Journal Review in Bariatric Surgery: Are Less Anastomoses Better?

Bariatric surgery is an evolving field with new procedures, or variations of old ones, being developed to meet the needs of patients with obesity. The single anastomosis duodenoileal bypass (SADI) and one anastomosis gastric bypass (OAGB) are two such procedures which have recently entered the mainstream conversation. In this episode we will give a brief overview of the SADI and OAGB, go over some short and long term studies evaluating safety and efficacy, and discuss current sentiments about these options and how they may fit into bariatric practice.

Show Hosts:
Matthew Martin, MD
Adrian Dan, MD
Crystal Johnson-Mann, MD
Paul Wisniowski, MD

Article #1: Chao 2024 - Outcomes of SADI and OAGB Compared to RYGB from the Metabolic and Bariatric Surgery Quality Improvement Program: The North American Experience

Roux-en-Y gastric bypass (RYGB) and duodenal switch are well described procedure for weight loss; however, associated postoperative complications have led to the development of simpler techniques
- Single anastomosis duodenoileal bypass (SADI) - modification of the duodenal switch where by a loop of ileum of the bilopancreatic limb approximately 200-300cm from the ileal cecal valve is anastomosed to the distal duodenal cuff of a tubularized stomach
- One anastomosis gastric bypass (OAGB) – modification of the RYGB where a loop of jejunum of the bilopancreatic limb approximately 150-200cm from the ligament of treitz is anastomosed to the distal end of a gastric pouch.
There is increasing interest in these procedures given the perceived reduced risk reduction associated with one fewer anastomosis
Currently, there is insufficient data on the safety of these procedures compared to the established RYGB.
The article utilizes the MBSAQIP database to evaluate each procedure against the RYGB
- Matched groups: SADI vs RYGB and OAGB vs RYGB
- Matched against age, sex, BMI, operative time, and ASA classification
- 30-day outcomes included complications and health care utilization
- Results were analyzed with univariate comparative analysis, and significant outcomes were examined with logistic regression
  - SADI vs RYGB: SADI independently associated INCREASED odds with staple line leak, sepsis, organ space infection, and pneumonia.
  - OAGB vs RYGB: OAGB independently associated with REDUCED odds of SSI, transfusion requirement/GI bleed, ICU admission, bowel obstruction, and healthcare utilization (reoperation, readmissions, and reinterventions)
  - No significant differences in mortality
- Limitation: Article generally reviews technical complications of procedures. Unable to address significant bariatric outcomes such as weight loss and metabolic profile, as well as long term outcomes.
- https://pubmed.ncbi.nlm.nih.gov/38170422/

Article #2: Maud 2019 - Efficacy and safety of OAGB vs RYGB for obesity (YOMEGA trial): A multicentre, randomized, open label, non-inferiority trial

Limited long-term evidence on OAGB
- Mostly arising from retrospective analyses and one meta-analysis
- Two randomized clinical trials but with poor power and questionable methodology.
This is a randomized non-inferiority trial of in patients undergoing bariatric surgery
- Randomized into 2 groups: OAGB vs RYGB with 117 patients per group
- Patients were followed for 2 years with a loss to follow up of 21% in OAGB and 24% in RYGB cohorts
- The primary outcome was weight loss with a noninferiority threshold of 7% assuming 60% weight loss at 2 years. Secondary outcomes included complications and metabolic outcomes
- Groups were compared with Student’s T and Wilcoxon tests for quantitative data, and chi-squared and Fischer’s exact for qualitative endpoints.
- Cohorts were analyzed with the intention to treat, and missing data on the primary endpoint was imputed with prediction-based modeling.
Highlighted Outcomes
- Mean percent excess BMI loss of 87.9% in OAGB group compared to 85.8% in RYGB group demonstrating non-inferiority in terms of weight loss
- Increased number of serious adverse events (SAE) in the OAGB group, but no difference in the proportion of patients with at least 1 SAE
- OAGB demonstrated 70% complete or partial remission of diabetes compared to 44% in RYGB but underpowered to demonstrate significant difference.
- Equal rates of gastritis and esophagitis based on endoscopic biopsy results at 2 years.
- There were increased nutritional complications in the OAGB groups with 21% vs 0% in RYGB and high rates of diarrhea/anal fissures 14% vs 0%, respectively. This suggests a greater malabsorptive effect of OAGB.
- There was equal satisfaction in quality of life between RYGB and OAGB on two validated surveys with >80% satisfaction rates.
Limitations
- Data was imputed for the primary end point
- High rates of loss to follow up in both cohorts
- Use of “severe adverse events” instead of Clavien-Dindo classification
- Comparison of specific institutional/surgeon technique of OAGB vs RYGB
- https://pubmed.ncbi.nlm.nih.gov/30851879/

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