Long-term complications of inferior vena cava filters

Retrieval of a Greenfield Inferior Vena Cava Filter Indwelling for 29 Years

Inferior vena cava (IVC) filters are used to prevent fatal and nonfatal pulmonary embolism in patients who otherwise cannot receive anticoagulation for venous thrombosis. While generally safe and effective, complications can arise, especially after prolonged implantation. Timely retrieval is essential once the indication for insertion has resolved. However, encountering patients with long-standing embedded filters is not uncommon. This case report discusses the successful retrieval of a permanent Greenfield IVC filter after 29 years.

Delayed Arterial Hemorrhage From a Lumbar Artery Following Inferior Vena Cava Filter Placement: A Case Report

Pulmonary embolism (PE) is a feared complication of deep venous thrombosis (DVT) that can lead to respiratory distress and even death. The mainstay of preventing PE is anticoagulation, but other strategies exist. Inferior vena cava (IVC) filters are an alternative strategy for PE prophylaxis in individuals who may have contraindications to receiving anticoagulation. Although the placement of an IVC filter is a minimally invasive and typically uncomplicated procedure, all procedures have their risks. We present a case of a 35-year-old woman who experienced a rare complication of IVC filter placement and suffered a retroperitoneal hemorrhage. The patient underwent placement of an IVC filter for PE prophylaxis before a scheduled sleeve gastrectomy. Hours after placement, she returned with new symptoms and signs of blood loss. She was found to have a retroperitoneal hematoma due to bleeding from a lumbar artery that was penetrated by a strut of the filter. Arterial hemorrhage from a lumbar artery is a rare complication of IVC filter placement, and it can result in poor outcomes for the patient. We aim to increase awareness of this rare but dangerous complication to improve recognition and patient outcomes in cases of delayed arterial hemorrhage following IVC filter placement.

Removing infrarenal inferior vena cava filters (IVCFs) with thrombus under protection of suprarenal IVCFs: A retrospective study in a single-center institution

To determine feasibility of removing inferior vena cava filters (IVCFs) with massive thrombus (>1*1cm) under protection of suprarenal IVCFs, and evaluate the filter thrombus detachment due to removal. The patients who had massive infrarenal IVCFs thrombus and received retrieval under protection of suprarenal IVCFs were retrospectively reviewed from July 2018 to December 2021. Medical data of them including demographics, filter types, dwell time, management, thrombus detachment was collected, and analyzed. There were 33 patients having massive infrarenal IVCFs thrombus and receiving retrieval under protection of suprarenal IVCFs including 23 males and 10 females with a mean age of 55.30 ± 11.97 (range, 30-85 years). All Infrarenal IVCFs were removed successfully and 29 cases (87.88%) were confirmed detachment of thrombus by cavography including 7 small-size thrombus (<1*1cm) and 22 large-size thrombus (>1*1cm). Twenty-two suprarenal IVCFs trapped large-size thrombus were treated with additional anticoagulation and 21 of them had successful retrievals with additional anticoagulation period of 66.18 ± 43.38 days (range, 9-154 days). The large-size IVCFs thrombus may be break off during retrieval, and IVCFs with large-size thrombus could be removed safely with suprarenal IVCFs protection. The thrombus trapped in filters could be reduced with an additional period of anticoagulation.

