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

Which caval diameter? Clarification manufacturer's instructions for inferior vena cava filter use and implications for practice

AIM

To clarify manufacturer's instructions for inferior vena cava (IVC) filter use and implications for practice.

MATERIALS AND METHODS

Three vendors of IVC filters were contacted for clarification, with all stating that caval diameter limits are to be true maximum and true minimum cross-sectional diameters. To determine the implications of this, measurements were performed on 302 abdominal computed tomography studies in four transaxial dimensions perpendicular to the long axis including true maximum and minimum diameters, and measurements reflecting those typically taken on fluoroscopic cavography.

RESULTS

Based on the true maximum and true minimum caval diameter limits as clarified by vendors, 22% of patients who would typically be considered suitable for IVC filter insertion based on frontal and lateral fluoroscopic cavography would be contraindicated, and 40% of patients who would typically be considered suitable for IVC filter insertion based on only frontal fluoroscopic cavography (as lateral projection is often not performed) would be contraindicated.

CONCLUSION

There is a marked discordance between the vendor-clarified caval diameter limits of three common IVC filter devices and real-world caval geometry. Given the rarity of complications, this suggests a pressing need for revision of manufacturers' instructions for use statements to better reflect current safe routine clinical use, particularly from a medicolegal perspective.

Outcomes of bellwether cases related to inferior vena cava filters in multidistrict litigations

OBJECTIVE

In the present study, we identified and reviewed the outcomes of bellwether cases related to inferior vena cava (IVC) filter multidistrict litigations (MDLs).

METHODS

The legal research database, LexisNexis (New York, NY), was used to identify all cases related to IVC filters. Cases unrelated to the MDLs were excluded. Court documents recording the proceedings for bellwether cases sent to jury trials were retrieved from the LexisNexis subsidiary, Law360. Data on plaintiffs, filter models, reported complications, filed claims, decision-making body, verdicts, and rewards were reviewed.

RESULTS

A total of 678 cases pertaining to IVC filters were found in the database, of which 12 were identified as bellwether cases for MDL. Of the 12, 2 (16.7%) were initially ruled in favor of the plaintiffs in jury trials, although the judgment for 1 of these was later vacated by a judge. The remaining 10 (83.3%) had been decided in favor of the manufacturers by judges and juries.

CONCLUSIONS

Verdicts in all bench trials were in favor of manufacturers, suggesting that judges perceived the presented complications by patients to be within the normal realm of the expected risk of IVC filter use. The findings from the present study have emphasized the treating physicians' legal responsibility to adequately warn patients of all the associated risks with IVC filters. The findings have also indicated that physicians can still be found liable in product liability cases directed at manufacturers. Physicians should continue to actively monitor patients to optimize the IVC retrieval windows.

Evaluation of hemodynamic effects of different inferior vena cava filter heads using computational fluid dynamics

Inferior vena cava (IVC) filters are used to prevent pulmonary embolism in patients with deep vein thrombosis for whom anticoagulation is unresponsive. The head is a necessary structure for an Inferior vena cava filter (IVCF) in clinic use. At present, there are various head configurations for IVCFs. However, the effect of head pattern on the hemodynamics of IVCF is still a matter of unclear. In this study, computational fluid dynamics is used to simulate non-Newtonian blood flows around four IVCFs with different heads inside an IVC model, in which the Denali filter with a solid and hooked head is employed as a prototype, and three virtual variants are reconstructed either with a no-hook head or with a through-hole head for comparison. The simulation results show that the through-hole head can effectively avoid the recirculation region and weaken the blood flow stasis closely downstream the IVCF head. The shape change of the filter head has no significant effect on the blood flow acceleration inside the IVCF cone as well as little influence on the wall shear stress (WSS) distribution on the filter wire surface and IVC wall. The structure pattern of filter head greatly affects the flow resistance of its own. However, the flow drag of filter head only occupies a small proportion of the total resistance of IVCF. Therefore, to reduce the flow resistance of an IVCF should optimize its whole structure.

Ibero-American Society of Interventionism (SIDI) and the Spanish Society of Vascular and Interventional Radiology (SERVEI) Standard of Practice (SOP) for the Management of Inferior Vena Cava Filters in the Treatment of Acute Venous Thromboembolism

Objectives: to present an interventional radiology standard of practice on the use of inferior vena cava filters (IVCFs) in patients with or at risk to develop venous thromboembolism (VTE) from the Iberoamerican Interventional Society (SIDI) and Spanish Vascular and Interventional Radiology Society (SERVEI). Methods: a group of twenty-two interventional radiologist experts, from the SIDI and SERVEI societies, attended online meetings to develop a current clinical practice guideline on the proper indication for the placement and retrieval of IVCFs. A broad review was undertaken to determine the participation of interventional radiologists in the current guidelines and a consensus on inferior vena cava filters. Twenty-two experts from both societies worked on a common draft and received a questionnaire where they had to assess, for IVCF placement, the absolute, relative, and prophylactic indications. The experts voted on the different indications and reasoned their decision. Results: a total of two-hundred-thirty-three articles were reviewed. Interventional radiologists participated in the development of just two of the eight guidelines. The threshold for inclusion was 100% agreement. Three absolute and four relative indications for the IVCF placement were identified. No indications for the prophylactic filter placement reached the threshold. Conclusion: interventional radiologists are highly involved in the management of IVCFs but have limited participation in the development of multidisciplinary clinical practice guidelines.

