Risk Factors for Venous Thromboembolism After Admission for Traumatic Subdural Hematoma at Level I Trauma Center: Large Single-Institution Series

Background: Traumatic subdural hematomas (tSDHs) have high morbidity and mortality and often require neurosurgical intervention. The risk of venous thromboembolism (VTE) after tSDH ranges from 1%-20%, yet a consensus chemoprophylaxis protocol does not exist. An increased understanding of VTE risk factors following tSDH may inform development of prophylaxis guidelines.

Methods: Retrospective analysis of a prospective, single-institution Level I trauma center database identified the incidence and risk factors for deep venous thrombosis (DVT) and pulmonary embolism (PE) in consecutive tSDH patients from 1990-2015. Univariate and multivariate analyses were used.

Results: Of 3024 tSDH patients, 682 (22.6%) required neurosurgical intervention in the form of an intracranial pressure monitor, external ventricular drain (EVD), or craniotomy/craniectomy. Overall, 129 (4.3%) and 20 (0.7%) patients were diagnosed with a DVT or PE. Risk factors for DVT included age =60 (odds ratio [OR]=1.5, P=0.039), preexisting endocrine disorder (OR=4.1, P=0.001), hospital length of stay =7 days (OR=4.7, P < 0.001), intensive care unit length of stay =7 days (OR=3.6, P < 0.001), and lower extremity fracture (OR=2.1, P=0.004); GCS >3 was associated with a reduced DVT risk (OR=0.6, P=0.020). Risk factors for PE included intensive care unit length of stay =7 days (OR=9.7, P < 0.001) and lower extremity fracture (OR=4.7, P=0.002). Neurosurgical intervention did not independently increase VTE risk but was associated with increased hospital length of stay (P < 0.001).

Conclusions: While overall VTE risk is low following tSDH, elderly patients and those with severe injuries requiring prolonged hospitalizations have increased thrombotic risk. Development of tiered VTE prophylaxis regimens based on early postinjury thrombotic risk profiles warrants future study.