6993 Biliary intraductal pressure measurement has low sensitivity for diagnosis sphincter of oddi dysfunction (sod).

Abstract

BACKGROUND: Intraductal biliary pressure measurement has been proposed as the substitute for basal sphincter pressure for diagnosis of SOD. Intraductal pressure measurement is technically easier to perform than station pull-through sphincter of Oddi (SO) manometry and may be appropriate since one mechanism of pain in patients with SOD is attributable to elevated intraductal pressure. This study evaluated the correlation of biliary basal sphincter pressure and intraductal biliary pressures. METHODS: 59 patients with suspected SOD were prospectively studied. Intraductal biliary pressure was measured in calmly sedated patients with the standard 5 Fr triple lumen SOM catheter passed 2-4 cm above the sphincter as confirmed on fluoroscopy. Thereafter the conventional pullthrough SOM was performed. Conscious sedation was achieved with combination diazepam and droperidol, (and meperidine, if needed). A subgroup of 20 patients with prior biliary sphincterotomy had separate analysis. RESULTS: Elevated SO basal pressure >40 mmHg was seen in 28 of 39 patients. In 9 of these 28 patients (32 %) intraductal pressure at greater than 12 mmHg. One of 11 patients with normal SO basal pressure had elevated intraductal pressure. Mean intrabiliary pressure was 9.7 ± 5.3 mmHg in patients with SOD and 8.8 ± 5.4 mmHg in patients with normal SO basal pressure (p=0.63). Stratification of patients according to presence or absence of intact gallbladder did not improve sensitivity. Patients with gallbladder intact (n=8) tended to have lower intraductal pressure than patients with gallbladder removed (6.5 ± 3.0 mmHg vs. 10.2 ± 5.5 mmHg; p=0.07). This phenomenon was independent of SOD diagnosis. Moreover intraductal pressure was strongly influenced by meperidine administration (n=21; 11.4 ± 5.0 mmHg vs. 7.0 + 4.6 mmHg: p<0.01) and the use of guide-wire (n=8; 12.9 ± 4.2 mmHg vs. 8.5 ± 5.2 mmHg; p=0.03), while SO basal pressure was not affected. All 20 patients with prior biliary sphincterotomy had SO basal pressure within normal range, whereas 1 patient had elevated intraductal pressure >12 mmHg (presumed false positive). SUMMARY: Using >12 mmHg as a cut off, intraductal biliary pressure has low sensitivity for detection of SOD defined as basal biliary sphincter pressure of >40 mmHg. CONCLUSION: Intraductal biliary basal pressure is a poor substitute for the established standard of >40 mmHg basal sphincter pressure for diagnosis of SOD.