Incidence of deep vein thrombosis in morbidly obese patients undergoing laparoscopic Roux-en-Y gastric bypass

Massive pulmonary embolism post sleeve gastrectomy treated with systemic thrombolytic: A case report

Prompt diagnosis and management of massive pulmonary embolism after bariatric surgery is crucial, but thrombolytic therapy may increase the risk of complications such as anastomotic leakage and bleeding. Individualized management is needed.

The Safety and Efficacy of Apixaban (Eliquis) in 5017 Post-bariatric Patients with 95.3% Follow-up: a Multicenter Study

BACKGROUND

Thromboprophylaxis in bariatric surgery is widely debated; however, few large articles evaluate treatment plans and their efficacy. Herein, we make the first large-scale report of the safety and efficacy of apixaban (Eliquis) for thrombus prevention following bariatric surgery.

PURPOSE

To evaluate the safety and efficacy of apixaban following bariatric surgery.

SETTING

Three private institutes, USA.

MATERIALS AND METHODS

Data from 5017 consecutive bariatric patients that were placed on postoperative apixaban for thromboprophylaxis were used for retrospective analysis. The dose prescribed to patients was 2.5 mg PO BID for a total of 30 days starting on day 3 postoperatively.

RESULTS

In total, of the 5017 patients, 59.7%, 31.2%, 4.4%, 2.5%, 1.8%, and 0.1% of the patients had undergone sleeve gastrectomy (SG), single-anastomosis duodeno-ileal bypass with SG (SADI-S), Roux-en-Y gastric bypass (RYGB), conversion from SG to SADI, small bowel reconstruction, and RYGB reversal, respectively. The 30-day follow-up rate was 95.3%. In total, 1.7% of patients experienced apixaban-related side effects. The most common side effects were menorrhagia and rash. Two (0.03%) side effects developed into Clavien-Dindo grade II complications. Overall, 10 (0.1%) patients experienced thromboembolic complications (five (0.09%) PVTs and five (0.09%) PEs). In each case, the protocol was not followed for extenuating circumstances. There were no deaths or thromboembolic events in cases where the protocol was able to be fully followed.

CONCLUSIONS

In conclusion, 30 days of postoperative apixaban appears to be safe and effective with minimal side effects while preventing thromboembolic events.

Dosage of Anticoagulants in Obesity: Recommendations Based on a Systematic Review

Anticoagulants are frequently used as thromboprophylaxis and in patients with atrial fibrillation (AF) or venous thromboembolism (VTE). While obesity rates are reaching epidemic proportions worldwide, the optimal dosage for obese patients has not been established for most anticoagulants, including low-molecular-weight heparin (LMWH), non-vitamin K antagonist oral anticoagulants (NOAC), and pentasaccharides (fondaparinux). The aim of the present systematic review was to summarize the current knowledge and provide recommendations on dosage of LMWH, NOAC, and fondaparinux in obese patients (body mass index [BMI] ≥ 30 kg/m² or body weight ≥ 100 kg). Based on a systematic search in PubMed and Embase, a total of 72 studies were identified. For thromboprophylaxis with LMWH in bariatric surgery (n = 20 studies), enoxaparin 40 mg twice daily, dalteparin 5,000 IE twice daily, or tinzaparin 75 IU/kg once daily should be considered for patients with BMI ≥ 40 kg/m². For thromboprophylaxis with LMWH in nonbariatric surgery and in medical inpatients (n = 8 studies), enoxaparin 0.5 mg/kg once or twice daily or tinzaparin 75 IU/kg once daily may be considered in obese patients. For treatment with LMWH (n = 18 studies), a reduced weight-based dose of enoxaparin 0.8 mg/kg twice daily should be considered in patients with BMI ≥ 40 kg/m², and no dose capping of dalteparin and tinzaparin should be applied for body weight < 140 kg. As regards NOAC, rivaroxaban, apixaban, or dabigatran may be used as thromboprophylaxis in patients with BMI < 40 kg/m² (n = 4 studies), whereas rivaroxaban and apixaban may be administered to obese patients with VTE or AF, including BMI > 40 kg/m², at standard fixed-dose (n = 20 studies). The limited available evidence on fondaparinux (n = 3 studies) indicated that the treatment dose should be increased to 10 mg once daily in patients weighing > 100 kg.

Missing something? A scoping review of venous thromboembolic events and their associations with bariatric surgery. Refining the evidence base

Background

Venous thromboembolic events (VTE) post-bariatric surgery (BS) lead to morbidity and mortality.

Methods

This scoping review assessed whether reported VTE post-BS could be under/over-estimated; suggested a possible number of VTE post-BS; appraised whether VTE are likely to decrease/increase; examined BS as risk/protective factor for VTE; and mapped the gaps, proposing potential solutions.

Results

VTE appears under-estimated due to: identification/coding of BS and VTE; reporting of exposure (BS); and reporting of outcomes (VTE). The review proposes a hypothetical calculation of VTE post-BS. VTE are unlikely to decrease soon. BS represents risk and protection for VTE. Better appreciation of VTE-BS relationships requires longer-term strategies.

Conclusion

VTE are underestimated. Actions are required for understanding the VTE-BS relationships to in order to crease VTE by better-informed prevention strategy/ies.

