Clinical experience with retrievable vena cava filters: results of a prospective observational multicenter study

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.

Changes in perfusion angiography after IVC filter placement and retrieval

Inferior vena cava (IVC) filters are posited to effect flow dynamics, causing turbulence, vascular remodeling and eventual thrombosis; however, minimal data exists evaluating hemodynamic effects of IVC filters in vivo. The purpose of this study was to determine differences in hemodynamic flow parameters acquired with two-dimension (2D)-perfusion angiography before and after IVC filter placement or retrieval. 2D-perfusion images were reconstructed retrospectively from digital subtraction angiography from a cohort of 37 patients (13F/24M) before and after filter placement (n = 18) or retrieval (n = 23). Average dwell time was 239.5 ± 132.1 days. Changes in the density per pixel per second within a region of interest (ROI) were used to calculate contrast arrival time (AT), time-to-peak (TTP), wash-in-rate (WIR), and mean transit time (MTT). Measurements were obtained superior to, inferior to, and within the filter. Differences in hemodynamic parameters before and after intervention were compared, as well as correlation between parameters versus filter dwell time. A P value with Bonferroni correction of <.004 was considered statistically significant. After placement, there was no difference in any 2D-perfusion variable. After retrieval, ROIs within and inferior to the filter showed a significantly shorter TTP (1.7 vs 1.4 s, P = .004; 1.5 vs 1.3 s, P = .001, respectively) and MTT (1.7 vs 1.4 s, P = .003; 1.5 vs 1.2 s, P = .002, respectively). Difference in variables showed no significant correlation when compared to dwell time. 2D-perfusion angiography is feasible to evaluate hemodynamic effects of IVC filters in vivo. TTP and MTT within and below the filter after retrieval were significantly changed, without apparent correlation to dwell time, suggesting a functional hemodynamic delay secondary to filter presence.

Clinical outcomes of retrievable inferior vena cava filters for venous thromboembolic diseases

Aim: To identify literature evidence assessing retrievable inferior vena cava filter (rIVCF) for venous thromboembolic diseases. Methods: A systematic literature search was conducted to identify relevant references from the mainstay English and Chinese bibliographic databases (search period: January 2003 to October 2019). Results: 80 original studies with 11,413 patients were included in this review. The success rates of deploying the six types of rIVCFs ranged from 98.4 to 100.0%. Denali had the highest retrieval success rate (95.4-97.6%). The incidence rates of fracture and perforation associated with retrieving the six rIVCFs were less than 2%. Conclusion: The approved rIVCF had comparable clinical profiles, except that Denali was easier to be retrieved than other rIVCF.

Clinical evaluation of retrievable inferior vena cava filters for the prevention of pulmonary thromboembolism

BACKGROUND AND AIMS

Inferior vena cava filters (IVCFs) have been reported to cause chronic complications. Recently, retrievable IVCFs (r-IVCF) have been increasingly used to prevent acute pulmonary thromboembolism (PTE) and allow retrieval upon reduction of PTE risk. However, the outcomes of their use in Japan remain unknown.

METHODS

This study retrospectively investigated the acute PTE relapse prevention rate, IVCF retrieval attempt rate, retrieval success rate, and long-term prognosis of 197 patients who underwent r-IVCF insertion at our hospital between 2010 and 2018.

RESULTS

Subjects had a mean age of 68 years and a male-to-female ratio of 1:1. After r-IVCF insertion, the acute PTE prevention rate was 99.5%. The r-IVCF retrieval rate was 55% (108 patients), with a success rate of 99% (107 patients). r-IVCF retrieval was not attempted in 89 cases due to advanced cancer or poor prognosis (41%), loss to follow-up (32%), and long-term indwelling IVCF (17%). The retrieval group had an average observation period of 36 months, with their anticoagulation therapy continuation, PTE recurrence, and deep vein thrombosis (DVT) recurrence rates being 64%, 3%, and 4%, respectively. The non-retrieval group had a mean observation period of 21 months, with their anticoagulation continuation, PTE recurrence, and DVT recurrence rates being 78%, 3%, and 15%, respectively. DVT recurrence rates increased significantly in the non-retrieval group (p < 0.01). Moreover, 65% of all DVTs occurred centrally from the femoral veins, among which 9% were contraindicated for anticoagulation therapy.

CONCLUSIONS

IVCF placement significantly prevented acute PTE but promoted recurrent DVTs when not retrieved after risk reduction. Hence, to increase recovery rates, IVCFs be promptly removed when no longer necessary.

Non-retrieved inferior vena cava filters: causes and long-term follow-up

BACKGROUND

Temporary inferior vena cava (IVC) filters are not always retrieved. Information about long-term outcomes of patients with indwelling filters is scarce. Aims of our study were to assess reasons that preclude retrieval of temporary IVC filters and long-term outcomes and causes of death in patients with indwelling filters.

MATERIALS AND METHODS

Retrospective observational study including all consecutive patients undergoing IVC filter insertion from January 2009 through December 2018. Patients with permanent filters and those with temporary filters not retrieved were followed from insertion until June 2020.

