Five-year follow-up of prophylactic vena cava filters in high-risk trauma patients

Immediate and Delayed Complications of IVC Filters

OBJECTIVE

Inferior vena cava (IVC) filter placement has increased dramatically in the past two decades. However, literature supporting the efficacy of these devices has been limited and controversial. In the present study, we have evaluated the predictors and rates of technical complications after IVC filter insertion in a large national database.

METHODS

The Vascular Quality Initiative registry was explored (January 2013 to December 2020). Immediate complications were defined as venous injury requiring treatment, filter misplacement (failure to open, deployed >20 mm from intended site or in wrong vein, embolized to the heart), angulation >20°, and insertion site complications. Delayed complications were defined as migration, angulation >15°, fracture, caval and/or iliac thrombosis, filter thrombus, fragment embolization, and perforation. The Pearson χ² test was used to compare the baseline characteristics between the patients who had developed immediate and/or delayed complications and those who had not. The predictors of these complications were evaluated using multivariable logistic regression, Cox proportional hazard regression, and Kaplan-Meier survival analysis.

RESULTS

A total of 14,784 patients were included in the present analysis, with a median follow-up of 11 months (interquartile range, 4-16 months). The rate of immediate and delayed complications was 1.8% and 3.1%, respectively. Angulation (1.2%) was the most common immediate complication, and filter thrombosis (1.6%) was the most common delayed complication. Compared with the patients with no immediate complications, those with immediate complications were more likely to have had abnormal anatomy (6.0% vs 1.7%; P < .001) and a landing zone other than infrarenal (7.0% vs 4.2%; P = .02). Compared with their counterparts, those with delayed complications were less likely to have received statins (21.0% vs 29.5%; P = .006) and were more likely to have a family history of venous thromboembolism (8.0% vs 5.1%; P = .047). Logistic regression analysis revealed that renal vein visualization was associated a 50% reduction (adjusted odds ratio [aOR], 0.50; 95% confidence interval [CI], 0.27-0.92; P = .027) in the odds of immediate complications and female sex and abnormal anatomy were associated with a 41% (aOR, 1.41; 95% CI, 1.08-1.85; P = .013) and 244% (aOR, 3.44; 95% CI, 1.66-7.16; P < .001) increase in the odds of immediate complications, respectively. Immediate (P = .21) and delayed (P = .51) complications did not result in increased mortality.

CONCLUSIONS

The immediate and delayed IVC filter complication rates were 1.8% and 3.1%, respectively, but the occurrence of complications was not associated with increased mortality. Female sex was associated with an increase in the development of immediate complications. The incidence of immediate complications might be mitigated if advanced imaging were used for renal vein visualization before IVC filter deployment. Delayed complications might be avoided if IVC filter retrieval were performed in a timely fashion and institutional retrieval protocols were optimized.

In Vitro Clot Trapping Efficiency of the FDA Generic Inferior Vena Cava Filter in an Anatomical Model: An Experimental Fluid-Structure Interaction Benchmark

PURPOSE

Robust experimental data for performing validation of fluid-structure interaction (FSI) simulations of the transport of deformable solid bodies in internal flow are currently lacking. This in vitro experimental study characterizes the clot trapping efficiency of a new generic conical-type inferior vena cava (IVC) filter in a rigid anatomical model of the IVC with carefully characterized test conditions, fluid rheological properties, and clot mechanical properties.

METHODS

Various sizes of spherical and cylindrical clots made of synthetic materials (nylon and polyacrylamide gel) and bovine blood are serially injected into the anatomical IVC model under worst-case exercise flow conditions. Clot trapping efficiencies and their uncertainties are then quantified for each combination of clot shape, size, and material.

RESULTS

Experiments reveal the clot trapping efficiency increases with increasing clot diameter and length, with trapping efficiencies ranging from as low as approximately 42% for small 3.2 mm diameter spherical clots up to 100% for larger clot sizes. Because of the asymmetry of the anatomical IVC model, the data also reveal the iliac vein of clot origin influences the clot trapping efficiency, with the trapping efficiency for clots injected into the left iliac vein up to a factor of 7.5 times greater than that for clots injected into the right iliac (trapping efficiencies of approximately 10% versus 75%, respectively).

CONCLUSION

Overall, this data set provides a benchmark for validating simulations predicting IVC filter clot trapping efficiency and, more generally, low-Reynolds number FSI modeling.

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.

Prophylactic Inferior Vena Cava Filters : Outcomes in Severely Injured Trauma Patients

BACKGROUND

Patients with major trauma and contraindications to anticoagulation are often considered candidates for a prophylactic inferior vena cava filter (IVCF). Prophylactic IVCFs are controversial in trauma and backed by varying levels of evidence. This study aims to analyze outcomes in severely injured patients who receive IVCFs.

METHODS

A retrospective review of trauma patients aged ≥ 16 years with ISS ≥ 15 admitted to our level 1 trauma center from years 2013 through 2018. Patients were divided into 2 groups: prophylactic IVCF versus VTE chemoprophylaxis. The analysis evaluated demographics, stratified by ISS (15-24, 25-34, ≥35), and subgrouped those with AIS-Head ≥3. Adjusted outcome measures included DVT, PE, mortality, and ICU length-of-stay (ICU-LOS).

