Technology insight: The role of impedance testing for esophageal disorders

Classic techniques like videofluoroscopy, stationary manometry, and ambulatory 24 h pH-metry are routinely used in the clinic to study patients with dysphagia, chest pain and reflux-related symptoms. Although these techniques have been very useful over the years, both for diagnosis and for therapeutic guidance, there are still many patients with dysphagia or chest pain who remain undiagnosed even after testing, and patients with typical and atypical symptoms of gastroesophageal reflux disease, with normal pH-metry findings, who do not respond adequately to antisecretory therapy. Esophageal impedance monitoring is a new technique that can be used alone and in combination with pH-metry and manometry to evaluate bolus transport and all types of gastroesophageal reflux (acid and nonacid). This review describes the esophageal impedance monitoring technique and summarizes the published validation studies that compare impedance monitoring with other methods, as well as normal values and reproducibility of impedance patterns and their association with symptoms.     

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.     

Esophageal 24-h pH monitoring: is prior manometry necessary for correct positioning of the electrode?

In 24-h esophageal pH monitoring, the electrode is usually positioned 5 cm above the manometrically localized esophagogastric junction. In order to replace esophageal manometry for this purpose, we tested whether the esophagogastric junction can be identified correctly by fluoroscopy or the determination of the pH-step between stomach and esophagus, compared with esophageal manometry. The distance from the nares to the esophagogastric junction was determined three times with each of the three methods in 46 patients and 14 volunteers. Fluoroscopy assumed the esophagogastric junction 1.23 +/- 0.23 cm (mean +/- SE) lower than the peak pressure point determined at manometry, pH-step only 0.45 +/- 0.16 cm. With pH-step, only one subject had a difference of more than 3 cm to the manometrically defined esophagogastric junction, whether gastroesophageal reflux disease (as proven by pH monitoring) was present or not. We conclude that the esophagogastric junction can usually be identified with sufficient accuracy by the measurement of the pH-step between stomach and esophagus. Fluoroscopy is far less accurate than pH-step, and should not be used.     

Impact of endoscopic suturing of the gastroesophageal junction on lower esophageal sphincter function and gastroesophageal reflux in patients with reflux disease

OBJECTIVES: Plication of the gastroesophageal junction by endoscopic suturing has been reported to improve symptoms and reduce acid exposure in patients with gastroesophageal reflux disease (GERD). The mechanisms underlying these effects are not well defined. The aims of our study were to determine the impact of endoscopic suturing of the gastroesophageal junction on lower esophageal sphincter (LES) function in patients with GERD. METHODS: In 15 patients (7 males) with GERD (heartburn, % time esophageal pH < 4 greater than 4%, +/- history of erosive esophagitis within 6 months), two plications were performed circumferentially 1 cm below the gastroesophageal junction. Endoscopy and combined postprandial esophageal manometry and pH monitoring were performed before and 6 months after treatment; 24-h ambulatory pH monitoring and symptom assessment were also performed before, and at 6 and 12 months after treatment. RESULTS: Six months after treatment, the rate of transient LES relaxations (tLESRs) was decreased by 37% (p < 0.05) and basal LES pressure had increased from 4.3 +/- 2.2 mmHg to 6.2 +/- 2.1 mmHg (p < 0.05). The rate of postprandial reflux events and acid exposure time were not altered. Endoscopic suturing significantly reduced 24-h esophageal acid exposure from 9.6% (9.0-12.1) to 7.4% (3.9-10.1) at 6 months, due predominantly to a reduction in upright acid exposure. The reduction in total 24-h acid exposure was sustained to 12 months. At repeat endoscopy, only one plication was evident in 6 patients (40%) at 6 months. Seven patients (47%) remained off medications at 6 and 12 months follow-up. CONCLUSIONS: In patients with GERD, endoscopic suturing of the gastroesophageal junction results in a reduction in the rate of tLESRs, and an increase in basal LES pressure. These changes in LES function result in only a modest reduction in gastroesophageal reflux.     

