THE GROWING PROBLEM OF OBESITY
Educational Objectives
| The goal of this program is to improve the surgical management of morbidly obese patients. After hearing and assimilating
this program, the clinician will be better able to:
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 | 1. Compare advantages, complications, and efficacy of bariatric operations.
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| 2. Describe new interventions and products for bariatric surgery now in development.
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| 3. Utilize the obesity surgery-mortality risk score to stratify perioperative risk in candidates for bariatric surgery.
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| 4. Identify patients at risk for intra-abdominal hypertension and end organ failure.
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| 5. Review surgical methods for abdominal decompression and management of abdominal compartment syndrome.
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Faculty Disclosure
In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty and members of the planning
committee to disclose relevant financial relationships within the past 12 months that might create any personal conflicts of interest.
Any identified conflicts were resolved to ensure that this educational activity promotes quality in health care and not a
proprietary business or commercial interest. For this program, the following has been disclosed: Dr. Herron has received education
grants from Covidien and Ethicon Endo-Surgery. He has also been a consultant for USGI Medical. Dr. DeMaria has received
education and research support from Covidien and an education grant from Stryker Endoscopy. He has been a
consultant for Power Medical Interventions and a research advisor for the Surgical Review Corporation. Dr. Champion has
been on the Speakers’ Bureau and is a consultant for Ethicon Endo-Surgery. The planning committee reported nothing to disclose.
Acknowledgements
Dr. Herron spoke at the Postgraudate Course in General Surgery, held March 27-29, 2008, in San Francisco, CA,
and sponsored by the Department of Surgery of the University of California, San Francisco, School of Medicine. Dr.
DeMaria was recorded at the 37th Annual Postgraudate Course in Surgery, held April 17-19, 2008, in Charleston,
SC, and sponsored by the Department of Surgery of the Medical University of South Carolina. Dr. Champion lectured
at Surgery of the Foregut Symposium, held February 18-20, 2008, in Coral Gables, FL, and sponsored by the
Section of Minimally Invasive Surgery and the Bariatric Institute of Cleveland Clinic Florida, in conjunction with the
European Surgical Institute, the Federation of Latin American Surgeons, and the Association of Latin American Endoscopic
Surgeons. The Audio-Digest Foundation thanks the speakers and the sponsors for their cooperation in the
production of this program.
| BARIATRIC SURGERY: HOW DO THE PROCEDURES COMPARE ?—Daniel M. Herron, MD, Associate Professor of
Surgery, Mount Sinai School of Medicine, New York, NY
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| Mount Sinai criteria for morbid obesity surgery: body mass index (BMI) >40 or >35 with ≥1 major comorbidity
(eg, diabetes, sleep apnea, severe hypertension) caused by obesity; age 18 to 65 yr (not absolute); multiple failures at serious
dieting; ability to comply with postoperative regimen; acceptable surgical risk
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| Roux-en-Y gastric bypass procedure (GBP): considered gold standard; now more frequently done laparoscopically
than open; most popular (150,000-180,000 performed each year); 50% to 75% loss of excess body weight; some nutritional
disturbances; relatively well tolerated; first performed in 1967; results reported in 1987 study by Sugerman et al;
complications occur but relatively well controlled (mortality <0.5% in multiple studies); mechanism of action—recent
studies suggest efficacy largely due to hormonal changes that occur after surgery (eg, decrease in ghrelin levels)
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| Laparoscopic adjustable gastric banding: second most popular bariatric procedure in United States; inflatable
gastric band placed just distal to gastroesophageal (GE) junction; purely restrictive procedure (considered by some to be
reversible or technically simple); band connected to access port placed under skin (for injection of saline); good results
possible (2005 study reported >60% weight loss after 4 yr); compared to GBP, fewer adverse events and less risk for minor
and major complications near time of surgery; however, some complications, due to fact that artificial device being
wrapped around patient’s stomach
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| Laparoscopic biliopancreatic diversion with duodenal switch (BPD/DS): creation of long banana-shaped
gastric pouch (sleeve gastrectomy); left side of stomach (including fundus) removed; extensive bypass of intestine;
highly malabsorptive (although less restrictive than banding); side effects include frequent loose bowel movements, excessive
flatus, bromidrosis and halitosis, and food intolerances; technically complex (difficult to perform), lengthy, with
high complication rate (therefore, least common bariatric operation in United States); produces greatest weight loss of
any operation available (in patients with BMI >50, 80% excess body weight loss; durable over 8 yr)
