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Original Investigation |

The Effectiveness of Prophylactic Inferior Vena Cava Filters in Trauma Patients:  A Systematic Review and Meta-analysis FREE

Elliott R. Haut, MD1,2,3,4; Luis J. Garcia, MD1; Hasan M. Shihab, MBChB, MPH5; Daniel J. Brotman, MD6; Kent A. Stevens, MD, MPH1; Ritu Sharma, BSc5; Yohalakshmi Chelladurai, MBBS, MPH5; Tokunbo O. Akande, MBBS, MPH5; Kenneth M. Shermock, PharmD, PhD4,7; Sosena Kebede, MD, MPH6; Jodi B. Segal, MD, MPH5,6; Sonal Singh, MD, MPH5,6
[+] Author Affiliations
1Division of Acute Care Surgery, Department of Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland
2Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland
3Department of Emergency Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland
4Armstrong Institute for Patient Safety and Quality, The Johns Hopkins Medical Institutions, Baltimore, Maryland
5The Johns Hopkins Evidence-Based Practice Center, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland
6Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland
7Center for Pharmaceutical Outcomes, The Johns Hopkins Hospital, Baltimore, Maryland
JAMA Surg. 2014;149(2):194-202. doi:10.1001/jamasurg.2013.3970.
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Importance  Trauma is known to be one of the strongest risk factors for pulmonary embolism (PE). Current guidelines recommend low-molecular-weight heparin therapy for prevention of PE, but trauma places some patients at risk of excess bleeding. Experts are divided on the role of prophylactic inferior vena cava (IVC) filters to prevent PE.

Objective  To perform a systematic review and meta-analysis examining the comparative effectiveness of prophylactic IVC filters in trauma patients, particularly in preventing PE, fatal PE, and mortality.

Data Sources  We searched the following databases for primary studies: MEDLINE, EMBASE, Scopus, CINAHL, International Pharmaceutical Abstracts, clinicaltrial.gov, and the Cochrane Library (all through July 31, 2012). We developed a search strategy using medical subject headings terms and text words of key articles that we identified a priori. We reviewed the references of all included articles, relevant review articles, and related systematic reviews to identify articles the database searches might have missed.

Study Selection  We reviewed titles followed by abstracts to identify randomized clinical trials or observational studies with comparison groups reporting on the effectiveness and/or safety of IVC filters for prevention of venous thromboembolism in trauma patients.

Data Extraction and Synthesis  Two investigators independently reviewed abstracts and abstracted data. For studies amenable to pooling with meta-analysis, we pooled using the random-effects model to analyze the relative risks. We graded the quantity, quality, and consistency of the evidence by adapting an evidence-grading scheme recommended by the Agency for Healthcare Research and Quality.

Results  Eight controlled studies compared the effectiveness of no IVC filter vs IVC filter on PE, fatal PE, deep vein thrombosis, and/or mortality in trauma patients. Evidence showed a consistent reduction of PE (relative risk, 0.20 [95% CI, 0.06-0.70]; I2 = 0%) and fatal PE (0.09 [0.01-0.81]; I2 = 0%) with IVC filter placement, without any statistical heterogeneity. We found no significant difference in the incidence of deep vein thrombosis (relative risk, 1.76 [95% CI, 0.50-6.19]; P = .38; I2 = 56.8%) or mortality (0.70 [0.40-1.23]; I2 = 6.7%). The number needed to treat to prevent 1 additional PE with IVC filters is estimated to range from 109 (95% CI, 93-190) to 962 (819-2565), depending on the baseline PE risk.

Conclusions and Relevance  The strength of evidence is low but supports the association of IVC filter placement with a lower incidence of PE and fatal PE in trauma patients. Which patients experience benefit enough to outweigh the harms associated with IVC filter placement remains unclear. Additional well-designed observational or prospective cohort studies may be informative.

Figures in this Article

Venous thromboembolism (VTE), including pulmonary embolism (PE) and deep vein thrombosis (DVT), affects as many as 600 000 Americans, killing more than 100 000 people each year and resulting in significant morbidity and mortality.1 Trauma is known to be one of the strongest risk factors for VTE. A prospective study2 reported rates of DVT as high as 58% among those who experience severe trauma without thromboprophylaxis, although other registry-based studies3,4 have reported lower rates. Guidelines recommend VTE prophylaxis with low-molecular-weight heparin in trauma.5,6

However, a small proportion of patients who are at the highest risk of VTE owing to severe injury also have definite or relative contraindications to low-molecular-weight heparin therapy because of an ongoing risk of life-threatening bleeding. In certain patients with traumatic brain injury, solid-organ injury (ie, liver, spleen), or retroperitoneal hematoma, the benefit of preventing VTE with low-molecular-weight heparin prophylaxis may be overshadowed by the risk of excess bleeding. In these cases, debate about the role of prophylactic inferior vena cava (IVC) filters to prevent PE is ongoing. Some authors7,8 suggest that using IVC filters among trauma patients at very high risk of PE may prevent the most dramatic and life-threatening cases. Other authors9 suggest their use is not beneficial and should be curtailed. Inferior vena cava filters are associated with risk of thrombotic complications (ie, caval thrombosis) and mechanical complications (ie, strut fracture, filter migration/embolization).

The increased use of IVC filters in general10 and in trauma patients specifically11 is well documented, with wide variation between trauma centers in the rates of IVC filter placement.12 This practice variation may result from conflicting guidelines. The Eastern Association for the Surgery of Trauma practice management guideline promotes IVC filters in certain patients.5 The American College of Chest Physicians has a more recent guideline stating that “for major trauma patients, we suggest that an IVC filter should not be used for primary VTE prevention.”6(p229S) For this systematic review and meta-analysis, we critically evaluated the data regarding the safety and efficacy of prophylactic IVC filters in trauma patients with the goal of providing evidence to guide practice and further research about their use.

We developed the protocol for the review and posted it online following guidelines for systematic reviews.13 Additional methodological details are in our evidence report prepared for the Agency for Healthcare Research and Quality (AHRQ).14 The full protocol was posted online (http://effectivehealthcare.ahrq.gov/index.cfm/search-for-guides-reviews-and-reports/). We developed an analytic framework that depicts our population of interest, interventions tested for VTE prevention, outcomes of treatment, and harms of interventions.14

Data Sources and Search

We searched the following databases for primary studies: MEDLINE, EMBASE, Scopus, CINAHL, International Pharmaceutical Abstracts, clinicaltrial.gov, and the Cochrane Library (through July 31, 2012). We developed a search strategy based on medical subject headings terms and text words of key articles that we identified a priori.15 We also reviewed the reference lists of all included articles, relevant review articles, and related systematic reviews.

