Placement and Removal of Inferior Vena Cava Filters: National Trends in the Medicare Population

Predictors of endobronchial forceps utilization for inferior vena cava filter retrieval: when snare retrieval fails

BACKGROUND

Endobronchial forceps are commonly used for complex IVC filter removal and after initial attempts at IVC filter retrieval with a snare have failed. Currently, there are no clear guidelines to help distinguish cases where primary removal should be attempted with standard snare technique or whether attempts at removal should directly be started with forceps. This study is aimed to identify clinical and imaging predictors of snare failure which necessitate conversion to endobronchial forceps.

METHODS

Retrospective analysis of 543 patients who underwent IVC filter retrievals were performed at three large quaternary care centers from Jan 2015 to Jan 2022. Patient demographics and IVC filter characteristics on cross-sectional images (degree of tilt, hook embedment, and strut penetration, etc.) were reviewed. Binary multivariate logistic regression was used to identify predictors of IVC filter retrieval where snare retrieval would fail.

RESULTS

Thirty seven percent of the patients (n = 203) necessitated utilization of endobronchial forceps. IVC filter hook embedment (OR:4.55; 95%CI: 1.74-11.87; p = 0.002) and strut penetration (OR: 56.46; 95% CI 20.2-157.7; p = 0.001) were predictors of snare failure. In contrast, total dwell time, BMI, and degree of filter tilt were not associated with snare failure. Intraprocedural conversion from snare to endobronchial forceps was significantly associated with increased contrast volume, radiation dose, and total procedure times (p < 0.05).

CONCLUSION

IVC filter hook embedment and strut penetration were predictors of snare retrieval failure. Intraprocedural conversion from snare to endobronchial forceps increased contrast volume, radiation dose, and total procedure time. When either hook embedment or strut penetration is present on pre-procedural cross-sectional images, IVC filter retrieval should be initiated using endobronchial forceps.

LEVEL OF EVIDENCE

Level 3, large multicenter retrospective cohort.

Retrievable Inferior Vena Cava Filter Trapped Embolus: A Risk Factor of Detachment of Thrombus Analysis Based on a Multicenter Prospective Observational Study

PURPOSE

Up to now, the indications of inferior vena cava filter placement still remain controversial in the academic field. The aim of this study was to determine the risk factors of detachment of thrombus and to evaluate the necessity of inferior vena cava filter placement to prevent fatal pulmonary embolism.

MATERIALS AND METHODS

A total of 2892 patients participated in the multicenter prospective observational study from January 1, 2018, to December 31, 2018, and underwent retrievable inferior vena cava filter (RIVCF) placement in 103 centers in China. The primary endpoint of the study was RIVCF trapped embolus detected by inferior vena cava venography/ultrasound/computed tomography scanning or visible macroscopic thrombus before or during RIVCF retrieval. The relative factors of RIVCF trapped embolus were analyzed accordingly.

RESULTS

The average age of the patients was 61.0 (50.0-71.0) years. Retrievable inferior vena cava filter trapped embolus occurred in 308 patients (10.65%). The fracture location, surgery location, and endovascular intervention differed between RIVCF trapped embolus and non-RIVCF trapped embolus groups (p<0.001, respectively). By multivariate analysis, RIVCF trapped embolus were less common in older patients (odds ratio [OR]=0.998; p<0.001) and more common in patients with below-the-knee fracture (OR=1.093, p=0.038), thigh fracture (OR=1.118, p=0.007), and pelvis surgery (OR=1.067, p=0.016). In addition, compared with patients without endovascular intervention, patients with percutaneous mechanical thrombectomy (PMT) + catheter-directed thrombolysis (CDT) were more prone to develop RIVCF trapped embolus (OR=1.060, p=0.010). However, RIVCF trapped embolus was less common in patients with CDT (OR=0.961, p=0.004).

CONCLUSIONS

Lower limb fracture, pelvis surgery, and PMT + CDT are prone to cause trapped embolus. As a trapped embolus often represents the possibility of severe pulmonary embolism, lower limb fracture, pelvis surgery, and PMT + CDT could be risk factors of fatal pulmonary embolism. Due to the low incidence of trapped embolus, it is not necessary to place filters in elderly patients and CDT-only patients.

CLINICAL IMPACT

The purpose of this paper is to standardize the use of inferior vena cava filter and avoid unnecessary filter implantation through the summary and analysis of a large number of clinical data. At the same time, more attention should be paid to and active treatment should be given to high-risk groups of pulmonary embolism.

Prophylactic Inferior Vena Cava Filters for Venous Thromboembolism in Adults With Trauma: An Updated Systematic Review and Meta-Analysis

Background: Trauma is an independent risk factor for venous thromboembolism (VTE). Due to contraindications or delay in starting pharmacological prophylaxis among trauma patients with a high risk of bleeding, the inferior vena cava (IVC) filter has been utilized as alternative prevention for pulmonary embolism (PE). Albeit, its clinical efficacy has remained uncertain. Therefore, we performed an updated systematic review and meta-analysis on the effectiveness and safety of prophylactic IVC filters in severely injured patients. Methods: Three databases (MEDLINE, EMBASE, and Cochrane) were searched from August 1, 2012, to October 27, 2021. Independent reviewers performed data extraction and quality assessment. Relative risk (RR) at 95% confidence interval (CI) pooled in a randomized meta-analysis. A parallel clinical practice guideline committee assessed the certainty of evidence using the GRADE approach. The outcomes of interest included VTE, PE, deep venous thrombosis, mortality, and IVC filter complications. Results: We included 10 controlled studies (47 140 patients), of which 3 studies (310 patients) were randomized controlled trials (RCTs) and 7 were observational studies (46 830 patients). IVC filters demonstrated no significant reduction in PE and fatal PE (RR, 0.27; 95% CI, 0.06-1.28 and RR, 0.32; 95% CI, 0.01-7.84, respectively) by pooling RCTs with low certainty. However, it demonstrated a significant reduction in the risk of PE and fatal PE (RR, 0.25; 95% CI, 0.12-0.55 and RR, 0.09; 95% CI, 0.011-0.81, respectively) by pooling observational studies with very low certainty. IVC filter did not improve mortality in both RCTs and observational studies (RR, 1.44; 95% CI, 0.86-2.43 and RR, 0.63; 95% CI, 0.3-1.31, respectively). Conclusion: In trauma patients, moderate risk reduction of PE and fatal PE was demonstrated among observational data but not RCTs. The desirable effect is not robust to outweigh the undesirable effects associated with IVC filter complications. Current evidence suggests against routinely using prophylactic IVC filters.

Cost Burden and Cost Influencers of Inferior Vena Cava Filter Placement and Retrieval among Medicare Beneficiaries with Acute Venous Thromboembolism

PURPOSE

To examine the frequency, costs, and cost influencers of inferior vena cava filters (IVCFs) placements and retrievals among a national sample of patients using Medicare data.

MATERIALS AND METHODS

This retrospective cohort study used the U.S. Medicare 100% database, a nationally representative sample of all U.S. patients aged ≥65 years, from 2014 through 2020. Procedures and clinical characteristics were identified from the diagnosis and procedure codes on Medicare claims. Beneficiaries aged ≥65 years with newly diagnosed venous thromboembolism (VTE) were identified and followed to obtain data on IVCF placements and retrievals. Data on the costs of the index IVCF procedures and any subsequent IVCF placements and retrievals were obtained. Multivariate models were used to estimate the impact of patient and clinical characteristics on costs.

