Deep venous thrombosis after percutaneous insertion of vena caval filters

Delayed Arterial Hemorrhage From a Lumbar Artery Following Inferior Vena Cava Filter Placement: A Case Report

Pulmonary embolism (PE) is a feared complication of deep venous thrombosis (DVT) that can lead to respiratory distress and even death. The mainstay of preventing PE is anticoagulation, but other strategies exist. Inferior vena cava (IVC) filters are an alternative strategy for PE prophylaxis in individuals who may have contraindications to receiving anticoagulation. Although the placement of an IVC filter is a minimally invasive and typically uncomplicated procedure, all procedures have their risks. We present a case of a 35-year-old woman who experienced a rare complication of IVC filter placement and suffered a retroperitoneal hemorrhage. The patient underwent placement of an IVC filter for PE prophylaxis before a scheduled sleeve gastrectomy. Hours after placement, she returned with new symptoms and signs of blood loss. She was found to have a retroperitoneal hematoma due to bleeding from a lumbar artery that was penetrated by a strut of the filter. Arterial hemorrhage from a lumbar artery is a rare complication of IVC filter placement, and it can result in poor outcomes for the patient. We aim to increase awareness of this rare but dangerous complication to improve recognition and patient outcomes in cases of delayed arterial hemorrhage following IVC filter placement.

Does timing of IVC filter placement in bariatric surgery patients impact perioperative outcomes?

PURPOSE

Metabolic and bariatric surgery (MBS) remains a safe and effective treatment for morbid obesity with a low-risk profile. Venous thromboembolism (VTE) remains the most common cause of mortality. There is increasing consensus that inferior vena cava (IVC) filter use is associated with more harm than benefit. Our study aim was to determine if the timing of IVC filter placement correlates with VTE complications.

METHODS

The 2015-2019 Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program databases were used to identify Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) patients who had an IVC filter at the time of bariatric procedure. Selected cases were stratified by IVC placement timing. Propensity-score matching estimated the probabilities of receiving pre-existing vs. prophylactic IVC placement. Resultant models were then used to assess VTE complications. Statistical analyses were performed with Stata MP version 16. A p-value < 0.05 was considered significant.

RESULTS

In total, 228,986 RYGB and 568,386 SG cases were analyzed, and 0.6% and 0.5% had an IVC filter. Prophylactic IVC filter use declined annually, but not pre-existing filters. VTE and VTE-related mortality were significantly higher in filter vs. no filter cohorts (p<0.001). Propensity matching reduced biases between RYGB and SG IVC filter cohorts (pre-existing vs. prophylactic). There were no differences in the RYGB pre-existing and prophylactic IVC filter cohorts; however; for SG cases, pre-existing IVC filters compared to prophylactic IVC filters were associated with decreased odds of having a VTE (OR: 0.97, 95% CI: 0.95, 0.99).

CONCLUSION

Compared to a pre-existing filter, the presence of a prophylactic IVC filter in SG patients was associated with a higher likelihood of VTE.

HIGHLIGHTS

1. Annual use of prophylactic IVC filter is bariatric surgery patients is decreasing. 2. The presence of a pre-existing IVC filter remain constant. 3. Any IVC filter presence at time of MBS increased VTE and VTE-related mortality and morbidity. 4. In SG cases, prophylactic IVC filter was associated with higher rates of VTE and VTE-related mortality.

Surveillance, anticoagulation, or filter in calf vein thrombosis

OBJECTIVE

This study compared the efficacy and complication rates of inferior vena cava (IVC) filters for calf vein thrombosis (CVT) vs conservative treatment with or without anticoagulation.

METHODS

Vascular laboratory studies of patients who had an isolated CVT (anterior and posterior tibialis, peroneal, soleal, and gastrocnemius veins) from April 2009 to January 2014 were retrospectively analyzed from a single institution. Of 647 patients with isolated CVT, 285 (44%) received an IVC filter, and 362 (56%) received medical treatment alone (38.9% surveillance, 11.6% prophylactic anticoagulation, and 49.4% therapeutic anticoagulation). Univariate, multivariate, propensity matching, and Kaplan-Meier analyses were performed on abstracted data, which included, but was not limited to, risk factors, treatment modalities, venous thromboembolism (VTE) complications (defined as propagation of deep vein thrombosis [DVT] or pulmonary embolism [PE]), bleeding complications, and IVC filter-related complications (ie, filter tilting >15°, perforation >3 mm, fracture, migration >10 mm).

