When a large portion of the liver must be surgically removed — often to treat liver tumors or metastases from cancers elsewhere in the body — one of the greatest risks is that the remaining liver tissue, called the future liver remnant, may not be large enough to sustain adequate liver function after surgery. Portal vein embolization is a preparatory interventional radiology procedure designed to address exactly this risk, by stimulating the future liver remnant to grow larger before the major resection ever takes place.
Why Does the Size of the Future Liver Remnant Matter So Much?
The liver performs numerous essential functions, and removing too much liver tissue in a single operation can leave an insufficient volume of functioning liver behind, a serious complication generally referred to as post-hepatectomy liver failure. Surgeons and interventional radiologists commonly use volumetric imaging calculations to estimate whether the future liver remnant — the portion of the liver expected to remain after resection — is large enough relative to the patient's body size to safely support them afterward. When calculations suggest the remnant may be borderline or insufficient, portal vein embolization is considered as a way to increase that safety margin before surgery.
How Does Portal Vein Embolization Stimulate Liver Growth?
The liver receives blood through two main sources: the hepatic artery and the portal vein, with the portal vein providing the majority of the liver's blood supply and carrying nutrient-rich blood from the intestines. Portal vein embolization works by occluding the portal vein branches supplying the portion of the liver that is planned for surgical removal, redirecting portal blood flow toward the future liver remnant instead. This increased flow to the remnant is associated with a compensatory growth response, commonly referred to as hypertrophy, in which the remaining liver tissue enlarges over the following weeks.
What Does the Procedure Itself Involve?
Portal vein embolization is typically performed through a percutaneous approach, in which a needle and catheter are advanced into the portal venous system, often through a small puncture in the liver itself under imaging guidance, or in some cases through a transjugular approach. Once catheter access to the relevant portal vein branches is achieved, embolic material — commonly particles, coils, or a combination of embolic agents — is deployed to occlude the branches supplying the segment of liver planned for removal.
How Long Does It Take for the Liver to Grow Before Surgery?
Following portal vein embolization, patients typically undergo repeat volumetric imaging several weeks later to measure the degree of hypertrophy achieved in the future liver remnant. If growth is deemed adequate based on these calculations, surgery proceeds; if growth is insufficient, additional time, or in some cases additional interventional or surgical steps, may be considered. This waiting and re-assessment period is a standard, expected part of the overall treatment pathway rather than a delay or complication.
What Happens if the Future Liver Remnant Does Not Grow Adequately?
In a subset of patients, the future liver remnant does not achieve sufficient hypertrophy after portal vein embolization alone, which may prompt the surgical and interventional team to reassess the overall treatment plan — including exploring additional techniques, adjusting the planned extent of resection, or, in some cases, determining that resection is not safely feasible. This possibility underscores why volumetric reassessment before surgery is considered an essential safety checkpoint rather than a formality.
Embolic Devices Supporting Liver Surgery Preparation
Portal vein embolization depends on embolic devices and catheters capable of selective, controlled occlusion of portal venous branches to redirect flow effectively. INVAMED manufactures a range of embolization technologies used across interventional radiology and hepatobiliary applications; further information is available on the INVAMED embolization products page. Availability and indications vary by country, and the Instructions for Use (IFU) should always be consulted.
Device availability and regulatory status vary by country. Please contact INVAMED or your authorized local distributor for current regulatory information applicable to your region.