Appendix FDescription of Endoscopic Treatments and Preliminary Findings

Publication Details

Description of Endoscopic Treatments and Preliminary Findings

As we did our systematic literature search of MEDLINE in February of 2005, there has been much information on endoscopic treatments presented either in abstracts or society meetings in the last four months. The following is a distillation of current information regarding this topic.

Endoscopic treatments

Three endoscopic therapies are currently available for use in the United States. A fourth procedure, Enteryx ™, was voluntarily recalled from the market due to safety concerns during final preparation of this report. The physiologic basis for improvement in symptoms or objective measures of GERD is unclear, although several mechanisms have been proposed for each technique.

  • The Stretta™ procedure (Curon Medical, Freemont, CA) involves application of radiofrequency energy to the lower esophageal sphincter. Proposed mechanisms whereby radiofrequency energy might lead to improvement in GERD include a reduction in the number of transient lower esophageal sphincter relaxations and a reduction in the distensibility of the gastroesophageal junction.1
  • Enteryx™ involves injection of a biopolymer (Enteryx™, Boston Scientific, Natick, MA) into the lower esophageal sphincter. Enteryx™ contains 8 percent ethylene vinyl alcohol copolymer (EVOH) dissolved in dimethyl sulfoxide (DMSO). The DMSO diffusate results in solidification of the EVOH, which forms a spongy solid mass. The precise mechanisms whereby it improves GERD are not understood, although it is hypothesized that the physical properties of the implant might augment the lower esophageal sphincter mechanism.2.
  • EndoCinch™ Suturing System (Bard, Murray Hill, NJ) involves creation of plication in the region of the gastric cardia using a device that allows for sutures to be placed endoscopically. The stitches typically penetrate only as far as the submucosa. Preclinical studies suggested that the sutures increase lower esophageal sphincter pressure.3, 4
  • NDO Plicator™ (NDO Plicator ™, NDO Surgical, Mansfield, MA) also involves creation of a plication in the region of the gastric cardia. However, unlike Endocinch™, the device allows for a transmural plication. Animal studies suggested that plication increases the threshold of intragastric pressure needed to cause a reflux episode.5
  • Other devices continue to be developed but are not included in this report. One of the devices for which clinical trials are emerging rapidly is the “Gatekeeper™ reflux repair system (Medtronics, Minneapolis, MN), which involves implantation of a self-expanding bioprosthesis into the lower esophageal sphincter.6, 7

Preliminary findings and studies in progress

Our literature search identified only two sham-controlled studies that have been published in final form (one for Stretta8 and the other for Enteryx™9). Sham controlled trials for the other procedures are in progress but only interim results have been presented in preliminary form.1012 A second, multicenter, sham-controlled trial of the Enteryx™ procedure is ongoing.13None of the studies directly compared endoscopic therapy to continued (or intensified) medical therapy or compared one endoscopic procedure to another. At least one comparison of EndoCinch™ with Enteryx™ is ongoing and has been presented in preliminary form.14 The preliminary results show similar efficacy on symptoms, quality of life and pH status.

A benefit on esophageal pH exposure compared with sham could not be demonstrated for either Enteryx™ or Stretta™. A preliminary report of a United States Multicenter sham-controlled trial of Enteryx™ suggests a benefit on pH, but the study has not yet been completed.13

The preliminary results of one ongoing sham-controlled trials of Endocinch™ raise additional concerns related to its efficacy when considered in the context of two earlier reports showing loss of sutures in the majority of patients.15, 16 This study reported a similar proportion of patients relapsed and there were no differences in esophageal pH exposure between sham and Endocinch™ treated patients after one year.10 A preliminary report of another sham-controlled trial found significant improvement in heartburn frequency but not severity, regurgitation, quality of life or the ability to discontinue all anti-secretory therapy after three months compared with the sham procedure.11

A preliminary report of 46 patients who had participated in a United States open label trial of Enteryx™17 found that two-thirds had sustained symptom control and reduction or discontinuation of PPI use for up to 36 months.13 However, the original study included 144 patients and the disposition of the remaining 98 patients is unclear.