Twenty-four-hour ambulatory versus stationary esophageal manometry in the evaluation of esophageal motility in patients with gastroesophageal reflux disease

BACKGROUND: Although stationary manometry commonly reveals esophageal body motility disorders in patients with gastroesophageal reflux disease (GERD), esophageal function cannot be fully and precisely assessed during normal daily activities by this investigatory modality. AIM: To compare the results of 24-hour ambulatory manometry with those of stationary manometry and to determine the specificity and accuracy of the former to detect motility disorders in patients with GERD. PATIENTS AND METHODS: 15 patients with documented GERD were included in the study. Clinical assessment, upper alimentary endoscopy and stationary manometry as well as 24-hour ambulatory manometry with concomitant 24-hour monitoring of the esophageal pH were performed in each patient. RESULTS: 24-hour ambulatory manometry revealed a significant number of dropped or interrupted esophageal contractions in patients who were found to have only complete peristalsis on stationary manometry. Furthermore, in certain patients, ambulatory manometry detected an increased incidence of dropped or interrupted contractions as compared to those recorded during stationary manometry. Ineffective contractions, suggestive of poor esophageal motility, although absent on stationary manometry, were detected in a large number of patients during a 24-hour period of recording. Also, the amplitude of esophageal contractions was clearly overestimated when evaluated by stationary manometry. CONCLUSIONS: 24-hour ambulatory esophageal manometry reveals esophageal motor abnormalities to a greater extent than those demonstrated at stationary manometry, in patients with GERD. This might be of significance in designing the treatment and predicting possible outcome.     

Impaired visceral sensitivity to acid reflux in patients with Barrett''s esophagus. The role of esophageal motility*

Patients with Barrett's esophagus have been reported to have impaired visceral sensitivity to acid perfusion and distension compared with non-Barrett's refluxers, but the mechanism is poorly understood. Esophageal motility and clearance mechanisms may be important, and this study explored the relationship of motility with symptoms. Seventy-four patients with Barrett's esophagus were compared with 216 patients with gastro-esophageal reflux disease (GERD) with abnormal acid reflux scores, and 50 symptomatic patients who had normal acid exposure. All patients had esophageal manometry and 24-h pH monitoring. Thirty-six Barrett's patients also had 24-h bile reflux monitoring. Symptoms were assessed by Symptom Index (SI) during 24-h pH monitoring. Barrett's patients with normal motility had a significantly lower SI than GERD patients for similar acid exposure (P < 0.001). Barrett's patients with abnormal motility had higher acid exposure than those with normal motility (P < 0.05), but the SI values for this group was not significantly different from the GERD patients. SI and Bile reflux in Barrett's esophagus was not significantly different in patients with normal or abnormal motility. Barrett's patients had less sensitivity than GERD patients for similar acid exposure. Normal motility in Barrett's esophagus is associated with the poorest sensitivity and the presence of increased acid exposure is required in order to achieve sensitivity levels comparable with GERD patients.     

Pathophysiology of gastroesophageal reflux diseases in Chinese--role of transient lower esophageal sphincter relaxation and esophageal motor dysfunction

BACKGROUND AND AIMS: Transient lower esophageal sphincter relaxation (TLESR) is the major mechanism for gastroesophageal reflux in the Western population. The major reflux mechanism in Chinese patients with GERD has not been studied before. METHODS: Fifty-four patients with GERD and 28 controls underwent stationary baseline manometry and the 24-h ambulatory esophageal pH monitoring. TLESRs were measured before and after an 850 kcal meal in the supine position. Primary peristalsis, secondary peristalsis, and esophageal acid clearance were measured by esophageal manometry. RESULTS: Total time esophageal pH 相似文献   

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.     

High-resolution manometry of the EGJ: an analysis of crural diaphragm function in GERD

AIM: High-resolution manometry (HRM) provides a spatially enhanced, dynamic representation of the esophagogastric junction (EGJ) high-pressure zone making it possible to isolate the crural diaphragm (CD) contraction from expiratory lower esophageal sphincter (LES) pressure. This study compared CD function of subjects with and without gastroesophageal reflux disease (GERD). METHODS: A total of 75 asymptomatic controls and 156 GERD patients (EGD or pH monitoring positive) underwent HRM. The EGJ axial pressure profile was analyzed over five respiratory cycles to quantify the position and contractile vigor of the CD relative to the LES. Correlations between EGJ HRM attributes and GERD status were examined. RESULTS: GERD patients had significantly greater CD-LES separation compared with either controls or EGD-/pH- patients. GERD patients also had significantly less inspiratory augmentation of EGJ pressure (EGD-/pH+, 11.5 +/- 1.9 mmHg; EGD+, 10.0 +/- 1.2 mmHg) compared with controls (16.9 +/- 1 mmHg) or EGD-/pH- patients (16.7 +/- 0.2 mmHg). Using a logistic regression model that simultaneously examined expiratory LES pressure, LES-CD separation, and inspiratory EGJ augmentation while controlling for age and BMI, only inspiratory augmentation had a significant independent association with GERD. CONCLUSIONS: HRM characterization of EGJ morphology correlates with the objective demonstration of GERD. Although both LES pressure and LES-CD separation are associated with GERD, the strongest association and the only independent predictor of GERD as a categorical outcome in a logistic regression analysis was impaired CD function as indicated by reduced inspiratory augmentation of EGJ pressure.     

