Optimal number of multiple rapid swallows needed during high-resolution esophageal manometry for accurate prediction of contraction reserve

Esophageal motor abnormalities in gastroesophageal reflux disorders

Gastroesophageal reflux disease (GERD), a prevalent condition with multifactorial pathogenesis, involves esophageal motor dysmotility as a key contributing factor to its development. When suspected GERD patients have an inadequate response to proton-pump inhibitor (PPI) therapy and normal upper endoscopy results, high-resolution manometry (HRM) is utilized to rule out alternative diagnosis such as achalasia spectrum disorders, rumination, or supragastric belching. At present, HRM continues to provide supportive evidence for diagnosing GERD and determining the appropriate treatment. This review focuses on the existing understanding of the connection between esophageal motor findings and the pathogenesis of GERD, along with the significance of esophageal HRM in managing GERD patients. The International GERD Consensus Working Group introduced a three-step method, assessing the esophagogastric junction (EGJ), esophageal body motility, and contraction reserve with multiple rapid swallow (MRS) maneuvers. Crucial HRM abnormalities in GERD include frequent transient lower esophageal sphincter relaxations, disrupted EGJ, and esophageal body hypomotility. Emerging HRM metrics like EGJ-contractile integral and innovative provocative maneuver like straight leg raise have the potential to enhance our understanding of factors contributing to GERD, thereby increasing the value of HRM performed in patients who experience symptoms suspected of GERD.

Esophageal motility disorder - has Chicago classification v4.0 simplified our management?

REVIEW PURPOSE

Addressing dysphagia is vital due to its prevalence and impact on healthcare expenditure. While high resolution manometry (HRM) effectively evaluates esophageal dysphagia, its role in oropharyngeal dysphagia and upper esophageal sphincter (UES) dysfunction remains debated. The fourth iteration of the Chicago classification (CC) offers an algorithmic approach for diagnosing abnormal motor patterns via HRM. This review assesses the CC's impact on dysphagia management.

RECENT INSIGHTS

The Chicago classification version 4.0 emphasizes auxiliary and provocative techniques when the algorithm falls short of a conclusive diagnosis. It introduces stricter criteria for previously ambiguous conditions like ineffective motility and esophagogastric junction outflow obstruction. This version also introduces the concept of conclusive and inconclusive classifications based on symptoms, provocation maneuvers, and supportive testing minimizing ambiguity.

SUMMARY

The Chicago classification v4.0 remains a useful tool for the diagnosis of well characterized esophageal motility disorders. However, major limitations include reliance on HRM and a focus on distal esophagus contractile characteristics without considering proximal esophagus or upper esophageal sphincter, both of which can sometimes be the only evident abnormality in patients with dysphagia. Despite efforts to reduce ambiguity, diagnostic challenges persist. These limitations can be addressed in future updates.

Effect of inter-swallow interval on striated esophagus peristalsis; a comparative study with smooth muscle esophagus

BACKGROUND

Effect of inter-swallow interval on the contractility of smooth muscle esophagus is well-documented. However, the effects on peristalsis of the striated esophagus have not been systematically studied. A better understanding of striated esophagus motor function in health and disease may enhance the interpretation of manometric studies and inform clinical care. The aim of this study was to assess the effect of inter-swallow interval on striated esophagus compared to findings with that of the smooth muscle esophagus.

METHODS

We performed two sets of studies to (1) determine the effect of various inter-swallow interval in 20 healthy volunteers and (2) assess the effect of ultra-short swallow intervals facilitated by straw drinking in 28 volunteers. We analyzed variables using ANOVA with Tukey's pairwise comparison and paired t-test.

KEY RESULTS

Unlike smooth muscle esophagus, the striated esophagus contractile integral did not change significantly for swallow intervals ranging from 30 to 5 s. On the contrary, striated esophagus demonstrated absent or reduced peristalsis in response to ultra-short (<2 s) intervals during straw-facilitated multiple rapid swallows.

CONCLUSIONS AND INFERENCES

Striated esophagus peristalsis is subject to manometrically observed inhibition during swallows with ultra-short intervals. Inter-swallow intervals as short as 5 s that inhibit smooth muscle esophagus peristalsis do not inhibit striated muscle peristalsis. The mechanisms of these observations are unknown but may relate to central or myenteric nervous system influences or the effects of pharyngeal biomechanics.

A Short History of High-Resolution Esophageal Manometry

High-resolution esophageal manometry (HRM) utilizes sufficient pressure sensors such that intraluminal pressure is monitored as a continuum along luminal length, similar to time viewed as a continuum on polygraph tracings in 'conventional' manometry. When HRM is coupled with pressure topography plotting, and pressure amplitude is transformed into spectral colors with isobaric areas indicated by same-colored regions, "Clouse plots" are generated. HRM has several advantages compared to the technology that it replaced: (1) the contractility of the entire esophagus can be viewed simultaneously in a uniform standardized format, (2) standardized objective metrics of peristaltic and sphincter function can be systematically applied for interpretation, and (3) topographic patterns of contractility are more easily recognized with greater reproducibility. Leveraging these advantages led to the current standard for the interpretation of clinical esophageal HRM studies, the Chicago Classification (CC), now in its fourth iteration. Compared to conventional manometry, HRM has vastly improved the sensitivity for detecting achalasia, largely due to the objectivity and accuracy of identification of impaired esophagogastric junction (EGJ) relaxation. Additionally, it has led to the subcategorization of achalasia into three clinically relevant subtypes, differentiated by the contractile function of the esophageal body, and identified an additional disorder of EGJ outflow obstruction wherein esophageal peristalsis is preserved. Headway has also been made in understanding hypocontractile and hypercontractile conditions. In summary, HRM and the CC process have revolutionized our understanding of esophageal motility and motility disorders. Moving forward, there will always be remaining challenges, but we now have the tools to meet them.

Concise Review: Applicability of High-resolution Manometry in Gastroesophageal Reflux Disease

Manometry, particularly high-resolution manometry is the preferred diagnostic tool used to evaluate esophageal motor function. This investigation is strongly indicated in the setting of dysphagia, but is also useful in gastroesophageal reflux disease (GERD), especially in case of failure of conventional treatment to exclude alternative diagnoses and prior to anti-reflux surgery. Moreover, ineffective esophagogastric junction barrier function and esophageal motor dysfunction are pathophysiological mechanisms in GERD and can be identified by manometry. The recent international guidelines have positioned high-resolution manometry as an important part of functional diagnostic work up in GERD in order to identify the GERD phenotype to guide specific treatment. The proposed manometric identification and measurement is based on the Chicago classification version 4.0 adding with new established metrics for GERD evaluation.

