Retrievable Inferior Vena Cava Filters: Initial Clinical Results

Inferior Vena Cava Filters and Complications: A Systematic Review

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

Effects of reverse deployment of cone-shaped vena cava filter on improvements in hemodynamic performance in vena cava

BACKGROUND

Cone-shaped vena cava filters (VCFs) are widely used to treat venous thromboembolism. However, in the long term, the problem of occlusion persists even after the filter is deployed. A previous study hypothesized that the reverse deployment of a cone-shaped VCFs may prevent filter blockage.

METHODS

To explore this hypothesis, a comparative study of the traditional and reverse deployments of VCFs was conducted using a computational fluid dynamics approach. The distribution of wall shear stress (WSS) and shear stress-related parameters were calculated to evaluate the differences in hemodynamic effects between both conditions. In the animal experiment, we reversely deployed a filter in the vena cava of a goat and analyzed the blood clot distribution in the filter.

RESULTS

The numerical simulation showed that the reverse deployment of a VCF resulted in a slightly higher shear rate on the thrombus, and no reductions in the oscillating shear index (OSI) and relative residence time (RRT) on the vessel wall. Comparing the traditional method with the reversely deployed cases, the shear rate values is 16.49 and 16.48 1/s, respectively; the minimal OSI values are 0.01 and 0.04, respectively; in the vicinity of the VCF, the RRT values are both approximately 5 1/Pa; and the WSS is approximately 0.3 Pa for both cases. Therefore, the reverse deployment of cone-shaped filters is not advantageous when compared with the traditional method in terms of local hemodynamics. However, it is effective in capturing thrombi in the short term, as demonstrated via animal experiments. The reversely deployed cone-shaped filter captured the thrombi at its center in the experiments.

CONCLUSIONS

Thus, the reverse deployment of cone-shaped filters is not advantageous when compared with the traditional method in terms of local hemodynamics. Therefore, we would not suggest the reverse deployment of the cone-shaped filter in the vena cava to prevent a potentially fatal pulmonary embolism.

Study of helical flow inducers with different thread pitches and diameters in vena cava

Pulmonary embolism is a severe, potentially life-threatening condition. Inferior vena cava filters have been used to prevent recurrent pulmonary embolisms. However, the build-up of thrombosis in vena cava filters after deployment presents a severe problem to patients. Previous studies proposed that filters with helical flow are beneficial and capable of alleviating this problem. In this study, the hemodynamic performances of four typical helical flow inducers in the vena cava are determined using computational fluid dynamics simulations (steady-state and pulsatile flow) and compared. Pilot in vitro experiments were also conducted. The simulation results demonstrate that large-diameter inducers produce helical flow. Among inducers with identical diameter, those with a smaller thread pitch are more likely to induce increased helical flow. We also observed that the small thread pitch inducers can yield higher shear rates. Furthermore, a large diameter, small thread pitch helical flow inducer increases the time-averaged wall shear stress and reduces the oscillating shear index and relative residence time on the vessel wall in the vicinity of the helical flow inducer. In vitro experiments also verify that large diameter inducers generate a helical flow. A notable observation of this study is that the diameter is the key parameter that affects the induction of a helical flow. This study will likely provide important guidance for the design of interventional treatments and the deployment of filters associated with helical flow in the vena cava.

Improvement of hemodynamic performance using novel helical flow vena cava filter design

We propose a vena cava filter in which helical flow is created in the filter’s working zone to minimize filter blockage by trapped clots and facilitate the lysis of trapped clots. To validate this new design, we compared five helical flow inducers with different thread pitches in terms of blood flow patterns in the filter. The vena cava was reconstructed based on computed tomography images. Both the numerical simulation and in vitro experiment revealed that the helical flow inducer can effectively create a helical flow in the vessel, thereby subduing the filter structure’s adverse disruption to blood flow, and increasing flow-induced shear stress in the filter center. In addition, the smaller thread pitch helical flow inducer reduced the oscillating shear index and relative residence time on the vessel wall. Moreover, we observed that the helical flow inducer in the vena cava could induce flow rotation both in clockwise and counterclockwise directions. In conclusion, the new design of the filter with the smaller thread pitch inducer is advantageous over the traditional filter in terms of improving local hemodynamics, which may reduce thrombosis build-up after deployment.

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.

Current Status of the Retrieval Rate of Retrievable Vena Cava Filters in a Tertiary Referral Center in Korea

PURPOSE

The purpose of this study was to review the daily practice of inferior vena cava filters (IVCFs) in a tertiary referral center in Korea and to reveal the retrieval rate and the methods for improving it.

MATERIALS AND METHODS

Through the electronic medical record system, a retrospective review was performed on 115 consecutive patients who underwent placement of retrievable IVCFs between February 2000 and January 2011 in Seoul National University Hospital.

