Loss of Alkalization in Proximal Esophagus: a New Diagnostic Paradigm for Patients with Laryngopharyngeal Reflux
Shahin Ayazi*, Jeffrey a. Hagen, Joerg Zehetner, Matthew Lilley, Priyanka Wali, Florian Augustin, John C. Lipham, Steven R. Demeester, Tom R. Demeester
Surgery, University of Southern California, Los Angeles, CA
Introduction: The use of proximal esophageal pH monitoring to diagnose laryngopharyngeal reflux (LPR) is disappointing. We hypothesized that failure to maintain adequate alkalization instead of acidification of the cervical esophagus may be a better indicator of proximal esophageal exposure to gastric juice. As currently performed, acidification of the proximal esophagus is defined by exposure to a pH<4. The normal pH in the cervical esophagus should be similar to the average pH of saliva (pH=7) and failure to maintain that pH may be a better indicator of acidification than a drop to pH<4. The aim of this study was to define normal value for the percent time the cervical esophagus is exposed to a pH>7 and to use the inability to maintain this as an indication of LPR.Material and methods: The normal subject group consisted of 59 asymptomatic volunteers who had a complete foregut evaluation including pH monitoring of the proximal esophagus. After analysis of proximal esophageal exposure to a pH<4 the records were reanalyzed to determine how effectively the cervical esophageal pH was maintained at a minimum pH of 7. The positive control group consisted of 51 patients who had complete relief of their LPR symptoms after an antireflux surgery and whose fundoplication was intact on videoesophagram. The preoperative proximal esophageal pH records of these patients were analyzed similar to the normal subjects for exposure to pH<4 and >7.Results: The median percent time the pH was >7 was significantly less in LPR patients prior to surgery compared to normal subjects [10.4 (2.8-21.9) vs. 38.2(27-56), p<0.0001]. This was also true for the time spent in the supine, upright and postprandial periods (p=0.0005). The 5th percentile value for the percent time that the cervical esophagus was exposed to a pH>7 in normal subjects was 19.6%. In 84% of the LPR patients (43/51) the percent time pH was >7 was less than 19.6, indicating they were unable to maintain a pH>7. In contrast, 69% of the patients (35/51) had an abnormal test when the pH records from proximal esophagus were analyzed using the % time pH<4. Of the 16 patients with a false negative test using pH<4, eleven (69%) were identified as having an abnormal study using the threshold of pH>7. Conclusion: Normal subjects are expected to have a pH>7 in cervical esophagus for at least 19.6% of the monitored period. Using the threshold value for pH>7 rather than <4 increases the sensitivity for diagnosis of the LPR by 15%. We propose using pH>7 as the threshold to identify reflux as the cause of LPR symptoms. It identifies two third of the patients whose analysis of their pH records using pH<4 is falsely normal.
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