RESULTS

The study sample included 413 patients with prophylactic IVCFs and 2487 on VTE chemoprophylaxis. IVCF placement was associated with higher severity injuries: ISS 28 versus 25 and lower GCS 10.0 versus 11.8, TBI prevalence 83% versus 68% (P < .001). Patients with IVCFs had increased ICU-LOS (23.2 days vs 12.2 days), DVT (14.8% vs 4.3%), and PE (5.8% vs 1.6%) for patients with ISS <35 (P < .001). ISS ≥35 was not associated with intergroup DVT or PE rate differences (P = .81 and .43). No intergroup mortality differences were observed, including after ISS stratification. Among patients with AIS-Head ≥3, prophylactic IVCF was associated with lower in-hospital mortality (8.4% vs 15.7%, P = .001).

CONCLUSIONS

Prophylactic IVCF placement was associated with higher rates of DVT and nonfatal PE, and prolonged ICU-LOS. Prophylactic IVCF placement was not associated with increased in-hospital mortality for severely injured trauma patients. Among patients with concomitant critical head injuries (AIS-Head ≥3), prophylactic IVCF placement was associated with lower in-hospital mortality than VTE chemoprophylaxis.

Timing of Prophylactic Inferior Vena Cava Filter Placement and Trauma Outcomes : Does Early Placement Matter?

BACKGROUND

Prophylactic inferior vena cava filters (IVCFs) are often placed in trauma patients who cannot receive prophylactic anticoagulation. IVCFs are utilized in an effort to reduce the risk of acute pulmonary embolism (PE) and mortality. This study aims to investigate whether time-to-filter placement is associated with differences in trauma outcomes.

METHODS

We conducted a single-center retrospective review of adult trauma patients who underwent prophylactic IVCF placement. Patients were divided into 2 groups based on time-to-filter: 0-48 hours and >48 hours. Outcome measures included post-filter deep vein thrombosis (DVT), post-filter PE, in-hospital mortality, and ICU length of stay (ICU-LOS). Significance was defined as P < .05.

RESULTS

During the 6-year study period, 513 patients underwent prophylactic IVCF placement. Both groups were similar with respect to injury severity score (ISS) (P = .540), percent of patients on home anticoagulation (38% and 39%, P = .845), abbreviated injury scale (AIS) by anatomic region (P = .899), and traumatic brain injury (TBI) prevalence (P = .182). Time-to-filter was not associated with significant differences in DVT, PE, or in-hospital mortality (P > .05 for all). Filter placement in the first 48 hours was associated with shorter ICU-LOS and hospital-LOS.

CONCLUSIONS

Currently, there are no investigations in the trauma literature looking at the impact of time-to-filter on complications related to venous thromboembolism and potential survival benefit. Results of this investigation showed that IVCF placement within the first 48 hours was significantly associated with shorter ICU- and hospital- LOS.

Long-term complications of inferior vena cava filters

Anticoagulation is the cornerstone for the treatment of deep venous thrombosis and pulmonary embolism. On occasion, this is not possible because of bleeding complications or, rarely, breakthrough pulmonary embolism associated with this treatment method. The development of vena cava interruption in the 1970s was a critical advance in the treatment of these patients. Placement of inferior vena cava (IVC) filters has been steadily increasing since their introduction. Nonetheless, the incidence of complications associated with placement of these devices is largely unknown. Most of the evidence regarding IVC filter complications relies on case reports, with scarce data coming from larger randomized controlled trials. We aimed to present a summary addressing long-term complications of IVC filters as published in recent articles addressing problems such as IVC thrombosis and IVC filter migration, perforation, fracture, embolization, and tilting. We performed a PubMed search and Google Scholar search using different combinations of "long term," "complications," "IVC filter," and "vena cava filter." We reviewed the available English publications and reported the findings in this summary.

Vena Cava Filters: A Synopsis of Complications and Related Topics

Deep venous thrombosis and pulmonary embolism constitute common preventable causes of morbidity and mortality. The incidence of venous thromboembolism (VTE) continues to increase. Standard anticoagulation therapy may reduce the risk of fatal PE by 75% and that of recurrent VTE by over 90%. For patients who are not candidates for anticoagulation, a vena cava filter (VCF) may be beneficial. Despite a good overall safety record, significant complications related to VCF are occasionally seen. This review discusses both procedural and non-procedural complications associated with VCF placement and use. We will also discuss VCF use in the settings of pregnancy, malignancy, and the clinical need for more than one filter.

Inferior Vena Cava Filters: Current and Future Concepts

The inferior vena cava filter clinical environment is notable for the degree of controversy, uncertainty, and fear associated with these devices by both physicians and the public. This article reviews some of the more important current issues with these devices as well as emerging and future trends.

Detailed assessment of benefits and risks of retrievable inferior vena cava filters on patients with complicated injuries: the da Vinci multicentre randomised controlled trial study protocol

INTRODUCTION

Retrievable inferior vena cava (IVC) filters have been increasingly used in patients with major trauma who have contraindications to anticoagulant prophylaxis as a primary prophylactic measure against venous thromboembolism (VTE). The benefits, risks and cost-effectiveness of such strategy are uncertain.

