Correlation between esophageal contraction amplitude and lower esophageal sphincter pressure in patients with nutcracker esophagus

Nutcracker esophagus (NE) is a primary esophageal motility disorder characterized by high-wave amplitude at the distal esophagus. The aim of this study was to analyze patients with NE and determine the relationship between distal esophageal contraction amplitude and lower esophageal sphincter (LES) pressure. Esophageal manometry tracings of patients with NE, defined as the presence of distal contraction amplitude of more than 182 mmHg after wet swallow, were analyzed. LES pressure was measured as the mean end-expiratory value. Spearman's correlation coefficient analysis was used to compare esophageal contraction amplitude with LES pressure. This comparison was also performed in patients with isolated hypertensive LES (HLES) and in subjects with normal manometry. Forty patients (25 female, 15 male; mean age 54 years) with NE were included in the study. Mean (SD) distal esophageal contraction amplitude was 230 (35.7) mmHg and mean LES pressure was 27.3 (5.7) mmHg. Esophageal contraction amplitude showed a positive correlation with LES pressure (r = 0.49, P < 0.01). In contrast, no correlation was found in patients with HLES (r = 0.21, P > 0.05) and in those with a normal manometric study (r = 0.18, P > 0.05). It is concluded that in patients with nutcracker esophagus a positive correlation exists between distal esophageal contraction amplitude and LES pressure, suggesting a diffuse hypertensive pattern involving smooth muscle at the distal esophagus and adjacent LES.