Portal Vein Embolization

Abstract

Portal vein embolization (PVE) is used to increase the volume of normal liver tissue, allowing resection of liver malignancy in patients with an insufficient future liver remnant (FLR). PVE is recommended when FLR <20% in normal liver, FLR <30% in liver pretreated with more than 3 months of chemotherapy, and FLR <40% in the cirrhotic liver. Embolization of the right or left portal vein branch causes atrophy of the ipsilateral liver and hypertrophy of the contralateral liver. Right PVE is the most common procedure, as the volume usually favors the right side of the liver. Embolization of segment 4 portal vein branches has proven feasible and effective, in addition to right PVE, to increase regeneration in patients requiring an extended right hepatectomy. Percutaneous transhepatic ipsilateral PVE is the preferred approach, which is safe, with low rates of complications and mortality. We encourage the use of standardized FLR (sFLR) to determine the need for PVE and when measuring the effect of PVE. sFLR is calculated by dividing the measured FLR, determined by contrast-enhanced CT, by the total estimated liver volume (TEL). TEL is calculated based on the BSA. The percent of regeneration can be termed the degree of hypertrophy (DH). The DH divided by the number of weeks can be termed the kinetic growth rate (KGR), and is a functional measurement of the regenerative capacity of the liver. Both are useful predictors when assessing risk of postoperative hepatic insufficiency.