Guidelines on use of vena cava filters

Clinical Correlates of In-Hospital Mortality in Patients Undergoing Inferior Vena Cava Filter Placement for Acute Deep Vein Thrombosis

Background: It is reasonable to place an Inferior Vena Cava Filter (IVCF) when an acute deep vein thrombosis (DVT) of the lower limbs occurs in a patient with absolute contraindication to therapeutic anticoagulation. An additional potential reason for placing an IVCF is the need to stop therapeutic anticoagulation in a patient with acute DVT who must undergo urgent non-deferrable surgery. However, IVCFs are often used outside of such established indications and many authors argue about their actual utility, especially in terms of survival. In this retrospective study, we looked for clinical correlates of in-hospital mortality among patients who underwent IVCF placement, limiting our analysis to the cases for which a correct indication to IVCF placement existed. Methods: We retrospectively analyzed the electronic database of our University Hospital, searching for consecutive hospitalized patients who had acute DVT and underwent IVCF placement because of an established contraindication to therapeutic anticoagulation and/or because it was necessary to stop anticoagulation due to urgent surgery. The search covered the period between 1 January 2010 and 31 December 2020. Results: The search resulted in the identification of 168 individuals. An established contraindication to therapeutic anticoagulation was present in 116 patients (69.0%), while urgent non-deferrable surgery was the reason for IVCF placement in 52 patients (31.0%). A total of 24 patients (14.3%) died during the same hospital stay in which the IVCF was placed. Mortality rate was significantly higher in patients with a contraindication to anticoagulation than in patients who underwent IVCF placement because of urgent surgery (19.0% vs. 3.8%, OD 5.85 vs. 0.17). In-hospital mortality was also significantly higher among patients with chronic kidney disease and those who needed blood cell transfusion during hospitalization. Conclusions: This study provides novel information on clinical correlates of in-hospital mortality among patients with acute DVT who undergo IVCF. Prospective observational studies are needed to substantiate these findings.

Risk factors for inferior vena cava filter thrombosis in traumatic fracture patients with deep venous thrombosis of lower extremity: A single-center experience

OBJECTIVE

To explore the risk factors for inferior vena cava filter (IVCF) thrombus in orthopedic trauma patients who underwent filter placement with ongoing anticoagulation in clinical settings.

METHODS

We retrospectively analyzed clinical data from fracture patients with lower extremity acute deep vein thrombosis (DVT) implanted with an IVCF admitted to Tianjin Hospital from January 2017 to December 2019. Potential risk factors, such as gender, age, diabetes, hypertension, fracture sites, thrombus location, free-floating thrombus, filter type, Injury Severity Score (ISS), and postoperative D-dimer values, were analyzed by the Chi-square test, t-test, logistic regression, and receiver operating characteristic (ROC) curve analysis.

RESULTS

A total of 662 patients were included in our study, and filter-related thrombosis was present in 67 (10.1%) patients. No significant differences were observed in age, gender, hypertension, diabetes, fracture site, free-floating thrombus, filter type, indwelling time, and postoperative D-dimer level. Thrombus location and ISS were significantly different (p < 0.05). Popliteal DVT (P-DVT) (odds ratio [OR]: 2.130, p = 0.018) and ISS (OR: 1.135, p = 0.000) were associated with filter thrombus. Patients with P-DVT were prone to a small filter thrombus (OR: 3.231, p = 0.037). From the ROC curve analysis, the diagnostic value of ISS was 24.5 and 26.5 for patients with filter and massive filter thrombus, respectively.

CONCLUSION

Thrombus location and ISS were independent risk factors for filter thrombus in patients with traumatic fractures. P-DVT had a higher potential to result in a small filter thrombus and an ISS value >26.5, which was considered a significant massive filter thrombus predictor.

The use of pre-operative Inferior Vena Cava filters for thromboprophylaxis in ultra-high-risk patients undergoing total hip and knee arthroplasty: a systematic review and narrative analysis

PURPOSE

Patients undergoing total hip (THA) or knee (TKA) arthroplasty are at high risk of venous thromboembolism (VTE). As the number performed annually increases, the population at risk of fatal pulmonary embolism (PE) also grows. Ultra-high-risk arthroplasty patients (UHRAPs) include those with additional comorbidities, or a history of VTE, for many of whom routine prophylaxis will previously have failed. Pre-operative insertion of Inferior Vena Cava filters (IVCFs) has been recommended for thromboprophylaxis in UHRAPs, and this review was performed to establish their results.

METHODS

A systematic search of MEDLINE and Embase databases was performed for studies reporting the use of Inferior Vena Cava filters in hip and knee arthroplasty patients.

RESULTS

Ten studies met the inclusion criteria, containing 718 IVCFs in Orthopaedic patients, 343 of which were permanent (47.8%), 369 potentially retrievable (51.4%), 5 absorbable (0.6%) and one of unknown design (0.1%). Patient age averaged 64.7yrs (17-95) and 56% were female. Pre-operatively, 415 prophylactic IVCFs were inserted in 409 UHRAPs, undergoing a total of 438 total joint arthroplasties (TJA). There were 11 cases of PE in the entire series (1.5%) only one of which was fatal (0.01%), with four non-fatal PE in the UHRAP group (0.96%). Removal was attempted for 283 of the retrievable filters (76.7%) and was successful in 280 (98.9%).

CONCLUSION

The use of IVCFs eliminated fatal PE in UHRAPs, but larger, high-quality studies, with standardised reporting, are still required to determine their absolute indications for use, complication profile, efficacy and optimum design.

How I approach the prevention and treatment of thrombotic complications in hospitalized patients

This article uses case-based discussion to review prevention and management of thrombotic problems in hospitalized patients that involve a clinical hematologist. There is variation in the clinical hematologist's role in thrombosis practice throughout the world, and we discuss this where indicated. Hospital-associated venous thromboembolism (VTE), or hospital-associated thrombosis (HAT), is the term to cover VTE occurring during admission and for 90 days postdischarge and is a common patient safety problem. HATs are the most common cause of VTE accounting for 55% to 60% of all VTE, with an estimated 10 million occurring globally. VTE risk assessment alongside evidence-based thromboprophylaxis reduces this risk significantly. Many hospitalized patients, especially older patients, use direct oral anticoagulants (DOACs), mainly to prevent stroke in atrial fibrillation. DOACs require perioperative management and may need urgent reversal. Other complex interventions such as extracorporeal membrane oxygenation which require anticoagulation are also discussed. Lastly, those with uncommon high-risk thrombophilias, especially those with antithrombin deficiency, produce unique challenges when hospitalized.

