Regeneration of the un-embolized liver parenchyma following portal vein embolization

Background/Aims: Portal vein embolization (PVE) induces atrophy of the embolized hepatic parenchyma and hypertrophy of the un-embolized liver. It is important to predict hypertrophy of un-embolized liver following PVE to decide a subsequent tactics in patients with liver tumors. The hypertrophy following PVE was evaluated in reference to embolized liver volume and a preceding use of transcatheter hepatic arterial chemoembolization (HACE) in this study. Methods: Thirty patients with liver tumors were studied. PVE was performed transhepatically. Ethanol (15–65 ml) was injected into portal veins, which perfused the liver segment bearing the tumor until occlusion. Embolization was performed at subsegmental portal branches in five patients, segmental branches in 11 patients and right portal veins in 14 patients. Twenty-three patients with underlying chronic liver disease and hepatocellular carcinoma (HCC) underwent PVE 2–6 weeks after HACE. The remaining seven patients without underlying chronic liver disease had bile duct cancer (6) or liver metastasis (1), and underwent PVE alone. Segmental volume in the liver was measured with computed tomography before and 4 weeks after PVE. Results: The degree of hypertrophy showed a significant correlation with embolized liver volume (r=0.685, p<0.001). Increase in un-embolized liver volume was 2.4±5.8% with subsegmental embolization (NS), 15.2±6.4% with segmental embolization (p<0.01) and 46.5±18.8% with right PVE (p<0.001). In 14 patients with right PVE, degree of hypertrophy in seven patients with HACE was greater than that in seven patients without HACE (56.7±21.6% vs 36.4±7.4%; p<0.03). Conclusions: Hypertrophy of the un-embolized liver parenchyma following PVE was correlated with embolized liver volume and was augmented with combined use of HACE.