What is an IVC Filter?
An inferior vena cava (IVC) filter is a tiny, umbrella-shaped device that is implanted inside the large veins (called the inferior vena cavas) that takes blood from the lower part of the body back to the heart. IVC filters can help prevent pulmonary embolism (PE) by catching blood clots before they reach the lungs.
Types of IVC Filters
There are different types of IVC filters that are designed to be implanted either permanently or temporarily. Some of the common types include:
- Permanent IVC filters: Made of metal and designed to stay in place permanently. They are embedded into the wall of the vein. Examples include the Gunther Tulip and Bard Recovery
Inferior Vena Cava (IVC) Filter.
- Retrievable IVC filters: Made of either metal or plastic and designed to remain in place temporarily for a defined period of time. These can potentially be removed by a specialized catheter once the risk of PE has passed. Examples include the OptEase, Denali, and Option ELITE filters.
- Inferior vena cava umbrella filters: The oldest type of filter consisting of legs protruding into the vessel that act as struts to capture passing blood clots.
How Are IVC Filters Placed?
IVC filters are usually implanted by an interventional radiologist in a minimally invasive procedure using imaging guidance like fluoroscopy or ultrasound. The placement involves:
- Making a small incision in the leg or neck and inserting a catheter into the large vein.
- Using the catheter to advance the collapsed filter through the vein towards the IVC above the level where it joins the renal veins.
- Deploying the filter arms by withdrawing the catheter sheath, allowing the arms to spring open inside the IVC with the legs pointing downstream to catch any clots.
- Placement is confirmed with imaging to ensure the filter is in the correct position and any potential complications evaluated. Theprocedure itself usually takes 30-60 minutes.
Who Needs an IVC Filter?
IVC filters may be recommended by doctors in certain high-risk situations to prevent pulmonary embolism, including:
- When anticoagulation or blood thinners like warfarin cannot be used due to risk of bleeding complications.
- When blood clots have developed in the legs or pelvis despite anticoagulant treatment (called failing anticoagulation).
- Prior to high-risk surgery when the risk of venous thromboembolism is significant.
- When there is a documented PE alongside deep vein thrombosis in the legs despite anticoagulation.
- During pregnancy when anticoagulants pose a risk to the fetus.
Benefits and Risks of IVC Filters
IVC filters have proven effective in many cases at stopping large blood clots from traveling to the lungs and preventing PE when alternatives aren't an option. However, they also carry some risks, including:
- Filter migration: There is a small chance the filter may slowly move from its original implant site, which could allow clots to pass or cause other complications.
- Penetration of filter legs: In rare cases, the legs of the filter may puncture or penetrate the wall of the IVC which carries risks of leaks, bleeding or organ damage.
- Recurrent DVT/PE: The filter does not prevent new clots from forming in the legs which could still travel to the lungs despite the filter.
- Snagging and fracture: There have been cases of the filter legs snagging or shearing off pieces which may cause injury. This is more common with metal or hybrid filters.
- Difficulty with retrieval: Not all retrievable filters can be successfully taken out, with reported retrieval failure rates of 5-10%.
Overall, IVC filters have successfully prevented hundreds of thousands of PEs in high-risk patients. However, ongoing monitoring and eventual retrieval is crucial to weigh risks versus benefits over time.
Long-Term Management of IVC Filters
Patients with implanted IVC filters require lifelong monitoring by a specialist, which involves:
- Serial imaging checks (e.g. CT scans) at 1, 6, 12 months, and annually after placement to assess filter position, integrity and for signs of DVT.
- Consideration for retrieval if the temporary filter is no longer needed based on risk changing or complications. Removal of unnecessary filters avoids long-term risks.
- Continued anticoagulation medication unless contraindicated to help prevent new clot formation in the legs.
- Close follow up if a new DVT develops to determine if filter thromboses or needs to be retrieved.
- Specialized endovascular techniques may be used in attempts to remove embedded, misplaced, complicated or fractured filters. But not all can be removed.
Complications of Leaving Filters for Prolonged Periods
Research has shown certain long-term complications linked to leaving IVC filters implanted for extended durations:
- Strut fractures or fatigue - Metal struts are prone to fracture or break after 4-10 years of placement leading to fragment embolization.
- Filter migration - Up to 50% of filters migrate partially or completely over time which reduces effectiveness.
- IVC thrombosis - Leaving filters in indefinitely may irritate the vein wall leading to scar tissue, webbing, and eventually blockage.
Get this Report in Japanese Language:
Get this Report in Korean Language:
About Author:
Vaagisha brings over three years of expertise as a content editor in the market research domain. Originally a creative writer, she discovered her passion for editing, combining her flair for writing with a meticulous eye for detail. Her ability to craft and refine compelling content makes her an invaluable asset in delivering polished and engaging write-ups.
(LinkedIn: https://www.linkedin.com/in/vaagisha-singh-8080b91)
Comments
0 comment