How provocative tests in addition to wet swallows during high-resolution manometry can direct clinical management

PURPOSE OF REVIEW

Provocative tests have been advocated to address limitations of high-resolution manometry (HRM) with wet swallows. We describe the commonly used provocative manometric manoeuvres [rapid drink challenge (RDC), multiple rapid swallows (MRS), solid swallows and the solid test meal (STM)], compare their diagnostic yield and accuracy to wet swallows, and outline their role in directing clinical management.

RECENT FINDINGS

Provocative testing with RDC and STM identifies a proportion of achalasia cases missed by standard testing, and RDC can play a similar role to radiology in the evaluation of treatment response. In EGJOO, provocative testing with RDC and STM not only increase the diagnostic yield, but can also help differentiate between spurious cases and those representing true outflow obstruction likely to respond to achalasia-type therapies. MRS and STM can help determine the clinical relevance (or otherwise) of ineffective oesophageal motility, and in this setting, MRS may predict the likelihood of postfundoplication dysphagia. RDC and STM can help identify cases of postfundoplication dysphagia more likely to respond to dilatation.

SUMMARY

Provocative testing has been shown to increase diagnostic yield of HRM, clarify inconclusive diagnoses, allows corroboration of dysmotility with patient symptoms and helps direct clinical management.

Advancing high-resolution manometry: evaluating the use of multiple rapid swallows versus apple viscous swallows in clinical practice

BACKGROUND

High-Resolution Manometry (HRM) with provocative maneuvers, such as Multiple Rapid Swallows (MRS) and Apple Viscous Swallows (AVS), is commonly utilized to diagnose esophageal disorders. Increasing standardization in HRM protocol can help save time and reduce patient discomfort. This study assesses AVS and MRS to determine their respective benefits and limitations.

METHODS

Retrospective reviews were performed on 100 patients to analyze their AVS and/or MRS results. Parameters included abnormal motility patterns, tolerance, and DCI. Diagnostic benefits from MRS and AVS were assessed. Based on the previous studies, additional benefit from MRS was defined as detection of good peristaltic reserve, weak peristaltic reserve, or an abnormal motility/pressurization pattern. Additional benefit from AVS was defined as detection of IEM features or abnormal motility/pressurization pattern.

RESULTS

When patients completed both MRS and AVS (n = 70), MRS provided additional benefit in assessing 36% of patients, while AVS provided additional benefit in 19% of patients (p < 0.0001). Furthermore, MRS detected significantly more abnormal motility/pressurization patterns than AVS (27% MRS; 8% AVS; p = 0.0005). Two unique strengths of AVS were higher tolerance for test completion (p = 0.009) and better detection of severe hypokinetic disorders in 4% of patients, which were missed by MRS.

CONCLUSIONS

MRS may uniquely identify abnormal motility/pressurization patterns, such as paradoxical LES response, distal pressurization, hypercontractile, and spasm patterns. These findings argue for a tailored approach when selecting provocative testing. MRS may be more useful for patients with abnormal pathophysiology, while AVS may help to supplement MRS in detecting severe hypokinetic disorders in preoperative management.

Esophageal Motility Disorders: Current Approach to Diagnostics and Therapeutics

Dysphagia is a common symptom with significant impact on quality of life. Our diagnostic armamentarium was primarily limited to endoscopy and barium esophagram until the advent of manometric techniques in the 1970s, which provided the first reliable tool for assessment of esophageal motor function. Since that time, significant advances have been made over the last 3 decades in our understanding of various esophageal motility disorders due to improvement in diagnostics with high-resolution esophageal manometry. High-resolution esophageal manometry has improved the sensitivity for detecting achalasia and has also enhanced our understanding of spastic and hypomotility disorders of the esophageal body. In this review, we discuss the current approach to diagnosis and therapeutics of various esophageal motility disorders.

Clinical usefulness of esophageal high resolution manometry and adjunctive tests: An update

High resolution manometry (HRM), developed from conventional manometry, is the gold standard for assessment of esophageal motor function worldwide. The Chicago Classification, now in its fourth iteration, is the modern standard for HRM categorization of esophageal motility disorders. The HRM protocol has expanded from the original 10 supine swallow standard, to include upright swallows, and provocative maneuvers such as multiple rapid swallows, rapid drink challenge and standardized test meal. Impedance has been incorporated into HRM for visualization of bolus clearance. Futhermore, barium radiography and functional lumen imaging probe complement HRM when evidence of esophagogastric junction obstruction is inconclusive. The biggest impact of HRM is in the improved diagnosis and subtyping of achalasia spectrum disorders, with implications on management. Spastic disorders and absent contractility are better characterized. Within the reflux spectrum, HRM provides definition of morphology and tone of the esophagogastric junction, and assesses integrity of esophageal body peristalsis, which have pathophysiologic implications for reflux and its clearance. HRM provides characterization of behavioral disorders such as supragastric belching and rumination syndrome, which can mimic reflux disease. Thus, HRM has revolutionized the evaluation of esophageal motor function, and has expanded the utility of esophageal manometry in clinical practice.

Chicago Classification update (V4.0): Technical review on diagnostic criteria for ineffective esophageal motility and absent contractility

Esophageal hypomotility disorders manifest with abnormal esophageal body contraction vigor, breaks in peristaltic integrity, or failure of peristalsis in the context of normal lower esophageal sphincter relaxation on esophageal high-resolution manometry (HRM). The Chicago Classification version 4.0 recognizes two hypomotility disorders, ineffective esophageal motility (IEM) and absent contractility, while fragmented peristalsis has been incorporated into the IEM definition. Updated criteria for ineffective swallows consist of weak esophageal body contraction vigor measured using distal contractile integral (DCI, 100-450 mmHg·cm·s), transition zone defects >5 cm measured using a 20 mmHg isobaric contour, or failure of peristalsis (DCI < 100 mmHg·cm·s). More than 70% ineffective swallows and/or ≥50% failed swallows are required for a conclusive diagnosis of IEM. When the diagnosis is inconclusive (50%-70% ineffective swallows), supplementary evidence from multiple rapid swallows (absence of contraction reserve), barium radiography (abnormal bolus clearance), or HRM with impedance (abnormal bolus clearance) could support a diagnosis of IEM. Absent contractility requires 100% failed peristalsis, consistent with previous versions of the classification. Consideration needs to be given for the possibility of achalasia in absent contractility with dysphagia despite normal IRP, and alternate complementary tests (including timed upright barium esophagram and functional lumen imaging probe) are recommended to confirm or refute the presence of achalasia. Future research to quantify esophageal bolus retention on stationary HRM with impedance and to understand contraction vigor thresholds that predict bolus clearance will provide further refinement to diagnostic criteria for esophageal hypomotility disorders in future iterations of the Chicago Classification.

