529 Esophageal Contraction Wave Abnormalities on High Resolution Manometry (HRM) Not Meeting Chicago Classification Criteria: Are They Clinically Relevant?

Abstract

Introduction: The subjective perception of solid bolus hold up during swallowing is a common reason for referral for manometric investigation, yet standardmeasures of esophageal function relate poorly to patient perception and a large proportion of patients with dysphagia demonstrate no apparent abnormality on routine diagnostic testing for esophageal dysfunction. The utility of combined esophageal pressure-impedance recording has been recently enhanced by automated impedance manometry pressure-flow analysis (AIM analysis) and newmetrics have been conceived that better describe the interactions between bolus transport and pressure generation. In this study we undertook to assess whether these new esophageal pressure-flow metrics were altered when subjects perceived solid bolus hold up. Methods: Esophageal high-resolution pressure-impedance recordings of 5ml/10ml liquid/viscous swallows and 2cm/4cm solid swallows from 20 control subjects (29-73 years) were analysed. Two solid state pressure(P)/impedance(Z) catheter configurations were used; 32 1cm P/16 2cm Z (Sandhill Scientific) and 36 1cm P/18 2cm Z (Given Imaging). Bolus flow resistance, the relationship between bolus compression and bolus flow timing, was assessed using the pressure flow index (PFI) (Myers et al Neurogastro. Mot. 2012; Nguyen et al Neurogastro. Mot. 2012). Heightened perception of bolus hold up was assessed on a swallow by swallow basis using a 6 point scale (1 = no perception, 2 = awareness of bolus transit, 3-6 = bolus hold up). Results: On a swallow by swallow analysis, heightened perception of solid boluses (swallows with scores 3+) was associated with a higher PFI (distal esophagus Odds Ratio for score 3+ 1.001 [1.000 1.002], p = 0.021). A significant correlation was observed between the maximum subject reported perception score and the average PFI for solids (distal esophagus Pearson's r = 0.690, p,0.001). Grouping of subjects in relation to bolus perception revealed that the PFI was elevated for solids and viscous boluses, but not liquids, in subjects reporting bolus hold up (Figure). Esophageal peak pressures and iso-contour defect size were not significantly related to bolus perception. Conclusion: We report novel findings in relation to mechanical factors during bolus transport that may enhance bolus perception. This study shows that heightened perception of a swallowed bolus relates to subtle differences in flow resistance, which suggests higher levels of muscle tension during the transition phase from a bolus-containing to a lumen-occluded esophageal segment.