Current Indications for Preoperative Inferior Vena Cava Filter Insertion in Patients Undergoing Surgery for Morbid Obesity

Efficacy and safety of pre-operative insertion of inferior vena cava filter in patients undergoing bariatric surgery: a systematic review

Prophylactic placement of inferior vena cava (IVC) filters prior to performing bariatric surgery is an intervention of unclear safety and efficacy with disagreement between current practice guidelines. To better characterize the risk and benefit of IVC filter insertion prior to bariatric surgery based on the current evidence. A systematic review of the literature of patients with prophylactic IVC filter insertion prior to bariatric surgery was performed and 32 studies were identified for inclusion into the review, of which none were randomized controlled trials. Meta-analysis was performed including the high-quality included studies. Seven high quality studies reported thrombotic events in patients undergoing bariatric surgery who had an IVCF and a control group which allowed for meta-analysis. The pooled odds ratio of venous thrombotic events in the IVC filter population versus the group without IVC filters was 1.57 (95%CI 0.89, 2.76). Among high quality studies 5 reported major bleeding with a rate of 0.76% and 6 reported on IVC filter complications with a rate of 0.67%. Overall no significant reduction in the rate of venous thrombosis was found with prophylactic IVC filter insertion. Use of IVC filters for prophylaxis remains a concern given the lack of clear efficacy in this setting and a small but present complication risk.

Deep vein thrombosis prophylaxis: Are we overdoing? An Asian survey on trends in bariatric surgery with a systematic review of literature

Background:

Obesity is a risk factor for deep vein thrombosis (DVT) and venous thromboembolism (VTE). VTE is the most common cause of mortality in patients undergoing bariatric surgery. There is considerable variation in practice regarding methods, dosages and duration of prophylaxis in this patient population. Most of the literature is based on Western patients and specific guidelines for Asians do not exist.

Methods:

We conducted a web-based survey amongst 11 surgeons from high-volume centres in Asia regarding their DVT prophylaxis measures in patients undergoing bariatric surgery. We collected and analysed the data.

Results:

The reported incidence of DVT and VTE ranged from 0% to 0.2%. Most surgeons (63.64%) preferred to use both mechanical and chemoprophylaxis with low-molecular-weight heparin being the most preferred form of chemoprophylaxis (81.82%). There was an equal distribution of weight-based, body mass index-based and fixed-dose regimens. Duration of chemoprophylaxis ranged from 3–5 days after surgery to 2 weeks after surgery. For high-risk patients, 60% surgeons preferred to start chemoprophylaxis at least 1 week before surgery. Routine use of inferior vena cava filters in high-risk patients was not preferred with some surgeons adopting a selective use (36.36%).

Conclusion:

The purpose of this survey was to understand the trends in DVT prophylaxis amongst different high-volume bariatric centres in Asia and to relate the same with the existing literature on the different steps in prophylaxis. There is, however, a need for consensus guidelines for DVT prophylaxis in Asian obese.

Obesity: physiologic changes and implications for preoperative management

The proportion of patients defined as obese continues to grow in many westernized nations, particularly the United States (USA). This trend has shifted the perioperative management of obese patients into the realm of routine care. As obese patients present for all types of procedures, it is crucial for anesthesiologists, surgeons, internists, and perioperative health care providers alike to have a firm understanding of their altered multi-organ physiology in order to safely prepare the obese patient for an operation. A careful preoperative evaluation may also serve to identify risk factors for postoperative adverse events. Subsequently, preoperative measures may be implemented to mitigate these complications. In this manuscript we address the major considerations for the preoperative evaluation of the severely obese patient.

Risks and benefits of prophylactic inferior vena cava filters in patients undergoing bariatric surgery

BACKGROUND

The United States Food and Drug Administration recently issued a warning about adverse events in patients receiving inferior vena cava (IVC) filters.

OBJECTIVE

To assess relationships between IVC filter insertion and complications while controlling for differences in baseline patient characteristics and medical venous thromboembolism prophylaxis.

DESIGN

Propensity-matched cohort study.

SETTING

The prospective, statewide, clinical registry of the Michigan Bariatric Surgery Collaborative.

PATIENTS

Bariatric surgery patients (n=35,477) from 32 hospitals during the years 2006 through 2012.

INTERVENTION

Prophylactic IVC filter insertion.

