This blog provides free general information for anyone who is seeking to understand more about Roux Y gastric bypass, not intended as a medical consult. Please seek proper medical advice for individual assessment and management.
The crucial learning points are:
- The reason to perform Roux Y gastric bypass
- How the RYGBP works (the alteration in gut hormones)
- The long term complications of RYGBP
- The nutritional consequences after RYGBP in the long term
- The comparison between sleeve gastrectomy and RYGBP
The need for Roux Y gastric bypass
The laparoscopic sleeve gastrectomy and Roux Y gastric bypass (RYGBP) are two commonly performed bariatric operations with a great success rate. This blog is dedicated to the latter.
Bariatric/metabolic surgery is considered the most effective treatment for obesity and its associated medical co-morbidities (for patients with Class 2 or 3 obesity), to improve the quality of life and prevent premature metabolic or cardio-vascular complications.
For decades RYGBP has been the gold standard of bariatric surgery and is performed in large volumes across North America and other parts of the world. For patients with morbid obesity and multiple medical problems, RYGBP is a good option because unlike the gastric band, it does not rely on restriction of food intake alone. It has beneficial hormonal changes to assist in satiation and more effective control of Type 2 diabetes mellitus. RYGBP is also a preferred revisional bariatric procedure for many bariatric surgeons because of its potential combined restriction, gut hormonal changes and mal-absorptive effects.
Few surgeons will debate the superiority of RYGBP as a bariatric procedure, especially for the morbidly obese with type 2 diabetes. But compared to the sleeve gastrectomy, RYGBP is a more technically difficult operation with longer operating time and higher complication rate, both in the immediate and long term. Lifelong blood tests and surveillance for nutritional problems are necessary.
The physiology or hormonal effects after RYGBP
It is important to appreciate that there are various alteration to the gut hormones after RYGBP. The standard (100cm Roux limb) gastric bypass operation creates a small gastric pouch (the restriction effect), allows food is diverted away from the proximal small bowel and rapid delivery to the distal small bowel (the gut hormone effect to the entero-insular axis). The long limb or distal gastric bypass (>150cm Roux limb) allows food is delivered mostly undigested to the distal small bowel (the malabsorption effect).
The mechanisms of how bariatric/metabolic surgery actually work and its therapeutic effect on Type 2 diabetes mellitus is still under investigation. At this stage there is still a lot of research into this vital topic and no doubt more information will emerge in the near future.
What we do suspect at this stage is that obese patients have a relative resistance to various hormones (such as leptin, insulin and others?). It has also been observed that obese patients have a blunted response to a postprandial (after meal) rise in PYY and GLP-1 hormones, which may result in impaired satiety response and consequently patients can continue to have large meals without feeling full.
After RYGBP as a result of rapid nutrient delivery to the distal small bowel, there is earlier release of hindgut hormones, postprandial appetite centre (in the brain) response to PYY and GLP-1 is partially restored, resulting in fullness sensation earlier during meal times and affecting behaviour change. The clinical effect is that post op patients stop eating when feeling full earlier after a smaller meal portion, thus reducing caloric intake and eventually weight loss.
Similar to sleeve gastrectomy, ghrelin hormone has been observed to be lower after RYGBP (although at this stage ghrelin reduction have only been proven to occur in the short term and there are still inconclusive results about permanent reduction or any important role for ghrelin in the long term). Reduction of ghrelin results in the decrease in hunger sensation, as a result reduced caloric intake and weight loss. Researchers have found that high levels of ghrelin also contributes to the insulin resistant state, hence it is deduced that reduction of ghrelin reduces tissue (liver) insulin resistance, restores insulin transport and normal liver glucose homeostasis, an important step in amelioration of Type 2 diabetes.
With regards to obesity and Type 2 diabetes, the benefits of RYGBP (rather than just restriction from a small gastric pouch) are postulated to derive from changes to a combination of hormones:
The reduction in orexigenic hormone (ghrelin)
- Reduction in ghrelin results in immediate diminution of appetite, improved postprandial insulin response and lower fasting glucose levels, often before any significant weight loss has occurred.
