Filter Tip Research Articles

Successful retrieval of tip-embedded inferior vena cava filter using a modified forceps technique: case report

BackgroundThe retrieval of inferior vena cava (IVC) filter is essential for preventing complications associated with the device. Advanced techniques have been developed to improve the success rate of retrieving tip-embedded filters. The forceps technique is frequently used to address this issue.Case presentationWe present a case study of two patients who underwent a successful tip-embedded IVC filter retrieval using a modified forceps technique, which has not been previously reported. This technique involves using a wire loop under the filter tip and a forceps to grasp the filter shoulder. By pulling the wire loop and pushing the forceps in counterforce, the filter tip is straightened and aligned with the vascular sheath. The vascular sheath can then dissect the filter tip out from the caval wall and get inside the sheath to complete the retrieval.ConclusionsThe modified forceps technique we present here offers a new solution for the complex retrieval of IVC filters.

Inflow and outflow permeability tests in a very soft clay under low stresses

In situ inflow and outflow permeability tests with the BAT probe at Sarapuí II soft clay test site are presented. A description of the BAT permeability test is provided, discussing its advantages and shortcomings, especially in the case of very soft clays under low stresses. Pore pressures were monitored during probe installation and were found to be slightly lower than piezocone u2 pore pressures, consistent with the position of the filter. The role of filter tip saturation was investigated after the usual saturation procedure provided an unsatisfactory pore pressure response during probe installation. Results show that the vacuum saturation procedure provides adequate response during installation and increases the reliability of the coefficient of permeability determination in early measurements. Both inflow and outflow tests yielded similar results, indicating that careful execution of the test can lead to good test repeatability regardless of the loading condition. Various sequences of alternated inflow and outflow tests have yielded similar results, indicating that soil reconsolidation and filter clogging were negligible in the tests performed. Data are presented concerning the relationship between index parameters and the in situ coefficient of permeability for Sarapuí II clay, which plot outside the range of existing databases.

Effectiveness, Retrievability, and Safety of Celect vs. ALN Inferior Vena Cava Filters: A Randomized Prospective Multicenter Controlled Study

The purpose of this study is to compare IVC Celect and ALN filters in regard to their efficacy, retrievability, and one-year follow-up after retrieval. Materials and Methods: This is a prospective randomized study, conducted in three centers between April 2020 and May 2021. A total of 115 participants were randomized, of which 15 participants were excluded for various reasons. Each group of 50 participants was finally assigned a type of filter (Celect n = 50 and ALN = 50). Tilt angles at placement and retrieval, rates of overall filter retrieval, complications, complex retrieval, and clinical follow-up at 12 months were compared. Results: One hundred participants (59 men and 41 women) were included. The mean age was 62.4 ± 13.3, with no significant differences between both groups (p 0.503). The mean of dwelling time was 44.7 ± 93 days. (p 0.520) Filter retrieval was successful in all participants (100%). The main complication in CT prior to removal was tilt >15° (31%) and filter tip embedment (16%). No significant differences were observed in the type of retrieval (standard or complex) between both filters (p 0.24); however, fluoroscopy time was significantly longer in the complex removal of the Celect filter: 29.1 ± 12 min vs. 17.5 ± 10.3 (p 0.005). After one year, no recurrent pulmonary embolism was observed in both types of filters. Conclusions: The ALN filter had a significantly lower rate of tip and filter tip embedding, with no differences in complexity or removal success rate. There were significant differences in the fluoroscopy time consumed for standard and complex retrievals between both filters, with less time for the ALN filter.

Grasp-and-Fold Technique for Complex Inferior Vena Cava Filter Retrieval

This study evaluated the use of the grasp-and-fold technique for complex forceps retrieval of inferior vena cava (IVC) filters. A retrospective study of 14 patients (12 women and 2 men) who had either deeply tip-embedded or severely distorted IVC filters was performed at a single institution over 10 years. In this technique, endobronchial forceps were used to fold the filter in half to remove it through the sheath because the filter tip could not be accessed by dissection. The grasp-and-fold technique successfully removed all 14 filters. One patient had retained filter struts, which were present before the procedure. One mild and 5 moderate adverse events (AEs), including fracture fragment embolization requiring retrieval and self-limited IVC extravasation, occurred. No severe AEs occurred. In this small patient cohort, the grasp-and-fold forceps technique successfully retrieved deeply tip-embedded or distorted IVC filters with inaccessible tips.

