Optimal Timing of Initiation of Thromboprophylaxis after Nonoperative Blunt Spinal Trauma: A Propensity-Matched Analysis

Background: Patients with spinal trauma have the highest risk of a venous thromboembolism. Although anticoagulation is recommended, its optimal timing is not well-defined. We aimed to assess the impact of early initiation of thromboprophylaxis in spinal trauma patients who were managed nonoperatively. Study Design: A 2-year (2013 to 2014) analysis of all isolated spinal trauma patients managed nonoperatively who received thromboprophylaxis in the American College of Surgeons Trauma Quality Improvement Program. Patients were divided into 2 groups based on timing of initiation of thromboprophylaxis: early (<48 hours) and late (≥48 hours), and were matched in a 1:1 ratio using propensity score matching for demographic characteristics, admission vitals, injury severity, level of spine injury, and type of prophylaxis. Outcomes were prevalence of deep venous thrombosis (DVT) and pulmonary embolism, packed RBC requirement, and mortality. Results: We included 20,106 patients, of which 8,552 (early, n = 4,276; late, n = 4,276) were matched. Matched groups were similar in demographic characteristics, vital and injury parameters, and type of prophylaxis. Patients in the early group were less likely to have DVT (1.7% vs 7.6%; p < 0.001) or pulmonary embolism (0.8% vs 2.2%; p < 0.001) develop compared with the late group. In addition, there was no difference in packed RBC requirement (p = 0.61) and mortality (p = 0.49). Patients who received unfractionated heparin had a similar rate of DVT (p = 0.26) and pulmonary embolism (p = 0.35) compared with those who received low-molecular-weight heparin. Conclusions: In patients with nonoperative spinal trauma, early initiation of thromboprophylaxis is associated with decreased rates of DVT and pulmonary embolism. In addition, we did not find any association between the type of pharmacologic agents and venous thromboembolism rates. Additional prospective clinical trials should be undertaken to define guidelines for the timing of initiation of thromboprophylaxis.