This blog provides free general information for anyone who is seeking to understand more about the problems with obesity, bariatric surgical procedures and its long term failures, not intended as a medical consult. Please seek proper medical advice for individual assessment and management.

Please read the other section on Bariatric Surgery Summary 2022 and Caveats of bariatric surgery for more information.

Understanding obesity as a significant and chronic health disease

Globally obesity is a major public health problem. Worldwide the prevalence of obesity has tripled from 1980 to 2015 (estimated 1.9 billion people are currently obese) and obesity accounted for over 4 million deaths.

Obesity is a chronic, progressive and relapsing disease with associated medical co-morbidities.

• Even after successful weight loss results (with dieting or exercise alone) or surgery there will be potential for weight regain and return of medical co-morbidities with time.

Obesity increases metabolic risk factors and is linked to common chronic health conditions (especially HPT, T2DM, dyslipidaemia), obstructive sleep apnoea, ischemic heart disease, fatty liver disease (NASH), chronic renal disease, depression and many others.

• With weight regain some of these medical conditions (such as HPT, T2DM) may return.

Obesity is a known risk factor for many cancers due to the chronic inflammation, adipokine dysregulation, insulin resistance and alteration in the immune system. 

• Obesity related cancers include breast, endometrial, ovarian, liver, pancreas, biliary, colorectal, GOJ cancers and multiple myeloma.

Bariatric surgery has been reported to reduce HER-2 positive breast cancers. 

Obesity is a risk factor for endometrial hyperplasia and Type 1 endometrial adenocarcinoma.

• Patients who had bariatric surgery obviously have a lower BMI at the time of treatment for endometrial cancer and are more likely to have minimally invasive hysterectomy.

Bariatric Surgery

Bariatric surgery is the most effective treatment for obesity and obesity related medical co-morbidities. 

• Unlike conservative non operative management, bariatric surgery is more permanent (some procedures are also irreversible) 
• Bariatric surgery works as a combination of restriction, changes in gut hormones secretion, bile acid metabolism, intestinal bacteria colonization and causing epigenetic changes.

By 2014 the laparoscopic sleeve gastrectomy has become the most widely performed bariatric procedure in the world. 

• In 2016 LSG accounts for more than 50% of all bariatric interventions.
• In 2022 the RYGBP and OAGB have become the next two most common following the LSG.

Treatment of obesity and associated medical conditions have a huge impact on healthcare budget to treat all the medical co-morbidities and complications mentioned above.

The return on the financial investment in laparoscopic bariatric surgery procedure is recovered in 2-3 years after surgery. 

• The mid/long term cost saving is in the reduction in health care cost to treat HPT, T2DM, coronary heart disease, OSA, depression and various cancers.
• Bariatric surgery also helps to reduce premature cardiovascular mortality, all cause mortality and cancer incidences. 

Indirect cost of obesity includes absenteeism and presenteeism (reduce productivity at work). 

Bariatric surgery risks

However the risk benefit ratio for each patient needs to be assessed carefully and the surgery needs to be worthwhile in terms of achieving the goals set out, especially in terms of realistic weight loss, resolution of medical co-morbidities, health/functional improvement in quality of life and extending life expectancy.

For example bariatric surgery is not recommended for advanced age patient with non reversible end stage medical co-morbidities and already well established complications of obesity.

For example with the chronicity of T2DM (over 5 years) and being on insulin for years or a decade, the diabetes will not be reversible.

Bariatric surgery has 5- 10% serious post operative complication and 0.5% mortality rate

• Revision bariatric surgery in particular have a much higher risk especially for leaks, bleeding and post op mortality

Hospital re-admissions in the short and long term

After RYGBP there is up to 11% representation to the emergency department.

And 6% hospital re-admission rates mostly occur in the first 30 days after surgery. 

• Commonly this is due to vomiting, dehydration and abdominal pain.

Others report that after bariatric surgery up to 1/3 of patients represent to the emergency department and 1/5 was re-admitted in the first 90 days after surgery.

After the LSG there can be intra thoracic migration of the sleeve. 

• This is a unique problem with the sleeve.
• The patient may require surgery to repair the hiatus hernia.

Hospital emergency department presentations may also increase with time from surgery 

• Maybe up to 30% within the first 3 years and for some patients ended up with multiple re-admissions to hospital. 
• Commonly this is due to abdominal pain, causes may include internal hernia, small bowel obstruction, marginal ulcers at the GOJ and gall stones.
• Marginal ulcers have been reported to occur from 0.5 to 16% after RYGBP.

In the long term other problems such as diarrhoea, anaemia, hypoglycaemia, dumping, fatigue may be present as well.

Acid and alkaline/bile reflux

After LSG the risk for denovo reflux has been reported in 20-26% and maybe up to 1/3 of cases

• Risk factors include older patients, smokers, higher BMI

Some of the patients may already have reflux before the sleeve 

• After weight loss the reflux symptoms improved in maybe up to 1/5 of the patients
• After LSG conversion to RYGBP there may be up to 75% resolution of reflux symptoms 

After OAGB there may be more issues with micronutrient deficiencies and bile reflux compare to the sleeve and RYGBP

• GOR have been reported in up to 30% after OAGB
• Bile reflux resistant to medical treatment may need correctional surgery to a RYGBP with or without pouch resizing/shortening, Braun’s jejuno-jenunostomy or conversion to a proper Roux Y reconstruction.

Reflux has also been reported after primary RYGBP in the long term as well

• Some report 50% of patients may have recurrent GERD at 10 years follow up after RYGBP
• Often patients need a CT scan to check for hiatus hernia, small bowel obstruction and internal hernia as well as a gastroscopy to check for marginal ulcers or anastomotic strictures

Surgical complications

Marginal ulcers have been reported in up to 5% after RYGBP and OAGB. 

Risk for marginal ulcers include cigarette/alcohol consumption, NSAIDs or steroid use and Helicobacter pylori.

• Some patients need prophylactic PPI medications for 6 months or longer to prevent marginal ulcers.
• After the development of ulcers, follow up surveillance gastroscopy and PPI medications may be required for life.
• Some patients may need post op gastroscopy 1 to 3 years (after sleeve or bypass) to check for ulcers, erosive oesophagitis, Barrett’s oesophagus or other pathology.

Gastro-gastric fistula have been reported after RYGBP. 

• This may result in marginal ulcers, abdominal pain, reflux and weight recidivism.

After RYGBP internal hernia can occur in the inter-mesenteric small bowel defect and Petersen’s space, reported to occur in up to 12% of cases. 

• This may lead to small bowel obstruction, ischemia, necrosis and perforation in severe cases or chronic pain, nausea/vomiting or other gut issues. 
• Internal hernia in a pregnant lady may require emergency surgery and can result in maternal or fetal deaths.

Internal hernia is less common after OAGB but may still occur in up to 2.8%.

Rapid weight loss may lead to gallstone formation. 

• It is uncertain whether ursodeoxycholic acid prophylaxis is necessary for the 6 months after surgery.

Macro and micronutrient deficiencies after bariatric surgery

Some report up to 1/3 bariatric surgery (bypass or malabsorptive procedures) patients may develop post prandial hyperinsulinaemic hypoglycemia and severe cases in up to 12% of patients. 

