Asynchrony between the circular and the longitudinal muscle contraction in patients with nutcracker esophagus

Background & Aims: The increases in intraluminal pressure and muscle cross-sectional area (CSA) during esophageal contraction are markers of circular and longitudinal muscle contractions. The goal of our study was to determine temporal synchrony between circular and longitudinal muscle contraction in healthy subjects and patients with nutcracker esophagus. Methods: Pressure and high-frequency intraluminal ultrasound (HFIUS) images were recorded simultaneously in healthy subjects and patients with nutcracker esophagus at 2 and 10 cm above the lower esophageal sphincter during wet swallow. HFIUS images were digitized and analyzed for the muscle CSA. The time interval (delta-t) between the peak muscle CSA and the peak pressure was determined. Results: In healthy subjects, a close temporal correlation existed between the peak contraction pressure and the peak muscle CSA with a maximum delta-t of 0.5 seconds at the 2- and 10-cm levels (0-0.5 seconds). On the other hand, the patient group had a median delta-t of 1.25 seconds (0.75-3.5 seconds) at the 2-cm level and 0.75 seconds (0-2.0 seconds) at the 10-cm level. Ninety-eight of 103 contractions in patients showed a delta-t > 0.5 seconds. There was a significant correlation between delta-t and the amplitude of pressure wave, the duration of pressure wave, and the peak muscle CSA. The duration of pressure wave but not the duration of CSA wave was longer in patients with nutcracker esophagus as compared with healthy subjects. Conclusions: Patients with nutcracker esophagus show temporal asynchrony between the contractions of circular and longitudinal muscle layers.