Objective definition and detection of transient lower esophageal sphincter relaxation revisited: is there room for improvement?

Background The advent of drugs that inhibit transient lower esophageal sphincter relaxation (TLESR) necessitates accurate identification and scoring. We assessed the intra‐ and inter‐assessor variability of the existing objective criteria for TLESR, improving them where necessary. Methods Two 3‐h postprandial esophageal manometric and pH recordings were performed in 20 healthy volunteers. Each recording was duplicated. The recordings were analyzed by five experienced observers for TLESRs based on their expert opinion. TLESRs were also analyzed for the presence of the original four criteria as well as inhibition of the crural diaphragm (ID), a prominent after‐contraction (AC), acid reflux and an esophageal common cavity. Key Results The overall inter‐ and intra‐observer agreements for TLESRs scored, according to observer’s expert opinion, were 59% (range 56–67%) and 74% (60–89%), respectively. When TLESRs were restricted to those fulfilling the original criteria, these agreements fell to 46% (40–53%) and 60% (44–67%), respectively. Cleaning the recordings by removal of technically flawed sections improved agreements by 5%. Inclusion of additional criteria (ID and AC) resulted in inter‐ and intra‐observer agreements of 62% (52–70%) and 69% (53–79%), respectively. A consensus analysis performed collectively by three observers and based on the new criteria (original ± ID and AC) resulted in 84% agreement between the paired recordings. Conclusions & Inferences The original criteria for the definition of TLESRs allows for substantial inter‐ and intra‐observer variability, which can be reduced by incorporation of additional objective criteria. However, the highest level of intra‐observer agreement can be achieved by consensus analysis.     

Localizing the contractile deceleration point (CDP) in patients with abnormal esophageal pressure topography

Background The contractile deceleration point (CDP) is an important landmark for interpreting esophageal pressure topography (EPT) plots. Previous analysis in normal subjects confirmed that the CDP could be localized using an algorithm that found the time during peristalsis at which a maximal length of the distal esophagus was contracting concurrently (tML method). This study aimed to test the tML method for localizing CDP in patients with abnormal motility. Methods High‐resolution manometry studies of 75 patients with normal and disordered peristalsis were analyzed. Two experts, JEP and YX, used the original tangent‐intersection method to score CDP coordinates for the first two swallows of each study. Alternative computerized algorithms tested against the expert were: (i) the tML method, (ii & iii) the intercept between the leading edge of the 30‐mmHg isobaric contour and a line 2.0 cm (or 10% of esophageal length) proximal to the esophagogastric junction (EGJ) at rest, or (iv) the ‘tML‐3 cm’ method, which added the stipulation that the CDP be within 3 cm of the EGJ. Key Results All tested algorithms were highly correlated with the expert. However, the tMl‐3 cm method was better in the sense that it eliminated outliers (>1 s discrepancy with the expert) that occurred with the other methods usually attributable to weak distal peristalsis. Conclusions & Inferences Optimal automated CDP localization was achieved in both normal and a spectrum of abnormal motility using the tML method with the added stipulation that the CDP be restricted to within the distal 3 cm of the EGJ at rest.     

Refining the criterion for an abnormal Integrated Relaxation Pressure in esophageal pressure topography based on the pattern of esophageal contractility using a classification and regression tree model