RESULTS

We included 271 patients with a mean age of 63.8 years. The main indication for filter insertion was acute venous thromboembolism and contraindication for anticoagulation (83%). The filter was deemed as permanent in 24.4% of patients and temporary in 75.6%. Sixty six percent of temporary filters were retrieved; the main cause of non-retrieval was lack of planning / follow-up (57.9%). One hundred twelve patients (41.3%) remained with indwelling filters. After follow-up, 54.5% were alive and 45.5% had died, with a median survival time of 6.19 (95% CI, 2.63-9.75) years. The most frequent cause of death during follow-up was cancer (49%). The frequency of anticoagulant therapy was similar in both groups (57.4%% versus 54.9%).

CONCLUSIONS

The main preventable cause of non-retrieval of temporary IVC filters was lack of planning / follow-up. Structured follow-up programs should be implemented to increase retrieval rates. In patients with indwelling filters, the main cause of death was cancer and extended anticoagulation was not associated with survival.

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.

Practice Variation in Vena Cava Filter Use Among Trauma Centers in the National Trauma Database

BACKGROUND

Agreement regarding indications for vena cava filter (VCF) utilization in trauma patients has been in flux since the filter's introduction. As VCF technology and practice guidelines have evolved, the use of VCF in trauma patients has changed. This study examines variation in VCF placement among trauma centers.

MATERIALS AND METHODS

A retrospective study was performed using data from the National Trauma Data Bank (2005-2014). Trauma centers were grouped according to whether they placed VCFs during the study period (VCF+/VCF-). A multivariable probit regression model was fit to predict the number of VCFs used among the VCF+ centers (the expected [E] number of VCF per center). The ratio of observed VCF placement (O) to expected VCFs (O:E) was computed and rank ordered to compare interfacility practice variation.

RESULTS

In total, 65,482 VCFs were placed by 448 centers. Twenty centers (4.3%) placed no VCFs. The greatest predictors of VCF placement were deep vein thrombosis, spinal cord paralysis, and major procedure. The strongest negative predictor of VCF placement was admission during the year 2014. Among the VCF+ centers, O:E varied by nearly 500%. One hundred fifty centers had an O:E greater than one. One hundred sixty-nine centers had an O:E less than one.

CONCLUSIONS

Substantial variation in practice is present in VCF placement. This variation cannot be explained only by the characteristics of the patients treated at these centers but could be also due to conflicting guidelines, changing evidence, decreasing reimbursement rates, or the culture of trauma centers.

Vena Cava Filter Use in Trauma and Rates of Pulmonary Embolism, 2003-2015

Importance

Vena cava filter (VCF) placement for pulmonary embolism (PE) prophylaxis in trauma is controversial. Limited research exists detailing trends in VCF use and occurrence of PE over time.

Objective

To analyze state and nationwide temporal trends in VCF placement and PE occurrence from 2003 to 2015 using available data sets.

Design, Setting, and Participants

A retrospective trauma cohort study was conducted using data from the Pennsylvania Trauma Outcome Study (PTOS) (461 974 patients from 2003 to 2015), the National Trauma Data Bank (NTDB) (5 755 095 patients from 2003 to 2014), and the National (Nationwide) Inpatient Sample (NIS) (24 449 476 patients from 2003 to 2013) databases.

Main Outcomes and Measures

Temporal trends in VCF placement and PE rates, filter type (prophylactic or therapeutic), and established predictors of PE (obesity, pregnancy, cancer, deep vein thrombosis, major procedure, spinal cord paralysis, venous injury, lower extremity fracture, pelvic fracture, central line, intracranial hemorrhage, and blood transfusion). Prophylactic filters were defined as VCFs placed before or without an existing PE, while therapeutic filters were defined as VCFs placed after a PE.

Results

Of the 461 974 patients in PTOS, the mean (SD) age was 47.2 (26.4) and 61.6% (284 621) were men; of the 5 755 095 patients in NTDB, the mean age (SD) was 42.0 (24.3) and 63.7% (3 666 504) were men; and of the 24 449 476 patients in NIS, the mean (SD) age was 58.0 (25.2) and 49.7% (12 160 231) were men. Of patients receiving a filter (11 405 in the PTOS, 71 029 in the NTDB, and 189 957 in the NIS), most were prophylactic VCFs (93.6% in the PTOS, 93.5% in the NTDB, and 93.3% in the NIS). Unadjusted and adjusted temporal trends for the PTOS and NTDB showed initial increases in filter placement followed by significant declines (unadjusted reductions in VCF placement rates, 76.8% in the PTOS and 53.3% in the NTDB). The NIS demonstrated a similar unadjusted trend, with a slight increase and modest decline (22.2%) in VCF placement rates over time; however, adjusted trends showed a slight but significant increase in filter rates. Adjusted PE rates for the PTOS and NTDB showed significant initial increases followed by slight decreases, with limited variation during the declining filter use periods. The NIS showed an initial increase in PE rates followed by a period of stagnation.

