Orthopedic trauma results in systemic physiologic changes that predispose patients to venous thromboembolism (VTE). In the absence of prophylaxis, VTE incidence may be as high as 60%. Mechanical and pharmacologic thromboprophylaxis are effective in decreasing rates of VTE. Combined mechanical and pharmacologic thromboprophylaxis is more efficacious for decreasing VTE incidence than either regimen independently. If pharmacologic thromboprophylaxis is contraindicated, mechanical prophylaxis should be used. Patients with isolated lower extremity fractures who are ambulatory, or those with isolated upper extremity trauma, do not require pharmacologic prophylaxis in the absence of other VTE risk factors.
Key points
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Traumatic musculoskeletal injury results in systemic physiologic changes that predispose patients to venous thromboembolism (VTE).
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Combined mechanical and pharmacologic thromboprophylaxis is most efficacious for decreasing VTE incidence.
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Low molecular weight heparin is the preferred agent for pharmacologic thromboprophylaxis.
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Pharmacologic prophylaxis should be initiated as soon as possible, and should be continue for a minimum of 14 days.
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Patients with isolated lower extremity fractures who are ambulatory do not require pharmacologic prophylaxis in the absence of other VTE risk factors.
Physiology and epidemiology of venous thromboembolism in trauma
Basic Science and Physiology of Trauma and Coagulation
Traumatic injury results in significant physiologic changes. Serum levels of inflammatory cytokines including interleukin-6 (IL-6), IL-8, and tumor necrosis factor-alpha (TNF-α) are increased following traumatic injury and result in a hypercoagulable state. In addition to inflammatory markers, serum levels and activity of procoagulant microparticles are significantly increased following blunt trauma, and peak thrombin levels are correlated to injury severity. The systemic inflammatory response triggered by traumatic injury results in a hypercoagulable state that places patients at increased risk of venous thromboembolism (VTE). This hypercoagulability combined with endothelial injury and venous stasis, 2 other conditions often noted in trauma patients, completes the Virchow Triad. The presence of all 3 elements contributes to venous thrombosis.
Venous Thromboembolism Following Major Trauma
Before the implementation of routine thromboprophylaxis, reported rates of VTE following major trauma were extremely high. Using bilateral lower extremity venography, Geerts and colleagues reported a 58% incidence of lower extremity deep vein thrombosis (DVT) in 349 patients admitted for major traumatic injuries who did not receive thromboprophylaxis. DVT rates varied by anatomic region injured, ranging from 50% in patients with major injuries to the face, chest, or abdomen to 80% in patients with femur fractures. The rate of fatal pulmonary embolism (PE) was 0.9%, and independent risk factors for DVT identified included age, blood transfusion, surgery, fracture of the femur or tibia, and spinal cord injury. Despite its relatively low incidence, PE is still the third most common cause of in-hospital death among trauma patients.
Thromboprophylaxis for Venous Thromboembolism in Trauma Patients
Both chemical and mechanical thromboprophylaxis has been shown to decrease rates of VTE in the setting of trauma. Pharmacologic prophylaxis with low molecular weight heparin (LMWH) was shown to significantly decrease the incidence of both DVT and PE in a large cohort of more than 2200 trauma patients. Mechanical prophylaxis with pneumatic sequential compression devices (SCDs) significantly decreased VTE incidence from 11% to 4% ( P = .02) in a prospective randomized controlled trial of 300 orthopedic trauma patients compared with no VTE prophylaxis. A growing understanding of the importance of thromboprophylaxis in trauma patients has led to the development of institutional protocols for VTE prophylaxis at trauma centers around the world. Additionally, several professional organizations have published clinical guidelines for thromboprophylaxis in trauma patients, which are summarized in Table 1 .
