Technique of functional and motility test: how to perform antroduodenal manometry

The origin of intraluminal pressure waves in gastrointestinal tract

The gastrointestinal (GI) peristalsis is an involuntary wave-like contraction of the GI wall that helps to propagate food along the tract. Many GI diseases, e.g., gastroparesis, are known to cause motility disorders in which the physiological contractile patterns of the wall get disrupted. Therefore, to understand the pathophysiology of these diseases, it is necessary to understand the mechanism of GI motility. We present a coupled electromechanical model to describe the mechanism of GI motility and the transduction pathway of cellular electrical activities into mechanical deformation and the generation of intraluminal pressure (IP) waves in the GI tract. The proposed model consolidates a smooth muscle cell (SMC) model, an actin-myosin interaction model, a hyperelastic constitutive model, and a Windkessel model to construct a coupled model that can describe the origin of peristaltic contractions in the intestine. The key input to the model is external electrical stimuli, which are converted into mechanical contractile waves in the wall. The model recreated experimental observations efficiently and was able to establish a relationship between change in luminal volume and pressure with the compliance of the GI wall and the peripheral resistance to bolus flow. The proposed model will help us understand the GI tract's function in physiological and pathophysiological conditions.

Physiological characterization of gastric emptying using high-resolution antropyloroduodenal manometry

Delayed gastric emptying (GE) has been associated with antral and pyloric dysmotility. We aimed to characterize differences in the antral, duodenal, and pyloric motility profiles associated with delayed GE, using high-resolution antropyloroduodenal manometry (HR-ADM). Patients referred for HR-ADM for dyspeptic symptoms performed a concurrent GE breath test (NCT01519180 and NCT04918329). HR-ADM involved 36 sensors 1 cm apart, placed across the pylorus. Interdigestive and postprandial periods were identified. Antral, pyloric, and duodenal motor profiles were analyzed recording the frequency, amplitude, and propagative nature of contractions for each period. Plots of patients with normal and delayed GE were compared. Sixty patients underwent both HR-ADM and GE tests. Twenty-five and 35 patients had delayed and normal GE, respectively. Antral and duodenal motor profiles were not different between the two groups during the interdigestive period. During the postprandial period, a lower frequency of antral contractions was associated with delayed GE (2.22 vs. 1.39 contractions/min; P = 0.002), but no difference in mean contraction amplitude was observed. The pyloric region was identified in all the patients and pylorospasms, defined as 3 min of repeated isolated pyloric contractions, were more frequent in patients with delayed GE (32.0% vs. 5.7%; P = 0.02) during the postprandial period. No difference in duodenal contraction profiles was observed. Manometric profile alterations were observed in 72% of the patients with delayed GE, with 56% having a low frequency of antral contractions. Using HR-ADM, patients with delayed GE displayed different postprandial antropyloric motility as compared with patients with normal GE.NEW & NOTEWORTHY High-resolution antropyloroduodenal manometry (HR-ADM) allows precise characterization of antral, pyloric, and duodenal motility, although its association with gastric emptying (GE) has been poorly investigated. Concurrent HR-ADM with GE measurement showed a lower frequency of antral postprandial contractions and an increased frequency of postprandial pylorospasms in patients with delayed GE. HR-ADM could, therefore, be useful in the future to better select patients for treatments targeting the pylorus.

The Overlap Subgroup of Functional Dyspepsia Exhibits More Severely Impaired Gastric and Autonomic Functions

GOALS

A combination of multiple tests was introduced to noninvasively investigate the differences in pathophysiologies among functional dyspepsia (FD) subgroups, including postprandial distress syndrome (PDS), epigastric pain syndrome (EPS), and overlap.

BACKGROUND

It has not been extensively evaluated whether different pathophysiologies are involved in FD subgroups.

STUDY

This multicenter study included 364 FD patients fulfilling Rome IV criteria and 47 healthy controls. A combined noninvasive gastric and autonomic function test was performed: The electrogastrogram and electrocardiogram were recorded simultaneously in the fasting state and after a drink test. Symptoms after drinking were recorded using visual analog scale.

RESULTS

(1) Compared with HC, FD patients showed a decreased maximum tolerable volume (MTV) ( P <0.01) and percentage of normal gastric slow waves [normal gastric slow waves (%NSW)] ( P <0.01), and increased postdrinking symptoms, anxiety ( P <0.01), and depression ( P <0.01). The drink reduced %NSW in both FD patients and HC; however, the effect was more potent in patients. (2) The PDS and overlap groups displayed a reduced MTV ( P <0.05). The overlap group exhibited a higher symptom score at 30 minutes after drinking, and higher anxiety and depression scores, and a higher sympathovagal ratio than the EPS ( P <0.05 for all) and PDS ( P <0.01 for all). (3) In the PDS subgroup, the MTV, postprandial sympathovagal ratio, and depression were associated with the overall dyspepsia symptom scale (DSS, P =0.034, 0.021, 0.043, respectively). No significant associations were found in the other 2 subgroups.

CONCLUSIONS

The combination of multiple tests can detect pathophysiological abnormities in FD patients. Overall, patients with overlap symptoms display more severe pathophysiologies.

Diagnostic Methods for Evaluation of Gastric Motility-A Mini Review

Gastric motility abnormalities are common in patients with disorders of gut-brain interaction, such as functional dyspepsia and gastroparesis. Accurate assessment of the gastric motility in these common disorders can help understand the underlying pathophysiology and guide effective treatment. A variety of clinically applicable diagnostic methods have been developed to objectively evaluate the presence of gastric dysmotility, including tests of gastric accommodation, antroduodenal motility, gastric emptying, and gastric myoelectrical activity. The aim of this mini review is to summarize the advances in clinically available diagnostic methods for evaluation of gastric motility and describe the advantages and disadvantages of each test.

A novel scalable electrode array and system for non-invasively assessing gastric function using flexible electronics

BACKGROUND

Disorders of gastric function are highly prevalent, but diagnosis often remains symptom-based and inconclusive. Body surface gastric mapping is an emerging diagnostic solution, but current approaches lack scalability and are cumbersome and clinically impractical. We present a novel scalable system for non-invasively mapping gastric electrophysiology in high-resolution (HR) at the body surface.