Variations in Clinical Practice of Esophageal High-resolution Manometry: A Nationwide Survey

Background/Aims

Esophageal high-resolution manometry (HRM) enables the comprehensive evaluation of the esophageal motor function. However, protocols are not uniform and clinical practices vary widely among institutions. This study aims to understand the current HRM practice in Korea.

Methods

The survey was sent via email through the Korean Society of Neurogastroenterology and Motility. The questions covered descriptive information, preparation, techniques, analysis, and reporting of esophageal HRM.

Results

The survey was completed in 32 (74.4%) out of 43 centers, including 24 tertiary and 8 secondary referral centers. Of the 32 centers, 25 (78.1%) performed HRM in a sitting position, while 7 centers (21.9%) reported performing HRM in a supine position. All the centers utilized single wet swallows as a standard, but the volume, frequency, and interval between swallows varied widely. Sixteen centers (50.0%) applied adjunctive tests, including multiple rapid swallows (n = 16) and rapid drink challenges (n = 9). Parameters assessed and documented in the report were similar. In addition to the assessment of the esophagogastric junction and esophageal body, 27 centers (84.8%) and 18 centers (56.3%) included measurements for the upper esophageal sphincter and the pharynx, respectively, in the HRM protocol.

Conclusions

We found a variation in the available HRM practice among centers, even though they broadly agreed in the data analysis. Efforts are needed to develop a standardized protocol for HRM measurement.

Chicago Classification Update (v4.0): Technical review on diagnostic criteria for hypercontractile esophagus

Hypercontractile esophagus (HE), defined by the Chicago Classification version 3.0 (CCv3.0) as 20% or more hypercontractile peristalsis (Distal Contractile Integral >8000 mmHg·s·cm) on high-resolution manometry (HRM), is a heterogeneous disorder with variable clinical presentations and natural course, leading to management challenges. An update on the diagnostic criteria for clinically relevant HE was needed. Literature on HE was extensively reviewed by the HE subgroup of the Chicago Classification version 4.0 (CCv4.0) Working Group and statements relating to the diagnosis of HE were ranked according to the RAND UCLA Appropriateness methodology by the Working Group, and the quality of evidence was rated using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework. An overall emphasis of the CCv4.0 is on clinically relevant esophageal dysmotility, and thus it is recommended that an HE diagnosis requires both conclusive manometric diagnosis and clinically relevant symptoms of dysphagia and non-cardiac chest pain. The Working Group also recognized the subtypes of HE, including single-peaked, multi-peaked contractions (Jackhammer esophagus), and hypercontractile lower esophageal sphincter. However, there are no compelling data currently for formally subdividing HE to these subgroups in clinical practice.

European Society for Neurogastroenterology and Motility (ESNM) recommendations for the use of high-resolution manometry of the esophagus

BACKGROUND

Several patients in gastroenterology practice present with esophageal symptoms, and in case of normal endoscopy with biopsies, high-resolution manometry (HRM) is often the next step. Our aim was to develop a European consensus on the clinical application of esophageal HRM, to offer the clinician guidance in selecting patients for HRM and using its results to optimize clinical outcome.

METHODS

A Delphi consensus was initiated with 38 multidisciplinary experts from 16 European countries who conducted a literature summary and voting process on 71 statements. Quality of evidence was evaluated using grading of recommendations assessment, development, and evaluation (GRADE) criteria. Consensus (defined as >80% agreement) was reached for 33 statements.

RESULTS

The process generated guidance on when to consider esophageal HRM, how to perform it, and how to generate the report. The Delphi process also identified several areas of uncertainty, such as the choice of catheters, the duration of fasting and the position in which HRM is performed, but recommended to perform at least 10 5-ml swallows in supine position for each study. Postprandial combined HRM impedance is considered useful for diagnosing rumination. There is a large lack of consensus on treatment implications of HRM findings, which is probably the single area requiring future targeted research.

CONCLUSIONS AND INFERENCES

A multinational and multidisciplinary group of European experts summarized the current state of consensus on technical aspects, indications, performance, analysis, diagnosis, and therapeutic implications of esophageal HRM.

Chicago classification version 4.0© technical review: Update on standard high-resolution manometry protocol for the assessment of esophageal motility

The Chicago Classification v4.0 (CCv4.0) is the updated classification scheme for esophageal motility disorders using metrics from high-resolution manometry (HRM). A key feature of CCv.4.0 is the more rigorous and expansive protocol that incorporates single wet swallows acquired in different positions (supine, upright) and provocative testing, including multiple rapid swallows and rapid drink challenge. Additionally, solid bolus swallows, solid test meal, and/or pharmacologic provocation can be used to identify clinically relevant motility disorders and other conditions (eg, rumination) that occur during and after meals. The acquisition and analysis for performing these tests and the evidence supporting their inclusion in the Chicago Classification protocol is detailed in this technical review. Provocative tests are designed to increase the diagnostic sensitivity and specificity of HRM studies for disorders of esophageal motility. These changes attempt to minimize ambiguity in prior iterations of Chicago Classification, decrease the proportion of HRM studies that deliver inconclusive diagnoses and increase the number of patients with a clinically relevant diagnosis that can direct effective therapy. Another aim in establishing a standard manometry protocol for motility laboratories around the world is to facilitate procedural consistency, improve diagnostic reliability, and promote collaborative research.

