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Review |

Pharmacologic and Mechanical Strategies for Preventing Venous Thromboembolism After Bariatric Surgery:  A Systematic Review and Meta-analysis FREE

Daniel J. Brotman, MD1; Hasan M. Shihab, MBChB, MPH2; Kalpana R. Prakasa, MBBS, MS1; Sosena Kebede, MD, MPH1; Elliott R. Haut, MD3; Ritu Sharma, BSc2; Kenneth Shermock, PharmD, PhD1,2; Yohalakshmi Chelladurai, MBBS, MPH2; Sonal Singh, MD, MPH1,2; Jodi B. Segal, MD, MPH1,2
[+] Author Affiliations
1Department of Medicine, The Johns Hopkins School of Medicine, The Johns Hopkins University, Baltimore, Maryland
2Health Policy and Management, The Johns Hopkins Bloomberg University School of Public Health, The Johns Hopkins University, Baltimore, Maryland
3Department of Surgery, The Johns Hopkins School of Medicine, The Johns Hopkins University, Baltimore, Maryland
JAMA Surg. 2013;148(7):675-686. doi:10.1001/jamasurg.2013.72.
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Published online

We sought to assess the comparative effectiveness and safety of pharmacologic and mechanical strategies to prevent venous thromboembolism (VTE) in patients undergoing bariatric surgery. We searched (through August 2012) for primary studies that had at least 2 different interventions. Of 30 902 citations, we identified 8 studies of pharmacologic strategies and 5 studies of filter placement. No studies randomized patients to receive different interventions. One study suggested that low-molecular-weight heparin is more efficacious than unfractionated heparin in preventing VTE (0.25% vs 0.68%, P < .001), with no significant difference in bleeding. One study suggested that prolonged therapy (after discharge) with enoxaparin sodium may prevent VTE better than inpatient treatment only. There was insufficient evidence supporting the hypothesis that filters reduce the risk of pulmonary embolism, with a point estimate suggesting increased rates with filters (pooled relative risk [RR], 1.21 95% CI, 0.57-2.56). There was low-grade evidence that filters are associated with higher mortality (pooled RR, 4.30 95% CI, 1.60-11.54) and higher deep vein thrombosis rates (2.94 1.35-6.38). There was insufficient evidence to support that augmented subcutaneous enoxaparin doses (>40 mg daily or 30 mg twice daily) are more efficacious than standard dosing, with a trend toward increased bleeding. Of note, for both filters and augmented pharmacologic dosing strategies, patients at highest risk for VTE were more likely to receive more intensive interventions, limiting our ability to attribute outcomes to prophylactic strategies used.

Figures in this Article

Prophylaxis to prevent venous thromboembolism (VTE) is recommended for patients undergoing abdominal surgery and may include pharmacologic prophylaxis or mechanical measures, sometimes in combination.1 Because patients undergoing bariatric surgery are often morbidly obese, it has been suggested that they may require more aggressive VTE prophylaxis than other surgical patients.2 Obesity itself is a risk factor for VTE3 and may lead to restricted mobility and conditions associated with VTE, such as hypertension, diabetes mellitus, and venous stasis.4 Also, drug regimens used to prevent thrombosis in surgical patients generally are given in fixed doses that do not account for body weight.5

Strategies to augment VTE protection in patients undergoing bariatric surgery may include higher-than-standard (ie, augmented) dosing of usual pharmacotherapy (eg, >40 mg daily or 30 mg twice daily of enoxaparin sodium) and placement of inferior vena cava filters before surgery. The optimal approach to prophylaxis, however, remains unclear.6 Based on the varying practice patterns among surgeons and limited guideline recommendations addressing this population specifically, we performed a systematic review to address the comparative effectiveness of pharmacologic and mechanical VTE prevention strategies in patients undergoing bariatric surgery.

This report describes strategies for preventing VTE in patients undergoing bariatric surgery. Additional methodologic details are in our evidence report prepared for the Agency for Healthcare Research and Quality7 the full protocol was posted online (http://effectivehealthcare.ahrq.gov/index.cfm/search-for-guides-reviews-and-reports/?pageaction=displayproduct&productid=928#4369).

Data Sources and Search

We searched the following databases for primary studies through August 2012: MEDLINE, EMBASE, Scopus, CINAHL, International Pharmaceutical Abstracts, clinicaltrials.gov, and the Cochrane Library. Our search strategy was defined a priori (eAppendix in Supplement). We reviewed reference lists of all included articles, relevant review articles, and related systematic reviews to identify additional publications. We reviewed Scientific Information Packets from pharmaceutical manufacturers and requested that the Agency for Healthcare Research and Quality peer reviewers alert us to any published or unpublished data that we may have missed.

Study Selection

Two investigators independently reviewed titles and then abstracts abstracts were excluded if both investigators agreed that the article met 1 or more of the exclusion criteria. All investigators participated in this process. We included only studies that described 2 or more interventions, including devices, drugs, varying doses, or varying durations of therapy. We studied only drugs available in the United States in 2011. We included only studies that focused on clinical end points (rather than pharmacokinetic end points or subjective end points such as satisfaction).

