CAM 20181

Ingestible pH and Pressure Capsule

Category:Medicine   Last Reviewed:February 2019
Department(s):Medical Affairs   Next Review:February 2020
Original Date:February 2011    

Description:
An ingestible pH and pressure-sensing capsule (SmartPill GI Monitoring System) measures pH, pressure and temperature changes to signify passage of the capsule through portions of the gastrointestinal tract. It is proposed as a means of evaluating gastric emptying for diagnosis of gastroparesis, and colonic transit times for the diagnosis of slow-transit constipation.

For individuals who have suspected disorders of gastric emptying or suspected slow-transit constipation who receive ingestible pH and pressure capsule, the evidence includes studies of test characteristics and case series of patients who have undergone the test. Relevant outcomes are test accuracy and validity, other performance measures, symptoms, functional outcomes and health status measures. The available studies have provided some comparative data on the comparison of the SmartPill ingestible pH plus pressure-sensing capsule and other techniques for measuring gastric emptying and colonic transit times. This evidence primarily consists of concordance with available tests. Because the available tests (e.g., gastric emptying scintigraphy) are imperfect criterion standards, it is not possible to determine the true sensitivity and specificity of SmartPill. The results of the concordance studies have revealed a moderate correlation with alternative tests, but have provided only limited further data on the true accuracy of the test in clinical care. Evaluation of cases with discordant results would be of particular value and, ideally, these studies should be linked to therapeutic decisions and to meaningful clinical outcomes.

Background 
Gastroparesis is a chronic disorder characterized by delayed gastric emptying in the absence of mechanical obstruction. Symptoms of gastroparesis are often nonspecific and may mimic other gastrointestinal tract disorders. It can be caused by many conditions; most commonly it is idiopathic, diabetic or postsurgical.

Constipation is a chronic disorder involving infrequent bowel movements, a sensation of obstruction and incomplete evacuation. Many medical conditions can cause constipation, such as mechanical obstruction, metabolic conditions, myopathies and neuropathies. Diagnostic testing for constipation can aid in distinguishing between 2 categories of disorders, slow-transit constipation and pelvic floor dysfunction.

Gastric emptying scintigraphy is considered the reference standard for diagnosing gastroparesis. The patient ingests a radionuclide-labeled standard meal and subsequent imaging is performed at 0, 1, 2 and 4 hours postprandially, to measure how much of the meal has passed beyond the stomach. A typical threshold to indicate abnormal gastric emptying is more than 10% of the meal remaining at 4 hours after ingestion.

Standard tests used in the evaluation of constipation include ingestion of radiopaque markers and colonic transit scintigraphy. In the radiopaque markers test, small markers are ingested over 1 or several days, and abdominal radiographs are performed at 4 and/or 7 days. The number of remaining markers correlates with the colonic transit time. In colonic transit scintigraphy, a radio-labeled meal is ingested, followed by scintigraphic imaging at several time intervals. The location of the scintigraphic signals correlates with colonic transit times.

Regulatory Status
In 2006, an ingestible capsule (SmartPill® GI Monitoring System; Given Imaging) was cleared for marketing by the U.S. Food and Drug Administration through the 510(k) process, for evaluation of delayed gastric emptying. Gastric emptying is signaled when the pH monitor in the capsule indicates a change in pH from the acidic environment of the stomach to the alkaline environment of the small intestine. For example, an increase of 2 or more pH units usually indicates gastric emptying, and a subsequent decrease of 1 or more pH units usually indicates a passage to the ileocecal junction. While SmartPill® does not measure 50% emptying time, it can be correlated with scintigraphically measured 50% emptying time. The capsule also measures pressure and temperature during its transit through the entire gastrointestinal tract, allowing calculations of total gastrointestinal tract transit time. In 2009, the Food and Drug Administration expanded the use of the SmartPill® to determine colonic transit time for the evaluation of chronic constipation and to differentiate between slow- and normal- transit constipation. When colonic transit time cannot be determined, small and large bowel transit times combined can be used instead. The SmartPill® is not for use in pediatric patients.

