gastric bypass surgery; Roux-en-Y gastric bypass

Introduction

Also see bariatric surgery.

Indications

• morbid obesity; BMI > 40
• BMI > 35 with serious obesity-related comorbidities

Laboratory

• twice a year for the first 2 years after gastric bypass, then yearly laboratory tesing consisting of:
  • serum vitamin B12
  • serum ferritin
  • serum folate
  • serum calcium
  • serum 25-OH vitamin D

* also see ARUP consult

Procedure

• combines gastric restriction with diminished absorption
• stapling the cardia of the stomach creates a 20-30 mL pouch; ref suggests pouch size of 7-10 mL
• the jejunum is divided distal to the ligament of Treitz with the distal end anastomosed to the upper stomach; duodenum & lower part of stomach bypassed
• hospital stay typically 3-4 days

Complications

• complications 15%
• abdominal pain is the most common post-operative complication
• 30 day major complications 5% (venous thromboembolism)
• 30 day mortality 0.5%
• stomal stenosis (manifested by nausea/vomiting)
• cholelithiasis
• nephrolithiasis; calcium oxalate stones
• stricture or ulceration
• dumping syndrome
• intestinal bacterial overgrowth
  • trial of empiric antibiotics
• increased risk of suicide; overall rate low
• nuritional deficiency
  • vitamin A deficiency in 10-50% & up to 61-69% with bilio- pancreatic diversion
  • vitamin B12 deficiency due to lack of intrinsic factor
  • folate deficiency, vitamin D deficiency, calcium deficiency, iron deficiency, copper deficiency
  • other vitamin deficiencies including thiamine deficiency, pyridoxine deficiency, vitamin C deficiency, vitamin E deficiency, vitamin K deficiency, selenium deficiency & zinc deficiency less common

Management

• patients must consume < 800 kcal/day for 1st 12-18 months
• diet 1000-1200 kcal/day (after 1st 12-18 months) in 3 small high-protein meals 3 times/day
• avoid sugar, refined carbohydrates & fats to prevent dumping syndrome
  • avoiding refined carbohydrates more important than low-fat diet
• trial of emipiric antibiotics for intestinal bacterial overgrowth
• revision & reoperation much lower than for gastric banding (0.3% vs 17%)

Notes

• superior to gastric banding, but more complications
  • twice as much weight loss as laparoscopic gastric banding, at the cost of more short-term complications & long-term hospitalizations
• sleeve gastrectomy more common than gastric bypass
• 60-70% excess weight loss;
  • 35 kg vs 0-3 kg without surgery after 12 years in morbidly obese
• improvement in left ventricular hypertrophy
• GERD symptoms resolve in 63% of patients (contrast with sleeve gastrectomy)
• sustained benefits at 6 years, 10 years; 12 years
  • weight reduction (32% vs 16% for gastric banding)
  • diminished risk of type 2 diabetes
    • 3% vs 26% without surgery after 12 years in morbidly obese
    • 2/3 of patients with diabetes mellitus type 2 sustain at least partial remission (vs 1/4 for gastric banding)
  • diminished risk of hypertension
  • diminished risk of lipodystrophy
  • improvements in dyslipidemia similar to gastric banding
• 5-year diabetes remission rate somewhat higher for gastric bypass than sleeve gastrectomy
• more weight loss with gastric bypass vs sleeve gastrectomy or adjustable gastric banding
  • 30 day complications (reoperation, venous thromboembolism) more frwquent 5% vs < 3% for other procedures
• Roux-en-Y gastric bypass achieves a greater excess BMI loss at 10 years vs laparoscopic sleeve gastrectomy
  • GERD is better treated by gastric bypass

More general terms

• bariatric surgery
• surgical anastomosis

More specific terms

• esophagocolic anastomosis; esophagocolostomy
• esophagojejunostomy