1104. Comparison of Antibiotic Sampling Techniques: Predicting Plasma Vancomycin Concentrations Using Volumetric Absorptive Microsampling (VAMS) from Capillary and Venous/Arterial Whole Blood

BackgroundTherapeutic drug monitoring (TDM) is paramount to optimize the safety and efficacy of vancomycin (VAN). In children, TDM is challenged by difficulty in obtaining venous samples, impeding timely sampling. We assessed the ability of volumetric absorptive microsampling (VAMS) as a novel, whole blood sampling technique to predict plasma VAN concentrations in plasma.MethodsWe conducted a prospective pilot study among critically ill children prescribed VAN for clinical care. Coincident with VAN TDM in plasma (P), we collected 20 µL of capillary whole blood (C) and venous/arterial whole blood (V) using VAMS. Paired VAMS-P samples drawn >5 mins apart and VAMS samples with over- or under-loaded filter tip on visual inspection were excluded. Plasma concentrations were measured via chemiluminescent immunoassay in the Chemistry Laboratory. VAMS C and V concentrations were measured using LC/MS in the Bioanalytic Core Laboratory. Plasma concentrations were predicted from whole blood VAMS with Passing-Bablok regression using 3 methods: 1) uncorrected VAMS measures, 2) hematocrit-corrected VAMS, and 3) lab-corrected VAMS (Figure 1). We then assessed bias, imprecision, and accuracy of plasma predictions from VAMS (C and V) as compared to coincident P concentrations for each technique (Figure 1).Figure 1. Methods for relating whole blood vancomycin concentrations collected via VAMS to plasma concentrations and measure to evaluate predictive performance. ResultsPaired samples were collected from 31 enrolled subjects (Figure 2), with a median age of 3.3 years (range 0.1-17.9). Measured P concentrations ranged from 4.6 - 54.9 mg/L. 11 C samples (29%) and 3 V samples (10%) were excluded due to collection issues. Prediction results are shown in Figure 3. The 3 prediction techniques had similar performance characteristics, with each method displaying minimal bias (-0.4-2.0%) and reasonable imprecision (13.7-20.2%). The accuracy of prediction of P concentrations using VAMS was better for V than C samples.Figure 2. Flow diagram from sample collection to evaluation. Abbreviations: C-P, capillary VAMS-plasma; V-P, venous/arterial VAMS-plasma; VAMS, volumetric absorptive microsampling.Figure 3. Performance of 3 techniques to predict plasma vancomycin concentrations using whole blood collected via VAMS. ConclusionOur pilot highlights the challenges of using VAMS for TDM. Sample collection issues were common. When VAMS is used, education on collection techniques is imperative. The predictive performance of VAMS was modest and V sampling had higher accuracy than C, although our sample size was small. Larger studies will be needed to further evaluate the predictive performance of the regression equations derived by our study.Disclosures Kevin J. Downes, MD, Merck, Inc. (Grant/Research Support)

Facile Fabrication of a Functional Filter Tip for Highly Efficient Reduction of Nicotine Content in Mainstream Smoke.

The nicotine addiction problem is of great concern, particularly in adolescents. Notably, nicotine addiction drives humans to continue smoking. Notably, several diseases and disorders are caused by smoking. To date, various adsorbents have been proposed to develop a functionalization filter tip for reducing nicotine content in mainstream smoke. However, the nicotine adsorption efficiencies of most of the reported functionalization filter tips were not satisfactory, and their preparation process was complex and time-consuming. Herein, we demonstrate a highly active and adsorbing filter tip for cigarettes, fabricated by decorating polydopamine (PDA) on the surface of a commercial filter tip in situ. The PDA coating on the filter tip was obtained by the self-polymerization of dopamine (DA) within 16 h, which was quicker and easier than the preparation processes of other reported functionalized filter tips. Significantly, the PDA-decorated filter tip had a nicotine adsorption efficiency as high as ∼95%, which was much higher than most of the commercial filter tips.