METHODS

The system comprises a custom-designed stretchable high-resolution "peel-and-stick" sensor array (8 × 8 pre-gelled Ag/AgCl electrodes at 2 cm spacing; area 225 cm² ), wearable data logger with custom electronics incorporating bioamplifier chips, accelerometer and Bluetooth synchronized in real-time to an App with cloud connectivity. Automated algorithms filter and extract HR biomarkers including propagation (phase) mapping. The system was tested in a cohort of 24 healthy subjects to define reliability and characterize features of normal gastric activity (30 m fasting, standardized meal, and 4 h postprandial).

KEY RESULTS

Gastric mapping was successfully achieved non-invasively in all cases (16 male; 8 female; aged 20-73 years; BMI 24.2 ± 3.5). In all subjects, gastric electrophysiology and meal responses were successfully captured and quantified non-invasively (mean frequency 2.9 ± 0.3 cycles per minute; peak amplitude at mean 60 m postprandially with return to baseline in <4 h). Spatiotemporal mapping showed regular and consistent wave activity of mean direction 182.7° ± 73 (74.7% antegrade, 7.8% retrograde, 17.5% indeterminate).

CONCLUSIONS AND INFERENCES

BSGM is a new diagnostic tool for assessing gastric function that is scalable and ready for clinical applications, offering several biomarkers that are improved or new to gastroenterology practice.

Is staple line reinforcement still needed on contemporary staplers? A benchtop analysis

BACKGROUND

Staple line reinforcement (SLR) is commonly used in bariatric surgeries to reduce leaks and bleeds. With the evolution of staplers, the need for buttressing with the latest surgical stapling technology is in question. The efficacy of GORE® SEAMGUARD® (G-SLR) to improve staple line strength based on an established measure of burst pressure was evaluated. A benchtop test on synthetic tissue evaluated the pressure required for staple line leak across surgical staplers with and without G-SLR.

METHODS

Staple lines on a consistent thickness synthetic bowel were pressurized to the point of failure (burst pressure) among Ethicon®, Intuitive®, and Medtronic® surgical staplers with and without G-SLR. Burst pressure and leak location (through the staple line [TTSL] or through the staple [TTS], on the anvil or cartridge side) were recorded. Visual confirmation of a leak concluded each test.

RESULTS

The pooled mean burst pressure for G-SLR was greater (p < 0.05) by 0.494 pounds/square inch compared with no reinforcement with no meaningful differences among staplers. Leak failures were primarily TTS (91.7%) and equally distributed between reinforcement groups with more leak failures on the cartridge side with G-SLR and on the anvil side for non-SLR group. Leaks occurred across the length of staple lines with no discernable pattern.

CONCLUSION

Employing a buttressing material strengthens the staple line, as measured by burst pressure, and may reduce the risk for staple line failure. This benchtop study of G-SLR with three commonly used surgical staplers demonstrated a significant increase in burst pressures among the studied stapling devices.

Intra- and Inter-observer Agreement of High Resolution Antroduodenal Manometry in Pediatric Patients Among Single Center Experts

OBJECTIVES

Studies in adults have suggested that high-resolution technology increases the diagnostic yield of antroduodenal manometry (ADM). However, there is no study comparing high-resolution with low-resolution ADM recordings as well as comparing the 2 types of high-resolution display [conventional line plot (CLP) and pressure topographic plots (PTP)]. We hypothesized that high-resolution ADM is a superior diagnostic modality with higher inter-observer and intra-observer agreement compared with low-resolution recordings.

METHODS

Twenty-four anonymized ADM studies were blindly analyzed by 3 experienced pediatric neurogastroenterologists. All studies had been performed using a low-compliance water-perfused system with a 20-channels catheter. Data were displayed as CLP, as both high-resolution and low-resolution, and PTP in different sessions with at least 6-week interval. Accuracy was evaluated using previous established diagnosis and specific pre-prandial and post-prandial manometric patterns. Inter-observer and intra-observer agreements were calculated.

RESULTS

Analysis with high-resolution CLP revealed a substantial inter-observer agreement among the 3 observers regarding the diagnosis (Krippendorff's alpha: 0.832; average pairwise percentage agreement: 88.9%). Conversely, PTP and low-resolution CLP showed poor agreement for diagnoses (Krippendorff's alpha: 0.600; average pairwise percentage agreement: 75.3%; Krippendorff's alpha: 0.390; average pairwise percentage agreement: 60.2%, respectively). For the intra-observer agreement, Krippendorff's alpha ranges were 0.891-1 for CLP and 0.19393-0.34621 for PTP.

CONCLUSIONS

Our study demonstrated higher diagnostic accuracy for high-resolution ADM compared to the low-resolution recordings. However, although it is well established for other motility investigations, PTP is not yet reliable in assessing foregut motor patterns. Advanced and more sophisticated software are clearly required for analyzing PTP display.

Antroduodenal motility recording identifies characteristic patterns in gastroparesis related to underlying etiology

BACKGROUND

Gastroparesis (GP) is a gastrointestinal disorder associated with significant morbidity and healthcare costs. GP patients form a heterogeneous population with diverse etiology, and treatment is often challenging due to a poorly understood underlying pathophysiology. The aim of the present study was to assess antroduodenal motility patterns among the different GP etiologies.

METHODS

We reviewed antroduodenal manometry (ADM) recordings of patients with confirmed GP between 2009 and 2019. ADM measurements were evaluated for fed period duration, number of phase III contractions and migrating motor complexes (MMCs), motility index (MI), and presence of neuropathic patterns.

KEY RESULTS

A total of 167 GP patients (142 women, median age 45 [31-57]) were included. The following etiologies were identified: idiopathic n = 101; post-surgery n = 36; and diabetes n = 30. Fed period duration was significantly longer in idiopathic (p &lt; 0.01) and diabetic GP patients (p &lt; 0.05) compared with post-surgery GP patients. Furthermore, the number and duration of phase III contractions and the number of MMCs were significantly lower in idiopathic and diabetic patients compared with post-surgery GP patients (p &lt; 0.01). Likewise, absence of MMCs during 6-h recording was more often observed in idiopathic and diabetes GP patients compared with post-surgery GP patients (resp. p &lt; 0.01 and p &lt; 0.05).