RESULTS

IVCF placement was done in 115 cases (113 patients). There were 68 men (59.1%), and the mean age was 58.5±15.5 years (range, 10-96 years). The affiliated departments were Vascular Surgery (57 cases, 49.6%), and Internal Medicine (20 cases, 17.4%). Advanced malignancy was the most commonly associated disease (n=30, 26%). The indications for IVCF placement were categorized; absolute indications in 36 cases (31.3%), relative indications in 78 cases (67.8%), and prophylactic use in 1 case (0.9%). The most common indications were thrombolysis/thrombectomy for iliocaval deep vein thrombosis (DVT) (n=55, 47.8). Of the 115 filters, 68 were retrieved (retrieval rate, 59%). The most common cause of non-retrieval was chronic high risk of venous thromboembolism in 24 patients (51%), followed by residual proximal DVT (n=7, 15%), and negligence by unknown reasons (n=6, 13%).

CONCLUSION

To improve the retrieval rate, the number of follow-up losses to vascular specialists must be decreased, which can be achieved by establishment of a dedicated IVC filter clinic, implementation of a filter registry, and regular education for medical teams and patients along with their families.

Troubleshooting OptEase inferior vena cava filter retrieval

For treatment of deep vein thrombosis and prevention of pulmonary thromboembolism, a retrievable inferior vena cava filter is commonly utilized as an effective bridge to anticoagulation. However, we have experienced difficulties in retrieving inferior vena cava filters. Endovascular retrieval assisted by disposable biopsy forceps is an appropriate approach because it provides a less-invasive low-cost way to remove a migrated filter. We suggest this troubleshooting technique to deal with filter hook migration into the caval wall.

Tempofilter II implantation in patients with lower extremity fractures and proximal deep vein thrombosis

PURPOSE

We aimed to examine the efficacy and safety of Tempofilter II (B. Braun, Melsungen, Germany) implantation to prevent pulmonary embolism in patients with lower-extremity fractures and proximal deep vein thrombosis (DVT).

MATERIALS AND METHODS

The records of patients with lower limb fractures and proximal DVT who were implanted with Tempofilter II devices from May 2004 to August 2009 were reviewed. Data collected included success rate, occurrence of pulmonary embolism, retrieval rate, and complications.

RESULTS

A total of 176 eligible patients, including 129 males (73.3%) and 47 females (26.7%) with a median age of 42.0 years (interquartile range [IQR], 34.0-52.0 years) were included in the study. Filters were successfully implanted in 174 patients (98.9%). One patient experienced a pulmonary embolism after implantation and died. Filters were removed without complications in all other patients. Median filter implantation time was 27 days (IQR, 25.0-29.0 days). Visible organized thrombi were present on the surface of 144 (82.8%) of filters after removal, and the diameter of most thrombi (n=124) ranged from 0.5 to 1.0 cm. Filters migrated <2 cm in 104 patients (59.8%) and ≥ 2 cm in five patients (2.9%). In these five cases, three filters migrated into the right atrium and two migrated to the orifice of the renal veins.

CONCLUSION

Tempofilter II is safe and may be useful in cases of lower extremity fracture with proximal DVT for the prevention of pulmonary embolism. The filter is easily placed and retrieved, and associated with minimal complications.

Successful cases of difficult inferior vena cava filter retrieval with the use of biopsy forceps: Biopsy forceps technique

Objectives:

For treatment and prevention of deep vein thrombosis(DVT) and pulmonary embolism(PE), retrievable inferior vena cava(IVC) filters have commonly been used as an effective bridge to anticoagulation. However, we experienced unexpected difficulty in endovascular retrieval of some IVC filters. Most problems were due to endovascular treatment devices issues, filter intimal migration, filter disintegration, filter-associated thrombosis, and right atrium/ventricle migration.

Methods:

Disposable biopsy forceps was used to engage the filter hook and reform the shape of the filter struts. Endovascular retrieval assisted by use of the biopsy forceps via a similar vein was effective and provided a less-invasive, low cost method for removal of problematic IVC filters.

Results:

We described easily performed methods that uses disposable biopsy forceps for the retrieval of IVC filters that are difficult to remove because of filter hook migration into the caval wall.

Conclusion:

We developed an easily performed method that uses intestine biopsy forceps for the retrieval of IVC filter that are difficult to remove.

