Tulip Filter Research Articles

Gunther Tulip Filter Strut Penetration: Benign Long-Term Follow-up

PurposeTo describe the natural history of Gunther Tulip filter (GTF) strut penetration based on the computed tomography (CT)–documented distance penetrated over time and any clinical manifestations. Materials and MethodsThe records of 203 patients (mean age, 59.1 years; 59.4% men) who had had an infrarenal GTF placed for venous thromboembolism (84.2%) with contraindications to anticoagulation (95.1%) and had CT follow-up were reviewed retrospectively for clinical or imaging evidence of complications. Filter strut penetration was measured on axial images from the outer caval wall to the inner edge of the distal end of each strut. Filter strut behavior over time was modeled using a linear mixed model. ResultsThe extent of penetration correlated positively with filter dwell time (P < .001) but plateaued at 3.3 mm at 10-year follow-up. At median 4.7-year follow-up 79.3% of patients had at least 1 strut that was >0.2 mm and 31% had a strut >3 mm from the inferior vena caval wall. The extent of strut penetration was greater at all time points for women (P = .002). Abutment or entry into an adjacent structure was identified in 183 struts of 105 (52.7%) filters; of the 80 filters with CT follow-up, 47% showed progression and 19% regressed. There were no symptoms referable to filter strut penetration. ConclusionsGTF struts often penetrate the inferior vena cava progressively; however, this tends to plateau by 10 years. The limited long-term progression and a very low incidence of symptomatic complications together support a noninterventional approach to the finding of an asymptomatic GTF strut penetration.

Abstract No. 143 Gunther tulip filter strut penetration: benign long-term follow-up

IVC filter strut penetration of the caval wall is often cited as an indication for filter removal (1). Though a common finding on CT images, associated clinical manifestations are reported in < 1% of cases (2–5). Nonetheless, the observation of a conical filter strut that appears to penetrate the caval wall remains a concern long-term because it is common, may be progressive, and there are case reports of serious strut-related symptomatic complications. This study was designed to assess the incidence, magnitude, and natural history of vena cava wall penetration by struts of the Gunther Tulip inferior vena cava filter.

Variability in the perception and application of force used in IVC filter retrievals among interventional radiologists

IntroductionA long dwell time is associated with higher inferior vena cava (IVC) filter retrieval complication rates. Manufacturers advise that “excessive force should not be used” during filter retrieval; however, the term “excessive” is subjective and is likely to lead to variability amongst operators. The aims of this study were to 1) ascertain what interventional radiologists consider to be excessive force during filter retrieval and 2) to understand the variability in interventional radiologists’ perception of force. MethodsThe authors recruited interventional radiologists to perform a benchtop simulated filter retrieval. Participants were invited to pull on a modified force tester attached to a Gunther Tulip filter retrieval set (GTRS). The participants were asked to pull as if they were retrieving an IVC filter and stop when they felt it was clinically unsafe to apply greater force. They were then asked to replicate forces of 10N and 50N, respectively. Each of the three tasks was completed three times. Data were obtained on the clinical experience of the participants with specific questions focusing on their filter retrieval practices. ResultsThe range of maximum forces applied during filter retrieval varied between 0.8 and 79.8N. When asked to replicate 10N and 50N, for attempt-1, the median forces produced were 23.5N and 38.1N, respectively. A trend analysis showed that those who overestimate 10N are more likely to apply a greater overall maximum force (rs = 0.622; P < 0.001). ConclusionThere is wide variation in what interventional radiologists consider to be the maximum safe force to apply during IVC filter retrieval. Implications for practiceManufacturers and operators should consider methods in which only a safe range of forces can be applied during an IVC filter retrieval. Operators may wish to undertake ‘personal’ force calibration as part of training in interventional radiology.

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

PurposeInferior 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 methods252 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. ResultsMean 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. ConclusionLarger 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.

03:45 PM Abstract No. 194 Does lateral tilt during inferior vena cava filter placement result in subsequent need for advanced retrieval technique?