Background The Integrated Relaxation Pressure (IRP) is the esophageal pressure topography (EPT) metric used for assessing the adequacy of esophagogastric junction (EGJ) relaxation in the Chicago Classification of motility disorders. However, because the IRP value is also influenced by distal esophageal contractility, we hypothesized that its normal limits should vary with different patterns of contractility. Methods Five hundred and twenty two selected EPT studies were used to compare the accuracy of alternative analysis paradigms to that of a motility expert (the ‘gold standard’). Chicago Classification metrics were scored manually and used as inputs for MATLAB? programs that utilized either strict algorithm‐based interpretation (fixed abnormal IRP threshold of 15 mmHg) or a classification and regression tree (CART) model that selected variable IRP thresholds depending on the associated esophageal contractility. Key Results The sensitivity of the CART model for achalasia (93%) was better than that of the algorithm‐based approach (85%) on account of using variable IRP thresholds that ranged from a low value of >10 mmHg to distinguish type I achalasia from absent peristalsis to a high value of >17 mmHg to distinguish type III achalasia from distal esophageal spasm. Additionally, type II achalasia was diagnosed solely by panesophageal pressurization without the IRP entering the algorithm. Conclusions & Inferences Automated interpretation of EPT studies more closely mimics that of a motility expert when IRP thresholds for impaired EGJ relaxation are adjusted depending on the pattern of associated esophageal contractility. The range of IRP cutoffs suggested by the CART model ranged from 10 to 17 mmHg.     

Assessment of esophageal function in patients with myasthenia gravis

Background: Myasthenia gravis (MG) is an autoimmune disease in which impairment of neuromuscular transmission results in a pathological fatigability of striated muscles. Dysphagia is a common symptom in MG. It is caused by a weakness of the striated muscles in the pharynx and esophagus. The purpose of our study was to evaluate the role of esophageal scintigraphy in the assessment of esophageal function in MG. Methods: In 15 patients with clinically proven MG (oculopharyngeal manifestation in 6/15 patients, generalized weakness in 9/15 patients) esophageal transit was investigated scintigraphically with a multiple swallow test protocol. 10/15 patients had a history of dysphagia. Patients were studied twice: under baseline conditions, and immediately after pharmacological stimulation with 10 mg of edrophonium chloride (EC), a short-acting acetylcholinesterase inhibitor. Results: Under baseline conditions all patients showed an impaired esophageal function (emptying [%]= 58 % ± 21; normal range > 85 %). In 14/15 individuals esophageal transit improved after administration of EC (emptying [%]= 75 % ± 18; p < 0.01), reaching the normal range in 6 patients. One patient showed no effect attributable to EC. Conclusions: Esophageal transit is often compromised in MG. Functional abnormalities may be also present in patients without a history of dysphagia. Inhibition of cholinesterase positively affects striated muscles in the pharynx and upper esophagus, thus improving esophageal transit. Esophageal scintigraphy may be considered as a simple, non-invasive method for diagnosing impairment of esophageal function in MG and to monitor the changes under pharmacological stimulation. Received: 20 August 2002, Received in revised form: 11 December 2002, Accepted: 18 December 2002 Correspondence to Rainer Linke, MD     

Diagnosis of supra‐esophageal gastric reflux: correlation of oropharyngeal pH with esophageal impedance monitoring for gastro‐esophageal reflux

Background Oropharyngeal (OP) pH monitoring has been developed as a new way to diagnose supra‐esophageal gastric reflux (SEGR), but has not been well validated. Our aim was to determine the correlation between OP pH and gastro‐esophageal reflux (GER) events detected by multichannel intraluminal impedance‐pH (MII‐pH). Methods Fifteen patients (11 males, median age 10.8 years) with suspected GER were prospectively evaluated with ambulatory 24‐h OP pH monitoring (positioned at the level of the uvula) and concomitant esophageal MII‐pH monitoring. Potential OP events were identified by the conventional pH threshold of <4 and by the following alternative criteria: (i) relative pH drop >10% from 15‐min baseline and (ii) absolute pH drop below thresholds of <5.5, 5.0, and 4.5. The 2‐min window preceding each OP event was analyzed for correlation with an episode of GER detected by MII‐pH. Key Results A total of 926 GER events were detected by MII‐pH. Application of alternative pH criteria increased the identification of potential OP pH events; however, a higher proportion of OP events had no temporal correlation with GER (45–81%), compared with the conventional definition of pH < 4 (40%). A total of 306 full‐column acid reflux episodes were detected by MII‐pH, of which 10 (3.3%) were also identified by OP pH monitoring. Conclusions & Inferences Use of extended pH criteria increased the detection of potential SEGR events, but the majority of decreases in OP pH were not temporally correlated with GER. Oropharyngeal pH monitoring without concurrent esophageal measurements may overestimate the presence of SEGR in children.     

