Inferior vena cava filters

Optimizing inferior vena cava filter design: A computational fluid dynamics study on strut configuration for enhanced hemodynamic performance and thrombosis reduction

Background and objective

Inferior vena cava filters have been shown to be effective in preventing deep vein thrombosis and its secondary complication, pulmonary embolism, thereby reducing the high mortality rate. Although inferior vena cava filters have evolved, specific complications like inferior vena cava thrombosis-induced deep vein thrombosis worsening and recurrent pulmonary embolism continue to pose challenges. This study analyzes the effects of geometric parameter variations of inferior vena cava filters, which have a significant impact on the thrombus formation inside the filter, the capture, dissolution, and hemodynamic flow of thrombus, as well as the shear stress on the filter and vascular wall.

Methods

This study used computational fluid dynamic simulations with the carreau model to investigate the impact of varying inferior vena cava filter design parameters (number of struts, strut arm length, and tilt angle) on hemodynamics.

Results

Recirculation and stagnation areas due to flow velocity and pressure, along with wall shear stress values, were identified as key factors. It is important to find a balance between wall shear stress high enough to aid thrombolysis and low enough to prevent platelet activation. The results of this paper show that the risk of platelet activation and thrombus filtration may be lowest when the wall shear stress of the filter ranges from 0 to 4 [Pa], minimizing stress concentration within the filter.

Conclusion

16 arm struts with a length of 20 mm and a tilt angle of 0° provide the best balance between thrombus capture and minimization of hemodynamic disturbance. This configuration minimizes the size of the stagnation and recirculation zones while maintaining sufficient wall shear stress for thrombus dissolution.

[Translation into French and republication of: "Recurrent venous thromboembolism in anticoagulated cancer patients: diagnosis and treatment"]

Patients with cancer are at significantly increased risk of venous thromboembolism (VTE), due both to the impact of malignant disease itself and to the impact of certain anticancer drugs on haemostasis. This is true both for first episode venous thromboembolism and recurrence. The diagnosis and management of VTE recurrence in patients with cancer poses particular challenges, and these are reviewed in the present article, based on a systematic review of the relevant scientific literature published over the last decade. Furthermore, it is uncertain whether diagnostic algorithms for venous thromboembolism, validated principally in untreated non-cancer patients, are also valid in anticoagulated cancer patients: the available data suggests that clinical decision rules and D-dimer testing perform less well in this clinical setting. In patients with cancer, computed tomography pulmonary angiography and venous ultrasound appear to be the most reliable diagnostic tools for diagnosis of pulmonary embolism and deep vein thrombosis respectively. Options for treatment of venous thromboembolism include low molecular weight heparins (at a therapeutic dose or an increased dose), fondaparinux or oral direct factor Xa inhibitors. The choice of treatment should take into account the nature (pulmonary embolism or VTE) and severity of the recurrent event, the associated bleeding risk, the current anticoagulant treatment (type, dose, adherence and possible drug-drug interactions) and cancer progression.

Recurrent Deep Vein Thrombosis (DVT) and Inferior Vena Cava (IVC) Filter: Should a Computed Tomography (CT) Venogram and Inferior Vena Cavagram Be the Standard of Care?

A pulmonary embolism (PE) is a life-threatening complication of deep vein thrombosis (DVT). Although timely anticoagulation is the first-line treatment for DVT, an inferior vena cava (IVC) filter can be considered when anticoagulation is contraindicated. Unfortunately, IVC filters come with complications of their own, including thrombus formation in or around the filter. An 89-year-old man with a past medical history of coronary artery disease, congestive heart failure, chronic obstructive pulmonary disease, and prior DVT status post IVC filter implantation five years ago in 2018 presented with hypotension, dizziness, and syncope. Computed tomography angiography (CTA) of the chest showed bilateral PEs. Venous Doppler ultrasound of the bilateral lower extremities was negative for DVT. CT venogram was performed; however, the contrast filling was suboptimal and as such, a venous thrombosis could not be ruled out. Therefore, an inferior vena cavagram was performed through the right common femoral vein and confirmed a large thrombus positioned cephalad to the IVC filter. A thrombectomy was performed and the IVC filter was replaced given the patient was at high risk for venous thromboembolism recurrence and complications.  Although an IVC filter offers some protection from recurrent PEs, it does have risks and complications. As seen in our patient, the IVC filter can be a nidus for the formation of a thrombus which has the risk of dislodging. When evaluating a patient for the source of a PE, it is important to consider prior IVC implant and perform further workups, such as a CT venogram or an inferior vena cavagram, to evaluate for thrombus in or around the filter.

Comparison of inferior vena cava filter use and outcomes between cancer and non-cancer patients in a tertiary hospital

BACKGROUND

While accepted indications for the use of inferior vena cava filter (IVCF) in patients with a venous thromboembolism (VTE) have remained stable, their use continues to be frequent. Retrieval rates are still low, being particularly notable in the population with cancer. This study aims to review the rate of adherence to guidelines recommendation and to compare retrieval rates and complications in both cancer and non-cancer patients.

METHODS

A retrospective study was performed including 185 patients in whom an IVCF was placed in Hospital Clinic of Barcelona. Baseline characteristics, clinical outcomes, and IVCF-related outcomes were analyzed. A strongly recommended indication (SRI) was considered if it was included in all the revised clinical guidelines and non-strongly if it was included in only some.

RESULTS

Overall, 47 % of the patients had a SRI, without differences between groups. IVCF placement after 29 days from the VTE event was more frequent in the cancer group (46.1 vs. 17.7 %). Patients with cancer (48.1 % of the cohort) were older, with higher co-morbidity and bleeding risk. Anticoagulation resumption (75.3 % vs. 92.7 %) and IVCF retrieval (50.6 % vs. 66.7 %) were significantly less frequent in cancer patients. No significant differences were found regarding IVCF-related complications, hemorrhagic events and VTE recurrence.

CONCLUSIONS

SRI of IVCF placement was found in less than half of the patients. Cancer patients had higher rates of IVCF placement without indication and lower anticoagulation resumption and IVCF retrieval ratios, despite complications were similar in both groups.

Successful retrieval of tip-embedded inferior vena cava filter using a modified forceps technique: case report

BACKGROUND

The retrieval of inferior vena cava (IVC) filter is essential for preventing complications associated with the device. Advanced techniques have been developed to improve the success rate of retrieving tip-embedded filters. The forceps technique is frequently used to address this issue.

CASE PRESENTATION

We present a case study of two patients who underwent a successful tip-embedded IVC filter retrieval using a modified forceps technique, which has not been previously reported. This technique involves using a wire loop under the filter tip and a forceps to grasp the filter shoulder. By pulling the wire loop and pushing the forceps in counterforce, the filter tip is straightened and aligned with the vascular sheath. The vascular sheath can then dissect the filter tip out from the caval wall and get inside the sheath to complete the retrieval.

