Association of Mechanism of Injury With Risk for Venous Thromboembolism After Trauma.

Importance: To date, no study has assessed whether the risk of venous thromboembolism (VTE) varies with blunt or penetrating trauma.

Objective: To test whether the mechanism of injury alters risk of VTE after trauma.

Design, Setting, and Participants: A retrospective database review was conducted of adults admitted to the intensive care unit of an American College of Surgeons-verified level I trauma center between August 1, 2011, and January 1, 2015, with blunt or penetrating injuries. Univariate and multivariable analyses identified independent predictors of VTE.

Main Outcomes and Measures: Differences in risk factors for VTE with blunt vs penetrating trauma.

Results: In 813 patients with blunt trauma (mean [SD] age, 47 [19] years) and 324 patients with penetrating trauma (mean [SD] age, 35 [15] years), the rate of VTE was 9.1% overall (104 of 1137) and similar between groups (blunt trauma, 9% [n = 73] vs penetrating trauma, 9.6% [n = 31]; P = .76). In the blunt trauma group, more patients with VTE than without VTE had abnormal coagulation results (49.3% vs 35.7%; P = .02), femoral catheters (9.6% vs 3.9%; P = .03), repair and/or ligation of vascular injury (15.1% vs 5.4%; P = .001), complex leg fractures (34.2% vs 18.5%; P = .001), Glasgow Coma Scale score less than 8 (31.5% vs 10.7%; P < .001), 4 or more transfusions (51.4% vs 17.6%; P < .001), operation time longer than 2 hours (35.6% vs 16.4%; P < .001), and pelvic fractures (43.8% vs 21.4%; P < .001); patients with VTE also had higher mean (SD) Greenfield Risk Assessment Profile scores (13 [6] vs 8 [4]; P ≤ .001). However, with multivariable analysis, only receiving 4 or more transfusions (odds ratio [OR], 3.47; 95% CI, 2.04-5.91), Glasgow Coma Scale score less than 8 (OR, 2.75; 95% CI, 1.53-4.94), and pelvic fracture (OR, 2.09; 95% CI, 1.23-3.55) predicted VTE, with an area under the receiver operator curve of 0.730. In the penetrating trauma group, more patients with VTE than without VTE had abnormal coagulation results (64.5% vs 44.4%; P = .03), femoral catheters (16.1% vs 5.5%; P = .02), repair and/or ligation of vascular injury (54.8% vs 25.3%; P < .001), 4 or more transfusions (74.2% vs 39.6%; P < .001), operation time longer than 2 hours (74.2% vs 50.5%; P = .01), Abbreviated Injury Score for the abdomen greater than 2 (64.5% vs 42.3%; P = .02), and were aged 40 to 59 years (41.9% vs 23.2%; P = .02); patients with VTE also had higher mean (SD) Greenfield Risk Assessment Profile scores (12 [4] vs 7 [4]; P < .001). However, with multivariable analysis, only repair and/or ligation of vascular injury (OR, 3.32; 95% CI, 1.37-8.03), Abbreviated Injury Score for the abdomen greater than 2 (OR, 2.77; 95% CI, 1.19-6.45), and age 40 to 59 years (OR, 2.69; 95% CI, 1.19-6.08) predicted VTE, with an area under the receiver operator curve of 0.760.

Conclusions and Relevance: Although rates of VTE are the same in patients who experienced blunt and penetrating trauma, the independent risk factors for VTE are different based on mechanism of injury. This finding should be a consideration when contemplating prophylactic treatment protocols.