PP-6 BOLUS CLEARANCE TIME IS ASSOCIATED WITH REFLUX SEVERITY AND IT IS INVERSELY CORRELATED TO BASELINE IMPEDANCE VALUES IN ADOLESCENTS WITH GASTROESOPHAGEAL REFLUX DISEASE.

Aims: The role of esophageal clearance is still scarcely investigated in patients with gastroesophageal reflux disease (GERD). We aimed to assess esophageal clearance in adolescents by means of bolus clearance time (BCT) and to verify if there is any difference among subgroups of GERD patients according to endoscopic and impedance-pH monitoring findings. Methods: We revised endoscopic and impedance-pH monitoring (off-therapy) data of 28 consecutive adolescents (range 12–16 years). We evaluated acid exposure time (AET), total number of reflux episodes, baseline impedance (BI), and BCT. According to impedance-pH monitoring features, adolescents were grouped into pH/MII negative (normal AET and normal number of refluxes), and pH/MII positive (abnormal AET and/or abnormal number of refluxes). This latter were further subgrouped on the basis of abnormal/normal AET (pH+/-) and abnormal/normal number of refluxes (MII+/-). Finally, adolescents were also classified as erosive and non erosive reflux disease (ERD, NERD). Results: We observed 22 pH/MII positive adolescents (7 ERD and 15 NERD). Eight patients were further subgrouped as pH+/MII-, 6 as pH-/MII+ and 8 as pH+/MII+. BCT values (in seconds) progressively decreased from pH+/MII+, pH+/MII-, pH-/MII+ to pH-/MII- (34.5 ± 8.1 vs. 22.0 ± 7.2 vs. 16.4 ± 4.5 vs. 10.1 ± 2.1, respectively; p < 0.001), whereas BI gradually increased (1236 ± 358 vs. 1592 ± 762 vs. 1854 ± 567 vs. 3256 ± 743, respectively; p < 0.001). There was an inverse correlation between BCT and BI, and a direct correlation between BCT and AET (p < 0.0001) and ERD presence (p < 0.0001). Conclusions: BCT seems to reflects reflux severity, and it is inversely correlated to BI, a marker of mucosal integrity, supporting the role of esophageal clearance in the GERD pathophysiology.