An Overview of Bariatric Surgery

1
An Overview of Bariatric Surgery

• Kristin Dermody
• Angela Illing
• May 23, 2005

2
THE OBESITY EPIDEMIC
3
A Quick Background of Obesity

• Derived from the Latin word obesus to devour
• Definition having a very high amount of body fat
  in relation to lean body mass
• Classifications using Body Mass Index (BMI)

4
BMI Categories

• A BMI of Classifies one as
• lt18.5 Underweight
• 18.5-24.9 Normal weight
• 25-29.9 Overweight
• 30-34.9 Obesity Class I
• 35-39.9 Obesity Class II
• 40-49.9 Obesity Class III
• 50 and above Super Obesity

5
Obesity is a BIG problem

• 1.7 billion worldwide are overweight or obese
• The US has a higher percentage of overweight and
  obese people than any country in the world
• And the numbers are growing

6
US Incidence of Obesity

• Approximately 2/3 of the United States population
  is overweight.
• Of those, almost 50 are obese.
• In total, approximately 5 of the US population
  is morbidly obese
• Alarmingly, the BMI subgroups growing the most
  quickly are 35 or higher and 40 or higher.

7
Massachusetts Not-so-Phat Facts

• 55 of Mass adults ? overweight or obese
• Of these obese adults
• 18 non-Hispanic white
• 30 non-Hispanic black
• 22 Hispanic
• 24 of Mass high school students ? overweight or
  at risk of becoming overweight
• Obesity rate among Mass adults by 81 from
  1990 to 2000

• CDC BRFSS, 2002 CDC YRBSS, 2003

8
History of Obesity
1985
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Potential Consequences of Obesity

• Obesity is associated with a rise in many
  comorbid conditions, including
• Type 2 Diabetes
• Hyperlipidemia
• Hypertension
• Obstructive Sleep Apnea
• Heart Disease
• Stroke
• Asthma
• Back and lower extremity weight-
• bearing degenerative problems
• Cancer
• Depression
• AND MORE!

11
CVD Obesity

• Fact Obesity contributes to these co-morbid
  conditions, however
• Recent JAMA article by Gregg et al suggests CVD
  risk factors across all BMI groups over past
  40 years
• Suggest Overweight not quite as bad as it once
  was, considering other factors
• Risk r/t awareness, aggressive
  identification, pharmacological tx of high chol,
  HTN.
• Note Obese persons still have risk factor
  levels vs..lean persons.

Gregg EW, et al. Secular Trends in Cardiovascular
Disease Risk Factors According to Body Mass Index
in US Adults. JAMA, 20052931863-1874
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Impact of Obesity

• These comorbid conditions are together
  responsible for more than 2.5 million deaths per
  year worldwide.
• This is in addition to billions of dollars in
  healthcare costs and lost productivity.

World Health Organization, World Health Report
2002
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Obesity and Life Expectancy

• Recent NEJM article If current rates of
  obesity are left unchecked, the current
  generation of American children will be the first
  in two centuries to have a shorter life
  expectancy than their parents.
• The life-shortening impact of obesity (currently
  estimated at 1/3 to ¾ year) could rise to 2 to 5
  years, or more, as obese children spend more
  years at risk for comorbid conditions.

Olshansky SJ, et al. A Potential Decline in Life
Expectancy in the United States in the 21st
Century. NEJM, 352(11)1138-1145, 2005
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Obesity and Life Expectancy

• The morbidly obese are perhaps the worst off
• Compared to a normal-weight person, a 25-year-old
  morbidly obese man has a 22 reduction in
  expected remaining lifespan.
• This is an approximate loss of 12 YEARS!
• This number will also likely grow if the
  ever-expanding numbers of currently obese
  children continue as obese adults

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TREATING OBESITY
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Weight Loss Strategies

• Diet therapy
• Increased Physical Activity
• Pharmacotherapy (e.g., Orlistat, Meridia)
• Behavioral Therapy
• Hypnosis
• Any combination of the above

