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Gut microbiome composition and microbial metabolomics changes after bariatric surgery

The authors from University Hospital in US and Spain studied the effect of gastric bypass and sleeve gastrectomy on the gut microbiome composition and bacterial pathways in 26 individuals with several obesity ± type 2 diabetes. Their relation to metabolic parameters before surgery and at 3, 6 and 12 months after bariatric surgery was studied. Microbial diversity and composition by 16 rRNA sequencing, putative bacterial pathways and targeted circulating metabolites were investigated. They found that there was an increase in alpha diversity and significant altered beta diversity, microbiota composition and function. This was seen up to 6 months postoperatively and returned to pre-surgery level by 12 months. Out of 15 bacterial pathways, 12 which had enriched after surgery also regressed back to pre-surgery level at 12 months. There were no differences between study sites, surgery types, or diabetes status in terms of microbial diversity and composition at baseline and after surgery. There were decreased circulating biomarkers of inflammation, increased bile acid and products of choline metabolism and other bacterial pathways. They concluded that microbiome partially mediated improvement of metabolism during the first year after bariatric surgery.

Shen, Nan, Assumpta Caixàs, Michael Ahlers, Kapila Patel, Zhan Gao, Roxanne Dutia, Martin J. Blaser, Jose C. Clemente, and Blandine Laferrère. "Longitudinal changes of microbiome composition and microbial metabolomics after surgical weight loss in individuals with obesity." Surgery for Obesity and Related Diseases (2019).

Effects of Roux-en-Y Gastric bypass on Barrett’s esophagus.

Gastroesophageal reflux disease (GERD) and Barrett’s esophagus (BE) are predisposed by obesity. It is well established that Roux-en-Y gastric bypass (RYGB) leads to weight loss and improvement of GERD in obese patients. The authors performed systematic review and meta-analysis to see the effect of RYGB on BE. On their systematic review of studies evaluating the effect of RYGB on BE with preoperative and postoperative endoscopy and biopsy, they found 8 studies with 10,779 patients to be included in the review. There was report of 117 patients with BE with follow up data of greater than 1 year. They observed significant regression of BE after RYGB. There was significant regression of both, short-segment BE and long segment BE (P <0.001). There was also significant improvement in the GERD symptoms in patients with BE. They concluded that RYGB was strongly associated with regression of BE compared to progression.

Adil, Md Tanveer, Omer Al-taan, Farhan Rashid, Aruna Munasinghe, Vigyan Jain, Douglas Whitelaw, Periyathambi Jambulingam, and Kamal Mahawar. "A Systematic Review and Meta-Analysis of the Effect of Roux-en-Y Gastric Bypass on Barrett’s Esophagus." Obesity surgery (2019): 1-10.

Failed adjustable Gastric band: Is conversion to sleeve gastrectomy or roux-en Y gastric bypass better?

Laparoscopic adjustable gastric band (LAGB) was one of the most common bariatric procedures. However, insufficient weight loss and band related problems has led to many patients needing revisional surgery. This meta-analysis is an attempt to establish whether conversion to Sleeve gastrectomy (SG) or Roux-en Y gastric bypass (RYGB) gives better clinical outcomes. Following the PRISMA guidelines, 586 articles were identified and from them 16 articles were included in this review. Reviewing 2141 SG and 2990 RYGB patients showed that percent excess weight loss (%EWL) at 1 year and 2 years was better in patients with RYGB compared to SG. There was no statistically significant difference in %EWL at 3 and 6 months or at 3 years. Patients who were converted to RYGB had longer operative time, higher rate of post-operative complications, readmissions and interventions compared to SG patients. The authors suggested that the overall status of patients and their comorbidities should be considered when selecting their revisional surgery.

Wu, Chang, Fu-gang Wang, Wen-Mao Yan, Ming Yan, and Mao-min Song. "Clinical Outcomes of Sleeve Gastrectomy Versus Roux-En-Y Gastric Bypass After Failed Adjustable Gastric Banding." Obesity surgery (2019): 1-12.

