Gastric Bypass After Previous Anti-reflux Surgery
Condition: Clinically Severe Obesity; Gastroesophageal Reflux Disease
MeSH terms: Gastroesophageal Reflux; Obesity, Morbid
Study type: Observational

Summary: 
      The goal of this study is to describe the clinical presentation, indications, and operative
      treatment as well as assess the morbidity, mortality, and overall performance of revisional
      Roux-en-Y gastric bypass (RYGB) after either failed or functional antireflux surgery "ARS" in
      obese patients. With such information, we hope to determine which features might assist us in
      advancing our knowledge about Gastro-Esophageal Reflux Disease "GERD", the best option for
      primary ARS, and mechanisms of failure in the obese population as well as in identifying
      predictors of outcome after revisional surgery in this population.
    

Detailed description: 
      The epidemic of overweight and obesity in the United States of America along with its
      comorbidities continues to expand. Bariatric surgery has demonstrated to be the most
      effective and sustained method to control severe obesity and its comorbidities. For instance,
      type 2 diabetes mellitus was completely resolved in 76.8 percent, systemic arterial
      hypertension was resolved in 61.7 percent, dyslipidemia improved in 70 percent, and
      obstructive sleep apnea-hypopnea syndrome was resolved in 85.7 percent. Furthermore,
      bariatric surgery significantly increases life expectancy (89 percent) and decreases overall
      mortality (30-40 percent), particularly deaths from diabetes, heart disease, and cancer.
      Lastly, preliminary evidence about downstream savings associated with bariatric surgery
      offset the initial costs in 2 to 4 years.

      Since 1998, there has been a substantially progressive increase in bariatric surgery. In
      2005, the American Society of Metabolic and Bariatric Surgery "ASMBS" reported that 81
      percent of bariatric procedures were approached laparoscopically. 205,000 people, in 2007,
      had bariatric surgery in the United States from which approximately 80 percent of these were
      Gastric Bypass. Moreover, there is a mismatch between eligibility and receipt of bariatric
      surgery with just less than 1 percent of the eligible population being treated for morbid
      obesity through bariatric surgery. Along with the increasing number of elective primary
      weight loss procedures, up to 20 percent of post RYGB patients cannot sustain their weight
      loss beyond 2 to 3 years after the primary bariatric procedure. Thus, revisional surgery for
      poor weight loss and re-operations for technical or mechanical complications will rise in a
      parallel manner.

      Three systematic reviews and meta-analysis have examined the association between obesity (BMI
      >30kg/m2) and several GERD-related disorders, including 1) GERD symptoms, 2) erosive
      esophagitis "EE", and 3) esophageal adenocarcinoma "EA". Obesity is associated with a
      1.5-to-2-fold increased risk of GERD symptoms and EE and a 2- to 2.5-fold increased risk of
      EA. In two large case-control studies, abdominal diameter (waist-hip ratio), but not BMI, is
      an independent risk factor for another GERD-related disorder, Barrett´s esophagus "BE".

      Current pathophysiological mechanisms of GERD in the obese encompass the following. 1)
      Mechanical: I) increased intra-gastric pressure: increased intra-peritoneal and abdominal
      wall fat mass increases the intra-abdominal and peri-gastric pressures with subsequent
      increased gastroesophageal pressure gradient "GEPE" with augmented esophageal acid exposure.
      Each BMI unit increase corresponds to a 10 percent increase in intra-gastric pressure. II)
      Hiatal Hernia: "HH" disrupts the integrity of the sphincter mechanisms and prolongs
      esophageal acid clearance. Thin, normal, overweight, and obese subjects have a 1.0, 1.9, 2.5,
      and 4.2 risk of having HH compared to thin subjects, respectively. 2) Motility: I) Increased
      Transient LES Relaxation "TLESR" are associated with acid reflux during the postprandial
      period, especially during inspiration. II) Low LES basal pressure: Increased prevalence of
      abnormally low LES basal pressure in the overweight and obese in comparison to the
      normoweight subject. III) Esophageal motility abnormality: Jaffin et al, with esophageal
      manometry, reported 61 percent of patients with altered esophageal motility from which 59
      percent had altered visceral pain perception (asymptomatic). IV) Delayed gastric emptying:
      mostly associated with one of its major comorbidities, diabetes mellitus. 3) Esophageal
      sensitivity: Mercer et al., with a Bernstein test, found a significant difference between
      normoweight and obese subjects without clinical evidence of GERD (0 percent vs. 86 percent,
      respectively) for esophageal hypersensitivity. 4) Hormonal: mostly mediated by estrogen and
      adiponectin. 5) Environmental (Diet): high-fat, saturated fatty acids, high-cholesterol, and
      high caloric density diets have been associated with the highest likelihood of perceiving an
      acid reflux event; fat may confer its sensory effect by activating pain facilitatory pathways
      or by deactivating pain inhibitory pathways.

