Günther Tulip Filter Retrievability Multicenter Study Including CT Follow-up: Final Report

The application of inferior vena cava filters in orthopaedics and current research advances

Deep vein thrombosis is a common clinical peripheral vascular disease that occurs frequently in orthopaedic patients and may lead to pulmonary embolism (PE) if the thrombus is dislodged. pulmonary embolism can be prevented by placing an inferior vena cava filter (IVCF) to intercept the dislodged thrombus. Thus, IVCFs play an important role in orthopaedics. However, the occurrence of complications after inferior vena cava filter placement, particularly recurrent thromboembolism, makes it necessary to carefully assess the risk-benefit of filter placement. There is no accepted statement as to whether IVCF should be placed in orthopaedic patients. Based on the problems currently displayed in the use of IVCFs, an ideal IVCF is proposed that does not affect the vessel wall and haemodynamics and intercepts thrombi well. The biodegradable filters that currently exist come close to the description of an ideal filter that can reduce the occurrence of various complications. Currently available biodegradable IVCFs consist of various organic polymeric materials. Biodegradable metals have shown good performance in making biodegradable IVCFs. However, among the available experimental studies on degradable filters, there are no experimental studies on filters made of degradable metals. This article reviews the use of IVCFs in orthopaedics, the current status of filters and the progress of research into biodegradable vena cava filters and suggests possible future developments based on the published literature by an electronic search of PubMed and Medline databases for articles related to IVCFs searchable by October 2022 and a manual search for citations to relevant studies.

Clinical outcomes of retrievable inferior vena cava filters for venous thromboembolic diseases

Aim: To identify literature evidence assessing retrievable inferior vena cava filter (rIVCF) for venous thromboembolic diseases. Methods: A systematic literature search was conducted to identify relevant references from the mainstay English and Chinese bibliographic databases (search period: January 2003 to October 2019). Results: 80 original studies with 11,413 patients were included in this review. The success rates of deploying the six types of rIVCFs ranged from 98.4 to 100.0%. Denali had the highest retrieval success rate (95.4-97.6%). The incidence rates of fracture and perforation associated with retrieving the six rIVCFs were less than 2%. Conclusion: The approved rIVCF had comparable clinical profiles, except that Denali was easier to be retrieved than other rIVCF.

Inferior vena cava filter tilting between placement and retrieval is associated with caval diameter and need for complex retrieval techniques

PURPOSE

Inferior vena cava (IVC) filter tilt may lead to apex embedment and need for advanced retrieval techniques. This study assesses factors associated with filter tilt change over time and need for complex retrieval procedures.

MATERIALS AND METHODS

252 consecutive patients underwent retrievable IVC filter placement and removal at a single academic institution over 58 months. 182 (72.2%) patients met inclusion criteria. IVC filters included 168 (92.3%) Gunther Tulip and 14 (7.7%) Option filters. The primary outcome was medial-to-lateral IVC filter tilt change between placement and retrieval. Secondary outcomes included advanced retrieval technique use and multiple retrieval attempts. Independent variables included demographics, IVC diameter, filter hook position relative to the renal veins, and dwell time. Associations were determined using student's t-tests, ANOVA, and linear and logistic regressions.

RESULTS

Mean IVC diameter at placement was 19.2 ± 3.3 mm. Mean filter tilts at placement and retrieval were 6.1 ± 4.9° and 5.2 ± 5.0°, respectively. Mean tilt change was 5.0 ± 5.0°. Larger IVC diameter was associated with greater filter tilt change (p = 0.0004). While IVC diameter did not independently predict retrieval difficulty, greater tilt change and prolonged dwell time were associated with increased advanced retrieval technique use (p = 0.01 and 0.002, respectively). Results were unchanged in a subgroup analysis of patients treated with Gunther Tulip filters.

CONCLUSION

Larger IVC diameter predicts increased filter tilt change, which in turn is associated with challenging retrievals. Attention to IVC diameter during filter placement may anticipate tilt-related complications.

