Weighty Surgical Issues

Educational Objectives

The goal of this program is to improve management of bariatric surgery. After hearing and assimilating this program, the clinician will be better able to:

1.   Manage a patient in whom cirrhosis is discovered at the time of surgery.

2.   Recognize the contraindications to surgery when a patient is known to have cirrhosis, and determine when to abort surgery in patients with portal hypertension.

3.   Describe the nutritional management of patients undergoing bariatric surgery.

4.   Explain the theory behind neuromodulation as an alternative to bariatric surgery, and list its pros and cons.

5.   Determine whether a patient receiving dialysis is a candidate for bariatric surgery, and choose the best proce­dure for that patient.

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. Shikora is a consultant for Enteromedics and BetaStim; Dr. Schweitzer has received grants from Davol, Enteromedics, and US Surgical, and is a consultant for US Surgical. Drs. Shikora and Schweitzer also present infor­mation in their lectures that is related to off-label or investigative use of a therapy, product, or device. Drs. Sarr, Blackburn, and Pryor and the planning committee reported nothing to disclose.

Acknowledgements

This program was recorded at Surgery of the Foregut 2009, held February 15-18, 2009, in Weston, FL, and sponsored by the Section of Minimally Invasive Surgery and the Bariatric Institute of Cleveland Clinic, FL, 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 in Patients with Liver Cirrhosis

Michael G. Sarr, MD, James C. Masson Professor of Surgery, and Chair, Division of General and Gastroenter­ologic Surgery, Mayo Medical School and Clinics, Rochester, MN

Unexpected cirrhosis discovered at surgery: 1% of cases; bariatric surgery still safe; stipulations  —  malabsorptive procedure may be dangerous because cirrhosis affects liver’s synthetic function; weight loss may reverse cirrhosis induced by steatohepatitis

Choice of surgery: Roux-en-Y gastric bypass  —  can make stomach difficult to intubate in event of variceal bleeding; duodenal switch with biliary-pancreatic diversion (sleeve gastrectomy)  —permits access to gastric remnant, but creates malabsorption; lap band —  option for otherwise healthy patient

Portal hypertension: abort procedure if patient has ascites, varices, or dilated perigastric veins; bleeding risk too high with ascites; dilated perigastric veins with no ascites or obvious varices  —  “probably best to abort the proce­dure”; measure portal pressure through any mesenteric vein along stomach; subtract central venous pressure from portal pressure to obtain corrected portal pressure and transhepatic portal gradient; procedure safe if gradient <10 mm Hg (mild to moderate portal hypertension); abort if gradient >10 to 12 mm Hg

Preoperative cirrhosis: poor hepatic synthetic function contraindication for surgery; if hepatic function normal, pro­ceed with work-up, and consider bariatric procedure (with hope that weight loss will reverse steatohepatitis and cir­rhosis will resolve); decompensated hepatic function  —  may be exacerbated by obesity; decide whether to perform transplantation or bariatric procedure first; if bariatric first, speaker selects nonmalabsorptive procedure but evalu­ates portal hypertension; if patient has varices or portal gastropathy, speaker orders computed tomography (CT); contraindications to surgery  — ascites, markedly dilated spleen, or obvious gastric varices on CT; in absense of contraindications, obtain corrected portal pressure; sleeve gastrectomy or gastric band appropriate if portal hyper­tension mild to moderate; gastric bypass sometimes possible in these cases; any perigastric or gastric procedure too dangerous for patients with severe portal hypertension

Choice of procedure according to corrected portal pressure: mild portal hypertension (<8 mm Hg)  —  sleeve gas­trectomy; moderate hypertension (8-10 mm Hg)  —  sleeve gastrectomy; these patients often require liver transplan­tation; gastric bypass interferes with options for transplantation; lap band possibility if esophagogastric junction appears intact; severe hypertension (>12 mm Hg)  —  if synthetic function still good, consider placing transjugular intrahepatic portosystemic shunt to lower portal pressure, then perform bariatric procedure (sleeve gastrectomy), with hope that weight loss will reverse or stabilize cirrhosis

