Muscle shortening along the normal esophagus during swallowing.

Longitudinal shortening of the esophagus during peristaltic contraction has been previously analyzed globally using spaced mucosal clips. This method gives a relatively crude measurement. In this study, local longitudinal shortening (LLS) was evaluated using simultaneous high-resolution endoluminal ultrasound (HREUS) and manometry based on basic principles of muscle mechanics. We sought to determine if there are regional differences in LLS of the esophageal muscle during swallow-induced peristaltic contraction and evaluate shortening of the circular smooth muscle (CSM) and longitudinal smooth muscle (LSM) of the esophagus. Twenty normal subjects underwent simultaneous HREUS/manometry at 4 levels (5, 10, 15, and 20 cm above the upper border of the lower esophageal sphincter [LES] high-pressure zone) in the esophagus with 5-mL swallows of water. Ultrasound images were recorded with synchronized manometric pressure data. The images were digitized and the cross-sectional surface area (CSA) of the LSM, CSM, and total muscle (TM) were measured at baseline (at rest) and at peak intraluminal pressure (implying peak CSM contraction) during swallowing. LLS was calculated for the CSM and LSM using the principle of mass conservation, whereby the change in CSA relative to the resting CSA is quantitatively equal to the relative change in length of a local longitudinal muscle segment.CSM, LSM, and TM all shortened longitudinally, with the circular muscle shortening more than the longitudinal muscle, LLS of the CSM and TM layers at 5 cm above the LES was significantly greater than at 20 cm (CSM: 30% difference, P < .001; TM: 18% difference, P < .05). The greater shortening of LSM at 5 versus 20 cm was found not to be statistically significant (11% difference, P > .05). Peak intraluminal pressure strongly correlated with peak muscle thickness of all layers at all levels (r = 0.96-0.98).LLS increases from the proximal to the distal esophagus during bolus transport. CSM and LSM both shorten longitudinally, with CSM shortening more than LSM. The increase in LLS increases the efficiency of peristaltic contraction and likely contributes to the axial displacement of the LES preceding hiatal opening and esophageal emptying.

Volume (3-dimensional) space-time reconstruction of esophageal peristaltic contraction by using simultaneous US and manometry.

BACKGROUND: Conventional 3-dimensional endoluminal US was modified to evaluate peristaltic contractions in the esophagus. METHODS: Two-dimensional US images and simultaneous intraluminal pressures were acquired during peristaltic contractions by locating the transducer at fixed positions in the esophagus in 6 normal volunteers during swallowing. Three-dimensional images were reconstructed by using a computer-based 3-dimensional algorithm with time as the x axis. RESULTS: The peristaltic contraction sequence was viewed as a 3-dimensional US image. The geometric configuration of the esophagus, the muscle thickness, and corresponding pressures were evaluated. The 3-dimensional images demonstrate 4 phases of the peristaltic contraction sequence. CONCLUSIONS: Three-dimensional time-resolved reconstruction of endoluminal US images of the esophagus and simultaneous recording of manometric data allow visualization of geometric changes and correlation with pressure changes during peristaltic contraction. Four phases of the peristaltic contraction sequence are demonstrated clearly on the 3-dimensional space-time images.

Comparison of a salivary/sputum pepsin assay with 24-hour esophageal pH monitoring for detection of gastric reflux into the proximal esophagus, oropharynx, and lung.

The purpose of this study was to determine whether measurement of salivary/sputum pepsin could be used as a surrogate marker for detecting gastroesophageal reflux using 24-hr esophageal pH monitoring as the gold standard. Patients with gastroesophageal reflux symptoms underwent simultaneous 24-hr esophageal pH monitoring and collection of saliva and sputum samples for pepsin measurement using a recently developed assay. In all, 16 patients provided 19 positive (10.6%) and 161 negative pepsin assays. The mean pH values for the positive pepsin samples were lower then the negative samples at both the proximal [5.34 (95% CI, 4.94-5.75) vs 6.12 (95% CI, 6.03-6.20; P < 0.01)] and distal [4.97 (95% CI, 4.61-5.33) vs 6.03 (95% CI, 5.92-6.15; P < 0.01)] pH probes. Proximal esophageal reflux was not detected in patients who had a negative pepsin assay (N = 12); in contrast, proximal esophageal reflux was documented in three of four patients with a positive assay. In conclusion, detection of pepsin in the saliva and/or sputum may provide a noninvasive method to test for the proximal reflux of gastric contents.