• Hypoglycemia may contribute to weight regain with time due to cravings and the need to eat frequently 
• This is more likely to occur in the younger female population group, greater amount of post op weight loss and those with higher insulin sensitivity. 
• Diagnosis is difficult requiring a mixed meal provocation test and patients meeting the Whipple’s triad.

Micronutrient deficiencies are often reported with RYGBP and OAGB, mainly for iron, ferritin, B12, D and iPTH. 

• Worst with OAGB (see below)

OAGB has been reported to have more diarrhoea, steatorrhoea, nutritional deficiencies and bile reflux oesophagitis (especially after 1 year) and revisional surgery is required in severe cases.

Recent multicentre trial reported non inferiority weight loss results with OAGB (YOMEGA) compared to RYGBP, with comparable resolution of metabolic disorders. 

• But the prevalence of nutritional disorders is higher in OAGB (21% of cases). 
• Other reports more anaemia (44% vs 17%), hypoalbuminaemia (32% vs 15%) and hypocalcemia (19% vs 8%) comparing OAGB to RYGBP.
• Protein energy malnutrition have been reported in the OAGB with a longer BP length limb over 150-200cm. 

Hair loss in younger women may be associated with low levels of Zinc, folic acid and ferritin +/- iron. 

• Hair loss may occur in up to 40-60% of post op patients after massive rapid weight loss in the first 6 months after LSG and gastric bypass. 
• Hair loss may decrease with time.

Micronutrient deficiencies can also occur after LSG not just for the bypass patients.

• After LSG it has been reported that there may be deficiencies in vitamin D (up to 89%), B12 (up to 26%0, iron (up to 43%) and PTH elevation (up to 39%) in the first year post op.

• After LSG the causes of nutritional deficiencies are not related to the bypassed intestinal segments.
• The causes are multifactorial, which include reduced dietary intake, decreased gastric acid and intrinsic factor secretion, poor food choices and food intolerances.
• The micronutrient are more easily corrected.

Malnutrition

Protein calorie malnutrition after gastric bypass or some malabsorptive operations are rare (less than 2%) but they are extremely serious. 

• Liver failure and death may result in some cases.

Patients with severe refractory hypoalbuminaemia may need complete reversal of the bariatric procedure.

After gastric bypass multiple blood tests are required to check for macronutrient and micronutrient deficiency. 

• Often blood tests (albumin, LFT) are done 3 monthly for the 1^st year, 6 monthly for the 2^nd year and yearly after that for life.
• Patients need a great general practitioner and dietitian to care for them in the long term as a shared care model with the surgeon or hospital.

The minimal requirement for micronutrient supplements includes iron, B12, folate, calcium, vitamin D, Zinc and copper for life.

Inadequate weight loss or weight loss failure

Definitions:

• Insufficient weight loss refers to <50% EWL after 2 years
• Weight regain refers to a regain >25% EWL from the lowest point (nadir) after surgery and this may be an indication for revision surgery

The results for revision surgery for inadequate weight loss are often disappointing

• Inadequate weight loss may be due to other biological/physiological factors not related to the technical aspects of the surgery

The results for revision surgery for weight regain years later on the other hand may achieve better or moderate results but the weight loss result often will not be as good as the primary weight loss procedure.

Also please note revision bariatric surgery have more risk and complications, especially for leaks, fistula, abscess, bleeding, etc. 

• It is not to be taken lightly. 

Weight regain

Revision surgery rates after LSG has been reported up to 20% maybe more in the future with longer follow up data.

It is estimated that more than 80% of revision bariatric surgery is for inadequate weight loss and weight regain.

Revision surgery is usually performed on average after 5.6 years (range 1-17 years).

Revisional OAGB or RYGBP procedures almost always result in less weight loss than the primary weight loss procedure

After LSG and sometimes gastric bypass procedures for patients with a loss of restriction, the gastric pouch can be assessed with a CT fizzogram

• If it is dilated (width is >4cm) the patient may request for gastric pouch resizing

Conversion LSG to OAGB is more common in some centres for weight regain.

• Conversion LSG to OAGB for reflux is controversial especially because of the incidence of bile reflux, erosive oesophagitis and GOJ adenocarcinoma

Conversion LSG to RYGBP is more common for weight regain and reflux.

• The risk for denovo reflux after LSG has been reported up to 20-26%
• Some of the patients did have reflux before the sleeve as well
• There is up to 75% resolution of reflux symptoms after LSG to RYGBP

One study compared OAGB to SADI-S after LSG for weight regain (in those BMI>50) 

Found 80% EWL (40% TWL) with better results in the SADI group but there were no statistical differences between the two.

LSG conversion to OAGB has better weight loss (%TWL) result than RYGBP.

• Most of the OAGB are planned if there are inadequate weight loss within/after the first year

Once again revision bariatric procedures are not to be taken lightly, it has less than optimal weight loss results 

• The risk and complications goes up significantly compare to the primary procedure 
• The long term side gut and nutritional side effects increases with time and may persist for life

Patient enquiries about Bariatric surgery at Gold Coast Private Hospital Specialist Suites

What is your weight, height and BMI ?

Please note:

For the Caucasian population, Medicare will only approve bariatric surgery for

• Patients with a BMI>40
• or BMI>35 with medical problems (such as diabetes, high blood pressure, high cholesterol, cardiovascular disease, severe sleep apnoea or cancer (breast, endometrial, bowel))

The recommended age range is usually between 18 to 65 years.

Younger female patients should consider finishing their family first before having weight loss surgery.

• Some patients outside this range may be approved for surgery depending on clinical grounds
• But patients in the older age range may not benefit from weight loss surgery, the body weight loss is less, the chronic medical conditions may not be reversible and the permanent damage (long term insulin requiring diabetes, heart attack, degenerative joint disease, etc) may not resolve after surgery

We don’t know where you live

• I have stopped accepting patients from other states or. capital cities.
  • There are plenty of good bariatric surgeons in the major centres already, please see one of the surgeons there
  • Only concentrating on providing service for patients from coastal and country Queensland and Northern Rivers NSW

If you already have a surgeon in the past, please return to see your original surgical team. It is professional courtesy that I don’t steal patients from my colleagues.

Costs:

Please make sure that the health fund will cover you for:

*The sleeve gastrectomy or gastric bypass (the item number is 31575 or 31572)

You may to pay a hospital excess (that depends on your health fund)

The surgery cost $500

The assistant fee is $500 (for gastric bypass)

The anaesthetist will also charge you a small gap (~$500)

The other costs may include (medications from pharmacy, blood tests, x-rays, etc.)

If there are any complications and other specialist needs to consult, they will charge you extra.

For those travelling to the Gold Coast, obviously you will need to factor in the cost of flying or driving plus accommodation

• the stay in hospital is usually 2 days
  • (Patients from far away often stay for a week on the Gold Coast after discharge from hospital before returning home)

Please note:

• There are limitations to weight loss surgery, you won’t lose as much weight as you think (you won’t get to a BMI of 20-25)
• Weight loss surgery is drastic and not reversible
• It does have side effects and complications
• Please do your research carefully

Patients who smoke cigarettes and consume large amounts of alcohol will be rejected for surgery

Please note:

All patients have to agree to the steps below if they wish to have surgery here on the Gold Coast:

• They need to have a regular and a very good GP to do the primary assessment and post op follow up (especially after a gastric bypass).
• They need to have regular meetings with their dietician and exercise physiologist in the pre and post op period.
• They have to see a psychologist if the GP or surgeon suggested it.
• They agreed to email the surgeon to give periodic updates in 2 weeks, 3 months and 12 months.