Conclusions and Relevance

Despite a precipitous decline of VCF use in trauma, PE rates remained unchanged during this period. Taking this association into consideration, VCFs may have limited utility in influencing rates of PE. More judicious identification of at-risk patients is warranted to determine individuals who would most benefit from a VCF.

Optional Vena Cava Filters: What, Why, and When

Optional vena cava filters can used to provide either short-term or permanent protection from pulmonary embolism. These devices have recently become available for clinical use in the United States. However, there remains a paucity of data about these devices and their outcomes. This article reviews current and future devices, the rationale behind non-permanent caval filtration, and the generally accepted guidelines for their clinical application.

Utility of Retrievable Vena Cava Filters and Mechanical Thrombectomy in the Endovascular Management of Acute Deep Venous Thrombosis

Endovascular interventions of symptomatic deep venous thrombosis (DVT) using various therapeutic modalities, such as thrombolysis, mechanical thrombectomy, and inferior vena cava (IVC) filter placement, have received increased focus owing in part to advances in catheter-based interventional technologies. Although systemic anticoagulation remains the primary treatment modality in DVT, catheter-based interventions can provide rapid removal of large thrombus burden and possibly preserve venous valvular function in patients with symptomatic DVT. This article reviews current endovascular treatment strategies for acute DVT. Specifically, the utility of mechanical thrombectomy along with various temporary IVC filters in the setting of DVT is examined. Lastly, an illustrative case of acute DVT that was treated with endovascular intervention with IVC filter placement is presented.

Evidence-Based Evaluation of Inferior Vena Cava Filter Complications Based on Filter Type

Many inferior vena cava (IVC) filter types, along with their specific risks and complications, are not recognized. The purpose of this study was to evaluate the various FDA-approved IVC filter types to determine device-specific risks, as a way to help identify patients who may benefit from ongoing follow-up versus prompt filter retrieval. An evidence-based electronic search (FDA Premarket Notification, MEDLINE, FDA MAUDE) was performed to identify all IVC filter types and device-specific complications from 1980 to 2014. Twenty-three IVC filter types (14 retrievable, 9 permanent) were identified. The devices were categorized as follows: conical (n = 14), conical with umbrella (n = 1), conical with cylindrical element (n = 2), biconical with cylindrical element (n = 2), helical (n = 1), spiral (n = 1), and complex (n = 1). Purely conical filters were associated with the highest reported risks of penetration (90-100%). Filters with cylindrical or umbrella elements were associated with the highest reported risk of IVC thrombosis (30-50%). Conical Bard filters were associated with the highest reported risks of fracture (40%). The various FDA-approved IVC filter types were evaluated for device-specific complications based on best current evidence. This information can be used to guide and optimize clinical management in patients with indwelling IVC filters.

Observations on failed retrieval of optional inferior vena cava filters

PURPOSE

To evaluate causes of failed optional inferior vena cava filter (IVCF) retrievals.

METHODS

Single-center retrospective study.

RESULTS

IVCF retrievals were attempted in 26/211 (12%) patients at a mean 42.9 days. There were 9 failures (all OptEase) due to: inability to snare the hook (n=5), noncollapsible IVCF (n=3), and unusual procedural pain (n=1). Median duration of retrieved IVCFs was 31 days compared to 53 days for failures (P<.05). IVCFs aligned with the IVC's cephalocaudal axis were retrieved in 13/16 cases, while misaligned IVCFs were retrieved 4/10 cases (P<.05).

CONCLUSION

Filter duration and misalignment were significantly associated with retrieval failures.

A fractured inferior vena cava filter strut migrating to the left pulmonary artery

Inferior vena cava filters are increasingly used in patients with recurrent venous thromboembolism who are contraindicated to anticoagulation. Migration of a broken strut to the pulmonary artery is a very rare complication of these filters. We report the case of an 83-year-old female who experienced this complication with the migratory strut remaining in the same position for years. This case provides evidence that such filters probably have higher rates of complications than what has been thought that remain asymptomatic. The indications and the management of complications of such devices need to be studied further.

Geometric changes of the inferior vena cava in trauma patients subjected to volume resuscitation

OBJECTIVE

Dynamic changes in anatomic geometry of the inferior vena cava from changes in intravascular volume may cause passive stresses on inferior vena cava filters. In this study, we aim to quantify variability in inferior vena cava dimensions and anatomic orientation to determine how intravascular volume changes may impact complications of inferior vena cava filter placement, such as migration, tilting, perforation, and thrombosis.

METHODS

Retrospective computed tomography measurements of major axis, minor axis, and horizontal diameters of the inferior vena cava at 1 and 5 cm below the lowest renal vein in 58 adult trauma patients in pre-resuscitative (hypovolemic) and post-resuscitative (euvolemic) states were assessed in a blinded fashion by two independent readers. Inferior vena cava perimeter, area, and volume were calculated and correlated with caval orientation.

