High-risk Retrieval of Adherent and Chronically Implanted IVC Filters: Techniques for Removal and Management of Thrombotic Complications

Inferior Vena Cava Filter Retrieval: Simple to Complex

Retrievable inferior vena cava filters were designed to provide mechanical prophylaxis from pulmonary embolism with the intent for retrieval once no longer indicated, and have been utilized at a high rate since their introduction. Unfortunately, retrieval rates have historically lagged behind, in part due to significant rates of failed standard retrieval techniques for filters with prolonged dwell time. Refinement in advanced retrieval techniques has now allowed (in experienced centers) for safe removal of filters previously considered irretrievable. An individualized approach is necessary for each potential advanced filter retrieval to determine appropriate course of action. This review will emphasize complex filter retrieval techniques amidst a larger discussion of inferior vena cava filters and their management.

Inferior vena cava filter retrievals using advanced techniques: a systematic review

This study aimed to assess the safety of complex inferior vena cava (IVC) filter retrieval techniques through a systematic review of published literature. Using PubMed, a systematic review was conducted in line with the 2020 Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines to identify articles published through April 2020 that reported on complex IVC filter retrieval techniques in >5 patients. Case reports, review papers, and studies that did not report on primary outcomes or variables of interest were excluded. Risk of bias was assessed using a modified Newcastle-Ottawa Quality Assessment scale. Pooled success and complication rates were calculated for the overall number of complex retrieval attempts as well as for each filter type and each complex retrieval method. Sixteen fair-quality and three good-quality studies met the inclusion criteria, with 758 patients (428 female) who had undergone 770 advanced retrieval attempts. The mean age of the patients was 46.5 ± 7.1 years (range: 14.1-90), and the mean dwell time was 602.5 ± 388.6 days (range: 5-7336). Regarding filters, 92.6% (702/758) were retrievable and 7.4% (56/758) were permanent. Indications for complex retrieval included the failure of standard retrieval (89.2%; 676/758) and tilting or embedding in the caval wall (53.8%; 408/758); 92.6% (713/770) of the advanced retrieval attempts were successful. The pooled success rate was 92.0% (602/654) for retrievable filters and 96.4% (53/55) for permanent filters (P = 0.422). Only 2.8% (21/758) of patients experienced major complications, and the major complication rate was not significantly associated with filter type (P = 0.183). Advanced techniques for IVC filter retrieval appear safe for the retrieval of retrievable filters and certain permanent filters, with a low short-term major complication rate. Further studies on complex retrieval techniques used to remove permanent filters should be conducted to clarify their safety with respect to filter type.

Complex Inferior Vena Cava Filter Retrievals: Success Rate and Predictors of Adverse Events at a Large Specialized Referral Center

BACKGROUND. Specialized inferior vena cava (IVC) filter referral centers can achieve improved retrieval outcomes, potentially facilitating complex retrievals after long filter dwell times. OBJECTIVE. The purpose of this study was to determine the success rate of complex IVC filter retrievals at a large specialized IVC filter referral center and to identify predictors of adverse events during complex retrievals. METHODS. This retrospective study included patients who underwent complex IVC filter retrieval from March 2014 to June 2018 at a large regional health system with specialized complex retrieval referral centers and interventional radiologists with expertise in such procedures. Complex retrievals methods included a range of loop snare, coaxial sheath, forceps, and snare techniques. Data were collected from the electronic medical record. The success rate of complex retrieval was determined. Factors associated with adverse events during retrieval procedures were explored. RESULTS. The study included 125 patients (51 women, 74 men; mean age, 60 years). The mean filter dwell time at retrieval was 47.5 months (median, 21.8 months). The complex retrieval success rate was 99.2% on the first attempt and 100.0% overall. A total of 11.2% (14/125) of patients experienced an adverse event during retrieval, including 10.4% (13/125) with minor and 0.8% (1/125) with major events. Prolonged dwell time was the only indication for complex retrieval that was significantly associated with adverse events (adverse event rate, 16.7% for patients with this indication vs 5.1% for patients without this indication; p = .04). In multiple regression analysis, the only significant independent predictor of adverse events was a filter dwell time of 5 years or longer (odds ratio, 6.98 [95% CI, 1.64-29.81]; p = .009). CONCLUSION. In a specialized referral system with expertise in complex retrieval methods, high retrieval success rates can be achieved in patients who have filters with long dwell times. Nonetheless, longer dwell times are associated with adverse events during retrieval procedures. CLINICAL IMPACT. The observations support performing early filter retrieval and referring patients who have filters with prolonged dwell times to specialized centers.