Excimer Laser Sheath-Assisted Retrieval of "Closed-Cell" Design Inferior Vena Cava Filters

Background Numerous reports have shown that inferior vena cava filters are associated with clinically significant adverse events. Complicating factors, such as caval incorporation, may lead to technical challenges at retrieval. The use of advanced techniques including the laser sheath have increased technical success rates; however, the data are limited on which filter types necessitate and benefit from its use. Methods and Results From October 2011 to September 2019, patients with inferior vena cava filter dwell times >6 months or with prior failed retrievals were considered for laser sheath-assisted retrieval. Standard and nonlaser advanced retrieval techniques were attempted first; if the filter could not be safely or successfully detached from the caval wall using these techniques, the laser sheath was used. Technical success, filter type, necessity for laser sheath application based on "open" versus "closed-cell" filter design, dwell times, and adverse events were evaluated. A total of 441 patients (216 men; mean age, 54 years) were encountered. Mean dwell times for all filters was 56.6 months, 54.4 among closed-cell filters and 58.5 among open-cell filters (P=0.63). Technical success of retrieval was 98%, with the laser sheath required in 143 cases (40%). Successful retrieval of closed-cell filters required laser sheath assistance in 60% of cases as compared with 7% of open-cell filters (odds ratio, 20.1; P<0.01). In closed-cell inferior vena cava filters, dwell time was significantly associated with need for laser, requiring it in 64% of retrievals with dwell times >6 months (P=0.01). One major adverse event occurred among laser sheath retrievals when a patient required a 2-day inpatient admission for a femoral access site hemorrhage. Conclusions Closed-cell filters may necessitate the use of the laser sheath for higher rates of successful and safe retrieval.

Inferior Vena Cava Filter Evaluation and Management for the Diagnostic Radiologist: A Comprehensive Review Including Inferior Vena Cava Filter-Related Complications and PRESERVE Trial Filters

Inferior vena cava filters are commonly encountered devices on diagnostic imaging that were highlighted in a 2010 Food and Drug Administration safety advisory regarding their complications from long-term implantation. The Predicting the Safety and Effectiveness of Inferior Vena Cava Filters (PRESERVE) trial is an ongoing after-market study investigating the safety and utility of commonly utilized filters in practice today. While most of these filters are safe, prompt recognition and management of any filter-associated complication is imperative to prevent or reduce the morbidity and mortality associated with them. This review is aimed at discussing the appropriate utilization and placement of inferior vena cava filters in addition to the recognition of filter-associated complications on cross-sectional imaging. An overview of the PRESRVE trial filters is also provided to understand each filter's propensity for specific complications.

A Modified Loop Snare Technique for Difficult Retrievals of Inferior Vena Cava Filter and Migrated Coil

The aim of this study was to evaluate the safety and efficacy of a modified loop snare technique for retrieval of difficult inferior vena cava (IVC) filters and migrated coils.A retrospective review of Günther Tulip filter retrievals between January 2014 and February 2017 was performed. A total of 316 IVC filter retrievals were attempted. In 25 cases, the standard technique had failed and our modified loop snare technique was subsequently attempted in 21 of these patients.The retrievals were successful in 20 cases (mean dwell time, 42.6 days, range, 14-102 days). The dwell time of the one failure was 46 days. The retrieval rate increased from 92.1% with the standard technique to 98.4% with the combination of the standard and modified loop snare technique. Unsuccessful retrieval was due to migration and endothelialization of the filter. This technique can also be used to remove migrated coils which cannot be captured by standard techniques. There were no complications from the retrievals.Tilt and endothelialization of filters are the main factors resulting in unsuccessful retrievals with the standard technique. In the present study, we describe an alternative technique for difficult IVC filter retrievals, which can also be used to capture migrated coils and occluders in the aorta and heart.

Vena Cava Filters: A Synopsis of Complications and Related Topics

Deep venous thrombosis and pulmonary embolism constitute common preventable causes of morbidity and mortality. The incidence of venous thromboembolism (VTE) continues to increase. Standard anticoagulation therapy may reduce the risk of fatal PE by 75% and that of recurrent VTE by over 90%. For patients who are not candidates for anticoagulation, a vena cava filter (VCF) may be beneficial. Despite a good overall safety record, significant complications related to VCF are occasionally seen. This review discusses both procedural and non-procedural complications associated with VCF placement and use. We will also discuss VCF use in the settings of pregnancy, malignancy, and the clinical need for more than one filter.

