Anatomic abnormalities are common potential explanations of manometric esophagogastric junction outflow obstruction

Frequent discrepancies among diagnostic tests for detecting lower esophageal sphincter-related obstruction

BACKGROUND

There are frequent discrepancies among high-resolution manometry (HRM), functional lumen imaging probe (FLIP), and esophagram in identifying lower esophageal sphincter (LES)-related obstruction. We aimed to determine the frequency of those discrepancies and how they influenced clinical treatment/outcomes.

METHODS

We identified patients who had all three tests (HRM, FLIP, and esophagram) and endoscopy performed for evaluation of esophageal symptoms in our Center for Esophageal Diseases. Discrepancies among the tests for the presence of LES obstruction were noted, and the performance of individual tests was compared against a consensus opinion rendered by a panel of esophagologists. Binary logistical regression was performed, and ROC curves were generated for prediction of the consensus clinical diagnosis of LES obstruction.

KEY RESULTS

A total of 126 patients (mean age 57.9 ± 17.0 years; 67% female) met inclusion criteria. All three tests agreed on the presence or absence of LES obstruction in only 72 (57%) patients [no LES obstruction in 57 (45%), LES obstruction in 15 (12%)]. Thirteen patients (10%) had a change in management based on additional findings on FLIP +/- esophagram not seen on HRM with 69% having symptomatic improvement after LES-directed intervention. FLIP was the strongest predictor of a consensus diagnosis of LES obstruction by logistic regression and ROC (OR 23.36, AUC 0.796), followed by HRM (OR 15.41, AUC 0.764).

CONCLUSIONS & INFERENCE

High-resolution manometry, functional lumen imaging probe, and esophagram each have considerable limitations for identifying LES obstruction, and discrepancies among these tests occur frequently. Multimodal testing is often required for adequate evaluation of LES-related obstruction.

Natural history of symptoms and prognostic information of the rapid drink challenge and solid bolus swallows in esophagogastric junction outflow obstruction defined by manometry

BACKGROUND/INTRODUCTION

Esophagogastric junction outflow obstruction (EGJOO) is a condition characterized by poor relaxation of the lower esophageal sphincter (LES), which can manifest as dysphagia and chest pain. The best treatment of EGJOO is unknown as some patients improve without any specific therapy, whereas some patients undergo invasive therapy. Currently, prognostic factors are lacking. We aimed to assess the long-term prognosis and predictors of dysphagia and chest pain by the rapid drink challenge and solid bolus swallows in EGJOO.

METHODS

We retrospectively assessed high-resolution esophageal manometries (HRM) performed at our center between 2015 and 2018. The patients completed a dysphagia and chest pain questionnaire a median of 34 months after the HRM/baseline assessment, including the Impaction dysphagia questionnaire-10 (IDQ-10) complemented with questions regarding chest pain and esophageal treatments. Symptoms were compared with HRM findings.

RESULTS

In all, 980 HRMs were analyzed and 66 (6.5%) were identified as having HRM findings compatible with EGJOO. Of these, 27 patients with EGJOO (41%) completed the follow-up questionnaires and had no exclusion criteria, and 70% of these patients had dysphagia and 44% chest pain at least once a week. Dysphagia at follow-up was more common in patients with elevated integrated relaxation pressure (IRP) on all three HRM metrics (water swallows, solid bolus swallows, and rapid drink challenge) (p = 0.03, odds ratio: 8.4 (95% CI: 1.2-56.0)), but this was not seen for chest pain (p = 0.45). Abnormal motility patterns on rapid drink challenge or solid bolus swallows were not associated with dysphagia or chest pain at follow-up.

CONCLUSIONS

Having a high IRP on three HRM metrics-water swallows, solid bolus swallows, and rapid drink challenge-is associated with a worse prognosis in patients with EGJOO and could potentially be used to select candidates suitable for invasive procedures.

How to effectively use and interpret the barium swallow: Current role in esophageal dysphagia

BACKGROUND

The barium swallow is a commonly performed investigation, though recent decades have seen major advances in other esophageal diagnostic modalities.

PURPOSE

The purpose of this review is to clarify the rationale for components of the barium swallow protocol, provide guidance on interpretation of findings, and describe the current role of the barium swallow in the diagnostic paradigm for esophageal dysphagia in relation to other esophageal investigations. The barium swallow protocol, interpretation, and reporting terminology are subjective and non-standardized. Common reporting terminology and an approach to their interpretation are provided. A timed barium swallow (TBS) protocol provides more standardized assessment of esophageal emptying but does not evaluate peristalsis. Barium swallow may have higher sensitivity than endoscopy for detecting subtle strictures. Barium swallow has lower overall accuracy than high-resolution manometry for diagnosing achalasia but can help secure the diagnosis in cases of equivocal manometry. TBS has an established role in objective assessment of therapeutic response in achalasia and helps identify the cause of symptom relapse. Barium swallow has a role in the evaluating manometric esophagogastric junction outflow obstruction, in some cases helping to identify where it represents an achalasia-like syndrome. Barium swallow should be performed in dysphagia following bariatric or anti-reflux surgery, to assess for both structural and functional postsurgical abnormality. Barium swallow remains a useful investigation in esophageal dysphagia, though its role has evolved due to advancements in other diagnostics. Current evidence-based guidance regarding its strengths, weaknesses, and current role are described in this review.

Major mixed motility disorders: An important subset of esophagogastric junction outflow obstruction

BACKGROUND

Esophagogastric junction outflow obstruction (EGJOO) is an esophageal motility disorder characterized by a lack of relaxation of the esophagogastric junction (EGJ), with preserved esophageal body peristalsis. We propose new terminology for the coexistence of EGJOO with hypercontractile esophagus and distal esophageal spasm as a major mixed motility disorder (MMMD), and normal peristalsis or a minor disorder of peristalsis such as ineffective esophageal motility with EGJOO as isolated or ineffective EGJOO (IEGJOO).

METHODS

We reviewed prior diagnoses of EGJOO, stratified diagnoses as IEGJOO or MMMD, and compared their symptomatic presentations, high-resolution manometry (HRM) and endoluminal functional lumen imaging probe (EndoFLIP) metrics, and treatment responses at 2-6 months of follow-up.