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| Vertical (sleeve) gastrectomy: initially used as first-stage operation for BPD-DS; now being evaluated as primary operation;
recent study reported 59% loss of excess body weight at 1 yr, lower complication rate than GBP; removal of fundus
(area of stomach that produces grhelin) probably accounts for efficacy; controversial whether procedure still
investigational
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| WHAT’S NEW IN BARIATRIC SURGERY —Dr. Herron
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| Primary goal: to decrease invasiveness of procedures (therefore, fewer complications, better patient acceptance, and
greater ability to treat larger segment of population)
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| Intragastric balloon: among first endoscopic interventions for weight loss; simple procedure (takes 15 min); some
postprocedure complaints of epigastric pain, nausea, and vomiting (generally resolve after 48 hr); produces ≈34% to 38%
loss of excess body weight at 6 mo; not approved for use in United States, and approved only for temporary use elsewhere;
possible indications (preoperative weight loss before permanent bariatric operation or before nonbariatric procedure
[eg, hip replacement])
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| Endoluminal surgery: USGI TransPort— 4-lumen steerable lockable endoscopic access device; can place any number
of endoscopic suturing or tissue manipulation devices; at speaker’s institution, currently using this technology to revise dilated
GBP pouch and reduce diameter of stoma in patients in whom GBP has failed and who have regained weight (results
of small preliminary study); StomaphyX device—endoluminal fastener and delivery system; device placed into stomach;
tissue sucked into StomaphyX via vacuum aspiration; T-fastener then stapled across pieces of tissue drawn into StomaphyX
device
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| Endoscopic malabsorptive procedures: endoluminal sleeve—anchored endoscopically at first portion of duodenum,
then positioned through proximal portion of duodenum and jejunum; sleeve allows food to pass while preventing
mixing of chyme with biliary and pancreatic secretions; in recent study, rats treated with procedure experienced weight
loss and had lower caloric intake; may be used in humans in next few years
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| Electrical gastric stimulation: Transcend implantable gastric stimulator (IGS)—pacemaker-like device; has 2
leads that attach to stomach; generates sensation of satiety; initial speculation that use of device would result in 30% to
40% loss of excess body weight; results—Screened Health Assessment and Pacer Evaluation (SHAPE) trial
(multicenter double-blind randomized controlled US trial) reported no deaths or major complications, but primary
efficacy end point not met (device subsequently withdrawn); Medicure IGS device (under development)—stomach
sensor as well as gastric stimulator; output triggered by food coming into stomach; has 6 leads that attach to stomach;
early study showed 27% loss of excess weight; however, second study showed only 5-kg weight loss; trial currently
under way to investigate use in treatment of diabetes
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| VBLOC system (EnteroMedics): uses high-frequency electrical stimulation to intermittently block messages transmitted
from vagal nerve; system includes implantable pacemaker-like device with 2 leads to stomach; randomized prospective
trial currently under way to evaluate efficacy (preliminary data show 29% loss of excess weight at 9 mo);
disadvantages—device needs frequent recharging; weight loss results may be inferior to those with GBP or other operations;
long-term outcomes not yet known
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| Sympathetic nerve stimulation: neuromodulation therapy that involves stimulating splanchnic nerve now in development;
no clinical or animal studies yet; advantages of neuromodulation devices—implantation minimally invasive;
well tolerated; no interference with intestinal tract as with GBP and other operations; adjustable and reversible; low risk
for complications; can be used in patients in whom GBP has not produced adequate weight loss; disadvantages—
require high power and frequent recharging; cumbersome and awkward; require patient compliance; weight loss results
may be limited, and unclear whether results lasting; not known whether causing satiety sufficient to prevent overeating
and cause weight loss
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| BARIATRIC SURGERY RISK REDUCTION —Eric J. DeMaria, MD, Professor of Surgery, Vice Chair and Chief, Network
General Surgery, and Director, Endosurgery/Bariatric Surgery, Duke University School of Medicine, Durham, NC
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| Introductory remarks: some evidence of improvement in quality of care of bariatric surgery patients (study by
Agency for Healthcare Research and Quality [AHRQ] showed 79% reduction in mortality between 1998 and 2004);
overall, low mortality risk associated with bariatric surgery; however, speaker suggests that bariatric surgery as specialty
has not addressed question of whether risk uniformly low for all patients undergoing treatment
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| Factors related to higher preoperative mortality risk: male sex; comorbidity status; higher BMI; advanced age;
