Mean Nocturnal Baseline Impedance Correlates With Symptom Outcome When Acid Exposure Time Is Inconclusive on Esophageal Reflux Monitoring.

BACKGROUND & AIMS: Abnormal acid exposure time (AET) is associated with good outcomes of symptoms from antireflux therapy. Low esophageal mean nocturnal baseline impedance (MNBI) is an additional marker of reflux disease. We aimed to evaluate the value of MNBI when analysis of AET produces borderline or inconclusive results. METHODS: We studied a retrospective cohort of 371 patients (mean age, 54.5 ± 0.7 y; 60.0% female) who had persistent reflux symptoms after treatment and underwent ambulatory pH-impedance monitoring off antisecretory therapy at 1 tertiary center in Europe or 1 in the United States. Total AET was determined from pH impedance studies (pathologic, >6%; physiologic, <4%; borderline or inconclusive, 4%-6%). Baseline impedance values were calculated at the 5-cm impedance channel at 3 nocturnal 10-minute periods and averaged to yield MNBI (abnormal, <2292 ohms). The primary outcome was response to antireflux therapy, defined as global symptom improvement of 50% or greater on patients' answers on standardized visual analog scales. RESULTS: Among the 371 patients, 107 (28.8%) had pathologic AET and 234 (63.1%) had abnormal MNBI. Low MNBI was concordant in 99.1% of patients with pathologic AET, in 91.2% with borderline AET, and in 33.7% with physiologic AET. During 38.7 ± 0.8 months of follow-up evaluation, 43.0% of patients had improved symptoms with medical therapy and 76.2% had improved symptoms with surgical antireflux therapy (P < .0001). When MNBI was low, response to medical therapy did not differ significantly between patients with borderline AET and patients with pathologic AET (P = .44), but did differ significantly when each group was compared with patients with physiologic AET, regardless of whether MNBI was normal or low (P < .0001 for each comparison). CONCLUSIONS: When low, MNBI identifies patients with pathologic and borderline AET who respond to antireflux therapy. MNBI analysis complements AET in defining esophageal reflux burden. MNBI correlates with response of symptoms to antireflux therapy.

Correlation between reflux burden, peristaltic function, and mucosal integrity in GERD patients.

BACKGROUND: Mean nocturnal baseline impedance (MNBI) augments the diagnostic yield of multichannel intraluminal impedance-pH (MII-pH) monitoring. While acid exposure time (AET) correlates with MNBI, it remains unclear whether esophageal motility affects MNBI values. The present study was aimed at evaluating the respective roles of esophageal motor function and AET on MNBI. METHODS: High-resolution manometry (HRM) studies and ambulatory 24-hour MII-pH monitoring tracings were retrospectively analyzed from consecutive endoscopy-negative GERD patients with typical symptoms responsive to previous acid-suppressive therapy from three tertiary care centers. Univariate and multivariate analyses were performed to determine predictors of pathologic MNBI values at 3 cm and 5 cm above the lower esophageal sphincter (LES). KEY RESULTS: Patients with pathological AET displayed lower MNBI values at 3 cm and 5 cm (P < .01) compared to patients with non-pathological AET. Similarly, significantly lower MNBI values were also noted at both sites with type 3 EGJ compared to type 1 EGJ (P ≤ .02 for each comparison), and with absent contractility compared to normal peristalsis (P ≤ .02 for each comparison). On multivariate analysis, the presence of type 2 or 3 EGJ and absent contractility were associated with a significantly higher probability of pathological MNBI values at 3 cm and 5 cm above the LES. CONCLUSIONS AND INFERENCES: Disruption of the EGJ and absent contractility on HRM are both associated with lower MNBI values. HRM findings complement reflux testing using MII-pH monitoring.

Updates in the field of non-esophageal gastroesophageal reflux disorder.

Introduction: Gastroesophageal reflux disease (GERD) is one of the most prevalent conditions in Western Countries, normally presenting with heartburn and regurgitation. Extra-esophageal (EE) GERD manifestations, such as asthma, laryngitis, chronic cough and dental erosion, represent the most challenging aspects from diagnostic and therapeutic points of view because of their multifactorial pathogenesis and low response to proton pump inhibitors (PPIs). In fact, in the case of EE, other causes must by preventively excluded, but instrumental methods, such as upper gastrointestinal endoscopy and laryngoscopy, have low specificity and sensitivity as diagnostic tools. In the absence of alarm signs and symptoms, empirical therapy with a double-dose of PPIs is recommended as a first diagnostic approach. Subsequently, impedance-pH monitoring could help to define whether the symptoms are GERD-related. Areas covered: This article reviews the current literature regarding established and proposed EE-GERD, reporting on all available options for its correct diagnosis and therapeutic management. Expert opinion: MII-pH could help to identify a hidden GERD that causes EE. Unfortunately, standard MII-pH analysis results are often unable to define this association. New parameters such as the mean nocturnal baseline impedance and post-reflux swallow-induced peristaltic wave index may have an improved diagnostic yield, but prospective studies using impedance-pH are needed.

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

INTRODUCTION: 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.

A safety review of proton pump inhibitors to treat acid-related digestive diseases.

INTRODUCTION: Proton pump inhibitors (PPIs) have become the first choice medical treatment of acid-related disease and, as with any pharmacological agent, they have been reported to be associated with some adverse events mainly linked to their chronic use. The most important postulated harms are represented by serum electrolyte alterations, vitamin B12 and iron deficiency, gastric tumors, enteric infections, spontaneous bacterial peritonitis, pneumonia, ischemic heart attacks, bone fractures, chronic kidney disease, dementia, and Alzheimer disease. Specific pathophysiological mechanisms have been identified for some of them and not for other manifestations. AREAS COVERED: However, studies on PPIs safety have generally important limitations because of their frequent retrospective design and other methodological drawbacks, such as patients' selection and residual confounders. EXPERT OPINION: Obviously, in the vast majority of the cases, adverse drug reactions cannot be assessed by means of randomized clinical trials due to the high costs, ethical reasons, and difficulties in performing prospective observational studies. So far, assessment of retrospective observational investigations remains the only method to evaluate adverse events with any drug in general and, although the weaknesses of these studies are evident, the awareness of the reported associations with the medications analyzed is important for physicians in order to manage adequately their individual patients.

A review of pharmacotherapy for treating gastroesophageal reflux disease (GERD).

INTRODUCTION: Medical therapy of gastroesophageal reflux disease (GERD) is based on the use of proton pump inhibitors (PPIs) as first choice treatment. Despite their effectiveness, about 20-30% of patients report an inadequate response and alternative drugs are required. Areas covered: This review provides an overview of current pharmacotherapy for treating GERD by showing the results of PPIs, reflux inhibitors, antidepressants and mucosa protective medications. Expert opinion: Medical therapy of GERD does not definitely cure the disease, because even PPIs are not able to change the key factors responsible for it. However, they remain the mainstay of medical treatment, allowing us to alleviate symptoms, heal esophagitis and prevent complications in the majority of cases. Nevertheless, many patients do not respond, because acid does not play any pathogenetic role. Prokinetics and reflux inhibitors have the potential to control motor abnormalities, but the results of clinical trials are inconsistent. Antidepressant drugs are effective in specific subgroups of NERD patients with visceral hypersensitivity, but larger, controlled clinical studies are necessary. Protective drugs or medical devices have been recently adopted to reinforce mucosal resistance and preliminary trials have confirmed their efficacy either combined with or as add-on medication to PPIs in refractory patients.