RESULTS

Out of a total of 821 patients, 142 met CCv3 criteria for EGJOO. Twenty-two were confirmed by CCv4 and EndoFLIP as having EGJOO and were clinically managed. Thirteen had MMMD, and nine had IEGJOO. Groups had no difference in demographic data or presenting symptoms by Eckardt score (ES). HRM showed MMMD had greater distal contractile integral, frequency of hypercontractile swallows, and frequency of spastic swallows, and greater DI by EndoFLIP. Patients with MMMD showed greater reduction in symptoms after LES-directed intervention when measured by ES compared with IEGJOO (7.2 vs. 4.0).

CONCLUSION

Patients with MMMD and IEGJOO present similarly. Detectable differences in HRM portend different responses to endoscopic therapy. Because patients with MMMD have greater short-term prognosis, they should be considered a different diagnostic classification to guide therapy.

Opioid Exposure Differentially Impacts Esophageal Body Contraction Over the Lower Esophageal Sphincter

BACKGROUND & AIMS

Studies with limited sample sizes have investigated association of chronic opioid use with motility disorders of esophagogastric junction and esophageal body peristalsis. Our aims were to use a large cohort of patients to assess (1) the impact of opioid exposure on clinical and manometric characteristics, and (2) the association of opioid exposure with higher long-term symptom burden.

METHODS

Patients recruited from a tertiary medical center who underwent high-resolution manometry (HRM) between 2007 and 2018 were included. Demographics, opiate exposure, clinical symptoms, and HRM parameters were compared. Patient-Reported Outcomes Measurement Information System-Gastrointestinal swallowing domain (PROMIS-GI swallowing domain) and Eckardt score were administered via phone interviews in patients with hypercontractile esophagus (HE) or distal esophageal spasm (DES) to determine long-term symptom burden between opioid and nonopioid users.

RESULTS

Our cohort included 4075 patients (869 with opiate exposure with median morphine milligram equivalent [interquartile range] of 30 [10-45]). Patients in the opioid group were significantly more likely to have dysphagia (65% vs 51%, P < .01) and diagnosis of DES (11% vs 5%, P < .01) and HE (9% vs 3%, P < .01). Partial opioid agonists were not associated with motility abnormalities. Patients on opioids had significantly higher symptom burden on median (interquartile range) follow-up of 8.9 years (5.8-10.4) post manometric diagnosis with median PROMIS-GI swallowing domain score of 21.5 (17-25) compared with the nonopioid group at 15 (9.8-21, P = .03).

CONCLUSIONS

Nearly 2 of 3 patients with opioid exposure undergoing HRM have dysphagia and more than 25% of them with dysphagia as the primary symptom have a diagnosis of either DES or HE. Opioid users with spastic disorders have higher symptom burden long-term compared with nonopioid users.

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.

Nonachalasic esophageal motor disorders, from diagnosis to therapy

INTRODUCTION

Investigations conducted using conventional manometry and, recently, using high-resolution manometry (HRM), allowed us to explore the field of esophageal motility and understand the potential link between motor features and gastroesophageal reflux disease (GERD) pathogenesis. The management of patients with nonachalasic esophageal motor disorders is often challenging, due to the clinical heterogeneous presentation and the multifactorial nature of the mechanisms underlying symptoms.

AREAS COVERED

Several studies, carried out using HRM, have better interpreted the esophageal motor function in patients with esophagogastric junction outflow obstruction (EGJOO), distal esophageal spasm (DES), hypertensive esophagus, and hypomotility disorders. Moreover, HRM studies have shown a direct correlation between reduced esophageal motility, disruption of the esophagogastric junction, and gastroesophageal reflux burden.

EXPERT OPINION

Pathogenesis, clinical presentation, diagnosis, and treatment of nonachalasic esophageal motor disorders still represent a challenging area, requiring future evaluation by multicenter outcome studies carried out in a large cohort of patients and asymptomatic subjects. However, we believe that an accurate clinical, endoscopic, and HRM evaluation is, nowadays, helpful in addressing patients with nonachalasic esophageal motor disorders to optimal treatment options.

Can FLIP guide therapy in idiopathic esophagogastric junction outflow obstruction?

BACKGROUND

Esophagogastric junction outflow obstruction (EGJOO) has a variable disease course. Currently, barium swallow (BaS) and manometric parameters are used to characterize clinically significant EGJOO. The esophagogastric junction distensibility index (EGJ-DI) measured via functional lumen imaging probe (FLIP) can provide complementary information. Our aim was to assess symptom response in patients with EGJOO and an abnormal EGJ-DI after botulinum toxin (BT) treatment.

METHODS

A prospective cohort study of adults with idiopathic EGJOO was performed from September 2019 to March 2021. Patients with dysphagia underwent upper endoscopy with FLIP. If the EGJ-DI was abnormally low, BT was injected. Data examined included demographics, medical history, endoscopic and FLIP findings, BaS, manometry, and Eckardt score (ES). ES improvement was assessed via paired samples t-test. Pearson's chi-square tests were used to assess for associations.

RESULTS

Of the 20 patients, 75% had an abnormal EGJ-DI and underwent BT injections. Mean ES for patients with abnormal EGJ-DIs significantly improved from baseline to 1, 3, and 6 month follow-up (P-values: 0.01, 0.05, and 0.02, respectively). There was a significant association between an abnormal EGJ-DI with delayed bolus transit and presence of rapid drink challenge panesophageal pressurization on manometry: P = 0.03 and P = 0.03.

CONCLUSION

This prospective study revealed that an abnormal EGJ-DI can guide BT as assessed via symptomatic response. Additionally, abnormal EGJ-DI measurements were significantly associated with other parameters used previously to determine clinically relevant EGJOO. Larger follow-up studies are warranted to further elucidate guidance for therapy in EGJOO.

Predictors of Abnormal Functional Luminal Impedance Planimetry Findings in Non-mechanical Esophagogastric Junction Outflow Obstruction

BACKGROUND

Esophagogastric junction outflow obstruction (EGJOO) is a common but nonspecific motility pattern identified by esophageal high-resolution manometry (HRM). Functional luminal impedance planimetry (FLIP) provides information regarding lower esophageal sphincter (LES) mechanics, which can identify achalasia spectrum disorders and is useful in evaluating EGJOO. However, the relationship between HRM and FLIP parameters in EGJOO is not clearly defined.

