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IFSO Consensus Conference on OAGB-MGB

IFSO International Consensus Conference on OAGB-MGB (part 5)

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: 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 fifth session - Revision, Use as Revisional Surgery and Follow Up.

Module V: Revision, Use as Revisional Surgery and Follow Up

Biliary complication after one anastomosis gastric bypass

Presenting on behalf of Professor Wendy Brown, Dr Nick Williams (Australia) said that although the development of gallstones following bariatric surgery is common (30-50%), symptomatic gallstone disease requiring cholecystectomy after bariatric surgery is less common with the highest rates after RYGB (6.1%- 10.6%) followed by sleeve gastrectomy (3.5% -6.1%) and the lowest rates after LAGB (0-2.9%). The rate of cholecystectomy after OAGB was 2% OAGB in a single series, although this series is limited by small numbers (n=47, 6 developing gallstones, 2 becoming symptomatic). 

Wendy Brown

Because of the frequency of gallstone disease following bariatric surgery, and the potential difficulty accessing the biliary system endoscopically post-procedure, routine concurrent cholecystectomy at the time of the index bariatric procedure has been recommended by some for all patients particularly for the bypass procedures. Others recommend routine ultrasound and concurrent cholecystectomy for all those with proven gallstones prior to the index operation, whilst others argue that concurrent cholecystectomy is not justified for asymptomatic stones due to the relatively low rate of symptoms after bariatric surgery and the risk that a concurrent cholecystectomy adds to the bariatric procedure.

Nick Williams

Although gallstones can be prevented with Ursodexycholic acid (UDCA), only five randomised trials have studied the impact of UDCA and these did not provide definite evidence regarding its use. As 6080% of patients with gallstones will remain asymptomatic.

“The current evidence suggests that it is not cost effective to offer routine concurrent cholecystectomy due to the low frequency of cholecystectomy after bariatric procedure. Concurrent cholecystectomy at the time of bariatric surgery maybe justified for those with symptomatic gallstone disease prior to the bariatric procedure, however, the surgeon should consider if this is best done along with the bariatric procedure or prior to the bariatric procedure to reduce the operative risk,”” he concluded. “There is little information about gallstones following OAGB, however, it is likely that the information available for RYGB will translate to the OAGB procedure, although access to the biliary tree is more difficult after OAGB.” 

OAGB-MGB weight regain and indications for revisional Surgery

In his presentation Dr Ali Khammas (UAE) questioned the need for revisions in many of the reported reasons - especially for leaks, stenosis and ulcer perforation where he believes other less invasive methods have demonstrated successful outcomes whilst maintaining the OAGB configuration.  He added that weight regain and rates of weight regain reported in literature are low and in these results were confirmed in his own series of 113 superobese after six years follow up.

Ali Khammas

Dr Khammas then described his own centres techniques when revising OAGB for weight regain, which he calls the ‘Triple attack’ approach. This approach involves sleeving the pouch, reducing the size of anastomosis and extending the biliary limb to be approximately one third of the total limb length.

“Conversion to RYGB is rarely needed in cases of leaks and perforations,” he concluded. “Weight regain after OAGB-MGB is low but is a fact and requires a balanced approach, and it is important to remember that when revising OAGB/MGB all components need to be addressed.”

Techniques for revising OAGB/MGB

Dr Ahmad Bashir (Jordan) stated that there are several reasons for OAGB/MGB revision including leak, stenosis, ulcer perforation, severe weight loss, intractable malnutrition, weight regain, failure of weight loss and reflux. He said that there are many definitions used for weight regain after OAGB or bariatric surgery which can be summarised (Baig et al, Obesity Surgery 2019) as:

  • Regain of more than 25% of lost weight from the nadir weight
  • Regain of more than 10 kg from the nadir weight; and
  • Regain of more than 5 BMI points from the nadir weight

However, weight regain and inadequate weight loss so far are not reported frequently and revising the gastric pouch seems to result in a decent short-term outcome with no long-term follow up to date (33% EWL at 3 years by Faul et al, Obesity Surgery 2019).

Ahmad Bashir

Of the main complications with increasing concern after OAGB are malnutrition and hypoalbuminemia, as well as bile or acid reflux on long-term follow up, and all are reasons for revision. However, even acute complications such as leak, have been described as indication for revising OAGB.

For complications, conversion to RYGB seems to be the most common form, but surgeons must be familiar with RYGB conversion techniques to avoid further negative sequela. Therefore, it is important that they measure the common channel limb (CCL), ensuring it has adequate length if the Biliopancreatic limb (BPL) remains the same. Lengthening the CCL or reversal to normal anatomy are the options in patients with malnutrition.

