Obesity Surgery

Aka: Obesity Surgery, Roux-en-Y gastric bypass, Roux-en-Y Bypass, Roux-en-Y Anastomosis, Roux-en-Y Intestino-Biliary Bypass, Jejunoileal Bypass, Gastric Sleeve, Sleeve Gastrectomy, Laparoscopic Sleeve Gastrectomy, Vertical Banded Gastroplasty, Distal Gastric Bypass, Biliopancreatic Diversion, Gastric Bypass, Gastroplasty, Bariatric Surgery, Metabolic Surgery

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II. Epidemiology

  1. Incidence
    1. In 2013 US: 179,000 bariatric surgeries were performed (42% Gastric Sleeve and 34% Roux-en-Y Bypass)
    2. In 2017 US: 228,00 bariatric surgeries were performed (60% Gastric Sleeve, 18% Roux-en-Y Bypass)
    3. In 2019, U.S. 256,000 bariatric surgeries were performed (60% Gastric Sleeve, 18% Roux-en-Y Bypass)

III. Indications: Obesity

  1. Indications vary depending on organizations (e.g. ACC/AHA, ASMBS, IFSO, AACE/ACE...)
  2. Body Mass Index (BMI) >= 40 kg/m2 (Class 3 Obesity)
  3. Body Mass Index (BMI) >= 35 kg/m2 (Class 2 Obesity) with Obesity-related severe comorbidity
    1. Primary comorbidity indications
      1. Type II Diabetes Mellitus or Prediabetes
      2. Obstructive Sleep Apnea
      3. Cardiomyopathy
      4. Nonalcoholic Fatty Liver Disease (NASH)
      5. Debilitating Lower Extremity Arthritis (e.g. Osteoarthritis of the hip or knee)
      6. Hypertension
      7. Hyperlipidemia
      8. Urinary Stress Incontinence
    2. Other conditions for which the procedure may be considered
      1. Obesity Hypoventilation Syndrome
      2. Idiopathic Intracranial Hypertension
      3. Refractory Gastroesophageal Reflux disease
      4. Severe Venous Stasis
      5. Obesity-related impaired mobility
      6. Significantly impaired quality of life
  4. Body Mass Index (BMI) >= 30 kg/m2 (Class 1 Obesity)
    1. Diabetes Mellitus with inadequate glycemic control despite optimal lifestyle and medical management
  5. Body Mass Index (BMI) >= 27.5 kg/m2
    1. Asian descent
  6. Body Mass Index (BMI) >=25 kg/m2
    1. Asian descent AND type 2 diabetes or refractory to nonsurgical management

IV. Contraindications

  1. High risk cardiopulmonary disease
  2. Ongoing Drug Abuse, Alcohol Abuse or other uncontrolled mental health disorder
  3. Reversible pathologic causes of Obesity (e.g. endocrine disorder)
  4. Poor insight into the risks, benefits, lifestyle investment, alternative options, or expected outcomes

V. Mechanism

  1. Bariatric Surgery results in decreased sense of hunger, increased satiety and increased glycemic control
  2. Mechanisms go beyond restrictive (small Stomach) and malabsorption (small intestinal bypass) models
  3. Neuroendocrine responses to Bariatric Surgery play a key role in energy homeostasis
    1. Glucagon-Like Peptide 1 (GLP-1) increases Insulin secretion
    2. Peptide YY increases satiety and delays gastric emptying
    3. Insulin, gherlin, Leptin, c-rp, Interleukin-6, TNF-alpha and adiponectin are all affected by Bariatric Surgery