A simple electrospinning setup with the Arduino board using cigarette filter tip and liquid glue as the source for fabricating fibres

This article describes a simple setup of electrospinning using widely available resources. The Arduino board, an electronic platform that is commonly accessible was adapted for a controller. Specifically, recycled parts consisting of plastic gears and a lipstick case were incorporated for the construction of a syringe pump. A cheap DC–DC converter was utilized to provide a high voltage supply for stretching of a polymer solution. In order to test the performance of the setup, we obtained the electrospinning fibres with cigarette filter tips dissolved in acetone and liquid glue. The analysis results indicated the average diameter of fibres ∼3.7 ± 0.5 µm and ∼2.8 ± 0.3 µm, respectively. The whole process of controlling can be automatically conducted by a simple application written in DELPHI 7.0 language. It could serve as a form of research project to improve students’ lab experience.

Bottom‐Up Ecofriendly Strategy for Construction of Sustainable Bacterial Cellulose Bioaerogel with Multifunctional Properties

AbstractThe production of sustainable bioaerogel by using renewable biomass via eco‐friendly techniques is a meaningful research topic. This study reports a facile bottom‐up green strategy to construct dimensionally stable bioaerogel derived from bacterial cellulose (BC). Taking advantages of the natural hierarchical and interconnected network structure of BC, the preparation of bioaerogel comprises directional freezing, followed by freeze‐drying approach. Aside from the multifunctional characteristics such as high porosity, low density, and large specific surface area, the resultant BC bioaerogels show superhydrophilic property, excellent water absorption, and swelling characteristics. In addition, the extremely compressed bioaerogel film exhibits flexibility and good mechanical properties. And the BC bioaerogels display a low coefficient of thermal conductivity (25.8 mW m−1 K−1). Moreover, the BC bioaerogels reveal excellent sound absorption at board frequencies from 200 to 6000 Hz with a maximum sound‐absorption coefficient of 0.97. The BC bioaerogel is further used as the green, sustainable, and degradable cigarette filter tip, exhibiting good adsorption effect for the smoke main components. In summary, this study provides a feasible solution to rationally construct lightweight, high porous, heat‐insulating, and highly efficient sound‐adsorption BC bioaerogel, which has potential applications in the future as green advanced functional materials.

Elimination of interfering molybdenum oxyanion with an anion-exchange monolithic spin tip (AXTip) for precise determination of cadmium in human urine by ICP-MS

A simple purification technique using an anion-exchange monolithic spin tip was described for the elimination of molybdenum oxyanion interfering with precise determination of cadmium in human urine samples by ICP-MS. The tip device named “anion-exchange tip-in monolith (AXTip)” was laboratory-prepared within the confines of a commercially available syringe filter tip by a two-step process: (1) in situ copolymerization of glycidyl methacrylate (GMA) and ethylene dimethacrylate (EDMA) and (2) its subsequent modification with trimethylamine (TMA), as a strong anion-exchange functional group, via ring-opening reaction of epoxide. The adsorption capacity of the AXTip was > 3.2 μmol/tip for molybdenum oxyanion. The performance of the AXTip was evaluated through an adsorption/non-adsorption experiment for molybdenum, cadmium and other metal and metalloid species, using a model solution and human urine samples to optimize the sample solution's pH and dilution factor for the AXTip treatment. In the case of urine sample analysis, 8 times dilution and pH adjustment to 4.0 prior to AXTip treatment were found to allow > 98% elimination of interfering molybdenum oxyanions and quantitative recovery (103 ± 7%) of cadmium. At the optimized conditions, the AXTip treatment reduces Mo/Cd ratio from ~400 in human urines to < 10, which is sufficient for conducting ICP-MS measurement of cadmium in no-gas mode (without collision/reaction cell technique). The proposed purification technique was validated through the analysis of an accuracy control material of human urine (Seronorm™ Trace Elements Urine L-1). Good agreement of the observed values with the reference values indicates that the proposed technique is practically applicable.

3:09 PM Abstract No. 283 Denali and Option inferior vena cava filter placement and retrieval: effect of filter type and dwell time on ease of retrieval

