719 REDUCED MEAN NOCTURNAL BASELINE IMPEDANCE AIDS DIAGNOSIS OF GASTRO-ESOPHAGEAL REFLUX DISEASE AND LARYNGOPHARYNGEAL REFLUX DISEASE

Laryngopharyngeal reflux disease (LPR) and gastro-esophageal reflux disease (GERD) occur due to acidic gastric refluxate causing symptoms. Baseline esophageal impedance has been shown to be reduced with prolonged acid exposure. Mean nocturnal baseline impedance (MNBI) is a novel measure that has shown promise in GERD but has not been evaluated in LPR. This study aimed to assess the role of MNBI in LPR and GERD patients. Methods Off-therapy impedance-pH tracings were blindly reviewed for 187 patients previously prospectively allocated clinical diagnoses of LPR (n = 105) or GERD (n = 82). Conventional impedance-pH measures and MNBI were analysed for the two groups. Results MNBI was significantly lower in the distal esophagus in GERD patients compared with LPR (1679 ± 914 vs. 2109 ± 863; p = 0.001). Similarly, in the proximal esophagus, MNBI was lower in GERD than LPR (2289 ± 579 vs. 2541 ± 471; p = 0.001). In the pharynx, MNBI was similar between the two groups (2116 ± 699 vs. 2133 ± 770; p = 0.878). Distal acid exposure time (AET) and the number of distal acid reflux episodes negatively correlated with distal esophageal MNBI (r = −0.195; p = 0.007) and (r = −0.330; p < 0.001) respectively. Conclusion Baseline impedance was reduced in both LPR and GERD at both distal and proximal esophageal measurements, and more severely reduced in GERD. Baseline impedance is strongly and inversely related to acid exposure in the esophagus. Pharyngeal MNBI was not reduced or different between groups. Distal and proximal esophageal MNBI may be useful in diagnosis of LPR as well as GERD.

Sex-Based Differences in pH Parameters and Esophageal Impedance of Patients With Gastroesophageal Reflux Disease

Background/Aims: The incidence of reflux esophagitis (RE) has a striking predominance in males. Conversely, non-erosive reflux disease (NERD) is more common in females. This imbalance of gastroesophageal reflux disease (GERD) implies sex-related differences in its pathogenesis. However, limited studies have analyzed the sex-based differences in pH parameters and esophageal impedance of GERD patients.Methods: This study evaluated sex-based pathogenesis differences by comparing reflux episodes, mean nocturnal baseline impedance (MNBI) values, and post-reflux swallow-induced peristaltic wave (PSPW) index values of males with GERD and females with GERD using 24-h multichannel intraluminal impedance and pH monitoring.Results: We analyzed 181 patients (102 males and 79 females) with GERD. Reflux symptom index (RSI) scores were higher in females than that in males (P < 0.05). Males had significantly longer acid exposure times, higher DeMeester scores, and more acid reflux episodes than females (P < 0.05). Females had more instances of weakly acidic reflux than males (P < 0.01). The PSPW index values of males and females were similar (P > 0.05). Compared with females, males had lower MNBI values for the mid and distal esophagus (P < 0.05). However, with increasing age, the MNBI values of females decreased more rapidly than those of males. MNBI values of elderly patients of both sexes older than 60 years were similar.Conclusions: Acid reflux is more likely to occur in males; however, females tend to have more instances of weakly acid reflux. The integrity of the esophageal mucosa is more fragile in males than in females; however, the esophageal mucosal barrier attenuates more rapidly with increasing age in females than in males.

Relationship between distension-contraction waveforms during esophageal peristalsis: effect of bolus volume, viscosity, and posture

We studied esophageal distension (surrogate of inhibition) ahead of contraction during peristalsis from intraluminal esophageal impedance measurements. Esophageal distension, similarly to contraction, travels the esophagus in a sequential manner, and the amplitude of esophageal distension increases from proximal to distal direction in the esophagus. Bolus volume, viscosity, and posture have significant effects on the amplitude of distension and its temporal relationship with contraction.