Hematoma Expansion Differences in Lobar and Deep Primary Intracerebral Hemorrhage

Hematoma expansion (HE) after intracerebral hemorrhage (ICH) is associated with worse outcome. Lobar ICHs are known to have better outcomes compared to deep ICH; however, it is unclear whether there are HE differences between these locations. We sought to investigate the hypothesis that lobar ICH has less HE compared to deep ICH.

Primary ICH patients admitted between 2009 and 2016 were included in a prospective single-center ICH cohort study. Patients with preceding anticoagulant use, coagulopathy on admission labs, or presenting after 24 h from symptom onset were excluded. Lobar and deep ICH patients with baseline and follow-up computed tomography (CT) (within 24 h of admission CT) were evaluated. HE was defined primarily as relative growth > 33% given expected baseline hematoma volume differences between locations. Other commonly utilized definitions of HE: > 6 mL, and > 33% or > 6 mL, were additionally assessed. Multivariable logistic regression was used to assess the association of ICH location with HE while adjusting for previously identified covariates of HE.

There were 59 lobar and 143 deep ICH patients analyzed. Lobar ICH patients had significantly larger baseline hematoma volumes, lower admission systolic blood pressure, and longer times to admission CT compared to deep ICH. Multivariable logistic regression revealed an association of lobar ICH with lower odds of HE (> 33%) [odds ratio (OR) 0.32; 95% confidence interval (CI) 0.11-0.93; p = 0.04] compared to deep ICH after adjusting for baseline ICH volume, blood pressure, and time to CT. Secondary analysis did not identify an association of lobar ICH with HE defined as > 6 mL (adjusted OR 1.44; 95% CI 0.59-3.50; p = 0.41) or > 33% or > 6 mL (adjusted OR 0.71; 95% CI 0.29-1.70; p = 0.44).

We identified less HE in lobar compared to deep ICH. The use of absolute growth thresholds in defining HE may be limited when assessing groups with largely different baseline hematoma sizes. Further study is required to replicate our findings and investigate mechanisms for HE differences between lobar and deep ICH locations.