Surgical Innovation for Diabetes Treatment 2

This study aims to understand the enteroendocrine physiological changes in superobese patients submitted to two different bariatric procedures (biliopancreatic diversion with duodenal switch versus single anastomosis duodeno-ileal bypass), when perfomed as primary or revisional surgeries (after a sleeve gastrectomy). The main purpose is to establish the metabolic changes obtained with the sleeve gastrectomy and how the revisional procedure maximizes those changes. Additionally, the study will determine whether BPD with DS or SADI-S is superior than the other as first choice for the superobese.

The study will monitor the enteroendocrine function before and after the ingestion of a mixed meal, in pre-operatory and post-surgery timepoints, comparing both primary and revisional surgeries.

Abstract Obesity is a chronic disease whose global incidence keeps rising as the twenty first century goes on. Nowadays, the surgical approach constitutes the best treatment option for these patients, making the sleeve gastrectomy and the gastric bypass the more frequently performed bariatric surgeries.

However, the superobese patients (IMC≥ 50kg/m2) present variable weight loss resistance to the previous techniques, showing better results when submitted to disabsorptive procedures, namely the biliopancreatic diversion with duodenal switch, and the more recently created single anastomosis duodeno-ileal bypass. Each constitutes a revisional surgery option after a primary sleeve gastrectomy, reducing surgical and anesthesia risks. This has brought to light that some superobese patients do not need the revisional procedure as they achieve the weight loss target solely by the vertical gastrectomy.

Supported on the investigators' previous work and extensive experience performing both techniques, they now aim to understand the enteroendocrine physiological changes which each procedure accomplishes and compare them in terms of therapeutic efficacy among the superobese. The utmost goals will be to unravel the advantages of BPD-DS and SADI-S as primary or revisional surgeries, the differences between patients that respond well to sleeve gastrectomy alone and those who do not, and, finally, providing further insights on which procedure should be favoured over the other based on the patient characteristics.

Study Overview:

Participants in this study will have been submitted to either BPD-DS or SADI-S, as a primary or as a revisional surgery.

* Participants visits will be scheduled before surgery and after surgery at 3, 6 , 12 and 24 months for those who receive BPD-DS or SADI-S as a primary procedure.
* Those who are firstly submitted to the sleeve gastrectomy, visits will be scheduled before surgery and after surgery at 3 , 6 and 12 months. The revisional surgery will take place 1 year after the sleeve, with visits scheduled before surgery and after surgery at 3, 6 and 12 months.

In all these visits, detailed participants assessment will include vitals, anthropometric and biochemical evaluation, and the performance of a MMTT with plasma sampling for hormonal profiles. Intraoperative sampling of visceral and subcutaneous adipose tissue will take place during BPD-DS or SADI-S as a primary procedure and during the sleeve gastrectomy and repeated 1 year after the revisional surgery, either BPD-DS or SADI-S, is performed.

Participant Enrolment:

Participants will be selected from the cohort of patients referred for multidisciplinary evaluation by the clinical team for surgical treatment of obesity of the Centro Hospitalar Entre Douro e Vouga (CHEDV). Participants found to be suitable according to the entry criteria and who have accepted to participate will be enrolled in the study and assigned to one of the four study groups according to participants clinical features.

Eligibility Criteria:
Inclusion Criteria:

Bariatric surgery candidates

* BMI between 45 and 55 kg/m2
* Aged between 18 and 65 years at surgery

Exclusion Criteria:

* Previous abdominal surgery
* Diabetic patients (Hb A1c \> 5,7%) prior to the bariatric procedure
* Treatment with antidiabetic drugs, except for purposes other than diabetes treatment, prior to the bariatric procedure