Evaluation of esophageal motor function in patients with gastroesophageal reflux using multiple rapid swallows

Multiple rapid swallow (MRS) is a complementary test performed during high-resolution esophageal manometry (HREM). The present study was done to assess the MRS findings in patients with gastroesophageal reflux disease (GERD) who have normal peristalsis and minor motility disorders. This is a retrospective analysis from a prospectively maintained database of patients referred for HREM study to our center. The recorded details included age, sex, symptoms with duration, and upper gastrointestinal endoscopy reports. HREM data included basal inspiratory and expiratory pressures, median integrated relaxation pressure, and peristaltic pattern. Three MRS sequences were recorded per patient. The inhibition and contraction phases were interpreted for each MRS sequence. A total of 68 patients (38 normal motility, 30 minor motility disorders) formed the study cohort. Hiatus hernia was common in GERD patients with minor motility disorders (p 0.02). Patients with minor motility disorders were more likely to have poor peristaltic reserve than patients with normal peristalsis (p < 0.05). MRS patterns in inhibition and contraction phases were similar in the three MRS sequences for patients with normal peristalsis, while in patients with minor peristaltic disorders, the inhibition phase was significantly discordant on repetitive MRS (p 0.049). Thus, in GERD patients, those with normal peristalsis were more likely to have normal MRS pattern. On the contrary, those with minor peristaltic disorders had a higher frequency of poor peristaltic reserve and show significant discordance in the inhibition phase of MRS.

Application of a novel straight leg raise test during high-resolution manometry can predict esophageal contractile reserve in patients with gastroesophageal reflux disease

BACKGROUND/AIM

Increased intra-abdominal pressure from abdominal compression augments esophageal peristalsis during high-resolution manometry (HRM), and straight leg raise (SLR) while supine increases intra-abdominal pressure. We determined if water swallows performed during SLR can mimic contraction reserve seen with multiple rapid swallows (MRS).

METHODS

Consecutive patients evaluated for GERD symptoms completed validated GERD questionnaires, esophageal HRM, and upper endoscopy. Distal contractile integral (DCI) was analyzed during single water swallows (10 × 5 mL), MRS (5 × 2 mL), and during SLR (5x5 mL). Peristaltic breaks were measured using software tools with a 20 mm Hg isobaric contour. Univariate correlational analyses were performed to compare esophageal motor patterns and DCI values during single water swallows, MRS, and SLR.

RESULTS

Of 103 study patients (mean age: 46.7 ± 12.3 years, 56.3% female), 50 (48.5%) had ineffective esophageal motility (IEM). Contraction reserve was observed on MRS in 62% with IEM, and 35.8% with normal motility (p = 0.008). DCI was significantly higher during SLR compared to mean single swallow DCI in both IEM and normal motility patients (p < 0.001 for each comparison). In IEM patients, SLR significantly reduced swallows with peristaltic breaks (6.1 ± 3.7 vs 3.6 ± 3.6; p < 0.001) and shortened the length of the largest break (4.8 ± 3.4 vs 3.0 ± 3.0 cm; p < 0.001). DCI response following MRS correlated with DCI with swallows during SLR, with a correlational coefficient (Pearson's r) of 0.70 (p < 0.001).

CONCLUSIONS

Swallowing against the resistance of increased intra-abdominal pressure from SLR improves esophageal body peristaltic performance and predicts esophageal body contraction reserve.

Assessment of the Multiple Rapid Swallows Test for Gauging Esophageal Reflux Burden in Patients with Refractory Gastroesophageal Reflux Disease

BACKGROUND The multiple rapid swallows (MRS) test is used to assess esophageal contraction reserve. In this study, we characterized the expression of the MRS test in patients with reflux burden and other symptomatic phenotypes with refractory gastroesophageal reflux disease (rGERD). MATERIAL AND METHODS Patients with rGERD who underwent high-resolution manometry (HRM) and esophageal pH-impedance monitoring (EIM) between September 2018 and January 2020 were retrospectively studied. RESULTS We enrolled 151 patients and divided them into 4 phenotypes according to the results of EIM. In phenotype 1, the MRS distal contractile integral (DCI) was significantly positively correlated with acid-liquid reflux episodes. In phenotype 2, lower esophageal sphincter pressure (LES) length was significantly positively correlated with MRS DCI, and MRS/single-swallow (SS) DCI ratio. In phenotype 3, MRS DCI was negatively correlated with the DeMeester score, acid exposure time (AET), upright AET, long-term acid reflux episodes, acid-mixed reflux episodes, recumbent acid reflux episodes, and total acid reflux episodes. There was a significant negative correlation between MRS/SS DCI and recumbent acid reflux episodes. In phenotype 4, nonacid-liquid episodes and recumbent nonacid reflux episodes were significantly higher in the abnormal MRS group. However, acid-gas episodes, weakly acid-gas episodes, and upright gas reflux episodes were higher in the normal MRS group than in the abnormal MRS group. CONCLUSIONS Esophageal contraction reserve is heterogeneous within the reflux burden and symptomatic phenotypes of patients with rGERD.

The Clinical Utility of Provocative Maneuvers at Esophageal High-resolution Manometry (HRM)

Esophageal high-resolution manometry (HRM) assesses esophageal motor function and is indicated both for evaluation of esophageal symptoms and before antireflux interventions. HRM studies are interpreted and esophageal motor diagnoses made according to the Chicago Classification, version 3.0 algorithm, which is based on ten 5 mL supine water swallows. However, this practice of single liquid swallows performed in the supine position does not reflect typical "real-life" swallowing, and may not reproduce the patient's presenting symptoms. Therefore, provocative maneuvers at HRM-beyond these 10 standard swallows-can afford additional insights into esophageal motor function with clinically significant implications, and represent areas of exciting investigation and innovation. Accordingly, the 2020 American College of Gastroenterology Guidelines on Esophageal Physiologic Testing conditionally recommend their inclusion in the HRM protocol. In this clinical review, we discuss the supporting data for and clinical utility of provocative maneuvers at HRM that include changes in body position or accessories (upright swallows, "bridge" position, straight leg raise, abdominal compression), bolus consistency (solid swallows, test meals, postprandial high-resolution impedance manometry), bolus frequency (multiple rapid swallows), the volume of bolus (rapid drink challenge/multiple water swallows), and the use of pharmacological agents.

