Comparison of Esophageal Function Tests in Chinese Patients with Functional Heartburn and Reflux Hypersensitivity

Association between Mean Nocturnal Baseline Impedance (MNBI) and Post-Reflux Swallow-Induced Peristaltic Wave Index (PSPW) in GERD Patients

Gastroesophageal reflux disease (GERD) is one of the most common gastrointestinal disorders in the world. Two parameters, mean nocturnal baseline impedance (MNBI) and post-reflux swallow-induced peristaltic wave index (PSPW), have been recently proposed to help differentiate GERD phenotypes. Our study aimed to assess whether there is any correlation between the two parameters, while also taking a look at their ability to distinguish between GERD phenotypes. We recruited 81 patients who were divided into 4 groups based on their GERD phenotype: erosive reflux disease (ERD), non-erosive reflux disease (NERD), reflux hypersensitivity (RH), and functional heartburn (FH). Both MNBI (AUROC 0.855) and PSPW (AUROC 0.835) had very good performances in separating ERD patients from non-ERD patients. PSPW (AUROC 0.784) was superior to MNBI (AUROC 0.703) in distinguishing NERD patients from patients with RH or FH. The PSPW index (AUROC 0.762) was more effective than MNBI (AUROC 0.668) in separating RH from FH. We found that PSPW and MNBI have a strong statistical correlation (Pearson correlation coefficient, r = 0.722, p < 0.001). Furthermore, PSPW predicted pathological MNBI (<2292 Ω) with good performance (AUROC 0.807). MNBI and PSPW are useful in distinguishing GERD phenotypes, with a strong correlation between the two parameters.

Improved diagnosis of reflux hypersensitivity

BACKGROUND

Reflux hypersensitivity (RH) is characterized by normal esophageal exposure to acid and positive correlation of symptoms to reflux episodes. Positivity of Symptomatic Index (SI) and/or Symptom Association Probability (SAP) is used diagnostically, though experts support that concordance of both is needed. We evaluated differences among patients with RH and concordance of SI/SAP or not.

METHODS

Patients with typical reflux symptoms without previous GERD diagnosis, submitted simultaneously to Ph-Impedance off PPI and high resolution manometry were included. Self-response to PPI was evaluated. Patients showing SI and/or SAP positivity were considered having RH and further classified to definite RH if both SI/SAP were positive or indefinite if only one positive.

KEY RESULTS

Totally 2659 patients (M/F: 35.6%/64.7%, mean age: 45 ± 14) were included. Final diagnosis was; FH: 21.8%, RH: 29.3% (definite: 14.3%/indefinite: 15%), GERD: 36% and inconclusive GERD: 12.9%. Patients with definite RH showed increased total reflux time, total number of reflux episodes and length of hiatus hernia, and also numerically but not statistically significant increased rates of PPI responsiveness versus indefinite RH and decreased mean nocturnal baseline impedance. Moreover, they showed significantly increased rate of PPI response versus patients with functional heartburn (FH).

CONCLUSION & INFERENCES

Some PPI responsiveness is frequent among patients with RH as also with FH, and cannot discriminate those entities clinically when diagnosing RH using SI and/or SAP positive criterion. Patients with RH and SI/SAP concordance differ from patients without. Implementation of a strict RH definition (both SI and SAP positive) can better distinguish RH from FH and should be used in the future.

Mean nocturnal baseline impedance, a novel metric of multichannel intraluminal impedance-pH monitoring in diagnosing gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) is a common disease with increasing prevalence worldwide. However, the diagnosis of GERD is challenging because there are no definite gold standard criteria. Recently, a novel impedance parameter, namely mean nocturnal baseline impedance (MNBI), has been proposed, which reflects the burden of longitudinal reflux and the integrity of esophageal mucosa. MNBI has shown an immense promise for increasing the diagnostic rate of multichannel intraluminal impedance-pH (MII-pH) monitoring and predicting the response to proton pump inhibitor (PPI) or anti-reflux intervention in patients with reflux symptoms. The present paper reviews the association between baseline impedance and esophageal mucosal integrity, the acquisition of MNBI in 24-h MII-pH monitoring, the clinical utilization of MNBI in improving the diagnosis rate of GERD in patients with typical reflux symptoms, predicting the response to PPI or anti-reflux treatment in these patients, the utilization of MNBI in diagnosing patients with atypical symptoms or extra-esophageal symptoms, and the correlation between reflux burden and MNBI. MNBI should be routinely assessed using MII-pH monitoring.

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.