CONCLUSIONS

The modified forceps technique we present here offers a new solution for the complex retrieval of IVC filters.

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.

IVC filter - assessing the readability and quality of patient information on the Internet

OBJECTIVE

The internet is an increasingly favorable source of information regarding health-related issues. The aim of this study is to apply appropriate evaluation tools to assess the evidence available online about inferior vena cava (IVC) filters with a focus on quality and readability.

METHODS

A search was performed during December 2022 using three popular search engines, namely Google, Yahoo, and Bing. Websites were categorized into academic, physician, commercial, and unspecified websites according to their content. Information quality was determined using Journal of the American Medical Association (JAMA) criteria, the DISCERN scoring tool, and whether a Health On the Net Foundation certification (HONcode) seal was present. Readability was established using the Flesch Reading Ease Score (FRES) and Flesch-Kincaid Grade Level (FKGL). Statistical significance was accepted as P < .05.

RESULTS

In total, 110 websites were included in our study. The majority of websites were categorized as commercial (25%), followed by hospital (24%), academic (21%), unspecified (16%), and physician (14%). Average scores for all websites using JAMA and DISCERN were 1.93 ± 1.19 (median, 1.5; range, 0-4) and 45.20 ± 12.58 (median, 45.5; range, 21-75), respectively. The highest JAMA mean score of 3.07 ± 1.16 was allocated to physician websites, and the highest DISCERN mean score of 52.85 ± 12.66 was allocated to hospital websites. The HONcode seal appeared on two of the selected websites. Physician, hospital, and unspecified websites had a significantly higher mean JAMA score than academic and commercial websites (all with P < .001). Hospital websites had a significantly higher mean DISCERN score than academic (P = .007), commercial (P < .001), and unspecified websites (P = .017). Readability evaluation generated a mean FRES score of 51.57 ±12.04, which represented a 10th to 12th grade reading level and a mean FKGL score of 8.20 ± 1.70, which represented an 8th to 10th grade reading level. Only 12 sources were found to meet the ≤6th grade target reading level. No significant correlation was found between overall DISCERN score and overall FRES score.

CONCLUSIONS

The study results demonstrate that the quality of online information about IVC filters is suboptimal, and academic and commercial websites, in particular, must enhance their content quality regarding the use of IVC filters. Considering the discontinuation of the HONcode as a standardized quality assessment marker, it is recommended that a similar certification tool be developed and implemented for the accreditation of patient information online.

Venous Thromboembolism: Review of Clinical Challenges, Biology, Assessment, Treatment, and Modeling

Venous thromboembolism (VTE) is a massive clinical challenge, annually affecting millions of patients globally. VTE is a particularly consequential pathology, as incidence is correlated with extremely common risk factors, and a large cohort of patients experience recurrent VTE after initial intervention. Altered hemodynamics, hypercoagulability, and damaged vascular tissue cause deep-vein thrombosis and pulmonary embolism, the two permutations of VTE. Venous valves have been identified as likely locations for initial blood clot formation, but the exact pathway by which thrombosis occurs in this environment is not entirely clear. Several risk factors are known to increase the likelihood of VTE, particularly those that increase inflammation and coagulability, increase venous resistance, and damage the endothelial lining. While these risk factors are useful as predictive tools, VTE diagnosis prior to presentation of outward symptoms is difficult, chiefly due to challenges in successfully imaging deep-vein thrombi. Clinically, VTE can be managed by anticoagulants or mechanical intervention. Recently, direct oral anticoagulants and catheter-directed thrombolysis have emerged as leading tools in resolution of venous thrombosis. While a satisfactory VTE model has yet to be developed, recent strides have been made in advancing in silico models of venous hemodynamics, hemorheology, fluid-structure interaction, and clot growth. These models are often guided by imaging-informed boundary conditions or inspired by benchtop animal models. These gaps in knowledge are critical targets to address necessary improvements in prediction and diagnosis, clinical management, and VTE experimental and computational models.

Recurrent venous thromboembolism in anticoagulated cancer patients: Diagnosis and treatment

Patients with cancer are at significantly increased risk of venous thromboembolism (VTE), due both to the impact of malignant disease itself and to the impact of certain anticancer drugs on haemostasis. This is true both for first episode venous thromboembolism and recurrence. The diagnosis and management of VTE recurrence in patients with cancer poses particular challenges, and these are reviewed in the present article, based on a systematic review of the relevant scientific literature published over the last decade. Furthermore, it is uncertain whether diagnostic algorithms for venous thromboembolism, validated principally in untreated non-cancer patients, are also valid in anticoagulated cancer patients: the available data suggests that clinical decision rules and D-dimer testing perform less well in this clinical setting. In patients with cancer, computed tomography pulmonary angiography and venous ultrasound appear to be the most reliable diagnostic tools for diagnosis of pulmonary embolism and deep vein thrombosis respectively. Options for treatment of venous thromboembolism include low molecular weight heparins (at a therapeutic dose or an increased dose), fondaparinux or oral direct factor Xa inhibitors. The choice of treatment should take into account the nature (pulmonary embolism or VTE) and severity of the recurrent event, the associated bleeding risk, the current anticoagulant treatment (type, dose, adherence and possible drug-drug interactions) and cancer progression.

Extensive Iliocaval Deep Vein Thrombosis Provoked by Coronavirus Disease 2019 (COVID-19) in the Setting of an Inferior Vena Cava Filter

Thrombotic events are well-known complications of coronavirus disease 2019 (COVID-19). Inferior vena cava filters (IVCF) are devices used to prevent pulmonary embolism (PE) and also increase the risk of thrombotic complications. Here, we describe the case of a 38-year-old female with extensive bilateral lower extremity deep vein thrombosis (DVT) and thrombosis of the infrarenal inferior vena cava (IVC) in the setting of an IVCF and symptomatic COVID-19. The IVCF had been placed a few months prior for a left femoral DVT and PE after spinal surgery. This patient was treated with pharmacomechanical thrombectomy and ultrasound-assisted thrombolysis followed by angioplasty and anticoagulation. The IVCF was retrieved after confirming there was no residual DVT when the patient recovered from COVID-19 infection. This case of a rare combination of IVCF-related thrombosis secondary to COVID-19 highlights the potential pitfalls of IVCF in this situation.

Intravascular Tumor Extension and Pulmonary Tumor Embolism in Children With Solid Malignancies: Is There a Role for Inferior Vena Cava Filters?

