A pilot study on the randomization of inferior vena cava filter placement for venous thromboembolism prophylaxis in high-risk trauma patients

Background: Placement of prophylactic inferior vena cava filters (pIVCFs) for the prevention of pulmonary embolism (PE) in high-risk trauma patients (HRTPs) are widely practiced despite the lack of Level I data supporting this use. We report the 2-year interim analysis of the Filters in Trauma pilot study. Methods: This is a single institution, prospective randomized controlled pilot feasibility study in a Level I trauma center. HRTPs were identified for pIVCF placement by the Eastern Association for the Surgery of Trauma guidelines. From November 2008 to November 2010, HRTPs were enrolled and randomized to either pIVCF or no pIVCF. All patients received pharmacologic prophylaxis when safe. Primary outcomes included feasibility objectives and secondary outcomes were incidence of PE, deep vein thrombosis (DVT), and death. Results: Thirty-four of 38 enrolled patients were eligible for analysis. The baseline sociodemographic characteristics were balanced between the both groups. Results of the feasibility objectives included: time from admission to enrollment (mean, 47.4 hours ± 22.0 hours), time from enrollment to randomization (mean, 4.8 hours ± 9.1 hours), time from randomization to IVCF placement (mean, 16.9 hours ± 9.2 hours), adherence to weekly compression ultrasound within first month (IVCF group = 44.4%; non-IVCF group = 62.5%), and 1-month clinical follow-up (IVCF group = 83.3%; non-IVCF group = 100%). At 6-month follow-up, one PE in the nonfilter group and one DVT in the filter group had occurred. One non-PE-related death occurred in the filter group. Barriers to enrollment included inability to obtain informed consent due to patient refusal or no next of kin identified and delayed notification of eligibility status. Conclusion: Our pilot study demonstrates for the first time that a randomized controlled trial evaluating the efficacy of pIVCFs in trauma patients is feasible. This pilot data will be used to inform the design of a multicenter randomized controlled trial to determine the incidence of PE and DVT in HRTPs receiving pIVCFs versus no pIVCF.