Multicenter Trial of the VenaTech Convertible Vena Cava Filter

The Role of IVC Filters in the Management of Acute Pulmonary Embolism

Venous thromboembolism (VTE), comprising deep venous thrombosis (DVT) and pulmonary embolism (PE), is a prevalent cardiovascular condition, ranking third globally after myocardial infarction and stroke. The risk of VTE rises with age, posing a growing concern in aging populations. Acute PE, with its high morbidity and mortality, emphasizes the need for early diagnosis and intervention. This review explores prognostic factors for acute PE, categorizing it into low-risk, intermediate-risk, and high-risk based on hemodynamic stability and right ventricular strain. Timely classification is crucial for triage and treatment decisions. In the contemporary landscape, low-risk PE patients are often treated with Direct Oral Anticoagulants (DOACS) and rapidly discharged for outpatient follow-up. Intermediate- and high-risk patients may require advanced therapies, such as systemic thrombolysis, catheter-directed thrombolysis, mechanical thrombectomy, and IVC filter placement. The latter, particularly IVC filters, has witnessed increased usage, with evolving types like retrievable and convertible filters. However, concerns arise regarding complications and the need for timely retrieval. This review delves into the role of IVC filters in acute PE management, addressing their indications, types, complications, and retrieval considerations. The ongoing debate surrounding IVC filter use, especially in patients with less conventional indications, reflects the need for further research and data. Despite complications, recent studies suggest that clinically significant issues are rare, sparking discussions on the appropriate and safe utilization of IVC filters in select PE cases. The review concludes by highlighting current trends, gaps in knowledge, and potential avenues for advancing the role of IVC filters in future acute PE management.

A review of inferior vena cava filters

The care of patients with venous thromboembolism (VTE) is delivered via a multidisciplinary team. The primary treatment for VTE is anticoagulation; however, placement of filter devices in the inferior vena cava (IVC) to prevent embolisation of deep venous thrombosis (DVT) is a well-established secondary treatment option. Many controversies remain regarding utilisation and management of filters.

Vena caval filters for the prevention of pulmonary embolism in people at high risk of, or with established venous thromboembolism

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

To assess the efficacy and safety of vena caval filters (VCFs) in preventing acute pulmonary embolism (APE) in people with established venous thromboembolism (VTE), or those at high risk of developing APE. 

Back to the Basics: Inferior Vena Cava Filters

Inferior vena cava filters are an important therapeutic option for patients with venous thromboembolism and contraindication to anticoagulation. Indications for filter placement have varied over the previous decades. This article discusses the history of inferior vena cava filter use, with a basic overview of technology and specific devices. Finally, this article reviews emerging filter design and technology. Understanding the basics of inferior vena cava filters is critical to building more robust clinical data for the purpose of improving patient outcomes.

Hazardous Situation During Conversion of a Long-term Indwelling VenaTech Convertible Inferior Vena Cava Filter

BACKGROUND

A lack of high-quality research and data has restricted the comprehensive understanding of the conversion procedure of convertible inferior vena cava filters. The aim of this study was to present an unusual situation with a high risk of causing complication, during conversion of VenaTech convertible inferior vena cava filter and our management procedure.

METHODS

Lower extremity deep venous thrombi were detected in a 62-year-old woman before major orthopedic surgery. A VenaTech convertible inferior vena cava filter was placed to prevent possible pulmonary embolism and 106 days later, the filter was converted without any complications.

RESULTS

At the 6-month follow-up, no adverse events were reported.

CONCLUSIONS

The long-term indwelling of a filter might increase the complexity and uncertainty of the conversion procedure. This report presented a rare but hazardous situation during conversion and our management procedure.

Current Controversies in Inferior Vena Cava Filter Placement: AJR Expert Panel Narrative Review

Despite inferior vena cava (IVC) filter practice spanning over 50 years, interventionalists face many controversies in proper utilization and management. This article reviews recent literature and offers opinions on filter practices. IVC filtration is most likely to benefit patients at high risk of iatrogenic pulmonary embolus during endovenous intervention. Filters should be used selectively in patients with acute trauma or who are undergoing bariatric surgery. Retrieval should be attempted for perforating filter and fractured filter fragments when imaging suggests feasibility and favorable risk-to-benefit ratio. Antibiotic prophylaxis should be considered when removing filters with confirmed gastrointestinal penetration. Anticoagulation solely because of filter presence is not recommended except in patients with active malignancy. Anticoagulation while filters remain in place may decrease long-term filter complications in these patients. Patients with a filter and symptomatic IVC occlusion should be offered filter removal and IVC reconstruction. Physicians implanting filters may maximize retrieval by maintaining physician-patient relationships and scheduling follow-up at time of placement. Annual follow-up allows continued evaluation for removal or replacement as appropriate. Advanced retrieval techniques increase retrieval rates but require caution. Certain cases may require referral to experienced centers with additional retrieval resources. The views expressed should help guide clinical practice, future innovation, and research.