胃食管反流病患者酸反流与食管运动功能障碍的关系

背景：异常酸反流和食管运动功能障碍与胃食管反流病（GERD）密切相关。目的：研究GERD患者的食管运动和酸反流与食管黏膜损害的关系，以及两者之间的相关性。方法：选取有反酸、烧心、胸痛等典型胃食管反流症状的患者72例行上消化道内镜检查、食管测压和24hpH监测。根据pH〈4总时间百分比〈4．5％且DeMeester计分〈14．7的标准。将食管炎患者分为生理性酸反流组（pH^-组）和病理性酸反流组（pH^＋组）。结果：内镜下食管炎组24hpH监测各项指标较无食管炎组显著增高（P〈0．05），病理性酸反流的发生率显著高于无食管炎组（P〈0．01）。两组食管测压各项指标无显著差异，食管炎组pH^＋者的食管下括约肌压力（LESP）较pH^-者显著降低，食管体部蠕动波传导速度减慢，湿咽成功率减少（P〈0．05）。结论：GERD患者食管炎的发生与酸反流密切相关，有病理性酸反流的GERD患者易见食管运动功能障碍。     

Endoscopic aspects in diagnosis of gastroesophageal reflux disease and motility disorders: Bravo,capsule, and functional lumen imaging probe

Catheter-based testing remains the current standard of practice for the diagnosis of gastroesophageal reflux disease and esophageal motility abnormalities. Ambulatory pH testing and esophageal manometry have been in use for the past 40 years, but with the development of high-resolution manometry and multichannel intraluminal impedance testing, catheter-based testing has undergone significant recent technological improvement. Nonetheless, these tests continue to have limitations. In the case of ambulatory reflux testing, patient discomfort and limited activity remain significant problems. For esophageal manometry, methodological issues limit its ability to evaluate the function of the esophagogastric junction in normal and diseased states. In recent years, several new diagnostic tools have been developed to address the shortcomings of catheter-based testing. The wireless pH probe has been available for clinical use for more than 10 years, is better tolerated than catheter-based testing, and provides longer monitoring periods. Esophageal capsule endoscopy has undergone clinical evaluation for gastroesophageal reflux disease and Barrett esophagus with mixed results. Functional lumen imaging probe testing is a new technology that is still undergoing clinical evaluation but holds promise as a complimentary method for evaluating esophageal physiology, in particular esophagogastric junction function.     

The relationship between ineffective esophageal motility and gastro-esophageal reflux disease]

BACKGROUND/AIMS: Ineffective esophageal motility (IEM) is a distinct manometric entity characterized by a hypocontractile esophagus. Recently, IEM replaced the nonspecific esophageal motility disorder (NEMD), and its associations with gastro-esophageal reflux disease (GERD) and respiratory symptoms are well known. We evaluated the relationship of IEM with GERD, and the diagnostic value of IEM for GERD. METHODS: We retrospectively analyzed recent 3-year (Jan. 1998-Sep. 2002) datas of esophageal manometry, acid perfusion test and simultaneous 24 hr-ambulatory pH-metry with manometry studies in 270 consecutive patients with esophageal and/or GERD symptoms. The prevalence of IEM in GERD group and non-GERD group, and the variables of pH-metry and manometry among esophageal motility disorders were compared. In addition, the sensitivity, specificity, positive predictive value, negative predictive value of IEM, esophageal symptom, and acid perfusion test for GERD were calculated. RESULTS: There was no significant difference in IEM prevalence rate between GERD group and non-GERD group. In addition, there was no significant difference in GERD prevalence rate and esophageal acid clearance in variety of motility disorder groups. Total percent time of pH <4 in IEM group did not show any difference when compared with other groups except in the achalasia group. In regard of diagnostic value to detect GERD, all positive results showed high specificity (97%) in IEM with esophageal symptom and positive acid perfusion test. CONCLUSIONS: The diagnosis of IEM using esophageal manometry in patients with various esophageal symptoms does not strongly suggest on association with GERD. However, IEM with concomitant esophageal symptoms and positive acid perfusion test has diagnostic values for GERD.     