Venous thromboembolic events after bariatric surgery: Protocol for a systematic review and meta-analysis

•

Venous Thromboembolic Events after Bariatric Surgery.

•

This protocol undertakes a systematic review and metanalysis of venous thromboembolic events after bariatric surgery.

•

Methodology, searches, eligibility, and data extraction for analysis are described.

•

Following the PRISMA guidelines, it describes the approach for pooled estimates.

•

Findings will have key clinical consequences for patient care.

Introduction

Considerably large numbers of bariatric surgery (BS) procedures are undertaken globally, and are projected to increase with the obesity epidemic. Venous thromboembolic events (VTE) comprise an important cause of postoperative morbidity and mortality after BS and an important issue with wide clinical and financial repercussions. Yet, a precise extent of the prevalence of VTE after BS for obesity and its mortality remains uncertain.

Methods and analysis

In order to respond to this knowledge gap, we will conduct a systematic review and meta-analysis of the prevalence of and mortality associated with VTE after BS. This protocol outlines the methodology that will be used and the search strategies and eligibility criteria that will be utilized to identify and select studies, as well as the method by which data from the selected studies will be extracted for analysis. PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), WHO International Clinical Trials Registry Platform, Cochrane Library, MEDLINE, Scopus, clinicaltrials.gov and Google scholar will be searched from 01 January 1990 through 10th April 2020, for original studies written in English that provided prevalence estimates of VTE after BS. Articles will also be searched for mortality estimates of VTE after BS. STROCSS (Strengthening the Reporting of Cohort Studies in Surgery) criteria will evaluate the methodological quality of the selected studies. The use of fixed effect or random effects model will be subject to the findings of the statistical tests for heterogeneity. Publication bias will be visually estimated by inspecting the funnel plots. Pooled estimates will be computed. Th current protocol conforms to the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines and has been submitted to the PROSPERO International Prospective Register of systematic reviews. No ethical clearance is required for this study. This systematic review and meta-analysis will be published in a peer-reviewed journal and presented at national and international conferences.

Association Between Surgeon Practice Knowledge and Venous Thromboembolism

BACKGROUND

The most common cause of mortality following bariatric surgery is venous thromboembolism. Our study aimed to (1) determine the practice patterns of venous thromboembolism (VTE) chemoprophylaxis among bariatric surgeons participating in a large statewide quality collaborative and (2) compare the results of surgeon self-reported chemoprophylaxis practices to actual practices from abstracted chart data.

METHODS

We administered a 13-question survey to 66 surgeons across a statewide collaborative aimed at revealing VTE practice patterns such as medication type, dosage, timing, duration, and level of trainee involvement (response rate 93%). We conducted on-site data audits to examine the charts of all patients that had developed VTE during the study period and 15 other randomly selected patient charts per site. We then evaluated both the ordered perioperative chemoprophylaxis and the actual administered chemoprophylaxis from nursing and electronic records.

RESULTS

There was 31% overall discordance between self-reported and abstracted chart data for pre-operative VTE dosing regimens. Among patients who had a VTE, 39% of administered chemoprophylaxis did not match surgeon responses. Conversely, among patients who did not have a VTE, only 29% were discordant (p = 0.03). In contrast, for post-operative VTE dosing, there was no significant difference in the rate of discordance in patients with and without a VTE (47% discordance vs 38%, p = 0.0552, respectively).

CONCLUSIONS

Greater discordance between surgeon self-reported and actual perioperative VTE chemoprophylaxis is associated with significantly increased risk of VTE. Further understanding of the system characteristics associated with these practices may yield insights into how best to improve appropriate VTE chemoprophylaxis.

Venous thromboembolism risk for the contemporary bariatric surgeon

BACKGROUND

Postoperative venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), are the leading causes of morbidity and mortality after bariatric surgery. Although several studies have examined VTE, few have examined risk factors separately for DVT and PE after contemporary bariatric surgery, including laparoscopic sleeve gastrectomy (LSG). Our objective was to define risk factors for DVT and PE independently for both LSG and laparoscopic Roux-en-Y gastric bypass (LRYGB) patients using the largest validated bariatric surgery database.

METHODS

The metabolic and bariatric surgery accreditation and quality improvement program (MBSAQIP) database was queried to identify patients who underwent LSG or LRYGB between January 2015 and December 2017. Perioperative data were compared using bivariate analysis. Risk of DVT and PE after LSG or LRYGB was determined using multivariable logistic regression analysis.

RESULTS

During the study period, 369,032 bariatric cases (72% LSG, 28% LRYGB) were performed. The incidence of DVT was similar between LSG and LRYGB (0.2% vs. 0.2%, p = 0.96), while the incidence of PE was decreased for LSG compared to LRYGB (0.1% vs. 0.2%, p < 0.001). Operative length was associated with increased risk of postoperative DVT (OR 1.1, CI 1.01-1.30, p = 0.04) and postoperative PE (OR 1.4, CI 1.16-1.64, p < 0.001) after surgery. The largest independent risk factors for DVT were history of DVT (OR 6.2, CI 4.44-8.45, p < 0.001) and transfusion (OR 4.2, CI 2.48-6.63, p < 0.001). The largest independent risk factors for PE were transfusion (OR 5.0, CI 2.69-8.36, p < 0.001) and history of DVT (OR 2.8, CI 1.67-4.58, p < 0.001). LSG was associated with a decreased risk of PE compared to LRYGB (OR 0.7 CI 0.55-0.91, p = 0.01).