Outcomes

Prospectively identified outcomes included (1) pulmonary embolism (PE), fatal and nonfatal (2) deep vein thrombosis (DVT), including vena cava thrombosis (3) bleeding as defined by the investigators of each study (4) all-cause mortality (5) filter complications and (6) adverse drug reactions.

Data Abstraction and Quality Assessment

We used a data extraction tool (DistillerSR, 2010 version Evidence Partners) to manage the screening and review process. Paired investigators reviewed all extracted data, with disagreements resolved by consensus. We assessed the risk of bias for each study independently and in duplicate, using 10 items from the Downs and Black8 instrument that we found most relevant to this review. Studies could be considered to have low risk of bias only if allocation to interventions was randomized and blinded.

Data Synthesis and Analysis

For outcomes reported in 3 or more studies, we used I2 values to assess heterogeneity (with >50% defined as high heterogeneity). We used random-effects models to estimate pooled effect sizes, with 95% CIs for individual studies.

Grading the Evidence and Applicability

We graded the quantity, quality, and consistency of evidence by adapting a grading scheme recommended in the Methods Guide for Effectiveness and Comparative Effectiveness Reviews.9 We placed evidence into 4 categories: high, moderate, and low (reflecting the degree of confidence that the evidence reflects a true effect) and insufficient.

Study Characteristics

There were 30 902 unique citations identified by the electronic search (Figure 1). Two additional articles were identified by an Agency for Healthcare Research and Quality peer reviewer that were not yet published but provided updated analyses from a large multicenter registry.10,11 To avoid double-counting patients, we eliminated an earlier report from the same registry.12 We ultimately included 13 articles,11,1324 including 5 that included patients with and without filters (Table 1)11,15,17,19,24 and 8 that included patients receiving different pharmacologic regimens (Table 2).10,13,14,16,18,22,23,25 All included studies used an observational cohort design.

Place holder to copy figure label and caption
Figure 1.
Flow Diagram of Studies Included in the Systematic Review

HIT indicates heparin-induced thrombocytopenia and VTE, venous thromboembolism. *Total exceeds the number in the exclusion box because reviewers were allowed to mark more than 1 reason for exclusion.

Graphic Jump Location
Table Graphic Jump LocationTable 1.  Characteristics of Studies of Inferior Vena Cava Filters Among Patients Undergoing Bariatric Surgery
Table Graphic Jump LocationTable 2.  Characteristics of Studies of Pharmacologic Comparisons Among Patients Undergoing Bariatric Surgery
Participant Characteristics

Patients underwent bariatric procedures, including Roux-en-Y gastric bypass (predominantly laparoscopic), sleeve gastrectomy, adjustable laparoscopic gastric banding, and biliary-pancreatic diversion. Patient characteristics were generally consistent across studies. Most reports did not describe the prevalence of prior VTE. Duration of follow-up was generally 2 to 6 weeks however, one study reported follow-up of more than 2 years.23

Patient and hospitalization characteristics varied by treatment allocation. More intensive prophylaxis often was targeted toward patients at higher thrombosis risks. In the registry studies by Birkmeyer et al10,11 and Li et al,24 patients receiving filters tended to have lower baseline mobility, be men, and have a prior history of VTE. Overby et al15 offered filters to patients with elevated levels of coagulation markers, impaired mobility, severe sleep apnea or hypoventilation, prior VTE, and more severe obesity. Obeid et al17 preferentially placed filters in the most obese patients and in those with prior VTE.

Higher-intensity pharmacologic regimens were prescribed preferentially for higher-risk surgical patients depending on type of surgery (laparoscopic vs open), duration of surgery, or length of hospital stay. Of the 3 studies16,22,23 of pharmacologic prophylaxis that used enoxaparin doses of 60 mg twice daily, 2 studies22,23 did so only in the most obese patients. In the single study14 of prolonged pharmacologic prophylaxis vs inpatient prophylaxis alone, 132 patients who underwent surgery between 2003 and 2005 received 30 mg twice daily of enoxaparin subcutaneously starting 1 hour preoperatively and continuing through hospitalization, which averaged 3.0 days. A second group of 176 patients who underwent surgery in 2006 and 2007 received enoxaparin starting 12 hours postoperatively, continuing throughout hospitalization (averaging 2.2 days) and for 10 days after discharge. In addition to the significantly shorter length of stay in the second group, patients in this group had fewer open procedures (0 vs 4 patients) and fewer conversions to open procedures after failed laparoscopic interventions (0 vs 5 patients).

Interventions

Filter types varied according to physician practice and preference and included the retrievable Gunther Tulip (Cook Medical), Bard Recovery (Bard), OptEase (Cordis Corporation), Cook Celect (Cook Medical), and Bard G2 (Bard), as well as filters that generally are not intended for retrieval, including the Greenfield stainless steel (Boston Scientific), Simon Nitinol (Bard), and Cordis TRAPEASE (Cordis) filters. The registry studies by Birkmeyer et al11 and Li et al24 did not report specific filter types. Concurrent use of sequential compression devices and pharmacotherapy (enoxaparin, heparin sodium, or warfarin sodium) was described by some authors.15,17 Only one study15 reported filter retrieval rates, at 92%.

