Stroke Prevention

Prevention of stroke may be classified as primary prevention if there is no previous history of stroke or transient ischaemic attack and secondary prevention if there has been such an event.
See also other articles Primary Prevention of Cardiovascular Disease (CVD) and Secondary Prevention of Ischaemic Heart Disease.
For tertiary prevention, also see the article Cerebrovascular Event Rehabilitation.

• Well-documented and modifiable risk factors for stroke include hypertension, exposure to cigarette smoke, diabetes, atrial fibrillation, dyslipidaemia, carotid artery stenosis, sickle cell disease, postmenopausal hormone therapy, poor diet, physical inactivity, and obesity especially truncal obesity.¹
• Less well-documented or potentially modifiable risk factors include the metabolic syndrome, alcohol abuse, drug abuse, oral contraceptive use, obstructive sleep apnoea, migraine headaches, hyperhomocysteinaemia, elevated lipoprotein(a), elevated lipoprotein-associated phospholipase, and hypercoagulability.¹
• After a stroke or transient ischaemic attack (TIA), there is a high risk of stroke and of other serious vascular events. Medical treatments with clear evidence of benefit include:²
  • Lowering blood pressure after all types of stroke or TIA
  • Lowering blood cholesterol with a statin after ischaemic stroke or TIA
  • Antiplatelet treatment after ischaemic stroke or TIA
  • Warfarin instead of antiplatelet treatment in patients with ischaemic stroke or TIA who have atrial fibrillation and no contraindications to anticoagulation

• NICE recommends that the Framingham 1991 10-year risk equations, as used in the Joint British Societies (JBS2) risk calculator,⁴ should be used to assess CVD risk.
• The JBS2 risk calculator (which is based on the Framingham equations) is not the only risk calculator in use and tends to be less accurate for certain population groups, e.g. women, ethnic minority groups, social deprivation.
• CVD risk should be calculated as 10-year risk of fatal and non-fatal stroke, including transient ischaemic attack, + 10-year risk of coronary heart disease (CHD).
• CHD risk includes the risks of death from CHD, and non-fatal CHD, including silent myocardial infarction, angina and coronary insufficiency (acute coronary syndrome).

Lifestyle factors³

• Advise people to eat a diet in which:
  • Total fat intake is 30% or less of total energy intake.
  • Saturated fats are 10% or less of total energy intake.
  • Dietary cholesterol is less than 300 mg/day.
  • Saturated fats are replaced by monounsaturated and polyunsaturated fats.
• Advise eating at least:
  • Five portions of fruit and vegetables per day.
  • Two portions of fish per week, including a portion of oily fish.
  • Advise pregnant women to limit their intake of oily fish to two portions a week.
  • Do not routinely recommend omega-3 fatty acid supplements or plant sterols and stanols for primary prevention.
• Physical activity:
  • Advise people to take 30 minutes of at least moderate intensity exercise a day at least 5 days a week.
  • Encourage people who cannot manage this to exercise at their maximum safe capacity.
  • Recommend exercise that can be incorporated into everyday life, such as brisk walking, using stairs and cycling.
  • Tell people that they can exercise in bouts of 10 minutes or more throughout the day.
  • Take into account the person’s needs, preferences and circumstances.
  • Agree goals and provide written information about the benefits of activity and local opportunities to be active.
• Weight management:
  • Offer people who are overweight or obese advice and support to work towards achieving and maintaining a healthy weight.
• Alcohol consumption:
  • Advise men to limit their alcohol intake to 3–4 units a day.
  • Advise women to limit their alcohol intake to 2–3 units a day.
  • Advise everyone to avoid binge drinking.
• Smoking cessation:
  • Advise all people who smoke to stop.
  • If people want to stop:
  • Offer support and advice.
  • In addition, provide medication to help with smoking cessation when indicated.

Drug treatment

• Hypertension:
  • Screen for hypertension and treat appropriately according to British Hypertension Society guidelines.⁵
• Antithrombotic treatment:
  • Following acute myocardial infarction; anticoagulation is appropriate in those who are at increased risk of thromboembolism including those with a large anterior myocardial infarction, left ventricular aneurysm or thrombus, paroxysmal tachyarrhythmias, chronic heart failure or a history of thromboembolic events.⁴
  • Anticoagulation is indicated for other cardiovascular risk factors for thromboembolism, e.g. prosthetic valves, rheumatic heart disease and atrial fibrillation.
• Aspirin:
  • Although use of aspirin is widely accepted for secondary prevention, results in primary prevention are inconclusive.
  • Low dose aspirin should be considered for people whose 10-year risk of CVD is calculated as being 20% or greater.⁶
• Lipid lowering drugs: NICE recommends statin therapy as part of the management strategy for the primary prevention of CVD for adults who have a 20% or greater 10-year risk of developing CVD.³