CONCLUSIONS AND INFERENCES

Antroduodenal motility patterns are different among GP etiologies. A dysmotility spectrum was identified with different patterns ranging from post-surgery GP to idiopathic and diabetic GP.

Gastrointestinal and Liver Complications in Patients with Diabetes Mellitus-A Review of the Literature

The number of diabetes mellitus patients has increased over the last few years in developing countries, along with obesity and sedentary lifestyle. Besides macroangiopathy and microangiopathy, damage to the nerve fibers of the peripheral nervous system is the most common chronic complication of diabetes. Digestive complications in diabetic patients represent a consequence of diabetic autonomic neuropathy involving the gastrointestinal tract, but unfortunately not always evaluated by diabetologists. Aside from the complications encountered in the digestive tract, patients with diabetes mellitus are prone to developing liver diseases. This review will describe the prevalence of these complications, the modality of diagnosis, and therapeutical solutions in order to reduce the risk of progression of these complications in diabetic subjects.

Short Bowel Syndrome and Dysmotility

Due to recent advances, the mortality due to short bowel syndrome (SBS) has significantly decreased, but the morbidities are still high. Morbidities arising specifically due to dysmotility in SBS include feeding intolerance, prolonged dependence on parenteral nutrition, and associated complications such as intestinal failure associated liver disease, and bloodstream infections. The understanding of the pathogenesis of dysmotility in SBS has improved vastly. However, the tools to diagnose dysmotility in SBS in infants are restrictive, and the medical therapies to treat dysmotility are limited. Surgical techniques available for the treatment after failure of conservative management of dysmotility offer hope but carry their associated risks. The evidence to support either the medical therapies or the surgical techniques to treat dysmotility in SBS in children is scarce and weak. Development of newer therapies and efforts to build evidence to support currently available treatments in treating dysmotility in SBS is needed.

Enhancing the utility of antroduodenal manometry in pediatric intestinal pseudo-obstruction

BACKGROUND

Antroduodenal manometry (ADM) and histopathology are currently employed to aid the diagnosis of pediatric intestinal pseudo-obstruction (PIPO). Limited data are available on the reliability of ADM analysis and its correlation with histopathology. We aimed to develop a protocol for enhanced analysis of ADM contractile patterns, including a scoring system, and explore whether this provided better correlation with histopathology.

METHODS

Children referred with suspected PIPO between April 2012-December 2019 who underwent both ADM and full-thickness biopsies were included. ADM tracings were analyzed using both standard (conventional ADM) and novel (enhanced ADM) motility parameters. A novel ADM score (GLASS score) was generated based on the enhanced ADM analysis. Conventional and enhanced ADM analyses were then correlated with histopathology.

RESULTS

Forty patients were included. Using conventional clinical criteria, 29 of these were diagnosed with PIPO and the other 11 with non-PIPO diagnoses. Twenty-three of the PIPO patients had abnormal histopathology: 6 myopathy, 4 neuropathy, 3 neuro-myopathy, and 10 non-specific changes. No agreement in diagnosis was found between conventional ADM analysis and histopathology (ϰ = 0.068; p = 0.197), whereas the latter significantly correlated with enhanced ADM analysis (ϰ = 0.191; p = 0.003). The enhanced ADM score was significantly higher in PIPO versus non-PIPO (16.0 vs. 8.0; p < 0.001).

CONCLUSIONS

As opposed to conventional analysis protocols, the newly developed enhanced ADM analysis and associated score is not only able to discriminate between PIPO and non-PIPO patients, but also between distinct histopathological pathologies. Further studies are required to assess the utility of enhanced ADM analysis in larger populations.

Assessment of whole gut motility in adolescents using the wireless motility capsule test

Functional gastrointestinal (GI) disorders are often associated with intestinal dysmotility representing a diagnostic challenge. A relatively new method is the wireless motility capsule (WMC) test, which continuously measures pH, pressure, temperature and regional transit times as it passes through the GI tract. In adults, the WMC test was approved for use in the diagnosis of gastroparesis and constipation by assessing GI transit and contractility. We performed the WMC test in nine adolescent patients aged 12-17 years with functional GI symptoms from July 2017 until February 2019. Abnormal transit times were detected in four patients. Three patients showed abnormal transit times of the upper GI tract: in two cases, contractility analysis revealed prolonged gastric retention, and in one patient, abnormal colonic transit was detected.Conclusion: The WMC test is a minimally invasive procedure with potential to expand future diagnostic opportunities for paediatric patients with functional GI disorders and suspected motility disturbances. What is Known: • The assessment of GI transit and contractility of the whole gut is possible with the WMC test which is approved for use in the diagnosis of gastroparesis and constipation in adults. What is New: • The WMC test is a non-invasive diagnostic tool with the potential to expand diagnostic opportunities in paediatric patients by assessing regional and whole gut motility. • In paediatric patients with functional GI disorders, the WMC test could help to make an adequate diagnosis and initiate appropriate therapy.

Automatic assessment of human gastric motility and emptying from dynamic 3D magnetic resonance imaging

BACKGROUND

Time-sequenced magnetic resonance imaging (MRI) of the stomach is an emerging technique for non-invasive assessment of gastric emptying and motility. However, an automated and systematic image processing pipeline for analyzing dynamic 3D (ie, 4D) gastric MRI data has not been established. This study uses an MRI protocol for imaging the stomach with high spatiotemporal resolution and provides a pipeline for assessing gastric emptying and motility.

METHODS

Diet contrast-enhanced MRI images were acquired from seventeen healthy humans after they consumed a naturalistic contrast meal. An automated image processing pipeline was developed to correct for respiratory motion, to segment and compartmentalize the lumen-enhanced stomach, to quantify total gastric and compartmental emptying, and to compute and visualize gastric motility on the luminal surface of the stomach.

KEY RESULTS

The gastric segmentation reached an accuracy of 91.10 ± 0.43% with the Type-I error and Type-II error being 0.11 ± 0.01% and 0.22 ± 0.01%, respectively. Gastric volume decreased 34.64 ± 2.8% over 1 h where the emptying followed a linear-exponential pattern. The gastric motility showed peristaltic patterns with a median = 4 wave fronts (range 3-6) and a mean frequency of 3.09 ± 0.07 cycles per minute. Further, the contractile amplitude was stronger in the antrum than in the corpus (antrum vs. corpus: 5.18 ± 0.24 vs. 3.30 ± 0.16 mm; p < 0.001).

