Exploring pyloric dynamics in stenting using a distensibility technique

• Published in: Neurogastroenterology and motility 2018-12, Vol.30 (12), p.e13445-n/a
• Main Authors: Arroyo Vázquez, Jorge Alberto, Bergström, Maria, Bligh, Stephen, McMahon, Barry P., Park, Per‐Ola
• Format: Article
• Language: English
• Subjects: Anesthesia; EndoFLIP; endoscopy; Implants; Kirurgi; Metoclopramide; Mimicry; Motility; Pressure; pyloric motility; pylorus; Sphincter; stent treatment; Surgery; Ulcers
• ISSN: 1350-1925; 1365-2982; 1365-2982
• DOI: 10.1111/nmo.13445

Background Perforated duodenal ulcers can be treated with a covered stent. Stent migration is a severe complication, sometimes requiring surgery. Pyloric physiology during stent treatment has not been studied and mechanisms for migration are unknown. The aim of this study was to investigate the pyloric response to distention, mimicking stent treatment, using the EndoFLIP. Methods A nonsurvival study in five pigs was carried out, followed by a pilot study in one volunteer. Animals were gastroscoped during anaesthesia and the EndoFLIP was placed straddling the pylorus. Baseline distensibility readings were performed at stepwise balloon distentions to 20, 30, 40, and 50 mL, measuring pyloric cross‐sectional area and pressure. Measurements were repeated after administration of a prokinetic drug and after a liquid meal. In the human study, readings were performed in conscious sedation at baseline and after stimulation with metoclopramide. Key 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 prokinetic stimulation, the pressure decreased and the motility waves increased in frequency and amplitude. After food stimulation, the pressure stayed low and the motility showed increase in amplitude. During both tests, the pylorus showed higher pressure and lack of motility waves at maximum probe distention. Conclusions and Inferences The pylorus seems to act as a sphincter at low distention but when further dilated starts acting as a pump. Fully distended the pyloric motility disappears and the pressure remains high, suggesting that a stent with high‐radial force might show less migration. Little is known about the pyloric response to the placement of a metal stent. This study investigates the pyloric response to distention with the EndoFlip balloon, mimicking stent‐treatment. When an elongated balloon is distended in the pylorus with a low volume, the pylorus acts as a sphincter, and with increasing volumes, it starts acting more as a peristaltic pump. At maximum balloon volume, pylorus seems fully distended lacking motility waves. A stent placed over pylorus should probably have a high‐radial force to cause dilatation and reduce pyloric contractions, diminishing the risk of stent migration.