IVC filters are small, cage-like devices that are inserted into the inferior vena cava (the main vessel returning
blood from the lower half of the body to the heart) to capture blood clots and prevent them from reaching the lungs.
Types of IVC Filters
- Temporary IVC Filter
- Permanent IVC Filter
Temporary IVC Filter
- Celect IVC Filter
This is a newer design that is based on the Gunther Tulip filter and designed to be more easily retrievable.
It is made of Chronic which is a cobalt- chromium-nickel-molybdenum-iron alloy. It has a single-cone design
and incorporates secondary struts, designed to center re the filter at deployment and throughout its duration of use.
- Gunther Tulip Filter
The predecessor to the Celect, it was approved for use in Europe in 1992. It consists of 4 legs, each 44mm in length,
and has 12 filter wires in total. It is also made of Conichrome® and has similar insertion requirements to the Celect.
No limit on the retrieval window has been set. A retrieval success rate of 94% at 12 weeks was identified in a recent study
- G2/Denal Filter
This nitinol (nickel-titanium alloy) filter has a conical shape with 6 legs and 6 filter wires arranged in 2 offset layers.
It has elastic fixation hooks designed to allow easier removal. Maximum caval diameter for insertion is 28mm and it requires a 7F sheath. One study found a 95% retrieval success rate, with median indwell time of 144 days and the longest indwell time of 300 days. FDA approved for permanent use in 2005 and for retrievable use in 2008.
- OptEase Filter
This nitinol hypotube filter is a modified version of the permanent TrapEase filter. It has a double-basket design for dual-level filtration and has side struts with unidirectional fixation barbs to protect against cephalad migration. It can be inserted via jugular, femoral or antecubital approaches but has a hook at the caudal end only and therefore may be retrieved only by a femoral approach. However this can be useful where the jugular veins are thrombosed. Maximum caval diameter for insertion is 30mm. It requires a relatively small 6F introducer system. A 2009 study found a retrieval success rate of 93% but with a mean interval of 11 days. Some studies have suggested a higher rate of IVC thrombosis due to the double-basket design; overall rates range from 0 to 12.5%. The retrieval window as indicated by the manufacturer is relatively short at 23 days. FDA approved for permanent use in 2002 and retrievable use in 2004.
- ALN filter
This filter is made from 316L stainless steel alloy that is nonferromagnetic and is MR compatible. It has a dual level arrangement with 6 short hooked legs to ensure fixation to the caval wall and 3 longer legs for centering. There is no recommendation from the manufacturer regarding retrieval window; the longest documented retrieval interval is 25 months. A 2008 study recorded a retrieval success rate of 99% after a mean interval of 93 days. FDA approved for permanent and retrievable use in 2008. CE marked.
- Option Filter
This is a newer design, laser cut from a single piece of nitinol for greater strength. It has a conical shape with
6 struts and a caudal hook. It is inserted via a 5F system, the smallest on the market. Maximum caval diameter is 32mm. A 2010 study recorded a retrieval success rate of 92% with mean interval of 67 days.
- Crux filter
This has a novel design with two nitinol spiral elements crimped at the ends to form a symmetric double-looped helical structure. A filter mesh designed to capture clots is attached to one loop. Three fixation anchors are crimped to the opposite loop, two of which are located at the loop midpoints and the third at the tail end. Each end has a retrieval element for capture by a snare via jugular or femoral access. The symmetrical design is intended to self-center re the filter.
- Titanium Greenfield Filter
This is a conical filter descended from the original Kimray-Greenfield filter. It has 6 struts, each with a curved hook. It is made of beta III titanium alloy with elastic properties but still requires a relatively large 12F system for insertion. Initial studies identified an unacceptable 30% rate of tilting, penetration and migration. This led to a modification of the hooks to reduce penetration. There are good long- term patency rates with low rates of thrombosis. The Greenfield designs are regarded as the standard IVC filters because of their long track record. FDA approved in 1989. CE marked.
- TRAPEASE Filter
This has a similar design to the Opt Ease described above. One difference is the provision of proximal and distal hooks designed to prevent migration in either the caudal or cephalic directions.
- Gianturco-Roehm Bird’s Nest Filter
This has a unique design with two V-shaped struts supporting a random tangle of very fine wires. This is the only filter that can be used in megacavas (up to 40mm diameter).
- Simon Nitinol Filter
The Simon Nitinol Filter is indicated for use in the prevention of recurrent pulmonary embolism via placement in the vena cava in the following situations:
- Pulmonary thromboembolism when anticoagulants are contraindicated
- Failure of anticoagulant therapy in thromboembolic disease
- Emergency treatment following massive pulmonary embolism where anticipated benefits of conventional therapy are reduced
- Chronic, recurrent pulmonary embolism where anticoagulant therapy has failed or is contraindicated.