To evaluate our experience with placement and retrieval of Argon (Plano, TX) Option Elite and Bard (Tempe, AZ) Denali retrievable inferior vena cava (IVC) filters and compare variables contributing to ease of retrieval. A multicenter retrospective study was performed to review all Option and Denali IVC filters placed and subsequently retrieved over a 60-month period (117 male, median age 48 years, range 18-88). Filters with apex abutting the IVC wall on placement venography were excluded. In total, 191 filters (126 Denali, 65 Option) were successfully deployed and retrieved. Demographics, dwell time, fluoroscopy times, venograms and procedure reports, and complications were recorded. Average dwell times for Option and Denali filters were 110 and 153 days, respectively (P = 0.059). Deployment fluoroscopy times were not different between groups (3.3 vs. 3.5 min, P = 0.51). Retrieval fluoroscopy times were significantly higher for Option filters (11.5 vs. 6.1 min, P = 0.014). Option filters were more likely than Denali to have apex abutment on the caval wall at retrieval (n = 2 vs. 9, P = 0.0012). Use of advanced techniques (beyond a gooseneck snare or retrieval kit alone) were more likely when retrieving the Option (n = 11 vs. 2, P = 0.0002). With regards to filter dwell time, linear regression analysis was performed and Pearson coefficient was calculated, demonstrating an insignificant correlation between filter dwell time and retrieval fluoroscopy time or difference between filter type (Option: r = 0.13, P = 0.30; Denali r = 0.14, P = 0.13). In this patient population, Option filters required increased fluoroscopy time for retrieval and were more likely to demonstrate filter tip abutment against the wall of the IVC at retrieval, with a higher likelihood of requiring advanced retrieval techniques.

Blocking and Filtering Effect of Filter Tips of Natural Fibers against Mainstream Cigarettes Smoke

ABSTRACT Conventional cellulose diacetate filter tips of cigarette (CDFTC) are poor filtration performance of toxic compounds. However, environmentally benign filter tips can be made by replacing cellulose diacetate fibers with various types of natural fibers. In the present work, the blocking and filtering effect of natural fibers such as cotton and wool was examined with regards to the polycyclic aromatic hydrocarbons (PAHs) present cigarette smoke. Using various techniques, including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Fluorescence detection, the blocking and filtering mechanisms were investigated in detail. The results showed that compared with CDFTC, the filter tips made from natural fibers (cotton or wool) were investigated superior at filtering out toxic particles, which is mainly due to the natural twist or crimp along with their longitudinal directions. The efficiency of PHAs removal by the cotton and wool fibers reached 71.0% (with absorption of up to 71.0 µg cig−1) and 60.5% (with absorption of up to 60.5 µg cig−1), respectively. Compared with the Zhongnanhai filter tip used in this study (54.0%), the filtration efficiency of the cotton and wool fibers was increased by 17.0% and 6.5%, respectively.

Over-the-wire deployment techniques of option elite inferior vena cava filter: 3D printing vena cava phantom study

PurposeTo compare filter tilt and filter jumping during Option inferior vena cava (IVC) filter deployment with 3 different wires techniques using a 3-dimensional (3D) printing vena cava phantom. Materials and methodsAn IVC 3D printed vena cava phantom was made from a healthy young male’s computed tomographic data. Option IVC filters were deployed with 3 different wires: i) original push wire, ii) hydrophilic stiff wire, and iii) bent stiff wire. Right internal jugular and right femoral access were used 5 times with each wire. Filter tilt angle, tilt ratio, jumping, and tip abutment to the IVC wall were analyzed. ResultsThe transfemoral approach with original push wire had significantly higher tilt angle than did the transjugular approach (6.1˚ ± 1.9 vs. 3.5˚ ± 1.3, p = 0.04). Mean tilt ratio was significantly lower with the bent wire with transfemoral access (0.49 ± 0.13 vs. 0.78 ± 0.18 [original push-wire] and 0.67 ± 0.08 [stiff wire], p = 0.019). The ratio was lower also with original push wire with transjugular access (0.34 ± 0.19 vs. 0.57 ±0.11 [stiff wire] and 0.58 ±0.17 [bent wire], p = 0.045). Filter jumping occurred more often with the transjugular approach with original push wire than with stiff or bent-wire delivery. Filter tip abutment to the IVC wall occurred only with the transfemoral approach. ConclusionsBent wire with transfemoral access and original push wire with transjugular access had lower filter tilt ratio at Option IVC filter deployment. However, filter jumping was common using the original push wire with transjugular access.