METHODS AND ANALYSIS

Patients with major trauma, defined by an estimated Injury Severity Score >15, who have contraindications to anticoagulant VTE prophylaxis within 72 hours of hospitalisation to the study centre will be eligible for this randomised multicentre controlled trial. After obtaining consent from patients, or the persons responsible for the patients, study patients are randomly allocated to either control or IVC filter, within 72 hours of trauma admission, in a 1:1 ratio by permuted blocks stratified by study centre. The primary outcomes are (1) the composite endpoint of (A) pulmonary embolism (PE) as demonstrated by CT pulmonary angiography, high probability ventilation/perfusion scan, transoesophageal echocardiography (by showing clots within pulmonary arterial trunk), pulmonary angiography or postmortem examination during the same hospitalisation or 90-day after trauma whichever is earlier and (B) hospital mortality; and (2) the total cost of treatment including the costs of an IVC filter, total number of CT and ultrasound scans required, length of intensive care unit and hospital stay, procedures and drugs required to treat PE or complications related to the IVC filters. The study started in June 2015 and the final enrolment target is 240 patients. No interim analysis is planned; incidence of fatal PE is used as safety stopping rule for the trial.

ETHICS AND DISSEMINATION

Ethics approval was obtained in all four participating centres in Australia. Results of the main trial and each of the secondary endpoints will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

ACTRN12614000963628; Pre-results.

Complications of inferior vena cava filters

Inferior vena cava (IVC) filter placement is a relatively low risk alternative for prophylaxis against pulmonary embolism in patients with pelvic or lower extremity deep venous thrombosis who are not suitable for anticoagulation. There is an increasing trend in the number of IVC filter implantation procedures performed every year. There are many device types in the market and in the early 2000s, the introduction of retrievable filters brought an additional subset of complications to consider. Modern filter designs have led to decreased morbidity and mortality, however, a thorough understanding of the limitations and complications of IVC filters is necessary to weight the risks and benefits of placing IVC filters. In this review, the complications associated with IVC filters are divided into procedure related, post-procedure, and retrieval complications. Differences amongst the device types and retrievable filters are described, though this is limited by a significant lack of prospective studies. Additionally, the clinical presentation as well as prevention and treatment strategies are outlined with each complication type.

Vena Caval Filters: A Review for Intensive Care Specialists

Venous thromboembolism (VTE) is a common complication among patients in the intensive care unit. While anticoagulation remains standard therapy, vena caval filters are an important alternative when anticoagulation is contraindicated. To determine the safety and efficacy of vena caval filters in the treatment of VTE, a comprehensive review of the English-language medical literature was performed. Except for one randomized controlled trial, the literature supporting the use of vena caval filters consists almost exclusively of case series, which in many instances are limited by incomplete and short follow-up. While case series suggest that filters function effectively in the prevention of pulmonary embolism (2%-4% symptomatic pulmonary embolism [PE], fatal PE < 2%), recent higher quality studies indicate that filters may not provide significant additional protection to that provided by anticoagulation alone. Furthermore, filters are associated with a 2- fold increase in the incidence of recurrent DVT. Until randomized comparative studies are available, the safety and efficacy of all the available devices should be considered to be roughly equivalent. Since filters do not inhibit continued clot formation, all filter patients should receive anticoagulation for durations appropriate for their thrombotic disorder. Although extended anticoagulation may prevent thrombotic complications associated with filter placement, this strategy has yet to be experimentally tested. While many additional indications for vena caval filter use have been proposed (VTE in cancer patients, PE prophylaxis in trauma patients, etc), well-designed clinical trials demonstrating their efficacy in these situations are lacking. Further development of temporary/retrievable filters, which offer the potential to avoid the long-term complications of permanent filters, should be a research priority. Until additional data are available, vena caval filters should generally be restricted to patients with VTE who cannot receive anticoagulation.

Pharmacologic venous thromboembolism prophylaxis after traumatic brain injury: a critical literature review

Despite the frequency and morbidity of venous thromboembolism (VTE) development after traumatic brain injury (TBI), no national standard of care exists to guide TBI caregivers for the use of prophylactic anticoagulation. Fears of iatrogenic propagation of intracranial hemorrhage patterns have led to a dearth of research in this field, and it is only relatively recently that studies dedicated to this question have been performed. These have generally been limited to retrospective and/or observational studies in which patients are classified in a binary fashion as having the presence or absence of intracranial blood. This methodology does not account for the fact that smaller injury patterns stabilize more rapidly, and thus may be able to safely tolerate earlier initiation of prophylactic anticoagulation than larger injury patterns. This review seeks to critically assess the literature on this question by examining the existing evidence on the safety and efficacy of pharmacologic VTE prophylaxis in the setting of elective craniotomy (as this is the closest model available from which to extrapolate) and after TBI. In doing so, we critique studies that approach TBI as a homogenous or a heterogenous study population. Finally, we propose our own theoretical protocol which stratifies patients into low, moderate, and high risk for the likelihood of natural progression of their hemorrhage pattern, and which allows one to tailor a unique VTE prophylaxis regimen to each individual arm.

Vena cava filter practices of a regional vascular surgery society

BACKGROUND

Vena cava filter (VCF) use in the United States has increased dramatically with prophylactic indications for placement and the availability of low-profile retrievable devices, which are overtaking the filter market. We surveyed the practice patterns of a large group of vascular surgeons from a regional vascular surgery society to see whether they mirrored current national trends.