Inferior Vena Cava Filters: Adherence to Clinical Practice Guidelines Recommendations, Retrieval Rates, and Filter Complications in a Tertiary Hospital

The present study evaluated the adherence to guideline recommendations regarding the indication for inferior vena cava filter (IVCF) placement, retrieval rates, complications, thrombotic recurrences, and mortality. Patients in whom an IVCF was placed between 2015 and 2020 in a tertiary hospital were retrospectively included. We considered absolute indication of IVCF placement if all the guidelines evaluated agreed on the indication, relative indication if only some guidelines recommended it and without indication if none of the evaluated guidelines recommended it. From the 185 patients included; 47% had an absolute indication, 15% a relative indication, and 38% had no indication. Filter-associated complications and non-removal rates were 12.4% and 41%, respectively. Venous thromboembolism recurrence rate was 17.8%, being filter-associated complications (24.2 vs 9.8%, P = .02) and thrombosis of the inferior cava or iliac veins (12.1 vs 2.6%, P = .03) more frequent in this group. The mortality rate was 40%, with higher mortality risk in patients with co-existing cancer. Previous major bleeding, filter-associated complications, and mortality were associated with a major risk of non-removal. In conclusion, the adherence to guidelines regarding the indication of IVCF placement is still low and IVCF complications are not negligible. This fact is of special concern in the elderly, comorbid, and cancer patients.

The bridging conundrum: perioperative management of direct oral anticoagulants for venous thromboembolism

Most patients diagnosed with venous thromboembolism (VTE) are currently treated with direct oral anticoagulants (DOACs). Before an invasive procedure or surgery, clinicians face the challenging decision of how to best manage DOACs. Should the DOAC be held, for how long, and are there instances where bridging with other anticoagulants should be considered? Although clinical trials indicate that most patients taking DOACs for atrial fibrillation do not require bridging anticoagulation, the optimal strategy for patients with a history of VTE is undefined. In this review, we present a case-based discussion for DOAC interruption perioperatively in patients receiving anticoagulation for management of VTE.

[Sustainable anticoagulation in COVID-19: Review of severity prediction and clinical reasoning]

OBJECTIVE

To identify the procoagulant phenomenon in SARS-CoV-2 patients and propose sustainable therapeutic guidance for low-income countries.

METHODS

A systematic review was conducted. It identified 5 observational studies from a scrutiny from 78 results. 712 patients were examined and the results were grouped according to mortality and severity. The comparison of the groups was interpreted using descriptive statistics.

RESULTS

D-dimer values were significantly associated with greater severity and mortality. Prothrombin was associated in some observations with higher mortality, but in terms of severity it was inconclusive.

CONCLUSION

COVID-19 disease has significant procoagulant activity and its timely treatment can alter the prognosis. The explored evidence supports sustainable methods. More evidence is needed to improve management. An early systematic approach to patients with sustainable therapeutic measures tailored to the health system is recommended.

Predictors of long-term outcomes after catheter-directed thrombolysis combined with stent implantation in acute deep vein thrombosis secondary to iliac vein compression

The purpose of this study is to analyze predictive factors for long-term clinical outcomes after catheter-directed thrombolysis (CDT) combined with stent implantation for acute deep vein thrombosis (DVT) secondary to iliac vein compression (IVC). A retrospective analysis was performed to review clinical data and follow-up information on 52 patients who underwent CDT combined with stent implantation for acute DVT secondary to IVC from June 2015 to March 2020. Clinical outcomes including stent patency and incidence of postthrombotic syndrome (PTS) were investigated using Kaplan-Meier analysis. All included patients were categorized into 2 groups according to the presence of PTS. Potential risk factors, including age, gender, degree of iliac vein stenosis, time from onset to treatment, dosage of thrombolytic agent, stent extending below the inguinal ligament, and duration of anticoagulation for PTS were evaluated using multivariate logistic regression analysis. Over a median follow-up of 24 months, 4 individuals underwent reintervention due to in-stent stenosis or stent compression. Primary stent patency was 98.1% at 1 month, 94.2% at 6 months, 90.4% at 12 months, and 88.5% at 24 months. Freedom from PTS was 98.1% at 6 months, 84.6% at 12 months, and 75% at 24 months. No treatment-related mortality or morbidity was observed. Based on the development of PTS, 13 patients with PTS were classified into group A and 39 patients without PTS were regarded as group B. Upon multivariate logistic regression analysis, key prognostic factors for PTS were degree of iliac vein stenosis and time from onset to treatment. CDT combined with stent implantation is safe and effective for acute DVT secondary to IVC in the long-term perspective. Severe iliac vein stenosis and longer period from onset to treatment may be associated with a higher risk of PTS.

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.

A review of inferior vena cava filters

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

Removal of inferior vena cava filter by open surgery after failure of endovenous retrieval

Background

The permanent placement of inferior vena cava (IVC) filters may lead to numerous complications and their removal is recommended once the risk of pulmonary embolism is reduced. Removal of IVC filters by endovenous means is preferred. But failure of endovenous removal happens when recycling hooks penetrate the vein wall and filters are left in place for too long time. In these scenarios, open surgery may be effective for removal of IVC filters. We aimed to describe the surgical approach, outcomes, and 6-month follow-up of the removal of IVC filter by open surgery, after the failure of removal via the endovenous method.

Methods

A total of 1,285 patients with retrievable IVC filters were admitted from July 2019 to June 2021, including 1,176 (91.5%) endovenous filter removals, and 24 (1.9%) open surgical IVC filter removals after the failure by endovenous method, of whom 21 (1.6%) were followed-up and eligible for analysis of the study. Patient characteristics, filter type, filter removal rate, IVC patency rate, and complications were retrospectively analyzed.

Results

Twenty-one patients were left with IVC filters for 26 (10, 37) months, of which 17 (81.0%) patients had non-conical filters and 4 (19.0%) had conical filters; all 21 filters were successfully removed, with a 100% removal rate, no deaths, no serious complications, and no symptomatic pulmonary embolism. At the 3rd month follow-up after surgery and 3rd month follow-up after discontinuation of anticoagulation therapy, only 1 case (4.8%) had IVC occlusion, but without any occurrence of new lower limb deep venous thrombosis and silent pulmonary embolism.

Conclusion

Open surgery can be used for the removal of IVC filters after failure of removal by endovenous method or when accompanied by complications without symptoms of pulmonary embolism. Open surgical approach can be used as an adjunctive clinical intervention for the removal of such filters.

Placing a New Filter before Removing Embolized Nonconical Filter: A Report of 13 Cases

OBJECTIVES

Permanent filter placement may result in numerous complications. Filter removal is recommended if there are no risks of pulmonary embolism. This study aimed to explore the feasibility of placing a new filter when the embolized nonconical filter is removed.