Enoxaparin and unfractionated heparin were the only drugs evaluated specifically however, one registry study10 combined patients taking any low-molecular-weight heparin (LMWH) into a single group. Five studies13,16,18,22,23 featured varying doses of enoxaparin, 2 studies22,23 of which used weight-based dosing. In the study25 that included patients receiving either enoxaparin or unfractionated heparin, one group of patients received 40 mg of enoxaparin subcutaneously twice daily and another group received 5000 U of unfractionated heparin subcutaneously every 8 hours. In one study,14 all patients received 30 mg of enoxaparin subcutaneously twice daily, but the timing and duration of prophylaxis differed between the 2 comparison groups. Dosing regimens of enoxaparin ranged from 30 mg once daily to 60 mg twice daily (Table 2). We categorized doses as standard prophylactic dosing (enoxaparin, 30 mg twice daily or 40 mg once daily, and heparin, 5000 U every 8 hours) or augmented dosing, including enoxaparin, 40 mg, 50 mg, and 60 mg twice daily. According to this classification, 3 studies13,18,23 included groups of patients receiving standard vs augmented dosing, and 3 studies16,22,23 compared 2 or more augmented dosing regimens. One of these studies18 also included patients receiving reduced enoxaparin dosing (30 mg once daily). One registry study10 compared unfractionated heparin with LMWH but did not account for different dosing strategies. Four studies13,14,23,25 initiated pharmacotherapy prior to surgery, and 2 studies16,22 initiated pharmacotherapy after surgery the timing was variable in the 5-center study by Hamad and Choban.18 The planned duration of pharmacotherapy was for the entire hospital stay in 2 studies,14,25 until “fully ambulatory” or hospital discharge in 1 study,13 for 2 weeks postoperatively in 1 study,16 for 10 days following discharge in 1 study,22 was not clearly specified in 2 publications,11,23 and varied by center in another investigation.18 Some studies described concurrent mechanical prophylaxis, including pneumatic compression13,14,22,23,25 and early ambulation.13,22,23 None of the reports indicated that these nonpharmacologic prophylactic measures were delivered to only 1 treatment arm.

Outcomes

Most studies relied on clinically diagnosed (symptomatic) thrombosis and did not use routine surveillance for VTE prior to hospital discharge. However, one study15 reported using ultrasonography and/or computed tomographic venography prior to filter removal, and another14 reported performing bilateral lower extremity ultrasonography before discharge.

Inferior Vena Cava Filter vs No Inferior Vena Cava Filter

In studies of filter use, there was substantial variability with regard to PE and mortality (Table 3 and Figures 2, 3, and 4). Gargiulo et al19 reported no PEs among 58 patients receiving filters and 9 PEs among 351 patients who did not receive filters, of which 5 PEs were fatal. However, the large registry studies by Li et al24 and Birkmeyer et al11,12 found higher PE rates among patients with filters. There also was consistency in that filters were associated with higher rates of DVT (Table 3 and Figure 3).

Table Graphic Jump LocationTable 3.  Venous Thromboembolism Outcomes Among Patients Undergoing Bariatric Surgery Who Received Inferior Vena Cava Filters vs Control
Place holder to copy figure label and caption
Figure 2.
Relative Risk (RR) Meta-analysis of inferior Vena Cava Filters (IVCFs) in Preventing Pulmonary Embolism in Patients Undergoing Bariatric Surgery

The shaded box sizes are proportional to the weight of each study blue diamond shows the CI of the pooled effect size. Black bars denote CIs for individual studies, and dotted line indicates the pooled effect estimate.

Graphic Jump Location
Place holder to copy figure label and caption
Figure 3.
Relative Risk (RR) Meta-analysis of Inferior Vena Cava Filters (IVCFs) and Deep Vein Thrombosis in Patients Undergoing Bariatric Surgery
Graphic Jump Location
Place holder to copy figure label and caption
Figure 4.
Relative Risk (RR) Meta-analysis of Inferior Vena Cava Filters (IVCFs) and Mortality in Patients Undergoing Bariatric Surgery
Graphic Jump Location

Reported filter complications included filter migration to the heart requiring heart valve replacement (1 patient),11 fatal inferior vena cava thrombosis (2 patients),11 pneumothorax (1 patient),15 hemopericardium (1 patient),15 contrast nephropathy (1 patient),11 incision site infection (1 patient),11 and the inability to perform transvenous ablation of a cardiac accessory pathway because of the filter (1 patient).15

LMWH vs Unfractionated Heparin

Two studies compared unfractionated heparin with LMWH11,25 (Table 4 and Table 5). In the study by Kothari et al25 comparing enoxaparin, 40 mg administered subcutaneously twice daily, with unfractionated heparin, 5000 U administered every 8 hours, a single PE occurred in the heparin-treated patients (0.42%), with no thrombotic events in the enoxaparin-treated patients. Bleeding events requiring transfusion and reoperation were higher among enoxaparin-treated patients. The registry study by Birkmeyer et al10 compared patients receiving LMWH regimens with those receiving unfractionated heparin regimens (doses not specified) and found that patients who received prophylaxis with LMWH preoperatively and postoperatively had a lower adjusted rate of VTE (0.25%) than did those receiving unfractionated heparin preoperatively and postoperatively (0.68%) (P < .001). Bleeding occurred in a similar percentage of patients receiving unfractionated heparin and LMWH (adjusted rates, 1.69% and 1.65%, respectively adjusted odds ratio, 0.94 95% CI, 0.63-1.41 P = .78), with major bleeding (>4 U of blood transfused or reoperation) in 0.46% and 0.38%, respectively (adjusted OR, 0.75 95% CI, 0.38-1.47 P = .40).