Esophageal Nocturnal Baseline Impedance and Post-reflux Swallow-induced Peristaltic Wave Index in Identifying Proton Pump Inhibitor-refractory Non-erosive Reflux Disease

Background/Aims

Esophageal mean nocturnal baseline impedance (MNBI) levels and post-reflux swallow-induced peristaltic wave (PSPW) index could increase the diagnostic value of 24-hour multichannel intraluminal impedance and pH monitoring in patients with gastroesophageal reflux disease. This study aims to compare the MNBI and PSPW index in patients with no evidence of erosive reflux disease.

Methods

Impedance-pH monitoring tracings from 70 patients, 50 with non-erosive reflux disease (NERD) and 20 with functional heartburn (FH), were reviewed. According to proton pump inhibitors (PPI) treatment response, NERD patients were divided into NERD/PPI responders and NERD/PPI nonresponders. MNBI, PSPW index, and intercellular spaces were measured and compared among each group.

Results

MNBI values and PSPW index were lower in NERD patients than in FH (P < 0.01 and P < 0.05, respectively). MNBI positively correlated with PSPW index (r = 0.525, P < 0.001). NERD/PPI responders had lower MNBI values and PSPW index compared to NERD/PPI nonresponders (both P < 0.01). MNBI and PSPW index distinguished NERD from FH patients with an area under the curve of 0.914 and 0.677, respectively. Wider intercellular space could be identified in patients with NERD (P < 0.01).

Conclusion

MNBI and PSPW index may differentiate NERD from FH patients and relate to PPI treatment efficacy in patients with NERD.

Role of Reflux in the Pathogenesis of Eosinophilic Esophagitis: Comprehensive Appraisal With Off- and On PPI Impedance-pH Monitoring

OBJECTIVES

Role of reflux and mechanisms of response to proton pump inhibitor (PPI) therapy in eosinophilic esophagitis (EoE) have not yet been fully elucidated. Comprehensive assessment by impedance-pH monitoring could clarify these issues.

METHODS

Prospective multicenter study comparing EoE patients with healthy controls and gastroesophageal reflux disease cases. Patients with EoE were evaluated off- and on PPI; responsiveness was assessed by histology. Impedance-pH appraisal included chemical clearance, assessed with the postreflux swallow-induced peristaltic wave (PSPW) index, and mucosal integrity measured with mean nocturnal baseline impedance (MNBI).

RESULTS

Sixty consecutive patients with EoE were compared with 60 age- and sex-matched healthy controls and 60 subjects with gastroesophageal reflux disease. The number of total refluxes was higher, while the PSPW index was lower in patients with EoE than in healthy controls. Off PPI, a lower MNBI gradient between the mid and distal esophagus distinguished 20 patients with PPI-refractory EoE from 40 patients with PPI-responsive EoE and was a predictor of PPI failure. On PPI, a lower PSPW index was the sole reflux parameter distinguishing PPI-refractory from PPI-responsive EoE; all reflux parameters improved in PPI-responsive patients, whereas the PSPW index was not modified in PPI-refractory cases and was independently associated with PPI-responsiveness. MNBI in the distal and mid esophagus improved much more in PPI-responsive than in PPI-refractory EoE.

DISCUSSION

Reflux plays a role in the pathogenesis of EoE, more relevant in PPI-responsive cases. Low impedance gradient between the mid and distal esophagus may be useful to predict PPI refractoriness. PPIs mainly act by improving chemical clearance, i.e., by an antireflux action supporting long-term prescription in PPI-responsive EoE.

Reflux hypersensitivity

Reflux hypersensitivity (RH) is a condition characterized typically by heart burn, normal gastroscopy and esophageal biopsy, normal esophageal pH-impedance test, and a close correlation between heart burn and reflux events. Recently, Rome Ⅳ criteria suggests that reflux hypersensitivity is a new type of esophageal functional disease. It is very common in clinical practice and often coexists with functional heartburn. Diagnosis is based on heartburn symptoms, gastroscopy, esophageal biopsy, esophageal pH-impedance, and high resolution esophageal pressure. RH patients have normal acid exposure, and there is no dynamic disease in esophageal dynamic test. However, there are still some difficulties in the differential diagnosis of esophageal functional diseases. Symptom associated probability cannot reliably distinguish reflux hypersensitivity and functional heartburn. The pathogenesis of RH is not entirely clear. Recent studies have shown that esophageal sensitivity to acid and mucosal integrity can lead to RH. Because more than 90% of patients do not respond to proton pump inhibitors, esophageal neuromodulators, such as tricyclic antidepressants, are the main treatment, but the efficacy is uncertain. Surgery is a desirable method, but the indications should be strictly selected. In the future, it is important to strengthen the research of RH pathogenesis and seek new therapeutic targets.