Segment 4 occlusion in portal vein embolization increase future liver remnant hypertrophy - A Scandinavian cohort study.

<bold>Background: </bold>The additional value of including segment 4 (S4) portal branches in right portal vein embolization (rPVE) is debated. The aim of the study was to explore this in a large multicenter cohort.<bold>Material and Methods: </bold>A retrospective cohort study consisting of all patients subjected to rPVE from August 2012 to May 2017 at six Scandinavian university hospitals. PVE technique was essentially the same in all centers, except for the selection of main embolizing agent (particles or glue). All centers used coils or particles to embolize S4 branches. A subgroup analysis was performed after excluding patients with parts of or whole S4 included in the future liver remnant (FLR).<bold>Results: </bold>232 patients were included in the study, of which 36 received embolization of the portal branches to S4 in addition to rPVE. The two groups (rPVE vs rPVE + S4) were similar (gender, age, co-morbidity, diagnosis, neoadjuvant chemotherapy, bilirubin levels prior to PVE and embolizing material), except for diabetes mellitus which was more frequent in the rPVE + S4 group (p = 0.02). Pre-PVE FLR was smaller in the S4 group (333 vs 380 ml, p = 0.01). rPVE + S4 resulted in a greater percentage increase of the FLR size compared to rPVE alone (47 vs 38%, p = 0.02). A subgroup analysis, excluding all patients with S4 included in the FLR, was done. There was no longer a difference in pre-PVE FLR between groups (333 vs 325 ml, p = 0.9), but still a greater percentage increase and also absolute increase of the FLR in the rPVE + S4 group (48 vs 38% and 155 vs 112 ml, p = 0.01 and 0.02).<bold>Conclusion: </bold>In this large multicenter cohort study, additional embolization of S4 did demonstrate superior growth of the FLR compared to standard right PVE. [ABSTRACT FROM AUTHOR]