Practice Guidelines

Secondary Prevention of Ischemic Stroke: Updated Guidelines From AHA/ASA

 

Am Fam Physician. 2022 Jan ;105(1):99-102.

Author disclosure: No relevant financial relationships.

Key Points for Practice

• In embolic stroke of an uncertain source, further workup with long-term cardiac monitoring, transesophageal echocardiography, and cardiac magnetic resonance imaging should be considered.

• In nonembolic strokes, antiplatelet therapy and cardiovascular risk reduction can reduce recurrent stroke risk.

• Neither anticoagulation nor antithrombotic therapy appears to reduce risk in embolic stroke of uncertain source.

From the AFP Editors

Stroke is a common source of morbidity and mortality in the United States. Between 20% and 25% of strokes occur in patients with a previous stroke or transient ischemic attack. More than 90% of the global stroke burden can be traced to the modifiable risk factors of blood pressure, diet, physical inactivity, smoking, and abdominal obesity. The American Heart Association and American Stroke Association (AHA/ASA) published updated guidelines for preventing recurrent ischemic stroke, focusing on overall cardiovascular risk reduction and targeted secondary prevention.

Stroke Subtype Classification

Ischemic strokes account for nearly 90% of strokes in the United States. The TOAST (Trial of Org 10172 in Acute Stroke Treatment) classification scheme groups ischemic strokes into lacunar or nonlacunar subtypes. Lacunar strokes present with a specific syndrome pattern and can have normal imaging or subcortical ischemic areas less than 0.6 in (1.5 cm) in diameter.

Nonlacunar strokes can be caused by cardioembolism, large artery atherosclerosis, and cryptogenic sources. Cardioembolic sources are suggested when previous or current ischemia occurs in multiple vascular territories. Large artery atherosclerotic lesions may present with cortical, brainstem, cerebellar, or larger subcortical areas of ischemia. Cryptogenic strokes defy characterization despite complete evaluations and again subdivide into embolic or nonembolic strokes of uncertain source. Embolic strokes of an uncertain source are nonlacunar and appear embolic, but no source of embolus can be identified. Figure 1 details the relative frequency of different stroke subtypes.

FIGURE 1.

Stroke subtypes.


FIGURE 1.

Stroke subtypes.

Diagnostic Evaluation

After a stroke, the subtype can usually be determined from initial testing, including computed tomography, magnetic resonance imaging, electrocardiography, continuous cardiovascular monitoring, echocardiography, and laboratory analyses. When initial imaging does not show ischemia after a stroke, imaging can be repeated seven days after the index event to look for ischemic changes.

Extracranial carotid imaging and contrast imaging studies can be performed with the initial evaluation. Carotid imaging is vital for strokes affecting the anterior circulation, and vertebrobasilar imaging is recommended for strokes outside of the anterior circulation.

For cryptogenic stroke without a suspected embolic source, testing for hypercoagulation and vasculitis should be considered. If an embolic source is suspected, further testing with long-term or implantable cardiac rhythm monitoring, transesophageal echocardiography, or cardiac magnetic resonance imaging is recommended. In embolic strokes of an uncertain source, findings from transesophageal echocardiography will change management in 14% of patients. Up to 16% of patients with embolic strokes of an uncertain source will have paroxysmal atrial fibrillation identified with prolonged cardiac monitoring. Evidence is insufficient to recommend a specific prolonged cardiac monitoring strategy for these patients.

Secondary Cardiovascular Prevention

Secondary stroke prevention includes cardiovascular risk reduction, as shown in Table 1. AHA/ASA guidelines recommend a blood pressure treatment goal of less than 130/80 mm Hg after all strokes and low-density lipoprotein cholesterol goals of less than 70 mg per dL (1.81 mmol per L) for nonembolic strokes. If triglycerides are greater than 135 mg per dL (1.53 mmol per L) in nonembolic strokes, adding icosapent ethyl can reduce the risk of current stroke but increase the risk of atrial fibrillation. A Mediterranean-type diet is the primary dietary recommendation, and limiting salt to 2.5 g daily is reasonable. AHA/ASA recommends at least four weekly 10-minute periods of moderate-intensity physical activity or two high-intensity 20-minute periods. Smoking cessation is strongly recommended, and alcohol cessation or reduction to no more than two drinks per day for men and no more than one per day for women is recommended.

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TABLE 1.

Cardiovascular Risk Reduction After Stroke

Risk domainManagement strategyExplanation

Alcohol

Elimination or reduction in alcohol consumption in males drinking more than two and females drinking more than one alcoholic drink a day

3.8% of strokes are estimated to be attributed to alcohol

Coverage of guidelines from other organizations does not imply endorsement by AFP or the AAFP.

This series is coordinated by Michael J. Arnold, MD, contributing editor.

A collection of Practice Guidelines published in AFP is available at https://www.aafp.org/afp/practguide.

 

 

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