To investigate if lateral tilt during placement of an IVC filter is associated with lateral tilt during retrieval or need for advanced retrieval technique. Retrospective review of Gunther Tulip IVC filters placed and retrieved at our institution between 2015 and 2017 (n = 71) was performed after IRB approval. The angle between the filter and IVC was measured on pre-retrieval venogram (measured lateral tilt). Using the spinous processes of the adjacent vertebrae as an internal reference, calculated filter lateral tilt was then obtained by measuring the angle between the filter and spinous reference line (line connecting adjacent spinous processes) and the angle between IVC and spinous reference line. Intraclass correlation (ICC) analysis was performed using a two-way mixed effects ANOVA model to compare measured and calculated tilt demonstrating a high agreement between calculated and measured tilt angles (absolute ICC: 0.993, P<0.0001). Using this validated spinous process internal reference technique, the filter lateral tilt at time of placement was calculated using pre-placement venogram and intra-procedural post-placement spot radiograph. Filter retrievals were classified as standard (conventional snare) or advanced (technique other than conventional snare). Statistical analysis was performed using Stata for Mac v14.2. Dwell time-adjusted agreement between filter tilt angle at the time of placement and retrieval was fair (ICC coefficient = 0.57). Mean difference between tilt angle at the time of placement and retrieval was 4.4±4.2 degrees. A higher filter tilt angle during retrieval was significantly associated with advanced retrieval technique (P=0.026) while tilt angle during placement was not significantly associated with advanced retrieval technique (P=0.068). While higher lateral tilt of the Gunther Tulip filter measured at the time of retrieval is associated with the need for advanced retrieval technique, lateral tilt at the time of placement does not correlate with the need for advanced retrieval technique. Furthermore, lateral tilt at the time of placement is poorly associated with lateral tilt at the time of retrieval.

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.

Denali, Tulip, and Option Inferior Vena Cava Filter Retrieval: A Single Center Experience.

To compare the technical success of filter retrieval in Denali, Tulip, and Option inferior vena cava filters. A retrospective analysis of Denali, Gunther Tulip, and Option IVC filters was conducted. Retrieval failure rates, fluoroscopy time, sedation time, use of advanced retrieval techniques, and filter-related complications that led to retrieval failure were recorded. There were 107 Denali, 43 Option, and 39 Tulip filters deployed and removed with average dwell times of 93.5, 86.0, and 131days, respectively. Retrieval failure rates were 0.9% for Denali, 11.6% for Option, and 5.1% for Tulip filters (Denali vs. Option p=0.018; Denali vs. Tulip p=0.159; Tulip vs. Option p=0.045). Median fluoroscopy time for filter retrieval was 3.2min for the Denali filter, 6.75min for the Option filter, and 4.95min for the Tulip filter (Denali vs. Option p<0.01; Denali vs. Tulip p<0.01; Tulip vs. Option p=0.67). Advanced retrieval techniques were used in 0.9% of Denali filters, 21.1% in Option filters, and 10.8% in Tulip filters (Denali vs. Option p<0.01; Denali vs. Tulip p<0.01; Tulip vs. Option p<0.01). Filter retrieval failure rates were significantly higher for the Option filter when compared to both the Denali and Tulip filters. Retrieval of the Denali filter required significantly less amount of fluoroscopy time and use of advanced retrieval techniques when compared to both the Option and Tulip filters. The findings of this study indicate easier retrieval of the Denali and Tulip IVC filters when compared to the Option filter.

