Non-contrast CT Markers of Hematoma Expansion and Andexanet Response in Factor Xa Inhibitor-Associated Intracerebral Hemorrhage: An Analysis from ANNEXa-I Trial.
Koji Tanaka, Umberto Pensato, Mohamed Alshamrani et al.
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In 30 seconds
This post hoc analysis of the randomized ANNEXa-I trial assessed non-contrast CT markers of hematoma expansion in patients with factor Xa inhibitor-associated intracerebral hemorrhage. Among 434 participants, at least one marker was present in 72.1%, and hematoma expansion—defined as ≥12.5 mL or ≥35% increase in hematoma volume—occurred in 31.8%. Heterogeneous density, hypodensity, and the black hole sign were independently associated with expansion. Andexanet’s effect on expansion was generally consistent across marker subgroups, suggesting these imaging features identify risk rather than clearly distinguishing treatment response.
Key findings
- At least one non-contrast CT marker was present in 72.1% of participants.
- Hematoma expansion occurred in 31.8%, using the threshold of ≥12.5 mL or ≥35% increase in hematoma volume.
- Heterogeneous density, hypodensity, and the black hole sign were independently associated with hematoma expansion.
- Andexanet’s effect on hematoma expansion was generally consistent across non-contrast CT marker subgroups.
Why it matters
Non-contrast CT is used to assess intracerebral hemorrhage, and these findings indicate that specific density patterns may help identify patients at higher risk of hematoma growth in the setting of factor Xa inhibitor use. The broadly consistent andexanet effect across marker subgroups also cautions against interpreting these markers as evidence of differential treatment response.
What to keep in mind
This was a post hoc analysis of a trial, rather than a study designed specifically to validate CT markers or assess treatment effects within marker subgroups.