METHODS

This study included patients who had received a new filter between 2018 and 2019 before the nonconical filters were removed. Patient characteristics, new filter types, thrombus interception rate, filter removal rate, feasibility, and safety were analyzed retrospectively. Feasibility was defined as the successful placement of new filters and the removal of the nonconical filters. Safety was defined as the absence of symptomatic pulmonary embolism and inferior vena cava hemorrhage after removing the nonconical filters, as well as the successful removal of new filters without symptomatic pulmonary embolism.

RESULTS

The average indwelling period of the nonconical filters was 29 (range, 17-30) days among the 13 patients. The removal rate of the nonconical filters was 100%. Five patients (38.5%) received new Denali filters, one (7.7%) received a new Celect filter, and 7 (53.8%) received new temporary filters. Thrombi were intercepted in 10 of the patients (76.9%). The removal rate of the replaced new filters was 100%. No rupture or shifting of the new filters occurred. No symptomatic pulmonary embolism was found after the removal of both the nonconical filters and the new filters. The patients were followed up for 3 months after the surgeries, and the inferior vena cavae of 12 (92.3%) patients were patent, and no new embolic events were found.

CONCLUSIONS

Placing a new replacement filter before removal of the embolized nonconical filter may be a feasible approach to prevent pulmonary embolism. Both the nonconical filter and the new filter could be removed subsequently after the thrombi were treated.

An expert spotlight on inferior vena cava filters

Introduction: Inferior vena cava (IVC) filters are mechanical filtration devices designed as an alternative to surgical ligation/plication of the IVC. Their use has been controversial, especially with the introduction of retrievable filters and expanded/prophylactic indications.Areas covered: Authors discuss the types of available IVC filters, indications for placement, evidence on their effectiveness in general and specific patient populations, procedural considerations, off-label use, complications, and filter retrieval. This review is based on manuscripts/abstracts published from 1960 to 2021 on venous thromboembolism and IVC filters.Expert opinion: Despite the limited data on their effectiveness and survival benefit, IVC filters continue to play an important role in the treatment of patients with venous thromboembolism (VTE) who cannot receive standard anticoagulation. There is no role of IVC filters in patients without VTE. While retrievable filters are desirable for short-term use, a dedicated team-based approach, and advanced training are required for their successful removal. Newer devices are promising in improving patient safety . The device manufacturers and regulatory agencies should consider specific approaches to track device-related adverse events. Population-based studies are required to establish optimal patient population who would benefit from these devices. .

Retrievable inferior vena cava filter to prevent pulmonary embolism in patients with fractures and deep venous thrombosis of lower extremities: a single-center experience

Objective

To evaluate the effectiveness of inserting a retrievable inferior vena cava filter (IVCF) to prevent pulmonary embolism (PE) in patients with bone fractures and acute deep venous thrombosis (DVT) before major orthopedic surgery.

Methods

Clinical data of patients with fractures and acute DVT who underwent IVCF insertion were analyzed. The patients were divided into above-knee DVT (AKDVT), popliteal vein thrombosis (PVT), and below-knee DVT (BKDVT) groups.

Results

An IVCF was successfully implanted in 964 patients, among whom 929 were followed up (335, 470, and 124 in AKDVT, PVT, and BKDVT groups, respectively). There was no significant difference in the incidence of filter thrombosis among the groups (11.04%, 11.70%, and 8.06%, respectively). No symptomatic PE occurred during follow-up. The mean filter indwelling time was 18.4 ± 4.3 days, and the total filter removal rate was 76.87%. There was no significant difference in the rate of filter implantation, retrieval, complications, or mortality among the groups.

Conclusions

Retrievable filters can effectively prevent PE before orthopedic surgery in patients with fractures and acute DVT of the lower limbs. AKDVT more readily forms a ≥1-cm thrombus in the IVCF than does BKDVT, and PVT more readily forms a <1-cm thrombus than does AKDVT.

Inferior Vena Cava Filter Placement in a Duplicated Inferior Vena Cava: A Case Report

Inferior vena cava (IVC) duplication is a well-known anatomic variation that is important when relevant procedures are being planned. Duplication of IVC is a relatively rare to detect especially vascular anomaly with a prevalence of 1.5% (range 0.2-3.0%). Knowing this anatomical variation is very important in cases of IVC filter placement. Filter placement in duplicated IVC cases has many options like placing it in both vena cavae, suprarenal filter placement, or coil embolization of the intervenous segment plus placing a filter in the right IVC. We report a case of a patient with newly diagnosed bladder cancer who had a high risk of thrombosis and a recent massive pulmonary embolism. The patient was planned for transurethral resection of the bladder tumor. As a prophylactic measure, an IVC filter placement was requested to prevent further pulmonary emboli that might occur during or after surgery. Cavography showed a duplicated IVC, and the filter placement was performed in the suprarenal portion and was proved to be an adequate and safe procedure. No procedure-related complications were reported. There are few worldwide reported cases of filter placement in a duplicated vena cava, and to our best knowledge, this is the first case reported in Oman.

Dilemmas in anticoagulation and use of inferior vena cava filters in venous thromboembolism; a survey of Respiratory Physicians, Haematologists and Medical Oncologists and a review of the literature

Twenty percent of patients with Cancer Associated Thrombosis receive an inferior vena cava filter annually. Insertion is guided by practice guidelines, which do not specify or discuss the use of inferior vena cava filters in malignancy. Adherence to these guidelines is known to be variable. We aimed to see if there was consistent management of venous thromboembolism among Medical Oncologists/Haematologists and Respiratory Physicians, with respect to inferior vena cava filter use in the setting of suspected and confirmed malignancy. Medical Oncologists, Haematologists and Respiratory Physicians were surveyed with four theoretical cases. Case 1 concerns a patient who develops a pulmonary embolism following spinal surgery. Cases 2 and 4 explore the use of inferior vena cava filters in the setting of malignancy. Case 3 covers the role of inferior vena cava filters in recurrent thrombosis despite systemic anticoagulation. There were 56 responses, 32 (57%) Respiratory Physicians and 24 (43%) Haematologists/Oncologists. Respiratory Physicians were significantly more likely to insert an inferior vena cava filter in case 1 (p = 0.04) whilst Haematologists/Medical Oncologists were more likely to insert an inferior vena cava filter in case 3 (p = 0.03). No significant differences were found in cases 2 and 4. There were significant disparities in terms of type and timing of anticoagulation. Consistency of recommendations with guidelines was variable likely in part because guidelines are themselves inconsistent. The heterogeneity in responses highlights the variations in venous thromboembolism management, especially in Cancer Associated Thrombosis. International Societies should consider addressing inferior vena cava filter use specifically in the setting of Cancer Associated Thrombosis. Collaboration between interested specialities would assist in developing consistent, evidence-based guidelines for the use of inferior vena cava filters in the management of venous thromboembolism.

