Early lower extremity fracture fixation and the risk of early pulmonary embolus: filter before fixation?

Venous thromboembolism is a major cause of morbidity and mortality after injury. Prophylactic anticoagulation is often delayed as a result of injuries or required procedures. Those patients at highest risk in this early vulnerable window postinjury are not well characterized. We sought to determine those patients at highest risk for an early pulmonary embolism (PE) after injury.

A retrospective analysis using data derived from a large state wide trauma registry (1997-2007) was performed. Patients with a documented PE and time of occurrence were selected (n = 712). Patients with fat emboli and lower extremity vascular injuries were excluded. Patients with a PE within the first 72 hours of admission (EARLY, n = 122) were compared with those with DELAYED presentation. Kaplan-Meier survival analysis was used to characterize the timing of death between the two groups. Backward stepwise logistic regression was used to determine independent risk factors for EARLY PE relative to those with DELAYED PE.

EARLY and DELAYED groups were similar in age, gender, Glasgow Coma Scale, emergency department systolic blood pressure, and injury mechanism. The EARLY PE group had a lower Injury Severity Score but injuries more commonly included femur fracture. Kaplan-Meier analysis revealed that EARLY PE patients have a significantly higher risk of early mortality relative to DELAYED PE patients (p = 0.012). Regression analysis revealed that the only independent risk factor for EARLY PE was lower extremity/pelvic orthopedic fixation (<48 hours from injury). The risk of EARLY PE was more than threefold higher (odds ratios, 3.85; 95% CI, 1.9-7.6; p < 0.001) for those who underwent early lower extremity orthopedic fixation versus those who did not.

Early lower extremity/pelvis orthopedic fixation is the single independent predictor of EARLY PE in this patient cohort. Venous thromboembolism/PE prevention strategies should be made a priority in this group of patients, including early preoperative institution of anticoagulation prophylaxis. These results suggest that those with contraindications to early anticoagulation may benefit from insertion of retrievable inferior vena cava filters preoperatively.