Intravascular tumor extension is an uncommon complication of solid malignancies that, when present in the inferior vena cava (IVC), can result in fatal pulmonary tumor embolism. Currently, neoadjuvant chemotherapy and surgery are the mainstays of treatment; however, there are no consensus guidelines for management. We describe three cases of pediatric solid malignancies with associated IVC extension and pulmonary tumor embolism. We hypothesize that there is scope for IVC filter placement in such cases to mitigate the risk of fatal pulmonary tumor embolism.

Do Prophylactic Inferior Vena Cava Filters Affect the Rates of Venous Thromboembolism and Pulmonary Embolism in Patients Undergoing Major Spine Surgery?

STUDY DESIGN

Retrospective Analysis.

BACKGROUND

Venous thromboembolism (VTE) represents a significant cause of morbidity and mortality in major spine surgery. Placement of prophylactic inferior vena cava filters (IVCF) in patients undergoing major spine surgery was previously adopted at our institution. This study reports our experience and compares VTE rates between patients with and without preoperative IVCF placement.

METHODS

A Retrospective comparative study was conducted on adult patients who underwent IVCF placement and those who did not prior to their spinal fusion procedure, between 2013 and 2016. Thoracolumbar fusions (anterior and/or posterior) of 7 or more levels, spinal osteotomies, and a minimum of a 3-month follow-up were included. Traumatic, oncologic, and cervical pathology were excluded. Primary outcomes measured included the incidence of overall VTE (DVT/PE), death, IVCF related complications, and IVCF retrieval.

RESULTS

386 patients who underwent major spine surgery, 258 met the eligibility criteria. Of those patients, 105 patients (40.7%) had prophylactic IVCF placement. All patients had postoperative SCDs and chemoprophylaxis. The presence of an IVCF was associated with an increased rate of overall VTE (14.3% vs 6.5%, P ≤ .05) and DVT episodes (8.6% vs 2.6%, P = .04). The rate of PE for the IVCF group and non-IVCF group was 8.6% and 4.6%, respectively, which was not statistically significant (P = .32). The all-cause mortality rate overall of 2.3% was statistically similar between both groups (P = 1.0). The IVCF group had higher rates of hematoma/seroma vs the non-IVCF group (12.4% vs 3.9%, P ≤ .05). 99 IVCFs were retrievable designs, and 85% were successfully retrieved. Overall IVCF-related complication rate was 11%.

CONCLUSIONS

No statistical difference in PE or mortality rates existed between the IVCF and the control group. Patients with IVCF placement experienced approximately twice the rate of VTE and three times the rate of DVT compared to those without IVCF. The IVCF-related complication rate was 11%. Based on the results of this study, the authors recommend against the routine use of prophylactic IVCFs in adults undergoing major spine surgery.

LEVEL OF EVIDENCE

III.

Effect of access site choice on inferior vena cava filter angulation and outcomes

BACKGROUND

In the present study, we compared the outcomes of inferior vena cava (IVC) filter placement between the femoral vein (FV) and internal jugular (IJ) vein access sites.

METHODS

We performed a retrospective study using the Vascular Quality Initiative database to assess patients who had undergone IVC filter placement from 2013 to 2019. The patients were placed into two groups according to the access site location: FV and IJ vein. The FV group included patients with access via the right and left FVs and other leg veins, and the IJ group included patients with access via the right or left IJ vein. The primary outcome was the rate of filter angulation. The secondary outcomes included access site complications such as deep vein thrombosis, hematoma, and bleeding requiring transfusion.

RESULTS

Of 13,221 patients, 8214 (63%) had undergone IVC filter placement via FV access and 4789 (37%) via IJ access. The remaining 218 patients had had an unknown access site or were excluded. Within the IJ group, 4696 (98.0%) had undergone access via the right IJ and 93 (2%) via the left IJ. Within the FV (common femoral, femoral, or other infrainguinal veins) group, 7007 (85.3%) had undergone access via the right FV and 1207 (14.6%) via the left FV. The mean patient age was 63 ± 15.9 years, the mean body mass index was 30.9 ± 9.60 kg/m², and 6788 of the patients were men (52.0%). The most common indication for filter placement was a contraindication to anticoagulation because of a recent or active bleeding episode (30%), followed by planned surgery (22%), new deep vein thrombosis/pulmonary embolism (7%), fall risk (5%), and trauma (4%). Infrarenal filters had been placed in 97.9% of the patients. Univariate analysis identified body mass index and suprarenal placement as independent risk factors for angulation. The final multivariate analysis showed a significant increase in angulation (0.9% vs 0.34%; odds ratio, 1.46; 95% confidence interval, 1.02-2.11; P = .04) and increased access site complications (0.25% vs 0.07%; odds ratio, 2.068; 95% confidence interval, 1.01-4.23; P = .048) in the FV access group. No significant correlation between the access site and retrieval rate was found (P = .9270).

CONCLUSIONS

Placement of IVC filters via IJ access showed a lower rate of filter angulation in the IVC and fewer access site complications compared with FV access.

Multi-factor analysis of failure for modified single-session Angiojet rheolytic thrombectomy in treatment of acute iliofemoral venous thrombosis from iliac vein compression syndrome

PURPOSE

To explore the risk factors of failure for modified single-session Angiojet rheolytic thrombectomy combined with directed iliac vein stenting, directed filter retrieval in the treatment of iliac vein compression with iliofemoral vein thrombosis.

METHODS

During September 2017 to September 2021, 278 patients with DVT were retrospectively analyzed and 203 were eligible for inclusion. All patients were tried to take modified single-session Angiojet rheolytic thrombectomy combined with directed iliac vein stenting, directed filter retrieval treatment. The perioperative factors were analyzed between groups: group 1-modified single-session therapy succeed, and group 2-modified single-session therapy failed. The high risk factors of failure group were evaluated by logistic regression analysis.

RESULTS

48 patients failed in modified single-session therapy, up to 23.64%. Single factor analysis indicated that there were five independent risk factors related with the failure (p < 0.05), including course of disease longer than 7 days, lumbar degeneration-related iliac vein compression syndrome (dIVCS), antegrade vein access, balloon-assisted cracking thrombus, and suction time. Logistic regression analysis indicated that course of disease longer than 7 days (OR = 19.642.95%CI:6.776∼56.933), dIVCS (OR = 11.586.95%CI:4.016∼33.427) were high risk factors for modified single-session therapy failed, antegrade vein access (OR = 0.171.95%CI:0.047∼0.614) and balloon-assisted cracking thrombus (OR = 0.157.95%CI:0.045∼0.542) were protective factors for therapy failure (p < 0.05).