MEASUREMENTS

Outcomes included the occurrence of complications (pulmonary embolism, deep vein thrombosis, and overall combined rates of complications by severity) within 30 days of bariatric surgery.

RESULTS

There were no significant differences in baseline characteristics among the 1,077 patients with IVC filters and in 1,077 matched control patients. Patients receiving IVC filters had higher rates of pulmonary embolism (0.84% vs 0.46%; odds ratio [OR], 2.0; 95% confidence interval [CI], 0.6-6.5; P=0.232), deep vein thrombosis (1.2% vs 0.37%; OR, 3.3; 95% CI, 1.1-10.1; P=0.039), venous thromboembolism (1.9% vs 0.74%; OR, 2.7; 95% CI, 1.1-6.3, P=0.027), serious complications (5.8% vs 3.8%; OR, 1.6; 95% CI, 1.0-2.4; P=0.031), permanently disabling complications (1.2% vs 0.37%; OR, 4.3; 95% CI, 1.2-15.6; P=0.028), and death (0.7% vs 0.09%; OR, 7.0; 95% CI, 0.9-57.3; P=0.068). Of the 7 deaths among patients with IVC filters, 4 were attributable to pulmonary embolism and 2 to IVC thrombosis/occlusion.

CONCLUSIONS

We have identified no benefits and significant risks to the use of prophylactic IVC filters among bariatric surgery patients and believe that their use should be discouraged.

The Role for Prophylaxis Inferior Vena Cava Filters in Patients Undergoing Bariatric Surgery: Replacing Anecdote with Evidence

The number of patients choosing surgical alternatives for weight reduction continues to increase. Despite common thromboembolic preventive methods, which include perioperative subcutaneous heparin injections, early mobilization, and sequential compression devices, postoperative deep vein thrombosis/pulmonary embolism remains a devastating complication after bariatric surgery. The role prophylactic inferior vena cava (IVC) filters may play in bariatric surgery remains controversial, and this article aims to address the risks and benefits of prophylactic IVC filters in high-risk bariatric patients and suggest an evidence-based algorithm for their use.

Complications of laparoscopic Roux-en-Y gastric bypass

Despite the well-documented safety of laparoscopic RYGB, several short-term and long-term complications, with varying degrees of morbidity and mortality risk, are known to occur. Bariatric surgeons, all too familiar with these complications, should be knowledgeable in risk-reduction strategies to minimize the incidence of complication occurrence and recurrence. Bariatric and nonbariatric surgeons who evaluate and treat abdominal pain should be familiar with these complications to facilitate early recognition and intervention, thereby minimizing the associated morbidity and mortality.

Difficulties in managing the surgical patient who is morbidly obese

Managing patients who are morbidly obese in the intensive care unit is associated with a variety of problems uncommonly experienced with the those who are not morbidly obese. Clinicians experience a myriad of unique problems and circumstances, from the need for special beds and lifts to unusual and unknown volumes of distribution resulting in unclear drug dosing. This review examines several issues including sedation, invasive monitoring, venous thromboembolism prophylaxis, surgical infections, nutritional support, and other complications that may be of particular importance to the critically ill patient who is morbidly obese. In many cases, care is altered based on the complicating issues surrounding morbid obesity. In other cases, the presence of obesity suggests no alterations in our routine critical care delivery. A comprehensive review of the literature is undertaken, data are critically considered, and overall opinion is rendered based on the available peer-reviewed literature. In many cases, data are not available that address the specific patient population in question, so related papers (like gastric bypass data) are considered. Many issues do not have definitive answers based on randomized controlled trials, and much is left to treating clinician opinion and local practice patterns. Where good data exist, however, one should consider carefully and individually deviation from the evidence-based approach.

Preoperative placement of inferior vena cava filters and outcomes after gastric bypass surgery

OBJECTIVE

To assess relationships between inferior vena cava (IVC) filter placement and complications within 30 days of gastric bypass surgery.

SUMMARY OF BACKGROUND DATA

IVC filters are increasingly being used as prophylaxis against postoperative pulmonary embolism in patients undergoing bariatric surgery, despite a lack of evidence of effectiveness.

METHODS

On the basis of data from a prospective clinical registry involving 20 Michigan hospitals, we identified 6376 patients undergoing gastric bypass surgery between 2006 and 2008. We then assessed relationships between IVC filter placement and complications within 30 days of surgery. We used propensity scores and fixed effects logistic regression to control for potential selection bias.