RESULTS

The overall incidence of PE in was 2.5% in the IVC filter group and 3.3% in the medical group (P = .27). The overall incidence of VTE complications (propagation of DVT, PE) was 35% for the surveillance group without anticoagulation, 30% in patients treated with prophylactic anticoagulation, and 10% in patients treated with therapeutic anticoagulation (P = .0003). Only a minority of patients underwent duplex ultrasound imaging after filter insertion. In the IVC filter group, the most common reasons that contraindicated anticoagulation were bleeding (35%) or recent surgery (27%). The number of IVC filter-related complications in the IVC filter group was 29 (10%). Because the IVC filter group was older (mean age, 65 vs 61 years, P = .004) and more likely to have a history of thromboembolic events (56% vs 16%, P < .0001), and malignancy (49% vs 28%, P < .0001), propensity analyses were performed yielding a homogenous cohort. The overall complication and thromboembolic rates did not differ for muscular (soleal, gastrocnemius) vs tibial DVTs (anterior, posterior, peroneal veins).

CONCLUSIONS

The use of anticoagulation in patients with CVT significantly decreases the rates of VTE complications. The use of IVC filters in this study was associated with a 10% complication rate and did not significantly reduce the incidence of PE. Nevertheless, given the overall low rates of PE and the higher risk of VTE in patients who receive filters, the decision to insert a filter in patients with calf CVT should be individualized.

ANMCO Position Paper: long-term follow-up of patients with pulmonary thromboembolism

Venous thromboembolism (VTE), including pulmonary embolism and deep venous thrombosis, is the third most common cause of cardiovascular death. The management of the acute phase of VTE has already been described in several guidelines. However, the management of the follow-up (FU) of these patients has been poorly defined. This consensus document, created by the Italian cardiologists, wants to clarify this issue using the currently available evidence in VTE. Clinical and instrumental data acquired during the acute phase of the disease are the cornerstone for planning the FU. Acquired or congenital thrombophilic disorders could be identified in apparently unprovoked VTE during the FU. In other cases, an occult cancer could be discovered after a VTE. The main targets of the post-acute management are to prevent recurrence of VTE and to identify the patients who can develop a chronic thromboembolic pulmonary hypertension. Knowledge of pathophysiology and therapeutic approaches is fundamental to decide the most appropriate long-term treatment. Moreover, prognostic stratification during the FU should be constantly updated on the basis of the new evidence acquired. Currently, the cornerstone of VTE treatment is represented by both the oral and the parenteral anticoagulation. Novel oral anticoagulants should be an interesting alternative in the long-term treatment.

Why Temporary Filters Are Not Removed: Clinical Predictors in 1,000 Consecutive Cases

BACKGROUND

Compared to permanent inferior vena cava (IVC) filters, higher complication rates occur with long-term use of temporary IVC filters. We aimed to identify patient clinical factors at the time of placement that could predict failure to remove a temporary IVC filter.

METHODS

A retrospective review was performed of both vascular surgery and interventional radiology prospective databases between December 2008 and December 2013. We analyzed a total number of 1,024 consecutive, temporary IVC filters stratified by whether retrieval was attempted or made permanent. Univariate, multivariate, and prediction modeling analyses with internal validation were performed on abstracted data, which included risk factors, treatment modalities, and indications for IVC filter placement.

RESULTS

Of 1,024 temporary IVC filters, removal was attempted in 60% and no attempt at removal (kept permanent) in 40%. Of the 619 with attempted removal, the overall successful retrieval rate was 95%. The majority of filters were not attempted to be removed because of persistent filter indications (360 cases). Risk factors associated with IVC filter permanence included male sex, older age, history, or indication of venous thromboembolism (VTE) with inability to anticoagulate, malignancy, and neurologic condition. Risk factors most predictive of permanence in the multivariate model were malignancy (odds ratio [OR]: 3.0, P < 0.001) or neurologic disorder (OR: 2.69, P = 0.0005). Validation revealed our model had a sensitivity of 60.4% and specificity of 69.9%.

CONCLUSIONS

Our study shows that patients who are more likely to have a temporary IVC filter kept permanent are more likely to be older males with a history of malignancy, neurologic condition, or VTE. These factors are also predictive of permanence and can be used in our predictive model to provide insight into the significant preoperative risk factors that should play into the decision-making process.

A multidisciplinary quality improvement program increases the inferior vena cava filter retrieval rate

Published reports indicate low retrieval rates for retrievable inferior vena cava (IVC) filters. We performed a historic-controlled study of a 5-year intervention (March 2007 to February 2012) to improve IVC filter retrieval rates at a university medical center serving a rural area. All adults with a retrievable filter placed were included, except those with a life expectancy <6 months. The intervention included initial verbal counseling and printed educational materials, correspondence after discharge, and a hematology consultation. The control group included patients with retrievable filters placed in the 15 months preceding study initiation. In the control group, 116 filters were placed and 27 (23%) were removed, compared to 378 filters placed and 169 (45%) removed during the intervention. Adjusting for patient characteristics, the odds ratio of retrieval during the intervention was 3.03 (95% CI 1.85–4.27) compared to the control period. An intervention including patient education and hematology follow-up appeared to significantly improve IVC filter retrieval rates.