RESULTS

Among 501,216 patients with newly diagnosed VTE, 4,995 (1%) received an IVCF placement; of these, 1,215 (24.3%) had a retrieval procedure. Beneficiaries with IVCF placements and retrievals differed from a demographic and clinical perspective than from those without. Costs varied by the site of service, VTE acuity, and VTE type. Cost influencers included age, race, census region, service location, and VTE type.

CONCLUSIONS

IVCF placement costs were driven by baseline patient characteristics (age, race, geographic residence, acute VTE diagnosis, and inpatient site of service), whereas retrieval costs were driven by age and deep vein thrombosis diagnosis. Strategies to mitigate the retrieval costs or the need to retrieve IVCFs may reduce the overall cost burden of IVCFs.

Safety and Success Rates of Excimer Laser Sheath-Assisted Retrieval of Embedded Inferior Vena Cava Filters

IMPORTANCE

Despite historically high rates of use, most inferior vena cava (IVC) filters are not retrieved. The US Food and Drug Administration safety communications recommended retrieval when the IVC filter is no longer indicated out of concern for filter-related complications. However, failure rates are high when using standard techniques for retrieval of long-dwelling filters, and until recently, there have been no devices approved for retrieval of embedded IVC filters.

OBJECTIVE

To evaluate the safety and success of excimer laser sheath-assisted retrieval of embedded IVC filters.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective, multicenter, clinical cohort study of excimer laser sheath-assisted IVC filter retrievals from 7 US sites was conducted between March 1, 2012, and February 28, 2021, among 265 patients who underwent IVC filter retrieval using the laser. Patients were substratified between a high-volume single center and a multicenter data set. A blinded physician committee adjudicated reported complications and their association with use of the laser.

EXPOSURES

Retrieval of IVC filters using excimer laser sheath.

MAIN OUTCOMES AND MEASURES

The primary safety end point was device-related major complication rate (Society of Interventional Radiology categories C to F, which included any adverse event associated with morbidity or disability that increases the level of care, results in hospital admission, or substantially lengthens the hospital stay). The primary success end point was technical success of IVC filter retrieval. The primary end points were compared with literature-derived, meta-analysis-suggested target performance goals.

RESULTS

The single-center experience included 139 participants (mean [SD] age, 52 [16] years; 78 female participants [56.1%]), and the multicenter experience included 126 participants (mean [SD] age, 52 [16] years; 75 female participants [59.5%]). The device-related major complication rate was 2.9% (4 of 139; 95% CI, 0.8%-7.2%; P = .001) for the single-center experience and 4.0% (5 of 126; 95% CI, 1.3%-9.0%; P = .01) for the multicenter experience, both of which were significantly lower than the primary safety performance goal (10%). No major complications were considered to be definitively associated with use of the laser. The technical success rate was 95.7% (133 of 139; 95% CI, 90.8%-98.4%; P = .007) for the single-center experience and 95.2% (120 of 126; 95% CI, 89.9%-98.2%; P = .02) for the multicenter experience, both of which were significantly higher than the primary performance goal (89.4%).

CONCLUSIONS AND RELEVANCE

This cohort study demonstrated high technical success and low complication rates of excimer laser sheath-assisted retrieval of embedded IVC filters in centers with variable case volume and experience, which suggests a wide applicability of the technique with proper training. The excimer laser sheath offers physicians a valuable tool for retrieval of challenging embedded IVC filters.

Effectiveness and Safety of Laser-Assisted Removal of Inferior Vena Cava (IVC) Filters in a Single Tertiary Care Center

INTRODUCTION

Laser sheath-assisted removal of inferior vena cava (IVC) filters with long dwelling time is a technique that utilizes laser-tipped sheaths. The laser light only penetrates vascular tissue by one hundred microns, causing the target tissues to disintegrate into particles less than 5 microns in size. This approach reduces the energy used during difficult retrieval procedures, allowing permanent filters to be removed in less fluoroscopic and procedural time overall.

MATERIALS AND METHODS

The radiology information system and electronic health records were used in this retrospective cohort study to retrieve the data. A total of nine consecutive patients who underwent laser-assisted filter removal utilizing GlideLightTM were included in the study between January 2016 and January 2017. The study took place at King Abdulaziz Medical City in Riyadh. In this study, five patients were male and four were female with ages ranging from 19 to 57 years with a median age of 31.

RESULTS

During the period of the study, a total of nine patients had their IVC filters removed using a laser. The success rate was 100%. The indications were trauma (n=4) followed by deep vein thrombosis (DVT) (n=3) and one patient indication was prolonged immobilization. The dwelling time ranged from seven to 70 months, with a dwelling median of 19 months.

CONCLUSION

A laser sheath might be necessary for closed-cell filters in order to improve the likelihood of a successful and secure retrieval. Technical efficiency, filter type, the necessity of applying a laser sheath based on an open versus closed filter design, dwell times, and unfavorable results. As a result, after typical procedures failed to successfully retrieve IVC filters with long dwell durations, laser-assisted filter removal is thought to be practical and safe.

Changes in national endovascular management of femoropopliteal artery disease: an analysis of the 2011-2019 Medicare data

PURPOSE

Current evidence supports endovascular approaches (including balloon angioplasty, atherectomy, and stenting) for management of femoropopliteal peripheral artery disease (PAD); this study sought to describe national trends in utilization of each intervention.

METHODS

The Medicare Physician/Supplier Procedure Summary dataset containing 100% of part B claims were interrogated for years 2011-2019. Current procedural terminology codes specific for femoropopliteal angioplasty, stenting, and atherectomy were used to create summary statistics for utilization by year, place of service (hospital inpatient, hospital outpatient, and office-based lab), and provider specialty (cardiology, radiology, and surgery).

RESULTS

Atherectomy use increased from 34,732 procedures (33%) in 2011 to 75,435 (53%) in 2019 and became the dominant treatment strategy for femoropopliteal PAD. Relative utilization of stenting (36,793/35% to 28,899/20%) and angioplasty only (34,398/32% to 38,228/27%) decreased concomitantly from 2011 to 2019. Atherectomy use by 2019 was two-fold higher in office-based labs compared with the outpatient hospital setting (44,767 and 20,901, respectively). Treatment strategy varied by provider specialty in 2011 when cardiologists used atherectomy most frequently (17,925/43%), while radiologists used angioplasty alone (5,928/6%) and surgeons stented (18,009/37%) most frequently. By 2019 all specialties utilized atherectomy most frequently (29,564/59% for cardiology, 10,912/58% for radiology, and 33,649/47% for surgery).

CONCLUSION

National approach to endovascular management of femoropopliteal PAD has changed since 2011, towards an implant-free strategy including a multi-fold increase in atherectomy use. Discordant rates of atherectomy between the ambulatory hospital and office-based settings highlight the need for comparative effectiveness studies to guide management.

Population-Based Disparities in Inferior Vena Cava Filter Procedures Among Medicare Enrollees With Acute Venous Thromboembolism

PURPOSE

Venous thromboembolism (VTE) imposes a significant clinical and financial burden on patients and society. Inferior vena cava filters (IVCFs) are considered for patients with absolute contraindications or failures of anticoagulation. However, studies examining the population-based disparities of IVCF placement and retrieval are limited. The association between patient and clinical characteristics in the likelihood of and time to IVCF placement and retrievals in a nationally representative cohort was examined.