Inferior vena cava filters: a framework for evidence-based use

Venous thromboembolism (VTE) is a common cause of morbidity and mortality. Although most patients can be managed safely with anticoagulation, inferior vena cava filters (IVCFs) represent an important alternative to anticoagulation in a small subset of patients. IVCF use has expanded exponentially with the advent of retrievable filters. Indications for IVCFs have liberalized despite limited evidence supporting this practice. Because indiscriminate use of IVCFs can be associated with net patient harm, knowledge of the risks and benefits of these devices is essential to optimal evidence-based practice. Patients with acute VTE and absolute contraindications to anticoagulation or major complications from anticoagulation are universally agreed indications for IVCFs. However, the reliance on IVCFs for primary VTE prophylaxis in high-risk patients is not substantiated by the available literature. This review examines trends in IVCF use, practice-based recommendations on IVCF use in various clinical scenarios, complications associated with indwelling IVCFs, and indications for IVCF retrieval.

Vena caval filters for the prevention of pulmonary embolism

BACKGROUND

Pulmonary emboli (PE), or blood clots in the lungs,can be potentially fatal. Anticoagulation is the first line therapy to prevent PE. In some instances anticoagulation fails to prevent more emboli, or cannot be given because the person has a high risk of bleeding. Inferior vena caval filters (VCFs) are metal alloy devices that mechanically trap fragmented emboli from the deep leg veins en route to the pulmonary circulation. Retrievable filters are designed to be introduced and removed percutaneously. Although their deployment seems of theoretical benefit, their clinical efficacy and adverse event profile is unclear. This is the third update of a Cochrane Review first published in 2007.

OBJECTIVES

To assess the evidence for the effectiveness and safety of vena caval filters (VCFs) in preventing pulmonary embolism (PE).

SEARCH METHODS

For this review update, the Cochrane Vascular Information Specialist (CIS) searched the Specialised Register (last searched 10 September 2019) and the Cochrane Register of Controlled Trials (CENTRAL) (2019, Issue 8) via the Cochrane Register of Studies Online. The CIS also searched MEDLINE Ovid, EMBASE Ovid, CINAHL, and AMED (1 January 2017 to 10 September 2019) and trials registries to 10 September 2019.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and controlled clinical trials (CCTs) that examined the efficacy of VCFs in preventing PE.

DATA COLLECTION AND ANALYSIS

For this update, studies were assessed and data extracted independently. We assessed study quality with Cochrane's 'Risk of bias' tool and used the GRADE approach to assess the overall certainty of the evidence. The outcomes of interest were PE, mortality, lower limb venous thrombosis, filter-related complications and major bleeding.

MAIN RESULTS

We identified four new studies for this update, bringing the total to six included studies involving 1388 participants. The six studies were clinically heterogeneous and we were unable to carry out meta-analysis. Only two studies were considered to be both applicable in current clinical settings and of good methodological quality. One was a randomised open-label trial studying the effect of a retrievable inferior vena caval filter plus anticoagulation versus anticoagulation alone on risk of recurrent pulmonary embolism (PE) in 399 participants over three months. There was no evidence of a difference in the rates of PE, death, lower extremity deep vein thrombosis (DVT), or bleeding at three and six months after the intervention (moderate-certainty evidence). A filter was inserted in 193 people, but could only be successfully retrieved from 153. Minor filter complications were noted at six months. The second clinically relevant study was a randomised open-label trial of 240 participants who had sustained multiple traumatic injuries, allocated to a filter or no filter, three days after injury, in conjunction with anticoagulation and intermittent pneumatic compression. Prophylactic anticoagulation was initiated in both groups when it was thought safe to do so. There was no evidence of a difference in symptomatic PE, death, or lower limb venous thrombosis rates (moderate-certainty evidence). The only major filter complication was that one person required surgical removal of the filter. We are unable to draw any conclusions from the remaining four included studies. One study showed an increased incidence of long-term lower extremity DVT at eight years. Three studies are no longer clinically applicable because they utilised permanent filters which are seldom used now, or they did not use routine prophylactic anticoagulation which is current standard practice. The fourth study compared two filter types and was terminated prematurely as one filter group had a higher rate of thrombosis compared to the other filter type.

AUTHORS' CONCLUSIONS

Two of the six identified studies were relevant for current clinical settings. One showed no evidence of a benefit of retrievable filters in acute PE for the outcomes of PE, death, DVT and bleeding during the initial three months in people who can receive anticoagulation (moderate-certainty evidence). The other study did not show any benefit for prophylactic filter insertion in people who sustained multiple traumatic injuries, with respect to symptomatic PE, mortality, or lower extremity venous thrombosis (moderate-certainty evidence). We can draw no firm conclusions regarding filter efficacy in the prevention of PE from the remaining four RCTs identified in this review. Further trials are needed to assess vena caval filter effectiveness and safety, and clinical differences between various filter types.

Inferior vena cava filter – comprehensive overview of current indications, techniques, complications and retrieval rates

Summary: Inferior vena cava (IVC) filter has been used to manage patients with pulmonary embolism and deep venous thrombosis. Its ease of use and the expansion of relative indications have led to a dramatic increase in IVC filter placement. However, IVC filters have been associated with a platitude of complications. Therefore, there exists a need to examine the current indications and identify the patient population at risk. In this paper, we comprehensively reviewed the current indications and techniques of IVC filter placement. Further, we examined the various complications associated with either permanent or retrievable IVC filters. Lastly, we examined the current data on filter retrieval.

Inferior Vena Cava Filters: Past, Present, and Future

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

The role of interventional radiology in elective orthopaedic practice

Interventional radiology is a subspecialty of radiology that provides a range of minimally invasive diagnostic and therapeutic procedures. It continues to expand and evolve, and has had a marked impact on clinical care in many settings, in some cases averting the need for major surgery and hospital admission. While its role in the setting of trauma is relatively well established, with arterial embolisation a valuable option in the management of haemodynamically unstable patients, it is less prominent in the elective setting. This article provides an overview of emerging applications of interventional radiology in the elective treatment of orthopaedic conditions.