VI. Procedures: Common

  1. Images
    1. bariatricSurgery.jpg
  2. Roux-en-Y gastric bypass (RYGB)
    1. Accounted for 34% in 2013 and 18% in 2017 of Bariatric Surgery procedures in U.S.
    2. Gold standard method today
    3. Description
      1. Stomach partitioned into 20-60 ml pouch
      2. Pouch anastomosed to jejunum
      3. Remainder of Stomach and duodenum bypassed
        1. Intestine is bisected at ~100 cm from the pylorus
    4. Efficacy
      1. Weight loss >48% at 1-2 years, >53% at 3-6 years and >25% at 7-10 years
      2. Diabetes Mellitus remission occurs in 46-81% at 1-3 years
    5. Safety
      1. Perioperative mortality: 0.2 to 0.5% within 30 days (0.14 to 0.21% at >30 days)
      2. Mortality is reduced 30-50% compared to those who did not undergo surgery
    6. Disadvantages
      1. Malabsorption of iron, B12 and Calcium
      2. Technically difficult with higher morbidity
  3. Gastric Sleeve or Laparoscopic Sleeve Gastrectomy (introduced in 2008)
    1. Accounted for 42% in 2013 and 60% in 2017 and 2019 of Bariatric Surgery procedures in U.S. (most common)
    2. Description
      1. Lateral Stomach excised leaving a smaller, narrow, tubular residual Stomach pouch
      2. Promising procedure introduced in 2008 with high efficacy
      3. Lower adverse effects (e.g. no dumping)
      4. May be used to bridge super-obese patients (BMI>50) to ultimately have Roux-en-Y gastric bypass
    3. Efficacy
      1. Weight loss >33% at 1-2 years and >46% at 3-6 years
      2. Diabetes Mellitus remission occurs in 80% at 1-3 years
    4. Safety
      1. Perioperative mortality: 0.296% within 30 days (0.11 to 0.34% at >30 days)
      2. Mortality is reduced 30-50% compared to those who did not undergo surgery
  4. Single Anastomosis Duodenal-Ileal Bypass with Sleeve (approved 2020)
    1. Description
      1. Combines Gastric Sleeve (as above) with bypass of the duodenum
      2. Proximal duodenum is anastomosed to the ileum (bypassing the duodenum and biliopancreatic limb)
      3. Performed at the same time of Gastric Sleeve or as a revision to prior Gastric Sleeve procedure
  5. Laparoscopic Adjustable Gastric Banding (introduced in 2006)
    1. Accounted for 14% in 2013 and <1% in 2019 of Bariatric Surgery procedures in U.S. (falling out of favor)
    2. Description
      1. Band applied around the distal Esophagus or proximal Stomache
      2. Reversible and tension can be adjusted via subcutaneous port
      3. Replaces Vertical Banded Gastroplasty
    3. Efficacy
      1. Weight loss >29% at 1-2 years, >39% at 3-6 years and >14% at 7-10 years
      2. Diabetes Mellitus remission occurs in 28% at 1-3 years
    4. Safety
      1. Perioperative mortality: 0.02 to 0.07% within 30 days (0.21 to 0.50% at >30 days)
  6. Surgical Revisions
    1. Bariatric Surgery revision accounted for 6% in 2013 and 14% in 2017 of Bariatric Surgery procedures in U.S.
  7. Resources
    1. Estimate of Bariatric Surgery Numbers 2011-2018 (ASMBS)
      1. https://asmbs.org/resources/estimate-of-bariatric-surgery-numbers

VII. Procedures: Other procedures

  1. Intragastric Balloon
    1. Balloon inserted via endoscopy
    2. Reduces Stomach size after inflation
    3. Left in place for 6 months
  2. Biliopancreatic Diversion (introduced in 2004)
    1. Very effective in super-obese patients (BMI>50 kg/m)
    2. Weight loss 40% at 1 year and 30-40% at 10 years

VIII. Procedures: Not recommended

  1. These procedures are NOT recommended by NIH panel
    1. Significantly higher risk of complications
  2. Jejunoileal Bypass (Distal Gastric Bypass)
    1. Less commonly performed since 1985 (with a few exceptions)
  3. Vertical Banded Gastroplasty (VBG or Stomach stapling)
    1. Less commonly performed since 1989 due to low long-term efficacy
      1. Replaced by Adjustable Gastric Banding
    2. Efficacy
      1. At 3 years: 40-63% excess Weight Reduction
      2. At 10 years: 20% excess Weight Reduction
    3. Disadvantages
      1. Less effective than Roux-en-Y Procedure
      2. High surgical revision rate (41-45%)
        1. Due to high rate of staple dehiscence
        2. Once staple line opens, weight gain returns
      3. Higher risk of stricture or GERD
    4. Perioperative mortality: 0-1.0%

IX. Evaluation: Postoperative Complications

  1. See specific complications below
  2. Risk Factors for Postoperative Complications
    1. Preoperative BMI >50 kg/m2
    2. Age >55 years old
    3. Male gender
    4. Pulmonary Hypertension
    5. Congestive Heart Failure
    6. Underlying liver disease
  3. High risk presentations
    1. Post-operative Fever (red flag)
    2. Tachycardia (red flag)
    3. Hypotension
    4. Tachypnea or Hypoxia
    5. Bleeding
    6. Vomiting with Abdominal Pain
  4. Approach
    1. Involve bariatric surgeon early in presentation to discuss evaluation and management strategy
    2. CT Abdomen with oral and IV Contrast (often indicated, but beware False Negatives)
      1. When performing CT Abdomen, consider CT Chest for Pulmonary Embolism given similar presentations
      2. Exercise caution with oral Contrast Material due to small proximal pouch
  5. Avoid harmful measures
    1. Avoid NSAIDs, Aspirin, Plavix and other irritative agents
    2. Avoid Nasogastric Tube
      1. Risk of proximal pouch rupture
      2. Ineffective at decompression after most bariatric procedures