METHODS

A 17-question online VCF survey was offered to all members of the Southern Association of Vascular Surgery. The responses were analyzed using the χ(2) goodness of fit tests.

RESULTS

Of the 276 members surveyed, 126 (46%) responded, with 118 (93%) indicating that they placed filters during their practice. Highly significant differences were identified with each question (at least P < 0.002). Regarding the inferior vena cava, the preferred permanent filters were the Greenfield (31%), the TrapEase (15%), the Vena Tech (5%), and a variety of retrievable devices (49%). Fifty percent of the respondents placed retrievable filters selectively; 26% always placed them; and 24% never did. Filters were placed for prophylactic indications <50% of the time by 63% of the respondents. Overall, retrievable filters (when not used as permanent filters) were removed <25% of the time by 64% of the respondents and <50% of the time by 78% of the respondents. The femoral vein was the preferred access site for 84% of the respondents. Major complications were few but included filter migration to the atrium (one), atrial perforation (one), abdominal pain requiring surgical filter removal (two), inferior vena cava thrombosis (12 vena cava thrombosis--4 due to TrapEase filters), strut fracture with embolization to heart or lungs (three Bard retrievable filters), and severe tilting precluding percutaneous retrieval and protection from pulmonary emboli (8 filters with severe tilt--7 of which were Bard). Of the respondents, 59% had never placed a superior vena cava filter, and 28% had placed five or fewer.

CONCLUSIONS

Although VCF insertion overall appears safe, some complications are specific to biconical and certain retrievable filters. Given the low removal rate and lack of long-term experience with retrievable filters, routine use of these devices as permanent filters should be questioned. If used on a temporary basis, there should be a plan for filter removal at the time of implantation.

Payer status is associated with the use of prophylactic inferior vena cava filter in high-risk trauma patients

BACKGROUND

It is controversial whether patients at high risk for pulmonary embolism (PE) should receive prophylactic inferior vena cava filters (IVC) filters. This lack of clarity creates the potential for variability and disparities in care. We hypothesized there would be differential use of prophylactic IVC filters for patients at high risk for PE on the basis of insurance status.

METHODS

We performed a retrospective analysis using the National Trauma Databank (2002-2007). We included adult patients at high risk for PE (traumatic brain injury or spinal cord injury) and excluded patients with a diagnosis of deep venous thrombosis (DVT) or PE. Logistic regression was performed to control for confounders and a hierarchical mixed effects model was used to control for center.

RESULTS

A prophylactic filter was placed in 3,331 (4.3%) patients in the study cohort. Patients without insurance had an IVC filter placed less often compared with those with any form of insurance (2.7% vs 4.9%, respectively). After adjusting for confounders, we found that patients without insurance were less likely to receive a prophylactic IVC filter, even when we controlled for center (OR 5.3, P < .001).

CONCLUSION

When guidelines lack clarity, unconscious bias has the potential to create a system with different levels of care based on socioeconomic disparities.

The use of retrievable inferior vena cava filters in the trauma population

OBJECTIVE

To determine if the use of retrievable filters resulted in an increase in the placement of inferior vena cava (IVC) filters in trauma patients.

DESIGN

All patients who underwent IVC filter placement at Yale-New Haven Hospital, New Haven, Connecticut, USA between the years 1999 and 2004.

SETTING

Academic, level 1 trauma centre.

PATIENTS

Included in the present study were 202 trauma patients and 676 nontrauma patients.

INTERVENTION

IVC filter placement.

MAIN OUTCOME MEASURE

Demographics, indications, complication rates and type of IVC filters placed in trauma patients versus nontrauma patients were evaluated.

RESULTS

The present study determined 45.4% (n=92) of trauma patients undergoing IVC filter placement were younger than 40 years of age, compared with 7.8% (n=53) of nontrauma patients. The most common indication for IVC filter placement in trauma patients was prophylaxis (n=162, 80.2%), while in the nontrauma patients only 11.4% (n=77) of patients underwent prophylactic filter placement. The number of retrievable filters used in trauma patients increased from 46.7% in 2001, the year they became available, to 78.9% in 2004. The use of retrievable filters similarly increased in the nontrauma population from 35.9% in 2001 to 78.3% in 2004. Approximately 24% of the patients that underwent IVC filter placement at Yale-New Haven Hospital were categorized as trauma patients. The complication rate for this time period was 0.5% (n=1) in the trauma population versus 3.7% (n=26) in the nontrauma population.

CONCLUSION

The overall number of IVC filters placed in trauma patients did not dramatically increase with the introduction of retrievable filters, suggesting that the indications for the use of IVC filters have not changed.

The use of prophylactic inferior vena cava filters in trauma patients: a systematic review

INTRODUCTION

Pulmonary embolisms (PE) are an often preventable cause of late morbidity and mortality after trauma. Although there is evidence for the use of therapeutic inferior vena cava (IVC) filters (defined as IVC filters implanted in those with proven deep venous thrombosis [DVT] in order to prevent PE), there is not as much evidence to support the use of prophylactic IVC filters. Thus, we undertook a systematic review of the literature to assess the following in prophylactic IVC filters: efficacy in PE reduction, prevalence of filter-related complications and the indications for use.

