Prospective Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Pharmacol Ther. Feb 6, 2016; 7(1): 145-155
Published online Feb 6, 2016. doi: 10.4292/wjgpt.v7.i1.145
Effect of electrical stimulation of the lower esophageal sphincter in gastroesophageal reflux disease patients refractory to proton pump inhibitors
Edy Soffer, Leonardo Rodríguez, Patricia Rodriguez, Beatriz Gómez, Manoel G Neto, Michael D Crowell
Edy Soffer, Division of Gastroenterology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, United States
Leonardo Rodríguez, Patricia Rodriguez, Beatriz Gómez, Surgery, CCO Centro Clínico de Obesidad, Diabetes y Reflujo, Las Condes, Santiago 7550000, Chile
Manoel G Neto, Surgery, Gastro Obeso Center, Bela Vista, São Paolo 1308-000, Brazil
Michael D Crowell, Department of Gastroenterology and Hepatology, Mayo Clinic, Scottsdale, AZ 85259, United States
Author contributions: Soffer E acquisition of data; analysis and interpretation of data; drafting of the manuscript; critical revision of the manuscript for important intellectual content; statistical analysis; Rodríguez L analysis and interpretation of data; drafting of the manuscript; critical revision of the manuscript for important intellectual content; statistical analysis; obtained funding; technical, or material support; study supervision); Rodriguez P acquisition of data; analysis and interpretation of data; critical revision of the manuscript for important intellectual content; technical or material support; Gómez B acquisition of data; analysis and interpretation of data; critical revision of the manuscript for important intellectual content; technical or material support; Neto MG acquisition of data; analysis and interpretation of data; critical revision of the manuscript for important intellectual content; technical or material support; Crowell MD study concept and design; analysis and interpretation of data; drafting of the manuscript; critical revision of the manuscript for important intellectual content; statistical analysis; technical, or material support.
Institutional review board statement: The study was approved by the ethics committee of the eastern metropolitan health service in Santiago, Chile “Comite de Etica Cientifico, Servicio de Salud Metropolitano Oriente”.
Clinical trial registration statement: The study was registered in www.clinicaltrials.gov. The registration identification is NCT01578642.
Informed consent statement: All study participants provided informed written consent prior to study enrollment.
Conflict-of-interest statement: EndoStim Inc., St. Louis, MO, United States provided funding for the trial. The sponsor helped with monitoring, collection and tabulation of the data. The data analyses were independently performed by the investigators. EndoStim Inc, St. Louis, MO, United States provided funding for the trial. Professor Michael D Crowell is a consultant for EndoStim Inc. and the chair of its data monitoring committee. Professor Edy Soffer is a shareholder in EndoStim Inc. Remaining study authors or their immediate family have no financial relationship with the sponsor that would constitute a conflict of interest.
Data sharing statement: Technical appendix, statistical code, and dataset available from the corresponding author at edy.soffer@med.usc.edu. Participants gave informed consent for data sharing
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Edy Soffer, MD, Division of Gastroenterology, Keck School of Medicine, University of Southern California, 1510 San Pablo Street, HCC One, Los Angeles, CA 90033, United States. esoffer@usc.edu
Telephone: +1-323-4425833
Received: July 21, 2015
Peer-review started: July 30, 2015
First decision: September 14, 2015
Revised: October 9, 2015
Accepted: December 3, 2015
Article in press: December 4, 2015
Published online: February 6, 2016
Abstract

AIM: To evaluate the efficacy of lower esophageal sphincter (LES)-electrical stimulation therapy (EST) in a subgroup of patients that reported only partial response to proton pump inhibitors (PPIs) therapy, compared to a group of patient with complete response.

METHODS: Bipolar stitch electrodes were laparoscopically placed in the LES and connected to an implantable pulse generator (EndoStim BV, the Hague, the Netherlands), placed subcutaneously in the anterior abdominal wall. Stimulation at 20 Hz, 215 μsec, 3-8 mAmp in 30 min sessions was delivered starting on day 1 post-implant. Patients were evaluated using gastroesophageal reflux disease (GERD)-HRQL, symptom diaries; esophageal pH and esophageal manometry before and up to 24 mo after therapy and results were compared between partial and complete responders.

RESULTS: Twenty-three patients with GERD on LES-EST were enrolled and received continuous per-protocol stimulation through 12 mo and 21 patients completed 24 mo of therapy. Of the 23 patients, 16 (8 male, mean age 52.1 ± 12 years) had incomplete response to PPIs prior to LES-EST, while 7 patients (5 male, mean age 52.7 ± 4.7) had complete response to PPIs. In the sub-group with incomplete response to PPIs, median (IQR) composite GERD-HRQL score improved significantly from 9.5 (9.0-10.0) at baseline on-PPI and 24.0 (20.8-26.3) at baseline off-PPI to 2.5 (0.0-4.0) at 12-mo and 0.0 (0.0-2.5) at 24-mo follow-up (P < 0.05 compared to on-and off-PPI at baseline). Median (IQR) % 24-h esophageal pH < 4.0 at baseline in this sub-group improved significantly from 9.8% (7.8-11.5) at baseline to 3.0% (1.9-6.3) at 12 mo (P < 0.001) and 4.6% (2.0-5.8) at 24 mo follow-up (P < 0.01). At their 24-mo follow-up, 9/11 patients in this sub-group were completely free of PPI use. These results were comparable to the sub-group that reported complete response to PPI therapy at baseline. No unanticipated implantation or stimulation-related adverse events, or any untoward sensation due to stimulation were reported in either group and LES-EST was safely tolerated by both groups.

CONCLUSION: LES-EST is safe and effective in controlling symptoms and esophageal acid exposure in GERD patients with incomplete response to PPIs. These results were comparable to those observed PPI responders.

Keywords: Refractory gastroesophageal reflux disease, Gastroesophageal reflux, Electrical stimulation, Lower esophageal sphincter, Proton pump inhibitors

Core tip: Proton pump Inhibitors (PPI) are the main medical therapy for gastroesophageal reflux disease (GERD). However, 30%-40% of patients are unsatisfied with PPI therapy. Traditional antireflux surgery is effective but is associated with adverse effects and its numbers are declining, resulting in an unmet need for alternative therapies. Electrical stimulation therapy (EST) of the LES has been shown to significantly improve GERD symptoms and esophageal acid exposure in patients with GERD. The current study shows that patients who respond to PPI but are concerned about the drugs, as well as those with incomplete response to PPI respond equally to EST of the LES.