Prevention of stroke may be classified as primary prevention if there is no previous history of stroke or transient ischaemic attack (TIA) and secondary prevention if there has been such an event.

See also other separate articles Primary Prevention of Cardiovascular Disease (CVD) and Secondary Prevention of Cardiovascular Disease.
For tertiary prevention, also see separate article Cerebrovascular Event Rehabilitation.

• Well-documented and modifiable risk factors for stroke include hypertension, exposure to cigarette smoke, diabetes, atrial fibrillation (AF), 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 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 (BP) 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 AF and no contra-indications to anticoagulation.

Primary prevention³

• Use an appropriate cardiovascular risk assessment tool (e.g. Joint British Societies' (JBS2) risk calculator⁴) to assess CVD risk.
  • CVD risk should be calculated as 10-year risk of fatal and non-fatal stroke, including TIA, + 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 (MI), angina and coronary insufficiency (acute coronary syndrome).
• The QRISK2 calculator is gaining acceptance and may be more relevant to UK populations.⁵
• The ETHRISK calculator is more appropriate in British black and minority ethnic groups.⁶

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.
• Dietary advice:
  • Advise eating at least five portions of fruit and vegetables per day.
  • Advise eating at least 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 five 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.⁷
• Antithrombotic treatment:
  • Following acute MI: anticoagulation is appropriate in those who are at increased risk of thromboembolism, including those with a large anterior MI, 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 AF.
• Aspirin:
  • Although use of aspirin is widely accepted for secondary prevention, results in primary prevention are inconclusive, and aspirin is not licensed for this indication.⁸
  • Aspirin produces a 12% proportional reduction in serious vascular events, mainly due to a 20% reduction in non-fatal MI. There was no net effect on stroke and vascular mortality.⁹
  • If low-dose aspirin is used in primary prevention, the balance of risk and benefits should be discussed with the patient.
  • The risk of gastrointestinal bleeding (0.1% per year with aspirin vs. 0.07% per year without) probably outweighs the small benefit in stroke prevention (0.51% aspirin vs. 0.57% control per year) unless the risk is particularly high.
• Lipid-lowering drugs: the National Institute for Health and Clinical Excellence (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 for people with carotid artery stenosis

• 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.¹⁰
  • 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.¹¹
  • 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).¹²
  • Indications include:
    • Symptomatic patients with greater than 70% stenosis: clear benefit was found in the North American Symptomatic Carotid Endarterectomy Trial.¹³
    • Symptomatic patients with 50-69% stenosis: benefit is marginal and appears to be greater for male patients.¹²
    • Asymptomatic patients with greater than 60% stenosis: benefit is significantly less than symptomatic patients with greater than 70% stenosis.¹²
    • Following endarterectomy, recurrent stenosis occurs in 1-20% of cases, and re-operation is necessary in 1-3% of cases.¹⁴
    • Ipsilateral stroke was found to occur in 9% treated with surgery and 26% with medical management after two years of follow-up.¹⁴
  • In general, symptomatic patients with greater than 50% stenosis and healthy, asymptomatic patients with greater than 60% stenosis warrant consideration for carotid endarterectomy.¹²
• Carotid angioplasty and stenting:
  • Stenting with the use of an embolic protection device is a less invasive revascularisation strategy than endarterectomy in carotid artery disease. For patients with severe carotid artery stenosis and co-existing conditions, carotid stenting with the use of an embolic protection device appears to be as safe and as effective as carotid endarterectomy.¹⁵
  • 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.¹²
  • However, one study has shown that angioplasty can be as effective at preventing stroke over three years as carotid endarterectomy, with similar major risks.¹⁶
  • This procedure is currently indicated in selected cases such as restenosis and stenoses located both proximally and distally to the carotid bifurcation.¹⁷

Secondary prevention of stroke and transient ischaemic attacks¹¹

• All patients should have an individualised strategy for stroke prevention that should be implemented within a maximum of seven 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.
• BP: all patients who have a high BP persisting for over two weeks should be treated. The British Hypertension Society guidelines are:⁷
  • In nondiabetic people with hypertension, the optimal BP treatment goals are systolic BP less than 140 mm Hg and diastolic BP less than 85 mm Hg.
  • For patients with diabetes mellitus and high BP, the optimal goals of control are 130/80 mm Hg.
  • Further reduction of BP should be undertaken using a thiazide diuretic (e.g. bendroflumethiazide or indapamide) or an angiotensin-converting enzyme (ACE) inhibitor (e.g. perindopril or ramipril) or preferably a combination of both, unless there are contra-indications.
• Antithrombotic treatment:
  • If there is a history of persistent or paroxysmal AF in a non-haemorrhagic stroke, consider anticoagulation first-line:
    • Anticoagulation should be started in every patient with persistent or paroxysmal AF (valvular or non-valvular) unless contra-indicated.⁴
    • Anticoagulants should not be used for patients without persistent or paroxysmal AF unless there is a major source of cardiac embolism.
    • Anticoagulation is indicated for other cardiovascular risk factors for thromboembolism, e.g. prosthetic valves.¹⁸
    • 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.
  • Patients with TIAs not being anticoagulated should be on modified-release dipyridamole in combination with aspirin (modified-release dipyridamole alone if aspirin not tolerated).¹⁹
  • Patients with ischaemic stroke (not due to AF) should be on clopidogrel (only use modified-release dipyridamole in combination with aspirin if clopidogrel not tolerated). Clopidogrel is also the preferred treatment option in patients with peripheral arterial disease or multivascular disease.¹⁹
  • For patients post-MI, an option including aspirin is preferred (use clopidogrel only, if aspirin not tolerated).
• Anti-lipid agents:
  • Treatment with a statin should be given to all patients with ischaemic stroke or TIA unless contra-indicated.³