In-Vitro Evaluation of a New Inferior Vena Cava Filter—The Stent-Filter

Inferior vena cava filters are indicated for the prevention of pulmonary embolism when anticoagulation using heparin has failed or is contraindicated. The aim of this study was to assess in an in-vitro setting the efficiency of a new inferior vena cava filter to intercept emboli. The new filter, stent-filter, was inserted into a pulsating flow circuit. Then thrombi were produced by introducing sheep's blood into silicon tubes with 3 mm diameter. A combination of 9% saline solution with 40% glycerol was used as the isosmotic fluid in the circuit. A total of 150 thrombi were introduced into the circuit in 3 stages of 50 events each. The flow rate in each of the 3 stages was altered; initially a rate of 1.0 liter per minute was chosen, and after this, it was increased to 1.5 liters and finally 2.0 liters per minute. The percentage of interceptions was used for statistical analysis. In the in-vitro experiment, the filter captured 94%, 90%, and 92% of the thrombi at flow rates of 1.0, 1.5, and 2.0 liters per second, respectively. In conclusion the new filter was effective in the interception of the thrombi when it was evaluated in in-vitro conditions.

Placement of vena cava filter via percutaneous puncture of the great saphenous vein

The aim of this study was to investigate the feasibility and safety of vena cava filter (VCF) placement via percutaneous puncture of the great saphenous vein (GSV) in the prevention of pulmonary embolisms. Using ultrasound positioning, VCF placement via percutaneous puncture of the GSV was performed on 12 patients with deep vein thrombosis (DVT) in the lower extremities. Transcatheter thrombolysis was conducted simultaneously. The postoperative filter position, puncture wound recovery and fluency of the GSV were observed. All filters were successfully released, with accurate positioning. No hematoma was observed at the puncture point during the perioperative period. In certain patients, local petechiae appeared around the puncture point during the thrombolysis period, which did not require special treatment. Re-examination using ultrasound revealed unobstructed blood flow in the GSV. VCF placement via percutaneous puncture of the GSV is a new filter placement method. The feasibility and safety of this method for the prevention of pulmonary embolisms has been demonstrated in a small number of sample cases.

Implante profilático e temporário de filtro de veia cava inferior no trauma

O tromboembolismo pulmonar (TEP) é importante causa de óbito no trauma e esse, na maioria das vezes, contraindica a principal farmacoterapia na prevenção e no tratamento do TEP: a anticoagulação. Relatamos um caso de paciente politraumatizado, com risco elevado de embolia pulmonar, submetido ao implante preventivo e temporário de filtro de veia cava inferior (FVC).

Complications of inferior vena caval filters

Inferior vena caval filters have been shown to be effective in the prevention of pulmonary embolism, with low morbidity and mortality associated with their implantation. Awareness of potential complications can further decrease the risk of filter placement and lead to early detection and management of complications to improve clinical outcomes. The purpose of this article is to review the procedure-related and delayed complications associated with inferior vena caval filters.

Vena cava filter occlusion and venous thromboembolism risk in persistently anticoagulated patients: a prospective, observational cohort study

BACKGROUND

Inferior vena cava (IVC) filter placement may be life-saving, but after contraindications to anticoagulation remit, patient management is uncertain.

METHODS

We followed patients who had venous thromboembolism, followed by treatment with permanent IVC filter placement, and were anticoagulated long-term as soon as safety allowed. We conducted annual physical examinations and ultrasound surveillance of the lower extremity deep veins and of the IVC filter site. Clot detected at the filter site was treated with graded intensities of anticoagulation, depending on the clot burden.

RESULTS

Symptomatic DVT occurred in 24 of 121 patients (20%; 95% CI, 14%-28%); symptomatic pulmonary embolism (one fatal) was diagnosed in six patients (5%; 95% CI, 2%-10%). There were 45 episodes of filter clot in 36 patients (30%; 95% CI, 22%-38%). The rate of major bleeding (6.6%) was similar to that of a concurrent persistently anticoagulated cohort without IVC filters (5.8%).

CONCLUSIONS

If therapeutic anticoagulation can be safely begun in patients with IVC filters inserted after venous thromboembolism, further management with clinical surveillance, including ultrasound examination of the IVC filter and graded degrees of anticoagulation therapy if filter clot is detected, has a favorable prognosis. This approach appears valid for patients with current IVC filter and can serve as a comparison standard in subsequent clinical trials to optimize clinical management of these patients.

Insertion of inferior vena cava filters in patients with the antiphospholipid syndrome

BACKGROUND

The antiphospholipid syndrome (APS) is a disease with a high prevalence of thromboembolic events, especially pulmonary emboli (PE). These events may recur despite anticoagulation therapy. In such cases, placement of an inferior vena cava (IVC) filter may be considered to prevent propagation of a distal thrombus toward the pulmonary vessels. It is unclear whether the placement of such a filter is beneficial in patients with APS.

