Pyloric Endoscopic Myotomy as treatment for patients with symptom of gastric outlet obstruction after oesophagectomy with gastric conduit.

The aim of this study is to evaluate the efficacy of endoscopic pyloromyotomy and the value of diagnostic measurements for identifying delayed gastric empyting and as predictive factors for outcome of treatment. We will observe the efficacy of the endoscopic pyloromyotomy. Patients will undergo an EndoFlip measurement which is not part of routine clinical practice and they will be subject to questionaires.

1. We hypothesise that the G-POEM (endoscopic pyloromyotomy) will be an effective and feasible technique as treatment of delayed gastric empyting.

1. Main study parameters/endpoints:
- Efficacy of G-POEM defined as success rate at 3 months, reported as patient reported outcome measurements (PROMS) using a 6 point Likert scale, answering the question: “How do you rate your symptoms after the G-POEM procedure as compared to the situa-tion before the procedure?” 1. symptoms fully disappeared, 2. significant improvement, 3. mild improvement, 4. no change, 5. bit worse, 6. significantly worse. A Likert score of 1 or 2 is considered clinical success.
- Feasibility of G-POEM defined as technical success of G-POEM procedure (i.e. the ability to perform a complete pyloromyotomy).
- Safety of G-POEM based on:
o Peri-operative G-POEM complications: perforation, bleeding, cardiopulmonary events.
o All severe adverse events (SAEs) defined as any unwanted events occurring within 5 days after G-POEM resulting in >72 hours prolonged admission, admission to a medi-um or intensive care unit, additional unplanned endoscopic procedures, unplanned ra-diological (e.g. coiling) or surgical interventions, or blood transfusion or death.
2. Secondary study parameters/endpoints:
- Durability of G-POEM, defined as the clinical success rate at 12 months reported as PROMs (see main study parameter 1).
- Success rate at 3 and 12 months based on:
o Objective parameters: post-G-POEM gastric emptying time on nuclear scintigraphy, post-G-POEM gastric emptying time on barium swallow, post-G-POEM EndoFlip® measurement, post-G-POEM gastroduodenoscopy findings.
o Subjective parameters: Gastric Cardinal Symptom Index (GCSI), dumping symptom score, regurgitation symptom score.
- Possible predictors for success or failure of G-POEM, based on:
o Objective parameters: pre-G-POEM gastric emptying times on nuclear scintigraphy, pre-G-POEM gastric emptying on barium swallow, pre-G-POEM EndoFlip®, pre-G-POEM gastroduodenoscopy (e.g. retention and/or dilation of gastric tube), previous success on BOTOX injection.
o Subjective parameters (patient reported outcomes): Gastric Cardinal Symptom Index (GCSI), dumping symptom score, regurgitation symptom score.
- Adverse events (AEs) defined as any unwanted events that arise following treatment and/or that are secondary to the treatment; events classified as severe adverse events (SAEs) are mentioned as primary endpoint.
- (changes in) Quality of life, based on SF-36 questionnaire.