Inferior Vena Cava Filters and Complications: A Systematic Review

Inferior vena cava (IVC) filters have been used since the 1960s to treat patients with acute risk of pulmonary embolism (PE) to prevent migration of thrombus by trapping it within the filter. Traditional usage has been in patients with contraindication to anticoagulation that carry a significant mortality risk. In this systematic review, we sought to evaluate complications associated with placement of inferior vena cava filters based on published data from the past 20 years. A search was performed on October 6th, 2022, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for systematic reviews, using three databases (ProQuest, PubMed and ScienceDirect) for articles published between the dates of February 1, 2002 and October 1, 2022. Results were filtered to include full-text, clinical studies, and randomized trials written in English pertaining to keywords "IVC filter AND complications", "Inferior Vena Cava Filter AND complications", "IVC filter AND thrombosis" and "Inferior Vena Cava Filter AND thrombosis". Articles identified by the three databases were pooled and further screened for relevance based on inclusion and exclusion criteria. Initial search results yielded 33,265 hits from all three databases combined. Screening criteria were applied, with 7721 results remaining. After further manual screening, including removal of duplicate hits, a total of 117 articles were selected for review. While there are no consensus guidelines for best practice, there is compelling evidence that IVC filters can provide significant protection against PE with minimal complications if the treatment window is appropriate. Increase in the variety of filter models has led to broader availability, but skepticism remains about their efficacy and safety, with ongoing controversy surrounding appropriate indications. Further research is needed to establish clear guidelines on appropriate indications for IVC placement and to determine time course of complications versus benefits for indwelling filters.

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.

Outcome of anticoagulation with rivaroxaban in patients with non-retrieved inferior vena cava filters for the prevention of filter thrombosis: a retrospective cohort study

Background

Non-retrieved inferior vena cava filter (IVCF) is associated with some severe complications, such as filter thrombosis. The aim of this retrospective cohort study was to evaluate the outcome of rivaroxaban for the prevention of filter thrombosis in patients with non-retrieved IVCF.

Methods

The study based on the VTE registry databases was limited to patients with non-retrieved IVCF treated at Nanjing Drum Tower Hospital from January 2012 to December 2017. Outcomes included filter thrombosis, total bleeding events, death.

Results

A total of 202 patients were enrolled in the study and divided into rivaroxaban group and warfarin group. Mean follow-up period of the two groups was 57.4 ± 20.8 and 62.2 ± 23.0 months, respectively. In risk factors for VTE, transient factors (P = 0.008) and history of VTE (P = 0.028) were statistically different between the two groups. A total of 13 (6.4%) patients developed filter complications, of which 4 (3.5%) and 5 (5.7%) patients in rivaroxaban group and warfarin group developed filter thrombosis, respectively, without significant difference (P = 0.690). The total bleeding events in rivaroxaban group, including major bleeding and clinically relevant and non-major (CRNM) bleeding, were significantly lower than that in warfarin group (P = 0.005). Adjusting for hypertension, transient risk factors, history of VTE and cancer, no differences in the hazard ratio for outcomes were notable.

Conclusions

It is necessary to perform a concomitant anticoagulation in patients with non-retrieved filters. Rivaroxaban can be an alternative anticoagulant option for the prevention of filter thrombosis.

Duodenocaval Fistula from an Inferior Vena Cava Filter Perforation

Background

Case report

Conclusions

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Duodenal perforation from IVC filter strut perforation is a rare complication.

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Patients typically present with abdominal pain and upper gastrointestinal bleeding.

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Both endovascular and open surgical techniques can be used to retrieve a filter

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Endovascular retrieval has the potential for development of peri-operative sepsis.

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Open surgical removal is preferred in patients with significant filter dwell time.

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.

Successful retrieval of dislocated inferior vena cava filter using double vascular sheaths docking technology: case report

BACKGROUND

Dislocation of inferior vena cava filter (IVCF) is a rare complication with potential IVC perforation and other life-threatening risks requiring early diagnosis and in-time retrieval. Most of dislocation IVCF in the past have been shelved or removed by open surgery. It is very difficult to retrieve the filters by interventional technology.

CASE PRESENTATION

Here we report a 49-year-old man suffering from dislocation of IVCF implanted due to deep vein thrombosis (DVT) in the right femoral vein. Successful retrieval of the IVCF using double sheaths docking technique was done soon after confirmation of the dislocation. Importance of monitoring and early detection of dislocation of IVCF should be emphasized to avoid further complications.

CONCLUSIONS

The double vascular sheaths docking technique can be considered as a preferential option in difficult operative situation.

Navigating inferior vena cava filters in invasive cardiology procedures: A systematic review

BACKGROUND

Transfemoral venous access (TFV) is the cornerstone of minimally invasive cardiac procedures. Although the presence of inferior vena cava filters (IVCFs) was considered a relative contraindication to TFV procedures, small experiences have suggested safety. We conducted a systematic review of the available literature on cardiac procedural success of TFV with IVCF in-situ.