RESULTS

Mean volumes of the inferior vena cava segment on pre- and post-resuscitation scans were 9.0 cm(3) and 11.0 cm(3), respectively, with mean percentage increase of 48.6% (P < 0.001). At 1 cm and 5 cm below the lowest renal vein, the inferior vena cava expanded anisotropically, with the minor axis expanding by an average of 48.7% (P < 0.001) and 30.0% (P = 0.01), respectively, while the major axis changed by only 4.2% (P = 0.11) and 6.6% (P = 0.017), respectively. Cross-sectional area and perimeter at 1 cm below the lowest renal vein expanded by 61.6% (P < 0.001) and 10.7% (P < 0.01), respectively. At 5 cm below the lowest renal vein, the expansion of cross-sectional area and perimeter were 43.9% (P < 0.01) and 10.7% (P = 0.002), respectively. The major axis of the inferior vena cava was oriented in a left-anterior oblique position in all patients, averaging 20° from the horizontal plane. There was significant underestimation of inferior vena cava maximal diameter by horizontal measurement. In pre-resuscitation scans, at 1 cm and 5 cm below the lowest renal vein, the discrepancy between the horizontal and major axis diameter was 2.1 ± 1.2 mm (P < 0.001) and 1.7 ± 1.0 mm (P < 0.001), respectively, while post-resuscitation studies showed the same underestimation at 1 cm and 5 cm below the lowest renal vein to be 2.2 ± 1.2 mm (P < 0.01) and 1.9 ± 1.0 mm (P < 0.01), respectively.

CONCLUSIONS

There is significant anisotropic variability of infrarenal inferior vena cava geometry with significantly greater expansive and compressive forces in the minor axis. There can be significant volumetric changes in the inferior vena cava with associated perimeter changes but the major axis left-anterior oblique caval configuration is always maintained. These significant dynamic forces may impact inferior vena cava filter stability after implantation. The consistent major axis left-anterior oblique obliquity may lead to underestimation of the inferior vena cava diameter used in standard anteroposterior venography, which may influence initial filter selection.

Comparison of complication rates associated with permanent and retrievable inferior vena cava filters: a review of the MAUDE database

PURPOSE

To compare the safety of permanent and retrievable inferior vena cava (IVC) filters by reviewing the U.S. Food and Drug Administration Manufacturer and User Facility Device Experience (MAUDE) database.

MATERIALS AND METHODS

The MAUDE database was reviewed from January 1, 2009, to December 31, 2012. Product class search criteria were "filter, intravascular, cardiovascular." Type of device used and specific adverse events (AEs) were recorded.

RESULTS

For the period January 2009-December 2012, 1,606 reported AEs involving 1,057 IVC filters were identified in the MAUDE database . Of reported AEs, 1,394 (86.8%) involved retrievable inferior vena cava filters (rIVCFs), and 212 (13.2%) involved permanent inferior vena cava filters (pIVCFs) (P < .0001). Reported AEs included fracture, migration, limb embolization, tilt, IVC penetration, venous thromboembolism and pulmonary embolism, IVC thrombus, and malfunctions during placement. Each specific AE was reported with significantly higher frequency in rIVCFs compared with pIVCFs. The most common reported complication with rIVCFs was fracture, whereas the most commonly reported complications with pIVCFs were placement malfunctions. For rIVCFs, the most commonly reported AE varied depending on filter brand.

CONCLUSIONS

The MAUDE database reveals that complications occur with significantly higher frequency with rIVCFs compared with pIVCFs. This finding suggests that the self-reported complication rate with rIVCFs is significantly higher than the self-reported complication rate with pIVCFs.

Pulmonary embolism after total joint arthroplasty: cost and effectiveness of four treatment modalities

Pulmonary embolism (PE) treatment relies on therapeutic anticoagulation and may be associated with severe complications. Inferior vena cava filters (IVCFs) are used as an alternative/adjunct to anticoagulation. In this study we evaluate 4 treatment protocols for clinical efficacy and cost. We reviewed over 27,000 total joint arthroplasty (TJA) patients. We retrospectively identified 294 patients with a documented, symptomatic PE within 90 days of surgery. All patients were treated with warfarin postoperatively. In addition, for the acute management, patients were divided into four treatment groups: (1) IVCF only, (2) IVCF with heparin, (3) heparin only and (4) no treatment. Complication rates, hospital stay and PE recurrence are reported. Among patients who received warfarin, IVCF was associated with fewer complications and lower overall hospital costs compared to the use of heparin for the treatment of PE after TJA.

Decision analysis of retrievable inferior vena cava filters in patients without pulmonary embolism

BACKGROUND

Retrievable filters are increasingly implanted for prophylaxis in patients without pulmonary embolism (PE) but who may be at transient risk. These devices are often not removed after the risk of PE has diminished. This study employs decision analysis to weigh the risks and benefits of retrievable filter use as a function of the filter's time in situ.

METHODS

Medical literature on patients with inferior vena cava (IVC) filters and a transient risk of PE were reviewed. Weights reflecting relative severity were assigned to each adverse event. The risk score was defined as weight × occurrence rate and combines the frequency and severity for each type of adverse event. The value function in the decision model combines the following risks: (1) risk in situ; (2) risk of removal, and (3) relative risk without filters. A decreasing net risk score represents a net expected benefit, and an increasing net risk score indicates the expected harm outweighs the expected benefit.

