Laparoscopic Revision From Biliopancreatic Diversion to Gastric Bypass
Condition: Metabolic and Nutritional Complications; Protein Malnutrition; Intestinal Malabsorptive Syndrome; Metabolic Bone Disease
MeSH terms: Bone Diseases; Bone Diseases, Metabolic; Malnutrition; Kwashiorkor
Study type: Observational

Summary: 
      The aim 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
      GBP after either failed and/or complicated Biliopancreatic Diversion "BPD" for weight loss.
      With such information, we hope to determine what features might assist us in advancing our
      knowledge about mechanisms of failure after primary bariatric surgery, mechanism of action of
      revisional GBP, and performance of revisional GBP through traditional outcome measurements as
      well as identifying predictors of good or poor outcome after revisional GBP in this specific
      subpopulation.
    

Detailed description: 
      In Italy, Professor Nicola Scopinaro, after studies in dogs, performed the first BPD in
      humans in 1976. Because of the lack of blind-loop syndrome and selective malabsorption for
      starch and fat, the BPD has an accepted risk-benefit ratio compared to the long ago abandoned
      Jejunoileal Bypass (a purely malabsorptive procedure). BPD side effects after resumption of
      full food intake include 2 to 4 bowel movements "BM" per day of foul-smelling, soft stools
      with flatulence. Modification of food habits and/or administration of neomycin or
      metronidazole for bacterial overgrowth syndrome tend to decrease BPD side effects after the
      disappearance of the postcibal syndrome somewhere around the fourth postoperative month.

      To optimize its performance but mainly to decrease the protein malnutrition incidence, the
      BPD has undergone several modifications until 1992 when the ad hoc stomach-ad hoc alimentary
      limb BPD configuration was implemented. Consequently, the early sporadic and late recurrent
      forms of protein malnutrition have decreased from as high as 30% and 10% to as low as 2.0%
      and 1.0%, respectively.

      PROTEIN-CALORIE MALNUTRITION

      I) After BPD Protein-calorie malnutrition "PCM" is multifactorial and depends on
      patient-related factors (such as eating habits, capacity to adapt these to requirements set
      by the surgery, and socio-economic status) and technical factors (including gastric volume,
      bowel limb lengths, intestinal absorption and adaptation, and amount of endogenous nitrogen
      loss). Most cases are limited to a single or sporadic episode. In the early postoperative
      period secondary to the forced reduced food intake, the marasmic form of PCM incidence is
      higher, which is the aim of the operation. However, when carbohydrate intake is preferred
      (poor compliance with adequate protein intake), the hypoalbuminemic form will develop. The
      absorptive capacity of the alimentary limb "AL" and common limb or channel "CC" depends on 1)
      number of villi per square centimeter, 2) transit time, and 3) total intestinal length of the
      AL + CC. Thus, any condition that interferes with postoperative intestinal adaptation, mainly
      villous hypertrophy; increased transit time; and/or decreases the length of the functional AL
      + CC will lead to late onset of severe PCM. Increased number of bowel movements "BM" or
      severe diarrhea generally precedes to PCM.

      After adequate counseling with life-style changes (mainly consumption of more than 90 g/day
      of high biological value protein), supplementation with pancreatic enzymes, and management of
      contributing medical conditions (such as gastroenteritis, lactose intolerance, intestinal
      bacterial overgrowth syndrome, celiac sprue, and inflammatory bowel disease), recurrent or
      severe PCM is frequently caused by excessive malabsorption. When mild or moderate protein
      malnutrition is instated, two to three weeks of parenteral nutrition are generally required
      to revert it. In contrast, severe PCM refers to the need for prolonged total parenteral
      nutrition "TPN", recurrent need for TPN, or malnutrition recalcitrant to TPN. Eventually,
      revisional surgery is required. The recurrent or severe form of PM is rarely secondary to
      excessive persistence of the food limitation mechanism with or without poor protein intake,
      requiring restitution of the intestinal continuity or complete reconstruction of the
      gastrointestinal tract (partial vs. full restoration). The partial restoration of the
      gastrointestinal tract allows normal protein-energy absorption, still partially preserving
      the specific effects of BPD on glucose and cholesterol metabolism.

      II) After RYGB

        1. Over a seven-year period, Avinoah et al. reported the nutritional status of 200 RYGB
           patients. Meat intolerance was observed in 51%, 60.3%, 59.5% and 55.1% of the patients
           during the 1st year, 2nd year, 3rd to 6th years, and 7th year after RYGB, respectively.
           No protein-calorie malnutrition was identified.

        2. Moize et al. evaluated food consumption after 93 RYGB patients finding that inadequate
           protein intake is related to protein intolerance up to one year. Protein intake
           increased significantly over the first postoperative year from 45 g at 3 months, 46 g at
           6 months, and to 58 g at 12 months. Low protein intake along the first year after RYGB
           is mainly related to intolerance to rich-protein food such as animal protein, mainly red
           meat.