X. Complications: Acute Serious Complications

  1. Perioperative Mortality
    1. Procedure Type
      1. Roux-en-Y gastric bypass (RYGB): 0.14 to 0.3% mortality
      2. Sleeve Gastrectomy: 0.08%
      3. Biliopancreatic Diversion (BPD-DS): <0.3% mortality
      4. Laparoscopic Adjustable Gastric Banding (LAGB): 0.03% mortality
    2. Patient factors: Highest risk
      1. Body Mass Index (BMI) over 60 kg/m2: 3% mortality
      2. Age over 60 years: 1% mortality
    3. Patient factors: Additive risks (Mortality increases from 0.2% up to 2.4% if at least 4 criteria are present)
      1. Age over 45 years old
      2. Hypertension
      3. Male gender
      4. Pulmonary Embolism risk (DVT history, Pulmonary Hypertension, Obesity-related hypoventilation)
      5. Body Mass Index >50
  2. Thromboembolic complications
    1. See peri-operative Thromboembolism prophylaxis below
    2. Pulmonary Embolism is the most common cause of mortality following Bariatric Surgery
      1. Post-bariatric surgery Pulmonary Embolism is associated with a 20-30% mortality
    3. Portal Vein Thrombosis
      1. Gastric Sleeve is the most common surgical cause of Portal Vein Thrombosis
      2. Presents 7-10 days post-op with diffuse Abdominal Pain, Nausea, Vomiting, Leukocytosis
      3. Identified on CT Abdomen with contrast
      4. Emergent consult to Bariatric Surgery and Intervention Radiology
      5. Initially treated with Heparin (and in some cases catheter directed or systemic Thrombolytics)
      6. Swaminathan and Shoenberger in Herbert (2020) EM:Rap 20(7):13
  3. Anastomotic Leak (and secondary Sepsis)
    1. Leak at anastomosis or banding site
      1. Roux-en-Y gastric bypass
        1. Gastrojejunal anastomotic leak (high risk)
        2. Jejunojejunal anastomotic leak
      2. Sleeve Gastrectomy
        1. Staple line leak (high risk)
    2. Requires emergency evaluation
    3. Presentation
      1. Sepsis signs may initially be subtle
      2. Severe Abdominal Pain
      3. Fever
      4. Hypotensive shock
      5. Heart Rate over 120 associated with Abdominal Pain increases Specificity
        1. Tachycardia in first 72 hours after Bariatric Surgery should first be considered an anastomotic leak
    4. Evaluation
      1. CT Abdomen with contrast (only 60% sensitive)
        1. Consider CT Chest for Pulmonary Embolism at the same time (especially if Tachycardia is acute presentation)
          1. Anastomotic Leak and Pulmonary Embolism may present in similar fashion
      2. Urgent surgical Consultation
        1. May require exploration despite negative CT Abdomen
        2. Early intervention within first 24 hours improves outcomes
  4. Internal Hernia (occurs in up to 3% of retrocolic bypass procedures)
    1. See Internal Hernia
    2. Obtain CT Abomen with contrast
    3. Requires immediate surgical Consultation
  5. Bleeding
    1. Gastric pouch is the most common bleeding source
      1. Early: Staple Line
      2. Late: Peptic Ulcer
    2. Management
      1. Stabilization as with other Upper Gastrointestinal Bleeding
      2. Hemodynamic instability may occur earlier due to reduced oral intake after Bariatric Surgery
      3. Upper endoscopy
        1. Requires endoscopy operator is skilled at navigating altered anatomy following Bariatric Surgery

XI. Complications: Short-term

  1. Small Bowel Obstruction
    1. Always consider Internal Hernia (see above)
    2. Avoid Nasogastric Tube (see above)
  2. Wound Infection
    1. Occurs up to 3 weeks after surgery
    2. Risk of developing Incisional Hernia
  3. Stomal stenosis
    1. Presentations
      1. Early satiety (more than expected)
      2. Upper Abdominal Pain
      3. Vomiting even with liquid meals
    2. Evaluate Upper gastrointestinal series
    3. Treat with dilatation via upper endoscopy
  4. Peptic Ulcer at surgical anastomosis (marginal ulcer)
    1. Evaluate with upper endoscopy
    2. Avoid NSAIDs
  5. Constipation
    1. Maximize hydration (96 ounces clear fluid daily)
    2. Minimize Narcotic Analgesics post-operatively
    3. Avoid Bulk Laxatives after Gastric banding
      1. Risk of obstruction

