Changing Trends in Inferior Vena Cava Filter Placement

Tahir E. Yunus, MD, General Surgery, Nabil Tariq, MD, Rose E. Callahan, O. W. Brown, MD, Phillip J. Bendick, PhD, Gerald B. Zelenock, MD and Charles J. Shanley, MD
William Beaumont Hospital, Royal Oak, MI

Objective: The significant increase in the number of Inferior Vena Cava (IVC) filters being placed led us to evaluate the changing trends in indications and providers for filter placement.
Methods: A review was done of all patients with IVC filter placement at two time-points; 76 patients in 1995 were compared with 474 patients in 2005. Demographic data, provider data, filter type and indications for placement were collected. Indications were stratified into absolute, relative and prophylactic based on published recommendations.
Results: There was a greater than six-fold increase in the number of IVC filters placed in 1995 vs 2005. Mean patient age was 66 years in 1995 and 69 years in 2005 (p = .183); in 1995 47% of patients were male vs 46% in 2005 (p = .850). In 1995, 59% of patients receiving filters had lower extremity deep venous thrombosis (DVT) only, 37% had pulmonary embolism (PE) and 4% had no venous thromboembolic (VTE) disease. In 2005, 62% had DVT only, 30% had PE and 8% had no VTE disease (p=.223). Filters placed by cardiologists decreased from 50% in 1995 to 29% in 2005; interventional radiologists placed 50% in 1995 and 47% in 2005. No filters were placed by surgeons in 1995; 24% were placed by vascular or trauma surgeons in 2005 (p < .001). In 1995, 74% of filters were placed by cardiologists for absolute indications, vs 46% in 2005 (p=.006); 69% of filters were placed by radiologists in 1995 for absolute indications, vs 60% in 2005 (p=.340). Vascular surgeons placed 68% and trauma surgeons 58% for absolute indications in 2005. The percentage of filters placed for prophylactic indications has increased from 4% in 1995 to 8% in 2005 (cardiology 2% to 9%, radiology 5% to 3%, vascular surgeons 8% in 2005 and trauma surgeons 31% in 2005). Patients having only infra-popliteal DVT receiving filters increased from 7% in 1995 to 17% in 2005 (p = .026). Cardiologists increased placement of filters in these patients from 4% in 1995 to 24% in 2005 (p = .003), radiologists increased from 11% to 17% (p = .408); whereas 11% of filters placed by trauma surgeons and 8% by vascular surgeons were in patients with infra-popliteal DVT only in 2005. There has been a significant shift to the recently available low profile filters (<7 Fr); use of the 12 Fr Greenfield filter has decreased from 83% of all filters placed in 1995 to 8% in 2005.
Conclusions: Vascular and trauma surgeons now place a significant number of IVC filters, a result of increased endovascular training in these specialties. They, along with radiologists, appear to utilize absolute indications for filter placement in the majority of cases. Newer low profile delivery systems and increased diagnosis of VTE disease in patients may be contributing to the significant increase in filter placement. A shift in indications for placement from absolute toward prophylaxis is evident over time and across providers, indicating the need for consensus development of appropriate criteria.