Related Policies
20120 Esophageal pH Monitoring
60133 Wireless Capsule Endoscopy as a Diagnostic Technique in Disorders of the Small Bowel, Esophagus and Colon

Policy
Measurement of gastrointestinal transit times, including gastric emptying and colonic transit times, using an ingestible pH and pressure capsule is considered MEDICALLY NECESSARY for the evaluation of suspected gastroparesis, constipation, or other gastrointestinal motility disorders as an alternative to other techniques to evaluate these conditions.

Policy Guidelines
There is a CPT category I code specific to this procedure: 

91112: Gastrointestinal transit and pressure measurement, stomach through colon, wireless capsule, with interpretation and report 

Benefit Application
Blue Card®/National Account Issues
State or federal mandates (e.g., FEP) may dictate that all FDA-approved devices, drugs or biologics may not be considered investigational and, thus, these devices may be assessed only on the basis of their medical necessity.

Rationale
Assessment of diagnostic technology typically focuses on 3 categories of evidence: (1) technical reliability (test-retest reliability or interrater reliability); (2) clinical validity (sensitivity, specificity, positive and negative predictive values) in relevant populations of patients; and (3) clinical utility (i.e., demonstration that the diagnostic information can be used to improve patient outcomes). Additionally, when considering invasive monitoring, any improvements in patient outcomes must be outweighed by device-related risks associated with testing. The following is a summary of the key literature to date.

WIRELESS PH AND PRESSURE CAPSULES
Technical Reliability
We did not identify any literature assessing the technical reliability of wireless pH pressure capsules.

Clinical Validity
Gastric Emptying
Although scintigraphy is considered the reference standard for evaluating gastric emptying, several issues complicate its use as a reference test. Until recently, there has been a lack of test standardization.1 Significant day-to-day variability in the rate of gastric emptying has also been noted.2

Due to a lack of standardization and small sample sizes referenced in published studies, the capability of the gastric emptying test to discriminate between healthy individuals and those with known gastroparesis is uncertain. In a 2000 study by Tougas et al, 123 healthy subjects were assessed to determine the normal period required for nearly complete evacuation of a standardized meal from the stomach.3 The authors suggested that the threshold of normality for gastric retention at 4 hours is 10% meal retention. The cutoff point was set to include 95% of normal persons. However, it appears to be unknown if this same threshold adequately identifies persons who would otherwise be classified as having gastroparesis and who are candidates or responders to treatment.

A few published studies have evaluated the ingestible capsule in relation to another diagnostic measure of gastric emptying. A 2013 systematic review of 12 studies on the ingestible capsule was published by the Agency for Healthcare Research and Quality (AHRQ).4 Studies that included only healthy participants were excluded from the review; instead, AHRQ looked for studies with comparison groups consisting of healthy, asymptomatic (i.e., without symptoms of gastroparesis or constipation) participants as controls, thus limiting interpretation of the comparisons. Among these studies, the overall strength of evidence favoring the ingestible capsule was low. Diagnostic accuracy with the ingestible capsule was considered comparable to gastric scintigraphy in 7 studies, with diagnostic agreement ranging from 58% to 86% for test agreement when results were positive and 64% to 81% when results were negative. There was a moderate correlation between the ingestible capsule and gastric emptying scintigraphy on transit data and device agreement in 5 studies. Three studies that evaluated transit time reported similar sensitivity and specificity rates for the ingestible capsule and scintigraphy.

In 2008, Cassilly et al evaluated the SmartPill and simultaneous gastric emptying scintigraphy in 15 healthy subjects.5 The capsule was ingested immediately following the radiolabeled test meal. In this study, the mean time for 50% gastric emptying by scintigraphy was 95 minutes, 90% gastric emptying by scintigraphy was 194 minutes, and gastric residence time by SmartPill was 261 minutes. The correlation coefficient (r) between SmartPill and 50% gastric emptying time was 0.606, and between SmartPill and 90% gastric emptying time it was 0.565. The average amount of meal remaining in the stomach at the time the SmartPill exited the stomach was 5.4%. This study showed an only modest correlation between the SmartPill and gastric emptying scintigraphy and was too small to establish reference values for the SmartPill.

In a 2008 study by Kuo et al, 87 healthy subjects and 61 subjects with symptoms and prior positive test results for gastroparesis were evaluated with both the SmartPill and gastric emptying scintigraphy.6 In this study, subjects ingested the capsule just before consuming the standard meal. This led to the premature passage of the SmartPill in 5 subjects (<30 minutes) whose tests were subsequently considered invalid. Sixteen other subjects had equipment malfunctions, and two others dropped out.