Study Selection, Data Abstraction, and Quality Assessment

Two independent reviewers assessed the titles and then abstracts to identify randomized clinical trials (RCTs) or observational studies with comparison groups reporting on the effectiveness and/or safety of IVC filters for VTE prevention in trauma.14 We used a software program (DistillerSR; Evidence Partners, 2010) to manage the screening and review process. Paired reviewers used standardized forms for data extraction from the articles.

We conducted a risk-of-bias assessment (for the quality of evidence) independently and in duplicate using the Downs and Black instrument.16 We found that 10 items were most relevant to this review and prioritized them in our assessment of risk of bias. We considered studies to have a low risk of bias if the article completely described the hypothesis, outcomes (in the Introduction or Methods section), characteristics of the included subjects, distribution of the potential confounders in each group, interventions and comparisons (if relevant), main findings, adverse events, and characteristics of participants unavailable for or lost to follow-up. We also required low-risk studies to have randomized participants to the intervention, concealed the assignment or allocation of treatment until recruitment was complete, and masked the study participants and those measuring the main outcomes (double blinding). We rated studies as having a moderate risk of bias if 1 of those items was not true. If 2 of the elements were not true, we considered the study to have a high risk of bias.

Data Synthesis and Analysis

We created a detailed set of evidence tables containing all abstracted information. Meta-analysis was performed to pool results for the effect of IVC filter placement on each clinically important outcome (PE, fatal PE, DVT, and mortality). We considered the clinical and statistical heterogeneity of the studies. We identified substantial statistical heterogeneity in the trials as an I2 statistic greater than 50%.

We excluded studies from the meta-analysis if serious flaws, such as prognostic imbalance, were found in key confounders that were not accounted for in an unadjusted analysis. For studies amenable to pooling with meta-analysis, we pooled using a DerSimonian and Laird random-effects model17 as the primary analysis.

Most of the outcomes occurred at frequencies of less than 1%, and several studies had 0 events. Because the usual statistical approach of adding 0.5 to estimate the relative risk (RR) in the presence of 0 events may produce biased estimates, we used the treatment arm continuity correction approach to estimate the RR by adding a reciprocal of the treatment arm.18 We conducted a sensitivity analysis using alternative continuity corrections (0.5 and 0.01) and no continuity correction (Peto odds ratio).19 Combined estimates for the RR are presented along with a 95% confidence interval. Given the fragility of the data set, 2 independent experts, including one of us (S.S.) replicated the results in 2 different statistical programs. All analyses were conducted using StatsDirect20 and replicated in STATA, version 11.0.21

We calculated the number needed to treat (NNT) to prevent PE with IVC filters among trauma patients using an online calculator (http://www.nntonline.net). We used a range of possible baseline PE rates (0.13%-1.15%) from the published literature22,23 and assumed that approximately 10% of PEs are fatal.

Grading the Evidence and Applicability

We graded the quantity, quality, and consistency of the best available evidence by adapting an evidence-grading scheme recommended by the AHRQ. 24 In assigning evidence grades, we considered the following 4 recommended domains: risk of bias in the included studies, directness of the evidence to the question of interest, consistency across studies, and precision of the pooled estimate or the individual study estimates. We found that few of the studies reported precision, although we were able to calculate confidence intervals for some of the outcomes. We classified results by outcome into the following 4 grades: high (indicating high confidence that the evidence reflects the true effect and that further research is very unlikely to change our confidence in the estimate of the effect), moderate (indicating moderate confidence that the evidence reflects the true effect and that further research may change our confidence in the estimate of the effect and may change the estimate), low (indicating low confidence that the evidence reflects the true effect and that further research is likely to change our confidence in the estimate of the effect and is likely to change the estimate), and insufficient (evidence is unavailable or is so imprecise or of such low quality that the estimate of effect is unreliable).

Study Characteristics

We identified 30 902 unique citations, of which 21 687 were excluded by title screen (Figure 1). Fifty-eight studies addressed IVC filter use in trauma, although most (n = 48) were uncontrolled studies. We included 8 controlled studies that assessed the effectiveness of IVC filter compared with no filter placement on VTE events in trauma patients (Table 1). Of the 8 studies, 1 was a small pilot feasibility RCT25; 2, prospective cohort studies with concurrent comparison groups26,28; 4, prospective cohort studies with historical controls27,2931; and 1, a retrospective cohort study.32 All 8 studies were performed within single institutions in North America, most of which were level I trauma centers.

Place holder to copy figure label and caption
Figure 1.
Flow Diagram of Included and Excluded Studies

We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist13 to refine the search for eligible studies, resulting in 8 controlled studies for analysis. HIT indicates heparin-induced thrombocytopenia; IVC, inferior vena cava; VTE, venous thromboembolism.aTotal exceeds the number excluded because reviewers were allowed to mark more than 1 reason for exclusion.

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Table Graphic Jump LocationTable 1.  Characteristics of Controlled Studies of Prophylactic IVC Filters Among Trauma Patients

All studies analyzed patients in 2 groups. One group received standard therapy alone, and the other group received prophylactic IVC filter placement in addition to standard VTE prevention. The most common standard therapy was a combination of venous compression devices with subcutaneous low-molecular-weight heparin. Most studies used duplex ultrasonography for DVT diagnosis, although some older studies used outdated modalities, such as impedance plethysmography.26,27 For the diagnosis of PE, most studies used computed tomographic angiography, but some used conventional angiography or, infrequently, ventilation/perfusion scans.

We excluded 2 studies26,29 from the pooled analyses because we considered them to have substantial flaws. The first study had severe prognostic imbalance in Injury Severity Scores (ISSs) between study groups (mean ISS, 22.8 vs 9.8, filter vs control).26 The second study was excluded because of concerns about overlapping participants with another study by the same authors from the same institution and the same study period.29

Participant Characteristics

The patients in the controlled observational studies ranged in mean age from 31.4 to 58.4 years. Most of the patients in each study were men (58.0%-96.0%). Seven studies reported mean ISS. Mean ISS for patients receiving IVC filters ranged from 22.8 to 31.5, with 5 of 7 studies reporting a mean ISS greater than 25, a common cutoff for very severe injury. Mean ISS for patients not receiving filters were not uniformly reported, but the scores were lower than those for the patients receiving IVC filters in all 5 studies in which they were reported (Table 1).

Outcomes
Pulmonary Embolism

We included 6 controlled studies for the meta-analysis on PE outcomes.25,27,28,3032 We found fewer PEs with IVC filter use compared with no IVC filter use without evidence of statistical heterogeneity (RR, 0.20 [95% CI, 0.06-0.70]; I2 = 0%) (Figure 2). Our results were robust to alternative approaches for continuity correction and showed largely similar results.

Place holder to copy figure label and caption
Figure 2.
Forest Plot of Relative Risk (RR) of Pulmonary Embolism (PE) With Use of Inferior Vena Cava (IVC) Filters vs No IVC Filters in Trauma Patients

Weights are calculated from random-effects analysis. Dashed line indicates the overall weighted point estimate (0.20); diamond, same overall weighted point estimate (95% CI). Shadow size varies relative to weight assigned to each study. Overall I2 = 0% (P = .48). Test of RR = 1 (z = 2.52; P = .01).

