Background
After traumatic spinal cord injury (SCI), there is increased risk of venous thromboembolism (VTE), but chemoprophylaxis (PPX) may cause expansion of intraspinal hematoma (ISH).
Methods
Single-center retrospective study of adult trauma patients from 2012–2015 with SCI. Exclusion criteria: VTE diagnosis, death, or discharge within 48 hours. Patients were dichotomized based on early (≤48 hours) heparinoid and/or aspirin PPX. ISH expansion was diagnosed intraoperatively or by follow-up radiology. We used multivariable Cox proportional hazards to estimate the effect of PPX on risk of VTE and ISH expansion controlling for age, ISS, complete SCI, and mechanism as static covariates and operative spine procedure as a time-varying covariate.
Results
501 patients with SCI were dichotomized into early PPX (n=260, 52%) and no early PPX (n=241, 48%). Early PPX patients were less likely blunt-injured (91% vs 97%) and had fewer operative spine interventions (65% vs 80%), but age (median 43 vs 49 years), ISS (median 24 vs 21), admission ISH (47% vs 44%), and VTE (5% vs 9%) were similar.
Cox analysis found that early heparinoids was associated with reduced VTE (HR 0.37, 95% CI 0.16–0.84) and reduced pulmonary embolism (PE) (HR 0.20, 95% CI 0.06–0.69). The estimated number needed to treat with heparinoids was 10 to prevent one VTE and 13 to prevent one PE at 30 days. Early aspirin was not associated with reduced VTE or PE. Seven patients (1%) had ISH expansion, of which 4 were on PPX at time of expansion. Using heparinoid and aspirin as time-varying covariates, neither heparinoids (HR 1.90, 95% CI 0.32–11.41) nor aspirin (HR 3.67, 95% CI 0.64–20.88) was associated with ISH expansion.
Conclusion
Early heparinoid therapy was associated with decreased VTE and PE risk in SCI patients without concomitant increase in ISH expansion.
Level of Evidence
Level IV (Therapeutic)