Money well spent? A cost and utilization analysis of prophylactic inferior vena cava filter placement in high-risk trauma patients.

Background: Inferior vena cava filters (IVCF) for venous thromboembolic prophylaxis in high-risk trauma patients is a controversial practice. Utilization of IVCF prophylaxis was evaluated at a level 1 trauma center. Daily cost of IVCF prophylaxis, time to IVCF, duration between IVCF and chemoprophylaxis, and number of patients needed to treat (NNT) to prevent pulmonary embolism (PE) was calculated.

Methods: A retrospective review of prophylactic IVCF over a 5-year period (2010-2014). Demographic, physiologic, injury, procedural, and outcome data were abstracted from the administrative trauma database. Medicare fees and days without chemoprophylaxis were used to determine daily IVCF cost. NNT was calculated using PE events in a cohort without IVCF.

Results: Over the 5-year period, 146 patients with mean age 56.3 y (SD ± 24.2), 67.8% male, underwent prophylactic IVCF. Predominant mechanisms of injuries were falls (45.9%) and motor vehicle accidents (20.5%) with median Injury Severity Score of 25 (intraquartile range [IQR] 16-29) and head Abbreviated Injury Score of 3 (IQR 3-5). Most common operative interventions required in 24.7% were orthopedic (25.3%) and neurosurgical (21.9%). Median time to IVCF was 78 h (IQR 48-144). Most common IVCF indications were closed head injury (48.6%) and spinal injuries (30.8%). Median time to administration of chemoprophylaxis was 96 h after IVCF (IQR 24-192) in 57.5%. Median IVCF cost was $759/d (IQR $361-$1897) compared with $4.32 for chemoprophylaxis. PE occurred in 0.26% without IVCF. PE did not occur with prophylactic IVCF. Estimated NNT was 379 (95% CI 265, 661).

Conclusions: Prophylactic IVCF placement is a costly practice with relatively low benefit. Anticipated time without chemoprophylaxis and patient criteria should be considered before routine IVCF placement.