The primary objective of this open-label pilot study is to investigate whether an endoscopically placed lumen apposing metal stent is an effective alternative to surgery in patients that have a clear indication for reversal of their gastric bypass.

Inclusion Criteria:

• Group 1) patients needing any kind of parenteral nutritional support (eg. hypo- albuminemia, hypovitaminoses, mineral deficiencies,...) that can not be corrected by dietary intervention/oral supplementation
• Group 2) patients with persistent invalidating symptomatic dumping syndrome despite optimal dietary intervention (typical complaints are headache, sweating, trembling, weakness and feeling hungry).
• Group 3) patients with a refractory marginal ulcers with stenosis of the gastrojejunostomy leading to feading difficulties.
• Group 4) patients with F3 or F4 liver fibrosis and a tendency to decompensation after bypass surgery, as demonstrated by an increase in serum bilirubin/INR and/or lowering of serum albumin.

Exclusion Criteria:

1. Uncorrectable coagulopathy

2. Presence of significant portal hypertension as demonstrated by 2.1) the presence of esophageal and/or gastric varices AND/OR 2.2) a hepatic venous pressure gradient (if measured) equal to or more than 10mm Hg AND/OR 2.3) the combination of

   1. a platelet count <150000/µl AND
   2. liver stiffness measured by elastometry equal to or more than 20 kPa (Baveno guidelines).

3. Pregnant women, breastfeeding women or women that can not assure adequate anticonception for the duration of the study (based on anamnesis).

4. Karnofsky index less than 60

5. Vulnerable patients