Efficacy and safety of rivaroxaban in patients with inferior vena cava filter placement without anticoagulation contraindications (EPICT): a prospective randomised controlled trial study protocol

INTRODUCTION

Inferior vena cava (IVC) filters are commonly used in patients with venous thromboembolism to prevent fatal pulmonary embolism, but the thrombosis risk increases after filter placement. Warfarin is a widely anticoagulant, but long-term monitoring and dose adjustments are required. Anticoagulation with rivaroxaban is more straightforward as it dose not require laboratory monitoring. This study compares the efficacy and safety of rivaroxaban and warfarin as an in anticoagulation therapy for patients with IVC filter placement.

METHODS AND ANALYSIS

This is a multicentre, randomised controlled trial. In total, 200 patients with deep vein thrombosis (DVT) with IVC filter implantation from 10 hospitals will be recruited. The patients will be randomised to the experimental group (rivaroxaban) or the control group (nadroparin overlapped with warfarin). The primary outcomes include death of any cause, pulmonary embolism (PE)-related death, bleeding and recurrent PE/DVT. The secondary outcomes include the percentage of other vascular events, IVC filter retrieval failure and net clinical benefits. This study aims to provide reliable, verification for the efficacy and safety of rivaroxaban antithrombotic therapy after IVC filter placement.

ETHICS AND DISSEMINATION

The study was approved by the Human Research Ethics Committee of the Second Affiliated Hospital of Zhejiang University School of Medicine (approval number: (2019) 295). The results will be disseminated through presentations at scientific conferences and publications in peer-reviewed journals TRIAL REGISTRATION NUMBER: NCT04066764.

IVC filter retrieval: a multicenter proposal of two score systems to predict application of complex technique and procedural outcome

PURPOSE

Aim of this study was to identify preprocedural parameters, which may predict the application of a complex IVC filter retrieval technique and estimate the procedural outcome by applying two dedicated score systems.

MATERIALS AND METHODS

In this retrospective multicenter analysis, data concerning patient, filter and procedure characteristics were retrieved from January 2018 to March 2020. Patients were evaluated according to the retrieval technique (standard vs. complex) and the procedural outcome (success vs. failure). Significant differences among these groups were evaluated, and two score systems were developed to predict the application of a complex retrieval technique and the procedural outcome.

RESULTS

One hundred and sixteen IVC filters were retrieved in 116 patients. In 98 subjects, the filter was retrieved with a standard procedure (Standard group, 84.5% vs. Complex group, 15.5%), while in 106 patients the procedure was successful (Success group, 91.4% vs. Failure group, 8.6%). Statistically significant differences were noted in terms of embedded filter hook, filter apex tilt, angle between filter axis and IVC, caval wall penetration, dwelling time and procedural time. Two score 0-5 points to predict the need for a complex retrieval technique and the procedural outcome were developed, with a prognostic accuracy of 88.8% and 91.4%, respectively.

CONCLUSION

Significant differences were appreciable analyzing the sample data comparing both the retrieval technique applied and the procedural outcome. Two predictive scores were developed to assess the need for applying a complex retrieval technique and to estimate the procedural outcome.

Meta-Analysis of the Usefulness of Inferior Vena Cava Filters in Massive and Submassive Pulmonary Embolism

To conduct a systematic review and meta-analysis evaluating the safety and effectiveness of inferior vena cava filter (IVCF) placement in the setting of massive and submassive pulmonary embolism (PE), Pubmed and Cochrane Library were queried to identify all clinical studies evaluating IVCF placement in patients with massive and submassive PE from database establishment to December 2019. The rate of recurrent PE, PE-related mortality, adverse events, IVCF type, additional treatment intervention, DVT status, and follow-up length were retrieved. Recurrent PE, mortality, and complication rates were pooled. Meta-analysis was performed to compare mortality rates between groups with and without IVCF placement. Subgroup analysis was performed based on whether catheter-directed therapy was used for PE intervention. Fifteen observational studies with a total of 232 patients who received IVCF for submassive or massive PE were included. The pooled overall recurrent symptomatic PE and mortality rates were 1.4% and 5.5%, respectively. A lower mortality rate among patients with IVCF was observed than those without (6.8% vs 26.3%; odds ratio [OR] 0.275 [95% confidence interval] 0.090 to 0.839], I² = 30.6%, p = 0.023). Patients who received concurrent catheter-directed therapy demonstrated a lower recurrent PE (0% vs 2.8%) and mortality rate (3.4% vs 7.8%) than those who did not. The cumulative IVCF-related complication rate was 0.63%. In conclusion, based on a limited amount of low-quality evidence, IVCF placement is associated with low recurrent PE and PE-related mortality rates among patients with massive and submassive PE, suggestive of a potential clinical benefit in this scenario. Prospectively designed studies are warranted to confirm these findings.