Clinical Applications of Esophageal Impedance Monitoring and High-Resolution Manometry

Esophageal impedance monitoring and high-resolution manometry (HRM) are useful tools in the diagnostic work-up of patients with upper gastrointestinal complaints. Impedance monitoring increases the diagnostic yield for gastroesophageal reflux disease in adults and children and has become the gold standard in the diagnostic work-up of reflux symptoms. Its role in the work-up for belching disorders and rumination seems promising. HRM is superior to other diagnostic tools for the evaluation of achalasia and contributes to a more specific classification of esophageal disorders in patients with non-obstructive dysphagia. The role of HRM in patients with dysphagia after laparoscopic placement of an adjustable gastric band seems promising. Future studies will further determine the clinical implications of the new insights which have been acquired with these techniques. This review aims to describe the clinical applications of impedance monitoring and HRM.     

Laryngopharyngeal reflux in patients with symptoms of gastroesophageal reflux disease

Laryngopharyngeal reflux (LPR) has been extensively studied in patients with laryngeal signs and symptoms, gastroesophageal reflux being identified in approximately 50%. Few studies have investigated the incidence and significance of LPR in GERD patients. Two-hundred and seventy-six consecutive patients referred with symptoms of gastroesophageal reflux had dual probe 24 h pH, esophageal manometry, GERD and ENT questionnaires. LPR was defined as at least three pharyngeal reflux events less than pH 5.0 with corresponding esophageal reflux, but excluding meal periods. Fourty-two percent of patients were positive for LPR on 24 h pH monitoring and 91.3% corresponded with an abnormal esophageal acid score. Distal esophageal acid exposure was significantly greater (P < 0.001) in patients with LPR but symptoms of GERD and regurgitation scores showed no significant differences between patients with positive and negative LPR on 24 h pH. There was no significant difference between the incidence of LPR in patients with or without laryngeal symptoms. There is a high incidence of LPR in patients with GERD but its significance for laryngeal symptoms is tenuous. Fixed distance dual probe pH monitoring allows documentation of conventional esophageal reflux and LPR.     

High-resolution manometry and impedance-pH/manometry: valuable tools in clinical and investigational esophagology

Both high-resolution manometry (HRM) and impedance-pH/manometry monitoring have established themselves as research tools and both are now emerging in the clinical arena. Solid-state HRM capable of simultaneously monitoring the entire pressure profile from the pharynx to the stomach along with pressure topography plotting represents an evolution in esophageal manometry. Two strengths of HRM with pressure topography plots compared with conventional manometric recordings are (1) accurately delineating and tracking the movement of functionally defined contractile elements of the esophagus and its sphincters, and (2) easily distinguishing between luminal pressurization attributable to spastic contractions and that resultant from a trapped bolus in a dysfunctional esophagus. Making these distinctions objectifies the identification of achalasia, distal esophageal spasm, functional obstruction, and subtypes thereof. Ambulatory intraluminal impedance pH monitoring has opened our eyes to the trafficking of much more than acid reflux through the esophageal lumen. It is clear that acid reflux as identified by a conventional pH electrode represents only a subset of reflux events with many more reflux episodes being composed of less acidic and gaseous mixtures. This has prompted many investigations into the genesis of refractory reflux symptoms. However, with both technologies, the challenge has been to make sense of the vastly expanded datasets. At the very least, HRM is a major technological tweak on conventional manometry, and impedance pH monitoring yields information above and beyond that gained from conventional pH monitoring studies. Ultimately, however, both technologies will be strengthened as outcome studies evaluating their utilization become available.     

Is ineffective esophageal motility gastropharyngeal reflux disease？

AIM： TO evaluate the association between IEM and gastropharyngeal reflux disease （GPRD） in patients who underwent ambulatory 24-h dual-probe pH monitoring for the evaluation of supraesophageal symptoms.
METHODS： A total of 632 patients who underwent endoscopy, esophageal manometry and ambulatory 24-h dual-pH monitoring due to supraesophageal symptoms （e.g. globus, hoarseness, or cough） were enrolled. Of them, we selected the patients who had normal esophageal motility and IEM. The endoscopy and ambulatory pH monitoring findings were compared between the two groups.
RESULTS;： A total of 264 patients with normal esophageal motility and 195 patients with the diagnosis of IEM were included in this study. There was no difference in the frequency of reflux esophagitis and hiatal hernia between the two groups. All the variables showing gastroesophageal reflux and gastropharyngeal reflux were not different between the two groups. The frequency of GERD and GPRD, as defined by ambulatory pH monitoring, was not different between the two groups.
CONCLUSION： There was no association between IEM and GPRD as well as between IEM and GERD. IEM alone cannot be considered as a definitive marker for reflux disease.     