OBJECTIVE

Retrospective evaluation of the value of IVC filter placement as prophylaxis against recurrent pulmonary emboli in patients with medically treated APS.

METHODS

We identified 10 patients suffering from APS who, despite anticoagulation treatment, had recurrent thromboembolic events. All of them underwent placement of an IVC filter. We examined their medical files for further recurrences.

RESULTS

Of the 10 patients in our study, only 1 had a documented PE following the intervention. The remaining patients had no evidence of PE after the filter insertion. Five of the 10 patients died, 2 of them suddenly. In those 2 patients, the cause of death is unknown, but PE cannot be excluded.

CONCLUSION

IVC filters seem to be protective against recurrent PE in APS patients but the true extent of their efficacy requires further study.

Intravascular ultrasound-guided bedside placement of inferior vena cava filters

Pulmonary emboli in a critically ill patient population is an occurrence that may be reduced with appropriate utilization of inferior vena cava (IVC) filters. Complications both during transfer or transport of critically ill patients who are dependent upon multiple intravenous drips, ventilators and intensive monitoring may be reduced with bedside placement of inferior vena cava filters. Over the last decade, investigators have been developing techniques for bedside IVC filter placement based on intravascular ultrasound techniques. We discuss and detail a single venous access technique of IVC filter placement using intravascular ultrasound.

Retrievable inferior vena cava filters may be safely applied in gastric bypass surgery

INTRODUCTION

Pulmonary embolus (PE) is a potentially devastating and fatal postoperative complication in morbidly obese patients. This study was undertaken to review the safety and efficacy of retrievable prophylactic inferior vena cava (IVC) filters in high-risk morbidly obese patients undergoing gastric bypass.

METHODS

Patients who underwent gastric bypass surgery and preoperative insertion of retrievable IVC filters had their records reviewed. Indications for IVC filter insertion were: history of deep venous thrombosis (DVT) or PE, long-standing sleep apnea, venous stasis disease, and/or weight > 400 pounds.

RESULTS

24 patients underwent IVC filter placement before gastric bypass surgery. There were 10 women and 14 men with an average age of 50 +/- 6.3 years (range 39 to 59) and average body mass index (BMI) of 57 +/- 7.5 kg/m(2) (range 49 to 74). BMI greater then 50 kg/m(2) was present in 21 of 24 patients (88%). All patients had successful IVC filter placement. IVC filter retrieval postoperatively was performed in 20 of 24 patients (83%) with three left for clinical reasons and one (4%) left due to technical inability to retrieve. There was one complication directly attributable to IVC filter retrieval. There were no deaths. Five patients (21%) developed DVT or PE postoperatively. Follow-up was 16 +/- 7.6 months (range 8 to 33).

CONCLUSIONS

Prophylactic IVC filter placement and retrieval can be safely undertaken in high-risk gastric bypass patients. We recommend preoperative IVC filter placement in selected patients.

Retrospective analysis of the use of inferior vena cava filters in routine hospital practice

INTRODUCTION

Characteristics and outcomes of patients undergoing inferior vena cava (IVC) filter insertion are not well reported. Particularly, the role of long term anticoagulation in these patients is unclear.

AIMS

(1) To describe in a cohort of patients undergoing IVC filter insertion, underlying diseases, indications for filter insertion, complications, and survival. (2) To determine the effect of long term anticoagulant treatment on thromboembolism and patient survival.

STUDY DESIGN

A retrospective analysis of 109 consecutive patients undergoing IVC filter insertion in two university hospitals.

RESULTS

Average age was 67.4 years. Median duration of follow up was two years. Indications for IVC filter insertion were: contraindication to anticoagulation (n = 61, 56%), prophylactic insertion (n = 29, 27%), thromboembolism while receiving adequate anticoagulation (n = 17, 15%), and non-compliance with anticoagulation (n = 2, 2%). Insertion related complications were groin haematoma in four patients (3.5%) and localised infection at the puncture site in one patient (0.9%). Fifty six patients (51.4%) died during the study period. Of these, 22 received long term anticoagulants and 34 did not. Overall and thrombosis free survival was greater in the anticoagulant treated group (median survival not reached) than in the untreated group (median survival = 12 months). Patients not receiving long term anticoagulation after IVC filter insertion were nearly 2.5-fold more likely to die or experience venous thromboembolism.

CONCLUSION

IVC filter insertion was a safe procedure and was performed for appropriate indications in the patients studied. In patients surviving for longer than 30 days, prolonged administration of oral anticoagulants was associated with improved survival with no significant increase in haemorrhagic complications.

