Society of Interventional Radiology Clinical Practice Guideline for Inferior Vena Cava Filters in the Treatment of Patients with Venous Thromboembolic Disease: Developed in collaboration with the American College of Cardiology, American College of Chest Physicians, American College of Surgeons Committee on Trauma, American Heart Association, Society for Vascular Surgery, and Society for Vascular Medicine.

PURPOSE: To provide evidence-based recommendations on the use of inferior vena cava (IVC) filters in the treatment of patients with or at substantial risk of venous thromboembolic disease. MATERIALS AND METHODS: A multidisciplinary expert panel developed key questions to address in the guideline, and a systematic review of the literature was conducted. Evidence was graded based on a standard methodology, which was used to inform the development of recommendations. RESULTS: The systematic review identified a total of 34 studies that provided the evidence base for the guideline. The expert panel agreed on 18 recommendations. CONCLUSIONS: Although the evidence on the use of IVC filters in patients with or at risk of venous thromboembolic disease varies in strength and quality, the panel provides recommendations for the use of IVC filters in a variety of clinical scenarios. Additional research is needed to optimize care for this patient population.

Interventional Radiology Therapy: Inferior Vena Cava Filter and Catheter-based Therapies.

Endovascular management of pulmonary embolism can be divided into therapeutic and prophylactic treatments. Prophylactic treatment includes inferior vena cava filter placement, whereas endovascular therapeutic interventions include an array of catheter-directed therapies. The indications for both modalities have evolved over the last decade as new evidence has become available.

Perioperative mortality secondary to a pulmonary embolism during a surgical implantation of the Endo-Exo-Prosthesis: a case report.

We report on a 53-year-old female patient who suffered a perioperative death secondary to a pulmonary embolism (PE) during an implantation of Endo-Exo-Prosthesis. This is a retrospective review of medical case for a patient who had a previous above-the-knee amputation secondary to a failed previous arthroplasty surgery. Our planned surgery was a stage 1 implantation of an Endo-Exo-Prosthesis, and it was performed under general anaesthesia. After 25 min from starting the surgical procedure, the patient sustained a cardiac arrest, and despite an active cardiopulmonary resuscitation for 50 min, the patient did not recover, the ventilator machine was stopped later on, and the patient was declared deceased at that stage. Fatal intraoperative PE is a rare but significant complication during orthopaedic procedures. There are few reports of similar events but include mainly trauma patients with fractured neck of femur. Endo-Exo-Prosthesis is a relatively newly evolved procedure in a unique group of patients. To our knowledge, this is the first case report of such complication during Endo-Exo-Prosthesis implantation. Patient and surgeon should be aware of it, and additional preventive measures like preoperative scoring systems and in special cases using inferior vena cava filter should be considered in patients with high risk of developing venous thromboembolism.

Removal of retrievable inferior vena cava filters before discharge: Is it associated with increased incidence of pulmonary embolism?

BACKGROUND: Severely injured trauma patients are at high risk of developing deep venous thrombosis and pulmonary emboli (PE), and may have contraindications to prophylactic or therapeutic anticoagulation. Retrievable inferior vena cava filters (rIVCFs) are used to act as a mechanical obstruction to prevent PE in high risk populations and those with deep venous thrombosis who cannot be anticoagulated. The removal rate of rIVCFs is variable in trauma centers, including our previous published rate of 50% to 89%/year. Indwelling filters carry a risk of significant morbidity and the success of retrieval decreases as the dwell time increases. We hypothesized that once patients could receive appropriate prophylactic or therapeutic anticoagulation, rIVCF could be removed before hospital discharge without impact on occurrence or recurrence of PE. METHODS: All trauma patients with rIVCF placed and removed between January 2006 and August 2018 were reviewed. We collected data from record review from admission to 6 months postfilter removal, including demographics, filter indication, filter type, dwell time, placement and removal complications, antithrombosis medications, location of venous thromboembolism, complications, and discharge disposition. Exposure of interest was timing of filter removal: before (BEF) or after hospital discharge (AFT). The outcome of interest was whether the patient had a documented PE within 6 months of filter removal. RESULTS: A total of 281 rIVCFs were placed, 218 were eligible for removal, 72.4% (158/218) were retrieved with 63% (100/158) removed before discharge. Mean filter duration was 26 days and 103 days for the before and after groups, respectively. No differences (p > 0.05) were noted in the distribution of demographic and clinical factors except for filter indication (venous thromboembolism indication, 95% in AFT vs. 74% in BEF, p = 0.0043). Postremoval PE rates were 0% BEF and 1% AFT (Fisher's exact test, p = 1.000). CONCLUSION: Our results suggest that removal of rIVCFs before discharge once patients are appropriately anticoagulated is a safe strategy to improve retrieval rates. LEVEL OF EVIDENCE: Therapeutic, level V.