• They need to keep their private health insurance in case more hospital/medical treatment is needed in the future (eg. surgery for gallstones or hiatus hernia/reflux).
• They need to report any post op issues and concerns early on and attempts will be made to bring the patients back to the Gold Coast.

I am seeing a trend of my past patients developing reflux, hiatus hernia and weight regain coming back for revision hiatus hernia repair and gastric bypass surgery, sometimes many years after the initial sleeve gastrectomy.

• You will need to have private health insurance to have revision surgeries done.

Phone and email follow up:

We are now part of the Bariatric Surgery Registry, the hospital employs a nurse to ring the patients periodically to follow up on the weight loss results and to identify any patients with post op problems, especially with reflux, weight regain and post op complications.

A Bariatric Physician/GP will see you or do a phone consult after the surgery, which might be 1 month, 3 to 6 or 12 months post op.

You must always keep in close contact with the surgeon via email (victorliew@live.com.au) and with the office via phone (07 5530 0770) or email (admin@gcpss.com.au). 

 

 

This blog provides free general information for anyone who is seeking to understand more about the difference between the sleeve gastrectomy and gastric bypass surgery, that is currently available for weight loss (in 2020), not intended as a medical consult. Please seek proper medical advice for individual assessment and management.

 

The crucial learning points are:

Patient often self-select the type of bariatric procedure they wish to have based on:

• The safety and efficacy of the procedure
• The advantage, disadvantage, side effects, acute and long term complications of each procedure
• Post op care (GP follow up and availability of allied health care) needs to be available for patients in remote area
  • This may include digital follow up in the post Covid-19 era
• Understand that there will be weight regain and other post op issues with any bariatric procedures and some patients may require further operative interventions in the future

 

Choosing to have a sleeve gastrectomy or gastric bypass is based on so many other clinical aspects as well, which include:

• Not just the long term weight loss result and weight regain
• Issues with Type 2 diabetes mellitus and post op reflux
• Issues with subfertility and future pregnancy
• Issues with gallstones and ERCP

 

This blog essentially discuss:

• Why it is preferable and much safer to choose a sleeve gastrectomy, especially for young females in their reproductive age group (who wish to get pregnant in the future) or are concern about the long term follow up issues with the gastric bypass.
• The issues with acid or alkaline/bile reflux and why some patients may decide to choose the Roux Y gastric bypass instead

 

This blog won’t cover every aspects in the decision making process. Patients need to do their research thoroughly, to discuss all this with their general practitioners (GP), allied health team and family members before making the correct choice.

 

 

 

 

Introduction

Bariatric Surgery in Australia

Currently (in 2020) in Australia most patients have a choice between various primary procedures, which include laparoscopic gastric band, sleeve gastrectomy, single anastomosis or omega loop gastric bypass, the Roux Y gastric bypass or the SADI-S.

 

Revision procedures may include the above or the more complex bypass procedures, which is mainly the bilio-pancreatic duodenal switch (BPD-DS) or single anastomosis duodenal-ileal bypass with sleeve gastrectomy (SADI-S), also known as the stomach intestinal pylorus preserving surgery (SIPS).

 

Nowadays the tech savvy patients are often well informed by social media, in our information rich environment and often are well inter connected, asking questions and reflecting on the experiences of other patients who had the surgery previously.

 

Patients may self select the procedure they wish to have and often also select the surgeon they wish to see.

 

It is understandable that some surgeons would perform one the above bariatric procedures in preference over the others because of how their practices have evolved over time.

• For example some practices may specialise in primary sleeve gastrectomy and some others in the complex revisional bypass procedures.

 

The role of the bariatric surgeon sometimes is about patient education, providing support, performing the bariatric procedure to tailor for the need of the individual patients or refer on to other surgical colleagues if they don’t provide the service (eg, the SADI-S).

 

Surgeons and bariatric physicians/GP need to have good knowledge of the various surgical procedures that are available and give appropriate advice. The patients then take part in the final decision making process.

 

However with the ever increasing data published and more results being available from so many research conducted around the world, it is easy to get lost amongst the vast information that is presented to the patients.

• The treating medical team can also be easily influenced by other institution’s experiences.

 

Hence in summary, the decision making process is becoming harder with so many pro and cons of each procedure to be considered.

 

Before we begin discussing the reasons to choose between the sleeve gastrectomy or gastric bypass, It is important to re-iterate that bariatric surgery is not just about achieving the maximum weight loss possible.

 

The aim of bariatric surgery is to:

• Achieve durable and maintained excess weight loss (>50% EWL) in the long term
• For the treatment (or resolution) of obesity associated co-morbidities (mainly Type 2 diabetes mellitus, hypertension, dyslipidaemia, obstructive sleep apnoea)
• To improve the quality of life (in a physical, psycho-social sense, better employment, family life and emotional well-being)
• To reduce premature cardio-vascular morbidity/mortality (fatal or non-fatal heart attacks and strokes) and increase survival (life span)

 

 

 

 

Proven scientific research

 

The published data confirmed that:

• Bariatric surgery is the most effective long term sustainable weight loss treatment for the morbidly obesity (BMI>40) patients.
• Bariatric surgery is effective for treatment of medical co-morbidities associated with obesity, with remission rates up to 92% (for type 2 diabetes mellitus), 75% (for hypertension) and 96% (for obstructive sleep apnoea).
• Bariatric surgery reduces premature cardio-vascular mortality associated with obesity.
• Weight loss surgery can help improve non alcoholic steatohepatitis (NASH), reduce albumin loss in the urine, improve kidney function and reduce chronic inflammation.
• Peri-operative mortality rates from bariatric surgery is very low, reported to be <1%.

 

 

Bariatric surgery and cancer prevention in female patients

? Only a relative indication for bariatric surgery

 

More recently there are evidence that bariatric surgery are associated with reduced obesity related cancer incidence (especially post-menopausal breast and endometrial cancers) and perhaps decreased cancer mortality.

 

Breast and endometrial cancer are highly sensitive to oestrogen levels. Visceral fat has aromatase which increases the circulating levels of oestradiol.

 

Central obesity often is a chronic inflammatory state, with increased pro-inflammatory markers (CRP, TNF-a, IL-6), which leads to a state of insulin resistance and reduced sex hormone binding globulin, which increase the bioavailability of ostrogen.

• Oestrogen is believed to be associated with tumour formation and spread (tumourogenesis and metastasis respectively).
• Rapid, significant and sustained weight loss after bariatric surgery has been shown to significantly reduce the levels of oestrogen.

 

Bariatric surgery also have other cancer reduction benefits, which may include decrease in the chronic inflammatory state, reduce inflammatory markers, alter the fat and bile salt metabolism, decrease in gut hormones, changes in metabolism, changes in gut microflora, changes in intestinal gluconeogenesis and maybe many more factors that is yet to be discovered.

 

For now we do not understand much about the role of gastric bypass and the increase or decrease rate of inflammatory colitis or colorectal cancer.

