Postprandial gastric relaxation in achalasia

In achalasia the incidence of autonomic neuropathy is increased, indicating that achalasia is not a disease of the oesophagus only. Little information is available concerning the function of the stomach in achalasia. We compared the postprandial gastric fundus relaxation in patients with achalasia to that of healthy controls.

In six patients with achalasia and six healthy controls postprandial fundus relaxation after a liquid test meal (500 ml, 500 kcal) was studied using an intragastric bag connected to an electronic barostat. The postprandial gastric relaxation was measured as an increase of intragastric bag volume; bag pressure was set at a constant level of 1 mmHg above the intra-abdominal pressure. All data are given as means +/- SEM, and the Mann-Whitney test was used for statistical analysis.

The intragastric volume before ingestion of the test meal was not different between groups. The maximum relaxation in patients with achalasia was significantly lower than in controls (132+/-46 ml vs 238+/-70 ml, P< 0.02). Postprandial relaxation was diminished and shortened in patients with achalasia as compared with controls. Similarly, the area under the volume curve was significantly smaller in patients with achalasia than in controls (29.8+/-28.9 ml/h vs 102.9+/-58.4 ml/h, P< 0.03) consistent with a diminished postprandial relaxation.

Patients with achalasia show a decreased postprandial gastric relaxation compared with healthy controls. We hypothesize that the neural damage in achalasia is not restricted to the oesophagus, but also involves the proximal stomach.