Abstracts
1999 Digestive Disease Week

# 2100 A MANOMETRIC INDICATOR OF ESOPHAGEAL OUTFLOW RESITANCE: RAMP INTRABOLUS PRESSURE
A A Nisim, O L Gastal, Univ of Southern CA, Los Angeles, CA; J Johansson, G.M. R Campos, M Hashemi, Univ of Southern CA Dept of Surg, Los Angeles, CA; R N. Lord, J Theisen, P F Crookes, T R DeMeester, C G Bremner, Univ of Southern CA, Los Angeles, CA

Background: Ramp intrabolus pressure (rBP) is a waveform on esophageal manometry which precedes the peristaltic upstroke resulting from a single swallow and may be an indicator of outflow resistance. The aims of this study were to define normal criteria for rBP and to compare normal values with those in patients with hypertensive lower esophageal sphincter and in patients with GERD who underwent Nissen fundoplication.
Methods: Intrabolus pressure was measured as the mean point above baseline after a 5 ml swallow of water between onset and termination of rBP. 158 esophageal manometry tracings were analyzed for the following groups: 53 asymptomatic volunteers (AV), 31 patients with a diagnosis of a hypertensive lower esophageal sphincter (H-LES) and 37 GERD patients with pre and post operative studies who had a good or excellent outcome after Nissen fundoplication (NF).
Results: The median amplitude and duration of rBP during 5 ml swallows of water were measured at 4 different levels within the esophagus. In AV, rBP was a frequent finding (96%). The 95th percentile of the rBP amplitude was 11 mmHg and of the rBP duration was 14.2 seconds. There was no difference in amplitude or duration between the different levels. H-LES patients displayed higher amplitudes and durations of rBP at 3 of the 4 levels within the esophagus compared with AV (p<0.05). The NF post operative rBP amplitude was higher than both the pre-operative NF and the AV values at a single level of 5 cm above the LES (p<0.001).
Conclusion: rBP was a frequent manometric finding and normal limits were defined. In patients with H-LES both amplitude and duration of rBP are significantly higher than those of AV. There is an increase in amplitude and duration of rBP in the distal esophagus after Nissen fundoplication. These findings may support the clinical application of rBP as a tool in the assessment of esophageal outflow resistance in disease and in the post operative state.

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