Silent Cerebrovascular Disease Increases Risk for Future Stroke

Individuals with silent cerebrovascular disease are at higher risk for future symptomatic stroke, according to an American Heart Association/American Stroke Association (AHA/ASA) scientific statement published in Stroke.

Silent cerebrovascular disease may manifest as silent brain infarcts, microbleeds, or white matter lesions of presumed vascular origin (white matter hyperintensities on magnetic resonance imaging [MRI] or white matter hypodensity on computed tomography).

“Silent cerebrovascular disease is a very common incidental finding on brain scans. For example, 1 or more silent brain infarcts are seen on scans in more than 25% of persons over 80 years old,” Eric Smith, MD, MPH, from the University of Calgary, Alberta, Canada, told Cardiology Advisor. “The question is: What do we do about this information?”

Although silent cerebrovascular disease is not associated with clinical stroke symptoms, epidemiological data show that individuals with silent cerebrovascular disease experience motor and cognitive dysfunction, including gait impairment and cognitive decline. In addition, stroke risk is increased in patients with silent brain infarcts and white matter hyperintensities.

The AHA Stroke Council writing committee, led by Dr Smith, performed a systematic literature review to evaluate the evidence for the diagnosis and management of silent cerebrovascular disease for the prevention of future symptomatic stroke.

“Our literature review identified clear evidence that patients with silent cerebrovascular disease are at higher risk of future symptomatic stroke,” Dr Smith said. Although no randomized controlled trials examined stroke prevention in patients with silent cerebrovascular disease, the committee recommends following AHA/ASA guidelines for primary stroke prevention in this population.

“The stroke risk associated with silent cerebrovascular disease should be considered when making decisions about the use of antithrombotic therapy and statins, as well as anticoagulation if atrial fibrillation is present,” Dr Smith said. “However, information from MRI has not yet been formally incorporated into risk prediction scores, such as the CHA₂DS₂-VASC score, for stroke risk in atrial fibrillation.”

Limited data suggest that the risk for intracranial hemorrhage (ICH) may be increased among patients with silent cerebral microbleeds, particularly among those who are treated with anticoagulation. In addition, patients with microbleeds were found to have higher rates of symptomatic ICH after thrombolysis for acute ischemic stroke, and although microbleeds are associated with greater ICH risk overall, they may also raise the risk for future ischemic stroke.

“We did not find evidence that the increased risk of ICH in patients with microbleeds was proven to outweigh the benefits of anticoagulants and thrombolytics,” Dr Smith noted. “Therefore, we suggest that patients with microbleeds should be treated with antithrombotics, anticoagulants, or thrombolytics if they are otherwise indicated.”

In summarizing the evidence on silent cerebrovascular disease, the committee identified several areas that require further investigation, particularly because no randomized controlled trials have been conducted to evaluate the diagnosis and management of silent cerebrovascular disease.

“Future studies could add brain MRI information to cardiovascular and stroke risk scores, such as the AHA/[American College of Cardiology] risk calculator or the CHA₂DS₂-VASC score for atrial fibrillation, so that information on silent strokes can be formally incorporated into clinical decision making on stroke prevention,” Dr Smith said. “Studies of new cardiovascular prevention strategies should ideally include substudies of patients with brain MRI to see the effect of new treatments in patients with silent strokes and to see if they prevent new silent strokes.”

Reference

Smith EE, Saposnik G, Biessels GJ, et al; on behalf of the American Heart Association Stroke Council; Council on Cardiovascular Radiology and Intervention; Council on Functional Genomics and Translational Biology; and Council on Hypertension. Prevention of stroke in patients with silent cerebrovascular disease: a scientific statement for healthcare professionals from the American Heart Association/American Stroke Association [Published online December 15, 2016]. Stroke. doi: 10.1161/STR.0000000000000116