N-Butyl Cyanoacrylate Embolization with Blood Flow Control of an Arterioportal Shunt That Developed after Radiofrequency Ablation of Hepatocellular Carcinoma
A 70-year-old male with liver cirrhosis caused by hepatitis C virus was being followed up at our institution. As contrast-enhanced computed tomography (CE-CT) revealed three HCC lesions of < 15 mm in diameter in segments 1, 2, and 4; RFA of each lesion was performed. However, esophageal varices rapidly deteriorated at 3 months after RFA. Although endoscopic injection sclerotherapy was performed, the esophageal varices deteriorated further, and endoscopy showed greatly enlarged varices (F3) that were red in color (). According to Idezuki (), varices can be classified into three types based on their size: F1 varices are straight small caliber varices; F2 varices are larger with a bead-like appearance; and F3 varices are the largest, with a nodular or tumor-like shape. Red color signs indicate a high risk of bleeding from varices. Arterial phase CE-CT images revealed a marked arterioportal shunt in the left lateral segment of the liver () and portal thrombosis. Therefore, embolization of the arterioportal shunt was planned.\nAngiography of the common hepatic artery before embolization revealed a large arterioportal shunt, but the precise site and size of the shunt were unclear (). Volume-rendered images from CT during angiography revealed the precise site and size (5 mm) of the arterioportal shunt (). A 5.2-Fr balloon catheter (Selecon MP Catheter II, Cobra type; Terumo Clinical Supply, Gifu, Japan) was inserted into the proper hepatic artery via the right femoral artery. A 2-Fr microcatheter (Cerisier; Medikit, Tokyo, Japan) was then advanced as close as possible to the shunt site. NBCA was mixed with iodized oil (lipiodol) at a ratio of 1:2 to control its polymerization time and to make it radiopaque. The NBCA mixture (0.5 mL) was infused through the microcatheter during flow control in the hepatic artery with a balloon catheter. The hepatic artery was incompletely occluded using a balloon to maintain antegrade blood flow in the hepatic artery (). A small amount of the NBCA mixture leaked into a portal vein during embolization. The arterioportal shunt had completely disappeared after embolization, and the NBCA mixture was found at the shunt site (). Arterial phase CE-CT images obtained after embolization confirmed that the arterioportal shunt had disappeared ().\nAfter embolization of the arterioportal shunt, the esophageal varices decreased in size from F3 to F1. However, the varices were still red in color. Therefore, endoscopic injection sclerotherapy was performed again. Endoscopy performed at 4 months after embolization confirmed that the varices had decreased in size from F3 to F1, and the red color had disappeared (). CE-CT performed at 6 months after embolization showed no evidence of recurrence of an arterioportal shunt, the presence of NBCA mixture at the shunt site in segment 3 of the liver and in the left portal vein, and necrotic lesions caused by RFA ().