17
Bariatric Surgery

• An effective treatment for combating obesity

18
Bariatric Surgery

• 1991 NIH establishes guidelines for the surgical
  therapy of morbid obesity
• Recommends BMI criteria
• BMI gt 40
• BMI gt 35 significant comorbidities
• This therapy now referred to as Bariatric Surgery

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Types of Bariatric Surgery

• Purely Restrictive
• Gastric Balloons (not approved for use in USA)
• Vertical-banded gastroplasty
• Gastric adjustable banding (BWH)
• Restrictive gt Malabsorptive
• Short-limb/Roux-en-Y gastric bypass (BWH)
• Long-limb/distal Roux-en-Y gastric bypass
• Malabsorptive gt Restrictive
• Biliopancreatic diversion (BPD)
• BPD with duodenal switch
• Very long limb Roux-en-Y gastric bypass
• Purely Malabsorptive
• Jejunoilieal bypass
• Jejunocolonic bypass

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A Brief History of Bariatric Surgery

• First developed
• Pts with short bowel syndrome ? weight loss
• First weight loss surgeries (ca. 1950s)
• Intestinal bypass
• Low-risk surgically BUT many patients developed
  serious and often fatal complications
• Biliopancreatic diversion
• Effective BUT with high risk and many
  complications

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Evolution of the Roux-en-Y

• Gastric partitioning (Roux-en-Y GBP)
• Based on observations of weight loss in pts
  receiving subtotal gastric resections for other
  conditions
• 1967 First performed
• Continues to be studied and refined

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Roux-en-Y

• Open
• 2 hour procedure
• 3 days in-house
• 4 weeks Return to work
• 60-70 EBW loss _at_ 2 yrs
• 0.5-1.0 Risk of Death
• Dumping Syndrome
• Laparoscopic
• 2-4 hour procedure
• 3 days in-house
• 2-3 weeks Return to work
• 60-70 EBW loss _at_ 2yrs
• 0.5-1.0 Risk of Death
• Dumping Syndrome

Data based on averages.
23
Evolution of Gastric Banding

• 1970s
• Alternative to Roux-en-Y in Europe Scandinavia
• 1980s
• Adjustable silicone band developed
• 1990s
• Laproscopic techniques for placement developed

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Gastric Banding

• Adjustable Lap Band
• 1 hr procedure
• 1 day in-house
• 1 wk Return to work
• 40-45 EBW loss _at_ 2 yrs
• lt0.1 Risk of Death
• Self-sabotage easier

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Who Gets Bariatric Surgery?

• Gender
• 19 Males
• 72.6 Females
• (8 gender not reported)
• Age
• Mean age 39 years
• Range 16-64 years
• BMI
• Mean BMI 46.9
• Range 32.3-68.8

• Buchwald H, et al. Bariatric Surgery A
  Systematic Review and Meta-analysis. JAMA,
  141724-37, 2004

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Medical Nutrition Therapy and
The Post-op Bariatric Patient
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Post-Surgical Nutrition

• Balanced/healthy diet
• Liquids to pureed to soft to solid
• High nutrient density, quality
• Modified in lactose, fat, sugar
• Adequate fluid
• Portion Control
• Meal Periods/Eating time
• MVI/MIN
• Ca (gt1200mg/d) D (10-20mg)
• Folate (800-1000mcg) B12
• Iron (45-100mg elemental pre-menstrual)
• Vitamin C (75-100mg)
• Thiamin
• Self-monitoring
• Eating triggers/behaviors
• Exercise

Time line may vary among institutions
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Post-Op Roux-En-Y Diet

• Stage One (1 day)
• Water and clear liquids
• Non-caloric, non-carbonated, non-caffeinated
  liquids
• Fluid goal 28-32oz/d
• Stage Two (14 days)
• High protein, low sugar beverages
• Fluid goal 56oz
• Protein goal 60-70g/d
• Chewable MVI Ca