Mechanisms of Günther Tulip filter tilting during transfemoral placement

The purpose of this study was to characterize the mechanisms of Günther Tulip filter (GTF) tilting during transfemoral placement in an experimental model with further validation in a clinical series. In an experimental study, 120 GTF placements in an inferior vena cava (IVC) model were performed using 6 configurations of pre-deployment filter position. The angle between the pre-deployment filter axis and IVC axis, and the proximity of the constrained filter legs to IVC wall prior to deployment were evaluated. The association of those pre-deployment factors with post-deployment filter tilting was analyzed. The association noted in the experimental study was then evaluated in a retrospective clinical series of 21 patients. In the experimental study, there was a significant association between the pre-deployment angle and post-deployment filter tilting (P<0.0001). With a low pre-deployment angle (≤5°), a significant association was noted between filter tilting and the proximity of the constrained filter legs to the far IVC wall (P=0.001). In a retrospective clinical study, a significant association between the pre-deployment angle and post-deployment filter tilting was also noted with a linear regression model (P=0.026). Significant association of the pre-deployment angle with post-deployment GTF tilting was shown in both the experimental and clinical studies. The experimental study also showed that proximity of filter legs is relevant when pre-deployment angle is small. Addressing these factors may result in a lower incidence of filter tilting.

Abstract No. 563 - IVC filter retrieval: comparing the ease of retrieval of Denali and Tulip filters

Abstract No. 563 - IVC filter retrieval: comparing the ease of retrieval of Denali and Tulip filters

Understanding and improving water sanitation practices to improve health outcomes in Malawi

www.thelancet.com/lancetgh 27 Published Online April 8, 2016 Virginia Tech Carilion School of Medicine, Roanoke, VA, USA (P A Muelenaer MD); Virginia Polytechnic and State University, Blacksburg, VA, USA (K Redican PhD, S W Marmagas MPH); Mzuzu University, Mzuzu, Malawi (R H Holm PhD) Correspondence to: Penelope Muelenaer , 6736 Mallard Lake Drive, Roanoke, VA 24018-6931, USA pamuelenaer@carilionclinic. org Understanding and improving water sanitation practices to improve health outcomes in Malawi Penelope A Muelenaer, Kerry J Redican, Susan W Marmagas, Rochelle H Holm Abstract Background Sustainable Development Goals (SDG) for the universal provision of safe drinking water in the household focus on the need for sustainable, eff ective, and acceptable household water treatment. In this study we aimed to: understand baseline practices and knowledge related to household water supply, safety of drinking water, and hygiene and sanitation; and compare the effi cacy and acceptance of three diff erent point-of-use water treatment interventions.Background Sustainable Development Goals (SDG) for the universal provision of safe drinking water in the household focus on the need for sustainable, eff ective, and acceptable household water treatment. In this study we aimed to: understand baseline practices and knowledge related to household water supply, safety of drinking water, and hygiene and sanitation; and compare the effi cacy and acceptance of three diff erent point-of-use water treatment interventions. Methods We undertook a fi eld study of 30 households in a peri-urban neighbourhood adjacent to the city of Mzuzu, Malawi. We used a random number generator to assign households to one of three water purifi cation interventions: boiling, Waterguard chlorine solution (PSI/Malawi, Blantyre, Malawi) , or Tulip table-top ceramic fi lter. We analysed samples taken from a drinking-water storage container in each household at baseline and 2 weeks after baseline, and recorded total coliform and Escherichia coli count s. Participants completed an initial structured questionnaire about water sources used, sanitation, health, water consumption patterns, and socioeconomic variables in their household. Follow-up questionnaires at 1 week and 2 weeks after the intervention, focused on use and acceptance of the assigned treatment modality. We used WHO health risk standards, and correlated drinking water quality with the questionnaire responses. We used Fisher’s exact test for data analysis. Findings Final data analysis included 28 households: nine from the Tulip fi lter group, 10 from Waterguard chlorination, and nine from the group who boiled water. Two households had incomplete data and were excluded from analysis. Before the intervention, 29 of 30 households were not treating their water. The no-risk WHO standard of 0 CFU/100 mL Escherichia coli was met in eight (89%) samples from households assigned to the Tulip fi lter, four (40%) who used Waterguard , and fi ve (56%) that boiled water. Of the households that boiled water three (30%) met criteria for high, or very high risk. No statistical diff erences were noted between the treatment methods (p=0·081). Ratings of water appearance, smell, and taste were highest in the Tulip fi lter group and lowest in those who boiled water. All households that used the Tulip fi lter intervention expressed satisfaction with the method and wanted to continue to use the fi lter. Interpretation This study provides evidence to inform the development of public health educational programmes that promote household drinking water treatment, improved hygiene and sanitation practices for low-income and middleincome countries working to meet the SDGs. While not statistically signifi cant, there was a trend toward superior performance by the Tulip fi lter in eff ective treatment of household water. Future comparisons of these interventions in a larger study would need to be done to achieve the statistical power to detect a signifi cant diff erence in the three household water treatment methods studied. Funding The Pediatric Medical Device Institute. Copyright © Muelenaer et al. Open Access article distributed under the terms of CC BY. Declaration of interests We declare no competing interests.

