The use of SmartPill for gastric monitoring

Abstract

Testing to define delayed gastric emptying is required to diagnose gastroparesis; rapid emptying is found in other patients. Commonly performed methods of gastric emptying testing include scintigraphy and breath testing. The SmartPill wireless motility capsule (WMC) system is US FDA-approved for evaluating suspected delayed emptying in gastroparesis and functional dyspepsia. The device measures transit in the stomach, small intestine, and colon by detecting characteristic pH transitions; and quantifies pressure waves in each gut region. WMC gastric emptying times correlate with scintigraphic measures. Incremental benefits of WMC testing in patients with suspected gastroparesis include delineation of pressure abnormalities and small intestinal and colonic transit delays. Acceptance of trial data confirming usefulness of WMC testing in suspected gastric motor disorders has been hampered by small sample sizes and design limitations. Ongoing multicenter studies will validate the utility of WMC methods in patients with suspected gastroparesis and other upper gastrointestinal motor disorders.

Keywords::

• diabetes mellitus
• dyspepsia
• gastric contraction
• gastric emptying
• gastrointestinal motility
• gastroparesis
• nausea and vomiting

Acknowledgements

W Hasler thanks J Semler, consultant at Given Imaging, Inc., for providing updated WMC complication data from post marketing reports for this paper.

Financial & competing interests disclosure

W Hasler receives research funding from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) (grant U01DK073983) as part of the Gastroparesis Clinical Research Consortium. He also receives funding from Given Imaging, Inc. for a clinical trial validating the SmartPill recording system as a diagnostic test for delayed gastric emptying. In the past 24 months, W Hasler has been a consultant to Janssen Pharmaceuticals, Inc., Novartis Pharmaceuticals, GSK and Salix Pharmaceuticals, Inc. The author has no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Diagnosis of gastroparesis relies on demonstration of delayed gastric emptying in patients with symptoms of gastric retention including nausea, vomiting, postprandial fullness, early satiety, bloating, distention and upper abdominal pain or discomfort. Disorders of rapid gastric emptying also have been described, but are less well characterized.

• Most individuals undergo either gastric scintigraphy (in the USA) or gastric emptying breath testing (in some European countries) to verify delayed gastric emptying; however, concerns about standardization of testing methodologies and interpretation have been raised for these techniques.

• The SmartPill Wireless Motility Capsule (WMC) method quantifies gastric emptying by detecting characteristic pH increases as the capsule is expelled from the acidic stomach into the more neutral duodenum; a WMC gastric emptying time >5 h is considered diagnostic of gastroparesis in the appropriate clinical setting.

• One prospective study of concurrent WMC and scintigraphy performance reported good correlation of test positivity and negativity of the two methods. This investigation and other published retrospective studies did suggest additional diagnostic gain of WMC testing compared with scintigraphy.

• Studies of the clinical utility of WMC testing in suspected gastroparesis are limited by small sample sizes and issues related to patient subsets recruited and study design. A comprehensive systematic review concluded there is low strength of evidence that WMC testing alone is comparable with gastric scintigraphy and low strength of evidence that WMC testing has utility as an add-on test to other modalities.

• WMC methods offer additional abilities to detect generalized transit delays and intraluminal pressure abnormalities.

• Complications of WMC testing are uncommon, but include rare cases of capsule retention.

• Ongoing prospective, multicenter studies comparing WMC parameters of gastric transit and pressure with standardized gastric scintigraphy methods and other tests of gastric and extragastric function will refine our understanding of the clinical utility of WMC testing in patients with suspected gastric dysmotility syndromes.

Notes