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Post-Op Roux-En-Y Diet

• Stage Three (4 weeks)
• 5 2oz servings diced protein
• Fluid goal 56oz
• Protein goal 60-70g
• Chewable MVI Ca
• Stage Four (4 months)
• 3 meals, 2 snacks
• 850kcal/d
• Fluid goal 56oz
• Protein goal 60-70g
• Chewable MVI Ca

• Stage Five (ongoing)
• Regular Meals
• 1200-1500kcal
• Fluid Protein goals same as above

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Post-op Lap Band Diet

• Stage One (1 day)
• Water Clear Liquids
• Non-carbonated, non-caffeinated, non-caloric
  liquids
• Fluid goal 28-32oz/d
• Stage Two (14 days)
• 5-8oz servings of High Protein, low sugar
  Beverage
• Fluid goal 56oz
• Protein goal 50-60g
• Chewable MVI Ca

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Post-op Lap Band Diet

• Stage Three (14 days)
• Pureed Foods, Semi solids
• 2 small meals, 3 snacks
• Fluid goal 56oz
• Protein goal 50-60g
• Chewable MVI Ca
• Stage Four (ongoing)
• Regular meals 3 meals,2 snacks (1000-1200)
• Fluid goal 56oz
• Protein goal 50-60g
• Chewable MVI Ca

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Post-Surgical Nutrition Exercise

• RD seen frequently
• 1m ?3m? 6m? 1yr
• Exercise
• No heavy lifting or exercise 6-8wks post-op
• Walking daily OK, encouraged
• After cleared, strength training important to
  help skin stretch back
• Helps with weight loss in the long run

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When Surgery and Follow-Up Go Well
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Efficacy of Bariatric Surgery for Weight Loss

• Mean percentage excess weight loss
• 61.2 - All Patients
• 47.5 - Gastric Banding
• 61.6 - Gastric Bypass
• 68.2 - Gastroplasty
• 70.1 - BPD or duodenal switch

• Buchwald H, et al. Bariatric Surgery A
  Systematic Review and Meta-analysis. JAMA,
  141724-37, 2004

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Roux-en-Y Metabolic Sequelae

• Human body regulates nutrient intake over time by
  secreting hormones
• Over 40 hormones play a role in regulation of
  feeding.

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Roux-en-Y Metabolic Sequelae

• Two types
• Satiety hormones
• Short-term
• Help regulate meal size daily intake
• Secretion decreases meal size reduces time to
  stop
• Includes (among others) cholecystokinin, amylin,
  glucagon-like-peptide 1 (GLP-1), enterostatin,
  and bombesin
• Adiposity hormones
• Long-term
• Related to energy stores
• Secretion delays onset of beginning of meal
• Includes insulin, leptin

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Roux-en-Y Metabolic Sequelae

• Also of note is ghrelin, the endogenous ligand
  for the growth hormone secretagogue receptor
• Mostly secreted in the fundus of the stomach
  (part bypassed in RYGB)
• Contrary to satiety hormones, ghrelin is
  orexigenic i.e., increases appetite (fasting
  increases levels)

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Roux-en-Y Metabolic Sequelae

• Plasma ghrelin normally increases after
  non-surgical weight loss
• This supports long-term weight homeostasis
• Proportional to lean body mass
• Initial report showed circulating plasma ghrelin
  greatly decreased in pts s/p RYGB
• Past theory exclusion of the fundus of the
  stomach responsible for lower ghrelin levels (and
  therefore greater weight loss)

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Roux-en-Y Metabolic Sequelae

• Studies since then have shown no change or
  increase in ghrelin after bypass
• Additionally, found that post-pyloric nutrient
  stimulation vs.. stomach distention responsible
  for changes in ghrelin levels
• Does not support idea that bypassing stomach
  fundus responsible for changes, if any, in
  ghrelin levels
• Overall, still not well understood

• Strader AD, et al. Gastrointestinal Hormones and
  Food Intake. Gastroenterology, 128175-91, 2005

40
Roux-en-Y Metabolic Sequelae

• Further investigation is needed, but thought that
  one reason certain types (i.e., RYGB) of
  bariatric surgery are successful at reducing food
  intake and causing weight loss may be related to
  enhanced secretion of satiety signals (ghrelin or
  others).

