Yesterday, I reviewed a paper that highlighted a single-institution experience for IVC filter usage. Today, let’s look at a much larger pool of data.
Placement of a filter in the inferior vena cava (IVC) is one of the many tools for managing pulmonary embolism. There was a significant increase in filter placement during the 1990s and 2000s due to a broadening of the indications for its use. There has been continuing debate over the complications and efficacy of use of this device.
A paper from NYU Langone Health in New York City, the Harvey L. Neiman Health Policy Institute, and Georgia Institute of Technology School of Economics looked a long-term trends in IVC filter use in the Medicare population. They scanned a Centers for Medicare and Medicaid Services (CMS) database over the 22 year period from 1994 to 2015. They specifically analyzed trends in insertion, removal, placement setting, and specialty of the inserting physician.
Here are the factoids:
- 2008 seemed to be the heyday of IVC filter insertion. Rates nearly tripled by 2008, but have declined about 40% since then (see below). Pay attention to the retrieval rates.
- Overall, filters were most commonly placed by radiologists, followed by surgeons and cardiologists. Here’s the diagram above broken down by specialty.
- This chart shows the market share of each specialists inserting IVC filters during the study period. Of note, radiologists continue to increase and surgeons are decreasing.
Bottom line: This study shows some interesting data, but can’t be completely applied to trauma patients because it focuses on Medicare recipients. But the trends are valid. IVC filter use peaked in 2008 and has been declining ever since. Radiologists place more filters than other specialties, and their market share continues to increase.
Most disturbing is the low filter retrieval rate, similar to what was seen in yesterday’s post. Device manufacturers recommend removal of most filters, but timeframes are not specified. The real bottom line is that we have an indwelling device which works well in very limited situations only, can cause long term complications, and that we frequently forget to remove. It behooves all trauma professionals to develop strict guidelines for both use and removal.
Reference: National Trends in Inferior Vena Cava Filter Placement and Retrieval Procedures in the Medicare Population Over Two Decades. J Am Coll Radiol 15:1080-1086, 2018.
IVC filter insertion has been one of our tools for preventing pulmonary embolism for decades. Or so we thought. Its popularity has swung back and forth over the years, and has been in the waning stage now quite some time. This pendulum like motion offers an opportunity to study effectiveness when coupled with some of the large datasets that are now available to us.
IVC filters have been used in two ways: prophylactically in patients at high risk for pulmonary embolism (PE) who cannot be anticoagulated for some reason, and therapeutically once a patient has already suffered one. Over the years, guidelines have changed, and have frequently been in conflict. Currently, the American College of Chest Physicians does not recommend IVC filters in trauma patients, while the Eastern Association for the Surgery of Trauma promote their use in certain subsets.
A Pennsylvania group performed a large, retrospective review of three databases, the Pennsylvania Trauma Outcome Study (462K patients), the National Trauma Data Bank (5.8M patients), and the National Inpatient Sample. All were patients with an emergent trauma-related admission.
Here are the most interesting factoids:
- About 2% of all patients underwent IVC filter insertion, and 94% were inserted prophylactically
- About 90% of patients with a prophylactic filter had at least one predictor for PE, which means that the remaining 10% had none (!)
- Conversely, about 86% of patients who developed a PE had at least one risk factor, meaning that 14% had no recognized risk factors (!!)
- The use of IVC filters peaked in 2006-2008 at 2-4%, then falling steadily over the following 5-7 years to less than 1%
- PE rates peaked in 2008, then declined by 30% in the PTOS sample and stayed steady in the NTDB
Bottom line: The use of IVC filters peaked in 2008 and has been in decline since then. But interestingly, the rates of PE and fatal PE have been steady to declining, depending on the data set. Obviously, there are always some shortcomings for studies like this. Remember, IVC filters are intended to prevent fatal PE. It is possible that some fatal PEs were not identified in these databases. Furthermore, it was not possible to obtain any information on the use of chemical prophylaxis in these patients.
Overall, there has been no increase in PE and fatal PE rates over the time period that IVC filter usage has been decreasing. This suggests that these devices have not had their intended effect. Trauma professionals need to very seriously consider the specific indications in any patient they are considering for insertion. They may not have the protective effect you think.
Reference: Vena Cava Filter Use in Trauma and Rates of Pulmonary Embolism, 2003-2015. JAMA Surg 152(8):724-732, 2017.