COMPOSITION AND CONCENTRATION OF BILE-ACID REFLUX INTO THE ESOPHAGUS OF PATIENTS WITH GASTROESOPHAGEAL REFLUX DISEASE

Background. Reflux of duodenal contents into the esophagus of patients with gastroesophageal reflux disease has been suggested by pH and bil irubin monitoring but is rarely directly measured. A portable device h as been developed and was used to collect and quantitate material refl uxed into the esophagus under ambulatory conditions during a prolonged time period. The objective of this study was to use this device to qu antitate the composition and concentration of bile acids refluxed into the esophagus of patients with gastroesophageal reflux disease. Metho ds. Esophageal aspiration was performed on 43 normal subjects and 37 p atients with reflux disease during a 17-hour period. Aspiration was pe rformed through a modified 16F Salem sump tube, positioned 5 cm above the lower esophageal sphincter and connected to a portable, battery po wered pump that aspirated continuously at 100 mm Hg pressure. Validati on studies showed that minimal amounts of saliva and swallowed liquids were aspirated and that gastric pressure was not altered. Postprandia l, upright, and supine collections were performed. Total bile acids we re assayed by a standard enzymatic assay; specific conjugated bile aci ds were analyzed by high-performance liquid chromatography. Results. T here was no difference in the total aspiration volume between normal v olunteers and patients with gastroesophageal reflux disease, although patients tended to have a higher volume in the supine and postprandial periods. Bile acids could be detected in 58% of normal subjects and 8 6% of patients (p<0.003). The mean concentration of bile salt exposure (micromole per liter) was higher in patients during the postprandial and supine periods. The mean bile acid reflux rate (micromole per hour ) during all three aspiration periods was significantly higher in pati ents. On a molar basis the composition of the bile acids was 60% glyco cholic acid, 16% glycodeoxycholic acid, and 15% glycochenodeoxycholic acid. Taurocholic, taurodeoxycholic, taurochenodeoxycholic, and glycol ithocholic acid constituted the remaining 10%. Conclusions. Patients w ith reflux disease have an increased concentration of bile acids in th eir esophageal aspirates. Most of the exposure occurs during the postp randial and supine periods. A variety of bile acids were detected, mos t of which were in their glycine conjugated form.