RESULTS

The net risk score reaches its minimum between day 29 and 54 postimplantation. This is consistent with an increasing net risk associated with continued use of retrievable IVC filters in patients with transient, reversible risk of PE. The results were insensitive to reasonable variations in the assessed weights and adverse event occurrence rates.

CONCLUSIONS

For patients with retrievable IVC filters in whom the transient risk of PE has passed, quantitative decision analysis suggests the benefit/risk profile begins to favor filter removal between 29 and 54 days after implantation.

Risk factors for venous thromboembolism in critically ill nontrauma surgical patients who cannot receive chemical prophylaxis

BACKGROUND

We sought to identify independent predictors of venous thromboembolism in critically ill general surgery patients who cannot receive chemical prophylaxis in order to identify those who may benefit from aggressive screening and/or prophylactic inferior vena cava filter placement.

METHODS

Nontrauma patients in the surgical intensive care unit were prospectively followed for 2 years. Patients who had contraindications to prophylactic anticoagulation and received routine screening duplex examinations were included. Data regarding lower-extremity deep venous thrombosis or pulmonary embolism (PE) rates, past medical history (PMH), surgeries, and transfusions were collected. Logistic regression was used to identify independent predictors of lower-extremity deep venous thrombosis or PE (venous thromboembolism) with a P < .05.

RESULTS

Data were complete for 204 patients. Twenty (9.8%) patients developed venous thromboembolism. Independent predictors of venous thromboembolism included postoperative blood product requirements (odds ratio = 1.04 per unit), a PMH of PE (OR = 10.1), and a PMH of renal insufficiency (odds ratio = 5.1).

CONCLUSIONS

Aggressive screening and/or prophylactic inferior vena cava filter may be considered when prophylactic anticoagulation is prohibited in patients with increased postoperative transfusion requirements or a PMH of either PE or renal insufficiency.

Improving retrieval rates for retrievable inferior vena cava filters

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

Retrievable inferior vena cava filters for venous thromboembolism

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

Risk factors for venous thromboembolism in critically ill trauma patients who cannot receive chemical prophylaxis

BACKGROUND

Standard venous thromboembolism (VTE) prevention for critically ill trauma patients includes sequential compression devices and chemical prophylaxis. When contraindications to anticoagulation are present, prophylactic inferior vena cava filters (IVCF) may be used to prevent pulmonary emboli (PE) in high-risk patients, but specific indications are lacking. We sought to identify independent predictors of VTE in critically-ill trauma patients who cannot receive chemical prophylaxis in order to identify a subset of patients who may benefit from aggressive screening and/or prophylactic IVCF placement.

METHODS

All trauma patients in the surgical ICU from 2008 to 2009 were prospectively followed. Patients with an ICU length of stay ≥2 days who had contraindications to prophylactic anticoagulation were included. Screening duplex exams were obtained within 48 h of admission and then weekly. CT-angiography for PE was obtained if clinically indicated. Patients were excluded if they did not receive a duplex or if they had a post-injury VTE prior to ICU admission. Data regarding VTE rates (lower extremity [LE] DVT or PE), demographics, past medical history (PMH), injuries, and surgeries were collected. Univariate and multivariable analyses were performed to identify independent predictors of VTE with a p<0.05.

RESULTS

411 trauma patients with a mean age of 48 (SD 22) years and 8 (SD 9) ICU days were included. 72% were male and the mean ISS was 22 (SD 13). 30 (7.3%) patients developed VTE: 28 (6.8%) with LEDVT and 2 (0.5%) with PE. Risk factors for VTE with a p<0.2 on univariate analysis included: PMH of DVT, injury severity score (ISS), extremity fractures (Fx), and a pelvis or LE extremity Fx repair. After logistic regression, only PMH of DVT (OR=22.6) and any extremity Fx (OR=2.4) remained as independent predictors.

CONCLUSION

VTE occur in 7% of critically injured trauma patients who cannot receive chemical prophylaxis. Aggressive screening and/or prophylactic IVCF placement may be considered in patients with a PMH of DVT or extremity fractures when anticoagulation is prohibited.

IVC filter limb penetration of the caval wall during retroperitoneal surgery/lymph node dissection

Optional inferior vena cava (IVC) filters are being increasingly used for protection against pulmonary embolism in patients with deep vein thrombosis where anticoagulation is contraindicated. We describe two cases during retroperitoneal surgery where the IVC filters were found to have perforated the cava wall and were subsequently removed intra-operatively. Cava wall penetration by filter limbs poses a significant danger during retroperitoneal lymph node dissection and filters should be removed preoperatively.

