New guidelines on primary stroke prevention from AHA/ASA

Susan Jeffrey

December 03, 2010

Dallas, TX - The American Heart Association (AHA)/American Stroke Association (ASA) has released new guidelines for the primary prevention of stroke, both ischemic and hemorrhagic [1].

Dr Larry B Goldstein (Duke University Medical Center, Durham, NC) chaired the writing group for the new document.

In 1999, the AHA set 2010 as a goal for decreasing mortality from heart disease and stroke by 25%, Goldstein said in an interview. That goal was achieved early, in 2008, probably due to better prevention strategies, he said.

Of more than 790 000 strokes that do occur each year, 75% of those are first events, "so prevention is particularly important." Since 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, is published online December 2, 2010 in Stroke.

Points of interest

Goldstein pointed to areas of particular interest in the document.

Lifestyle f actors . 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, Goldstein emphasized.

"Those types of lifestyles are associated with about an 80% 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."

 
There's virtually nothing that we can do with medicine or interventions of any kind that's going to have that kind of impact .
 

Second hand s moke. 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 those data just aren't available," he said. "It seems to be true for coronary heart disease, and in communities that institute clean indoor-air acts, for example, the rate of hospital admission for acute MI 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 the data yet."

E mergency-departme nt s creening . Visits to the emergency room 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," 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.

Asymptomatic carotid artery stenosis. An area that has become more complex, he noted, is deciding whether to recommend revascularization for patients who have asymptomatic carotid stenosis.

The data supporting carotid endarterectomy or stenting over best medical therapy are aging, and medical therapies have become more effective, potentially narrowing the margin of potential benefit from intervention, 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-r isk s ubjects . Another recommendation of note is that aspirin is not advocated for low-risk subjects. Aspirin is used "ubiquitously," 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, defined as a 10-year risk of 6% to 10%, to outweigh the risks associated with treatment.

Atrial f ibrillation . Of note, the section on atrial fibrillation does not yet make recommendations on use of new anticoagulants in late-stage clinical testing or on dabigatran (Pradaxa, Boehringer Ingelheim), a direct thrombin inhibitor recently approved by the US Food and Drug Administration for stroke prevention in the setting of AF. 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, 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"

Dr Philip B Gorelick (University of Illinois College of Medicine, Chicago) served as a reviewer on the new document.

He said 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 over the past four years.

"Goldstein and colleagues are to be congratulated for providing an important and comprehensive update of guidelines for prevention of a first stroke," 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 emergency department as well as 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."

Goldstein reports he has received research grants from the National Institutes of Health and the AHA/Burger Center , received speaker ' s - bureau fees /honoraria from Bayer, served as a consultant or advisory - board member for Pfizer and A bbott, and served as a steering- committee member for the SPARCL trial sponsored by Pfizer. Gorelick reports receiving honoraria/speaker's - bureau fees f rom Boehringer Ingelheim and has been a consultant/advisory- board member for diaDe xus, Boehringer Ingelheim, B ristol- M yers S quibb/ Sanofi, Pfizer, and Daiichi Sankyo. Disclosures for the other writing group members are l isted in the paper.

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