Document references

1. Goldstein LB, Adams R, Alberts MJ, et al; Primary prevention of ischemic stroke: a guideline from the American Heart Association/American Stroke Association Stroke Council: cosponsored by the Atherosclerotic Peripheral Vascular Disease Interdisciplinary Working Group; Cardiovascular Nursing Council; Clinical Cardiology Council; Nutrition, Physical Activity, and Metabolism Council; and the Quality of Care and Outcomes Research Interdisciplinary Working Group. Circulation. 2006 Jun 20;113(24):e873-923. [abstract]
2. Sudlow C; Preventing further vascular events after a stroke or transient ischaemic attack: an update on medical management. Pract Neurol. 2008 Jun;8(3):141-57. [abstract]
3. Lipid modification, NICE Clinical Guideline (May 2008); (Cardiovascular risk assessment and the modification of blood lipids for the primary and secondary prevention of cardiovascular disease.) amended May 2010
4. No authors listed, JBS 2: Joint British Societies' guidelines on prevention of cardiovascular disease in clinical practice. Heart. 2005 Dec;91 Suppl 5:v1-52.
5. QRISK® Cardiovascular Risk Assessment Calculator
6. ETHRISK® - Ethnic Group CHD Risk Calculator (modified Framingham); A modified Framingham CHD and CVD risk calculator for British black and minority ethnic groups
7. Guidelines for the Management of Hypertension, British Hypertension Society (2006)
8. Aspirin: not licensed for primary prevention of thrombotic vascular disease, Medicines and Healthcare products Regulatory Agency (MHRA) Drug Safety Update 3(3), 10-11. (2009)
9. Baigent C, Blackwell L, Collins R, et al; Aspirin in the primary and secondary prevention of vascular disease: Lancet. 2009 May 30;373(9678):1849-60. [abstract]
10. Cina CS, Clase CM, Haynes RB; Carotid endarterectomy for symptomatic carotid stenosis. Cochrane Database Syst Rev. 2000;(2):CD001081. [abstract]
11. Stroke: The diagnosis and acute management of stroke and transient ischaemic attacks, NICE Clinical Guideline (July 2008)
12. Chambers BR, Donnan GA; Carotid endarterectomy for asymptomatic carotid stenosis. Cochrane Database Syst Rev. 2005 Oct 19;(4):CD001923. [abstract]
13. Barnett HJ, Meldrum HE, Eliasziw M; The appropriate use of carotid endarterectomy. CMAJ. 2002 Apr 30;166(9):1169-79. [abstract]
14. Barnett HJ, Taylor DW, Eliasziw M, et al; Benefit of carotid endarterectomy in patients with symptomatic moderate or severe stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators. N Engl J Med. 1998 Nov 12;339(20):1415-25. [abstract]
15. Yadav JS, Wholey MH, Kuntz RE, et al; Protected carotid-artery stenting versus endarterectomy in high-risk patients. N Engl J Med. 2004 Oct 7;351(15):1493-501. [abstract]
16. McCabe DJ, Pereira AC, Clifton A, et al; Restenosis after carotid angioplasty, stenting, or endarterectomy in the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS). Stroke. 2005 Feb;36(2):281-6. Epub 2005 Jan 13. [abstract]
17. De Fabritiis A, Conti E, Coccheri S; Management of patients with carotid stenosis. Pathophysiol Haemost Thromb. 2002 Sep-Dec;32(5-6):381-5. [abstract]
18. Sacco RL, Adams R, Albers G, et al; Guidelines for prevention of stroke in patients with ischemic stroke or transient ischemic attack: a statement for healthcare professionals from the American Heart Association/American Stroke Association Council on Stroke: co-sponsored by the Council on Cardiovascular Radiology and Intervention: the American Academy of Neurology affirms the value of this guideline. Stroke. 2006 Feb;37(2):577-617. [abstract]
19. Vascular disease - clopidogrel and dipyridamole, NICE Technology Appraisal Guideline (December 2010); Clopidogrel and modified-release dipyridamole for the prevention of occlusive vascular events

Internet and further reading

• Management of patients with stroke or TIA: assessment, investigation, immediate management and secondary prevention, Scottish Intercollegiate Guidelines Network (SIGN), December 2008
• National Service Framework for Older People. Chapter 5. Dept of Health (2001)
• The Stroke Association
• Blood Pressure Association Patient Website
• American Stroke Association; Resources for Health Professionals
• Food and diet, Food Standards Agency
• 5 (fruit and vegetables) a day, NHS

Acknowledgements