Intra- and interrater reliability of the Chicago Classification of achalasia subtypes in pediatric high-resolution esophageal manometry (HRM) recordings

BACKGROUND

Subtyping achalasia by high-resolution manometry (HRM) is clinically relevant as response to therapy and prognosis have shown to vary accordingly. The aim of this study was to assess inter- and intrarater reliability of diagnosing achalasia and achalasia subtyping in children using the Chicago Classification (CC) V3.0.

METHODS

Six observers analyzed 40 pediatric HRM recordings (22 achalasia and 18 non-achalasia) twice by using dedicated analysis software (ManoView 3.0, Given Imaging, Los Angeles, CA, USA). Integrated relaxation pressure (IRP4s), distal contractile integral (DCI), intrabolus pressurization pattern (IBP), and distal latency (DL) were extracted and analyzed hierarchically. Cohen's κ (2 raters) and Fleiss' κ (>2 raters) and the intraclass correlation coefficient (ICC) were used for categorical and ordinal data, respectively.

RESULTS

Based on the results of dedicated analysis software only, intra- and interrater reliability was excellent and moderate (κ=0.89 and κ=0.52, respectively) for differentiating achalasia from non-achalasia. For subtyping achalasia, reliability decreased to substantial and fair (κ=0.72 and κ=0.28, respectively). When observers were allowed to change the software-driven diagnosis according to their own interpretation of the manometric patterns, intra- and interrater reliability increased for diagnosing achalasia (κ=0.98 and κ=0.92, respectively) and for subtyping achalasia (κ=0.79 and κ=0.58, respectively).

CONCLUSIONS

Intra- and interrater agreement for diagnosing achalasia when using HRM and the CC was very good to excellent when results of automated analysis software were interpreted by experienced observers. More variability was seen when relying solely on the software-driven diagnosis and for subtyping achalasia. Therefore, diagnosing and subtyping achalasia should be performed in pediatric motility centers with significant expertise.

Assessment of bolus transit with intraluminal impedance measurement in patients with esophageal motility disorders

BACKGROUND

The clinical management of patients with non-obstructive dysphagia is notoriously difficult. Esophageal impedance measurement can be used to measure esophageal bolus transit without the use of radiation exposure to patients. However, validation of measurement of bolus transit with impedance monitoring has only been performed in healthy subjects with normal motility and not in patients with dysphagia and esophageal motility disorders. The aim was, therefore, to investigate the relationship between transit of swallowed liquid boluses in healthy controls and in patients with dysphagia.

METHODS

Twenty healthy volunteers and 20 patients with dysphagia underwent concurrent impedance measurement and videofluoroscopy. Each subject swallowed five liquid barium boluses. The ability of detecting complete or incomplete bolus transit by means of impedance measurement was assessed, using radiographic bolus transit as the gold standard.

KEY RESULTS

Impedance monitoring recognized stasis and transit in 80.5% of the events correctly, with 83.9% of bolus transit being recognized and 77.2% of stasis being recognized correctly. In controls 79.8% of all swallows were scored correctly, whereas in patients 81.3% of all swallows were scored correctly. Depending on the contractility pattern, between 77.0% and 94.3% of the swallows were scored correctly.

CONCLUSIONS & INFERENCES

Impedance measurement can be used to assess bolus clearance patterns in healthy subjects, but can also be used to reliably assess bolus transit in patients with dysphagia and motility disorders.

Sensation of stasis is poorly correlated with impaired esophageal bolus transport

BACKGROUND

It is common belief that symptoms of patients with non-obstructive dysphagia are the result of impaired bolus clearance in the esophagus, usually caused by esophageal motility disorders. We therefore investigated the relationship between transit of swallowed boluses and the symptom dysphagia.

METHODS

Twenty healthy volunteers and 20 patients with dysphagia underwent videofluoroscopy. Success of bolus transport was graded on a 7-point scale. Each subject swallowed five liquid and five solid barium boluses.