Thromboprophylaxis in patients with pelvic and acetabular fractures: A short review and recommendations

The management of thromboprophylaxis in patients with pelvic and acetabular fractures remains a highly controversial topic within the trauma community. Despite anticoagulation, venous thromboembolism (VTE) remains the most common cause of surgical morbidity and mortality in this high-risk patient group. Although various thromboprophylactic regimes are employed, evidence relating to the most effective method remains unclear. Controversies surrounding screening, the use of prophylactic inferior vena cava filters (IVCF) and chemothromboprophylaxis in polytraumatised patients, particularly those with pelvic and acetabular fractures, form the basis of considerable debate. With the absence of a well-designed clinical trial and the presence of ongoing controversies within the literature, this review will explore current treatment options available to trauma surgeons and highlight differing scientific opinions, providing an update on the role of screening and current available preventative measures. We cover existing as well as recent advances in chemical thromboprophylactic agents and discuss external mechanical compression devices, the usefulness of serial duplex ultrasonography and the role of extended chemothromboprophylaxis on discharge. The evidence behind prophylactic IVCF is also considered, along with reported complication profiles. We conclude with a proposed protocol for use in major trauma centres, which can form the basis of local policy for the prevention of VTE in trauma patients with pelvic and acetabular fractures.

Inferior vena cava filtration in the management of venous thromboembolism: filtering the data

Venous thromboembolism (VTE) is a common cause of morbidity and mortality. This is especially true for hospitalized patients. Pulmonary embolism (PE) is the leading preventable cause of in-hospital mortality. The preferred method of both treatment and prophylaxis for VTE is anticoagulation. However, in a subset of patients, anticoagulation therapy is contraindicated or ineffective, and these patients often receive an inferior vena cava (IVC) filter. The sole purpose of an IVC filter is prevention of clinically significant PE. IVC filter usage has increased every year, most recently due to the availability of retrievable devices and a relaxation of thresholds for placement. Much of this recent growth has occurred in the trauma patient population given the high potential for VTE and frequent contraindication to anticoagulation. Retrievable filters, which strive to offer the benefits of permanent filters without time-sensitive complications, come with a new set of challenges including methods for filter follow-up and retrieval.

Successful catheter directed thrombolysis in postpartum deep venous thrombosis complicated by nicoumalone-induced skin necrosis and failure in retrieval of inferior vena caval filter

Venous thromboembolism is an important cause for maternal morbidity and mortality in postpartum period. Though catheter-directed thrombolysis (CDT) is now considered as a safe and effective therapy for the management of deep venous thrombosis (DVT) but still it is not indicated in postpartum DVT. We are presenting a case of 22-year-old female patient who presented with post-partum lower limb DVT and managed successfully with CDT by using injection streptokinase and temporary inferior vena caval filter was inserted as prophylactic for pulmonary embolism as she had extensive DVT extending into inferior vena cava (IVC). During follow-up, she developed large skin necrosis in left lower limb which was managed by adding injection low-molecular-weight heparin. IVC filter also could not be retrieved even after trying all manoeuvres during follow-up after 2 weeks.

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.

Inferior vena cava filters for primary prophylaxis: when are they indicated?

Over the past several years there has been a rapid increase in the number of inferior vena cava (IVC) filters placed for primary thromboprophylaxis. Increased use has occurred in settings where other methods of thromboprophylaxis are viewed to be inadequate, technically challenging, or that place patients at an unacceptably high bleeding risk. These clinical services include trauma, bariatric surgery, neurosurgery, cancer, intensive care unit populations, and patients with a relative contraindication to anticoagulation. We review the studies to date addressing filter placement for these indications. Although preliminary data are promising, the patient populations most likely to benefit from prophylactic IVC filter placement have not been well defined, and randomized studies demonstrating efficacy have not been conducted. Moving forward, it will be critical to accomplish these two tasks if IVC filters are to continue to have a role in primary thromboprophylaxis.

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.

Vena cava filter practices of a regional vascular surgery society

BACKGROUND

Vena cava filter (VCF) use in the United States has increased dramatically with prophylactic indications for placement and the availability of low-profile retrievable devices, which are overtaking the filter market. We surveyed the practice patterns of a large group of vascular surgeons from a regional vascular surgery society to see whether they mirrored current national trends.

METHODS

A 17-question online VCF survey was offered to all members of the Southern Association of Vascular Surgery. The responses were analyzed using the χ(2) goodness of fit tests.

RESULTS

Of the 276 members surveyed, 126 (46%) responded, with 118 (93%) indicating that they placed filters during their practice. Highly significant differences were identified with each question (at least P < 0.002). Regarding the inferior vena cava, the preferred permanent filters were the Greenfield (31%), the TrapEase (15%), the Vena Tech (5%), and a variety of retrievable devices (49%). Fifty percent of the respondents placed retrievable filters selectively; 26% always placed them; and 24% never did. Filters were placed for prophylactic indications <50% of the time by 63% of the respondents. Overall, retrievable filters (when not used as permanent filters) were removed <25% of the time by 64% of the respondents and <50% of the time by 78% of the respondents. The femoral vein was the preferred access site for 84% of the respondents. Major complications were few but included filter migration to the atrium (one), atrial perforation (one), abdominal pain requiring surgical filter removal (two), inferior vena cava thrombosis (12 vena cava thrombosis--4 due to TrapEase filters), strut fracture with embolization to heart or lungs (three Bard retrievable filters), and severe tilting precluding percutaneous retrieval and protection from pulmonary emboli (8 filters with severe tilt--7 of which were Bard). Of the respondents, 59% had never placed a superior vena cava filter, and 28% had placed five or fewer.