METHODS

Medicare patients aged ≥65 years with index VTE claims between 2015 and 2018 were followed through 2019 to identify IVCF placements and retrievals. Rates were compared using survival analysis methods.

RESULTS

Of the 516,978 patients with VTE diagnoses, 5,864 (1.1%) had IVCFs placed, and 1,884 (32.1%) of those underwent retrieval procedures. Placement and retrieval rates varied significantly by demographics, comorbidity burden, and geographic region. From Cox regression, older age (hazard ratio [HR], 1.26; P < .0001), higher baseline comorbidity (Elixhauser) score (HR, 1.07; P < .0001), and outpatient (vs inpatient) site of VTE service (HR, 2.11; P < .0001) were associated with increased frequency of IVCF placement. The rate of retrieval was significantly lower for men (HR, 0.83; P = .0393), patients with higher comorbidity scores (HR, 0.95; P = .0037), and those with outpatient (vs inpatient) VTE sites of service (HR, 0.77; P = .0173). Neither facility- nor county-level characteristics were significantly associated with placements or retrievals.

CONCLUSIONS

This large cohort of Medicare beneficiaries with newly diagnosed VTE demonstrated inequities in IVCF placement and retrieval.

Vena Cava Filters: Toward Optimal Strategies for Filter Retrieval and Patients' Follow-Up

Mortality rates associated with venous thromboembolism (VTE) are high. Inferior vena cava filters (IVCFs) have been frequently placed for these patients as part of their treatment, albeit the paucity of data showing their ultimate efficacy and potential risk of complications. Issues regarding long-term filter dwell time are accounted for in society guidelines. This topic has led to an FDA mandate for filter retrieved as soon as protection from pulmonary embolism is no longer needed. However, even though most are retrievable, some were inadvertently left as permanent, which carries an incremental lifetime risk to the patient. In the past decade, attempts have aimed to determine the optimal time interval during which filter needs to be removed. In addition, distinct strategies have been implemented to boost retrieval rates. This review discusses current conflicts in indications, the not uncommon complications, the rationale and need for timely retrieval, and different quality improvement strategies to fulfill this aim.

Structured team-oriented program to follow patients after vena cava filter placement: a step forward in improving quality for filter retrieval

To reduce inferior vena cava filter (IVCF) related complications, retrieval is recommended whenever possible. Nevertheless, IVCF retrieval rates remain lower than expected, likely due to insufficient follow-up after placement. We evaluated the value of a structured program designed to follow patients by the interventional radiology team up to 5 months after IVCF placement. We prospectively enrolled 366 consecutive patients (mean age 64 ± 17 years; 201 men and 165 women) who benefited from IVCF between March 2015 and February 2020. The program consisted of advising the patient and clinicians to consider IVCF retrieval as soon as possible (standard workflow) and systematically planning an additional follow-up visit at 5-month. Clinical and technical eligibility, as well as technical success for retrieval (TSR) were evaluated. At 5-months, 38 (10.4%) patients were lost to follow-up, and 47 (12.8%) had died. Among survivors, the overall retrieval rate was 58%. The retrieval rates were 83% and 97% for the clinically eligible and technically eligible patients for retrieval, respectively. The 5-month visit enabled 89 additional retrievals (47.8%) compared to the standard workflow. No significant difference was seen in TSR before and after 5 months (p = 0.95). Improved patient tracking with a dedicated IVCF program results in an effective process to identify suitable patients for retrieval and drastically improves retrieval rates in eligible patients. Involving interventionalists in the process improved IVCF patient management.

Laser-Assisted Removal of Embedded Vena Cava Filters: A First-In-Human Escalation Trial in 500 Patients Refractory to High-Force Retrieval

Background

Many patients are subject to potential risks and filter‐related morbidity when standard retrieval methods fail. We evaluated the safety and efficacy of the laser sheath technique for removing embedded inferior vena cava filters.

Methods and Results

Over an 8.5‐year period, 500 patients were prospectively enrolled in an institutional review board–approved study. There were 225 men and 275 women (mean age, 49 years; range, 15–90 years). Indications for retrieval included symptomatic acute inferior vena cava thrombosis, chronic inferior vena cava occlusion, and/or pain from filter penetration. Retrieval was also offered to prevent risks from prolonged implantation and potentially to eliminate need for lifelong anticoagulation. After retrieval failed using 3X standard retrieval force (6–7 lb via digital gauge), treatment escalation was attempted using laser sheath powered by 308‐nm XeCl excimer laser system (CVX‐300; Spectranetics). We hypothesized that the laser‐assisted technique would allow retrieval of >95% of embedded filters with <5% risk of major complications and with lower force. Primary outcome was successful retrieval. Primary safety outcome was any major procedure‐related complication. Laser‐assisted retrieval was successful in 99.4% of cases (497/500) (95% CI, 98.3%–99.9%) and significantly >95% (P<0.0001). The mean filter dwell time was 1528 days (range, 37–10 047; >27.5 years]), among retrievable‐type (n=414) and permanent‐type (n=86) filters. The average force during failed attempts without laser was 6.4 versus 3.6 lb during laser‐assisted retrievals (P<0.0001). The major complication rate was 2.0% (10/500) (95% CI, 1.0%–3.6%), significantly <5% (P<0.0005), 0.6% (3/500) (95% CI, 0%–1.3%) from laser, and all were successfully treated. Successful retrieval allowed cessation of anticoagulation in 98.7% (77/78) (95% CI, 93.1%–100.0%) and alleviated filter‐related morbidity in 98.5% (138/140) (95% CI, 96.5%–100.0%).

Conclusions

The excimer laser sheath technique is safe and effective for removing embedded inferior vena cava filters refractory to high‐force retrieval. This technique may allow cessation of filter‐related anticoagulation and can be used to prevent and alleviate filter‐related morbidity.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT01158482.

Changes in inferior vena cava filter placement and retrieval practice patterns from a population health perspective

PURPOSE

Inferior vena cava (IVC) filters are placed to reduce venous thromboembolism (VTE)-related morbidity and mortality, though the evidence supporting this practice is limited. In 2010, the Food and Drug Administration (FDA) released a device safety advisory due to the risk of filter migration, fracture, and thrombosis with long-term use. The purpose of this study was to evaluate trends and predictors for IVCF placement and retrieval over a 10-year time period from a population health perspective.

MATERIALS AND METHODS

De-identified patient information from the State Inpatient Databases (SID) and the States Ambulatory Surgery and Services Databases (SASD) for Florida and California were used to identify all patients who underwent IVC filter placement from 2005 to 2014 and 2005 to 2011, respectively. Hospital practice patterns were assessed as a function of time as well as IVC filter placement and retrieval volume. Temporal trends were evaluated for statistical significance using the Cochran-Armitage test.

RESULTS

A total of 181,260 IVC filters were placed in 178,327 patients over the study period. IVC filter placements peaked in 2010; following the FDA advisory in 2010, however, IVC filter placements monotonically decreased each subsequent year. The proportion of IVCF placement patients with both acute DVT and PE (17.6% vs 11.8%, P < 0.001) at the time of hospitalization increased; likewise, the proportion of IVCF patients with acute DVT or PE with a concomitant acute contraindication to anticoagulation at the time of hospitalization increased as well following 2010 (17.0% vs 11.9%, P < 0.001). From 2005 to 2014, there was a continual increase in both filter retrieval procedures as well overall percentage of filters retrieved. However, estimated retrieval rates remained low, with a retrieval rate of less than 6% in 2014.