KEY RESULTS

For liquids, patients reported dysphagia during 1 [0-3] of the five swallows, while controls reported no dysphagia (median 0 [0-0]; p = 0.003). For solids, patients reported dysphagia during 3 [2-4] of five swallows, while controls reported dysphagia in 0.5 [0-2] of five swallows (p = 0.001). When correlating dysphagia to ineffective clearance (score ≥ 3), in 3 [2-4] of five liquids, the subjects perception of clearance was related to the clearance result on fluoroscopy in patients and also 3 [1-5] were correctly perceived in controls (p = 0.6). For solids, in 4 [3-5] of five swallows, the subjects perception of clearance was related to the clearance result on fluoroscopy in patients, but only 2 [1-3] of five swallows were correctly perceived by controls, the difference being statistically significant.

CONCLUSIONS & INFERENCES

Patients very frequently report dysphagia when bolus clearance is successful. Therefore, the major underlying problem in patients with non-obstructive dysphagia is disordered perception and increased sensitivity to physiological bolus stasis. Treatment should therefore be directed at reducing increased sensitivity rather than at improving motility.

Normal values for esophageal high-resolution manometry

BACKGROUND

Esophageal high-resolution manometry (HRM) is a novel method to assess esophageal motility. Several software and hardware systems are currently available. A set of normal values for HRM parameters was established in the US, using proprietary tactile-sensing catheter technology (Given Imaging). We wished to determine normal values for HRM performed with another type of catheter (Unisensor).

METHODS

Fifty-two healthy volunteers underwent supine HRM. Each subject swallowed 10 liquid water boluses. Esophageal contraction parameters were evaluated and normal values were calculated (defined as 5th and 95th percentile of values).

KEY RESULTS

The normal range for the following parameters was calculated; distal contractile integral (mean 1319.44, with a 5-95th percentile range [185.65-3407.60]), contractile front velocity (mean 3.98, 5-95th percentile range [2.40-6.50]), Intrabolus pressure (mean 9.68, range [1.00-19.00]), contraction amplitude measured 5 cm above the esophagogastric junction (EGJ; mean 78.76, range [23.00-146.00]), contraction amplitude 15 cm above the EGJ (mean 43.66, range [3.60-96.00]), transition zone (TZ) length (mean 1.34, range [0.00-5.63]), upper esophageal sphincter (UES) pressure (mean 81.63, range [19.50-165.10]), EGJ length (mean 2.97, range [2.17-4.00]), EGJ resting pressure (mean 29.35, range [8.95-51.40]), EGJ relaxation pressure (mean 16.79, range [1.00-39.35]), IRPs4 (mean 13.42, range [2.59-28.28]), and gastric pressure (mean 5.06, range [0.00-9.46]).

CONCLUSIONS & INFERENCES

Overall, the normal values of esophageal HRM parameters obtained with the Unisensor catheter resemble those of the previously published series. Marked differences in upper limits of normal were found for parameters related to the esophageal sphincters and TZ length. Users of HRM should be aware of these differences and define pathology based on comparison to appropriate normal values.

Relationship between esophageal contraction patterns and clearance of swallowed liquid and solid boluses in healthy controls and patients with dysphagia

BACKGROUND

Non-obstructive dysphagia patients prove to be a difficult category for clinical management. Esophageal high-resolution manometry (HRM) is a novel method, used to analyze dysphagia. However, it is not yet clear how findings on HRM relate to bolus transport through the esophagus.

METHODS

Twenty healthy volunteers and 20 patients with dysphagia underwent HRM and videofluoroscopy in a supine position. Each subject swallowed five liquid and five solid barium boluses. Esophageal contraction parameters and bolus transport were evaluated with HRM and concurrent videofluoroscopy.

