Abstract
Venous thromboembolism (VTE) remains a major source of morbidity and mortality in severely injured patients despite current methods of risk stratification and prophylaxis, suggesting incomplete understanding of VTE risk factors. Given the liver's role in coagulation, we hypothesized that liver injury (LI) is associated with increased rates of VTE in severely injured patients.BACKGROUNDVenous thromboembolism (VTE) remains a major source of morbidity and mortality in severely injured patients despite current methods of risk stratification and prophylaxis, suggesting incomplete understanding of VTE risk factors. Given the liver's role in coagulation, we hypothesized that liver injury (LI) is associated with increased rates of VTE in severely injured patients.The American College of Surgeons Trauma Quality Improvement Project database (TQIP) 2017-2021 was retrospectively reviewed for patients with a maximum abdominal Abbreviated Injury Score (AIS) ≥ 4 with or without LI. Transfers, burns, all deaths, and patients < 18 years of age were excluded. Logistic regression was performed to assess the independent effect of LI on development of pulmonary embolism (PE) and deep venous thrombosis (DVT) while controlling for potential confounding variables.STUDY DESIGNThe American College of Surgeons Trauma Quality Improvement Project database (TQIP) 2017-2021 was retrospectively reviewed for patients with a maximum abdominal Abbreviated Injury Score (AIS) ≥ 4 with or without LI. Transfers, burns, all deaths, and patients < 18 years of age were excluded. Logistic regression was performed to assess the independent effect of LI on development of pulmonary embolism (PE) and deep venous thrombosis (DVT) while controlling for potential confounding variables.In 44,506 patients, there were 1,736 (3.9%) 890 (2.0%), and 18,642 patients (41.9%) with DVT, PE, and LI, respectively. After controlling for potential confounders, LI was independently associated with PE (aOR 1.279 [95% CI 1.088-1.504]) but was not associated with DVT (aOR 1.011 [95% CI 0.897-1.140]).RESULTSIn 44,506 patients, there were 1,736 (3.9%) 890 (2.0%), and 18,642 patients (41.9%) with DVT, PE, and LI, respectively. After controlling for potential confounders, LI was independently associated with PE (aOR 1.279 [95% CI 1.088-1.504]) but was not associated with DVT (aOR 1.011 [95% CI 0.897-1.140]).In severely injured patients, LI is an independent predictor of PE, but not DVT, suggesting LI is the source of either emboli or a more complex locally prothrombotic focus leading to downstream thrombi in the lung without causing upstream systemic venous thrombi. Further work should focus on elucidation of mechanisms including the portal venous blood coagulation profile, endothelial injury in the liver, and the potential for stasis of venous blood traversing an injured liver as well as the role for including LI in VTE risk stratification.CONCLUSIONIn severely injured patients, LI is an independent predictor of PE, but not DVT, suggesting LI is the source of either emboli or a more complex locally prothrombotic focus leading to downstream thrombi in the lung without causing upstream systemic venous thrombi. Further work should focus on elucidation of mechanisms including the portal venous blood coagulation profile, endothelial injury in the liver, and the potential for stasis of venous blood traversing an injured liver as well as the role for including LI in VTE risk stratification.