Purpose: Despite guidelines recommending retrieval of most inferior vena cava filters (IVCFs), when no longer indicated, retrieval rates remain low. IVCFs are a common incidental finding on diagnostic imaging studies. We hypothesize that use of a standardized macro in the impression of diagnostic computed tomography (CT) reports reminding clinicians to consider consultation for filter removal (if clinically appropriate) is associated with improved IVCF retrieval rates.
Materials and Methods: A standardized IVCF macro was recently developed at our institution that radiologists can optionally include in the impression of diagnostic CT reports. The macro suggests that clinicians consider referral for IVCF retrieval if the filter is no longer indicated. We retrospectively reviewed all patients at our institution with an IVCF incidentally noted on CT from May 2018 to July 2019 with at least 30 days of imaging follow-up documenting the continued presence or removal of the filter. Patients were divided into two cohorts based on whether or not the macro was used. Filter retrieval rates were calculated for each group at 30, 90, 180, and 365 days from the time of CT using Kaplan-Meier analysis. Logrank test was used to compare the cohorts. Demographic data for each group (age, sex) and time since initial filter placement (if known) were also obtained.
Results: A total of 102 patients were included in the “macro” group and 117 in the “no-macro” group. Patients in the macro group were younger (mean age, 57.9 years vs 63.9 years; P = 0.006). There was no difference between the macro and no-macro groups in proportion of male patients (0.500 vs 0.487; P = 0.85) and proportion of patients with filter placed more than 1 year before study entry (0.559 vs 0.512; P = 0.496). Overall IVCF retrievals were 22 of 102 (21.6%) in the macro group and 16 of 117 (13.7%) in the no-macro group (2 = 2.37; P = 0.124) with median post-CT removal times of 110.5 days and 81 days, respectively. Kaplan-Meier retrieval rates at 30, 90, 180, and 365 days were 4.9%, 10.2%, 16.4%, and 35.2%, respectively, in the macro group and 3.4%, 8.5%, 11.1%, and 21.1%, respectively, in the no-macro group (logrank P = 0.07).
Conclusions: Use of an IVCF macro in the impression of CT reports was associated with a trend toward improved IVCF retrieval rates at 1 year that did not reach statistical significance.