Electrical Stimulation Therapy (EST) of the Lower Esophageal Sphincter (LES) Is Successful in Treating GERD – Final Results of Open-label Prospective Trial

Leonardo Rodríguez, MD, Patricia Rodríguez, RN, Beatriz Gómez, BSc, Juan C Ayala, MD, Jorge Saba, MD, Alberto Perez-castilla, MD, Manoel. G Neto, MD. Surgery, CCO OBESIDAD Y DIABETES, Santiago, Chile


Background: Improvement in LES pressures using EST was previously demonstrated in animals and GERD patients using temporary endoscopic and laparoscopic leads.
Aims: The aim of this prospective open-label human trial was to study the safety and efficacy of long-term LES-EST using a laparoscopically implanted neurostimulator in GERD patients.
Methods: GERD patients at least partially responsive to proton pump inhibitors (PPI) and had off-PPI GERD HRQL>20, basal LES end-expiratory pressures (EEP) of 5-15 mmHg, % 24 hour esophageal pH<4.0 for >5%, hiatal hernia < 3cm and esophagitis < LA Grade C were included in the trial. Bipolar stitch electrodes were laparoscopically placed in the LES and an implantable pulse generator (EndoStim Inc., St. Louis, MO, USA) was placed subcutaneously in the anterior abdominal wall. EST at 20 Hz, 200usec, 3-8mAmp in 30 minutes sessions was delivered starting on day 1 post-implant. The sessions were delivered pre-meal and at night. Patients were evaluated using GERD-HRQL, symptom diaries and SF-12 at baseline and every month for six months thereafter and underwent esophageal pH at 0, 1, 3 and months and high resolution manometry testing at 0, 1, 3 months. Stimulation sessions were optimized based on residual symptoms and lead impedance at follow-up.
Results: Twenty-four patients [mean age (sd) = 53 (12) years; men=14] were successfully implanted and have completed their 6 month evaluation. 

Effect of LES-EST on Patient symptoms, Esophageal pH and LES pressure
 BaselineMonth 3Month 6
Mean GERD-HRQL off-PPI23.7 (3.5)4.2 (3.3)2.5 (3.1)
Median % 24-hour Esophageal pH<4.011.1 (6.5)7.5 (4.5)4.9 (5.3)
Mean LES End Expiratory Pressure8.6 (0.5)15.4 (1.4)No HRM

(p<0.001 for all comparisons vs. baseline)

There was a significant reduction in number of days patient reported heartburn (45% vs. 91%, p<0.001) and regurgitation (17% vs. 69%; p<0.001) on EST compared to off-PPI. At their last follow-up all patients were off their daily PPI and had significantly better GERD-HRQL on LES-EST compared to on-PPI [2.5 (3.1) vs. 9.8 (6.3); p<0.001]. There was a significant improvement in both physical and mental scores on SF-12 quality of life measurement at follow-up compared to both on and off PPI scores (p<0.01). There were no implantation- or stimulation-related unanticipated adverse events, or untoward sensation due to stimulation. The swallowing function was also unaffected by EST.
Conclusion: During the long term follow-up of 6 months, LES-EST was safe and effective for treating patients with GERD. There was a significant and sustained improvement in symptoms, esophageal acid exposure and LES pressures. Further, LES-EST can be optimized to individual patient needs. All patients had received significant clinical benefit from LES-EST and the trial has been extended to two year. One year follow-up results of this trial will be available for presentation in March 2012.

Session Number: SS18 – Foregut
Program Number: S095

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