CONCLUSIONS

Although VCF insertion overall appears safe, some complications are specific to biconical and certain retrievable filters. Given the low removal rate and lack of long-term experience with retrievable filters, routine use of these devices as permanent filters should be questioned. If used on a temporary basis, there should be a plan for filter removal at the time of implantation.

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.

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.

Optional inferior vena cava filters in the trauma patient

Trauma patients are at exceedingly high risk of development of venous thromboembolism (VTE) including deep venous thrombosis and pulmonary embolism (PE). The epidemiology of VTE in trauma patients is reviewed. PE is thought to be the third major cause of death after trauma in those patients who survive longer than 24 hours after onset of injury. In fact, patients recovering from trauma have the highest rate of VTE among all subgroups of hospitalized patients. Various prophylactic and surveillance methods have been evaluated and found helpful in certain situations, but VTE complications can occur despite such measures. Therapeutic and prophylactic uses of inferior vena cava (IVC) filters in trauma patients are reviewed. Prophylactic IVC filter use is revealed to be a controversial subject with valid arguments on both sides of the issue. With the lack of prospective randomized trials of IVC filter use in trauma, it is impossible to make evidence-based recommendations. Unfortunately, two sets of guidelines are available for insertion of filters in trauma patients, with conflicting recommendations. The introduction of retrievable IVC filters seems to offer a unique solution for VTE protection in the trauma patient population, which often consists of younger members of our population. Lastly, current generations of FDA-approved retrieval filters are discussed.

Retrieval of a wall-embedded recovery inferior vena cava filter using rigid bronchoscopy forceps

Optional inferior vena cava (IVC) filters are an attractive option to help prevent pulmonary embolism because these filters can be retrieved when the risk for thromboembolic events has passed. Retrieval of IVC filters can be difficult if the filter tilts and its tip becomes embedded into the wall of the IVC. A case is presented in which rigid bronchoscopy forceps were used to retrieve a filter that had become embedded in the wall of the IVC.

A Policy of Dedicated Follow-Up Improves the Rate of Removal of Retrievable Inferior Vena Cava Filters in Trauma Patients

Retrievable Inferior Vena Cava Filters (IVCF) for prophylaxis against pulmonary embolus have been associated with low rates of removal. Strategies for improving the rates of retrieval have not been described. We hypothesized that a policy of dedicated follow-up would achieve a higher rate of filter removal. Trauma and Nontrauma patients who had a retrievable IVCF placed during 2006 were identified. A protocol existed for trauma patients with chart stickers, arm bracelets, and dedicated follow-up by nurse practitioners from three trauma teams. No protocol existed for nontrauma patients. Statistical analysis was performed using χ2 analysis or analysis of variance. One hundred sixty-seven retrievable IVCFs were placed over 12 months; 91 in trauma patients and 76 in nontrauma patients. Trauma patients were more likely to have their IVCF removed than nontrauma patients, 55 per cent versus 19 per cent, P < 0.001. There were differences between the three trauma teams, with removal rates of 44 per cent, 42 per cent, and 86 per cent respectively ( P < 0.05). On multivariate analysis young age and trauma patient status were independent predictors of filter removal. A policy of dedicated follow-up of patients with IVCFs can achieve significantly higher rates of filter removal than have been previously reported. Similar policies should be adopted by all centers placing retrievable IVCFs to maximize retrieval rates.

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.

Case of a misplaced IVC filter: a lesson to learn

The inferior vena cava (IVC) filter insertion is a well established procedure to prevent significant pulmonary embolism in selected situations. It is generally considered straight forward without significant complications. We report an interesting case of a young postpartum woman in whom an IVC filter was misplaced in the right gonadal vein. This complication is only rarely reported. Presence of prominent right gonadal vein must always be kept in mind during trans-jugular placement of infra renal filter in the IVC in post partum women.

Retrievable vena cava filters: a clinical review

Vena cava filters were developed as a method of preventing pulmonary embolism (PE) in patients with venous thromboembolism (VTE) at risk for bleeding from therapeutic anticoagulation. However, the long-term complications of filter placement, such as caval thrombosis, have mitigated some of the benefits, particularly in those patients with only a temporary contraindication to anticoagulation. Retrievable filters were designed to avoid the long-term risks of a permanent filter while still providing short-term protection against PE. As a result, their use has expanded from patients with known thrombosis to those without VTE who are at high risk for developing PE. In this review, we discuss the different types of retrievable filters, indications for their placement, complications that can occur during and after placement, and their use as prophylaxis in surgical patients. Although the use of retrievable filters in patients with known VTE is clear, further studies are needed to establish their prophylactic efficacy in the surgical patient. Until this evidence is available, we recommend that retrievable filters should be used only in patients with acute VTE who are at risk for recurrent thromboembolism and have a transient risk for bleeding.