CONCLUSION

Following the FDA warning in 2010, there was a significant decrease in IVC filter placements, with filter placements more frequently performed in patients with poorer health. While retrieval rates increased over time, they remained low.

Cost Analysis of Dialysis Access Maintenance Interventions across Physician Specialties in U.S. Medicare Beneficiaries

Background Dialysis maintenance interventions account for billions of dollars in U.S. Medicare spending and are performed by multiple medical specialties. Whether Medicare costs differ by physician specialty is, to the knowledge of the authors, not known. Purpose To assess patency-adjusted costs of endovascular dialysis access maintenance by physician specialty. Materials and Methods In this retrospective longitudinal cohort study, patients who were beneficiaries of Medicare undergoing their first arteriovenous access placement in 2009 were identified by using billing codes in the 5% Limited Data Set. By tracking their utilization data through 2014, postintervention primary patency and aggregate payments associated with maintenance interventions were calculated. Unadjusted payments per year of access patency gain were compared across physician specialty. A general linear mixed-effects model adjusted for covariates was used, as follows: patient characteristics, access type (fistula vs graft), clinical severity, type of intervention (angioplasty, stent, thrombolysis), clinical location (hospital outpatient vs office-based laboratory), and resource utilization (operating room use, anesthesia use). Results First arteriovenous access was performed in 1479 beneficiaries (mean age, 63 years ± 15 [standard deviation]; 820 men) in 2009. Through 2014, 8166 maintenance interventions were performed in this cohort. Unadjusted mean Medicare payments for each incremental year of patency were as follows: $71 000 for radiologists, $89 000 for nephrologists, and $174 000 for surgeons. Billing for operating room (41.8% [792 of 1895], surgery; 10.2% [277 of 2709], nephrology; and 31.1% [1108 of 3562], radiology) and anesthesia (19.9% [377 of 1895], surgery; 2.6% [70 of 2709], nephrology; 4.7% [170 of 3562], radiology) varied by specialty and accounted for 407% and 132% higher payments, respectively. After adjusting for clinical severity and location, type of intervention, and resource utilization, nephrologists and surgeons had 59% (95% confidence interval: 44%, 73%; P < .001) and 57% (95% confidence interval: 43%, 72%; P < .001) higher payments, respectively, for the same patency gain compared with radiologists. Operating room use and anesthesia services were major drivers of higher cost, with 407% (95% confidence interval: 374%, 443%; P < .001) and 132% (95% confidence interval: 116%, 150%; P < .001) higher costs, respectively. Conclusion Patency-adjusted payments for hemodialysis access maintenance differed by physician specialty, driven partly by discrepant rates of billing for operating room and anesthesia use. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by White in this issue.

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.

Interventional Radiology Therapy: Inferior Vena Cava Filter and Catheter-based Therapies

Endovascular management of pulmonary embolism can be divided into therapeutic and prophylactic treatments. Prophylactic treatment includes inferior vena cava filter placement, whereas endovascular therapeutic interventions include an array of catheter-directed therapies. The indications for both modalities have evolved over the last decade as new evidence has become available.

Changing trends in inferior vena cava filter indication for venous thromboembolism over the last two decades: a retrospective observational study

BACKGROUND

The present study aimed to evaluate changes in the incidence, patients' profile and indications of inferior vena cava filters at a single center over the past two decades.

METHODS

We retrospectively analyzed 187 consecutive patients with a venous thromboembolism requiring a filter at a tertiary hospital between 1999-2018. Within this period the availability of retrievable filters (since 2007) and the withdrawal of filter indication for recurrent venous thromboembolism from guidelines (since 2008) may have contributed to change practice patterns. Patients' profile, filter indication and survival were compared between decades (1999-2008 vs. 2009-2018).

RESULTS

The filter insertion rate doubled (60 vs. 127 cases) over 2009-2018. In this later period there was an unexpected rise (15 vs. 68 cases, P<0.001) of patients with isolated pulmonary embolism as baseline venous thromboembolism episode, without other relevant changes in patients' profile or survival. Regarding indications, there was an increase in filters for bleeding risk (23 vs. 45) and a reduction for venous thromboembolism recurrence (20 vs. 7), but also an unexpected increase of cases for bleeding (15 vs. 72). Among the 116 retrievable filters indicated for a temporary cause, 70 (60.3%) were finally not removed, being persistence of filter indication (n=33, 47.1%) the most common cause.

CONCLUSIONS

The number of filters inserted at our institution has raised over the last two decades. This increase was partly unexpected and perhaps related to the availability of retrievable filters. Unfortunately these devices remain frequently non-removed being persistence of the indication the most frequent cause.

Use and Removal of Inferior Vena Cava Filters in Patients With Acute Brain Injury

Background

Few data exist regarding the rate of inferior vena cava (IVC) filter retrieval among brain-injured patients.

Methods

We conducted a retrospective cohort study using inpatient claims between 2009 and 2015 from a nationally representative 5% sample of Medicare beneficiaries. We included patients aged ≥65 years who were hospitalized with acute brain injury. The primary outcome was the retrieval of IVC filter at 12 months and the secondary outcomes were the association with 30-day mortality and 12-month freedom from pulmonary embolism (PE). We used Current Procedural Terminology codes to ascertain filter placement and retrieval and International Classification of Diseases, Ninth Revision, Clinical Modification codes to ascertain venous thromboembolism (VTE) diagnoses. We used standard descriptive statistics to calculate the crude rate of filter placement. We used Cox proportional hazards analysis to examine the association between IVC filter placement and mortality and the occurrence of PE after adjustment for demographics, comorbidities, and mechanical ventilation. We used Kaplan-Meier survival statistics to calculate cumulative rates of retrieval 12 months after filter placement.

Results

Among 44 641 Medicare beneficiaries, 1068 (2.4%; 95% confidence interval [CI], 2.3%-2.5) received an IVC filter, of whom 452 (42.3%; 95% CI, 39.3%-45.3) had a diagnosis of VTE. After adjusting for demographics, comorbidities, and mechanical ventilation, filter placement was not associated with a reduced risk of mortality (hazard ratio [HR], 1.0; 95% CI, 0.8-1.3) regardless of documented VTE. The occurrence of pulmonary embolism at 12 months was associated with IVC filter placement (HR, 3.19; 95% CI, 1.3-3.3) in the most adjusted model. The cumulative rate of filter retrieval at 12 months was 4.4% (95% CI, 3.1%-6.1%); there was no significant difference in retrieval rates between those with and without VTE.

Conclusions

In a large cohort of Medicare beneficiaries hospitalized with acute brain injury, IVC filter placement was uncommon, but once placed, very few filters were removed. IVC filter placement was not associated with a reduced risk of mortality and did not prevent future PE.

The role of an IVC filter retrieval clinic-A single center retrospective analysis

Background:

Inferior vena cava (IVC) filter placement still plays an essential role in preventing pulmonary embolism (PE) in patients with contraindications to anticoagulant therapy. However, IVC filter placement does have long-term risks which may be mitigated by retrieving them as soon as clinically acceptable. A dedicated IVC filter clinic provides a potential means of assuring adequate follow-up and retrieval.