AIMS

To identify predictors of abnormal FLIP findings in patients with non-mechanical EGJOO.

METHODS

This is a retrospective cohort study of patients with non-mechanical EGJOO who underwent FLIP between 10/1/16 and 7/1/19. Demographic data including age and gender, examination indication, concomitant medications, HRM parameters, symptom burden, and FLIP metrics of diameter and distensibility index (DI) were collected. DI was categorized as not low (DI > 2.8), borderline low (DI 1.1-2.8), and definitely low (DI ≤ 1). Kruskal-Wallis and Fisher's exact tests were used to assess the relationship between HRM and FLIP parameters and to identify predictors of abnormal FLIP.

RESULTS

Among the 44 patients studied, most were female (n = 33, 75%) and the median age was 63. The median IRP was 18.2, and 10 (23%) patients used chronic narcotics. Lower total heartburn and regurgitation scores, and LES diameter by FLIP are associated with definitely low DI.

CONCLUSIONS

In patients with non-mechanical EGJOO, reflux burden scores and FLIP diameters can aid in predicting DI. These results may provide useful adjunctive data to help in differentiating which patients have meaningful outflow obstruction.

Esophagogastric junction outflow obstruction

In the Chicago Classification version 4.0 (CCv4), esophagogastric junction outflow obstruction (EGJOO) is manometrically defined as an elevated median integrated relaxation pressure (IRP) and elevated intrabolus pressure (IBP) during supine wet swallows, and persistently elevated median IRP in the upright position. A clinically relevant conclusive diagnosis of EGJOO requires a manometric diagnosis of EGJOO and associated symptoms such as dysphagia and/or chest pain with at least one of the following supportive investigations (pharmacologic provocation, timed barium esophagogram, and/or endoflip). The Chicago Classification is intended for diagnosis of primary esophageal motor disorders, and thus history and endoscopic evaluation are important to exclude conditions (eg, previous surgery, strictures, or masses) that can secondarily generate the EGJOO pattern on HRM. While a manometric finding of EGJOO is often made and can be an early sign of achalasia, more often it is a manometric finding without clinical implications. The proposed changes in CC4.0 have attempted to make the diagnosis more specific, in order to reduce the number of clinically irrelevant diagnoses and avoid confusion by patients and physicians alike.

Diagnosis and Management of Achalasia: Updates of the Last Two Years

Achalasia is a rare neurodegenerative disorder causing dysphagia and is characterized by abnormal esophageal motor function as well as the loss of lower esophageal sphincter (LES) relaxation. The assessment and management of achalasia has significantly progressed in recent years due to the advances in high-resolution manometry (HRM) technology along with the improvements and innovations of therapeutic endoscopy procedures. The recent evolution of HRM technology with the inclusion of an adjunctive test, fluoroscopy, and EndoFLIP has enabled more precise diagnoses of achalasia to be made and the subgrouping into therapeutically meaningful subtypes. Current management possibilities include endoscopic treatments such as Botulinum toxin injected to the LES and pneumatic balloon dilation. Surgical treatment includes laparoscopic Heller myotomy and esophagectomy. Furthermore, in recent years, per oral endoscopic myotomy (POEM) has established itself as a principal endoscopic therapeutic alternative to the traditional laparoscopic Heller myotomy. The latest randomized trials report that POEM, pneumatic balloon dilatation, and laparoscopic Heller's myotomy have comparable effectiveness and complications rates. The aim of the current review is to provide a practical clinical approach to dysphagia and to shed light on the most recent improvements in diagnostics and treatment of achalasia over the last two years.

Esophagogastric junction outflow obstruction in the differential diagnosis of post-fundoplication dysphagia in children

INTRODUCTION AND AIMS

Post-fundoplication dysphagia is resolved with no therapeutic intervention in the majority of cases but it can persist in 5.3% of children that undergo the procedure. Among the differential diagnoses, esophagogastric junction outflow obstruction (EGJOO) is a disorder that should be suspected if there is a persistence of dysphagia. The aim of our study was to describe the clinical characteristics, treatment, and follow-up in a case series of patients diagnosed with post-fundoplication EGJOO.

MATERIALS AND METHODS

The clinical records of patients diagnosed with EGJOO at a tertiary care hospital within the time frame of September 2015 to September 2019 were reviewed, with respect to manometry, etiology, treatment, and clinical course of the disease.

RESULTS

Of the 213 high-resolution esophageal manometries performed, 4 patients met the criteria for post-fundoplication EGJOO. The primary symptom was dysphagia, presenting 15 days after the procedure. Esophageal dilations were carried out on all the patients but with no improvement. Symptoms related to the condition resolved spontaneously in three of the four patients.

CONCLUSION

The management of children with post-fundoplication EGJOO continues to be a challenge. Even though more than half of the cases resolve with no intervention, optimum management of the motility disorder is still limited, given the scant experience with the condition in the pediatric population.

The Clinical Relevance of Manometric Esophagogastric Junction Outflow Obstruction Can Be Determined Using Rapid Drink Challenge and Solid Swallows

INTRODUCTION

Esophagogastric junction outflow obstruction (EGJOO) defined on high-resolution esophageal manometry (HRM) poses a management dilemma given marked variability in clinical manifestations. We hypothesized that findings from provocative testing (rapid drink challenge and solid swallows) could determine the clinical relevance of EGJOO.

METHODS

In a retrospective cohort study, we included consecutive subjects between May 2016 and January 2020 with EGJOO. Standard HRM with 5-mL water swallows was followed by provocative testing. Barium esophagography findings were obtained. Cases with structural obstruction were separated from functional EGJOO, with the latter categorized as symptom-positive or symptom-negative. Only symptom-positive subjects were considered for achalasia-type therapies. Sensitivity and specificity for clinically relevant EGJOO during 5-mL water swallows, provocative testing, and barium were calculated.