Nutritional Aspects in Bariatric Patients

George L. Blackburn, MD, PhD, S. Daniel Abraham Chair in Nutrition Medicine, Harvard Medical School, and Director, Center for the Study of Nutrition Medicine, Beth Israel Deaconess Medical Center, Boston, MA

Caloric requirements: assume 10 cal per pound of body weight for resting metabolic rate; another 5 cal per pound for activities of daily living (may vary by +10%); carrying excess weight also requires more calories; 20% weight loss means patient needs 500 fewer calories per day

Energy balance: energy intake only independent variable that significantly affects weight; in one study, patients who lost <10% of their body weight after surgery did not eat less, did not exercise, did not eat healthier foods, main­tained a stressful lifestyle, and did not get adequate sleep; behavioral program necessary to change these habits

Preoperative weight loss program: for 2 wk, patient has 3 meal replacements per day, plus one 450-cal meal (lean protein, fruits, vegetables, and limited starch); goals are weight loss and nutrition education

Postoperative diet: stage 1  —  water; stage 2  —  clear liquids; stage 3  —  low-sugar, high-protein full liquids (600-800 cal/day); stage 4  —  soft solid foods (ground or pureed; 800-1000 cal/day); stage 5  —  lean protein, fresh fruits and vegetables, whole grains, and healthy fats (lifetime diet, 1400-1600 cal/day [men] or 1000-1200 cal/day [women]); patients who eat more risk gaining weight

Objectives: hydration (most important); adequate intake of protein, vitamins, and minerals to support homeostasis and adequate wound healing, maximize fat loss and minimize lean tissue loss, facilitate safe sustained weight loss, and nurture healthy lifestyle

Lifetime diet: “real food,” with emphasis on protein and hydration; satiety-inducing or “anti-obesity” foods; texture important; patient must develop tolerance for eating to prevent dumping syndrome; if patient gets to stage 3 or 4 and starts vomiting, revert to stage 2 (ie, clear liquids); protein  —moist fish, egg whites, low-fat dairy products, or soy; introduce protein first to avoid dumping syndrome; patient should be at stage 3 by time of hospital dis­charge; start with 60 to 80 g of protein per day, going to 1 to 1.5 g per kilo of ideal body weight (25%-30% of to­tal daily calories); carbohydrates  —  low-fat dairy products, nonstarchy vegetables, legumes, whole grains, and fruits; limit white starchy foods; avoid processed foods and simple sugars; carbohydrates should account for 40% to 50% of total daily calories; fat  —  limit quantities; 20% to 30% of calories; hydration critical; postoperative weakness and fatigue often due to dehydration, rather than to lack of food; stage 5 diet  —  high-protein; 40% to 50% of calories from complex carbohydrates; low in fat; no more than 5 hr should elapse between meals; chew food until it is liquid

Patient support: online programs answer questions, provide reminders, and offer nutritional guidance

Neuromodulation for Diabetes
and Weight Loss/Vagal Block

Scott A. Shikora, MD, Professor of Surgery, Tufts University School of Medicine, Boston, MA

Neuromodulation: potential alternative to bariatric surgery; involves application of patterned electric current to tar­get organ can be programmed to stimulate or block normal physiologic response; stimulation  —  low-frequency current sent antegrade and retrograde; blocking  —  higher-frequency current halts activity of targeted organ

Potential benefits: fewer risks than bariatric surgery; may eliminate associated nutritional problems and need for monitoring; patients may be able to eat more normally

Techniques under investigation: blockage or stimulation of vagus nerve, sympathetic nervous system, or stomach itself; endoscopic as well as laparoscopic approaches being studied; currently, intestine most effective site

Implantable gastric stimulator (IGS): sends constant small patterned electric current to gastric serosa near vagus nerve; outpatient procedure; takes <1 hr; involves no alteration of gastrointestinal (GI) tract; not associated with any significant physiologic changes; safe, adjustable, and easily reversible; performed on 800 patients to date, with no deaths, leaks, or major complications; earliest patients followed for 10 yr; among patients who respond, mean excess weight loss 35%; main problem  —  low response rate, probably due to inadequate study of mecha­nism of action