Abstract No. 669 - Mechanisms of Günther Tulip filter tilting: an experimental and clinical investigation

PurposeTo characterize mechanisms of Günther Tulip filter (GTF) tilting during transfemoral placement using an experimental model.MaterialsIn an experimental study, 120 GTFs were deployed in an inferior vena cava (IVC) model using 6 configurations of pre-deployment filter position. The angle between the pre-deployment filter axis and IVC axis, and the proximity of the constrained filter legs to the IVC wall prior to deployment were evaluated. The associations between significant pre-deployment factors noted in the experimental study were then evaluated in a retrospective clinical series of 17 patients.ResultsIn the experimental study, there was a significant association between a high pre-deployment angle (>5°) and post-deployment tilting (P < 0.0001). With a low pre-deployment angle (≤ 5°), there was a significant association between the proximity of the constrained pre-deployment filter legs to the far IVC wall and subsequent filter tilting (P = 0.001). In a retrospective clinical study, a significant association between the pre-deployment angle and post-deployment tilting was also noted (P = 0.044), with a trend toward statistical significance using an adjusted linear regression model (P = 0.059).ConclusionsThe pre-deployment angle between filter axis and IVC axis, and the proximity of the constrained filter legs to the IVC wall were associated with GTF tilting in an experimental model. Filter tilt due to proximity of the constrained legs to the IVC wall represents a new factor associated with filter tilting, and a mechanism to explain this is demonstrated. A practical solution is presented to address the identified factors related to filter tilting. PurposeTo characterize mechanisms of Günther Tulip filter (GTF) tilting during transfemoral placement using an experimental model. To characterize mechanisms of Günther Tulip filter (GTF) tilting during transfemoral placement using an experimental model. MaterialsIn an experimental study, 120 GTFs were deployed in an inferior vena cava (IVC) model using 6 configurations of pre-deployment filter position. The angle between the pre-deployment filter axis and IVC axis, and the proximity of the constrained filter legs to the IVC wall prior to deployment were evaluated. The associations between significant pre-deployment factors noted in the experimental study were then evaluated in a retrospective clinical series of 17 patients. In an experimental study, 120 GTFs were deployed in an inferior vena cava (IVC) model using 6 configurations of pre-deployment filter position. The angle between the pre-deployment filter axis and IVC axis, and the proximity of the constrained filter legs to the IVC wall prior to deployment were evaluated. The associations between significant pre-deployment factors noted in the experimental study were then evaluated in a retrospective clinical series of 17 patients. ResultsIn the experimental study, there was a significant association between a high pre-deployment angle (>5°) and post-deployment tilting (P < 0.0001). With a low pre-deployment angle (≤ 5°), there was a significant association between the proximity of the constrained pre-deployment filter legs to the far IVC wall and subsequent filter tilting (P = 0.001). In a retrospective clinical study, a significant association between the pre-deployment angle and post-deployment tilting was also noted (P = 0.044), with a trend toward statistical significance using an adjusted linear regression model (P = 0.059). In the experimental study, there was a significant association between a high pre-deployment angle (>5°) and post-deployment tilting (P < 0.0001). With a low pre-deployment angle (≤ 5°), there was a significant association between the proximity of the constrained pre-deployment filter legs to the far IVC wall and subsequent filter tilting (P = 0.001). In a retrospective clinical study, a significant association between the pre-deployment angle and post-deployment tilting was also noted (P = 0.044), with a trend toward statistical significance using an adjusted linear regression model (P = 0.059). ConclusionsThe pre-deployment angle between filter axis and IVC axis, and the proximity of the constrained filter legs to the IVC wall were associated with GTF tilting in an experimental model. Filter tilt due to proximity of the constrained legs to the IVC wall represents a new factor associated with filter tilting, and a mechanism to explain this is demonstrated. A practical solution is presented to address the identified factors related to filter tilting. The pre-deployment angle between filter axis and IVC axis, and the proximity of the constrained filter legs to the IVC wall were associated with GTF tilting in an experimental model. Filter tilt due to proximity of the constrained legs to the IVC wall represents a new factor associated with filter tilting, and a mechanism to explain this is demonstrated. A practical solution is presented to address the identified factors related to filter tilting.