RESULTS

Of the 121 EGJOO cases, 76% had dysphagia and 25% had holdup on barium. Ninety-seven cases (84%) were defined as functional EGJOO. Symptom-positive EGJOO subjects were more likely to demonstrate abnormal motility and pressurization patterns and to reproduce symptoms during provocative testing, but not with 5-mL water swallows. Twenty-nine (30%) functional EGJOO subjects underwent achalasia-type therapy, with symptomatic response in 26 (90%). Forty-eight (49%) functional EGJOO cases were managed conservatively, with symptom remission in 78%. Although specificity was similar, provocative testing demonstrated superior sensitivity in identifying treatment responders from spontaneously remitting EGJOO (85%) compared with both 5-mL water swallows (54%; P < 0.01) and barium esophagography (54%; P = 0.02).

DISCUSSION

Provocative testing during HRM is highly accurate in identifying clinically relevant EGJOO that benefits from therapy and should be routinely performed as part of the manometric protocol.

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.

Postobesity Surgery Esophageal Dysfunction: A Combined Cross-Sectional Prevalence Study and Retrospective Analysis

INTRODUCTION

Esophageal dysmotility including features of achalasia may develop because of bariatric surgery. However, the prevalence of these complications is unknown. We sought to define the prevalence of dysphagia and major esophageal motility disorders including achalasia after bariatric surgery through a large retrospective database review.

METHODS

Patients with a history of laparoscopic sleeve gastrectomy or Roux-en-Y gastric bypass who underwent a diagnostic high-resolution impedance manometry (HRIM) either before or after bariatric surgery across 3 large tertiary referral sites from June 2012 through February 2019 were identified from a procedural database. HRIM studies were interpreted per the Chicago classification v3.0 by a blinded investigator (K.R.). Demographic/clinical features were collected. In addition, patients who underwent bariatric surgery from January 2014 to April 2015 were contacted and administered a validated symptom assessment survey to gauge the overall prevalence of dysphagia in a postbariatric population.

RESULTS

A total of 137 patients were identified, including 97 who underwent HRIM after bariatric surgery (laparoscopic sleeve gastrectomy [n = 39, 40.1%]; Roux-en-Y gastric bypass [n = 58, 59.8%]) at a median of 5.84 years (interquartile range 2.1-12.5) postoperatively and 40 preoperative bariatric surgery candidates with medically complicated obesity. A manometric pattern consistent with achalasia was identified in 7 (7.2%) postsurgical patients compared with none in the preoperative group (P = 0.08). We further identified a separate achalasia-like pattern defined by aperistalsis and increased intragastric pressure (postobesity surgery esophageal dysfunction [POSED]) in 5 (5.2%) postsurgical patients vs none found preoperatively (P = 0.14). Achalasia or POSED was associated with postbariatric surgery (12.4% vs 0%, P = 0.02). Increasing time since surgery was independently associated with the development of achalasia (median 12.5 vs 5.8 years, P = 0.02), POSED (median 15.0 vs 5.8 years, P = 0.02) and major motility disorders (6.6 vs 4.9 years, P = 0.01). Furthermore, among 271 postbariatric surgery patients contacted for symptom assessment via survey, the prevalence of dysphagia was 13.7% at a mean 3.9 years after surgery.

DISCUSSION

Postoperative dysphagia is a common long-term complication of bariatric surgery. This is potentially the consequence of a time-dependent association with the development of postoperative esophageal dysmotility, particularly achalasia and POSED. Consequently, esophageal dysmotility may be an important under-recognized complication of bariatric surgery.

Low Yield of Cross-Sectional Imaging in Patients With Esophagogastric Junction Outflow Obstruction

Esophagogastric junction outflow obstruction (EGJOO) is an abnormal finding on high-resolution manometry (HRM) characterized by an elevated median integrated relaxation pressure with some intact peristalsis.¹ EGJOO is associated with heterogeneous symptoms, disease course, and response to treatment.^1-4 It can be idiopathic or secondary with causes including malignancy, infiltrative disease, or structural etiology.^1,3 Therefore, Chicago Classification of Esophageal Motility Disorders version 3.0 (CC v3.0) states a finding of EGJOO should prompt further investigation with cross-sectional imaging (CSI): endoscopic ultrasound (EUS) or computed tomography (CT) scan. However, there are limited data on the added yield of CSI to conventional modalities, namely esophagogastroduodenoscopy (EGD) and barium esophagram (BE). In previous studies, yield was small or unspecified.^2,5-8 The aim of this study was to examine the yield of CSI for diagnosing secondary causes of EGJOO.

Esophagogastric Junction Outflow Obstruction: Current Approach to Diagnosis and Management

PURPOSE OF REVIEW

We summarize the current epidemiology, presentation, diagnostic workup, and treatment of esophagogastric junction outflow obstruction (EGJOO). We also propose a treatment algorithm based upon the literature and our personal clinical experience.

RECENT FINDINGS

EGJOO can be caused by functional obstruction (akin to achalasia), mechanical obstruction, medications, or artifact. High-resolution esophageal manometry is currently the gold standard of diagnosis. Recent research on FLIP (functional lumen imaging probe) and timed barium support use as adjunctive testing. The diagnostic yield of cross-sectional imaging is low. Current diagnostic testing and treatment should be targeted to the suspected underlying etiology and clinical presentation of EGJOO. If functional obstruction is present with significant and persistent dysphagia, and either an abnormal FLIP or timed barium swallow, we consider therapy aimed at LES disruption (similar to achalasia). Pharmacologic therapy has a limited role. More research is needed on diagnostic and treatment modalities.

Management of Functional Esophagogastric Junction Outflow Obstruction: A Systematic Review

GOALS

Awareness of functional esophagogastric junction outflow obstruction (fEGJOO) has increased, but because there is no consensus on its management, we performed a systematic review of the literature to explore treatment strategies and outcomes.

BACKGROUND

EGJOO is a heterogenous disorder defined by high-resolution manometry parameters of elevated integrated relaxation pressure with preserved esophageal peristalsis. The etiology may be mechanical obstruction or idiopathic, the latter being fEGJOO.

STUDY

The PubMed/MEDLINE, Embase, and the Cochrane library electronic databases were searched through June 2018 for all studies of adult patients describing a treatment strategy for fEGJOO or incomplete lower esophageal sphincter relaxation. The search strategy yielded 1792 studies and 8 (0.4%) met inclusion criteria.

