An improved pressure-sensitive capsule for endoscopic measurement of esophageal variceal pressure.

A new small noninvasive pressure-sensitive capsule for the endoscopic measurement of esophageal varix pressure was evaluated and compared to an initial Yale-designed capsule to test the hypothesis that the diameter of the capsule measuring surface is a limiting factor for the accuracy and variability of capsule pressure measurements. Capsule pressures obtained with each capsule, using rabbit mesenteric vessels comparable in size to human esophageal varices, were correlated with direct intraluminal pressure measurements. There was an excellent correlation between capsule pressure measurements obtained with the small capsule and intraluminal pressure (r2 = 0.97) which was significantly greater than the correlation obtained when the initial capsule was studied (r2 = 0.89, P less than 0.01). The variability of capsule pressure measurements obtained with the small capsule was less than that observed when measurements were obtained with the initial capsule (P less than 0.01). Therefore, this new small capsule should provide the most accurate and reproducible noninvasive measurements of variceal pressure.