Retrievable Inferior Vena Cava Filters: Initial Clinical Results

Anticoagulation is the accepted therapy for patients with thromboembolic disease. When contraindications to anticoagulant therapy are present, however, interruption of the inferior vena cava (IVC) may prevent pulmonary embolism (PE). The objective of this study was to report our early technical and clinical results with retrievable IVC filters (IVCFs) for the prevention of PE. One hundred and twenty-seven multitrauma patients between December 1, 2002, and December 31, 2004, underwent placement of Gunther-Tulip (n = 49), Recovery (n = 41), or OptEase (n = 37) retrievable IVCFs under real-time intravascular ultrasound (IVUS) guidance. All patients had abdominal X-rays to verify filter location. Prior to IVCF retrieval, all patients underwent femoral vein color flow ultrasonography to rule out deep vein thrombosis (DVT) and vena-cavography to assess the IVCF for trapped emboli, filter tilt, or retrained thrombus. Thirty-nine patients died of their injuries; no deaths were related to IVCF placement. One PE occurred during follow-up after filter retrieval, and two femoral vein insertion-site DVTs occurred. One hundred twenty (94.4%) of IVCFs were placed without complication at the L2-3 level, as verified by abdominal X-rays. Filter-related complications included three groin hematomas (2.9%) and three IVCFs misplaced in the right iliac vein early in our experience (2.3%); these filters were uneventfully retrieved and replaced in the IVC within 24 hr. Sixty-six patients underwent uneventful retrieval of IVCFs after DVT or PE anticoagulation prophylaxis was initiated. Forty-five IVCFs were not removed: 41 due to contraindications due to anticoagulation and four because of trapped thrombus within the filter. The role of retrievable IVCFs continues to evolve, but in this study of 127 patients, prophylactic temporary IVCF placement was simple and safe, prevented fatal PE, and served as an effective "bridge" to anticoagulation. Further investigation of this bedside IVUS technique and the role of temporary IVCFs in different patient populations is warranted.

The prophylactic use of inferior vena cava filters in patients undergoing high-risk spinal surgery

Prophylactic inferior vena cava filter (IVCF) placement is advocated in some high-risk groups. We sought data regarding safety and efficacy for prophylactic IVCF placement in patients at high risk for venous thromboembolism (VTE) following major spinal reconstruction. Seventy-four spine surgery patients with contraindication to anticoagulation (44 females, 30 males; mean age 56.2) received prophylactic IVCFs. Criteria were (1) history of thromboembolism, (2) diagnosed thrombophilia, (3) malignancy, (4) bedridden >2 weeks prior to surgery, (5) staged procedures or multiple levels, (6) combined anterior/posterior approaches, (7) expected need for significant iliocaval manipulation during exposure, and (8) single-stage anesthetic time >8 hr. Seventy patients had at least two risk factors. All received IVCFs prior to the first stage of spine reconstruction. Patients were evaluated for filter complications, deep vein thrombosis (DVT), and pulmonary embolism (PE). Patients' lower extremity veins from groin to ankle were imaged weekly until discharge using duplex ultrasound (DUS). One-third also underwent thoracic and pelvic computed tomography scans, and the pelvic veins, IVC, and pulmonary vasculature were evaluated for VTE. Multiple DUS (n = 198, mean 2.6 studies per patient) were performed in 68 patients. At a mean follow-up of 11 months, one of the patients developed PE. Twenty-seven limbs in 23 patients developed DVT. Five limbs had isolated calf DVT, and 22 had proximal vein involvement. Insertion site DVT accounted for nearly one-third of the DVTs. Six patients died from unrelated complications. There was one technical error with an IVCF deployed in the iliac vein. Despite a high incidence of DVT following high-risk spinal surgery, prophylactic IVCF placement appears to protect patients from PE.

Retrieval of a Malpositioned Vena Cava Filter with Embolic Protection with Use of a Second Filter

Proper positioning of inferior vena cava (IVC) filters is necessary for effective protection from pulmonary embolism (PE). This report describes a case of an IVC filter malpositioned partially in the right common iliac vein that resulted in risk of recurrent PE caused by thrombus emanating from the left common iliac vein. A new filter was placed in the IVC above the first device, followed by retrieval of the malpositioned filter through the new filter.

Comparison of Bedside Transabdominal Duplex Ultrasound versus Contrast Venography for Inferior Vena Cava Filter Placement: What Is the Best Imaging Modality?