complications after surgery; surgeon inexperience; revision procedures (vs primary bariatric procedures); cigarette smoking
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| Obesity surgery–mortality risk score (OS-MRS): study by speaker et al; goal to create clinically useful scoring
system for stratification of mortality risk associated with bariatric surgery; prospectively collected data from 2000 patients
undergoing GBP at single institution; looked at all surgery-related mortality (including all mortality within 90
days); using univariate review and multivariate analysis, authors identified 5 independent variables that correlated with
mortality (BMI ≥50, male sex, comorbid hypertension, variable risk for pulmonary embolism [PE]; age ≥45 yr); scoring
system developed by assigning value of 1 point for each variable present (overall score 0-5 points); point scores combined
and grouped into 3 classes of risk (A [0-1 points], B [2-3 points], and C [4-5 points]) to increase evaluable number
of patients in each class; mortality risk stratified among classes significantly different (0.3% for A, 1.9% for B, 7.5% for
C)
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| OS-MRS validation project: goal to validate scoring system by looking at data from medical centers independent of
initial defining cohort; patient data submitted by 4 participating centers for analysis at coordinating center; 4431 patients
available for analysis; total number of deaths among all 4 centers, 33 (overall mortality 0.7%); only 6 patients identified
as having all 5 risk factors, and 1 center had 0 patients with 4 to 5 points (evidence of patient selection); mortality risk
stratified as significantly different between class A, B, and C patients at all 4 centers (but with some differences in absolute
values); when data combined, outcomes very similar to that seen in original patient cohort (mortality risk 0.2% for
class A, 1.2% for B; 2.4% for C)
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| Combining data from OS-MRS validation project and initial patient cohort: results—total number of
patients, 6500; total number of deaths, 68; 1% overall mortality; definite stratification of mortality risk among class A, B,
and C patients; demonstrates that stratification of risk through use of OS-MRS scoring system possible, but that risk
somewhat variable between centers
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| Validation of OS-MRS: in 15-yr study of duodenal switch operation, 1400 patients stratified according to OS-MRS;
when compared to initial cohort of patients, authors found that mortality risk for duodenal switch (stratified according to
classes A, B, and C) no different from that in GBP patients
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| Comments: OS-MRS first such system to be validated by centers independent of original patient cohort; clinically useful,
particularly due to its simplicity (can be easily calculated at bedside); consistent with other publications on risk; effective
in differentiating high- and low-risk patients
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| Potential applications of OS-MRS: improves informed consent process; need to ask if class C patients have prohibitive
risk (classification of patients as high risk enables use of risk-reduction strategies); allows credentialing entities (eg,
American College of Surgeons Bariatric Network, Surgical Review Corporation) to compare program outcomes
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| Concluding comments: OS-MRS may not be most helpful or definitive scoring system for bariatric surgery, “but at
least it is a start”; can use this type of system to assess value of measures such as preoperative weight loss; in
summary—bariatric surgery valuable; risk reduction strategies will probably become increasingly important now that
there is system for assessing risk
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| DAMAGE-CONTROL LAPAROTOMY FOR BARIATRIC EMERGENCIES —J.K. Champion, MD, Clinical Professor
of Surgery, Mercer University School of Medicine, and Director of Bariatric Surgery, Northside Hospital, Atlantic, GA
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| Etiology of bariatric emergencies: normal intra-abdominal pressure <0 to 6.5 mm Hg and varies with respiration; increased
intra-abdominal pressure can occur with any increase in volume of abdominal contents; in bariatric surgery patients,
intra-abdominal hypertension may be caused by sepsis and intra-abdominal infections associated with leaks,
intestinal obstructions, or hemorrhage
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| Definition of terms: intra-abdominal hypertension—pressure in abdomen >25 mm Hg; abdominal compartment
syndrome—intra-abdominal hypertension associated with end organ failure; results in renal insufficiency and respiratory
failure; hallmark symptoms increasing respiratory distress or signs of renal failure immediately after surgery or
within 24 hr; associated with 40% to 50% mortality
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| Clinical case scenario: surgeon operates to repair leak or closed loop obstruction; patient develops tense distended abdomen;
respiratory pressures start to increase in intensive care unit (ICU); patient requires intubation and mechanical
ventilation and develops progressive oliguria; experiences CO2 retention despite being on 100% O2 ; patient develops hypotension;
low-dose dopamine drip initiated; vasopressors required; patient fails to improve and dies 3 wk later; cause of
