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Stroke Rounds: New Prevention Guidelines Favor Mediterranean Diet
Published: Oct 30, 2014 | Updated: Oct 30, 2014
By Salynn Boyles, Contributing Writer, MedPage Today
Action Points
Note that joint guidelines from the American Heart and American Stroke Associations clarify issues relating to stroke prevention on the population level.
Among the most notable guidelines, the associations call for increased efforts to ban smoking in public places.
Following a Mediterranean diet, monitoring high blood pressure at home, and increasing efforts to ban smoking in public places top the list of new recommendations for reducing stroke risk from the American Heart Association/American Stroke Association.
Revised stroke prevention guidelines also expand the list of acceptable oral anticoagulant options for patients with nonvalvular atrial fibrillation beyond warfarin to include dabigatran, apixaban, and rivaroxaban.
“The selection of antithrombotic agent should be individualized on the basis of patient risk factors (particularly risk for intracranial hemorrhage), cost, tolerability, patient preference, potential for drug interactions, and other clinical characteristics, including time International Normalized Ratio (INR) is in therapeutic range for patients taking warfarin,” the writing committee wrote in the journal Stroke, published online Oct. 29.
Lead author James F. Meschia, MD, of the Mayo Clinic, Jacksonville, told MedPage Todaythat adding the warfarin substitutes may increase the use of anticoagulant treatments for patients who need them.
“We aren’t saying that warfarin is not effective,” he said. “It is clearly effective, but because of the need for close monitoring and (side effects) many patients are reluctant to take it and doctors may be reluctant to prescribe it.”
90% of Stroke Risk Modifiable
Stroke is the fourth leading cause of death in the U.S., and the leading cause of functional impairment.
Among patients age 65 or older, 26% are dependent on others to perform their daily activities and 46% have cognitive deficits 6 months after their strokes, according to statistics released this year by the American Heart Association (AHA).
“Primary prevention is particularly important because >76% of strokes are first events. Fortunately, there are enormous opportunities for preventing stroke,” Meschia and colleagues wrote.”
A 2010 study that examined risk factors for stroke among 6,000 people living in 22 countries found that 10 potentially modifiable risk factors explain 90% of stroke risk.
The new AHA/ASA guidelines update those from 2011 and include more than 30 new recommendations on topics ranging from diet, hypertension, Afib, other cardiac conditions, migraine, and the use of antiplatelet therapies and aspirin.
Addressing the assessment of stroke risk, the new guidelines recognize the AHA/ACC CV Risk Calculator as a reasonable screening tool “to identify patients who could benefit from therapeutic intervention and who may not be treated on the basis of any single risk factor.”
The guidelines further note that this and other risk calculators are useful for both patients and clinicians, “but basing treatment decisions on the results needs to be considered in the context of the overall risk profile of the patient (Class IIa, Level of Evidence B).
Diet, Secondhand Smoke, and Hypertension
The new guidelines add the Mediterranean-style diet to the DASH-style diet as a strategy for lowering stroke risk, and recommend supplementing these diets with nuts (Class IIb, Level of Evidence B).
There are different interpretations of the Mediterranean diet, but all versions emphasize eating vegetables, fruits, whole grains, legumes, fish, and poultry, with very little red meat and full-fat dairy.
The Dash Diet is similar, but tends to be lower in overall fat (no more than 27% of daily calories) and sodium (2,300 mg or less daily).
The guideline committee did not weigh in on the risks or benefits of controversial, but widely followed, carbohydrate-restricted diets.
“We really don’t have enough information at this point to say if this is an acceptable diet with regard to stroke risk,” Meschia said.
The new guidelines recommend increasing efforts to ban public smoking to reduce both stroke and heart attack risk (Class IIa, Level of Evidence B).
Meschia and colleagues noted that hypertension remains the most important, well-documented modifiable risk factor for stroke.
In addition to regular blood pressure screening by physicians, the new recommendations for the first time call for self-measured blood pressure monitoring for hypertensive patients to improve blood pressure control (Class I, Level of Evidence A). A meta-analysis published last year in the journal Annals of Internal Medicine, found that regular self-measurement of blood pressure, with or without additional support, resulted in better blood pressure control.
“Measuring blood pressure every few months in the physician’s office does not give a very good picture of what is happening day to day,” Meschia said. “For patients who are being treated for hypertension, monitoring blood pressure maybe once or twice a week has been shown to be an effective strategy for keeping the numbers where we want them.”