METHODS

Two independent reviewers searched PubMed, EMBASE, SCOPUS, and Google Scholar from inception to October 2020 for studies that reported outcomes in patients with IVCFs undergoing TFV for invasive cardiac procedures. We investigated a primary outcome of acute procedural success and reviewed the pooled data for patient demographics, procedural complications, types of IVCF, IVCF dwell time, and procedural specifics.

RESULTS

Out of the 120 studies initially screened, 8 studies were used in the final analysis with a total of 100 patients who underwent 110 procedures. The most common IVCF was the Greenfield Filter (36%), 60% of patients were males and the mean age was 67.8 years. The overall pooled incidence of acute procedural success was 95.45% (95% confidence interval = 89.54-98.1) with no heterogeneity (I²  = 0%, p = 1) and there were no reported filter-related complications.

CONCLUSION

This systematic review is the largest study of its kind to demonstrate the safety and feasibility of TFV access in a variety of cardiac procedures in the presence of IVCF.

Prevalence and Characterization of Interaction of Retrievable Inferior Vena Cava Filters with the Spine in Patients Undergoing Complex Filter Removal

PURPOSE

To examine spinal interaction types and prevalence of inferior vena cava (IVC) filters in patients presenting for complex filter removal.

MATERIALS AND METHODS

The records of 447 patients presenting for complex removal of IVC filters were reviewed, including patient demographics, IVC filter dwell time, filter fracture status, and computed tomography (CT) evidence of filter interaction with the spine. Spinal interaction was defined as a filter strut touching or penetrating into the vertebral body or disc. Patients with evidence of filter penetration and spinal interaction had abdominal CT that preceded filter removal assessed by 2 interventional radiologists to categorize the type of spinal interaction, including bony reaction and osteophyte formation.

RESULTS

CT evidence of spinal interaction by the filter was found in 18% of patients (80/447). Interaction with the spine was more common in single point of fixation filters than filters with rails (P = .007) and was more likely in filters with round wires than flat wires (P = .0007). Patients with interaction had longer dwell times (mean [SD] 5.7 [4.46] y) compared with patients without interaction (mean [SD] 3.2 [3.85] y); this relationship was significant (P < .0001). Women were more likely than men to experience filter/spine interaction (P = .04). Filters with spinal interaction were more likely to be fractured (P = .001). Filter interaction was found in 38% (30/78) of patients with symptoms, including chest and back pain, compared with 14% (50/369) of patients without symptoms (P < .0001, odds ratio 3.99).

CONCLUSIONS

Retrievable IVC filters may interact with the spine. These interactions are associated with longer filter dwell times, female sex, and round wire filter construction.

Timing of Prophylactic Inferior Vena Cava Filter Placement and Trauma Outcomes : Does Early Placement Matter?

BACKGROUND

Prophylactic inferior vena cava filters (IVCFs) are often placed in trauma patients who cannot receive prophylactic anticoagulation. IVCFs are utilized in an effort to reduce the risk of acute pulmonary embolism (PE) and mortality. This study aims to investigate whether time-to-filter placement is associated with differences in trauma outcomes.

METHODS

We conducted a single-center retrospective review of adult trauma patients who underwent prophylactic IVCF placement. Patients were divided into 2 groups based on time-to-filter: 0-48 hours and >48 hours. Outcome measures included post-filter deep vein thrombosis (DVT), post-filter PE, in-hospital mortality, and ICU length of stay (ICU-LOS). Significance was defined as P < .05.

RESULTS

During the 6-year study period, 513 patients underwent prophylactic IVCF placement. Both groups were similar with respect to injury severity score (ISS) (P = .540), percent of patients on home anticoagulation (38% and 39%, P = .845), abbreviated injury scale (AIS) by anatomic region (P = .899), and traumatic brain injury (TBI) prevalence (P = .182). Time-to-filter was not associated with significant differences in DVT, PE, or in-hospital mortality (P > .05 for all). Filter placement in the first 48 hours was associated with shorter ICU-LOS and hospital-LOS.

