The influence of variable-stiffness guide wires on basal biliary sphincter of Oddi pressure measured at endoscopic retrograde cholangiopancreatography

Background: Guide wires are commonly utilized to facilitate endoscopic procedures. However, their use may adversely influence the results of sphincter of Oddi manometry, thereby leading to erroneous diagnosis and therapy. The aim of this study was to evaluate the effect of guide wires on the basal pressure of the biliary sphincter of Oddi. Methods: Forty-five consecutive patients with suspected sphincter of Oddi dysfunction were enrolled. Biliary sphincter of Oddi manometry was performed with and without a guide wire in the conventional retrograde fashion with a low-compliance infusion pump system, an aspirating catheter, and slow station pull-throughs. Three types of guide wires were studied: the Roadrunner (18 patients), the Glidewire (17 patients), and the standard Teflon guide wire (10 patients). The stiffness of the guide wires was tested and reported in Taber Stiffness Units (TSU; higher values represent greater stiffness). Results: Biliary sphincter of Oddi manometry performed with a guide wire revealed higher basal pressure than the same measurement performed without a guide wire (52 +/- 33.4 mmHg vs. 34.4 +/- 20.5 mmHg; P = 0.001). Basal pressure changes induced by guide-wire use were highest in the Roadrunner group (32.9 +/- 33.9 mmHg), lowest in the standard Teflon group (11.6 +/- 8 mmHg; Roadrunner vs. standard Teflon: P = 0.02), and intermediate in the Glidewire group (17.1 +/- 22.1 mmHg). The use of a guide wire resulted in crossover from normal to abnormal basal pressure in 11 cases (Roadrunner, 7; Glidewire, 4) and from abnormal to normal in 2 (Roadrunner, 1; Glidewire, 1). Concordance between recordings obtained with and without guide wire was seen in 32 patients (71 %). Guide-wire stiffness was: Roadrunner: 0.74 TSU; Glidewire: 0.153 TSU; standard Teflon guide wire: 0.077 TSU. Conclusion: The use of guide wires frequently alters the basal biliary sphincter pressure, leading to incorrect diagnoses in approximately 40% of cases. The basal pressure alterations depend on the stiffness of the guide wire used. Hence, the use of guide wires during sphincter of Oddi manometry is strongly discouraged.