Oesophageal tone in patients with achalasia

Abstract

Background-The diagnosis and classification of oesophageal motility disorders is currently based on assessment of the phasic contractile activity of the oesophagus. Tonic muscular contraction of the oesophageal body (oesophageal tone) has not been well characterised. Aim-To quantify oesophageal tonic activity in healthy subjects and in patients with achalasia. Patients-Oesophageal tone was measured in 14 patients with untreated achalasia and in 14 healthy subjects. In eight patients with achalasia, oesophageal tone was again measured one month after either endoscopic or surgical treatment. Methods-Tonic wall activity was quantified by means of a flaccid intraoesophageal bag, 5 cm long and of 120 ml maximal capacity, which was placed and maintained 5 cm above the lower oesophageal sphincter and connected to an external electronic barostat. The experimental design included measurement of oesophageal basal tone and compliance as well as the oesophageal tone response to a nitric oxide donor (0.5 ml amyl nitrite inhalation). Results-Oesophageal basal tone, expressed as the intrabag (intraoesophageal) volume at a minimal distending pressure (2 mm Hg), did not diVer significantly between patients with achalasia and healthy controls (6.6 (2.5) ml versus 4.1 (0.8) ml, respectively). Oesophageal compliance (volume/pressure relation during intraoesophageal distension) was significantly increased in achalasia (oesophageal extension ratio: 3.2 (0.4) ml/mm Hg versus 1.9 (0.2) ml/mm Hg; p< 0.01). Amyl nitrite inhalation induced oesophageal relaxation both in patients and in controls, but the magnitude of relaxation was greater in the latter (intrabag volume increase: 15.3 (2.4) ml versus 36.2 (7.1) ml; p<0.01). Conclusion-In patients with achalasia, oesophageal tonic activity, and not only phasic activity, is impaired. Although oesophageal compliance is increased, residual oesophageal tone is maintained so that a significant relaxant response may occur after pharmacological stimulation. (Gut 1997; 41: 291-296)

Diminished mechanosensitivity and chemosensitivity in patients with achalasia

“…This finding is similar to that reported in preoperative achalasia patients by Gonzalez et al (8). One lingering question in that study is whether the observed difference in compliance was the result of the pathophysiology of achalasia itself or if it was a byproduct of the esophageal dilatation in the study population.…”

“…The barostat has been effectively used to measure esophageal tone and compliance, as it allows definition of pressure and volume relationships (14). A previous study by Gonzalez et al (8,11) using a barostat apparatus demonstrated increased esophageal compliance in untreated achalasia patients.…”

Hipocontratilidade do esôfago em pacientes com doença de chagas e pacientes com acalásia idiopática

“…A manutenção desta inervação com prejuízo de inervação inibitória provocaria aumento da amplitude. Associada à hipocontratilidade, os pacientes com acalásia (13) e com doença de Chagas (8) têm complacência da musculatura do esôfago aumentada, o que significa menor aumento da tensão quando da distensão da parede do órgão.…”

Oesophagitis is common in patients with achalasia after pneumatic dilatation

“…3,18 Besides, many achalasia patients, especially those who are older have an altered vagal afferent response leading to a diminished perception of pain. 19,20 In order to detect inflammation, surveillance endoscopy with adequate biopsy sampling is necessary. The interval between the surveillance endoscopies needs further investigation and this may be dependent on the level of inflammation.…”