Adipocytes, Obesity, Bariatric Surgery and its Complications Daniel C. Morris, MD, FACEP, FAHA Senior Staff Physician Department of Emergency Medicine
Objectives Basic science of adipocyte Adipocyte tissue as an endocrine organ Inflammatory response of obesity Types of bariatric surgery Complications and treatments
Not enough calories out. Too many calories in.
Morbidity and Mortality Type 2 diabetes Hypertension Cardiovascular and Kidney disease Bone and Joint problems Increased risk of Cancer
Gene-Environment
Adipocyte The classic function of the adipocyte is to store and release lipid fuel. Adipocytes can vary in size from 20 to 200 µm. Adipose tissue can be divided into brown and white. Brown adipose tissue is thermogenic whereas white adipose tissue is primarily for storage. Adipose deposits can be intracellular, interorgan and subcutaneous.
Adipocyte Approximately 90% of the adipocyte is triglyceride storage. The remaining 10% consists of nucleus, cytoplasm, mitochondria and other organelles. Hyperplastic obesity Hypertrophic obesity
Classification of obesity Hyperplastic Morphology Hypertrophic Morphology increase in adipocytes increase in adipocyte size juvenile onset obesity adult onset obesity Adipocytes are increased in number rather than in size. The number of cells can never be reduced making it difficult to reduce body fat. Critical times are: last trimester of mother's pregnancy Adipocyte size increases when lipid storage exceeds oxidation release. Hyperplastic obesity can be reduced by increasing activity or by reducing food intake. first year of life puberty
Basic Science of Adipose Tissue: Fat is an endocrine organ In 1994, Leptin was found to originate from the adipocyte. Since then, over three dozen biochemical products have been found in the adipocyte. With the combination of specific receptors and production of endocrine and steriodogenic enzymes, the adipocyte performs specific functions in metabolism.
Adipose tissue obesity sets up a chronic inflammatory response
Mechanism of chronic inflammation
Obesity alters the production and secretion of adipokines Anti-inflammatory Pro-inflammatory
Release of pro-inflammatory adipokines results in atherosclerosis
Adiponectin (protective)
Leptin (inflammatory) Leptin enters the hypothalamus Activates the immune system
Leptin Mutation
Interleukin 6 (IL-6) and Tissue Necrosis Factor (TNF) Adipokine IL-6 Insulin resistance Visceral adipose tissue releases IL-6 directly into the portal system Adipokine TNF Development of type 2 diabetes Insulin resistance
Evolutionary Advantage? Quickly store excess calories Sedentary lifestyle? Immune system is confused by modern diet (pathological diet?) and activity levels Metabolic disease is caused by lipids that are stored in the wrong areas.
Overproduction of adipokines have wide systematic implications in overall health of the individual
Definition of Obesity Body Mass Index (BMI) Waist Circumference Distribution of adipose tissue is the most important determinant of health and disease
Treatment of Obesity Diet and exercise Pharmacologic management- Inadequate long-term clinical efficacy or unacceptable side effects (anal leakage?) Bariatric Surgery- intervention that consistently induces sustained weight loss
Bariatric Surgery Roux-en-Y gastric bypass (common) Sleeve gastrectomy (common) Laparoscopic adjustable gastric band (uncommon) Biliopancreatic diversion with duodenal switch (rare)
Indications for Bariatric Surgery BMI > 40 kg/m² without comorbid conditions BMI between 35 kg/m² and 40 kg/m² with significant comorbidity (diabetes, HTN, apnea) Candidates must have tried and failed nonsurgical weight loss measures
Mechanisms of Weight Loss Stabilizes glucose levels Increases metabolism Behavioral changes in eating habits through alteration of gastro- and neuro- peptides Alteration of gut microbes suggesting that metabolic regulation begins in the gut. Weight loss is not necessary due to smaller stomach
Roux-en-Y gastric bypass
Roux-en-Y Gastric Bypass Common procedure. Restrictive and malabsorptive. Reduces the amount of food ingested. Bypasses a segment of the small bowel leading to incomplete digestion. Produce and maintain excess weight loss of 60% to 80% at 5 years. Procedure can be performed both open or by laparoscope.
Early Major Complications Anastomotic leak with abscess: first few weeks presenting with fever and tachycardia. Incidence in Michigan < 1%. Common site is the gastrojejunostomy. Intra-abdominal or intraluminal bleeding: occurs at the staple lines. Diagnosis is confirmed by endoscope and most bleeding is treated nonoperatively. DVT or pulmonary embolism.
Abdominal Examination Commonly unrevealing even with significant pathology. Obstruction in the bypassed segment will produce vague symptoms. Acute Abdominal Series will show no air fluid levels and is of limited use. CT abdominal is test of choice Patients can sip contrast over 3 hours (230-300 ml). Deteriorate rapidly so early consultation is preferred.
Transverse CT images show normal postoperative anatomy in the gastrointestinal tract, including (a) a small gastric pouch (solid arrow) and gastric staple line (open arrow) Yu J et al. Radiology 2004;231:753-760 2004 by Radiological Society of North America
Leak from gastrojejunal anastomosis in a 41-year-old woman 9 days after gastric bypass surgery. Yu J et al. Radiology 2004;231:753-760 2004 by Radiological Society of North America
Edema at the jejunojejunal anastomosis with resultant reflux of oral contrast material into the excluded stomach in a 52-year-old woman 4 days after gastric bypass surgery. Yu J et al. Radiology 2004;231:753-760 2004 by Radiological Society of North America
Decompression performed with a percutaneous 8-F pigtail catheter Yu J et al. Radiology 2004;231:753-760 2004 by Radiological Society of North America
Late Complications: Anatomic and Systemic Anatomic: bowel obstruction, adhesions, strictures or internal hernias. Progressive inability to tolerate solids or liquids. Anastomotic strictures can be managed endoscopically with balloon dilatation.