Classification System for Inferior Vena Cava (IVC) Appearance Following Percutaneous IVC Filter Retrieval

OBJECTIVE

There is no classification system for describing inferior vena cava (IVC) injuries. The objective of this study was to develop a standardized grading system for venographic appearance of the IVC following percutaneous IVC filter retrieval.

METHODS

A classification system for the appearance of the IVC on cavograms following percutaneous IVC filter removal was developed consisting of two grading elements; luminal characteristics and extravasation. Luminal narrowing from 0% up to 50% from any cause is grade 1; narrowing between 50 and 99% is grade 2; occlusion is grade 3; and avulsion is grade 4. Absence of extravasation is grade A, contained extravasation is grade B, and free extravasation is grade C. This system was then applied retrospectively to pre- and post-IVC filter retrieval cavograms performed at a single institution from October 2004 through February 2019.

RESULTS

546 retrieval attempts were identified with 509 (93.2%) filters successfully retrieved. 449 cases (88.2%) had both pre-retrieval and post-retrieval imaging appropriate for application of the proposed classification system. Inter-rater reliability was 0.972 for luminal characteristics, 0.967 for extravasation, and 0.969 overall. Consensus grading demonstrated a distribution of 97.3% grade 1, 1.3% grade 2, 1.3% grade 3, and 0.0% grade 4 for post-retrieval luminal characteristics. For extravasation classification, 96.4% of the cases were classified as grade A, 2.7% grade B, and 0.9% grade C.

CONCLUSION

A classification system was developed for describing IVC appearance after IVC filter retrieval, and retrospectively validated using a single center dataset.

Ibero-American Society of Interventionism (SIDI) and the Spanish Society of Vascular and Interventional Radiology (SERVEI) Standard of Practice (SOP) for the Management of Inferior Vena Cava Filters in the Treatment of Acute Venous Thromboembolism

Objectives: to present an interventional radiology standard of practice on the use of inferior vena cava filters (IVCFs) in patients with or at risk to develop venous thromboembolism (VTE) from the Iberoamerican Interventional Society (SIDI) and Spanish Vascular and Interventional Radiology Society (SERVEI). Methods: a group of twenty-two interventional radiologist experts, from the SIDI and SERVEI societies, attended online meetings to develop a current clinical practice guideline on the proper indication for the placement and retrieval of IVCFs. A broad review was undertaken to determine the participation of interventional radiologists in the current guidelines and a consensus on inferior vena cava filters. Twenty-two experts from both societies worked on a common draft and received a questionnaire where they had to assess, for IVCF placement, the absolute, relative, and prophylactic indications. The experts voted on the different indications and reasoned their decision. Results: a total of two-hundred-thirty-three articles were reviewed. Interventional radiologists participated in the development of just two of the eight guidelines. The threshold for inclusion was 100% agreement. Three absolute and four relative indications for the IVCF placement were identified. No indications for the prophylactic filter placement reached the threshold. Conclusion: interventional radiologists are highly involved in the management of IVCFs but have limited participation in the development of multidisciplinary clinical practice guidelines.

Endovascular Rescue of Sheath Perforation During Inferior Vena Cava Filter Retrieval

Introduction

Inferior vena cava (IVC) filter retrieval is generally a straightforward procedure but can be challenging with unique complications. A technique used for endovascular rescue of a patient where sheath perforation by the IVC filter occurred during IVC filter retrieval is described.

Report

A 75 year old man underwent retrieval of an IVC filter that had been in place for 10 months. Using the IVC filter retrieval set from a standard right internal jugular vein approach and the loop-snare technique, the hook and collet were captured, and the filter was collapsed into the retrieval sheath. Approximately halfway through removal of the filter through the sheath, mild resistance was encountered and the tip of the IVC filter was found to have perforated the side of the retrieval sheath. The sheath appeared to have bent slightly in this region, probably weakening the sheath wall and creating angulation, which allowed sheath perforation to occur. From a right common femoral vein approach, an Amplatz wire was used to cannulate the distal end of the perforated sheath. A balloon was then used to pull the perforated sheath with the IVC filter into a larger sheath. After removing the Tuohy-Borst and Luer adapters on the perforated sheath, it was able to be internalised and removed via the femoral vein sheath.

