The validity of I-Scan in diagnosis of gastroesophageal reflux disease

Abstract

Background: The evaluation of patients with suspected gastroesophageal reflux disease (GERD) frequently represents a diagnostic dilemma. Confirmation of the presence of the esophogeal mucosal injury is one of the roles of endoscopy in GERD diagnosis. In this context, there are limitations of white light endoscopy (WLE) because of the inadequate visualization of the minute mucosal changes and the uncertainty in describing the severity of mucosal injury. I-SCAN technology helps in revealing fine details of the GI mucosa. Aim: to evaluate the diagnostic efficacy of I-SCAN technology as compared to white light endoscopy (WLE) in Egyptian patients suffering from GERD symptoms. Patients and methods: This study included adult patients with GERD questionnaire (Q) score ≥ 8 points. The distal esophagus was examined by WLE followed by I-SCAN 2 to evaluate the presence of mucosal injuries and to classify GERD severity according to the Los Angles (LA) classification & its Japanese modification, respectively. Biopsies were taken from the lower esophageal mucosa as well as from the visible mucosal breaks and subjected to histopathologic examination. Results: Sixty patients were enrolled; 32 (53.3%) were females & 28 (46.7%) were males. WLE showed erosive reflux disease (ERD) in 41 patients (68.3%); while 19 patients (31.7%) showed no mucosal breaks. As regard LA classification; 18 of the cases were classified as grade A (30%); 15 as grade B (25%); 7 as grade C (11.7%) and 1 as grade D (1.7%). Reexamination of distal esophagus by I-SCAN 2 showed minimal change esophagitis (MCE) (grade M) & ERD in 57 patients (95%); while only 3 patients (5%) showed no mucosal changes (grade N). As regard the modified LA classification; 16 cases were classified as grade M (26.6%); 12 as grade A (20%); 21 as grade B (35%); 7 as grade C (11.7%) and 1 as grade D (1.7%). There was perfect agreement of WLE with I-SCAN 2 in LA grades B, C & D. There was poor agreement of WLE with I-SCAN 2 in cases who had no mucosal breaks & LA grade A cases on WLE (weighted Kappa was 0.11); as 16 cases were reclassified as grade M on I-SCAN 2 (had no mucosal breaks on WLE) and 6 cases were reclassified as class B on I-SCAN 2(were classified as grade A on WLE). As regard the histological proven reflux esophagitis (HPRE), it was present in 41 (68.3%) of the studied cases with statistically significant higher proportion of male gender. It was present in 28 (68.3%) of the patients who had ERD on WLE; 13(68.4%) of the patients who had no mucosal breaks on WLE; 38 (66.6%) of the cases who had grade M or ERD on I-SCAN 2 & the three patients who had grade N on I-SCAN 2.GERD Q score ranged from 10 to 12 points with median of 11 points. It was significantly higher in patients with HPRE (11.4 ± 1.8 points) than those without (10.3 ± 1.3 points) (p= 0.026). GERD Q score strongly correlated with both the modified LA grade by I-SCAN 2 (p=0.03) and the histological severity score (p=0,016). On univariate & multivariate analysis, male gender and GERD Q score > 11points were significant predictors of HPRE (p < .001). ROC analysis curve showed that GERD Q score at a cut-off > 11points was a significant predictor of HPRE with a sensitivity of 47%, specificity of 85%, AUC of 66.7% and p = 0.015. Conclusion: I-SCAN technology may improve the diagnosis of the esophogeal mucosal injury in GERD patients. There was poor agreement of WLE with I-SCAN 2 in patients who had no mucosal breaks & those with LA grade A on WLE. However, there was perfect agreement of WLE with I-SCAN 2 in patients with LA grades B, C& D. GERD Q score had positive correlation with both the modified LA grade on I-SCAN 2 and the histological severity score. Male gender and GERD Q score > 11points were significant predictors of histological proven reflux esophagitis.