N. Pallotta

Antro-pyloric contractile patterns and transpyloric flow after meal ingestion in humans

Objective:The present study aimed to evaluate the patterns of antral contractility and pylorus opening and closure in relation to transpyloric flow of a nutrient liquid meal.Methods:Ultrasound images of the antro-pyloro-duodenal tract were continuously tape-recorded in healthy volunteers for 1 h postprandially and were reviewed twice later by independent observers. Episodes and patterns of pylorus opening and closure, antral-wall contractions, and transpyloric flow were assessed separately and their time relations were identified.Results:Transpyloric flow (forward, 56%± 13%; retrograde, 19%± 11%; and to and fro, 25%± 14%) occurred essentially during episodes of prolonged pylorus opening not associated with occlusive antral or duodenal proximal contraction, which represented the antro-pyloro-duodenal common chamber. The antro-pyloro-duodenal common chamber lasted on average 36 ± 12 s and represented 41%± 12% of the total observation period. Different patterns of antral contractions were identified according to whether they reached or occluded the terminal antrum and pylorus. Preterminal antral contractions (46%± 12%) did not propagate beyond the proximal two thirds of the antrum. Terminal antral contractions (54%± 12%) propagated along the entire antrum and could either occlude (20%± 9%) or not occlude (42%± 17%) the lumen. Pyloric opening independent of antral contractions and related to nonocclusive antral contractions could occur equally at the onset of the antro-pyloro-duodenal common chamber. Pyloric closure independent of antral contractions put an end to transpyloric flow in 73%± 6% of the antro-pyloro-duodenal common chamber.Conclusion:The final passage of contents from the stomach to the duodenum after the ingestion of a caloric liquid meal is the result of one or more episodes of uni- or bi-directional transpyloric flow, which are regulated by several motor events. The contractile states of the antrum and pylorus show specific features that variably interrelate to provide mixing and to regulate the transpyloric flow of ingesta. A crucial regulator of transpyloric flow appears to be the spatiotemporal relation between antral contractions and pyloric closure rather than the contractile events per se. An equal number of pyloric openings related, and unrelated, to antral contractions appears to determine the onset of the antro-pyloro-duodenal common chamber and, thus, of transpyloric flow. Pyloric closure unrelated to antral contractions appears to be the main mechanism that interrupts transpyloric flow. In conclusion, it appears that the antro-pyloro-duodenal tract acts as a functional unit in the digestion of a liquid caloric meal.

Ultrasonographic detection and assessment of the severity of Crohn's disease recurrence after ileal resection

BackgroundRecurrence and severity of Crohns disease mucosal lesions after curative ileal resection is assessed at endoscopy. Intramural lesions can be detected as increased wall thickness at Small Intestine Contrast Ultrasonography (SICUS).Aims. To assess after ileal resection whether: 1) SICUS detects recurrence of Crohns disease lesions, 2) the intestinal wall thickness measured at the level of ileo-colonic anastomosis predicts the severity of endoscopic lesions, 3) the extension of intramural lesions of the neo-terminal ileum is useful for grading severity of the recurrence, 4) the combined measures of wall thickness of the ileo-colonic anastomosis and of the extension of intramural lesions at level of the neo-terminal ileum may predict the endoscopic Rutgeerts scoreMethodsFifty eight Crohns disease patients (M 37, age range 19-75 yrs) were prospectively submitted at 6-12 months intervals after surgery to endoscopy and SICUS for a total of 111 observations.ResultsSix months or more after surgery wall thickness of ileo-colonic anastomosis > 3.5 mm identified 100% of patients with endoscopic lesions (p < 0.0001). ROC curve analysis, combining wall thickness of ileo-colonic anastomosis and the extension of intramural lesions of neo-terminal ileum, discriminated (0.95) patients with, from those without, endoscopic lesions. Performing two multiple logistic regression analyses only wall thickness of ileo-colonic anastomosis and extension of neo-terminal ileum intramural lesions were significantly associated with absence or presence of endoscopic lesions. An ordinal polychotomus logistic model, considering all investigated variables, confirmed that only SICUS variables were associated with endoscopic grading of severity.ConclusionsIn patients submitted to ileal resection for Crohns disease non-invasive Small Intestine Contrast Ultrasonography 1) by assessing thickness of ileo-colonic anastomosis accurately detects initial, minimal Crohns disease recurrence, and 2) by assessing both thickness of ileo-colonic anastomosis and extension of intramural lesions of neo-terminal ileum grades the severity of the post-surgical recurrence.