Use and Removal of Inferior Vena Cava Filters in Patients With Acute Brain Injury

Background: Few data exist regarding the rate of inferior vena cava (IVC) filter retrieval among brain-injured patients. Methods: We conducted a retrospective cohort study using inpatient claims between 2009 and 2015 from a nationally representative 5% sample of Medicare beneficiaries. We included patients aged ≥65 years who were hospitalized with acute brain injury. The primary outcome was the retrieval of IVC filter at 12 months and the secondary outcomes were the association with 30-day mortality and 12-month freedom from pulmonary embolism (PE). We used Current Procedural Terminology codes to ascertain filter placement and retrieval and International Classification of Diseases, Ninth Revision, Clinical Modification codes to ascertain venous thromboembolism (VTE) diagnoses. We used standard descriptive statistics to calculate the crude rate of filter placement. We used Cox proportional hazards analysis to examine the association between IVC filter placement and mortality and the occurrence of PE after adjustment for demographics, comorbidities, and mechanical ventilation. We used Kaplan-Meier survival statistics to calculate cumulative rates of retrieval 12 months after filter placement. Results: Among 44 641 Medicare beneficiaries, 1068 (2.4%; 95% confidence interval [CI], 2.3%-2.5) received an IVC filter, of whom 452 (42.3%; 95% CI, 39.3%-45.3) had a diagnosis of VTE. After adjusting for demographics, comorbidities, and mechanical ventilation, filter placement was not associated with a reduced risk of mortality (hazard ratio [HR], 1.0; 95% CI, 0.8-1.3) regardless of documented VTE. The occurrence of pulmonary embolism at 12 months was associated with IVC filter placement (HR, 3.19; 95% CI, 1.3-3.3) in the most adjusted model. The cumulative rate of filter retrieval at 12 months was 4.4% (95% CI, 3.1%-6.1%); there was no significant difference in retrieval rates between those with and without VTE. Conclusions: In a large cohort of Medicare beneficiaries hospitalized with acute brain injury, IVC filter placement was uncommon, but once placed, very few filters were removed. IVC filter placement was not associated with a reduced risk of mortality and did not prevent future PE.