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Patient Evidence Summary
Doctor, I am at risk of blood clots travelling to my lungs. Should I agree to insertion of a filter to protect me?
In people at risk of having a DVT travel from their leg to their lungs (PE), there are very few studies assessing the use of an inferior vena cava filter (IVCF) to prevent PE or death. Overall, it appears that these filters can reduce the risk of blood clots reaching the lungs. However, inserting these filters into a large vein in the pelvis can lead to a higher risk of developing a new DVT in the legs, and they do not decrease the risk of death compared to not inserting a filter.
Study highlights
People with an IVCF were less likely to have a new or recurrent PE. However, they were more likely to develop new DVT.
Insertion of an IVCF did not reduce the risk of death due to PE or death from any cause compared with no filter use.
Understanding the problem
The first-choice treatment for venous thromboembolism is anticoagulants, which prevent blood clots from becoming larger or travelling from the leg to the lungs (PE) and new clots from forming (recurrent VTE). Because some people cannot take anticoagulants or are at high risk of developing a new or recurrent PE, IVCFs have been used for many years as an alternative treatment option or in addition to anticoagulants.
IVCFs are inserted through the skin at the groin or neck and placed into the largest vein of the pelvis, which carries blood from the lower body back to the heart. They have an umbrella-like form and allow blood to pass but are designed to catch medium- or large-sized blood clots. Unlike anticoagulants, IVCFs do not increase the risk of bleeding, and they can be used during surgery. Most of the filters used nowadays can be removed once they are no longer needed. However, complications can occur, such as insertion problems; broken filters (with pieces later travelling to other body parts), or blockage of the filter by blood clots. Also, the longer filters are left in place, the more likely they will become attached to the vein wall, making retrieval difficult or impossible.
Although IVCFs are widely used, particularly in the U.S., only a few studies have actually evaluated the benefits and risks of IVCF use compared to no filter use. Therefore, expert recommendations are not consistent.
The aim of this article was to report the results of a systematic review and meta-analysis that identified and combined published studies assessing the risks and benefits of IVCFs in people at risk of developing PE.
A summary of 11 studies published up to October 2016.
Who? The studies included 4204 people who were at risk of developing PE for various reasons. The study group received an IVCF, and the control group received usual care without an IVCF. Studies were included if patients entered the study before or at the time of the IVCF insertion.
What? The studies compared IVCF use with no IVCF use.
IVCF | vs | No IVCF |
|---|---|---|
Insertion of a retrievable or permanent IVCF. Reasons for IVCF insertion as well as the remainder of the treatment were defined by the study design or the treating physicians and varied between studies. | Usual care, including anticoagulants and/or supportive measures. Usual care was defined by the study design or the treating physicians and varied between studies. |
IVCF use vs no IVCF use in people who are at risk for PE for various reasons
Outcomes | Rate of events with IVCF | Rate of events without IVCF | Results | Number of studies and quality of the evidence |
|---|---|---|---|---|
PE | 2 out of 100 people | 5 out of 100 people | About 3 fewer people out of 100 had a PE after insertion of an IVCF | 11 studies low-quality of evidence |
Death due to PE | 1 out of 100 people | 2 out of 100 people | No difference* | 11 studies low-quality of evidence |
| Death due to any cause | 8 out of 100 people | 9 out of 100 people | No difference* | 10 studies low-quality of evidence |
| DVT | 5 out of 100 people | 3 out of 100 people | About 2 more people out of 100 had a DVT after insertion of an IVCF | 10 studies moderate-quality of evidence |
*Although the rates for the 2 groups look different, the differences were not statistically significant—this means that the difference could simply be due to chance rather than due to the different treatments.
This Evidence Summary is based on the following article:
Bikdeli B, Chatterjee S, Desai NR, et al. Inferior Vena Cava Filters to Prevent Pulmonary Embolism: Systematic Review and Meta-Analysis. J Am Coll Cardiol. 2017 Sep 26;70(13):1587-1597. doi: 10.1016/j.jacc.2017.07.775. PubMed
Tobias Tritschler, MD
Dr. Tritschler is a Swiss General Internal Medicine physician currently enrolled in the Adult Thrombosis Medicine fellowship and the Master of Science in Epidemiology programs at the University of Ottawa. He is funded by CanVECTOR, the Department of Medicine at the University of Ottawa, and the Swiss National Science Foundation. His research interests include prevention of venous thromboembolism and standardization of outcome definitions in thrombosis research.
Lori-Ann Linkins, MD, MSc (Clin Epi), FRCPC
Dr. Linkins is an Associate Professor of Medicine (thrombosis) at McMaster University in Hamilton, Canada. She holds a Masters Degree in Health Research Methodology and is a Deputy Editor with the Health Information Research Unit, McMaster. Her research interests include heparin-induced thrombocytopenia and cancer-associated thrombosis. She was editor of the ACCP Guidelines, 9th Edition HIT chapter and is currently a member of the ASH VTE Guidelines HIT Panel.
Published: Monday, August 19, 2019
Last Updated: Thursday, July 30, 2020
Please note that the information contained herein is not to be interpreted as an alternative to medical advice from a professional healthcare provider. If you have any questions about any medical matter, you should consult your professional healthcare providers, and should never delay seeking medical advice, disregard medical advice or discontinue medication based on information provided here.
, McMaster University