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IFSO Consensus Conference on OAGB-MGB

IFSO International Consensus Conference on OAGB-MGB (part 2)

The IFSO International Consensus Conference on One Anastomosis Gastric Bypass (OAGB-MGB), sponsored by Ethicon, took place on July 18-19 2019, at the Johnson and Johnson Institute, in Hamburg, Germany.

The IFSO International Consensus Conference on One Anastomosis Gastric Bypass (OAGB-MGB), sponsored by Ethicon, took place on July 18-19 2019, at the Johnson and Johnson Institute, in Hamburg, Germany. At the conference, the Expert Panel reviewed and discussed both the published findings for the procedures and the participants’ own data and subsequently voted to see whether there was consensus or no consensus on the specific topics.

A consensus statement discussing the findings will be submitted to a journal in the next few months. The topics under discussion at the conference were: The topics under discussion at the conference were: 1) Fundamentals of OAGB-MGB 2) Indications and Selection of Patients 3) Technical Systematization 4) Complications/Controversies: Diagnosis, Treatment and Prevention 5) Revision, Use as Revisional Surgery and Follow Up. Below are summaries of second session - Indications and Selection of Patients.

Module II: Indications and Selection of Patients

OAGB-MGB: Selection of Patients

Dr Enrique Luque-de-Leon (Mexico) said that OAGB-MGB are hypo-absorptive partially restrictive (mixed) procedures that should be compared to RYGB. OAGB (with its higher hypo-absorptive profile) may even be compared with the more complex bilio-pancreatic (BP) diverting procedures. In spite that patient selection for OAGB-MGB is really no different from other bariatric procedures, and he has not found specific contraindications for OAGB-MGB, he considers it is especially suited for certain subgroups of patients.


Dr Luque-de-Leon outlined specific considerations that represent a special fit for OAGB-MGB including:

  • Age and BMI – there are excellent long-term outcomes for young adults ³ 13 years of age, and elderly patients are no longer a contraindication, provided they are in good functional status and fulfil criteria for bariatric surgery (of note, common channel must always be larger than the BP limb for elderly patients). Moreover, the procedure has excellent outcomes in super-obese patients; as the OAGB includes total small bowel (SB) counting and a higher hypo-absortive component (60% BP limb), the results are comparable to more complex BP diverting procedures in this group of difficult patients.
  • Metabolic comorbidities - patients with massive central (visceral) obesity and/or advanced metabolic syndrome are especially suited for OAGB-MGB due to its great metabolic effect. This important metabolic profile makes OAGB-MGB an excellent choice for patients with type II DM (different BMI), and has shown a high index of long-term remission or at least improvement (especially in those patients with advanced disease).
  • GERD and Hiatal Hernia - obese patients with GERD, with or without esophagitis (of any degree, including non-dysplastic Barrett’s oesophagus), and hiatal hernia (any type), are suitable candidates and well-served with OAGB-MGB, primarily due to the low pressure system it establishes.
  • Small Bowel Status - since small bowel is bypassed in OAGB-MGB it needs to be freely mobilised and this is especially true for OAGB where total SB is counted from ligament of Treitz to ileo-cecal valve. Adhesions in patients with previous abdominal operations can usually be lysed with patience and care. Only those with a “hostile, frozen” abdomen represent a contraindication for OAGB-MGB (and actually any type of mixed procedure). Some have considered primary “short-gut” (total SB < 350 cm) a contraindication for OAGB-MGB; however, if total SB length is measured systematically (as in OAGB) and bypassed proportionally, outcomes should be the same as those achieved in patients with longer total SB lengths.
  • Revisional Surgery after other Failed Procedures: OAGB-MGB has demonstrated to be a superb choice to revise patients after failed restrictive procedures such as gastric banding and sleeve gastrectomy (SG). Due to the current popularity of this latter worldwide, conversion of SG to OAGB-MGB may become the most common revisional operation in the next decade. Since it acts as an anti-reflux procedure, revision to OAGB-MGB offers a second option to treat GERD after SG or even single-anastomosis duodeno-ileal bypass. It is similar in efficacy to RYGB, but more effective regarding substantial, long-term weight loss.
  • Special Requirements - obese chronic alcohol drinkers and smokers of tobacco must quit at least six months prior to surgery. Those with any other kind of drug addiction must have an eradication period of at least three years.

“Patient selection is key to optimising MGB/OAGB outcomes but is really not quite different from that of other procedures. Studies have demonstrated OAGB-MGB functions as an anti-reflux procedure improving GERD which is quite common in obese patients,” he concluded. “Moreover, OAGB-MGB has shown to be a great alternative in certain subgroups of patients (super-obese, super-super obese) including those with higher operative risks.”

