The Effect of Antithrombotics on Hematoma Expansion in Small- to Moderate-Sized Traumatic Intraparenchymal Hemorrhages

Abstract

Although pre-injury antithrombotic agents, including antiplatelets and anticoagulants, are historically associated with expansion of traumatic intraparenchymal hemorrhage (tIPH), the literature has poorly elucidated the actual risk of hematoma expansion on repeat computed tomography (CT). The objective was to determine the effect of antithrombotic agents on hematoma expansion in tIPH by comparing patients with and without pre-injury antithrombotic medication. The volume of all tIPHs over a 5-year period at an academic Level 1 trauma center was measured retrospectively. The initial tIPH was divided into 3 equally sized quantiles. The third tercile, representing the largest subset of tIPH, was then removed from the study population because these patients reflect a different pathophysiologic mechanism that may require a more acute and aggressive level of care with reversal agents and/or operative management. Per institutional policy, all patients with small- to moderate-sized hemorrhages received a 24-hour stability CT scan. Patients who received reversal agents were excluded. Of the 105 patients with a tIPH on the initial head CT scan, small- to moderate-sized hemorrhages were <5 cm3. The size of tIPH on initial imaging did not statistically significantly differ between the antithrombotic cohort (0.7 ± 0.1 cm3) and the non-antithrombotic cohort (0.5 ± 0.1 cm3) (P= 0.091). Similarly, the volume of tIPH failed to differ on 24-hour repeat imaging (1.0 ± 0.2 cm3 vs. 0.6 ± 0.1 cm3, respectively, P= 0.172). Following a multiple linear regression, only history of stroke, not antithrombotic medications, predicted increased tIPH on 24-hour repeat imaging. In small- to moderate-sized tIPH, withholding antithrombotic agents without reversal may be sufficient.