Hypercontractile Esophagus From Pathophysiology to Management: Proceedings of the Pisa Symposium

Hypercontractile esophagus (HE) is a heterogeneous major motility disorder diagnosed when ≥20% hypercontractile peristaltic sequences (distal contractile integral >8,000 mm Hg*s*cm) are present within the context of normal lower esophageal sphincter (LES) relaxation (integrated relaxation pressure < upper limit of normal) on esophageal high-resolution manometry (HRM). HE can manifest with dysphagia and chest pain, with unclear mechanisms of symptom generation. The pathophysiology of HE may entail an excessive cholinergic drive with temporal asynchrony of circular and longitudinal muscle contractions; provocative testing during HRM has also demonstrated abnormal inhibition. Hypercontractility can be limited to the esophageal body or can include the LES; rarely, the process is limited to the LES. Hypercontractility can sometimes be associated with esophagogastric junction (EGJ) outflow obstruction and increased muscle thickness. Provocative tests during HRM can increase detection of HE, reproduce symptoms, and predict delayed esophageal emptying. Regarding therapy, an empiric trial of a proton pump inhibitor, should be first considered, given the overlap with gastroesophageal reflux disease. Calcium channel blockers, nitrates, and phosphodiesterase inhibitors have been used to reduce contraction vigor but with suboptimal symptomatic response. Endoscopic treatment with botulinum toxin injection or pneumatic dilation is associated with variable response. Per-oral endoscopic myotomy may be superior to laparoscopic Heller myotomy in relieving dysphagia, but available data are scant. The presence of EGJ outflow obstruction in HE discriminates a subset of patients who may benefit from endoscopic treatment targeting the EGJ.

Normative reference values for esophageal high-resolution manometry in healthy adults: A systematic review

Establishing normative values of high-resolution esophageal manometry is necessary for accurate interpretation and comparison of measurements. In this systematic review, we aimed to summarize normal values for different esophageal high-resolution manometry systems. Moreover, we assessed the effect of body position, bolus consistency, and provocative maneuvers on these normative thresholds. We searched Medline, Embase, and the Cochrane Library from January 1st, 2006, to January 20th, 2020, for studies that reported normative data of high-resolution manometry in healthy volunteers. We assessed methodological quality of the included studies and planned a descriptive analysis. We analyzed data from 54 articles describing normative thresholds in high-resolution manometry using solid-state or water-perfused systems. Forty-six studies performed the manometry study in the supine position with liquid swallows, whereas sixteen studies described normative values in the upright position. Twelve studies assessed normative values for different bolus consistencies, and nine studies evaluated different provocative maneuvers. There is a considerable variety of normative values for esophageal high-resolution manometry depending on the equipment used and the protocols performed to obtain measurements. This should be taken into account when evaluating measurements in clinical practice and when comparing results of published research studies.

Esophageal motility disorders on high-resolution manometry: Chicago classification version 4.0©

Chicago Classification v4.0 (CCv4.0) is the updated classification scheme for esophageal motility disorders using metrics from high-resolution manometry (HRM). Fifty-two diverse international experts separated into seven working subgroups utilized formal validated methodologies over two-years to develop CCv4.0. Key updates in CCv.4.0 consist of a more rigorous and expansive HRM protocol that incorporates supine and upright test positions as well as provocative testing, a refined definition of esophagogastric junction (EGJ) outflow obstruction (EGJOO), more stringent diagnostic criteria for ineffective esophageal motility and description of baseline EGJ metrics. Further, the CCv4.0 sought to define motility disorder diagnoses as conclusive and inconclusive based on associated symptoms, and findings on provocative testing as well as supportive testing with barium esophagram with tablet and/or functional lumen imaging probe. These changes attempt to minimize ambiguity in prior iterations of Chicago Classification and provide more standardized and rigorous criteria for patterns of disorders of peristalsis and obstruction at the EGJ.

Response to multiple rapid swallows shows impaired inhibitory pathways in distal esophageal spasm patients with and without concomitant esophagogastric junction outflow obstruction

Distal esophageal spasm (DES) is a motility disorder characterized by premature contraction of the esophageal body during single swallows. It is thought to be due to impairment of esophageal inhibitory pathways, but studies to support this are limited. The normal response to multiple rapid swallows (MRS) is deglutitive inhibition of the esophageal body during the MRS sequence. Our aim was to compare the response to MRS in DES patients and healthy control subjects. Response to MRS during HRM was evaluated in 19 DES patients (8 with and 11 without concomitant esophagogastric junction outflow obstruction [EGJOO]) and 24 asymptomatic healthy controls. Patients with prior gastroesophageal surgery, peroral endoscopic myotomy, pneumatic dilation, esophageal botulinum toxin injection within 6 months of HRM, opioid medication use, and esophageal stricture were excluded. Response to MRS was evaluated for complete versus impaired inhibition (esophageal body contractility with distal contractile integral [DCI] > 100 mmHg-sec-cm during MRS), presence of post-MRS contraction augmentation (DCI post MRS greater than single swallow mean DCI), and integrated relaxation pressure (IRP). Impaired deglutitive inhibition during MRS was significantly more frequent in DES compared to controls (89% vs. 0%, P < 0.001), and frequency was similar for DES with versus without concomitant EGJOO (100% vs. 82%, P = 0.48). The proportion of subjects with augmentation post MRS was similar for both groups (37% vs. 38%, P = 1.00), but mean DCI post MRS was higher in DES than controls (3360.0 vs. 1238.9, P = 0.009). IRP was lower during MRS compared to single swallows in all patients, and IRP during MRS was normal in 5 of 8 patients with DES and EGJOO. Our study suggests that impaired deglutitive inhibition during MRS is present in the majority of patients with DES regardless of whether they have concomitant EGJOO, and future studies should explore the usefulness of incorporating response to MRS in the diagnosis of DES.

Ineffective esophageal motility and bolus clearance. A study with combined high-resolution manometry and impedance in asymptomatic controls and patients

BACKGROUND

The definition and relevance of ineffective esophageal motility (IEM) remains debated. Our aim was to determine motility patterns and symptoms associated with IEM defined as impaired bolus clearance.

METHODS

To define altered bolus clearance, normal range of swallows with complete bolus transit (CBT) on high-resolution impedance manometry (HRIM) was determined in 44 asymptomatic controls. The results were then applied to a cohort of 81 patients with esophageal symptoms to determine the motility patterns which best predicted altered bolus clearance. Subsequently, in a cohort of 281 consecutive patients the identified motility patterns were compared with patients' customary symptoms.

KEY RESULTS

In asymptomatic controls, the normal range of swallows with CBT was 50%-100%. In patients, altered bolus transit (<50% CBT) was only associated with 30% or more failed contractions (P < .001). Neither weak peristalsis nor absence of contraction reserve (CR) was associated with altered bolus clearance. The patterns which best predicted altered bolus clearance were failed contractions ≥30% (specificity 88.2% and sensitivity of 84.6%), and ≥70% ineffective (failed + weak) contractions (sensitivity 84.6% and specificity 80.9%). No motility pattern was correlated to symptom scores.

CONCLUSIONS AND INFERENCES

Based on bolus clearance assessed by HRIM, ≥30% failed contractions and ≥70% ineffective contractions have the best sensitivity and specificity to predict altered bolus clearance. Weak contractions and absence of CR are not relevant with respect to bolus clearance.