High‐resolution esophageal pressure topography is superior to conventional sleeve manometry for the detection of transient lower esophageal sphincter relaxations associated with a reflux event

Background Transient lower esophageal sphincter relaxations (TLESRs) are the main mechanism underlying gastro‐esophageal reflux and are detected during manometric studies using well defined criteria. Recently, high‐resolution esophageal pressure topography (HREPT) has been introduced and is now considered as the new standard to study esophageal and lower esophageal sphincter (LES) function. In this study we performed a head‐to‐head comparison between HREPT and conventional sleeve manometry for the detection of TLESRs. Methods A setup with two synchronized MMS‐solar systems was used. A solid state HREPT catheter, a water‐perfused sleeve catheter, and a multi intraluminal impedance pH (MII‐pH) catheter were introduced in 10 healthy volunteers (M6F4, age 19–56). Subjects were studied 0.5 h before and 3 h after ingestion of a standardized meal. Tracings were blinded and analyzed by the three authors according to the TLESR criteria. Key Results In the HREPT mode 156 TLESRs were scored, vs 143 during sleeve manometry (P = 0.10). Hundred and twenty‐three TLESRs were scored by both techniques. Of all TLESRs (177), 138 were associated with reflux (78%). High‐resolution esophageal pressure topography detected significantly more TLESRs associated with a reflux event (132 vs 119, P = 0.015) resulting in a sensitivity for detection of TLESRs with reflux of 96% compared to 86% respectively. Analysis of the discordant TLESRs associated with reflux showed that TLESRs were missed by sleeve manometry due to low basal LES pressure (N = 5), unstable pharyngeal signal (N = 4), and residual sleeve pressure >2 mmHg (N = 10). Conclusions & Inferences The HREPT is superior to sleeve manometry for the detection of TLESRs associated with reflux. However, rigid HREPT criteria are awaited.     

3D‐high resolution manometry of the esophagogastric junction

Background The esophagogastric junction (EGJ) is a complex structure that challenges accurate manometric recording. This study aimed to define EGJ pressure morphology relative to the squamocolumnar junction (SCJ) during respiration with 3D‐high resolution manometry (3D‐HRM). Methods A 7.5‐cm long 3D‐HRM array with 96 independent solid‐state pressure sensors (axial spacing 0.75 cm, radial spacing 45°) was used to record EGJ pressure in 15 normal subjects. Concurrent videofluoroscopy was used to localize the SCJ marked with an endoclip. Ex vivo experiments were done on the effect of bending the probe to match that seen fluoroscopically. Key Results 3D‐high resolution manometry EGJ pressure recordings were dominated by an asymmetric pressure peak superimposed on the lower esophageal sphincter (LES) attributable to the crural diaphragm (CD). Median peak CD pressure at expiration and inspiration (51 and 119 mmHg, respectively) was much greater in 3D‐HRM than evident in HRM with circumferential pressure averaging. Esophagogastric junction length, defined as the zone of circumferential pressure exceeding that of adjacent esophagus or stomach was also substantially shorter (2.4 cm) than evident in conventional HRM. No consistent circumferential EGJ pressure was evident distal to the SCJ in 3D‐HRM recordings and ex vivo experiments suggested that the intra‐gastric pressure peak seen contralateral to the CD related to bending the assembly rather than the sphincter per se. Conclusions & Inferences 3D‐high resolution manometry demonstrated a profoundly asymmetric and vigorous CD component to EGJ pressure superimposed on the LES. Esophagogastric junction length was shorter than evident with conventional HRM and the distal margin of the EGJ sphincteric zone closely correlated with the SCJ.