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Effect on Comorbid Conditions

• Diabetes
• 76.8 - Completely resolved
• 86.0 - Resolved or improved
• Hyperlipidemia
• 70 - Improved
• HTN
• 61.7 - Resolved
• 85.7 - Resolved or improved
• Obstructive Sleep Apnea
• 83.6 - Resolved
• 85.7 - Resolved or improved

• Buchwald H, et al. Bariatric Surgery A
  Systematic Review and Meta-analysis. JAMA,
  141724-37, 2004

42
Metabolic Changes and Diabetes

• Many metabolic changes contribute to improvement
  and/or resolution of DM s/p bariatric surgery
• Recovery of acute insulin response
• Decreases of inflammatory indicators (C-reactive
  protein and interleukin 6)
• Improvement in insulin sensitivity correlated
  w/increases in plasma adiponectin
• Changes in the enteroglucagon response to glucose
• Reduction in ghrelin levels (s/p RYGB, but not
  banding)
• Improvement in beta cell function (s/p banding,
  but not RYGP)

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Effect on Quality of Life

• Studies show overall QOL greatly improved
• Relief from comorbidities
• Improved appearance
• Perception of improved
• Well-being
• Social function
• Body self-image
• Self confidence
• Ability to interact with others
• Increased time spent in recreational and physical
  activities
• Enhanced productivity
• Increased economic opportunities
• Often new employment
• More lucrative employment

44
PROBLEMS AND COMPLICATIONSof Bariatric Surgery
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Possible Complications of Bariatric Surgery

• General Complications
• Pulmonary embolism
• Incisional hernia
• Gallstone formation
• Major wound infection and seroma
• Abdominal fluid collection
• Subphrenic abscess
• Peritonitis

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Procedure-Specific Complications (RYGB)

• Anastomotic or staple-line leak
• Acute gastric distention
• Staple-line disruption
• Stomal stenosis
• Stomal ulceration
• Small-bowel obstruction
• Occlusion of Roux limb

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Intermediate Complications

• Wound Infection
• Intra-abdominal bleed
• Gastric remnant necrosis
• Ischemic Roux-limb
• Internal hernia

48
Long-Term GI Complications

• Nausea
• Constipation
• Abdominal pain
• Marginal ulcers
• Incisional hernias
• Vomiting
• Diarrhea
• Gallstones
• Gastritis
• Intestinal Obstructions

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Incidence of Complications

• Operative mortality (lt 30 days)
• 0.1 for Purely Restrictive Procedures
• 0.5 for Gastric Bypass
• 1.1 for BPD or Duodenal Switch

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Long-Term Nutrition Complications

• Malnutrition
• Vitamin and mineral deficiencies
• Weight loss failure
• Dehydration
• Anemia
• Dumping Syndrome
• Hair loss
• Dry skin

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Risk of Vitamin and Mineral Deficiencies Post-op

• Calcium and Vitamin D
• Reduced absorption d/t bypassed duodenum,
  proximal jejunum (R-en-Y)
• Life-long supplements mandatory
• Iron
• Absorption decreased d/t decreased contact of
  food with gastric acid reduced conversion of
  iron from ferrous to ferric form (MVI)
• Vitamin B12
• Absorption decreased d/t decreased contact with
  intrinsic factor
• 60 of patients require long term supplementation
  of B12
• Thiamine
• Connection to Wernickes syndrome
• Cases not well documented

