Cerebral Microbleeds Post Transient Ischemic Attacks

Cerebral microbleeds (CMBs) following a transient ischemic attack (TIA) may be a sign a patient is likely to have another stroke. All patients who have a TIA are at risk of a recurrence, but that risk can be modified by optimal treatment, Jae-Sung Lim, MD, MSc and colleagues report. In fact, 80% of those recurrences could be eliminated, Lim wrote in a study in JAMA Neurology. But that may not be the case with TIA patients who have CMBs.

The team looked at 500 TIA patients in 11 university hospitals in Korea from July 2010 through December 2012 and followed them for 90 days.

Within that 90 days, 5% had recurrences.

“It is noteworthy that CMBs were substantially and independently associated with an increased risk of recurrent stroke after TIA,” the researchers wrote.

They cite a European study that put that risk at 9 times greater than in TIA patients without a CMB.

That finding is likely because a CMB is a sign of vessel fragility and endothelial instability, they wrote. But it could also be that the CMB harmed small vessels, resulting in in-situ thrombosis and reduced arterial flow distal to the bleed.

The medications that prevent recurrent stroke post-TIA in patients with large artery atherosclerosis or cardioembolism (statins, antiplatelets, and anticoagulants) “Might not effectively block the mechanisms of recurrent stroke related to CMB conditions,” they wrote. Those could be hypertension or cerebral amyloid angiopathy.

“Physicians’ avoidance of prescribing antithrombotics because of concern of hemorrhagic stroke in patients with CMBs may be an issue,” said the authors.

The study’s limits, as outlined by the authors, are that it had a small number of patients with subsequent strokes. That could mean “there are possibilities that our study might be underpowered to detect the effects of various factors” causing recurrences—other than CMBs.

The participants were all Asian, a population with a higher proportion of small vessel occlusion in stroke mechanism.

Also, all patients were treated in comprehensive stroke centers, so some findings cannot be generalized.

“Nevertheless, our study has notable strengths,” they noted, including the facts that the 500 patients were treated with the same set of protocols in the same time frame and 100% of them were followed 90 days.

That should provide a foundation for further research, including the finding that CMB after TIA predicts a recurrent stroke.