Secondary Prevention, Vascular Risk Factors, and Atherosclerotic Disease
Core concepts
Secondary prevention begins with mechanism. Use TOAST-type reasoning to separate large-artery atherosclerosis, cardioembolism, small-vessel disease, other determined causes, and undetermined stroke. Noncardioembolic stroke usually receives antiplatelet therapy; aspirin, clopidogrel, or aspirin-dipyridamole are options. Short-term dual antiplatelet therapy is appropriate for selected minor stroke or high-risk TIA and after recent symptomatic carotid stenting, but chronic dual therapy increases bleeding. Anticoagulation is indicated for atrial fibrillation and other high-risk cardioembolic sources, with timing individualized by infarct size and hemorrhage risk. High-intensity statin therapy is standard for atherosclerotic stroke. Control blood pressure, diabetes, smoking, obesity, and physical inactivity. Carotid endarterectomy benefits selected symptomatic severe stenosis, ideally within two weeks; carotid stenting is an alternative in favorable anatomy or high surgical risk. Asymptomatic severe stenosis may be considered in selected patients. Intracranial atherosclerotic disease is managed with aggressive medical therapy rather than routine stenting. Do not confuse patent foramen ovale closure, which is selected for young patients with cryptogenic stroke and high-risk shunt features, with routine treatment.
Traps
Do not start anticoagulation immediately after a large infarct without weighing hemorrhagic transformation. Do not use dual antiplatelet therapy indefinitely. Do not label small-vessel disease as atherosclerotic large-vessel disease without imaging. Do not overlook sleep apnea and renal disease.
Worked example
A 70-year-old with minor nondisabling stroke, 70 percent symptomatic carotid stenosis, and atrial fibrillation: treat the acute stroke, plan timely carotid revascularization, and anticoagulate for atrial fibrillation when safe. Mechanism-specific therapy beats a single default prescription.