Optional Vena Cava Filters: What, Why, and When

Optional vena cava filters can used to provide either short-term or permanent protection from pulmonary embolism. These devices have recently become available for clinical use in the United States. However, there remains a paucity of data about these devices and their outcomes. This article reviews current and future devices, the rationale behind non-permanent caval filtration, and the generally accepted guidelines for their clinical application.

Evidence-Based Evaluation of Inferior Vena Cava Filter Complications Based on Filter Type

Many inferior vena cava (IVC) filter types, along with their specific risks and complications, are not recognized. The purpose of this study was to evaluate the various FDA-approved IVC filter types to determine device-specific risks, as a way to help identify patients who may benefit from ongoing follow-up versus prompt filter retrieval. An evidence-based electronic search (FDA Premarket Notification, MEDLINE, FDA MAUDE) was performed to identify all IVC filter types and device-specific complications from 1980 to 2014. Twenty-three IVC filter types (14 retrievable, 9 permanent) were identified. The devices were categorized as follows: conical (n = 14), conical with umbrella (n = 1), conical with cylindrical element (n = 2), biconical with cylindrical element (n = 2), helical (n = 1), spiral (n = 1), and complex (n = 1). Purely conical filters were associated with the highest reported risks of penetration (90-100%). Filters with cylindrical or umbrella elements were associated with the highest reported risk of IVC thrombosis (30-50%). Conical Bard filters were associated with the highest reported risks of fracture (40%). The various FDA-approved IVC filter types were evaluated for device-specific complications based on best current evidence. This information can be used to guide and optimize clinical management in patients with indwelling IVC filters.

IVC filter retrieval in adolescents: experience in a tertiary pediatric center

BACKGROUND

Inferior vena cava (IVC) filters are commonly implanted with the intent to prevent life-threatening pulmonary embolism in at-risk patients with contraindications to anticoagulation. Various studies have reported increases in the rate of venous thromboembolism within the pediatric population. The utility and safety of IVC filters in children has not yet been fully defined.

OBJECTIVE

To describe the technique and adjunctive maneuvers of IVC filter removal in children, demonstrate its technical success and identify complications.

MATERIALS AND METHODS

A retrospective 10-year review was performed of 20 children (13 male, 7 female), mean age: 15.1 years (range: 12-19 years), who underwent IVC filter retrieval. Eleven of 20 (55%) were placed in our institution. Electronic medical records were reviewed for filter characteristics, retrieval technique, technical success and complications.

RESULTS

The technical success rate was 100%. Placement indications included: deep venous thrombosis with a contraindication to anticoagulation (10/20, 50%), free-floating thrombus (4/20, 20%), post-trauma pulmonary embolism prophylaxis (3/20, 15%) and pre-thrombolysis pulmonary patient (1/20, 5%). The mean implantation period was 63 days (range: 20-270 days). Standard retrieval was performed in 17/20 patients (85%). Adjunctive techniques were performed in 3/20 patients (15%) and included the double-snare technique, balloon assistance and endobronchial forceps retrieval. Median procedure time was 60 min (range: 45-240 min). Pre-retrieval cavogram demonstrated filter tilt in 5/20 patients (25%) with a mean angle of 17° (range: 8-40). Pre-retrieval CT demonstrated strut wall penetration and tip embedment in one patient each. There were two procedure-related complications: IVC mural dissection noted on venography in one patient and snare catheter fracture requiring retrieval in one patient. There were no early or late complications.

CONCLUSION

In children, IVC filter retrieval can be performed safely but may be challenging, especially in cases of filter tilt or embedding. Adjunctive techniques may increase filter retrieval rates.