Aim:

To assess the efficacy of our Inferior vena cava (IVC) filter retrieval clinic at improving the rate of patient follow-up, effective filter management, and retrieval rates.

Materials and Methods:

During the period of August 2017 through July 2018, 70 IVC filters were placed at our institution, and these patients were automatically enrolled into our IVC filter retrieval clinic for quarterly follow-up. We retrospectively reviewed data including appropriateness for removal at 3 months, overall retrieval rates, removal technique(s) employed, and technical success.

Results:

62.9% of the potentially retrievable filters were removed during the study period. The technical success of extraction, using a combination of standard and advanced techniques, was 91.7%. Overall, 15% of the patients were lost to follow-up.

Conclusion:

Our findings add to the growing body of literature to support the need for a robust IVC filter retrieval clinic to ensure adequate follow-up and timely retrieval of IVC filters.

Bidirectional loop-snare technique for adherent inferior vena cava filter retrieval

Placement of a Günther Tulip Inferior Vena Cava (IVC) Filter™ (Cook, Bloomington, IN, USA) is an alternative treatment option to prevent pulmonary embolism in patients in whom anticoagulation therapy is contraindicated. Most patients require filter placement for only short periods, after which it can be retrieved. IVC filter retrieval becomes more difficult as the indwelling time increases. We developed a new method to retrieve the Günther Tulip IVC Filter™, namely, the bidirectional loop-snare technique (BLT). The key to the BLT procedure is to use 2 snares from both the jugular and femoral access routes. The jugular snare catches the filter hook and the femoral snare relieves the adhesion between the filter leg and IVC wall. Pulling from both the jugular and femoral ends increases the power to retrieve the IVC filter, and leads to successful filter retrieval. <Learning objective: An inferior vena cava (IVC) filter is placed in patients with a risk of pulmonary embolism. Most patients require filter placement for only short periods, after which it can be retrieved. Occasionally, IVC filter retrieval is difficult because of long-term placement. We developed a novel, simple method for filter retrieval, using a bidirectional approach and two snares simultaneously.>.

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.

Disparities over Time in Volume, Day of the Week, and Patient Complexity between Paracentesis and Thoracentesis Procedures Performed by Radiologists versus Those Performed by Nonradiologists

PURPOSE

To compare the disparities between the paracenteses and thoracenteses performed by radiologists with those performed by nonradiologists over time. Variables included the volume of procedures, the days of the week, and the complexity of the patient's condition.

MATERIALS AND METHODS

Using carrier claims files for a 5% national sample of Medicare beneficiaries from 2004 to 2016, paracentesis and thoracentesis examinations were retrospectively classified by physician specialty (radiologist vs nonradiologist), day of the week (weekday vs weekend), and the complexity of the patient's condition (using Charlson comorbidity index scores). The Pearson chi-square and independent samples t-test were used for statistical analysis.

RESULTS

Between 2004 and 2016, the proportion of all paracentesis and thoracentesis procedures performed by radiologists increased from 70% to 80% and from 47% to 66%, respectively. Although radiologists increasingly performed more of both services on both weekends and weekdays, the share performed by radiologists was lower on weekends. For most of the first 9 years across the study period, radiologists performed paracentesis in patients with more complex conditions than those treated by nonradiologists, but the complexity of patients' conditions was similar during recent years. For thoracentesis, the complexity of patients' conditions was similar for both specialty groups across the study period.

CONCLUSIONS

The proportion of paracentesis and thoracentesis procedures performed in Medicare beneficiaries by radiologists continues to increase, with radiologists increasingly performing most of both services on weekends. Nonetheless, radiologists perform disproportionately more on weekdays than on weekends. Presently, radiologists and nonradiologists perform paracentesis and thoracentesis procedures in patients with similarly complex conditions. These interspecialty differences in timing and complexity of the patient's condition differ from those recently described for several diagnostic imaging services, reflecting the unique clinical and referral patterns for invasive versus diagnostic imaging services.

Prophylactic inferior vena cava filters for operative pelvic fractures: a twelve year experience

INTRODUCTION

Conflicting evidence exists regarding the role of inferior vena cava filters (IVCFs) in the prevention of pulmonary embolism. The aim of this study was to review an institutional policy of prophylactic IVCF placement in all operative pelvic and acetabular fractures as a means of preventing PE by comparing it to a historical prepolicy period of significantly less aggressive IVCF placement.

METHODS

The trauma registry of a single level 1 trauma center was retrospectively queried for all pelvic or acetabular fractures for the prepolicy and intervention periods as defined as January 2003-December 2008 and January 2009-December 2014, respectively-yielding 231 patients for analysis. The primary and secondary outcomes measured were the incidence of PE and deep vein thrombosis.

RESULTS

The rate of prophylactic IVCF insertion significantly increased during the study period (p < 0.001). The incidence of pulmonary embolism (1.8% vs. 5.1%, p = 0.351) and DVT (19.3% vs. 10.3%, p = 0.231) were not significantly different when comparing the prepolicy and intervention cohorts. In patients with operative fractures, a nonsignificant trend of increasing incidence of DVTs was appreciated in patients with a prophylactic IVCF versus those without prophylactic IVCF (13 vs. 2, p = 0.222).

DISCUSSION

A policy of increased use of prophylactic IVCFs in patients with operative pelvic and acetabular fractures failed to reduce the incidence of PE or DVT. In contrast, several case reports and institutional series have published several risks associated with IVCF placement including failure to retrieve temporary IVCF.

CONCLUSION

The benefit of prophylactic IVCF in this patient population is unclear.

A Multicenter Trial of Vena Cava Filters in Severely Injured Patients

BACKGROUND

Whether early placement of an inferior vena cava filter reduces the risk of pulmonary embolism or death in severely injured patients who have a contraindication to prophylactic anticoagulation is not known.

METHODS

In this multicenter, randomized, controlled trial, we assigned 240 severely injured patients (Injury Severity Score >15 [scores range from 0 to 75, with higher scores indicating more severe injury]) who had a contraindication to anticoagulant agents to have a vena cava filter placed within the first 72 hours after admission for the injury or to have no filter placed. The primary end point was a composite of symptomatic pulmonary embolism or death from any cause at 90 days after enrollment; a secondary end point was symptomatic pulmonary embolism between day 8 and day 90 in the subgroup of patients who survived at least 7 days and did not receive prophylactic anticoagulation within 7 days after injury. All patients underwent ultrasonography of the legs at 2 weeks; patients also underwent mandatory computed tomographic pulmonary angiography when prespecified criteria were met.

RESULTS

The median age of the patients was 39 years, and the median Injury Severity Score was 27. Early placement of a vena cava filter did not result in a significantly lower incidence of symptomatic pulmonary embolism or death than no placement of a filter (13.9% in the vena cava filter group and 14.4% in the control group; hazard ratio, 0.99; 95% confidence interval [CI], 0.51 to 1.94; P = 0.98). Among the 46 patients in the vena cava filter group and the 34 patients in the control group who did not receive prophylactic anticoagulation within 7 days after injury, pulmonary embolism developed in none of those in the vena cava filter group and in 5 (14.7%) in the control group, including 1 patient who died (relative risk of pulmonary embolism, 0; 95% CI, 0.00 to 0.55). An entrapped thrombus was found in the filter in 6 patients.

