Electrical Stimulation Therapy (EST) Significantly and Consistently Increases Lower Esophageal Sphincter (LES) Pressure in GERD Patients

Abstract

Purpose: EST can increase LES pressures (LESP) in animals. To study the safety and effect of EST on LESP and esophageal function in GERD patients. Methods: Thirteen patients with GERD responsive to PPI, increased esophageal acid exposure off medications, basal LESP >5 mmHg, hiatal hernia <2 cm and esophagitis < LA Grade C were included in the study. Endoscopic (Endo) group (n=6; all men)-Temporary pacer lead (Medtronic 6416, 200 cm) were placed in the LES. The lead was secured to the esophagus with endoclips and exteriorized nasally. Laparoscopic (Lap) group (n=7; 1M, 6F) - Bipolar stitch lead (CCC, Uruguay) were placed in the LES during an elective lap cholecystectomy, and exteriorized through the abdominal wall. EST delivered various stimulation algorithms (Pulse width =250 μsec, 3 msec and 300 msec; pulse amplitude=5 to 15mAmp and pulse frequency=5 cps and 20 Hz) per protocol. EST was delivered in 20 minute sessions followed by a 20 minute washout or till LESP returned to baseline, whichever was longer. Manometery was performed pre-, end- and post-EST. Symptoms of heartburn, chest pain, abdominal pain and dysphagia pre-, during and post-EST and 7-days post-EST were recorded. Continuous cardiac monitoring was performed during and post-EST. LESP data pre-, end- and post-EST were compared using a t-test (paired, 2-tailed). Results: Endo Group -5 patients completed the EST study 6-12 h post-implant (the first patient had a premature lead dislodgement). EST, using various algorithms, resulted in a significant and sustained increase in LESP in all patients (5/5), from 11.4+/-4.9 mm Hg at baseline to 37.1+/-17.2 mm Hg at end EST (p<0.05) and 20.1+/-11.6 mm Hg during post-EST period (p<0.01). Lap Group -All (7/7) patients received per-protocol EST 24h post lead implant and had a significant and sustained increase in LESP. Optimal EST parameters resulted in an increase in mean LESP from 10.7+/-2.1 mm Hg pre-EST to 18.4+/-2.2 mm Hg at end-EST (p<0.01) and 24.0+/-2.6 mm Hg during post-EST period (p<0.001). Swallow induced LES relaxation was not affected, esophageal body pressures were improved, and post-swallow LES pressure was enhanced with EST in all patients and in both groups. In the Lap group, 2 patients had an abnormal sensation with EST at amplitudes of 13-15 mAmp which resolved at amplitudes < 13mAmp. There were no adverse events or any cardiac rhythm abnormalities with EST in either group. Conclusion: In GERD patients, EST results in a significant, consistent and sustained increase in LES pressure without effecting patients' swallow function or causing any adverse symptoms or cardiac rhythm disturbances. EST may offer a novel therapy to patients with GERD. Disclosure: Dr Virender K Sharma - Consultant, Equity Interest - EndoStim Inc. Dr Edy Soffer - Consultant, Equity Interest - EndoStim Inc. This research was supported by an industry grant from EndoStim, Inc.