Table Graphic Jump LocationTable 4.  Venous Thromboembolism Outcomes Among Bariatric Surgery Patients Undergoing Pharmacologic Prophylaxis
Table Graphic Jump LocationTable 5.  Safety Profile of Pharmacologic Interventions to Prevent Venous Thromboembolism in Bariatric Surgical Patients
Enoxaparin vs Extended-Duration Enoxaparin

Raftopoulos et al14 reported thrombotic events in 6 of 132 patients (4.5%) receiving short-term enoxaparin prophylaxis and none of 176 patients receiving extended prophylaxis (P = .006) (Tables 4 and 5). This difference remained statistically significant after excluding patients who required conversion to open procedures (P= 0.03). Bleeding requiring reoperation occurred in 1 patient from each group.

Enoxaparin at Standard vs Augmented Dosing

Three studies13,18,23 reported on VTE outcomes in patients receiving standard vs augmented enoxaparin dosing (Tables 4 and 5). In the study by Scholten et al,13 among 92 patients receiving enoxaparin, 30 mg twice daily (standard dosing), there were 5 thrombotic events (5.4%), whereas among 389 patients who received 40 mg twice daily (augmented), there were 2 thrombotic events (0.5%). In the studies by Singh et al23 and Hamad and Choban,18 rates of VTE were comparable for patients receiving different doses of enoxaparin. None of the 3 studies reported any perioperative deaths. Bleeding events were infrequent but slightly more common overall with augmented dosing.

Strength of Evidence

All included studies were rated as having a high risk of bias except 2 of them10,11 that we rated as having a moderate risk of bias (Table 6 and Table 7). The preference of the surgical team or the protocol used at the center during a particular time frame usually defined the prophylactic strategy, and interventions often were allocated on the basis of real or perceived risk factors for postoperative VTE, such as prior VTE, age, degree of immobility, or severity of obesity. This targeted approach would tend to bias toward poorer efficacy with more aggressive prophylactic strategies because these were used in patients at higher risk. None of the studies performed multivariable adjustments to account for patient differences according to intervention allocation except the 2 that we rated as having moderate risk of bias.10,11 None of the studies focusing on differing intensity, timing, or duration of pharmacologic prophylaxis used multivariable adjustment to account for differences between patients receiving different prophylactic strategies.

Table Graphic Jump LocationTable 6.  Body of Evidence for IVCF vs Controls for the Prevention of PE in Patients Undergoing Bariatric Surgery1
Table Graphic Jump LocationTable 7.  Body of Evidence for Pharmacologic Prophylaxis for the Prevention of Venous Thromboembolism in Patients Undergoing Bariatric Surgery

For filters, there was consistency suggesting a higher risk of DVT in patients receiving the intervention however, based on the limitations of the source data, we graded the strength of evidence as low. We also graded the strength of evidence that filters do not prevent PE or total mortality as low. We rated the strength of evidence as insufficient for all outcomes and comparisons in studies that evaluated pharmacologic interventions because of the inconsistencies and imprecision in the body of evidence.

Overall, our findings support the use of “standard” doses of pharmacotherapy as prophylaxis for patients undergoing bariatric surgery, consistent with current American College of Chest Physicians guidelines,1 which do not distinguish between patients undergoing bariatric surgery and those undergoing other types of abdominal surgery. Similarly, a position statement issued by the Clinical Issues Committee of the American Society for Metabolic and Bariatric Surgery26 declined to recommend any specific anticoagulant or filter placement strategy in bariatric surgery patients but did recommend that those without contraindications to anticoagulation prophylaxis should generally receive it. We found no evidence to support filter placement as prophylaxis in patients undergoing bariatric surgery, with a trend toward higher DVT rates and higher mortality in patients receiving filters. Based on one study that evaluated LMWH vs unfractionated heparin and found that the rate of thrombosis was significantly lower with LMWH10 and another study that evaluated prolonged prophylaxis for 10 days after hospital discharge and found that thrombosis rates were significantly lower with prolonged prophylaxis,14 clinicians may consider either or both of these approaches. The rate of fatal PE appears to be low in patients receiving pharmacologic prophylaxis when used in conjunction with compression devices or stockings and early ambulation. In addition, studies that focused on inferior vena cava filters generally included patients receiving concurrent pharmacologic prophylaxis.

Our systematic review identified important weaknesses in the literature. We found no randomized clinical trials addressing the comparative effectiveness of differing interventions to prevent VTE in patients undergoing bariatric surgery, and only 2 studies (one of filters11 and the other of pharmacotherapy10) used multivariable analysis to account for differences between patients allocated to different interventions. As such, all studies were observational and most had a high risk of bias. The greatest risk to their validity was confounding by indication in that sicker patients received more intense prophylaxis, with no or inadequate adjustment for differences between treatment groups. In the absence of randomized trials, we were unable to determine the comparative effectiveness and safety or the optimal timing and duration of prophylactic pharmacotherapy. The observational studies did not provide a clear association between the use of preoperative initiation of pharmacologic prophylaxis and perioperative bleeding or between postoperative initiation of pharmacologic prophylaxis and thrombosis.

