Prophylactic and therapeutic inferior vena cava filters to prevent pulmonary emboli in trauma patients

Hypothesis: Insertion of inferior vena cava filters (IVCFs) can prophylactically reduce pulmonary embolism (PE) in trauma patients. Design: Retrospective review. Setting: Urban, level I trauma center. Patients: Two hundred blunt trauma patients undergoing IVCF placement. Interventions: In 122 patients who had already been diagnosed as having deep vein thrombosis (DVT) (112 patients) and/or PE (22 patients), the insertion of the IVCF was considered "therapeutic." In 78 patients who had no evidence of DVT or PE but who were considered to be at high risk for a PE, the IVCF was considered "prophylactic." Main Outcome Measures: Incidence of PE and related mortality and morbidity in therapeutic VS prophylactic IVCFs. Results: The number of prophylactic IVCFs inserted increased significantly from only 4% (3/68 cases) from 1991 through 1996, up to 57% (75/132 cases) from 1997 to June 2001. Although the mean +/- SD age (5 +/- 20 years vs 41 +/- 15 years P<.001) was higher in the therapeutic group, there was no difference in the mean +/- SD Injury Severity Scores (20 12 vs 21 11). Therapeutic filters were placed much later after injury (mean SD time, 11 +/- 7 vs 3 2 days P<.001). The mortality rate was 11% (13/122 patients) in patients having a therapeutic IVCF, as compared with only 3% (2/78 patients) in those placed prophylactically (P=.07). None of the patients who had placement of a prophylactic IVCF developed subsequent PE. The incidence of PE decreased in all blunt trauma patients from 0.29% before 1997 to 0.15% afterjanuary 1, 1997, when 57% of the IVCF inserted were prophylactic (P=.06). Conclusions: Prophylactic IVCFs should be inserted within 48 hours of injury in specific trauma patients at high risk for PE and with contraindications to anticoagulation.