CONCLUSIONS

Currently, there are no investigations in the trauma literature looking at the impact of time-to-filter on complications related to venous thromboembolism and potential survival benefit. Results of this investigation showed that IVCF placement within the first 48 hours was significantly associated with shorter ICU- and hospital- LOS.

Costs and complications of hospital admissions for inferior vena cava filter malfunction

OBJECTIVE

Inferior vena cava filter (IVCF) malfunction can result from penetration, fracture, or migration of the device necessitating retrieval. Endovascular and open retrieval of IVCF have been described in institutional series without comparison. This study examines national hospital admissions for IVCF malfunction and compares the outcomes of open and endovascular retrieval.

METHODS

The National Inpatient Sample database (2016-2017) was reviewed for admissions with International Classification of Diseases, Tenth Revision (ICD-10) codes specific for IVCF malfunction. All ICD-10 procedural codes were reviewed, and patients were divided based on open or endovascular IVCF retrieval. Patient characteristics, outcomes, and costs of hospitalization were compared between the two groups.

RESULTS

There were 665 patients admitted with a diagnosis of IVCF malfunction. Open IVCF retrieval was performed in 100 patients and endovascular removal in 90 patients. Of those undergoing open surgery, 45 patients (45%) required median sternotomy and 55 (55%) required abdominal surgeries. Most patients were white females with a mean age of 54.4 years (range, 49.3-59.6 years) with a history of deep venous thrombosis (55.3%) or pulmonary embolism (31.6%). Most patients with IVCF malfunction were treated in large (81.6%) or urban teaching (94.7%) hospitals situated most commonly in the South (42.1%) and Northeast (29.0%) with no difference in characteristics of the patients or the centers between the two groups. Patients undergoing open IVCF retrieval were more likely to undergo surgery on an elective basis compared with endovascular IVCF retrieval (75.0% vs 11.1%; P < .001). Open IVCF retrieval was associated with a higher likelihood of thromboembolic complication compared with endovascular retrieval (20% vs 0%; P = .04). There was a trend toward higher infectious complications and overall complications with endovascular removal, but this difference did not reach statistical significance. Open retrieval was associated with a mortality of 5.0% compared with no inpatient mortality with endovascular retrieval (P = .33). The mean hospital length of stay was no difference between the two groups. Open retrieval was associated with significantly higher hospital costs than endovascular retrieval ($34,276 vs $19,758; P = .05).

CONCLUSIONS

Filter removal for patients with IVCF malfunction is associated with significant morbidity and cost, regardless of modality of retrieval. The introduction of specific ICD-10 codes for IVCF malfunction allows researchers to study these events. The development of effective tools for outpatient retrieval of malfunctioning IVCF could decrease related hospitalization and have potential savings for the healthcare system.

Contemporary management of chronic indwelling inferior vena cava filters

OBJECTIVE

Despite increasing retrieval rates of the inferior vena cava (IVC) filter, less than one-third are removed within the recommended timeline. Prolonged filter dwell times may increase the technical difficulty of retrieval and filter-related complications. We sought to evaluate the contemporary outcomes of patients with chronic indwelling IVC filters at a tertiary care center.

METHODS

A retrospective analysis was performed from August 2015 through August 2019 of all patients who were referred for removal of a prolonged IVC filter with a dwell time >1 year. Descriptive analysis was used to evaluate patients' characteristics and procedural outcomes, which were reviewed through electronic medical records. Data were expressed as median with interquartile range (IQR) or number and percentage, as appropriate.

RESULTS

A total of 47 patients were identified with a median filter dwell time of 10.0 years (IQR, 6-13 years); 34 patients underwent IVC filter removal, and 13 patients refused retrieval. The median age of patients was 54.9 years (IQR, 42.5-64.0 years); the majority were female (57%) and white (53%). The most common indication for filter placement was high risk despite anticoagulation (49%), followed by venous thromboembolism prophylaxis (21%). The majority of patients were symptomatic (72%). If symptomatic, the most common reason for retrieval was IVC penetration (94%), and the chief complaint was pain (56%). Retrieval success was 97%, with a median length of stay of 0 days. The majority of retrievals were performed through an endovascular approach (97%). There was one postprocedural complication (3%).