Organization | Summary of Findings and Recommendations |
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Cochrane database systematic review |
|
American College of Chest Physicians (ACCP) |
|
Eastern Association for the Surgery of Trauma (EAST) |
|
Orthopedic Trauma Association (OTA) |
|
|
More recent literature using larger patient cohorts and routine thromboprophylaxis protocols has better defined the true incidence of clinically relevant VTE following severe trauma. A retrospective review of a multicenter trauma registry containing nearly 8000 major trauma patients identified a VTE incidence of only 1.8% when institutional thromboprophylaxis protocols were used. Despite the relatively low incidence, the presence of VTE (either DVT or PE) nearly doubled the mortality rate (13.7% vs 7.4%), and among patients who developed a PE, the mortality rate was 25.7%. A single-center retrospective review of more than 1300 major trauma patients treated at a level 1 trauma center revealed a 2.3% incidence of PE. All PEs occurred within 15 days of injury, with most being diagnosed within the first week. Age older than 55 years, multisystem injury, cannulation of central veins, and pelvic fractures (but not long-bone fractures) were independent risk factors for developing a PE. Using a statewide trauma database over a 5-year period, Tuttle-Newhall and colleagues reported an overall PE incidence of 0.3% among more than 300,000 trauma patients receiving standard VTE prophylaxis. Age older than 55 was a significant risk factor for development of PE, with an incidence of 0.7% in this demographic. Increasing Injury Severity Score (ISS) and Abbreviated Injury Scale (AIS) for the extremities, soft tissue, and chest regions were also associated with significantly increased risk of PE.
Physiology and epidemiology of venous thromboembolism in trauma
Basic Science and Physiology of Trauma and Coagulation
Traumatic injury results in significant physiologic changes. Serum levels of inflammatory cytokines including interleukin-6 (IL-6), IL-8, and tumor necrosis factor-alpha (TNF-α) are increased following traumatic injury and result in a hypercoagulable state. In addition to inflammatory markers, serum levels and activity of procoagulant microparticles are significantly increased following blunt trauma, and peak thrombin levels are correlated to injury severity. The systemic inflammatory response triggered by traumatic injury results in a hypercoagulable state that places patients at increased risk of venous thromboembolism (VTE). This hypercoagulability combined with endothelial injury and venous stasis, 2 other conditions often noted in trauma patients, completes the Virchow Triad. The presence of all 3 elements contributes to venous thrombosis.
Venous Thromboembolism Following Major Trauma
Before the implementation of routine thromboprophylaxis, reported rates of VTE following major trauma were extremely high. Using bilateral lower extremity venography, Geerts and colleagues reported a 58% incidence of lower extremity deep vein thrombosis (DVT) in 349 patients admitted for major traumatic injuries who did not receive thromboprophylaxis. DVT rates varied by anatomic region injured, ranging from 50% in patients with major injuries to the face, chest, or abdomen to 80% in patients with femur fractures. The rate of fatal pulmonary embolism (PE) was 0.9%, and independent risk factors for DVT identified included age, blood transfusion, surgery, fracture of the femur or tibia, and spinal cord injury. Despite its relatively low incidence, PE is still the third most common cause of in-hospital death among trauma patients.
Thromboprophylaxis for Venous Thromboembolism in Trauma Patients
Both chemical and mechanical thromboprophylaxis has been shown to decrease rates of VTE in the setting of trauma. Pharmacologic prophylaxis with low molecular weight heparin (LMWH) was shown to significantly decrease the incidence of both DVT and PE in a large cohort of more than 2200 trauma patients. Mechanical prophylaxis with pneumatic sequential compression devices (SCDs) significantly decreased VTE incidence from 11% to 4% ( P = .02) in a prospective randomized controlled trial of 300 orthopedic trauma patients compared with no VTE prophylaxis. A growing understanding of the importance of thromboprophylaxis in trauma patients has led to the development of institutional protocols for VTE prophylaxis at trauma centers around the world. Additionally, several professional organizations have published clinical guidelines for thromboprophylaxis in trauma patients, which are summarized in Table 1 .
Organization | Summary of Findings and Recommendations |
---|---|
Cochrane database systematic review |
|
American College of Chest Physicians (ACCP) |
|
Eastern Association for the Surgery of Trauma (EAST) |
|
Orthopedic Trauma Association (OTA) |
|
|