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In the small RCT,25 we found no statistically significant difference in the incidence of PE between the 2 groups, with no PEs in the IVC filter group and 1 PE among patients without filters. Five of the 6 observational studies included in the meta-analysis reported lower PE rates with IVC filter placement2731 (Supplement [eTable 1]). The single study with a higher incidence of PE with IVC filter placement32 included only patients with spinal cord injuries and a single patient who had a PE diagnosed after placement of an IVC filter. Both studies by Rogers et al,26,29 which were excluded from the meta-analysis, reported higher rates of PE. The study that reported ISS26 had dramatically higher ISS in the IVC filter group.

Assuming a baseline risk of PE of 1.15% among trauma patients,22 the NNT to prevent 1 additional PE with IVC filters is estimated to be 109 (95% CI, 93-190). If the lowest reported baseline risk is used (with all National Trauma Data Bank patients in the denominator),23 the NNT is 962 (95% CI, 819-2565) (Supplement [eTable 2]).

Fatal PE

We included 4 studies that reported on fatal PE25,27,30,31; one of these had no events in either arm25 (Figure 3). We found consistent evidence of a reduction in fatal PE with IVC filters compared with no IVC filters, without evidence of statistical heterogeneity (RR, 0.09 [95% CI, 0.01-0.81]; I2 = 0%). Despite the precise and consistent evidence of a reduction in fatal PE with IVC filters, sensitivity analyses with alternative continuity corrections (used if 0 events occurred in 1 treatment arm) were not uniformly robust to the outcome of fatal PE. The Peto odds ratio approach showed a statistically significant reduction in fatal PE (Peto odds ratio, 0.22 [95% CI, 0.08-0.58]), which is consistent with the primary analysis. Alternative continuity corrections, such as the 0.5 correction (RR, 0.22 [95% CI, 0.04-1.16]) or 0.01 correction (0.01 [0-425.5]), were not statistically significant. The NNT to prevent 1 fatal PE with IVC filters is estimated to be 1099 (95% CI, 1011-5264), although this assumption is fragile with multiple assumptions (Supplement [eTable 2]).

Place holder to copy figure label and caption
Figure 3.
Forest Plot of Relative Risk (RR) of Fatal Pulmonary Embolism (PE) With Use of Inferior Vena Cava (IVC) Filters vs No IVC Filters in Trauma Patients

Weights are calculated from random-effects analysis. Dashed line indicates the overall weighted point estimate (0.20); diamond, same overall weighted point estimate (95% CI). Shadow size varies relative to weight assigned to each study. Overall I2 = 0% (P = .94). Test of RR = 1 (z = 2.14; P = .03).

Graphic Jump Location

No fatal PEs occurred in the IVC filter arms of any included study (Supplement [eTable 1]). Twenty fatal PEs occurred in the 407 patients not receiving IVC filters. No VTE-related deaths were recorded in the RCT.25 The prospective cohort study with historical controls identified a statistically significantly higher incidence of fatal PE in patients who did not receive IVC filters (4% vs 0%; P = .03).30

Deep Vein Thrombosis

The RR for the outcome of DVT was 1.76 (95% CI, 0.50-6.19; P = .38).25,31,32 (Supplement [eFigure 1]). Substantial statistical heterogeneity was found among the included studies (I2 = 56.7%). The sensitivity analyses had similar results. In the RCT, only a single DVT was reported (in the IVC filter group), and no significant difference in DVT incidence between groups was found25 (Supplement [eTable 1]).

Mortality

We included 3 studies reporting mortality in the meta-analysis.25,30,31 The pooled RR for the outcome of mortality was 0.70 (95% CI, 0.40-1.23; I2 = 6.7%) (Supplement [eFigure 2]). Our results were robust to alternative approaches for continuity correction and showed largely similar results.

No differences were observed in the RCT with regard to VTE and non-VTE mortality between groups.25 Both non-RCT studies included in the meta-analysis showed nonsignificantly lower all-cause mortality in the IVC filter group compared with the no IVC filter group.

Filter Complications

Filter-related complications were only sparsely reported in the controlled studies. The complete data on complications in these controlled studies and in many uncontrolled studies are contained in the full AHRQ report.15

Risk of Bias

We rated the only small RCT as having a high risk of bias; this was based primarily on issues surrounding blinding of the outcome assessors.25 Among the controlled observational studies, we rated only 1 study as having a moderate risk of bias32 and the remainder as having a high risk of bias.

Strength of Evidence

We rated the strength of evidence as low to support a reduction in PE and fatal PE in trauma patients with the use of IVC filters relative to no use of filters (Table 2). Our estimates for PE were robust to alternative statistical approaches, whereas the estimates for fatal PE were more fragile, and this significant reduction in fatal PE should be viewed with caution. We rated the strength of evidence as insufficient to support a reduction in mortality in trauma with IVC filters. We rated the strength of evidence as insufficient to support any increased or decreased probability of DVT in trauma patients with IVC filters.

Table Graphic Jump LocationTable 2.  Strength of Evidence for Prophylactic IVC Filter vs No IVC Filter in Trauma Patients

Overall, we found low strength of evidence that prophylactic IVC filter placement is associated with a lower incidence of PE and fatal PE in hospitalized trauma patients when compared with no filter use. We found insufficient evidence to comment on mortality or DVT incidence associated with prophylactic IVC filter placement.

We identified only a single RCT, and it had significant methodological limitations. This pilot feasibility trial randomized patients to usual care plus IVC filter or usual care alone and was underpowered for all outcomes. There was significant heterogeneity among the other included controlled studies in design and eligibility and inconsistency in the efficacy outcome assessment methods. Although many of the studies reported on the VTE outcomes, most did not provide details about anatomic locations of the DVTs or the PEs. Some studies did not completely report all outcomes for DVT and PE, which is important because IVC filters may have opposing effects on DVTs and PEs.33 In addition, we found differences in reporting and duration of follow-up. The included studies lacked adequate details about enrolled patient characteristics, such as race and sex and details of the extent and severity of the trauma, limiting our ability to generalize findings from these studies to other ethnic groups or age categories. A wide variation in the use of IVC filters in trauma centers was found that cannot be explained by patient characteristics.12

Our present findings should be interpreted in the context of other systematic reviews. A recent review34 conducted a qualitative synthesis of data from 24 studies and found increasing use of retrievable filters and low rates of filter-related complications. The authors concluded that high-quality data were lacking; therefore, the true efficacy of prophylactic IVC filters for prevention of PE in trauma patients remains unclear. However, they also state that “IVC filters can be used safely and may result in low rates of VTE.”34(p544) A multidisciplinary team35 published a review and guideline for the use of IVC filters in 2006. That report, endorsed by the Society of Interventional Radiology and the American Venous Forum, found that the evidence on optional/removable IVC filters was not sufficient to support evidence-based recommendations. However, the same report lists acceptable indications for a prophylactic IVC filter, including trauma patients with a high risk of VTE in whom primary prophylaxis is not feasible.35 Our review agreed in some regards because we found insufficient evidence that prophylactic IVC filter placement is associated with increased incidence of DVT in trauma patients. However, we found low-strength evidence that IVC filter placement compared with no IVC filter placement is associated with a lower incidence of PE and fatal PE.