Retrievable vena cava filters: a clinical review

Venous thromboembolism (VTE), including deep vein thrombosis and pulmonary embolism (PE), is a major cause of morbidity and mortality. Parenteral anticoagulant treatment with full-dose unfractioned heparin, low-molecular-weight-heparin, or fondaparinux, followed by oral treatment with the vitamin K antagonists, is recommended for the majority of patients. However, in the presence of contraindications to anticoagulant treatment, bleeding complications during antithrombotic treatment, or VTE recurrences despite optimal anticoagulation, interruption of the inferior vena cava with a filter is a potential option aimed to prevent life-threatening PE. Currently, the vast majority of filters implanted worldwide are of the permanent type, but their use is associated with a number of long term complications. Non-permanent filters represent an important alternative, and in particular retrievable filters are an attractive option because they may be either left in place permanently or safely retrieved after a quite long period when they become unnecessary. In this review, we summarize the currently available literature regarding retrievable vena cava filters and we discuss current evidences on their efficacy and safety. Moreover, the appropriate indications for their use in daily clinical practice are reviewed.

The Role for Prophylaxis Inferior Vena Cava Filters in Patients Undergoing Bariatric Surgery: Replacing Anecdote with Evidence

The number of patients choosing surgical alternatives for weight reduction continues to increase. Despite common thromboembolic preventive methods, which include perioperative subcutaneous heparin injections, early mobilization, and sequential compression devices, postoperative deep vein thrombosis/pulmonary embolism remains a devastating complication after bariatric surgery. The role prophylactic inferior vena cava (IVC) filters may play in bariatric surgery remains controversial, and this article aims to address the risks and benefits of prophylactic IVC filters in high-risk bariatric patients and suggest an evidence-based algorithm for their use.

The use of retrievable inferior vena cava filters in the trauma population

OBJECTIVE

To determine if the use of retrievable filters resulted in an increase in the placement of inferior vena cava (IVC) filters in trauma patients.

DESIGN

All patients who underwent IVC filter placement at Yale-New Haven Hospital, New Haven, Connecticut, USA between the years 1999 and 2004.

SETTING

Academic, level 1 trauma centre.

PATIENTS

Included in the present study were 202 trauma patients and 676 nontrauma patients.

INTERVENTION

IVC filter placement.

MAIN OUTCOME MEASURE

Demographics, indications, complication rates and type of IVC filters placed in trauma patients versus nontrauma patients were evaluated.

RESULTS

The present study determined 45.4% (n=92) of trauma patients undergoing IVC filter placement were younger than 40 years of age, compared with 7.8% (n=53) of nontrauma patients. The most common indication for IVC filter placement in trauma patients was prophylaxis (n=162, 80.2%), while in the nontrauma patients only 11.4% (n=77) of patients underwent prophylactic filter placement. The number of retrievable filters used in trauma patients increased from 46.7% in 2001, the year they became available, to 78.9% in 2004. The use of retrievable filters similarly increased in the nontrauma population from 35.9% in 2001 to 78.3% in 2004. Approximately 24% of the patients that underwent IVC filter placement at Yale-New Haven Hospital were categorized as trauma patients. The complication rate for this time period was 0.5% (n=1) in the trauma population versus 3.7% (n=26) in the nontrauma population.

CONCLUSION

The overall number of IVC filters placed in trauma patients did not dramatically increase with the introduction of retrievable filters, suggesting that the indications for the use of IVC filters have not changed.

The use of prophylactic inferior vena cava filters in trauma patients: a systematic review

INTRODUCTION

Pulmonary embolisms (PE) are an often preventable cause of late morbidity and mortality after trauma. Although there is evidence for the use of therapeutic inferior vena cava (IVC) filters (defined as IVC filters implanted in those with proven deep venous thrombosis [DVT] in order to prevent PE), there is not as much evidence to support the use of prophylactic IVC filters. Thus, we undertook a systematic review of the literature to assess the following in prophylactic IVC filters: efficacy in PE reduction, prevalence of filter-related complications and the indications for use.

MATERIALS AND METHODS

After screening 249 studies, 24 studies met inclusion criteria for qualitative synthesis.

RESULTS

Overall, the literature is supportive of the use of prophylactic IVC filters in high-risk poly-trauma patients who may have contraindications to DVT prophylaxis. Filter-associated complications are uncommon and, when they do occur, tend to be of limited clinical significance. Limited data, mostly in the form of case series, supports a reduction in PE and PE-related mortality. There has been increasing use of retrievable filters as well as the ability to safely retrieve them at longer intervals.

CONCLUSION

Despite the addition of a few matched-control studies, the literature is still plagued by a lack of high quality data, and therefore the true efficacy of prophylactic IVC filters for prevention of PE in trauma patients remains unclear. Further studies are required to determine the true role of prophylactic IVC filters in trauma patient.

Systematic review of the use of retrievable inferior vena cava filters

PURPOSE

To review the available literature on retrievable inferior vena cava (IVC) filters to examine the effectiveness and risks of these devices.

MATERIALS AND METHODS

Investigators searched MEDLINE for clinical trials evaluating retrievable filters and reviewed the complications reported to the Manufacturer and User Facility Device Experience (MAUDE) database of the U.S. Food and Drug Administration (FDA).