“We propose the below protocol in reporting data to help us collect and understand what needs to be done better in the future,” he concluded. “Surgeons are encouraged to report the following technical aspects, in addition to all other routine demographics, weight parameters and nutritional status: Gastric pouch length and width with stoma size on CT imaging and endoscopy, and intraoperative findings of Pouch length, width and total small bowel length, and CCL & BPL measurements with new revision measurements”

Use of OAGB-MGB as a revisional surgery

Moataz Bashah (Qatar) looked OAGB-MGB as a revisional surgery and compared the outcomes from revisional OAGB vs revisional RYGB, revisional SADI and revisional sleeve gastrectomy. He said that revisional surgery is increasingly in demand in bariatric centres, especially after failed restrictive surgery.

Moataz Bashah

He noted that is limited evidence in the literature although Chevallier et al ((Surg Obes Rela t Dis 2016;12:240–245), who compared primary single anastomosis gastric bypass (SAGB) with revisional SAGB, concluded that five years revisional SAGB for a failed restrictive procedure was safe and effective, but quality of life and upper gastrointestinal function were lower compared with primary SAGB. Mario Musella et al (Surgery for Obesity and Related Diseases. 2019) reported that OAGB is a safe and effective revisional procedure after failed LSG and LAGB, and Che et al (Obesity Surgery 2018) reported that both SAGB and RYGB are acceptable options for revising a restrictive type of bariatric procedures, although revisional SAGB was shown to be a simpler procedure with better weight reduction than revisional RYGB but anaemia is a considerable complication at long-term follow-up.

Other revisional procedures, such as single-anastomosis duodenoileal (SADI) bypass has found to be a safe operation that offers satisfactory weight loss for patients subjected to a previous sleeve gastrectomy, the side effects are well tolerated and complications are minimal (Torres et al. Surg Obes Relat Dis2015;11:351–355).

“Revisional OAGB-MGB is technically easier procedure and has better outcomes compared to revisional RYGB, but comparable result with revisional SADI,” he concluded. “Revisional OAGB-MGB is a robust revisional bariatric procedure in properly selected patients. However, issues around hypo-absorption and reflux need to be addressed.”

Proposals for medical follow-up

Khalid Mirza Gari

Khalid Mirza Gari (Saudi Arabia) said that OAGB-MGB are restrictive malabsorptive bariatric procedures, associated with nutritional deficiencies that are directly proportional to the biliopancreatic limb (BPL). However, nutrient deficiencies exist in the morbidly obese population before surgical intervention, suggesting that they result not only from the surgical reduction of absorptive area and the rapid weight loss, but also because of a pre-existent form of malnutrition.

Therefore, he proposed this medical follow up protocol:

Preoperative correction of malnutrition and comorbidities

  • Vitamin B1 and B12, vitamin D
  • Calcium               
  • Eradication of H.Pylori.
  • Endoscopy

Post-operative follow-up

  • 1st year: 3 moths, 6 months, 9 months and 12 months
  • 2nd year: every six months
  • Annually
  • Vitamin B1 and B12, vitamin D monitoring and adjusting the dosage.
  • Hb level (anaemia) calcium, PTH monitoring and correlation of calcium, SL
  • Close monitoring of LFT, Protein and albumin to prevent severe protein-calorie malnutrition
  • Early ultrasound follow-up at 6 months, 9 months, for cholecystitis as early symptomatic if cholecystectomy not done concomitant with MGB
  • Endoscopy after one year and at three years.

Postoperative use PPI after bypass surgeries

Arun Prasad (India) began by stating that marginal ulceration after gastric bypass surgery is a recognised complication and has been reported in 1–16 % of patients after gastric bypass surgery. Various authors have reported the same after MGB-OAGB (Rutledge, Mahawar et al)

Arun Prasad

There is evidence that acidity may play a role in the disease pathophysiology and it is a common practice for bariatric surgeons to begin a prophylactic course of proton pump inhibitors (PPI), postoperatively.

The pathology is a result of acid insult to the relatively unprotected jejunal mucosa. He said that several mechanisms have been implicated in a marginal ulcers development, namely:

  • Large pouch size (leading to a larger parietal cell mass in the pouch and resulting acid exposure)
  • NSAIDs and smoking
  • Mucosal ischaemia
  • Gastrogastric fistula (remnant stomach parietal cells producing acid which enters pouch leading to exposure of the jejunal mucosa to a higher acid level)
  • Foreign body reaction (staples and sutures)
  • Preoperative colonisation of Helicobacter pylori

It is a common practice for bariatric surgeons to begin a prophylactic course of proton pump inhibitors (PPI) after gastric bypass however, high-level evidence supporting its benefits is lacking from literature.

The timing of marginal ulcers presentation has classically been divided into an early and late presentation. It has been hypothesized that early MU are caused by ischemic changes at the anastomotic site, while late MU result from increased acid production. Routine usage of PPIs reduced the occurrence of marginal ulceration after LRYGB.

Usage after MGB-OAGB has been suggested to reduce MU, but duration of usage is unclear. Most surgeons doing MGB-OAGB recommend administration of PPI for about 6 months as was seen during the consensus meeting at Hamburg ( July 18-19, 2019 )

“Despite the limitations of the current systematic review and meta-analysis, the data suggest a significant incremental benefit of prophylactic PPI in reducing marginal ulcer after all gastric bypass surgeries,” concluded Prasad. “The question still remains as to the optimal duration of PPI prophylaxis. Prospective randomised trials would provide more robust evidence to support the routine use of PPI prophylaxis and may help guide duration.”