Our findings are likely to be generalizable. Patient characteristics were consistent with those expected in the bariatric surgery population, including obese middle-aged individuals of both sexes. Types of surgeries included the types of bariatric procedures frequently performed in the United States most were laparoscopic. Most studies did not report race, so we cannot make conclusions related to potential interactions between race and prophylactic strategy. Although many studies reported single-center experiences, patient characteristics and surgery types appeared to be relatively consistent across study centers. The single-center design of these studies, by itself, is not a major factor limiting generalizability, since the characteristics of patients were similar to those in other centers.

In contrast to this comparative effectiveness review, which evaluated only comparative studies, Becattini et al27 conducted a systematic review of pharmacologic strategies for VTE prevention in bariatric surgery that included uncontrolled single-arm studies of pharmacologic prophylaxis in an effort to define VTE incidence rates with varying pharmacotherapy regimens. They concluded that the incidence of symptomatic postoperative VTE appeared to be less than 1% with both prophylactic strategies, but that with active VTE surveillance, the rate was approximately 2%. Bleeding rates were approximately 1% for standard-dose regimens, and 1.6% for weight-adjusted (augmented) pharmacologic prophylaxis. The authors concluded that there might be a higher rate of bleeding with augmented dosing with no evidence of increased efficacy, similar to our findings.

Our systematic review has several limitations. Although our search strategy was comprehensive, we may have missed a few studies. We were unable to assess the possibility of publication bias or selective outcomes reporting and its effect on our findings. In addition, as noted above, our findings are limited because of the high overall risk of bias of the included studies.

In summary, despite the limitations of the existing literature, we did not find evidence to support the use of filters or augmented dosing of pharmacotherapy in patients undergoing bariatric surgery. We note that, despite the patient population, which might be assumed to be at particularly high risk of postoperative VTE because of their body habitus, rates of thrombosis and mortality were reassuringly low. Although we did not specifically evaluate the impact of minimally invasive operative techniques, early ambulation, and noninvasive mechanical measures to prevent thrombosis in these patients, most authors emphasized using these approaches. We suspect that these supplemental strategies may be one reason that overall VTE rates and associated mortality are acceptably low in the bariatric surgical population even when using the standard pharmacologic prophylactic approaches that are used in nonobese perioperative patients.

Accepted for Publication: December 26, 2012.

Corresponding Author: Daniel J. Brotman, MD, The Johns Hopkins Hospital, 1830 E Monument St, Room 8038, Baltimore, MD 21287 (brotman@jhmi.edu).

Published Online: May 29, 2013. doi:10.1001/jamasurg.2013.72

Author Contributions: The authors of this article are responsible for its contents, including any clinical or treatment recommendations.

Study concept and design: Brotman, Kebede, Haut, Sharma, Shermock, Chelladurai, Singh.

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

Analysis and interpretation of data: Brotman, Shihab, Prakasa, Haut, Shermock, Chelladurai, Singh, Segal.

Drafting of the manuscript: Brotman, Kebede, Sharma, Shermock, Segal.

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

Statistical analysis: Shihab, Prakasa, Shermock, Chelladurai, Singh.

Obtained funding: Segal. Administrative, technical, and material support: Kebede, Sharma, Shermock, Chelladurai.

Study supervision: Brotman, Sharma, and Segal.

Conflict of Interest Disclosures: None reported.

Funding/Support: This study was funded by the Agency for Healthcare Research and Quality (AHRQ) contract HHSA-290-2007-10061 I.

Role of the Sponsors: The AHRQ participated in formulating key question and reviewed planned methods and data analyses, as well as interim and final evidence reports. The AHRQ had no role in the study selection, quality ratings, interpretation, or synthesis of the evidence.

Disclaimer: No statement in this article should be construed as an official position of the AHRQ or of the US Department of Health and Human Services.