Enhancing High-Resolution Esophageal Manometry: Use of Ancillary Techniques and Maneuvers

High-resolution manometry evaluates esophageal motor function using 10 supine water swallows. Superimposing impedance over high-resolution manometry pressure topography assesses the relationship between contraction and bolus propulsion and identifies inadequate clearance. Ancillary techniques and maneuvers augment the standard supine high-resolution manometry evaluation by challenging peristaltic function. Increasing bolus volume (rapid drink challenge) and altering bolus consistency (standardized test meal, solid swallows) enhance identification of esophageal outflow obstruction syndromes. Physiologic maneuvers (multiple rapid swallows, abdominal compression) address the ability of the esophageal smooth muscle to augment contraction vigor. Pharmacologic challenge is less commonly used clinically, and elucidates pathophysiology of esophageal motor disorders.

Prospective serial diagnostic study: the effects of position and provocative tests on the diagnosis of oesophageal motility disorders by high-resolution manometry

BACKGROUND

Standard high-resolution manometry (HRM) protocols are based on 10 single water swallows acquired in the supine position.

AIMS

To assess the impact of position, rapid drink challenge and solid test meal on the diagnosis of oesophageal motility disorders.

METHODS

Seventy-two healthy volunteers (20-76 years) and 366 consecutive patients (18-90 years) completed HRM with 10 single water swallows in the supine and upright positions. Rapid drink challenge was performed twice, before and after the solid test meal. Diagnosis based on single water swallows in the supine position (Chicago Classification v3.0) was compared with results in the upright position and with provocative tests.

RESULTS

Overall, diagnostic agreement in the supine and upright positions was present in 296/438 (67.6%) subjects. This increased to 90.0% when ineffective oesophageal motility was considered with normal motility. Integrated relaxation pressure was 4 mm Hg higher in the supine position. There was a higher prevalence of inconsistent, likely false positive, diagnoses of outlet obstruction in the supine compared to the upright position (16/20 vs 1/4 patients, P = 0.0007). Similarly, the difference in concordance for the diagnosis of oesophago-gastric junction obstruction or achalasia between single water swallows in the supine and upright positions with solid test meal was significant (12/29 (41.4%) vs 12/14 (85.7%), P = 0.0087).

CONCLUSION

Diagnostic agreement for oesophageal motility disorders based on single water swallows in the upright and supine positions was moderate, with frequent discordant findings for ineffective motility and outlet obstruction. HRM studies can be performed in either position, using appropriate reference values. Rapid drink challenge or solid test meal can resolve diagnostic discrepancies.

Minor esophageal functional disorders: are they relevant?

PURPOSE OF REVIEW

High resolution esophageal manometry (HRM) has expanded understanding of esophageal motor function. The Chicago Classification scheme has allowed systematic categorization of the myriad of manometric parameters identified during HRM. Multichannel intraluminal impedance pH has enhanced ambulatory reflux monitoring through complete assessment of esophageal content transit. However, the clinical implications of identified minor esophageal functional disorders remain unclear.

RECENT FINDINGS

Esophagogastric junction outlet obstruction is defined by esophagogastric junction obstruction with preserved peristalsis and may be managed expectantly, or in a manner similar to achalasia. Hypercontractile esophagus has been associated with dysphagia and non-cardiac chest pain, but the clinical significance is unclear as a majority of patients will improve without specific therapy. Additionally, these findings may be confounded by chronic opiate use. Ineffective esophageal motility is characterized by diminished esophageal contraction amplitude, potentially causing dysphagia and GERD. However, this is commonly identified in asymptomatic volunteers and may represent a normal variant. The multiple rapid swallow sequence can assess esophageal contraction reserve, which may predict post fundoplication dysphagia. The post-swallow induced peristaltic wave can serve as a surrogate of gastric refluxate clearance, providing important prognostic value. However, the associated time burden and lack of alternative therapeutic options limit its clinical utility.

SUMMARY

Minor esophageal functional disorders provide new therapeutic targets for symptomatic patients. However, these findings have inconsistent associations with symptoms and poorly defined therapeutic options. Minor esophageal function disorders should not be interpreted in isolation, with management decisions accounting for clinical, endoscopic, and radiographic factors in addition.

Lower oesophageal sphincter identification for gastro-oesophageal reflux monitoring: The step-up method revisited with use of basal impedance

Background

Oesophageal manometry is the gold standard for accurate positioning of multichannel intraluminal impedance pH (MII-pH) monitoring. The pH step-up method is not as accurate as oesophageal manometry and needs patients to be off proton pump inhibitor (PPI) therapy.

Objective

This study aimed to evaluate the feasibility of the impedance step-up method for lower oesophageal sphincter (LOS) localisation.

Methods

A total of 100 patients who underwent 24-hour MII-pH monitoring were enrolled. High-resolution manometry (HRM) was performed before MII-pH monitoring in order to locate the LOS by a different operator. The impedance step-up was defined as an increase of ≥50% with respect to gastric baseline. Lin's concordance correlation coefficient (ρ_c ) with 95% Bland-Altman limits of agreement (LOA) and Spearman's rho correlation coefficient were used when appropriate.

Results

The median impedance step-up was on average 0.8 cm caudal to the manometric upper border of the LOS. Agreement between two step-up impedance performances and inter-observer agreement were excellent (ρ_c  = 0.98 and 0.95), although the LOA ranges were wide (-2.4 to 4.0 cm). Impedance step-up performances were similar between patients off and on PPI.

Conclusions

We have described an alternative new method for pH impedance probe positioning using impedance step-up. Although less accurate than HRM in locating the LOS, it has excellent intra- and inter-observer agreement.

Jackhammer esophagus with and without esophagogastric junction outflow obstruction demonstrates altered neural control resembling type 3 achalasia

BACKGROUND

Esophageal hypercontractility can manifest with and without esophagogastric junction (EGJ) outflow obstruction. We investigated clinical presentations and motility patterns in patients with esophageal hypercontractile disorders.