Published clinical guidelines on this topic are conflicting. The Eastern Association for the Surgery of Trauma Practice Management Guidelines5 recommends that insertion of prophylactic IVC filters should be considered in very-high-risk trauma patients who cannot receive anticoagulation therapy owing to bleeding risk and who have certain injury patterns rendering them immobilized for a prolonged period (level 3 recommendation). However, this guideline is more than 10 years old and was based primarily on data using permanent IVC filters. The more recent American College of Chest Physicians guideline states that placement of an IVC filter probably reduces the risk of PE during the short term, noting that complications are “frequent” and long-term outcomes are unclear.6 The American College of Chest Physicians document concedes that removable filters may mitigate the long-term complication rate but also noted that they often are not removed. Thus, the American College of Chest Physicians recommends against IVC filters for primary VTE prevention in trauma patients (grade 2C), which is a weak recommendation based on low-quality evidence.6 Perhaps one (or both) of these organizations will use our systematic review and meta-analysis to support an updated guideline.

Our systematic review has several limitations. Our search strategy was comprehensive, and we included study designs other than RCTs; however, we were unable to assess the possibility of publication bias or selective outcomes reporting and its effect on our findings. In addition, the scope of this AHRQ-sponsored project was to “undertake scientific analysis and evidence syntheses” (http://www.ahrq.gov/legacy/clinic/epc/epctopicn.htm), not to produce recommendations or guidelines. This report has performed nearly all of the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) method steps3638 but stops short of making a recommendation. The Eastern Association for the Surgery of Trauma has recently adopted the GRADE method and may perform this additional step in the future.39

Our report highlights the need for additional research on the comparative effectiveness and safety of IVC filters in hospitalized trauma patients. The American Venous Forum and the Society of Interventional Radiology Multidisciplinary Consensus Conference have placed a high priority on studies of IVC filters in trauma.35 The all-too-common answer that RCTs must be performed is at first glance appealing, and Rajasekhar et al25 have shown us that RCTs can be performed on this topic. However, an appropriately powered, multicenter RCT may be prohibitively expensive. We therefore suggest other possible options for well-designed observational research that may be less expensive yet still informative.

Prospective observational studies, such as the National Study on Costs and Outcomes of Trauma, have answered other questions in trauma.40 Perhaps a study such as ours examining VTE prevention in trauma, focused on IVC filters specifically, could be performed. This prospective cohort study could compare an exposed group of trauma patients receiving filters with a carefully matched comparison group of patients with comparable injuries who do not receive IVC filters. A large-scale project like this would likely require a multicenter research collaboration and need national funding and/or sponsorship by a professional trauma organization.

In addition, observational research could be facilitated with use of registry data, such as from the National Trauma Data Bank. Although the National Trauma Data Bank currently contains insufficient detail about IVC filters, this problem could be rectified. Ideally, the registry could include data elements, such as indication, timing of placement, filter type, concomitant pharmacologic prophylaxis, complications, filter removal, and long-term follow-up. A newly published framework regarding ethics of clinical research suggests that not only do clinicians have a moral obligation to perform clinical research but patients are obligated “to contribute to the common purpose of improving the quality and value of clinical care and health care systems.”41(pS19) Retrospective cohort studies are valuable, but they need much better control for confounding by indication (sicker patients received IVC filters more often than less sick patients) than was performed in the included studies. The major flaw of the included retrospective studies was that the authors compared the outcomes for patients receiving filters with those of patients not receiving filters and paid little attention to important underlying clinical differences between these patient groups. Patients receiving IVC filters commonly had more severe injuries and a greater risk for VTE and mortality than did patients not receiving filters. With careful risk adjustment through regression or other methods (eg, propensity score matching, instrumental variable analyses), valid inferences can be drawn from retrospective studies.

The advent of removable IVC filters has been suggested as a major advantage. These removable filters may change the calculation of the benefit to harm ratio for patients by mitigating the long-term complications of having an indwelling IVC filter for life. Filter-related complications may be obviated by filter removal after the high-risk period for PE has passed. These concerns are particularly important considering the relatively young trauma population. However, the premise is based on the assumption that filters are removed in a timely, efficient manner. Some authors note that filters are not removed as frequently as clinicians expect and that many filters are not actually removed from trauma patients.42 Recent efforts to actively and aggressively remove filters through a more disciplined follow-up approach have been shown to be effective in increasing removal rates.43

The baseline risk of all VTE outcomes depends greatly on the use of appropriate, timely VTE prophylaxis in patients at risk. Although once thought to occur late after trauma, PE is frequently found earlier in the hospital course.44,45 However, the use of early pharmacologic thromboprophylaxis in patients considered to be at increased risk of harm from bleeding (eg, traumatic brain injury) remains controversial. The AHRQ report15(pES2) asked the question, “What is the optimal timing of initiation and duration of pharmacologic prophylaxis to prevent VTE in hospitalized patients with traumatic brain injury?” The published data did not allow us to answer this question definitively. However, a retrospective series,46 prospective observational case series,47 and RCT48 appear to show that early pharmacologic thromboprophylaxis is likely safer than originally thought. If pharmacologic prophylaxis is initiated earlier, more patients would receive appropriate VTE prophylaxis, driving down the baseline VTE rate and changing the risk/benefit profile of IVC filters and the NNT to prevent PE and fatal PE.

Clinicians need guidance regarding the use of prophylactic IVC filters in high-risk trauma patients. Overall, we found that prophylactic IVC filter placement is associated with lower incidence of PE and fatal PE in trauma patients. However, risks to patients with IVC filter placement remain, and we were unable to fully examine these risks in this review. In most of the less severely injured trauma patients, particularly those receiving VTE prophylaxis, these risks likely outweigh the benefit of prophylactic IVC filter placement. However, the ratio of benefit to harm likely differs for patients with a higher underlying probability of developing PE, such as those who are more severely injured or who cannot receive pharmacologic prophylaxis. As with many patient care decisions, these difficult clinical judgments must balance the ratio of benefit to harm for individual trauma patients.

Accepted for Publication: May 1, 2013.

Corresponding Author: Elliott R. Haut, MD, Division of Acute Care Surgery, Department of Surgery, The Johns Hopkins Hospital, 1800 Orleans St, Sheikh Zayed 6107C, Baltimore, MD 21287 (ehaut1@jhmi.edu).

