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11.05.2006, 20:19
May 4, 2006 — The American Heart Association (AHA)/American Stroke Association (ASA) have issued a 2006 update of their 2001 guidelines on primary stroke prevention. These guidelines are published in the May 4 Rapid Access issue of Stroke: Journal of the American Heart Association.

The new report includes several recommendations regarding the identification and modification of stroke risk factors. The writing group, led by Larry B. Goldstein, MD, with the Duke University Medical Center, in Durham, NC, reviewed several lines of evidence and conducted a systematic literature review of new reports from 2001 to January 2005.

While the death rate from stroke has declined by about 18.5% since 1993, the annual incidence of stroke, which afflicts about 700 000 people a year in the United States, has declined by less than 1%, according to information in an AHA written release.

Risk factors and markers for a first stroke were classified according to their potential for modification (nonmodifiable, modifiable, or potentially modifiable) and strength of evidence (well-documented or less well-documented).

According to the report, nonmodifiable risk factors include age, sex, race/ethnicity, and family history. As was previously known, stroke is more likely to affect the elderly, men, African Americans, and people with a family history of stroke.

In addition, data published since 2001 suggest that low birth weight is also a potential nonmodifiable risk factor; adults born with a birth weight of 2500 g or less are at more than twice the risk for stroke compared with those with a birth weight of less than 4000 g, according to the report, although the reason for this relationship remains unclear.

Modifiable risk factors cited by the report include high blood pressure, smoking and passive smoking, lack of physical activity; and inadequate treatment of atrial fibrillation, carotid artery disease, and heart failure.

The guidelines recommend the use of a risk assessment tool, such as the Framingham Stroke Profile, to assess stroke risk. In addition, the report suggests that patients with rare genetic causes of stroke should be referred for genetic counseling, and high-risk patients with diabetes should be treated with statins.

In addition, the report recommends that transcranial Doppler ultrasound screenings should be conducted in children with sickle cell anemia at age 2 years, and transfusion therapy should be considered for those found to be at high risk for stroke. Adults with sickle cell anemia also should be assessed for known stroke risk factors, the report suggests.

Sleep apnea newly was cited as a potentially modifiable risk factor for stroke. Other less well-documented and potentially modifiable risk factors mentioned include the metabolic syndrome, alcohol use, illicit drugs, and use of oral contraceptives (OCs) in female smokers.

"We know that treating sleep apnea is associated with a reduction of blood pressure," Dr Goldstein noted in a written release. "And although we don't have direct evidence that treating sleep apnea will reduce stroke risk, the feeling is that it will. But that is not yet supported by randomized trials."

The guidelines also listed various other emerging risk factors for stroke, including inflammation, infection, and migraine.

Nutritional factors associated with stroke suggested that higher potassium and lower sodium may benefit patients perhaps "through mechanisms that are independent of blood pressure." In addition, recommendations to "meet current guidelines for daily intake of folate (400 µg/d), B6 (1.7 mg/d), and B12 (2.4 µg/d) by consumption of vegetables, fruits, legumes, meats, fish, and fortified grains and cereals (for nonpregnant, nonlactating individuals) may be useful in reducing the risk of stroke," the report indicates.

With regard to the use of low-dose aspirin, women whose risk is sufficiently high for the benefits to outweigh the risks may benefit from this approach. However, the evidence is not strong enough to recommend aspirin in men at high risk for stroke, according to the guidelines.

Other recommendations included the use of prophylactic carotid endarterectomy surgery by a surgeon with a low complication rate for asymptomatic patients with severe carotid blockage and avoidance of using hormone therapy (with estrogen, with or without progestin) for the primary prevention of stroke.

Stroke. Posted online May 4, 2006.

11.05.2006, 20:19
Learning Objectives for This Educational Activity

Upon completion of this activity, participants will be able to:

Define nonmodifiable and modifiable stroke risk factors.
Describe updates of the AHA/ ASA 2006 guidelines for stroke prevention.

Clinical Context

More than 700 000 cases of incident stroke occur yearly in the United States, resulting in more than 160 000 deaths, with 4.8 million stroke survivors today. The 2006 indirect cost of stroke is estimated at US $57.9 billion. Stroke is the third leading cause of death, and the age-adjusted hospitalization rate increased from 18.6% to 38.6% between 1988 and 1997, with 20% of survivors needing institutionalized care for 3 months and 15% to 30% being permanently disabled. The stroke death rate decreased by only 0.7% between 1993 and 2003. Seventy percent of strokes are first events, and primary prevention is particularly important.

