image

Patients suffering from symptoms suggestive of gastroparesis and chronic constipation frequently present with vague, nonspecific, and overlapping symptoms, often making it a challenge to provide a unifying diagnosis. The wireless motility capsule (WMC) represents one of the most recent testing modalities in this patient population and enables the simultaneous assessment of gastric, small bowel, and colonic transit.1 Recent data have indicated that WMC testing defines transit delays in gastroparesis and chronic constipation—independent of symptom presentation—and provides new diagnoses in more than 50% of cases.1 These diagnoses are often different from those determined by the conventional tests in part due to the ability of the WMC to provide a full GI tract transit profile.1 An orally ingested, nondigestible, data recording capsule that can measure temperature, pressure, and pH, the WMC assesses transit times through the entire GI tract without the need for radiation exposure or specialized center visits.1-3

“A patient presents with nausea, vomiting, abdominal pain, and constipation—the body has a fixed number of ways of expressing itself, which leaves a multitude of possible causes. It is frequently difficult, especially in patients with moderate to severe symptoms, to know exactly where the disease is coming from, and if there is a defect, based purely on their history,” said Braden Kuo, MD, director of the Neuroenteric Research Laboratory at Massachusetts General Hospital in Boston, Massachusetts. “Even if you think it is in the stomach, is it purely in the stomach or could it involve other areas of the GI tract, which could affect your diagnosis and how you treat the patient?”

Once clinicians rule out organic conditions in the GI tract, such as ulcers or cancer, using endoscopy and other structural testing modalities, WMC testing is a valuable tool for diagnosing motility disorders, including gastroparesis and slow transit constipation, according to Dr. Kuo. He added that even if WMC testing shows no abnormalities, the clinician still can glean valuable information from the test. “If the test comes back normal, it allows us to move more confidently into the next area, checking for problems with nerve endings, such as visceral hypersensitivity, that could be driving the patient’s symptomatology,” Dr. Kuo said.

Dr. Kuo also noted that WMC testing measures transit times while the patient is ambulatory, whereas other methods measure transit while the patient is stationary in the hospital setting.2,4-6 Henry Parkman, MD, director of the GI Motility Laboratory at the Lewis Katz School of Medicine at Temple University, in Philadelphia, Pennsylvania, agreed with Dr. Kuo that WMC can be a powerful tool for diagnosing patients with mixed symptom presentation. “WMC testing is great if the patient has both upper and lower GI symptoms. You might have a patient who says they have some fullness and nausea, but they are also constipated. Is it delayed stomach emptying, or is it delayed colonic transit, or is it a mixture of both?”

Before WMC testing, assessing transit times throughout the entire GI tract was difficult and costly, potentially involving multiple tests and significant radiation exposure, according to Richard Saad, MD, associate professor and a specialist in gastroenterology and internal medicine at the University of Michigan in Ann Arbor, Michigan. A breath test also is available, and has been found to accurately assess gastric emptying, exhibiting results concordant with those of gastric emptying scintigraphy7; however, it is an indirect measure, and like most other tests, evaluates transit through only one part of the GI tract.8

image
Wireless motility capsule ingestible capsule hardware.
Image courtesy of Medtronic.

“In the past, if you wanted to evaluate somebody for a global motility problem, you had to order whole gut scintigraphy. Generally speaking, the patient has to go to one of a very few specialized nuclear medicine facilities to have that test done, and return to a stationary gamma camera several times over several days,” Dr. Saad said.6 “Or, you could do 3 separate studies: the gastric emptying scintigraphy to assess gastric emptying; the small-bowel follow-through, which is a fluoroscopic test capable of assessing small bowel transit time; and a colonic transit test, also known as a radiopaque marker study.”

Dr. Saad noted that “often, these tests cannot be completed at the same time and would require a patient to return to the hospital more than once. Also, all 3 tests result in some radiation exposure. With the WMC, a patient can simply ingest the capsule, wear a receiver, and return the device in 5 days. The acquired data, with one pass, enables the clinician to determine a gastric emptying time, a small bowel transit time, and a colon transit time.”

Reproducibility is another advantage offered by WMC testing, according to Michael Cline, DO, a gastroenterologist at the Cleveland Clinic Twinsburg Family Health and Surgery Center in Twinsburg, Ohio. “If you conduct the WMC tests repeatedly, your results will be consistent,” Dr. Cline said. “We have documented that at our clinic with approximately 16 patients who have had to do 2 tests, and the numbers were within about 2 minutes of each other.” Dr. Cline uses WMC testing at the Cleveland Clinic in addition to his private practice. “There is nothing else that compares to it in terms of availability, and nothing that gives you that much information with one test,” he said.

Dr. Cline and his colleagues at the Cleveland Clinic retrospectively compared the results of WMC testing in 118 diabetic patients with those of 244 idiopathic patients, all of whom presented with upper GI symptoms and had prior documentation of delayed gastric emptying.9 The prevalence of generalized delay was similar at 36% and 30%, respectively. Also, diabetic patients were nearly 3 times as likely (42% vs 15%) to have isolated gastric delay as idiopathic patients.9 Dr. Cline and his colleagues hope to use WMC testing to characterize transit patterns in other diseases: He is currently collecting data on transit times in various connective tissue diseases, including Ehlers-Danlos syndrome, rheumatoid arthritis, and lupus, to determine whether they have identifiable transit patterns through the GI tract. Please see the case study for a typical example of how WMC testing can influence patient diagnosis and treatment.

WMC testing is not without limitations. The limitations can include, but are not limited to the inability of the patient to swallow the capsule, capsule retention, software malfunction, failure of the WMC to transmit data, and failure of the receiver to record or download data. A variety of medications altering pH or bowel motility also can affect the accuracy of the transit data.3 “Despite these limitations, the WMC is the only testing modality that you can administer in an office setting that does not result in any radiation exposure, and that can measure the transit of the stomach, small bowel, and colon,” Dr. Saad said. “The greatest advantage to the WMC is its ability to evaluate a patient who is suspected of having a global motility disorder, such as gastroparesis and slow transit constipation, in the ambulatory setting.”

References

  1. Kuo B, Maneerattanaporn M, Lee AA, et al. Dig Dis Sci. 2011;56(10):2928-2938.
  2. Rao SS, Camilleri M, Hasler WL, et al. Neurogastroenterol Motil. 2011;23(1):8-23.
  3. Saad RJ, Hasler WL. Gastroenterol Hepatol (N Y). 2011;7(12):795-804.
  4. Rao SS, Mysore K, Attaluri A, et al. J Clin Gastroenterol. 2011;45(8):684-690.
  5. Khayyam U, Sachdeva P, Gomez J, et al. Neurogastroenterol Motil. 2010;22(5): 539-545.
  6. Bonapace ES, Maurer AH, Davidoff S, et al. Am J Gastroenterol. 2000;95(10): 2838-2847.
  7. Bharucha AE, Camilleri M, Veil E, et al. Neurogastroenterol Motil. 2013;25(1):e60-e69.
  8. Lee JS, Camilleri M, Zinsmeister AR, et al. Am J Gastroenterol. 2000;95(10):2751-2761.
  9. Cline MS, Funk C, Kravochuck S, et al. Gastroenterology. 2016;150(4 suppl 1):S729.