CONCLUSIONS

Early prophylactic placement of a vena cava filter after major trauma did not result in a lower incidence of symptomatic pulmonary embolism or death at 90 days than no placement of a filter. (Funded by the Medical Research Foundation of Royal Perth Hospital and others; Australian New Zealand Clinical Trials Registry number, ACTRN12614000963628.).

State-Level Variation in Inferior Vena Cava Filter Utilization Across Medicare and Commercially Insured Populations

OBJECTIVE. Recent research on inferior vena cava (IVC) filter utilization in the United States has largely focused on national aggregate Medicare datasets, showing recent declines. Whether these national Medicare trends are generalizable across regions and payer populations is unknown. We studied recent state-level variation in IVC filter utilization across both Medicare and private insurance populations. MATERIALS AND METHODS. Using large individual beneficiary claims-level Medicare research identifiable files and a proprietary U.S. research database of the commercially insured population, we identified all billed IVC filter placement procedures performed between 2009 and 2015. We compared population-adjusted utilization rates by state and payer type. RESULTS. Between 2009 and 2015, IVC filter utilization across the United States declined by 36.3% (from 177.9 to 113.3 procedures per 100,000 beneficiaries) in the Medicare population and by 26.6% (from 32.7 to 24.0 procedures per 100,000 beneficiaries) in the privately insured population. For the Medicare population, state-level utilization rates varied 5.2-fold, from 48.4 to 251.3 procedures per 100,000 beneficiaries in Alaska and New Jersey, respectively. For the private insurance population, rates varied 5.5-fold, from 10.8 to 59.5 procedures per 100,000 beneficiaries in Oregon and Michigan, respectively. Nationally, utilization in the Medicare population was 5.0 times higher than that in the private insurance population (range by state, from 2.0 times higher in Hawaii to 11.1 times higher in Utah). Despite the national decline, utilization in Medicare and private insurance populations increased in five and seven states, respectively. State-level IVC filter utilization rates for the Medicare population correlated strongly with those for the privately insured population (r = 0.74; p < 0.001). In both the Medicare and privately insured populations, utilization rates correlated moderately with beneficiary age (r = 0.44 and r = 0.50, respectively; p < 0.001 for both). CONCLUSION. IVC filter utilization rates vary dramatically by state and payer population, and they likely depend in part on the age of the covered population. To better identify demographic and socioeconomic drivers of utilization, future research should prioritize nonaggregate multipayer claims-level approaches.

Transcatheter Dialysis Conduit Procedures: Changing National and State-Level Medicare Use Patterns over 15 Years

PURPOSE

To evaluate the changing use of transcatheter hemodialysis conduit procedures.

METHODS

Multiple Centers for Medicare & Medicaid Services datasets were used to assess hemodialysis conduit angiography. Use was normalized per 100,000 beneficiaries and stratified by specialty and site of service.

RESULTS

From 2001 to 2015, hemodialysis angiography use increased from 385 to 1,045 per 100,000 beneficiaries (compound annual growth rate [CAGR], +7.4%)]. Thrombectomy use increased from 114 to 168 (CAGR, +2.8%). Angiography and thrombectomy changed, by specialty, +1.5% and -1.3% for radiologists, +18.4% and +14.4% for surgeons, and +24.0% and +17.7% for nephrologists, respectively. By site, angiography and thrombectomy changed +29.1% and +20.7% for office settings and +0.8% and -2.4% for hospital settings, respectively. Radiologists' angiography and thrombectomy market shares decreased from 81.5% to 37.0% and from 84.2% to 47.3%, respectively. Angiography use showed the greatest growth for nephrologists in the office (from 5 to 265) and the greatest decline for radiologists in the hospital (299 to 205). Across states in 2015, there was marked variation in the use of angiography (0 [Wyoming] to 1173 [Georgia]) and thrombectomy (0 [6 states] to 275 [Rhode Island]). Radiologists' angiography and thrombectomy market shares decreased in 48 and 31 states, respectively, in some instances dramatically (eg, angiography in Nevada from 100.0% to 6.7%).

CONCLUSIONS

Dialysis conduit angiography use has grown substantially, more so than thrombectomy. This growth has been accompanied by a drastic market shift from radiologists in hospitals to nephrologists and surgeons in offices. Despite wide geographic variability nationally, radiologist market share has declined in most states.

A survey of vascular specialists' practice patterns of inferior vena cava filter placement and retrieval

OBJECTIVES

The placement of inferior vena cava filters (IVCF) continues to rise. Vascular specialists adopt different practices based on local expertise. This study was performed to assess the attitudes of vascular specialists towards the placement and retrieval of IVCF.

METHODS

An online survey of 28 questions related to practice patterns regarding IVCF was administered to 1429 vascular specialists. Vascular specialists were categorized as low volume if they place less than three IVCF per month and high volume if they place at least three IVCF per month. The responses of high volume and low volume were compared using two-sample t-tests and Chi-square tests.

RESULTS

A total of 259 vascular specialists completed the survey (18% response rate). There were 191 vascular surgeons (74%) and 68 interventional radiologists (26%). The majority of responders were in academic practice (67%) and worked in tertiary care centers (73%). The retrievable IVCF of choice was Celect (27%) followed by Denali (20%). Forty-two percent used a temporary IVCF and left it in situ instead of using a permanent IVCF. Eighty-two percent preferred placing the tip of the IVCF at or just below the lowest renal vein. Thirty-one percent obtained a venous duplex of the lower extremities prior to retrieval while 24% did not do any imaging. There were 132 (51%) low volume vascular specialists and 127 (49%) high volume vascular specialists. Compared to low volume vascular specialists, significantly more high volume vascular specialists reported procedural times of less than 30 min for IVCF retrieval (57% vs. 42%, P = 0.026). There was a trend for high volume to have fewer unsuccessful attempts at IVCF retrieval but that did not reach statistical significance ( P = .061). High volume were more likely to have attempted multiple times to retrieve an IVCF (66% vs. 33%, P < .001), and to have used bronchoscopy forceps (32% vs. 14%, P = .001) or a laser sheath (14% vs. 2%, P < .001) for IVCF retrieval. In general, vascular specialists were not comfortable using bronchoscopy forceps (65%) or a laser sheath (82%) for IVCF retrieval.

CONCLUSIONS

This study underscores significant variability in vascular specialists practice patterns regarding IVCF. More studies and societal guidelines are needed to define best practices.

Factors Affecting Inferior Vena Cava Filter Retrieval: A Review

Objective:

Over the last 2 decades, there has been an exponential rise in placement of retrievable inferior vena cava (IVC) filters, while the retrieval rate has remained steadily low. Approaches to increasing filter retrieval rates have been extensively studied.

Conclusion:

This review presents an up-to-date review of reported data-driven variables that affect retrieval rates of IVC filters, with a focus on clinical, technical, and process factors.

Persistently low inferior vena cava filter retrieval rates in a population-based cohort

BACKGROUND

Practice patterns associated with inferior vena cava (IVC) filter placement have seen considerable variation in the last decade. We used a statewide administrative database to examine trends in IVC filter placement and retrieval in the general population.

METHODS

We reviewed Florida state inpatient and ambulatory surgery databases from 2004 to 2014. International Classification of Diseases, Ninth Revision diagnosis and procedure codes and Current Procedural Terminology codes were searched for patients undergoing inpatient or outpatient IVC filter placement, and each patient was longitudinally tracked to the time of inpatient or outpatient filter retrieval. For inpatient filter placements, associated diagnoses were reviewed to identify indications for placement. Univariate and multivariate logistic regression models were constructed to identify factors associated with improved retrieval rates.

