Differences in IVC Filters
Inferior vena cava filters vary both in the size of the veins in which they can be implanted and in the materials of which they are made.
Vena Cava Diameter
One of the main IVC filter differences is related to the diameter of the vena cava for which they can be used. The Bird’s Nest® Vena Cava filter, for example, can be used in a vena cava measuring up to 40 millimeters (mm) in diameter.Bard’s Denali filter is approved for inferior vena cava diameters less than or equal to 28 mm. The Cook Celect filter is designed for use in vena cavas with diameters less than 30 mm and more than 15 mm.
Most types of IVC filters are made of nonferromagnetic materials and are not affected by magnetic fields. This is important since it permits the use of magnetic resonance imaging (MRI) in patients who have been implanted with such filters.
Some types of IVC filters, however, are made of weakly ferromagnetic materials. These filters are classified as MR Conditional. MRI can generally be used with these IVC filters, but there are some restrictions. In some cases the use of MRI must be delayed to allow for the filter to become firmly attached to the vena cava wall so that it won’t move if exposed to the magnetic field. This is the case with the Cook Bird’s Nest filter. The Denali and Günther Tulip are also MR Conditional, but patients with these filters can be scanned immediately after filter placement if certain conditions are met.
IVC Filter Complications
In general, IVC filter complications appear to be much more common with retrievable filters than with permanent filters. Doctors at Chicago’s NorthShore University HealthSystem recently reviewed IVC filter placement in 1,225 patients who had received either permanent (785) or retrievable (449) filters. Retrievable filters used in this study were primarily the Cook Celect (241 patients), Cook Günther Tulip (54 patients), Bard G2X (84 patients) and Bard Recovery (39 patients). Patients with retrievable filters had significantly more complications overall than those with permanent filters. Device related complications (vena cava perforation, filter migration and filter fracture) were significantly more common with retrievable filters compared to permanent filters. The authors expressed the view that retrievable filters may have sacrificed long-term design integrity for the sake of ease of retrievability. They warned, “Long term use of retrievable filters should be avoided…” The results of the investigation were published in the Journal of Vascular Surgery: Venous and Lymphatic Disorders™ in 2014.
“With regard to retrievable ﬁlters, the design of the ﬁlter must be such that it allows the ﬁlter to be collapsed during retrieval like an umbrella, allowing it to be withdrawn through a vascular sheath. It is felt that this structural modiﬁcation, in comparison with permanent ﬁlter designs, is the engineering trade-off between long-term design integrity vs ease of retrievability.”
Tina R. Desai, MD, et al., “Complications of indwelling retrievable versus permanent inferior vena cava ﬁlters,” Journal of Vascular Surgery: Venous and Lymphatic Disorders, 2014.
Complications Associated With Particular IVC Filter Brands:
Celect IVC Filter and Günther Tulip IVC Filter
Both of these IVC filters have been associated with high rates of perforation of the inferior vena cava by the filter legs. This not only damages the IVC, but can damage organs outside the IVC, including the aorta, intestines, kidneys, pancreas and spinal column.
In one 2012 study of Celect and Günther Tulip filters, CT scans by doctors at the University of California revealed perforation of filter components through the wall of the IVC in 86% of patients. A study by doctors at Northwestern University also revealed significant rates of vena cava penetration associated with Cook’s Celect and Günther Tulip filters. Filter fracture, tilt and migration were also seen in the Cook filters.
Bard Retrievable IVC Filters
The Northwestern University study (mentioned above) investigated six different Bard IVC filters as well as the Cook filters and several other brands. The six Bard filters were the Recovery, G2, G2X, G2 Express, Eclipse and Meridian. Filter fracture and limb embolization (the movement of a fractured filter leg through the IVC to another location, such as the heart or lung) were both higher for the Bard filters than any of the other filters investigated. For more information on complications linked to this filter, visit the Bard IVC Filter page.
Optease IVC Filter
In May 2015, the journal Thrombosis Research published a study of 142 patients who experienced a major trauma (71 were involved in motor vehicle accidents) and were treated with an Optease IVC filter. The formation of blood clots in a vein (known as “venous thromboembolism”) is often seen in trauma patients. The researchers reported that despite the use of anticoagulant medication, 13% of the patients developed blood clots (deep vein thrombosis) and IVC thrombosis (clogging of the filter due to blood clots). The authors suggest that the Optease IVC filter, due to its design, may be a “prothrombotic device”, i.e., it may actually promote the formation of blood clots. Removal of the filter was unsuccessful in 13 patients. The doctors expressed concern over the “persistent complications” related to the use of these devices and stated that their routine use in trauma patients “may not be desirable.”
TrapEase IVC Filter
A Japanese study of Cordis’ permament TrapEase IVC filter found that patients who received this filter were at “extremely high risk of strut fractures” as early as two to three years after placement of the filter.
The PRESERVE IVC Filter Study
Approximately 2,100 subjects are currently being enrolled in a five-year study of IVC filters known as the PRESERVE (Predicting the Safety and Effectiveness of Inferior Vena Cava Filters) study. Filters made by seven different IVC filter manufacturers will be tested and 300 subjects will be enrolled for each filter.
The seven filters to be tested (and their manufacturers) are as follows:
- ALN Vena Cava Filter (ALN Implants Chirurgicaux)
- Option™ Elite Retrievable Vena Cava Filter (Rex Medical)
- VenaTech® LP Vena Cava Filter (B. Braun)
- Cook Günther Tulip Vena Cava Filter (Cook Incorporated)
- DENALI® Vena Cava Filter System (C.R. Bard Peripheral Vascular, Inc.)
- OptEase® Retrievable Vena Cava Filter/ Cordis TrapEase® Vena Cava Filter (Cordis Corporation)
- Crux® Vena Cava Filter System (Volcano Corporation)
The study will investigate the major IVC filter complications that have been associated with these medical devices. These include:
Penetration of filter legs through the inferior vena cava wall resulting in:
- hemorrhage or hematoma
- touching or perforation of other organs
- a decision to remove the filter
- Movement of the filter or its parts to a distant site (e.g., heart, lungs).
- Occlusion (blocking) of the inferior vena cava. This can be caused by the filter capturing blood clots or the tendency of the filter to promote the formation of blood clots.
- Deep vein thrombosis that occurred after the implantation of the filter.
- Other serious adverse events.
The project is being guided by the IVC Filter Study Group Foundation, which is jointly sponsored by the Society for Vascular Surgery (SVS) and the Society of Interventional Radiology (SIR). The filter manufacturers are funding the research and collaborating with New England Research Institutes Inc. (NERI) in carrying out the study.
Taking Legal Action
If you or someone you know has been injured by an IVC filter, or is living under the threat of possible injury, the IVC filter lawsuit team at Wisner Baum would like to hear from you.