Among the remaining 125 subjects, the correlation coefficient (r) between SmartPill gastric emptying time and scintigraphy at 2 hours was 0.63, and between SmartPill gastric emptying time and scintigraphy at 4 hours was 0.73. Regarding the capability to discriminate between gastroparetic patients and healthy subjects, the area under the curve was 0.83 for SmartPill, 0.82 for scintigraphy at 4 hours, and 0.79 for scintigraphy at 2 hours (all p>0.05), indicating the similar capability of each for discriminating between the 2 patient groups. At a cutoff point of 300 minutes for the SmartPill, which was established by calculating the ideal cutoff point from the data, the sensitivity was 65%, and specificity was 87%. The sensitivity and specificity for scintigraphy, using an established cutoff point from the literature of 10% at 4 hours, was 44% and 93%, respectively.

Regarding adverse events reported by Kuo et al, 5 (7%) of 67 subjects who did not retrieve the capsule required a second additional plain radiograph beyond 5 days to demonstrate that the capsule had been passed.6 Another patient ingested a laxative that caused the capsule to be entrapped in a viscous mass. An unsuccessful endoscopy ensued, followed by treatment with intravenous erythromycin to pass the capsule from the stomach.

A 2009 study by Maqbool et al assessed SmartPill and gastric emptying scintigraphy in 10 healthy asymptomatic subjects7 Emptying time assessed by SmartPill correlated with the percent meal retained at 2 and 4 hours. The correlation coefficient (r) between SmartPill and 2-hour scintigraphy was 0.95. The correlation between SmartPill and 4-hour scintigraphy was 0.73.

A 2013 study by Green et al assessed SmartPill and gastric emptying scintigraphy in 22 pediatric patients with severe upper gastrointestinal (GI) symptoms.8 Of 20 evaluable patients who had both tests, 9 patients had delayed gastric emptying identified by scintigraphy. SmartPill was 100% sensitive and 50% specific for delayed gastric emptying. Patients also underwent antroduodenal manometry to detect motor abnormalities. SmartPill identified motor abnormalities in 17 patients compared with 10 detected by antroduodenal manometry. However, there does not appear to be a reference standard for motor abnormalities. Thus it cannot be determined whether SmartPill is more sensitive or whether it has a higher false-positive rate for detection of motor abnormalities.

Section Summary: Clinical Validity for Gastric Emptying
The data present several shortcomings on the use of the SmartPill in diagnosing gastroparesis; as a result, the diagnostic accuracy is not well defined. The current reference test (gastric emptying scintigraphy) is an imperfect criterion standard, and this creates difficulties in defining the sensitivity and specificity of SmartPill. All studies cited here included healthy asymptomatic subjects either entirely or as part of a control group. Healthy subjects are not a fair representation of the clinically relevant group under consideration for a diagnosis of delayed gastric emptying. Ideally, the relevant population of subjects should be symptomatic or under evaluation for a diagnosis of gastroparesis. Although there was a moderate correlation between SmartPill gastric emptying time and scintigraphy, scintigraphy itself has limited reliability. Although the areas under the curve between SmartPill and scintigraphy are similar, the modest correlation between the 2 tests indicates that there are often discordant results.

Colonic Transit Time
Few studies have evaluated the use of SmartPill for assessing colonic transit times. In the 2013 systematic review by AHRQ, the strength of evidence in available studies on the ingestible capsule was found to be low overall.4 Accuracy of the ingestible capsule in diagnosing slow-transit constipation was similar to tests using radiopaque markers and scintigraphy. The moderate correlation between colonic transit times with the ingestible capsule and tests with radiopaque markers was shown in 5 studies (r range, 0.69-0.71).  

In the 2009 study by Maqbool et al (discussed earlier), healthy asymptomatic subjects underwent simultaneous whole-gut scintigraphy and SmartPill assessment of whole-gut transit times.7 The 2 techniques correlated with each other reasonably well. In a 2009 study by Rao et al, healthy subjects and subjects with constipation had whole-gut transit times assessed with radiopaque markers and the SmartPill.9 Diagnostic accuracy of the 2 techniques in differentiating between the 2 groups of patients were similar. Camilleri et al (2010) compared the wireless motility capsule with radiopaque markers in 158 patients with chronic functional constipation.10 In this multicenter validation study, the authors reported that positive percent agreement between the wireless motility capsule and radiopaque markers was approximately 80% for colonic transit time (95% confidence interval, 67% to 98%). No serious adverse events were reported.