MATERIALS AND METHODS

After screening 249 studies, 24 studies met inclusion criteria for qualitative synthesis.

RESULTS

Overall, the literature is supportive of the use of prophylactic IVC filters in high-risk poly-trauma patients who may have contraindications to DVT prophylaxis. Filter-associated complications are uncommon and, when they do occur, tend to be of limited clinical significance. Limited data, mostly in the form of case series, supports a reduction in PE and PE-related mortality. There has been increasing use of retrievable filters as well as the ability to safely retrieve them at longer intervals.

CONCLUSION

Despite the addition of a few matched-control studies, the literature is still plagued by a lack of high quality data, and therefore the true efficacy of prophylactic IVC filters for prevention of PE in trauma patients remains unclear. Further studies are required to determine the true role of prophylactic IVC filters in trauma patient.

Vena cava interruption

Anticoagulation has been proven to be effective in preventing and treating deep vein thrombosis and pulmonary embolus. However, many critically ill patients are unable to receive anticoagulation or suffer recurrent venous thromboembolism despite adequate treatment. This article examines the use of vena cava filters in the critically ill. Indications for, techniques, and complications of vena cava filter insertion are reviewed. The importance of vena cava filters with the option to be retrieved and bedside insertion in the intensive care unit is emphasized.

Optional inferior vena cava filters in the trauma patient

Trauma patients are at exceedingly high risk of development of venous thromboembolism (VTE) including deep venous thrombosis and pulmonary embolism (PE). The epidemiology of VTE in trauma patients is reviewed. PE is thought to be the third major cause of death after trauma in those patients who survive longer than 24 hours after onset of injury. In fact, patients recovering from trauma have the highest rate of VTE among all subgroups of hospitalized patients. Various prophylactic and surveillance methods have been evaluated and found helpful in certain situations, but VTE complications can occur despite such measures. Therapeutic and prophylactic uses of inferior vena cava (IVC) filters in trauma patients are reviewed. Prophylactic IVC filter use is revealed to be a controversial subject with valid arguments on both sides of the issue. With the lack of prospective randomized trials of IVC filter use in trauma, it is impossible to make evidence-based recommendations. Unfortunately, two sets of guidelines are available for insertion of filters in trauma patients, with conflicting recommendations. The introduction of retrievable IVC filters seems to offer a unique solution for VTE protection in the trauma patient population, which often consists of younger members of our population. Lastly, current generations of FDA-approved retrieval filters are discussed.

The Transition to IVUS-Guided IVC Filter Deployment in the Nontrauma Patient

While prior reports have demonstrated intravascular ultrasound (IVUS)-guided inferior vena cava filter (IVCF) deployment to be feasible, larger reviews using the latest generation of filters in the nontrauma setting are absent. We review our experience with the deployment of 104 IVCFs using IVUS, whereby we transition from a combined use of IVUS with traditional road mapping techniques (venography and/or renal vein cannulation) to the sole use of the IVUS as the road mapping tool for IVCF insertion. The use of IVUS for IVCF deployment minimizes radiation exposure to patients and staff, minimizes patient contrast exposure, and minimizes dependency on auxiliary staff for fluoroscopy. Intravascular ultrasound IVCF deployments can be performed without increasing morbidity and mortality, case duration, or overall costs when compared to standard deployments. The learning curve for transitioning into the use of the IVUS as the primary road mapping tool for IVCF deployments is approximately 20 cases.

Incidence and risk factors for fatal pulmonary embolism after major trauma: a nested cohort study

BACKGROUND

Venous thromboembolism is common after major trauma. Strategies to prevent fatal pulmonary embolism (PE) are widely utilized, but the incidence and risk factors for fatal PE are poorly understood.

METHODS

Using linked data from the intensive care unit, trauma registry, Western Australian Death Registry, and post-mortem reports, the incidence and risk factors for fatal PE in a consecutive cohort of major trauma patients, admitted between 1994 and 2002, were assessed. Non-linear relationships between continuous predictors and risk of fatal PE were modelled by logistic regression.

RESULTS

Of the 971 consecutive trauma patients considered in the study, 134 (13.8%) died after their injuries. Fatal PE accounted for 11.9% of all deaths despite unfractionated heparin prophylaxis being used in 44% of these patients. Fatal PE occurred in those who were older (mean age 51- vs 37-yr-old, P=0.01), with more co-morbidities (Charlson's co-morbidity index 1.1 vs 0.2, P=0.01), had a larger BMI (31.8 vs 24.5, P=0.01), and less severe head and systemic injuries when compared with those who died of other causes. Sites of injuries were not significantly related to the risk of fatal PE. Fatal PE occurred much later than deaths from other causes (median 18 vs 2 days, P=0.01), and the estimated attributable mortality of PE was 49% (95% confidence interval 36-62%).

CONCLUSIONS

Fatal PE appeared to be a potential preventable cause of late mortality after major trauma. Severity of injuries, co-morbidity, and BMI were important risk factors for fatal PE after major trauma.

Cost-effectiveness of guidelines for insertion of inferior vena cava filters in high-risk trauma patients

BACKGROUND

Inferior vena cava filters (IVCFs) can prevent pulmonary embolism (PE); however, indications for use vary. The Eastern Association for the Surgery of Trauma (EAST) 2002 guidelines suggest prophylactic IVCF use in high-risk patients, but the American College of Chest Physicians (ACCP) 2008 guidelines do not. This analysis compares cost-effectiveness of prophylactic vs therapeutic retrievable IVCF placement in high-risk trauma patients.