Gould  MK, Garcia  DA, Wren  SM,  et alAmerican College of Chest Physicians.  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. Chest. 2012141(2)(suppl):e227S-e277S. doi:10.1378/chest.11-2297.
PubMed   |  Link to Article
Hamad  GG, Bergqvist  D.  Venous thromboembolism in bariatric surgery patients: an update of risk and prevention. Surg Obes Relat Dis. 20073(1):97-102.
PubMed   |  Link to Article
Borch  KH, Braekkan  SK, Mathiesen  EB,  et al.  Abdominal obesity is essential for the risk of venous thromboembolism in the metabolic syndrome: the Tromsø study. J Thromb Haemost. 20097(5):739-745.
PubMed   |  Link to Article
Ageno  W, Becattini  C, Brighton  T, Selby  R, Kamphuisen  PW.  Cardiovascular risk factors and venous thromboembolism: a meta-analysis. Circulation. 2008117(1):93-102.
PubMed   |  Link to Article
Cook  D, Douketis  J, Meade  M,  et al.  Critical care: venous thromboembolism and bleeding in critically ill patients with severe renal insufficiency receiving dalteparin thromboprophylaxis: prevalence, incidence and risk factors. Crit Care. 200812(2):R32. doi:10.1186/cc6810.
PubMed   |  Link to Article
Pryor  HI  II, Singleton  A, Lin  E, Lin  P, Vaziri  K.  Practice patterns in high-risk bariatric venous thromboembolism prophylaxis. Surg Endosc. 201327(3):843-848.
PubMed   |  Link to Article
Singh S, Haut ER, Brotman DJ, et al. Comparative Effectiveness of Pharmacologic and Mechanical Prophylaxis of Venous Thromboembolism Among Special Populations: Evidence Report/Technology Assessment. Washington, DC: 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. 199852(6):377-384.
PubMed   |  Link to Article
AHRQ. Methods Guide for Effectiveness and Comparative Effectiveness Reviews. Rockville, MD: Agency for Healthcare Research and Quality 2008. http://www.ncbi.nlm.nih.gov/books/NBK47095/. Accessed September 1, 2011.
Birkmeyer  NJ, Finks  JF, Carlin  AM,  et alMichigan Bariatric Surgery Collaborative.  Comparative effectiveness of unfractionated and low-molecular-weight heparin for prevention of venous thromboembolism following bariatric surgery. Arch Surg. 2012147(11):994-998.
PubMed   |  Link to Article
Birkmeyer  NJ, Finks  JF, English  WJ,  et alMichigan Bariatric Surgery Collaborative.  Risks and benefits of prophylactic inferior vena cava filters in patients undergoing bariatric surgery [published online February 8, 2013]. J Hosp Med. doi:10.1002/jhm.2013.
PubMed
Birkmeyer  NJ, Share  D, Baser  O,  et alMichigan Bariatric Surgery Collaborative.  Preoperative placement of inferior vena cava filters and outcomes after gastric bypass surgery. Ann Surg. 2010252(2):313-318.
PubMed   |  Link to Article
Scholten  DJ, Hoedema  RM, Scholten  SE.  A comparison of two different prophylactic dose regimens of low molecular weight heparin in bariatric surgery. Obes Surg. 200212(1):19-24.
PubMed   |  Link to Article
Raftopoulos  I, Martindale  C, Cronin  A, Steinberg  J.  The effect of extended post-discharge chemical thromboprophylaxis on venous thromboembolism rates after bariatric surgery: a prospective comparison trial. Surg Endosc. 200822(11):2384-2391.
PubMed   |  Link to Article
Overby  DW, Kohn  GP, Cahan  MA,  et al.  Risk-group targeted inferior vena cava filter placement in gastric bypass patients. Obes Surg. 200919(4):451-455.
PubMed   |  Link to Article
Ojo  P, Asiyanbola  B, Valin  E, Reinhold  R.  Post discharge prophylactic anticoagulation in gastric bypass patient—how safe? Obes Surg. 200818(7):791-796.
PubMed   |  Link to Article
Obeid  FN, Bowling  WM, Fike  JS, Durant  JA.  Efficacy of prophylactic inferior vena cava filter placement in bariatric surgery. Surg Obes Relat Dis. 20073(6):606-610.
PubMed   |  Link to Article
Hamad  GG, Choban  PS.  Enoxaparin for thromboprophylaxis in morbidly obese patients undergoing bariatric surgery: findings of the prophylaxis against VTE outcomes in bariatric surgery patients receiving enoxaparin (PROBE) study. Obes Surg. 200515(10):1368-1374.
PubMed   |  Link to Article
Gargiulo  NJ  III, Veith  FJ, Lipsitz  EC, Suggs  WD, Ohki  T, Goodman  E.  Experience with inferior vena cava filter placement in patients undergoing open gastric bypass procedures. J Vasc Surg. 200644(6):1301-1305.
PubMed   |  Link to Article
Eriksson  S, Backman  L, Ljungström  KG.  The incidence of clinical postoperative thrombosis after gastric surgery for obesity during 16 years. Obes Surg. 19977(4):332-336.
PubMed   |  Link to Article
Brasileiro  AL, Miranda  F  Jr, Ettinger  JE,  et al.  Incidence of lower limbs deep vein thrombosis after open and laparoscopic gastric bypass: a prospective study. Obes Surg. 200818(1):52-57.
PubMed   |  Link to Article
Borkgren-Okonek  MJ, Hart  RW, Pantano  JE,  et al.  Enoxaparin thromboprophylaxis in gastric bypass patients: extended duration, dose stratification, and antifactor Xa activity. Surg Obes Relat Dis. 20084(5):625-631.
PubMed   |  Link to Article
Singh  K, Podolsky  ER, Um  S,  et al.  Evaluating the safety and efficacy of BMI-based preoperative administration of low-molecular-weight heparin in morbidly obese patients undergoing Roux-en-Y gastric bypass surgery. Obes Surg. 201222(1):47-51.
PubMed   |  Link to Article
Li  W, Gorecki  P, Semaan  E, Briggs  W, Tortolani  AJ, D’Ayala  M.  Concurrent prophylactic placement of inferior vena cava filter in gastric bypass and adjustable banding operations in the Bariatric Outcomes Longitudinal Database. J Vasc Surg. 201255(6):1690-1695.
PubMed   |  Link to Article
Kothari  SN, Lambert  PJ, Mathiason  MA.  A comparison of thromboembolic and bleeding events following laparoscopic gastric bypass in patients treated with prophylactic regimens of unfractionated heparin or enoxaparin. Am J Surg. 2007194:709-711.
Link to Article
ASBMS position statement on prophylactic measures to reduce the risk of venous thromboembolism in bariatric surgery patients. Clinical Issues Committee of the American Society for Metabolic and Bariatric Surgery website. 2007. http://s3.amazonaws.com/publicASMBS/GuidelinesStatements/PositionStatement/vte_statement.pdf. Accessed December 15, 2012.
Becattini  C, Agnelli  G, Manina  G, Noya  G, Rondelli  F.  Venous thromboembolism after laparoscopic bariatric surgery for morbid obesity: clinical burden and prevention. Surg Obes Relat Dis. 20128(1):108-115.
PubMed   |  Link to Article