Discussion

The endovascular rescue technique described herein may prove useful to other practitioners encountering similar situations, and the complication shows areas of caution when using the loop-snare retrieval technique.

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.

Procedural complications of inferior vena cava filter retrieval, an illustrated review

Annually, approximately 65,000 inferior vena cava (IVC) filters are placed in the United States (Ahmed et al., J Am Coll Radiol 15:1553-1557, 2018). Approximately 35% of filters are eventually retrieved (Angel et al., J Vasc Interv Radiol 22: 1522-1530 e1523, 2011). Complications during filter retrieval depend heavily on technique and filter position. In this paper, we review risk factors and incidence of complications during IVC filter removal. We also discuss ways these complications could be avoided and the appropriate management if they occur.

A 7-year retrospective review of the technical success of the "low-profile" hangman technique for complicated inferior vena cava (IVC) filter retrievals

PURPOSE

We aimed to assess the safety and effectiveness of a modified low-profile hangman technique.

METHODS

We performed a retrospective review of all filter retrieval procedures performed at a major trauma center, from 2012 to 2019. Records were reviewed for patient demographics, device type, device dwell time, device tilt, embedded hook, success of device retrieval, evidence of caval injury and occurrence of complications.

RESULTS

From 2012 to 2019 there were 473 filter retrieval attempts. An advanced technique was documented in 66 (14%). The low-profile hangman technique alone was documented in 23 procedures (5% of all procedures, 35% of advanced technique procedures). Average screening time was 28 minutes. At the time of retrieval attempt, 9 patients (41%) were anticoagulated. The hangman technique was employed as isolated maneuver in 23 patients and was successful on initial attempt in 22 cases (96%). The average dwell time of filters retrieved by the hangman technique was 228 days (range, 40-903 days; median, 196 days). No procedure-related complications occurred.

CONCLUSION

The retrieval of IVC filters is an important part of offering an IVC filter service. Advanced techniques to retrieve caval filters are multiple, and the risk of complications is increased in these cases. We demonstrate the safety and effectiveness of a new modified and lower-profile hangman technique. This new technique could be performed with only an 11 French venous access sheath using off-the-shelf equipment and it remains a cost-effective approach to complex filter retrieval.

A Single-Institutional Comparative Analysis of Advanced Versus Standard Snare Removal of Inferior Vena Cava Filters

PURPOSE

To investigate differences in procedure time, radiation exposure, and periprocedural complications associated with advanced inferior vena cava (IVC) filter retrieval compared with standard snare retrieval.

MATERIALS AND METHODS

A total of 378 patients underwent standard or advanced IVC filter retrieval over a 5-year period. Technical success, retrieval techniques, fluoroscopy time, radiation dose, and complications were analyzed. All retrieval procedures with techniques other than a "snare-and-sheath" method were categorized as advanced, including failed standard attempts requiring intraprocedural conversion to advanced techniques.

RESULTS

A total of 462 filter retrieval attempts were made in 378 patients (57% female). Success rates for standard and advanced retrieval attempts were 86.8% (317 of 365) and 91.8% (89 of 97), respectively. The rate of periprocedural complications was significantly higher in the advanced retrieval group (P = .006). Complication rates for standard and advanced retrievals were 0.6% (2 of 318; all minor) and 5.2% (5 of 97; 3 minor [3.1%] and 2 major [2.1%]), respectively. The 2 major complications during advanced retrievals included filter fracture and embolization. Average fluoroscopy time for advanced retrievals was significantly higher than for standard retrievals (23.1 min vs 4.3 min; P < .001). Average radiation dose for advanced retrievals was also significantly higher than for standard retrievals (557.2 mGy vs 156.9 mGy; P < .001). Use of general anesthesia was also significantly more common in advanced retrievals compared with standard retrievals (6.2% vs 0.9%; P = .002).

CONCLUSIONS

Advanced filter retrieval results in a similarly high rate of technical success compared with standard snare retrieval but is associated with greater fluoroscopy time, anesthesia requirements, and radiation exposure.

Deep Learning for Automated Classification of Inferior Vena Cava Filter Types on Radiographs

PURPOSE

To demonstrate the feasibility and evaluate the performance of a deep-learning convolutional neural network (CNN) classification model for automated identification of different types of inferior vena cava (IVC) filters on radiographs.