CONCLUSIONS

Long course of disease and dIVCS are the high risk factors for failure of modified single-session Angiojet rheolytic thrombectomy combined with directed iliac vein stenting, directed filter retrieval in the treatment of iliac vein compression syndrome (IVCS). But, antegrade vein access and balloon-assisted cracking thrombus intraoperatively may improve the success rate of modified single-session treatment.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Retrievable Inferior Vena Cava Filters-Use, Removal, and Removal Techniques

The use of retrievable inferior vena cava filters is on the rise, but there is an inadequate number of these filters being removed even if their use as a prophylactic for venous thromboembolism is no longer indicated. Complications with retrievable filters that remain in the patient for an extended duration include examples such as filter tilt and embedding into the caval wall. This raises concerns for whether the filter is properly functioning and for consequent sequelae, including recurrent thrombosis, stenosis, or inferior vena cava perforation. With these complications, there are also challenges to retrieving these filters via the standard techniques and thus more advanced techniques are required. Both standard and advanced techniques, their uses, and possible risks of these methods are also discussed.

Nano-embedded medical devices and delivery systems in interventional radiology

Nanomaterials research has significantly accelerated the development of the field of vascular and interventional radiology. The incorporation of nanoparticles with unique and functional properties into medical devices and delivery systems has paved the way for the creation of novel diagnostic and therapeutic procedures for various clinical disorders. In this review, we discuss the advancements in the field of interventional radiology and the role of nanotechnology in maximizing the benefits and mitigating the disadvantages of interventional radiology theranostic procedures. Several nanomaterials have been studied to improve the efficacy of interventional radiology interventions, reduce the complications associated with medical devices, improve the accuracy and efficiency of drug delivery systems, and develop innovative imaging modalities. Here, we summarize the recent progress in the development of medical devices and delivery systems that link nanotechnology in vascular and interventional radiology. This article is categorized under: Diagnostic Tools > Diagnostic Nanodevices Diagnostic Tools > In Vivo Nanodiagnostics and Imaging Therapeutic Approaches and Drug Discovery > Nanomedicine for Cardiovascular Disease.

Catheter-Directed Interventions for the Treatment of Lower Extremity Deep Vein Thrombosis

Lower extremity deep vein thrombosis (DVT) leads to significant morbidity including pain, swelling, and difficulty walking in the affected limb. If left untreated, DVT increases the risk of pulmonary embolism (PE), recurrent venous thromboembolism (VTE), and post thrombotic syndrome (PTS). The objective of this review was to identify catheter-directed interventions and their success rates for the treatment of lower extremity DVT. A comprehensive search of current and emerging catheter-directed interventions for lower extremity DVT treatment was conducted in PubMed and Google Scholar. Clinical trials, retrospective and prospective observational studies, and case reports were identified to classify percutaneous mechanical thrombectomy (PMT), catheter-directed thrombolysis (CDT), and pharmacomechanical CDT (PCDT) devices based on their mechanism of action and indication of use. Catheter-directed interventions such as PMT, CDT, and PCDT offer an alternative therapeutic strategy for DVT management, particularly in patients with limb-threatening conditions and absolute contraindications to anticoagulants. Currently, there are limited guidelines for the use of mechanical and pharmacomechanical devices because of the lack of clinical evidence available for their use in treatment. Future studies are required to determine the short and long-term effects of using catheter-directed interventions as well as their effectiveness in treating acute versus subacute and chronic DVT.

Inferior vena cava filters in pregnancy: Safe or sorry?

Background

Potential hazards of vena cava filters include migration, tilt, perforation, fracture, and in-filter thrombosis. Due to physiological changes during pregnancy, the incidence of these complications might be different in pregnant women.

Aim

To evaluate the use and safety of inferior vena cava filters in both women who had an inferior vena cava filter inserted during pregnancy, and in women who became pregnant with an inferior vena cava filter in situ.

Methods

We performed two searches in the literature using the keywords “vena cava filter”, “pregnancy” and “obstetrics”.

Results

The literature search on women who had a filter inserted during pregnancy yielded 11 articles compiling data on 199 women. At least one filter complication was reported in 33/177 (19%) women and included in-filter thrombosis (n = 14), tilt (n = 6), migration (n = 5), perforation (n = 2), fracture (n = 3), misplacement (n = 1), air embolism (n = 1) and allergic reaction (n = 1). Two (1%) filter complications led to maternal deaths, of which at least one was directly associated with a filter insertion. Filter retrieval failed in 9/149 (6%) women. The search on women who became pregnant with a filter in situ resulted in data on 21 pregnancies in 14 women, of which one (6%) was complicated by uterine trauma, intraperitoneal hemorrhage and fetal death caused by perforation of the inferior vena cava filter.

Conclusion

The risks of filter complications in pregnancy are comparable to the nonpregnant population, but could lead to fetal or maternal death. Therefore, only in limited situations such as extensive thrombosis with a contraindication for anticoagulants, inferior vena filters should be considered in pregnant women.

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.

Diagnosis and treatment strategies for intraoperative pulmonary embolism caused by renal tumor thrombus shedding

AIM

To provide an overview of techniques for prevention, immediate diagnosis, and treatment strategies of intraoperative pulmonary embolism caused by renal tumor thrombus shedding.

METHODS

A total of 290 patients admitted into our medical center from March 2015 to May 2021 were retrospectively analyzed. All patients underwent radical nephrectomy with tumor thrombectomy. Six patients were diagnosed as pulmonary embolism during the perioperative period, of which two patients had tumor thrombus shedding. One patient underwent thoracotomy and thrombectomy, one patient underwent interventional thrombectomy, and four patients underwent conservative treatment. All patients have gone through our diagnosis and strategy flow chart. Demographic data, tumor characteristics, tumor thrombus characteristics, and follow-up data were collected.

RESULTS

In the preoperative risk factor assessment, of the 253 patients who entered the follow-up, 163 were women, 48 were older than 60 years old, and 83 had a duration of more than 2 months. In addition, 27 patients had tumor thrombus with bland thrombus, and 43 patients had floating tumor thrombus. 78 patients underwent postoperative anticoagulation after evaluation. The average follow-up time was 23.3  ± $\pm $  8.6 months (range, 7-31 months). All patients were alive during the follow-up period.

CONCLUSION

For acute pulmonary embolism during nephrectomy and tumor thrombectomy, management strategies can be used to deal with intraoperative emergencies and provide reference.

A retrospective cohort study assessing the incidence of inferior vena cava (IVC) occlusion following prophylactic IVC filter insertion: Is anticoagulation necessary during filter dwell?

BACKGROUND

Inferior vena cava (IVC) filters play a role in preventing venous thromboembolism after major trauma where deep venous thrombosis (DVT) risk is up to 80%. It has been suggested that IVC filters are thrombogenic and many patients are therefore placed on therapeutic anticoagulation during IVC filter dwell citing concern of in situ IVC thrombosis, even in the absence of existing DVT.

