Optimization of impedance-measured reflux events in GORD utilizing acid exposure time

Updates to the modern diagnosis of GERD: Lyon consensus 2.0

The Lyon Consensus provides conclusive criteria for and against the diagnosis of gastro-oesophageal reflux disease (GERD), and adjunctive metrics that consolidate or refute GERD diagnosis when primary criteria are borderline or inconclusive. An international core and working group was assembled to evaluate research since publication of the original Lyon Consensus, and to vote on statements collaboratively developed to update criteria. The Lyon Consensus 2.0 provides a modern definition of actionable GERD, where evidence from oesophageal testing supports revising, escalating or personalising GERD management for the symptomatic patient. Symptoms that have a high versus low likelihood of relationship to reflux episodes are described. Unproven versus proven GERD define diagnostic strategies and testing options. Patients with no prior GERD evidence (unproven GERD) are studied using prolonged wireless pH monitoring or catheter-based pH or pH-monitoring off antisecretory medication, while patients with conclusive GERD evidence (proven GERD) and persisting symptoms are evaluated using pH-impedance monitoring while on optimised antisecretory therapy. The major changes from the original Lyon Consensus criteria include establishment of Los Angeles grade B oesophagitis as conclusive GERD evidence, description of metrics and thresholds to be used with prolonged wireless pH monitoring, and inclusion of parameters useful in diagnosis of refractory GERD when testing is performed on antisecretory therapy in proven GERD. Criteria that have not performed well in the diagnosis of actionable GERD have been retired. Personalisation of investigation and management to each patient's unique presentation will optimise GERD diagnosis and management.

Role of the Mean Nocturnal Baseline Impedance in Identifying Evidence Against Pathologic Reflux in Patients With Refractory Gastroesophageal Reflux Disease Symptoms as Classified by the Lyon Consensus

Background/Aims

Mean nocturnal baseline impedance (MNBI) is a new reflux metric for mucosal integrity. It remains unclear whether MNBI can help identify evidence against pathological reflux by the Lyon Consensus in patients with refractory gastroesophageal reflux disease (GERD) symptoms.

Methods

Three hundred and forty-nine patients with refractory GERD symptoms enrolled in this study were subjected to high-resolution manometry, 24-hour multichannel intraluminal impedance-pH (MII-pH) monitoring, and endoscopy. Conventional indexes (ie, reflux events and acid exposure time) and the novel index (MNBI) of MII-pH monitoring were extracted and analyzed. The value of MNBI in diagnosing patients with evidence against pathologic reflux was evaluated by receiver-operating-characteristic analysis.

Results

There were 102 (29.2%) patients with evidence against pathologic reflux, 149 (42.7%) with inconclusive or borderline evidence and 98 (28.1%) with conclusive evidence for pathologic reflux. The MNBI was significantly higher while the proportion of pathological MNBI was significantly lower in subjects with evidence against pathologic reflux than in patients with inconclusive or borderline evidence and in patients with conclusive evidence for pathologic reflux (2444.3 [1977.9-2997.4] vs 1992.8 [1615.5-2253.6] and vs 1772.3 [758.6-2161.3], both P < 0.001; 42.2% vs 79.7% and vs 80.0%, both P < 0.05). When identifying evidence against pathologic reflux in patients with refractory GERD symptoms, the MNBI yielded an area under the curve of 0.749 (P < 0.001) at a cutoff value of 1941.8 Ω.

Conclusions

The MNBI has a good diagnostic value for evidence against pathological reflux in patients with refractory GERD symptoms. For its simplicity and reproducibility, we believe that MNBI should be referred to in reports of impedance-pH tracings by physicians.

Normal acid exposure time in esophageal pH monitoring in Asian and Western populations: A systematic review and meta-analysis

BACKGROUND

Esophageal acid exposure time (AET) during 24 h pH monitoring is reproducible and predictive outcomes of treatment for gastroesophageal reflux disease. Several small Asian studies have investigated the normal range of the AET; the range may be different from that in Western populations. We evaluated its normal range in healthy Asian compared to Western subjects.

METHODS

We searched PubMed, Embase, Cochrane Library, and KoreaMed for studies that reported pH monitoring parameters in healthy subjects. Studies that reported the AET values of healthy subjects were eligible for the analyses. The upper limit of normal of the AET was obtained from the 95th percentile of the available raw data or calculated as the mean value +2 standard deviations.

KEY RESULTS

Nineteen Asian and 49 Western studies were assessed. The estimated AET values were analyzed using a bootstrapping technique, weighted according to the sample size. The mean AET was 1.1% and 2.9% in the Asian and Western populations, respectively. The upper limit of the reference range was 3.2% (95% confidence interval [CI], 2.7-3.9%) and 8.2 (95% CI, 6.7-9.9) in the Asian and Western populations, respectively. The normal AET differed between the Asian and Western populations because the CI of the two groups did not overlap.

CONCLUSIONS & INFERENCES

The upper limit of normal of the AET in healthy Asian subjects was 3.2% (95% CI, 2.7-3.9%), which was lower than that of healthy Western subjects.