Optimum MDT follow up

Dr Muffazal Lakdawala (India) said the most important requirement is the need for a multi-disciplinary team. The case for comprehensive care in the field of obesity could never be more apt for delivering effective, quality, safe, and comprehensive care to the surgical bariatric patient. The various advantages of a MDT approach include improving treatment outcomes, better quality of life, higher quality of holistic healthcare, faster recovery rates, maximisation of functional ability to name a few.

Muffazal Lakdawala

There are various members of any MDT from obesity medicine specialists, to anaesthesiologists, endocrinologists, hepatologists, nephrologists, pulmonologists, gynaecologists, cardiologists, endoscopists, psychologists, physical trainers and nutritionists.

MDTs help to assess and optimise the right patients for bariatric surgery, provide continuous support to maintain weight loss in the long-term post-surgery, address acute and chronic post-operative complications related to bariatric surgery such as metabolic disturbances which require different skills in management. He added that they also have the potential to address the rising incidence of revisional and high-risk surgical cases and play a role in ensuring high quality short and long outcomes.

He added that it is of paramount importance that pre-operative gastroscopy is performed to rule out pre-existing conditions such as Barrett’s oesophagus, large hiatal hernias, neuro endocrine tumours, and that post-operative surveillance to rule out asymptomatic marginal ulcers and bile gastritis/oesophagitis.

“OAGB remains an emerging procedure in the field of bariatric surgery with its own set of challenges such as Steatorrhea, dumping, nutritional sequelae depending on length of BPL bypassed and other problems like marginal ulcers and bile reflux leading to impaired quality of life in some patients,” he explained. “It is therefore a procedure that needs a close follow up, to pick up and treat some of these problems before they become significant. To conclude a bariatric surgical practice without an MDT team is a recipe for disaster.”

Nutritional supplementation guidelines

Professor Gerhard Prager (Austria) explained that the majority of the published nutritional guidelines focus on post-operative supplementation and give no specific recommendations for MGB-OAGB. By lengthening the Biliopancreatic Limb (BPL) compared to the Roux-en-Y Gastric Bypass (RYGB) the risk for additional deficiencies might rise, as many vitamins and micronutrients are absorbed in the duodenum and jejunum.

Gerhard Prager

He cautioned that supplementation should start prior to any bariatric/metabolic procedure with Vitamin D, Calcium and Iron being the most common deficiencies due to an imbalanced diet, the fatty tissue acting as an endocrine organ and fatty liver disease/fibrosis as an additional risk factor to develop vitamin D deficiency. He added that protein malnutrition seems to be an underestimated problem.

Several randomised studies compared either RYGB with OAGB/MGB or OAGB/MGB with different limb lengths:

  • Lee at al. reported serum albumin levels showed no difference between both groups
  • Data from the YOMEGA Trial showed that 21.4% severe nutritional complications were seen in the OAGB group vs. none in the RYGB group (p=0.0034). Higher incidences of diarrhea, steatorrhea, and nutritional adverse events were observed with a 200 cm BPL-OAGB, suggesting a malabsorptive effect.
  • Komaei et al. compared 2 different groups after OAGB (fixed 200cm BPL group with a second tailored group, BPL=40% of small bowel length). Weight loss and iron deficiency did not differ between both groups, but the tailored group had significantly less Vitamin A, D3 and Albumin deficiencies.

“Additional care must be taken for BPL>200cm in terms of protein malnutrition and liver problems. These can also occur several years after the operation and lead to substantial harm or even death,” he said. “Based on the current literature a BPL length of less than 200cm seems to be favourable in terms of an acceptable (low) rate of vitamin/micronutrients deficiency and protein malnutrition.”

When to choose OAGB-MGB or RYGB as revisional surgery

Past-President of IFSO, Dr Kelvin Higa (USA), said that both OAGB-MGB and GBP are primarily done as salvage or rescue from gastric banding, sleeve gastrectomy and vertical banded gastroplasty for inadequate weight loss, weight regain, or GERD.

Kelvin Higa

He said that there is a paucity of data with no randomised controlled studies, a low number of procedures and studies, and heterogeneity of the target procedure (eg pouch size/orientation, variation in length of the limbs in GBP and of the BP limb lengths in OAGB), few studies reporting nutritional data and no quality of life data. There is also no standardisation of measurement technique however, he added in carrying out a review of the available literature shows that there are trends that seem to emerge regarding weight loss, complications, GERD and comorbidity resolution.

“When compared with RYGB, weight loss and resolution of comorbidities are better for OAGB with a reduced operative time and complications,” he added. “However, GERD is better for RYGB, but nutrition and GI (GERD/diarrhoea) symptoms, which are dependent on total bowel and BP limb lengths, are not consistently reported for either procedure.”

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 second session, 'Indications and Selection of Patients' (part 2) 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

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