RESULTS

Eligibility criteria were met by 37 studies comprising 6,834 patients. All of the trials had limitations, and no studies were randomized. There were 11 prospective clinical trials; the rest were retrospective studies. Despite the limitations of the evidence, the IVC filters seemed to be effective in preventing pulmonary embolism (PE); the rate of PE after IVC placement was 1.7%. The mean retrieval rate was 34%. Most of the filters became permanent devices. Multiple complications associated with the use of IVC filters were described in the reviewed literature or were reported to the MAUDE database; most of these were associated with long-term use (> 30 days). At the present time, the objective comparison data of different filter designs do not support superiority of any particular design.

CONCLUSIONS

In high-risk patients for whom anticoagulation is not feasible, retrievable IVC filters seem to be effective in preventing PE. Long-term complications are a serious concern with the use of these filters. The evidence of the effectiveness and the risks was limited by the small number of prospective studies.

Removal of retrievable vena cava filters in routine practice: a multicenter study

Vena cava filters (VCFs) are used to prevent pulmonary embolism when anticoagulation is contraindicated or in the event of progression of thrombosis despite adequate anticoagulation. Retrievable VCFs provide a potential advantage over permanent VCFs, but the appropriateness of their use and the frequency with which they are removed is not well established.

OBJECTIVES

Document the indications for insertion of retrievable VCFs, filter removal in hospital practice.

METHODS

Observational study conducted in three academic medical centers. Consecutive patients undergoing retrievable VCF insertion were identified. Clinical data was extracted from the patients' charts and follow up data were obtained from treating physicians after discharge.

RESULTS

300 patients were studied. The indication for filter insertion was acute bleeding (46.1%) or surgery (24.2%) in patients with acute thrombosis, prevention of venous thromboembolism in trauma (13.3%), potential bleeding in patients with deep vein thrombosis (9.1%) thromboembolism while on adequate anticoagulation (5.7%) and other (1.3%). 21 (7%) filters were removed. An unsuccessful attempt at retrieval was undertaken in a further 9 (3%) patients.

CONCLUSIONS

The use of retrievable VCFs was appropriate, with the possible exception of their prophylactic use in major trauma. The majority of VCFs were not removed, for reasons that are not apparent.

Interventional treatment of venous thromboembolism: a review

Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), is the third most common cardiovascular disease after coronary artery disease and cerebrovascular disease and is responsible for significant morbidity and mortality in the general population. Full dose anticoagulation is the standard therapy for VTE, both for the acute and the long-term phase. The latest guidelines of the American College of Chest Physicians recommend treatment with a full-dose of unfractioned heparin (UFH), low-molecular-weight-heparin (LMWH), fondaparinux, vitamin K antagonist (VKA) or thrombolysis for most patients with objectively confirmed VTE. Catheter-guided thrombolysis and trombosuction are interventional approaches that should be used only in selected populations; interruption of the inferior vena cava (IVC) with a filter can be performed to prevent life-threatening PE in patients with VTE and contraindications to anticoagulant treatment, bleeding complications during antithrombotic treatment, or VTE recurrences despite optimal anticoagulation. In this review we summarize the currently available literature regarding interventional approaches for VTE treatment (vena cava filters, catheter-guided thrombolysis, thrombosuction) and we discuss current evidences on their efficacy and safety. Moreover, the appropriate indications for their use in daily clinical practice are reviewed.

Inferior vena cava filters in children: our experience and suggested guidelines

Although use of inferior vena cava (IVC) filters for prophylaxis against pulmonary embolism (PE) is well reported in adults, long-term studies in children are lacking. We performed retrospective review of imaging and clinical database of IVC filters for the last 12 years. Thirty-five patients (mean age: 15.5 y) underwent filter placement and/or retrieval. Indications for placement were contraindication to anticoagulation with known deep venous thrombosis (DVT) (18) or high risk of venous thromboembolism (5), recurrent DVT despite anticoagulation (1), and prophylaxis before endovascular thrombolysis (8). All filter placements were technically successful without any complications. Filter retrieval was successful in 15 of 19 attempted (79%) at a mean of 42 days. Two complications occurred during retrieval: IVC stenosis successfully treated with angioplasty and contained IVC perforation. Endothelialization of filter prevented retrieval in 4 patients. Mean follow-up was 29.3 months. No patients had IVC thrombosis, breakthrough pulmonary embolism, filter fracture, or embolism. Two patients had recurrent DVT. Our results indicate that IVC filters can be successfully placed and retrieved in children with minimal procedural complications; follow-up demonstrates acceptable complication rate owing to presence of filters. Prophylactic IVC filter placement may be considered before endovascular thrombolysis for lower extremity DVT. Retrievable filters should be used in children for appropriate indications.

