Metabolic and Bariatric Surgery:Expected Outcomes, Merits

Philip Omotosho, MDAssistant Professor of SurgeryRush Medical College

• Review bariatric surgery as a treatment for morbid obesity

• Review the indications for bariatric surgery• Review the impact of bariatric surgery on co-

morbidity resolution

Objectives

Body Mass Index (BMI) = Weight (Kg) / Height (m2)Underweight < 18.5

Normal 18.5 – 24.9

Overweight 25 – 29.9

Class I Obesity 30 – 34.9

Class II Obesity 35 – 39.9

Morbid Obesity ≥ 40

Super Obesity ≥ 50

Definition of Obesity

Source: Behavioral Risk Factor Surveillance System, CDC.

15%–<20% 20%–<25% 25%–<30% 30%–<35% ≥35%

Prevalence* of Self-Reported Obesity Among U.S. Adults

by State and Territory, BRFSS, 2013*Prevalence estimates reflect BRFSS methodological changes started in 2011. These estimates should not be compared to prevalence estimates before 2011.

CA

MT

ID

NVUT

AZNM

WY

WA

OR

CO

NE

ND

SD

TX

OK

KS

IA

MN

AR

MO

LA

MI

IN

KY

ILOH

TN

MS AL

WI

PA

WV

SC

VA

NC

GA

FL

NY

VT

ME

HI

AK

NHMARICTNJDEMDDC

PRGUAM

• Worldwide obesity has more than doubled since 1980• In 2008, 1.5 billion adults, 20 and older were overweight. Of these

over 200 million men and nearly 300 million women were obese• 65% of the world’s population live in countries where overweight

and obesity kills more people than underweight• Nearly 43 million children under the age of five were overweight in

2010• Obesity is preventable

World Health Organization Fact SheetKey Facts

Mortality risk associated with morbid obesity

6Gray DS., Med Clin North Am. 1989; 73(1):1–13

2.5

2.0

1.5

1.0

20 25 30 35 40

BMI

MortalityRatio

Moderate VeryLow Low Moderate High Very

High

MenWomen

X

• Although weight may be reduced acceptably with non-surgical means, most patients fail to maintain a reduced weight

• Indications for bariatric surgery:BMI ≥ 40 BMI ≥ 35 plus associated significant obesity-related comorbidityFailure of non-surgical weight loss attempts

1991 NIH Consensus Development Conference on Gastrointestinal Surgery for Severe Obesity

Restrictive Adjustable Gastric Banding

Sleeve Gastrectomy

Combined Modality(Both restrictive and malabsorptive mechanisms)

Roux-en-Y Gastric Bypass

Biliopancreatic Diversion with Duodenal Switch

Classification

• Appetite Control

• Glucose and Lipid Metabolism

• Insulin Homeostasis

• Regulatory Peptides

Surgically-induced changes in the entero–encephalic endocrine axis (Metabolic Surgery)

Beyond Weight Loss

Adjustable Gastric Banding

• FDA approved in 2001 for implantation in the United States

• Non-resectional• Placed just below the esophagogastric

junction, creating a “virtual pouch”• Adjusted via subcutaneous access port

Adjustable Gastric Banding

Subcutaneous Port / Huber needle

Sleeve Gastrectomy

• Originally performed as the restrictive component of the duodenal switch procedure

• Risk management strategy for severely obese or high risk patients

• Substantial improvement in comorbidities in 1-2 yrs followed by a second-stage operation – RYGB or BPD/DS

• Early reports emerged of substantial weight loss with sleeve gastrectomy alone

Sleeve Gastrectomy

Roux-en-Y Gastric Bypass

• Reduced stomach capacity (small pouch)

• Malabsorptive limb• No resection• Weight loss from both

restriction and malabsorption

• Considered the gold standard for bariatric surgery

15

Biliopancreatic Diversion with Duodenal Switch

• Buchwald Meta-analysis 22,094 patients

• Operative mortality – Restrictive procedures 0.1%

– RYGB 0.5%

– BPD/DS 1.1%

Buchwald H, et al: Bariatric Surgery: A systematic review and meta-analysis. JAMA 292:1724-1737, 2004

Surgical Risk – Perioperative Mortality

Surgical outcomes – Risk

18N Engl J Med 2009;361:445-54.