• Carotid endarterectomy:
  • Reduces the risk of disabling stroke or death by 48% in a person with severe symptomatic carotid stenosis (more than 70% stenosis) who has had a TIA.⁷
  • In trials of carotid endarterectomy in people with TIA the perioperative risk of disabling stroke or death is less than 5%.
  • Carotid endarterectomy should be performed as soon as the patient is fit for surgery, preferably within two weeks of a TIA.⁸
  • Despite a 3% perioperative stroke or death rate, carotid endarterectomy for asymptomatic carotid stenosis reduces the risk of any stroke by approximately 30% over three years. However, the absolute risk reduction is small (1% per annum over the first few years of follow up in recent trials).⁹
  • Indications include:
    • Symptomatic patients with greater than 70% stenosis: clear benefit was found in the North American Symptomatic Carotid Endarterectomy Trial.¹⁰
    • Symptomatic patients with 50-69% stenosis: benefit is marginal and appears to be greater for male patients.⁹
    • Asymptomatic patients with greater than 60% stenosis: benefit is significantly less than symptomatic patients with greater than 70% stenosis.⁹
    • Following endarterectomy, recurrent stenosis occurs in 1-20% of cases, and reoperation is necessary in 1-3% of cases.¹¹
    • Ipsilateral stroke was found to occur in 9% treated with surgery and 26% with medical management after 2 years of follow up.¹¹
  • In general, symptomatic patients with greater than 50% stenosis and healthy, asymptomatic patients with greater than 60% stenosis warrant consideration for carotid endarterectomy.⁹
• Carotid angioplasty and stenting:
  • Stenting with the use of an emboli-protection device is a less invasive revascularisation strategy than endarterectomy in carotid-artery disease. For patients with severe carotid artery stenosis and coexisting conditions, carotid stenting with the use of an emboli-protection device appears to be as safe and as effective as carotid endarterectomy.¹²
  • Endovascular treatment and carotid endarterectomy appear to have similar early risks of death or stroke and similar long term benefits in the treatment of carotid artery stenosis.⁹
  • However one study has shown that angioplasty can be as effective at preventing stroke over 3 years as carotid endarterectomy, with similar major risks.¹³
  • This procedure is currently indicated in selected cases such as restenosis and stenoses located both proximally and distally to the carotid bifurcation.¹⁴

• All patients should have an individualised strategy for stroke prevention that should be implemented within a maximum of 7 days of acute stroke or TIA.
• All patients should be given appropriate advice on lifestyle factors as described for primary prevention, including smoking cessation, physical activity, diet, weight control and avoiding excess alcohol.
• All patients should receive regular review and treatment of risk factors for vascular disease for the rest of their lives after a stroke with inclusion on a stroke register and a minimum of annual follow-up.
• Blood pressure; all patients who have a high blood pressure persisting for over two weeks should be treated. The British Hypertension Society guidelines are:⁵
  • In non-diabetic people with hypertension, the optimal blood pressure treatment goals are systolic blood pressure less than 140 mmHg and diastolic blood pressure less than 85 mmHg.
  • For patients with diabetes mellitus and high blood pressure, the optimal goals of control are 130/80.
  • Further reduction of blood pressure should be undertaken using a thiazide diuretic (e.g. bendroflumethiazide or indapamide) or an ACE inhibitor (e.g. perindopril or ramipril) or preferably a combination of both, unless there are contraindications.
• Anti-thrombotic treatment:
  • All patients with ischaemic stroke or TIA who are not on anticoagulation should be taking an antiplatelet agent, i.e. low-dose aspirin (e.g. 75 mg).
    Where patients are intolerant of aspirin, an alternative antiplatelet agent (e.g.clopidogrel 75 mg daily and/or dipyridamole MR 200 mg twice daily) should be used.
    Patients with an occlusive stroke (not due to atrial fibrillation) should receive aspirin and dipyridamole for two years before reverting to aspirin alone.¹⁵
• Anticoagulation:
  • Should be started in every patient with persistent or paroxysmal atrial fibrillation (valvular or non-valvular) unless contraindicated.⁴
  • Anticoagulants should not be used for patients in sinus rhythm unless there is a major source of cardiac embolism.
  • Anticoagulation is indicated for other cardiovascular risk factors for thromboembolism, e.g. prosthetic valves.¹⁶
  • Anticoagulants should not be started until brain imaging has excluded haemorrhage, and usually not until 14 days have passed from the onset of an ischaemic stroke.
• Anti-lipid agents:
  • Treatment with a statin should be given to all patients with ischaemic stroke or TIA unless contraindicated.³