This guideline approved by the AHA Science Advisory and Coordinating Committee is an overview of the evidence on potential stroke risk factors and factors amenable to primary prevention strategies. It is a complete revision of the last statement published by Goldstein and colleagues in Stroke in January 2001. The authors used a combination of systematic literature reviews, published guidelines, personal files, and expert opinion to summarize current evidence for modifiable and nonmodifiable stroke risk factors and for modifiable risk factors, separated well-documented and potentially modifiable factors.

Study Highlights

Nonmodifiable Risk Factors
The risk for stroke doubles with each successive decade after 55 years.
Men have higher age-specific stroke incidence rates than women, except for those aged 35 to 44 years and older than 85 years, groups in which women have higher rates.
OC use and pregnancy contribute to stroke risk in women.
The odds of stroke are more than doubled in individuals older than 50 years who had low birth weights of less than 2000 g vs those with birth weights above 4000 g.
African Americans and some Hispanic Americans have higher stroke rates and stroke mortality vs European Americans.
Familial history of stroke confers increased risk.

Modifiable Risk Factors (Well-documented)
The presence of atherosclerotic disease overall confers increased stroke risk.
Hypertension remains undertreated. The Joint National Commission on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure 7 guidelines recommends regular screening every 2 years with appropriate management.
Ischemic stroke risk doubles for cigarette smokers, and hemorrhagic stroke risk increases 2 to 4 times vs nonsmokers.
There is a synergistic effect of smoking on stroke risk in women using OCs.
Passive cigarette smoke confers a doubling of risk for stroke approaching that of active smoking, and an "exposure threshold" rather than a dose-response relationship is observed.
Smoking cessation is associated with a rapid risk reduction approaching that of nonsmokers.
Antihypertensive treatment of people with diabetes reduces stroke risk by more than 20%.
Addition of a statin for diabetic patients at high risk reduces stroke risk by 24% and in diabetic patients with 1 additional risk factor by 48%.
The use of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in diabetic patients is endorsed.
All patients with mechanical heart valves require anticoagulation. The rate of thromboembolism is reduced from 4.4 to 2.2 (with antiplatelet therapy) and 1.0 per 100 patient-years with warfarin.
Atrial fibrillation confers a 3- to 4-fold increase in stroke risk. Aspirin use reduces risk by 20%, whereas warfarin use reduces risk by 60%.
Lipid-modifying medications can reduce stroke risk in patients with coronary disease.
Patients with asymptomatic carotid stenosis should be screened for other treatable causes of stroke; aspirin should be used; prophylactic endarterectomy should be used for those with high-grade stenosis and performed by surgeons with less than 3% morbidity/mortality rates.
Transcranial Doppler ultrasound should be used to screen children with sickle cell disease at high risk for stroke starting at 2 years of age, and blood transfusions reduce stroke risk from 10% per year to 1% per year.
Adults with sickle cell anemia should be evaluated for known stroke risk.
Hormone replacement therapy is not recommended for stroke risk reduction in women.
Sodium intake should be less than 2.3 g/day, and potassium intake more than 4.7 g/day; the Dietary Approaches to Stop Hypertension diet is recommended.

Modifiable Risk Factors (Potential)
Individual components of the metabolic syndrome should be managed.
Men should have less than 2 and women less than 1 alcohol drink daily.
Sleep apnea is a risk factor, and bed partners of patients with obesity should be questioned about the patient's snoring, and potential referral to a sleep specialist should be considered.
The US Preventive Services Task Force recommends 75 mg of aspirin daily for those with 5-year stroke risk of more than 3%, whereas the AHA recommends treatment of those with 10-year stroke risk of more than 10%.

Pearls for Practice
Primary stroke prevention may be achieved by management of well-documented and potentially modifiable risk factors in patients.
The updated AHA/ASA guidelines include strategies for primary stroke prevention for those with sickle cell disease, carotid stenosis, sleep apnea, and passive smoking exposure and recommends statins for patients with diabetes.

2006 Medscape.

23.08.2007, 01:13
Кратенький апдейт по теме: Prevention of Recurrent Ischemic Stroke

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