Intravascular Ultrasound—Guided Inferior Vena Cava Filter Placement in the Military Multitrauma Patients: A Single-Center Experience

Background: High velocity fragments have resulted in a multitude of complex injuries in the military patients, placing them at increased risk of venous thromboembolism. Methods: A retrospective analysis was performed of all the intravascular ultrasound (IVUS)-guided bedside inferior vena cava (IVC) filters placed between August 2003 and October 2007. Results: Fourteen patients had bedside IVUS-guided retrievable filter placement. Thirteen males and one female and the mean (+SD) injury severity scores (ISS) was 37.2 (+9.9). The most common causes of injury were explosive devices (57%), gunshot wounds (28%), rocket-propelled grenades (7%), and motor vehicle crashes (7%). Indications for filter insertion were deep venous thrombosis in 36% of patients and pulmonary embolus in 28%. Thirty five percent had filters inserted prophylactically. Conclusions: Military trauma population ISS is considerably higher than what is reported in the civilian population. The bedside IVUS-guided IVC filter insertion is particularly useful in this population.

Endovascular treatment for iliac vein compression syndrome: a comparison between the presence and absence of secondary thrombosis

Objective

To evaluate the value of early identification and endovascular treatment of iliac vein compression syndrome (IVCS), with or without deep vein thrombosis (DVT).

Materials and Methods

Three groups of patients, IVCS without DVT (group 1, n = 39), IVCS with fresh thrombosis (group 2, n = 52) and IVCS with non-fresh thrombosis (group 3, n = 34) were detected by Doppler ultrasonography, magnetic resonance venography, computed tomography or venography. The fresh venous thrombosis were treated by aspiration and thrombectomy, whereas the iliac vein compression per se were treated with a self-expandable stent. In cases with fresh thrombus, the inferior vena cava filter was inserted before the thrombosis suction, mechanical thrombus ablation, percutaneous transluminal angioplasty, stenting or transcatheter thrombolysis.

Results

Stenting was performed in 111 patients (38 of 39 group 1 patients and 73 of 86 group 2 or 3 patients). The stenting was tried in one of group 1 and in three of group 2 or 3 patients only to fail. The initial patency rates were 95% (group 1), 89% (group 2) and 65% (group 3), respectively and were significantly different (p = 0.001). Further, the six month patency rates were 93% (group 1), 83% (group 2) and 50% (group 3), respectively, and were similarly significantly different (p = 0.001). Both the initial and six month patency rates in the IVCS patients (without thrombosis or with fresh thrombosis), were significantly greater than the patency rates of IVCS patients with non-fresh thrombosis.

Conclusion

From the cases examined, the study suggests that endovascular treatment of IVCS, with or without thrombosis, is effective.

Bedside placement of removable vena cava filters guided by intravascular ultrasound in the critically injured

BACKGROUND

Bedside placement of removable inferior vena cava filters (RVCF) is increasingly used in critically injured patients. The need for fluoroscopic equipment and specialized intensive care unit beds presents major challenges. Intravascular ultrasound (IVUS) eliminates such problems. The objective of the present study was to analyze the safety and feasibility of IVUS-guided bedside RVCF placement in critically injured patients.

METHODS

Between October 2004 and July 2006 47 IVUS-guided RVCF were placed at the bedside. Medical and trauma registry records were reviewed. Primary outcome was RVCF-related complications.

RESULTS

The mean patient age was 41 +/- 19 years, and the mean Injury Severity Score was 30 +/- 12. The right common femoral vein was chosen as the site of access in 40 patients, and the left common femoral vein was the access site in 7 patients. The insertion was performed 3.7 +/- 2.5 days after admission. Four patients (8.5%) developed common femoral deep vein thrombosis (DVT) and three (6%) developed a peripheral pulmonary embolism (PE). Complications related to technique were recorded in two patients (4%) and included one misplacement and one access site bleeding with no further associated morbidity. Five patients died during the hospital stay from issues unrelated to RVCF. Forty-one patients were eligible for follow-up. Removal of RVCF was offered only to 8 patients and was performed successfully in 4 (10%) at a mean of 130 days (range: 44-183 days).

CONCLUSIONS

In this study IVUS-guided bedside placement of RVCF was feasible but was also associated with complications. Follow-up was poor, and the rate of removal disappointingly low, underscoring the need for further exploration of the role of RVCF.

Form And Function Of Vena Cava Filters: How Do Optional Filters Measure Up?

