Pathophysiology of chest pain in patients with nutcracker esophagus.

Objectives: Nutcracker esophagus is a manometric pattern that is commonly seen in patients with functional (noncardiac) chest pain. However, this pattern is often unassociated with pain. Consequently, the pathophysiology of chest pain in these patients is unclear.
Methods: We prospectively examined the sensory perception and biomechanical properties of the esophagus in 10 patients with chest pain and a nutcracker esophagus, along with those properties in 12 healthy controls using impedance planimetry.
Results: Stepwise balloon distentions reproduced typical chest pain in 9/10 (90%) patients. The threshold for chest pain was lower (p < 0.05) in patients than in controls (mean +/- SD 43+/-5 vs 62+/-4 cm H2O) but only 2/12 controls experienced pain. The thresholds for first perception and moderate discomfort were also lower (18+/-8 vs 30+/-11 cm H2O, p < 0.01 and 28+/-9 vs 62+/-5 cm H2O, p < 0.001) in patients than in controls, but only 3/12 controls experienced moderate discomfort. The esophageal reactivity to balloon distention was higher in patients than in controls (p < 0.001). The tension-strain curve shifted to the left in the patient group when compared to that in the controls (p < 0.05).
Conclusions: Patients with a nutcracker esophagus demonstrate a hypersensitive and stiff esophagus. Because balloon distention reproduced their chest pain, visceral hyperalgesia of the esophagus may be relevant to the pathogenesis of their pain. Balloon distention test may be more useful in the evaluation of patients with functional chest pain and a nutcracker esophagus.