While contrast venography is considered the gold standard for imaging prior to inferior vena cava (IVC) filter insertion, bedside placement via transabdominal duplex ultrasound (DUS) has been recognized as a safe and effective alternative. To date, there has been no direct comparison of the efficacy of both imaging modalities for IVC filter placement. A concurrent cohort of patients who underwent IVC filter placement at a single institution over a 7-year period with either contrast venography or transabdominal DUS performed at bedside was retrospectively reviewed. Patient demographics, venous thromboembolism risk factors, indications, technical success, and procedural complications were compared. Of 439 patients initially imaged with transabdominal DUS, IVC filter placement was determined to be technically feasible in 382 patients (87%). The procedural technical success rate for IVC filter placement using transabdominal DUS when IVC visualization was adequate was 97.4% (n = 382 patients), compared to 99.7% (n = 318 patients) for contrast venography (p = 0.018). Patients undergoing IVC filter placement with transabdominal DUS more commonly required IVC filter for venous thromboembolism prophylaxis (81.1% vs. 27.8%, p < 0.001), had increased incidence of multiple traumatic injuries (28% vs. 10%, p < 0.001), and had increased risk from immobilization (91.3% vs. 34.1%, p < 0.001). Overall complication rates were 0.6% for venography and 1.8% for transabdominal DUS (p = NS). When IVC visualization was adequate, contrast venography and transabdominal duplex ultrasound both had high rates of success and a low incidence of complications. A technical success advantage was observed for contrast venography; this difference in technical success must be weighed against the bedside insertion advantage offered by DUS, which may be especially important in the immobilized or critically ill patient. Transabdominal DUS remains our preferred technique when feasible, especially when bedside placement is desired.

Avaliação in vitro de um novo filtro de veia cava

OBJETIVO: O objetivo do estudo foi avaliar a eficácia de um novo filtro de veia cava, de baixo perfil, na retenção de coágulos em modelo in vitro. MÉTODO: O filtro consiste em dois cones opostos pelo ápice. O cone distal é formado por oito hastes de aço inoxidável, que têm a função de retenção dos êmbolos. O cone proximal é constituído de quatro hastes, cuja função é ancorar e centralizar. Os filtros foram introduzidos e fixados no interior de um tubo de PVC transparente de 25, 30 e 35 mm de diâmetro interno, em posição vertical, e conectados com um sistema pulsátil de fluxo (bomba peristáltica). Foi utilizado, para veículo, um reservatório com solução salina (0,9%) com 40% de glicerina, mantido em temperatura ambiente. Confeccionaram-se trombos com sangue bovino em tubos plásticos de 3, 4,5 e 6 mm de diâmetro e, posteriormente, foram segmentados nas medidas de 10, 15, 20 e 30 mm de comprimento, totalizando 12 diferentes tamanhos. Realizaram-se 100 liberações para cada tipo de êmbolo e tamanho das cânulas, totalizando 3.600 eventos. Foram feitos lançamentos seqüenciais com cinco êmbolos, sendo 10 para cada tamanho de êmbolo e cânulas, totalizando 360 eventos. Fez-se avaliação da capacidade de retenção dinâmica utilizando os três diferentes tamanhos de cânulas com 100 eventos cada, totalizando 300 eventos. RESULTADOS: Detectou-se que o diâmetro e comprimento dos êmbolos, assim como diâmetros da cânula, podem comprometer a eficácia do filtro. A média de captura de êmbolos pelos filtros foi de 80,5% nas cânulas de 35 mm, 88,7% para cânulas de 30 mm e 86,6% para cânulas de 25 mm. CONCLUSÃO: Conclui-se que a eficácia desse filtro sofre interferência relacionada ao tamanho dos êmbolos e diâmetro da cânula.

Role of prophylactic temporary inferior vena cava filters placed at the ICU bedside under intravascular ultrasound guidance in patients with multiple trauma

OBJECTIVE

Patients with multiple trauma often have injuries that preclude the use of anticoagulation therapy or sequential compression device prophylaxis. Temporary inferior vena cava (IVC) filters (IVCFs) offer protection against pulmonary embolism during the early immediate injury and perioperative period, when risk is highest, while averting potential long-term sequelae of permanent IVCFs. The objective of this study was to evaluate the efficacy of prophylactic, temporary IVCF placement at the intensive care unit bedside under real-time intravascular ultrasound (IVUS) guidance in patients with multiple trauma.

INTERVENTIONS

Ninety-four patients with multiple trauma seen between July 1, 2002, and November 1, 2003, underwent placement of OptEase (Cordis Endovascular) retrievable IVCFs under real-time IVUS guidance. Mean (+/-SD) Injury Severity Score was 25.1 +/- 2.2). Abdominal x-ray films were obtained in all patients to verify filter location. Before IVCF retrieval all patients underwent femoral vein color-flow ultrasound scanning to rule out deep vein thrombosis (DVT), and pre-procedure and post-procedure vena cavography to identify possible IVCF thrombus entrapment and post-retrieval inferior vena cava injury.