The prevalence of gastroesophageal reflux in asthma patients without reflux symptoms

Gastroesophageal reflux is a potential trigger of asthma that may be clinically silent. This study examines the prevalence of gastroesophageal reflux in asthma patients without reflux symptoms. This prospective cohort study evaluated 26 patients with stable asthma without reflux symptoms using esophageal manometry and 24-h esophageal pH testing. Gastroesophageal reflux was considered present if esophageal acid contact times were abnormal. Demographic variables were analyzed to determine if they predicted the presence of gastroesophageal reflux. Asthma patients with asymptomatic gastroesophageal reflux were compared with 30 age-matched asthma patients with symptomatic gastroesophageal reflux. The prevalence of abnormal 24-h esophageal pH tests in asthma patients without reflux symptoms was 62% (16 of 26). Demographic variables did not predict abnormal 24-h esophageal pH tests in asthma patients with asymptomatic gastroesophageal reflux. Asthma patients with asymptomatic gastroesophageal reflux had higher amounts of proximal esophageal acid exposure (p < 0.05) compared with asthma patients with symptomatic gastroesophageal reflux. Because demographic variables do not predict abnormal 24-h esophageal pH tests in asthma patients without reflux symptoms, 24-h esophageal pH testing is required. This study suggests that gastroesophageal reflux is present in asthma patients, even in the absence of esophageal symptoms.     

Esophageal motor disorders in subjects with incidentally discovered Chagas disease: a study using high‐resolution manometry and the Chicago classification

In patients with chronic indeterminate Chagas disease, conventional manometry has shown that 25–48% had esophageal motor disorders. Recently, esophageal high‐resolution manometry (HRM) has revolutionized the assessment of esophageal motor function. In this study, we performed esophageal HRM in a group of subjects with incidentally positive serological findings for Trypanosoma cruzi. In this prospective observational study, we evaluated subjects who had positive serological tests for Chagas disease detected during a screening evaluation for blood donation. All subjects underwent symptomatic evaluation and esophageal HRM with a 36 solid‐state catheter. Esophageal abnormalities were classified using the Chicago classification. Forty‐two healthy subjects (38 males) aged 18–61 years (mean age, 40.7 years) were included. When specific symptoms questionnaire was applied, 14 (33%) subjects had esophageal symptoms. Esophageal high‐resolution manometry revealed that 28 (66%) of the subjects had an esophageal motility disorder according to the Chicago classification. Most common findings were hypocontractile disorders in 18 subjects (43%) and esophagogastric junction (EGJ) outflow obstruction in 6 (15%). Esophageal high‐resolution manometry reveals that up to two thirds of the subjects with an incidental diagnosis of Chagas disease have esophageal abnormalities. This technology increases the detection and allows a more complete assessment of esophageal motor function in subjects infected with T. cruzi even in the early stages of the disease.     

高分辨率食管测压下胃食管反流病吞咽延迟时间与食管动力的相关性研究

目的探讨高分辨率食管测压（HRM）下胃食管反流病（GERD）患者吞咽延迟时间（DL）与食管动力的关系。方法51例行HRM且24h食管pH监测诊断为GERD的患者根据HRM结果是否存在食管异常蠕动分成动力异常组（n=28）和阴性组（n=23）,另选择14例非GERD者行HRM作为对照（对照组）,统计分析各组HRM监测结果。结果动力异常组DL（7．27±1．44）S明显高于阴性组的（6．704±41）S和对照组的（5．86±0．96）2,差异均有统计学意义（P〈0．01）,且阴性组也明显高于对照组（P〈0．01）;动力异常组的远端收缩积分（712．49±703．10）mmHg·s·cm明显低于阴性组的（1285．85±850．83）mmHg·s·cm和对照组的（1109．74±611．70）mmHg·s·cm,差异均有统计学意义（P〈0．01）,而阴性组与对照组比较差异无统计学意义（P〉0．05）;各组间食管下括约肌压力、收缩前沿速度及食管下括约肌处食团内部压力差异均无统计学意义（P〉0．05）。结论HRM下DL的延长与GERD患者食管蠕动减弱明显相关,GERD患者表现为更长的DL,证明食管动力的改变是GERD发生发展的重要环节。