Portal vein embolisation

Portal vein embolization (PVE) is a preoperative procedure designed to enhance liver regeneration before major liver surgery, particularly in patients undergoing hepatectomy (removal of part of the liver) for liver cancer or metastases. The primary goal of PVE is to increase the size and function of the future liver remnant (FLR) – the portion of the liver that will remain after surgery. Here’s an in-depth overview of the procedure:

Procedure Overview

1. Pre-procedure Evaluation:
   • Imaging: MRI, CT scans, or ultrasound to assess the liver’s anatomy and the tumor’s location.
   • Liver Function Tests: To evaluate the current function of the liver and ensure the patient can tolerate the procedure.
2. Procedure Preparation:
   • Anesthesia: Usually performed under local anesthesia with sedation.
   • Access: A small incision is made to access the portal vein, typically through the skin using ultrasound or CT guidance.
3. Embolization Process:
   • Catheter Placement: A catheter is inserted through the incision and guided into the portal vein branch that supplies the liver lobe or segment to be resected.
   • Embolic Agents: Embolic materials (such as polyvinyl alcohol particles, microspheres, or coils) are injected through the catheter to block the blood flow to the targeted part of the liver.
4. Induction of Hypertrophy:
   • Liver Regeneration: By embolizing the portal vein branch, blood flow is redirected to the remaining liver segments, stimulating hypertrophy (growth) of the future liver remnant.

Benefits

• Enhanced Liver Regeneration: Promotes the growth of the remaining liver segments, increasing the volume and function of the future liver remnant.
• Improved Surgical Outcomes: Reduces the risk of postoperative liver failure by ensuring adequate liver function after resection.
• Minimally Invasive: Compared to other surgical interventions, PVE is less invasive with a shorter recovery time.

Indications

• Liver Cancer: Patients with hepatocellular carcinoma (HCC) or cholangiocarcinoma who require major liver resection (Click here to read more on Hepatocellular Carcinoma)
• Metastatic Cancer: Patients with liver metastases from colorectal cancer or other primary cancers that need significant liver resection.
• Insufficient Future Liver Remnant: Patients whose remaining liver volume is deemed inadequate for safe resection without prior hypertrophy.

Risks and Considerations

• Post-embolization Syndrome: Symptoms such as pain, fever, and nausea after the procedure.
• Non-target Embolization: Risk of embolic agents affecting non-target areas, causing unintended damage.
• Liver Dysfunction: Temporary impairment of liver function due to the procedure.
• Infection: Risk of infection at the catheter insertion site or within the liver.

Post-Procedure Care

• Monitoring: Regular imaging (CT or MRI) to assess the growth of the future liver remnant.
• Symptom Management: Medications to manage pain, fever, and other side effects.
• Liver Function Tests: Ongoing assessment of liver function through blood tests.

Comparison with Other Techniques

• PVE vs. Two-stage Hepatectomy: PVE can be an alternative to a two-stage hepatectomy, where the first stage involves partial resection followed by a period of liver regeneration before completing the resection.
• PVE vs. ALPPS: Associating Liver Partition and Portal vein Ligation for Staged hepatectomy (ALPPS) is another approach that induces rapid liver hypertrophy but carries higher risks compared to PVE.

Clinical Outcomes

• Efficacy: PVE is effective in inducing hypertrophy of the future liver remnant in the majority of patients.
• Surgical Success: Increases the feasibility and safety of major liver resections, improving surgical outcomes and patient survival rates.

Portal vein embolization is a crucial preparatory procedure for patients requiring extensive liver surgery. By promoting liver regeneration, PVE enhances the safety and efficacy of subsequent liver resections, making it an important tool in the management of liver cancers and metastases.