RESULTS

A total of 542 gastric bypass patients (8.5%) underwent preoperative IVC filter placement, most of whom (65%) had no history of venous thromboembolism. The use of IVC filters for gastric bypass patients varied widely across hospitals (range, 0%-34%). IVC filter patients did not have reduced rates of postoperative venous thromboembolism (adjusted odds ratio [OR], = 1.28; 95% confidence interval [CI], 0.51-3.21), serious complications (adjusted OR, = 1.40; 95% CI, 0.91-2.16), or death/permanent disability (adjusted OR, = 2.49; 95% CI, 0.99-6.26). More than half (57%) of the IVC filter patients in the latter group had a fatal pulmonary embolism or complications directly related to the IVC filter itself, including filter migration or thrombosis of the vena cava. In subgroup analyses, we were unable to identify any patient group for whom IVC filters were associated with improved outcomes.

CONCLUSIONS

Prophylactic IVC filters for gastric bypass surgery do not reduce the risk of pulmonary embolism and may lead to additional complications.

Inferior vena caval filter insertion prior to bariatric surgery: a systematic review of the literature

Placement of inferior vena cava filters (IVCFs) is considered in many patients undergoing bariatric surgery. Their placement is driven by a high rate of pulmonary embolism (PE), uncertainty as to the effectiveness of pharmacologic prophylaxis, and a lack of alternate methods to prevent pulmonary embolism. We performed a systematic review of the literature to evaluate the evidence supporting placement of IVCFs in patients undergoing bariatric surgery. Eleven studies were identified; none were randomized trials. Descriptive analysis suggests that IVCFs reduced PE; however, the strength of this observation is tempered by the lack of use of effective forms of prophylaxis and the failure to account for complications of IVCF placement. We conclude, pending the results of controlled studies, that the use of IVCFs cannot be recommended for routine patients undergoing bariatric surgery.

Obesity and bariatric surgery

Laparoscopic Roux-en-Y gastric bypass and laparoscopic adjustable gastric banding are the most commonly performed weight reduction operations in the United States. Preoperative assessment and selection should be performed by a multidisciplinary team to obtain optimal results. The most devastating complication of bariatric surgery is leak, which can carry a high risk of mortality if not detected and treated expediently. New nationwide databases have been developed to monitor outcomes and facilitate better understanding of the mechanisms of bariatric surgery. New horizons for the advancement of bariatric surgery are in the realm of surgery in adolescent and geriatric populations, the use of weight-loss surgery in lower body mass index (<35 kg/m(2)) populations, and the use of surgery to cure the comorbidities of obesity.

Best practice updates for nursing care in weight loss surgery

The objective of this study is to update evidence-based best practice guidelines for nursing in weight loss surgery (WLS). We performed a systematic search of English-language literature on WLS and perioperative nursing, postoperative, anesthesia, and discharge published between April 2004 and May 2007 in MEDLINE, CINHAL and the Cochrane Library. Key words were used to narrow the search for a selective review of abstracts, retrieval of full articles, and grading of evidence according to systems used in established evidence-based models. From these, we developed evidence-based best practice recommendations from the most recent literature on nursing in WLS. We identified >54 papers; the most relevant were reviewed in detail. Regular updates of evidence-based recommendations for best practices in WLS nursing are required to address advances in surgery and anesthesiology, as well as changes in the demographics and levels of obesity in WLS patients. Key factors in patient safety include staff education, comprehensive admission assessment, patient education, careful preoperative surveillance and postoperative care, and long-term discharge follow-up.

American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery medical guidelines for clinical practice for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient

American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery Medical Guidelines for Clinical Practice are systematically developed statements to assist health-care professionals in medical decision making for specific clinical conditions. Most of the content herein is based on literature reviews. In areas of uncertainty, professional judgment was applied. These guidelines are a working document that reflects the state of the field at the time of publication. Because rapid changes in this area are expected, periodic revisions are inevitable. We encourage medical professionals to use this information in conjunction with their best clinical judgment. The presented recommendations may not be appropriate in all situations. Any decision by practitioners to apply these guidelines must be made in light of local resources and individual patient circumstances. The American Society for Parenteral & Enteral Nutrition fully endorses sections of these guidelines that address the metabolic and nutritional management of the bariatric surgical patient.

ASH evidence-based guidelines: what is the role of inferior vena cava filters in the perioperative prevention of venous thromboembolism in bariatric surgery patients?