XII. Complications: Long-term

  1. Small Bowel Obstruction
    1. See short-term complications and Internal Hernias above
  2. Cholelithiasis or Cholecystitis (30% of patients)
    1. Consider Cholecystectomy at time of Bariatric Surgery
  3. Nephrolithiasis related to Calcium Oxalate Stone formation
  4. Secondary Hyperparathyroidism
  5. Gastroesophageal Reflux Disease
    1. More common with restrictive surgery (Sleeve Gastrectomy, adjustable gastric band)
  6. Malabsorption (Roux-en-Y Bypass, Duodenal Ileal Bypass with sleeve)
    1. See lab monitoring below
    2. See post-operative diet below
    3. Protein-calorie Malnutrition
    4. Lipid and Fat malabsorption (decreased enterohepatic circulation)
    5. Lactose Intolerance
    6. Beef intolerance (due to heightened Sense of Taste and smell)
  7. Vitamin Deficiency (esp. B Vitamins and Fat Soluble Vitamins A, D, E, K)
    1. Calcium malabsorption
    2. Micronutrient deficiency
      1. Copper deficiency
      2. Zinc Deficiency
      3. Selenium Deficiency
    3. Vitamin A Deficiency (night blindness)
    4. Neuropathy related to Deficiency
      1. Vitamins B1 deficiency (Thiamine Deficiency)
      2. Vitamin B12 Deficiency
      3. Vitamin E deficiency
    5. Anemia due to Vitamin Deficiency
      1. Iron Deficiency Anemia
      2. Folate Deficiency
      3. Vitamin B12 Deficiency
  8. Dumping Syndrome (40 to 60% of patients)
    1. May occur early or late following oral intake
      1. Early dumping is associated with rapid nutrient flow into the Small Bowel with Fluid Shifts
        1. Onset within one hour of eating
        2. Symptoms include Abdominal Pain, Diarrhea, bloating and Nausea
        3. May also cause Flushing, Palpitations, sweating, Tachycardia, Hypotension, Syncope
      2. Late dumping is associated with rapid Carbohydrate absorption and exaggerated Insulin response
        1. Results in Reactive Hypoglycemia onset 1 to 3 hours after eating
    2. Management
      1. Eat small frequent meals
      2. Avoid rapidly absorbed sugars (e.g. Simple Sugars)
      3. Avoid fluid with meals
      4. Consider Acarbose (Precose) to slow CarbohydrateDigestion
      5. Consider Somatostatin analog
      6. Surgical revision may be needed in some cases
    3. References
      1. Tack (2014) Best Pract Res Clin Gastroenterol 28(4): 741-9 [PubMed]
  9. Overall body changes
    1. Hair thinning (due to rapid weight loss)
      1. Supplement with more Dietary Protein
      2. Consider Biotin
    2. Metrorrhagia
    3. Fatigue
    4. Fertility increases
      1. Use reliable Contraception to avoid pregnancy within first 2 years after surgery
      2. Food intolerance
        1. Lactose Intolerance
        2. Beef intolerance (due to Hypersensitivity to taste and smell)
  10. Altered medication absorption
    1. Gastric banding (gastric restriction)
      1. Consider switch from XR to immediate release agents
      2. Take one medication at a time
    2. Gastric Bypass
      1. Monitor Digoxin and Levothyroxine dosing closely
      2. Exercise caution when using Azole Antifungals
  11. Bacterial overgrowth
    1. Presents with Abdominal Distention, Proctitis, nighttime Diarrhea, and Arthralgias
  12. Panus (84% of patients)
    1. Results in local skin irritation, Fungal Infections and discomfort during Exercise
    2. Paniculectomy indications
      1. Refractory skin irritation
      2. Panus severe enough to cover genitalia

