Endoscopic ultrasound duplex scanning for measurement of portal venous flow - Validation against transit time ultrasound flowmetry in pigs

Background: Endoscopic ultrasound (EUS) is a new technique that makes it po ssible to measure portal venous flow when transabdominal ultrasound fails. As the technique has not been evaluated previously, we compared simultaneou s measurements of portal venous flow using EUS Doppler with that of transit time ultrasound (TTU) in healthy pigs. The ability of EUS to detect change s in the portal venous flow after pharmacologic intervention was also inves tigated. Methods: Six anaesthetized pigs were studied. Portal venous flow w as measured simultaneously by EUS duplex scanning, using a Pentax FG-32UA e choendoscope connected to a Hitachi EUB 515-A ultrasound scanner, and by TT U with a Cardiomed CM 4000 flowmeter probe placed on the portal vein. Terli pressin, 1 mg, and placebo were administered in a blind, randomized, crosso ver design. Measurements were taken at base line and 30 min after each drug administration. Results: Portal venous flow measured by EUS flowmetry and TTU flowmetry correlated significantly (R = 0.92, P < 0.001, n = 18). The L imits of agreement in a Bland-Altman plot were from -0.262 l/min to +0.164 l/min. The change in portal venous flow after terlipressin measured by EUS and TTU correlated significantly (R = 0.88, P < 0.05, n = 6). All values us ed for analyses were the means of five repeated measurements. Conclusions: EUS measures portal venous flow with an acceptable correlation and agreemen t with TTU in anaesthetized pigs. The method is capable of monitoring the e ffects of pharmacologic intervention on the portal system.