Günther-Tulip inferior vena cava filter removal 3334 days after placement

The Günther-Tulip inferior vena cava filter (Cook Medical Inc, Bloomington, Ind) was one of the first inferior vena cava (IVC) filters to be approved by the U.S. Food and Drug Administration for retrieval. Clinical experience has documented that these IVC filters may be safely removed after 12 weeks of implantation. Recent reports have shown that the longer the indwelling time, the higher the retrieval failure rate. We present a case of a successful retrieval of a Günther-Tulip IVC filter 3334 days after implantation. Removal of the Günther-Tulip IVC filter is technically feasible, even after a prolonged indwelling time.

Decision analysis of retrievable inferior vena cava filters in patients without pulmonary embolism

BACKGROUND

Retrievable filters are increasingly implanted for prophylaxis in patients without pulmonary embolism (PE) but who may be at transient risk. These devices are often not removed after the risk of PE has diminished. This study employs decision analysis to weigh the risks and benefits of retrievable filter use as a function of the filter's time in situ.

METHODS

Medical literature on patients with inferior vena cava (IVC) filters and a transient risk of PE were reviewed. Weights reflecting relative severity were assigned to each adverse event. The risk score was defined as weight × occurrence rate and combines the frequency and severity for each type of adverse event. The value function in the decision model combines the following risks: (1) risk in situ; (2) risk of removal, and (3) relative risk without filters. A decreasing net risk score represents a net expected benefit, and an increasing net risk score indicates the expected harm outweighs the expected benefit.

RESULTS

The net risk score reaches 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. The results were insensitive to reasonable variations in the assessed weights and adverse event occurrence rates.

CONCLUSIONS

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.

Introducer curving technique to reduce tilting of transfemoral Gunther Tulip IVC filter: in vitro study

BACKGROUND

Severe tilting of Günther Tulip filter (GTF) may be associated with difficulty in retrieval.

PURPOSE

To determine if an introducer curving technique of GTF can decrease the tilting degree of GTF in a caval model.

MATERIAL AND METHODS

The model was constructed by placing Dacron grafts in bifurcated glass tubes. The study included three groups: Right Straight Group (G(1)), Left Straight Group (G(2)), and Left Curved Group (G(3)). In G(3), a 10-20° angle was curved on the metal introducer before insertion to decrease the angle between inferior vena cava axes and metal introducer (A(CM)). Before GTF was released, the distance between the caval right wall and the apical hook (D(CH1)), and A(CM) were measured. The tilt angle of GTF (A(CF)) was also measured.

RESULTS

In G(1), GTF apex tended to center compared to G(2) (59% vs. 36%, P < 0.01). In G(3), GTF apex tended to center compared to G(2) (71% vs. 36%, P < 0.01). The differences of A(CF) between G(1) and G(2) (2.66 ± 1.80 vs. 4.13 ± 2.07, P < 0.01) and between G(2) and G(3) (4.13 ± 2.07 vs. 2.39 ± 1.79, P < 0.01) were statistically significant. There were significant positive correlations between A(CM) and A(CF), whereas significant negative correlations were detected between D(CH1) and A(CF) in each group.

CONCLUSION

The oblique course of GTF delivery system relative to the axis of the cava causes filter tilt, and thus, curving the introducer prior to its introduction helps to reduce the filter tilt. We recommend a clinical study to determine whether the introducer curving technique improves filter centering and its retrievability.

Introducer curving technique for the prevention of tilting of transfemoral Günther Tulip inferior vena cava filter

Objective

To determine whether the introducer curving technique is useful in decreasing the degree of tilting of transfemoral Tulip filters.

Materials and Methods

The study sample group consisted of 108 patients with deep vein thrombosis who were enrolled and planned to undergo thrombolysis, and who accepted transfemoral Tulip filter insertion procedure. The patients were randomly divided into Group C and Group T. The introducer curving technique was Adopted in Group T. The post-implantation filter tilting angle (ACF) was measured in an anteroposterior projection. The retrieval hook adhering to the vascular wall was measured via tangential cavogram during retrieval.