MATERIALS AND METHODS

In total, 1,375 cropped radiographic images of 14 types of IVC filters were collected from patients enrolled in a single-center IVC filter registry, with 139 images withheld as a test set and the remainder used to train and validate the classification model. Image brightness, contrast, intensity, and rotation were varied to augment the training set. A 50-layer ResNet architecture with fixed pre-trained weights was trained using a soft margin loss over 50 epochs. The final model was evaluated on the test set.

RESULTS

The CNN classification model achieved a F1 score of 0.97 (0.92-0.99) for the test set overall and of 1.00 for 10 of 14 individual filter types. Of the 139 test set images, 4 (2.9%) were misidentified, all mistaken for other filter types that appear highly similar. Heat maps elucidated salient features for each filter type that the model used for class prediction.

CONCLUSIONS

A CNN classification model was successfully developed to identify 14 types of IVC filters on radiographs and demonstrated high performance. Further refinement and testing of the model is necessary before potential real-world application.

Arteriovenous Fistula-A Rare Complication of IVC Filter Retrieval

Inferior vena cava (IVC) filters are important devices for patients who are at high risk for developing thrombi and pulmonary embolism but have conditions that preclude the use of pharmacologic anticoagulants. IVC filter retrieval has become an important quality initiative backed by Food and Drug Administration guidelines for prompt removal after the filter is no longer indicated. Filter retrieval is a common procedure that usually has very few complications. However, when the filter is tilted or embedded in the caval wall, advanced techniques of retrieval may be necessary. These techniques have a higher rate of success but also a higher risk of complications such as injury to the IVC. Here, we describe a case of IVC filter retrieval resulting in formation of an arteriovenous fistula between the right renal artery and IVC and subsequent successful repair of this fistula using a vascular plug.

Single-session inferior vena cava filter removal, recanalization, and endovenous reconstruction for chronic iliocaval thrombosis

OBJECTIVE

The objective of this study was to demonstrate the safety and efficacy of treatment of inferior vena cava filter (IVCF)-related chronic iliocaval thrombosis with single-session IVCF retrieval and iliocaval recanalization, thereby optimizing stent deployment and avoiding adverse events (AEs) related to stent placement across an obstructed filter.

METHODS

From January 2015 to April 2018, a cohort of 25 consecutive patients presented for treatment of IVCF-related chronic iliocaval thrombosis with filter retrieval, followed by recanalization with stent placement and adjunctive iliofemoral thrombectomy as needed. Inclusion criteria included computed tomography (CT) imaging and clinical presentations consistent with chronic (>30 days) IVCF-related chronic thrombosis. A retrospective analysis of technical success, clinical success as measured with the Venous Clinical Severity Score, use of advanced filter retrieval techniques, and AEs was performed. Primary patency was evaluated with CT at 1 to 3 months and 1 year. Data analysis was performed using a paired t-test.

RESULTS

There were 25 patients (median age, 58.0 years; standard deviation, 15.6 years) with eight types of IVCF encountered; all were treated in a single session. Technical success was achieved in all patients. Mean improvement in the Venous Clinical Severity Score was 1.4 (95% confidence interval, 1.0-1.7; P < .01) in the venous edema subscore and 0.6 (95% confidence interval, 0.2-1.0; P < .01) in the pain subscore. At 1 to 3 months, iliocaval stent patency was maintained in 96% of patients; unilateral iliac vein stent thrombus was seen in one patient. One-year follow-up was available in eight patients, with CT imaging demonstrating maintained patency. Median filter implantation time was 12.3 months (mean, 41.9 months; range, 0.8-245.1 months; standard deviation, 63.3 months). Advanced IVCF retrieval techniques were required for 17 procedures. One major AE and minor AE occurred; no patients died in the study period.

CONCLUSIONS

Single-session iliocaval recanalization with IVCF retrieval has high rates of technical and clinical success in patients with IVCF-related chronic iliocaval thrombosis.

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

•

Tilt of the IVC filter is the major problem for the filter retrieval rate.

•

External compression on the IVC wall can cause filter tilting.

•

Identifying external compression factors are necessary before insertion of IVC filter.

Objectives

To investigate risk factors for inferior vena cava (IVC) filter abutment, including external compression on the IVC wall, using venous phase computed tomography (CT).

Methods

One-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.

Results

Of 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).

Conclusion

IVC 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.

Success in Optional Vena Cava Filter Retrieval. An Analysis of 246 Patients

OBJECTIVE

This study assessed vena cava filter (VCF) retrieval rates and factors associated with retrieval failure in a single center cohort.

METHODS

We conducted an observational retrospective cohort study. The primary endpoint was the percentage of patients whose VCF was retrieved. We performed logistic regression to identify variables associated with retrieval failure.

