Diagnostic Accuracy of EndoFaster® and Narrow-Band Imaging Endoscopy in Patients with Impaired Gastric Acid Secretion: A Real-Time Prospective Study

Gastric juice analysis in clinical practice: why, how, and when. The experience with EndoFaster

Gastric juice analysis may be useful for clinical purposes, including the detection of H. pylori infection and diffuse atrophic gastritis on gastric mucosa. EndoFaster is a novel device which performs real-time analysis of gastric juice revealing the infection and hypochlorhydria by measuring ammonium concentrations and pH levels. This review aimed to evaluate the clinical applications of such a tool. By considering data from overall 11 studies, the values of sensitivity, specificity, positive predictive value, negative predictive value, accuracy, positive likelihood ratio, and negative likelihood ratio were 90%, 86%, 67%, 96%, 87%, 8.5, and 0.13, respectively, for H. pylori diagnosis, and 83%, 92%, 58%, 97%, 91%, 9.9 and 0.2, respectively, for suspecting diffuse atrophic gastritis. The very high value of negative predictive values for both H. pylori and mucosal atrophy would allow avoiding to perform useless negative gastric biopsies when the results of the test are negative. Some promising data suggest that gastric juice analysis may be useful also to diagnose H. pylori infection in patients with chronic active gastritis without evidence of bacteria at histology, as well as in predicting persistent acid reflux in patients on proton pump inhibitor therapy for reflux disease.

Real-time assessment of H. pylori during the endoscopic assessment of individuals with gastric intestinal metaplasia: a possible way to reduce the burden of care

OBJECTIVES

The management of individuals with gastric intestinal metaplasia (GIM) includes biopsies for its staging and to diagnose Helicobacter pylori (Hp ). Advanced-stage GIM can be estimated by endoscopy through EGGIM, and a new device permits the real-time assessment of ammonia for the identification of Hp infection. The aim of this study was to assess the simultaneous use of EGGIM and real-time assessment of ammonia to avoid biopsies and reduce the burden of care in clinical practice.

METHODS

A multicentre study involving 101 consecutively enrolled patients [52% male; 65(18-85) years]. During endoscopy, gastric juice was aspirated and analysed; EGGIM was determined in real-time. Targeted biopsies were performed and histopathological assessment was used as gold standard.

RESULTS

Advanced-stage GIM were detected in 14.9% of patients and Hp infection in 18.8%. EGGIM showed for advanced-stage GIM a sensitivity, specificity and NPV of 86.7%, 84.9% and 97.3%, whilst real-time assessment of ammonia, 83.3%, 78.2% and 95.4%, respectively. Gastric juice was insufficient in 5 (5.0%). Overall, 64 (67%) patients were correctly diagnosed by EGGIM and real-time assessment of ammonia. If the 47 (49%) patients negative to both assessments would have avoided biopsies, only 4 (4.2%) would have been missed: two with advanced-stage GIM and two with Hp infection.

CONCLUSION

The combination of endoscopic assessment and real-time analysis of Hp allows the exclusion of advanced-stage GIM or Hp infection without the need of biopsies in a significant proportion of individuals. This may allow in specific situations to abstain from biopsies reducing the burden of care.

Linking dysbiosis to precancerous stomach through inflammation: Deeper than and beyond imaging

Upper gastrointestinal endoscopy is considered the gold standard for gastric lesions detection and surveillance, but it is still associated with a non-negligible rate of missing conditions. In the Era of Personalized Medicine, biomarkers could be the key to overcome missed lesions or to better predict recurrence, pushing the frontier of endoscopy to functional endoscopy. In the last decade, microbiota in gastric cancer has been extensively explored, with gastric carcinogenesis being associated with progressive dysbiosis. Helicobacter pylori infection has been considered the main causative agent of gastritis due to its interference in disrupting the acidic environment of the stomach through inflammatory mediators. Thus, does inflammation bridge the gap between gastric dysbiosis and the gastric carcinogenesis cascade and could the microbiota-inflammation axis-derived biomarkers be the answer to the unmet challenge of functional upper endoscopy? To address this question, in this review, the available evidence on the role of gastric dysbiosis and chronic inflammation in precancerous conditions of the stomach is summarized, particularly targeting the nuclear factor-κB (NF-κB), toll-like receptors (TLRs) and cyclooxygenase-2 (COX-2) pathways. Additionally, the potential of liquid biopsies as a non-invasive source and the clinical utility of studied biomarkers is also explored. Overall, and although most studies offer a mechanistic perspective linking a strong proinflammatory Th1 cell response associated with, but not limited to, chronic infection with Helicobacter pylori, promising data recently published highlights not only the diagnostic value of microbial biomarkers but also the potential of gastric juice as a liquid biopsy pushing forward the concept of functional endoscopy and personalized care in gastric cancer early diagnosis and surveillance.