        3. There are no studies that quantify protein malabsorption after short-limb RYGB or any
           kind of RYGB variant. However, the less acidic environment of the gastric pouch after
           RYGB delays protein digestion by affecting the release of a cascade of peptides and
           enzymes, including pepsinogen, gastrin, and cholecystokinin which are involved in the
           initial breakdown of proteins.

        4. In 236 consecutive short-limb, (6.3cm) banded RYGB patients, Faintuch et al. identified
           4.7% patients with severe hypoalbuminemic malnutrition from which 63.6% had defined
           events, such as stenosis at the gastrojejunostomy (36.4%) or associated diseases, and
           36.4% had severe emesis without any endoscopic abnormality.

        5. In a series of 342 consecutive ringed RYGB, White et al. reported a 2% ring removal rate
           after placing a 6.5cm ring in 92 patients because of major restriction to solid foods.

        6. In 65 patients converted to distal RYGB, Fobi et al. reported a mean BMI decrease of 7
           kg/m2; however, 23% of patients developed protein malnutrition requiring revision
           surgery almost 50% of them.

        7. In 27 distal RYGB at the 3rd postoperative year, Sugerman et al. reported a 25%
           incidence of protein malnutrition for the 150-cm common channel RYGB (n=22). In
           contrast, all five patients with a 50-cm common channel needed elongation of the common
           channel and two died of hepatic failure.

      After extensive review of the literature, Kushner listed principal variables that contributed
      to nutritional deterioration after bariatric surgery: 1) sever malabsorption after
      malabsorptive procedures such as BPD or BPD-DS and distal or very, very long-limb RYGB; 2)
      surgical mechanical complications, such as stenosis at the gastrojejunostomy, intractable
      marginal ulcer, and gastro-gastric fistula; and 3) Non-compliance

      Same analysis and review of the literature is available but less extensive for Metabolic bone
      disease, Anemia (Iron, folate, and vitamin B12), liposoluble vitamins and essential fatty
      acids.

      Revisional strategies:

      Revisional strategies that have been described for long-term complications after BPD are 1)
      elongation of common limb or channel, 2) restoration of intestinal continuity (partial
      restoration), and 3) restoration of gastrointestinal continuity (full restoration).

      RYGB vs. BPD: Roux-en-Y configuration

        1. Weight maintenance after BPD or BPD-DS appears to be superior to that after restrictive
           procedures and RYGB. However, this has never been subjected to a randomized controlled
           trial.

        2. Intuitively, one would expect macro and micronutrient deficiency after bariatric surgery
           to be more frequent and severe when primarily malabsorptive with some restriction or
           pure malabsorptive procedures have been carried out, and this has been shown to be
           correct (level of evidence 3 or C).

        3. Comparing the incidence rate of the largest series performed by experts, the incidence
           rate of late metabolic/nutritional complications after standard BPD/BPD-DS is higher
           than after standard RYGB.

        4. There are trials with a level of evidence 3 & 4 (C & D) that favor the overall
           superiority of RYGB over BPD for clinically severe obesity including among others the
           following:

             -  RYGB has been around longer than BPD

             -  Widespread use of RYGB compared to BPD

             -  Comparable weight loss however BPD has better weight maintenance than RYGB

             -  RYGB has lower morbidity and mortality than BPD including metabolic/nutritional
                problems, which are more prevalent in BPD than in RYGB.

             -  RYGB, in general, is accepted as the best revisional strategy for failed/
                complicated restrictive procedures and even malabsortive surgeries such as the
                jejunoileal bypass

      Summarizing, there is no evidence level A or 1 about what is the best overall primary
      bariatric procedure to address obesity at the long-term. In the USA, most investigators
      prefer RYGB for primary bariatric procedure, leaving BPD or BPD-DS for select cases including
      revisionary surgery for poor weight loss. After RYGB and BPD/BPD-DS, patients require to give
      priority for protein intake over other macronutrients as well as vitamin and mineral
      supplementation lifelong; there is no objective and standardized recommendation for
      supplementation. However, when metabolic/nutritional complications after BPD or BPD-DS
      develops regardless of optimized multispecialty medical management, lengthening of the common
      channel and partial or full reversals have been described. On the other hand, one-stage
      revision, either open or laparoscopic, from BPD to standard RYGB has never been reported.
      With this study, we will advance our knowledge about revisional RYGB, metabolic complications
      after hybrid bariatric procedures, 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 referred with severe, persistent and/or recurrent metabolic/nutritional
        complications after open biliopancreatic diversion for clinically severe obesity underwent
        either laparoscopic or open conversion to Roux-en-Y gastric bypass. Intractability after
        interdisciplinary optimized medical therapy for metabolic and/or nutritional complications
        warranted surgical management.
      
Keywords: complicated biliopancreatic diversion; failed biliopancreatic diversion; revision gastric bypass; conversion bariatric surgery; revision bariatric surgery; re-operative bariatric surgery; malabsorptive syndrome; protein malnutrition; metabolic bone disease