Vena cava filters in patients presenting with major bleeding during anticoagulation for venous thromboembolism.

The association between inferior vena cava filter (IVC) use and outcome in patients presenting with major bleeding during anticoagulation for venous thromboembolism (VTE) has not been thoroughly investigated. We used the RIETE registry to compare the 30-day outcomes (death, major re-bleeding or VTE recurrences) in VTE patients who bled during the first 3 months of therapy, regarding the insertion of an IVC filter. A propensity score matched (PSM) analysis was performed to adjust for potential confounders. From January 2001 to September 2016, 1065 VTE patients had major bleeding during the first 3 months of anticoagulation (gastrointestinal 370; intracranial 124). Of these, 122 patients (11%) received an IVC filter. Patients receiving a filter restarted anticoagulation later (median, 4 vs. 2 days) and at lower doses (95 ± 52 IU/kg/day vs. 104 ± 55 of low-molecular-weight heparin) than those not receiving a filter. During the first 30 days after bleeding (after excluding 246 patients who died within the first 24 h), 283 patients (27%) died, 63 (5.9%) had non-fatal re-bleeding and 19 (1.8%) had recurrent pulmonary embolism (PE). In PSM analysis, patients receiving an IVC filter (n = 122) had a lower risk for all-cause death (HR 0.49; 95% CI 0.31-0.77) or fatal bleeding (HR 0.16; 95% CI 0.07-0.49) and a similar risk for re-bleeding (HR 0.55; 95% CI 0.23-1.40) or PE recurrences (HR 1.57; 95% CI 0.38-6.36) than those not receiving a filter (n = 429). In VTE patients experiencing major bleeding during the first 3 months, use of an IVC filter was associated with reduced mortality rates.Clinical Trial Registration NCT02832245.

Prevention of Deep Venous Thromboembolism.

The nature of many combat wounds puts patients at a high risk of developing deep venous thrombosis (DVT) and pulmonary embolism (PE), which fall under the broader disease category of venous thromboembolism (VTE). In addition to the hypercoagulable state induced by trauma, massive injuries to the extremities, prolonged immobility, and long fixed wing transport times to higher echelons of care are unique risk factors for venous thromboembolism in the combat-injured patient. These risk factors mandate aggressive prophylaxis for DVT and PE that can effectively be achieved by the use of lower extremity sequential compression devices and low dose unfractionated heparin or low molecular weight heparin. In addition, inferior vena cava filters are often used for PE prophylaxis when chemical DVT prophylaxis fails or is contraindicated. The following Department of Defense (DoD) Joint Trauma System (JTS) Clinical Practice Guideline (CPG) discusses the current recommendations for the prevention of DVT and PE including the use of inferior vena cava filters (IVCFs).

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.

Hospitalization metrics associated with hospital-level variation in inferior vena cava filter utilization for patients with venous thromboembolism in the United States: Implications for quality of care.

