Background and Purpose- The frequency and prognostic implications of incident cerebral microbleeds (CMB), defined as development of one or more new CMB, after intracerebral hemorrhage (ICH) is unclear. Therefore, we performed a systematic review and meta-analysis to investigate the frequency and prognostic implications of incident CMB after ICH. Methods- We searched Ovid Medline and Embase in May 2018 for longitudinal studies of adults who underwent brain magnetic resonance imaging at 2 or more times after ICH. We calculated the pooled proportion of adults with incident CMB and sought associations between incident CMB and clinical outcomes (death, recurrent ICH, or new ischemic stroke). We planned subgroup analyses to investigate clinical variables associated with incident CMB. Results- We identified 2354 publications, of which we included 4 cohort studies involving 349 patients. The pooled proportion of adults with at least one new CMB during a mean 27 months follow-up (SD 20 months) was ≈40% (95% CI, 30%-50%). In one study, as the number of incident CMB increased (0 versus 1-3 new CMB versus ≥4 new CMB) the risk of recurrent symptomatic lobar ICH increased (hazard ratio 3.0; 95% CI, 1.2-7.3). No study reported on outcomes of incident ischemic stroke or death. Conclusions- Incident CMB occurs in ≈40% of adults after ICH. The association of incident CMB with recurrent lobar ICH needs confirmation and their association with death and ischemic stroke investigation.
Keywords: brain; cerebral hemorrhage; magnetic resonance imaging; meta-analysis; review.