XIII. Complications: Lap Band

  1. Adhesions with Bowel Obstruction
  2. Port-tubing complications
  3. Infected port-site with overlying Cellulitis
  4. Band prolapse
    1. Presents as A band that is altered from its standard positioning
    2. Band is normally positioned at a 45 degree angle to the spine
  5. Band erosion
    1. Presents as Gastrointestinal Bleeding or Abdominal Pain
    2. Diagnosis with upper endoscopy
  6. Band too tight
    1. May present with pain and Vomiting
    2. Consider gastrograffin upper GI study or CT Abdomen with contrast
    3. Consider band deflation (especially if Vomiting and pain)
      1. Aspirate 4-14 cc fluid from subcutaneous port with a Huber needle

XIV. Efficacy

  1. Bariatric Surgery is associated with substantial weight loss
    1. Average of 57 lbs (26 kg) MORE weight loss than non-surgical management
    2. Total weight loss of 66 to 110 lbs (30 to 50 kg) or 60-70% of excess weight loss (20-30% of total weight)
    3. BMI decreases 11 to 17 kg/m2
    4. Gloy (2013) BMJ 347: f5934 [PubMed]
  2. Bariatric Surgery may cure diabetes in morbid Obesity
    1. Rubino (2002) Ann Surg 236:554-9 [PubMed]
  3. Significantly reduces morbidity and mortality
    1. Diabetes Mellitus 76% resolved or improved (5 times more likely than in non-surgical management)
    2. Total and LDL Cholesterol was significantly reduced
    3. Hypertension resolved in 61% (improved in 78%)
    4. Sleep Apnea resolved or improved in 83%
    5. Mortality over 9 years reduced from 28% to 9% (all cause mortality reduction 29-40% across multiple studies)
    6. Buchwald (2004) JAMA 292:1724-37 [PubMed]

XV. Labs: Monitoring schedule post-procedure

  1. Three months after surgery
    1. Complete Blood Count
    2. Blood Glucose (or Hemoglobin A1C)
    3. Serum Creatinine
  2. Six months after surgery
    1. Complete Blood Count
    2. Blood Glucose (or Hemoglobin A1C)
    3. Serum Creatinine
    4. Serum Calcium
    5. Liver Function Tests
    6. Serum Protein
    7. Serum Albumin
    8. Serum Ferritin
    9. Serum Vitamin B12
    10. Serum Folic Acid
  3. Nine months after surgery
    1. Complete Blood Count
    2. Blood Glucose (or Hemoglobin A1C)
    3. Serum Creatinine
  4. One year after surgery and then every year therafter
    1. Complete Blood Count
    2. Blood Glucose (or Hemoglobin A1C)
    3. Serum Creatinine
    4. Serum Ferritin
    5. Serum Vitamin B12
    6. Serum Vitamin D
    7. Serum Vitamin A
    8. Other labs to consider
      1. Serum Thiamine
      2. Serum Copper
      3. Serum Zinc
      4. Serum Magnesium
      5. Serum Vitamin B6

XVI. Labs: Preoperative evaluation (varies by surgery group protocol)

  1. Comprehensive metabolic panel (renal and hepatic panel)
  2. Complete Blood Count with Platelets
  3. Coagulation studies (INR and PTT)
  4. Hemoglobin A1C
  5. Fasting lipid panel
  6. Thyroid Stimulating Hormone (TSH)
  7. Vitamin D (25-hydroxyvitamin D)
  8. Vitamin B12 (Cyanocobalamin)
  9. Vitamin B9 (Folate)
  10. Vitamin B6 (Pyridoxine)
  11. Vitamin B1 (Thiamine)
  12. Iron Studies (Serum Iron, TIBC, Serum Ferritin)
  13. Urinalysis
  14. Urine Pregnancy Test (in all women of child-bearing age with a Uterus)
  15. Chest XRay
  16. Electrocardiogram
  17. Consider RUQ Ultrasound, upper endoscopy, H. pylori testing