Efficacy of Retrievable Inferior Vena Cava Filter Placement in the Prevention of Pulmonary Embolism during Catheter-Directed Thrombectomy for Proximal Lower-Extremity Deep Vein Thrombosis

Inferior vena cava (IVC) filter placement is not indicated for thrombolytic interventional treatment for deep vein thrombosis (DVT). We analyzed the efficacy and feasibility of retrievable IVC filter placement for the preventive management of embolic shedding during catheter-directed thrombectomy (CDT) for DVT of lower extremity. Seventy patients (35 males and 35 females) who underwent retrievable IVC filter placement to prevent thrombus dislodgement during CDT in all symptomatic DVT with thrombus age suspected within 4weeks of the lower extremity between March 2008 and January 2014 were included in this study. All patients underwent laboratory blood study, duplex ultrasound and/or computed tomography for diagnosis, treatment, and follow-up in accordance with treatment policy of our Uijeongbu St. Mary's hospital. Two types of retrievable IVC filters (OptEase Filter, Cordis, Roden, The Netherlands; Gunther Tulip Filter, Cook, Bloomington, IN) were usedto prevent thromboembolic events during CDT. After filter placement, subcutaneous low-molecular-weight heparin and overlapped to warfarin or new oral anticoagulant tried to achieve a target international normalized ratio (INR) of 2.0-3.0 in warfarin patients. The thrombus was dislodged through the IVC filter during catheter-directed thrombolytic therapy in 22 patients (31.4%). In 22 cases, the thromboses were trapped by the retrievable IVC filter, and follow-up images showed thrombus capture. Thirty-four patients (48.6%) received percutaneous transluminal angioplasty (PTA). Additional stents were inserted in 23 patients (32.8%). Pulmonary embolism (PE) was not observed in patients implanted with retrievable IVC filters. Our study findings suggest that retrieval IVC filter placement during interventional treatments of DVT of lower extremity such as thrombectomy of vein thrombus with or without stent insertion at compressed deep vein is favorable and effective for protecting against PE or lethal complications. We recommend carefully that before the management of DVT thrombus of lower extremity, retrieval IVC filter placement should be considered for preventing morbidity related with the PE.

Bedside intravascular ultrasound-guided inferior vena cava filter placement in medical-surgical intensive care critically-ill patients

Introduction and objectivePulmonary Embolism (PE) is a potentially life-threatening complication of critical illness. Prophylactic inferior vena cava filter (IVC) placement offers a protection rate of 99% against fatal PE. Transportation of critically ill patients from the intensive care unit to the interventional radiology suit is a potential risk and cumbersome. Bedside IVC filter placement offers protection against fatal PE without added risk of transportation. Transabdominal ultrasound visualization of the IVC can be difficult because of patient body habitus or recent abdominal surgeries. Intravascular Ultrasound (IVUS) is an appealing imaging guidance that does not have this limitation. We are aiming at evaluation the safety and outcome of bedside IVUS-guided Günther Tulip filter placement in the intensive care units patients. ResultsThe single venous access technique via the femoral vein was used. Filter placement was successful in 95% of cases (35/37). In two earlier cases filters misplaced at the right iliocaval confluence were fluoroscopically repositioned in the infrarenal IVC. Neither PE nor PE-related mortality was recorded. Renal impairment was seen in 35% of cases (n=13/37). The body mass index calculation in 27 patients revealed obesity in 67% of the patients. ConclusionsBedside IVUS-guided filter placement in medical-surgical critically ill patient in intensive care unit is a feasible, safe and reliable technique for IVC interruption. IVUS may be the most appropriate tool to guide filter insertion in obese patient.