Expected weight loss

Dr Hayssam Fawal (Lebanon) began by stating that there is growing evidence that MGBOAGB is a safe and effective procedure when compared to other bariatric procedures. The power of restriction together with malabsorption make it one of the most powerful procedures in terms of excess weight loss. Most of the excess weight in MGB OAGB happened during the first year with more than 70% EWL at one year. The literature shows that weight continue to drop slowly in the second and third year to reach a plateau and at eight and ten years EWL reaches 75% and 70%, respectively.

Hayssam Fawal

He said that most of the publications showed superiority of MGB OAGB when compared to sleeve. For example, Carbajo et al OAGB achieve superior mid- and long-term weight loss than RYGB and SG. There were no significant differences in weight loss between SG and RYGB at one, two and five years. A randomised trial by Shivakumar et al, revealed at 36 months follow up, there was no significant difference between LSG and MGB-OAGB in %EWL. MGB-OAGB patients with comorbidities have a better quality of life and BAROS score compared to LSG patients.

Comparative studies between MGB-OAGB and RYGB in terms of EWL showed non inferiority in one randomised trial and better EWL in MGB-OAGB in most of the studies at three, five and ten years of follow up. MGB-OAGB also proved its efficacy in the super obese when compared to sleeve and RYGB.

Dr Fawal presented his unpublished data comparing sleeve versus MGB OAGB in the super obese that showed similar excess weight loss in the first year and statistically significant difference in EWL at three years 57% versus 78%, respectively.

Similar results shown by Chetan Parmar (Sunderland group) when comparing RYGP to MGB-OAGB in the super obese with EWL 57% versus 70% respectively.

Fawal added that MGB-OAGB also showed a better EW as a revisional procedure after failed different restrictive procedures. The EWL was almost double in favour of MGB-OAGB in a study by WJ Lee comparing conversion of failed sleeve to MGB-OAGB and RYGB. However, in other studies, EWL was close between MGB-OAGB and RYGB in the first year but starting the second year the EWL was significantly better in the MGB-OAGB group.

“The OAGB procedure is more effective then RYGB and sleeve regarding weight loss and comorbidity resolution because it is more metabolic, but does have a greater chance of malnutrition,” Dr Fawal concluded. “It is important to remember the significance of a long pouch and balanced limb lengths. Although OAGB is recognised by IFSO, we need more prospective long-term studies to answer the concerns of BP limb length and its relation to protein malnutrition and biliary reflux and it's long term sequelae.”

Results according age and BMI

Dr Nasser Sakran (Israel) said that there are several acceptable bariatric surgical options available and the type of surgery is chosen by the surgeon based on experience, literature reports, local condition and the surgical trends in each country.

A national (Israel) bariatric surgery registry was established at the Israel Center for Disease Control, with the purpose of compiling data on all bariatric surgeries performed in all treating centres in the country. The registry began operating in June 2013 and includes data from 31 medical centres.

Data from the registry shows that since MGB/OAGB was introduced into Israel in 2014, the number of procedures has risen dramatically and it is now the most popular procedure in the country, accounting for approximately 46% of all bariatric procedures, despite the fact overall procedures are declining.

Nasser Sakran

“In Israel, the decline in sleeve gastrectomy procedures has occurred for several reasons including the risk of stapleline leaks, weight regain and Barrett’s oesophagus,” Dr Sakran explained. “The MGB/OAGB is preferred to RYGB as it is considered an easier, far less complex procedure and has a shorter operating time.”

Sakran said the data on the role of OAGB-MGB in super obese patients, geriatric and adolescence is scarce.

In summary, the results (according BMI) in super obese patients:

OAGB-MGB has been found to be a technically easier procedure in super obese patients and has significantly better weight loss compared to LSG and LRYGB in super-super obese patients.

Sakran said there are few publications about the OAGB-MGB in patients with BMI<35, although the results show that OAGB-MGB is a safe alternative to RYGB, with similar success in weight loss and resolution of metabolic complications.

“Whereas several papers have been published regarding the assessment of bariatric surgery in geriatric patients, there remain concerns regarding the operative morbidity and mortality and the adequacy of weight due to the relative immobility of older patients,” he concluded.

In children and adolescent, considering the low response to clinical treatment and lowered life expectancy of severely. However, there are still concerns about safety, effectiveness, the possibility of long-term complications, and adverse effects on growth and maturation.

