New Guidelines on Primary Stroke Prevention From AHA/ASA
December 2, 2010 — The American Heart Association/American Stroke Association (AHA/ASA) has released new guidelines for the primary prevention of stroke, both ischemic and hemorrhagic.
Larry B. Goldstein, MD, professor of medicine (neurology) and director of the Duke Stroke Center at Duke University Medical Center in Durham, North Carolina, chaired the writing group for the new document.
In 1999, AHA set a goal for 2010 of decreasing mortality from heart disease and stroke by 25%, Dr. Goldstein toldMedscape Medical News. That goal was achieved early, in 2008, probably due to better prevention strategies, he said.
Of more than 790,000 strokes that occur each year, 75% of those are first events, "so prevention is particularly important." Because risk factors for both ischemic and hemorrhagic strokes largely overlap, he said, "in this guideline we address primary prevention of stroke, not just ischemic stroke, so that's one significant change."
The new guideline, affirmed as an "educational tool for neurologists" by the American Academy of Neurology, was published online December 2 and will appear in the December issue of Stroke.
Points of Interest
The document is thorough and comprehensive, with 68 pages and almost 800 references, and Dr. Goldstein pointed to areas of particular interest.
• Lifestyle Factors: The writing committee evaluated the gamut of new and emerging risk factors, modifiable and nonmodifiable. What remains first among strategies for primary stroke prevention is modification of lifestyle factors, including physical activity, not smoking, moderate alcohol consumption, maintaining a normal body weight, and eating a low-fat diet high in fruits and vegetables, Dr. Goldstein emphasized.
"Those types of lifestyles are associated with about an 80% — that's 8-zero percent — lower risk of a first stroke, and that's true for both men and women," he said. "There's virtually nothing that we can do with medicine or interventions of any kind that's going to have that kind of impact, so that I think is of paramount importance."
• Secondhand Smoke: Cigarette smoking is an established risk factor for stroke, but the new recommendations suggest that avoiding environmental tobacco smoke is also a "reasonable" strategy, he noted.
"We don't know that limiting that exposure decreases the risk because that data just isn't available," he said. "It seems to be true for coronary heart disease and communities that institute clean indoor air acts, for example, the rate of hospital admission for acute [myocardial infarction] drops precipitously in the year after those measures are taken. We believe the same should be true for stroke, although again we don't have that data yet."
• ED Screening: Visits to the emergency department (ED) may be a valuable opportunity to screen for and treat stroke risk factors, including smoking cessation strategies, cholesterol and blood pressure monitoring, or atrial fibrillation screening and treatment implementation, the new guidelines note.
"As we know, a fairly high proportion of Americans don't have healthcare insurance, and they don't seek regular preventive care," Dr. Goldstein said. "They get their healthcare usually because of an acute illness of some kind by going to the emergency department.
"Even though emergency departments are currently overwhelmed with patients receiving their primary care there for these types of illnesses, it's also an opportunity to identify risk factors and potentially have patients referred for appropriate prevention," he said.
Although ED-based smoking cessation programs and interventions, atrial fibrillation identification, and evaluation for anticoagulation are recommended, and ED population screening for hypertension and drug abuse is considered "reasonable," the document adds that the effectiveness of screening, brief intervention, and referral for treatment of diabetes and lifestyle risk factors in the ED setting is "not established."
• Asymptomatic Carotid Artery Stenosis: An area that has become more complex, he noted, is deciding whether to recommend revascularization for patients who have carotid stenosis that is still asymptomatic.
The data supporting carotid endarterectomy or stenting over best medical therapy is aging, and medical therapies have become more effective, making the margin of potential benefit from intervention potentially more and more narrow, Dr. Goldstein said. More recent studies have compared surgery with stenting without a medical therapy arm, so data using contemporaneous controls on which to make an evidence-based decision are not currently available.
"For asymptomatic people — for symptomatic people it's a completely different story — when and how to do these interventions has become a much more difficult decision," he said.
"Selection of asymptomatic patients for carotid revascularization should be guided by an assessment of comorbid conditions and life expectancy, as well as other individual factors, and should include a thorough discussion of the risks and benefits of the procedure with an understanding of patient preferences," the document states.
• Aspirin in Low-Risk Subjects: Another recommendation of note is that aspirin is not advocated for low-risk subjects. Aspirin is used "ubiquitously," Dr. Goldstein notes, but "doesn't seem to offer any particular protection and even in very low doses does carry side effects, so it's important for people to understand what their risks are for heart disease and for stroke to determine whether aspirin may have some benefit."
Use of aspirin to prevent cardiovascular events, including but not limited to stroke, is recommended for those at sufficiently high risk to outweigh the risks associated with treatment defined as a 10-year risk of 6% to 10%.
• Atrial Fibrillation: Finally, of note is that the section on atrial fibrillation does not yet make recommendations on use of new anticoagulants now under investigation, including dabigatran (Pradaxa, Boehringer Ingelheim), a direct thrombin inhibitor that was recently approved by the US Food and Drug Administration for stroke prevention in the setting of atrial fibrillation. Studies considered in practice guidelines must be published in peer-reviewed journals, and the RE-LY trial comparing dabigatran and warfarin was not available when this document was being written, although they are discussed, Dr. Goldstein explained.
What may happen in the near future is an intermediate advisory to address this, he noted. "Besides the direct thrombin inhibitors there are factor Xa inhibitors that have also been tested, but the trials haven't been published yet, just presented at a meeting, and we'll likely wait until all of those are available before deciding if and when to publish a practice advisory."
Revision 'Long Overdue'
Philip B. Gorelick, MD, MPH, John S. Garvin professor and head of the Department of Neurology and Rehabilitation and director of the Center for Stroke Research at the University of Illinois College of Medicine in Chicago, served as a reviewer on the new document.
He told Medscape Medical News that AHA/ASA guidelines for primary prevention were last updated in 2006, making them "long overdue for revision" given the substantial new data that have been generated during the past 4 years.
"Goldstein and colleagues are to be congratulated for providing an important and comprehensive update of guidelines for prevention of a first stroke," Dr. Gorelick said. "Sections on diabetes, dyslipidemia, and atrial fibrillation provide much new and needed guidance as does the section on asymptomatic carotid artery stenosis."
Several new sections have been added to this guideline, including one on primary prevention in the ED and new information about strategies for adherence, he added. "The emergency department is an important gateway to the healthcare system, and key preventive measures can be initiated there."
This guideline, he says, "is highly recommended reading for healthcare professionals who take care of patients at risk for stroke."
Dr. Goldstein reports he has received research grants from the National Institutes of Health and the AHA/Burger Center, received speakers' bureau/honoraria from Bayer, served as a consultant or advisory board member for Pfizer and Abbott, and served as a steering committee member for the SPARCL trial sponsored by Pfizer. Dr. Gorelick reports receiving honoraria/speaker's bureau for Boehringer Ingelheim and has been a consultant/advisory board member for diaDexus, Boehringer Ingelheim, BMS Sanofi, Pfizer, and Daiichi Sankyo. Disclosures for all other writing group members appear in the paper.
Stroke. Published online December 2, 2010.