In vitro comparison of Günther Tulip and Celect filters. Testing filtering efficiency and pressure drop

In this study, the trapping ability of the Günther Tulip and Celect inferior vena cava filters was evaluated. Thrombus capture rates of the filters were tested in vitro in horizontal position with thrombus diameters of 3 and 6mm and tube diameter of 19mm. The filters were tested in centered and tilted positions. Sets of 30 clots were injected into the model and the same process was repeated 20 times for each different condition simulated. Pressure drop experienced along the system was also measured and the percentage of clots captured was recorded. The Günther Tulip filter showed superiority in all cases, trapping almost 100% of 6mm clots both in an eccentric and tilted position and trapping 81.7% of the 3mm clots in a centered position and 69.3% in a maximum tilted position. The efficiency of all filters tested decreased as the size of the embolus decreased and as the filter was tilted. The injection of 6 clots raised the pressure drop to 4.1mmHg, which is a reasonable value that does not cause the obstruction of blood flow through the system.

1:57 PM Abstract No. 178 - Effectiveness and complications of routine and advanced inferior vena cava filter retrieval techniques

1:57 PM Abstract No. 178 - Effectiveness and complications of routine and advanced inferior vena cava filter retrieval techniques

Complications of Celect, Günther Tulip, and Greenfield Inferior Vena Cava Filters on CT Follow-up: A Single-Institution Experience

PurposeTo evaluate and compare the rates of complications on follow-up computed tomography (CT) studies of patients with Celect, Günther Tulip, and Greenfield inferior vena cava (IVC) filters. Materials and MethodsRetrospective review of CT studies obtained 0–1,987 days after infrarenal placement of an IVC filter identified 255 Celect, 160 Tulip, and 50 Greenfield filters. Follow-up CT studies were independently evaluated by two observers for IVC perforation, contact with adjacent organs, and filter fracture. Multivariate analysis was performed to identify factors associated with higher rates of IVC perforation, including age, IVC diameter, sex, and history of malignancy. ResultsIVC perforation was observed in 126 of 255 Celect filters (49%) with a mean follow-up of 277 days, 69 of 160 Tulip filters (43%) with a mean follow-up of 437 days, and one of 50 Greenfield filters (2%) with a mean follow-up of 286 days. A significantly higher IVC perforation rate was observed in women (45.5%) compared with men (30.8%; P = .002) and in patients with a history of malignancy (43.7%) compared with patients with no history of malignancy (29.9%; P < .001). Filter fracture was rare, observed in two of 255 Celect filters (0.8%), one of 160 Tulip filters (0.6%), and none of 50 Greenfield filters. ConclusionsNo significant difference was observed in IVC perforation rate between Celect and Tulip filters. Greenfield filters had a significantly lower rate of IVC perforation than Celect and Tulip filters. Higher IVC perforation rates were observed in women and patients with a history of malignancy.

8:40 AM Abstract No. 180 - Inferior vena caval wall perforation on CT by celect and tulip filters: a single institution experience