RESULTS

All but one included studies were retrospective (n=184 patients). There were 5 interventions described, with botulinum toxin (Botox) injection (n=69) and expectant management (n=82) the most frequently reported, with success rates of 58% and 54%, respectively. There was substantial heterogeneity among patients and treatments were not directly compared, though reported symptom resolution was similar among all strategies with a mean follow-up time of 15 months.

CONCLUSIONS

There are a variety of management strategies available for fEGJOO and some patients may not require any intervention. However, among 4 potential approaches aimed at disrupting lower esophageal sphincter hypertonicity, the largest existing evidence base supports either a therapeutic challenge of Botox injection or watchful waiting. Ultimately, these data indicate the need for further study with controlled trials to identify a definitive approach.

Esophagogastric junction outflow obstruction on manometry: Outcomes and lack of benefit from CT and EUS

BACKGROUND

Esophagogastric junction outflow obstruction (EGJOO) is a manometric diagnosis based on the Chicago Classification defined by inadequate relaxation of the gastroesophageal junction (GEJ) with swallowing, but with sufficient peristalsis such that the criteria for achalasia are not met. Possible causes include anatomical and functional etiologies. Further investigations, including computed tomography (CT) of the chest and endoscopic ultrasound (EUS), to help elucidate the etiology of EGJOO have been suggested, but the utility of this approach has not been proven.

METHODS

All new diagnoses of EGJOO made in the calendar years 2015-2016 were included. A review was performed for each patient to assess clinical outcomes, diagnostic, and therapeutic interventions after the EGJOO diagnosis.

KEY RESULTS

107 EGJOO patients were included. Their primary complaints were dysphagia (68%), chest pain (12%), reflux (8%), pre-operative assessment (6%), regurgitation (3%), and cough (3%). The mean IRP was 21.8 mm Hg. After a mean follow-up period of 463 days, the etiology of EGJOO remained undetermined in 67% of patients. 48% of patients were investigated with cross-sectional imaging (and 10% with EUS to rule out external compression or malignancy as a cause of EGJOO; none of these tests provided any further useful information). In only two cases did the EGJOO progress to achalasia.

CONCLUSIONS & INFERENCES

EGJOO is a manometric diagnosis with unclear clinical significance and outcome. CT and EUS of the GEJ were unhelpful at determining the cause of this entity. In this series, very few appear to progress to achalasia, none were due to malignancy, and many resolved spontaneously.

Pharmacologic interrogation of patients with esophagogastric junction outflow obstruction using amyl nitrite

BACKGROUND

The Chicago Classification of esophageal motility includes a group of patients who show evidence of esophagogastric junction outflow obstruction (EGJOO) as demonstrated by elevated integrated relaxation pressure (IRP) and preserved peristalsis. Our aim is to classify EGJOO patients based on response to amyl nitrite (AN) during high-resolution manometry.

METHODS

Patients were considered to have true EGJOO if elevated IRP during supine swallow persisted in the upright position and was associated with high intrabolus pressure. The EGJ response to AN was compared between patients with achalasia type 2 (A2) and normal esophageal motility. Based on the relaxation gain (deglutitive IRP-AN IRP) value that best discriminated these two groups (10 mm Hg), patients with true EGJOO were categorized as being in either the AN-responsive (AN-R) or AN-unresponsive (AN-U) subgroups.

KEY RESULTS

In the group of 49 patients with true EGJOO, the AN response classified 27 patients (IRP = 25 ± 10 mm Hg) with AN-R and 22 patients (IRP = 20 ± 5 mm Hg) with AN-U (P = 0.2). In AN-R, AN produced a relaxation gain and rebound after-contraction response at the EGJ comparable to A2 patients. AN-U patients had an elevated IRP after AN and a relaxation gain similar to normal esophageal motility patients. AN-U patients were obese and had higher prevalence of sleep apnea (P < 0.05).

CONCLUSIONS

Among patients with true EGJOO, only half have pharmacologic evidence of impaired LES relaxation. Pharmacologic interrogation of the EGJ is thus necessary to identify the subgroup of EGJOO patients who could be expected to benefit from LES ablative therapies.

Early Phase of Achalasia Manifested as an Esophageal Subepithelial Tumor

The Chicago classification (CC) defines an esophagogastric junction outflow obstruction (EGJOO) as the presence of several instances of intact or weak peristalsis, elevated median integrated relaxation pressure above 15 mmHg, and a discrepancy from the criteria of achalasia. The revised CC addresses the potential etiology of EGJOO, including the early forms of achalasia, mechanical obstruction, esophageal wall stiffness, or manifestation of hiatal hernia. A 58-year-old woman visited the Presbyterian Medical Center with swallowing difficulty. The patient underwent a high resolution manometry (HRM) examination and was diagnosed with EGJOO. Chest CT was performed to exclude a mechanical obstruction as a cause, and CT revealed a subepithelial tumor (SET) at the upper part of the esophagogastric junction. Therefore, laparoscopic surgery was performed and eccentric muscular hypertrophy of the distal esophagus was observed. Longitudinal myotomy and Dor fundoplication were also performed. The histology findings of the surgical specimens were consistent with achalasia. This paper reports a case of early achalasia that was finally diagnosed by the histology findings, but was initially diagnosed as EGJOO using HRM and misdiagnosed as SET in the image study.

Detection of hiatal hernias: comparison of high-resolution manometry and physician reported in an obese-predominant population

Background

The diagnosis of a hiatal hernia (HH) can be made by barium oesophagram or upper endoscopy. Data regarding the ability of high-resolution manometry (HRM) with oesophageal pressure topography (OPT) to identify HH remains limited. We aim to assess the diagnostic accuracy of the automated localisation on high-resolution manometry compared with physician visual interpretation on the detection of HH.

Methods

Patients (n=181) from West Virginia, Pennsylvania, Maryland, Virginia and Ohio, undergoing HRM with OPT from 1 January 2015 to 1 December 2017 were reviewed. The BMIs of this patient population are of the highest in the USA. Demographics, presenting symptoms, laboratory data, endoscopic findings, radiographic findings, and HRM findings were collected. Diagnosis of HH through HRM automated identification of oesophageal landmarks were compared with diagnosis by physician visual interpretation of OPT.