XVII. Management: Pre-operative Evaluation

  1. Preoperative bariatric evaluation is identical to that in non-obese, non-Bariatric Surgery patients
    1. See Preoperative Exam
    2. Exceptions: Obstructive Sleep Apnea and Venous Thromboembolism
    3. Weight loss history and surgery justification is generally completed well before preoperative evaluation
    4. Encourage Tobacco Cessation to improve healing
    5. Complete appropriate cancer screening (for age, gender) before surgery
    6. Evaluation involves a team (primary provider, surgeon, nutritionist, behavioral health)
  2. Obstructive Sleep Apnea (not yet evaluated)
    1. Uncontrolled Sleep Apnea is a significant risk factor for anastomotic leak
    2. Obstructive Sleep ApneaPrevalence approaches 75% of patients pursuing Bariatric Surgery
    3. Delay procedure for Sleep Apnea evaluation with formal polysomonography
      1. If positive for Sleep Apnea, start CPAP and delay surgery for 4 weeks
  3. Venous Thromboembolism prophylaxis
    1. Common (1-3%) and a leading cause of mortality following Bariatric Surgery
    2. Risk Factors
      1. Body Mass Index >60 kg/m2
      2. Chronic Leg Edema
      3. Obstructive Sleep Apnea
      4. Prior Thromboembolism
      5. Estrogens
        1. Discontinue Estrogen containing Oral Contraceptives 1 month (1 cycle) before surgery
        2. Discontinue Estrogen containing Hormone Replacement Therapy 1 month before surgery
    3. Best prophylactic strategy is unclear
      1. Removable IVC Filters are commonly used in high risk patients (but inadequate evidence)
    4. Reasonable strategy
      1. Well-fitted Compression Stockings
      2. Early ambulation
      3. Enoxaparin 30 mg bid (40 mg bid if BMI>50)
      4. Consider removable IVC Filter for high risk patients

XVIII. Management: Post-Operative - General and Diet

  1. Monitoring of labs (see above)
  2. Continued education and reevaluation (quarterly in first year, annually thereafter)
    1. Includes dietician visits, nurse visits and surgical follow-up
    2. Assess weight, nutritional status, supplementation, symptoms and food intolerance at each visit
    3. Vitamin Supplementation, as well as nutritional and lab monitoring as above
  3. Imperative that patients continue life-long care
    1. Compliance with diet above
    2. Maintenance of regular physical Exercise program
    3. Continued behavioral methods to control food impulse
    4. Consider post-surgical support groups
  4. Dietary changes to avoid over-distention and Vomiting
    1. Immediately after Gastric Bypass
      1. Start with clear liquids and gradually progress to regular foods over first 3 months
    2. Longterm
      1. Start meal with Protein portion to ensure adequate Protein intake (80-90 g/day total)
      2. Cut food into small bite size amounts (as if using toddler utensils)
      3. Chew well (to applesauce consistency) before Swallowing
      4. Eat slowly and without distraction (finish a meal within 30 minutes)
      5. Avoid drinking fluids 30 minutes before and 30-60 minutes after each meal (reduces satiety)
      6. Avoid carbonated beverages (gas forming)
      7. Identify fullness Sensation and stop eating immediately when you feel this
      8. Anticipate and avoid foods likely to be difficult to swallow (dry foods, bread, fibrous vegetables)
    3. Consider Acute Thiamine Deficiency (Wernicke's Encephalopathy) in acute confusional state presentations
      1. Empirically dose with 100-500 mg Thiamine IV at presentation
  5. Other dietary changes
    1. Limits foods with substantial simple Carbohydrates, Sorbitol or high fats (avoids dumping)
    2. Stay hydrated by taking 64 ounces non-caffeinated fluid and avoiding Alcohol
    3. Avoid carbonated beverages
  6. Vitamin Supplementation
    1. Bariatric Multivitamin chewable once to twice daily (twice daily if status-post Roux-en-Y Bypass)
    2. Vitamin B12 Supplementation (1000 mcg IM monthly or 1000 mcg orally daily)
    3. Calcium Citrate 1200 to 1500 mg daily (do not take within 2 hours of iron)
    4. Vitamin D 3000 IU daily (titrate to 25-Hydroxyvitamin D >30 ng/ml)
    5. Iron Supplementation 45-60 mg/day (may be higher in menstruating women)
    6. Maintain adequate Dietary Protein intake (see above)
    7. Additional supplements if deficiency identified (recheck monthly until normal)
      1. Thiamine 50 mg orally daily for 6 months
      2. Vitamin B6 50 mg orally daily
      3. Folate 1 mg orally daily