OAGB-MGB is an effective in terms of weight loss, also strongly improved coexisting comorbidities in adolescents. Additionally, mid and long-term complications after OAGB-MGB is less frequent compared with LSG, LRYGB and LAGB which may also impact the patient's adherence to follow-up instructions.

Comorbidities improvement

Maurizio De Luca (Italy) claimed that the initial suspicions regarding MGB/OAGB have been overcome and now it is recognised as a valid bariatric operation. He said the effectiveness of MGB/OAGB in achieving comorbidity improvements has been shown in several studies and, in some cases, superiority over other techniques.

He cited Wang et al. published a meta-analysis comparing the efficacy between mini gastric bypass (MGB) and sleeve gastrectomy (SG) in terms of weight loss and resolution of obesity related comorbidities [2]. They concluded that MGB achieved better results both in terms of weight loss and Type 2 Diabetes (T2DM), hypertension and obstructive sleep apnoea (OSA) resolution.

Another meta-analysis by Wang et al (Comparison of safety and effectiveness between laparoscopic mini-gastric bypass and laparoscopic sleeve gastrectomy: A meta-analysis and systematic review. Medicine (Baltimore). 2017 Dec;96(50)), compared MGB and RYGB, and the former demonstrated better weight loss and better T2DM resolution.

De Luca

De Luca identified two randomised controlled trials that compared MGB/OAGB and sleeve gastrectomy. The first by Seetharamaiah et al. showed that although there were no differences in terms of % weight loss, hypertension remission and quality of life, MGB/OAGB has better outcome in terms of T2DM remission after one year. The second by trial Ruiz-Tovar et al revealed that OAGB resulted in a better short- and long-term resolution of T2DM, hypertension and dyslipidaemia than sleeve gastrectomy.

He also identified two randomised controlled trials that compared MGB/OAGB and RYGB,

Lee et al (2005) comparing the outcomes from 80 patients each (40 in each group) over two years and revealed MGB/OAGB achieved at least the same resolution of comorbidities of RYGB. The second study by Ruiz-Tovar et al showed OAGB had better resolution of comorbidities rates, compared with RYGB. Five years after surgery, OAGB patients maintained normal BMI range whereas some sleeve and RYGB patients presented with mean BMI in range of obesity.

“MGB/OAGB seems to achieve better resolution of obesity-related comorbidities, when compared to LSG and RYGB,” he added. “Evidence provided by literature is still poor and some controversies remain open. We strongly recommend more randomised controlled trials.”

GERD and hiatal hernia

Past-President of IFSO, Professor Jacques Himpens (Belgium) began by stating that there is a definite correlation between significant obesity and GERD. He explained that in the MGB/OAGB procedure, the gastro-enteral anastomosis is exposed to a mixture of foodstuffs and digestive juices such as gastric, hepatic (bile) and pancreatic secretions,

“Consequently, the danger exists that the stomach pouch not only will react to the digestive juices (gastritis), but, in addition, these juices may reflux into the oesophagus, causing GERD,” he added. “It is therefore a common concern that OAGB/MGB might be a GERD inducing procedure and be linked with the appearance of oesophageal cancer, although there have been no reports of gastric pouch or oesophageal cancer, except for one publication."

Jacques Himpens

Regarding hiatal hernia, Professor Himpens said that it makes sense to repair when present, avoiding late herniation of the pouch or of the gastric remnant.

Utilising tests such as PH-metry, impedance-metry and oesophageal high-resolution manometry should be adopted to evaluate the location and continence of the lower oesophageal sphincter. However, the literature data on GERD specifically after OAGB/MGB are rather scarce, he explained.

“MGB is a low-pressure system and the issue of GERD after OAGB/MGB appears to be less of a concern than initially thought,” he concluded. “Bile gastritis is probably more frequent, but the exact pathologic implications are not yet known.”

Quality of life (QoL)

Professor Rui Ribeiro (Portugal) said that in obese patients health-related QoL is usually impaired in both personal and group dimensions, about physical, mental and social condition and bariatric surgery significantly improves the basal very weak HRQoL of patients with severe obesity, more than conservative approaches. Furthermore, improvements in QoL has a direct relation with the amount of weight loss and has been extended to mental status with reduction of depressive symptoms and self-esteem increase.

