When a live transplant patient receives a small volume of graft, the postoperative liver function is not optimal. This is described as small-for-size live syndrome (SFSS), SFSS is a recognizable clinical condition after major liver surgery (transplantation & resection), characterised by postoperative liver dysfunction/failure. Overcoming this condition will allow us to transplant smaller livers into larger patients without major complications. This will encourage living donors to donate a smaller part of their liver to their sick relative with less risk to the donor, as well as a good outcome for the recipient. This study aims to understand the mechanism of the condition. This research assesses the relationship between portal pressure and the outcome of major live surgery , which might lead to the modification of surgical techniques in order to overcome SFSS.