METHODS

Markov modeling was used to determine incremental cost-effectiveness of these guidelines in dollars per quality-adjusted life-years (QALYs) during hospitalization and long-term follow-up. Our population was 46-year-old trauma patients at high risk for venous thromboembolism (VTE) by EAST criteria to whom either the EAST (prophylactic IVCF) or ACCP (no prophylactic IVCF) guidelines were applied. The analysis assumed the societal perspective over a lifetime. For base case and sensitivity analyses, probabilities and utilities were obtained from published literature and costs calculated from Centers for Medicare & Medicaid Services fee schedules, the Healthcare Cost & Utilization Project database, and Red Book wholesale drug prices for 2007. For data unavailable from the literature, similarities to other populations were used to make assumptions.

RESULTS

In base case analysis, prophylactic IVCFs were more costly ($37,700 vs $37,300) and less effective (by 0.139 QALYs) than therapeutic IVCFs. In sensitivity analysis, the EAST strategy of prophylactic filter placement would become the preferred strategy in individuals never having a filter, with either an annual probability of VTE of ≥ 9.6% (base case, 5.9%), or a very high annual probability of anticoagulation complications of ≥ 24.3% (base case, 2.5%). The EAST strategy would also be favored if the annual probability of venous insufficiency was <7.69% (base case, 13.9%) after filter removal or <1.90% with a retained filter (base case, 14.1%). In initial hospitalization only, EAST guidelines were more costly by $2988 and slightly more effective by .0008 QALY, resulting in an incremental cost-effectiveness ratio of $383,638/QALY.

CONCLUSIONS

Analysis suggests prophylactic IVC filters are not cost-effective in high-risk trauma patients. The magnitude of this result is primarily dependent on probabilities of long-term sequelae (venous thromboembolism, bleeding complications). Even in the initial hospitalization, however, prophylactic IVCF costs for the additional quality-adjusted life years gained did not justify use.

Vena Cava Filter Insertion and the General Surgery Armamentarium: A 13-Year Experience

The prevention of pulmonary emboli has a long surgical history. Through the development of percutaneous technologies, vena cava filters (VCFs) are now commonly inserted by interventional radiologists. This study reviews our experience with VCFs inserted by general surgeons. We retrospectively reviewed data from our VCF performance improvement database, which is a prospective collection of the VCF experience of the Department of General Surgery from February 1996 to May 2009. Demographics, procedural information, and complications were recorded. Eight hundred fifty-five VCFs were inserted in 853 patients. The mean age was 42.0 years (range, 14 to 90 years). One hundred ninety-seven VCFs were placed in the operating room, and 658 were placed in the intensive care unit. Twelve VCFs were intentionally inserted in a suprarenal position, and four were placed in the superior vena cava. Two patients received both superior vena cava and inferior vena cava filters. Complications included deep vein thrombosis at the insertion site (n = 16), vena cava thrombosis (n = 9), post-VCF pulmonary embolism (n = 2), and a ventricle perforation requiring operative repair (n = 1). No deaths were attributed to the presence of a VCF. Overall insertion success was 99.8 per cent. In two patients, an inferior VCF could not be placed as a result of inferior vena cava occlusion with no safe “landing zone” for deployment. The placement of VCFs is a vital skill in the general surgery armamentarium. Our experience demonstrates that general surgeons can safely insert VCFs with minimal perioperative complications.

Complications related to deep venous thrombosis prophylaxis in trauma: a systematic review of the literature

Deep venous thrombosis prophylaxis is essential to the appropriate management of multisystem trauma patients. Without thromboprophylaxis, the rate of venous thrombosis and subsequent pulmonary embolism is substantial. Three prophylactic modalities are common: pharmacologic anticoagulation, mechanical compression devices, and inferior vena cava filtration. A systematic review was completed using PRISMA guidelines to evaluate the potential complications of DVT prophylactic options. Level one evidence currently supports the use of low molecular weight heparins for thromboprophylaxis in the trauma patient. Unfortunately, multiple techniques are not infrequently required for complex multisystem trauma patients. Each modality has potential complications. The risks of heparin include bleeding and heparin induced thrombocytopenia. Mechanical compression devices can result in local soft tissue injury, bleeding and patient non-compliance. Inferior vena cava filters migrate, cause inferior vena cava occlusion, and penetrate the vessel wall. While the use of these techniques can be life saving, they must be appropriately utilized.

Long-term follow-up of trauma patients with permanent prophylactic vena cava filters

BACKGROUND

Although permanent prophylactic Greenfield filters (PPGF) are effective, their use in young trauma patients who may eventually return to active lifestyles is controversial due to concerns about the safety of the devices over a lifetime. This descriptive study was undertaken to provide follow-up on the long-term safety and durability of PPGF.

METHODS

All patients receiving a PPGF between April 1, 1992 and March 1, 2001 were sought for follow-up. Contacted patients were interviewed regarding known filter-related complications, venous thromboembolic events, and activity levels since the time of discharge from the hospital. Patients were also offered a physical examination focusing on venous thromboembolic sequelae, a plain film of the abdomen (KUB) to assess filter integrity and location, and an ultrasound to assess caval patency. As the original level of filter placement was usually not known, migration was defined as a filter above the first lumbar vertebra (L1).