The U.S. Food and Drug Administration has received 1 adverse event report (according to their MAUDE [Manufacturer and User Facility Device Experience] database), in which the capsule was trapped in the stomach of a patient and required endoscopic removal.

Clinical Utility
Gastric Emptying and Colonic Transit Times
The clinical utility of the test depends on the frequency, duration, and interpretation of imaging and is affected by factors including the use of different test meals and patient positioning. Demonstration of clinical utility further requires that technology is associated with change(s) in management that lead to improved health outcomes.

The 2013 AHRQ review found that there was a lack of evidence on the clinical utility of testing with the ingestible capsule.4 Therefore, the evidence was insufficient to conclude the impact of testing results of the ingestible capsule on treatment and management decisions.

In a 2011 retrospective study by Kuo et al, 83 patients were evaluated for gastroparesis, small intestinal dysmotility, and slow-transit constipation; the authors found that wireless motility capsule testing resulted in a new diagnosis in 44 (53%) patients.11 Changes to clinical management were recommended for 65 patients and included adjustments in medication regimens in 39 (60%) patients and in nutrition programs in 9 (14%) patients. Four (6%) patients were referred to surgery for colectomy. Abnormal gastric emptying or small intestinal transit times each did not influence patient management (p=NS). Abnormal colonic transit times did not influence nutritional program changes (p=0.72) but did influence medication changes (p=0.02) and resulted in a trend toward increased surgical referrals (p=0.12). The authors suggested that wireless motility capsule testing eliminated the need for nuclear gastric emptying testing in 9 (17%) of 52 patients, barium radiography testing in 7 (54%) of 13 patients, and radiopaque marker testing in 41 (68%) of 60 patients. They also noted a need for prospective studies to further understand wireless motility capsule testing and its role in patient management.

In a 2011 retrospective study of 86 patients with persistent symptoms of GI dysmotility despite normal endoscopic and radiologic test results, Rao et al found that evaluations using wireless motility capsule testing resulted in new diagnostic information in 26 (53%) of 50 patients with lower GI symptoms and in 17 (47%) of 36 patients with upper GI symptoms.12 Clinical management was influenced by wireless motility capsule testing in 30% of patients with lower gastrointestinal symptoms and in 50% of patients with upper GI symptoms. The retrospective nature of this study limits interpretation of results.

In a 2015 retrospective review of patients who underwent evaluation with SmartPill for suspected multiregional GI dysmotility, Arora et al reported abnormal test results in 109 (67.7%) of 161 of subjects.13 Of these patients, multiregional dysmotility was diagnosed in 54 (49.5%). Although this study demonstrated a high diagnostic yield among patients with a particular suspected condition, it did not demonstrate improved patient outcomes compared with standard tests.  

SUMMARY OF EVIDENCE
For individuals who have suspected disorders of gastric emptying or suspected slow-transit constipation who receive diagnostic testing with an ingestible pH and pressure capsule, the evidence includes studies of test characteristics and case series of patients who have undergone the test. Relevant outcomes are test accuracy and validity, other performance measures, symptoms, functional outcomes, and health status measures. The available studies have provided some comparative data on the SmartPill ingestible pH plus pressure-sensing capsule and other techniques for measuring gastric emptying and colonic transit times. This evidence primarily consists of assessments of concordance with available tests. Because the available tests (e.g., gastric emptying scintigraphy) are imperfect criterion standards, it is not possible to determine the true sensitivity and specificity of SmartPill. The results of the concordance studies have revealed a moderate correlation with alternative tests, but have provided only limited additional data on the true accuracy of the test in clinical care. Evaluation of cases with discordant results would be of particular value and, ideally, these studies should be linked to therapeutic decisions and to meaningful clinical outcomes..