RESULTS

Nineteen patients died of their injuries; no deaths were related to IVCF placement. One pulmonary embolism occurred during follow-up after filter retrieval, and 1 insertion site femoral vein DVT occurred. As verified on abdominal x-ray films, 96.8% (91 of 94) of IVCFs were placed without complications at the L2-3 level. Filter-related complications included 2 groin hematomas (2.1%) and 3 IVCFs misplaced in the right iliac vein (3.2%), early in our experience; the filters were uneventfully retrieved and replaced in the inferior vena cava within 24 hours. Thirty-one patients underwent uneventful retrieval of IVCFs after DVT or pulmonary embolism anticoagulation prophylaxis was initiated. Forty-four filters were not removed, 41 because severity of injury prevented DVT or pulmonary embolism prophylaxis and 3 because of thrombus trapped within the filter.

CONCLUSIONS

Prophylactic, temporary IVCF placement at the intensive care unit bedside under IVUS guidance in patients with multiple trauma is simple and safe, and serves as an effective "bridge" to anticoagulation therapy until venous thromboembolism prophylaxis can be initiated. Further investigation of this bedside technique and the role of temporary IVCFs in patients with multiple trauma is warranted.

CLINICAL RELEVANCE

Patients with multiple trauma often have injuries that preclude the use of anticoagulation therapy or sequential compression device prophylaxis. Temporary inferior vena cava filters (IVCFs) offer protection against pulmonary embolism during the perioperative and immediate injury period, when risk is highest. Ninety-four patients with multiple trauma underwent prophylactic, temporary IVCF placement at the intensive care unit bedside under real-time intravascular ultrasound. One pulmonary embolism occurred during follow-up after filter retrieval, and 1 insertion site femoral vein deep venous thrombosis occurred. Ninety-one of 94 IVCFs (96.8%) were placed without complication. Thirty-one patients underwent uneventful retrieval of IVCFs after anticoagulation prophylaxis was initiated. Forty-four filters were not removed, because of severity of injury (n = 41) or because of trapped thrombus within the filter (n = 3). Prophylactic, temporary IVCFs placed under intravascular ultrasound guidance at the bedside in patients with multiple trauma is simple, safe, and an effective bridge to anticoagulation therapy.

Prevention of venous thromboembolism: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy

This article discusses the prevention of venous thromboembolism (VTE) and is part of the Seventh American College of Chest Physicians Conference on Antithrombotic and Thrombolytic Therapy: Evidence-Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004; 126:179S-187S). Among the key recommendations in this chapter are the following. We recommend against the use of aspirin alone as thromboprophylaxis for any patient group (Grade 1A). For moderate-risk general surgery patients, we recommend prophylaxis with low-dose unfractionated heparin (LDUH) (5,000 U bid) or low-molecular-weight heparin (LMWH) [< or = 3,400 U once daily] (both Grade 1A). For higher risk general surgery patients, we recommend thromboprophylaxis with LDUH (5,000 U tid) or LMWH (> 3,400 U daily) [both Grade 1A]. For high-risk general surgery patients with multiple risk factors, we recommend combining pharmacologic methods (LDUH three times daily or LMWH, > 3,400 U daily) with the use of graduated compression stockings and/or intermittent pneumatic compression devices (Grade 1C+). We recommend that thromboprophylaxis be used in all patients undergoing major gynecologic surgery (Grade 1A) or major, open urologic procedures, and we recommend prophylaxis with LDUH two times or three times daily (Grade 1A). For patients undergoing elective total hip or knee arthroplasty, we recommend one of the following three anticoagulant agents: LMWH, fondaparinux, or adjusted-dose vitamin K antagonist (VKA) [international normalized ratio (INR) target, 2.5; range, 2.0 to 3.0] (all Grade 1A). For patients undergoing hip fracture surgery (HFS), we recommend the routine use of fondaparinux (Grade 1A), LMWH (Grade 1C+), VKA (target INR, 2.5; range, 2.0 to 3.0) [Grade 2B], or LDUH (Grade 1B). We recommend that patients undergoing hip or knee arthroplasty, or HFS receive thromboprophylaxis for at least 10 days (Grade 1A). We recommend that all trauma patients with at least one risk factor for VTE receive thromboprophylaxis (Grade 1A). In acutely ill medical patients who have been admitted to the hospital with congestive heart failure or severe respiratory disease, or who are confined to bed and have one or more additional risk factors, we recommend prophylaxis with LDUH (Grade 1A) or LMWH (Grade 1A). We recommend, on admission to the intensive care unit, all patients be assessed for their risk of VTE. Accordingly, most patients should receive thromboprophylaxis (Grade 1A).