A 38-year-old morbidly obese male (BMI > 50 kg/m(2)) presents for an elective gastric bypass surgery. He has no personal or family history of venous thromboembolism or hypercoaguability. You are asked by his primary team whether he should receive a retrievable inferior vena cava filter preoperatively for venous thromboembolism prophylaxis.

Status of venous thromboembolism prophylaxis among bariatric surgeons: have we changed our practice during the past decade?

BACKGROUND

Venous thromboembolism (VTE) is considered one of the principal causes of morbidity and mortality in patients requiring bariatric surgery. A survey to all members of the American Society for Metabolic and Bariatric Surgery was conducted in 1998 and published in 2000 in the journal "Obesity Surgery."

METHODS

A survey was repeated to all physician members of the American Society for Metabolic and Bariatric Surgery to determine the current practices for VTE prophylaxis. The results were compared with those of the previous study.

RESULTS

Of the members, 35% completed the survey for a total of 332 responses. The number of cases annually per surgeon almost doubled since 1998 (145 versus 85). Laparoscopic gastric bypass has replaced open gastric bypass as the most common procedure performed, followed by laparoscopic gastric banding as the second most common procedure. Most surgeons (95%) use chemical prophylaxis to prevent VTE, but almost 60% preferred low-molecular-weight heparin compared with 13% in 1998. More than 60% of bariatric surgeons discharged their patients with chemical prophylaxis compared with 12% in 1998. Inferior vena cava filters for prophylaxis are considered by 55% compared with only 7% in 1998. The incidence of reported deep vein thrombosis was significantly lower in 2007 (2.635 versus .93), as was the incidence of pulmonary embolism (.95% versus .75%). Almost 50% of surgeons still reported > or =1 fatality because of VTE complications.

CONCLUSION

Chemical prophylaxis for VTE with some type of heparin is the standard of care for patients undergoing bariatric surgery. Low-molecular-weight heparin is now used by two thirds of the respondents to this survey. Most surgeons who responded to the survey discharged their patients home with heparin, and many consider the use of inferior vena cava filters for VTE prophylaxis. Our findings support the American Society for Metabolic Bariatric Surgery position statement regarding VTE prophylaxis in this patient population. Research is necessary to establish the role of inferior vena cava filters, discharging patients with chemoprophylaxis and to determine the adequate dosage and duration of prophylaxis.

American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery Medical Guidelines for Clinical Practice for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient

American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery Medical Guidelines for Clinical Practice are systematically developed statements to assist healthcare professionals in medical decision making for specific clinical conditions. Most of the content herein is based on literature reviews. In areas of uncertainty, professional judgment was applied. These guidelines are a working document that reflects the state of the field at the time of publication. Because rapid changes in this area are expected, periodic revisions are inevitable. We encourage medical professionals to use this information in conjunction with their best clinical judgment. The presented recommendations may not be appropriate in all situations. Any decision by practitioners to apply these guidelines must be made in light of local resources and individual patient circumstances. The American Society for Parenteral & Enteral Nutrition fully endorses sections of these guidelines that address the metabolic and nutritional management of the bariatric surgical patient.

Inferior vena cava syndrome and morbid obesity

A case is reported of inferior vena cava syndrome in a patient with extreme obesity (BMI: >70 kg/m(2)), treated at a public hospital. The inferior vena cava obstruction was diagnosed during an attempt at inferior vena cava filter percutaneous insertion, in prebariatric surgery period. The diagnosis occurred after a hepatic scintillography, and was confirmed with a femoral venography and celiac trunk arteriography. The patient underwent a biliopancreatic diversion-duodenal switch and has lost weight. A venography 7 months after the surgery did not show any inferior vena cava rechanneling evidence.

Preoperative placement of retreivable inferior vena cava filters in bariatric surgery

BACKGROUND

Postoperative pulmonary embolism (PE) is a major source of mortality after bariatric surgery. In conjunction with pharmacologic thromboprophylaxis, lower extremity pneumatic compression devices, and early ambulation, preoperative placement of a retrievable inferior vena cava (IVC) filter may reduce the risk of thromboembolic complications.

