Secondary prevention of stroke

Patients with a history of stroke or TIA are at much higher risk of suffering a further stroke. Consequently reducing stroke risk following a TIA or a stroke is a major goal. Studies show that the risk of stroke following a TIA is about 12% in the first year and then 7% per annum; a seven fold increase in risk compared to the normal population (1). The urgency of specialist TIA assessment is discussed in the linked page.

Once intracranial haemorrhage has been excluded by CT scan, the principles of secondary stroke prevention are:

• antiplatelet therapy
  • aspirin should be started within the first 24 hr, then aspiring 300 mg/day should be commence
    • aspirin should be taken for 2 weeks after the onset of symptoms and then definitive anti-platelet therapy should be commenced
  • patients with stroke or TIA should receive two weeks of aspirin followed by definitive anti-platelet treatment (2):
    • following a stroke:
      • first line: long-term treatment with clopidogrel
      • second line: long-term treatment with modified-release (MR) dipyridamole plus aspirin is only recommended if clopidogrel is contraindicated or not tolerated
      • third line: long-term treatment with MR dipyridamole alone is only recommended if the first and second line treatments are contraindicated or not tolerated
    • following a TIA:
      • first line: long-term treatment with MR dipyridamole plus aspirin
      • second line: long-term treatment with MR dipyridamole alone is only recommended if the first line treatment is contraindicated or not tolerated
      • note that clopidogrel is not licensed for secondary stroke prevention after TIA
        
        
• anticoagulant therapy for patients with atrial fibrillation:
  • there is no place for anticoagulant therapy in managing patients with stroke who are in sinus rhythm
  • however where oral anticoagulation is contraindicated, an antiplatelet drug, such as aspirin, may be appropriate (2)
    
    
• diabetic patients should be well controlled

In the medium term consider:

• carotid endarterectomy:
  • highly beneficial in symptomatic patients with 70-99% stenosis of the internal carotid
• modification of general risk factors for stroke including:
  • hypertension:
    • only hypertensive emergencies are treated acutely post stroke
    • medium term treatment of hypertension will reduce risk of stroke
  • cholesterol
  • smoking

Notes:

• if there is a history of dyspepsia associated with aspirin or clopidogrel should also be given a proton pump inhibitor
• if there is a history of aspirin intollerance then an alternative antiplatelet agent should be given

References:

• (1) Williams B, Poulter NR, Brown MJ, Davis M, McInnes GT, Potter JF, et al. Guidelines for management of hypertension: report of the fourth working party of the British Hypertension Society, 2004:BHS IV. J Hum Hypertens 2004;18: 139-85
• (2) NICE (December 2010) - Clopidogrel and modified-release dipyridamole in the prevention of occlusive vascular events
• (3) Drug and Therapeutics Bulletin 2005; 43(7): 53-6.