Mechanisms of excessive esophageal acid exposure in patients with reflux esophagitis.

The pathophysiology of excessive esophageal acid exposure, including the way refluxed acid extends towards the proximal esophagus, in patients with reflux esophagitis (RE), is not yet clear. For 3 h after a meal, concurrent esophageal manometry and pH monitoring was carried out on 14 patients with severe RE, 15 patients with mild RE, and 15 healthy subjects. At 2 cm above the proximal margin of the lower esophageal sphincter (LES) there was no difference between the three groups in the total number of acid-reflux episodes, the rate of transient LES relaxations (TLESRs), or the rate of acid reflux during TLESRs. The rate of acid reflux at 7 cm above the proximal margin of the LES, during TLESRs, in patients with severe RE (50.9%, median) was, however, significantly higher than in patients with mild RE (35.7%) and healthy subjects (15.4%). In addition, the rate of acid reflux during TLESRs in patients with mild RE was significantly higher than in healthy subjects. Both the amplitude and the success rate of primary peristalsis in patients with severe RE were significantly lower than those of healthy subjects and patients with mild RE but there was no difference between healthy subjects and patients with mild RE. The cause of excessive acid exposure in patients with RE is the difference in the way refluxed acid extends towards the proximal esophagus and acid bolus clearance, not the number of acid-reflux episodes.