Manometric artefacts suggesting compression of the duodenum by the superior mesenteric artery in healthy humans

Multi-channel manometry offers the opportunity to study intestinal motor ac tivity with high spatiotemporal resolution. We report tonic and phasic intr aluminal pressure changes in the midportion of the horizontal part of the d uodenum. In 10 healthy volunteers, we recorded 2 h of interdigestive duoden al motility using a water-perfused catheter. The assembly incorporated 12 d uodenal sideholes at 1.5-cm intervals (D1-D12). Measurement of the antral a nd duodenal transmucosal potential difference (TMPD) was used to maintain a correct position of the catheter. The incidence of pressure waves (PWs inc reased gradually from proximal (D1) to distal (D12) (P < 0.0001), while the mean amplitude of PWs decreased (P < 0.0001). In eight of 10 subjects, the signals recorded from D9 showed tonic pressure elevations with superimpose d phasic pressure changes at heart-rate frequency comprising 13.8% of total recording time. In the other two subjects, this phenomenon occurred in D8 (9.9% of time). D10 showed a lower incidence of PWs compared with neighbour ing sideholes (D6-D9/D11-D12) (P < 0.035), with normal amplitudes. Fluorosc opy was performed in three subjects and showed that D9 was located at the m idline. In healthy subjects manometric signals recorded from the horizontal part of the duodenum showed localized artefacts, presumably caused by comp ression by the superior mesenteric artery. In addition, a 'silent' region w as present lust distal to this site, the origin of which is uncertain.