METHODS

Between 1 June 2018 and 31 December 2021, this retrospective study assessed the incidence of IVC thrombosis following prophylactic IVC filter insertion. Groups were defined according to the presence or absence of therapeutic anticoagulation during filter dwell. The primary outcome was the presence or absence of IVC thrombus at retrieval.

RESULTS

A total of 124 patients were included. Anticoagulation was prescribed in 29 and anticoagulation was not prescribed in 63. A further 32 patients developed a new thrombosis episode after the prophylactic IVC filter was placed, and 29 were prescribed anticoagulation part-way during filter dwell as a result of this diagnosis. No cases of IVC occlusion were observed in any patient group.

CONCLUSIONS

Caval thrombosis was not observed after prophylactic filter placement, with or without the prescription of anticoagulation. While prospective trials are needed to increase the level of evidence, based on these results the use of therapeutic anticoagulation during IVC filter dwell should not be dictated by the presence of an IVC filter alone but rather by the presence of a related thrombosis event.

Brazilian Academy of Neurology practice guidelines for stroke rehabilitation: part I

The Guidelines for Stroke Rehabilitation are the result of a joint effort by the Scientific Department of Neurological Rehabilitation of the Brazilian Academy of Neurology aiming to guide professionals involved in the rehabilitation process to reduce functional disability and increase individual autonomy. Members of the group participated in web discussion forums with predefined themes, followed by videoconference meetings in which issues were discussed, leading to a consensus. These guidelines, divided into two parts, focus on the implications of recent clinical trials, systematic reviews, and meta-analyses in stroke rehabilitation literature. The main objective was to guide physicians, physiotherapists, speech therapists, occupational therapists, nurses, nutritionists, and other professionals involved in post-stroke care. Recommendations and levels of evidence were adapted according to the currently available literature. Part I discusses topics on rehabilitation in the acute phase, as well as prevention and management of frequent conditions and comorbidities after stroke.

Bismuth Nanoparticle and Polyhydroxybutyrate Coatings Enhance the Radiopacity of Absorbable Inferior Vena Cava Filters for Fluoroscopy-Guided Placement and Longitudinal Computed Tomography Monitoring in Pigs

Inferior vena cava filters (IVCFs) constructed with poly-p-dioxanone (PPDO) are promising alternatives to metallic filters and their associated risks and complications. Incorporating high-Z nanoparticles (NPs) improves PPDO IVCFs' radiopacity without adversely affecting their safety or performance. However, increased radiopacity from these studies are insufficient for filter visualization during fluoroscopy-guided PPDO IVCF deployment. This study focuses on the use of bismuth nanoparticles (BiNPs) as radiopacifiers to render sufficient signal intensity for the fluoroscopy-guided deployment and long-term CT monitoring of PPDO IVCFs. The use of polyhydroxybutyate (PHB) as an additional layer to increase the surface adsorption of NPs resulted in a 2-fold increase in BiNP coating (BiNP-PPDO IVCFs, 3.8%; BiNP-PPDO + PHB IVCFs, 6.2%), enabling complete filter visualization during fluoroscopy-guided IVCF deployment and, 1 week later, clot deployment. The biocompatibility, clot-trapping efficacy, and mechanical strength of the control PPDO (load-at-break, 6.23 ± 0.13 kg), BiNP-PPDO (6.10 ± 0.09 kg), and BiNP-PPDO + PHB (6.15 ± 0.13 kg) IVCFs did not differ significantly over a 12-week monitoring period in pigs. These results indicate that BiNP-PPDO + PHB can increase the radiodensity of a novel absorbable IVCF without compromising device strength. Visualizing the device under conventional radiographic imaging is key to allow safe and effective clinical translation of the device.

Long-Term Outcomes in Patients with Not-Retrieval Inferior Vena Cava Filter Under Anticoagulation

Since permanent inferior vena cava (IVC) filters increase deep vein thrombosis (DVT), filter retrieval should be performed as possible. Despite the guideline recommendation, IVC filters are not always retrieved in clinical practice. To date, many patients with not-retrieval IVC filters have been prescribed anticoagulant therapy, but the long-term prognosis, including venous thromboembolism (VTE) and bleeding events, remains unknown. In this study, 195 patients who underwent IVC filter implantation between 2006 and 2017 at 3 institutions in Niigata City have been investigated about their deaths, VTE recurrence, and bleeding events. After peaking 2009, the number of IVC filter implantation gradually decreased. During observational period, there were 158 patients with not-retrieval IVC filters (the overall retrieval rate of 19.0%). The not-retrieval group included significantly older and more patients with cancer compared to the retrieval group. Anticoagulation therapy was continued in 88% of the not-retrieval group. During a mean follow-up of 5.0 years, 6 symptomatic DVT events associated with inadequate control of anticoagulation and 13 bleeding events were observed. A total of 52 patients died and only the presence of cancer was prognostic risk factor. Although long-term anticoagulation therapy may be associated with bleeding events, there were few recurrent VTE under optimal anticoagulation. It is anticipated that even if the IVC filter cannot be retrieved, appropriate anticoagulation is useful for prevention of DVT recurrence despite the risk of bleeding.

The Good, Bad, and Ugly of Inferior Vena Cava (IVC) Filters: Anesthetic Management for IVC Filter Retrieval in the Setting of Filter Thrombosis

We describe a case of a 58-year-old man presenting to the interventional radiology (IR) suite for inferior vena cava (IVC) filter retrieval and potential intravascular iliocaval stent reconstruction in the setting of anticoagulation and uncontrolled hypertension. This patient had recently undergone iliocaval thrombectomy with IVC venoplasty four weeks prior to presentation. Induction of anesthesia and endotracheal intubation occurred without complication. The patient received two large-bore intravenous (IV) catheters and a radial artery catheter for hemodynamic monitoring. Blood was cross-matched and kept in the IR suite, anticipating bleeding from a potential injury to the IVC during filter retrieval. Fortunately, the thrombosed filter was removed without complication. This case illustrates the importance of in-depth anesthetic planning for so-called “benign” surgical procedures and highlights the challenges faced in non-operating room locations for anesthesiologists.

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.

Prophylaxis and management of venous thromboembolism during pregnancy and postpartum period

Introduction. Venous thromboembolism (VTE) is one of the lead causes for maternal mortality and morbidity during pregnancy in the majority of developed countries. The incidence rate of VTE per pregnancy-year increases during pregnancy and postpartum period about by 4-fold and at least 14-fold, respectively.

Aim: to analyze and summarize current view on risk factors of thrombotic events during gestation and to discuss recent guidelines for the management of venous thromboembolic complications during pregnancy and postpartum, by taking into account a balance between risks and benefits of using anticoagulants.

Materials and Methods. The literature search covering the last 10 years was carried out in the electronic scientific databases RSCI, PubMed/MEDLINE, and Embase. While formulating a search strategy for evidence-based information, the PICO method (P = Patient; I = Intervention; C = Comparison; O = Outcome) and the key terms “venous thromboembolism” and “pregnancy” were used.