Real-time determination of gastric juice pH with EndoFaster® for atrophic gastritis assessment

BACKGROUND

In patients with atrophic gastritis involving gastric body mucosa the pH value of gastric juice is distinctly increased, so that pH assessment would allow predict this precancerous lesion. We tested whether EndoFaster® - a device allowing real-time pH measure and H. pylori diagnosis - may optimize the need of taking gastric biopsies.

METHODS

In this prospective, multicentre study, the accuracy of EndoFaster® for ruling out gastric atrophy involving corporal mucosa was assessed. Real-time pH and ammonium determination was performed by aspirating 3-6 ml gastric juice during endoscopy. Histology performed on 5 standard gastric biopsies was used as gold standard.

RESULTS

A total of 1008 consecutive patients were observed in 12 centres. At histology, gastric body mucosa atrophy/metaplasia was detected in 65 (6.4%) cases, and a pH value >4.5 in the gastric juice was observed in 150 patients. The values of EndoFaster® performance in predicting the presence of atrophic gastritis were as follow: 51% sensitivity, 84% specificity, 18% PPV, 96% NPV, and 82% accuracy. The NPV value was not distinctly affected by neither ongoing proton pump inhibitor therapy nor H. pylori infection. By considering also data of ammonium concentrations, the values of EndoFaster® in detecting extensive atrophy on gastric mucosa were 74% sensitivity, 84% specificity, 24% PPV, 98% NPV, and 83% accuracy.

CONCLUSION

The very high NPV of EndoFaster® might allow to safely rule out presence of atrophic gastritis, reducing the need of taking gastric biopsies in unselected patients managed in clinical practice.

Real-time gastric juice analysis with EndoFaster for H. pylori diagnosis: a large, multicentre study

BACKGROUND

Helicobacter pylori infection is the main cause of the most frequent gastroduodenal diseases. Because its prevalence is decreasing in developed countries, gastric biopsies are negative in several patients. By measuring ammonium in the gastric juice, EndoFaster allows to exclude H. pylori infection during endoscopy. This study aimed to assess the accuracy of device versions working with either 6 ml or 3 ml of gastric juice.

STUDY DESIGN

This prospective study involved 12 endoscopic units. During endoscopy, EndoFaster testing was performed and standard five gastric biopsies were taken. The accuracy was calculated by considering histological assessment as the gold standard for H. pylori diagnosis.

RESULTS

Gastric juice analysis was attempted in 1279 patients, but it failed in 131 (15.5%) and in 10 (2.3%), with the 6 ml and the 3 ml device, respectively (P < 0.001). Overall, EndoFaster detected H. pylori infection with an 86.3% sensitivity, 83.3% specificity, 52.7% positive predictive value, 96.6% negative predictive value and 83.8% accuracy. The performance was not affected either by ongoing proton pump inhibitor therapy or a previous H. pylori eradication. No significant difference in accuracy emerged between the two versions of the device.

CONCLUSION

The novel version of the EndoFaster device operating with 3 ml gastric juice may be performed in virtually all patients, and it allows excluding H. pylori infection with a very high accuracy. Gastric biopsies can be avoided in a definite portion of cases without endoscopic lesions or other clinical indications.

Gastric epithelial histology and precancerous conditions

The most common histological type of gastric cancer (GC) is gastric adenocarcinoma arising from the gastric epithelium. Less common variants include mesenchymal, lymphoproliferative and neuroendocrine neoplasms. The Lauren scheme classifies GC into intestinal type, diffuse type and mixed type. The WHO classification includes papillary, tubular, mucinous, poorly cohesive and mixed GC. Chronic atrophic gastritis (CAG) and intestinal metaplasia are recommended as common precancerous conditions. No definite precancerous condition of diffuse/poorly/undifferentiated type is recommended. Chronic superficial inflammation and hyperplasia of foveolar cells may be the focus. Presently, the management of early GC and precancerous conditions mainly relies on endoscopy including diagnosis, treatment and surveillance. Management of precancerous conditions promotes the early detection and treatment of early GC, and even prevent the occurrence of GC. In the review, precancerous conditions including CAG, metaplasia, foveolar hyperplasia and gastric hyperplastic polyps derived from the gastric epithelium have been concluded, based on the overview of gastric epithelial histological organization and its renewal.