Patients with inferior vena caval filters should receive chronic thromboprophylaxis

A 32-year-old man with testicular carcinoma is diagnosed with an acute left leg deep venous thrombosis (DVT) during his fourth cycle of combination chemotherapy. Because of anticipated moderate to severe thrombocytopenia, anticoagulation is initially avoided and an inferior vena cava (IVC) filter is placed to prevent pulmonary embolism (PE). After completion of all chemotherapy he is deemed to be in remission and anticoagulation is begun. The optimal duration of anticoagulation in this patient is pondered.

Aortic pseudoaneurysm from aortic penetration with a bird's nest vena cava filter

This is a case report of a 29-year-old woman with an infected aortic pseudoaneurysm. Two years previously a bird's nest vena cava filter was placed after complex gastric surgery. Imaging studies and operative findings showed that the pseudoaneurysm was caused by penetration of the aorta by a prong of the vena cava filter.

Acute complications associated with greenfield filter insertion in high-risk trauma patients

BACKGROUND

Use of Greenfield filters (GFs) to prevent fatal pulmonary embolism (PE) in trauma patients is generally well accepted. Nonetheless, a surprisingly small number of trauma surgeons insert filters in their patients. Among the reasons cited is fear of complications.

METHODS

We observed three femoral arteriovenous fistulae (AVF) in trauma patients who had inferior vena caval placement of filters for PE prophylaxis in one 12-month period (academic year 1999). In an effort to document the magnitude of this problem, we evaluated trauma patients who had a GF inserted in academic year 2000.

RESULTS

During that year, 133 consecutive patients (8.6% of trauma admissions) received 133 GFs through a percutaneous approach. The most common isolated indications for GF insertion included closed head injuries (n = 28), multiple long bone fractures (n = 27), pelvic and acetabular fractures (n = 6), spinal cord injuries (n = 16), and vertebral fractures (n = 3). Five patients had documented deep venous thrombosis (DVT) diagnosed by duplex ultrasonography before GF placement, and 11 patients had other indications requiring a filter. There were 37 patients with more than one indication requiring filter placement. Most patients (57%) underwent preinsertion duplex scanning of their lower extremity veins; 77% of patients underwent postinsertion scanning. Filters were inserted an average of 6.8 +/- 0.6 (SE) days after trauma. No AVF were suspected clinically or detected ultrasonographically. No operative or postoperative complications occurred. DVT was observed in 30% of patients despite 92% prophylaxis; there was a 26% incidence of de novo thrombi detected. None of the patients evidenced DVT clinically.

CONCLUSION

Our data indicate that complications of GF insertion for prophylaxis against PE from DVT complicating trauma patients continue to be negligible. In addition, the incidence of insertion-site thrombosis may be lower than expected. Moreover, femoral AVF is a rare complication of this procedure.

Vena caval filters: a comprehensive review

Hematologists are often asked to treat patients with venous thromboembolic disease. Although anticoagulation remains the primary therapy for venous thromboembolism, vena caval filters are an important alternative when anticoagulants are contraindicated. To assess the evidence supporting the utility of these devices, a comprehensive review of the English language literature was performed. Except for one randomized trial, the vena caval filter literature consists of case series or consecutive case series. The mean duration of follow-up for each of the 5 filter types varies from 6 to 18 months. All are about equally effective in the prevention of pulmonary embolism (2.6%-3.8%). Deep venous thrombosis (6%-32%) and inferior vena cava thrombosis (3.6%-11.2%) after filter placement vary widely among different filter types primarily because of differences in outcome assessment. Thrombosis at the insertion site is a common complication of filter placement (23%-36%). In view of the absence of randomized comparisons, no filter can be designated as superior in safety or efficacy. Vena caval filters represent a potentially important but poorly evaluated therapeutic modality in the prevention of pulmonary emboli. Randomized trials are necessary to establish the appropriate place for vena caval filters in the treatment of venous thromboembolic disease.

Vena caval filters: a comprehensive review

Hematologists are often asked to treat patients with venous thromboembolic disease. Although anticoagulation remains the primary therapy for venous thromboembolism, vena caval filters are an important alternative when anticoagulants are contraindicated. To assess the evidence supporting the utility of these devices, a comprehensive review of the English language literature was performed. Except for one randomized trial, the vena caval filter literature consists of case series or consecutive case series. The mean duration of follow-up for each of the 5 filter types varies from 6 to 18 months. All are about equally effective in the prevention of pulmonary embolism (2.6%-3.8%). Deep venous thrombosis (6%-32%) and inferior vena cava thrombosis (3.6%-11.2%) after filter placement vary widely among different filter types primarily because of differences in outcome assessment. Thrombosis at the insertion site is a common complication of filter placement (23%-36%). In view of the absence of randomized comparisons, no filter can be designated as superior in safety or efficacy. Vena caval filters represent a potentially important but poorly evaluated therapeutic modality in the prevention of pulmonary emboli. Randomized trials are necessary to establish the appropriate place for vena caval filters in the treatment of venous thromboembolic disease.