Published Online: November 6, 2013. doi:10.1001/jamasurg.2013.3970.

Author Contributions: Drs Haut and Singh had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: Haut, Garcia, Brotman, Sharma, Shermock, Segal, Singh.

Acquisition of data: Haut, Shihab, Brotman, Sharma, Chelladurai, Akande, Shermock, Kebede, Singh.

Analysis and interpretation of data: Haut, Garcia, Shihab, Stevens, Chelladurai, Shermock, Segal.

Drafting of the manuscript: Haut, Garcia, Sharma, Chelladurai, Akande, Shermock, Kebede, Singh.

Critical revision of the manuscript for important intellectual content: Haut, Shihab, Brotman, Stevens, Chelladurai, Shermock, Segal, Singh.

Statistical analysis: Shihab, Chelladurai, Shermock, Singh.

Obtained funding: Segal.

Administrative, technical, or material support: Stevens, Sharma, Chelladurai, Shermock, Kebede.

Study supervision: Haut, Sharma, Chelladurai, Segal.

Conflict of Interest Disclosures: None reported.

Funding/Support: This study was supported by contract HHSA-290-2007-10061 I from the AHRQ.

Role of the Sponsor: The AHRQ participated in formulating the key question and reviewed planned methods and data analyses, as well as interim and final evidence reports. The AHRQ had no role in the preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Additional Contributions: S. Swaroop Vedula, MD, MPH, PhD, helped with the replication of the results in 2 different statistical programs. He did not receive any financial compensation.