 

However it is important to stress to the referring doctors and the members of the public that cancer prevention are usually not the primary aim for patient seeking weight loss surgery.

Patients are more troubled by the increased risk of premature cardio-vascular mortality (by the age of 50 years) than mortality from breast, endometrial or other gastro-intestinal (GIT) cancers at the age of 70 years or older.

 

 

 

 

Laparoscopic sleeve gastrectomy or gastric bypass

 

After the long introduction and background information above, we should look at the 3 common bariatric operations currently available in Australia, which include laparoscopic sleeve gastrectomy (LSG), one anastomosis gastric bypass (OAGB) and Roux Y gastric bypass (RYGBP).

 

All these should be considered as permanent or not entirely reversible.

• These patients will never return to a normal full sized stomach or have the entire small intestinal length restored again.

 

There are other surgical alternatives such as the laparoscopic adjustable gastric band and the single anastomosis duodenal-ileal bypass (SADI-S).

 

There are also non-surgical or endoscopic techniques such as the gastric balloon, endoscopic sleeve gastrectomy and other innovative techniques. All these are not discussed in this section.

 

 

 

Sleeve gastrectomy versus gastric bypass

The key features for patient to understand

 

	LSG	OAGB	RYGBP
Description	About 2/3 to 3/4 of the stomach is removed, creating a long narrow tube.   The small intestine anatomy or length is not altered.	The upper stomach is narrowed into a long tube and the stomach is joint to the mid part of the small intestine (150-200cm from the duodenal jejunal flexure).   There is only one anastomosis.	The upper stomach is narrowed into a long tube and the stomach is joint to the upper part of the small intestine (>25-50cm from the duodenal jejunal flexure). The alimentary limb is > 100-150cm before it is joined to the rest of the small intestine. There are 2 anastomoses.
Average total body weight loss	30%	30-35% or more	30-35%
Estimated excess weight loss	50-60%	50-70%	50-70%
Weight regain	Weight regain does recur after 2 to 3 years.   LSG can be converted to OAGB, RYGBP or SADI.	Weight regain does recur after 3 to 5 years.     Further surgery for weight regain may or may not be possible.	Weight regain does recur after 3 to 5 years.   Further surgery for weight regain may or may not be possible.
Advantage	There is more restriction with the sleeve. Patients are less able to eat without experiencing early satiation, discomfort or nausea.   This surgery is the easiest to perform with the least complications.   Nutrients, vitamins and drugs are still able to be absorbed in the proximal small intestine.   The lowest risk for nutritional side effects.	Weight loss is from both restriction and hormonal changes in the brain gut axis.   There may be less absorption of dietary fats in the gut.   OAGB is easier to perform than the RYGBP.	Weight loss is from both restriction and hormonal changes in the brain gut axis.   There may be less absorption of dietary fats in the gut.
Disadvantage	Have more acid reflux, nausea and vomiting.   In the early stages most patients struggle to eat and take longer to recover/progress to eating solid foods.   There is a potential for long term complications of reflux, include erosive oesophagitis, peptic stricture and Barrett’s oesophagus.   Some patients may need a hiatus hernia repair and convert the LSG to RYGBP.	There is a risk for developing dumping syndrome and neuro glycopenic symptoms.   Lifelong multivitamin and mineral supplements are necessary.   Lifelong follow up with the GP and dietician with blood tests (2 to 3 times a year) is necessary.   There is a risk for marginal/stomal ulcer and anastomotic stricture, which may need gastroscopy and dilatation. Bleeding or chronic non healing gastric ulcers may need revision surgery.   There is a risk of bile/alkaline reflux. Some patients need to have the OAGB converted to RYGBP.	There is a risk for developing dumping syndrome and neuro glycopenic symptoms.   Lifelong multivitamin and mineral supplements are necessary.   Lifelong follow up with the GP and dietician with blood tests (2 to 3 times a year) is necessary.   There is a risk for marginal/stomal ulcer and anastomotic stricture, which may need gastroscopy and dilatation. Bleeding or chronic non healing gastric ulcers may need revision surgery.   There is a risk for internal hernia and small bowel obstruction. This require an emergency operation.
Endoscopy procedures	Gastroscopy and ERCP can be performed with ease.	The remnant stomach can’t be screened with a gastroscopy.   ERCP is extremely difficult to perform and needs specialized double balloon enteroscoopy.   ERCP may not be possible in some patients.	The remnant stomach can’t be screened with a gastroscopy.   ERCP is extremely difficult to perform and needs specialized double balloon enteroscoopy.   ERCP may not be possible in some patients.
Pregnancy concerns	Pregnancy is generally safe and have minimal nutritional risk.	With morning sickness or inadequate dietary intake, there is a risk for vitamin deficiencies (especially folate) and risk for congenital malformation.   If bowel obstruction develops, it is not safe to order x-rays or perform surgery without adding risk to the pregnancy.	With morning sickness or inadequate dietary intake, there is a risk for vitamin deficiencies (especially folate) and risk for congenital malformation.   If bowel obstruction develops, it is not safe to order x-rays or perform surgery without adding risk to the pregnancy.
Specific surgical complication	Staple line leak and bleeding.	Anastomotic leak, marginal ulcer/stricture, bile reflux, adhesive small bowel obstruction.	Anastomotic leaks, marginal ulcer/stricture, internal hernia, small bowel obstruction.
Absolute or relative contraindications	Large hiatus hernia, acid reflux and Barrett’s oesophagus.	Inflammatory bowel disease, patients on NSAIDS, anti coagulation or immunosuppressants.   Previous major abdominal/pelvic surgery and adhesions.   Patients living in remote/rural areas with lack of medical services to treat surgical complications.	Inflammatory bowel disease, patients on NSAIDS, anti coagulation or immunosuppressants.   Previous major abdominal/pelvic surgery and adhesions.   Patients living in remote/rural areas with lack of medical services to treat surgical complications.

 

 

 

 

Physiology differences between the sleeve and bypass

We have to stress to the readers that the mechanisms of bariatric surgery are still not entirely clear.

 

In the past there have been a lot of studies on the hunger and satiety hormones, such as ghrelin and other incretins. Sometimes these studies create more confusion than clarity. In the future no doubt more scientific research and more information will be available to improve our understanding of obesity and metabolic problems.

 

Patients may choose gastric bypass surgery over the sleeve because of the superior weight loss results and the clinical improvements in T2DM but we do not understand the entire long term physiological consequences of this procedure.

 

The main anatomical difference between the sleeve and gastric bypass is the exclusion/bypass of the duodenum and proximal jejunum.

• This may have a weight independent anti diabetes effect which leads to remission of insulin resistance and T2DM (proximal or hindgut hypothesis). We do not understand this area very well.

 

 

• Nutrient exposure in the distal small intestine and changes in the immunological signaling pathways probably plays a significant role in metabolic syndrome as well. Whether this is due to weight loss (independent of the choice of weight loss surgery) or due to anatomical changes (dependent on choosing a gastric bypass procedure) we do not know for sure at this stage.

 

 

 

Definition of weight loss success after any bariatric surgery

The ideal weight for everyone following the Caucasian standard is to have a BMI 20-25. The world’s population in the last century rarely have morbid obesity issues.

This is obviously not the case any more in the 21^st century.

 

With the introduction of bariatric surgery, there is also a need to define what constitutes successful weight loss surgery outcomes.