CONCLUSIONS

Despite prolonged dwell times, IVC filter retrieval can be performed safely and effectively in carefully selected patients at a tertiary referral center.

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

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

A better inferior vena cava filter retrieval rate: A retrospective study in a single-center institution

Purpose

To determine practice patterns of inferior vena cava filters (IVCFs), retrieval rates, and reasons why retrievable-IVCFs (R-IVCFs) are kept permanent.

Methods

A total of 399 patients who received IVCFs at Third Hospital of Hebei Medical University from January 2017 to December 2017 were registered and retrospectively studied. Date of demographics, baseline medical history, dwell time, reasons why R-IVCFs were kept permanent, and R-IVCFs thrombus were collected.

Results

A total of 399 IVCFs were placed during the study period including 27 permanent IVCFs and 372 R-IVCFs. Among all patients who received R-IVCFs, the mean dwell time was 18.25 ± 16.60 days, follow-up rate was 96.24% (358/372), and 337 R-IVCFs were attempted to be removed. Except one, 336 R-IVCFs were retrieved successfully (336/372, 90.32%). Sixty-four R-IVCFs thrombi were found during retrieval including 53 small-size thrombi (< 1 cm × 1 cm) and 13 large-size thrombi (>1 cm × 1 cm). Fifty-three R-IVCFs with small-size thrombi were removed successfully with no additional treatments. Twelve large-size thrombi were retrieved successfully after catheter-directed thrombolysis.

Conclusions

With good follow-up, the retrieval rate could be improved to 90.32%. The main reasons why R-IVCFs were kept permanent were to avoid losing follow-up and overcome inappropriate selections of indications or IVCF types. And R-IVCFs with thrombus could be removed safely.

An alternative approach to treatment of inferior vena cava filter perforation

Abstract We report a case of inferior vena cava filter perforation immediately after filter implantation, recognized intraoperatively in a patient undergoing laparotomy for resection of locally advanced ovarian cancer. We describe an alternative approach with strut resection, less invasive than filter removal, enabling the device to be maintained and bleeding to be controlled.

Magnification Spot Radiographs Improve Assessment for Inferior Vena Cava Filter Fractures prior to Removal Compared to CT

PURPOSE

To determine if magnification spot radiographs acquired before attempting inferior vena cava (IVC) filter removal have value in the assessment for filter fractures.

MATERIALS AND METHODS

A retrospective review of complex IVC filter removals performed at a tertiary referral center from October 2015 to May 2017 was performed. Magnification spot radiographs (frontal and at least 2 oblique views) were obtained with the fluoroscopic unit in the procedure suite prior to venous access for filter removal. Patients were included in the study if a computed tomography (CT) scan of the abdomen/pelvis before filter removal was available. Ninety-six patients (47 women and 49 men) were included. Most removed filters were the Recovery/G2/G2X/Eclipse/Meridian (n = 28), the Günther Tulip (n = 26), and the Celect/Celect Platinum (n = 22). Blinded review of the pre-procedural CT scans and spot radiographs for the presence of filter fractures was performed by 2 interventional radiologists. Accuracy of each modality was assessed using the status of the explanted filter as the gold standard. Agreement between the 2 readers was assessed with the kappa statistic.

RESULTS

Fractures were present in 27 explanted filters (28%). Accuracy of CT was 88% and 68% for readers 1 and 2, respectively, which increased to 98% and 97% with magnification spot radiographs. The kappa statistic was 0.12 for CT and 0.97 for spot radiographs.

CONCLUSIONS

Magnification spot radiographs acquired before attempting IVC filter removal improve detection of filter fractures and agreement among interventional radiologists. Therefore, these should be performed routinely to allow for optimal treatment planning.