Variation in the use of inferior vena cava filters (IVCFs) across hospitals has been observed, suggesting differences in quality of care. Hospitalization metrics associated with venous thromboembolism (VTE) patients have not been compared based on IVCF utilization rates using a national sample. We conducted a descriptive retrospective study using the Nationwide Readmissions Database (NRD) to delineate the variability of hospitalization metrics across the hospital quartiles of IVCF utilization for VTE patients. The NRD included all-payer administrative inpatient records drawn from 22 states. Adult (≥ 18 years) patients with VTE hospitalizations with or without IVCF were identified from January 1, 2013 through December 31, 2014 and hospitals were divided into quartiles based on the IVCF utilization rate as a proportion of VTE patients. Primary outcome measures were observed rates of in-hospital mortality, 30-day all-cause readmissions and VTE-related readmissions, cost, and length of stay. Patient case-mix characteristics and hospital-level factors by hospital quartiles of IVCF utilization rates, were compared. Overall, 12.29% of VTE patients had IVCF placement, with IVCF utilization ranging from 0% to 46.84%. The highest quartile had fewer pulmonary embolism patients relative to deep vein thrombosis patients, and older patient ages were present in higher quartiles. The highest quartile of hospitals placing IVCFs were more often private, for-profit, and non-teaching. Patient and hospital characteristics and hospitalization metrics varied by IVCF utilization rates, but hospitalization outcomes for non-IVCF patients varied most between quartiles. Future work investigating the implications of IVCF utilization rates as a measure of quality of care for VTE patients is needed.

European guidelines on perioperative venous thromboembolism prophylaxis: Inferior vena cava filters.

: The indications for the use of an inferior vena cava filter (IVCF) in the context of deep venous thrombosis to prevent pulmonary embolism remain controversial. Despite wide use in clinical practice, great variation exists in national and international guidelines in regard to the indications. In addition, clinical practice is based on poor-quality data from trauma and bariatric surgery with a high incidence of complications. It is often difficult to assess their efficacy and lack of filter retrieval appears to be a substantial issue compared with a potential benefit by insertion of these devices. Complications usually refer to increased risk of deep venous thrombosis, filter perforation, filter penetration, filter migration, inferior vena cava occlusion and subsequently failure in pulmonary embolism prevention. Evidence from low-quality studies or registries, with small numbers of patients and conflicting findings, does not allow for a strong recommendation for or against the use of IVCFs. IVCFs should only be considered in cases of very high risk of pulmonary embolism and in perioperative situations at very high risk of bleeding, resulting in a prolonged contra-indication to pharmacological prophylaxis.

Retrospective analysis of outcomes following inferior vena cava (IVC) filter placement in a managed care population.

The role of inferior vena cava filter (IVC) filters for prevention of pulmonary embolism (PE) is controversial. This study evaluated outcomes of IVC filter placement in a managed care population. This retrospective cohort study evaluated data for individuals with Humana healthcare coverage 2013-2014. The study population included 435 recipients of prophylactic IVC filters, 4376 recipients of therapeutic filters, and two control groups, each matched to filter recipients. Patients were followed for up to 2 years. Post-index anticoagulant use, mortality, filter removal, device-related complications, and all-cause utilization. Adjusted regression analyses showed a positive association between filter placement and anticoagulant use at 3 months: odds ratio (ORs) 3.403 (95% CI 1.912-6.059), prophylactic; OR, 1.356 (95% CI 1.164-1.58), therapeutic. Filters were removed in 15.67% of prophylactic and 5.69% of therapeutic filter cases. Complication rates were higher with prophylactic procedures than with therapeutic procedures and typically exceeded 2% in the prophylactic group. Each form of filter placement was associated with increases in all-cause hospitalization (regression coefficient 0.295 [95% CI 0.093-0.498], prophylactic; 0.673 [95% CI 0.547-0.798], therapeutic) and readmissions (OR 2.444 [95% CI 1.298-4.602], prophylactic; 2.074 [95% CI 1.644-2.616], therapeutic). IVC filter placement in this managed care population was associated with increased use of anticoagulants and greater healthcare utilization compared to controls, low rates of retrieval, and notable rates of device-related complications, with effects especially pronounced in assessments of prophylactic filters. These findings underscore the need for appropriate use of IVC filters.

A resolved two-way coupled CFD/6-DOF approach for predicting embolus transport and the embolus-trapping efficiency of IVC filters.

