Liver Regeneration and Recanalization Time Course following Repeated Reversible Portal Vein Embolization in Swine

Introduction: Portal vein embolization (PVE) is an accepted technique to preoperatively increase the volume of the future remnant liver before major hepatectomy. A permanent material is usually preferred since its superiority to induce liver hypertrophy over absorbable material has been demonstrated. Nevertheless, the use of an absorbable material generates a reversible PVE (RPVE) capable of inducing significant liver hypertrophy. In small animal models, the possibility to proceed to a repeated RPVE (RRPVE) has shown to boost liver hypertrophy further. The aim of this preliminary study was to assess the feasibility and the tolerance of RRPVE in a large animal model, in comparison with permanent PVE (PPVE) and single RPVE.

Methods: Six swine (2 per group) were assigned either to single RPVE group (using powdered gelatin sponge), RRPVE group (2 RPVEs separated by 14 days) or PPVE group (using N-butyl-cyanoacrylate). The feasibility and tolerance of the procedures were evaluated using portography, liver function tests and histological analysis. Evolution of liver volumes was assessed with volumetric imaging by computed tomography.

Results: Embolization of portal branches corresponding to 75% of total liver volume was performed successfully in all animals. Procedures were well tolerated, inducing moderate changes in portal pressure and transient aminotransferase increase. None of the animals developed portal vein thrombosis. After RPVE, complete recanalization occurred at day 11. RRPVE showed a trend for higher hypertrophy, the non-embolized liver to total liver ratio reaching 5.2 ± 1.0% in the RPVE group, 6.8 ± 0.1% in the RRPVE group and 5.0 ± 0.3% in the PPVE group.

Discussion/conclusion: In this preliminary comparative study, RRPVE was as feasible and as well tolerated as the other procedures, and resulted in higher liver hypertrophy.