The function of vena cava filters, preventing pulmonary embolism while maintaining caval patency, is associated with the design. Several characteristics have been reported. This report evaluates retrievable filter designs in comparison with previously marketed designs with respect to efficacy and safety. Three inferior vena cava (IVC) filters (Gunther Tulip, Bard Recovery, and the Cordis OptEase) were compared on the basis of design characteristics associated with function, shape, number of trapping levels, and fixation. Adverse events reported in the literature and to the US Food and Drug Administration Manufacturers and User Facility Device Experience Database (MAUDE) were summarized. The major differences among device types include the fixation, the volume and number of trapping levels, and the amount of metal in the IVC. The MAUDE registry reported adverse events that had been hypothesized from the analysis of in vitro and in vivo testing. The Recovery and OptEase filters had the highest number of clinically important reports. From 12 to 57% were retrieved between 3 days and 11 months. Adaptations made to facilitate retrieval led to unacceptable sequelae. The small number removed, the length of time they are left in place, and the risks associated with retrieval suggest that optional filters may not be equivalent to approved permanent devices.

Retrievable vena cava filters: Key considerations

Retrievable filters are a new generation of inferior vena cava (IVC) filters and represent 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 the currently available literature regarding retrievable IVC filters is summarized and their efficacy and safety is discussed. Moreover, the appropriate indications for their use are reviewed. Retrievable filters are becoming safer and easier to use; in fact the bioengineering research has optimized the technical characteristics of these devices, in order to reduce the incidence of possible complications. However, there are important unresolved issues, including the appropriate maximum implantation time, the possibility to safely and efficaciously remove the filters without being compromised by entrapped clots, and the use of anticoagulation during the implantation and periremoval periods. Large prospective cohort studies or randomized trials are strongly warranted to definitely clarify the beneficial role of these devices.

Ins and outs of inferior vena cava filters in patients with venous thromboembolism: the experience at Monash Medical Centre and review of the published reports

BACKGROUND

Inferior vena cava (IVC) filters are an alternative management strategy to anticoagulation in patients with venous thromboembolism (VTE). However, an IVC filter has its own inherent risks and complications and may not be the best management strategy. The aims of this study were to evaluate our institution's practice of permanent Vena Tech (B. Braun Medical S.A., Boulogne, France) and retrievable Gunther Tulip (William Cook Europe, Bjaeverskov) IVC filters and to review the available published reports.

METHODS

Retrospective single centre audit from the medical record.

RESULTS

Eighty-three and 42 patients had a VT and GT filter inserted, respectively. Median age was 57 years for VT and 63 years for GT. The majority (75% for VT and 83% for GT) was inserted for acute VTE and contraindication to anticoagulation. Both filters were efficacious at preventing pulmonary embolism (PE) and there was a low rate of recurrent deep venous thrombosis in both groups. Insertion-related complications were low in both groups. Of the GT filters (n = 42), 16 were deemed an ongoing requirement, and thus, removal was not planned. In a further six patients, there was insufficient documentation as to why removal was not planned. Removal was attempted in 19 patients and was successful in 11. Failure of removal was as a result of clot in the filter (n = 7) or inability to snare it (n = 1).

CONCLUSIONS

Both the permanent and retrievable filters are efficacious at preventing PE and are associated with a low complication rate. Planned removal of the GT filter may not be possible in a significant proportion of cases.

Changing Patterns in the Use of Inferior Vena Cava Filters: Review of a Single Center Experience

BACKGROUND

The aim of this study was to review a Level I trauma center's pattern of use of IVC filters over a 6-year period.

STUDY DESIGN

During the years 1999 to 2004, 878 patients underwent placement of an IVC filter at our institution. We reviewed patient charts and collected data pertaining to patient demographics, types of filters, indication for placement, modes of venous access, and complication rates.

RESULTS

Our institution demonstrated an increase in prophylactic filter placement and the use of retrievable IVC filters. There was also an increasing trend in obtaining venous access through the jugular vein during filter placement.

CONCLUSIONS

IVC filters have proved safe and effective in preventing pulmonary embolism when used in a properly selected group of patients. With the introduction of new technology, such as retrievable IVC filters, ongoing efforts must be undertaken to define the indications for placement, duration of therapy, and the suitability of patients for the procedure.

Long-Term Retrievability of IVC Filters: Should We Abandon Permanent Devices?

