An ambulant porcine model of acid reflux used to evaluate endoscopic gastroplasty

Background-There is a lack of suitable models for testing of therapeutic pr ocedures for gastro-oesophageal reflux disease. Endoscopic sewing methods m ight allow the development of a new less invasive surgical approach to trea tment of gastrointestinal disorders. Aims-To develop an animal model of gastro-oesophageal reflux for testing th e efficacy of a new antireflux procedure, endoscopic gastroplasty, performe d at flexible endoscopy without laparotomy or laparoscopy. Methods-At endoscopy a pH sensitive radiotelemetry capsule was sewn to the oesophageal wall, 5 cm above the lower oesophageal sphincter, in six large white pigs. Ambulant pH recordings (48-96 hours; total 447 hours) were obta ined. The median distal oesophageal pH was 6.8 (range 6.4-7.3); pH was less than 4 for 9.3% of the time. After one week, endoscopic gastroplasty was p erformed by placing sutures below the gastro-oesophageal junction, forming a neo-oesophagus of 1-2 cm in length. Postoperative manometry and pH record ings (24-96 hours; total 344 hours) were carried out. Results-Following gastroplasty, the median sphincter pressure increased sig nificantly from 3 to 6 mm Hg and in length from 3 to 3.75 cm. The median ti me pH was less than 4 decreased significantly from 9.3% to 0.2%. Conclusions-These are the first long term measurements of oesophageal pH in ambulant pigs. The finding of spontaneous reflux suggested a model for stu dying treatments of reflux. Endoscopic gastroplasty increased sphincter pre ssure and length and decreased acid reflux.