• Around 1982, surgeons began describing weight loss surgery as achieving >50% excess weight loss (EWL) and this has been the standard to which we measure the success of bariatric surgery ever since.
• More recently the definition of weight loss success after surgery include >20% (total body weight loss) TWL. This is easier to calculate and TWL getting used more often in modern day scientific research.

 

In contrast the definition for success using medical pharmacology treatments (without bariatric surgery) is >5% TWL.

• Fortunately reduction in medical co-morbidities can be seen after 5-10% TWL.

 

Some researchers have noted that:

• Weight loss surgery provides 4 times the weight loss in the long term
• Overall the successful long term weight loss (>20% TWL) is expected in 70% of patients

 

 

The definition of weight regain after bariatric surgery however is not clear at this stage.

There has been several suggestion, which include:

• BMI >35 after initial success of BMI <35 after the initial surgery
• EWL <50% after initial success of >50% EWL after the initial surgery
• Weight regain >25% EWL from the lowest weight (nadir)
• Weight regain >10% from the lowest weight (nadir)
• Not able to maintain >20% TWL at all

 

 

Less successful outcome (<20% TWL) is observed in:

• Gastric band surgery
• Lower pre-op BMI
• Patients with pre-op T2DM and HPT
• Age over 40 years
• Male gender
• Substance abuse (alcohol)
• Medical causes of weight regain

 

 

 

 

Weight loss pre-operatively

From a technical point of view, bariatric surgery will not be safe or possible without adequate reduction in body weight, visceral adiposity and most importantly the size of the fatty liver.

 

Ideally patients are advised to lose >10% of their body weight or >3kg of body fat before elective bariatric surgery. This can be achieved using the very low calorie or energy diet (VLCD or VLED) and recently also the introduction of a very low calorie ketogenic diet (VLCKD).

• The low carbohydrate diet will reduce the glycogen storage in the liver.
• These diets also induce ketosis, which helps to suppress hunger.

 

 

Low calorie diet (LCD) is usually 800 – 1 200kcal per day, with >100g carbohydrate, 1g/kg protein a day and fat <30%.

 

Very low calorie diet (500 – 800 kcal/day, with >50g carbohydrate, 1.5g/kg protein (usually 65-70g protein/day) and <30% fat.

 

The Formulite, a brand of VLED has a higher content of protein, lower amount of carbohydrate and sugar. It also has added fiber, digestive enzyme and probiotics.

• This was introduced to improve patient tolerance due to the unwanted side effects of VLCD, which mainly include bloating, flatulence, constipation or diarrhea.
• There is probably no superior weight loss result between this and other brands of VLCD in the short pre-op period

 

 

Some dietician may also recommend omega 3 poly unsaturated fatty acid supplements together with VLCD in the pre-op period.

• This may be beneficial for patients with known non-alcoholic fatty liver disease (NAFLD).

 

 

 

 

 

 

Weight loss results after laparoscopic sleeve gastrectomy

 

The LSG produces weight loss results and improvements in T2DM comparable to the RYGBP in the medium term.

• The greatest benefit in having the LSG is the safety profile and the versatility of the procedure (option for revision in the future), especially for the young female patients in their reproductive age group, who does not have T2DM or cardiac disease.

 

Weight loss and resolution rate is better with the gastric bypass but there is probably no statistical difference between these two procedures in the 2 to 3 years follow up after the initial procedure.

 

In the long term, weight regain is higher with the sleeve than the gastric bypass, 3 to 5 years or more after the initial procedure.

 

 

It is estimated that nearly 15 – 30% of patients require revision surgery after an initial LSG for inadequate weight loss or weight regain.

• One study published that weight regain is estimated to occur in 5.7 % (after 2 years) to 75% (after 6 years).
• Obviously the figures depends on which definition of weight regain is used (as described above)

 

Weight regain after a LSG may be associated with:

• A larger sleeve remnant or large/undissected posterior fundic pouch
• Patients in the older age group
• Patients who achieve a lower maximum weight loss in the first year
• Poor eating habits or lack of positive lifestyle change after surgery
• Early or multiple pregnancies after the initial surgery

 

We need to emphasize that readers need to be cautious when reading any surgical literature and not apply everything they read to their individual case.

 

Weight loss success, failure or regain is really the interaction of a combination of factors:

• Technical factors (large sleeve remnant, sleeve dilatation)
• Physiological factors (regulation of gut hormones)
• Medical factors (poor metabolism , medical conditions, medication use, etc)
• Psychological factors (nutritional behaviour, maladaptive/binge eating, loss of control eating habits)

 

 

Weight regain after bariatric surgery

 

Weight regain will occur after any bariatric surgery with time.

Weight regain may be associated with the return of medical co-morbidities (hypertension, T2DM) and reduced health related quality of life.

 

It is estimated that patient will regain 5-10% of their total weight loss (TWL) within the first decade after bariatric surgery.

 

The percentage of patients who develop weight regain after a sleeve gastrectomy and RYGBP may occur up to 76-87% or more.

 

Specifically with regards to the RYGBP:

• The Swedish Obese Subject Study (SOSS) showed that after RYGBP, there is a regain of 10% of the TWL
• The Longitudinal Assessment of Bariatric Surgery (LABS) showed a regain of 7% TWL (7 years after RYGBP)
• Another study showed a regain of 12% TWL 12 years after RYGBP

 

 

 

Issues with polycystic ovarian syndrome (PCOS)

 

PCOS describes a combination of symptoms, which include:

• Obesity (>2/3 young women with PCOS also have obesity)
• Insulin resistance
• Hyperandrogenism (biochemical and clinical, such as hirsutism)
• Poly cystic ovaries
• Ovulatory dysfunction and subfertility
• There is an increased LH:FSH ratio (high LH leads to increase androgen production and low FSH impair ovarian follicular development)
• Increased oestrogen levels (may or may not be related to increased risk for developing breast and endometrial cancers)

 

With successful weight loss, there is a chance for restoration of menstrual patterns and ovulatory cycles.

 

Young female patients who are concerned about falling pregnant soon after weight loss surgery will need to consult their general practitioners or gynaecologist.

• Some patients are recommended to commence contraception prior to bariatric surgery.
• Patients are advised against falling pregnant in the 12 to 18 months after bariatric surgery.

 

 

Issues regarding pregnancy

 

Majority of patients considered for bariatric surgery in Australia are females in the younger reproductive age group.

• They face the choice of having weight loss surgery before pregnancy (for subfertility issues).
• Or after they have finished their family (to prevent weight regain issues).

 

One of the indication for weight loss surgery is PCOS and subfertility. After many failed attempts, such as IVF treatments, some patients may be referred by their gynaecologist for bariatric surgery.

 

Specifically weight loss:

• Helps to reduce the risk for developing gestational diabetes, hypertension in pregnancy, fetal macrosomia (or the opposite small for gestational age), pre term delivery (or admission to the neonatal intensive care unit).
• Reduce the elective/emergency Caesarean delivery rate and post-partum haemorrhage.

 

These two factors are the common reason for younger women seeking bariatric surgery. However, most surgeons recommend that patients post pone getting pregnant for 12 to 24 months after bariatric surgery:

• To allow adequate time to lose weight and time for resolution of medical co-morbidities associated with obesity.
• Also to reduce the risk of developing micronutrient deficiencies during pregnancy.