Thromboembolic disease produces a considerable disease burden, with death from pulmonary embolism in the UK alone estimated at 30,000-40,000 per year. Whilst it is unproven whether filters actually improve longevity, the morbidity and mortality associated with thromboembolic disease in the presence of contraindications to anticoagulation is high. Thus complications associated with filter insertion, and whilst they remain in situ, must be balanced against the alternatives. Permanent filters remain in situ for the remainder of the patient's life and any complications from the filters are of significant concern. Filters that are not permanent are therefore attractive in these circumstances. Retrievable filters, to avoid or decrease long-term filter complications, appear to be a significant advance in the prevention of pulmonary embolism. In this review, we discuss the safety and effectiveness of both permanent and retrievable filters as well as the retrievability of retrievable inferior vena cava (IVC) filters, to explore whether the use of permanent IVC filters can be abandoned in favor of retrievable filters. Currently four types of retrievable filters are available: the Recovery filter (Bard Peripheral Vascular, Tempe, AZ, USA), the Günther Tulip filter (Cook, Bloomington, IN, USA), the OptEase Filter (Cordis, Roden, The Netherlands), and the ALN filter (ALN Implants Chirurgicaux, Ghisonaccia, France). Efficacy and safety data for retrievable filters are as yet based on small series, with a total number of fewer than 1,000 insertions, and follow-up is mostly short term. Current long-term data are poor and insufficient to warrant the long-term implantation of these devices into humans. The case of fractured wire from a Recovery filter that migrated to the heart causing pericardial tamponade requiring open heart surgery is a reminder that any new endovascular device remaining in situ in the long term may produce unexpected problems. We should also bear in mind that the data on permanent filters are much more robust, with reports on over 9,500 cases with follow-up of up to 8 years. The original implantation time of 10-14 days has been extended to more than 100 days as the mean implantation time with some of the filter types. Follow-up (preferably prospective) is necessary for all retrievable filters, whether or not they are retrieved. Until these data become available we should restrict ourselves to the present indications of permanent and retrievable filters. If long-term follow-up data on larger numbers of cases confirm the initial data that retrievable filters are as safe and effective as permanent filters, the use of the retrievable filters is likely to expand.

Early Placement of Optional Vena Cava Filter in High-Risk Patients with Traumatic Brain Injury

OBJECTIVES

Patients sustaining severe trauma are at high risk for the development of venous thromboembolic events (VTE). Pharmacologic VTE prophylaxis may be contraindicated early after trauma due to potential bleeding complications. The purpose of this study was to evaluate safety and feasibility of early prophylactic vena cava filter (VCF) placement and subsequent retrieval in multiple injured patients with traumatic brain injury (TBI).

METHODS

Analysis of single-institution case series of consecutive patients who received a prophylactic VCF after severe TBI (Abbreviated Injury Scale, AiS ≥ 3) between August 2003 and October 2006.

RESULTS

A total of 34 optional VCF were prophylactically placed with a median delay of 1 day after trauma (range, 0-7 days). All patients had sustained multiple injuries (median Injury Severity Score 41, range, 18-59) with severe TBI (median AiS 4, range 3-5). Median age was 41 years (range, 17-67 years). Two patients had succumbed before potential filter retrieval. Of the remaining patients, 27 (84%) had their filters uneventfully retrieved between 11 and 32 days (median, 18 days) after placement with no retrieval-related morbidity. Five VCF (16%) were left permanently. In one patient (3%) early inferior vena cava occlusion and deep venous thrombosis occurred 14 days after VCF placement. Symptomatic pulmonary embolism was observed in one patient (3%) 5 days after VCF retrieval. Overall trauma-related mortality was 9%.

CONCLUSIONS

Early VCF placement may be of benefit for multiple injured patients with TBI when pharmacologic VTE prophylaxis is contraindicated. VCF retrieval is safe and feasible. Filter placement- and retrieval-related morbidity is low.

In Vitro Evaluation of Optionally Retrievable and Permanent IVC Filters

PURPOSE

To systematically evaluate different optionally retrievable and permanent inferior vena cava (IVC)-filters with respect to their capture rates.

MATERIAL AND METHODS

Seven optionally retrievable and permanent IVC filters were tested in an in vitro flow model with a tube size of 22 mm in horizontal and vertical positions. To analyze the capture efficiency the IVC filters were implanted in concentric and eccentric positions and subsequently exposed to single and multiple blood clots of different sizes (3x5, 3x10, 5x10, 5x20, 7x20, 10x24 mm). Capture rates and pressure changes were measured and compared between the different IVC filters.

RESULTS

There were significant differences between the tested IVC filters. In general, the capture rate improved with increasing clot size (P<0.0001). In the single-clot exposure the highest mean capture rate was achieved with the Celect filter (90.4%+/-15.7%), whereas the Günther Tulip filter achieved best results in the multi-clot exposure (76.7%+/-12.5%). Capture rates differed significantly between the various IVC filters (single-clot: P<0.0001; multi-clot: P=0.0016). The position (horizontal or vertical) did not show a significant influence, whereas capture rates significantly decreased in the multi-clot test with eccentric filter positions (P=0.0299). In this study optionally retrievable IVC filters were more efficient than the tested permanent IVC filters (single-clot: P<0.0001; multi-clot: P=0.0002).

CONCLUSIONS

Optionally retrievable IVC filters are efficient. Clot size, IVC filter type, and position significantly influence capture rate. Deliberate selection of the most efficient IVC filter and concentric positioning are important to ensure optimal results.

