CO2 wedged hepatic venography in the evaluation of portal hypertension

Background/aims/methods-During hepatic vein catheterisation, in addition to measurement of hepatic venous pressure gradient (HVPG), iodine wedged retr ograde portography can be easily obtained. However, it rarely allows correc t visualisation of the portal vein. Recently, CO2 has been suggested to all ow better angiographic demonstration of the portal vein than iodine. In thi s study we investigated the efficacy of CO2 compared with iodinated contras t medium for portal vein imaging and its role in the evaluation of portal h ypertension in a series of 100 patients undergoing hepatic vein catheterisa tion, 71 of whom had liver cirrhosis. Results-In the overall series, CO2 venography was markedly superior to iodi ne, allowing correct visualisation of the different segments of the portal venous system. In addition, CO2, but not iodine, visualised portal-systemic collaterals in 34 patients. In cirrhosis, non-visualisation of the portal vein on CO2 venography occurred in II cases; four had portal vein thrombosi s and five had communications between different hepatic veins. Among non-ci rrhotics, lack of portal vein visualisation had a 90% sensitivity, 88% spec ificity, 94% negative predictive value, and 83% positive predictive value i n the diagnosis of pre-sinusoidal portal hypertension. Conclusions-Visualisation of the venous portal system by CO2 venography is markedly superior to iodine. The use of CO2 wedged portography is a useful and safe complementary procedure during hepatic vein catheterisation which may help to detect portal thrombosis. Also, lack of demonstration of the po rtal vein in non-cirrhotic patients strongly suggests the presence of pre-s inusoidal portal hypertension.