A peer-reviewed, evidence-based journal that promotes clinical development and metabolic insights in total bariatric patient care for the healthcare professional
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November 2016 • Supplement B • Bariatric Times B21 FIRST INTERNATIONAL CONSENSUS CONFERENCE ON DUODENAL SWITCH at one and three years there is little difference between VSG and RYGB. 7 R ather than a single procedure for all, it is important to stratify. For those on oral medicine with a hemoglobin A1c (HbA1c) less than eight, any weight loss procedure, i ncluding VSG, will likely be effective. For those on insulin, especially for a lengthy period, and an elevated HbA1C, the BPD or similar procedures will be best. At least, VSG is relatively easy to convert to a BPD-DS, SIPS, or SADI (Single-anastomosis Duodeno-ileal Bypass with Sleeve Gastrectomy). For those with long standing diabetes, on insulin and with poor control, a RYGB may not be adequate and further revision difficult. RYGB does many things that improve diabetes. Early, a change in caloric consumption causes lipolysis. There is a change in hepatic endogenous glucose production and improved hepatic insulin sensitivity. But the major factor is increased insulin production secondary to improved beta cell sensitivity and an integrin response. This means that if B cell function is damaged beyond a certain point, or gets worse, RYGB will not work. 12 In comparison, there have been several studies that examine DS or BPD in patients with long standing diabetes that have required insulin for numerous years. 13 In patients on insulin for 5 to 10 years, BPD-DS resulted in a resolution rate of 88 percent. 13 The exact mechanisms are still being studied, but it appears that BPD-DS has a much more dramatic effect on peripheral insulin resistance especially in muscle tissues. 13 Therefore, less insulin is required to maintain euglycemia. Procedures that increase bile salt diversion seem to have the same efficacy. SIPS, SADI, BPD, and BPD-DS all feature a lengthy BP limb. It remains unknown why diversion of bile salts improves diabetes remission. Potential explanations include alteration of the microbiome, reduction of inflammation, or changes in fibroblast growth factors. Whereas the contribution to weight loss of the intestine is not well understood in RYGB, we have a reasonable understanding in SIPS. Cottam et al 14 performed a matched cohort analysis that compared VSG to SIPS at 18 months. At six months post operatively, there was 10- percent difference in weight loss. By 18 months, the difference was up to 30 percent, with SIPS patients losing significantly more weight. Additionally, of interest, the VSG patients reached maximum weight loss at 8 to 9 months. SIPS patients continued to lose weight until 14 to 16 months. 14 Mitzman et al 3 published the early results of Drs. Cottam and Roslin in 2016. 3 These results showed that at one year, patients lost more than 21 BMI units. Of interest, there was little variation in weight loss between the two sites. 3 The consistency of these results demonstrates the strength of the procedure as there was little variability. The greater the variance, the more the results are due to patient characteristics than the procedure itself. Based on these results, a five center case series was designed that completed enrollment in Fall of 2015. Early data is very similar to the results above. The one year follow up on all patients are expected be completed in the Fall of 2016. Additionally, Roslin et al presented a series of 168 cases at the 21st World Congress of the International Federation for the Surgery of Obesity & Metabolic Disorders (IFSO 2016), September 28 to October 1, 2016, in Rio de Janerio, Brazil (Table 1). More than 20 patietns have three-year follow up and weight loss remains robust. There was one death from a cardiac cause several weeks post surgery, two mesenteric venous thrombosis cases, and one chylous fistula. There was a single anastomotic leak treated with percutaneous drainage. There was not a single case of small bowel obstruction, marginal ulcer, anastomotic stricture or complication from the loop configuration (Table 2). Additionally, at one year with blood work on 80 patients, mean vitamin D level was 29. No patient had an albumin level less than 3.0 mg/dl. Although, 79 patients in this series were diabetic, to date a separate analysis has not been done (Table 3). Table 3. Results from Roslin et al series of 168 cases of SIPS (Stomach, Intestine and Pyloric Sparing Surgery: A Modified Duodenal Switch): Nutritional Data VARIABLE PRE- OPERATION POST OPERATION 1–180 DAYS POST-OPERATION >180 DAYS Vitamin D 24 26 29 Vitamin B1 117 101 121 Vitamin B12 597 1055 1105 Vitamin A 58 37 38 Albumin 4.1 4 4