Safety of Inferior Vena Cava Filter Retrieval in Anticoagulated Patients

PURPOSES

To evaluate the safety of inferior vena cava (IVC) filter retrieval in therapeutically anticoagulated patients in comparison to prophylactically or not therapeutically anticoagulated patients with respect to retrieval-related hemorrhagic complications.

MATERIALS AND METHODS

This was a retrospective study of 115 consecutive attempted IVC filter retrievals in 110 patients. Filter retrievals were stratified as performed in patients who were therapeutically anticoagulated (group 1), prophylactically anticoagulated (group 2), or not therapeutically anticoagulated (group 3). The collected data included anticoagulant and antiplatelet medications (type, form and duration of administration, dosage) at the time of retrieval. Phone interviews and chart review was performed for the international normalized ratio (INR), activated partial thromboplastin time, platelet count, infusion of blood products, and retrieval-related hemorrhagic complications.

RESULTS

Group 1 included 65 attempted filter retrievals in 61 therapeutically anticoagulated patients by measured INR or dosing when receiving low-molecular-weight heparin (LMWH). Four retrievals were not successful. In patients receiving oral anticoagulation, the median INR was 2.35 (range, 2 to 8). Group 2 comprised 23 successful filter retrievals in 22 patients receiving a prophylactic dose of LMWH. Group 3 included 27 attempted filter retrievals in 27 patients not receiving therapeutic anticoagulation. Six retrievals were not successful. Five patients were receiving oral anticoagulation with a subtherapeutic INR (median, 1.49; range, 1.16 to 1.69). No anticoagulation medication was administered in 22 patients. In none of the groups were hemorrhagic complications related to the retrieval procedures identified.

CONCLUSIONS

These results suggest that retrieval of vena cava filters in anticoagulated patients is safe. Interruption or reversal of anticoagulation for the retrieval of vena cava filters is not indicated.

Vena cava filters and inferior vena cava thrombosis

OBJECTIVE

Retrievable vena cava filters (R-VCF) are a recent addition to the therapeutic armamentarium for the prevention of pulmonary embolism. However, unlike permanent vena cava filters (P-VCF), outcomes data are limited regarding complication rates.

METHODS

This was a retrospective comparative analysis of consecutive patients undergoing placement of R-VCF vs P-VCF at Wake Forest University School of Medicine from January 2000 to December 2004. Data collected included demographics, procedural specifics, filter type, indications, and complications. Summary data are expressed as number (percentage) or mean +/- SD. Continuous and categorical variables were analyzed by using t and Fisher exact testing, as appropriate. Four additional patients with vena cava thrombosis were also referred to our institution for treatment during the study period, all with opposed biconical VCFs (OptEase and TrapEase filters) recently placed at other facilities. This last group of patients is described but not included in the analysis.

RESULTS

A total of 189 VCF (165 P-VCF and 24 R-VCF) cases were examined. No significant differences in VCF groups were observed according to age, documented hypercoagulability, or concomitant anticoagulation. Significant differences were observed according to sex (30.3% of P-VCF vs 62.5% of R-VCF patients were female), morbid obesity (4.2% of P-VCF vs 25% of R-VCF patients), active malignancy (20% of P-VCF vs 41.7% of R-VCF patients), and indication for VCF placement. Over a median follow-up of 8.5 months, no case of significant hemorrhage, no VCF migration, and four cases of vena cava thrombosis were observed. Vena cava thrombosis was observed more frequently in the presence of R-VCF when compared with P-VCF (12.5% vs 0.6%; P = .007). All observed vena cava thromboses were associated with severe clinical symptoms and occurred in patients who received opposed biconical VCF designs.

CONCLUSIONS

In our experience, both P-VCF and R-VCF can be placed safely. Among both permanent and retrievable devices, however, opposed biconical designs seem to be associated with an increased risk for vena cava thrombosis. Although causative factors remain unclear, filter design and resultant flow dynamics may play an important role, because all episodes of vena cava thrombosis occurred in patients with a single-filter design.

Safety and efficacy of vena cava filters in trauma patients

Pulmonary embolism (PE), due to its sudden onset, notoriously difficult diagnosis, unpredictable nature and often fatal outcome, remains one of the most feared complications in surgical practice. Trauma patients with multisystem injuries, extremity or pelvic fractures and head or spinal cord injuries often pose a significant dilemma for the surgeon because of the inability to use conventional measures such as anticoagulation therapy and compression devices. On the other hand, the incidence of deep vein thrombosis (DVT) is high among trauma patients and the attendant risk of PE is an important cause of morbidity and mortality. Inferior vena cava (IVC) interruption by placement of diverse filtering devices has evolved over the past three decades. With the use of these devices, the risk of PE has been reduced dramatically. However, variable rates of complications are reported from their use. In this study, we review all the available data on IVC filter placement in trauma patients and we discuss the potential complications of IVC filters in order to understand better the risk/benefit ratio of their use.