The increase in satiation and incretin hormone (PYY and GLP-1) with effect on the entero-insular axis
- The satiation sensation achieved after meal is important for the patient to feel satisfied after a meal and stop eating, creating a negative feedback loop termed “ileal brake”. If the sensation is achieved earlier after small meals, caloric intake can be reduced.
- GLP-1 is also a powerful incretin hormone that stimulates pancreas insulin release. This leads to a more rapid and greater postprandial insulin response after meals.
The hindgut hormone theory is believed to be significant because in the initial weight loss phase there is insufficient body weight or fat loss to account for the early improvement in diabetic state. More importantly these hormones assist in maintaining satiation, provide durable long-term weight loss and the potential for partial or complete resolution of Type 2 diabetes.
In contrast non-operative management (diet, exercise or intensive medical therapy without bariatric/metabolic surgery) have been proven to fail as a therapeutic treatment of morbid obesity and Type 2 diabetes. The fluctuating body weight (yo-yo weight) is a testament to the relative ineffectual weight loss achieved from fasting/dieting or restriction alone without a more permanent gut hormone change.
RYGBP for obesity and gastro-oesophageal reflux
Gastro-oesophageal reflux is often associated with morbid obesity, the consequence of a hiatus hernia, raised intra-abdominal pressure as well as other intrinsic factors (reduced lower oesophageal sphincter tone, delayed gastric emptying, impaired oesophageal transit/clearance times and increased episodes of transient relaxation of the lower oesophageal sphincter).
It is well known that laparoscopic anti-reflux surgery (hiatal hernia repair and fundoplication) generally fails in patients with a BMI>35. Many experts nowadays are recommending bariatric surgery as a treatment option for reflux in the obese population.
RYGBP is a very effective operation for morbid obesity, Type 2 diabetes, gastroparesis and refractory reflux all at the same time.
Laparoscopic sleeve gastrectomy for obesity and gastro-oesophageal reflux
There is definitely a risk that reflux may become worse after a sleeve gastrectomy, if a hiatus hernia is not repaired concomitantly at the time of the index bariatric procedure.
However in the absence of a hiatus hernia, there is also controversy regarding performing a sleeve gastrectomy in those with reflux disease because the operation is perceived to increase the gastric intra-luminal pressure. In turn this may lead to secondary regurgitation and reflux.
There are still conflicting reports on whether reflux will or will not improve after a sleeve gastrectomy. Proponents for sleeves report better reflux control after surgery due to the combination of weight loss, reduced intra abdominal pressure, reduced gastric acid production (from the longitudinal gastric resection) and improved gastric emptying as well as better eating habits after surgery (reduced volume eating), all of which reduces the risk for regurgitation.
There is less controversy in recommending RYGBP for the morbidly obese with complicated gastro-oesophageal reflux disease but it is important to note that RYGBP does not necessarily treat reflux entirely because reflux may be the result of many factors (as listed above). There are no arguments that the Roux Y gastric bypass is very effective for treatment of bile reflux.
Complications after Roux Y gastric bypass
The second half of this blog discusses some of the common complications after RYGBP, focusing mainly on the long-term issues.
In the immediate post op period, anastomotic leak and sepsis is the most feared complication associated with a mortality rate, which has been reported to be less than 1%.
In the longer term the concerns are marginal/stomal ulcers resulting in iron deficiency anaemia, stenosis (anastomotic stricture), internal hernia (resulting in abdominal pain and bowel obstruction), gastro-gastric fistula and weight re-gain. Some of the less common reported problems include persisting gastro-oesophageal reflux, dumping syndrome and reactive hypoglycaemia, with up to 9% re-operation rate reported in some series.
