Can multichannel intraluminal pH-impedance monitoring be limited to 3 hours? Comparison between ambulatory 24-hour and post-prandial 3-hour recording

Esophageal multichannel intraluminal pH-impedance recording (MII) is now a valid technique for determining the acidic, liquid, gas or mixed nature of gastroesophageal reflux episodes. However, some recordings may stop prematurely due to technical reasons or poor patient tolerance of the probe. Therefore, we questioned whether analysis of post-prandial 3-hour recording could predict the results obtained in ambulatory 24-hour recording. Fifty patients with symptoms of gastroesophageal reflux disease were investigated. For each patient, post-prandial 3-hour MII was recorded after a test meal, then followed by ambulatory 21-hour MII. Correlation between the total number of liquid reflux events in the 3-hour and 24-hour recordings was elevated (R = 0.71; P < 0.001), with better correlation for acid (R = 0.80; P < 0.001) and weak acid reflux (R = 0.56; P < 0.001) than non-acid reflux (R = 0.44;P < 0.01). Sensitivity and specificity of 3-hour recording in detecting elevated liquid reflux over 24 hours (id>75reflux/24h) were 49% and 100%, respectively, for 8 or less liquid/mixed reflux events per 3 hours, and 78% and 88%, respectively for 15 or more liquid/mixed reflux events per 3 hours. The sensitivity and specificity of symptom association probability (SAP) calculated over 3 hours were 56% and 91%, respectively. In conclusion, we identified relevant indicators on the 3-hour post-prandial recording likely to give accurate prediction of absence or presence of gastroesophageal reflux disease from 24-hour MII recording.