Minimally invasive measurement of esophageal variceal pressure and wall tension

Background: There is no simple method to measure intravariceal pressure in patients with esophageal varices. Objective: Our purpose was to develop a new noninvasive technique to measure resting intravariceal pressure and wall tension. Design: A model was developed. A long balloon (varix) was fitted inside an airtight cylinder (esophagus). Fluid ran through the model varices to maintain 5 different constant pressures. Art endoscope was placed in the model esophagus, and pressure was increased by air insufflation. The endoscopy and pressure readings from the esophagus and varix were recorded continuously until variceal collapse. Setting: Patient studies were clone in an endoscopy suite with the patient under fentanyl and midazolam sedation. Patients: Esophageal pressure was measured during air insufflation in patients with varices until the varices collapsed. EUS was used to measure radius and wall thickness to calculate wall tension. Results: in the varix model, the mean (SD) intraluminal esophageal pressures at variceal flattening for the model varices at 5, 10, 15, 20, and 25 mm Hg were 5.69 (0.34), 11 (0.32), 15.72 (0.51), 21.55 (0.63), and 25.8 (0.14) mm Hg. The correlation between actual and measured variceal pressure in the model at variceal flattening was r = 0.98. In the patients, a total of 10 varices in 3 patients were evaluated. The mean (SD) for the varices in each Subject was 12.16 (2.4), 23.2 (1.3), and 6.5 (2.2) mm Hg for Subjects 1, 2, and 3, respectively Conclusion: Standard endoscopy with air insufflation and manometry can be used as an accurate, simple, and reproducible method to measure intravariceal pressure. (Gastrointest Endosc 2009;70:407-13.)