CONCLUSIONS & INFERENCES

Our analysis pipeline can process dynamic 3D MRI images and produce personalized profiles of gastric motility and emptying. It will facilitate the application of MRI for monitoring gastric dynamics in research and clinical settings.

Diagnostic Evaluation of Gastric Motor and Sensory Disorders

Disorders of gastric motor and sensory function affect 10%-20% of the world's population and adversely impact nutrition, quality of life, work productivity, and health care costs. Classifying these disorders can be challenging given the heterogeneity of symptom presentation, the presence of symptoms unexplained by endoscopic, radiographic and/or laboratory evaluation, and overlap with other luminal gastrointestinal disorders. Accurately diagnosing these highly prevalent disorders relies upon an understanding of epidemiology and risk factors, the ability to take a careful clinical history focused on symptoms, and the presence of predisposing medical, surgical, and psychological conditions. A variety of diagnostic studies are now available to assess gastric motor function and identify maladaptive relaxation, accommodation, and abnormal sensation. FDA-approved treatment options are limited and thus many patients undergo a series of empirical treatment trials that target individual symptoms, often without much benefit. This article provides updated recommendations for identifying and classifying the most common gastric motor and sensory disorders using currently accepted diagnostic tests, and provides a brief supplemental overview on treatment options. "Things sweet to taste prove in digestion sour." -Shakespeare, Richard II, 1595.

Pilot Validation of a New Wireless Patch System as an Ambulatory, Noninvasive Tool That Measures Gut Myoelectrical Signals: Physiologic and Disease Correlations

BACKGROUND AND AIMS

Limited means exist to assess gastrointestinal activity in a noninvasive, objective way that is highly predictive of underlying motility disorders. The aim of this paper is to demonstrate the feasibility of recording myoelectric gastrointestinal activity by cutaneous patches and to correlate myoelectric signals with gastrointestinal function in various clinical settings.

METHODS

A novel wireless patch system (WPS) (G-Tech Medical) that acquires gastrointestinal myoelectrical signals was placed on the patients' anterior abdomens. Data were transmitted wirelessly to a mobile device with a user interface and forwarded to a cloud server where processing algorithms identified episodes of motor activity, quantified their parameters, and nominally assigned them to specific gastrointestinal organs based on their frequencies.

RESULTS

The inherent reproducibility of the WPS measurement technique itself and from the underlying gut activity, coupled with source validation and sensitivity to changes in gut activity in several physiologic and pathologic states, demonstrates its feasibility, safety, and performance in clinical settings.

CONCLUSIONS

The novel WPS technology, measuring myoelectric intestinal activity noninvasively and continuously over multiple days, is feasible in a wide range of clinical settings, highlighting its promise in the diagnosis and management of motility disorders. Further research is required for more extensive validation and to determine how best to employ this information to optimize patient care.

Effects of Provocative Testing on Phase III Migrating Motor Complex in Children

OBJECTIVES

Antroduodenal manometry (ADM) is used to evaluate antral and small intestinal motility, with the presence of phase III migrating motor complexes (MMCs) indicating an intact enteric neuromuscular system. The lack of evidence-based or consensus-driven established norms for MMC in fasting phase and after provocative testing marks a major limitation in the interpretation of ADM studies. We aimed to determine the characteristics of MMC in fasting and post-provocative phase in children.

METHODS

Data from subjects ages <20 years with ADM results evaluated at neuro-gastroenterology and Motility Disorders Center, Cincinnati Children's Hospital Medical Center from January 2018 to March 2019 were analyzed.

RESULTS

Forty-eight ADM tracings that did not demonstrate abnormal patterns were included; the mean age was 10.00 ± 5.72 years and 50% were male. Indications for ADM included: vomiting (27.1%), feeding intolerance (27.1%), abdominal pain (16.6%), nausea (14.6%), and abdominal distension (14.6%). Thirty-seven percent of subjects had enteral access for feeds. During fasting, one-third of all MMC originated in the antrum. Azithromycin-induced MMC occurred in 28% of subjects and two-thirds of these originated in the antrum with antral contractions of significantly higher frequency and amplitude compared to fasting. Octreotide significantly increased frequency, amplitude, and duration of MMC compared to fasting, with 76% originating in the antrum. Both azithromycin and octreotide induced more than one MMC in a third of subjects.

CONCLUSIONS

We describe the characteristics of antral and small intestinal motility during fasting and after provocative testing in children. These values will help standardize our interpretation of pediatric ADM studies.

Auxiliary Tests of Autonomic Functions

SUMMARY

The autonomic nervous system is a complex neural network that controls several organ systems. Its assessment includes a detailed history of autonomic functions, clinical examination, and autonomic tests. Most widely used is a battery of tests that assess cardiovascular reflex autonomic and sudomotor tests, which include deep breathing (assesses parasympathetic function), Valsalva maneuver, tilt test (both assess parasympathetic and adrenergic functions), and sudomotor testing for the evaluation of postganglionic sudomotor fibers. These basic tests represent a foundation of autonomic testing. Nevertheless, the autonomic nervous system also controls organ systems not directly assessed by basic tests. This review describes a number of auxiliary autonomic tests that can be used in addition to basic autonomic tests or can be used independently to explore particular autonomic functions or to answer a specific clinical question. The auxiliary tests described in this review evaluate cardiovascular, thermoregulatory, gastrointestinal, genitourinary, eye, and exocrine functions. These tests are cold pressor test, sustained handgrip maneuver, reverse tilt test, venoarteriolar reflex, laser Doppler flare imaging, microneurography, neck suction, lower body negative pressure, venous occlusion plethysmography, pharmacologic assessment of postganglionic sympathetic outflow, plasma norepinephrine, sympathetic skin response, video cinefluoroscopic swallowing test, esophageal manometry test, small bowel manometry test, wireless motility capsule test, urodynamic studies, penile plethysmography, intracavernosal papaverine injection, infrared video pupillography, corneal confocal microscopy, pupillary response to dilute pilocarpine and hydroxyamphetamine, Schirmer test, tear osmolarity test, and salivary secretion test. The protocol of each test is described in detail. This review can be used as a quick reference for the auxiliary autonomic tests.