Rui Ribeiro

He added that there is a paucity of data about HRQoL in patients submitted to MGB/OAGB, but this limited data confirm the same advantages as data from other bariatric procedures. In summary:

  • Lee YC et al. reported patients had improvement in three domains of the questionnaire (social function, physical status and emotional status) but not in gastrointestinal symptoms.
  • Bruzzi at al. reported postoperative GIQLI score of the treatment group was significantly higher than preoperative score of the control group (110.3±17.4 vs. 92.5±15.9, p<0.001). Social, psychological and physical functions were significantly increased.
  • Taha O and Abuzeid M assessed 1,520 patients and reported that there were improvements in physical condition, patient’s relationships, depressive symptoms/anti-depressive medication, self-esteem and sexual activity.

“In summary the MGB seems to offer the patient at least the same HRQoL of other surgeries, being simpler and probably safer in the perioperative period. The physical, social, psychological, sexual and mental functions improve a lot and the comorbidities resolution is good,” he added. “More studies are necessary to address in a more accurate vision the improvement in HRQoL patients may benefit after MGB/OAGB.”

Work up and preparation of the surgical patient

Dr Cesare Peraglie (USA) stated that as with any other surgical procedure, proper patient selection, workup and preparation/education are keys to ensuring outcomes in the peri and post-operative period.

All patients are evaluated and cleared from a medical and psychological standpoint with referral to other specialities such as Cardiology and Pulmonology as indicated. Pre-operative laboratory testing is done including certain vitamin and mineral levels that may need correction prior to surgery. Lastly, all patients are mandated to stop all soda, alcohol and smoking prior to surgery

In addition to the clearances, one of the most important aspects to ensure excellent outcomes and long-term results is patient education.

Cesare Peraglie

It is critical for patients to understand the procedure they are having done and how to take care of themselves after surgery. They need to know what to eat, how to eat and what to avoid that may lead to complications and worse results in the future.

Much of this is presented by means of an informed consent that aids the educational process, manages (realistic) expectations (include partners/family in the process) and outlines the risk/benefits of surgery. This is combined with pre and postoperative instructions that outline recommendations on diet and post-operative supplements.

Lastly, maintaining follow up with physicians and through social groups is extremely important and aids in the long-term management and success of the patient.

Dr Cesare Peraglie added that all his patients undergo complete preoperative medical clearance (medical and Psychological), routine laboratory and nutritional evaluation, as well as consultation with other specialists (nutrition, psychology, GI etc) for the purpose of screening and testing. Prior to surgery, they are provided with educational materials to assist them with the information to guide them through the pre and post -operative course.

Possible contraindications

Discussing the possible contraindications to MGB/OAGB, Dr Priscila Antozzi (Argentina) said that there are absolute contraindications for all bariatric surgical procedures including:

  • Unacceptable anaesthesiological risk
  • Pregnancy
  • Active known cancer
  • Active intra-abdominal infection
  • Liver cirrhosis CHILD C
  • Unstable psychopathological conditions; and
  • Active drug dependency

In addition, there are relative contraindications for bariatric surgery, including:

  • Inadequate drug treatment of pre-existing endocrine medical conditions
  • Smoking
  • Low socio-economical status or absence of health insurance
  • Anemia and nutritional deficiencies

She then outlined specific contraindications for MGB/OAGB, which included:

Priscila Antozzi

  • Crohn’s disease and Inflammatory Bowel disease – as it is not possible to predict when and which patterns this autoimmune disease will affect the small intestine, the available evidence seems to suggest sleeve gastrectomy is the preferred procedure for morbidly obese IBD patients in order to avoid intestinal manipulation
  • Primary short bowel (total small intestine length <350 cm) or secondary short bowel syndrome (after intestinal resections)

“When performed accurately, MGB/OAGB is a safe and effective procedure, however standardisation of the technique is mandatory. Possible contraindications related strictly to the technique seem to be null,” concluded Dr Antozzi. “However special recommendations should be taken as advise in order to avoid short- and long-term consequences. Those relative contraindications are a short small bowel (<350–400 cm), inflammatory small bowel disease or Crohn´s disease and low socio-economical status.”

To read the report from the first session, 'Fundamentals of OAGB-MGB' (part 1) of the report from the IFSO International Consensus Conference on OAGB-MGB, please click here

To read the report from the third session, 'Technical Systematization' (part 3) of the report from the IFSO International Consensus Conference on OAGB-MGB, please click here

To read the report from the fourth session, 'Complications/Controversies: Diagnosis, Treatment and Prevention' (part 4) of the report from the IFSO International Consensus Conference on OAGB-MGB, please click here

To read the report from the fifth session, 'Revision, Use as Revisional Surgery and Follow Up' (part 5) of the report from the IFSO International Consensus Conference on OAGB-MGB, please click here

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