Advanced IVC Filter Retrieval Techniques
Options when risks of permanent device implantation outweigh the potential complications of retrieval.
Although surgical caval interruption for prevention of massive pulmonary thromboembolism (PE) had been performed since before the 1950s, the contemporary era of PE prevention was ushered in by the advent of percutaneously implantable inferior vena cava (IVC) filters in the 1990s. Early IVC filters included permanently implantable devices such as the Bird’s Nest (Cook Medical, Bloomington, IN), the Vena Tech (B. Braun Interventional Systems, Inc., Bethlehem, PA), the Simon Nitinol (Bard Peripheral Vascular, Inc., Tempe, AZ), and the Greenfield (Boston Scientific Corporation, Natick, MA) filters.1,2
These devices proved to be effective in preventing fatal or massive PE in patients with deep venous thrombosis who had contraindications to systemic anticoagulation. Over the past decade, the use of percutaneously implantable IVC filters has skyrocketed, due in large part to the development of retrievable filters that can be removed once they are no longer deemed necessary. In 1999, there were approximately 49,000 IVC filters placed in the US, and in 2012, this number is estimated to reach over 250,000.
RATIONALE FOR AN AGGRESSIVE APPROACH TO FILTER RETRIEVAL
Although IVC filters are essential for treating patients with deep venous thrombosis who have contraindications to anticoagulation, they do not come without the risk of complications. IVC filter strut fracture, migration, and embolization have all been reported with indwelling filters.3-5 Additionally, filter thrombosis and loss of caval patency has been a concern since the time of early permanent percutaneously implanted filters, with rates of caval occlusion ranging from 4% to 30% in longitudinal studies. 2,6-8 Finally, recent reports have increasingly documented higher rates of recurrent venous thromboembolism in patients with indwelling IVC filters.9 These issues highlight the importance of removing retrievable filters once the contraindication to anticoagulation has passed and caval interruption is no longer necessary.
IMPEDIMENTS TO RETRIEVAL OF TEMPORARY IVC FILTERS
Despite the obvious benefits of retrievable filters, studies unfortunately suggest that the retrieval rates of temporary or retrievable filters are quite low and seldom exceed 20% in most series.10,11 In only a minority of the patients who fail to have filter retrieval is there a persistent need for caval interruption, and the remainder fail to have filter retrieval for one of several reasons. The most common reason for retained filters is likely a result of patients being lost to follow-up and not offered retrieval. This is especially true in the trauma population—a group that receives a relatively high percentage of filters placed for prophylactic reasons and is known to have low follow-up rates. Strategies to improve retrieval rates in this group include filter removal before hospital discharge and increased use of IVC filter registries to improve follow-up of patients receiving retrievable filters.12,13
Although technical failure during attempted IVC filter retrieval is a less common reason for filter retention, the incidence of this increases with longer dwell times and with specific technical issues encountered in some patients. Attempting retrieval during the manufacturer’s reported safe retrieval window, as well as familiarity with advanced retrieval techniques highlighted in this article, may help reduce the likelihood of undesired filter retention.
STANDARD IVC FILTER RETRIEVAL
The accepted window of retrievability for each filter generally mirrors the protocols in the device’s premarket clinical trials (Table 1). Several filters are recognized as having an open indication for retrieval (G2 Eclipse, Bard Peripheral Vascular, Inc.; ALN Implants Chirurgicaux, Ghisonaccia, France), with no defined limit to the retrievability window. Despite these retrieval window guidelines, most interventionists have found that filters can be safely retrieved outside of these windows, even though the ease with which they can be retrieved seems to diminish with increasing dwell time. At our institution, we attempt retrieval as soon as the contraindication to anticoagulation has passed, generally proceeding during the same hospitalization or within 2 weeks of hospital discharge.
For standard, normal-risk retrievals, the protocol for retrieval follows that which is outlined in the specific device’s instructions for use. Most currently available filters are retrieved via an internal jugular vein approach using retrieval kits designed for the specific filter, although the basic protocol is similar across most filter types. The procedure is performed under conscious sedation and/or local anesthesia, beginning with duplexguided puncture of the right internal jugular vein and introduction of a 5-F sheath. A pigtail catheter is then advanced over a guidewire to the caval confluence, and venography is performed. If the filter is patent and free from significant clot burden (< 25% filled with thrombus), removal is then performed.
To do this, a stiff guidewire is placed to a level below the filter, and this wire is used to introduce the retrieval kit sheath (9 to 11 F) into the infrarenal IVC. Next, an endosnare catheter or retrieval cone is used to grasp the hook or retrieval hub on the top of the filter device. Once engaged, tension is gently applied to the snare as the retrieval sheath is advanced coaxially over the filter in order to collapse the filter struts and disengage them from the caval wall. The filter is then removed, and completion venography is performed through the sheath.