Assessment of Gastrointestinal Autonomic Dysfunction: Present and Future Perspectives

The autonomic nervous system delicately regulates the function of several target organs, including the gastrointestinal tract. Thus, nerve lesions or other nerve pathologies may cause autonomic dysfunction (AD). Some of the most common causes of AD are diabetes mellitus and α-synucleinopathies such as Parkinson’s disease. Widespread dysmotility throughout the gastrointestinal tract is a common finding in AD, but no commercially available method exists for direct verification of enteric dysfunction. Thus, assessing segmental enteric physiological function is recommended to aid diagnostics and guide treatment. Several established assessment methods exist, but disadvantages such as lack of standardization, exposure to radiation, advanced data interpretation, or high cost, limit their utility. Emerging methods, including high-resolution colonic manometry, 3D-transit, advanced imaging methods, analysis of gut biopsies, and microbiota, may all assist in the evaluation of gastroenteropathy related to AD. This review provides an overview of established and emerging assessment methods of physiological function within the gut and assessment methods of autonomic neuropathy outside the gut, especially in regards to clinical performance, strengths, and limitations for each method.

Erythromycin stimulates phasic gastric contractility as assessed with an isovolumetric intragastric balloon pressure measurement

BACKGROUND

A novel technique to assess gastric motility by measuring the pressure in a low-volume intragastric balloon was developed to monitor (disordered) motility. We previously showed that this technique allows measuring pharmacologically induced inhibition of motility. In this study, we assessed whether it is possible to measure pharmacologically induced stimulation of gastric motility using 200 mg erythromycin. Erythromycin is a highly effective stimulator of gastric emptying and contractility.

METHODS

After an overnight fast, a nasogastric balloon catheter was introduced in healthy subjects. After inflation with 120 ml of air, the catheter was connected to a pressure sensor. Intraballoon pressure was continuously recorded for 4 h. After a baseline recording of 2 h, 200 mg erythromycin was infused intravenously over 20 min while the recording continued for 2 h. Epigastric symptoms were surveyed on 100-mm visual analogue scales. Motility was quantified from the pressure recording as a gastric balloon motility index. Wilcoxon signed-rank tests were performed. Data are shown as median (interquartile range).

KEY RESULTS

Six subjects were enrolled and five completed the procedures (age: 28 (25-29) years, body mass index: 24.0 (23.8-24.5) kg m^-2 ). One subject could not tolerate tube placement. Bloating, nausea, and epigastric sensation scores were 0 (0-3), 0 (0-1), and 1 (0-1) mm, respectively. Erythromycin significantly increased the motility index from 0.48 (0.41-0.51) to 0.79 (0.70-0.82) (p = 0.03).

CONCLUSIONS AND INFERENCES

Gastric motility assessed via pressure measurement in a low-volume intragastric balloon is able to detect pharmacologically stimulated motility in healthy subjects, which further validates this technique.

Gastroesophageal Reflux Disease and Foregut Dysmotility in Children with Intestinal Failure

Gastrointestinal dysmotility is a common problem in a subgroup of children with intestinal failure (IF), including short bowel syndrome (SBS) and pediatric intestinal pseudo-obstruction (PIPO). It contributes significantly to the increased morbidity and decreased quality of life in this patient population. Impaired gastrointestinal (GI) motility in IF arises from either loss of GI function due to the primary disorder (e.g., neuropathic or myopathic disorder in the PIPO syndrome) and/or a critical reduction in gut mass. Abnormalities of the anatomy, enteric hormone secretion and neural supply in IF can result in rapid transit, ineffective antegrade peristalsis, delayed gastric emptying or gastroesophageal reflux. Understanding the underlying pathophysiologic mechanism(s) of the enteric dysmotility in IF helps us to plan an appropriate diagnostic workup and apply individually tailored nutritional and pharmacological management, which might ultimately lead to an overall improvement in the quality of life and increase in enteral tolerance. In this review, we have focused on the pathogenesis of GI dysmotility in children with IF, as well as the management and treatment options.

Assessment of Pyloric Sphincter Physiology Using Functional Luminal Imaging Probe in Healthy Volunteers

Background/Aims

The functional luminal imaging probe (FLIP) can measure tissue distensibility and geometric changes through volumetric distention. The esophagogastric junction has been well studied using EndoFLIP, studies on pylorus are lacking. We aim to study biomechanical properties of pylorus using EndoFLIP to create normative data.

Methods

We performed a prospective study of 20 healthy volunteers (ages, 18-54 years; 10 men) who underwent pylorus evaluation using 12- cm FLIP placed across the pyloric sphincter. FLIP data were analyzed using FLIP planimetry plots at baseline and after administration of hyoscine butyl bromide injection.

Results

The median pylorus distensibility index (P-DI) was 8.37 mm²/mmHg (interquartile range, 4.22-13.04 mm²/mmHg) at 40 mL balloon volume. The 90th percentile at 40 mL balloon for P-DI was 14.89 mm²/mmHg, for cross-sectional area was 244.20 mm²/mmHg, and diameter and pressure were 17.58 mm and 48.84 mmHg, respectively. There was significant increase in P-DI after administration of hyoscine butyl bromide injection (P < 0.05).

Conclusion

The normative values can be used as reference values for pyloric distensibility. This reference can be used in studies of related to pyloric diseases such as gastroparesis.

Small Bowel Dysmotility, Pseudoobstruction, and Functional Correlation with Histopathology: Lessons Learned

PURPOSE OF REVIEW

Small bowel dysmotility is a broad heterogeneous term that encompasses a wide range of gastrointestinal disorders resulting from abnormal gut motility. Chronic intestinal pseudo-obstruction (CIPO) is a severe, rare, and complex small bowel motility disorder at the extreme end of this spectrum. It is characterized by failure of the intestinal tract to propel contents, which results in signs and symptoms of bowel obstruction albeit in the absence of any obstructive lesion(s). In this article, we discuss up-to-date diagnostic techniques, management options, and histopathological findings in CIPO.

RECENT FINDINGS

We will emphasize the latest diagnostic methodologies and therapeutic options as well as enteric histopathologic abnormalities in patients with CIPO. CIPO continues to be a clinical challenge. Several novel pharmacological agents hold promise including gastrointestinal hormone agonists and prokinetics. Furthermore, histopathologic findings may help guide therapy and provide further prognostic significance. At present, nutritional support, symptom management, and avoidance of long-term complications are the mainstay of treatment in CIPO.