Gallstones after RYGBP
After bariatric surgery there is increased bile cholesterol saturation, increased secretion of mucin in the gall bladder and reduced gall bladder motility (which can be a consequence of vagal nerve disruption).
Ursodeoxy-cholic acid is sometimes used in the first 6months after the RYGBP to prevent bilairy lithiasis, to reduce cholesterol and mucin concentration, increase bile acid concentration, reduce bile salt saturation and enhance gall bladder emptying.
After weight loss stabilization (generally 2 years after RYGBP), there is a decrease in cholesterol mobilization from tissues and a reduction in rate of gall stone formation.
Dumping syndrome after RYGBP
Note that dumping syndrome and nutritional deficiencies can occur with laparoscopic sleeve gastrectomy as well but to a much lesser extent compared to RYGBP or the bilio-pancreatic diversion/duodenal switch.
Dumping syndrome is more common after RYGBP than the sleeve gastrectomy. It is reported to occur in up to 75% of patients after RYGBP but majority of the symptoms are mild and may persist in only 12% of patients after 2 years. The most common symptoms are post-prandial fatigue (feels tired after meals), need to lie down or maybe feeling faint after meals.
Early dumping syndrome tends to occur within 10-30 minutes after meals due to the rapid load of high osmolar contents into the small bowel. The symptoms are either gastrointestinal (abdominal pain, diarrhoea, borborygmi or loud noises, nausea, bloating) or vasomotor (fatigue, need to lie down after meals, facial flushing, palpitations, perspiration, tachycardia, hypotension, syncope). Early dumping symptoms may be prevented or reduced by avoiding high GI index foods.
Late dumping syndrome tends to occur 1-3 hours after meals due to insulin release after meals and reactive hypoglycaemia. The symptoms include perspiration, palpitation, fatigue, hunger, confusion, agitation, tremor and syncope. Late dumping may be reduced or ameliorated by reducing carbs (starch) contents in the diet or simply have a drink or lolly (for the hypoglycaemia).
It is noted that many patients may already have pre-existing gastro-intestinal symptoms before surgery and not all the symptoms they experience are due to dumping syndrome. And the majority of patients learn to regulate their dietary intake and eating behaviour in order to avoid dumping after RYGBP.
Weight re-gain after RYGBP
RYGBP is often the revision procedure of choice for many surgeons after a failed gastric band or inadequate result after a sleeve gastrectomy. However inadequate weight loss or failures have also been reported after a primary RYGBP.
Revisional surgery after RYGBP may be needed with the aim to either increase restriction or increase the malabsorptive component of the bypass.
- Some surgeons have questioned the value of more restriction because the RYGBP seldom succeed in changing the eating behaviour and the gastric pouch reduction is prone to fail again.
- Distalizing the bypass in the long term produces good weight loss results but also significantly increases the risk of nutritional complications (vitamin and trace mineral deficiencies, protein malnutrition and cachexia) and has severe metabolic consequences.
Nutritional consequences and complications after RYGBP
Pre-operatively it is routine to perform blood tests in order to screen for nutritional deficiencies, especially for iron, B12, folate, calcium and vitamin D that may have already been present. Some patients are also detected to have deficiencies of other fat soluble vitamins (A, E, K), vitamin B complex, zinc, copper, magnesium and selenium.
Routine use of multi-vitamin supplements is common after RYGBP but supplements alone may not be sufficient to prevent post op nutritional deficiency. The American Bariatric Society (ASMBS) recommends that vitamins and minerals supplements be commenced after gastric bypass surgery upon discharge from hospital at double the doses of conventional amount, as well as extra or complementary supplements when necessary.
Protein deficiency after gastric bypass is predicted to occur in up to 13% of patients (after 2 years) and up to 28% (after 10 years).
Protein malnutrition is more commonly seen with the distal or long limb gastric bypass (where the Roux limb is in excess of 150cm) whereas the standard Roux Y gastric bypass (has a 100cm Roux limb) is less likely to result in protein malabsorption, the incidence may be <5%.
