Use of simultaneous high-resolution endoluminal sonography (HRES) and manometry to characterize high pressure zone of distal esophagus.

The purpose of this investigation was to separate the high pressure zone (HPZ) of the distal esophagus into its two components, the intrinsic lower esophageal sphincter (LES) and the extrinsic crural diaphragm (CD), using simultaneous esophageal manometry and high-resolution endoluminal sonography. Five normal subjects were studied during end inspiration using a dual manometry/ultrasound catheter. The HPZ in the distal esophagus was characterized ultrasonographically as the CD distally and as an overlap of CD and LES proximally. In four of five volunteers, the initial distal rise in pressure at the HPZ corresponded to imaging of CD rather than imaging of the LES. In all subjects, peak pressure corresponded to an overlap of CD and LES. In conclusion, it is possible to divide the HPZ into its two components, the LES and CD using simultaneous high-resolution endoluminal sonography and esophageal manometry. During end inspiration, the CD contributes to the initial distal rise in pressure at the HPZ. Peak pressure of the HPZ corresponds to an overlap of the LES with the CD.