Results

Automated identification of HH using HRM had high specificity (99.1%), but low sensitivity (11.4%). Physician visual interpretation of OPT similarly had high specificity (82.9%, 83.8%), but low sensitivity (30.0%, 28.6%). Automated identification of HH had a greater positive predictive value (88.9%) compared with physician visual interpretation (52.5%, 52.6%) but was found to have a similar negative predictive value (63.9%) as physician visual interpretation (65.3%, 65.0%).

Conclusion

Compared with physician visual interpretation of OPT, automated identification of HH was more specific, but less sensitive in the diagnosis of HH. Use of automated identification of HH using HRM alone may lead to an increased number of false negatives, and subsequent underdiagnosis of this condition.

Combined Multichannel Intraluminal Impedance and High-resolution Manometry Improves Detection of Clinically Relevant Esophagogastric Junction Outflow Obstruction

BACKGROUND/AIMS

Esophagogastric junction outflow obstruction (EGJOO) is a diagnostically heterogeneous group with variable clinical relevance. We studied whether evaluation of bolus transit by multichannel intraluminal impedance (MII) is useful for discriminating clinically relevant EGJOO.

METHODS

A total 169 patients diagnosed as having EGJOO between June 2011 and February 2018 were analyzed. All the patients received a combined MII and high-resolution manometry (CMII-HRM). MII was reported as having abnormal liquid bolus transit (LBT) if ＜ 80% of swallows had complete bolus transit. EGJOO was defined as a median integrated relaxation pressure of ＞ 20 mmHg and when the criteria for achalasia were not met. Patients who progress to achalasia, show significant passage disturbance, or require pneumatic dilatation were defined as having a clinically relevant EGJOO.

RESULTS

Among the patients with EGJOO (n = 169), the clinically relevant group (n = 10) is more likely to have dysphagia (100% vs 25.2%, P ＜ 0.001), compartmentalized pressurization (CP; 90.0% vs 22.0%, P ＜ 0.001), and abnormal LBT (100% vs 66.7%, P = 0.032) compared to the non-relevant group (n = 159). The combination of dysphagia, CP, and abnormal LBT showed the best predictive power for clinically relevant EGJOO (sensitivity 90%, specificity 92.5%, positive predictive value 42.9%, negative predictive value 99.3%, positive likelihood ratio 11.9, and negative likelihood ratio 0.1). When CMII-HRM was used, an additional 8.3% of clinically relevant EGJOO cases were identified as compared with HRM alone.

CONCLUSION

Clinically relevant EGJOO can be predicted using CMII-HRM.

Utility of Esophageal High-Resolution Manometry in Clinical Practice: First, Do HRM

Esophageal high-resolution manometry (HRM) has advanced the understanding of esophageal motor function and the ability to diagnose and manage disorders of esophageal motility. In this review, we describe the indications for and the technical performance of HRM. The Chicago classification of esophageal motor function, now in its third iteration, streamlines and standardizes the nomenclature and basic interpretation of HRM data depicted as Clouse topographic plots. In clinical practice, HRM is an important diagnostic test for patients with dysphagia as well as patients with suspected gastroesophageal reflux disease (GERD), particularly in those patients with a suboptimal symptomatic response to antisecretory therapy. HRM can support diagnoses such as achalasia, as well as provide evidence for behavioral disorders such as rumination syndrome or supragastric belching with the assistance of postprandial HRM with impedance. Further, the GERD classification of motor function introduces a three-part hierarchical evaluation of esophageal motor function in GERD, highlighting the value of assessment of esophageal contractile reserve through provocative maneuvers during HRM such as multiple rapid swallows.

Evaluation of symptomatic esophagogastric junction outflow obstruction

BACKGROUND AND AIM

Esophagogastric junction outflow obstruction (EGJOO) may be due to anatomical abnormalities, but it is unclear how to evaluate them after high-resolution manometry. We aimed to determine (i) clinical and high-resolution manometry parameters differentiating anatomical EGJOO from functional EGJOO, (ii) investigations chosen and yield for anatomical EGJOO, and (iii) clinical outcomes of functional EGJOO.

METHODS

Medical records of consecutive patients with symptomatic EGJOO from February 2012 to December 2015 were reviewed. EGJOO was defined as anatomical if investigations identified a macroscopic or microscopic pathology accounting for EGJOO.

RESULTS

Forty of 292 (13.7%) had EGJOO, of which 6/40 (15%) had anatomical EGJOO (two PPI-responsive esophageal eosinophilia, two infiltrating cancers, and two external compressions). Anatomical EGJOO was more likely to present with dysphagia (100% vs 29.4%, P = 0.001) and less likely with regurgitation (0% vs 41.2%, P = 0.05). Anatomical EGJOO had higher frequencies of premature contraction (50% vs 5.9%, P = 0.003) and lower mean values of distal latency (5.6 +/- 1.3 vs 6.7 +/- 1.2, P = 0.004). Computed tomography scans revealed 50% (3/6) of etiologies of anatomical EGJOO. Approximately, 73.5% (25/34) of patients with functional EGJOO had spontaneous resolution of their symptoms. One underwent pneumatic dilatation with symptom resolution while remaining eight with persistent symptoms were attributed to gastroesophageal reflux disease.

CONCLUSION

Anatomical causes are present in 15% of EGJOO. Evaluation is warranted especially in patients presenting with dysphagia. Esophageal biopsies, barium swallows, computed tomography scans, and endoscopic ultrasound are complementary in EGJOO evaluation. In patients with non-obstructive symptoms and no anatomical etiologies, monitoring for spontaneous resolution is an option.

Clinical and manometric characteristics of patients with oesophagogastric outflow obstruction: towards a new classification

Background

The Chicago Classification (CC) defines oesophagogastric junction outflow obstruction (EGJOO) as the presence of an elevated integrated residual pressure (IRP) together with preserved oesophageal body peristalsis but its clinical significance is evolving.

Aims

To describe the clinical and manometric characteristics in patients with EGJOO and propose a new classification.

Methods

In this retrospective cohort study, patients with functional oesophageal symptoms underwent clinical and endoscopic assessment and oesophageal high-resolution manometry (HRM). The CC V.3 was used to define and redefine abnormalities.

