Solid-state High-resolution Manometry Research Articles

A134 UES MANOMETRIC PARAMETERS IN ESOPHAGEAL MOTILITY DISORDERS

BackgroundUpper esophageal sphincter (UES) function may be evaluated manometrically using a solid-state high-resolution manometry (HRM) system, which allows for the measurement of manometric parameters specific to the UES. While many of these parameters have yet to be validated for use in clinical practice, there is some suggestion that there may be an association between esophageal motility and UES function.AimsWe aimed to identify the relationship between UES manometric variables and high-resolution esophageal manometry (HREM) diagnoses.MethodsA retrospective analysis of HREM studies was performed between 2019 and 2021. Extraction of esophageal and UES manometric variables were performed. UES manometric values of interest included: mean basal pressure (mmHg), mean residual pressure (mmHg), relaxation time-to-nadir (ms), relaxation duration (ms), and recovery time (ms). Relationships between manometric diagnosis (Chicago Classification version 3) and UES manometric variables were explored. All values are expressed a medians and group means were compared with the non-parametric Mann-Whitney U test.Results2119 symptomatic patients underwent HREM over the study period. Manometric diagnoses were achalasia (72 patients), esophagogastric junction outflow obstruction (286), absent contractility (108), distal esophageal spasm (53), jackhammer esophagus (32), and ineffective esophageal motility (694). 886 patients had no specific motility disorder; 643 of whom had ≤ 20% ineffective swallows and were considered symptomatic controls.Patients with achalasia had significantly higher mean basal pressures (63.2 vs. 54.4, p = .001), mean residual pressure (3.8 vs. -1.9, p < .001), relaxation-time-to-nadir (182.0 vs. 142.0, p = .005), relaxation duration (820.5 vs. 708.0, p < .001) and recovery time (623.0 vs. 562, p < .001) compared to control patients. Among patients with achalasia, the presence of panesophageal pressurization correlated weakly with recovery time (R2 .3, p = .03). Patients with ineffective esophageal motility had significantly higher mean basal pressures (61.7 vs. 54.0, p < .001).Among all patients, patients with incomplete bolus clearance (≥ 30%) had significantly higher UES mean basal pressure (58.9 vs. 54.6, p = .004), mean residual pressure (-.62 vs. -2, p < .001), relaxation duration (724.0 vs. 707.0, p = .014) and recovery time (580 vs. 558.0, p < .001).ConclusionsPatients with achalasia may have higher basal and residual UES pressures, and slower relaxation compared to patients with normal esophageal motility. This may reflect dynamic changes of the UES in response to obstruction at the esophagogastric junction. Elevated UES pressures are also seen in patients with ineffective esophageal motility, potentially reflecting a response to poor bolus clearance. More work needs to be done to validate these parameters in clinical practice.Funding AgenciesNone

High-resolution colonic manometry interobserver analysis trial.

Colonic high-resolution manometry (HRM) is a novel, not widely used diagnostic method used in the final workup of chronic constipation before surgery. Since its introduction, different motor patterns have been defined. However, it remains to be established whether these patterns are easily and reproducibly identified by different investigators. The primary aim of this study was to determine agreement for motor pattern identification with HRM. To calculate the interobserver agreement (IOA), the Fleiss's kappa statistic for multiple observers was used. Seven participants analyzed 106 one-min time frames, derived from five measurements in healthy volunteers and five in patients with chronic constipation. The time frames were chosen to show a variety and combination of motor patterns consisting of short antegrade, short retrograde, cyclic anterograde, cyclic retrograde, long antegrade, long retrograde, slow retrograde motor pattern, high-amplitude propagating motor patterns, and pancolonic pressurizations. All of the measurements were performed with a solid-state colonic HRM catheter, comprising 40 pressure sensors spaced 2.5cm apart. A median of 10.25h (range 6-20) were required to analyze all time frames. High-amplitude propagating contractions achieved an almost perfect level of agreement (k=0.91). Several motor patterns achieved substantial agreement; these included the short antegrade (k=0.63), long antegrade (k=0.68), cyclic retrograde (k=0.70), slow retrograde motor pattern (k=0.80), and abdominal pressure or movement artifacts (k=0.67). Moderate agreement was found for short retrograde (k=0.57), cyclic anterograde (k=0.59), long retrograde motor patterns (k=0.59) and simultaneous pressure waves (k=0.59). For the majority of motor patterns, the overall IOA for colonic manometry was substantial or high. This high level of agreement supports the use of colonic manometry application in clinical and research settings. Harmonization has the potential to improve agreement for long anterograde motor patterns with high amplitudes and for mixed direction patterns.