CONCLUSIONS

Prolonged operative length is associated with a higher risk of DVT and PE after either LSG or LRYGB. Transfusion and history of DVT are the largest risk factors for developing DVT and PE. There is a decreased risk of PE after LSG compared to LRYGB.

Evaluating Time to In-Hospital Venous Thromboembolism in Obese Patients

BACKGROUND

Currently, no consensus approach exists for optimal venous thromboembolism (VTE) prophylaxis in obese (BMI ≥30 kg/m²) patients. Time to development of in-hospital VTE is not well studied.

OBJECTIVE

This study evaluates time to in-hospital VTE in obese patients.

METHODS

A single-center, retrospective study evaluated obese patients that developed an in-hospital VTE. Patients were categorized into 3 BMI groups: 30 to 34.9 (group 1), 35 to 39.9 (group 2), and ≥40 (group 3) kg/m². The primary end point compared time to VTE between the groups.

RESULTS

A total of 246 patients were included, and time to VTE was similar between the groups, 8 (group 1) versus 8 (group 2) versus 9 days (group 3); P = .38. Secondary outcomes showed time to VTE was shorter in acute care versus ICU patients (7.5 vs 10 days; P = .01), nonsurgical versus surgical patients (6 vs 9 days; P = .004), and no prophylaxis versus mechanical plus pharmacologic prophylaxis (4.5 vs 9 days; P < .001).

CONCLUSIONS

BMI category did not significantly impact time to in-hospital VTE. This study provides insight into the timing of in-hospital VTE in obese patients. The differences in prophylactic strategies highlight the importance of optimized prophylaxis.

Systemic thrombolysis for acute submassive pulmonary embolism after laparoscopic Roux-en-Y bypass: A case report

INTRODUCTION

Venous thromboembolism (VTE) in bariatric surgery is a low incidence disease; however, it is the first cause of morbimortality in this group of patients.

PRESENTATION OF THE CASE

We present the case of a female patient with morbid obesity who was readmitted due to an acute submassive bilateral pulmonary embolism (PE) nineteen days after a laparoscopic Roux-en-Y gastric bypass (RYGB). After diagnosis, anticoagulation was initiated, and decision to add mechanical and pharmacological thrombolysis was made with the patient been successfully treated, as shown by normalization of pulmonary hypertension.

DISCUSSION

VTE in bariatric surgery is rare but contributes to significant morbidity and mortality in patients undergoing bariatric surgery.

CONCLUSION

It is necessary to have a high index of suspicion to make a timely diagnosis and initiate an early treatment. In selected cases, adding mechanical and pharmacological thrombolysis could increase chance of reverse pulmonary hypertension.

Weight-adjusted tinzaparin for the prevention of venous thromboembolism after bariatric surgery

Essentials The optimal dose and duration of thromboprophylaxis after bariatric surgery are unclear. We evaluated the safety of weight-adjusted tinzaparin prophylaxis in 1212 patients. In-hospital rates of venous thromboembolism and major bleeding were 0.2% and 1.8% respectively. In a sub-set of patients, trough anti-Xa levels did not show excessive anticoagulant activity.

SUMMARY

Background Patients undergoing bariatric surgery are at moderate to high risk of venous thromboembolism (VTE). The optimal dose and duration of anticoagulant prophylaxis is uncertain. Objective To evaluate the safety of extended-duration weight-adjusted tinzaparin after bariatric surgery. Patients/methods We conducted a single-center retrospective cohort study of consecutive patients undergoing bariatric surgery who received weight-adjusted tinzaparin 4500-14 000 IU daily (75 IU kg-1 rounded to the nearest prefilled syringe) for 10 days after surgery (7-9 days post-hospital discharge). Primary safety outcomes were the frequency of VTE and major bleeding within 30 days of surgery in patients receiving at least one dose of tinzaparin. Results A total of 1279 patients undergoing bariatric surgery between July 2009 and December 2012 were reviewed, of whom 1212 received weight-adjusted tinzaparin. Safety outcomes were collected for 819 patients at 30 days, and for 1212 patients in-hospital only. The median age was 45.0 years, median weight was 130.0 kg and 98.8% of patients underwent gastric bypass or sleeve gastrectomy. In patients completing 30 days of follow-up, VTE occurred in 4/819 (0.5%) and major bleeding occurred in 13/819 patients (1.6%). In-hospital rates of VTE and major bleeding during surgical admission were 3/1212 (0.2%) and 22/1212 (1.8%), respectively. Conclusions Extended thromboprophylaxis with weight-adjusted tinzaparin appears to be a safe strategy after bariatric surgery, with low rates of postoperative VTE and major bleeding.