A New Catheter Technique to Correct Severe IVC Filter Tilt during Placement

Abstract Introduction Inferior vena cava (IVC) filter tilt is a common complication that occurs during and after filter placement. Severe tilting leads to reduced filter efficacy, lower retrieval success, and higher complication rates during retrieval. We present a novel catheter technique to correct severely tilted cone-shaped IVC filters without having to retrieve and replace the existing filter. Methods A retrospective review was performed for patients at our institution over three years who had severely tilted filters and underwent correction with the catheter technique. Indications for filter placement were categorized, and patient age, gender, tilt correction outcome, and complication rates were collected and analyzed. After severe tilting was noted on post-IVC filter deployment venogram, a Sos catheter was passed via the same femoral access site used for the filter placement. The catheter tip was reformed inside the cone of the filter and was used to push the filter tip back toward midline. Completion venogram was taken to document the amelioration of the tilt. Results Out of 28 patients who were found to have severely tilted filters on deployment and underwent correction with the catheter technique, 27/28 (96.4%) had successful correction. One (3.6%) had a minor complication where the filter struts became entangled with the catheter tip; however, simple maneuvering of the catheter and use of a stiff wire to straighten the catheter loop freed up the entanglement. No major complications occurred. Conclusion This technique is safe, effective, obviates filter replacement, and can be considered an additional management option for severe IVC filter tilt during placement.

AVN 1. Capturing a Migrating Inferior Vena Cava Filter in a Migratory Patient

Mobile patients present special challenges to their medical teams in solving the care puzzle and formulating an optimal treatment plan. This case of a migratory patient and a migrating filter illustrates the challenges of medical management in these medically complex patients. A 65-year-old patient taking warfarin since 2007 for deep venous thrombosis with an implanted inferior vena cava (IVC) filter since 2008 presented for IVC filter removal because of migration. He has an allergy to contrast material. Surgical history includes the following: IVC filter, Florida, 2008; renal transplantation, Michigan, 2008; bilateral hip replacements, Minnesota, 2015; C4-C7 cervical fusion, Minnesota, 2018; IVC removal, Georgia. His vital signs were normal (weight, 85 kg; height, 188 cm; blood pressure, 127/71 mm Hg). Laboratory values were as follows: hematocrit, 32%; platelet count, 172/mL; international normalized ratio, 2.1; blood urea nitrogen, 38 mg/dL; and creatinine, 1.88 μmol/L. Old outside imaging showed the filter tip near the cavoatrial junction. Under general anesthesia and a sterile preparation, the large patent external jugular vein was accessed. A diagnostic catheter was passed over a 0.035-inch Bentson wire (Cook Medical, Bloomington, Ind) into the iliac vein. A normal finding on carbon dioxide cavography was documented. Unsuccessful recovery with Cook retrieval kit caused the filter hook to straighten and the filter to sit higher in the right atrium. A 0.035-inch wire was passed and a 14F sheath placed in the atrium. An SOS-2 catheter (AngioDynamics, Amsterdam, The Netherlands) was passed over a Bentson wire and retracted to cross between the struts of the filter. The wire tip was ensnared and withdrawn through the sheath to form a completed loop between the legs of the filter. The 14F sheath was advanced over the wire and filter, thus disengaging the legs from the cavoatrial junction. The filter was intact. Completion carbon dioxide venography was unremarkable. This filter was placed more than a decade ago. Imaging from the original insertion was not available. An initial high insertion could not be entirely ruled out. However, the current location abutting the atrium precluded further watchful waiting. Initial filter capture was unremarkable, but straightening of the hook increased the technical difficulty. However, the looped wire technique provided a safe and effective alternative to a technically challenging case.

Multi loop snare technique for difficult inferior vena cava filter retrievals

IntroductionUse of optional vena cava filters has steadily increased. In the majority of cases removal is successful using standard techniques. In cases of tilting and migration of the filter however, more advanced techniques are necessary. The “loop-snare” technique has been described for such cases. Difficulties arise when the loop starts to slip around the legs and arms of the filter.New techniqueWe present an improved loop-snare technique which allows to retrieve IVC filters when the simple loop-snare technique fails. We used additional loops, in one case one additional loop in another case two additional loops around the filter tip which allowed successful retrieval. The additional loops were created with a reversed shaped catheter. All guidewires were then engaged with a snare and pulled into a large sheath. The additional loops stabilize the tip and the filter can be pulled into the sheath.ConclusionThe “multiple-loop-snare” technique is a refinement of the previously described “single loop-snare” technique and can be used when one loop fails.