Provocative testing in patients with jackhammer esophagus: evidence for altered neural control.

Jackhammer esophagus (JE) is a hypercontractile disorder, the pathogenesis of which is incompletely understood. Multiple rapid swallows (MRS) and rapid drink challenge (RDC) are complementary tests used during high-resolution manometry (HRM) that evaluate inhibitory and excitatory neuromuscular function and latent obstruction, respectively. Our aim was to evaluate esophageal pathophysiology using MRS and RDC in 83 JE patients (28 men; median age: 63 yr; IQR: 54-70 yr). Twenty-one healthy subjects (11 men; median age: 28 yr; range: 26-30 yr) were used as a control group. All patients underwent solid-state HRM with ten 5-ml single swallows (SS) and one to three 10-ml MRS; 34 patients also underwent RDC. Data are shown as median (interquartile range). Abnormal motor inhibition was noted during at least one MRS test in 48% of JE patients compared with 29% of controls ( P = 0.29). Mean distal contractile integral (DCI) after MRS was significantly lower than after SS [6,028 (3,678-9,267) mmHg·cm·s vs. 7,514 (6,238-9,197) mmHg·cm·s, P = 0.02], as was highest DCI ( P < 0.0001). Consequently, 66% of JE patients had no contraction reserve. At least one variable of obstruction during RDC (performed in 34 patients) was outside the normal range in 25 (74%) of JE patients. Both highest DCI after SS and pressure gradient across the esophagogastric junction (EGJ) during RDC were higher in patients with dysphagia versus those without ( P = 0.04 and 0.01, respectively). Our data suggest altered neural control in JE patients with heterogeneity in inhibitory function. Furthermore, some patients had latent EGJ obstruction during RDC, which correlated with the presence of dysphagia. NEW & NOTEWORTHY Presence of abnormal inhibition was observed during multiple rapid swallows (MRS) in some but not all patients with jackhammer esophagus (JE). Unlike healthy subjects, JE patients were more strongly stimulated after single swallows than after MRS. An obstructive pattern was frequently observed during rapid drink challenge (RDC) and was related to presence of dysphagia. MRS and RDC during high-resolution manometry are useful to show individual pathophysiological patterns in JE and may guide optimal therapeutic strategies.

Pressure measurement in the upper esophagus during cricoid pressure: A high-resolution solid-state manometry study.

The use of cricoid pressure is controversial, and its ability to occlude the esophagus has been questioned. In this study, high-resolution solid-state manometry was used to analyze pressure changes in the upper esophagus from cricoid pressure during modified rapid sequence induction. This is a secondary analysis of data from a previous study. Seventeen healthy volunteers participated in a double-blind, randomized, placebo-controlled, cross-over study with primary aim to compare differences in the barrier pressure on the lower esophageal sphincter during rapid sequence induction with or without alfentanil. Standardized cricoid pressure of 30N was applied 2minutes after propolipid injection and held for 15seconds and pressures in the esophagus were measured. Cricoid pressure resulted in a pressure increase of 127±98mmHg (95% CI: 73-182) (placebo) and 123±74mmHg (95% CI: 84-162) (alfentanil) at the level of the upper esophageal sphincter (UES), compared to baseline. The pressure difference around the UES compared to the proximal esophagus during cricoid pressure application was 165±100mmHg (placebo) and 159±87mmHg (alfentanil) (mean±1 SD). This study using high-resolution solid-state manometry under clinically relevant conditions shows that 30N cricoid pressure generates high pressure in the area of the UES, far exceeding the levels previously considered necessary to prevent regurgitation. Additional studies are needed to clarify the effectiveness of cricoid pressure in preventing passive regurgitation before it is rejected as a part of rapid sequence induction.

Normal Values of High-Resolution Manometry in Supine and Upright Positions in a Thai Population.

Although cut-off values used in high-resolution manometry (HRM) to diagnose esophageal motility disorders are based on representative samples of the US population and assume a supine position, differences in population and body positioning can reportedly affect results. To establish normal HRM values for Thai people in both supine and upright positions. Forty-one healthy subjects were recruited, each of whom underwent solid-state HRM with ten 5-mL swallows of water in both the supine and upright positions. Measuring parameters according to the Chicago classification criteria (CC v3.0) were included, for which the mean, median and 5th and 95th percentiles (PCTLs) were calculated. The results corresponded with the CC v3.0 criteria, except for the mean, and 5th PCTL of the distal contractile integral (DCI), which were lower for this population. In the upright position, the mean and median values for DCI, intrabolus pressure and integrated relaxation pressure were significantly decreased, whereas the length of the transitional zone was significantly increased. The limitations of this study include: (1) the relatively low number of participants, (2) the limited recruitment of participants only at Ramathibodi Hospital and (3) the limited recruitment of only young and middle-aged participants. We established normal values for the HRM parameters in a representative sample of the Thai population. Our supine results still prove that the use of the CC v3.0 is preferable. HRM testing in patients measured in the upright position should be analyzed based on the normative values obtained from upright swallow studies.

