Purpose: To retrospectively evaluate the prevalence of extrahepatic collateral artery supply to tumor thrombi of hepatocellular carcinomas (HCCs) invading the inferior vena cava (IVC) and to assess the determining factors.
Materials and methods: From February 1998 to June 2007, 82 patients with IVC tumor thrombi on computed tomography (CT) underwent angiographic evaluation of their extrahepatic collateral artery supply. Potential determining factors for extrahepatic collateral artery supply to the IVC tumor thrombi included sex, age, Child-Pugh class, history of chemoembolization, tumor factors (ie, size, number, and growth pattern), distance from primary tumor to IVC thrombi, portal vein invasion, and extent of IVC thrombi (ie, occupying more than half the IVC lumen on transverse CT image, completely filling and distending IVC lumen, or extending into the right atrium). Univariate analysis and multiple logistic regression analysis were performed.
Results: Fifty-four of the 82 patients (65.9%) had extrahepatic collateral artery supply: 47 from the right inferior phrenic artery, four from the right adrenal artery, two from the right internal mammary artery, and one from the right renal artery. The presence of extrahepatic collateral artery supply to IVC tumor thrombi showed a significant relationship with a history of chemoembolization (P = .001, odds ratio [OR] = 22.4) and distension of IVC by tumor thrombi (P = .005, OR = 9.1).
Conclusions: IVC tumor thrombi of HCCs are frequently supplied by extrahepatic collateral arteries, the most common of which is the right inferior phrenic artery. The significant determining factors are a history of chemoembolization and the extent of IVC tumor thrombi.