RESULTS

The eligible cohort consisted of 188 patients. Ninety were unable to be located (47.8%), one refused enrollment (0.5%), and 97 patients or next of kin agreed to be interviewed by phone (51.6%) of whom 69 returned for evaluation (36.7%). No filter-related complications were self-reported. KUBs were performed in 68 patients; one filter strut fracture was found (1.5%), whereas no filter migrations above L1 were noted. No instances of caval thrombosis were found in 55 ultrasounds. Two patients suffered interim pulmonary emboli (2.1%), one of which was fatal. Of 15 interim deaths, autopsy or death certificates were available for four patients, nine had their causes of death related by next of kin, and two were unknown. Although 95.4% of nonspinal cord injury patients reported at least some ability to ambulate, only 64.6% could do so ad libitum. Of those patients ambulating without limitation, 28.6% reported a complete inability to run any distance and another 23.8% could run less than one block. Follow-up for patients completing interviews was 105.3 months +/- 18.0 months, and for patients undergoing imaging was 104.6 months +/- 16.4 months. Interim deaths occurred at 48.2 months +/- 26.0 months.

CONCLUSIONS

PPGF seem to be safe and effective at 105 months of follow-up; most patients report significant limitations in activity level at this same timeframe. PPGF should be the filter of choice for elderly patients in whom this time period can reasonably be expected to cover the patient's remaining life expectancy.

An economic evaluation of venous thromboembolism prophylaxis strategies in critically ill trauma patients at risk of bleeding

BACKGROUND

Critically ill trauma patients with severe injuries are at high risk for venous thromboembolism (VTE) and bleeding simultaneously. Currently, the optimal VTE prophylaxis strategy is unknown for trauma patients with a contraindication to pharmacological prophylaxis because of a risk of bleeding.

METHODS AND FINDINGS

Using decision analysis, we estimated the cost effectiveness of three VTE prophylaxis strategies-pneumatic compression devices (PCDs) and expectant management alone, serial Doppler ultrasound (SDU) screening, and prophylactic insertion of a vena cava filter (VCF) -- in trauma patients admitted to an intensive care unit (ICU) with severe injuries who were believed to have a contraindication to pharmacological prophylaxis for up to two weeks because of a risk of major bleeding. Data on the probability of deep vein thrombosis (DVT) and pulmonary embolism (PE), and on the effectiveness of the prophylactic strategies, were taken from observational and randomized controlled studies. The probabilities of in-hospital death, ICU and hospital discharge rates, and resource use were taken from a population-based cohort of trauma patients with severe injuries (injury severity scores >12) admitted to the ICU of a regional trauma centre. The incidence of DVT at 12 weeks was similar for the PCD (14.9%) and SDU (15.0%) strategies, but higher for the VCF (25.7%) strategy. Conversely, the incidence of PE at 12 weeks was highest in the PCD strategy (2.9%), followed by the SDU (1.5%) and VCF (0.3%) strategies. Expected mortality and quality-adjusted life years were nearly identical for all three management strategies. Expected health care costs at 12 weeks were Can$55,831 for the PCD strategy, Can$55,334 for the SDU screening strategy, and Can$57,377 for the VCF strategy, with similar trends noted over a lifetime analysis.

CONCLUSIONS

The attributable mortality due to PE in trauma patients with severe injuries is low relative to other causes of mortality. Prophylactic placement of VCF in patients at high risk of VTE who cannot receive pharmacological prophylaxis is expensive and associated with an increased risk of DVT. Compared to the other strategies, SDU screening was associated with better clinical outcomes and lower costs.

Bedside placement of removable vena cava filters guided by intravascular ultrasound in the critically injured

BACKGROUND

Bedside placement of removable inferior vena cava filters (RVCF) is increasingly used in critically injured patients. The need for fluoroscopic equipment and specialized intensive care unit beds presents major challenges. Intravascular ultrasound (IVUS) eliminates such problems. The objective of the present study was to analyze the safety and feasibility of IVUS-guided bedside RVCF placement in critically injured patients.

METHODS

Between October 2004 and July 2006 47 IVUS-guided RVCF were placed at the bedside. Medical and trauma registry records were reviewed. Primary outcome was RVCF-related complications.

RESULTS

The mean patient age was 41 +/- 19 years, and the mean Injury Severity Score was 30 +/- 12. The right common femoral vein was chosen as the site of access in 40 patients, and the left common femoral vein was the access site in 7 patients. The insertion was performed 3.7 +/- 2.5 days after admission. Four patients (8.5%) developed common femoral deep vein thrombosis (DVT) and three (6%) developed a peripheral pulmonary embolism (PE). Complications related to technique were recorded in two patients (4%) and included one misplacement and one access site bleeding with no further associated morbidity. Five patients died during the hospital stay from issues unrelated to RVCF. Forty-one patients were eligible for follow-up. Removal of RVCF was offered only to 8 patients and was performed successfully in 4 (10%) at a mean of 130 days (range: 44-183 days).