Effect of intragastric FODMAP infusion on upper gastrointestinal motility, gastrointestinal, and psychological symptoms in irritable bowel syndrome vs healthy controls.

The low fermentable oligo-, di-, mono-saccharides and polyol (FODMAP) diet is a treatment strategy to reduce symptoms of irritable bowel syndrome (IBS). Acute effects of FODMAPs on upper gastrointestinal motility are incompletely understood. Our objectives were to assess the acute effects of intragastric FODMAP infusions on upper gastrointestinal motility and gastrointestinal and psychological symptoms in healthy controls (HC) and IBS patients. A high-resolution solid-state manometry probe and an infusion tube were positioned into the stomach. Fructans, fructose, FODMAP mix, or glucose was intragastrically administered to HC, and fructans or glucose was administered to IBS patients until full satiation (score 0-5), in a randomized crossover fashion. Manometric measurements continued for 3 hours. Gastrointestinal and psychological symptoms were assessed by questionnaires at predefined time points. The study was registered on www.clinicaltrials.gov (NCT02980406). Twenty HC and 20 IBS patients were included. Fructans induced higher postprandial gastric pressures compared with glucose over both groups (P<.001). Bloating, belching, and pain increased more in IBS over both carbohydrates (P<.041). In addition, IBS patients reported more flatulence and cramps compared with HC following fructans (P<.001). Glucose induced more fatigue and dominance compared with fructans (P=.028, P=.001). Irritable bowel syndrome patients reported a higher increase in anger (P=.030) and a stronger decrease in positive affect (P=.021). The upper gastrointestinal motility response varies between carbohydrates. Irritable bowel syndrome patients are more sensitive to fructan infusion, reflected in their higher gastrointestinal symptom scores. Acute carbohydrate infusion can have differential psychological effects in IBS and HC.

Normal values of esophageal pressure responses to a rapid drink challenge test in healthy subjects: results of a multicenter study.

Multiple water swallow is increasingly used as a complementary challenge test in patients undergoing high-resolution manometry (HRM). Our aim was to establish the range of normal pressure responses during the rapid drink challenge test in a large population of healthy subjects. Pressure responses to a rapid drink challenge test (100 or 200mL of water) were prospectively analyzed in 105 healthy subjects studied in nine different hospitals from different countries. Esophageal motility was assessed in all subjects by solid-state HRM. In 18 subjects, bolus transit was analyzed using concomitant intraluminal impedance monitoring. A virtually complete inhibition of pressure activity was observed during multiple swallow: Esophageal body pressure was above 20mm Hg during 1 (0-8) % and above 30mm Hg during 1 (0-5) % of the swallow period, and the pressure gradient across the esophagogastric junction was low (-1 (-7 to 4) mm Hg). At the end of multiple swallow, a postswallow contraction was evidenced in only 50% of subjects, whereas the remaining 50% had non-transmitted contractions. Bolus clearance was completed after 7 (1-30) s after the last swallow, as evidenced by multichannel intraluminal impedance. The range of normal pressure responses to a rapid drink challenge test in health has been established in a large multicenter study. Main responses are a virtually complete inhibition of esophageal pressures with a low-pressure gradient across esophagogastric junction. This data would allow the correct differentiation between normal and disease when using this test.

