Can you take measures to prevent recurrent stroke?

The author of this article assessed treatments for secondary stroke prevention.

Survivors of stroke and transient ischemic attacks (dysfunction of the nervous system from temporary loss of blood flow) are at risk of a recurrent stroke, which is often more severe and disabling than the initial event. Recurrent strokes constitute 25-30% of preventable strokes.

The author of this article describes the prognosis (outlook) and predictors of early and long-term recurrent stroke with strategies to prevent both these types of stroke.

The risk of a recurrent stroke is highest early after an ischemic stroke or transient ischemic attack – about 1% at 6 hours, 2% at 12 hours, 3% at 2 days, 5% at 7 days, and 10% at 14 days. Clinical features such as sudden-onset unilateral (one-sided) weakness and speech disturbance lasting for longer than 10 minutes can predict a high risk of stroke soon after transient ischemic attack. Effective strategies to prevent early recurrent ischemic stroke include assessment and management in an acute specialist unit (immediate access to treatment), immediate antiplatelet therapy (to block the formation of blood clots), and early carotid revascularization (restoration of blood flow through the carotid artery that supplies blood to the head and neck).  

As a single antiplatelet therapy, aspirin 160–300 mg daily, started within 48 hours of onset of ischemic stroke in 40,000 patients, and continued for 2–4 weeks, reduced the odds of recurrent ischemic stroke by 23%. Therapy increased the odds of symptomatic intracranial haemorrhage (bleeding within the skull) by 22%, and reduced the odds of any recurrent stroke by 12%. Another study estimated that dual (two antiplatelet drugs) therapy significantly reduced the risk of early recurrent stroke by 31% compared to single antiplatelet therapy

Another study compared outcomes in carotid endarterectomy (removal of the inner lining of the carotid artery) compared to carotid artery stenting (insertion of a slender, metal mesh tube to hold the artery open) in 7,572 patients showing symptoms of carotid stenosis (narrowing of the carotid artery).  Both treatments are used to restore blood flow to the brain through the carotid artery. Compared with endarterectomy, carotid artery stenting was associated with 63% reduction in the risk of access site hematoma (solid swelling of clotted blood at the site of surgery), 92% reduced risk of cranial (brain) nerve injury and 56% reduced risk of heart attack. However, compared to endarterectomy, carotid artery stenting was associated with an 81% increased risk of stroke during the procedure and 72% increase in the risk of stroke or death.

Speciality transient ischemic attack units, which combine emergency assessment with antiplatelet therapy, lowering of blood pressure, and carotid endarterectomy as appropriate, might reduce the risk of early recurrent stroke by up to 80% compared with appointment-based clinical assessments and treatment initiated by the family doctor.

The risk of recurrent stroke in survivors of stroke is about 11.1% at 1 year, 26.4% at 5 years, and 39.2% at 10 years.  In young adults (18–50 years of age) who have had a stroke, the 20-year risk of recurrent ischemic stroke is about 19%. Predictors of a raised risk of recurrent stroke in the long term include older age, high blood pressure, diabetes, smoking, previous symptomatic vascular disease (stroke, heart attack, or disease of the arteries that supply the arms and legs) and unstable vascular disease (several recurrent recent ischemic events of the brain). Effective strategies to prevent recurrent ischemic stroke in the long term include antiplatelet therapy, risk factor control, and early carotid revascularization.

Clopidogrel (Plavix) reduces the risk of stroke and other major vascular events by about 9% compared with aspirin. Clopidogrel is 31% less likely to cause gastrointestinal bleeding compared to 325 mg aspirin daily, with an absolute annual decrease of 0.12%.

Sustained lowering of blood pressure by 5.1 mmHg systolic (pressure when the heart is contracting) and 2.5 mmHg diastolic (pressure when the heart is relaxing) pressure reduces recurrent stroke by about a fifth. Larger reductions in blood pressure—by 10 mmHg systolic and 5 mmHg diastolic pressure—are associated with a 34% reduction in the risk of recurrent stroke. Blood pressure can be reduced by lifestyle interventions, such as regular physical exercise for 30 minutes daily, alcohol reduction, a low-salt diet, and increased potassium intake, and by medication with any class of antihypertensive drugs (drugs to combat high blood pressure).

Lowering of low-density lipoprotein cholesterol (bad cholesterol) concentration by about 1 mmol/L with statins reduces the risk of recurrent stroke by about 12% and all stroke by about 21%. Statins are cholesterol -reducing drugs including rosuvastatin (Crestor) and simvastatin (Zocor). Greater reductions of 2–3 mmol/L are associated with a 40–50% reduction in the risk of stroke. However, two large trials suggested that the use of statins could increase the risk of hemorrhagic stroke (bleeding resulting from a weakened blood vessel) by 67%.

Immediate and sustained implementation of effective and appropriate prevention strategies in patients with first-ever stroke or transient ischemic attack has the potential to reduce the risk of secondary stroke.