KEY RESULTS

Stasis of liquid and solid barium boluses occurred in patients and in healthy volunteers in 64% and 41% and in 84% and 82% of the swallows, respectively. Overall, 70% of the liquid and 72% of the solid bolus swallows were followed by a peristaltic contraction, the difference not being statistically significant. Statistically significant associations were found for transition zone length of liquid and solid boluses, and for DCI and distal contraction amplitudes for liquid stasis. No correlation was found between the degree of stasis and other manometric parameters.

CONCLUSIONS & INFERENCES

Stasis of both liquid and solid boluses occurs frequently in patients and in controls and can be regarded as physiological. Motility patterns can predict the effectiveness of bolus transit and level of stasis to some degree but the relationship between esophageal motility and transit is complex and far from perfect. Esophageal manometry is therefore currently deemed unfit to be used for the prediction of bolus transit, and should rather be used for the identification of treatable esophageal motility disorders.

Duodenal lipid-induced symptom generation in gastroesophageal reflux disease: role of apolipoprotein A-IV and cholecystokinin

BACKGROUND

  Duodenal lipid intensifies the perception of esophageal acid perfusion. Recently, we showed that genes implicated in lipid absorption were upregulated in the duodenum of fasting gastro-esophageal reflux disease (GERD) patients. This suggests that chylomicron production and secretion may be enhanced and, consequently, the release of apolipoprotein A-IV (apoA-IV), a chylomicron-derived signaling protein. ApoA-IV may stimulate release of cholecystokinin (CCK), an activator of vagal afferents. This study evaluated putative involvement of abnormal apoA-IV and CCK responses to lipid in GERD.

METHODS

  Ten GERD patients and 10 healthy volunteers (HV) underwent duodenal perfusion with Intralipid 20%, 2 kcal min(-1) , for 60 min. Symptoms were scored, blood samples collected every 15 min during lipid perfusion and 15 min after discontinuation when duodenal biopsies were taken. Plasma and mucosal concentrations of apoA-IV and CCK and transcript levels of 21 genes implicated in lipid absorption, differentially expressed under fasting conditions, were quantified.

KEY RESULTS

  Heartburn (P = 0.003), abdominal discomfort (P = 0.037) and nausea (P = 0.008) only increased significantly during lipid infusion in GERD patients. Following lipid infusion mean mucosal apoA-IV concentration was lower in GERD patients compared with HV (P = 0.023), whereas plasma concentration tended to be elevated (P = 0.068). Mean mucosal CCK concentration was also lower in GERD patients (P = 0.009). Two genes, HIBADH and JTB, were upregulated in GERD patients (P = 0.008 and P = 0.038, respectively).

CONCLUSIONS & INFERENCES

  Our results suggest excessive duodenal lipid-induced release of apoA-IV and CCK in GERD. We postulate that the resulting heightened activation of duodenal vagal afferents may underlie central sensitization, thereby increasing the perception of reflux events.

Reproducibility of esophageal high-resolution manometry

BACKGROUND

  Esophageal high-resolution manometry (HRM) is a novel method for esophageal function testing that has prompted the development of new parameters for quantitative analysis of esophageal function. Until now, the reproducibility of these parameters has not been investigated.

METHODS

Twenty healthy volunteers underwent HRM on two separate days. Standard HRM parameters were measured. In addition, in conventional (virtual) line tracings, lower esophageal sphincter (LES) resting pressure, relaxation pressure, and relative relaxation pressure were measured. Firstly, for each variable, the mean percentage of covariation (100×SD/mean: %COV) was derived as a measure of inter- and intra-individual variation. Secondly, Kendall's coefficients of concordance (W values) were calculated. Thirdly, Bland-Altman plots were used to express concordance graphically.

KEY RESULTS

Statistically significant concordance values were found for upper esophageal sphincter (UES) pressure (W=0.90, P=0.02), transition zone length (W=0.92, P=0.01), LES length (W=0.81, P=0.04), LES pressure (W=0.75, P=0.05), LES relaxation pressure (W=0.75, P=0.03), relative LES relaxation pressure (W=0.78, P=0.05), gastric pressure (W=0.81, P=0.04), and contraction amplitude 5cm above the LES (W=0.86, P=0.03). In conventional setting, only LES resting pressure (W=0.835, P=0.03) proved significant. In HRM tracings, concordance values for contraction wave parameters, and in conventional line tracings, LES relaxation pressure and relative relaxation pressure did not reach levels of statistical significance.