Prospective non-randomized study comparing GERD related physiologic changes after Sleeve gastrectomy and Roux-en Y gastric bypass

The reported incidence of gastroesophageal reflux disease (GERD) after sleeve gastrectomy (SG) is reported as high as 35% in literature. Objective evidence to prove that Roux-en y gastric bypass (RYGB) is better in patients with obesity with GERD is scarce. The authors studied non-GERD patients preoperatively and 6 months postoperatively after LSG and RYGB for incidence of GERD. Patients symptom index, 24-hour pH study, impedance and manometry to determine the physiologic changes related to GERD were looked at. Thirty SG and 16 RYGB patients were included in the study. The authors found that the mean DeMeester score increased significantly from 10.9 to 40.2 after SG postoperatively. Whereas the DeMeester score non-significantly increased from 9.5 preoperatively to 12.2 post-operatively after RYGB. The incidence of GERD after SG was as high as 66.6%. Interestingly they noted a significant increase in the non-acid reflux after both SG and RYGB. Based on their results, the authors concluded that SG should be contraindicated in patients with GERD.

Raj, P. Praveen, Siddhartha Bhattacharya, Shivanshu Misra, S. Saravana Kumar, Mohd Juned Khan, Sridhar Chinnaswami Gunasekaran, and C. Palanivelu. "Gastroesophageal reflux–related physiologic changes after sleeve gastrectomy and Roux-en-Y gastric bypass: a prospective comparative study." Surgery for Obesity and Related Diseases (2019).

Mortality following bariatric surgery in smokers and non-smokers

The authors conducted this retrospective cohort study in a large Israeli integrated health care organization to determine if the association of mortality and bariatric surgery is different in smokers and non-smokers. A total of 7747 adult patients who had bariatric surgery (gastric banding, Roux-en Y gastric bypass, Sleeve gastrectomy) in a period of 10 years from 2005 were matched for age, sex, diabetes and BMI with non-surgical patients. There was adjustment for key potential confounders. Total of 30,742 patients with a median follow up of 4.3 years were included in the study. They found that there was statistically significant higher mortality associated with not having bariatric surgery in both smokers and non-smokers. The overall mortality rate was 2.6% in smokers compared to 1.7% in non-smokers. However, the mortality hazard ratio comparing matched non-surgical patients to surgical patients was not significantly different between smokers and non-smokers. They concluded that bariatric surgery was associated with significantly lower mortality in both smokers and non-smokers.

Rasmussen-Torvik, Laura J., Orna Reges, Philip Greenland, Dror Dicker, Morton Leibowitz, Adi Berliner Senderey, Moshe Hoshen, and Ran D. Balicer. "All-Cause Mortality Following Bariatric Surgery in Smokers and Non-smokers." Obesity surgery (2019): 1-6.

Conversion to one anastomosis gastric bypass (OAGB) from adjustable gastric band and sleeve gastrectomy

Laparoscopic adjustable gastric banding (LAGB) and laparoscopic sleeve gastrectomy (LSG) are two of the commonly performed bariatric procedures. Some patients require revisional bariatric surgery due to weight regain or late complications. One anastomosis gastric bypass (OAGB) is a promising bariatric procedure for such scenarios. Ten centres from Italy contributed to this retrospective study. A total of 300 patients were included in this study and their BMI, %EWL, reasons for revision, major complications and remission from comorbidities were compared. 196 patients had conversion from LAGB to OAGB and 104 were converted from SG to OAGB. Mean follow up was 20.8 months and 8.6% patients had major complications. BMI was 45.1 ± 7 kg/m2 at the time of primary operation and 41.8 ± 6.3 kg/m2 at OAGB. Mean excess BMI loss was 13.2 ± 28.2 at conversion and 73.4 ± 27.5 after OAGB. Remission rates for comorbidities like hypertension, diabetes, GERD and dyslipidemia were 40%, 62.5%, 58.7% and 52% respectively. The authors concluded that OAGB is safe and effective as a revisional procedure after failed restrictive procedures like LAGB and SG.

Musella, Mario, Vincenzo Bruni, Francesco Greco, Marco Raffaelli, Marcello Lucchese, Antonio Susa, Maurizio De Luca et al. "Conversion from Laparoscopic Adjustable Gastric Banding (LAGB) and Laparoscopic Sleeve Gastrectomy (LSG) to Mini/One Anastomosis Gastric Bypass (MGB/OAGB): preliminary data from a multicenter retrospective study." Surgery for Obesity and Related Diseases (2019).

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