RESULTS

During the 11-year period, 131,791 IVC filter placements were identified, with a 50% increase from 2004 to 2010 and a 24% decline from 2010 to 2014. Median age at filter placement was 71 years (interquartile range, 57-81 years). Mean follow-up after filter placement was 17.3 ± 25.5 months. Only 8637 filters (6.6%) were retrieved. The annual retrieval rate trended upward, from 3.4% in 2004 to 8.5% in 2013 (P < .001). Median filter dwell time was 96.5 days (interquartile range, 44-178 days). Diagnoses associated with filter placement included venous thromboembolism (75.9%), trauma (35.0%), hemorrhage (29.9%), malignant disease (29.4%), and stroke (5.1%). Retrieval rates were highest in younger patients (34.0% in patients younger than 20 years) and lowest in Medicare patients (2.5%). In a multivariate logistic regression model, Medicare was associated with decreased retrieval rates (odds ratio, 0.33; 95% confidence interval, 0.31-0.35; P < .001) after adjusting for age and associated diagnoses. Weaker risk factors included increased age, white race, and diagnoses of deep venous thrombosis, pulmonary embolism, and malignant disease. A trauma diagnosis was associated with improved retrieval. To further investigate the Medicare effect, a propensity score-matched model was created to better account for confounding effects. In this model, Medicare persisted as a risk factor for decreased filter retrieval (odds ratio, 0.43; 95% confidence interval, 0.40-0.46; P < .001).

CONCLUSIONS

IVC filter placements, after a substantial increase between 2004 and 2010, have been declining since 2010. Retrieval rates in the general population are steadily improving but continue to lag behind those described in center-specific literature. Increased age and Medicare as the primary payer are the strongest risk factors for lack of filter retrieval. Widespread improvements on a national scale are needed to improve the appropriateness of filter placements and to enhance filter retrieval rates.

Tulip piercing the aorta: a rare case of IVC filter aortic perforation and obstruction

Prolonged implantation of inferior vena cava (IVC) filters can lead to significant morbidity. We present a 25-year-old man with antiphospholipid syndrome, lower extremity deep vein thrombosis, and subsequent Gunther-Tulip IVC filter placement. More than 10 years following IVC filter placement he developed progressive abdominal and back pains. Cross-sectional angiography revealed that he had a chronic IVC occlusion, and IVC filter limb extensions into the infrarenal aorta, lumbar spine, and right psoas muscle. The IVC filter limb protruding into the aorta had also pierced through the backwall to lead to partial lumen thrombosis and obstruction. The patient underwent a transabdominal exposure of the infrarenal IVC and aorta, filter explantation and aortic patch angioplasty repair. This case highlights the severity of aortic injury from a protruding IVC filter limb that necessitated open aortic repair. Improved selection, monitoring and retrieval stewardship of IVC filters can help reduce the risk of unintended aortic complications.

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

PURPOSE

To analyze relevant metrics involved in Denali Vena Cava Filter placement via different venous access sites.

MATERIALS AND METHODS

Patients 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.

RESULTS

Seventy-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.

CONCLUSIONS

Both 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.

Day of Week, Site of Service, and Patient Complexity Disparities in Musculoskeletal MRI Interpretations by Radiologists Versus Nonradiologists

OBJECTIVE

Although most musculoskeletal MRI examinations are interpreted by radiologists, some nonradiologists provide interpretations as well. We aimed to study day of week (weekday vs weekend), site of service, and patient complexity differences between radiologists and nonradiologists interpreting lower extremity MRI examinations on Medicare beneficiaries.

MATERIALS AND METHODS

Using fee-for-service carrier claims for a 5% sample of Medicare beneficiaries nationally from 2012 through 2014, we identified all lower extremity joint MRI examinations. Services were classified by physician specialty, day of week, and site of service. Charlson comorbidity index (CCI) values were calculated for all patients. Chi-square statistical testing was performed.

RESULTS

Of all 125,800 billed lower extremity joint MRI examinations, 118,295 (94.0%) were performed on weekdays and 7505 (6.0%) on weekends. Of the weekday examinations, radiologists interpreted 85,991 (83.3%) and nonradiologists 17,260 (16.7%). Of the weekend examinations, radiologists interpreted 6212 (92.8%) and nonradiologists 485 (7.2%). Of examinations performed in inpatient hospital and emergency department settings, radiologists interpreted 6499 (99.2%) and nonradiologists 51 (0.8%). Of the examinations on the most clinically complex patients (CCI ≥ 3), radiologists interpreted 4228 (90.2%) and nonradiologists 461 (9.8%). All interspecialty differences were statistically significant (p < 0.001).

CONCLUSION

In the Medicare population, radiologists interpret most lower extremity joint MRI examinations. Compared with nonradiologists, radiologists disproportionately provide services on weekends, in the highest acuity settings, and on the most clinically complex patients. To promote patient access and minimize disparities, future pay-for-performance metrics should consider temporal, acuity, and complexity parameters.

Surveillance, anticoagulation, or filter in calf vein thrombosis

OBJECTIVE

This study compared the efficacy and complication rates of inferior vena cava (IVC) filters for calf vein thrombosis (CVT) vs conservative treatment with or without anticoagulation.

METHODS

Vascular laboratory studies of patients who had an isolated CVT (anterior and posterior tibialis, peroneal, soleal, and gastrocnemius veins) from April 2009 to January 2014 were retrospectively analyzed from a single institution. Of 647 patients with isolated CVT, 285 (44%) received an IVC filter, and 362 (56%) received medical treatment alone (38.9% surveillance, 11.6% prophylactic anticoagulation, and 49.4% therapeutic anticoagulation). Univariate, multivariate, propensity matching, and Kaplan-Meier analyses were performed on abstracted data, which included, but was not limited to, risk factors, treatment modalities, venous thromboembolism (VTE) complications (defined as propagation of deep vein thrombosis [DVT] or pulmonary embolism [PE]), bleeding complications, and IVC filter-related complications (ie, filter tilting >15°, perforation >3 mm, fracture, migration >10 mm).

RESULTS

The overall incidence of PE in was 2.5% in the IVC filter group and 3.3% in the medical group (P = .27). The overall incidence of VTE complications (propagation of DVT, PE) was 35% for the surveillance group without anticoagulation, 30% in patients treated with prophylactic anticoagulation, and 10% in patients treated with therapeutic anticoagulation (P = .0003). Only a minority of patients underwent duplex ultrasound imaging after filter insertion. In the IVC filter group, the most common reasons that contraindicated anticoagulation were bleeding (35%) or recent surgery (27%). The number of IVC filter-related complications in the IVC filter group was 29 (10%). Because the IVC filter group was older (mean age, 65 vs 61 years, P = .004) and more likely to have a history of thromboembolic events (56% vs 16%, P < .0001), and malignancy (49% vs 28%, P < .0001), propensity analyses were performed yielding a homogenous cohort. The overall complication and thromboembolic rates did not differ for muscular (soleal, gastrocnemius) vs tibial DVTs (anterior, posterior, peroneal veins).