Diagnosis and management of life-threatening pulmonary embolism

Pulmonary embolus (PE) is estimated to cause 200 000 to 300 000 deaths annually. Many deaths occur in hemodynamically unstable patients and the estimated mortality for inpatients with hemodynamic instability is between 15% and 25%. The diagnosis of PE in the critically ill is often challenging because the presentation is nonspecific. Computed tomographic pulmonary angiography appears to be the most useful study for diagnosis of PE in the critically ill. For patients with renal insufficiency and contrast allergy, the ventilation perfusion scan provides an alternative. For patients too unstable to travel, echocardiography (especially transesophageal echocardiography) is another option. A positive result on lower extremity Doppler ultrasound can also aid in the decision to treat. The choice of treatment in PE depends on the estimated risk of poor outcome. The presence of hypotension is the most significant predictor of poor outcome and defines those with massive PE. Normotensive patients with evidence of right ventricular (RV) dysfunction, as assessed by echocardiography, comprise the sub-massive category and are at intermediate risk of poor outcomes. Clinically, those with sub-massive PE are difficult to distinguish from those with low-risk PE. Cardiac troponin, brain natriuretic peptide, and computed tomographic pulmonary angiography can raise the suspicion that a patient has sub-massive PE, but the echocardiogram remains the primary means of identifying RV dysfunction. The initial therapy for patients with PE is anticoagulation. Use of vasopressors, inotropes, pulmonary artery (PA) vasodilators and mechanical ventilation can stabilize critically ill patients. The recommended definitive treatment for patients with massive PE is thrombolysis (in addition to anticoagulation). In massive PE, thrombolytics reduce the risk of recurrent PE, cause rapid improvement in hemodynamics, and probably reduce mortality compared with anticoagulation alone. For patients with a contraindication to anticoagulation and thrombolytic therapy, surgical embolectomy and catheter-based therapies are options. Thrombolytic therapy in sub-massive PE results in improved pulmonary perfusion, reduced PA pressures, and a less complicated hospital course. No survival benefit has been documented, however. If one is considering the use of thrombolytic therapy in sub-massive PE, the limited documented benefit must be weighed against the increased risk of life-threatening hemorrhage. The role of surgical embolectomy and catheter-based therapies in this population is unclear. Evidence suggests that sub-massive PE is a heterogeneous group with respect to risk. It is possible that those at highest risk may benefit from thrombolysis, but existing studies do not identify subgroups within the sub-massive category. The role of inferior vena cava (IVC) filters, catheter-based interventions, and surgical embolectomy in life-threatening PE has yet to be completely defined.

Retrievable inferior vena cava filters are not getting retrieved: where is the gap?

OBJECTIVE

The purpose of this study is to assess the retrieval rate and the predictors of successful retrieval of Retrievable Inferior Vena Cava (RIVC) filters.

METHODS

We retrospectively reviewed the medical records of adult patients who had RIVC filter placements from 2004-2008. We excluded patients who died or were lost to follow-up and those who refused or had unsuccessful retrieval. We collected demographic and clinical data including indications for placement and follow-up. Successful retrieval was defined as objective evidence of retrieval by medical records.

RESULTS

Over a 4 year period, we identified 351 patients who had RIVC filter placements. We excluded 99 patients (65 died, 24 decided to leave filter in place, 7 had unsuccessful retrieval and 3 lost follow-up). Majority of the filters were placed for surgical patients (161, 63.9%). Of 252 eligible patients for retrieval, only 47 filters were successfully retrieved yielding a retrieval rate of 18.7%. We identified three predictors for successful retrieval: Male gender, home discharge and follow up with procedural service.

CONCLUSION

In this large cohort we found that the retrieval rate of retrievable IVCF is extremely low consistent with national statistics. Male patients, patients who were discharged home and patients who were followed by the procedural service had higher chance of successful retrieval. We recommend that procedural service placing the filter should ascertain adequate follow-up. We are not certain why more males had successful retrieval than females. Further studies are necessary to investigate this finding.

A systematic method for follow-up improves removal rates for retrievable inferior vena cava filters in a trauma patient population

BACKGROUND

Retrievable inferior vena cava filters (rIVCF) reduce the short-term risk of pulmonary embolism without the filter and inferior vena cava (IVC) thrombosis that have been reported with the use of permanent filters. Studies have shown that most rIVCFs are not removed, leaving patients at risk for thrombotic complications of rIVCF retention. We hypothesize that the application of a systematic follow-up for rIVCF will improve filter removal rates, providing patients short-term prophylaxis from pulmonary embolism whereas avoiding complications of permanent filter retention.

METHODS

The trauma registry of a Level I trauma center was queried to identify patients who underwent placement of IVCFs between January 1, 2003, and June 30, 2008. The medical records were reviewed and details of the patient's injuries, indications for filter placement, repositioning, and retrieval were collected. Radiographic images were reviewed to confirm ultimate filter retention or removal.

RESULTS

Between January 1, 2003, and June 30, 2008, rIVCFs were placed in 118 patients, 44% had known venous thromboembolic event. Three patients died before rIVCFs could be considered for extraction, leaving 115 patients for evaluation. Filters were removed in 80 patients (70%) overall. Of the 35 patients in whom filters were not removed, 11 were lost to follow-up, 4 failed removal attempts, and 20 had indications for filter retention. The rIVCFs were retrieved in 75% of patients not lost to follow-up and 92% of patients who did not have contraindications for filter removal.

CONCLUSION

A dedicated system for following-up patients with rIVCFs markedly improves removal rates of retrievable filters.