METHODS

From June 2003 to October 2005, 652 patients underwent mini-open Roux-en-Y gastric bypass. Of the 652 patients, 557 were women and 95 were men. The mean patient age was 40.7 +/- 3.6 years (range 18-67), mean body mass index was 44.7 +/- 4.6 kg/m(2) (range 35-78), and mean operative time was 60.2 +/- 5.3 minutes (range 42-79). The high-risk PE group consisted of 27 patients (4.1%; 9 men and 18 women) who received preoperative retrievable IVC filters placed by the interventional radiology staff 2 hours before bypass surgery. Their mean age was 47 +/- 4.4 years (range 31-66) and mean body mass index 48.7 +/- 4.2 kg/m(2) (range 38-75). The indications for filter placement were previous deep vein thrombosis/PE, thrombophlebitis, a hypercoagulable state, pulmonary hypertension, an inability to ambulate, a body mass index >65 kg/m(2), and the presence of severe sleep apnea. The filters were removed 18.2 +/- 2 days (range 15-21) postoperatively.

RESULTS

All 27 patients who received a prophylactic IVC filter tolerated the procedure well, without major complications. One retrievable filter was not removed because of prolonged hospitalization secondary to small bowel obstruction. No thromboembolic complications occurred in this high-risk group.

CONCLUSION

Preoperative placement of retrievable IVC filters is a safe measure for the prophylaxis of PE in high-risk bariatric patients. The filters can be placed efficiently just before surgery, and most filters can be removed 2-3 weeks postoperatively. Additional investigation is necessary to prove the effectiveness of retrievable IVC filters in bariatric surgery.

The use of intravascular ultrasound imaging to improve use of inferior vena cava filters in a high-risk bariatric population

OBJECTIVE

Pulmonary embolism is the leading cause of death after gastric bypass procedures for obesity, approximating 0.5% to 4%. All bariatric patients, but especially the super-obese, which have a body mass index (BMI) >50 kg/m(2), are at significant risk for postoperative venous thromboembolism (VTE). Visualization and weight limitations of fluoroscopy tables exclude most bariatric and all super-obese patients from inferior vena cava (IVC) filter placement using fluoroscopy. Intravascular ultrasound (IVUS)-guided IVC filter placement is the only modality that allows these high-risk patients to have an IVC filter placed.

METHODS

Hospital and outpatient records of the 494 patients who underwent gastric bypass procedures from January 1, 2004, to May 31, 2006, were reviewed. All patients who had concurrent IVC filter placement with the use of IVUS guidance were selected. Comorbidities, outcomes, and complications were recorded.

RESULTS

We identified 27 patients with mean BMI of 70 +/- 3 kg/m(2); of these, 25 were super-obese (BMI >50 kg/m(2)). Procedures included five laparoscopic and 22 open gastric bypass operations. All patients underwent concurrent IVC filter placement using IVUS guidance. In addition to super-obesity, indications for IVC filter placement included history of VTE (n = 4), known hypercoagulable state (n = 2), and profound immobility (n = 21). Mean follow up was 293 +/- 40 days. Technical success rate was 96.3%. There were no catheter site complications. In one surviving patient, a nonfatal pulmonary embolism was detected by computed tomography 2 months postoperatively. Two patients died, and autopsy excluded VTE as the cause of death in both.

CONCLUSION

This study suggests efficacy of IVUS-guided IVC filter placement in preventing mortality from pulmonary embolism in high-risk bariatric patients, including the super-obese. IVUS-guided IVC filter placement can be safely performed with an excellent success rate in all bariatric patients, including the super-obese, who otherwise would not be candidates for IVC filter placement due to the limitations imposed by their large body habitus.

Efficacy of inferior vena cava filters in anticoagulated patients

BACKGROUND AND OBJECTIVES

The benefit of an inferior vena cava (IVC) filter in addition to standard anticoagulation regimens is unknown.

METHODS

We examined data for patients who received IVC filters with anticoagulation (AC-Filter) after an episode of venous thromboembolism (VTE) and compared them with data for those who received anticoagulation only (AC-Only). Outcome measures were new pulmonary embolism (PE), recurrent deep vein thrombosis (DVT), and mortality at 90 days and at 5 years. Demographic data included age, gender, and ethnicity/race, prior thromboembolic history, cancer, serum albumin, and time in therapeutic range. In addition, subsets matched for age, gender and race/ethnicity were examined in detail.