Effects of Esmolol on the Esophagogastric Junction

Passive regurgitation may occur throughout the perioperative period, increasing the risk for pulmonary aspiration and postoperative pulmonary complications. Hypnotics and opioids, especially remifentanil, that are used during anesthesia have been shown to decrease the pressure in the esophagogastric junction (EGJ), that otherwise acts as a barrier against passive regurgitation of gastric contents. Esmolol, usually used to counteract tachycardia and hypertension, has been shown to possess properties useful during general anesthesia. Like remifentanil, the β-1-adrenoreceptor antagonist may be used to attenuate the stress reaction to tracheal intubation and to modify perioperative anesthetic requirements. It may also reduce the need for opioids in the postoperative period. Its action on the EGJ is however unknown.The aim of this trial was to compare the effects of esmolol and remifentanil on EGJ pressures in healthy volunteers, when administrated as single drugs. Measurements of EGJ pressures were made in 14 healthy volunteers using high-resolution solid-state manometry. Interventions were administered in a randomized sequence and consisted of esmolol that was given IV as a bolus dose of 1 mg/kg followed by an infusion of 10 μg·kg·minute over 15 minutes, and remifentanil with target-controlled infusion of 4 ng/mL over 15 minutes. Interventions were separated by a 20-minute washout period. Analyses of EGJ pressures were performed at baseline, and during drug administration at 2 (T2) and 15 minutes (T15). The primary outcome was the inspiratory EGJ augmentation, while the inspiratory and expiratory EGJ pressures were secondary outcomes. There was no effect on inspiratory EGJ augmentation when comparing remifentanil and esmolol (mean difference -4.0 mm Hg [-9.7 to 1.7]; P= .15). In contrast, remifentanil significantly decreased both inspiratory and expiratory pressures compared to esmolol (-12.2 [-18.6 to -5.7]; P= .003 and -8.0 [-13.3 to -2.8]; P= .006). Esmolol, compared with remifentanil, does not affect EGJ function. This may be an advantage regarding passive regurgitation and esmolol may thus have a role to play in anesthesia where maintenance of EGJ barrier function is of outmost importance.

Evaluation of Esophageal Motor Dysfunction in Patients with End-stage Lung Disease by Applying the Chicago Classification

Introduction: Gastroesophageal reflux disease (GERD) has been implicated in the progression of pulmonary fibrosis and post-transplant bronchiolitis obliterans. Esophageal dysmotility can predispose to GERD. The aim of our study was to evaluate the prevalence of esophageal motility disorders in a group of patients presenting for lung transplant evaluation at our institution. We applied the most recent Chicago Classification 3.0 (CC 3.0) to this cohort. Methods: All patients who presented to our institution for the lung transplant evaluation from September 2012 - September 2015, and had a high-resolution manometry (HRM) as part of their workup, were reviewed. All patients underwent HRM evaluation using solid-state HRM catheter (Sierra scientific instruments) with 36 pressure channels, located 1 cm apart. After an acclimation period of 5 minutes, 10 swallows, each with 5 ml water, were performed. HRM parameters were noted and used to determine CC 3.0. Findings from our cohort were compared to the already published normative data. Results: Eighteen patients (180 swallows) were included in our analysis. Mean age was 55 years (range 18-77); 61% of the patients were male; one patient had chronic obstructive pulmonary disease (COPD) and 17 patients had interstitial lung disease (ILD). Analysis of all 180 swallows showed: 35% failed, 13.3% weak and 51.7% normal. Median lower esophageal pressure (LESP) was also low in our cohort (table 1). When CC 3.0 was applied to the 10 representative swallows for each patient, less than half (44.5%) of them had normal HRM findings (table 2). The frequency of abnormal diagnoses was as follows: achalasia (5.5%); EGJ outflow obstruction (5.5%); absent contractility (16.7%) and ineffective esophageal motility (27.8%). 50% (5/10) of all the patients with esophageal motility disorder were completely asymptomatic clinically. Conclusion: Using the CC 3.0, the majority of patients with end-stage lung disease awaiting lung transplantation fulfill criteria for a motility disorder (55.5%). Most had ineffective esophageal motility or absent contractility. LESP and IRP were also low compared to normative data. Given these common findings, the impact of esophageal dysmotility predisposing, or contributing to reflux related lung injury, requires further evaluation.Table 1: Manometric parameters of all 180 swallowsTable 2: Frequency of HRM diagnoses

The motility of esophageal sphincters during liquid and solid bolus swallows: a multicenter normative value study of high-resolution manometry in China.

It is gradually accepted that solid bolus swallow needs to be added to the procedure of manometry. The motility differences in the upper esophageal sphincter (UES) and lower esophageal sphincter (LES) were not well described. Sierra Scientific Instruments solid-state high-resolution manometry (HRM) system, the most popular HRM system in China, lacks the Chinese normative values for both liquid and solid bolus swallow parameters. The esophageal HRM data of 88 healthy volunteers were analyzed. The parameters of both sphincters in resting stage were summarized and those during solid and liquid swallows were compared. Normative HRM values of sphincter parameters in solid and liquid bolus swallows in China were established. The UES residual pressure of solid bolus swallows was lower than that of liquid bolus (0.3±5.5mm Hg vs 4.8±5.9mm Hg, P=.000). The time parameters of UES relaxation between two types of bolus swallows were similar. In solid bolus swallows, the intrabolus pressure (IBP) (13.8±5.1mm Hg vs 10.9±5.7mm Hg, P=.000) and LES relaxation time (11.0±2.1seconds vs 8.7±1.3seconds, P=.000) were higher. The 4-second integrated relaxation pressure between both bolus swallows was similar. The function of the UES and LES between solid and liquid bolus swallows is different. Chinese HRM parameters are different from the Chicago Classification (http://www.chictr.org.cn, Number ChiCTR-EOC-15007147).