A review of anticoagulation in patients with central nervous system malignancy: between a rock and a hard place

The incidence and prevalence of patients who develop primary and secondary metastatic central nervous system cancer (CNS) is increasing. This is a consequence of advancements in the sensitivity and availability of diagnostic imaging, and improved therapeutic options, leading to increased detection of CNS malignancies and improved survival. These patients are at very high risk of thrombosis as well as haemorrhage, and the optimum management of anticoagulation can be challenging for treating clinicians, particularly as robust prospective evidence is sparse. In this focused review, we discuss (1) risk factors for thrombosis and bleeding in these patients, (2) management of acute venous thromboembolism (VTE) including evidence for direct oral anticoagulants, and how to approach patients with contraindications to anticoagulation, (3) ambulatory VTE prophylaxis, (4) VTE prophylaxis in patients who have undergone craniotomy for cancer, and (5) management of anticoagulation-related intracranial haemorrhage. Based on review of the available literature and author opinion, we propose practical management algorithms to aid clinicians faced with treating CNS cancer patients with thrombosis or CNS haemorrhage.

Outcomes and Prognosis Factors in Patients With Vena Cava Filters in a Quaternary Medical Center: A 5-Year Retrospective Analysis

BACKGROUND

Indications for inferior vena cava filter (IVCF) placement are controversial. This study assesses the proportion of different indications for IVCF placement and the associated 30-day event rates and predictors for all-cause mortality, deep vein thrombosis (DVT), pulmonary embolism, and bleeding after IVCF placement.

METHOD

In this 5-year retrospective cohort observational study in a quaternary care center, consecutive patients with IVCF placement were identified through cross-matching of 3 database sets and classified into 3 indication groups defined as "standard" in patients with venous thromboembolism (VTE) and contraindication to anticoagulants, "extended" in patients with VTE but no contraindication to anticoagulants, and "prophylactic" in patients without VTE.

RESULTS

We identified 1248 IVCF placements, that is, 238 (19.1%) IVCF placements for standard indications, 583 (46.7%) IVCF placements for extended indications, and 427 (34.2%) IVCF placements for prophylactic indications. Deep vein thrombosis rates [95% confidence interval] were higher in the extended (8.06% [5.98-10.58]) and prophylactic (7.73% [5.38-10.68]) groups than in the standard group (3.36% [1.46-6.52]). Mortality rates were higher in the standard group (12.18% [8.31-17.03]) than in the extended group (7.55% [5.54-9.99]) and the prophylactic (5.85% [3.82-8.52]) group. Bleeding rates were higher in the standard group (4.62% [2.33-8.12]) than in the prophylactic group (2.11% [0.97-3.96]). Best predictors for VTE were acute medical conditions; best predictors for mortality were age, acute medical conditions, cancer, and Medicare health insurance.

CONCLUSIONS

Prophylactic and extended indications account for the majority of IVCF placements. The standard indication is associated with the lowest VTE rate that may be explained by the competing risk of mortality higher in this group and related to the underlying medical conditions and bleeding risk. In the prophylactic group (no VTE at baseline), the exceedingly high DVT rate may be related to the IVCF placement.

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).

Optimal Therapy for Unstable Pulmonary Embolism

There are no randomized controlled trials of thrombolytic therapy, pulmonary embolectomy, or inferior vena cava (IVC) filters in patients with unstable pulmonary embolism (those in shock or on ventilator support). Yet, there are many investigations of these treatments based on retrospective cohort studies using administrative data from large government and commercial databases. Extensive data from these cohort studies showed that thrombolytic therapy resulted in the lowest in-hospital all-cause mortality. The results of thrombolytic therapy were greatly improved if IVC filters were added. In fact, IVC filters decreased in-hospital all-cause mortality with anticoagulants alone or with pulmonary embolectomy as well as thrombolytic therapy in adults of all ages with unstable pulmonary embolism. The IVC filters reduced mortality only if inserted on the day of admission or the next day, while the patients were unstable and in a fragile condition. We conclude that the best treatment for patients with unstable pulmonary embolism is thrombolytic therapy combined with an IVC filter inserted during the period of fragility, while the patient is unstable, and this treatment is indicated in all unstable patients irrespective of age.

Design and evaluation of a novel biodegradable inferior vena cava filter

Inferior vena cava filter has been increasingly applied in clinical practice to prevent pulmonary embolism. Nowadays, various complications after implanting conventional filters seriously hinder clinical applications. Therefore, in this paper, a novel biodegradable inferior vena cava filter was designed based on biodegradable materials, which is an hourglass-like filter anchored inside a stent structure fixed by connecting fibers. Firstly, mechanical tests in crimp were performed to study the expansion properties of the filter, showing that the biodegradable inferior vena cava filter could achieve self-expansion easily. Furthermore, the biodegradable inferior vena cava filters and fibers were incubated in phosphate buffer media (pH = 7.4 ± 0.2) at 37°C for six months. Scanning electron microscope micrograph showed that the stents exhibited no significant dimensional and structural changes and had enough radial force to support the vessel. During the degradation period, the results of scanning electron microscope, gel permeation chromatography, differential scanning calorimetry and tensile strength analysis confirmed that the degradation rate of the hourglass-like filter was faster than the connecting fibers, achieving progressive degradation and thus avoiding the polymer fragments from blocking vessel. Cytotoxicity and hemolysis assay demonstrated good biocompatibility of the filter. For 5 mm × 10 mm sized thrombus, in vitro simulated thrombus capture test showed that the mean trapping efficiency of the filter was 90%, which was comparable to traditional inferior vena cava filter. In conclusion, all results exhibited that the as-designed biodegradable inferior vena cava filter has a potential in clinical application for patients who are at temporary high risk of venous thromboembolism.

Paradoxical embolism caused by ovarian vein thrombosis extending to inferior vena cava in a female with uterine myoma

Deep vein thrombosis occasionally causes paradoxical embolism in patients with a patent foramen ovale (PFO). We report the case of a 42-year-old female who was hospitalized for stroke. Detailed investigations revealed the existence of a PFO, pulmonary embolism, and ovarian vein thrombosis extending to inferior vena cava. She had a uterine myoma to be operated on but no other thrombophilic disorders. Anticoagulation therapy with direct oral anticoagulant successfully reduced the thrombus and prevented the recurrence of paradoxical embolism. <Learning objective: Ovarian vein thrombosis (OVT) is often associated with malignancy, pelvic surgery, or pregnancy. This case shows uterine myoma as a possible cause of OVT and demonstrates the efficacy of direct oral anticoagulant for the treatment of OVT and inferior vena cava thrombosis.>.

