Endoscopic Retrograde Cholangiopancreatography (ERCP), But Not EGD Or Colonoscopy, Significantly Increases Portal Venous Pressure: Direct Portal Pressure Measurements Through EUS-Guided Catheterization

Abstract

Background: Despite the long history of flexible endoscopy use in clinical practice, some of its physiological effects are not completely understood. Elevated intraluminal pressure due to air insufflation during endoscopy is thought to increase intra-abdominal pressure. Increased intra-abdominal pressure has been associated with multiple adverse physiological effects such as elevated systemic vascular resistance, elevated venous pressure, diminished visceral and renal perfusion, and even an elevation in intracranial pressure. However, changes in portal pressure during endoscopy have not been previously studied. We have recently developed endoscopic ultrasound (EUS)-guided catheterization technique which allows continuous direct measurements of portal vein (PV) pressure. Aim: To assess the effects of upper endoscopy (EGD), colonoscopy, and ERCP on PV, intra-abdominal and systemic pressures. Methods: Five acute experiments were performed on 50-kg pigs. EUS-guided catheterizations of the PV and the inferior vena cava (IVC) were performed. Systemic, intra-abdominal, IVC and PV pressures were continuously monitored during colonoscopy, EGD, and ERCP with endoscopic sphincterotomy. After endoscopy the animals were sacrificed for necropsy. Results: Successful catheterizations of the PV and IVC were achieved in all 5 pigs. There were no significant changes in PV, IVC and intra-abdominal pressures during EGD and colonoscopy. Mean PV pressure increased almost 3-fold after injection of a contrast into the common bile duct (35.2 ± 9.6 mm HG vs. 13.4 ± 3.6 mm HG at baseline, p = 0.01). PV pressures were the highest at the time of biliary sphincterotomy in all 5 pigs (39.0 ± 15.1 mm HG). Mean IVC pressure was also elevated during ERCP compared to baseline, but this change did not reach statistical significance (24.0 ± 10.7 mm HG vs. 12.6 ± 4.0 mm HG, p = 0.07). Intra-abdominal pressure was increased as well during ERCP, although the difference was not statistically significant (p = 0.053). There were no significant changes in systemic pressure and heart rates during all endoscopic procedures. Necropsy did not reveal any complications or damage due to endoscopy or PV and IVC catheterization. Conclusion: EGD and colonoscopy did not cause significant changes in systemic, IVC, PV or intra-abdominal pressures. ERCP with biliary sphincterotomy selectively increased portal pressure without any effect on intra-abdominal, IVC, and systemic pressures. These new data indicate an association between biliary ductal and portal venous pressure, and this may be clinically important for patients with portal hypertension undergoing ERCP.