Pressure-Flow Analysis for the Assessment of Pediatric Oropharyngeal Dysphagia

To determine which objective pressure-impedance measures of pharyngeal swallowing function correlated with clinically assessed severity of oropharyngeal dysphagia (OPD) symptoms. Forty-five children with OPD and 34 control children without OPD were recruited and up to 5 liquid bolus swallows were recorded with a solid-state high-resolution manometry with impedance catheter. Individual measures of pharyngeal and upper esophageal sphincter (UES) function and a swallow risk index composite score were derived for each swallow, and averaged data for patients with OPD were compared with those of control children without OPD. Clinical severity of OPD symptoms and oral feeding competency was based on the validated Dysphagia Disorders Survey and Functional Oral Intake Scale. Those objective measures that were markers of UES relaxation, UES opening, and pharyngeal flow resistance differentiated patients with and without OPD symptoms. Patients demonstrating abnormally high pharyngeal intrabolus pressures and high UES resistance, markers of outflow obstruction, were most likely to have signs and symptoms of overt Dysphagia Disorders Survey (OR 9.24, P = .05, and 9.7, P = .016, respectively). Pharyngeal motor patterns can be recorded in children by the use of HRIM and pharyngeal function can be defined objectively with the use of pressure-impedance measures. Objective measurements suggest that pharyngeal dysfunction is common in children with clinical signs of OPD. A key finding of this study was evidence of markers of restricted UES opening.

The biomechanical characteristics of the pharynx in patients with aspiration after radiotherapy for nasopharyngeal carcinoma

Objective To explore the biomechanical characteristics of the pharynx in patients with aspiration after radiotherapy for nasopharyngeal carcinoma (NPC). Methods Clinical data on NPC patients with dysphagia admitted between July 2011 and June 2015 were retrospectively analyzed. Twenty-three patients were found who had received videofluoroscopic swallowing studies (VFSSs) and whose pharyngeal pressure and upper esophageal sphincter (UES) relaxing were tested using high-resolution solid-state manometry (HRM). The cases were divided into an aspiration group and a non-aspiration group according to the VFSS results. Differences in biomechanical parameters between the 2 groups when taking food of different viscosity were compared. Results Patients with aspiration had significantly higher UES residual pressure when taking thick liquids (20.1±14.3 mmHg) and paste (18.0±14.3 mmHg) than patients not aspirating (9.3±9.2 mmHg and 7.2±8.9 mmHg for thick liquid and paste respectively). But no significant difference in average pharyngeal pressure between the two groups was observed. Conclusion Aspiration after radiotherapy may be correlated with increased UES residual pressure. Key words: Dysphagia; Aspiration; Nasopharyngeal carcinoma; Radiotherapy

PP‐10 CHARACTERIZATION OF ESOPHAGEAL MOTILITY IN INFANTS BORN WITH CONGENITAL DIAPHRAGMATIC HERNIA USING HIGH RESOLUTION MANOMETRY

Purpose:Congenital diaphragmatic hernia (CDH) is a rare condition characterized by a congenital defect in the diaphragm. Abdominal organs are displaced into the thorax through the diaphragmatic defect, hereby causing lung hypoplasia. Survivors also present with long‐term functional gastro‐intestinal morbidity such as gastro‐esophageal reflux, esophageal dysfunction and poor nutritional status. Congenital esophageal dysmotility and surgical disruption of the esophago‐gastric junction (EGJ) may contribute to this esophageal dysfunction. The aim of this study was to characterize esophageal function in young infants born with CDH.Methods:High resolution solid state manometry was used to investigate the esophageal function in 9 postoperative infants born with CDH (6 M, median age 23 days). A total of 416 liquid swallows were analyzed (range 27–70 swallows per patient; mean 46 swallows). All data are presented as median (IQR).Results:We included 9 patients: 8 with a left diaphragmatic defect, 5 with a “liver up” defect, 4 underwent a fetal tracheal occlusion procedure because of severe lung hypoplasia, 8 needed a patch to close a large diaphragmatic defect. Across patients, length of peristaltic defects was 0.4 (0.3,0.6) cm. Distal contractile integral (DCI) was 357 (249,428) mmHg.sec.cm. Distal Latency (DL) was 4.9 (3.6,5.6) sec, whereby 5/9 patients had a DL less than 4.5 sec. EGJ resting pressure was 37 (17,60) mmHg. The integrated relaxation pressure (IRP4) was 14 (9,19) mmHg with IRP4 over 15 mmHg in 4 patients.Conclusion:We investigated the esophageal body and EGJ function in 9 patients with CDH using high resolution manometry. This pilot study shows that the distal contractile integral is reduced in all infants with CDH. This reflects weak esophageal contractile strength and supports the congenital foregut dysmotility hypothesis. Surprisingly, deglutitive relaxation pressures were increased in only 4/9 patients suggesting that EGJ outflow obstruction post hernia repair of the crural diaphragm, is only partially contributing to the esophageal motor dysfunction observed in patients with CDH.

