Clinical diagnostic value of mean nocturnal baseline impedance and post-reflux swallow-induced peristaltic wave index for distinguishing functional heartburn from non-erosive reflux disease

Introduction:
Functional heartburn (FH) and non-erosive reflux disease (NERD) are two prevalent diseases, with mean nocturnal baseline impedance (MNBI) and the post-reflux swallow-induced peristaltic wave (PSPW) index being used in their differentiation.

Aim:
We explored the clinical diagnostic value of MNBI and PSPW index on identifying FH and NERD.

Material and methods:
In total, 106 NERD and 82 FH patients were selected, and clinical data were collected. The mean low esophageal sphincter (LES) tone, distal contractile integral (DCI), contractile front velocity (CFV), and integrated relaxation pressure (IRP) were acquired. Acid exposure time (AET), total monitoring time, baseline impedance level, number of swallow-induced peristaltic wave reflux episodes within 30 s, total number of reflux episodes, and number of acid reflux episodes of NERD and FH patients were monitored, with AET, MNBI and the PSPW index being calculated. Correlations between MNBI and the PSPW index and pathological indicators of subjects, and the influence and diagnostic value of MNBI and the PSPW index for NERD and FH identification were analyzed.

Results:
The two groups differed significantly in AET, LES tone, total reflux episodes, acid reflux episodes and episodes of non-acid reflux. The NERD group displayed reduced MNBI and PSPW index levels. MNBI and the PSPW index were negatively associated with subject pathological indicators. MNBI, PSPW, LES tone, total reflux episodes and acid reflux episodes contributed to distinguishing NERD from FH. MNBI > 1975 and PSPW > 47.12 had high clinical application value for identifying NERD and FH.

Conclusions:
MNBI and PSPW, LES tone, total reflux episodes and acid reflux episodes aided in distinguishing NERD and FH. MNBI and PSPW combinative detection had high clinical application value for distinguishing NERD from FH.