Surgical outcomes

Surgery decreases long-term mortality, morbidity, and healthcare use in morbidly obese patients

Total direct healthcare cost for control patients was 45% HIGHER than for bariatric surgery patients

• 5-year mortality rates

– 0.68% bariatric surgery patients

– 6.17% control patients

19

Christou et al. Ann Surgery 2004

Outcomes of bariatric procedures

20

Sjöström et al. N Engl J Med. 2007; 357 (8): 741-52

Sjöström et al. 357 (8): 741, NEJM ; August 23, 2007

Long-term Weight Loss Outcomes: SOS Study

Bariatric Surgery Efficacy – Weight Reduction

• 50-60% EWL at 1 year– Some studies report EWL ~ 80% at 1 year (Schauer)

• Long term results?– 84% EWL | 3yrs | Boza et al. Mean preop BMI 37– 55% EWL | 5 years | Bohdjalian et al. Mean preop BMI 48.2

– 48% EWL | 8 years | Eid et al. Mean preop BMI 66

Sleeve Gastrectomy

Hutter MM et al. Ann Surg 2011; 254:410-20

Reduction in BMI

Obesity and Diabetes RiskObesity and Diabetes Risk

0

20

40

60

80

100

<20 20-25 25-30 30-35 35-40 >40

BMI Levels

Incidence of New Casesper 1000 Persons/Year

-

Knowler WC et al. Am J Epidemiol 1981

Overweight

19

Obese

30

Morbidly Obese

45-65

Classic Pathogenesis of Type II Diabetes

26

1 •Excess Energy Intake•Diminished Energy Expenditure

2 •Increase Body Weight•Increase Insulin Resistance

3 •Type II Diabetes

Evidence Based Pathogenesis of Type II

Diabetes

27

Perturbation of energy/glucose homeostasis

Behavior

Genetic

Environment

Obesity Diabetes

Surgical Treatment of Diabetes

Ann Surg 1987; 206(3):316-23

- Cohort of 42 pts with Type 2 DM- Post-operative normalization of fasting blood glucose,

fasting insulin, and HbA1c- Improvement in insulin release, insulin resistance

and utilization of glucose

Buchwald, H. et al. 2004

Bariatric surgery: a systematic review and meta-analysis

989

% Resolution (95% Confidence Interval)

0 20 40 60 80 100

98.9 (96.8, 100.0)

47.9 (29.1, 66.7)

83.8 (77.3, 90.1)

Duodenal Switch

Gastric Bypass

Gastric Banding205

288

Type 2 DM Remission

Surgery (N=30) Control (N=30)

Remission in % (N) 73% (22/30) 13% (4/30)

Achieving A1C < 6.2% in % 80% (N=24) 20% (N=6)

Medication use (N) 4 28

Weight loss (mean±SD) in % 20±9.4 1.4±4.9

Excess wt loss (mean±SD) % 62.5 4.3

Change in BMI (kg/m2) - 7.4 - 1.5Dixon, JB et al. JAMA 2008;299:316-323

LAGB: Weight Loss and Diabetes Remission

N Engl J Med 2012. Copyright © 2012 Massachusetts Medical Society.

Schauer P. et al.

Schauer P. et al.

Schauer P. et al.

N Engl J Med 2012. Copyright © 2012 Massachusetts Medical Society.

Mingrone G. et al

Bariatric Surgery Efficacy – Hyperlipidemia

Bariatric Surgery Efficacy – Obstructive Sleep Apnea

Sugerman, H. et al. Ann Surg 1999; Vol. 229(5): 634–642

Efficacy – Pseudotumor Cerebri

Malik SM et al. World J Diabetes 2012; 3(4): 71-79

“Bariatric surgery should be considered along with other medical and life-style alterations as first line therapy in PCOS women with obesity and MS.”

Bariatric Surgery Efficacy – PCOS

Torquati et al. J Am Coll Surg 2007;204:776–783

Efficacy – Cardiovascular Morbidity

Torquati et al. J Am Coll Surg 2007;204:776–783

Efficacy – Cardiovascular Morbidity

,

Anatomic Modifications Result in Alteration of GI Hormone Activity

The Foregut Theory– Exclusion of the duodenum

results in inhibition of a putative signal that is responsible for insulin resistance and/or abnormal glycemic control (T2DM)

Rubino et.al, Ann Surg, 2006

The Entero-Insular Axis

The Hindgut Theory– The more rapid delivery of undigested

nutrients to the distal bowel upregulates the production of L-cell derivatives such as GLP-1

Mason E. Obes Surg 2005 15, 459-461

The Entero-Insular Axis

‘…Reflects the enormous positive effects of bariatric surgery on the metabolic complications of severe obesity, including type 2 diabetes mellitus, sexual hormone dysfunction in both men and women (polycystic ovarian syndrome), non-alcoholic liver disease, and lipid metabolism (both cholesterol and triglycerides), but maintains in its name the positive effect of weight loss on pressure-related phenomenon (baros or bariatric) such as joint disease, GERD, urinary incontinence, obesity hypoventilation, venous stasis disease, and pseudotumor cerebri.’

Harvey Sugerman, MD

Conclusion