The Effect of Obesity on Anti-Xa Concentrations in Bariatric Patients

BACKGROUND

Morbidly obese patients are at increased risk to develop venous thromboembolism (VTE), especially after bariatric surgery. Adequate postoperative thrombosis prophylaxis is of utmost importance. It is assumed that morbidly obese patients need higher doses of low molecular weight heparin (LMWH) compared to normal-weight patients; however, current guidelines based on relative efficacy in obese populations are lacking.

OBJECTIVES

First, we will evaluate the relationship between body weight descriptors and anti-Xa activity prospectively. Second, we will determine the dose-linearity of LMWH in morbidly obese patients.

SETTING

This study was performed in a general hospital specialized in bariatric surgery.

METHODS

Patients were scheduled for a Roux-en-Y gastric bypass with a total bodyweight (TBW) of ≥ 140 kg. Patients (n = 50, 64% female) received a daily postoperative dose of 5700 IU of nadroparin for 4 weeks. Anti-Xa activity was determined 4 h after the last nadroparin administration. To determine the dose linearity, anti-Xa was determined following a preoperative dose of 2850 IU nadroparin in another 50 patients (52%).

RESULTS

TBW of the complete group was 148.5 ± 12.6 kg. Mean anti-Xa activity following 5700 IU nadroparin was 0.19 ± 0.07 IU/mL. Of all patients, 32% had anti-Xa levels below the prophylactic range. Anti-Xa activity inversely correlated with TBW (correlation coefficient - 0.410) and lean body weight (LBW; correlation coefficient - 0.447); 67% of patients with a LBW ≥ 80 kg had insufficient anti-Xa activity concentrations. No VTE events occurred.

CONCLUSIONS

In morbidly obese patients, a postoperative dose of 5700 IU of nadroparin resulted in subprophylactic exposure in a significant proportion of patients. Especially in patients with LBW ≥ 80 kg, a higher dose may potentially be required to reach adequate prophylactic anti-Xa levels.

Profilaxia da trombose venosa profunda em cirurgia bariátrica: estudo comparativo com doses diferentes de heparina de baixo peso molecular

Contexto

A cirurgia bariátrica é considerada a melhor opção para o tratamento da obesidade, cujos pacientes são considerados de alto risco para fenômenos tromboembólicos.

Objetivos

Comparar o uso de doses diferentes de heparina de baixo peso molecular (HBPM) na profilaxia da trombose venosa profunda (TVP) em pacientes candidatos à cirurgia bariátrica em relação ao risco de TVP, alteração na dosagem do fator anti-Xa e sangramento pré ou pós-operatório.

Métodos

Estudo comparativo transversal em pacientes submetidos à cirurgia bariátrica distribuídos em dois grupos, que receberam doses de HBPM de 40 mg (grupo controle, GC) e 80 mg (grupo de estudo, GE). Foram avaliados por ultrassonografia vascular e dosagem de KPTT, TAP, plaquetas e fator anti-Xa.

Resultados

Foram avaliados 60 pacientes, sendo 34 no GC e 26 no GE. Foi observada diferença significativa somente no peso (p = 0,003) e índice de massa corporal (p = 0,018) no GE em relação ao GC. Não houve diferença na dosagem de KPTT, TAP, plaquetas e fator anti-Xa entre os grupos. Não foram detectados TVP ou sangramentos significativos em ambos os grupos.

Conclusões

Não houve diferença estatisticamente significativa na utilização de doses maiores de HBPM na profilaxia da TVP em pacientes candidatos à cirurgia bariátrica em relação ao risco de TVP, dosagem do fator anti-Xa e sangramento pré ou pós-operatório.

Comprehensive Care for Bariatric Surgery Patients

Obesity is a worldwide epidemic, and those suffering from obesity have increased morbidity and mortality rates. There are various causes of obesity and many treatment options for patients suffering from obesity, including nonsurgical treatments. However, bariatric surgery is often the best choice for optimal weight loss and the attenuation of comorbidities. Currently, laparoscopic sleeve gastrectomy is the most common type of bariatric surgery in the United States due to its technical simplicity, feasibility, and overall positive outcomes. This article discusses bariatric surgical criteria and selection, expected perioperative course, potential complications after surgery, and nursing implications for the care of bariatric patients. A case report is used to exemplify stages of surgical care and follow-up treatment for patients who undergo laparoscopic sleeve gastrectomy.

Pharmacokinetics and pharmacodynamics of single doses of rivaroxaban in obese patients prior to and after bariatric surgery

AIMS

Venous thromboembolism is an important cause of postoperative morbidity and mortality in bariatric surgery. Studies of direct oral anticoagulants (DOACs) are not available in this surgical field. The objective of this phase 1 clinical trial was to investigate pharmacokinetic and pharmacodynamic (PK/PD) parameters of rivaroxaban in bariatric patients.

METHODS

In this single-centre study, obese patients received single oral doses of rivaroxaban (10 mg) 1 day prior to and 3 days after bariatric surgery. PK and PD parameters were assessed at baseline and during 24 h after drug ingestion.