death end organ failure and intra-abdominal hypertension (since leak successfully repaired, autopsy reveals no intra-abdominal
infection)
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| Avoiding intra-abdominal hypertension: surgeon must have high index of suspicion; difficulty or inability to close
abdomen at end of case, or 10- to 15-mm increase in inspiratory pressure upon closing fascia, signs that incision should
be left open to decompress abdomen; in ICU, patient should be routinely monitored by measuring bladder pressure via
Foley catheter (if pressure rises to >25 mm Hg, must return to operating room to reopen abdomen)
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| Management of abdominal compartment syndrome: patient’s fascia must be opened to relieve pressure; bowel
needs to be covered to prevent evisceration and handle leakage of peritoneal fluid from abdomen; methods—temporary
closure with towel clips (closing skin loosely but leaving fascia open); Bogota bag; Gortex or polypropylene mesh closure;
Whittman patch; vacuum-assisted closure (VAC) device; after decompression, reassess abdomen every 48 hr,
change dressing, and attempt to close fascia; if fascia cannot be closed in 2 wk, employ delayed closure
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| Other recommendations for treatment of ICU patients: start feeding early (within 48 hr); pain control and sedation
(particularly if patient on ventilator to prevent extubation); thromboembolic prophylaxis; elevate head of bed 30°
to prevent aspiration; “ultraprophylaxis” (preferably with proton pump inhibitor); maintenance of tight glucose control
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Suggested Reading
Aggarwal S et al: Laparoscopic sleeve gastrectomy for morbid obesity: a review. Surg Obes Relat Dis 3:189, 2007;
Camilleri M et al: Intra-abdominal vagal blocking (VBLOC therapy): clinical results with a new implantable medical
device. Surgery 143:723, 2008; Champion JK et al: Implantable gastric stimulation to achieve weight loss in
patients with a low body mass index: early clinical trial results. Surg Endosc 20:444, 2006; Champion JK, Pories
WJ: Centers of Excellence for Bariatric Surgery. Surg Obes Relat Dis 1:148, 2005; Champion JK, Williams M:
Small bowel obstruction and internal hernias after laparoscopic Roux-en-Y gastric bypass. Obes Surg 13:596, 2003;
Cummings DE et al: Plasma ghrelin levels after diet-induced weight loss or gastric bypass surgery. N Engl J Med
346:1623, 2002; DeMaria EJ: Bariatric surgery for morbid obesity. N Engl J Med 356:2176, 2007; DeMaria EJ
et al: Obesity surgery mortality risk score: proposal for a clinically useful score to predict mortality risk in patients
undergoing gastric bypass. Surg Obes Relat Dis 3:134, 2007; DeMaria EJ et al: Validation of the obesity surgery
mortality risk score in a multicenter study proves it stratifies mortality risk in patients undergoing gastric bypass for
morbid obesity. Ann Surg 246:578, 2007; DeMaria EJ, Jamal MK: Laparoscopic adjustable gastric banding:
evolving clinical experience. Surg Clin North Am 85:773, 2005; Demaria EJ, Jamal MK: Surgical options for
obesity. Gastroenterol Clin North Am 34:127, 2005; Fernandez AZ Jr et al: Multivariate analysis of risk factors
for death following gastric bypass for treatment of morbid obesity. Ann Surg 239:698, 2004; Frezza EE: Laparoscopic
vertical sleeve gastrectomy for morbid obesity. The future procedure of choice? Surg Today 37:275, 2007;
Genco A et al: BioEnterics Intragastric Balloon (BIB): a short-term, double-blind, randomised, controlled, crossover
study on weight reduction in morbidly obese patients. Int J Obes (Lond) 30:129, 2006; Herron DM: Biliopancreatic
diversion with duodenal switch vs. gastric bypass for severe obesity. J Gastrointest Surg 8:406, 2004;
Herron DM: The surgical management of severe obesity. Mt Sinai J Med 71:63, 2004; Herron DM et al: Gastric
bypass pouch and stoma reduction using a transoral endoscopic anchor placement system: a feasibility study. Surg
Endosc 22:1093, 2008; Herron DM, Bloomberg R: Complications of bariatric surgery. Minerva Chir 61:125,
2006; Hunter JD, Damani Z: Intra-abdominal hypertension and the abdominal compartment syndrome. Anaesthesia
59:899, 2004; Kirkpatrick AW et al: The secondary abdominal compartment syndrome: iatrogenic or unavoidable?
J Am Coll Surg 202:668, 2006; Lee CM et al: Vertical gastrectomy for morbid obesity in 216 patients:
report of two-year results. Surg Endosc 21:1810, 2007; Marceau P et al: Duodenal switch: long-term results. Obes
Surg 17:1421, 2007; Mokdad AH et al: Actual causes of death in the United States, 2000. JAMA 291:1238, 2004;
Orlando R 3rd et al: The abdominal compartment syndrome. Arch Surg 139:415, 2004; Ponce J et al: Laparoscopic
adjustable gastric banding: 1,014 consecutive cases. J Am Coll Surg 201:529, 2005; Ren CJ et al: Early results
of laparoscopic biliopancreatic diversion with duodenal switch: a case series of 40 consecutive patients. Obes
Surg 10:514, 2000; Shikora SA: Implantable gastric stimulation for weight loss. J Gastrointest Surg 8:408, 2004;
Sjöström L et al: Swedish Obese Subjects Study. Effects of bariatric surgery on mortality in Swedish obese subjects.
N Engl J Med 357:741, 2007; Sugerman HJ et al: A randomized prospective trial of gastric bypass versus
vertical banded gastroplasty for morbid obesity and their effects on sweets versus non-sweets eaters. Ann Surg
205:613, 1987.
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