Detecting the effects of a standardized meal challenge on small bowel motility with MRI in prepared and unprepared bowel

OBJECTIVE

MRI is increasingly used to evaluate small bowel contractility. The objective of this study was to validate a clinically practical stimulation test (300-kcal meal) for small bowel motility.

METHODS

Thirty-one healthy subjects underwent dynamic MRI to capture global small bowel motility after ±10h fasting, of which 15 underwent bowel preparation consisting of 1 L 2.5% mannitol solution and 16 did not. Each subject underwent (1) a baseline motility scan (2) a food challenge (3) a post-challenge scan, and (4) second post-challenge scan (after ±20 minutes). This protocol was repeated within 2 weeks. Motility was quantified using a validated motility assessment technique.

KEY RESULTS

Motility in prepared subjects at baseline was significantly higher than motility in unprepared subjects (0.36 AU vs 0.18 AU, P < 0.001). In the prepared group, the food challenge produced an 8% increase in motility (P = 0.33) while in the unprepared subjects a significant increase of 30% was observed (P < 0.001). Responses to food remained insignificant (P = 0.21) and significant (P = 0.003), for the prepared and unprepared subjects, respectively, ±20 minutes post food challenge. These results were confirmed in the repeated scan session.

CONCLUSION & INFERENCES

A significant response to a 300-kcal meal was measured within 10 minutes in unprepared bowel, supporting the clinical use of this challenge to provoke and assess motility changes. A caloric challenge did not produce an observable increase in motility in mannitol prepared subjects.

Helping Patients with Gastroparesis

Gastroparesis is an increasing concern and options remain limited. Diagnosis hinges on recognition of delayed gastric emptying in the absence of mechanical obstruction. Nontransit studies evaluating gastric motility serve a complementary role and may help guide therapy. Treatment consists of a combination of lifestyle and dietary medication, medications (antiemetics, prokinetics, neuromodulators, and accommodation-enhancers), alternative and complementary therapy, endoscopic therapy (pyloric-directed therapy, temporary stimulation, jejunostomy, or venting gastrostomy) and surgical therapy (pyloroplasty, gastric electrical stimulation, gastrectomy). Treatment can be tailored to the individual needs and symptoms of the affected patient.

An ANMS-NASPGHAN consensus document on esophageal and antroduodenal manometry in children

BACKGROUND

Upper gastrointestinal symptoms in children are common and motility disorders are considered in the differential diagnosis. High resolution esophageal manometry (HRM) has revolutionized the study of esophageal physiology, and the addition of impedance has provided new insights into esophageal function. Antroduodenal motility has provided insight into gastric and small bowel function.

PURPOSE

This review highlights some of the recent advances in pediatric esophageal and antroduodenal motility testing including indications, preparation, performance, and interpretation of the tests. This update is the second part of a two part series on manometry studies in children (first part was on anorectal and colonic manometry [Neurogastroenterol Motil. 2016;29:e12944]), and has been endorsed by the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) and the American Neurogastroenterology and Motility Society (ANMS).

Regional gastrointestinal contractility parameters using the wireless motility capsule: inter-observer reproducibility and influence of age, gender and study country

BACKGROUND

The wireless motility capsule concurrently measures temperature, pH and pressure as it traverses the gastrointestinal tract.

AIMS

To describe normative values for motility/contractility parameters across age, gender and testing centres.

METHODS

Healthy participants underwent a standardised wireless motility capsule assessment following an overnight fast and consumption of a meal of known nutritional content. Traces were divided into regions of interest and analysed using 2 software packages (MotiliGI and GIMS Data Viewer). Inter-observer agreement was independently assessed by 2 investigators.

RESULTS

Normative data for motility/contractility parameters (maximum amplitude, mean peak amplitude, contraction frequency and motility index) are presented for 107 individuals (62 male, median age 40 years, range 18-78). MotiliGI-Gastric, small bowel and colonic maximal contraction amplitude correlated with age (r = .24, P = .01; r = .22, P = .02; and r = .2, P = .04 respectively). Small bowel motility index was higher in females than males (150.4 ± 12 vs 122 ± 7.6, P = .04). Inter-observer agreement was excellent for transit times, pH and contractility/motility parameters. GIMS Data viewer-Gastric, small bowel and colonic log_e motility index correlated with the respective area under the contraction curve, total contractions, sum of amplitudes and contraction frequency (all r>.35, P < .0003) but not with transit times.

CONCLUSIONS

Our analysis provides normative data for motility/contractility parameters. Log motility index summarises a number of measures. In future, the measurement of contractile activity with the wireless motility capsule may potentially aid in the diagnosis of disease states such as visceral myopathic disorders.

Established and emerging methods for assessment of small and large intestinal motility

BACKGROUND

Gastrointestinal symptoms are common in the general population and may originate from disturbances in gut motility. However, fundamental mechanistic understanding of motility remains inadequate, especially of the less accessible regions of the small bowel and colon. Hence, refinement and validation of objective methods to evaluate motility of the whole gut is important. Such techniques may be applied in clinical settings as diagnostic tools, in research to elucidate underlying mechanisms of diseases, and to evaluate how the gut responds to various drugs. A wide array of such methods exists; however, a limited number are used universally due to drawbacks like radiation exposure, lack of standardization, and difficulties interpreting data. In recent years, several new methods such as the 3D-Transit system and magnetic resonance imaging assessments on small bowel and colonic motility have emerged, with the advantages that they are less invasive, use no radiation, and provide much more detailed information.

PURPOSE

This review outlines well-established and emerging methods to evaluate small bowel and colonic motility in clinical settings and in research. The latter include the 3D-Transit system, magnetic resonance imaging assessments, and high-resolution manometry. Procedures, indications, and the relative strengths and weaknesses of each method are summarized.

Effects of Chinese herbal medicine Xiangbin prescription on gastrointestinal motility

AIM

To investigate the effects of Xiangbin prescription (XBP), a Chinese herbal concoction, on gastrointestinal motility.