Results. Risk factors were found to include a personal history of VTE, verified inherited or acquired thrombophilia, a family history of VTE and general medical conditions, such as immobilization, overweight, varicose veins, some hematological diseases and autoimmune disorders. VTE is considered being potentially preventable upon prophylactic administration of anticoagulants, but no high confidence randomized clinical trials comparing diverse strategies of thromboprophylaxis in pregnant women have been proposed so far. Because heparins do not cross the placenta, weight-adjusted therapeutic-dose low molecular weight heparins (LMWH) represent the anticoagulant treatment of choice for VTE during pregnancy. Once- and twice-daily dosing regimens are acceptable. However, no evidence suggesting benefits for measurement of factor Xa activities and consecutive LMWH dose adjustments to improve clinical outcomes are available. In case of uncomplicated pregnancy-related VTE, no routine administration of vitamin K antagonists, direct thrombin or factor Xa inhibitors, fondaparinux, or danaparoid is recommended. Lactating women may switch from applying LMWH to warfarin. Anticoagulation therapy should be continued for 6 weeks postpartum with total duration lasting at least for 3 months.

Conclusion. VTE is a challenging task in pregnant women expecting to apply a multi-faceted approach for its efficient solution by taking into account updated recommendations and personalized patient-oriented features.

Venous Thromboembolism for the Practicing Cardiologist

Venous thromboembolism (VTE), encompassing pulmonary embolism (PE) and deep vein thrombosis (DVT), is encountered commonly. Acute PE may present as a high-risk cardiovascular emergency, and acute DVT can cause acute and chronic vascular complications. The goal of this review is to ensure that cardiologists are comfortable managing VTE-including risk stratification, anticoagulation therapy, and familiarity with primary reperfusion therapy. Clinical assessment and determination of degree of right ventricular dysfunction are critical in initial risk stratification of PE and determination of parenteral versus oral anticoagulation therapy. Direct oral anticoagulants have emerged as preferred first-line oral anticoagulation strategy in VTE scenarios.

Pregnancy in women with an inferior vena cava filter: a tertiary center experience and overview of the literature

The risk of pregnancy in women with in situ vena cava filter is unknown and was evaluated in a cohort study and literature.

Only 20 pregnancies were identified; 1 published case with pre-existent filter perforation had uterine trauma and fetal loss.

Patients with an inferior vena cava (IVC) filter that remains in situ encounter a lifelong increased risk of deep vein thrombosis and IVC filter complications including fracture, perforation, and IVC filter thrombotic occlusion. Data on the safety of becoming pregnant with an in situ IVC filter are scarce. The objective was to evaluate the risk of complications of in situ IVC filters during pregnancy. We performed a retrospective cohort study of pregnant patients with an in situ IVC filter from a tertiary center between 2000 and 2020. We collected data on complications of IVC filters and pregnancy outcomes. Additionally, we performed a systematic literature search in MEDLINE, Embase, and gray literature. We identified 7 pregnancies in 4 patients with in situ IVC filters with a mean time since IVC filter insertion of 3 years (range, 1-8). No complications of IVC filter occurred during pregnancy. Review of literature yielded five studies including 13 pregnancies in 9 patients. In 1 pregnancy a pre-existent, until then asymptomatic, chronic perforation of the vena cava wall by the IVC filter caused major bleeding and uterine trauma with fetal loss. Overall, the complication rate was 5%. It seems safe to become pregnant with an indwelling IVC filter that is intact and does not show signs of perforation, but because of the low number of cases, no firm conclusions about safety of in situ IVC filters during pregnancy can be drawn. We suggest imaging before pregnancy to reveal asymptomatic IVC filter complications.

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.

Venous thromboembolism: Recent advancement and future perspective

Clinicians have been more and more often encountering patients with venous thromboembolism (VTE), including pulmonary embolism and deep vein thrombosis, leading to the increased importance of VTE in daily clinical practice. VTE is becoming a common issue in Asian countries including Japan. The management strategies of VTE have changed dramatically in the past decade including the introduction of direct oral anticoagulants (DOACs). In addition, there have been several landmark clinical trials assessing acute treatment strategies including thrombolysis and inferior vena cava (IVC) filter. The current VTE guidelines do not recommend the routine use of thrombolysis or IVC filters based on recent evidence; Nevertheless, the prevalence of thrombolysis and IVC filter use in Japan was strikingly high. The novel profiles of DOACs with rapid onset of action and potential benefit of a lower risk for bleeding compared with vitamin K antagonist could make home treatment feasible and is safer even with extended anticoagulation therapy. One of the most clinically relevant issues for VTE treatment is optimal duration of anticoagulation for the secondary prevention of VTE. Considering recent evidence, optimal duration of anticoagulation should be determined based on the risk for recurrence as well as the risk for bleeding in an individual patient. Despite the recent advances for VTE management, there are still a number of uncertain issues that challenge clinicians in daily clinical practice, such as cancer-associated VTE and minor VTE including subsegmental pulmonary embolism and distal deep vein thrombosis, warranting future research. Several clinical trials are now ongoing for these issues, globally as well as in Japan. The current review is aimed to overview the recent advances in VTE management, describe the current status including some domestic issues in Japan, and discuss the future perspective of VTE.

Antithrombotic Therapy for VTE Disease: Second Update of the CHEST Guideline and Expert Panel Report - Executive Summary

BACKGROUND

This is the second update to the 9^th edition of these guidelines. We provide recommendations on 17 PICO (Patients, Interventions, Comparators, Outcomes) questions, four of which have not been addressed previously.

METHODS

We generate strong and weak recommendations based on high, moderate, and low-certainty evidence, using GRADE methodology.

RESULTS

The panel generated 29 guidance statements, 13 of which are graded as strong recommendations, covering aspects of antithrombotic management of venous thromboembolism from initial management through secondary prevention and risk reduction of post-thrombotic syndrome. Four new guidance statements are added that did not appear in the 9^th edition (2012) or first update (2016). Eight statements have been substantially modified from the first update.

CONCLUSION

New evidence has emerged since 2016 which further informs the standard of care for patients with venous thromboembolism. Substantial uncertainty remains regarding important management questions, particularly in limited disease and special patient populations.

