Cutaneous Electrogastrography (EGG)
DESCRIPTION
Electrogastrography (EGG) describes the recording and interpretation of electrical activity of the stomach. Recordings can be made from the gastrointestinal mucosa, serosa, or skin surface. Because of its ease of use, cutaneous EGG has been used frequently and is the focus of this policy.
The electrical activity of the stomach can be subdivided into two general categories: electrical control activity (ECA) and electrical response activity (ERA). ECA is characterized by regularly recurring electrical potentials, originating in the gastric pacemaker located in the corpus of the stomach and sweeping in an annular band with increasing velocity toward the pylorus. ECA is not associated with contractions of the stomach unless coupled with action potentials, referred to as ERA. The usual practice is to record several cutaneous EGG signals from various standardized positions on the abdominal wall and to select the one with the highest amplitude for further analysis. Nonetheless, the recorded signal is relatively weak and difficult to distinguish from the surrounding background "noise" related to unwanted signals, such as cardiac, respiratory, duodenal, and colonic electrical activity. For this reason, direct visual analysis of the EGG signals is problematic. Various methods of filtering out background noise and automated analysis have been developed; running spectral analysis is most common. The EGG is usually evaluated in terms of changes in the EGG amplitude and frequency. Deviations from the normal frequency of 3 cycles per minute may be referred to as brady- or tachyarrhythmia.
The use of EGG has been most widely studied in patients with gastroparesis and functional dyspepsia. Gastroparesis is defined as a chronic disorder of gastric motility as evidenced by delayed gastric emptying of a solid meal. Symptoms include bloating, distension, nausea, and vomiting. When severe and chronic, gastroparesis can be associated with dehydration, poor nutritional status, and poor glycemic control in diabetics. While most commonly associated with diabetes, gastroparesis is also found in chronic pseudo-obstruction, connective tissue disorders, Parkinson's disease, and psychological pathology. Functional dyspepsia is an enigmatic disorder characterized by persistent symptoms of abdominal discomfort with no identifiable etiology, including gastric emptying. In this setting, disorders in gastric motility may be considered. Treatment of gastric motility disorders, typically include the use of prokinetic agents, such as cisapride, domperidone, or metoclopramide.
Scintigraphic gastric emptying is considered the gold standard test for evaluating gastroparesis. The test involves the ingestion of a solid meal with 99-technetium added. Serial scintigraphic measurements are then performed every 20 minutes for 2-3 hours after the meal. Delayed gastric emptying is diagnosed if more than 50% of the radio-labelled food is retained at the end of the study period. While gastric emptying evaluates the efficiency of gastric emptying, EGG focuses on the underlying myoelectrical activity.
POLICY
Cutaneous electrogastrography for the treatment of gastric motility disorders is considered investigational.
IMPORTANT REMINDER
We develop Medical Policies to provide guidance to Members and Providers. This Medical Policy relates only to the services or supplies described in it. The existence of a Medical Policy is not an authorization, certification, explanation of benefits or a contract for the service (or supply) that is referenced in the Medical Policy. For a determination of the benefits that a Member is entitled to receive under his or her health plan, the Member's health plan must be reviewed. If there is a conflict between the Medical Policy and a health plan, the express terms of the health plan will govern.
ADDITIONAL INFORMATION
The published literature suggests that EGG is primarily used as a research tool in patients with a variety of disorders. Other studies continue to focus on the technical performance of the test, including the use of multichannel recording compared to single channel recording. No study was identified that elucidated the diagnostic performance of EGG in different populations of patients or how this information could be used to benefit patient management.
In 2001, the American Gastroenterological Association published a medical position statement on nausea and vomiting, which offered the following conclusion:
"Although well-documented disorders of enteric nerve and muscle such as the pseudo-obstruction syndrome may result in nausea and vomiting, the role of gastrointestinal dysmotility and gastroparesis, in particular, in the patient with isolated chronic nausea and vomiting remains unclear. Although gastroparesis is common among patients in this category, its primacy remains in dispute, and the interrelationships between such entities as functional and psychogenic vomiting, idiopathic gastroparesis, and functional dyspepsia remain unclear. For these same reasons, the place of such tests of motor function as gastric emptying studies, electrogastrography, and manometry have not been defined, and the yield of such diagnostic studies has not been adequately compared with a therapeutic trial of an antiemetic and/or prokinetic agents."
SOURCES
Abid, S., & Lindberg, G. (2007). Electrogastrography: Poor correlation with antro-duodenal manometry and doubtful clinical usefulness in adults. World Journal of Gastroenterology, 13 (38), 5101-5107. (Level 2 Evidence - Independent study)
American Gastroenterological Association. (2001). American Gastroenterological Association medical position statement: Nausea and vomiting. Retrieved June 1, 2010 from http://download.journals.elsevierhealth.com/pdfs/journals/0016-5085/PIIS0016508501703228.pdf.
American Gastroenterological Association. (2001, January). AGA technical review on nausea and vomiting. Gastroenterology, 120 (1), 263-286.
American Gastroenterological Association. (2004). American Gastroenterological Association medical position statement: Diagnosis and treatment of gastroparesis. Retrieved June 1, 2010 from http://download.journals.elsevierhealth.com/pdfs/journals/0016-5085/PIIS0016508504016336.pdf.
American Gastroenterological Association. (2004, November). American Gastroenterological Association technical review on the diagnosis and treatment of gastroparesis. Gastroenterology, 127 (5), 1592-1622.
BlueCross BlueShield Association. Medical Policy Reference Manual. (6:2008). Cutaneous Electrogastrography (EGG) (2.01.34). Retrieved June 1, 2010 from BlueWeb. (23 articles and/or guidelines reviewed)
Chen, C. L., Hu, C. T., Lin, H. H., & Yi, C. H. (2006). Clinical utility of electrogastrography and the water load test in patients with upper gastrointestinal symptoms. Journal of Smooth Muscle Research, 42 (5), 149-157.
Code of Federal Regulations. Title 21, Volume 8. (2009, April). Section 876.1735. Electrogastrography system. Retrieved June 1, 2010 from http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfCFR/CFRSearch.cfm?fr=876.1735.
Feldman, M., Friedman, L. S., & Brandt, L. J. (Eds.) (2010). Sleisenger & Fordtran's Gastrointestinal and Liver Disease (9th ed., Chapter 14). Philadelphia: W. B. Saunders.
Hasler, W. (2007). Gastroparesis: Symptoms, evaluation, and treatment. Gastroenterology Clinics of North America, 36 (3), 619-647.
ORIGINAL EFFECTIVE DATE: 3/8/2007
MOST RECENT REVIEW DATE: 7/22/2010
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