XIX. Management: Post-Operative - Specific Conditions

  1. Type 2 Diabetes Mellitus
    1. Significant improvement expected after Bariatric Surgery
      1. Complete Diabetes Mellitus remission in up to 70% following surgery (sustained at 10 years in 38%)
      2. Insulin requirement eliminated in up to two thirds of patients at 1 year
      3. Microvascular complications are reduced for up to 20 years after Bariatric Surgery
    2. Medications
      1. Avoid agents associated with Hypoglycemia (e.g. Sulfonylureas)
      2. Decrease Mealtime Insulin (Bolus Insulin) by 50% or eliminate
      3. Consider decreasing Basal insulin (e.g. Insulin Glargine) by 50 to 75%
      4. Continue frequent home Blood Glucose Monitoring
      5. Consider GLP1 Agonist (e.g. Liraglutide) to augment weight loss in first post-operative year
        1. Miras (2019) Lancet Database Endocrinol 7(7): 549-59 [PubMed]
        2. Mok (2023) JAMA Surg 158(10): 1003-11 [PubMed]
    3. References
      1. Vahtera (2024) Br J Surg 111(4):znae105 +PMID: 38682425 [PubMed]
      2. Sjostrom (2014) JAMA 311(22): 2297-304 +PMID: 24915261 [PubMed]
  2. Cardiovascular Disease and Hypertension
    1. Significant improvement in Cardiovascular Risk Factors after Metabolic Surgery
      1. Significant reduction in CAD/MI, CHF and new onset Atrial Fibrillation
      2. Hypertension remission may occur in up to 40% of patients within 5 years of surgery
        1. However remission is not consistently sustained
    2. Antihypertensives
      1. Monitor Blood Pressure including home monitoring
      2. Blood Pressure decrease may start as early as 2 weeks after surgery
        1. However Blood Pressure often fluctuates following surgery
      3. Monitor Blood Pressure in pre and post-operative period
        1. Do not preemptively stop Antihypertensives (instead, adjust based on monitoring)
    3. AntiHyperlipidemics (e.g. Statins)
      1. Monitor and adjust as needed
    4. References
      1. Hawkins (2018) Obes Surg 28(7): 1845-51 [PubMed]
      2. Reynolds (2021) Hypertension 78(4): 1116-25 [PubMed]
      3. von Veldhuisen (2022) Eur Heart J 43(20): 1955-69 [PubMed]
  3. Obstructive Sleep Apnea (OSA)
    1. Nearly 74% of OSA patients were able to stop CPAP at 1 year post-Metabolic Surgery
      1. Stenberg (2024) J Am Coll Surg 239(2): 77-84 [PubMed]
    2. Continue CPAP postoperatively
      1. Obtain Sleep Study after 20% weight loss
  4. Osteoporosis (increased risk after Bariatric Surgery)
    1. Obtain DEXA Scan 2 years after surgery
    2. Avoid oral Bisphosphonates due to esophageal ulcer risk (at least in short term following Bariatric Surgery)
    3. Consider IV Reclast or Boniva instead if bisphosphonate needed
  5. Gallbladder
    1. In patients with an intact gallbladder, rapid weight loss may be associated with Gallstone development
    2. Consider Gallstone prophylaxis with ursodial for 6 months after surgery
  6. Major Depression and Suicidality
    1. Major Depression may transiently improve after Bariatric Surgery
    2. Major Depression has a higher risk of recurrence 12-24 months after Bariatric Surgery
      1. Inadequate weight loss (or unmet expectations)
      2. Persistent Obesity related complications
      3. Weight regain
      4. Excess, redundant skin after weight loss (e.g. panus)
      5. Lagerros (2017) Ann Surg 265(2): 235-43 [PubMed]
    3. Increased risk of Suicidality and self-harm after Bariatric Surgery
      1. Continue to screen for Major Depression and Suicidality at regular intervals after surgery
      2. Castaneda (2019) Obes Surg 29(1): 322-33 [PubMed]
  7. Alcohol Use Disorder
    1. Alcohol sensitivity increases significantly after surgery (esp. Roux-en-Y gastric bypass)
    2. Avoid replacing Overeating with Problem Drinking
  8. Miscellaneous
    1. Consider gout prophylaxis