RESULTS

During the study period, 246 patients received a VCF and met the eligibility requirements to be included in the study; 151 (61%) patients received a VCF due to contraindication to anticoagulation, 69 (28%) patients had venous thromboembolism (VTE) and a high risk of recurrence, and 26 (11%) patients received a filter due to recurrent VTE while on anticoagulant therapy. Of 236 patients who survived the first month after diagnosis of VTE, VCF was retrieved in 96%. Retrieval rates were significantly lower for patients with recurrent VTE while on anticoagulation, compared with patients with contraindication to anticoagulation or patients with a high risk of recurrence (79% vs. 97% vs. 100%, respectively; P<0.01). Mean time to retrieval attempt was significantly associated with retrieval failure (137.8 ± 65.3 vs. 46.3 ± 123.1 days, P<0.001).

CONCLUSIONS

In this single center study, VCF retrieval success was 96%. A delay in the attempt to retrieve the VCF correlated significantly with retrieval failure.

Endovascular Removal of Inferior Vena Cava Filters with Arterial Penetration

PURPOSE

To evaluate the safety and outcomes of endovascular percutaneous removal of inferior vena cava filters (IVCFs) with elements penetrating an artery.

MATERIALS AND METHODS

From an IVCF retrieval database, computerized tomographic scans of patients who underwent IVCF retrieval from 2011 to 2017 were reviewed for IVCF elements penetrating through the caval wall and into an adjacent arterial wall (AW) or penetrating into an adjacent arterial lumen (AL). Forty-two patients were identified, including 20 with elements penetrating into an AW and 22 with elements penetrating into an AL; 30 of these IVCFs were tip embedded.

RESULTS

All of the filters in both groups were removed. Of the arterial-interacting filters, 9 were removed with the use of standard techniques and 33 with the use of endobronchial forceps. Arterial access was obtained before removal in 3 patients (7%) with post-removal arteriography revealing no abnormalities, such as extravasation, pseudoaneurysm, or new fractured components. There was no significant difference between groups in tip embedding, retrieval technique, or fluoroscopy time.

CONCLUSIONS

Endovascular removal of IVCFs with elements that have penetrated into adjacent arterial walls or lumens can be performed safely in the majority of patients.

Retrievable IVC Filters: Comprehensive Review of Device-related Complications and Advanced Retrieval Techniques

Use of retrievable inferior vena cava filters (RIVCFs) has grown exponentially since their introduction into clinical practice, but many of these devices are not retrieved. Some are not retrieved due to poor clinical follow-up, but other devices remain in situ for extended periods because they present significant technical challenges during retrieval. Because of these and other factors, many of these devices were thus left in place permanently. However, recent data have placed a renewed emphasis on device retrieval due to increased risk of RIVCF-related complications, which are positively correlated with filter dwell time. Development of advanced filter retrieval techniques has had a significant impact on the removal of embedded RIVCFs, permitting retrieval of the majority of devices. The purpose of this article is to present an imaging and data review of the dominant device-related factors that complicate RIVCF retrieval and to describe the relevant advanced retrieval techniques to manage these factors. RIVCF imaging is frequently encountered in daily clinical practice via various imaging modalities. Therefore, diagnostic radiologists can play a vital role in identifying filter-related issues. Familiarity with the context for managing these issues in the interventional suite is essential for improving triage and care of patients with RIVCFs. ^© RSNA, 2017.

Bidirectional Pull-Back Technique for Retrieval of Strut-Embedded Cylinder-Shaped Filters in Inferior Vena Cava

BACKGROUND IVC filters have been widely accepted as an effective method to prevent pulmonary embolism (PE) in patients with deep venous thrombosis (DVT). However, the placement of IVC filters is associated with significant complications and filter retrieval can be challenging when the filter struts are embedded into the caval wall. MATERIAL AND METHODS Over 26 months, we reviewed the safety and efficacy of the bidirectional pull-back technique for removing strut-embedded IVC filters in 15 consecutive patients. Retrieval procedural data such as in-dwell time, retrieval time, and fluoroscopy time were recorded. Clinical outcomes and procedure-related complications were evaluated by venography or enhanced computed tomography. Histologic tissue was analyzed to reveal the pathologic effects of chronic filter implantation. All patients underwent routine clinical follow-up at a mean time of 12 months (range, 8-14 months). RESULTS Technical success of filter retrieval was achieved in 100%, with mean implantation of 46.6 days (range, 27-66 days). Filter types were as follows: OptEase (n=11) and Aegisy (n=4). The mean retrieval time and fluoroscopy time were 21.43±5.42 min and 7.63±2.67 min, respectively. Immediate postprocedure venography showed no procedure-related complications. Thirteen patients discontinued previously prescribed lifelong anticoagulation. There were no long-term complications during follow-up. CONCLUSIONS The bidirectional pull-back technique is safe and efficient for filter retrieval. This complex technique can be particularly useful in selected patients to remove strut-embedded cylindrical-shaped IVC filters previously considered irretrievable.