Figures

Place holder to copy figure label and caption
Figure 1.
Flow Diagram of Studies Included in the Systematic Review

HIT indicates heparin-induced thrombocytopenia and VTE, venous thromboembolism. *Total exceeds the number in the exclusion box because reviewers were allowed to mark more than 1 reason for exclusion.

Graphic Jump Location
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Figure 2.
Relative Risk (RR) Meta-analysis of inferior Vena Cava Filters (IVCFs) in Preventing Pulmonary Embolism in Patients Undergoing Bariatric Surgery

The shaded box sizes are proportional to the weight of each study blue diamond shows the CI of the pooled effect size. Black bars denote CIs for individual studies, and dotted line indicates the pooled effect estimate.

Graphic Jump Location
Place holder to copy figure label and caption
Figure 3.
Relative Risk (RR) Meta-analysis of Inferior Vena Cava Filters (IVCFs) and Deep Vein Thrombosis in Patients Undergoing Bariatric Surgery
Graphic Jump Location
Place holder to copy figure label and caption
Figure 4.
Relative Risk (RR) Meta-analysis of Inferior Vena Cava Filters (IVCFs) and Mortality in Patients Undergoing Bariatric Surgery
Graphic Jump Location

Tables

Table Graphic Jump LocationTable 1.  Characteristics of Studies of Inferior Vena Cava Filters Among Patients Undergoing Bariatric Surgery
Table Graphic Jump LocationTable 2.  Characteristics of Studies of Pharmacologic Comparisons Among Patients Undergoing Bariatric Surgery
Table Graphic Jump LocationTable 3.  Venous Thromboembolism Outcomes Among Patients Undergoing Bariatric Surgery Who Received Inferior Vena Cava Filters vs Control
Table Graphic Jump LocationTable 4.  Venous Thromboembolism Outcomes Among Bariatric Surgery Patients Undergoing Pharmacologic Prophylaxis
Table Graphic Jump LocationTable 5.  Safety Profile of Pharmacologic Interventions to Prevent Venous Thromboembolism in Bariatric Surgical Patients
Table Graphic Jump LocationTable 6.  Body of Evidence for IVCF vs Controls for the Prevention of PE in Patients Undergoing Bariatric Surgery1
Table Graphic Jump LocationTable 7.  Body of Evidence for Pharmacologic Prophylaxis for the Prevention of Venous Thromboembolism in Patients Undergoing Bariatric Surgery