 

Patients need to discuss with their GP or gynaecologist regarding contraception after weight loss surgery.

• With the enlarging uterus, the intra-abdominal pressure is increased and the intestine and other abdominal organs are displaced upwards. The risk of small bowel obstruction may increase, especially after previous intestinal surgery or gastric bypass.
• It is much safer for patients intending to get pregnant in the future to have a sleeve than a bypass. The RYGBP, OAGB, SADI or BPD may be associated nutritional deficiency during pregnancy. This may lead to small for gestation age fetus and premature births.

 

Patients who are pregnant must have supplements regardless of whether they had a sleeve gastrectomy or a bypass. These include:

• Folic acid 0.4 to 1mg daily up to 12 weeks of gestation (to prevent neural tube defects) (5mg daily if there has been a history of NTD in the past)
• Iron supplements 50-80mg per day
• Vitamin B12 1mg per week
• Zinc 10mg per day
• Copper 1mg per day
• Vitamin A less than 5 000 IU per day
• Protein intake should be more than 60g a day

 

Obviously these patients needs to be screened for gestational diabetes.

 

 

Weigh gain may occur after pregnancy or breast feeding.

• If there are no medical risk factors, some patients may elect to have weight loss surgery after they have finished their family in order to reduce the risk of weight regain.

 

 

 

Issues with medications and absorption

 

Patients will need close monitoring for some of their medical conditions and have their medications adjusted by the GP before and after weight loss surgery. Especially pertaining to hypertensive, diabetic, thyroid medications, antidepressants and various other tablets.

 

Patients are advised to avoid cigarette and non-steroidal anti-inflammatory drugs to reduce the risk of gastric ulcers, bleeding and perforation.

 

 

Issues with gallstones (GS)

 

Studies reported asymptomatic or symptomatic gall stones developed in 26 to 30% of patients after a sleeve gastrectomy in the first year.

Symptomatic gallstones occur at a higher rate after gastric bypass, some studies reported GS in up to 29% of these patients. The risk increases because of rapid weight loss in a shorter period of time.

 

There is no consensus for the role of medications (ursodeoxycholic acid) to prevent gallstone formation or the role for prophylactic cholecystectomy.

• Ursodeoxycholic acid is a secondary bile acid that inhibits cholesterol secretion in the bile, which helps to reduce cholesterol stone formation.
• Some patients will need to take this medication 500mg daily for more than 6 months in order to see benefits in the reduction rate for cholecystectomy (in the first 1 to 3 years after bariatric surgery).

 

 

 

Issues with gastro-oesophageal acid reflux (GERD)

 

It is estimated that de novo gastro-oesophageal reflux may be present in over half the patients before bariatric surgery.

 

After a sleeve gastrectomy the reflux symptoms may be resolved with successful weight loss in maybe up to 60% of patients, (it may remain unchanged or becomes worse).

 

In contrast another study reported:

• That 70% of patients who had GERD pre-operatively will continue to have GERD after surgery.
• Incidence of new onset of GERD is estimated to occur in up to 35% of patients

 

Intra thoracic migration of the remnant tubularized stomach up into the chest is now being recognized to occur after a sleeve gastrectomy. The shortened oesophagus may also increase the risk of the upward gastric migration.

• This may cause refractory reflux as well as difficulty swallowing (dysphagia) and chest pain (odynophagia) during meals.
• Often this will require a surgical correction to repair the hiatus hernia.

 

Most surgeons do recommend RYGBP for patients with severe reflux. But note symptomatic reflux may persist even after the RYGBP, there is no guarantee that the RYGBP will eliminate all the heartburn symptoms.

• Before patients decide to have a RYGBP, it is encouraged that they do more research into the long term side effects and complications of surgery. Please read the blog on Roux Y gastric bypass.

 

 

Assessments for reflux

 

Reflux is diagnosed by patient’s self reporting or via a patient based questionnaire.

 

The Montreal definition (2006) (this is patient symptom based not endoscopic diagnosis) states that GERD is a disease associated with troublesome symptoms and complications due to reflux of stomach contents up the oesophagus. There are classified as oesopahgeal or extra-oesophageal symptoms, which may include laryngitis, cough, asthma and dental problems related to acid reflux.

 

GERD is often an empirical diagnosis based on the doctor’s assessment and the patient’s response to a trial of PPI medications.

• Few patients are referred to have a screening gastroscopy (to diagnose the severity of reflux, such as the LA classification for erosive oesophagitis) or to check for complications (such as Barrett’s oeosphagus).
• Even less frequenty patients are referred for physiological testing, such as a high resolution oesophageal manometry study (HRM) (using the Chicago criteria, a classification system for oesophageal dysmotility)
• Or ambulatory 24 hour multi-channel intraluminal impedance pH study (MII-pH).

 

The Los Angeles (2005) classification (A to D) is an endoscopic diagnosis and grading system for the severity of erosive oesophagitis, based on the length of the mucosal breaks, the extend or the confluence of the erosions.

 

The Rome 4 criteria were more strict to define the heartburn phenotypes. The consensus group also recommended an oesophageal biopsy at the same time to rule out oesinophillic oesohagitis.

• This is to help distinguish between non erosive reflux disease (NERD) from functional heartburn and reflux hypersensitivity.

 

The Lyon consensus group evaluated GERD diagnostic tests and categorize these diagnostic tests as being adequate (to diagnose/refute GERD) or being inadequate (where more investigations are needed, as mentioned above).

 

Reasons to consider a RYGBP

• The rate of new onset of reflux is much higher after a sleeve gastrectomy compare to a gastric bypass. The possible explanation for this may include the destruction of the angle of His, deceased gastric compliance and increased intraluminal gastric pressure causing secondary regurgitation and reflux.

 

• Similarly GERD symptoms has been reported to improve by 90% after RYGBP. Reflux oesophagitis may decrease from 45 to 20%. However there are patients with persistent reflux symptoms after RYGBP, the reason for this is uncertain.

 

 

 

Gastroscopy checks after a sleeve gastrectomy

Investigations for Barrett’s oesophagus

 

It is well published that the sleeve gastrectomy is highly efficient in achieving good medium/long term significant weight loss and resolution of medical co-morbidities.

 

LSG reduces gastric compliance and increased intra gastric pressure, which may be good for restriction and satiation but it may also cause food regurgitation or acid reflux up the oesophagus.

 

Consequently a significant number of sleeved patients do suffer from acid or alkaline/bile reflux.

• Majority of these symptoms may be mild but a few develop oesophagitis and Barrett’s oesophagus (maybe in up to 6% of patients after a sleeve).
• Fortunately there had been no reports that sleeve gastrectomy result in increased risk of oeosphageal cancers at this stage.
  • One study reported that the annual oesopahgeal adenocarcinoma or cancer risk for a short segment (<3cm) Barrett’s eosophagus was 0.03% and for a long segment (>3cm or 4 -10cm) Barrett’s oesophagus was 0.22%.

 

 

With regards to heartburn or dysphagia (difficulty swallowing)

• A post op Barium swallow test or gastroscopy is recommended.
• A gastroscopy is necessary to search for erosive/reflux oesophagitis, which is described using the Los Angeles classification.
  • The gastroscopy is also important to diagnose or exclude a hiatus hernia, peptic stricture, Barrett’s oesophgus, peptic ulcer disease and duodeno-gastric bile reflux or chemical gastritis.

