Secondary prevention of ischemic stroke: evolution from a stepwise to a risk stratification approach to care.

Survivors of ischemic stroke are at significant risk for recurrent stroke. Appropriate therapy for stroke prevention is needed given the significant morbidity and mortality associated with stroke, the high financial costs, and the neurologic disability associated with treatment failure. A treatment strategy based on assessed risk represents an appropriate use of medical resources and results in improved outcomes. This approach requires evaluation of major risk factors, the most serious of which is a history of ischemic stroke or transient ischemic attack. The annual risk for recurrent stroke is 6% during the first 5 years after an initial stroke. Non-modifiable risk factors include age, race, ethnicity, gender, family history, and geography. The most important modifiable risk factor is hypertension. Diabetes mellitus, hyperlipidemia, left ventricular hypertrophy, atrial fibrillation, and lifestyle factors such as smoking, alcohol abuse, and obesity contribute to stroke risk. Antihypertensive, lipid-lowering, and antiplatelet therapies have been successful in reducing the incidence of secondary stroke. Clinical trials validate the benefits of statin therapy in reducing the risk for secondary stroke. Studies of antiplatelet agents, including aspirin, clopidogrel, and aspirin combined with extended-release dipyridamole, have evaluated the risk reduction in recurrent stroke and have been concerned particularly with the risk for hemorrhage. Therapy for stroke prevention based on risk stratification can identify patients who are appropriate targets for aggressive intervention.