CONCLUSIONS

The use of anticoagulation in patients with CVT significantly decreases the rates of VTE complications. The use of IVC filters in this study was associated with a 10% complication rate and did not significantly reduce the incidence of PE. Nevertheless, given the overall low rates of PE and the higher risk of VTE in patients who receive filters, the decision to insert a filter in patients with calf CVT should be individualized.

An Informatics Approach to Facilitate Clinical Management of Patients With Retrievable Inferior Vena Cava Filters

OBJECTIVE

Long indwelling times for inferior vena cava (IVC) filters that are used to prevent venous thromboembolism can result in complications. To improve care for patients receiving retrievable IVC filters, we developed and evaluated an informatics-based initiative to facilitate patient tracking, clinical decision-making, and care coordination.

MATERIALS AND METHODS

A semiautomated filter-tracking application was custom-built to query our radiology information system to extract and transfer key data elements related to IVC filter insertion procedures into a database. A web-based interface displayed key information and facilitated communication between the interventional radiology clinical team and referring physicians. A set of filter management options was provided depending on each patient's clinical condition. The system was launched in April 2016. Using retrospective observational cohort methods, we compared filter retrieval rates during a test period from July through December 2016 with a control period of the same 6 months in 2015.

RESULTS

System development required approximately 100 hours of development time. Two hundred ninety-three IVC filter placements and 83 filter retrievals were tracked during the study periods. The overall filter retrieval rate was 23% in the control period and 34% in the test period. Mean times from filter placement to retrieval in the control and test periods were not significantly different (88.9 and 102.7 days, respectively; p = 0.32).

CONCLUSION

A semiautomated approach to tracking patients with IVC filters can facilitate care coordination and clinical decision-making for a device with known potential complications. Similar applications designed to improve provider communication and documentation of filter management plans, including appropriateness for retrieval, can be replicated.

Endobronchial Forceps-Assisted and Excimer Laser-Assisted Inferior Vena Cava Filter Removal: The Data, Where We Are, and How It Is Done

The recognition of inferior vena cava filter related complications has motivated increased attentiveness in clinical follow-up of patients with inferior vena cava filters and has led to development of multiple approaches for retrieving filters that are challenging or impossible to remove using conventional techniques. Endobronchial forceps and excimer lasers are tools for designed to aid in complex inferior vena cava filter removals. This article discusses endobronchial forceps-assisted and excimer laser-assisted inferior vena cava filter retrievals.

Trends in vena cava filter insertions and "prophylactic" use

BACKGROUND

Prophylactic vena cava filter (VCF) use in patients without venous thromboembolism is common practice despite ongoing controversy. Thorough analysis of the evolution of this practice is lacking. We describe trends in VCF use and identify events associated with changes in practice.

METHODS

Using the National Inpatient Sample, we conducted a retrospective observational study of U.S. adult hospitalizations from 2000 to 2014. Trends in prophylactic VCF insertion were analyzed both across the entire study population and within subgroups according to trauma status and type of concurrent surgery. Annual percentage change (APC) was calculated, and trends were analyzed using Poisson regression.

RESULTS

Among 461,904,314 adult inpatients (median [interquartile range] age, 58.1 [38.5-74.3] years; 39.6% male), the incidence of VCF insertion increased rapidly at first (from 0.19% to 0.35%; APC, 11.2%; 95% confidence interval [CI], 10.3%-12.2%; P < .001), then at a slower rate after the publication of the Prévention du Risque d'Embolie Pulmonaire par Interruption Cave 2 (PREPIC2) trial in 2005 (from 0.35% to 0.42%; APC, 4.4%; 95% CI, 2.8%-6.0%; P < .001), and it began decreasing after the 2010 Food and Drug Administration (FDA) safety alert (from 0.42% to 0.32%; APC, -5.5%; 95% CI, -6.5% to -4.6%; P < .001). The percentage of total VCFs that had a prophylactic indication increased quickly before publication of the PREPIC2 trial (APC, 19.5%; 95% CI, 17.9%-21.0%; P < .001), increased at a slower rate after publication in 2005 (APC, 4.4%; 95% CI, 2.6%-6.2%; P < .001), and dropped after the FDA safety alert, stabilizing at 18.5% for the last 3 years (APC, -0.3%; 95% CI, -2.2% to 1.7%; P = .8). Subgroups most associated with prophylactic VCF insertion were operative trauma (odds ratio [OR], 10.9; 95% CI, 10.2-11.7), orthopedic surgery (OR, 4.7; 95% CI, 4.3-5.2), and neurosurgical procedures (OR, 3.9; 95% CI, 3.6-4.2). All groups except orthopedic surgery experienced a deceleration in prophylactic VCF growth after the publication of PREPIC2. Meanwhile, the FDA safety alert was associated with a decrease in prophylactic VCF insertions for all groups except other major surgery.

CONCLUSIONS

Whereas publication of the PREPIC2 trial led to a deceleration in prophylactic VCF insertion growth, the FDA alert had a bigger impact, leading to declining rates of prophylactic VCF use. Further investigations of prophylactic insertion of VCF in trauma, orthopedic, and neurosurgical patients are needed to determine whether current levels of use are justified.

Retrospective analysis of outcomes following inferior vena cava (IVC) filter placement in a managed care population

The role of inferior vena cava filter (IVC) filters for prevention of pulmonary embolism (PE) is controversial. This study evaluated outcomes of IVC filter placement in a managed care population. This retrospective cohort study evaluated data for individuals with Humana healthcare coverage 2013-2014. The study population included 435 recipients of prophylactic IVC filters, 4376 recipients of therapeutic filters, and two control groups, each matched to filter recipients. Patients were followed for up to 2 years. Post-index anticoagulant use, mortality, filter removal, device-related complications, and all-cause utilization. Adjusted regression analyses showed a positive association between filter placement and anticoagulant use at 3 months: odds ratio (ORs) 3.403 (95% CI 1.912-6.059), prophylactic; OR, 1.356 (95% CI 1.164-1.58), therapeutic. Filters were removed in 15.67% of prophylactic and 5.69% of therapeutic filter cases. Complication rates were higher with prophylactic procedures than with therapeutic procedures and typically exceeded 2% in the prophylactic group. Each form of filter placement was associated with increases in all-cause hospitalization (regression coefficient 0.295 [95% CI 0.093-0.498], prophylactic; 0.673 [95% CI 0.547-0.798], therapeutic) and readmissions (OR 2.444 [95% CI 1.298-4.602], prophylactic; 2.074 [95% CI 1.644-2.616], therapeutic). IVC filter placement in this managed care population was associated with increased use of anticoagulants and greater healthcare utilization compared to controls, low rates of retrieval, and notable rates of device-related complications, with effects especially pronounced in assessments of prophylactic filters. These findings underscore the need for appropriate use of IVC filters.

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.

Are too many inferior vena cava filters used? Controversial evidences in different clinical settings: a narrative review

The use of inferior vena cava filters to prevent pulmonary embolism is increasing mainly because of indications that appear to be unclearly codified and recommended. The evidence supporting this approach is often heterogeneous, and mainly based on observational studies and consensus opinions, while the insertion of an IVC filter exposes patients to the risk of complications and increases health care costs. Thus, several proposed indications for an IVC filter placement remain controversial. We attempt to review the proof on the efficacy and safety of IVC filters in several "special" clinical settings, and assess the robustness of the available evidence for any specific indication to place an IVC filter.