PRACTICE GUIDELINES AND POSITION STATEMENTS
American Neurogastroenterology and Motility Society
The American Neurogastroenterology and Motility Society issued a consensus statement on intraluminal measurement of gastrointestinal and colonic motility in clinical practice in 2008.14 In this consensus statement, formal recommendations on any type of test were not issued. It was noted that SmartPill could be used to identify delayed gastric emptying, but that the impact of the technology on patient management has not been studied. Use of SmartPill to assess colonic motility was noted, but no mention was made of its use to measure colonic transit time.

American and European Neurogastroenterology and Motility Societies
The American and European Neurogastroenterology and Motility Societies issued a position paper on the evaluation gastrointestinal transit in 2011.15 In it, the wireless motility capsule was recommended by consensus for assessing gastric emptying and small bowel, colonic, and whole-gut transit times in patients with suspected gastroparesis or gastrointestinal dysmotility in multiple regions. However, the position paper noted that the clinical utility of identifying delays in small bowel transit times is unknown.

American Gastroenterological Association
The American Gastroenterological Association’s 2013 guidelines on gastroparesis diagnosis and treatment indicated wireless motility capsule testing requires validation before it can be considered as an alternative to scintigraphy for diagnosing gastroparesis.16 Gastric emptying scintigraphy was considered the best-accepted method to test for delays in gastric emptying.

U.S. PREVENTIVE SERVICES TASK FORCE RECOMMENDATIONS
Not applicable. 

ONGOING AND UNPUBLISHED CLINICAL TRIALS
Some currently unpublished trials that might influence this review are listed in Table 1.

Table 1. Summary of Key Trials

NCT No. Trial Name Planned Enrollment Completion Date

Unpublished

NCT02022826a

Clinical Management With SmartPill Motility Monitoring System and Validation of the SmartPill Five Hour Cutoff in Patients With Symptoms of Gastroparesis

167 Dec 2016 (terminated)

NCT: national clinical trial.
ª Denotes industry-sponsored or cosponsored trial. 

References: 

  1. Abell TL, Camilleri M, Donohoe K, et al. Consensus recommendations for gastric emptying scintigraphy: a joint report of the American Neurogastroenterology and Motility Society and the Society of Nuclear Medicine. J Nucl Med Technol. Mar 2008;36(1):44-54. PMID 18287197
  2. Parkman HP, Hasler WL, Fisher RS. American Gastroenterological Association technical review on the diagnosis and treatment of gastroparesis. Gastroenterology. Nov 2004;127(5):1592-1622. PMID 15521026
  3. Tougas G, Eaker EY, Abell TL, et al. Assessment of gastric emptying using a low fat meal: establishment of international control values. Am J Gastroenterol. Jun 2000;95(6):1456-1462. PMID 10894578
  4. Stein E, Berger Z, Hutfless S, et al. Wireless Motility Capsule Versus Other Diagnostic Technologies for Evaluating Gastroparesis and Constipation: A Comparative Effectiveness Review. Rockville, MD: Agency for Healthcare Research and Quality; 2013.
  5. Cassilly D, Kantor S, Knight LC, et al. Gastric emptying of a non-digestible solid: assessment with simultaneous SmartPill pH and pressure capsule, antroduodenal manometry, gastric emptying scintigraphy. Neurogastroenterol Motil. Apr 2008;20(4):311-319. PMID 18194154
  6. Kuo B, McCallum RW, Koch KL, et al. Comparison of gastric emptying of a nondigestible capsule to a radio-labelled meal in healthy and gastroparetic subjects. Aliment Pharmacol Ther. Jan 15 2008;27(2):186-196. PMID 17973643
  7. Maqbool S, Parkman HP, Friedenberg FK. Wireless capsule motility: comparison of the SmartPill GI monitoring system with scintigraphy for measuring whole gut transit. Dig Dis Sci. Oct 2009;54(10):2167-2174. PMID 19655250
  8. Green AD, Belkind-Gerson J, Surjanhata BC, et al. Wireless motility capsule test in children with upper gastrointestinal symptoms. J Pediatr. Jun 2013;162(6):1181-1187. PMID 23290514
  9. Rao SS, Kuo B, McCallum RW, et al. Investigation of colonic and whole-gut transit with wireless motility capsule and radiopaque markers in constipation. Clin Gastroenterol Hepatol. May 2009;7(5):537-544. PMID 19418602
  10. Camilleri M, Thorne NK, Ringel Y, et al. Wireless pH-motility capsule for colonic transit: prospective comparison with radiopaque markers in chronic constipation. Neurogastroenterol Motil. Aug 2010;22(8):874-882, e233. PMID 20465593
  11. Kuo B, Maneerattanaporn M, Lee AA, et al. Generalized transit delay on wireless motility capsule testing in patients with clinical suspicion of gastroparesis, small intestinal dysmotility, or slow transit constipation. Dig Dis Sci. Oct 2011;56(10):2928-2938. PMID 21625964
  12. Rao SS, Mysore K, Attaluri A, et al. Diagnostic utility of wireless motility capsule in gastrointestinal dysmotility. J Clin Gastroenterol. Sep 2011;45(8):684-690. PMID 21135705
  13. Arora Z, Parungao JM, Lopez R, et al. Clinical utility of wireless motility capsule in patients with suspected multiregional gastrointestinal dysmotility. Dig Dis Sci. May 2015;60(5):1350-1357. PMID 25399332  
  14. Camilleri M, Bharucha AE, di Lorenzo C, et al. American Neurogastroenterology and Motility Society consensus statement on intraluminal measurement of gastrointestinal and colonic motility in clinical practice. Neurogastroenterol Motil. Dec 2008;20(12):1269-1282. PMID 19019032
  15. Rao SS, Camilleri M, Hasler WL, et al. Evaluation of gastrointestinal transit in clinical practice: position paper of the American and European Neurogastroenterology and Motility Societies. Neurogastroenterol Motil. Jan 2011;23(1):8-23. PMID 21138500
  16. Camilleri M, Parkman HP, Shafi MA, et al. Clinical guideline: management of gastroparesis. Am J Gastroenterol. Jan 2013;108(1):18-37; quiz 38. PMID 23147521