52
Post-Surgical Eating Avoidance Disorder (PSEAD)

• De novo synthesis of eating disorders post-GBP
• No history pre-operatively
• Do not fit criteria for AN, BN, or BED
• Classify now as EDNOS
• Characteristics consistent enough to suggest new
  eating disorder

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Post-Surgical Eating Avoidance Disorder (PSEAD)

• Proposed Criteria
• Previous h/o morbid obesity followed by bariatric
  surgery over the last 2 years
• Higher speed of weight loss than the average
• Use of purgative strategies or excessive
  reduction of food intake, related or not related
  to binge eating episodes

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Post-Surgical Eating Avoidance Disorder (PSEAD)

• Proposed Criteria
• Reaction of extreme anxiety /or negative
  attitude when nutritional correction introduced
• Intense fear of going back to pre-op wt
• Does not accept attempts to interrupt the wt loss
  
• Denies doing something exaggerated that account
  for loss
• Perceives a positive return with wt loss in spite
  of evidence to the contrary

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Post-Surgical Eating Avoidance Disorder (PSEAD)

• Proposed Criteria
• Body image dissatisfaction or distortion
• Follow-up nutritional tests (such as laboratory
  tests) alterations that are significant and/or
  not in line with the surgical technique,
  maintained for more than 2 months after initial
  interventions
• Exclude AN and BN, according to DSM IV
• Exclude Simple Phobias (I.e., Food or Choking
  Phobia) according to DSM IV
• Exclude organic causes as the most probable
  factor for excessive weight loss

• Segal et al. Post-Surgical Refusal to Eat
  Anorexia Nervosa, Bulimia Nervosa or a New Eating
  Disorder? A Case Series. Obes Surg, 14353-359,
  2004

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Post-Surgical Eating Avoidance Disorder (PSEAD)

• A proposed ED classification
• Not yet part of the DSM IV

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ED Contraindication for GBP?

• Pt with h/o of AN or BN likely not a good
  surgical candidate
• Pt at high risk for malnutrition after surgery
• Some with h/o ED receive surgery
• Important to screen carefully before AND monitor
  closely post-op to prevent relapse of disorder,
  malnutrition.

58
Long Term Impact Future Directions
59
Long-Term Changes Weight Regain

• One study of 342 gastric bypass pts showed
  excellent long-term weight maintenance
• weight loss at
• 1 year (89)
• 2 years (87)
• 5 years (70)
• 10 years (75)
• However, potential for pouch stretch,
  self-sabotage, etc. leading to weight regain over
  time.
• Surgery relatively new, will have to wait and
  reanalyze data in a few years.

60
Long-term changes in energy expenditure and body
composition after massive weight loss induced by
gastric bypass surgery
Das SK, et al. Am J Clin Nutr. 20037822-30.
61
Study EE Body Composition

• Objective
• To determine changes in energy expenditure and
  body composition with weight loss after gastric
  bypass surgery to identify pre-surgery
  indicators of weight loss.

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Study EE Body Composition

• Design Methods
• Included 30 obese men and women
• Average age 39.0 9.6 y
• Average BMI (kg/m2) 50.1 9.3
• Tested longitudinally under weight-stable
  conditions before surgery and after weight loss
  and stabilization (14 2 mo)
• Measured total energy expenditure (TEE), resting
  energy expenditure (REE), body composition, and
  fasting leptin

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Study EE Body Composition

• Results
• Weight loss 53.2 22.2 kg body weight
• Significant reduction in REE (-2.4 1.0 MJ/d P
  lt 0.001) and TEE (-3.6 2.5 MJ/d P lt 0.001).
• Changes in REE predicted by changes in fat-free
  mass and fat mass
• Average physical activity level (TEE/REE) was
  1.61 at both baseline and follow-up (P 0.98)
• Weight loss predicted by baseline fat mass and
  BMI but not by any energy expenditure variable or
  leptin.
• Measured REE at follow-up was not significantly
  different from predicted REE.