How I treat anticoagulant-refractory thrombotic antiphospholipid syndrome

The standard treatment of thrombotic antiphospholipid syndrome (APS) is lifelong oral anticoagulation with a vitamin K antagonist (VKA), generally warfarin. A minority of patients with APS rethrombose despite seemingly adequate anticoagulation. These patients are deemed anticoagulant refractory. The management of anticoagulant-refractory APS is largely empirical and extrapolated from other clinically similar situations. Further options include increased VKA anticoagulation intensity or alternative antithrombotic strategies, including low-molecular-weight heparin, fondaparinux, the addition of antiplatelet therapy, and consideration of vascular options. Patients with anticoagulant-refractory thrombotic APS may have APS-associated thrombocytopenia, which necessitates balancing the risk of recurrent thrombosis vs bleeding to achieve adequate anticoagulation. The multiple mechanisms involved in the generation of the thrombotic phenotype in APS suggest that anticoagulation alone may not control thrombosis. Thus, other modalities, including adjunctive treatment (hydroxychloroquine, statins, and vitamin D) for APS-related thrombosis, merit consideration, as do immunomodulatory therapy and complement inhibition. Patients with APS may have coexistent systemic lupus erythematosus, which adds to the complexity of managing their thromboembolic disease. However, with attention to detail and judicious application of the limited data, it is possible to minimize the morbidity resulting from anticoagulant-refractory thrombotic APS. Multicenter studies are required to guide the sequence of interventions and their comparative efficacy in patients with anticoagulant-refractory thrombotic APS.

Preferential central venous catheter access with concurrent IVC filter use

In our aging population, there is an increased incidence of concurrent IVC filter and central venous catheter use. One of the risks of concurrent use is filter embolization, which almost always occurs due to the J-tipped guidewire. In this case, we describe the successful placement of a central venous catheter in the femoral vein in a patient with an IVC filter. Some guidelines exist concerning CVC placement in patients with IVC filters, and this case highlights the benefits of placing a CVC in the femoral vein. While little research exists regarding higher rates of IVC filter embolization in internal jugular and subclavian vein access sites, we hypothesize it is due to the conical shape of IVC filters.

An Uncommon Cause of Shock: Acute Thrombosis of the Inferior Vena Cava

BACKGROUND

Obstructive shock is an uncommon presentation to the emergency department (ED) and is most often caused by an acute pulmonary embolism. A very rare cause of obstructive shock is extensive deep venous thrombosis, otherwise known as phlegmasia cerulea dolens. We present a case of obstructive shock caused by placement of an inferior vena cava filter complicated by acute occlusion with extensive deep venous thrombosis.

CASE REPORT

A 57-year-old man presented to the ED with hypotension, lethargy, and chronic leg pain. The day prior he had an inferior vena cava filter placed and was taken off his anticoagulation approximately 1 week prior. Massive pulmonary embolism was excluded as the cause based on point-of-care ultrasound showing absence of right heart strain. His initial resuscitation and evaluation did not determine the cause of his shock and he was empirically treated for sepsis. After adequate blood pressure was achieved with norepinephrine, his lower extremities were noted to be cyanotic and an ultrasound revealed the diagnosis of phlegmasia cerulea dolens. The shock state resolved after catheter-directed thrombolysis. Why Should an Emergency Physician Be Aware of This? Although unique, this case highlights an alternative cause of obstructive shock and informs emergency physicians about a potential deadly complication of a common procedure.

Effect of inferior vena cava filters on pulmonary embolism-related mortality and major complications: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

Inferior vena cava (IVC) filters are often used. However, no clear consensus has been reached regarding the benefits and risks from randomized, controlled trials. Therefore, we investigated benefits and risks of IVC filter use.

METHODS

The PubMed and Cochrane Library databases were searched from inception to October 31, 2019 to identify randomized, controlled trials for inclusion in our meta-analysis. The primary outcome was mortality related to pulmonary embolism (PE). The secondary outcomes were overall mortality, PE, deep vein thrombosis, and major bleeding. Risk ratios were pooled using the Mantel-Haenszel method with the fixed effects model for low heterogeneity. Otherwise, the random effects model was used. Risk differences were considered candidates of effect size if some of the data could not be pooled in the calculations.

RESULTS

Seven articles with 1274 patients were included. We found no significant difference in mortality related to PE between the IVC filter and control groups within 3 months (risk difference, -0.01; 95% confidence interval, -0.03 to 0.00; P = .11) nor during the entire follow-up period with low heterogeneity (I² = 0%). The new occurrence of PE within 3 months and during the whole follow-up period was lower in the IVC filter group than in the control group (0.81% vs 5.98%; risk ratio, 0.17; 95% CI, 0.04-0.65; P = .01; and 3.2% vs 7.79%; risk ratio, 0.42; 95% CI, 0.25-0.71; P = .001, respectively). No significant differences were found in the rates of the new occurrence of deep vein thrombosis, major bleeding, and mortality during the whole follow-up period between the two groups (P > .05).

CONCLUSIONS

We found insufficient evidence to conclude that the use of IVC filters can reduce mortality. However, the use of IVC filters decreased the new occurrence of PE without increasing deep vein thrombosis or major bleeding.

Percutaneous endovenous intervention without vena cava filter for acute proximal deep vein thrombosis secondary to iliac vein compression syndrome: preliminary outcomes

The aim is to report the preliminary outcomes of percutaneous endovenous intervention (PEVI) for acute proximal deep vein thrombosis (DVT) secondary to iliac vein compression syndrome (IVCS) without inferior vena cava filter (IVCF) placement. Acute DVT patients who underwent PEVI without IVCF were analyzed retrospectively. PEVI consisted of catheter-directed thrombolysis, manual aspiration thrombectomy, balloon angioplasty and stenting. CT was used to evaluate the left common iliac vein (LCIV). Sixty-two consecutive patients (17 men and 45 women, mean age, 59.4 ± 15.2 years) were enrolled. The compression percentage of the LCIV ranged from 51.7% to 95.2% (median 83.2%). Iliac DVT was present in 7 patients; iliofemoral, in 30 patients; and iliofemoropopliteal, in 25 patients. Complete technical success and clinical improvement were obtained in all subjects without the occurrence of symptomatic pulmonary embolism (PE). Five patients experienced recurrent thrombosis. The primary patency rates at 12 and 24 months were 93.8% and 91.4%, respectively, which remained stable at 36, 48 and 60 months. The secondary patency rates at 12 and 24 months were 95.7% and 93.3%, respectively, and there was no change at 60 months. Although limited, our preliminary results suggested that PEVI without IVCF placement seemed to be safe and effective for acute proximal DVT secondary to IVCS without inferior vena cava thrombosis or symptomatic PE.

Feasibility and optimization of ultra-short echo time MRI for improved imaging of IVC-filters at 3.0 T

PURPOSE

To determine the feasibility of ultra-short echo time (UTE) MRA for assessment of inferior vena cava (IVC) filters and evaluate the impact of different imaging protocols at 3.0 T, using conventional Cartesian MRA (cMRA) as the reference standard.