CONCLUSIONS & INFERENCES

Esophageal HRM yields reproducible results. Parameters that represent anatomic structures show better reproducibility than contraction wave parameters. The reproducibility of LES resting and relaxation pressure assessed with HRM is better than with conventional manometry and further supports the clinical use of HRM.

Impaired bolus transit across the esophagogastric junction in postfundoplication dysphagia

OBJECTIVES

This study assessed the effect of fundoplication on liquid and solid bolus transit across the esophagogastric junction (EGJ) in relation to EGJ dynamics and dysphagia.

METHODS

Twelve patients with gastro-esophageal reflux disease (GERD) were studied before and after fundoplication. Concurrent high-resolution EGJ manometry and fluoroscopy were performed whilst swallowing liquid barium and a solid bolus. The EGJ transit time, EGJ opening duration, transit efficacy, and EGJ relaxation were measured. During the test symptoms of dysphagia were scored using a visual analog scale.

RESULTS

The minimal opening aperture at fluoroscopy was located at the manometric EGJ in all subjects. Fundoplication markedly reduced the EGJ opening diameter from 1.0 +/- 0.1 to 0.6 +/- 0.1 cm (p < 0.01) and rendered deglutative EGJ relaxation incomplete. After fundoplication, a higher intrabolus pressure was found (p < 0.05) associated with a reduced axial bolus length (p < 0.001). EGJ transit time increased from 6.9 +/- 0.9 to 9.8 +/- 1.0 s for liquids (p < 0.01) and from 2.8 +/- 0.5 to 5.8 +/- 0.8 s (p < 0.01) for solids after fundoplication. No relation between EGJ transit and dysphagia scores was observed before fundoplication. In contrast, EGJ transit time significantly correlated with dysphagia scores both during liquid (r = 0.84; p < 0.01) and solid (r = 0.69; p < 0.05) bolus transit following fundoplication.

CONCLUSIONS

Fundoplication patients exhibit a restricted hiatal opening and an incomplete deglutative EGJ relaxation. To facilitate EGJ transit despite these altered EGJ dynamics a higher intrabolus pressure is created by augmented bolus compression. Fundoplication increases EGJ transit time, the degree of which is associated with postoperative dysphagia.

Interdigestive transpyloric fluid transport assessed by intraluminal impedance recording

Our aim was to explore the use of intraluminal impedance recording for assessment of interdigestive transpyloric fluid movements. Twenty healthy volunteers were studied with a catheter allowing the recording of five antropyloroduodenal impedance signals simultaneously with six pressure signals. Patterns induced by air were verified by standard ultrasound. Transpyloric Doppler ultrasound was used to validate impedance patterns associated with transpyloric fluid transports. Impedance changes caused by air (short-lived increases) occupied 14 +/- 12% of the time in the antrum and 0.8 +/- 0.5% in the duodenum (P < 0.005). All fluid transport events lasting >4 s were recorded by both Doppler and impedance techniques. Transpyloric fluid transport was observed in all three phases of the antral migrating motor complex. The total number of transport events was significantly higher (P < 0.05) in phase II (18 +/- 7) than in phases I (2.6 +/- 2) and III (6.1 +/- 3). Retrograde transport was observed mainly in antral phase I (54% of fluid movements, compared with 2.5% in phase II and 18.5% in phase III, P < 0.05). During phase II, 80 +/- 13% of the impedance changes were associated with manometric events and 72 +/- 9% of the antral contractions were associated with transpyloric fluid transport. Prolonged assessment of interdigestive transpyloric fluid transport events using intraluminal measurement of impedance is possible. Manometrically detectable contractions are the most frequent, but not the only, driving forces of these events.