METHODS

Esophageal HRM studies fulfilling Chicago Classification 3.0 criteria for jackhammer esophagus (distal contractile integral, DCI >8000 mmHg.cm.s in ≥ 20% swallows) with (n = 30) and without (n = 83) EGJ obstruction (integrated relaxation pressure, IRP > 15 mm Hg) were retrospectively reviewed from five centers (4 in Europe, 1 in US). Single swallows (SS) and multiple rapid swallows (MRS) were analyzed using HRM software tools (IRP, DCI, distal latency, DL); MRS: SS DCI ratio >1 defined contraction reserve. Comparison groups were achalasia type 3 (n = 72, positive control for abnormal inhibition and EGJ obstruction) and healthy controls (n = 18). Symptoms, HRM metrics, and MRS contraction reserve were analyzed within jackhammer subgroups and comparison groups.

KEY RESULTS

The esophageal smooth muscle was excessively stimulated at baseline in jackhammer subgroups, with lack of augmentation following MRS identified more often compared with controls (P = .003) and type 3 achalasia (P = .07). Consistently abnormal inhibition was identified in type 3 achalasia (47%), and to a lower extent in jackhammer with obstruction (37%, P = .33), jackhammer esophagus (28%, P = .01), and controls (11%, P < .01 compared with type 3 achalasia). Perceptive symptoms (heartburn, chest pain) were common in jackhammer esophagus (P < .01 compared with type 3 achalasia), while transit symptoms (dysphagia) were more frequent with presence of EGJ obstruction (P ≤ .01 compared with jackhammer without obstruction).

CONCLUSIONS AND INFERENCES

The balance of excessive excitation and abnormal inhibition defines clinical and manometric manifestations in esophageal hypercontractile disorders.

Clinical Characteristics and Outcomes of Patients With Postfundoplication Dysphagia

BACKGROUND & AIMS

Dysphagia is a consequence of antireflux surgery (ARS) for gastroesophageal reflux disease (GERD). We studied patient management and symptomatic outcomes.

METHODS

We performed a retrospective study of 157 consecutive adult patients with GERD (mean age, 65.1 ± 1.0 y; 72% female) who underwent ARS at a tertiary care center from 2003 through 2014. We characterized postfundoplication dysphagia using a self-reported Likert scale, which ranged from a low score of 0 (no dysphagia) to a high score of 4 (severe daily dysphagia); scores of 2 or more indicated clinically significant dysphagia. Postfundoplication dysphagia was categorized as early (≤6 wk after ARS) or late (>6 wk after ARS), and Kaplan-Meier analyses were used to assess the time to development of clinically significant dysphagia. We performed univariate and multivariate analyses to assess management response and identify factors associated with dysphagia. The primary aim was to determine the prevalence and clinical course of postfundoplication dysphagia in patients with GERD treated with ARS.

RESULTS

Of the 157 patients, 54.8% had early postfundoplication dysphagia (clinically significant in 20.4%); only 3.5% required endoscopic intervention. Over 2.1 ± 0.2 years of follow-up evaluation, 29 patients (18.5%) developed late postfundoplication dysphagia. Based on Kaplan-Meier analysis, the median time to clinically significant late postfundoplication dysphagia was 0.75 years (95% CI, 0.26-1.22). Of 13 patients (44.8%) who underwent endoscopic dilation, improvement was reported by 92.3%, with a mean decrease in dysphagia severity of 1.55 ± 0.3, based on the Likert scale. Prefundoplication dysphagia, early postfundoplication dysphagia, recurrent hiatal hernia, and lack of contraction reserve following multiple rapid swallows were univariate predictors of late postfundoplication dysphagia (P ≤ .04); lack of contraction reserve was associated independently with late postfundoplication dysphagia, based on multivariate logistic regression analysis (odds ratio, 3.73; 95% CI, 1.11-12.56).

CONCLUSIONS

Early and late postfundoplication dysphagia can be successfully managed conservatively or with endoscopic dilation, respectively. Lack of contraction reserve on multiple rapid swallows is associated independently with late postfundoplication dysphagia.

Ineffective esophageal motility: Concepts, future directions, and conclusions from the Stanford 2018 symposium

BACKGROUND

Ineffective esophageal motility (IEM) is a heterogenous minor motility disorder diagnosed when ≥50% ineffective peristaltic sequences (distal contractile integral <450 mm Hg cm s) coexist with normal lower esophageal sphincter relaxation (integrated relaxation pressure < upper limit of normal) on esophageal high-resolution manometry (HRM). Ineffective esophageal motility is not consistently related to disease states or symptoms and may be seen in asymptomatic healthy individuals.

PURPOSE

A 1-day symposium of esophageal experts reviewed existing literature on IEM, and this review represents the conclusions from the symposium. Severe IEM (>70% ineffective sequences) is associated with higher esophageal reflux burden, particularly while supine, but milder variants do not progress over time or consistently impact quality of life. Ineffective esophageal motility can be further characterized using provocative maneuvers during HRM, especially multiple rapid swallows, where augmentation of smooth muscle contraction defines contraction reserve. The presence of contraction reserve may predict better prognosis, lesser reflux burden and confidence in a standard fundoplication for surgical management of reflux. Other provocative maneuvers (solid swallows, standardized test meal, rapid drink challenge) are useful to characterize bolus transit in IEM. No effective pharmacotherapy exists, and current managements target symptoms and concurrent reflux. Novel testing modalities (baseline and mucosal impedance, functional lumen imaging probe) show promise in elucidating pathophysiology and stratifying IEM phenotypes. Specific prokinetic agents targeting esophageal smooth muscle need to be developed for precision management.

The Utility of Esophageal Motility Testing in Gastroesophageal Reflux Disease (GERD)

PURPOSE OF REVIEW

Here, we discuss how esophageal motor testing plays important roles in patients with suspected gastroesophageal reflux disease (GERD). In addition to guiding appropriate placement of catheters for ambulatory reflux monitoring, esophageal high-resolution manometry (HRM) rules out confounding diagnoses, such as achalasia spectrum disorders, that can present with symptoms similar to that of GERD, but are managed very differently.

RECENT FINDINGS

HRM performed with impedance in the post-prandial setting (PP-HRIM) can assess for rumination syndrome or supragastric belching, which should be directed towards behavioral interventions. The recent GERD Classification of Motor Function recommends a hierarchical approach, focusing on (1) the esophagogastric junction (EGJ), (2) the esophageal body, and (3) esophageal contraction reserve, which can be assessed with provocative maneuvers at HRM, such as multiple rapid swallows (MRS). This approach can inform the appropriate tailoring of antireflux surgery. Novel esophageal motility metrics, such as the EGJ-contractile integral from HRM, or post-reflux swallow-induced peristaltic wave indices from 24-h pH-impedance monitoring, may also assist with GERD diagnosis. Assessment of esophageal motor function can contribute in a significant manner to the care of patients with suspected GERD, particularly when esophageal symptoms do not improve with antisecretory therapy, and/or when surgical or endoscopic antireflux therapies are under consideration.