RESULTS

Six Roux-en-Y gastric bypass patients and six sleeve gastrectomy patients completed the study. Mean rivaroxaban area under plasma concentration-time curve, peak plasma concentration, time to peak plasma concentration and terminal half-life were 971.9 μg·h l^-1 (coefficient of variation: 10.6), 135.3 μg l^-1 (26.7), 1.5 h and 13.1 h (34.1) prior to and 1165.8 (21.9), 170.0 (15.9), 1.5 and 8.9 (44.6) postsurgery for SG patients and 933.7 μg·h l^-1 (22.3), 136.5 μg l^-1 (10.7), 1.5 h und 13.8 h (46.6) prior to and 1029.4 (7.4), 110.8 (31.8), 2.5 and 15 (60.0) postsurgery for Roux-en-Y gastric bypass patients, respectively. Prothrombin fragments (F1 + 2) decreased during the first 12 hours and increased thereafter in the pre- and the postbariatric setting. Thrombin-antithrombin complexes dropped within 1-3 h in the prebariatric setting and remained low after surgery until they increased at 24 h postdose. Rivaroxaban was well tolerated and no relevant safety issues were observed.

CONCLUSIONS

Bariatric surgery does not appear to alter PK of rivaroxaban in a clinically relevant way. Effective prophylactic postbariatric anticoagulation is supported by changes in PD.

Effect of adding intrathecal morphine to a multimodal analgesic regimen for postoperative pain management after laparoscopic bariatric surgery: a prospective, double-blind, randomized controlled trial

BACKGROUND

Pain control after bariatric surgery is a major challenge. Our objective was to study the efficacy and safety of intrathecal (IT) morphine 0.3 mg added to bupivacaine 0.5% for postoperative pain after laparoscopic bariatric surgery.

METHODS

After local ethics committee approval, 100 morbidly obese patients scheduled for laparoscopic bariatric surgery were enrolled in this study. Patients were randomly assigned into two groups: Group I received IT 0.3 mg morphine (0.3 mL) added to 1.2 mL of bupivacaine 0.5%; Group II received IT 0.3 mL saline added to 1.2 mL of bupivacaine 0.5%, immediately before induction of general anaesthesia. For both groups, 60 mg ketorolac and 1000 mg paracetamol were infused 30 minutes before the end of surgery. After wound closure, 20 mL bupivacaine 0.25% was infiltrated at wound edges.

RESULTS

Visual Analogue Scale (VAS) score was significantly lower in group I immediately, 30 minutes and 1 hour postoperatively. Time to first ambulation, return of intestinal sounds and hospital stay were shorter in group I than group II (p < 0.05); total morphine consumption was significantly lower in group I than group II (p < 0.05). Sedation score was significantly higher in group I immediately postoperatively, while at 30 minutes, 1, 2 and 6 hours postoperatively sedation scores were significantly higher in group II. Itching was significantly higher in group I.

CONCLUSION

The addition of IT morphine to a multimodal analgesic regimen after laparoscopic bariatric surgery was an effective and safe method that markedly reduced postoperative pain, systemic opioid consumption and length of hospital stay.

Development of a pharmacist-driven protocol for automatic medication dosage adjustments in obese patients

PURPOSE

A hospital protocol utilizing automatic dosage adjustments and pharmacist consultations to optimize the use of certain medications in obese patients is described.

SUMMARY

After conducting a literature search focused on medication dosing in obese patients, pharmacists at a large community hospital developed a list of commonly ordered medications appropriate for inclusion in a pharmacy-driven institutional protocol for automatic medication dosage adjustment in adult patients with obesity. Evidence-based recommendations on initial dosing of eight antimicrobials and two anticoagulant agents according to weight and renal function were formulated. Under the protocol, pharmacists receive electronic alerts regarding protocol-eligible patients during initial order verification and automatically adjust medication dosages as appropriate. For patients prescribed anticoagulants at specified dosage levels, clinical pharmacists consult with prescribers to help ensure safe and effective initial and ongoing therapy. Multidisciplinary educational initiatives were conducted prior to protocol implementation. During two designated three-week postimplementation data collection periods, pharmacists received a total of 372 protocol-eligible medication orders. Pharmacists adjusted a total of 149 dosages and verified an additional 183 dosages consistent with the protocol as originally ordered. Clinical pharmacy consults were completed for 10-15% of patients, with laboratory monitoring ordered in 25-30% of those cases (all patients were found to have appropriate test values). There have been no documented adverse drug reactions in patients whose medication dosages were adjusted per protocol.

CONCLUSION

Pharmacists implemented weight- and renal function-based dosage adjustments for obese patients in 40% of evaluated protocol-eligible cases to achieve 89% compliance with the protocol. Heparin and cefazolin were the medications most likely to require obesity-related dosage adjustments.

Trends in bariatric surgery from 2008 to 2012

BACKGROUND

Obesity is a global epidemic that has been increasing in prevalence. The only treatment method for durable weight loss is bariatric surgery. The aim of this study was to observe trends in usage and outcomes of bariatric operations used in the United States from 2008 to 2012.

METHODS

Analysis was performed on bariatric surgery admissions from 2008 to 2012 based off of the Nationwide Inpatient Sample database. Data were selected from using International Classification of Disease, 9th Revision codes correlating to bariatric procedures for the purpose of obesity. Annual estimates and trends were reviewed for patient demographics, procedure type, patient outcomes, and length of stay (LOS).