RESULTS

AC-Filter patients (n = 251), when compared to AC-Only patients (n = 1377), did not differ significantly with regard to gender or cancer status, but white males in general had better outcomes. AC-Filter patients were more likely to have had a previous history of PE or VTE (P < 0.001). In comparison to AC-Only patients, AC-Filter patients had lower mean serum albumin levels (3.1 +/- 0.8 vs. 3.6 +/-0.8 mg dL(-1), P < 0.001) and were older (65 +/- 16.1 years vs. 60 +/- 17.5 years, P < 0.001). After stratification according to previous history of PE or VTE prior to the index VTE event, no differences in the outcome measures of new PE, recurrent DVT or mortality were identified between groups, but patients with a prior history of PE from either group were more likely to have a new PE (hazard ratio 1.9, P < 0.001).

CONCLUSIONS

These data suggest that IVC filters may not provide any substantial additional benefit for patients who can tolerate anticoagulant therapy.

Inferior vena cava filter placement for pulmonary embolism risk reduction in super morbidly obese undergoing bariatric surgery

BACKGROUND

Pulmonary embolism (PE) is a leading cause of mortality after bariatric surgery. We evaluated inferior vena cava (IVC) filter use for PE risk reduction in high-risk super morbidly obese bariatric surgery patients.

METHODS

IVC filters were inserted according to the patient's risk factors, including immobility, previous deep venous thrombosis (DVT)/PE, venous stasis, and pulmonary compromise. All filters were placed concomitant to bariatric surgery and were placed through a right internal jugular vein access site. We analyzed the prospectively collected data from this cohort and evaluated the incidence of PE and complications.

RESULTS

Since April 2003, 41 patients (12 men and 29 women) with a mean age of 47.3 +/- 10.0 years and body mass index of 64.2 +/- 12 kg/m2 (range 47-105) underwent IVC filter placement. These and all other patients underwent standard DVT/PE risk reduction measures. All IVC filter patients had one or more significant risk factors for thromboembolic events. No instances of PE were documented, although 1 patient experienced DVT, and no immediate or late complications related to filter placement occurred. One patient, with a body mass index of 105 kg/m2, died secondary to rhabdomyolysis after an extended procedure. The average filter placement time was 34.3 +/- 9 minutes.

CONCLUSION

IVC filter placement for PE risk reduction is safe and feasible in the super morbidly obese. Our data have shown that the filters can be placed expeditiously and with minimal morbidity concomitant with bariatric surgery. In this limited series, IVC filter placement was associated with no PE. Additional studies are needed to confirm the efficacy of IVC filter placement for PE risk reduction and related mortality in the super morbidly obese.

Preoperative assessment and perioperative care of patients undergoing bariatric surgery

The prevalence of morbid obesity in the United States and worldwide is increasing at an alarming rate. The number of bariatric surgical procedures also has steadily increased during the past decade. This article reviews the published literature and current practice trends for preoperative workup and assessment of patients undergoing bariatric surgery.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Mini-gastric bypass in a patient homozygous for Factor V Leiden

A 42-year-old morbidly obese female, homozygous for Factor V Leiden, underwent mini-gastric bypass without complications. The recommendations for prophylaxis in this high-risk population are unclear and most likely involve a combination of pharmacologic and non-pharmacologic measures.

The inferior vena cava filter is effective in preventing fatal pulmonary embolus after hip and knee arthroplasties

Thromboembolic disease is a relatively common and potentially devastating complication of joint arthroplasty. Mechanical and chemical prophylaxes are effective in reducing the incidence of this complication. Inferior vena cava (IVC) filters have been used to prevent the propagation and/or migration of venous emboli into the pulmonary circulation. This article reports on a cohort of joint arthroplasty patients either with confirmed pulmonary embolism or at high risk of developing pulmonary emboli in whom an IVC filter was implanted. Using the institutional database, 95 joint arthroplasty patients who received an IVC filter were identified. The IVC filter was effective in preventing fatal pulmonary emboli in all patients. The IVC filter is a valuable and effective modality in preventing a fatal outcome of thromboembolism in patients with established thromboembolism.