US Department of Health and Human Services. Surgeon general’s call to action to prevent deep vein thrombosis and pulmonary embolism 2008. http://www.surgeongeneral.gov/library/calls/deepvein/call-to-action-on-dvt-2008.pdf. Accessed September 25, 2013.
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Carlin  AM, Tyburski  JG, Wilson  RF, Steffes  C.  Prophylactic and therapeutic inferior vena cava filters to prevent pulmonary emboli in trauma patients. Arch Surg. 2002;137(5):521-527.
PubMed   |  Link to Article
McMurtry  AL, Owings  JT, Anderson  JT, Battistella  FD, Gosselin  R.  Increased use of prophylactic vena cava filters in trauma patients failed to decrease overall incidence of pulmonary embolism. J Am Coll Surg. 1999;189(3):314-320.
PubMed   |  Link to Article
Yunus  TE, Tariq  N, Callahan  RE,  et al.  Changes in inferior vena cava filter placement over the past decade at a large community-based academic health center. J Vasc Surg. 2008;47(1):157-165.
PubMed   |  Link to Article
Antevil  JL, Sise  MJ, Sack  DI,  et al.  Retrievable vena cava filters for preventing pulmonary embolism in trauma patients: a cautionary tale. J Trauma. 2006;60(1):35-40.
PubMed   |  Link to Article
Dossett  LA, Adams  RC, Cotton  BA.  Unwarranted national variation in the use of prophylactic inferior vena cava filters after trauma: an analysis of the National Trauma Databank. J Trauma. 2011;70(5):1066-1071.
PubMed   |  Link to Article
Walther  S, Schuetz  GM, Hamm  B, Dewey  M.  Quality of reporting of systematic reviews and meta-analyses: PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) [in German]. Rofo. 2011;183(12):1106-1110.
PubMed   |  Link to Article
Agency for Healthcare Research and Quality. Comparative effectiveness of pharmacologic and mechanical prophylaxis of venous thromboembolism among special populations. http://www.effectivehealthcare.ahrq.gov/ehc/products/341/928/vte-special-populations_protocol_20120112.pdf. Accessed March 21, 2012.
Singh  S, Haut  E, Brotman  D,  et al. Comparative Effectiveness of Pharmacologic and Mechanical Prophylaxis of Venous Thromboembolism Among Special Populations: Evidence Report/Technology Assessment. Rockville, MD: Agency for Healthcare Research & Quality; 2013.
Downs  SH, Black  N.  The feasibility of creating a checklist for the assessment of the methodological quality both of randomised and non-randomised studies of health care interventions. J Epidemiol Community Health. 1998;52(6):377-384.
PubMed   |  Link to Article
DerSimonian  R, Laird  N.  Meta-analysis in clinical trials. Control Clin Trials. 1986;7(3):177-188.
PubMed   |  Link to Article
Sweeting  MJ, Sutton  AJ, Lambert  PC.  What to add to nothing? use and avoidance of continuity corrections in meta-analysis of sparse data. Stat Med. 2004;23(9):1351-1375.
PubMed   |  Link to Article
Bradburn  MJ, Deeks  JJ, Berlin  JA, Russell Localio  A.  Much ado about nothing: a comparison of the performance of meta-analytical methods with rare events. Stat Med. 2007;26(1):53-77.
PubMed   |  Link to Article
StatsDirect [computer program]. Altrincham, England: StatsDirect Ltd; 2008. http://www.statsdirect.com. Accessed March 31, 2012.
Stata Statistical Software [computer program]. Release 11.0. College Station, TX: StataCorp LP; 2009.
Velmahos  GC, Kern  J, Chan  LS, Oder  D, Murray  JA, Shekelle  P.  Prevention of venous thromboembolism after injury: an evidence-based report, I: analysis of risk factors and evaluation of the role of vena caval filters. J Trauma. 2000;49(1):132-139.
PubMed   |  Link to Article
Knudson  MM, Ikossi  DG, Khaw  L, Morabito  D, Speetzen  LS.  Thromboembolism after trauma: an analysis of 1602 episodes from the American College of Surgeons National Trauma Data Bank. Ann Surg. 2004;240(3):490-498.
PubMed   |  Link to Article
Agency for Healthcare Research and Quality. Methods guide for effectiveness and comparative effectiveness reviews. Rockville, MD: Agency for Healthcare Research & Quality; August 2011. AHRQ publication 10(11)-EHC063-EF. http://www.effectivehealthcare.ahrq.gov/. Accessed March 21, 2012.
Rajasekhar  A, Lottenberg  L, Lottenberg  R,  et al.  A pilot study on the randomization of inferior vena cava filter placement for venous thromboembolism prophylaxis in high-risk trauma patients. J Trauma. 2011;71(2):323-329.
PubMed   |  Link to Article
Rogers  FB, Shackford  SR, Ricci  MA, Huber  BM, Atkins  T.  Prophylactic vena cava filter insertion in selected high-risk orthopaedic trauma patients. J Orthop Trauma. 1997;11(4):267-272.
PubMed   |  Link to Article
Wilson  JT, Rogers  FB, Wald  SL, Shackford  SR, Ricci  MA.  Prophylactic vena cava filter insertion in patients with traumatic spinal cord injury: preliminary results. Neurosurgery. 1994;35(2):234-239.
PubMed   |  Link to Article
Gosin  JS, Graham  AM, Ciocca  RG, Hammond  JS.  Efficacy of prophylactic vena cava filters in high-risk trauma patients. Ann Vasc Surg. 1997;11(1):100-105.
PubMed   |  Link to Article
Rogers  FB, Shackford  SR, Ricci  MA, Wilson  JT, Parsons  S.  Routine prophylactic vena cava filter insertion in severely injured trauma patients decreases the incidence of pulmonary embolism. J Am Coll Surg. 1995;180(6):641-647.
PubMed
Khansarinia  S, Dennis  JW, Veldenz  HC, Butcher  JL, Hartland  L.  Prophylactic Greenfield filter placement in selected high-risk trauma patients. J Vasc Surg. 1995;22(3):231-236.
PubMed   |  Link to Article
Rodriguez  JL, Lopez  JM, Proctor  MC,  et al.  Early placement of prophylactic vena caval filters in injured patients at high risk for pulmonary embolism. J Trauma. 1996;40(5):797-804.
PubMed   |  Link to Article
Gorman  PH, Qadri  SF, Rao-Patel  A.  Prophylactic inferior vena cava (IVC) filter placement may increase the relative risk of deep venous thrombosis after acute spinal cord injury. J Trauma. 2009;66(3):707-712.
PubMed   |  Link to Article
Decousus  H, Leizorovicz  A, Parent  F,  et al; Prévention du Risque d’Embolie Pulmonaire par Interruption Cave Study Group.  A clinical trial of vena caval filters in the prevention of pulmonary embolism in patients with proximal deep-vein thrombosis.  N Engl J Med. 1998;338(7):409-415.
PubMed   |  Link to Article
Kidane  B, Madani  AM, Vogt  K, Girotti  M, Malthaner  RA, Parry  NG.  The use of prophylactic inferior vena cava filters in trauma patients: a systematic review. Injury. 2012;43(5):542-547.
PubMed   |  Link to Article
Kaufman  JA, Kinney  TB, Streiff  MB,  et al.  Guidelines for the use of retrievable and convertible vena cava filters: report from the Society of Interventional Radiology Multidisciplinary Consensus Conference. J Vasc Interv Radiol. 2006;17(3):449-459.
PubMed   |  Link to Article
Guyatt  GH, Oxman  AD, Vist  GE,  et al; GRADE Working Group.  GRADE: an emerging consensus on rating quality of evidence and strength of recommendations. BMJ. 2008;336(7650):924-926.
PubMed   |  Link to Article
Guyatt  GH, Oxman  AD, Kunz  R,  et al; GRADE Working Group.  Going from evidence to recommendations. BMJ. 2008;336(7652):1049-1051.
Link to Article
Jaeschke  R, Guyatt  GH, Dellinger  P,  et al; GRADE Working Group.  Use of GRADE grid to reach decisions on clinical practice guidelines when consensus is elusive. BMJ. July 31, 2008;337:a744. doi:10.1136/bmj.a744.
PubMed   |  Link to Article
Kerwin  AJ, Haut  ER, Burns  JB,  et al; Eastern Association for the Surgery of Trauma Practice Management Guidelines Ad Hoc Committee.  The Eastern Association of the Surgery of Trauma approach to practice management guideline development using Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. J Trauma Acute Care Surg. 2012;73(5)(suppl 4):S283-S287.
PubMed   |  Link to Article
MacKenzie  EJ, Rivara  FP, Jurkovich  GJ,  et al.  A national evaluation of the effect of trauma-center care on mortality. N Engl J Med. 2006;354(4):366-378.
PubMed   |  Link to Article
Faden  RR, Kass  NE, Goodman  SN, Pronovost  P, Tunis  S, Beauchamp  TL.  An ethics framework for a learning health care system: a departure from traditional research ethics and clinical ethics. Hastings Cent Rep. 2013;(special issue):S16-S27.
PubMed
Karmy-Jones  R, Jurkovich  GJ, Velmahos  GC,  et al.  Practice patterns and outcomes of retrievable vena cava filters in trauma patients: an AAST multicenter study. J Trauma. 2007;62(1):17-25.
PubMed   |  Link to Article
Rogers  FB, Shackford  SR, Miller  JA, Wu  D, Rogers  A, Gambler  A.  Improved recovery of prophylactic inferior vena cava filters in trauma patients: the results of a dedicated filter registry and critical pathway for filter removal. J Trauma Acute Care Surg. 2012;72(2):381-384.
PubMed
Sing  RF, Camp  SM, Heniford  BT,  et al.  Timing of pulmonary emboli after trauma: implications for retrievable vena cava filters. J Trauma. 2006;60(4):732-735.
PubMed   |  Link to Article
Velmahos  GC, Spaniolas  K, Tabbara  M,  et al.  Pulmonary embolism and deep venous thrombosis in trauma: are they related? Arch Surg. 2009;144(10):928-932.
PubMed   |  Link to Article
Kim  J, Gearhart  MM, Zurick  A, Zuccarello  M, James  L, Luchette  FA.  Preliminary report on the safety of heparin for deep venous thrombosis prophylaxis after severe head injury. J Trauma. 2002;53(1):38-43.
PubMed   |  Link to Article
Norwood  SH, Berne  JD, Rowe  SA, Villarreal  DH, Ledlie  JT.  Early venous thromboembolism prophylaxis with enoxaparin in patients with blunt traumatic brain injury. J Trauma. 2008;65(5):1021-1027.
PubMed   |  Link to Article
Phelan  HA, Wolf  SE, Norwood  SH,  et al.  A randomized, double-blinded, placebo-controlled pilot trial of anticoagulation in low-risk traumatic brain injury: the Delayed Versus Early Enoxaparin Prophylaxis I (DEEP I) study. J Trauma Acute Care Surg. 2012;73(6):1434-1441.
PubMed   |  Link to Article

Figures

Place holder to copy figure label and caption
Figure 1.
Flow Diagram of Included and Excluded Studies

We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist13 to refine the search for eligible studies, resulting in 8 controlled studies for analysis. HIT indicates heparin-induced thrombocytopenia; IVC, inferior vena cava; VTE, venous thromboembolism.aTotal exceeds the number excluded because reviewers were allowed to mark more than 1 reason for exclusion.

Graphic Jump Location
Place holder to copy figure label and caption
Figure 2.
Forest Plot of Relative Risk (RR) of Pulmonary Embolism (PE) With Use of Inferior Vena Cava (IVC) Filters vs No IVC Filters in Trauma Patients

Weights are calculated from random-effects analysis. Dashed line indicates the overall weighted point estimate (0.20); diamond, same overall weighted point estimate (95% CI). Shadow size varies relative to weight assigned to each study. Overall I2 = 0% (P = .48). Test of RR = 1 (z = 2.52; P = .01).

