Is single portal vein perfusion the best approach for machine preservation of liver grafts?

We have read with great interest the article by Schlegel et al., describing a single portal vein approach for hypothermic oxygenated machine perfusion (HOPE) of donation after circulatory death (DCD) liver grafts [1]. It is unquestionable that single portal vein perfusion adds simplicity to liver machine perfusion and may provide protection. However, the main question that needs to be addressed is whether this is the best perfusion technique.