Coding Section

Codes Number Description
CPT 91112 Gastrointestinal transit and pressure measurement, stomach through colon, wireless capsule, with interpretation and report (new code 01/01/13)
ICD-9-CM Diagnosis   Investigational for all relevant diagnoses
ICD-10-CM (effective 10/01/15)   Investigational for all relevant diagnoses
  E08.43 Diabetes mellitus due to underlying condition with diabetic autonomic (poly)neuropathy
  E09.43 Drug or chemical induced diabetes mellitus with neurological complications with diabetic autonomic (poly)neuropathy
  E10.43 Type 1 diabetes mellitus with diabetic autonomic (poly)neuropathy
  E11.43 Type 2 diabetes mellitus with diabetic autonomic (poly)neuropathy
  E13.43 Other specified diabetes mellitus with diabetic autonomic (poly)neuropathy
  K59.00-K59.09 Constipation code range
ICD-10-PCS (effective 10/01/15)  

 ICD-10-PCS codes are only used for inpatient services. There is no specific ICD-10-PCS code for this procedure.

Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each policy. They may not be all-inclusive.

This medical policy was developed through consideration of peer-reviewed medical literature generally recognized by the relevant medical community, U.S. FDA approval status, nationally accepted standards of medical practice and accepted standards of medical practice in this community, Blue Cross and Blue Shield Association technology assessment program (TEC) and other non-affiliated technology evaluation centers, reference to federal regulations, other plan medical policies and accredited national guidelines.

"Current Procedural Terminology© American Medical Association.  All Rights Reserved" 

History From 2014 Forward     

02/01/2019 

Annual review, no change to policy intent. 

05/02/2018 

Interim review to update policy statement from being investigational to the following: Measurement of gastrointestinal transit times, including gastric emptying and colonic transit times, using an ingestible pH and pressure capsule is considered MEDICALLY NECESSARY for the evaluation of suspected gastroparesis, constipation, or other gastrointestinal motility disorders as an alternative to other techniques to evaluate these conditions

02/28/2018 

Annual review, no change to policy status. Adding regulatory status and updating rationale. No other changes made. 

02/01/2017 

Annual review, no change to policy intent. Updating background, description, rationale and references. 

02/17/2016 

Annual review, no change to policy intent. Updating background, description, guidelines, rationale and references. 

02/18/2015 

Annual review, no change to policy intent. Updated rationale and references. Added guidelines and coding.

02/6/2014

Annual Review. Updated rationale, references and description. Added related policies. No change to policy intent.


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