Results

The overall average ACF was 5.8 ± 4.14 degrees. In Group C, the average ACF was 7.1 ± 4.52 degrees. In Group T, the average ACF was 4.4 ± 3.20 degrees. The groups displayed a statistically significant difference (t = 3.573, p = 0.001) in ACF. Additionally, the difference of ACF between the left and right approaches turned out to be statistically significant (7.1 ± 4.59 vs. 5.1 ± 3.82, t = 2.301, p = 0.023). The proportion of severe tilt (ACF ≥ 10°) in Group T was significantly lower than that in Group C (9.3% vs. 24.1%, χ² = 4.267, p = 0.039). Between the groups, the difference in the rate of the retrieval hook adhering to the vascular wall was also statistically significant (2.9% vs. 24.2%, χ² = 5.030, p = 0.025).

Conclusion

The introducer curving technique appears to minimize the incidence and extent of transfemoral Tulip filter tilting.

Systematic review of the use of retrievable inferior vena cava filters

PURPOSE

To review the available literature on retrievable inferior vena cava (IVC) filters to examine the effectiveness and risks of these devices.

MATERIALS AND METHODS

Investigators searched MEDLINE for clinical trials evaluating retrievable filters and reviewed the complications reported to the Manufacturer and User Facility Device Experience (MAUDE) database of the U.S. Food and Drug Administration (FDA).

RESULTS

Eligibility criteria were met by 37 studies comprising 6,834 patients. All of the trials had limitations, and no studies were randomized. There were 11 prospective clinical trials; the rest were retrospective studies. Despite the limitations of the evidence, the IVC filters seemed to be effective in preventing pulmonary embolism (PE); the rate of PE after IVC placement was 1.7%. The mean retrieval rate was 34%. Most of the filters became permanent devices. Multiple complications associated with the use of IVC filters were described in the reviewed literature or were reported to the MAUDE database; most of these were associated with long-term use (> 30 days). At the present time, the objective comparison data of different filter designs do not support superiority of any particular design.

CONCLUSIONS

In high-risk patients for whom anticoagulation is not feasible, retrievable IVC filters seem to be effective in preventing PE. Long-term complications are a serious concern with the use of these filters. The evidence of the effectiveness and the risks was limited by the small number of prospective studies.

Inferior vena cava filters in children: our experience and suggested guidelines

Although use of inferior vena cava (IVC) filters for prophylaxis against pulmonary embolism (PE) is well reported in adults, long-term studies in children are lacking. We performed retrospective review of imaging and clinical database of IVC filters for the last 12 years. Thirty-five patients (mean age: 15.5 y) underwent filter placement and/or retrieval. Indications for placement were contraindication to anticoagulation with known deep venous thrombosis (DVT) (18) or high risk of venous thromboembolism (5), recurrent DVT despite anticoagulation (1), and prophylaxis before endovascular thrombolysis (8). All filter placements were technically successful without any complications. Filter retrieval was successful in 15 of 19 attempted (79%) at a mean of 42 days. Two complications occurred during retrieval: IVC stenosis successfully treated with angioplasty and contained IVC perforation. Endothelialization of filter prevented retrieval in 4 patients. Mean follow-up was 29.3 months. No patients had IVC thrombosis, breakthrough pulmonary embolism, filter fracture, or embolism. Two patients had recurrent DVT. Our results indicate that IVC filters can be successfully placed and retrieved in children with minimal procedural complications; follow-up demonstrates acceptable complication rate owing to presence of filters. Prophylactic IVC filter placement may be considered before endovascular thrombolysis for lower extremity DVT. Retrievable filters should be used in children for appropriate indications.

Retrievable vena cava filters: a clinical review

Vena cava filters were developed as a method of preventing pulmonary embolism (PE) in patients with venous thromboembolism (VTE) at risk for bleeding from therapeutic anticoagulation. However, the long-term complications of filter placement, such as caval thrombosis, have mitigated some of the benefits, particularly in those patients with only a temporary contraindication to anticoagulation. Retrievable filters were designed to avoid the long-term risks of a permanent filter while still providing short-term protection against PE. As a result, their use has expanded from patients with known thrombosis to those without VTE who are at high risk for developing PE. In this review, we discuss the different types of retrievable filters, indications for their placement, complications that can occur during and after placement, and their use as prophylaxis in surgical patients. Although the use of retrievable filters in patients with known VTE is clear, further studies are needed to establish their prophylactic efficacy in the surgical patient. Until this evidence is available, we recommend that retrievable filters should be used only in patients with acute VTE who are at risk for recurrent thromboembolism and have a transient risk for bleeding.