The effect of position on esophageal structure and function determined with solid-state high-resolution manometry.

To investigate the influence of posture on the anatomy and function of esophageal sphincters using solid-state high-resolution manometry. Fifty individuals underwent esophageal manometry with a 36-channel solid-state catheter in the supine and upright positions. The length and pressure of the esophageal sphincters, as well as the esophageal and intra-abdominal lengths of lower esophageal sphincter (LES), were recorded. The residual pressure of the upper esophageal sphincter (UES) and the 4-s integrated relaxation pressure were also measured when the participants swallowed 10 consecutive servings of water (5 mL each). The Bland-Altman plot was used to assess agreement between these parameters in the supine and upright positions. The LES resting pressure was significantly decreased in the upright position compared with the supine position (13.85 ± 5.90 mmHg vs 18.09 ± 7.80 mmHg, P = 0.000). Weaker integrated relaxation pressures were observed when the participants were in the upright position (5.66 ± 3.33 mmHg vs 7.80 ± 3.25 mmHg, P = 0.000). Compared with the supine position, the upright esophageal length was longer (P = 0.004) and the upper border of the LES was lower (P = 0.050) when the individuals were in the upright position. The agreement between the two positions was acceptable for the esophageal length, LES upper border location and LES pressure measurements. Body position exerts a greater influence on the LES than on the UES. Thus, it is necessary to establish normal values for the LES basal pressure and residual pressure in different positions.

PWE-246 Heterogeneity in manometry testing in the UK and around the world: Abstract PWE-246 Table 1

<h3>Introduction</h3> Oesophageal physiology testing has advanced markedly in the last decade. Tools such as high resolution manometry (HRM) have become widely available and have enhanced our understanding of oesophageal (dys)function. However this has also led to wide variation in testing methods and analysis. Before a consensus is built towards setting quality standards in physiological measurement, a better understanding of what procedures and practices actually take place globally is required. <h3>Method</h3> An on-line survey was distributed to oesophageal laboratories through NGM societies around the world using the internet-based Qualtrics platform. Questions explored infrastructure, staffing, technology, analysis and reporting. Labs responded anonymously. Responses from all labs were then compared. <h3>Results</h3> To date 41 responses have been received. Of the 17 in Britain/Ireland, 8 see 500–1000 referrals/year (3 &gt;1000) while 9 see &lt;500 cases/year. Both high volume (HV) and low volume (LV) centres employ a median of 7 members of staff; median 2.5 clinicians in HV and 1.0 in LV centres (p = 0.08). In comparison, of the 9 centres in USA, 6 in Europe and 9 in Australia, the overall median number of staff are 9, 7.5 and 5, of whom 4, 2 and 2 are clinicians respectively. In the Britain/Ireland, 7/17 centres use water-perfused and 10/17 use solid-state systems. 14 are high resolution of which 11 consist of at least 26 sensor systems (4 also with Impedance). In contrast, all labs in the USA and in Europe include a solid-state HRM systems with &gt;26 sensors and with Impedance, while in Australia 8/9 labs have &gt;26 sensor HRM systems, 5 of which include Impedance. Upright studies are routinely included in 5 centres in Britain/Ireland, 4 in USA, 3 in Europe and 4 in Australia. Details regarding adjunctive testing are presented in Table 1. In the UK, one HV and 2 LV centres never use the Chicago Classification (CC) to reach a diagnosis unlike all centres in Ireland, USA, Europe and Australia. Across all centres, placement of the lower oesophageal sphincter and gastric markers varies widely with varying sizes of hiatus hernia. Information provided in the final HRM report is fairly uniform apart from ‘therapeutic recommendations’ which is included in 4/17 centres in Britain/Ireland (3/8 HV and 1/9 LV centres), 3/9 in USA, 5/6 in Europe and 4/9 in Australia. <h3>Conclusion</h3> There is marked heterogeneity in the methodology, analysis and presentation of HRM studies in oesophageal laboratories around the world. This (ongoing) study sets the stage upon which mechanisms to improve quality and uniformity in testing and reporting can be agreed upon internationally. <h3>Disclosure of interest</h3> R. Sweis Grant/ Research Support from: Grant from Reckitt Benkiser, Conflict with: Invited as speaker for Given Imaging, M. Fox Consultant for: Member of advisory board and research/education funds from Given Imaging/Covidien, MMS and Sandhill.