METHODS

Forty healthy volunteers were recruited for this randomized controlled trial of XBP. Antroduodenojejunal manometry was used to monitor gastrointestinal motility in these subjects. After the subjects had fasted for at least 12 h, XBP (n = 30) or placebo (n = 10) was orally administrated and gastrointestinal motility was recorded for 4 h. Plasma motilin and ghrelin were measured by enzyme-linked immunosorbent assay.

RESULTS

Oral administration of XBP significantly increased the amplitude of duodenal contractions [19.5 (13.0-26.7) vs 16.9 (12.3-23.9), P < 0.05], jejunal contractions [18.3 (15.3-25.0) vs 15.4 (11.7-23.9), P < 0.01], and the motility index of duodenal contractions [522.0 (146.0-139.0) vs 281.0 (76.5-1006.0), P < 0.01] in phase II of the migratory motor complex (MMC), which subsequently initiated the MMC cycle [74.0 (30.0-118.0) vs 116.5 (24.0-219.0), P < 0.05], shortened the duration of phase I of the MMC [42.0 (0.0-90.0) vs 111.5 (42.0-171.0), P < 0.01], and lengthened the duration of phase II of the MMC [120 (21-240) vs 58 (16-170), P < 0.01] compared to the duration before XBP administration. There were significant differences in the amplitude of jejunal contractions [19.8 (14.0-30.0) vs 18.0 (13.0-28.5), P < 0.05], the motility index of duodenal contractions [236.0 (115.0-306.0) vs 195.0 (109.0-310.0), P < 0.05)], and jejunal contractions [214.0 (95.0-403.0) vs 178.0 (55.0-304.0), P < 0.01] in phase III of the MMC. Oral administration of XBP greatly increased plasma motilin (57.69 ± 9.03 vs 49.38 ± 8.63, P < 0.01) and ghrelin (279.20 ± 104.31 vs 238.73 ± 115.59, P < 0.01) concentrations compared to concentrations after oral administration of the placebo.

CONCLUSION

XBP can stimulate duodenal and jejunal motility and increase the concentrations of plasma motilin and ghrelin. The clinical applicability of XBP in treating GDIM deserves investigation.

Pyloric Therapies for Gastroparesis

OPINION STATEMENT

Gastroparesis is a syndrome that can be difficult to treat effectively and likely represents the common clinical presentation of multiple underlying mechanisms. One of these presumed mechanisms involves pyloric dysfunction, tied perhaps to spasm or fibrosis, manifesting as functional gastric outlet obstruction. Various diagnostic modalities have been used to better characterize this hypothesized abnormality, including most recently antroduodenal manometry and impedance planimetry. A variety of therapeutic interventions specific to the pylorus have also been proposed in the last several years, including intrapyloric injections of botulinum toxin, transpyloric stenting, surgical pyloroplasty, and endoscopic pyloromyotomy. The clinical application of these maneuvers has been mostly empiric thus far, but efforts are ongoing to identify the subset of patients whose physiology best positions them to benefit from such therapy. Early results for many of these interventions have been promising and will serve as the basis for larger and more systematic research frameworks moving forward.

Antroduodenal Manometry Is Abnormal in Children Presenting With Orthostatic Intolerance and Gastrointestinal Symptoms

OBJECTIVES

Gastrointestinal (GI) symptoms of nausea, vomiting, and abdominal pain are common in patients with orthostatic intolerance (OI), including neurally mediated hypotension (NMH) and postural orthostatic tachycardia syndrome (POTS). Autonomic dysregulation is considered the underlying pathophysiology behind the cardiovascular symptoms of POTS. Because the autonomic nervous system also regulates GI motility, we hypothesized that patients with POTS and GI symptoms will have evidence of autonomic dysmotility of the upper GI tract.

METHODS

Thirty-five subjects with OI and GI symptoms were studied. All the subjects had a 24-hour antroduodenal manometry (ADM) study, in conjunction with pharmacologic challenge and autonomic and tilt table testing (TTT).

RESULTS

The mean subject age was 16.2 ± 2.8 years (range 10-23.8 years), and male to female ratio was 10:25. TTT was abnormal in all the 35 subjects, whereas Valsalva testing was abnormal (+40 mmHG) in 21 of 34 (62%) subjects, and corrected QT interval was ≥0.44 seconds in 19 of 35 (54%) subjects. During TTT, GI symptoms were reproduced in 31 of 35 (89%) studies. ADM was found to be abnormal at baseline, before the TTT in 5 of 35 (14%) subjects, whereas it became abnormal in 23 of 34 (68%) subjects during TTT. In addition, the expected response to the pharmacologic challenge was limited. Overall, ADM was abnormal in 26 of 35 (74%) patients either at baseline or during TTT in these subjects with OI.

CONCLUSIONS

ADM is frequently abnormal in children with OI and GI symptoms. Upper GI motility studies should be a part of the comprehensive evaluation in this population.

Computational postprocessing quantification of small bowel motility using magnetic resonance images in clinical practice: An initial experience

PURPOSE

To study the feasibility and to gauge the potential clinical impact of quantifying small bowel motility using magnetic resonance imaging (MRI) in a larger population with a spectra of gastrointestinal conditions with impaired small bowel motility.

MATERIALS AND METHODS

Data were gathered retrospectively from a cohort of 127 patients undergoing MR enterography (1.5 Tesla) in 2011. Cine motility sequences were processed with validated motility analysis software and a parametric motility map was generated. Regions of interests were drawn in the jejunum, ileum, and terminal ileum, and Jacobian standard deviation mean motility index' score (MIS) was calculated. Patients were divided into Crohn's disease (CD), ulcerative colitis, irritable bowel syndrome, and healthy subjects.

RESULTS

In CD, terminal ileum motility was lower in comparison to healthy subjects (mean difference: -0.1052 arbitrary units, 95% confidence interval: -0.1981--0.0122, P = 0.018). Subgrouping of CD showed that the difference was recognized in patients with disease limited to the small bowel (mean difference: -0.1440 arbitrary units, 95% confidence interval: -0.2491--0.0389, P = 0.002). Visible dysmotility of terminal ileum on MRI reflected a reduced MIS compared with normal motility (0.22 ± 0.09 and 0.33 ± 0.15 arbitrary units, respectively, P = 0.043). Motility correlated negatively between ileum and age (P = 0.021), and between terminal ileum and C-reactive protein in ulcerative colitis (P = 0.031).