Optional vena cava filters: indications, management, and results

BACKGROUND

When anticoagulation is contraindicated or ineffective, optional vena cava filters can be used to prevent pulmonary embolism. These devices can be removed within a defined period of time or can remain in the vena cava permanently.

METHODS

The status of optional vena cava filters was studied by a review of the relevant literature found in a selective Medline search from 2000 to 2008, including a Cochrane review and published guidelines.

RESULTS

Optional vena cava filter can be removed up to 20 weeks or even longer after insertion (depending on the filter model) in a small interventional radiological procedure if therapeutic anticoagulation has been achieved or the patient is no longer at risk for venous thromboembolism. Current studies show comparable results for optional filters and permanent filters, but there have not yet been any prospective studies comparing the two filter types.

CONCLUSIONS

Optional vena cava filters are an important addition to the management of venous thromboembolic disease. As only limited data are available to date, the use of optional filters should be considered on an individual case basis.

Optional vena cava filter with disengaging centering struts: retrieval in an animal model

An optional inferior vena cava (IVC) filter prototype was evaluated for safety and long-term retrievability as an initial feasibility study in an animal model. This filter has four centering struts that have the ability to disengage from the filtering cone portion, allowing the legs to slide out of endothelial growth. Retrieval of six filters in three animals was successful up to 27 weeks. There was no substantial filter tilt, migration, or IVC damage. In conclusion, this filter design may help overcome some of the shortcomings in currently approved optional IVC filters, including long-term retrieval difficulties, tilting, or migration.

Intrapartum placement of an inferior vena cava filter for a woman with hereditary antithrombin III deficiency: its role in the prevention of fatal pulmonary embolism

We present a case of a pregnant woman with hereditary antithrombin III deficiency and deep vein thrombosis of the left lower extremity managed by perinatal unfractionated heparin injection with antithrombin III replacement as well as by intrapartum placement of a temporary inferior vena cava filter. A massive thrombus of the right common iliac vein occurred during the intrapartum period despite antithrombin III replacement. An inserted filter could prevent fatal pulmonary embolism in this patient. Hereditary antithrombin III deficiency increases risk of thrombosis during pregnancy. However, discussion on intrapartum management, when anticoagulants are contraindicated due to possible hemorrhage, is minimal. Our experience suggests that thrombosis can occur and develop during the intrapartum period in an antithrombin III deficient woman despite antithrombin III replacement. It may be advisable to manage deliveries with temporary inferior vena cava filters to prevent fatal pulmonary embolism.

Analysis of tilt of the Günther Tulip filter

PURPOSE

To determine the frequency, dimensions, predictors, and sequelae of Günther Tulip filter (GTF) tilt measured at the time of intended retrieval.

MATERIALS AND METHODS

Retrospective review of all medical records and posteroanterior cavograms of 175 patients who underwent both placement and retrieval of the GTF between August 2003 and July 2007 was performed to assess the frequency, dimensions, predictors, and sequelae of tilt.

RESULTS

Tilt occurred at the first retrieval attempt in 159 of the 175 patients (91%). The average degree of tilt was 7.1 degrees (range, 0 degrees-30 degrees), with 87 of the 159 filters with tilt (55%) having a rightward tilt. Compared with the femoral approach, filters placed with a jugular approach demonstrated 4.2 degrees (range of the standard deviation, 3.1 degrees-5.3 degrees) greater tilt at the first retrieval attempt (95% confidence interval=2.6 degrees, 5.7 degrees; P<.001, two-sided Student t test), a greater frequency of tilt of at least 14 degrees (P=.002, two-sided Fisher exact test), and greater rightward tilt predominance (P=.046, one-sided Fisher exact test). Tilt magnitude at the first retrieval attempt correlated positively with the inferior vena cava diameter 40 mm caudal to the renal vein confluence (R=.183, P=.018, Pearson correlation). Within its limitations, this study detected no new cases of pulmonary embolism, caval perforation, or GTF migration. The success rates at the first attempt at retrieval and the cumulative GTF retrieval success rates were 93% (176 of 190 filters) and 97% (181 of 190 filters), respectively. All 29 GTFs with tilt of at least 14 degrees were placed and successfully retrieved by means of a jugular approach with minimal clinical and technical sequelae.

