For a patient who has already had a stroke and wants to lower the risk of another, which level of prevention applies: primary, secondary, or tertiary?

Secondary Prevention

This is secondary prevention—the patient has already experienced a stroke and is now seeking to prevent recurrence. 1

Understanding Prevention Levels in Stroke

Secondary Prevention Definition

• Secondary prevention specifically targets patients who have already had a stroke or transient ischemic attack (TIA) to reduce the risk of recurrent events. 1
• The focus is on aggressive vascular risk factor reduction and mechanism-specific interventions after the index stroke event. 1
• This differs fundamentally from primary prevention, which aims to prevent a first stroke in asymptomatic individuals at risk. 1, 2, 3

Why This Scenario is Secondary Prevention

• The patient has already sustained a stroke (the "index event"), making any subsequent preventive measures secondary prevention by definition. 1
• Canadian data indicate that even stroke survivors free of immediate post-stroke complications remain at significantly increased risk for cardiovascular events long-term, creating the opportunity for aggressive secondary prevention. 1
• Approximately one out of four strokes is recurrent, underscoring the critical importance of secondary prevention strategies. 4

Distinguishing from Other Prevention Levels

Primary Prevention:

• Targets asymptomatic individuals who have never had a stroke but may have risk factors. 1, 2
• Includes measures like blood pressure control in hypertensive patients without prior stroke, smoking cessation in healthy smokers, and anticoagulation for atrial fibrillation in patients without prior cerebrovascular events. 1, 3

Tertiary Prevention:

• Focuses on managing complications and disabilities after stroke has occurred, promoting rehabilitation and reintegration. 1
• Includes physical therapy, occupational therapy, speech therapy, and preventing secondary complications like contractures or aspiration pneumonia. 5
• The goal is to minimize the impact of established disease and improve quality of life rather than prevent recurrence. 1

Clinical Context

• The 2021 American Heart Association/American Stroke Association guidelines specifically address "prevention of stroke in patients with stroke and transient ischemic attack," which is the definition of secondary prevention. 1
• The Canadian Stroke Best Practice Recommendations explicitly state that their secondary prevention module focuses on "recurrent stroke risk reduction in patients who have experienced a stroke or transient ischemic attack." 1
• Secondary prevention encompasses both conventional vascular risk factor management (blood pressure, lipids, diabetes, antiplatelet therapy) and mechanism-specific interventions (carotid endarterectomy, anticoagulation for atrial fibrillation, patent foramen ovale closure). 1, 6, 7, 8