Publications (67) View all
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Article: Bariatric surgery and diabetes: access denied.
Diabetes Technology & Therapeutics 02/2013; 15 Suppl 1:S83-7. · 1.93 Impact Factor -
Article: What distinguishes adipose tissue of severely obese humans who are insulin sensitive and resistant?
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ABSTRACT: Despite a strong correlation between obesity and insulin resistance, 25% of severely obese (BMI >40) individuals are insulin sensitive. In this review, we will examine the factors in adipose tissue that distinguish the two groups, as well as reasons for believing the insulin-sensitive group will be less disease prone. Obesity has been linked to the metabolic syndrome with an increase in visceral (intra-abdominal) compared to subcutaneous fat. Recent studies in which adipose tissue of insulin-sensitive and insulin-resistant patients with severe obesity were compared indicate that the insulin-resistant group is also distinguished by increases in oxidative stress and decreases in AMP-activated protein kinase (AMPK) activity. In contrast, changes in the expression of genes for SIRT1, inflammatory cytokines, mitochondrial biogenesis and function, and the two α-isoforms of AMPK showed more depot variation. Studies of how these and other changes in adipose tissue respond to bariatric surgery are still in their infancy. Available data suggest that increases in oxidative stress, decreases in AMPK activity and SIRT1 gene expression, depot-specific changes in inflammatory, mitochondrial and other genes distinguish adipose tissue of insulin resistant from insulin-sensitive individuals with severe obesity.Current opinion in lipidology 02/2013; 24(1):49-56. · 6.13 Impact Factor -
Article: Diabetes: Have We Got It All Wrong?: Hyperinsulinism as the culprit: surgery provides the evidence.
Diabetes care 12/2012; 35(12):2438-42. · 8.09 Impact Factor -
Article: Can technical factors explain the volume-outcome relationship in gastric bypass surgery?
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ABSTRACT: BACKGROUND: The existence of a relationship between surgeon volume and patient outcome has been reported for different complex surgical operations. This relationship has also been confirmed for patients undergoing Roux-en-Y gastric bypass (RYGB) in the Longitudinal Assessment of Bariatric Surgery (LABS) study. Despite multiple studies demonstrating volume-outcome relationships, fewer studies investigate the causes of this relationship. OBJECTIVE: The purpose of the present study is to understand possible explanations for the volume-outcome relationship in LABS. METHODS: LABS includes a 10-center, prospective study examining 30-day outcomes after bariatric surgery. The relationship between surgeon annual RYGB volume and incidence of a composite endpoint (CE) has been published previously. Technical aspects of RYGB surgery were compared between high and low volume surgeons. The previously published model was adjusted for select technical factors. RESULTS: High-volume surgeons (>100 RYGBs/yr) were more likely to perform a linear stapled gastrojejunostomy, use fibrin sealant, and place a drain at the gastrojejunostomy compared with low-volume surgeons (<25 RYGBs/yr), and less likely to perform an intraoperative leak test. After adjusting for the newly identified technical factors, the relative risk of CE was .93 per 10 RYGB/yr increase in volume, compared with .90 for clinical risk adjustment alone. CONCLUSION: High-volume surgeons exhibited certain differences in technique compared with low-volume surgeons. After adjusting for these differences, the strength of the volume-outcome relationship previously found was reduced only slightly, suggesting that other factors are also involved.Surgery for Obesity and Related Diseases 10/2012; · 3.93 Impact Factor -
Article: Adding chemoprophylaxis to sequential compression might not reduce risk of venous thromboembolism in bariatric surgery patients.
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ABSTRACT: 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.Surgery for Obesity and Related Diseases 07/2012; · 3.93 Impact Factor