CONCLUSIONS

Frequent GTF tilt detected at the first retrieval attempt can reach at least 14 degrees and is associated with minimal sequelae. Insertion approach and caval diameter are significant factors in GTF tilt.

Form And Function Of Vena Cava Filters: How Do Optional Filters Measure Up?

The function of vena cava filters, preventing pulmonary embolism while maintaining caval patency, is associated with the design. Several characteristics have been reported. This report evaluates retrievable filter designs in comparison with previously marketed designs with respect to efficacy and safety. Three inferior vena cava (IVC) filters (Gunther Tulip, Bard Recovery, and the Cordis OptEase) were compared on the basis of design characteristics associated with function, shape, number of trapping levels, and fixation. Adverse events reported in the literature and to the US Food and Drug Administration Manufacturers and User Facility Device Experience Database (MAUDE) were summarized. The major differences among device types include the fixation, the volume and number of trapping levels, and the amount of metal in the IVC. The MAUDE registry reported adverse events that had been hypothesized from the analysis of in vitro and in vivo testing. The Recovery and OptEase filters had the highest number of clinically important reports. From 12 to 57% were retrieved between 3 days and 11 months. Adaptations made to facilitate retrieval led to unacceptable sequelae. The small number removed, the length of time they are left in place, and the risks associated with retrieval suggest that optional filters may not be equivalent to approved permanent devices.

Use of Rigid Bronchoscopic Forceps in the Difficult Retrieval of the Günther Tulip Inferior Vena Cava Filter

Retrievable inferior vena cava (IVC) filters may, over time, become incorporated into the wall of the IVC, making subsequent removal difficult. The authors present a case in which a Günther Tulip filter was placed prophylactically before gastric bypass surgery. The retrieval hook of the filter became incorporated into the wall of the IVC, preventing the filter from being snared. Eventually, the filter was freed from the wall of the IVC and successfully removed by using rigid bronchoscopy forceps; however, the filter was damaged in the process.

Long-Term Retrievability of IVC Filters: Should We Abandon Permanent Devices?

Thromboembolic disease produces a considerable disease burden, with death from pulmonary embolism in the UK alone estimated at 30,000-40,000 per year. Whilst it is unproven whether filters actually improve longevity, the morbidity and mortality associated with thromboembolic disease in the presence of contraindications to anticoagulation is high. Thus complications associated with filter insertion, and whilst they remain in situ, must be balanced against the alternatives. Permanent filters remain in situ for the remainder of the patient's life and any complications from the filters are of significant concern. Filters that are not permanent are therefore attractive in these circumstances. Retrievable filters, to avoid or decrease long-term filter complications, appear to be a significant advance in the prevention of pulmonary embolism. In this review, we discuss the safety and effectiveness of both permanent and retrievable filters as well as the retrievability of retrievable inferior vena cava (IVC) filters, to explore whether the use of permanent IVC filters can be abandoned in favor of retrievable filters. Currently four types of retrievable filters are available: the Recovery filter (Bard Peripheral Vascular, Tempe, AZ, USA), the Günther Tulip filter (Cook, Bloomington, IN, USA), the OptEase Filter (Cordis, Roden, The Netherlands), and the ALN filter (ALN Implants Chirurgicaux, Ghisonaccia, France). Efficacy and safety data for retrievable filters are as yet based on small series, with a total number of fewer than 1,000 insertions, and follow-up is mostly short term. Current long-term data are poor and insufficient to warrant the long-term implantation of these devices into humans. The case of fractured wire from a Recovery filter that migrated to the heart causing pericardial tamponade requiring open heart surgery is a reminder that any new endovascular device remaining in situ in the long term may produce unexpected problems. We should also bear in mind that the data on permanent filters are much more robust, with reports on over 9,500 cases with follow-up of up to 8 years. The original implantation time of 10-14 days has been extended to more than 100 days as the mean implantation time with some of the filter types. Follow-up (preferably prospective) is necessary for all retrievable filters, whether or not they are retrieved. Until these data become available we should restrict ourselves to the present indications of permanent and retrievable filters. If long-term follow-up data on larger numbers of cases confirm the initial data that retrievable filters are as safe and effective as permanent filters, the use of the retrievable filters is likely to expand.