Femoral versus jugular access for Denali Vena Cava Filter placement: Analysis of fluoroscopic time, filter tilt and retrieval outcomes

PurposeTo analyze relevant metrics involved in Denali Vena Cava Filter placement via different venous access sites. Materials and methodsPatients with Denali filters inserted between March 2017 and February 2018 were retrospectively analyzed. Pre-procedural and pre-retrieval computed tomography (CT) were reviewed. We compared inferior vena cava (IVC) diameter, filter tilt angle, filter tip IVC wall abutment, fluoroscopy time, and retrieval outcomes by venous access site. Filter tip abutment/limb penetration and procedure-related complications were investigated. ResultsSeventy-eight patients had successfully-placed Denali filters. Seventy-one of 78 (91%) patients had both pre-procedural and pre-retrieval CT. The majority (35 [49%]) were placed via the right femoral vein (left femoral vein: 22 [31%]; right internal jugular vein: 14 [20%]). The jugular approach involved a longer fluoroscopy time (mean 117 ± 37 s [s]) than the right and left femoral approaches (mean 64 ± 21 s, mean 67 ± 15 s, respectively [p < 0.05]). Filter tilt and filter tip abutment were not significantly different between the 3 access routes. Filter tip abutment and limb penetration were observed in 8/71 (11%) and 2/71 (3%) patients, respectively. Filter retrieval was attempted in 68 of 78 (87%) cases, and all filters were successfully retrieved. One filter arm fractured during advanced retrieval; no other procedure related complications were recorded. ConclusionsBoth femoral venous approaches can be safely used for placement of the Denali filter. Femoral venous access involved a shorter fluoroscopy time without any differences in filter tilt and filter tip abutment compared to transjugular access.

New method for ultrasound-guided inferior vena cava filter placement

ObjectiveTransabdominal ultrasound (TAUS)-guided inferior vena cava filter (IVCF) placement currently uses an inferior vena cava (IVC) longitudinal plane with cross-section of the right renal artery or the transverse plane of the right renal vein (RRV)-IVC intersection. The goal of this study was to introduce a new method for TAUS-guided IVCF placement. MethodsThe study enrolled patients who were at high risk for or had pulmonary embolism from October 22, 2010, to June 30, 2016. The probe was positioned on the right flank to centralize the RRV-IVC junction during imaging and to permit a straight line through the midpoint of the probe on the surface and a parallel line 1.0 cm below the straight line as a marker. The probe was subsequently placed on the abdominal wall with the upper edge at the marker line to show the long axis of the IVC during the process of filter placement. The upper edge of the probe was considered the filter tip position. ResultsA total of 1029 patients were evaluated, and 98 patients (9.5%) were excluded because of poor IVC visualization (n = 14 [1.4%]), IVC or bilateral iliac vein thrombosis (n = 79 [7.7%]), and unsuitable anatomy (n = 5 [0.5%]). The remaining 931 patients (90.5%) were selected for TAUS-guided IVCF placement, and all filters (100%) were successfully placed. There were no procedure-related complications. Suprarenal IVCF was observed in 4 patients (0.4%) by computed tomography, and the filter tip exceeded the upper edge of L2 in 15 patients (1.6%) by plain film radiography; one of them had two RRVs. Severe filter tilting (20.8 degrees) occurred in one patient. ConclusionsThis new method of TAUS-guided IVCF placement was simple, safe, and effective. It may be widely applied for the bedside placement of vena cava filters.