<h3>Purpose</h3> Evaluate the perforation rates of Cook Celect and Günther Tulip retrievable IVC filters on follow-up CT studies and compare with the perforation rate of permanent IVC filters. <h3>Materials and Methods</h3> Retrospective review of IVC filters placed at our institution between 1/1/2007 and 10/30/2010. Patients with ≥1 follow-up CT studies performed after infrarenal placement of a Celect or Tulip filter were included. The follow-up CT studies were independently evaluated by two observers for IVC perforation (filter leg extending > 3mm beyond the IVC wall). Any discrepancies were resolved by an experienced Interventional Radiologist. The perforation rates were compared with literature perforation rates for permanent IVC filters (0-41%). <h3>Results</h3> 924 retrievable IVC filters were placed in 465 males (50.3%) and 459 females (49.7%) with average age of 60 years (range 16-105). Interobserver agreement was substantial with a Cohen's kappa=0.61. The perforation rates of Celect and Tulip filters were not significantly different (two proportion Z-test, p > 0.05). The perforation rates for the retrievable filters were comparable to the literature perforation rates of permanent filters at the first follow-up. The Celect and combined perforation rates were significantly higher than the highest permanent filter perforation rate in the literature (41%) at the last follow-up (one tailed binomial test, p < 0.01). <h3>Conclusion</h3> Our data show two retrievable IVC filters (Celect and Tulip) have similar perforation rates. There is a trend that the retrievable filter perforation rate increases with time from placement, from comparable to the literature perforation rates of permanent filters at the first follow-up (median 32 days) to higher than the literature perforation rate at the last follow-up (median 112 days). <h3>Reference</h3> ACR-SIR practice guideline for the performance of inferior vena cava (IVC) filter placement for the prevention of pulmonary embolism. Revised 2010 (Resolution 46). Table 1

Caval Penetration by Retrievable Inferior Vena Cava Filters: A Retrospective Comparison of Option and Günther Tulip Filters

PurposeTo compare the frequency of vena caval penetration by the struts of the Option and Günther Tulip cone filters on postplacement computed tomography (CT) imaging. Materials and MethodsAll patients who had an Option or Günther Tulip inferior vena cava (IVC) filter placed between January 2010 and May 2012 were identified retrospectively from medical records. Of the 208 IVC filters placed, the positions of 58 devices (21 Option filters, 37 Günther Tulip filters [GTFs]) were documented on follow-up CT examinations obtained for reasons unrelated to filter placement. In cases when multiple CT studies were obtained after placement, each study was reviewed, for a total of 80 examinations. Images were assessed for evidence of caval wall penetration by filter components, noting the number of penetrating struts and any effect on pericaval tissues. ResultsPenetration of at least one strut was observed in 17% of all filters imaged by CT between 1 and 447 days following placement. Although there was no significant difference in the overall prevalence of penetration when comparing the Option filter and GTF (Option, 10%; GTF, 22%), only GTFs showed time-dependent penetration, with penetration becoming more likely after prolonged indwelling times. No patient had damage to pericaval tissues or documented symptoms attributed to penetration. ConclusionsAlthough the Günther Tulip and Option filters exhibit caval penetration at CT imaging, only the GTF exhibits progressive penetration over time.

Safety and Efficacy of the Gunther Tulip Retrievable Vena Cava Filter: Midterm Outcomes

To evaluate of the medium-term integrity, efficacy, and complication rate associated with the Gunther Tulip vena cava filter. A retrospective study was performed of 369 consecutive patients who had infrarenal Gunther Tulip inferior vena cava filters placed over a 5-year period. The mean patient age was 61.8 years, and 59% were men. Venous thromboembolic disease and a contraindication to or complication of anticoagulation were the indications for filter placement in 86% of patients; 14% were placed for prophylaxis in patients with a mean of 2.3 risk factors. Follow-up was obtained by review of medical and radiologic records. Mean clinical follow-up was 780 days. New or recurrent pulmonary embolus occurred in 12 patients (3.3%). New or recurrent deep-vein thrombosis occurred in 53 patients (14.4%). There were no symptomatic fractures, migrations, or caval perforations. Imaging follow-up in 287 patients (77.8%) at a mean of 731 days revealed a single (0.3%) asymptomatic fracture, migration greater than 2 cm in 36 patients (12.5%), and no case of embolization. Of 122 patients with CT scans, asymptomatic perforations were identified in 53 patients (43.4%) at a mean 757 days. The Gunther Tulip filter was safe and effective at 2-year follow-up. Complication rates were similar to those reported for permanent inferior vena cava filters.

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

Severe tilting of Günther Tulip filter (GTF) may be associated with difficulty in retrieval. To determine if an introducer curving technique of GTF can decrease the tilting degree of GTF in a caval model. 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. 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. 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.