The significance of the right hepatic artery originating from the superior mesenteric artery in patients with cavernous transformation of the portal vein.

PURPOSE Dilatation of the hepatic artery in response to decrease in portal vein flow is known as hepatic arterial buffer response (HABR). In this study, the effect of HABR on variant hepatic arterial anatomy is investigated by analyzing the frequency of the right hepatic artery originating from the superior mesenteric artery (variant artery) and by determining the diameters of variant artery and common hepatic artery (CHA) in patients with cavernous transformation of the portal vein. MATERIALS AND METHODS Forty-one patients who were referred for contrast-enhanced abdominal magnetic resonance angiography were retrospectively evaluated in two groups: group 1 (n = 15), cirrhotic patients with cavernous transformation of the portal vein; and group 2 (n = 26), cirrhotic patients without cavernous transformation of the portal vein. RESULTS The frequency of the variant artery was significantly higher (53%) in patients with cavernous transformation of the portal vein (P < 0.01) than those without cavernous transformation (11.5%). The mean diameters of the CHA and the variant artery in 2 groups were not significantly different. CONCLUSION Vasodilatation at the level of intrahepatic arterioles (HABR) in response to diminished portal flow may be a factor that increases the frequency of the variant hepatic artery.