The recyclability and safety of Celect retrievable vena cava filter

Objective To explore the recyclability and safety of Celect retrievable filter placement in the prevention of pulmonary embolism in patients with deep venous thrombosis (DVT). Methods The data of 120 DVT patients with Celect retrievable filter were collected from the Second Hospital of Shanxi Medical University from August 2015 to March 2017 and analyzed retrospectively. The Celect filter was placed in the inferior vena cava (IVC) at the inferior margin of the renal vein for 1 to 2 cm by puncturing the contralateral femoral vein or right internal jugular vein. The filter retrieve risk was assessed within 8 weeks after being implanted. The filters would be recovered through the right jugular vein when meeting the recovery standard, and the retrieve methods included conventional method, removing the guide wire into a loop trap method and guiding wire into a loop combined with balloon assisted method. The perforation of the vena cava was observed and the tilt angle of the filter was measured. The success rate of Celect filter retrieve was evaluated by the Kaplan-Meier method. Results Celect filters were successfully implanted in 120 patients with DVT. The IVC filters were implanted through femoral vein in 111 patients and 2 cases via right internal jugular vein. No complications, asymptomatic pulmonary embolism and related death was found in all patients. Twenty four patients did not reach the standard of filter retrieve, and were follow-uped. Ninety six cases were treated with Celect retrievable filter, among which, 93 cases were successfully recovered with the filter indwelling time ranging from 7 to 144 days and the median being 50 days. The failure of the filter retrieve occurred in 3 cases because of the serious tilt of the filter or the encapsulation of filter by inferior vena cava thrombus. Perforation of vena cava with no clinical symptoms occurred in 21 cases. Filter tilt was found in 35 cases, among which, 15 cases had inclined angle>15 degrees or the recovery hook closed to the IVC wall. Thirteen cases with filter tip or recovery hook attached to the wall were successfully removed by using the guide wire into a loop or trap guide wire into a loop combined with balloon assisted method instead of routine removal method. The retrieve rate was 100% when the retention time of Celect filter in the body was within 106 days. Conclusion Celect retrievable filter can be implanted in DVT patients with long retrieve time window and high retrieve rate, but the filter inclination rate and vena cava perforation rate are high. Key words: Veinous thrombosis; Pulmonary embolism; Inferior vena cava filter

Filter tilting and retrievability of the Celect and Denali inferior vena cava filters using propensity score-matching analysis

PurposeTo assess the filter tilting and outcomes of the Celect and Denali inferior vena cava (IVC) filters by using a propensity score-matching analysis. Materials and methodsFrom January 2009 to November 2017, 181 Celect and 58 Denali filters were inserted in our institution. To assess filter tilt, filter tip abutment or penetration of the IVC wall, and retrieval outcome, independent variables, including age, sex, IVC long diameter, IVC angulation, and proximity of the filter to renal vein insertion, were entered in the propensity model. Comparative analyses were performed before and after propensity score-matching analysis. ResultsThirty-one patients were enrolled in each group for the final propensity score-matching analysis. The mean filter indwelling time was not significantly different between the groups (26 ± 22 days in Celect and 27 ± 23 days in Denali). After propensity score adjustment, the mean degree of filter tilt was higher in the Celect group (9.5° ± 7.4° vs 5.6° ± 6.7°). Filter tip abutment or penetration of the IVC wall was more common in the Celect group (39% [12/31, abutment: 12, penetration: 0] vs 13% [4/31, abutment: 3, penetration: 1]). The retrieval outcomes were not significantly different before and after propensity score adjustment in both filters. ConclusionThe Denali IVC filter showed less tilt and low rate of filter tip abutment to the IVC wall after propensity score-matching analysis. The retrieval rate was not significantly different in the short-term filter indwelling setting. More large-scale, long-term follow-up studies are needed to verify these results.

Is external compression on the IVC a risk factor for IVC filter abutment? A single center experience of 141 infrarenal celect filter insertions

ObjectivesTo investigate risk factors for inferior vena cava (IVC) filter abutment, including external compression on the IVC wall, using venous phase computed tomography (CT). MethodsOne-hundred-forty-one cases of Celect IVC filter insertion between January 2009 and April 2017 were retrospectively reviewed. On pre-procedural CT, IVC diameter and morphological classifications were measured. Filter tilt angle, IVC angle, vertical position, and filter tip abutment to the IVC wall were analyzed on post-procedural CT. IVC compression was examined by pre- and post-procedural CT analysis. Multiple logistic regression analysis was conducted to find factors related to IVC filter abutment. ResultsOf 141 IVC filter insertion cases, 52 were classified in the filter tip abutment group and 89 in the non-abutting group. IVC tilt angle (11.7 ± 5.5° vs. 6.4 ± 5.4°), presence of external compression (14/52, 27% vs. 9/89, 9%), and IVC morphology were different between the groups (p < 0.05). In multiple logistic regression analysis, filter-tilt angle over 9.25° and external compression on the IVC were found to be independent predictors of filter abutment (odds ratios: 4.56, 10.18, respectively). ConclusionIVC filter tilt, external compression on IVC wall, and IVC morphology were significantly different between the filter tip abutment and non-abutment groups. External compression and filter tilt over 9.25° were risk factors for filter tip abutment in multiple logistic regression analysis. By identifying these factors, we may be able to reduce filter tilting by preventing the filter from being deployed in a dangerous area.