RESULTS

A total of 598,756 bariatric procedures were examined. Laparoscopic gastric bypass was the most commonly used surgical method in 2008 (58.2%). A decreasing trend in its use, and the use of laparoscopic gastric banding (LGB), was equipoised with increasing use of laparoscopic sleeve gastrectomy (LSG). Use of LSG accounted for 8.2% of procedures in 2011 and 39.6% in 2012. LGB and LSG had the lowest rates of complications, in-hospital morbidity and mortality, and the shortest LOS whereas open bypass and duodenal switch had the highest rates of complications, in-hospital morbidity and mortality, and longest LOSs. Overall rates of venous thromboembolism increased from .08% in 2008 to .215% in 2012. Respiratory complications decreased from 6.1% to 3.9%. There were no observed trends in rates of renal complications, visceral injury, bleeding, and infections. In-hospital morbidity decreased, whereas mortality rates were stable at .1%.

CONCLUSIONS

The utilization of bariatric procedures has reached a plateau in the United States. Changes in the composition of procedural types suggest that LSG has become a popular alternative to gastric bypass and LGB.

The Anti-Factor Xa Range For Low Molecular Weight Heparin Thromboprophylaxis

Low molecular weight heparins (LMWHs) are now the mainstay option in the prevention and treatment of venous thromboembolism. In some patients receiving therapeutic doses of LMWH, activity can be measured by quantifying the presence of Anti-factor Xa (AFXa) for dose adjustment. However, currently there are no guidelines for LMWH monitoring in patients on thromboprophylactic, doses, despite certain patient populations may be at risk of suboptimal dosing. This review found that while the AFXa ranges for therapeutic levels of LMWHs are relatively well defined in the literature, prophylactic ranges are much less clear, thus making it difficult to interpret current research data. From the studies published to date, we concluded that a reasonable AFXa target range for LMWH deep venous thromboses prophylaxis might be 0.2-0.5 IU/mL.

Critical Care Management of Bariatric Surgery Complications

Obesity remains a major medical disease that often requires surgical intervention in morbidly obese patients. Surgical procedures have evolved and are performed routinely in most major medical centers. Outcomes are often dependent on patient characteristics, type of procedure, and preoperative planning. Risk stratification often depends on screening and optimizing known comorbidities often encountered in this patient population. A thorough understanding of the physiologic changes seen in obese patient and the commonly performed operations will allow the physician to perform optimal treatment strategies.

Measuring anti-factor xa activity to monitor low-molecular-weight heparin in obesity: a critical review

BACKGROUND

The choice of whether to monitor anti-factor Xa (anti-Xa) activity in patients who are obese and who are receiving low-molecular-weight heparin (LMWH) therapy is controversial. To the authors' knowledge, no systematic review of monitoring of anti-Xa activity in such patients has been published to date.

OBJECTIVE

To systematically ascertain the utility of monitoring anti-Xa concentrations for LMWH therapy in obese patients.

DATA SOURCES

MEDLINE (1946 to September 2014), the Cochrane Database of Systematic Reviews, Embase (1974 to September 2014), PubMed (1947 to September 2014), International Pharmaceutical Abstracts (1970 to September 2014), and Scopus were searched using the terms obesity, morbid obesity, thrombosis, venous thrombosis, embolism, venous thromboembolism, pulmonary embolism, low-molecular weight heparin, enoxaparin, dalteparin, tinzaparin, anti-factor Xa, anti-factor Xa monitoring, anti-factor Xa activity, and anti-factor Xa assay. The reference lists of retrieved articles were also reviewed.

STUDY SELECTION AND DATA EXTRACTION

English-language studies describing obese patients treated with LMWH or reporting anti-Xa activity were reviewed using a 9-step decision-making algorithm to determine whether monitoring of LMWH therapy by means of anti-Xa activity in obesity is warranted. Studies published in abstract form were excluded.

DATA SYNTHESIS

The analysis showed that anti-Xa concentrations are not strongly associated with thrombosis or hemorrhage. In clinical studies of LMWH for thromboprophylaxis in bariatric surgery, orthopedic surgery, general surgery, and medical patients, and for treatment of venous thrombo embolism and acute coronary syndrome, anti-Xa activity can be predicted from dose of LMWH and total body weight; no difference in clinical outcome was found between obese and non-obese participants.

CONCLUSIONS

Routinely determining anti-Xa concentrations in obese patients to monitor the clinical effectiveness of LMWH is not warranted on the basis of the current evidence. Circumstances where measurement of anti-Xa concentration may help in clinical decision-making in either obese or non-obese patients would be cases where elimination of LMWH is impaired or there is an unexpected clinical response, as well as to confirm compliance with therapy or to identify deviation from predicted pharmacokinetics.

Appropriate enoxaparin dose for venous thromboembolism prophylaxis in patients with extreme obesity

OBJECTIVE

To evaluate the appropriate dose of enoxaparin for venous thromboembolism (VTE) prophylaxis in patients with extreme obesity.

METHODS

A literature search was performed using MEDLINE (1950-April 2013) to analyze all English-language articles that evaluated incidence of VTE and/or anti-Xa levels with enoxaparin for thromboprophylaxis in patients with extreme obesity.

