Venous thromboembolic disease is estimated to occur in as many as 1 or 2 patients per 1000 in the United States, with about 60,000–100,000 deaths annually attributed to deep vein thrombosis (DVT) or pulmonary embolism (PE). In hospitalized patients, pulmonary embolism is the third most common cause of death. Anticoagulation is the cornerstone for the treatment of DVT and PE. Inferior vena cava (IVC) filters are indicated in the uncommon occasion where there is anticoagulation treatment failure or a contraindication to anticoagulation ( Table 37.1 ). The development of vena cava interruption in the 1970s was a critical advance in the treatment of these patients. Since the development of retrievable IVC filters, the use of IVC filters has grown rapidly. Despite their wide use, IVC filters are not without risks and complications.
The US Food and Drug Administration (FDA) developed the MAUDE (Manufacturer and User Facility Device Experience) database to enable a general device reporting system, which includes reporting on IVC filters’ complications. MAUDE has its shortcomings, but it is mandatory for facilities and device manufacturers. The FDA requires manufacturers to have an established medical device reporting (MDR) certified by the FDA. On the other hand, the penalties for providers are weak and poorly enforced. An analysis by Andreoli et al. of the MAUDE database reported that the majority of IVC filter complications were associated with retrievable IVC filters (86.8%) compared with permanent IVC filters (13.2%). In that same report, the authors point out that although all filters are FDA approved they are associated with various complications. The most common of these complications associated with these retrievable IVC filters are placement issues (45.1%), IVC penetration (29.9%), and IVC filter fracture (27.1%) ( Table 37.2 ).
|Bard Retrievable a||Cook Celect||OPTEASE||Gunther Tulip||Option||ALN|
|Fracture||288 (27.1%)||31 (19.7%)||9 (8.4%)||3 (5.9%)||2 (18.2%)||1 (20%)|
|Migration||120 (11.3%)||15 (9.6%)||26 (24.3%)||7 (13.7%)||0 (0%)||1 (20%)|
|Limb embolization||131 (12.3%)||16 (10.2%)||2 (1.9%)||0 (0%)|||0 (0%)||1 (20%)|
|Tilt||165 (15.5%)||19 (12.1%)||6 (5.6%)||3 (5.9%)||1 (9.1%)||0 (0%)|
|IVC penetration||161 (15.1%)||47 (29.9%)||2 (1.9%)||3 (5.9%)||1 (9.1%)||0 (0%)|
|VTE/PE||15 (1.4%)||3 (1.9%)||1 (0.9%)||0 (0%)||1 (18.2%)||1 (20%)|
|IVC thrombus||21 (1.9%)||5 (3.2%)||7 (6.5%)||0 (0%)||0 (0%)||0 (0%)|
|Placement issues||144 (13.5%)||15 (9.6%)||33 (30.8%)||23 (45.1%)||2 (27.3%)||1 (20%)|
|Other||18 (1.7%)||6 (3.8%)||21 (19.6%)||12 (23.5%)||2 (18.2%)||0 (0%)|
This is defined as loss of structural integrity of the filter via break or separation. The incidence of this complication has greatly increased with the newer generations of IVC filters. Since the advent of nitinol to make filters deliverable through smaller delivery systems, the filter may not have been as durable. This especially occurs when subjected to numerous cardiac cycles. Newer generations of Nitinol filters have been developed through more robust metalloids. A review of the MAUDE database supports this in that 95% of all filter fractures reported have occurred in retrievable IVC filters. Of the potentially retrievable IVC filters reported, the highest rate of filter fractures has occurred in the Bard group (namely Recovery, G2, G2X, G2Express, Eclipse, and Meridian IVC filters) (27%).
In August 2010, the FDA published a warning concerning 146 cases of filter migration and 56 filter fractures. These events occurred among a variety of filter designs, including the Bard G2. The FDA communication expressed concern that these mechanical failures may be associated with the long-term placement of retrievable filters. The FDA concluded the communication with a recommendation that
“implanting physicians and clinicians responsible for the ongoing care of patients with retrievable IVC filters consider removing the filter as soon as protection from PE is no longer needed.”
In 2013, Morales et al. published a decision analysis to weigh the risks and benefits of retrievable IVC filter use as a function of the filter’s time in situ. In this study they reviewed the medical literature on patients with IVC filters and a transient risk of PE. They assigned weights reflecting relative severity to each adverse event, then defined risk scores as weight×occurrence rate, and then combined the frequency and severity for each type of adverse event. In this analysis the authors found that the net risk score reached its minimum between day 29 and 54 postimplantation. This is consistent with an increasing net risk associated with continued use of retrievable IVC filters in patients with transient, reversible risk of PE. They concluded that for patients with retrievable IVC filters in whom the transient risk of PE has passed, quantitative decision analysis suggests the benefit/risk profile begins to favor filter removal between 29 and 54 days after implantation. The FDA continues to monitor the safety of these implantable devices. Most recently the FDA sent a warning letter to manufacturers regarding deficiencies in manufacturing quality control.
In their report on long-term complications of IVC filters, Wang et al. looked at IVC filters in place for at least 4 years. They found the rate of fracture was 14%, with perforation rates higher in retrievable filters (70%) compared with permanent filters (15%).
IVC Filter Migration and/or Embolization
IVC filter migration is defined as movement of the filter position from its deployment site by >2 cm in either caudal or cephalad direction. IVC filter embolization refers to the movement of the filter or any of its parts to a distant anatomic location. The presence of a mega cava with IVC diameter over 28 mm is a well-known cause of migration and embolization of IVC filters. The instructions for use (IFU) for each filter specify the maximum diameter of the IVC that is suitable for the filter’s use to reduce the risk of this complication. It is important for clinicians to pay attention to IVC diameter to decrease the risk of embolization or migration of the filters.
The use of Nitinol has allowed the creation of more compact IVC filters deliverable through smaller French delivery systems. There is also reduction in the amount of positive fixation in the design of retrievable filters. These factors allow option of retrieval because they are more easily compressed into a retrieval catheter and removed. An undesirable consequence of this, however, is that these filters have less radial force and less in-growth to the vena cava wall, thereby leading to their tendency to migrate or even embolize to remote locations.
From 2005 to 2010, the FDA received a total of 328 reports regarding device migration, 146 for embolization of broken device parts, and 70 for cases of IVC perforation. Reports to the FDA concerning IVC filter migration using the MAUDE database involve problems with retrievable filters over three times more often than with permanent ones. In comparison with other retrievable filters, migration seems to have been reported more often with the Cordis Optease filter than others ( Table 37.3 ).