Illicit drug use and cerebral microbleeds in patients with acute ischemic stroke and transient ischemic attack

Cerebral microbleeds (CMB) signal cerebral small vessel disease and are associated with ischemic stroke. While illicit drug use (IDU) is linked to cerebral vasculopathy, the association between CMB and IDU is poorly characterized.

Our primary aim was to explore the relationship between IDU and CMB and delineate differences in vascular risk factors between those with and without CMB.

We included 1746 (1614 unique patients) acute ischemic stroke and transient ischemic accident patient admissions from 2009 to 2018 with a readable T2*gradient-echo sequence brain magnetic resonance imaging (MRI). We retrospectively obtained patient characteristics and IDU data (by history and/or urine toxicology). MRIs were reviewed for CMB and classified topographically as lobar, deep, or infratentorial. Univariate analysis was used to assess differences in patient characteristics between those with and without CMB, as well as variation in CMB location by drug category subgrouping. Coprimary multivariate logistic/Poisson regression was used to characterize the association between drug category subgrouping and CMB.

We observed IDU in 13.8% (n = 241) and CMB presence in 32.9% (n = 575) in our predominantly black, middle-aged population. 53.8% of CMB were lobar, 27.3% were deep, and 18.8% were infratentorial. Within the IDU group, those with at least one CMB (compared to those without CMB) were older (56.9 ± 11.5 vs 53.6 ± 10.5, p = 0.036), had a lower body mass index (26.6 ± 4.4 vs 28.1 ± 5.9, p = 0.039), and were more likely to have chronic kidney disease (9.5% vs 3.0%, p = 0.033) or have had a previous ischemic stroke/transient ischemic attack (41.9% vs 25.1%, p = 0.009). On coprimary analysis, cocaine use was associated with increased CMB number by 0.24 (95% confidence interval (CI): 0.09, 0.38; p = 0.001) and opioid use was associated with increased CMB number by 0.31 (95% CI: 0.08, 0.52; p < 0.001) controlling for age, sex, hypertension status, and prior ischemic stroke or transient ischemic accident. CMB in the opioid use group were more likely to be deep (40.4% vs 27.3%, p = 0.023) compared to those without opioid use.

Our findings support an association between CMB, an early marker of cerebral vasculopathy, and cocaine and opioid use. These results highlight the need for further research into the pathophysiological mechanisms linking IDU to cerebrovascular injury and underscore the importance of targeted interventions in this population.