Meal-activated gastric stimulation (Tantalus system): remains dormant until patient eats; consists of 6 leads (2 in fundus [sensing leads] and 4 in distal antrum [effector leads]); to date, 2 small open-label trials have yielded promising results (however, 3 in 12 patients did not respond)

Vagus nerve systems: 80% of vagal fibers carry signals from GI tract to brain; some evidence that patients undergo­ing vagal stimulation to treat epilepsy also lose weight; vagal blocking for obesity control (VBLOC) system in­volves implantation of electrodes on vagus nerve trunks at gastroesophageal junction; electrical impulses block vagal output; system active 14 hr/day; results of small  pilot studies promising, with no serious side effects seen; speaker now participating in multicenter trial involving 300 patients

Duodenal stimulation to treat diabetes: similar to gastric stimulating systems; involves pulse generator, leads, and target organ (proximal duodenum, just beyond pylorus); human studies under way; data from animal studies show no change in pancreatic function; duodenal stimulation delays gastric emptying and increases duodenal flow, with subsequent decrease in intestinal transit time; causes malabsorption of sugars and fats present (in stool); decreases serum glucose and insulin levels; effect on weight still unknown

Transoral Revision of Gastric Bypass

Michael Schweitzer, MD, Associate Professor of Surgery, Johns Hopkins University School of Medicine, Balti­more, MD

Weight gain after bariatric surgery: primarily due to resumption of poor eating habits; may involve dopamine re­ceptors; role of stoma or gastric pouch dilation questionable

Primary issues with suturing devices: safety (risk for esophageal perforation); tissue depth; flexibility; equipment requirements; type and strength of suture; formation of knots

Needle types: straight, curved, or hollow

Methods of grasping tissue: suction problematic, due to tissue depth; also difficult to see tissue grasped; difficult to adjust depth or determine amount of tissue grasped; helical screws or graspers other possibilities

Knots: most surgeons today using crimping device; T-fasteners and pledgeted sutures also widely used

Devices

Endoscopic Suturing Device (Wilson-Cook): taped to endoscope; difficult to use in actual practice; requires >1 su­ture

EndoCinch Suturing System (Bard): has reusable handle and suturing capsule that fits onto end of endoscope; how­ever, device “picky” (eg, will not fit onto endoscope that has been repaired, may be frustrating to use); uses suc­tion to grasp tissue; depth varies, so may not obtain enough “bite”; ineffective if pouch 10 x 10 cm, and difficult to use if pouch <2 cm; sutures must be pulled up from stoma and out through mouth; reduce stoma to 5 to 8 mm; considered “old technology”

Full-Thickness Plicator (NDO Surgical [no longer in business]): does not fit into most pouches

Spiderman Endoscopic Suturing Device (Ethicon): under development; places purse-string suture around stoma

Flexible Endostitch Suturing Device (US Surgical): best application not yet determined

StomaphyX (EndoGastric Solutions): easy to use; employs suction; uses prolene plicators to reduce pouch and stoma size; Food and Drug Administration (FDA) – sanctioned trial never conducted, so insurance companies will not approve; recently approved by FDA for use in GI tract; keep sclerosing needle nearby to control bleeding; helpful to have advanced endoscopy experience

g-Prox Tissue Grasper/Approximation Device (USGI Medical): uses suture anchors; expensive (³$3000); in United States, entire procedure could cost $10,000 to $13,000; does not work in enlarged pouch; can be used to close false diverticuli and gastrocutaneous fistulae

Transplantation, Renal Failure,
and Bariatric Surgery

Aurora Pryor, MD, Associate Professor of Surgery, Duke University School of Medicine, Durham, NC

End-stage renal disease (ESRD) and morbid obesity: 300,000 patients currently on hemodialysis; »8% have body mass index (BMI) >35; >100,000 patients with ESRD waiting for renal transplantation; organs scarce, so alloca­tion partially based on projected outcome