 

Barrett’s oesophagus needs to be confirmed on endoscopy and biopsy.

• The Seattle protocol described 4 quadrant biopsies every 1-2cm along the columnar lined oesophagus starting from the gastro-oesophageal junction (at the top of the gastric rugae folds).
• Histology confirmation with both specialized intestinal metaplasia and Goblet’s cells. Obviously it is important to rule out dysplastic or malignant changes on histology.

 

Some gastroscopes have magnifying views and narrow band imaging, a special optical image enhancing technology to inspect the vascular and mucosal pattern to help target the biopsies to the area of concern (areas of neovascularization) to improve the detection rate for Barrett’s metaplasia and dysplasia..

 

Gastroscopy can describe the extend and subsequent regression of the Barrett’s oesophagus using the Prague classification.

• Obviously patients will need life long surveillance once Barrett’s oesophagus is diagnosed, the clinical guidelines has been published by the Gastroenterological Society of Australia (GESA).
• Patients are usually referred to a gastroenterologist who specializes in this area for long term screening and surveillance.

 

Other investigations are available to diagnose acid reflux if the Barium swallow test or gastroscopy is inconclusive, such as a high resolution manometry or 24 hour pH study. However this is uncommonly done at the present time.

 

• There are various endoscopic treatment options for Barrett’s oesopahgus with dysplasia. The more common procedures include radio-frequency ablation using the Halo technology (HALO RFA) with a reported 98% success rate and 92% of patients remains disease free after 5 years of follow up.
• Other endoscopic treatments include argon plasma treatment (APC) or endoscopic mucosal or submucosal resection (EMR or ESD).

Once again it is stressed that all these procedures should be done by a gastroenterologist with specialized interest in screening and treating Barrett’s oesophagus.

 

 

 

 

RYGBP is only one option for treating reflux or Barrett’s oesophagus after a sleeve gastrectomy

 

Please read the section on sleeve or gastric bypass regarding issues with reflux after a sleeve gastrectomy.

 

RYGBP is very effective in controlling heartburn symptoms in a majority of patients. However it is emphasized that the reflux symptoms may persist (partial resolution) or recur many years later.

• Medications such as antacids (Gaviscon, Mylanta, etc) and PPI medications may need to be continued in the long term.

 

 

RYGBP is an effective surgical treatment for sleeved patients with severe heartburn symptoms or those who had developed complications, such as erosive oesophagitis or Barrett’s oesophagus.

• Barrett’s remission rates of 50 to 80% has been reported.
• Some patients has been reported to be free of dysplasia after RYGBP.

 

In other words RYGBP does not always achieve complete resolution of the reflux symptoms or guarantee resolution of Barrett’s oesophagus.

 

 

 

 

This blog provides free general information for anyone who is seeking to understand more about post op diarrhoea and dumping syndrome, not intended as a medical consult. Please seek proper medical advice for individual assessment and management.

 

The crucial learning points are:

• Loose stools after surgery may be due to many reasons, which may include infectious gastro-enteritis or colitis, inflammatory bowel disease, food poisoning, food intolerance (Coeliac’s disease or lactose intolerance), bacterial overgrowth, diabetic autonomic neuropathy and many other reasons
• How to recognize and potentially avoid dumping and post op hypoglycaemia related to bariatric surgery
• It is rare to need to reverse the bypass operation for severe dumping syndrome or malnutrition

 

 

 

Diarrhoea

 After gastric bypass, it is expected that some patients will have diarrhoea.

This is not the same as dumping or hypoglycaemia.

 

The definition of chronic diarrhoea is more than 3 loose stools a day, >200g/day lasting for over 4 weeks.

 

Chronic diarrhoea after gastric bypass will negatively affect quality of life and social functions.

• For example patients who operate heavy machineries or truck drivers may not be able to continue with their job.

 

Diarrhoea, dumping and pancreatic insufficiency may be reduced by avoiding an aggressive malabsorptive procedure.

• For example a proximal gastric bypass is better than a long biliary limb or distal gastric bypass or a SADI-S type operation.

 

Diarrhoea can also be a result of intestinal bacteria overgrowth and pancreatic enzyme insufficiency. Obviously differential diagnosis needs to be excluded as well, such as infectious gastro-enteritis/colitis, pseudomembranous colitis (Clostridium difficile) or inflammatory bowel disease.

 

Investigations that is usually ordered include:

• Breath test for lactulose (which may indicate bacterial overgrowth)
• Breath test 13C mixed triglyceride (which may indicate pancreatic insufficiency)
• Stool culture for an infective cause
• 3 days stool samples can be sent for faecal fat and faecal elastase 1 level (which may indicate pancreatic exocrine insufficiency)
• Secretin enhanced MRCP (for pancreatic insufficiency)

 

 

 

Steatorrhoea

Steatorrhoea is loss of undigested dietary fats in the stools, with a faecal fat content >7g/day.

This is not the same as osmotic diarrhoea or early dumping.

 

The longer biliary limb (more than 50cm bilio-pancreatic limb) used in gastric bypass may result in:

• A shorter the common channel, with a higher the risk for fat malabsorption or steatorrhoea
• There is delay of delivery of pancreatic and other digestive enzymes to the alimentary limb
• The long bilio-pancreatic limb may also result in bacteria overgrowth, which may deconjugate the bile salts and impede the digestion of dietary fats
• Free bile salts may be toxic to enterocytes and worsen the steatorrhoea

 

 

 

Small intestinal bacterial overgrowth

This is caused by overgrowth of bacteria in the lumen of the small intestine after a bypass operation. A lactose breath test may help to diagnose this condition.

 

The symptoms include nausea, vomiting, bloating, increase flatulence, abdominal pain and diarrhoea.

 

Symptoms may improve with antibiotic (ciprofloxacin, doxycycline, amoxicillin or metronidazole) treatment, which is usually prescribed for 1 month.

 

However antibiotic use may be associated with Clostridium difficile infection (Pseudomembranous colitis) and makes the diarrhoea worse.

• This is diagnosed with PCR test from the stool cultures.

 

 

 

Diabetic patients with autonomic neuropathy

Up to 40% of diabetic patients may have autonomic neuropathy and enteropathy. This may result in worsening watery diarrhoea after gastric bypass surgery.

 

Anti-motility drugs such as loperamide may help.

 

 

 

Food intolerance

Some patients may have undiagnosed food intolerance, such as gluten insensitivity (Coeliac’s disease) or lactose intolerance.

 

This can be diagnosed with blood test or gastroscopy with duodenal biopsies.

 

 

 

Vitamin B3 (Niacin) deficiency

Niacin deficiency may result in diarrhoea, dermatitis and dementia, sometimes known as pellagra.

 

Treatment is to increase oral niacin tablets.

 

 

 

Overflow diarrhea

Some patients may have chronic constipation or Irritable Bowel Syndrome. Diarrhoea may be the result of laxatives and artificial sweeteners.

 

 

 

 

Dumping and hypoglycaemia

Dumping and post prandial hypolgycaemia may affect up to 10% or more of patients after a gastric bypass operation. Some studies even report over 40% of patients developing dumping after a gastric bypass operation.

