What are the AHA/ASA guidelines on primary stroke prevention?

Updated: Jan 10, 2016
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Answer

In October 2014, the American Heart Association and American Stroke Association (AHA/ASA) released an update of their 2011 Guidelines for the Primary Prevention of Stroke. [3] These guidelines were endorsed and/or affirmed by the following organizations:

  • American Association of Neurological Surgeons
  • Congress of Neurological Surgeons
  • Preventative Cardiovascular Nurses Association
  • American Academy of Neurology

The guidelines provide an overview of established and emerging risk factors for stroke and outline risk assessment strategies. The influence of both modifiable and unmodifiable risk factors are discussed, to permit estimation of risk for a first stroke for an individual patient. In general, the use of the AHA/ACC CV Risk Calculator [4] is reasonable to alert clinicians and patients to possible risk. When making treatment decisions, however, clinicians need to consider the results in the context of the patient’s overall risk profile.

With evidence that 10 modifiable risk factors accounted for 90% of the risk for stroke, [5] the guidelines stress the importance of identifying and providing effective interventions to stroke-prone individuals. Both established and emerging modifiable risk factors and evidence-based recommendations for management are summarized in Table 1, below. [3]

Table 1. Recommendations for Stroke Risk Reduction   (Open Table in a new window)

Established Risk Factor

Recommendation

Category

Hypertension

Regular blood pressure (BP) screening; appropriate hypertension treatment.

Prehypertension (systolic BP of 120-139 mm Hg or diastolic BP of 80-89 mm Hg): Perform annual BP screening and lifestyle modifications

Hypertension: Treat to target < 140/90 mm Hg; BP reduction is more important than choice of agent in lowering stroke risk; individualize therapy. Home self-monitoring of blood pressure in hypertensive patients

Class I

Physical Inactivity

Healthy adults: moderate- to vigorous-intensity aerobic activity at least 40 minutes per day, 3-4 days per week

Class I

Dyslipidemia

Lifestyle interventions

High 10-year cardiovascular risk: Initiate statin therapy

Class I

Low high-density lipoprotein cholesterol or high lipoprotein (Lp)(a): Consider niacin, although efficacy in stroke prevention not established

Hypertriglyceridemia: Consider fibric acid derivatives, although efficacy in stroke prevention not established

If statin-intolerant, consider other lipid-lowering therapies, although efficacy in stroke prevention not established

Class IIb

Diet and Nutrition

Reduced sodium and increased potassium intake; DASH-style diet rich in fruits and vegetables

Class I

Consider Mediterranean diet supplemented with nuts

Class IIa

Obesity

Weight reduction in overweight and obese individuals

Class I

Diabetes Mellitus

Type 1 or type 2 diabetes: Control BP, per AHA/ACC/CDC Advisory to target < 140/90 mm Hg; Treat adults with diabetes with a statin, especially in case of additional risk factors

Class I

Usefulness of aspirin for primary stroke prevention in those with diabetes but a low 10-year risk for cardiovascular disease is unclear

Class IIb

Add-on fibrate in those with diabetes is not useful in reducing stroke risk

Class III

Smoking

Counseling plus drug therapy for smokers; maintain abstinence in those who have never smoked

Class I

Community-wide or statewide bans on smoking in public spaces are reasonable

Class IIa

Atrial Fibrillation

Valvular AF and high stroke risk (CHA2DS2-VASc score ≥ 2): Initiate long-term warfarin therapy; target international normalized ratio (INR), 2.0-3.0

Nonvalvular AF, CHA2DS2-VASc score ≥2, and low risk for hemorrhagic complications: Individualize care and consider warfarin, dabigatran, apixaban, or rivaroxaban

Class I

AF screening in the primary care setting in those older than 65 years

Nonvalvular AF and CHA2DS2-VASc score of 0: reasonable to omit antithrombotic therapy

Class IIa

Nonvalvular AF, CHA2DS2-VASc score 1, and low risk for hemorrhagic complications: No antithrombotic therapy, anticoagulant therapy, or aspirin therapy can be considered; selection of antithrombotic agent should be individualized on the basis of patient risk factors

High-risk patients with AF who are unsuitable for anticoagulation: Consider left atrial appendage closure, if performed at a center with a low complication rate

Class IIb

Other Cardiac Conditions

Mitral stenosis and prior embolic event: anticoagulation

Mitral stenosis and left atrial thrombus: anticoagulation

Aortic valve replacement with bileaflet mechanical or current-generation, single-tilting-disk prostheses plus no risk factors: warfarin (INR 2.0-3.0) and low-dose aspirin

Mechanical aortic valve replacement and risk factors(ie, AF, previous thromboembolism, left ventricular dysfunction, and hypercoagulable state): warfarin (INR 2.5-3.5) and low-dose aspirin

Mitral valve replacement with any mechanical valve: warfarin (INR 2.5-3.5) and low-dose aspirin

Atrial myxomas: surgical excision

Symptomatic fibroelastomas and those >1 cm or that appear mobile: surgical intervention

Class I

Aortic or mitral valve replacement with a bioprosthesis: aspirin and warfarin (INR 2.0-3.0) are reasonable