Results

Of 478 HRM studies performed, EGJOO, defined as median IRP >15 mm Hg, was diagnosed in 116 patients; 17 underwent a follow-up HRM. Forty-four patients had otherwise normal oesophageal motility, with the only finding being EGJOO; 14 had achalasia, 19 had EGJOO plus ineffective oesophageal motility (IEM), 28 had EGJOO plus diffuse oesophageal spasm (DES) (n=25) or jackhammer oesophagus (n=3), and 11 had EGJOO plus IEM and DES. Patients with EGJOO+IEM had lower distal contractile integral (DCI) while those with EGJOO+DES had higher DCI. All groups exhibited high percentages of incomplete bolus clearance. On repeat studies, EGJOO preceded or followed another HRM diagnosis and remained permanent in 2/17 patients. Only one patient transitioned to achalasia.

Conclusions

The new classification further defines EGJOO by considering abnormalities in the body of the oesophagus that could contribute to symptoms or require therapy. Most patients with EGJOO have a coexisting motility disorder and do not have isolated EGJOO. There is a fluidity of the HRM diagnosis that needs to be considered prior to therapy.

Pressure exposure and catheter impingement affect the recorded pressure in the Manoscan 360™ system

BACKGROUND

The accuracy of pressure measurements by Manoscan high-resolution manometry (HRM) system is affected by pressure drift (PD). The PD is partly related to temperature and study duration, but other factors that contribute to errant pressure recording have not been systematically evaluated. The aim of this study was to investigate and quantify contributing factors to pressure recording error.

METHODS

In total, 660 in vitro experiments were conducted on seven HRM catheters to determine the effects of sustained pressure exposure, catheter impingement, temperature, duration of study, and immersion in saline or acid on recorded pressure and PD.

KEY RESULTS

At room temperature and without application of pressure, the PD was negligible. Application of sustained pressure significantly increased PD and catheter impingement of even 15° produced remarkable increases in the recorded pressure as well as post-recording PD. There was significant variability across sensors in their propensity to develop PD with temperature. Body (37°C) and freezing (0°C) temperatures resulted in significantly higher absolute value of PD in the opposite algebraic direction, respectively (for individual sensors). Although the overall trend was for higher PD with increasing temperature, some of the pressure sensors demonstrated inherently negative PD at body temperature.

CONCLUSIONS AND INFERENCES

In addition to the known effects of temperature, both sustained pressure exposure and catheter impingement significantly affect the recorded pressure and the magnitude of the PD observed at the end of the recording. These effects can be substantial enough to result in erroneous manometric diagnoses.

Clinicomanometric factors associated with clinically relevant esophagogastric junction outflow obstruction from the Sandhill high-resolution manometry system

BACKGROUND

Integrated relaxation pressure (IRP) is a key metric for diagnosing esophagogastric junction outflow obstruction (EGJOO). However, its normal value might be different according to the manufacturer of high-resolution manometry (HRM). This study aimed to investigate optimal value of IRP for diagnosing EGJOO in Sandhill HRM and to find clinicomanometric variables to segregate clinically relevant EGJOO.

METHODS

We analyzed 262 consecutive subjects who underwent HRM between June 2011 and December 2016 showing elevated median IRP (> 15 mm Hg) but did not satisfy criteria for achalasia. Clinically relevant subjects were defined as follows: (i) subsequent HRM met achalasia criteria during follow-up (early achalasia); (ii) Eckardt score was decreased at least two points without exceeding a score of 3 after pneumatic dilatation (variant achalasia); and (iii) significant passage disturbance on esophagogram without structural abnormality (possible achalasia).

KEY RESULTS

Seven subjects were clinically relevant, including two subjects with early achalasia, four subjects with variant achalasia, and one subject with possible achalasia. All clinically relevant subjects had IRP 20 mm Hg or above. Among subjects (n = 122) with IRP 20 mm Hg or more, clinically relevant group (n = 7) had significantly higher rate of dysphagia (100% vs 24.3%, P < .001) and compartmentalized pressurization (85.7% vs 21.7%, P = .001) compared to clinically non-relevant group (n = 115).

CONCLUSIONS & INFERENCES

Our results suggest that IRP of 20 mm Hg or higher could segregate clinically relevant subjects showing EGJOO in Sandhill HRM. Additionally, if subjects have both dysphagia and compartmentalized pressurization, careful follow-up is essential.

Understanding the Chicago Classification: From Tracings to Patients

Current parameters of the Chicago classification include assessment of the esophageal body (contraction vigour and peristalsis), lower esophageal sphincter relaxation pressure, and intra-bolus pressure pattern. Esophageal disorders include achalasia, esophagogastric junction outflow obstruction, major disorders of peristalsis, and minor disorders of peristalsis. Sub-classification of achalasia in types I, II, and III seems to be useful to predict outcomes and choose the optimal treatment approach. The real clinical significance of other new parameters and disorders is still under investigation.

The clinical significance of esophagogastric junction outflow obstruction and hypercontractile esophagus in high resolution esophageal manometry

BACKGROUND

Although major manometric abnormalities, the significance of esophagogastric junction outflow obstruction (EGJOO) and hypercontractile esophagus (HE) is poorly understood. We sought to determine long term outcomes for EGJOO and HE.

METHODS

High-resolution impedance manometry (HRIM) studies conducted from 5/30/2012 to 8/1/2014 consistent with EGJOO and HE and normal studies from 5/30/12 to 11/1/12 were identified. Standardized follow up was conducted with a phone survey utilizing the impact dysphagia questionnaire (IDQ-10).

KEY RESULTS

56 EGJOO, 40 HE patients and 33 controls were identified. Structural evaluation with EGD and esophagram did not differ among groups. Use of opiates in EGJOO (P<.05) and of anticholinergics in EGJOO and HE patients was more prevalent than in controls (P<.005). Dysphagia was more common in EGJOO (P<.05) and chest pain more common in HE (P<.005) at presentation. While HE patients were more likely to be symptomatic (P<.05), the majority of EGJOO and HE patients overall were asymptomatic at a mean 2.8 years follow up without medical or procedural intervention in the majority (72.5%). Symptom persistence at follow up was predicted by maximum distal contractile integral (DCI) and IRP in both EGJOO and HE (P<.05).