 

There are 2 types of dumping syndrome.

 

Early dumping usually occurs within minutes after eating a meal (usually within 15 minutes and may occur up to 1 hour later).

• This is often a result of the rapid entry of hyper osmolar food into the small intestine, resulting in a fluid shift into the lumen of the small bowel (higher osmotic force in the lumen, fluid exiting the intra vascular volume, drop in intravascular volume sensed by the arterial baroreceptors, subsequent activation of sympathetic nervous system and leads to an increase in noradrenalin)
• Gastro-intestinal hormones (VIP, GIP, insulin and glucagon) are released and also contribute to the early dumping.
• GLP-1 may also activate the sympathetic nervous system, this hormone plays a role in causing early and late dumping (please read the paragraph below)
• Symptoms of early dumping may include palpitations (fast heart rate), increased perspiration (increase sweatiness), feeling faint, fatigue, abdominal cramps, nausea and watery diarrhoea
• Patients are advised to avoid foods that may cause early dumping (eg. avoiding the high osmotic foods, avoid the high GI index foods and limiting carb intake to <50g a day).

 

Late dumping or post prandial hypoglycaemia usually occurs 1 to 4 hours after a meal.

• After a gastric or duodenal bypass, there is a faster glucose re-absorption and faster release of glucagon-like peptide 1 (GLP-1) from the distal ileum. This results in elevated post prandial insulin. With faster insulin release and improved insulin sensitivity, this will lead to reactive hypoglycaemia.
• Many hypoglycaemia episodes may be asymptomatic.
• Patients are advised to avoid foods that cause late dumping (eg. avoiding the high GI index foods, limiting carb intake to <50g a day).
• Other treatment options include alpha glucosidase inhibitor Acarbose (which slows down carbohydrate digestion and absorption in the small intestine), calcium channel antagonist (inhibit insulin secretion from pancreatic Beta cells), GLP-1 analogs and somatostatin analogs (both helps to stabilize blood insulin levels)
• Diazoxide may be another option

 

 

 

Mechanism of dumping syndrome

To re-iterate, although the early and late dumping syndrome symptoms may be very similar, the onset of action and mechanisms are different.

 

Early dumping may be due to a combination of:

• Rapid transit of hyper osmolar load to the small bowel, excess fluid loss into the small bowel lumen, relative hypotension and sympathetic nervous system activation (without hypoglycaemia)

 

Late dumping or post bariatric hypoglycaemia may be due to a combination of:

• Rapid transit of food to the distal small bowel, release of GLP-1, excess insulin release and subsequent hypoglycaemia
• Attenuated glucagon response
• Reduced insulin clearance
• Impaired Beta cell secretory suppression even in the presence of hypolgycaemia

 

The specific diagnostic criteria for post bariatric hypoglycaemia include:

• The presence of neuroglycopenic symptoms with a post prandial blood glucose level ❤ mmol/L
• Occurrence >6 months after bariatric surgery
• In the absence of fasting hypoglycaemia

 

 

 

 

 

Summary

 

Certainly diarrhoea and associated gut symptoms are expected for all patients who had a sleeve gastrectomy or gastric bypass.

 

For mild symptoms this may be controlled with simple dietary alterations.

 

Severe symptoms associated with malnutrition are particularly difficult to treat and a few patients may even end up having to reverse the primary bariatric procedure.

 

Hence it is important to go through the list of possible causes and do adequate investigations to search for the above.

 

This blog provides free general information for anyone who is seeking to understand more about obstructive sleep apnoea, not intended as a medical consult. Please seek proper medical advice for individual assessment and management.

 

 

The crucial learning points are:

• Obstructive sleep apnoea (OSA) is common the obese patient cohort and is often undiagnosed.
• Untreated OSA is associated with poor sleep patterns and difficulties in losing weight.
• Severe OSA increases the risk of surgery.

 

 

This section won’t discuss cigarette smoking and its respiratory issues.

• Obviously all patients need to stop cigarette smoking (also no vaping) for at least several months before bariatric surgery and should never recommence smoking after.

 

 

 

 

Obstructive sleep apnoea (OSA)

 

OSA is a chronic disorder characterized by repetitive obstruction of the upper airways during sleep. This leads to fragmented sleep and low oxygen levels in the blood (hypoxemic episodes).

 

Apnoea hypopnoea index (AHI) is the number of apnoea or hypopneoea events (>10 seconds in duration) recorded during sleep in one hour. In a simplistic term:

• AHI < 5 is normal
• AHI 5-14 is mild OSA
• AHI 15-29 is moderate OSA
• AHI > 30 is severe OSA

 

A continuous positive airway pressure (CPAP) machine at home is usually recommended for moderate and severe OSA.

 

 

70-80% of patients with morbid obesity is estimated to have OSA.

Surgery increases the risk of hypoxemia and the post op complications are increased in patients with OSA.

After surgery patients will need continuous positive airway pressure (CPAP) therapy starting straight away from post op day 1.

 

Successful weight loss after bariatric surgery reports significant improvements in AHI, hence improvements in OSA.

 

 

 

Subjective screening tools: STOP-BANG and ESS questionnaire

Many different surveys are available, these are the more common ones

 

Patients can be screened using the STOP-BANG questionnaire, which is a simple yes or no answer to the following criteria:

• Snoring loudly
• Tired or falling asleep during the daytime, during driving or when talking to other people
• Observed to have stop breathing during sleep
• Pressure – high blood pressure
• Body Mass Index
• Age over 50 years
• Neck circumference (male > 43cm, females > 41cm)
• Gender (Male)

 

If the response is yes to 4 criteria or more, it is likely that the patients have OSA.

 

 

 

The Epworth Sleepiness Scale (ESS) for adults (1997) is a questionnaire asking the patient to score between 0 to 3 for the following scenarios

0 = would never doze

1 = slight chance of dozing

2 = moderate chance of dozing

3 = high chance of dozing

 

In situations such as:

• Sitting and reading
• Watching tv
• Sitting inactive in a public space (theatre, meeting)
• As a passenger in a car (for an hour without a break)
• Lying down to rest in the afternoon
• Sitting or talking to someone
• Sitting quietly after lunch (without alcohol)
• In a car (stopped for a few minutes in the traffic)

 

ESS scores:

• 0-5 is normal daytime sleepiness
• 6-10 is upper limit of daytime sleepiness
• 11-12 is mild excessive daytime sleepiness
• 13-15 is moderate excessive daytime sleepiness
• 16-24 is severe excessive daytime sleepiness

 

Narcolepsy patients often has an ESS >13

 

 

 

OSA and bariatric surgery patients

 

However it is also noted that a lot of younger morbidly obese patients who come for weight loss surgery do have OSA but don’t have the symptoms above.

 

Obesity is a significant risk factor for OSA.

• Untreated OSA may be associated with increased cardiovascular morbidity and mortality.
• For now there is no mandatory routine pre-op sleep studies for patient coming for bariatric surgery.

 

However the high risk patients (criteria above) are recommended to have a sleep study and a respiratory physician review as well as having a pre-op Echocardiogram (to look for cardiomyopathy and pulmonary hypertension).

 

 

Patients with severe cardiomyopathy, pulmonary hypertension or right heart failure may be rejected fir elective weight loss surgery because of the prohibitive risk.