Tu1424 Pressure Drift Correction in Prolonged Ambulatory Solid-State High-Resolution Manometry Systems

Tu1424 Pressure Drift Correction in Prolonged Ambulatory Solid-State High-Resolution Manometry Systems

Esophageal peristaltic defects in adults with functional dysphagia.

Functional dysphagia (FD) is characterized by the presence of dysphagia without evidence of mechanical esophageal obstruction, GERD, and histopathology-based esophageal motor disorders. Dysphagia is common in older patients; however, there is a paucity of information regarding the type and frequency of peristaltic abnormalities compared to younger patients. Based on recently validated criteria for classification of weak peristalsis using high-resolution manometry (HRM), we hypothesized that older patients with FD would have more peristaltic defects detected by HRM compared to younger FD patients. A retrospective review of our motility database yielded 65 patients that met inclusion criteria. Patients were divided into two groups based on age (younger: <70years; older: ≥70years). Patients were interviewed, completed a quality-of-life questionnaire, and underwent solid-state HRM. The two groups differed in age but in no other demographic characteristics, severity of dysphagia, or quality of life. Dyspeptic symptoms, including nausea (p<0.001), early satiety (p=0.01), bloating (p=0.02), and belching (p=0.01), were also more prevalent in younger FD patients. Older age was associated with weak peristalsis involving frequent failed peristalsis, small proximal peristaltic defects (2-5cm), and large proximal peristaltic defects (>5cm) (p<0.001). The mean contraction amplitude was also lower in the older group (p<0.05). These data support the hypothesis that older patients with FD have a higher frequency of peristaltic abnormalities on HRM compared to younger patients. Older age was associated with increased frequency of weak peristalsis with small and large peristaltic defects.

Mo1884 Inter-Rater and Inter-Device Agreement for the Diagnosis of Primary Esophageal Motility Disorders Based on Chicago Classification Between Solid-State and Water-Perfused HRM System -A Prospective, Randomized, Double Blind, Crossover Study

Background:High ResolutionManometry (HRM) is a new technique for intraluminal esophageal pressure measurement that employs an increased number of pressure sensors spaced closely together. Two systems have now become widely available: the 36 solid-state (SS) pressure transducers system, used to create the new Chicago Classification (CC) for Primary Esophageal Motility Disorders, and the recently introduced 24-channel water perfused (WP) system. Comparative data in terms of inter-device pressure parameters variability and diagnostic accuracy are lacking. Aim: To assess and compare normal values for pressure measurements between the 36-SS and the 24-WP HRM systems. Moreover, diagnostic inter-rater and inter-device agreement in a group of patients with esophageal symptoms were assessed. Methods: In this prospective, randomized, double blind, crossover study, 20 healthy volunteers [HVs; 11M/9F; median age 29 (IQR 26-33)] and 20 patients [11M/9F; 48 (43-55)] with esophageal symptoms (i.e. reflux symptoms, chest-pain or dysphagia) underwent HRM with both 36-SS (Given Imaging, Los Angeles, CA) and 24-WP (EB Neuro, Firenze, Italy) systems, in random order. Normal values from HVs were obtained and compared using non-parametric statistical analysis. Two expert reviewers (RS, ES) performed a blindfolded analysis of the patients tracings. Diagnoses based on CC in patients with esophageal symptoms were formulated. Inter-rater and inter-device agreement for each reviewer were evaluated by means of Cohen's k value. Results: As shown in the Figure, there were significant differences between the 2 HRM systems, mainly regarding the measurements of Lower Esophageal Sphincter (LES) and Upper Esophageal Sphincter (UES) basal pressure (p<0.01 and p=0.02, respectively), wave amplitude at 3 cm above the LES (p<0.01) and wave duration at 3, 7 and 11 cm above the LES (p<0.01, p<0.01 and p=0.01, respectively). Almost, all CC parameters were significantly different between the two HRM systems: Integrated Relaxation Pressure (IRP) (p=0.01), Distal Contractile Integral (DCI) (p=0.02) and Distal Latency (DL) (p<0.01). Diagnostic inter-rater agreement was higher for SS system (k=1) than for WP system (k=0,68). Diagnostic inter-device agreement was moderate for both reviewers (k[RS]= 0.5; k[ES]=0.4).Conclusions:Compared to the SS system, theWP technique underestimated almost all pressure measurements, including the CC parameters. This is likely due to the increased compliance of the WP system at low water perfusion rates, leading to poor interrater diagnosis reproducibility and inter-device agreement. By contrast, the SS system appears high reproducible in terms of inter-rater agreement. Thus, caution about the interpretation and application of CC in all HRM systems is recommended.