CONCLUSION

Motility quantitation revealed a significant difference in motility of terminal ileum in patients with small bowel CD compared with healthy subjects, concording with visible dysmotility and inflammatory changes. J. Magn. Reson. Imaging 2016;44:277-287.

Gastroparesis in children

PURPOSE OF REVIEW

Gastroparesis is a disorder with delayed gastric emptying in the absence of mechanical obstruction. It is one of the more common dysmotilities that occur in the gastrointestinal tract, and is thought to primarily affect adults. Pediatric cases of gastroparesis were considered rare; however, recent evidence suggests growing recognition in children and adolescents. Therefore, it is important for the pediatric caregiver to understand the condition and the treatment options available.

RECENT FINDINGS

The majority of patients are women, and presentation is usually with symptoms of persistent nausea, emesis, postprandial pain and bloating, and early satiety. Weight loss may occur in some cases, though this is not universal. The majority of cases are idiopathic, with diabetes mellitus the second most common cause.

SUMMARY

Treatment consists of symptomatic relief with medication to counteract the nausea, emesis, pain, bloating, gastroesophageal reflux, early satiety, and improve gastric emptying. Dietary modification is also used with small meals and avoidance of high fiber and fat-containing foods. Recalcitrant cases of gastroparesis require the use of additional approaches such as jejunal feeds, intrapyloric botulinum toxin, gastric emptying procedures such as pyloroplasty, and gastric electrical stimulation. We will review these options in this article.

Motility alterations in celiac disease and non-celiac gluten sensitivity

Regulation of gut motility is complex and involves neuromuscular, immune and environmental mechanisms. It is well established that patients with celiac disease (CD) often display gut dysmotility. Studies have shown the presence of disturbed esophageal motility, altered gastric emptying, and dysmotility of the small intestine, gallbladder and colon in untreated CD. Most of these motor abnormalities resolve after a strict gluten-free diet, suggesting that mechanisms related to the inflammatory condition and disease process are responsible for the motor dysfunction. Motility abnormalities are also a hallmark of functional bowel disorders such as irritable bowel syndrome (IBS), where it has been proposed as underlying mechanism for symptom generation (diarrhea, constipation, bloating). Non-celiac gluten sensitivity (NCGS) is a poorly defined entity, mostly self-diagnosed, that presents clinically with IBS symptoms in the absence of specific celiac markers. Patients with NCGS are believed to react symptomatically to wheat components, and some studies have proposed the presence of low-grade inflammation in these patients. There is little information regarding the functional characterization of these patients before and after a gluten-free diet. A study suggested the presence of altered gastrointestinal transit in NCGS patients who also have a high prevalence of nonspecific anti-gliadin antibodies. Results of an ongoing clinical study in NCGS patients with positive anti-gliadin antibodies before and after a gluten-free diet will be discussed. Elucidating the mechanisms for symptom generation in NCGS patients is important to find new therapeutic alternatives to the burden of imposing a strict gluten-free diet in patients who do not have CD.

Duodenal rather than antral motility contractile parameters correlate with symptom severity in gastroparesis patients

BACKGROUND

Studies of symptomatic gastroparetics consistently find poor correlation with gastric emptying. We hypothesized that concomitant small bowel dysmotility may play a role in symptom causation in gastroparesis and sought to test this hypothesis by using wireless motility capsule (WMC) testing to simultaneously measure antral and duodenal area under pressure curve (AUC) in patients with delayed gastric emptying.

METHODS

Using a cohort from a multicenter clinical trial and a separate tertiary clinical database, we identified gastroparetics that underwent concurrent WMC testing and completed the Gastroparesis Cardinal Symptom Index, a validated questionnaire. Our study included 35 gastroparetics defined by a gastric emptying time (GET) ≥ 5 h. Antral and duodenal AUC were assessed at 1-h windows pre-GET and post-GET, respectively.

KEY RESULTS

We found moderate correlations between duodenal AUC and symptom severity in the combined cohort (n = 35; R = -0.42; p = 0.01; 95% CI -0.7, -0.1). Removing patients with colonic delay resulted in a stronger correlation of duodenal AUC to symptom severity (n = 21; R = -0.63; p < 0.01; 95% CI -0.81, -0.31). The multicenter trial (n = 20) and clinical practice cohorts (n = 15) had significantly different symptom severity and exclusion criteria. When analyzed separately, significant correlations between duodenal AUC and symptom severity were observed (R = -0.71; p < 0.01; 95% CI -0.9, -0.4 and R = -0.72; p < 0.01; 95% CI -0.9, -0.3, respectively). Symptom severity and antral motility showed no correlation.

CONCLUSIONS & INFERENCES

We found significant correlations between duodenal AUC and symptom severity in two cohorts of gastroparetics. Small bowel motility may contribute to symptom generation in gastroparetic patients and this may inform therapeutic considerations.

Intestinal manometry: who needs it?

The use of manometry, i.e. the recording of pressures within hollow viscera, after being successfully applied to the study of esophageal and anorectal motor dysfunctions, has also been used to investigate physiological and pathological conditions of the small bowel. By means of this technique, it has been possible to understand better the normal motor functions of the small intestine, and their relationship and variations following physiologic events, such as food ingestion. Moreover, intestinal manometry has proved useful to document motor abnormalities of the small bowel, although recognition of altered patterns specific for a determinate pathologic condition is still unavailable. However, this technique often permits the detection of abnormal gut motility in patients with abdominal symptoms such as unexplained vomiting and diarrhea, and it is sometimes also useful to address therapeutic targeting.

Gastrointestinal motility revisited: The wireless motility capsule

INTRODUCTION

The wireless motility capsule (WMC) is a novel ambulatory technology that concurrently measures intraluminal pH, temperature, and pressure as it traverses the gastrointestinal tract.

OBJECTIVES

We aim to provide a concise summary of the WMC, detailing the procedure for its administration and the parameters it records. We also review the evidence that has validated the WMC against other methods currently regarded as 'gold standard'.

CONCLUSIONS

The WMC offers a number of advantages over and above current techniques, especially with respect to patient tolerability, safety, and standardization. The WMC represents a considerable enhancement of the researchers' and clinicians' investigatory armamentarium. If this technology becomes widely adopted, coupled with international consensus upon the interpretation of physiological data derived therein, it may herald a new and exciting era in gastrointestinal physiology.