Reflux episodes and esophageal impedance levels in patients with typical and atypical symptoms of gastroesophageal reflux disease

Abstract

To determine the relationship between baseline impedance levels and gastroesophageal reflux, we retrospectively enrolled 110 patients (54 men and 56 female; mean age, 51 ± 14 years) with suspected gastroesophageal reflux disease (GERD) who underwent 24-h multichannel intraluminal impedance and pH monitoring. Patients were stratified according to symptom (typical or atypical) and reflux types (acid reflux, nonacid reflux [NAR], or no abnormal reflux). Mean nocturnal baseline impedance (MNBI) were measured 3 cm (distal esophagus) and 17 cm (proximal esophagus) above the lower esophageal sphincter. Median distal esophageal MNBI was lower in the acid reflux group (1244 Ω; 647-1969 Ω) than in the NAR (2586 Ω; 1368-3666 Ω) or no abnormal reflux groups (3082 Ω; 2495-4472 Ω; all P < .05). Distal MNBI were negatively correlated with DeMeester score and acid exposure time. Atypical symptoms were more frequently associated with NAR than typical symptoms (P < .01). Among patients with positive symptom-association probability (SAP) for NAR, median proximal MNBI tended to be lower in patients with typical symptoms (median, 3013 Ω; IQR, 2535-3410 Ω) than in those with atypical symptoms (median, 3386 Ω; IQR, 3044-3730 Ω, P = .05). Thus, atypical GERD symptoms were more likely to be associated with NAR. The mucosal integrity of the proximal esophagus might be relatively impaired in GERD patients with typical symptoms for NAR.

Figure 1

MNBI at the distal and proximal esophagus among different reflux groups. (A) Proximal esophageal MNBI do not differ among the study groups (P > .05). (B) Distal MNBI are lower in patients with acid reflux than in patients with NAR and nonreflux subjects (all P < .05). No difference in MNBI is present between patients with NAR and nonreflux subjects (P > .05). MNBI = mean nocturnal baseline impedance, NAR = nonacid reflux.

Figure 2

Distal MNBI are negatively correlated with (A) AET (r = −0.48, P < .01) and (B) DeMeester score (r = −0.37, P < .01). AET = acid exposure time, MNBI = mean nocturnal baseline impedance.

Figure 3

Relationship among typical and atypical symptoms of GERD, and reflux types. GERD = gastroesophageal reflux disease, NAR = nonacid reflux, SAP = symptom-association probability.

Figure 4

Correlation between symptom-reflux association and MNBI. (A) A trend of lower proximal MNBI is seen in patients with typical symptoms and positive SAP for NAR compared with patients with atypical symptoms and positive SAP for NAR (P = .05). (B) No differences in distal MNBI are seen between patients with typical and atypical symptoms with positive SAPs for acid reflux, and between patients with typical and atypical symptoms with positive SAPs for NAR (P > .05). MNBI = mean nocturnal baseline impedance, NAR = nonacid reflux, SAP = symptom-association probability.