When Is It Safe to Start Pharmacologic Venous Thromboembolism Prophylaxis After Pelvic Fractures? A Prospective Study From a Level I Trauma Center.

BACKGROUND: The ideal time for pharmacologic venous thromboembolism (VTE) prophylaxis initiation after pelvic fracture is controversial. This prospective study evaluated the safety and efficacy of early VTE prophylaxis after blunt pelvic trauma. METHODS: Patients presenting to our American College of Surgeons-verified level I trauma center (between December 1, 2016 and November 30, 2017) with blunt pelvic fracture were prospectively screened. Exclusion criteria were emergency department death, immediate operative intervention, transfers, home anticoagulation, pregnancy, and patients receiving no pharmacologic VTE prophylaxis during hospitalization. Patients were dichotomized into study groups based on VTE prophylaxis initiation time ≤48 h (early prophylaxis [EP]) versus >48 h (late prophylaxis [LP]) after emergency department arrival. Demographics, injury data, clinical data, VTE prophylaxis agent and initiation time, and outcomes were compared. RESULTS: After exclusions, 146 patients were identified: 74 (51%) patients in EP group and 72 (49%) patients in LP group. Pelvic fracture severity was comparable between groups (Abbreviated Injury Scale extremity score 2 [2-3] versus 2 [2-3]; P = 0.610). On univariate analysis, deep vein thrombosis rates were higher after LP (n = 5, 7% versus 0, 0%; P = 0.027). Pulmonary embolism rates were similar (n = 2, 3% versus n = 3, 4%; P = 1.000). No patient required delayed intervention for bleeding, and postprophylaxis blood transfusion was comparable between groups (P > 0.05). On multivariate analysis, timing of pharmacologic VTE prophylaxis initiation was not associated with VTE development (odds ratio, 0.647; P = 0.999). Pelvic angioembolization was independently associated with VTE (odds ratio, 1.296; P = 0.044). CONCLUSIONS: Early initiation of pharmacologic VTE prophylaxis after blunt pelvic fracture is safe. Although EP initiation did not reduce the rate of VTE, these data identify angioembolization as an independent risk factor for VTE. Patients with blunt pelvic fracture who undergo angioembolization may therefore represent a high-risk population who may especially benefit from EP.