Hemodynamic Analysis of VenaTech Convertible Vena Cava Filter Using Computational Fluid Dynamics

The VenaTech convertible filter (VTCF) has been widely used as an inferior vena cava (IVC) filter to prevent fatal pulmonary embolism in patients. However, its hemodynamics that greatly affect the filter efficacy and IVC patency are still unclear. This paper uses computational fluid dynamics with the Carreau model to simulate the non-Newtonian blood flows around the VTCF respectively deployed in the normal, reverse and three converted states in an IVC model. The results show that the prothrombotic stagnation zones are observed downstream from the normal, reverse and small open VTCFs, with the streamwise length is nearly eight times the IVC diameter. The no-slip boundary conditions of the thin-wire VTCF arms lead to the “viscous block” effect. The viscous block accelerates the blood flow by 5–15% inside the IVC and enhances the filter wall shear stress up to nearly 20 times that of the IVC only, which contributes to clot capture and thrombus lysis. The relative flow resistance is defined to evaluate the filter-induced resistance on the IVC blood flow that can be regarded as an index of IVC patency with the filter deployment. The flow resistance of the normal VTCF deployment increases dramatically by more than 60% compared with that of the IVC only and is a little higher (6%) than that of the reverse case. As the VTCF converts to a fully open configuration, the flow resistance gradually decreases to that of no filter. This work shows that even very thin VTCF arms can result in the viscous block effect and may cause significant hemodynamic impacts on clot capture, potential thrombosis and flow impedance inside the IVC. The present study also shows that CFD is a valuable and feasible in silico tool for analyzing the IVC filter hemodynamics to complement in vivo clinical and in vitro experimental studies.

Inferior Vena Cava Filters: Past, Present, and Future

Inferior vena cava (IVC) filters have existed as a treatment option for VTE for decades. Advances in medical technology have provided physicians with several options for devices that can be placed on either a permanent or temporary basis; however, there are limited data from randomized, controlled trials on the appropriate use of IVC filters. This contemporary review summarizes the history of IVC filters and the types that are available in clinical practice. It reviews the literature on the use of IVC filters and discusses the indications that professional societies have endorsed for their use. In addition, it outlines the complications of IVC filter placement and future research directions.

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.

Radiologists' Field Guide to Retrievable and Convertible Inferior Vena Cava Filters

OBJECTIVE. Inferior vena cava (IVC) filters are commonly used in patients who are at risk for life-threatening pulmonary embolism. After the introduction of permanent devices, numerous retrievable and convertible designs became available. Inaccurate identification can lead to confusion in options for filter retrieval and anticoagulation. CONCLUSION. This article highlights device designs of retrievable and convertible IVC filters to assist interpretation of diagnostic studies.

Inferior Vena Cava Filters: Why, Who, and for How Long?

Vena cava filters are implantable devices that are placed to trap thrombus originating in the lower extremities and prevent it from migrating to the lungs. In general, inferior vena cava (IVC) filters are indicated for patients who cannot receive anticoagulation. Other indications for IVC filtration are less clear, and guidelines vary. All patients who have a retrievable IVC filter should be followed, and the removal of the IVC filter should be considered once its indication is lost.

A comparative CFD study of four inferior vena cava filters

Computational fluid dynamics was used to simulate the flow of blood within an inferior vena cava (IVC) geometry model that was reconstructed from computed tomography images obtained from a real patient. The main novelty of the present work is that we simulated the implantation of 4 different filter models in this realistic IVC geometry. We considered different blood flow rates in the range between V_in =20 and V_in =80 cm³ /s, and all simulations were performed with both the Newtonian and a non-Newtonian model for the blood viscosity. We compared the hemodynamics performance of the different filter models, and we paid a special attention to the total drag force, F_d , exerted by the blood flow on the filter surface. This force is the sum of 2 contributions: the viscous skin friction force, which was found to be roughly proportional to the filter surface area, and the pressure force, which depended on the particular filter geometry design. The F_d force is relevant because it must be balanced by the total force exerted by the filter hooks/struts on the IVC wall at the attachment locations. For the highest V_in value investigated, the variation in F_d among filters was from 116 to 308 dyne. We also showed how the present results can be extrapolated to obtain good estimates of the drag forces if the blood viscosity levels change, ie, if the patient with a filter implanted is treated with anticoagulant therapy.