DECISION MAKING AND TECHNIQUES FOR RETRIEVAL OF TILTED AND ADHERENT FILTERS
Reasons for technical failure of filter retrieval tend to fall in one of two categories: (1) inability to grasp the proximal hook/hub of the filter due to filter tilt, or (2) dense adherence of the filter struts to the caval wall. Predicting which filter retrievals will be technically difficult is not always possible, but generally speaking, longer dwell times and a history of caval thrombosis increases the likelihood of encountering such difficulties. Additionally, specific types of retrieval difficulties can be predicted by filter type, as those without centering arms are more prone to filter tilt and associated hook-capturing difficulties, and those with larger amounts of metal opposing the caval wall tend to become more firmly embedded.
Most of the difficulties encountered during filter removal attempts can be overcome with careful planning and the use of certain advanced retrieval techniques. However, it is important to realize that aggressive attempts at filter retrieval may be associated with increased risks of complications, including access site issues secondary to the large sheath size required, intraprocedural caval thrombosis or vasospasm, and the potential for caval injury and hemorrhage. Additionally, these techniques involve maneuvers that are outside the device manufacturer’s instructions for use, and complication rates for these attempts are poorly defined and must be extrapolated from small, single-institution series reporting on these techniques.14-17
These concerns should be carefully weighed against the long-term risks of indwelling filters, including filter fractures and migration, strut erosion into adjacent structures, loss of caval patency, and increased subsequent deep venous thrombosis risk, and a thorough discussion of these concerns should be undertaken with the patient. During these maneuvers, the patient is fully anticoagulated with intravenous heparin to prevent caval thrombosis, and he or she is kept under moderate sedation so the surgical interventionist can monitor for escalating pain or discomfort during retrieval attempts, which may signify impeding caval injury.
Although some of the contemporary filters available in the US and Europe have centering legs that help prevent filter tilt (G2 Eclipse, Bard Peripheral Vascular, Inc.; Celect, Cook Medical), all filters can nonetheless tilt in a manner in which the retrieval hook lies against the caval wall, and this in turn allows for growth of intimal hyperplastic tissue over the hook, thus preventing capture of the hook by standard techniques (Figure 1). Centering maneuvers are among the techniques used for repositioning the hook to the middle of the cava. Figure 2A demonstrates a steerable 0.035- inch guidewire being directed from the internal jugular vein down to the lateral aspect of the filter (toward the embedded hook). This wire can then be brought out through a sheath in the right common femoral vein and, by applying traction to each end of the wire, the wire helps to deflect the filter away from the wall and toward the center of the cava.
If this is unsuccessful, an angioplasty balloon can be inflated between the wall of the cava (Figure 2B) and the filter to disrupt the intimal hyperplasia that has grown over the filter retrieval hook and to center the filter within the cava. Finally, centering of the filter can be attempted by advancing devices up through a femoral access approach in order to engage the underside of the filter and direct it centrally within the vena cava. Devices that have been utilized for this purpose include the 0.035-inch Reuter tipdeflecting wire guide (Cook Medical), rigid bronchoscopy forceps, and endomyocardial biopsy forceps.
Snare-over-guidewire technique. If centering techniques have not allowed for engagement of the retrieval hook, the snare can be brought over the guidewire, which acts as a “rail-wire” to help line up the retrieval hook with the snare (Figure 3).
Snare-over-loop guidewire technique. Additional centering of the filter and retrieval hook can be accomplished by passing a wire between the struts of the filter and then applying tension to the filter with this wire. This is done by upsizing the standard 9- to 11-F retrieval sheath to a 12- or 14-F sheath (50 cm), reforming a 5-F VCF catheter (Cook Medical) between the legs of the filter (Figure 4A) and then passing a 0.035-inch angled Glidewire (Terumo Interventional Systems, Inc., Somerset, NJ) through the VCF catheter. The floppy end of the wire is then grasped with a snare catheter (Figure 4B and C) and brought out through the internal jugular sheath so that both ends are coming out through the sheath.
The VCF catheter can then be removed, and the snare is reloaded on the two ends of this wire to help guide the snare down to the retrieval hook. Tension is applied to the two ends of the looped guidewire while the snare is advanced over the loop until it can engage the retrieval hook (Figure 4D). Once the hook is grasped with the snare, the wire is removed to allow for collapse of the filter, and the sheath is coaxially advanced over the filter to collapse the filter’s struts and release its attachment from the caval wall (Figure 4E).
Coaxial Double-Sheath Dissection
In addition to filter tilt resulting in coverage of the retrieval hook, some patients have densely adherent tissue that anchors the filter struts to the caval wall so securely that the filter will not separate from the caval wall with a standard amount of force. In these cases, alternating “to-and-fro” movements between the two coaxial sheaths with a gentle twisting motion of the inner sheath can allow dissection of the adherent tissue from the legs of the filter. We generally employ the use of a 10-F, 55-cm sheath placed coaxially within a 14-F, 45-cm Performer sheath (Cook Medical). The inner sheath is used primarily to collapse the filter up to the portion of the struts that are heavily embedded, and the outer sheath is used to dissect tissue away from the filter (Figure 5).