Heart failure but no AF or previous thromboembolic event:  anticoagulants or antiplatelets are reasonable

ST-segment elevation myocardial infarction (STEMI) and asymptomatic left ventricular mural thrombi:  vitamin K antagonist therapy is reasonable

Class IIa

Asymptomatic patients with severe mitral stenosis and left atrial dimension ≥ 55 mm by echo:  consider anticoagulation

Severe mitral stenosis, an enlarged left atrium, and spontaneous contrast on echo: consider anticoagulation

STEMI and anterior apical akinesis or dyskinesis: consider anticoagulation

Class IIb

Patent foramen ovale (PFO): Antithrombotic therapy and catheter-based closure are not recommended for primary stroke prevention

Class III

Carotid Artery Stenosis

Asymptomatic carotid stenosis: statin plus daily aspirin; screen for and manage other stroke risk factors

Carotid endarterectomy (CEA): peri- and postoperative aspirin, unless contraindicated

Class I

Asymptomatic with >70% stenosis:  consider CEA if perioperative risk for stroke, MI, and death is low (< 3%)

>50% stenosis: repeat duplex ultrasonography annually to assess progression, regression, and treatment response

Class IIa

Consider prophylactic stenting in highly selected patients with asymptomatic stenosis (≥60% by angiography or ≥70% by validated Doppler ultrasonography)

Asymptomatic, but high risk for CEA or carotid artery stenting complications: effectiveness of revascularization vs medical therapy is not well established

Class IIb

Screening low-risk populations for asymptomatic stenosis is not recommended

Class III

Sickle Cell Disease

Children with sickle cell disease (SCD): transcranial Doppler (TCD) screening started at age 2 years, then annually through age 16 years

Children with increased stroke risk: transfusion therapy targeting hemoglobin S < 30%

Class I

Screen younger children and those with borderline abnormal TCD flow velocities more frequently; continued transfusion is probably reasonable, even after TCD velocities revert to normal

Class IIa

High stroke risk and unable or unwilling to be treated with periodic transfusions:  consider hydroxyurea or bone marrow transplantation

Class IIb

MRI and magnetic resonance angiography criteria for selecting patients for primary stroke prevention with transfusion are not established; therefore, they are not recommended in place of TCD for this purpose

Class III

Emerging Risk Factor

Migraine

Women with migraine plus aura: smoking cessation

Class I

Women with active migraines plus aura: consider alternatives to oral contraceptives

Consider treatments that reduce migraine frequency

Class IIb

PFO closure not indicated for stroke prevention

Class III

Alcohol Consumption

Heavy drinkers:  reduce or stop consumption

Class I

Persons who continue drinking: ≤2 drinks/day for men; ≤1 drink/day for nonpregnant women

Class IIb

Drug Abuse

Referral to therapeutic/rehabilitation program

Class IIa

Sleep-Disordered Breathing

Although no randomized trial data exist demonstrating effectiveness  for primary stroke prevention, screening and treatment of sleep apnea may be considered

Class IIb

Hyperhomocysteinemia

Although effectiveness has not been established, B-complex vitamins may be considered

Class IIb

Elevated Lp(a)

Some genetic and epidemiologic studies suggest that Lp(a) is a risk factor for cardiovascular disease, including stroke and niacin may be considered

Class IIb

Hypercoagulability

Usefulness of genetic screening to detect inherited hypercoagulability for stroke prevention is not well established

Asymptomatic patients with hereditary or acquired thrombophilia: Usefulness of specific treatments for stroke prevention is not well established

Class IIb

Persistently antiphospholipid antibody–positive patients: Low-dose aspirin is not indicated

Class III

Inflammation and Infection

Chronic inflammatory conditions (ie, rheumatoid arthritis and systemic lupus erythematosus): consider these patients to have increased stroke risk; enhanced risk factor measurement and control.

Class I

Annual flu vaccine can be useful

Class IIa

Measurement of inflammatory markers such as hs-CRP or lipoprotein-associated phospholipase A2 in patients without CVD may be considered to identify patients who may be at increased risk of stroke, although their usefulness in routine clinical practice is not well established

High-sensitivity C-reactive protein (hs-CRP) >2 mg/dL: consider statin therapy

Class IIb

Antibiotics for chronic infections as means to prevent stroke are not recommended

Class III

In addition, the guidelines acknowledge that the individual components of the metabolic syndrome can increase stroke risk and should be managed appropriately. Medications and lifestyle changes should be used to treat hypertension and hyperlipidemia and provide glycemic control, as they would for persons with individual risk factors. [3]

With regard to antiplatelet agents and aspirin, the guidelines note that although some evidence supports the use of aspirin in the primary prevention of stroke in women, the benefits are small; if opting for aspirin therapy, the potential risks of stroke should outweigh the risks of aspirin use. [3]

Diagnosis and management of stroke caused by cerebral venous thrombosis (CVT) was the subject of a 2011 AHA/ASA statement. Primary prevention of CVT has not been the focus of randomized clinical trials, but the AHA/ASA statement suggests that primary prevention strategies for venous thromboembolism in general may have some efficacy with respect to CVT. [6]


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