Evaluation of Esophageal Contraction Reserve Using HRM in Symptomatic Esophageal Disease

Esophageal high resolution manometry (HRM) is the gold standard for assessment of esophageal motor disorders, but motor responses to the standard 5 mL water swallow protocol may not provide precision in defining minor motor disorders. Provocative maneuvers, particularly multiple rapid swallows (MRS), have been used to assess deglutitive inhibition during the repetitive swallows, and the contractile response following the final swallow of the sequence. The augmentation of esophageal smooth muscle contraction following MRS is termed contraction reserve. This is determined as the ratio between esophageal body contraction vigor (distal contractile integral, DCI) following MRS to the mean DCI after single swallows, which is ≥1 in the presence of contraction reserve. Reliable assessment of contraction reserve requires the performance of 3 MRS maneuvers during HRM. Absence of contraction reserve is associated with a higher likelihood of late postfundoplication dysphagia and may correlate with higher esophageal reflux burden on ambulatory reflux monitoring. Esophageal motor responses to abdominal compression, functional lumen imaging probe (FLIP) balloon distension, and pharmacologic testing (using edrophonium and cisapride) may correlate with contraction reserve. Other provocative tests useful during HRM include rapid drink challenge, solid and viscous swallows, and standardized test meals, which are more useful in evaluation of esophageal outflow obstruction and dysphagia syndromes than in identification of contraction reserve. Provocative maneuvers have been recommended as part of routine HRM protocols, and while useful clinical information can be gleaned from these maneuvers, further research is necessary to determine the precise role of provocative testing in clinical esophagology.

Advancements in the use of manometry and impedance testing for esophageal functional disorders

The utilization of high-resolution manometry (HRM) has enhanced our understanding and assessment of esophageal motor disorders. Moreover, the combination of impedance technology with HRM (HRIM) has further improved our knowledge of esophageal physiology and the clinical evaluation of dysmotility, thanks to the addition of accurate measurement of bolus transit. Areas covered. This paper provides an overview of current knowledge in the use of HRIM for the study of esophageal functional disorders by reporting mainly the results of many publications and several systematic reviews in this field. Expert opinion. HRIM has represented a relevant improvement in the assessment of esophageal motility and has required the development of new metrics, such as the esophageal impedance integral ratio, the bolus flow time, the nadir impedance pressure and the impedance bolus height, which increase the evaluation of esophageal bolus transit. An extension of impedance is represented by functional lumen imaging probe (FLIP), which determines the biophysical properties and the distensibility of the esophagus and permits to detect contractility patterns not seen on HRM alone. We eagerly wait for a new and fruitful iteration of the Chicago Classification, now in version 3.0, which can cover the ongoing clinical experience of HRIM.

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.

Multiple rapid swallow testing in patients with gastroesophageal reflux disease

Patients with gastroesophageal reflux disease are commonly referred to a gastrointestinal motility unit for assessment of esophageal physiology tests prior to an anti-reflux procedure. On esophageal manometry, most patients have normal peristalsis; however, minor disorders of motility such as ineffective esophageal motility and fragmented peristalsis are not uncommon. Multiple rapid swallow (MRS) test is a provocative method for assessing peristaltic reserve in such patients. We report our single-center experience on MRS testing. ᅟ ᅟ.

Modern diagnosis of GERD: the Lyon Consensus

Clinical history, questionnaire data and response to antisecretory therapy are insufficient to make a conclusive diagnosis of GERD in isolation, but are of value in determining need for further investigation. Conclusive evidence for reflux on oesophageal testing include advanced grade erosive oesophagitis (LA grades C and D), long-segment Barrett's mucosa or peptic strictures on endoscopy or distal oesophageal acid exposure time (AET) >6% on ambulatory pH or pH-impedance monitoring. A normal endoscopy does not exclude GERD, but provides supportive evidence refuting GERD in conjunction with distal AET <4% and <40 reflux episodes on pH-impedance monitoring off proton pump inhibitors. Reflux-symptom association on ambulatory reflux monitoring provides supportive evidence for reflux triggered symptoms, and may predict a better treatment outcome when present. When endoscopy and pH or pH-impedance monitoring are inconclusive, adjunctive evidence from biopsy findings (histopathology scores, dilated intercellular spaces), motor evaluation (hypotensive lower oesophageal sphincter, hiatus hernia and oesophageal body hypomotility on high-resolution manometry) and novel impedance metrics (baseline impedance, postreflux swallow-induced peristaltic wave index) can add confidence for a GERD diagnosis; however, diagnosis cannot be based on these findings alone. An assessment of anatomy, motor function, reflux burden and symptomatic phenotype will therefore help direct management. Future GERD management strategies should focus on defining individual patient phenotypes based on the level of refluxate exposure, mechanism of reflux, efficacy of clearance, underlying anatomy of the oesophagogastric junction and psychometrics defining symptomatic presentations.

Esophageal provocation tests: Are they useful to improve diagnostic yield of high resolution manometry?

High resolution manometry (HRM) is the gold standard to diagnose esophageal motility disorders but has some limitations. The inclusion of provocative tests might enhance the diagnostic yield of HRM. These tests are easy to perform and to add to the regular manometry protocol. Multiple rapid swallows (MRS; 5 2-mL swallows) is useful to assess the contractile reserve and deglutitive inhibition. The optimal number of MRS to perform might be 3 as suggested by Mauro et al. in this issue of Neurogastroenterology & Motility. The absence of contractile reserve might be associated with gastro-esophageal reflux disease and with an increased risk of post fundoplication dysphagia. Single viscous and solid swallows might enhance the detection of esophageal motility disorders but are not significantly associated with symptom occurrence. Test meal has the advantage to represent a real-life scenario and is promising to depict significant motility findings responsible for esophageal symptoms. Post-prandial recording might also be of interest to diagnose rumination and belching disorders. The best indication of rapid drink challenge test (free drinking of 200 mL) is currently the diagnosis of esophago-gastric junction obstruction. Finally, abdominal compression might be an option to evaluate response of esophageal peristalsis in a context of outflow resistance as proposed by Brink et al. in this issue. These provocative maneuvers appear to provide a complementary role in the evaluation of esophageal motility but require prospective studies to determine the validity of the findings and whether they will lead to changes in clinical practice.