Laser-Assisted Double-Sheath Dissection
Recently, several groups have employed the use of pacemaker lead extraction laser sheaths with the CVX-300 excimer XeCl laser system (Spectranetics Corporation, Colorado Springs, CO) as an adjunct to the double-sheath dissection technique.15,16 This technique is performed by passing the 12-F, 50-cm inner laser cannula (from the 14-F SLS II laser sheath lead extraction system [Spectranetics Corporation], calibrated at 60 mJ/mm2) through a 14-F, 45-cm Performer sheath (Figure 6). A 6-F, 23-cm Brite-Tip sheath (Cordis Corporation, Bridgewater, NJ) is inserted into the end of the laser sheath to achieve hemostasis, as there is no hemostatic valve on the laser sheath. Once the retrieval hook of the filter has been snared, the outer sheath is advanced over the filter until resistance is met (either using a snare catheter alone or in conjunction with the snareover- looped-guidewire technique), and the laser sheath is brought just beyond the outer sheath.
The laser sheath is then activated for 2 to 5 seconds at a time as it is gently advanced down the filter. The laser energy can result in effective photoablation of the intimal hyperplastic tissue around the struts, thereby freeing the filter’s attachment to the wall. Evidence of tissue ablation has been demonstrated on pathologic analysis of retrieved filters by Kuo et al following this procedure; results with this technique appear favorable, although the safety profile has not yet been firmly established.16,17 Series reporting the use of this laser lead extraction system with a similar technique in its intended use for removal of embedded pacemaker wires suggest a major vessel perforation rate of < 5%.17,18
Retrievable IVC filters have allowed for temporary caval interruption to prevent pulmonary embolization in patients with contraindications to anticoagulation. Potential long-term complications due to indwelling filters justify an aggressive approach to filter retrieval, both in terms of patient follow-up and application of advanced techniques for filter retrieval. Aggressive maneuvers to remove heavily embedded or adherent filters can generally be performed safely, but the risk of these maneuvers has not been clearly elucidated and must be weighed against the risks of permanent filter implantation.
Brian G. DeRubertis, MD, is with the Division of Vascular Surgery, David Geffen School of Medicine at UCLA in Los Angeles, California. He has disclosed that he has no financial interests related to this article. Dr. DeRubertis may be reached at (310) 825-3684; email@example.com.
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- Zhu X, Tam MD, Bartholomew J, et al. Retrievability and device-related complications of the G2 filter: a retrospective study of 139 filter retrievals. J Vasc Interv Radiol. 2011;22:806-812.
- Arabi M, Willatt JM, Shields JJ, et al. Retrievability of optional inferior vena cava filters with caudal migration and caval penetration: report of three cases. J Vasc Interv Radiol. 2010;21:923-926.
- McCowan TC, Ferris EJ, Carver DK, et al. Complications of the nitinol vena caval filter. J Vasc Interv Radiol. 1992;3:401-408.
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- Mohan CR, Hoballah JJ, Sharp WJ, et al. Comparative efficacy and complications of vena caval filters. J Vasc Surg. 1995;21:235-245; discussion 245-246.
- PREPIC Study Group. Eight-year follow-up of patients with permanent vena cava filters in the prevention of pulmonary embolism: the PREPIC (Prevention du Risque d’Embolie Pulmonaire par Interruption Cave) randomized study. Circulation. 2005;112:416-422.
- Karmy-Jones R, Jurkovich GJ, Velmahos GC, et al. Practice patterns and outcomes of retrievable vena cava filters in trauma patients: an AAST multicenter study. J Trauma. 2007;62:17-24; discussion 24-25.
- Johnson ON 3rd, Gillespie DL, Aidinian G, et al. The use of retrievable inferior vena cava filters in severely injured military trauma patients. J Vasc Surg. 2009;49:410-416; discussion 416.
- Kalina M, Bartley M, Cipolle M, et al. Improved removal rates for retrievable inferior vena cava filters with the use of a filter registry. Am Surg. 2012;78:94-97.
- Lucas DJ, Dunne JR, Rodriguez CJ, et al. Dedicated tracking of patients with retrievable inferior vena cava filters improves retrieval rates. Am Surg. 2012;78:870-874.
- Van Ha TG, Vinokur O, Lorenz J, et al. Techniques used for difficult retrievals of the Günther Tulip inferior vena cava filter: experience in 32 patients. J Vasc Interv Radiol. 2009;20:92-99.
- Kuo WT, Tong RT, Hwang GL, et al. High-risk retrieval of adherent and chronically implanted IVC filters: techniques for removal and management of thrombotic complications. J Vasc Interv Radiol. 2009;20:1548-1556.
- Kuo WT, Cupp JS, Louie JD, et al. Complex retrieval of embedded IVC filters: alternative techniques and histologic tissue analysis. Cardiovasc Intervent Radiol. 2012;35:588-597.
- Kuo WT, Odegaard JI, Louie JD, et al. Photothermal ablation with the excimer laser sheath technique for embedded inferior vena cava filter removal: initial results from a prospective study. J Vasc Interv Radiol. 2011;22:813-823.
- Wilkoff BL, Byrd CL, Love CJ, et al. Pacemaker lead extraction with the laser sheath: results of the pacing lead extraction with the excimer sheath (PLEXES) trial. J Am Coll Cardiol. 1999;33:1671-1676