White matter hyperintensities, brain infarcts, and cerebral microbleeds are important biomarkers potentially predictive of the risk for stroke, dementia, and death in community-dwelling older adults, according to a study published in JAMA Neurology.
Data from 94 prospective, longitudinal studies published between 1966 and 2017, which assessed the association of 4 magnetic resonance imaging (MRI) markers of covert vascular brain injury with incident stroke, dementia, or death, were pooled from PubMed. Studies included in the review and meta-analysis were only included if they had ≥50 participants. Markers of covert vascular brain injury in this analysis included white matter hyperintensities of presumed vascular origin, MRI-defined covert brain infarcts, cerebral microbleeds, and perivascular spaces. The main outcomes of interest included hemorrhagic and ischemic stroke, dementia, and death.
In the pooled cohort, a total of 14,529 participants had white matter hyperintensities, 16,012 participants had brain infarcts, 15,693 participants had cerebral microbleeds, and 4587 participants had perivascular spaces.
Patients presenting with substantial and extensive white matter hyperintensity burden had a higher risk for incident stroke (hazard ratio [HR] 2.45; 95% CI, 1.93-3.12; P <.001), ischemic stroke (HR 2.39; 95% CI, 1.65-3.47; P <.001), intracerebral hemorrhage (HR 3.17; 95% CI, 1.54-6.52; P =.002), dementia (HR 1.84; 95% CI, 1.40-2.43; P <.001), Alzheimer disease (HR 1.50; 95% CI, 1.22-1.84; P <.001), and death (HR 2.00; 95% CI, 1.69-2.36; P <.001).
In addition, the researchers found that MRI-defined brain infarcts increased the risk for ischemic stroke (HR 2.18; 95% CI, 1.67-2.85; P <.001), intracerebral hemorrhage (HR 3.81; 95% CI, 1.75-8.27; P <.001), incident stroke (HR 2.38; 95% CI, 1.87-3.04; P <.001), and death (HR 1.64; 95% CI, 1.40-1.91; P <.001).
There was also an association between the presence of cerebral microbleeds and a significant increase in the risk for intracerebral hemorrhage (HR 3.82; 95% CI, 2.15-6.80; P <.001), stroke (HR 1.98; 95% CI, 1.55-2.53; P <.001), ischemic stroke (HR 1.92; 95% CI, 1.40-2.63; P <.001), and death (HR 1.53; 95% CI, 1.31-1.80; P <.001).
Data on perivascular spaces were limited and insufficient to conduct meta-analyses. Although there was an association of high perivascular spaces burden with increased risk for stroke, dementia, and death, this requires confirmation.
Limitations of the study were the inclusion of only studies reported in English, as well as the post hoc nature of the meta-analyses.
Additional research, including randomized controlled trials, may be necessary “to determine whether specific therapies, particularly aspirin therapy and intensive blood pressure lowering, are beneficial when these MRI markers are noted as incidental findings,” the researchers concluded.
Debette S, Schilling S, Duperron MG, Larsson SC, Markus HS. Clinical significance of magnetic resonance imaging markers of vascular brain injury: a systematic review and meta-analysis [published online October 22, 2018]. JAMA Neurol. doi: 10.1001/jamaneurol.2018.3122