Factors that influence kidney allocation: patient’s age, cause and duration of renal failure, overall nutritional status, BMI, ethnicity, and comorbidities; odds of morbidly obese patient being organ recipient approximately one-half those of normal-weight patient; obese person more likely to be disregarded when organ becomes available; weight loss may increase chances of receiving organ or diminish some of conditions associated with renal failure (eg, hypertension, diabetes)

Effect of obesity: at many centers, patients with BMI >35 excluded from transplantation; associated with doubling of normal risk for cardiac events, reduced life expectancy, higher risk for wound infection, increased operating time, and higher risk for delayed graft rejection or posttransplantation diabetes

Bariatric procedures: adjustable gastric band  —  low perioperative risk, but associated with less weight loss than other procedures; patient may not achieve enough weight loss for transplantation; also introduces foreign body, which may present risk if patient takes immunosuppressive medications; may complicate peritoneal dialysis; lack of malabsorption is advantage; Roux-en-Y gastric bypass  —  perioperative risk moderate; overall weight loss good; no foreign body involved; bowel anastomosis may create risk for peritonitis in patient on peritoneal dialy­sis; consider providing peri-operative access to hemodialysis for such patients; sleeve gastrectomy  — perioperative risk moderate and overall weight loss reasonable; does not involve foreign body, but, like bypass, may introduce risk for peritonitis in patients on peritoneal dialysis; does not involve malabsorption; biliary-pan­creatic diversion and duodenal switching  —  in general, not good choices for patients with ESRD

Data to support bariatric procedures in this population: limited; small studies show good outcomes, but effect on transplantation outcomes unknown

Effect on dialysis patients: resolution of comorbidities (eg, improved blood pressure, better lipid profile, resolution of diabetes) similar to that observed in patients not on dialysis, with stable serum albumin

Preoperative considerations: elevated cardiovascular risk (patients should undergo intensive cardiology work-up); nutritional status; placement of hemodialysis access

Contraindications: renal failure, coagulopathy, severe cardiac disease, and impaired clotting

Possible complications: change in drug dose or metabolism; increased risk for reaction to immunosuppression

Suggested Reading

Abeles D, Shikora SA: Bariatric surgery: current concepts and future directions. Aesthet Surg 28:79, 2008; Blackburn GL, Mun EC: Therapy insight: weight-loss surgery and major cardiovascular risk factors. Nat Clin Pract Cardiovasc Med 2:585, 2005; Chin PL et al: Adjustable gastric band placed around gastric bypass pouch as revision operation for failed gastric bypass. Surg Obes Relat Dis 5:38, 2009; Cigaina V: Long-term follow-up of gastric stimulation for obesity: the Mestre 8-year experience. Obes Surg 14 Suppl 1:S14, 2004; de Andrade AR et al: Nonalcoholic fatty liver disease in severely obese individuals: the influence of bariatric surgery. Ann Hepatol 7:364, 2008; Koshy AN et al: Laparoscopic gastric banding surgery performed in obese dialysis patients prior to kidney transplantation. Am J Kidney Dis 52:e15, 2008; Olarte IG et al: Kidney transplant complications and obesity. Am J Surg 197:424, 2009; Sarr MG: Is a bariatric procedure appropriate in patients with portal hypertension secondary to cirrhosis? Surg Obes Relat Dis 2:405, 2006; Shi­kora SA et al: Implantable gastric stimulation for the treatment of clinically severe obesity: results of the SHAPE trial. Surg Obes Relat Dis 5:31, 2009; Shikora SA et al: Nutrition and gastrointestinal complications of bariatric surgery. Nutr Clin Pract 22:29, 2007; Shikora SA: Implantable Gastric Stimulation – the surgical procedure: combining safety with simplicity. Obes Surg 14 Suppl 1:S9, 2004; Topart P et al: One-year weight loss after primary or revisional Roux-en-Y gastric bypass for failed adjustable gastric banding. Surg Obes Relat Dis. 2008 Aug 19 [Epub ahead of print].