Protein deficiency tends to occur 1-2 years after RYGBP but may develop earlier.
Deficiency is the result of reduced oral/dietary protein intake (as a result of the reduced gastric capacity, red meat intolerance, insufficient chewing) or rarely malabsoprtion (as a result of reduced secretion of digestive enzymes) in the long limb bypass.
Protein deficiency results in muscle weakness, hair loss and oedema (swelling).
The recommended daily protein intake is 1 to 1.5g/kg ideal body weight. After surgery the recommended protein supplement should contain a high component of branches amino acids (that is needed to prevent muscle tissue degradation), which remains stable in the stomach, is rapidly digested and is lactose free. A good supplement would be hydrolyzed whey protein that is commercially available.
Anaemia (iron, folate, vitamin B12)
Some reports state that anaemia may be present in 52% of patients (2 years after surgery) and up to 74% of patients (in the longer term) after RYGBP. Macro and micro nutrient deficiencies need to be properly diagnosed and managed early in order to prevent deterioration in health, adversely affecting quality of life and to prevent further complications. Iron deficiency anaemia is the most common followed by folate and vitamin B12.
Iron deficiency is the most common and may already be present before bariatric surgery.
- Post operatively iron deficiency is reported to occur in 6-52% of patients and may occur as early as 2 months after RYGBP.
- Younger women (in reproductive age group) have a higher risk of iron deficiency anaemia and this group represents up to 80% or more of bariatric surgery candidates.
- Daily supplemental dose of 36-65mg of elemental iron is recommended.
Blood test is performed to measure serum ferritin (which represents body iron storage), however it is important to note that ferritin is also an acute phase reactant. A drop in ferritin also reflects a reduced inflammation state, which is amongst the positive benefits of bariatric surgery and visceral fat loss.
- There is a rise in serum iron after surgery as a result of the drop in ferritin and the increase in bioavailability.
Folate absorption occurs mainly in the jejunum (but also occurs across the small bowel).
- Hence folate malaborption not considered the main reason for folate deficiency after RYGBP but rather it is due to lack of dietary folate intake or inadequate oral supplements.
- Folate deficiency occurs in 9-38% of patients and is particularly important for women who are pregnant (to have adequate folate replacement to prevent fetal neural tube defects).
- Daily folic acid supplemental replacement up to 1000 microgram is recommended.
Vitamin B12 (cobalamin) requires hydrochloric acid to aid digestion and intrinsic factor to aid absorption in the terminal ileum.
- Low intake of red meat after surgery often will result in reduced vitamin B12 and folic acid, as well as reduced iron, zinc and vitamin B1 (thiamine).
- After RYGBP there is reduced gastric hydrochloric acid and pepsinogen mixed into the food, this may compromise the digestion of protein or absorption of B12.
- Deficiency may occur in 26-70% of patients after RYGBP, a large range because B12 deficiencies often occur late (since the liver B12 storage usually last for more than 12 months).
- Supplemental B12 can be administered as oral or sublingual forms rather than intra muscular injections. Daily oral supplements need to be over 500-1000 micrograms because lower doses has poor absorption.
Other vitamin and trace mineral deficiencies
In contrast to B12, vitamin B1 (thiamine) deficiency is relatively uncommon except for those who develop persistent post op nausea and vomiting.
- The risk may be 1% in the first 6 months.
- For prevention 3mg daily oral supplement is recommended.
- Serious neurological consequences such as Wernicke’s encephalopathy and Korsakoff syndrome (which is difficult to reverse) have been described.
Calcium and vitamin D deficiency is very common and it is important to recognize and treat this condition early.
- After long limb or distal RYGBP calcium deficiency occurs in 10% of patients (after 2 years) and the incidence may be as high as 50-80% in the long term.
- Vitamin D deficiency has been measured in 84% of obese patients even before surgery and the risk for vitamin D deficiency (bone mineral loss and secondary hyperparathyroidism) after RYGBP is very real.