Other new hypertension guidelines include:
- Annual screening for high blood pressure and health-promoting lifestyle modification for patients with prehypertension (systolic BP of 120-139 mmHg or diastolic pressure of 80-89 mmHg (Class I, Level of Evidence A).
- The recognition that successful reduction of blood pressure is more important in reducing stroke risk than the choice of a specific agent, and treatment should be individualized on the basis of other patient characteristics and medication tolerance (Class I, Level of Evidence A).
Afib and Other Cardiac Conditions
Many of the new recommendations address stroke prevention strategies in patients with atrial fibrillation or other cardiac conditions.
New guidelines for the treatment of patients with Afib include:
- Chronic treatment with warfarin at a target INR of 2.0 to 3.0 for patients with valvular Afib, a CHA2DS2-VASc score of 2 or more, and acceptably low risk for hemorrhagic complications.
- For patients with nonvalvular Afib and a CHA2DS2-VASc score of 2 or more, anticoagulant therapy is recommended with either warfarin (INR, 2.0-3.0) (Level of Evidence A), dabigatran (Level of Evidence B), apixaban (Level of Evidence B) and rivaroxaban (Level of Evidence B).
- For patients with nonvalvular Afib and a CHA2DS2-VASc score of 0, it is reasonable to omit antithrombotic therapy (Class IIa, Level of Evidence B).
- For patients with nonvalvular atrial fibrillation, a CHA2DS2-VASc score of 1, and acceptably low risk for hemorrhagic complication, no antithrombotic therapy, anticoagulant therapy, or aspirin therapy may be considered (Class IIb, Level of Evidence C).
Among the new recommendations for the treatment of patients with other cardiac conditions:
- The use of anticoagulation in patients with mitral stenosis and a prior embolic event, even in sinus rhythm (Class I, Level of Evidence B).
- The use of anticoagulation in patients with mitral stenosis and left atrial thrombus (Class I, Level of Evidence B).
- Treatment with warfarin (target INR, 2.0-3.0) and low-dose aspirin after aortic valve replacement with bi-leaflet mechanical or current-generation, single-tilting-disk prostheses in patients with no risk factors (Class I, Level of Evidence B). Warfarin (target INR, 2.5-3.5) and low-dose aspirin are indicated in patients with mechanical aortic valve replacement and risk factors (Class I, Level of Evidence B). Warfarin (target INR, 2.5-3.5) and low-dose aspirin are indicated after mitral valve replacement with any mechanical valve (Class I, Level of Evidence B).
- Surgical intervention is recommended for symptomatic fibroelastomas and for fibroelastomas that are >1 cm or appear mobile, even if asymptomatic (Class I, Level of Evidence C).
- Aspirin is reasonable after aortic or mitral valve replacement with a bioprosthesis (Class IIa, Level of Evidence C).
- It is reasonable to give warfarin to achieve an INR of 2.0-3.0 during the first 3 months after aortic or mitral valve replacement with a bioprosthesis (Class IIa, Level of Evidence C).
- Anticoagulants or antiplatelet agents are reasonable for patients with heart failure who do not have atrial fibrillation or a previous thromboembolic event (Class IIa, Level of Evidence A).
Migraine, Antiplatelet Use Also Addressed
To reduce stroke risk in patients with migraine the guidelines strongly recommend smoking cessation for patients with migraine with aura (Class IIb, Level of Evidence B), and they note that closure of patent foramen ovale is not indicated for preventing stroke.
New recommendations addressing the use of antiplatelet treatments and aspirin include:
- Aspirin might be considered for the prevention of a first stroke in people with chronic kidney disease (i.e., estimated glomerular filtration rate <45 mL·min−1·1.73 m−2) (Class IIb, Level of Evidence C). This recommendation does not apply to severe kidney disease (stage 4 or 5; estimated glomerular filtration rate <30 mL·min−1·1.73 m−2).
- Cilostazol may be reasonable for the prevention of a first stroke in people with peripheral arterial disease (Class IIb,Level of Evidence B).
- As a result of a lack of relevant clinical trials, antiplatelet regimens other than aspirin and cilostazol are not recommended for the prevention of a first stroke (Class III, Level of Evidence C).
Writing group lead author James Meschia disclosed no relevant relationships with industry.