References

Gould  MK, Garcia  DA, Wren  SM,  et alAmerican College of Chest Physicians.  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. Chest. 2012141(2)(suppl):e227S-e277S. doi:10.1378/chest.11-2297.
PubMed   |  Link to Article
Hamad  GG, Bergqvist  D.  Venous thromboembolism in bariatric surgery patients: an update of risk and prevention. Surg Obes Relat Dis. 20073(1):97-102.
PubMed   |  Link to Article
Borch  KH, Braekkan  SK, Mathiesen  EB,  et al.  Abdominal obesity is essential for the risk of venous thromboembolism in the metabolic syndrome: the Tromsø study. J Thromb Haemost. 20097(5):739-745.
PubMed   |  Link to Article
Ageno  W, Becattini  C, Brighton  T, Selby  R, Kamphuisen  PW.  Cardiovascular risk factors and venous thromboembolism: a meta-analysis. Circulation. 2008117(1):93-102.
PubMed   |  Link to Article
Cook  D, Douketis  J, Meade  M,  et al.  Critical care: venous thromboembolism and bleeding in critically ill patients with severe renal insufficiency receiving dalteparin thromboprophylaxis: prevalence, incidence and risk factors. Crit Care. 200812(2):R32. doi:10.1186/cc6810.
PubMed   |  Link to Article
Pryor  HI  II, Singleton  A, Lin  E, Lin  P, Vaziri  K.  Practice patterns in high-risk bariatric venous thromboembolism prophylaxis. Surg Endosc. 201327(3):843-848.
PubMed   |  Link to Article
Singh S, Haut ER, Brotman DJ, et al. Comparative Effectiveness of Pharmacologic and Mechanical Prophylaxis of Venous Thromboembolism Among Special Populations: Evidence Report/Technology Assessment. Washington, DC: 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. 199852(6):377-384.
PubMed   |  Link to Article
AHRQ. Methods Guide for Effectiveness and Comparative Effectiveness Reviews. Rockville, MD: Agency for Healthcare Research and Quality 2008. http://www.ncbi.nlm.nih.gov/books/NBK47095/. Accessed September 1, 2011.
Birkmeyer  NJ, Finks  JF, Carlin  AM,  et alMichigan Bariatric Surgery Collaborative.  Comparative effectiveness of unfractionated and low-molecular-weight heparin for prevention of venous thromboembolism following bariatric surgery. Arch Surg. 2012147(11):994-998.
PubMed   |  Link to Article
Birkmeyer  NJ, Finks  JF, English  WJ,  et alMichigan Bariatric Surgery Collaborative.  Risks and benefits of prophylactic inferior vena cava filters in patients undergoing bariatric surgery [published online February 8, 2013]. J Hosp Med. doi:10.1002/jhm.2013.
PubMed
Birkmeyer  NJ, Share  D, Baser  O,  et alMichigan Bariatric Surgery Collaborative.  Preoperative placement of inferior vena cava filters and outcomes after gastric bypass surgery. Ann Surg. 2010252(2):313-318.
PubMed   |  Link to Article
Scholten  DJ, Hoedema  RM, Scholten  SE.  A comparison of two different prophylactic dose regimens of low molecular weight heparin in bariatric surgery. Obes Surg. 200212(1):19-24.
PubMed   |  Link to Article
Raftopoulos  I, Martindale  C, Cronin  A, Steinberg  J.  The effect of extended post-discharge chemical thromboprophylaxis on venous thromboembolism rates after bariatric surgery: a prospective comparison trial. Surg Endosc. 200822(11):2384-2391.
PubMed   |  Link to Article
Overby  DW, Kohn  GP, Cahan  MA,  et al.  Risk-group targeted inferior vena cava filter placement in gastric bypass patients. Obes Surg. 200919(4):451-455.
PubMed   |  Link to Article
Ojo  P, Asiyanbola  B, Valin  E, Reinhold  R.  Post discharge prophylactic anticoagulation in gastric bypass patient—how safe? Obes Surg. 200818(7):791-796.
PubMed   |  Link to Article
Obeid  FN, Bowling  WM, Fike  JS, Durant  JA.  Efficacy of prophylactic inferior vena cava filter placement in bariatric surgery. Surg Obes Relat Dis. 20073(6):606-610.
PubMed   |  Link to Article
Hamad  GG, Choban  PS.  Enoxaparin for thromboprophylaxis in morbidly obese patients undergoing bariatric surgery: findings of the prophylaxis against VTE outcomes in bariatric surgery patients receiving enoxaparin (PROBE) study. Obes Surg. 200515(10):1368-1374.
PubMed   |  Link to Article
Gargiulo  NJ  III, Veith  FJ, Lipsitz  EC, Suggs  WD, Ohki  T, Goodman  E.  Experience with inferior vena cava filter placement in patients undergoing open gastric bypass procedures. J Vasc Surg. 200644(6):1301-1305.
PubMed   |  Link to Article
Eriksson  S, Backman  L, Ljungström  KG.  The incidence of clinical postoperative thrombosis after gastric surgery for obesity during 16 years. Obes Surg. 19977(4):332-336.
PubMed   |  Link to Article
Brasileiro  AL, Miranda  F  Jr, Ettinger  JE,  et al.  Incidence of lower limbs deep vein thrombosis after open and laparoscopic gastric bypass: a prospective study. Obes Surg. 200818(1):52-57.
PubMed   |  Link to Article
Borkgren-Okonek  MJ, Hart  RW, Pantano  JE,  et al.  Enoxaparin thromboprophylaxis in gastric bypass patients: extended duration, dose stratification, and antifactor Xa activity. Surg Obes Relat Dis. 20084(5):625-631.
PubMed   |  Link to Article
Singh  K, Podolsky  ER, Um  S,  et al.  Evaluating the safety and efficacy of BMI-based preoperative administration of low-molecular-weight heparin in morbidly obese patients undergoing Roux-en-Y gastric bypass surgery. Obes Surg. 201222(1):47-51.
PubMed   |  Link to Article
Li  W, Gorecki  P, Semaan  E, Briggs  W, Tortolani  AJ, D’Ayala  M.  Concurrent prophylactic placement of inferior vena cava filter in gastric bypass and adjustable banding operations in the Bariatric Outcomes Longitudinal Database. J Vasc Surg. 201255(6):1690-1695.
PubMed   |  Link to Article
Kothari  SN, Lambert  PJ, Mathiason  MA.  A comparison of thromboembolic and bleeding events following laparoscopic gastric bypass in patients treated with prophylactic regimens of unfractionated heparin or enoxaparin. Am J Surg. 2007194:709-711.
Link to Article
ASBMS position statement on prophylactic measures to reduce the risk of venous thromboembolism in bariatric surgery patients. Clinical Issues Committee of the American Society for Metabolic and Bariatric Surgery website. 2007. http://s3.amazonaws.com/publicASMBS/GuidelinesStatements/PositionStatement/vte_statement.pdf. Accessed December 15, 2012.
Becattini  C, Agnelli  G, Manina  G, Noya  G, Rondelli  F.  Venous thromboembolism after laparoscopic bariatric surgery for morbid obesity: clinical burden and prevention. Surg Obes Relat Dis. 20128(1):108-115.
PubMed   |  Link to Article

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