- It is recommended that post-menopausal women have up to 2000mg elemental calcium a day.
- Calcium citrate (has better absorption in a low or non acid environment than calcium carbonate) combined with up to 800-2000 IU cholecalciferol (vitamin D3) is recommended to prevent rapid bone loss in the early phase after RYGBP.
Vitamin A deficiency may occur in 11% of patients post op.
- This results in diminished night vision or night blindness and is associated with low pre albumin levels after RYGBP.
- Commercial daily oral supplement of up to 3500 IU of vitamin A is available and this accounts for 70% of recommended daily intake.
Zinc levels are found to be low in 6% of patients 1 year after RYGBP.
- Obese patients may already have zinc deficiency before surgery because zinc is sequestrated in body fat resulting in lower bioavailability.
- It may be that up to 60mg of oral supplements daily is required and is important especially during pregnancy to prevent fetal congenital problems.
Copper deficiency is uncommon and may occur many years later.
- It may have haematological and neurological consequences.
Routine vitamin and mineral supplements post RYGBP
It is important for patients to be prescribed chewable or liquid multivitamin supplements immediately after RYGBP, that is easily swallowed and has at least 200% recommended daily intake (RDI), that contains 18mg elemental iron, 400 microgram folic acid, 1000microgram vitamin B12, 1700-2000mg calcium, 1000-2000IU vitamin D with sufficient vitamin A, zinc and copper.
Blood test periodically (2 to 4 times a year) may be needed and much higher replacement doses of individual elements are needed if any specific deficiency is detected.
RYGBP compared with laparoscopic sleeve gastrectomy
There is no doubt that the RYGBP is a superior operation compared to the sleeve gastrectomy, in terms of weight loss and resolution of medical co-morbidities. Large numbers of this operation has been performed and traditionally it is still regarded as the gold standard or the measuring stick for bariatric surgery.
In Australia the RYGBP is less popular than in North America and certain parts of Europe, with greater number of surgeons preferring the sleeve gastrectomy as the primary procedure. We are more likely to recommend RYGBP for corrections of certain anatomical problems (complications from restrictive procedures) or revisions after previously failed surgeries (for inadequate weight loss or weight re-gain).
In Australia because of the relatively late introduction of RYGBP, we have definitely benefited from the latest research attesting to the equivalent efficacy of the laparoscopic sleeve gastrectomy (equally effective in producing significant weight loss, improve glucose homeostasis, blood pressure control and lipid profile). The sleeve gastrectomy is definitely superior in terms of the relative technical simplicity of the operation, good patient tolerance, rapid recovery, shorter length of stay in hospital, minimal follow up schedules and protocols, and minimal long term complications (of internal hernias, bowel adhesions), less dumping side effects and nutritional sequelae.
Recent systematic review and meta-analysis of Roux Y gastric bypass and stand alone laparoscopic sleeve gastrectomy have found similar results in terms of T2DM remission and weight loss between the two operation in the short term (1 to 3 years).
The gastric bypass has slightly better results but there are no statistical significant differences. The reported diabetes remission rate was 67 and 56% respectively (at 3 months) with modest additional results 76 and 68% respectively (at 12 months), obviously patients had greater weight loss at 12 months. With up to 3 years follow up the conclusion was that there were no significant differences between the two procedures. Furthermore from a diet perspective some studies have found that there were no observable differences in post op eating patterns between the sleeve gastrectomy and gastric bypass patients.
Hence it is deduced that the sleeve gastrectomy will achieve similar hormonal and metabolic benefits that traditionally only a gastric bypass can provide. With similar results on excess weight loss, resolution of medical co-morbidities, better patient tolerance, less gastro-intestinal side effects and less nutritional disturbances in the long term, it is easy to appreciate why many surgeons may advocate the laparoscopic sleeve gastrectomy as the procedure of choice.