Preoperative portal vein embolization in liver cancer: indications, techniques and outcomes

Abstract

Postoperative liver failure is a severe complication of major hepatectomies, in particular in patients with a chronic underlying liver disease. Portal vein embolization (PVE) is an approach that is gaining increasing acceptance in the preoperative treatment of selected patients prior to major hepatic resection. Induction of selective hypertrophy of the non-diseased portion of the liver with PVE in patients with either primary or secondary hepatobiliary, malignancy with small estimated future liver remnants (FLR) may result in fewer complications and shorter hospital stays following resection. Additionally, PVE performed in patients initially considered unsuitable for resection due to lack of sufficient remaining normal parenchyma may add to the pool of candidates for surgical treatment. A thorough knowledge of hepatic segmentation and portal venous anatomy is essential before performing PVE. In addition, the indications and contraindications for PVE, the methods for assessing hepatic lobar hypertrophy, the means of determining optimal timing of resection, and the possible complications of PVE need to be fully understood before undertaking the procedure. Technique may vary among operators, but cyanoacrylate glue seems to be the best embolic agent with the highest expected rate of liver regeneration for PVE. The procedure is usually indicated when the remnant liver accounts for less than 25-40% of the total liver volume. Compensatory hypertrophy of the non-embolized segments is maximal during the first 2 weeks and persists, although to a lesser extent during approximately 6 weeks. Liver resection is performed 2 to 6 weeks after embolization. The goal of this article is to discuss the rationale, indications, techniques and outcomes of PVE before major hepatectomy.

Keywords: Portal vein embolization (PVE); cyanoacrylate; liver anatomy; liver cancer; surgery.

Figure 1

Schematic illustrates Couinaud segmental liver anatomy and the normal portal venous structures. The possible hepatic resection procedures are also shown. IVC, inferior vena cava; PV, portal vein.

Figure 2

(A,B) Schematics illustrate the normal portal vein (PV) branches from anterior (A) and inferior (B) perspectives. hp, horizontal part; LPV, left portal vein; RPV, right portal vein; up, umbilical (vertical) part.

Figure 3

Schematics illustrate selected variants of the portal venous system. (A) Bifurcation of the right posterior sectoral branch from the left main portal branch, with the right anterior sectoral branch arising from the left main portal branch; (B) portal trifurcation; (C) portal quadrifurcation; (D) bifurcation of the right portal vein (RPV) into anterior (Ant.) and posterior (Post.) branches, which supply segments V/VIII and VI/VII, respectively; (E) complete absence of the RPV. All hepatic segments are supplied by the LPV. hp, horizontal part; LPV, left portal vein; PV, portal vein; up, umbilical (vertical) part.

Figure 4

Right PVE. (A) Portal venogram with a 5-Fr standard catheter placed through a 5-Fr vascular sheath by left-side contralateral approach demonstrates normal subsegmental portal branches; (B) X-ray control after embolization of the right portal vein (RPV) and its branches with a cyanoacrylate glue (Glubran^®2)/Lipiodol mixture in a 1:8 ratio shows radiopaque distribution of embolization material; (C) final portogram reveals that the left portal branches and segment IV veins continue to have blood flow. PVE, portal vein embolization.

Figure 5

Left hepatic lobar hypertrophy in a 40-year-old man with multiple metastases of the right hepatic lobe. (A,B) MRI scans obtained prior to (A) and following (B) PVE of the right portal vein (RPV) show the FLR (segments I, II, III, IV). The FLR/TELV ratio was 16.0% before PVE and 27% after PVE, representing an increase of 11%. The patient subsequently underwent successful right hepatectomy. PVE, portal vein embolization; FLR, future liver remnants; TELV, total estimated liver volume.