Water-perfused esophageal high-resolution manometry: normal values and validation

Water-perfused high-resolution manometry (HRM) catheters with 36 unidirectional pressure channels have recently been developed, but normal values are not yet available. Furthermore, the technique has not been validated and compared with solid-state HRM. We therefore aimed to develop normal values for water-perfused HRM and to assess the level of agreement between water-perfused HRM and solid-state HRM. We included 50 healthy volunteers (mean age 35 yr, range 21-64 yr; 15 women, 35 men). Water-perfused HRM and solid-state HRM were performed in a randomized order. Normal values were calculated as 5th and 95th percentile ranges, and agreement between the two systems was assessed with intraclass correlation coefficient (ICC) statistics. The 5th-95th percentile range was 3.0-6.6 cm/s for contractile front velocity (CFV), 141.6-3,674 mmHg·s·cm for distal contractile integral (DCI), 6.2-8.7 s for distal contraction latency (DL), and 1.0-18.8 mmHg for integrated relaxation pressure (IRP 4s). Mean (SD) and ICC for water-perfused HRM and solid-state HRM were 4.4 (1.1) vs. 3.9 (0.9) cm/s, ICC: 0.49 for CFV; 1,189 (1,023) vs. 1,092 (1,019) mmHg·s·cm, ICC: 0.90 for DCI; 7.4 (0.8) vs. 6.9 (0.9) s, ICC: 0.50 for DL; and 8.1 (4.8) vs. 7.9 (5.1), ICC: 0.39 for IRP 4s. The normal values for this water-perfused HRM system are only slightly different from previously published values with solid-state HRM, and moderate to good agreement was observed between the two systems, with only small differences in outcome measures.

Influence of the catheter diameter on the investigation of the esophageal motility through solid-state high-resolution manometry

Past studies have shown that catheter diameter is one of the device-dependent problems which influence the manometric results in the conventional water perfusion esophageal manometry. High-resolution solid-state manometry which abandons water perfusion is thought as an improved manometry method benefited from more pressure sensors, and it is gradually widely used in many present esophageal motility studies. There was no research to evaluate the influence of catheter diameter on the solid-state high-resolution manometry results. The aim of this study was to investigate whether solid-state high-resolution catheters of different diameter provide different data and results. Nine asymptomatic volunteers and 18 gastroesophageal reflux disease patients accepted high-resolution manometry examinations with two solid-state catheters of different outer diameter (4.2 mm and 2.7 mm). Every examination contained 5 minutes resting pressure, 10 water swallows and 10 bread swallows. Some important parameters of the esophageal sphincters and esophageal body peristalsis were analyzed. They included the locations and resting pressure of sphincters, the distal contractile integral, the 4-second integrated relaxation pressure etc. Then, these parameters and the diagnosis of each swallow based on them provided by the two different diameter catheters were compared. (i) The 4.2 mm thick catheter provided higher upper esophageal sphincter resting pressure than the 2.7 mm thick catheter (59.4 ± 21.1 mmHg vs. 49.7 ± 21.4 mmHg); (ii) the 2.7 mm thick catheter provided higher 4-second integrated relaxation pressure than the 4.2 mm thick catheter (10.9 ± 4.5 mmHg vs. 8.5 ± 3.8 mmHg) in water swallows; (iii) the mean distal contractile integral of the water and bread swallows in the large diameter catheter were higher than in the small diameter catheter (989.2 ± 650.0 mmHg/cm/s vs. 806.3 ± 563.7 mmHg/cm/s in water swallows, 1762.5 ± 1440.6 mmHg/cm/s vs. 1275.7 ± 982.0 mmHg/cm/s in bread swallows); (iv) on the lower esophageal sphincter resting pressure, most parameters in bread swallows provided by the two catheters were of no statistical significance; (v) the 2.7 mm thick catheter detected more hypotensive peristalsis swallows than the other catheter in water swallows; and (vi) the final diagnosis of about half of the subjects provided by the two catheters were different. The 2.7 mm thick solid-state high-resolution manometry catheter provides somewhat different data from the usually used 4.2 mm thick catheter. It is needed to set up different and independent series of normative value for the solid-state high-resolution manometry catheters of different outer diameter. The normative value and diagnostic criterion got from one catheter is not universal and acceptable for researches with catheter of different diameter.