Inferior vena cava (IVC) filters are medical devices designed to provide a mechanical barrier to the passage of emboli from the deep veins of the legs to the heart and lungs. Despite decades of development and clinical use, IVC filters still fail to prevent the passage of all hazardous emboli. The objective of this study is to (1) develop a resolved two-way computational model of embolus transport, (2) provide verification and validation evidence for the model, and (3) demonstrate the ability of the model to predict the embolus-trapping efficiency of an IVC filter. Our model couples computational fluid dynamics simulations of blood flow to six-degree-of-freedom simulations of embolus transport and resolves the interactions between rigid, spherical emboli and the blood flow using an immersed boundary method. Following model development and numerical verification and validation of the computational approach against benchmark data from the literature, embolus transport simulations are performed in an idealized IVC geometry. Centered and tilted filter orientations are considered using a nonlinear finite element-based virtual filter placement procedure. A total of 2048 coupled CFD/6-DOF simulations are performed to predict the embolus-trapping statistics of the filter. The simulations predict that the embolus-trapping efficiency of the IVC filter increases with increasing embolus diameter and increasing embolus-to-blood density ratio. Tilted filter placement is found to decrease the embolus-trapping efficiency compared with centered filter placement. Multiple embolus-trapping locations are predicted for the IVC filter, and the trapping locations are predicted to shift upstream and toward the vessel wall with increasing embolus diameter. Simulations of the injection of successive emboli into the IVC are also performed and reveal that the embolus-trapping efficiency decreases with increasing thrombus load in the IVC filter. In future work, the computational tool could be used to investigate IVC filter design improvements, the effect of patient anatomy on embolus transport and IVC filter embolus-trapping efficiency, and, with further development and validation, optimal filter selection and placement on a patient-specific basis.

Impact of Physician Education and a Dedicated Inferior Vena Cava Filter Tracking System on Inferior Vena Cava Filter Use and Retrieval Rates Across a Large US Health Care Region.

PURPOSE: To evaluate the effects of physician familiarity with current evidence and guidelines on inferior vena cava (IVC) filter use and the availability of IVC filter tracking infrastructure on retrieval rates. MATERIALS AND METHODS: Fourteen continuing medical education-approved in-hospital grand rounds covering evidence-based review of the literature on IVC filter efficacy, patient-centered outcomes, guidelines for IVC filter indications, and complications were performed across a large United States (US) health care region serving more than 3.5 million members. A computer-based IVC filter tracking system was deployed simultaneously. IVC filter use, rates of attempted retrieval, and fulfillment of guidelines for IVC filter indications were retrospectively evaluated at each facility for 12 months before intervention (n = 427) and for 12 months after intervention (n = 347). RESULTS: After education, IVC filter use decreased 18.7%, with a member enrollment-adjusted decrease of 22.2%, despite an increasing IVC filter use trend for 4 years. Reduction in IVC filter use at each facility strongly correlated with physician attendance at grand rounds (r = -0.69; P = .007). Rates of attempted retrieval increased from 38.9% to 54.0% (P = .0006), with similar rates of successful retrieval (82.3% before education and 85.8% after education on first attempt). Improvement in IVC filter retrieval attempts correlated with physician attendance at grand rounds (r = 0.51; P = .051). IVC filter dwell times at first retrieval attempt were similar (10.2 wk before and 10.8 wk after). CONCLUSIONS: Physician education dramatically reduced IVC filter use across a large US health care region, and represents a learning opportunity for physicians who request and place them. Education and a novel tracking system improved rates of retrieval for IVC filter devices.

Improving inferior vena cava filter retrieval rates with the define, measure, analyze, improve, control methodology.

