Cerebral Microbleeds, Stroke, and Atrial Fibrillation: The Connection

Mark J. Alberts, MD


March 12, 2015

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Hello and welcome to this Medscape stroke update. My name is Dr Mark Alberts, vice chair of neurology at UT-Southwestern Medical Center in Dallas, Texas.

Today I would like to share a very interesting study with you that was published in the journal Neurology.[1] This study was done by Dr Song and colleagues in Seoul, South Korea.

They enrolled more than 500 patients who presented with ischemic strokes and atrial fibrillation. All of the patients underwent a brain MRI scan to see how many had cerebral microbleeds, the degree of cerebral microbleeds, and their location. These patients were followed for 2.5 years. The mean age was 71 years and all had typical cardiovascular disease risk factors, such as hypertension, diabetes, and hyperlipidemia.

They found overall with MRI studies that 31% of this patient cohort with ischemic stroke and atrial fibrillation had cerebral microbleeds. After 2.5 years of follow-up they found that slightly more than one third (35%) had died. The vast majority died from ischemic heart disease or ischemic stroke, not necessarily cerebral hemorrhage. In fact, only 2.4% of the patients had a cerebral hemorrhage.

What about anticoagulation? Most (approximately 95%) of this patient cohort was anticoagulated, because they presented with an ischemic stroke in the setting of atrial fibrillation.

Of interest, however, was that the distribution and number of cerebral microbleeds were highly predictive of all-cause mortality, as well as mortality from ischemic stroke or heart disease.

Patients who had many lobar hemorrhages were more likely to also have a cerebral hemorrhage, but the overall proportion with a cerebral hemorrhage was only 2.4%.

What can we take away from this fairly large study? Cerebral microbleeds appear to be a marker for many bad outcomes, particularly all-cause mortality, ischemic stroke, and ischemic heart disease. There is a risk for cerebral hemorrhage in this patient population, but overall it appears to be small, or at least smaller than I would have anticipated, except in patients who have many microbleeds in a lobar location.

We will have to see how this story evolves over the next few years. Keep in mind that all of these patients were anticoagulated, so it should be somewhat reassuring that this patient cohort can be treated with anticoagulation without a huge increase in fatal cerebral hemorrhages. Maybe this group just needs better control of such cardiovascular risk factors as hypertension, diabetes, hyperlipidemia, etc.


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