      The most recent data is not conclusive on whether increased BMI affects acid-suppressive
      therapy for GERD. However, MacDougall et al. found that increased BMI was significantly
      associated with long-term acid suppression therapy. This can be explained based on either a
      higher prevalence of factors that predispose overweight and obese subjects to severe GERD,
      such as HH, greater GEPG, increased number of TLESR, or standard doses of PPI´s are
      suboptimal for patients with increased BMI and GERD.

      Broad indications for antireflux surgery include: 1) Reflux of food associated with HH, 2)
      despite successful medical treatment or after poor or moderate symptom control on optimized
      PPI therapy, patient opts for surgery, and 3) Complicated GERD without including severe
      dysplasia.

      Available traditional ARS are either 1) fundoplication, which is the most commonly performed
      procedure and can be partial -Toupet, Dor- or complete -Nissen-, or other procedures with
      limited use such as 2) Hill operation, 3) pyloroplasty, 4) vagotomy with antrectomy, and 5)
      duodenal switch.

      Long-term control of typical symptoms after primary laparoscopic Nissen fundoplication "LNF",
      in properly selected patients and with an experienced surgical team, is attained in more than
      90 percent of patients confirming that LNF is the gold standard for the treatment of severe
      GERD.

      In a cohort study of 166 patients followed for 11 years, Smith et al found preoperative
      response to acid-reducing medication, typical symptoms, and BMI < 35 Kg/m2 to predict
      successful outcome. However, HH size, normal 24-hour pH score, age > 50 years, female gender,
      and prior abdominal surgery that previous studies found to be associated with poor outcomes
      were not corroborated by this study. Other risk factors for failure are short esophagus, HH
      greater than 3 cm, and diaphragmatic stressors such as retching, sports of weight lifting,
      and high-speed motor vehicle accident among others.

      Another study found increased BMI to be a predictor of poor outcome. Perez et al, in a
      retrospective cohort analysis of 224 patients undergoing LNF and transthoracic ARS, found a
      significantly increased recurrence rate of GERD in obese and overweight compared to
      normoweight patients, regardless of procedure type.

      In contrast, a cohort study of 257 consecutive patients undergoing LNF, D´Alessio et al
      analyzed outcomes based on BMI (< 25, 25-30, and >30 kg/m2); No significant differences in
      symptom scores and clinical success rates were found among the different subsets. However,
      mean BMI for obese patients was 33 kg/m2 (obesity class I) and only three patients were >35
      kg/m2.

      Regardless of contradictory data about LNF efficacy in obesity, several studies have shown
      the effectiveness of RYGB for GERD in morbidly obese patients by symptoms, endoscopic
      findings, manometry and pH-metry results, and endoscopic biopsy-histopathology.

      There are four retrospective cohort studies assessing mostly early outcomes after converting
      ARS to RYGB. First, Sarr et al analyzed 19 patients that underwent open conversion to RYGB.
      Next, Ikramuddin et al described the anatomic findings for fundoplication failure after the
      laparoscopic conversion to RYGB of 11 patients. Lastly, with seven patients each, Raftopoulos
      et al and Donnelly et al reported feasibility with a high morbidity rate as well.

      In summary, there is little information about what is the best primary ARS and the best
      revisional strategy to address intractable or severe reflux after failed fundoplication in
      the obese population. Also, there is lack of data about the best revisional procedure to
      address obesity in the patient status post functional or competent ARS. With this pilot
      retrospective study, we will advance our knowledge and along with the existing literature, we
      will draw preliminary clinical recommendations.
    

Observational model: Cohort
Time perspective: Retrospective
Sampling method: Non-Probability Sample
Study population: 
        Patients who underwent laparoscopic Roux-en-Y gastric bypass (RYGB) after a previous
        functional or failed anti-reflux procedure and met National Institutes of Health criteria
        for bariatric surgery.
      
Keywords: Obesity; Gastroesophageal Reflux Disease; Nissen funduplication; Antireflux surgery; Revisional Gastric Bypass; Re-operative bariatric surgery; Bariatric surgery; Nissen; Conversion of Nissen to Gastric Bypass