CONCLUSIONS & INFERENCES

The majority of patients with EGJOO and HE appear to have a benign clinical course similar to controls in the absence of specific treatment. However, the combination of abnormal IRP and DCI in both HE and EGJOO appears to discriminate an important subset of patients who may benefit from treatment. Further refinement of manometric criteria may therefore provide more useful clinical definitions of EGJOO and HE.

Bolus clearance in esophagogastric junction outflow obstruction is associated with strength of peristalsis

BACKGROUND

A manometric diagnosis of esophagogastric junction outflow obstruction (EGJOO) without a mechanical cause creates a therapeutic conundrum. The aim of this study was to assess esophageal bolus clearance in EGJOO and assess manometric factors associated with clearance in EGJOO.

METHODS

Bolus clearance was assessed using line-tracing method and contour method to determine Complete Bolus Transit (CBT) and Functional Clearance (FC), respectively, on combined High-Resolution Impedance Manometry (HRIM). HRIM studies of EGJOO patients, as well as a sample of achalasia types I-III and asymptomatic controls, were retrospectively analyzed. In EGJOO, associations between Integrated Relaxation Pressure (IRP) or Distal Contractile Integral (DCI) and clearance were assessed using receiver-operating-characteristic (ROC) curves.

KEY RESULTS

Seventy-five EGJOO, 28 achalasia, and 11 normal subjects were included. Agreement between CBT and FC was good (Kappa=0.75). CBT across swallows in each group was as follows: type I achalasia: 14%, type II achalasia: 8%, type III achalasia: 61%, EGJOO: 86%, and normal: 98% (p values .023, .006, and <.0001 for EGJOO vs normals, type III achalasia, and all achalasia, respectively). In idiopathic EGJOO, CBT ≥60% of swallows was seen in 96.4% of patients when mean DCI>610 mmHg-s-cm (accuracy 87.7%, P=.004). Complete Bolus Transit( CBT) across individual swallows was 97.8% when DCI>884 mmHg-s-cm (accuracy 81.9%, P<.0001). IRP was poorly associated with bolus clearance.

CONCLUSIONS & INFERENCES

Bolus clearance in EGJOO is impaired compared to normal, but not as severely as in achalasia. In idiopathic EGJOO, weak peristalsis is associated with poor bolus clearance. Bolus transit appears to be unimpaired when DCI>900 mmHg-s-cm.

Primary Esophageal Motility Disorders: Beyond Achalasia

The best-defined primary esophageal motor disorder is achalasia. However, symptoms such as dysphagia, regurgitation and chest pain can be caused by other esophageal motility disorders. The Chicago classification introduced new manometric parameters and better defined esophageal motility disorders. Motility disorders beyond achalasia with the current classification are: esophagogastric junction outflow obstruction, major disorders of peristalsis (distal esophageal spasm, hypercontractile esophagus, absent contractility) and minor disorders of peristalsis (ineffective esophageal motility, fragmented peristalsis). The aim of this study was to review the current diagnosis and management of esophageal motility disorders other than achalasia.

Clinical presentation and disease course of patients with esophagogastric junction outflow obstruction

Esophagogastric junction outflow obstruction, characterized by preserved peristalsis in conjunction with an elevated integrated relaxation pressure, can result from specific anatomic variants or may represent achalasia in evolution. There is limited information on the clinical significance of this diagnosis. The aim of this study is to describe the clinical characteristics and outcomes in our cohort of patients with esophagogastric junction outflow obstruction.Consecutive adult patients who had undergone high-resolution esophageal manometry between February 2013 and November 2015 with a diagnosis of esophagogastric junction outflow obstruction were identified. Electronic medical records were reviewed to determine: (1) secondary causes of esophagogastric junction outflow obstruction; (2) treatment; and (3) natural history. Improvement in symptoms noted during follow-up evaluation was considered to be a favorable outcome. Worsening of symptoms or no change in symptoms was considered to be an unfavorable outcome.Of 874 manometries performed during this time period, 83 met the criteria for esophagogastric junction outflow obstruction. Of these patients, 11 had secondary causes: paraesophageal hernia (4), Nissen fundoplication (2), esophageal stricture (3), prior laparoscopic band placement (1), and diverticulum (1). All of these secondary causes were identified by barium esophagram. The remaining 72 patients were categorized as idiopathic esophagogastric junction outflow obstruction. Two patients developed type II achalasia on follow-up. An additional two patients had no symptoms as testing was performed for preoperative evaluation prior to bariatric surgery, leaving 68 patients for symptom follow-up analysis. Of these, 19 had a favorable outcome, 18 had an unfavorable outcome, and 31 were lost to follow-up. Of those with a favorable outcome, 6 patients underwent treatment: medication (3), botulinum toxin injection followed by laparoscopic Heller myotomy (1), botulinum toxin injection and medication (1), and bougie dilation (1). Of the 18 patients with an unfavorable outcome, 6 patients underwent treatment: botulinum toxin injection (5) and medication (1). Computed tomography scan or endoscopic ultrasound was performed in 40% of patients with available follow-up and none of these studies revealed secondary causes. The overall median follow-up time was 5 months.Esophagogastric outflow obstruction is a manometric finding of unclear significance. Secondary causes should first be excluded with structural studies. The evolution of esophagogastric junction outflow obstruction to achalasia is rare. Symptoms in patients with esophagogastric junction outflow obstruction do not always require treatment and treatment response is variable. The challenge in managing these patients lies in distinguishing which patients will need intervention. Further studies are needed for consideration of subgrouping this disease or modifying the categorization into clinically relevant entities.

Chicago Classification of Esophageal Motility Disorders: Applications and Limits in Adults and Pediatric Patients with Esophageal Symptoms

The Chicago classification (CC) is most valued for its systematic approach to esophageal disorders and great impact in unifying practice for esophageal manometric studies. In view of the ever-growing wealth of knowledge and experience gained by the expanding use of high-resolution manometry (HRM) in various clinical scenarios, the CC is regularly updated. Its clinical impact and ability to predict clinical outcome, both in adults and pediatrics, will be further promoted by recognizing its current limitations, incorporating new metrics in its diagnostic algorithms and adjusting the HRM protocols based on the clinical question posed. Herein, we discuss the current limitations of the CC and highlight some areas of improvement for the future.