Clinical Comparison of Two Optional Vena Cava Filters

PURPOSE

To compare the clinical safety and efficiency of two optional inferior vena cava (IVC) filters.

MATERIAL AND METHODS

Ninety-three consecutive Günther Tulip filters (92 patients) were compared with 83 consecutive OptEase filters (80 patients). Filters were placed at the same institution in patients with high-risk multiple trauma or those undergoing neurosurgery with contraindications to primary prophylaxis (70 patients in the Günther Tulip group and 44 in the OptEase group) and in patients with venous thromboembolism and contraindications to anticoagulation (22 patients in the Günther Tulip group and 36 in the OptEase group). The filters were placed in an angiography suite. Catheter vena cavography was performed before filter placement and intended retrieval. Permanent filters were followed-up with duplex ultrasonography and conventional radiography.

RESULTS

All filters were inserted infrarenally without any complications. Fluoroscopy times for placement and retrieval were longer for the Günther Tulip group than the OptEase group. The mean dwelling time was 11 days (range, 3-27 days) for the Günther Tulip filters and 13.8 days (range, 1-34 days) for the OptEase filters. No symptomatic pulmonary emboli (PE) occurred in patients with intended temporary filtration while the devices were in place. Forty-six of the 93 Günther Tulip filters (49%) and 58 of the 83 OptEase filters (70%) were removed. Two Günther Tulip filters could not be retrieved for technical reasons. The mean follow-up for the permanent Günther Tulip (n = 19) and OptEase (n = 8) filters was 41 and 7 months, respectively. One patient from each group had late caval thrombosis. There were no cases of filter migration or disintegration.

CONCLUSION

Both optional IVC filters are safe and seem to prevent symptomatic PE. On the basis of the fluoroscopy times, the OptEase filters appear to be more operator-friendly. Late filter-associated complications are rare with these filter designs.

Angioscopy for experimental evaluation of optional IVC filters

PURPOSE

To demonstrate the feasibility of direct angioscopic visualization of an optional inferior vena cava (IVC) filter in situ and during retrieval.

MATERIALS AND METHODS

Angioscopy was used for direct visualization of optional IVC filters in six sheep. Cavograms were obtained before the filters were retrieved. After successful filter retrieval, segmental IVC perfusion was performed to evaluate filter retrieval-related damage to the IVC wall. Therefore, all branch vessels were ligated before the IVC segment was flushed with normal saline solution until it was fully distended. Then, the inflow was terminated and the IVC segment observed for deflation. Subsequently, the IVC was harvested en bloc, dissected, and inspected macroscopically.

RESULTS

The visibility of IVC filters at angioscopy was excellent. During the retrieval procedure, filter collapse and retraction into the sheath were clearly demonstrated. Angioscopy provided additional information to that obtained with cavography, demonstrating adherent material in three filters. Three filters in place for more than 2 months could not be retrieved because the filter legs were incorporated into the IVC wall. After filter retrieval, there was no perforation at segmental IVC perfusion. At macroscopic inspection of the IVC lumen, a small piece of detached endothelium was found in one animal.

CONCLUSION

Angioscopy enabled the direct evaluation of optional IVC filters in situ and during retrieval. Compared with cavography, angioscopy provided additional information about the filter in situ and the retrieval procedure. Future applications of this technique could include studies of filter migration, compression, and clot-trapping efficacy.