Impact of Dwell Time of Retrievable IVC Filters on IVC Lumen Diameter: A Series of 36 Cases

BACKGROUND

Inferior vena cava (IVC) filters are effective in preventing pulmonary embolism in patients at risk. This study aimed to investigate whether the dwell time of retrievable IVC filters have impact on IVC lumen diameter.

METHODS

The clinical data of 36 patients treated with retrievable IVC filters from January 2016 to November 2018 were retrospectively collected. A total of 33 filters were successfully removed. At times of filter placement and removal, the IVC lumen diameter (at upper, middle, and lower levels of the filter), distance between the filter upper end and the right renal vein opening, and degree of filter tilt were measured.

RESULTS

IVC filters were placed because of deep vein thrombosis in the lower limbs after fractures in 26 patients. The median dwell time of the IVC filters was 18 days. From the time of filter placement to that of removal, the IVC diameter decreased significantly at the middle (28.07 ± 5.92 vs. 25.73 ± 7.33 mm, P = 0.002) and lower levels (27.48 ± 4.73 vs. 26.36 ± 4.72 mm, P = 0.003) of the filters. No significant difference was noticed in the IVC diameter at the upper levels of the filters (27.78 ± 6.43 vs. 27.11 ± 6.63 mm, P = 0.082). Positive correlation was noticed between filter dwell time and IVC diameter changes at the upper (r = 0.381, P = 0.029) and middle (r = 0.555, P = 0.001) levels of the filters. No significant change was noticed in the distance from the filter upper end to the right renal vein opening and the degree of filter tilt.

CONCLUSIONS

Retrievable IVC filters are associated with IVC stenosis. The severity of IVC stenosis is positively correlated with the dwell time of filters.

Guidewire Loop Dissection Technique for Filter Strut Endothelialization

Complex inferior vena cava (IVC) filter retrieval was usually in need of advanced techniques. Filter strut endothelialization without tilt of the filter was still one of the challenges. Therefore, we would like to describe the guidewire loop dissection technique, which required no extra equipment, to solve problem. A 53-year-old male had IVC filter for 8 months. Venogram showed no tilt of the apex and endothelialization of struts. The hook was snared but the filter cannot be retrieved. A fine guidewire was then advanced and formed a loop between the strut and the caval wall. With traction applied, the guidewire peeled the struts off the caval wall, resulting in the dissection of strut endothelialization. In the end, the filter was retrieved without injuring IVC. This technique was a feasible option for such circumstance.

Steady Flow in a Patient-Averaged Inferior Vena Cava-Part I: Particle Image Velocimetry Measurements at Rest and Exercise Conditions

PURPOSE

Although many previous computational fluid dynamics (CFD) studies have investigated the hemodynamics in the inferior vena cava (IVC), few studies have compared computational predictions to experimental data, and only qualitative comparisons have been made. Herein, we provide particle image velocimetry (PIV) measurements of flow in a patient-averaged IVC geometry under idealized conditions typical of those used in the preclinical evaluation of IVC filters.

METHODS

Measurements are acquired under rest and exercise flow rate conditions in an optically transparent model fabricated using 3D printing. To ensure that boundary conditions are well-defined and to make follow-on CFD validation studies more convenient, fully-developed flow is provided at the inlets (i.e., the iliac veins) by extending them with straight rigid tubing longer than the estimated entrance lengths. Velocity measurements are then obtained at the downstream end of the tubing to confirm Poiseuille inflow boundary conditions.

RESULTS

Measurements in the infrarenal IVC reveal that flow profiles are blunter in the sagittal plane (minor axis) than in the coronal plane (major axis). Peak in-plane velocity magnitudes are 4.9 cm/s and 27 cm/s under the rest and exercise conditions, respectively. Flow profiles are less parabolic and exhibit more inflection points at the higher flow rate. Bimodal velocity peaks are also observed in the sagittal plane at the elevated flow condition.

CONCLUSIONS

The IVC geometry, boundary conditions, and infrarenal velocity measurements are provided for download on a free and publicly accessible repository at https://doi.org/10.6084/m9.figshare.7198703 . These data will facilitate future CFD validation studies of idealized, in vitro IVC hemodynamics and of similar laminar flows in vascular geometries.

