stroke related to intracranial stenosis into two groups. One group received aggressive medical management alone, and the other received aggressive medical management plus stenting.
The SAMMPRIS Trial found that aggressive medical therapy was more effective than stenting for preventing recurrent stroke in patients with symptomatic intracranial stenosis. This aggressive management included treating and controlling high cholesterol, high blood pressure, and diabetes. It also incorporated a lifestyle modification program.
However, even though the medical group did better than the stenting group, 15 percent of patients in the medical group still experienced a recurrent stroke during a median follow-up of 32.7 months.
“In spite of best medical management, there is a subset of patients at very high risk for repeat stroke,” Dr. Waters told Medscape. “We desperately need better treatments for this cohort.”
The study led by Dr. Waters attempted to shed a light on those risk factors. Conducted from November 2014 to June 2015, it looked at baseline demographic features, vascular risk factors, qualifying event for enrollment into the study, brain imaging, and angiographic features.
The analysis identified three factors associated with increased risk for recurrent stroke in the medical group: an old stroke in the area of the narrowed artery on baseline imaging, a stroke rather than a TIA as an enrollment-qualifying event, and not being on a statin — a drug used to lower bad cholesterol levels — at the time of enrollment. The highest-risk patients were those who had an old stroke in the area of the stenosis, particularly in the internal carotid artery — a major blood vessel in the neck that supplies blood to the brain.
“We would like to use this data to draft a proposal for another clinical trial in the subset of patients at very high risk for repeat stroke,” Dr. Waters said. “Medical management did not reduce risk to less than 1 in 3 for these patients. Medical therapy alone will not be adequate to protect this subgroup from suffering another stroke.”
In spite of best medical management, there is a subset of patients at very high risk for repeat stroke. We desperately need better treatments for this cohort.
-Dr. Michael Waters, Director of Stroke Program and Neurovascular Division
The analysis also identified subgroups at particularly low risk for recurrent stroke while undergoing aggressive medical management: patients presenting with a TIA alone and patients who were already in the target for exercise when they entered the study. The target for physical activity was a Physician-Based Assessment and Counseling for Exercise (PACE) score of 4 to 8. A PACE score of 4 is equivalent to vigorous exercise less than three times per week or moderate exercise less than five times per week. These results supplement risk factor analyses from the SAMMPRIS Trial showing that exercise during follow-up was the most important determinant of a good outcome in the group that received medical management alone.
Dr. Waters also said it is still worth investigating new-generation stenting technology for these high-risk patients.
“Look what’s happened with acute stroke: endovascular therapy failed so many times, but now it is the standard of care,” he said. “As technology improved, so did the benefits. If we do find a technology that works for the highest-risk patients, it is possible that it could also be used in a lower-risk population in time.”