XX. Management: Post-Operative - Women's Health

  1. Background
    1. Women represent nearly 80% of Bariatric Surgery patients (and most are of child-bearing age)
  2. Contraception
    1. Ensure reliable pregnancy prevention after Obesity Surgery
    2. Avoid conception for at least 12-24 months post-op (or stable, with<5% weight loss in last 3-6 months)
      1. Fetal development may be impaired by rapid maternal weight loss
      2. Fertility improves as women lose weight (e.g. PCOS improvement)
    3. Intrauterine Device (IUD) is a preferred effective option in all patients regardless of surgery type
    4. Roux-en-Y Bypass
      1. Use non-oral formulations (e.g. Mirena IUD)
      2. Avoid Oral Contraceptives (decreased efficacy)
    5. Restrictive procedures (Gastric banding)
      1. Oral Contraceptives are acceptable option (if not frequently Vomiting)
        1. However, risk of Venous Thromboembolism (Exercise caution)
      2. Avoid Ortho Evra patch or drospirenone OCPs due to increased VTE Risk
  3. Pregnancy
    1. Delay pregnancy for >18-24 months post-procedure (higher risk of adverse outcomes)
      1. Use reliable Contraception during this time
      2. Preconception correction of nutritional deficiencies
    2. Obesity Surgery decreases overall pregnancy-related complication risk
      1. Lower risk of Preeclampsia
      2. Lower risk of Gestational Diabetes
    3. Pregnancy after Bariatric Surgery has different complication risks
      1. Nutrient deficiency (e.g. Folate Deficiency, Thiamine Deficiency)
      2. Fetal Growth Restriction and Small for Gestational Age infant
    4. Supplement
      1. Protein: Additional extra 10 grams per day
      2. Vitamin B12: 1000 mcg sublingual weekly
      3. Folic Acid 800 mg orally daily
      4. Iron 325 mg orally daily
      5. Vitamin C 500 mg orally daily
      6. Calcium 1200 mg orally daily
      7. Prevent additional weight loss and expect weight gain during pregnancy
      8. Consider adjustment of Lap band pressure
    5. Gestational Diabetes screening (at 24-28 weeks)
      1. Background
        1. Glucose Challenge Test after Bariatric Surgery is less accurate due to dumping syndrome
      2. Adustable Gastric banding
        1. May undergo standard oral Glucose challange test
      3. Home oral Glucose challange test 1 week protocol
        1. Obtain 1 week of home Fasting and 2 hour post-prandial Glucose readings
  4. Postpartum
    1. Breastfeeding
      1. Ensure adequate continuation of Nutritional Supplements
    2. Postpartum Depression
      1. Postpartum Depression screening at intervals after delivery
  5. Gynecologic Cancer Prevention
    1. Obesity is a risk for Breast Cancer, Ovarian Cancer and Endometrial Cancer (and may be reduced with Obesity Surgery)
    2. Continue routine cancer screening after surgery
    3. Lim (2024) JAMA Surg 159(3): 331-8 [PubMed]

XXI. Management: Post-Operative - Medications

  1. General formulations and pill size
    1. Initial first 4 weeks after surgery
      1. Limit medication forms to liquids, crushable tablets or caplets that can be opened
    2. Longterm
      1. Limit medications to plain M&M size or smaller
      2. Avoid enteric coated or extended release formulation medications (erratic absorption)
        1. Depending on the surgery, some formulations may be allowed after the first 4 weeks
  2. Analgesics
    1. Acetaminophen is preferred
    2. Avoid NSAIDs due to Peptic Ulcer risk and anastomotic ulcers
      1. Surgeon may approve if absolutely unavoidable, combined with Proton Pump Inhibitor
    3. Caution with Systemic Corticosteroids
  3. Medications requiring dose modification (or elimination) as weight loss occurs
    1. Antihypertensives (see above)
    2. AntiHyperlipidemics (see above)
    3. Thyroid medications (e.g. Levothyroxine)
    4. Diabetes Medications (see above)
  4. Anticoagulation and antiplatelet agents
    1. Avoid DOACs (e.g. Eloquis, Xarelto)
    2. Aspirin 81 mg for cardiovascular indications is safe
    3. Warfarin levels are unstable in first 3-6 months (less Vitamin K, weight loss)
      1. Initial post-operative doses decrease, then increase to prior requirements
      2. Monitor INR closely during this time
  5. Venous Thromboembolism prophylaxis
    1. See Pre-op evaluation above
    2. May require DVT Prophylaxis for up to 4 months post-op depending on post-op mobility and prior VTE history
  6. References
    1. (2013) Presc Lett 20(12): 67-8
    2. Mechanick (2019) Endocr Pract 25(12): 1346-59 [PubMed]

XXII. References

  1. (2024) Presc Lett 31(8): 45
  2. Balsiger (2000) Mayo Clin Proc 75:673-80 [PubMed]
  3. Banerjee (2022) Am Fam Physician 105(6): 593-601 [PubMed]
  4. Buchwald (2004) JAMA 292:1724-37 [PubMed]
  5. Chang (2014) JAMA Surg 149(3): 275-87 [PubMed]
  6. Choban (1997) J Am Coll Surg 185:593-603 [PubMed]
  7. Green (2026) Am Fam Physician 113(5): 469-78 [PubMed]
  8. Virji (2006) Am Fam Physician 73:1403-8 [PubMed]
  9. Schroeder (2011) Am Fam Physician 84(7): 805-14 [PubMed]
  10. Schroeder (2016) Am Fam Physician 93(1):31-7 [PubMed]

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