Graphic Jump Location
Place holder to copy figure label and caption
Figure 3.
Forest Plot of Relative Risk (RR) of Fatal Pulmonary Embolism (PE) With Use of Inferior Vena Cava (IVC) Filters vs No IVC Filters in Trauma Patients

Weights are calculated from random-effects analysis. Dashed line indicates the overall weighted point estimate (0.20); diamond, same overall weighted point estimate (95% CI). Shadow size varies relative to weight assigned to each study. Overall I2 = 0% (P = .94). Test of RR = 1 (z = 2.14; P = .03).

Graphic Jump Location

Tables

Table Graphic Jump LocationTable 1.  Characteristics of Controlled Studies of Prophylactic IVC Filters Among Trauma Patients
Table Graphic Jump LocationTable 2.  Strength of Evidence for Prophylactic IVC Filter vs No IVC Filter in Trauma Patients

References

US Department of Health and Human Services. Surgeon general’s call to action to prevent deep vein thrombosis and pulmonary embolism 2008. http://www.surgeongeneral.gov/library/calls/deepvein/call-to-action-on-dvt-2008.pdf. Accessed September 25, 2013.
Geerts  WH, Code  KI, Jay  RM, Chen  E, Szalai  JP.  A prospective study of venous thromboembolism after major trauma. N Engl J Med. 1994;331(24):1601-1606.
PubMed   |  Link to Article
Haut  ER, Chang  DC, Pierce  CA,  et al.  Predictors of posttraumatic deep vein thrombosis (DVT): hospital practice versus patient factors: an analysis of the National Trauma Data Bank (NTDB). J Trauma. 2009;66(4):994-1001.
PubMed   |  Link to Article
Knudson  MM, Gomez  D, Haas  B, Cohen  MJ, Nathens  AB.  Three thousand seven hundred thirty-eight posttraumatic pulmonary emboli: a new look at an old disease. Ann Surg. 2011;254(4):625-632.
PubMed   |  Link to Article
Rogers  FB, Cipolle  MD, Velmahos  G, Rozycki  G, Luchette  FA.  Practice management guidelines for the prevention of venous thromboembolism in trauma patients: the EAST Practice Management Guidelines Work Group. J Trauma. 2002;53(1):142-164.
PubMed   |  Link to Article
Gould  MK, Garcia  DA, Wren  SM,  et al.  Prevention of VTE in nonorthopedic surgical patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines [published correction appears in Chest. 2012;141(5):1369]. Chest. 2012;141(2 suppl):e227S-e2277S. doi:10.1378/chest.11-2297.
PubMed   |  Link to Article
Malinoski  D, Ewing  T, Patel  MS,  et al.  Risk factors for venous thromboembolism in critically ill trauma patients who cannot receive chemical prophylaxis. Injury. 2013;44(1):80-85.
PubMed   |  Link to Article
Carlin  AM, Tyburski  JG, Wilson  RF, Steffes  C.  Prophylactic and therapeutic inferior vena cava filters to prevent pulmonary emboli in trauma patients. Arch Surg. 2002;137(5):521-527.
PubMed   |  Link to Article
McMurtry  AL, Owings  JT, Anderson  JT, Battistella  FD, Gosselin  R.  Increased use of prophylactic vena cava filters in trauma patients failed to decrease overall incidence of pulmonary embolism. J Am Coll Surg. 1999;189(3):314-320.
PubMed   |  Link to Article
Yunus  TE, Tariq  N, Callahan  RE,  et al.  Changes in inferior vena cava filter placement over the past decade at a large community-based academic health center. J Vasc Surg. 2008;47(1):157-165.
PubMed   |  Link to Article
Antevil  JL, Sise  MJ, Sack  DI,  et al.  Retrievable vena cava filters for preventing pulmonary embolism in trauma patients: a cautionary tale. J Trauma. 2006;60(1):35-40.
PubMed   |  Link to Article
Dossett  LA, Adams  RC, Cotton  BA.  Unwarranted national variation in the use of prophylactic inferior vena cava filters after trauma: an analysis of the National Trauma Databank. J Trauma. 2011;70(5):1066-1071.
PubMed   |  Link to Article
Walther  S, Schuetz  GM, Hamm  B, Dewey  M.  Quality of reporting of systematic reviews and meta-analyses: PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) [in German]. Rofo. 2011;183(12):1106-1110.
PubMed   |  Link to Article
Agency for Healthcare Research and Quality. Comparative effectiveness of pharmacologic and mechanical prophylaxis of venous thromboembolism among special populations. http://www.effectivehealthcare.ahrq.gov/ehc/products/341/928/vte-special-populations_protocol_20120112.pdf. Accessed March 21, 2012.
Singh  S, Haut  E, Brotman  D,  et al. Comparative Effectiveness of Pharmacologic and Mechanical Prophylaxis of Venous Thromboembolism Among Special Populations: Evidence Report/Technology Assessment. Rockville, MD: Agency for Healthcare Research & Quality; 2013.
Downs  SH, Black  N.  The feasibility of creating a checklist for the assessment of the methodological quality both of randomised and non-randomised studies of health care interventions. J Epidemiol Community Health. 1998;52(6):377-384.
PubMed   |  Link to Article
DerSimonian  R, Laird  N.  Meta-analysis in clinical trials. Control Clin Trials. 1986;7(3):177-188.
PubMed   |  Link to Article
Sweeting  MJ, Sutton  AJ, Lambert  PC.  What to add to nothing? use and avoidance of continuity corrections in meta-analysis of sparse data. Stat Med. 2004;23(9):1351-1375.
PubMed   |  Link to Article
Bradburn  MJ, Deeks  JJ, Berlin  JA, Russell Localio  A.  Much ado about nothing: a comparison of the performance of meta-analytical methods with rare events. Stat Med. 2007;26(1):53-77.
PubMed   |  Link to Article
StatsDirect [computer program]. Altrincham, England: StatsDirect Ltd; 2008. http://www.statsdirect.com. Accessed March 31, 2012.
Stata Statistical Software [computer program]. Release 11.0. College Station, TX: StataCorp LP; 2009.
Velmahos  GC, Kern  J, Chan  LS, Oder  D, Murray  JA, Shekelle  P.  Prevention of venous thromboembolism after injury: an evidence-based report, I: analysis of risk factors and evaluation of the role of vena caval filters. J Trauma. 2000;49(1):132-139.
PubMed   |  Link to Article
Knudson  MM, Ikossi  DG, Khaw  L, Morabito  D, Speetzen  LS.  Thromboembolism after trauma: an analysis of 1602 episodes from the American College of Surgeons National Trauma Data Bank. Ann Surg. 2004;240(3):490-498.
PubMed   |  Link to Article
