Can brain bleeds increase the risk of recurrent stroke?

The authors of this meta-analysis attempted to determine whether cerebral microbleeds increased the risk of recurrent ischemic stroke and intracerebral hemorrhage in patients who had an ischemic stroke. They concluded that patients with cerebral microbleeds had a higher risk of recurrent ischemic stroke and intracerebral hemorrhage than patients without cerebral microbleeds.

Cerebral microbleeds (CMBs) are bleeds in the brain, most likely due to structural problems with blood vessels in the brain. In patients with ischemic stroke (stroke caused by a blocked blood vessel in the brain), CMBs can be associated with recurring ischemic strokes or with intracerebral hemorrhage (ICH, bleeding within the brain tissue). Whether CMBs result in a higher risk of either recurrent ischemic stroke or ICH remains unknown.

The authors aimed to determine whether there is a higher risk of recurrent ischemic stroke or ICH due to CMBs in patients who had an ischemic stroke.

This meta-analysis included 15 studies and a total of 5068 patients. Of these patients, 1284 had CMBs. Patients were followed for an average of 18 months.

There were a total of 327 patients with recurrent ischemic stroke (6.5%). 9% of patients with CMBs experience a recurrent stroke, compared to 5.6% of those without. 

There were a total of 66 patients with ICH. 4.3% of patients with CMB experienced an ICH, compared to 0.5% of those without. 

CMBs increased the risk of recurrent ischemic stroke by 3.4%, and the risk of ICH by 3.8%. These risk values were highest in patients with higher amounts of CMBs.

The authors concluded that CMBs result in an increased risk of both recurrent IS and ICH in patients who have had an ischemic stroke. They also determined that this risk increases as CMB burden increases. 

A large amount of patients in these studies were treated with anti-platelet drugs and therefore it is not clear whether these results would be the same in patients treated with anti-coagulant drugs.