Hematoma expansion in intracerebral hemorrhage retrospective chart review: Who are the super-expanders?

Hematoma expansion in intracerebral hemorrhage (ICH) is a predictor of poor outcome and remains an important therapeutic target. Little is known about the incidence and clinical characteristics of patients with severe hematoma expansion, who we hereafter label as super-expanders.

We retrospectively reviewed baseline clinical and radiological features in consecutive ICH patients admitted over a three-year period to a comprehensive stroke center. Hematoma expansion was defined conventionally as a > 33 % increase in hematoma volume or a > 6 ml increase in absolute hematoma volume between the baseline and 24-hour follow-up brain CT. Severe hematoma expansion was defined as a > 50 % increase in ICH volume associated with a decrease in the Glasgow Coma Scale of at least four points. We used Random Forest (RF) to generate importance plots searching for the determinants of super-expanders in ICH. In addition, a multivariable logistic regression model was done to examine independent factors associated with super-expanders.

We analyzed 417 cases. Hematoma expansion, defined conventionally, occurred in 97/417 (23 %) patients of which 15/417 (4 %) were super-expanders. In the univariate analysis, super-expanders were more likely to have a lobar hemorrhage, spot sign, and increased in-hospital mortality. Using the RF analysis, age, platelet count, and presence of a spot sign emerged as important determinants of super-expansion. In a multivariable model, only spot sign was an independent predictor for super-expansion [Age (OR = 1.43, 95 % CI=0.61-3.37), spot sign (OR = 6.25, 95 % CI=2.30-17.00), lobar location (OR = 4.63, 95 % CI= 0.92-23.42)].

We describe a low incidence of 4 % of severe hematoma expansion in ICH. There were no definitive clinical or radiological characteristics that differentiated super-expanders. Identifying such characteristics may allow for patient risk stratification. We encourage further investigations into the early identification of super-expanders, who arguably have the most to benefit from aggressive interventions.