RESULTS

Eight studies were included in the analysis. Six of the studies were done in patients undergoing bariatric surgery. Mean body mass index ranged from 44.9 to 63.4 kg/m(2) within studies. Studies done with bariatric surgery patients utilized doses of enoxaparin that ranged from the standard dose of 30 mg subcutaneous (SQ) every 12 hours to 60 mg SQ every 12 hours. Other studies evaluated doses ranging from 40 mg SQ every 24 hours to 0.5 mg/kg/day. Only 3 studies evaluated the incidence of VTE as the primary endpoint; the other studies evaluated anti-Xa levels. The studies showed that appropriate anti-Xa levels were achieved more often with higher than standard doses of enoxaparin. One study showed that enoxaparin 40 mg SQ every 12 hours decreased the incidence of VTE in patients undergoing bariatric surgery compared to standard doses. Overall risk of bleeding was similar between study groups.

CONCLUSIONS

Higher than standard doses of enoxaparin may be needed for patients with extreme obesity. Patients undergoing bariatric surgery may benefit from enoxaparin 40 mg SQ every 12 hours. Additional large randomized, controlled trials are needed to determine the efficacy and safety of higher than standard doses of enoxaparin for VTE prophylaxis in patients with extreme obesity.

Rapid opiate detoxification and antagonist induction under general anaesthesia or intravenous sedation is humane, sometimes essential and should always be an option. Three illustrative case reports involving diabetes and epilepsy and a review of the literature

When abstinence is an appropriate goal, controlled studies and systematic reviews confirm that rapid, antagonist-precipitated opiate withdrawal procedures are the most effective and cost effective methods of initiating abstinence, and naltrexone (NTX) maintenance. While 'rapid' withdrawal, better conceptualised as Rapid Antagonist Induction (RAI), can often be humanely achieved with modest sedation levels, we present three case histories to support our argument that for some patients, general anaesthesia (GA), or techniques of intravenous sedation (IVS) that approach GA, are essential for safety and success. This includes patients with intercurrent disease (e.g. epilepsy or insulin-dependent diabetes) but also those with severe withdrawal phobia after previous distressing experiences. We discuss the history of the procedure. The dangers of RAI under GA or IVS in experienced hands have been exaggerated and the appropriate expertise should be more easily available. Patients and clinicians readily accept risks of major surgery for the excessive intake of food that causes most obesity. Similar risk-acceptance exists in cosmetic surgery and obstetrics. The increasing use and effectiveness of long-acting implants or depot-injections of NTX for relapse-prevention have largely solved compliance problems that undermined the potential of oral NTX. Their ability to prevent opiate overdose in abstinent, non-tolerant patients also strengthens arguments both for offering RAI as a therapeutic option and for reducing psychological, professional and practical barriers to using it.

Adding chemoprophylaxis to sequential compression might not reduce risk of venous thromboembolism in bariatric surgery patients

BACKGROUND

Anticoagulation, the use of sequential compression devices on the lower extremities perioperatively, and early ambulation are thought to reduce the incidence of venous thromboembolism (VTE) postoperatively and are recommended to reduce VTE risk. However, the evidence on which this recommendation has been based is not particularly strong. We have demonstrated that even a large, multicenter cohort with carefully collected prospective data is inadequate to provide sufficient evidence to support, or refute, this recommendation.

METHODS

Longitudinal Assessment of Bariatric Surgery participants from 10 centers in the United States who underwent their first bariatric surgery between March 2005 and December 2007 constituted the study group. We examined the ability to address the question of whether anticoagulation therapy, in addition to sequential compression, reduces the 30-day incidence of VTE or death sufficiently to recommend the use of prophylactic anticoagulation, a therapy that is not without risk.

RESULTS

Of 4416 patients, 396 (9.0%) received sequential compression alone, and 4020 also received anticoagulation therapy. The incidence of VTE within 30 days of surgery was low (.25% among those receiving sequential compression alone and .47% when anticoagulation therapy was added), and the 30-day incidence of death was also low (.25% versus .34%, respectively, P = .76, for sequential compression alone versus sequential compression plus anticoagulation therapy). Estimates of the number of cases required to address the question of whether a difference exists in the outcome related to VTE chemoprophylaxis or whether the outcome rates are equivalent have ranged from 13,680 to ≥ 35,760 patients, depending on whether superiority or equivalence was being analyzed.

CONCLUSION

Sufficient evidence from a clinical trial study to determine whether prophylactic anticoagulation added to compression devices further prevents VTE is not available, and such a trial is likely to be impractical. The data presented are insufficient to make a final recommendation concerning prophylactic treatment to prevent VTE in the 30 days after bariatric surgery.

Impact of screening versus symptomatic measurement of deep vein thrombosis in a national quality improvement registry

BACKGROUND

Deep vein thrombosis (DVT) is a quality measure recorded by initiatives such as the National Surgical Quality Improvement Program (NSQIP). However, because surveillance-detected DVT rates may be higher than symptomatic DVT rates, we examined how differences in the method of DVT detection may affect the use of this quality measure.

METHODS

Using the NSQIP database (2007-2009), we compared DVT rates of vascular (amputation, open aortic procedures, and lower extremity bypass) and nonvascular (prostatectomy, gastric bypass [GBP], and hip arthroplasty) operations. Using a predefined literature search strategy, we compared the incidence of DVT in NSQIP to the incidence of DVT reported in published literature, diagnosed by symptomatic status or by surveillance studies.

