Findings from a review of the United States Food and Drug Administration Manufacturer and User Facility Device Experience (MAUDE) database reveal that complications occur with significantly higher frequency when retrievable inferior vena cava filters are placed than permanent filters. The study is in press in the Journal of Vascular and Interventional Radiology (JVIR).
Investigators at the Interventional Radiology section at Northwestern University in Chicago, USA, told delegates at the Society of Interventional Radiology’s 39th Annual Scientific Meeting (22–27 March, San Diego, USA) that they aimed to compare the safety of permanent and retrievable inferior vena cava filters by reviewing the self-reported complications with these devices in the MAUDE database from January 2009 – December 2012.
Jessica Andreoli, radiology resident at Northwestern University, Chicago, USA, explained that she recorded the total number of inferior vena cava filter complications self-reported to the MAUDE database during the study period; she specifically categorised the complications by type and rate for all available devices on the market.
The results of the study showed that there were 1,606 reported adverse events involving 1,057 filters. There were 1,394 (86.8%) adverse events involving retrievable inferior vena cava filters and 212 (13.2%) that involved permanent filters (p<0.0001). The number and percentage of each specific adverse event was higher in retrievable inferior vena cava filters when compared to permanent filters. The prevalence of each specific complication varied widely among brands. The most commonly reported adverse events were: fracture (27.1%) for Bard (C R Bard) devices; inferior vena cava penetration (29.9%) for Celect (Cook); and placement difficulties for Optease (Cordis)(30.8%) and Gunther Tulip (Cook, 45%).
“This study suggests that optional filters are inferior to permanent devices in terms of self-reported, device-associated complications,” Andreoli concluded.
Robert J Lewandowski and Robert K Ryu, also from Northwestern University commented: “Retrievable inferior vena cava filters were developed to protect patients against fatal pulmonary embolism, yet allow for their removal when no longer indicated. The engineering intent of retrievable filters compared to permanent devices was to be less stable and lower profile so they could be easily removed. The advantage inherent in being retrievable has rendered these filters to be more prone to device-related complications like migration, fracture, and perforation. Recognising the growing epidemic of device-related complications, the FDA issued a 2010 “Initial Communication” regarding the risk of adverse events associated with long-term use of retrievable filters.
“Our review of the MAUDE database confirms the differing characteristics of permanent and retrievable inferior vena cava filters. The challenge going forward is to optimise the utilisation of both permanent and retrievable inferior vena cava filters, recognising that there is continued need for both types of devices. Patient care and resource utilisation is optimised when careful prospective decision-making is carried out, as well as meticulous follow-up after filter placement. Further, safe and effective use of ancillary techniques to remove retrievable devices is advocated.”
Michael Lee, consultant interventional radiologist and professor of Radiology, Beaumont Hospital Radiology Department, Dublin, commented: “Andreoli et al present reported inferior vena cava filter complication rates from the MAUDE database and show a higher reported complication rate for retrievable filters when compared with permanent filters. In total, there were 1,606 reported complications between 2009 and 2012 with 212 complications reported for permanent filters and 1394 reported for retrievable filters. However, we do not know how many permanent and retrievable filters were placed during this time period. Over the last 10 years, many more retrievable filters are placed compared to permanent filters. Therefore, the overall complication rate for retrievable filters placed is unknown in this study. The CIRSE Retrievable IVC filter registry reported on 628 retrievable filters placed at CIRSE 2013. There were two major complications (<1%) and 14 minor complications (2%).
“In addition, the significance of the complications reported to the MAUDE database are unknown. For instance, we do know that inferior vena cava penetration (214 events reported for retrievable filters) is usually asymptomatic. It is unclear what the significance of placement issues (reported at 219 events) means. Were these failed placements (unlikely) or technical difficulties related to unfamiliarity with the kit or inexperience on the part of the operator? We also do not know whether these filters were placed by interventional radiologists or other specialties. Similarly, inferior vena cava thrombus is always going to be reported more frequently with retrievable filters than with permanent because thrombus is going to be imaged at retrieval. Many of these are dealt with at the time of retrieval without the need for prolonged hospitalisation. The most significant events reported of filter fracture, migration and limb embolization were mainly associated with one filter type which has since been withdrawn from the market. Filter tilt (194 events), may or may not be significant depending on whether the degree of tilt hinders retrieval or not. Interestingly, the number of reported venous thromboembolism/pulmonary embolism events reported (eight for permanent and 22 for retrievable) are low, indicating that filters are fulfilling their primary function.
“In summary, this is an interesting study which should be interpreted with caution. A list of reported complications without the denominator of the total number of filters placed is only a snapshot. The significance of the events listed is also unknown making it difficult to draw any meaningful conclusions. The study does however, point out the deficiencies associated with some filter designs and the lack of level one evidence associated with inferior vena cava filter use.”
Ryu and Lewandowski responded to Lee’s commentary by saying, “We are grateful for Dr Lee’s erudite and insightful comments. We wholeheartedly agree with him that the total number of inferior vena cava filters placed is unknown, making the context of the abstract difficult to completely understand. However, based on an estimate that 75% of all filters placed are retrievable and that there is a pre-existing “legacy” of permanent filters placed over the past several decades (all of which are currently subject to MAUDE scrutiny), we found that a statistically significant difference in complication rates exist between permanent and retrievable filters. While our conclusion is based on an estimate, it is important to note that this is not a blind estimate but based on an existing market share analysis.
We also agree with Dr Lee that most filter strut perforations seem to be asymptomatic. However, it is unknown what the long term implication, if any, of this finding is.
Other investigators have reported cases of symptomatic strut perforations and other associated complications. Given these reports, and our own anecdotal experience with symptomatic strut perforations, we are concerned that long-term strut perforations may potentially lead to a higher complication rate, but until we understand this phenomenon more fully, we advocate an aggressive approach to filter retrieval.
Finally, other investigators have reported filter tilt as an important cause of filter retrieval failure (22% according to Dr Lee’s own publication, and higher in others). We feel strongly that tilt is a critical finding and have reported it accordingly.”