High prevalence of deep vein thrombosis in elderly hip fracture patients with delayed hospital admission

PURPOSE

Deep vein thrombosis (DVT) is a common complication in hip fracture patients, associated with significant morbidity and mortality. Research has focused on postoperative DVT, with scant reports on preoperative prevalence. The aim of this study was to describe the prevalence of preoperative DVT in patients accessing medical care ≥ 48 h after a hip fracture.

METHODS

We included elderly patients admitted ≥ 48 h after sustaining a hip fracture, between September 2015 and October 2017. Patients with a previous episode of DVT, undergoing anticoagulation therapy, with pathologic fractures or undergoing cancer treatment were excluded. Of 273 patients, 59 were admitted at least 48 h after the fracture. DVT screening by Doppler ultrasound of both lower extremities was carried upon hospital admission. We recorded age, sex, Charlson comorbidity index and ASA score, fracture type, time since injury, time from admission to surgery and total length of hospital stay.

RESULTS

We studied 41 patients, 79 (± 10.34) years old. The delay from injury to admission was 120 h (48-696 h). Seven patients (17.1%) had a DVT upon admission. There were no significant differences between patients with and without DVT, regarding time from admission to surgery or the total length of the hospital stay.

CONCLUSIONS

The prevalence of DVT in patients admitted ≥ 48 h after a hip fracture was 17.1%. The diagnosis and management of DVT did not increase time to surgery or hospital stay. Our results suggest routine screening for DVT in patients consulting emergency services ≥ 48 h after injury.

Pearls in clinical obstetrics: challenges in anticoagulation in pregnancy

Women are at increased risk for venous thromboembolism (VTE) during both pregnancy and in the post-partum period. We have conducted a comprehensive literature review of the use of anticoagulation in pregnancy for pregnant women at increased risk for VTE. Multiple factors, including physiologic and pharmacokinetic changes make the treatment and prevention of VTE complicated in pregnancy. Adequate treatment and prevention of VTE in pregnancy is critically important, yet good quality medical studies continue to be lacking. There is a growing amount of data for the use of low molecular weight heparin (LMWH) in pregnant women and this remains the treatment of choice in most indications. For both prophylactic and therapeutic treatments, when LMWHs are chosen, monitoring of antifactor Xa level, although controversial, is advised. Women with prosthetic valve who become pregnant face challenges in regard of type of anticoagulation, dosing and monitoring during pregnancy. Delivery options and peripartum care should be defined with a multidisciplinary approach and taking patient's preference and autonomy in consideration. More high-quality research on this topic is needed to guide the clinical care of this unique population.

Association of Inferior Vena Cava Filter Placement for Venous Thromboembolic Disease and a Contraindication to Anticoagulation With 30-Day Mortality

IMPORTANCE

Despite the absence of data from randomized clinical trials, professional societies recommend inferior vena cava (IVC) filters for patients with venous thromboembolic disease (VTE) and a contraindication to anticoagulation therapy. Prior observational studies of IVC filters have suggested a mortality benefit associated with IVC filter insertion but have often failed to adjust for immortal time bias, which is the time before IVC filter insertion, during which death can only occur in the control group.

OBJECTIVE

To determine the association of IVC filter placement with 30-day mortality after adjustment for immortal time bias.

DESIGN, SETTING, AND PARTICIPANTS

This comparative effectiveness, retrospective cohort study used a population-based sample of hospitalized patients with VTE and a contraindication to anticoagulation using the State Inpatient Database and the State Emergency Department Database, part of the Healthcare Cost and Utilization Project of the Agency for Healthcare Research and Quality, from hospitals in California (January 1, 2005, to December 31, 2011), Florida (January 1, 2005, to December 31, 2013), and New York (January 1, 2005, to December 31, 2012). Data analysis was conducted from September 15, 2015, to March 14, 2018.

EXPOSURE

Inferior vena cava filter placement.

MAIN OUTCOMES AND MEASURES

Multivariable Cox proportional hazard models were constructed with IVC filters as a time-dependent variable that adjusts for immortal time bias. The Cox model was further adjusted using the propensity score as an adjustment variable.

RESULTS

Of 126 030 patients with VTE, 61 281 (48.6%) were male and the mean (SD) age was 66.9 (16.6) years. In this cohort, 45 771 (36.3%) were treated with an IVC filter, whereas 80 259 (63.7%) did not receive a filter. In the Cox model with IVC filter status analyzed as a time-dependent variable to account for immortal time bias, IVC filter placement was associated with a significantly increased hazard ratio of 30-day mortality (1.18; 95% CI, 1.13-1.22; P < .001). When the propensity score was included in the Cox model, IVC filter placement remained associated with an increased hazard ratio of 30-day mortality (1.18; 95% CI, 1.13-1.22; P < .001).

CONCLUSIONS AND RELEVANCE

After adjustment for immortal time bias, IVC filter placement was associated with increased 30-day mortality in patients with VTE and a contraindication to anticoagulation. Randomized clinical trials are needed to determine the efficacy of IVC filter placement in patients with VTE and a contraindication to anticoagulation.

Inferior vena cava filters (IVCFs): a review of uses and application to international guidelines at a single Australian center; implications of venous thromboembolism associated with malignancy

Venous thromboembolism (VTE) is a potentially lethal event. Anticoagulation is the cornerstone of treatment. Inferior vena cava filters (IVCFs) may be used in circumstances when anticoagulation is contraindicated or as an adjunct to anticoagulation. IVCF use is not without controversy due to concerns over their safety profile, differences in guidelines from international societies, and a limited randomized control trial evidence. We retrospectively undertook a review of IVCF use over a three-year period (2014–2016) at our center, which has a large oncology service but no trauma unit. There were 44 patients with successful IVCF insertion and one patient with an unsuccessful attempt. Indications for insertion included: a contraindication to anticoagulation (n = 28); recurrent VTE on anticoagulation (n = 10); and extensive VTE (n = 7). There were 13 retrieval attempts, of which ten were successful. There were five documented IVCF complications (tilting: n = 2, IVC thrombus: n = 3) with one episode of IVCF failure and two episodes of deep vein thrombosis during the follow-up period. Of the patients, 71% had an active malignancy (of whom 71% had metastatic disease). Seventeen patients died due to progressive malignancy during the study period. There were no life-threatening VTEs or IVCF-associated mortalities. Adherence with published international guidelines was variable. Patients with malignancy were less likely to undergo IVCF retrieval and had a reduced rate of retrieval success. None of the international guidelines comment on the use of IVCFs in patients with malignancy despite being commonly used. IVCF use may be an underappreciated tool in this group.