RESULTS

Within NSQIP, the overall incidence of postoperative DVT was 0.7%. This varied from 0.3% after GBP to 1.8% after open aortic surgery. Across all procedures except amputation, the incidence of DVT in NSQIP was similar to the incidence of DVT reported in our literature survey of "symptomatic" DVTs. The relative rate (RR) of literature-derived symptomatic DVTs to NSQIP ranged from 0.7 for aortic cases (95% confidence interval [CI], 0.3-1.7) to 1.4 (95% CI, .7-3.1) for GBP. Overall, surveillance studies had 11.6 higher RR of DVT compared to NSQIP (95% CI, 10.5-13), ranging from 2.6 for GBP (95% CI, 1.4-5) to 14 .5 for hip arthroplasty (95% CI, 10.5-20).

CONCLUSIONS

The incidence of DVT reported in NSQIP is similar to the reported incidence of symptomatic DVT for many high-risk procedures but is much lower than rates of DVT reported in surveillance studies. Clear delineation of symptomatic vs surveillance detection of DVT would improve the usefulness of this measurement in quality improvement registries.

Aortic thrombus after bariatric surgery

Laparoscopic gastric bypass is becoming a frequently performed bariatric operation for patients with obesity. However, bariatric surgery has inherent risks and complications, which are further potentiated by the high risk nature of bariatric patients. These complications can be either site specific i.e. anastomotic leaks, or systemic i.e. venous thromboembolism, however they can intimately related. We present the case of one patient undergoing routine gastric bypass complicated postoperatively by recurrent intra-abdominal collections and sepsis, and aortic thrombosis with distal embolisation.

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.

Medical management of postsurgical complications: the bariatric surgeon's perspective

Bariatric surgery remains the only effective method to initiate and sustain massive weight loss in morbidly obese patients. Along with the advent of minimal access surgery, its popularity has not only resulted in an exponential increase in number of cases but also a subsequent increase in number of complications. Although most postsurgical bariatric complications are managed surgically, it is imperative that all physicians be aware of the unique potential complications to effectively communicate and optimize the medical management in this emergent set of patients.

Prevention of venous thromboembolism in obesity

Venous thromboembolism (VTE) is a significant cause of morbidity and mortality in hospitalized patients. Where appropriate, evidence-based methods of prophylaxis are implemented and the burden of VTE can be reduced substantially. Obesity, including morbid obesity, is associated with a high risk of VTE and, unfortunately, fixed doses of US FDA-approved anticoagulant regimens, including unfractionated heparins, low-molecular-weight heparins and factor Xa inhibitors, may not provide optimal VTE prophylaxis in these patients. Although the data are still limited, a rapidly growing body of literature and cumulative evidence suggests that anticoagulant dose adjustments in morbidly obese patients may optimize pharmacodynamic activity and reduce VTE risk. With the prevalence of morbid obesity continuing to rise, more high-quality clinical data are needed to better understand the pathobiology of VTE in obesity and provide effective, yet safe, prevention strategies.

Anticoagulation: Low-Molecular-Weight Heparins in Renal Impairment and Obesity: Available Evidence and Clinical Practice Recommendations Across Medical and Surgical Settings

Objective

To develop practical recommendations for the use of low-molecular-weight heparins (LMWHs) as prophylaxis and treatment of venous thromboembolism and acute coronary syndromes in patients with impaired renal function or obesity.

Data Sources

Multiple MEDLINE searches were performed (November 2008) to identify studies for inclusion, using a comprehensive list of search terms including, but not limited to, LMWH, enoxaparin, dalteparin, tinzaparin, obesity, weight, renal, kidney, elderly, monitoring, and anti-Xa.

Study Selection And Data Extraction

Only articles published in English that were relevant for this review were included.

Data Synthesis

In the majority of patients, standardized prophylaxis or treatment doses of LMWHs can be used without the need for monitoring and adjusting regimens. For patients with severe renal impairment (estimated creatinine clearance [CrCl] <30 mL/min), doses of some LMWHs should be adjusted or unfractionated heparin should be used instead. CrCl should be estimated using the Cockcroft-Gault method. Differences are noted in the degree of accumulation of various LMWHs in patients with moderate-to-severe renal impairment, and thus, the degree of dose adjustment may differ among the various LMWHs. Increasing the prophylactic doses of LMWH may be appropriate in morbidly obese patients (body mass index ≥40 kg/m2). The use of total body weight is appropriate for therapeutic doses of LMWH in obese patients. Laboratory monitoring of the anticoagulation effect of LMWHs is generally not necessary, but should be considered in patients with morbid obesity (weight >190 kg), those with severe renal impairment, and those with moderate renal impairment with prolonged (>10 days) LMWH use. When anti-Xa activity is monitored, it should be determined using a chromogenic method and a calibration curve based on the LMWH used.

Conclusions

Additional data are needed for specific dose guiding in obese and renally impaired patients, who are often excluded from larger clinical trials. Practice recommendations are made based on available evidence and authors' clinical opinions.