PURPOSE: To design a sustainable process to improve optional inferior vena cava (IVC) filter retrieval rates based on the Define, Measure, Analyze, Improve, Control (DMAIC) methodology of the Six Sigma process improvement paradigm. MATERIALS AND METHODS: DMAIC, an acronym for Define, Measure, Analyze, Improve, and Control, was employed to design and implement a quality improvement project to increase IVC filter retrieval rates at a tertiary academic hospital. Retrievable IVC filters were placed in 139 patients over a 2-year period. The baseline IVC filter retrieval rate (n = 51) was reviewed through a retrospective analysis, and two strategies were devised to improve the filter retrieval rate: (a) mailing of letters to clinicians and patients for patients who had filters placed within 8 months of implementation of the project (n = 43) and (b) a prospective automated scheduling of a clinic visit at 4 weeks after filter placement for all new patients (n = 45). The effectiveness of these strategies was assessed by measuring the filter retrieval rates and estimated increase in revenue to interventional radiology. RESULTS: IVC filter retrieval rates increased from a baseline of 8% to 40% with the mailing of letters and to 52% with the automated scheduling of a clinic visit 4 weeks after IVC filter placement. The estimated revenue per 100 IVC filters placed increased from $2,249 to $10,518 with the mailing of letters and to $17,022 with the automated scheduling of a clinic visit. CONCLUSIONS: Using the DMAIC methodology, a simple and sustainable quality improvement intervention was devised that markedly improved IVC filter retrieval rates in eligible patients.

In vitro comparison of Günther Tulip and Celect filters: testing filtering efficiency and pressure drop.

In this study, the trapping ability of the Günther Tulip and Celect inferior vena cava filters was evaluated. Thrombus capture rates of the filters were tested in vitro in horizontal position with thrombus diameters of 3 and 6mm and tube diameter of 19mm. The filters were tested in centered and tilted positions. Sets of 30 clots were injected into the model and the same process was repeated 20 times for each different condition simulated. Pressure drop experienced along the system was also measured and the percentage of clots captured was recorded. The Günther Tulip filter showed superiority in all cases, trapping almost 100% of 6mm clots both in an eccentric and tilted position and trapping 81.7% of the 3mm clots in a centered position and 69.3% in a maximum tilted position. The efficiency of all filters tested decreased as the size of the embolus decreased and as the filter was tilted. The injection of 6 clots raised the pressure drop to 4.1mmHg, which is a reasonable value that does not cause the obstruction of blood flow through the system.

Optimizing the use of inferior vena cava filters in oncology patients: are all filters created equally?

Many studies have supported the efficacy of inferior vena cava filters (IVCF) in the setting of venous thromboembolic disease, particularly in oncologic patients who are at increased risk. The advent of retrievable IVCF designs has prompted dramatically expanded use for patients with widely accepted indications but also disproportionately so in patients with so-called extended indications. At the same time, an alarming increase in filter-related complications has been reported both in the literature and through regulatory agencies, leading to government agency-issued warnings. The synergistic effect of these two interconnected phenomena is explained through a careful review of the evolution of IVCF device design. Critical differences exist when comparing retrievable IVCF and permanent IVCF. IVCF utilization can be optimized by prospectively identifying which patients are best served by a specific IVCF device. Careful follow-up strategies are also needed to ensure that all IVCFs are removed as soon as they are no longer needed. Finally, adjunctive techniques for removing "difficult" filters help maximize the number of IVCF removed and minimize IVCF left implanted needlessly.

Inferior vena cava filters.

Venous thromboembolism is common. Most pulmonary emboli arise as thromboses in the deep veins of the lower extremities and may result in serious complications. Inferior vena cava filters (IVCF) are intended to prevent the passage of deep vein thrombosis to the pulmonary arteries. Accepted indications for IVCF placement include the presence of acute venous thromboembolism with inability to administer anticoagulation medication or failure of anticoagulation. Despite these clear indications, IVCF have been commonly placed in patients for primary prevention of pulmonary emboli in patients deemed to be at high risk, along with several other "soft" indications. As a result, IVCF use has been rising over the past 2 decades, especially given the retrievable nature of modern devices. Nonetheless, IVCF are not free of complications, which may occur during implantation and retrieval and while retained in the body. Despite this increase in use, the long-term efficacy remains unclear, and the management of patients with retained filters is often controversial. Finally, filter retrieval in eligible patients is relatively infrequent, suggesting that systems must be in place to improve appropriate filter use and to increase retrieval.