Long-term complications of inferior vena cava filters

Anticoagulation is the cornerstone for the treatment of deep venous thrombosis and pulmonary embolism. On occasion, this is not possible because of bleeding complications or, rarely, breakthrough pulmonary embolism associated with this treatment method. The development of vena cava interruption in the 1970s was a critical advance in the treatment of these patients. Placement of inferior vena cava (IVC) filters has been steadily increasing since their introduction. Nonetheless, the incidence of complications associated with placement of these devices is largely unknown. Most of the evidence regarding IVC filter complications relies on case reports, with scarce data coming from larger randomized controlled trials. We aimed to present a summary addressing long-term complications of IVC filters as published in recent articles addressing problems such as IVC thrombosis and IVC filter migration, perforation, fracture, embolization, and tilting. We performed a PubMed search and Google Scholar search using different combinations of "long term," "complications," "IVC filter," and "vena cava filter." We reviewed the available English publications and reported the findings in this summary.

Differences in radial expansion force among inferior vena cava filter models support documented perforation rates

OBJECTIVE

Inferior vena cava (IVC) filters are used in patients at risk for pulmonary embolism who cannot be anticoagulated. Unfortunately, these filters are not without risk, and complications include perforation, migration, and filter fracture. The most prevalent complication is filter perforation of the IVC, with incidence varying among filter models. To our knowledge, the mechanical properties of IVC filters have not been evaluated and are not readily available through the manufacturer. This study sought to determine whether differences in mechanical properties are similar to differences in documented perforation rates.

METHODS

The radial expansion forces of Greenfield (Boston Scientific, Marlborough, Mass), Cook Celect (Cook Medical, Bloomington, Ind), and Cook Platinum filters were analyzed with three replicates per group. The intrinsic force exerted by the filter on the measuring device was collected in real time during controlled expansion. Replicates were averaged and significance was determined by calculating analysis of covariance using SAS software (SAS Institute, Cary, NC).

RESULTS

Each filter model generated a significantly different radial expansion force (P < .001), and force was distributed at significantly different rates (P < .001) during expansion. The largest radial expansion force at minimal caval diameter was seen in the Cook Platinum filter, followed by the Cook Celect and Greenfield filters. Radial force dispersion during expansion was greatest in the Cook Celect, followed by the Cook Platinum and Greenfield filters.

CONCLUSIONS

Differences in radial expansion forces among IVC filter models are consistent with documented perforation rates. Cook Celect IVC filters have a higher incidence of perforation compared with Greenfield filters when they are left in place for >90 days. Evaluation of Cook Celect filters yielded a significantly higher radial expansion force at minimum caval diameter, with greater force dispersion during expansion.

Inferior vena cava filter use and patient safety: legacy or science?

There has been a dramatic increase in vena cava filter (VCF) use over the past 20 years in the absence of evidence that filters provide a net patient benefit or are required in most cases. This increase is largely attributable to the availability of retrievable filters and expanded indications, particularly as primary prophylaxis in patients thought to be at high risk of pulmonary embolism. Substantial variability in VCF use, unrelated to patient clinical factors, has been shown between hospitals, from region to region, and among various countries. Despite the lack of direct evidence for the benefit of VCFs for any indication, it is appropriate to insert a retrievable VCF in patients with a recent proximal deep vein thrombosis and an absolute contraindication to therapeutic anticoagulation and then to remove the filter once the bleeding risk decreases and the patient has been anticoagulated. Unfortunately, a high proportion of retrievable filters are not removed, even after the reason for their placement has long passed. Retrievable filters are associated with substantial rates of complications if they are not removed, including penetration of the vena caval wall, fracture and embolization of filter fragments, and caval occlusion. Patient safety priorities and medical-legal concerns mandate careful selection of patients for VCF placement and removal shortly after anticoagulation has been initiated.

Inferior Vena Cava Filters: Current and Future Concepts

The inferior vena cava filter clinical environment is notable for the degree of controversy, uncertainty, and fear associated with these devices by both physicians and the public. This article reviews some of the more important current issues with these devices as well as emerging and future trends.