Prevalence And Predictors Of Cerebral Microbleeds Among Racial Minorities With Ischemic Stroke And Transient Ischemic Attack.

Background: Cerebral microbleeds (CMB) are associated with dementia and stroke. CMB are attributed to cerebral amyloid angiopathy (lobar CMB), and hypertensive angiopathy (deep CMB). Racial minorities (RM) have a higher prevalence and poorer control of vascular risk factors, thus CMB may differ in prevalence and distribution in RM. We determined the prevalence, burden and vascular risk factors of CMB across racial groups in patients with stroke and transient ischemic attack, and CMB influence in short term outcomes. Methods: We included 2001 consecutive (year 2009-2018) patients with a readable T2*gradient-echo MRI sequence. CMB rating followed standardized guidelines and grouped topographically into lobar, deep or infratentorial. Race was self-reported based on U.S. census procedures and categorized as White, Black or Other racial groups (ORG). Univariate analyses were done to compare vascular risk factors between CMB groups, and multivariate logistic regression analyses were used to relate CMB and short term functional (modified Ranking scale score <3 vs. higher) and adverse hospital outcomes (pneumonia, UTI, DVT, death), across racial groups. Results: We observed CMB in 679 (34%) patients. The respective distribution in lobar, deep and infratentorial regions were: Whites (n=174; 67.2%, 20.7% and 12%); Blacks (n=374; 53%, 28.4% and 18.5%); ORG (n=131; 45.5%, 25.3% and 29.3%). Blacks and ORG with CMB were younger than Whites (66 and 66 vs 70; p<0.01); and had higher prevalence of diabetes (44% and 41% vs 28%, p<0.01). Blacks had higher prevalence of previous stroke when compared with Whites (36% vs 27%, p<0.05). Patients with 10+ CMB, compared with no CMB and 1-9 CMB, had higher in-hospital pneumonia (8% vs 2.1% and 2.4% respectively; p=0.02) and were less likely to have mRS 0-2 at discharge (44.8% vs 55.3% and 48.7%; p=0.06). No difference was observed in mortality and other hospital adverse events. Conclusion: Racial minorities had higher proportion of CMB in non-lobar regions, suggesting that RM are more likely to have hypertensive angiopathy. RM with CMB were younger and differed in several risk factors compared to Whites. High CMB burden affected adversely outcomes. Further studies are needed to better characterize the clinical impact of CMB in RM.