Can Pre-Retrieval Computed Tomography Predict the Difficult Removal of an Implementing an Inferior Vena Cava Filter?

Purpose:

Implementing an inferior vena cava (IVC) filter is a relatively safe procedure but potential negative long-term effects. The complications for filter retrieval have been noted. We examined filter characteristics on pre-retrieval computed tomography (CT) that were associated with complicated retrieval (CR) of IVC filters.

Materials and Methods:

A retrospective review of IVC filter retrievals between January 2008 and June 2014 was performed to identify patients who had undergone a pre-retrieval CT for IVC filter retrieval. CR was defined as the use of nonstandard techniques, procedural time over 30 min, filter fractures, filter tip incorporation into the IVC wall, and retrieval failure. Pre-retrieval CT images were evaluated for tilt angle in the mediolateral and anteroposterior directions, tip embedding into the IVC wall, degree of filter strut perforation, and distance of the filter tip from the nearest renal vein.

Results:

Of seventy-six patients, twenty-four patients (31.6%) with CRs and 56 patients (73.7%) with non-CR were evaluated for pre-retrieval CT. For IVC filter retrieval with a dwelling time of over 45 days, a tilt of over 15 degrees, the appearance of tip embedding and grade 2 perforation were associated with CR on multivariate analysis. However, for IVC filter retrievals with a dwelling time of less than 45 days, there were no factors associated with CR.

Conclusion:

Pre-retrieval CTs may be more effective for IVC filters with a dwelling time of over 45 days. Therefore, a pre-retrieval CT may be helpful in predicting CR of IVC filters with long dwelling times.

Inferior vena cava filter retrievals, standard and novel techniques

The placement of an inferior vena cava (IVC) filter is a well-established management strategy for patients with venous thromboembolism (VTE) disease in whom anticoagulant therapy is either contraindicated or has failed. IVC filters may also be placed for VTE prophylaxis in certain circumstances. There has been a tremendous growth in placement of retrievable IVC filters in the past decade yet the majority of the devices are not removed. Unretrieved IVC filters have several well-known complications that increase in frequency as the filter dwell time increases. These complications include caval wall penetration, filter fracture or migration, caval thrombosis and an increased risk for lower extremity deep vein thrombosis (DVT). Difficulty is sometimes encountered when attempting to retrieve indwelling filters, mainly because of either abnormal filter positioning or endothelization of filter components that are in contact with the IVC wall, thereby causing the filter to become embedded. The length of time that a filter remains indwelling also impacts the retrieval rate, as increased dwell times are associated with more difficult retrievals. Several techniques for difficult retrievals have been described in the medical literature. These techniques range from modifications of standard retrieval techniques to much more complex interventions. Complications related to complex retrievals are more common than those associated with standard retrieval techniques. The risks of complex filter retrievals should be compared with those of life-long anticoagulation associated with an unretrieved filter, and should be individualized. This article summarizes current techniques for IVC filter retrieval from a clinical point of view, with an emphasis on advanced retrieval techniques.

Complications of inferior vena cava filters

Inferior vena cava (IVC) filter placement is a relatively low risk alternative for prophylaxis against pulmonary embolism in patients with pelvic or lower extremity deep venous thrombosis who are not suitable for anticoagulation. There is an increasing trend in the number of IVC filter implantation procedures performed every year. There are many device types in the market and in the early 2000s, the introduction of retrievable filters brought an additional subset of complications to consider. Modern filter designs have led to decreased morbidity and mortality, however, a thorough understanding of the limitations and complications of IVC filters is necessary to weight the risks and benefits of placing IVC filters. In this review, the complications associated with IVC filters are divided into procedure related, post-procedure, and retrieval complications. Differences amongst the device types and retrievable filters are described, though this is limited by a significant lack of prospective studies. Additionally, the clinical presentation as well as prevention and treatment strategies are outlined with each complication type.

