How should liver hypertrophy be stimulated?A comparison of upfront associating liver partition and portal vein ligation for staged hepatectomy(ALPPS)and portal vein embolization(PVE)with rescue possibility

Background:The role of associating liver partition and portal vein ligation for staged hepatectomy(ALPPS)in comparison to portal vein embolization(PVE)is debated.The aim of this study was to compare successful resection rates(RR)with upfront ALPPS vs.PVE with rescue ALPPS on demand and to compare the hypertrophy of the liver between ALPPS and PVE plus subsequent rescue ALPPS.Methods:A retrospective analysis of all patients treated with PVE for colorectal liver metastasis(CRLM)or ALPPS(any diagnosis,rescue ALPPS included)at five Scandinavian university hospitals during the years 2013-2016 was conducted.A Chi-square test and a Mann-Whitney U test were used to assess the difference between the groups.A successful RR was defined as liver resection without a 90-day mortality.Results:A total of 189 patients were included.Successful RR was in 84.5%of the patients with ALPPS upfront and in 73.3%of the patients with PVE and rescue ALPPS on demand(P=0.080).The hypertrophy of the future liver remnants(FLRs)with ALPPS upfront was 71%(48-97%)compared to 96%(82-113%)after PVE and rescue ALPPS(P=0.010).Conclusions:Upfront ALPPS offers a somewhat higher successful RR than PVE with rescue ALPPS on demand.The sequential combination of PVE and ALPPS leads to a higher overall degree of hypertrophy than upfront ALPPS.