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GASTROENTEROLOGY & ENDOSCOPY NEWS • MAY 2013
Electrical Stimulation Demonstrates Encouraging Results In Patients With GERD, Gastroparesis BY TED BOSWORTH LAS VEGAS—Gastrointestinal (GI) diseases that involve disturbed or inadequate muscle contraction have proven difficult to treat pharmacologically. Now, two separate attempts to employ exogenously delivered electrical stimulation have yielded results sufficiently encouraging that viable clinical devices are in development. In patients with gastroesophageal reflux disease (GERD), the control of esophageal acid exposure with an implantable device that produces contraction of the lower esophageal sphincter (LES) appears impressive based on 12 months of followup. And in diabetic gastroparesis, a wearable device delivering stimulation to the surface of the skin with a purported effect on motility was able to demonstratte a significant reduction in symptoms relative to a sham device.
Clinic, Hospital Indisa, Santiago, Chile, who performed the surgical procedure in all patients. At the end of 12 months, no patient remained on daily PPI therapy, and 77% of patients reported either normalization or greater than 50% reduction in distal acid exposure over 24 hours. There were no complications related to the implanted device or to the electrical stimulation. No abnormalities of were reported, and no dysphagia was observed on manometry. “The evidence that the device continues to function after 12 months as it did when first implanted suggests that it is a viable solution for patients who are not adequately controlled on PPIs and want to avoid antireflux surgery,” Dr. Soffer said. In addition to the final one-year results, larger studies now under way will be important to confirming the viability of this therapy.
Gastroparesis
The second evaluation was substantially different in concept, p , even if the ability to use electrrical stimulation to treat aG GI disease was the same. In n this study, chronic electrical stimulation GERD was delivered to two In studies of electrical stimulaation in acupuncture points patients with GERD, the control off sympthat have previously toms at 12 months was similar to control been associated with EndoStim, a medical device developed to treat gastroat three and six months, which su uggests improving nausea and esophageal reflux disease through electrical stimulation, that electrical stimulation may noot share vomiting. The stimuis not currently approved in the United States. the diminishing benefits associatted lation device, described Images courtesy of EndoStim with previous endoscopic strategiees aas the size of a watch, directed at tightening the LES. was worn on the wrist or w On the basis of objective tests, leg. The leads did not inter“electrical stimulation of the LES fere with daily activities. is associated with normalizaEighteen patients with E tion of both proximal and disdiab betes, all of whom had tal esophageal acid exposure,” refraactory gastroparesis at reported Edy Soffer, MD, directhe time of study enrolltor, GI Motility Program, Unimen nt, served as their own versity of Southern California, conttrols. The crossover Los Angeles. Participating in a desiggn included four weeks ‘Electrical press conference at the annual of electrical stimulation stimulation meeting of the American Coland four weeks of sham lege of Gastroenterology (ACG), stim mulation applied in a of the LES where results of the the pilot stud dy rand dom order. The devices is associated were presented, Dr. Soffer emph haweree worn for two hours with normalization sized that electrical stimulation soo far afterr lunch and dinner. The has not been associated with the side effeccts were evaluated with of both proximal and effects of many of the endoscopic antireflux the nine-question Gastrodistal esophageal devices or with antireflux surgery. pareesis Cardinal Symptom The LES stimulator device, likee a cardiac paceIndeex (GCSI) and the acid exposure.’ maker, is implanted under anesthesia i in i a subcutaneous b 36-question Short Form 36 —Edy Soffer, MD pocket. Two leads are attached to the LES to deliver (SF-36). Each was comelectrical pulses that cause the muscle to contract. In pleted weekly. this study, electrical stimulation was delivered at 20 Hz, quality of life. In the short term of the pilot study, “Five of nine gastroparesis symptoms were improved 215 µs, 3-8 mA in 30-minute sessions timed to coin- improvements in LES pressure and reductions in esoph- over the four weeks that patients used the electrical stimcide with peak periods of reflux events, but the electrical ageal pH tracked with a reduction in GERD symptoms. ulation device,” reported Richard McCallum, MD, propulses can be individualized. One-year interim results with 23 patients were presented fessor and founding chairman, Department of Medicine, The initial pilot study included 24 patients with at the ACG meeting. University of Texas Medical Branch, Galveston, who GERD. Most had experienced only a partial response The most notable finding was that all of the effects presented the findings at the ACG meeting. “No signifiwith proton pump inhibitor (PPI) therapy. At baseline, observed at the end of the short term of the pilot study cant improvement was associated with the sham device.” all patients had elevated 24-hour esophageal acid levels, persisted and improved at 12 months, according to The improvements included a 31.1% reduction in as well as impairments in measures of GERD-related Leonardo Rodríguez, MD, of the Obesity and Diabetes see Electrical Stimulation, page 48