Vena Tech LGM filter retrieval 16 years after implantation: piecemeal removal by intentional mechanical fracture

A 48-year-old man presented with symptomatic inferior vena cava (IVC) occlusion from a chronically thrombosed and embedded Vena Tech LGM filter resulting in exercise intolerance from diminished cardiac preload and postthrombotic syndrome from chronic venous insufficiency. The patient was treated using a new PRIME technique--Piecemeal Removal by Intentional MEchanical fracture--to achieve successful filter retrieval 16 years after implantation. Removal of the obstructing filter permitted endovascular IVC recanalization with restoration of venous outflow and alleviation of venous obstructive symptoms. Cardiac preload was restored, allowing the patient to resume long-distance running, and he successfully completed a half-marathon 3 months after treatment.

Clinical outcomes and causes of death in Japanese patients with long-term inferior vena cava filter implants and deep vein thrombosis

BACKGROUND AND PURPOSE

We assessed the causes of death and efficacy of permanent inferior vena cava (IVC) filters for preventing new pulmonary embolisms (PE) in Japanese deep vein thrombosis (DVT) patients with or without PE.

METHODS AND SUBJECTS

We studied the clinical outcomes during the follow-up period of 1 day to 9 years (median: 18 months; mean: 28 months) in 66 of 72 consecutive patients (44 with acute PE, 27 with intrapelvic DVT, and 1 with floating femoral vein thrombosis). Fifty of 66 patients received anticoagulant therapy after the filter placement.

RESULTS

Five patients died within 1 month (median 9 days) after the filter placement: three from recurrence of PE, one from cancer, and one from sepsis. Two of the three patients with recurrence of PE had preexisting intracardiac thrombi in the right atrium or main pulmonary artery before filter implantation. Ten patients died from the underlying disease (cancer: 7; brain hemorrhage: 1; amyotrophic lateral sclerosis: 1; pneumonia: 1) over 1 month after the filter placement (median follow-up period: 21 months). No new symptomatic PE recurrence was observed over 1 month after the filter placement. The 61 patients with long-term follow-up had no deterioration of DVT, and all the 31 patients who underwent multi-slice computed tomography showed no PE recurrence or filter thrombus occlusion, fracture, or migration.

CONCLUSIONS

Underlying diseases and preexisting intracardiac thrombi may be the determining factors for the prognosis of DVT patients. Permanent IVC filters with anticoagulant therapy may be effective for preventing death from new PE in Japanese DVT patients.

Prevention of pulmonary embolisms associated with vena cava filter implantation

OBJECTIVE

To investigate the prevention of pulmonary embolism (PE) by the implantation of inferior vena cava filters (IVCFs).

METHODS

Data of 1058 patients treated for lower extremity deep vein thrombosis (DVT) between January 2005 and January 2012 were analyzed retrospectively and divided into those with and without PE.

RESULTS

Of the 1058 patients, 34 had PEs (3.2%) and 1024 did not. Multivariable analyses showed that PEs were less likely to occur in patients with IVCFs than in those without IVCFs (odd ratio [OR] =  0.028, P < 0.001), and were more likely to occur in patients with vena cava thrombosis than in those without vena cava thrombosis (OR =  19.094, P < 0.001). Analyses stratified by DVT site showed that vena cava thrombosis was the only risk factor of PE for patients with a left DVT (crude OR =  12.814, P < 0.001), and IVCF implantation was the only protective factor for PE for patients with a right or bilateral DVT (crude OR =  0.028, P =  0.001). IVCF patency rate for follow-up was 98.7% with no filter migration, declination, or failure of expansion.

CONCLUSIONS

IVCFs can reduce the occurrence of PEs in patients with DVTs.

Excimer Laser–Assisted Removal of Embedded Inferior Vena Cava Filters

Background—

Although chronically implanted inferior vena cava filters may result in filter-related morbidity, there is currently no routine option for removing such filters when they become firmly embedded along the vena cava endothelium.