Indications, retrieval rate, and complications of inferior vena cava filters: Single-center experience in Saudi Arabia

BACKGROUND:

Inferior vena cava (IVC) filter is indicated in patients with acute venous thromboembolism (VTE) in whom therapeutic anticoagulation is contraindicated. While prophylactic insertion of an IVC filter may be considered for patients at high risk of VTE, there are significant differences between clinical guidelines on the role of IVC filters. These discrepancies have arisen predominantly because of the paucity of data on the efficacy and safety of IVC filters. We, therefore, evaluated the indications for filter insertion, the rate of filter retrieval and complications in patients who received IVC filters at King Abdulaziz Medical City (KAMC), Riyadh, Saudi Arabia.

METHODS:

A descriptive, retrospective review of electronic- and paper-based medical records was performed. Consecutive sampling was used to study all adult patients who received an IVC filter at KAMC between 2007 and 2016 and met the inclusion criteria.

RESULTS:

A total of 382 IVC filters were inserted. 113 patients (30%) had an acute VTE and a contraindication to anticoagulation while 53 patients (14%) received an IVC filter in the absence of VTE (i.e., prophylactic). Only 124 (32.5%) IVC filters were eventually retrieved. The most common reason for nonretrieval was the need for permanent filtration (155, 60%). Thrombotic complications developed in 72 (19%) patients; nine patients had fatal pulmonary embolism.

CONCLUSION:

The insertion of IVC filters in this cohort was associated with low retrieval rate and relatively high incidence of thrombotic complications. Follow-up of patients is required to detect IVC filter-related complications and to increase retrieval rate.

Reintroduction of anticoagulant therapy after intracranial haemorrhage: If and when?

Intracranial haemorrhage is a devastating complication of anticoagulation. In surviving patients, physicians will be faced with the dilemma of if and when treatment should be reintroduced. There is little evidence to support this decision making and guidelines refrain from making specific recommendations. Existing data relates almost exclusively to vitamin K antagonists and is entirely retrospective. There appears to be an overall benefit to reintroducing anticoagulation in most patients; although, this may not be advocated in those at the highest risk of recurrent bleeding. The issue of when to reintroduce treatment is more controversial. The literature suggests timing could be anywhere between 7days and 30weeks; however there is no overall consensus. This review summarises what evidence is currently available to support decision making and suggests pragmatic management options based on a risk-benefit assessment of thromboembolism and recurrent bleeding; however, it should be acknowledged this may not be entirely evidence-based.

Managing Venous Thromboembolic Disease On-Call

Managing venous thromboembolic disease on-call requires the interventional radiologist consider not only potential risk and benefit to the patient but also available resources in the IR suite as well as throughout the hospital, such as intensive care monitoring during treatment. We demonstrate how our practice manages these on-call cases ranging from deep venous thrombosis to acute pulmonary embolism and decide which patients need emergent treatment and which can undergo delayed intervention during working hours. In all cases, an adequate preprocedural clinical assessment is crucial.

Medical literature, vena cava filters and evidence of efficacy

Up to 15% of all patients with venous thromboembolism (VTE) receive an inferior vena cava filter, and prophylactic placements are increasing. To determine whether current use of filters is based on robust evidence, a global review of the recent (2001–2012) literature on filters was undertaken. The MEDLINE database was searched for articles related to filters appearing during the period 2001–2012, updating a prior search of literature from 1975–2001. All retrieved articles were analysed, classified into predetermined categories and compared to the prior analysis; randomised and large (>100 patients with a filter) comparative non-randomised clinical studies were read in full. The 651 articles, vs 568 in the period 1975–2000, consisted mainly of retrospective series (37.8%), case reports (31.7%), reviews (14.7%, vs 6.7%, p<0.001), animal and/or in vitro studies (7.5%, vs 12.9%, p=0.002), and prospective series or trials (4.9%, vs 7.4%, p=0.07). Of 4 new randomised trials (RCT), none were designed to test the efficacy of the device; to date, only one RCT has attempted to ascertain efficacy, occurring during the period 1975–2000. Eleven large non-randomised studies compared clinical outcomes of patients with and without filters, in VTE patients (n=5) or prophylactic indications (n=6); two studies found statistically significant relationships between filter use and lower mortality rates, though none could demonstrate a causal relationship. Hence, the plethoric literature on filters parallels growing experience with these devices, but still fails to provide reliable evidence that filter use improves relevant clinical outcomes. No indication for filter placement is based on appropriate scientific evidence.

AHNS Series: Do you know your guidelines? Perioperative antithrombotic management in head and neck surgery

Head and neck surgeons are commonly faced with surgical patients who have underlying medical problems requiring antithrombotic therapy. It is difficult to achieve a balance between minimizing the risk of thromboembolism and hemorrhage in the perioperative period. Data from randomized, controlled trials are limited, and procedure-specific bleed rates are also difficult to pinpoint. The decision is made more difficult when patients with moderate-to-high risk for thromboembolic events undergo procedures that are high risk for bleeding. This is true for many head and neck oncologic surgeries. Furthermore, although elective procedures may be delayed for optimization of antithrombotic medication, emergent procedures cannot. Head and neck surgery often represents the most challenging of all these circumstances, given the potential risk of airway compromise from bleeding after head and neck surgery.

Extravascular Migration of a Fractured Inferior Vena Cava Filter Strut

A 20-year-old man presented with a femur fracture and epidural hemorrhage (EDH) following a fall. One month after fracture surgery, swelling developed in both legs, and he was diagnosed as having a deep-vein thrombosis and pulmonary embolism. A retrievable inferior vena cava filter (IVCF) was inserted, because EDH is a contraindication to anticoagulants. Four months later, he complained of abdominal pain, and a computed tomography scan showed a fractured IVCF strut. After percutaneous removal failed 3 times, the IVCF was surgically removed by orthopedists using a portable image intensifier without cardiopulmonary bypass.

Inferior vena cava filters

Use of inferior vena cava (IVC) filters has increased dramatically in recent decades, despite a lack of evidence that their use has impacted venous thromboembolism (VTE)-related mortality. This increased use appears to be primarily driven by the insertion of retrievable filters for prophylactic indications. A growing body of evidence, however, suggests that IVC filters are frequently associated with clinically important adverse events, prompting a closer look at their role. We sought to narratively review the current evidence on the efficacy and safety of IVC filter placements. Inferior vena cava filters remain the only treatment option for patients with an acute (within 2-4 weeks) proximal deep vein thrombosis (DVT) or pulmonary embolism and an absolute contraindication to anticoagulation. In such patients, anticoagulation should be resumed and IVC filters removed as soon as the contraindication has passed. For all other indications, there is insufficient evidence to support the use of IVC filters and high-quality trials are required. In patients where an IVC filter remains, regular follow-up to reassess removal and screen for filter-related complications should occur.

