Interrupted pharmocologic thromboprophylaxis increases venous thromboembolism in traumatic brain injury.

Background: Pharmacologic thromboprophylaxis (PTP) is frequently withheld, begun late, or interrupted in patients with traumatic brain injury (TBI). The purpose of this study was to analyze whether late or interrupted PTP increases the risk of venous thromboembolism (VTE) after TBI.

Methods: We retrospectively studied patients with blunt TBI and stable head computed tomography (CT) scans who were admitted to two Level I trauma centers. PTP use was analyzed as an independent risk factor for VTE using separate logistic regression models for each definition of PTP use: (1) administration of PTP; (2) timing of PTP (early [<72 hours] vs. late [≥72 hours]); and (3) continuous versus interrupted use of PTP.

Results: Four hundred eighty patients with TBI were identified. VTE occurred in 15 patients (3.13%). VTE developed in six patients despite early PTP (5.56%), four patients with late PTP (2.72%), and five with no PTP (2.22%). Neither administration of PTP nor timing of PTP was independent predictor of developing a VTE (PTP vs. none: odds ratio [OR]=0.36, p=0.18; early PTP vs. late PTP: OR=2.00, p=0.41). PTP was administered continuously in 188 patients (73.7%). Patients with interrupted PTP had a significant increased odds of developing VTE compared with patients with continuous PTP (OR=7.07, p=0.04). Walking before discharge significantly decreased the odds of developing a VTE (OR=0.19, p=0.02).

Conclusions: Interrupted administration of PTP in patients with TBI is associated with significantly increased risk of VTE. These findings underscore the importance of continuous PTP administration, and every effort should be made to avoid interruption if possible.