64
Study EE Body Composition

• Conclusions
• TEE and REE decreased by 25 on average after
  massive weight loss and weight stabilization
  after gastric bypass
• Decreases in REE largely or completely predicted
  by decreases in body FFM and fat mass
• Fasting leptin at baseline found not to be a
  predictor of energy efficiency/changes, as some
  previous studies had shown

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Study EE Body Composition

• Conclusions
• Suggested further studies to examine other
  explanations for variability in weight loss
  between patients after gastric bypass surgery
• ? Psychological, behavioral factors
• Suggested permanent reduction in energy intake
  critical for long-term weight management

66
Other Future Weight Loss Strategies

• Gastric stimulation idea of placing a
  pacemaker-like device in stomach to control
  contractions release of hunger/satiety hormones
• Hormone therapy - exendin-4
• Hormone produced in Gila monster salivary gland
• Similar to GLP-1 in humans
• Reduces gastric emptying
• Lowers fasting plasma glucose
• Reduces food intake
• May prove effective therapy for DM, obesity

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OTHER CONCERNS
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Nutrition Support in the Critically Ill GBP
Patient

• Enteral feeding possible, if warranted
• Tube surgically placed in excluded stomach
  (RYGBP)
• Nasoenteric tube placed endoscopically through
  pouch
• If neither option possible (e.g. if pt has
  anastomotic leak) ?TPN.

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Bariatric Surgery in Special Populations

• Adolescents
• Elderly (over 60)

70
Adolescents

• Few medical centers currently performing
  bariatric surgery on this population
• Only extreme cases
• Highly controversial given incomplete growth
  period
• Specialized medical team only

71
Elderly

• Advanced age common contraindication to surgery
• Research suggests age may not be as indicative of
  outcome as once believed
• Successful GBP cases in 60

St.Peter, Shawn. Impact of Advanced Age on Weight
Loss and Health Benefits After Laparoscopic
Gastric Bypass. Arch Surg 140165-1682005
72
Spouses of GBP Patients

• Study by Madan AK, et al (2005) showed gastric
  bypass patients spouses who are obese are more
  likely to have weight gain while the patients
  lose weight after surgery
• Suggest pre-operative counseling for spouses or
  even consider them for surgery as well

73
Summary

• Bariatric surgery is a seemingly effective
  therapy for morbid obesity that is gaining in
  popularity and prevalence
• Bariatric surgery provides significant
• Loss of excess body weight
• Relief from comorbidities
• DM, HTN, hyperlipidemia
• Improvement in QOL for patients
• However, these surgeries put pts at risk for
• Post-op complications mortality
• Nutritional deficiencies GI complications
• Psychosocial complications

74
References

• Kim JJ, et al. Surgical Treatment for Extreme
  Obesity Evolution of a Rapidly Growing Field.
  Nutr Clin Prac 18109-23, 2003
• Buchwald H, et al. Bariatric Surgery A
  Systematic Review and Meta-analysis. JAMA,
  141724-37, 2004
• Olshansky SJ, et al. A Potential Decline in Life
  Expectancy in the United States in the 21st
  Century. NEJM, 352(11)1138-1145, 2005
• Merkle EM, et al. Roux-en-Y Gastric Bypass for
  Clinically Severe Obesity Normal Appearance and
  Spectrum of Complications at Imaging. Radiology,
  234(3)674-83, 2005
• Segal et al. Post-Surgical Refusal to Eat
  Anorexia Nervosa, Bulimia Nervosa or a New Eating
  Disorder? A Case Series. Obes Surg, 14353-359,
  2004
• Madan AK, et al. Weight changes in spouses of
  gastric bypass patients. Obes Surg, 15(2)191-4,
  2005

75
References

• Strader AD, et al. Gastrointestinal Hormones and
  Food Intake. Gastroenterology, 128175-91, 2005
• Das SK, et al. Long-term changes in energy
  expenditure and body composition after massive
  weight loss induced by gastric bypass surgery. Am
  J Clin Nutr. 20037822-30.