Small-bowel obstruction caused by stenosis of the jejunojejunal anastomosis in a 27- year-old woman 10 days after gastric bypass surgery. Dilated proximal efferent loop of small bowel (arrow) Yu J et al. Radiology 2004;231:753-760 2004 by Radiological Society of North America
36-year-old woman with dysphasia after gastric bypass surgery. Jha S et al. AJR 2006;186:1090-1093 2006 by American Roentgen Ray Society
29-year-old woman with epigastric pain after gastric bypass surgery. Jha S et al. AJR 2006;186:1090-1093 2006 by American Roentgen Ray Society
Internal Hernia: Mesocolic defect results in protrusion of multiple loops of small bowel resulting in obstruction.
Internal Hernias-Symptoms Intermittent, crampy, epigastic abdominal pain that radiates to the back. Normal examination 20% will have normal CT scans and/or normal labs. Other CT scans will show the swirl sign (twisting of the mesentery) or obstruction.
Transmesocolonic internal hernia in a 50-year-old woman 3 months after gastric bypass surgery. Yu J et al. Radiology 2004;231:753-760 2004 by Radiological Society of North America
Systemic Late Complications Nutritional deficiencies: Iron, Wernicke s (B1), vitamin B12, Vitamin D and calcium. Secondary hyperparathyroidism: increased bone turnover and decreased bone density. Malabsorption of vitamin D leads to reduced calcium absorption by the intestine leading to hypocalcaemia and increased parathyroid hormone secretion.
Sleeve gastrectomy
Sleeve gastrectomy Equal with bypass. Restrictive and resective. Longitudinal gastric resection, initially performed as a treatment for peptic ulcer disease. Creates a gastric tube by resecting the greater curvature of the stomach. Performed open or by laparoscope. Less risk of nutritional deficiencies. Weight loss ranged from 33 to 85%. Lower rate of resolution of diabetes mellitus and hypertension.
Early Complications Gastric Leak: occurs at staple lines at the angle of His and requires external drainage or endoscopic stent placement. Intra-abdominal bleeding: occurs at the staple lines. Diagnosis is confirmed by endoscope and most bleeding is treated nonoperatively. DVT or pulmonary embolism.
Late Complications Bowel obstruction and adhesions. Rare with laparoscopically performed procedures. Gastroesophageal reflux disease (GERD): is temporary and is gone by 3 months. Most GERD is related to undiagnosed hiatal hernia. Surgeons explore for hiatal hernia and repair at surgery.
Comparison of Bypass and Sleeve Sleeve Gastrectomy has improved safety profile compared to Bypass. Lower rate of resolution of diabetes mellitus and hypertension. Mean excess weight loss approaches that of bypass
Laparoscopic adjustable gastric band
Laparoscopic adjustable gastric band LAP-BAND (INAMED Health, Santa Barbara, CA) Adjustable silastic band that is positioned around the upper portion of the stomach to create a 30 cc pouch. The port allows the band to be tightened or loosened. Regulate the degree of restriction postoperatively, easily reversed. Outpatient surgery. Purely restrictive option.
Complications Early: vomiting as a result of edema or proximal movement of the band. Late: Migration or slippage of the stomach resulting in gastric dilatation. Gastric necrosis or perforation. Deflation of the band can prevent obstruction. Late: Gastric erosion occurs when band erodes the stomach wall. Presents with sepsis, abscess or fistulas. Infection of the port site or device malfunction.
Comparison of Bypass and Band Banding produces much less weight loss compared to bypass (40.4% versus 74.6%). Better efficacy in patients <40 years and BMI <50 kg/m². Mechanical complications. Patients prefer the device as the procedure is outpatient. Fewer metabolic derangements and lower mortality. Long term outcomes show band device complications and inadequate weight loss requiring removal of the device (30%).
Biliopancreatic diversion with duodenal switch
Biliopancreatic diversion with duodenal switch Technically complex procedure. Both restrictive and malabsorptive option. Allows for a large amount of weight loss while preventing the development of the dumping syndrome. Decreasing the size of the stomach and bypassing the duodenum.
Complications Anastomotic leak with abscess. Intra-abdominal bleeding DVT or pulmonary embolism. Bowel obstruction, adhesions, strictures or internal hernias. Nutritional deficiencies: Iron, Wernicke s (B1), vitamin B12, Vitamin D and calcium. Fat-soluble-vitamin deficiencies. Selenium and zinc deficiencies. Hepatic dysfunction leading to jaundice and failure.
Summary
Conclusions Obesity is a multifactorial disease with metabolic consequences. Adipocyte tissue (Fat) is an endocrine organ Adipocytes have a limited lipid storage ability; exceeding that limit sets up an inflammatory response. Bariatric surgery, specifically gastric bypass, is an efficacious treatment for morbid obesity Complications are common and can be lifethreatening.
Conclusions High suspicion for complications when bariatric surgery patients present to the ED. Early complications are obstruction, leaks, bleeding and PE. Late complications are internal hernias, band slips, erosions and strictures. Eat your fruit and vegetables.