Agency for Healthcare Research and Quality. Methods guide for effectiveness and comparative effectiveness reviews. Rockville, MD: Agency for Healthcare Research & Quality; August 2011. AHRQ publication 10(11)-EHC063-EF. http://www.effectivehealthcare.ahrq.gov/. Accessed March 21, 2012.
Rajasekhar  A, Lottenberg  L, Lottenberg  R,  et al.  A pilot study on the randomization of inferior vena cava filter placement for venous thromboembolism prophylaxis in high-risk trauma patients. J Trauma. 2011;71(2):323-329.
PubMed   |  Link to Article
Rogers  FB, Shackford  SR, Ricci  MA, Huber  BM, Atkins  T.  Prophylactic vena cava filter insertion in selected high-risk orthopaedic trauma patients. J Orthop Trauma. 1997;11(4):267-272.
PubMed   |  Link to Article
Wilson  JT, Rogers  FB, Wald  SL, Shackford  SR, Ricci  MA.  Prophylactic vena cava filter insertion in patients with traumatic spinal cord injury: preliminary results. Neurosurgery. 1994;35(2):234-239.
PubMed   |  Link to Article
Gosin  JS, Graham  AM, Ciocca  RG, Hammond  JS.  Efficacy of prophylactic vena cava filters in high-risk trauma patients. Ann Vasc Surg. 1997;11(1):100-105.
PubMed   |  Link to Article
Rogers  FB, Shackford  SR, Ricci  MA, Wilson  JT, Parsons  S.  Routine prophylactic vena cava filter insertion in severely injured trauma patients decreases the incidence of pulmonary embolism. J Am Coll Surg. 1995;180(6):641-647.
PubMed
Khansarinia  S, Dennis  JW, Veldenz  HC, Butcher  JL, Hartland  L.  Prophylactic Greenfield filter placement in selected high-risk trauma patients. J Vasc Surg. 1995;22(3):231-236.
PubMed   |  Link to Article
Rodriguez  JL, Lopez  JM, Proctor  MC,  et al.  Early placement of prophylactic vena caval filters in injured patients at high risk for pulmonary embolism. J Trauma. 1996;40(5):797-804.
PubMed   |  Link to Article
Gorman  PH, Qadri  SF, Rao-Patel  A.  Prophylactic inferior vena cava (IVC) filter placement may increase the relative risk of deep venous thrombosis after acute spinal cord injury. J Trauma. 2009;66(3):707-712.
PubMed   |  Link to Article
Decousus  H, Leizorovicz  A, Parent  F,  et al; Prévention du Risque d’Embolie Pulmonaire par Interruption Cave Study Group.  A clinical trial of vena caval filters in the prevention of pulmonary embolism in patients with proximal deep-vein thrombosis.  N Engl J Med. 1998;338(7):409-415.
PubMed   |  Link to Article
Kidane  B, Madani  AM, Vogt  K, Girotti  M, Malthaner  RA, Parry  NG.  The use of prophylactic inferior vena cava filters in trauma patients: a systematic review. Injury. 2012;43(5):542-547.
PubMed   |  Link to Article
Kaufman  JA, Kinney  TB, Streiff  MB,  et al.  Guidelines for the use of retrievable and convertible vena cava filters: report from the Society of Interventional Radiology Multidisciplinary Consensus Conference. J Vasc Interv Radiol. 2006;17(3):449-459.
PubMed   |  Link to Article
Guyatt  GH, Oxman  AD, Vist  GE,  et al; GRADE Working Group.  GRADE: an emerging consensus on rating quality of evidence and strength of recommendations. BMJ. 2008;336(7650):924-926.
PubMed   |  Link to Article
Guyatt  GH, Oxman  AD, Kunz  R,  et al; GRADE Working Group.  Going from evidence to recommendations. BMJ. 2008;336(7652):1049-1051.
Link to Article
Jaeschke  R, Guyatt  GH, Dellinger  P,  et al; GRADE Working Group.  Use of GRADE grid to reach decisions on clinical practice guidelines when consensus is elusive. BMJ. July 31, 2008;337:a744. doi:10.1136/bmj.a744.
PubMed   |  Link to Article
Kerwin  AJ, Haut  ER, Burns  JB,  et al; Eastern Association for the Surgery of Trauma Practice Management Guidelines Ad Hoc Committee.  The Eastern Association of the Surgery of Trauma approach to practice management guideline development using Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. J Trauma Acute Care Surg. 2012;73(5)(suppl 4):S283-S287.
PubMed   |  Link to Article
MacKenzie  EJ, Rivara  FP, Jurkovich  GJ,  et al.  A national evaluation of the effect of trauma-center care on mortality. N Engl J Med. 2006;354(4):366-378.
PubMed   |  Link to Article
Faden  RR, Kass  NE, Goodman  SN, Pronovost  P, Tunis  S, Beauchamp  TL.  An ethics framework for a learning health care system: a departure from traditional research ethics and clinical ethics. Hastings Cent Rep. 2013;(special issue):S16-S27.
PubMed
Karmy-Jones  R, Jurkovich  GJ, Velmahos  GC,  et al.  Practice patterns and outcomes of retrievable vena cava filters in trauma patients: an AAST multicenter study. J Trauma. 2007;62(1):17-25.
PubMed   |  Link to Article
Rogers  FB, Shackford  SR, Miller  JA, Wu  D, Rogers  A, Gambler  A.  Improved recovery of prophylactic inferior vena cava filters in trauma patients: the results of a dedicated filter registry and critical pathway for filter removal. J Trauma Acute Care Surg. 2012;72(2):381-384.
PubMed
Sing  RF, Camp  SM, Heniford  BT,  et al.  Timing of pulmonary emboli after trauma: implications for retrievable vena cava filters. J Trauma. 2006;60(4):732-735.
PubMed   |  Link to Article
Velmahos  GC, Spaniolas  K, Tabbara  M,  et al.  Pulmonary embolism and deep venous thrombosis in trauma: are they related? Arch Surg. 2009;144(10):928-932.
PubMed   |  Link to Article
Kim  J, Gearhart  MM, Zurick  A, Zuccarello  M, James  L, Luchette  FA.  Preliminary report on the safety of heparin for deep venous thrombosis prophylaxis after severe head injury. J Trauma. 2002;53(1):38-43.
PubMed   |  Link to Article
Norwood  SH, Berne  JD, Rowe  SA, Villarreal  DH, Ledlie  JT.  Early venous thromboembolism prophylaxis with enoxaparin in patients with blunt traumatic brain injury. J Trauma. 2008;65(5):1021-1027.
PubMed   |  Link to Article
Phelan  HA, Wolf  SE, Norwood  SH,  et al.  A randomized, double-blinded, placebo-controlled pilot trial of anticoagulation in low-risk traumatic brain injury: the Delayed Versus Early Enoxaparin Prophylaxis I (DEEP I) study. J Trauma Acute Care Surg. 2012;73(6):1434-1441.
PubMed   |  Link to Article

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