CONCLUSIONS

In this study IVUS-guided bedside placement of RVCF was feasible but was also associated with complications. Follow-up was poor, and the rate of removal disappointingly low, underscoring the need for further exploration of the role of RVCF.

Experiência preliminar com novo filtro de veia cava: resultados de 15 implantes

Este estudo apresenta resultados preliminares obtidos com um novo filtro permanente de veia cava, baseado no desenho de Greenfield, com três hastes prolongadas de um total de seis, para dar estabilidade central ao filtro na luz da veia cava. Neste artigo, relatamos sua avaliação clínica preliminar quanto à aplicabilidade, eficácia e segurança. De agosto de 2004 a dezembro de 2006, 15 filtros foram implantados em nove homens e seis mulheres, com idades variando de 38 a 79 anos (média de 57,8 anos). O acesso foi feito sempre por via transjugular. As indicações foram: trombose venosa proximal, com contra-indicação de anticoagulação em 12 pacientes; complicações hemorrágicas com anticoagulação em dois pacientes; e embolia pulmonar, apesar de anticoagulação adequada, em um paciente. Os filtros foram avaliados quanto à liberação, inclinação, mau posicionamento e perfuração de cava. No seguimento, avaliou-se trombose no local de acesso, tromboembolismo venoso recorrente, migração do filtro e trombose de cava pelo ultra-som. Nenhum paciente recebeu anticoagulantes no seguimento. O filtro foi liberado com sucesso em todos os casos sem mau posicionamento, inclinação, perfuração ou trombose de acesso. Os pacientes foram seguidos entre 3 e 23 meses (média de 11 meses). Nenhum paciente teve recorrência de tromboembolismo venoso. Não houve casos de trombose de veia cava ou migração do filtro. Óbito ocorreu em sete casos, todos relacionados com a moléstia de base. Os resultados preliminares indicam potencial eficácia e segurança do uso do novo filtro no período estudado.

Inferior vena cava filters and lower limb flap reconstructions

BACKGROUND

This is the first ever study looking at the combination of inferior vena cava (IVC) filters and flap reconstruction in traumatic lower limb injuries. The use of IVC filters is increasing and they are now being used prophylactically in trauma patients who are at a high risk of developing thromboembolism disease. Although it has been postulated that IVC filters, through its positioning in the IVC, results in a higher incidence of venous congestion and possibly failure of lower limb flaps, the effect of IVC filters on lower limb flap reconstructions has not been addressed in the published works. The aim of this study was to determine whether IVC filters affect the outcome of lower limb flap reconstructions in the trauma patient.

METHODS

Retrospective case series analysis of consecutive patients at the Alfred Hospital (Melbourne, Australia) who had lower limb flap reconstruction(s) and IVC filter placement from 1 July 2001 to 22 March 2005 (44-month period).

RESULTS

Seventeen patients (12 men and 5 women) had 23 lower limb flap reconstructions (10 free, 13 local flaps) and IVC filter insertion. All 23 flaps survived with no flap failures. A gracilis muscle free flap developed venous congestion but survived with conservative management.

CONCLUSIONS

In our series, IVC filters were not associated with poor outcomes of lower limb flap reconstructions. These findings are encouraging, and based on the evidence to date, the presence of IVC filters should not deter lower limb flap reconstructions in trauma patients. In particular, free flap surgery to traumatized lower limbs is not an issue with patients who have IVC filters.

Analysis of tilt of the Günther Tulip filter

PURPOSE

To determine the frequency, dimensions, predictors, and sequelae of Günther Tulip filter (GTF) tilt measured at the time of intended retrieval.

MATERIALS AND METHODS

Retrospective review of all medical records and posteroanterior cavograms of 175 patients who underwent both placement and retrieval of the GTF between August 2003 and July 2007 was performed to assess the frequency, dimensions, predictors, and sequelae of tilt.

RESULTS

Tilt occurred at the first retrieval attempt in 159 of the 175 patients (91%). The average degree of tilt was 7.1 degrees (range, 0 degrees-30 degrees), with 87 of the 159 filters with tilt (55%) having a rightward tilt. Compared with the femoral approach, filters placed with a jugular approach demonstrated 4.2 degrees (range of the standard deviation, 3.1 degrees-5.3 degrees) greater tilt at the first retrieval attempt (95% confidence interval=2.6 degrees, 5.7 degrees; P<.001, two-sided Student t test), a greater frequency of tilt of at least 14 degrees (P=.002, two-sided Fisher exact test), and greater rightward tilt predominance (P=.046, one-sided Fisher exact test). Tilt magnitude at the first retrieval attempt correlated positively with the inferior vena cava diameter 40 mm caudal to the renal vein confluence (R=.183, P=.018, Pearson correlation). Within its limitations, this study detected no new cases of pulmonary embolism, caval perforation, or GTF migration. The success rates at the first attempt at retrieval and the cumulative GTF retrieval success rates were 93% (176 of 190 filters) and 97% (181 of 190 filters), respectively. All 29 GTFs with tilt of at least 14 degrees were placed and successfully retrieved by means of a jugular approach with minimal clinical and technical sequelae.

CONCLUSIONS

Frequent GTF tilt detected at the first retrieval attempt can reach at least 14 degrees and is associated with minimal sequelae. Insertion approach and caval diameter are significant factors in GTF tilt.