Methods and Results—

During a 3-year period, 100 consecutive patients were prospectively enrolled in a single-center study. There were 42 men and 58 women (mean age, 46 years; limits, 18–76 years). Retrieval indications included filter-related acute inferior vena cava thrombosis, chronic inferior vena cava occlusion, and pain from retroperitoneal or bowel penetration. Filter retrieval was also performed to prevent risks from prolonged implantation and to potentially eliminate the need for lifelong anticoagulation. After standard methods failed, photothermal tissue ablation was attempted with a laser sheath powered by a 308-nm xenon chloride excimer laser. Applied forces were recorded with a digital tension meter before and during laser activation. Laser-assisted retrieval was successful in 98.0% (95% confidence interval [CI], 93.0%–99.8%) with mean implantation of 855 days (limits, 37–6663 days; >18 years). The following filter types were encountered in this study: Günther-Tulip (n=34), Celect (n=12), Option (n=17), Optease (n=20, 1 failure), TrapEase (n=6, 1 failure), Simon-Nitinol (n=1), 12F Stainless Steel Greenfield (n=4), and Titanium Greenfield (n=6). The average force during failed standard retrievals was 7.2 versus 4.6 pounds during laser-assisted retrievals ( P <0.0001). The major complication rate was 3.0% (95% CI, 0.6%–8.5%), the minor complication rate was 7.0% (95% CI, 0.3%–13.9%), and there were 4 adverse events (2 coagulopathic hemorrhages, 1 renal infarction, and 1 cholecystitis; 4.0%; 95% CI, 1.1%–9.9%) at mean follow-up of 500 days (limits, 84–1079 days). Scar tissue ablation was histologically confirmed in 96.0% (95% CI, 89.9%–98.9%). Successful retrieval allowed cessation of anticoagulation in 30 of 30 (100%) patients and alleviated morbidity in 23 of 24 patients (96%).

Conclusions—

Excimer laser–assisted removal is effective in removing embedded inferior vena cava filters refractory to standard retrieval and high force. This method can be safely used to prevent and alleviate filter-related morbidity.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT01158482.

Improving retrieval rates for retrievable inferior vena cava filters

The introduction of retrievable inferior vena cava (IVC) filters was an important step in the evolution of deep vein thrombosis/pulmonary embolism management. Their removability makes them preferred to permanent filters in many cases. IVC filter retrieval often occurs at a suboptimal rate, leading to complications associated with long-term placement. Improving retrievability includes solutions for patients being lost to follow-up, filter malpositioning, need arising for permanent IVC filtration, filtration requiring longer than the filter's window of retrievability, and filter compromise by the presence of a large trapped clot. This review explores these strategies for retrieval in detail in hopes of improving IVC filter retrieval rates.

Retrievable inferior vena cava filters for venous thromboembolism

Inferior vena cava (IVC) filters are used as an alternative to anticoagulants for prevention of fatal pulmonary embolism (PE) in venous thromboembolic disorders. Retrievable IVC filters have become an increasingly attractive option due to the long-term risks of permanent filter placement. These devices are shown to be technically feasible in insertion and retrieval percutaneously while providing protection from PE. Nevertheless, there are complications and failed retrievals with these retrievable filters. The aim of the paper is to review the retrievable filters and their efficacy, safety, and retrievability.

Transcatheter thrombolytic therapy for symptomatic thrombo-occlusion of inferior vena cava filter

Thrombus within an inferior vena cava (IVC) filter reduces filter patency and venous return from the lower extremities, and may progress to complete IVC occlusion. The clinical experiences and outcomes of transcatheter thrombolytic therapy for symptomatic IVC thrombosis following filter implantation have not been widely reported. The aim of the current study was to evaluate the efficiency and safety of trans-catheter thrombolysis for the treatment of symptomatic IVC thrombosis in patients with implanted IVC filters. Transcatheter thrombolysis was used to treat 5 patients with thrombosis of the filter-bearing IVC causing symptoms in 10 limbs from October 2005 to September 2010. The patients were implanted with a second IVC filter through the right internal jugular vein, followed by recanalization of the occluded IVC and intravenous transcatheter thrombolysis. The IVC filters were retrieved through the femoral or right internal jugular vein after the thrombus had dissolved. Technical and clinical outcome, complications and postoperative pulmonary embolism were monitored. A total of 5 filters were implanted and 6 filters were retrieved later. Technically and clinically successful recanalization and thrombolysis were achieved in 5 of 5 patients and 10 of 10 symptomatic limbs. The median thrombolysis period was 13 days (range, 8-14 days). The median dwell time for the filters that were removed was 50.5 days (range, 14-73 days). No major bleeding occurred during the current study. During clinical follow-up, no clinically detectable pulmonary embolism was observed. Endovascular recanalization and transcatheter thrombolysis of IVC thrombosis are efficient, feasible and safe in the presence of an IVC filter.