METHODS

Patients with IVC-filters were recruited for this prospective IRB-approved, HIPAA-compliant study. Subjects underwent contrast-enhanced breath-held and a free-breathing 3D radial acquisition UTE-MRA (bhUTE, fbUTE) at three different flip angles (FA: 10°, 15°, 20°) to optimize T1-weighted image quality. Two radiologists performed a direct comparison consensus reading to assess the optimal FA. Image quality (IQ) of both UTE techniques at the best FA was rated independently on a 4-point Likert scale (0 = non-diagnostic, 3 = excellent) and compared to 3D T1-weighted breath-held cMRA.

RESULTS

Nine subjects were recruited. Low FAs of 10° were rated best for both UTE techniques. fbUTE was excellent (3, IQR: 2; 3) and significantly better for IVC-filter depiction than cMRA (2, IQR: 0.75; 2, p = 0.001) and bhUTE (1.5, IQR: 0.75; 2, p < 0.001). Both UTE techniques showed significantly less filter-related artifacts (fbUTE: 28%, bhUTE: 33%) than cMRA (89%, p = 0.001 and p = 0.002, respectively). However, IQ of bhUTE was generally degraded due to high image noise and low image contrast. IQ of the IVC venogram was best with cMRA. Clinically relevant signal voids were only observed with the cage-shaped OptEase filter.

CONCLUSION

UTE-MRA is feasible at 3.0 T for the assessment of IVC-filters, particularly using a free-breathing protocol. Larger studies are needed to investigate the clinical utility of free-breathing UTE-MRA for assessment of IVC-filter-related complications.

Venous thromboembolism in orthopaedic oncology

AIMS

Malignancy and surgery are risk factors for venous thromboembolism (VTE). We undertook a systematic review of the literature concerning the prophylactic management of VTE in orthopaedic oncology patients.

METHODS

MEDLINE (PubMed), EMBASE (Ovid), Cochrane, and CINAHL databases were searched focusing on VTE, deep vein thrombosis (DVT), pulmonary embolism (PE), bleeding, or wound complication rates.

RESULTS

In all, 17 studies published from 1998 to 2018 met the inclusion criteria for the systematic review. The mean incidence of all VTE events in orthopaedic oncology patients was 10.7% (1.1% to 27.7%). The rate of PE was 2.4% (0.1% to 10.6%) while the rate of lethal PE was 0.6% (0.0% to 4.3%). The overall rate of DVT was 8.8% (1.1% to 22.3%) and the rate of symptomatic DVT was 2.9% (0.0% to 6.2%). From the studies that screened all patients prior to hospital discharge, the rate of asymptomatic DVT was 10.9% (2.0% to 20.2%). The most common risk factors identified for VTE were endoprosthetic replacements, hip and pelvic resections, presence of metastases, surgical procedures taking longer than three hours, and patients having chemotherapy. Mean incidence of VTE with and without chemical prophylaxis was 7.9% (1.1% to 21.8%) and 8.7% (2.0% to 23.4%; p = 0.11), respectively. No difference in the incidence of bleeding or wound complications between prophylaxis groups was reported.

CONCLUSION

Current evidence is limited to guide clinicians. It is our consensus opinion, based upon logic and deduction, that all patients be considered for both mechanical and chemical VTE prophylaxis, particularly in high-risk patients (pelvic or hip resections, prosthetic reconstruction, malignant diagnosis, presence of metastases, or surgical procedures longer than three hours). Additionally, the surgeon must determine, in each patient, if the risk of haemorrhage outweighs the risk of VTE. No individual pharmacological agent has been identified as being superior in the prevention of VTE events. Cite this article: Bone Joint J 2020;102-B(12)1743:-1751.

Symptomatic duodenal perforation by a Bird's Nest vena cava filter

This case describes a patient with a permanent Bird's Nest inferior vena cava filter in the setting of spinal cord injury and paraplegia who presented with epigastric pain resulting from duodenal perforation of his filter. After confirming that the patient was stable hemodynamically with normal laboratory values, he underwent open exploration with trimming of the extraluminal struts and wires, leaving the intact filter in place, with resolution of his pain. Although percutaneous removal of inferior vena cava filters is preferred for retrievable filters, this case demonstrates the safety and efficacy of open surgical management for permanent filters, not designed for retrieval.

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.

First-in-Human Study with Eight Patients Using an Absorbable Vena Cava Filter for the Prevention of Pulmonary Embolism

PURPOSE

To prospectively evaluate the initial human experience with an absorbable vena cava filter designed for transient protection from pulmonary embolism (PE).

MATERIALS AND METHODS

This was a prospective, single-arm, first-in-human study of 8 patients with elevated risk of venous thromboembolism (VTE). Seven absorbable IVC filters (made of polydioxanone that breaks down into H₂O and CO₂ in 6 mo) were placed prophylactically before orthopedic (n = 5) and gynecologic (n = 2) surgeries, and 1 was placed in a case of deep vein thrombosis. Subjects underwent CT cavography and abdominal radiography before and 5, 11, and 36 weeks after filter placement to assess filter migration, embolization, perforation, and caval thrombosis and/or stenosis. Potential PE was assessed immediately before and 5 weeks after filter placement by pulmonary CT angiography.

RESULTS

No symptomatic PE was reported throughout the study or detected at the planned 5-week follow-up. No filter migration was detected based on the fixed location of the radiopaque markers (attached to the stent section of the filter) relative to the vertebral bodies. No filter embolization or caval perforation was detected, and no caval stenosis was observed. Throughout the study, no filter-related adverse events were reported.

CONCLUSIONS

Implantation of an absorbable vena cava filter in a limited number of human subjects resulted in 100% clinical success. One planned deployment was aborted as a result of stenotic pelvic veins, resulting in 89% technical success. No PE or filter-related adverse events were observed.

Management of anticoagulant-refractory thrombotic antiphospholipid syndrome

Lifelong anticoagulation with warfarin or alternative vitamin K antagonist is the standard anticoagulant treatment for thrombotic antiphospholipid syndrome. Anticoagulant-refractory thrombotic antiphospholipid syndrome can be broadly defined as breakthrough thrombosis while on standard oral anticoagulation treatment and its management is a major challenge given the serious nature of the thrombotic disease observed, which has become refractory to oral anticoagulation. The factors (genetic and cellular) that cause anticoagulant-refractory thrombotic antiphospholipid syndrome are now better understood. However, efforts to use this greater understanding have not yet transformed the capacity to treat it successfully in many patients. In this Viewpoint, we review the factors that are likely to be contributing to the cause of this syndrome and consider how they might be modified or inhibited. We also discuss management, including general strategies to minimise thrombotic risk, intensification of anticoagulation, addition of an antiplatelet agent, adjunctive treatment for thrombosis, immunomodulatory therapy, complement inhibition, vascular options, and future potential therapeutic targets.