Retrievable IVC filters - Friend or foe

Venous thromboembolism is a common condition with widely varied outcomes. Pulmonary embolism is associated with a case-fatality rate of up to 8%, increasing up to 18-fold in massive PE. Pharmacological treatment of VTE with anticoagulant medication (AC) is the first line therapy of choice. Retrievable inferior vena cava filters (IVCF) are indicated as a short-term replacement for AC in certain circumstances. Most of the evidence concerning IVCF pertains to permanent filters and older filter models. Limited evidence for retrievable IVCF results in poor consensus regarding indications, follow-up and retrieval. Complications increase with dwell-time and retrieval success rates decline. Professional bodies advocate strict guideline adherence and robust strategies for filter monitoring to maximise retrieval rate.

Effectiveness of Inferior Vena Cava Filters without Anticoagulation Therapy for Prophylaxis of Recurrent Pulmonary Embolism

OBJECTIVE

The optimal treatment of deep vein thrombosis (DVT) is anticoagulation therapy. Inferior vena cava filter (IVC) placement is another option for the prevention of pulmonary embolism (PE) in patients with deep vein thrombosis. This is used mostly in patients with a contraindication to anticoagulant therapy. The purpose of the present study was to compare the two options.

METHODS

A retrospective cohort study of two groups of patients with DVT: patients who received an IVC filter and did not receive anticoagulation due to contraindications; and patients with DVT and similar burden of comorbidity treated with anticoagulation without IVC insertion. To adjust for a potential misbalance in baseline characteristics between the two groups, we performed matching for age, gender, and Charlson's index, which is used to compute the burden of comorbid conditions. The primary outcome was an occurrence of a PE.

RESULTS

We studied 1,742 patients hospitalized with the diagnosis of DVT in our hospital;93 patients from this population received IVC filters. Charlson's score index was significantly higher in the IVC filter group compared with the anticoagulation group. After matching of the groups of patients according to Charlson's score index there were no significant differences in primary outcomes.

CONCLUSION

Inferior vena cava filter without anticoagulation may be an alternative option for prevention of PE in patients with contraindications to anticoagulant therapy.

Graduated compression stockings for the prevention of deep-vein thrombosis in postoperative surgical patients: a systematic review and economic model with a value of information analysis

BACKGROUND

Deep-vein thrombosis (DVT) can occur in surgical patients. Routine prophylaxis can be pharmacological and/or mechanical [e.g. graduated compression stockings (GCSs)]. GCSs are available in knee length or thigh length.

OBJECTIVE

To establish the expected value of undertaking additional research addressing the relative effectiveness of thigh-length GCSs versus knee-length GCSs, in addition to pharmacoprophylaxis, for prevention of DVT in surgical patients.

DESIGN

Systematic review and economic model, including value of information (VOI) analysis.

REVIEW METHODS

Randomised controlled trials (RCTs) assessing thigh- or knee-length GCSs in surgical patients were eligible for inclusion. The primary outcome was incidence of DVT. DVT complications and GCSs adverse events were assessed. Random-effects meta-analysis was performed. To draw on a wider evidence base, a random-effects network meta-analysis (NMA) was undertaken for the outcome DVT. A review of trials and observational studies of patient adherence was also conducted. A decision-analytic model was developed to assess the cost-effectiveness of thigh- and knee-length GCSs and the VOI.

RESULTS

Twenty-three RCTs were included in the review of effectiveness. There was substantial variation between trials in terms of the patient characteristics, interventions and methods of outcome assessment. Five trials comparing knee-length with thigh-length GCSs with or without pharmacoprophylaxis were pooled; the summary estimate of effect indicated a non-significant trend favouring thigh-length GCSs [odds ratio (OR) 1.48, 95% confidence interval (CI) 0.80 to 2.73]. Thirteen trials were included in the NMA. In the base-case analysis, thigh-length GCSs with pharmacoprophylaxis were more effective than knee-length GCSs with pharmacoprophylaxis (knee vs. thigh OR 1.76, 95% credible interval 0.82 to 3.53). Overall, thigh-length stockings with pharmacoprophylaxis was the most effective treatment, with a 0.73 probability of being the most effective treatment in a new trial of all the treatments. Patient adherence was generally higher with knee-length GCSs, and patients preferred knee-length GCSs. Thigh-length GCSs were found to be cost-effective in all but the subgroup with the lowest baseline risk, although the absolute differences in costs and effects were relatively small. The expected value of perfect information ranged from £0.2M to £178.0M depending on the scenario and subgroup. The relative effect parameters had the highest expected value of partial perfect information and ranged from £2.0M to £39.4M. The value of further research was most evident in the high-risk subgroups.

LIMITATIONS

There was substantial variation across the included trials in terms of patient and intervention characteristics. Many of the included trials were old and poorly reported, which reduces the reliability of the results of the review.

CONCLUSIONS

Given that the results from both the standard meta-analysis and the NMA lacked precision (CIs were wide) owing to the heterogeneous evidence base, a new definitive trial in high-risk patients may be warranted. However, the efficiency of any further research (i.e. whether this represents value for money) is dependent on several factors, including the acquisition price of GCSs, expected compliance with thigh-length GCSs wear, and whether or not uncertainty can be resolved around possible effect modifiers, as well as the feasibility and actual cost of undertaking the proposed research.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014007202.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Preventing Venous Thromboembolism in the Critically Ill — Can We do More?

Pulmonary embolism is the most common preventable cause of hospital death; and of all the different patient groups, the critically ill are particularly at risk of venous thromboembolism. Most critically ill patients have multiple risk factors. Clinical trials have shown that the use of low molecular weight heparin (LMWH) is safer than unfractionated heparin in this population. Further trials are required to look at the risks and benefits of dose adjusting LMWH at the extremes of weight, in patients with renal failure and those on antiplatelet agents. Heparin-induced thrombocytopenia is still a risk with LMWHs so a safer anticoagulant such as fondaparinux and even the new oral anticoagulants merit trials. Further evidence is also needed for the use of graduated compression stockings and pneumatic devices.

Inferior Vena Cava Filters: Guidelines, Best Practice, and Expanding Indications

Vena caval interruption, currently accomplished by percutaneous image-guided insertion of an inferior vena cava (IVC) filter, is an important therapeutic option in the management of selected patients with venous thromboembolism. The availability of optional (or retrievable) filters, in particular, has altered the practice patterns for IVC filters, with a shift to these devices and expansion of indications for filter placement. As new devices have become available and clinicians have become more familiar and comfortable with IVC filters, the indications for filter placement have continued to evolve and expand. This article reviews current guidelines and expanding indications for IVC filter placement.