Portal vein embolization

Portal vein embolisation (PVE) is a technique used to selectively occlude the blood supply to one of the liver lobes, diverting portal blood flow to the other lobe, allowing thisthe future liver remnant (FLR). This diversion will increase the size of the post hepatectomy future liver remnant (FLR) and increased size of the FLR improves surgical outcomes by preventing liver insufficiency.

PVE is a procedure performed by interventional radiology.

History

First published in 1990 by Makuuchi et al. ²

Indications

• FLR that would be too small for the patient's body mass, post hepatectomy (typically <20%)
• elevated ICG-R15 serum values 15 minutes after injection
  • ICG (indocyanine green) binds to albumin and is excreted by the biliary system
  • elevated values imply decreased hepatic reserve
• patients who underwent hepatotoxic chemotherapy, if FLR<30%
• cirrhosis, Child-Pugh class A, ICG-R15 <10%, if FLR <40%
• patients with hepatic steatosis
• concomitant pancreas resection and patients with diabetes due to poor post-hepatectomy hypertrophy rates

Contraindications

• ipsilateral portal tumour thrombus precluding catheter placement 
• clinically overt portal hypertension  (procedure exacerbates portal hypertension)

Procedure

Can be performed on an outpatient basis. The FLR (on CT or MRI) should be obtained prior undertaking this procedure.

Technique

The right lobe is almost always targeted.  The approach is usually through the right lobe, as well.

Different embolic agents have been used, including:

• n-butyl cyanoacrylate (NBCA)
• ethiodized oil
• fibrin glue
• ethanol
• microparticles (such as polyvinyl alcohol, PVA)
• microspheres followed by coils are used by some.

The portal vein can be approached surgically through a transileocolic approach, but interventional radiology usually approaches the portal vein transhepatically.  Portal vein pressures are checked pre-procedure, to ensure that there is no portal hypertension.

Postprocedural care

• minor fluctuations in postprocedure liver function tests (50%)
• liver synthetic functions usually not affected
• nausea, fever, and pain are rare

Complications

• reported 0% procedure-related mortality ³
• reported overall morbidity of 2.2% ³
• nontarget embolization
• complete portal vein thrombus
• risks similar to other transhepatic procedures
  • hemobilia
  • hemoperitoneum
  • cholangitis
  • subcapsular hematoma
  • pneumothorax

Outcomes

Patients with otherwise normal livers regenerate two weeks postprocedure at 12-21 cm³ / day (9 cm³ / day for cirrhotic patients) ⁵. 2-4 weeks is usually enough for most patients with normal liver function (>4 weeks for patients with cirrhosis).