Jorge Arroyo Vázquez1, Maria Bergström1, Steven Bligh2, Barry McMahon2, Per-Ola Park1. 1Dept. of Surgery, South Älvsborg Hospital, Borås, Sweden, 2Trinity Academic Gastroenterology Group, Trinity College & Tallaght Hospital, Dublin, Irland
Introduction: Stent treatment in the gastrointestinal tract is emerging as a standard therapy for overcoming strictures and sealing perforations. We have started to treat patients with perforated duodenal ulcers using a partially covered stent and external drainage achieving good clinical results. Stent migration is a serious complication that may require surgery. Pyloric physiology during stent-treatment has not been studied and mechanisms for migration are unknown. The aims of this study were to investigate the pyloric response to distention mimicking stent-treatment, using the EndoFLIP, investigating changes in motility patterns due to distention at baseline, after a pro-kinetic drug and after food ingestion.
Methods: A non-survival study in five pigs was carried out, followed by a pilot study in one human volunteer. A gastroscopy was performed in anaesthetized pigs and the EndoFLIP was placed through the scope straddling the pylorus. Baseline distensibility readings were performed at stepwise balloon distention to 20ml, 30ml, 40ml and 50ml, measuring pyloric cross sectional area and pyloric pressure. Measurements were repeated after administration of a pro-kinetic drug (Neostigmin) and after instillation of a liquid meal. In the human study readings were performed in conscious sedation at baseline and after stimulation with metoclopramide.
Results: During baseline readings the pylorus was shown to open more with increasing distention, together with higher amplitude motility waves. Reaching maximum distention-volume (50 ml), pyloric pressure increased significantly (p=0.016) and motility waves disappeared. After pro-kinetic stimulation pyloric pressure decreased and motility waves increased in frequency and amplitude at 20, 30 and 40 ml distentions. After food stimulation pyloric pressure stayed low and motility waves showed increase in amplitude at distentions of 20, 30 and 40 ml. During both tests the pylorus showed higher pressure and lack of motility waves at maximum probe distention of 50 ml. Similar results were found in the human study.
Conclusions: The pylorus seems to acts as a sphincter at low distention but when further dilated starts acting as a peristaltic pump. When fully distended, pyloric motility waves almost disappeared and the pressure remained high, leaving the pylorus open and inactive.
Stent placement in the pylorus results in pyloric distention, possibly changing motility. This study indicates that a duodenal stent placed over the pylorus should have a high radial force in the pyloric part in order to dilate the pylorus and diminish the contraction waves, this might reduce stent migration.
Presented at the SAGES 2017 Annual Meeting in Houston, TX.
Abstract ID: 87392
Program Number: P447
Presentation Session: iPoster Session (Non CME)
Presentation Type: Poster