Surgery for obesity: a review of the current state of the art and future directions

The number of patients undergoing surgery for the treatment of obesity, and the proportion of the health care budget dedicated to this health problem, is growing exponentially. There are several competing surgical approaches for the management of morbid obesity. We review the literature relating to four of these: gastric bypass, biliopancreatic diversion, gastric banding, and gastric pacing. Our review finds that while enhancing the malabsorptive activity of these procedures may induce an incremental increase in excess body weight loss, the proportion of patients who fail to lose more than 50% of their excess body weight is similar no matter how radical is the surgery performed. There is little guidance from the literature as to appropriate patient selection for the varying procedures, and anonymously reported registries have yet to show that patients who undergo bariatric surgery have enhanced longevity. To date, the bariatric surgical community has not conducted adequately powered randomized prospective trials to elucidate key elements of the surgical procedure such as optimal bypass length, to determine whether mixed operations are superior to those that offer intake restriction only, and to define what constitutes success after bariatric surgery. As a public health measure, bariatric surgery in the United States is being pursued in an irrational manner, being concentrated in areas where there are fewer morbidly obese patients, and used disproportionately among the population of white obese females.

Vena cava filters: an update

Venous thromboembolism is a major health problem that results in significant long-term complications and mortality. The management of venous thromboembolism is complex and can be particularly challenging when pharmacological therapy alone cannot be effectively utilized. Vena cava filters provide protection from pulmonary embolism for patients in whom therapeutic anticoagulation is contraindicated or inadequate. Recent innovations in caval interruption have included the use of alternative imaging modalities for filter insertion and the emergence of devices designed to allow temporary caval filtration. These developments have been accompanied by a controversial increase in the use of vena cava filters for prophylactic indications in the absence of venous thromboembolism. In addition to a brief historical perspective on caval filtration, this update reviews the indications for vena cava filter insertion, associated complications, methods of caval imaging and filter insertion and current FDA-approved devices.

Perioperative care of patients undergoing bariatric surgery

The epidemic of obesity in developed countries has resulted in patients with extreme (class III) obesity undergoing the full breadth of medical and surgical procedures. The popularity of bariatric surgery in the treatment of extreme obesity has raised awareness of the unique considerations in the care of this patient population. Minimizing the risk of perioperative complications that contribute to morbidity and mortality requires input from several clinical disciplines and begins with the preoperative assessment of the patient. Airway management, intravenous fluid administration, physiologic responses to pneumoperitoneum during laparoscopic procedures, and the risk of thrombotic complications and peripheral nerve injuries in extremely obese patients are among the factors that present special intraoperative challenges that affect postoperative recovery of the bariatric patient. Early recognition of perioperative complications and education of the patient regarding postoperative issues, including nutrition and vitamin supplementation therapy, can improve patient outcomes. A suitable physical environment and appropriate nursing and dietetic support provide a safe and dignified hospital experience. This article reviews the multidisciplinary management of extremely obese patients who undergo bariatric surgery at the Mayo Clinic.

Predictive factors of thromboembolic events in patients undergoing Roux-en-Y gastric bypass

BACKGROUND

Obesity is a major risk factor for postoperative deep venous thrombosis (DVT) and pulmonary embolism (PE). Identifying those patients at the greatest risk for DVT/PE is essential to prevent thromboembolic events among patients undergoing Roux-en-Y gastric bypass (RYGB) for clinically significant obesity. This aim of the study is to identify factors associated with an increased likelihood of developing DVT/PE after RYGB.

METHODS

Prospectively collected data from 660 consecutive patients who underwent RYGB were reviewed. Patients received perioperative prophylaxis with low molecular weight heparin and sequential compression devices. Diagnosis was based on clinical, radiologic, and/or necropsy findings. Patients with and without postoperative DVT/PE were compared using chi(2) and multivariate logistic regression analysis.

RESULTS

A total of 23 patients (3.5%) developed postoperative DVT/PE. Age > 50 years (P = .04), previous DVT/PE (P = .02), history of smoking (P < .01), revisional operation (P = .03), open RYGB (P = .02), and anastomotic leak (P < .0001) significantly increased the likelihood of developing DVT/PE. On the other hand, gender, body mass index > 50 kg/m(2) and history of sleep apnea, hypertension, diabetes, or myocardial infarction did not increase the likelihood of DVT/PE. Multivariate analysis revealed that age > 50 years (P = .04), postoperative anastomotic leak (P < .001), smoking (P < .01), and previous DVT/PE (P < .001) increased the likelihood of postoperative DVT/PE.

CONCLUSIONS

Age > 50 years, anastomotic leak, smoking, and history of DVT/PE all increase the likelihood of postoperative thromboembolic events in patients undergoing RYGB. Further preoperative screening and/or postoperative prophylaxis may be needed in this subset of high-risk patients.