Indications & Patient Selection
Goal of PVE
Induce hypertrophy of the future liver remnant (FLR) before major hepatectomy by embolizing portal venous inflow to the lobe slated for resection, redirecting portal blood to the FLR and stimulating regeneration. Success prevents post-hepatectomy liver failure (PHLF), the most feared perioperative complication of major resection.
FLR Thresholds for PVE Indication
| Liver Status | PVE Indicated When FLR < | Rationale |
|---|---|---|
| Normal liver | 20–25% of TLV | Healthy parenchyma regenerates well; lower threshold acceptable |
| Chemotherapy-treated / steatosis | 30% of TLV | Hepatotoxic injury impairs regenerative capacity |
| Cirrhosis (Child-Pugh A) | 40% of TLV | Chronic liver disease significantly limits regeneration |
Degree of Hypertrophy (DH) — Surgical Go/No-Go
- DH ≥5% TLV at 4–6 weeks after PVE = adequate hypertrophy → proceed with hepatectomy
- DH <5% = poor hypertrophy = high PHLF risk → reassess; consider ALPPS
- KGR (Kinetic Growth Rate) = DH (%) / time (weeks); KGR >2%/week = adequate; <2%/week = consider surgical alternatives
- Mean FLR volume increase in literature: 37.9% following PVE (van Lienden et al. 2013 systematic review)
Contraindications
- Portal hypertension with varices — PVE could worsen portal hypertension; variceal hemorrhage risk
- Extensive portal venous tumor thrombus — thrombus already redirects flow to FLR; additional PVE risks non-target FLR embolization
- FLR portal vein occlusion — no viable FLR to hypertrophy
- Not a presurgical candidate — PVE has no benefit if hepatectomy will not proceed
- INR >1.5 uncorrectable — transhepatic access unsafe
- Relative: intrahepatic biliary dilation in FLR; extrahepatic metastatic disease; renal insufficiency
Preprocedural Workup
- CT volumetry (thin-slice 1–2 mm) to measure FLR and TLV; MRI acceptable alternative
- FLR% = FLR volume / (TLV − tumor volume) × 100 — standardized FLR (sFLR)
- Liver function tests: Child-Pugh score, MELD, bilirubin, albumin, INR
- ICG (indocyanine green) clearance test at specialized centers for functional reserve assessment
- Multidisciplinary planning: define resection extent with hepatobiliary surgery before PVE
Pre-Procedure Checklist
Access & Equipment
- Ipsilateral transhepatic approach (same side as resection): right-sided PVE uses right portal vein access; avoids FLR injury during access and sheath manipulation
- 21G micropuncture set for initial portal vein access
- 5–6 Fr vascular sheath
- 5 Fr flush catheter (pigtail) for initial portogram
- Microcatheter (3 Fr) for selective embolization of segmental branches
- Reverse-curve catheter (Simmons 1 or 2, SOS Omni 2) for right portal vein selection from ipsilateral access
Embolic Agents
- NBCA (N-butyl cyanoacrylate) + Lipiodol 1:4 dilution — gold standard; permanent; most durable; highest rate of FLR hypertrophy
- PVA particles 300–500 µm + coils — acceptable; particles until stasis, then coils proximally; risk of partial recanalization before surgery
- Gelfoam slurry — alternative; temporary; rarely used as sole agent for PVE
- Amplatz vascular plugs; thrombin; fibrin glue — described as adjuncts
Relevant Anatomy
Portal Vein Branching
- Main portal vein (MPV) → bifurcates into right and left portal veins at porta hepatis
- Right portal vein → right anterior sector (segments V, VIII) + right posterior sector (segments VI, VII)
- Left portal vein → segment IV branches + left lateral sector (segments II, III) + caudate (segment I)
- Right lobe (segments V–VIII): typically resected in right hepatectomy; these are the PVE targets
- FLR for standard right hepatectomy: segments I, II, III, IV (left lobe alone ≈30% TLV in most patients)
Extended Right Hepatectomy Considerations
- Extended right hepatectomy removes right lobe plus segment IV → FLR = only segments II–III (≈20% TLV)
- Segment IV branches arise from left PV; must be embolized separately for extended right hepatectomy to maximize left lobe (II–III) hypertrophy
- Caudate lobe (segment I): dual portal supply; embolize caudate branches separately if caudate included in resection
- Common variant: trifurcation of main PV (right anterior, right posterior, and left PV arising together) — plan portogram carefully to avoid mistaking for bifurcation
FLR Calculation
TLV (Total Liver Volume) can be estimated from body surface area: TELV = −791.41 + 1,267.28 × BSA (Vauthey et al. Liver Transpl 2002). Preferred method is direct volumetric tracing on thin-slice CT (1–2 mm) or MRI. Exclude tumor volume from denominator to obtain standardized FLR ratio.
Step-by-Step Technique
US-Guided Transhepatic Portal Vein Access
Flush Portogram
Segment IV Embolization (if Extended Right Hepatectomy)
Selective Right Portal Vein Catheterization
NBCA-Lipiodol Embolization — Right Anterior Sector (V, VIII)
NBCA-Lipiodol Embolization — Right Posterior Sector (VI, VII)
Final Portogram — Confirm Occlusion
Sheath Removal & Tract Management
Post-PVE: CT Volumetry at 4–6 Weeks
Community Cards
Fluoroscopic Landmarks
Portogram Anatomy
- Right anterior portal vein: supplies segments V (anterior inferior) and VIII (anterior superior); typically courses anteriorly and superiorly from right PV
- Right posterior portal vein: supplies segments VI (posterior inferior) and VII (posterior superior); courses posteriorly
- Left PV: opacifies on portogram and runs to the left — do NOT embolize in standard right hepatectomy
- On AP projection: right PV branches spread right-ward and inferiorly; left PV arches superiorly toward left side of the liver
NBCA Cast Appearance
- Radiopaque branching cast: Lipiodol in the NBCA mixture renders the embolized portal branches opaque on fluoroscopy — visualized as a dense, arborizing cast filling the portal branches
- Cast is permanent and persists on all subsequent imaging (CT, fluoroscopy)
- Appearance confirms successful embolization; compare to pre-embolization portogram for completeness
- Gelfoam or coils: coils appear as metallic densities; Gelfoam appears as faint contrast stain in parenchyma
If NBCA is seen flowing retrograde toward the left portal vein during injection, stop immediately. Flush catheter with D5W (glucose prevents NBCA polymerization in catheter). Reposition microcatheter more distally before resuming injection. Embolization of the FLR portal vein = procedure failure and potential surgical cancellation.
Segment IV Catheterization Landmark
- Segment IV branches arise from the horizontal (transverse) portion of the left PV
- On AP portogram: segment IV branches course anteriorly and superiorly between the left and right lobes (roughly in the plane of the gallbladder fossa)
- Catheterize segment IV from the left PV origin using microcatheter; confirm selective position before NBCA injection
Completion Portogram Checklist
- All right anterior sector branches: no flow, replaced by NBCA cast
- All right posterior sector branches: no flow, cast present
- Segment IV (if extended right): cast visible, no flow
- Left PV: fully patent with normal opacification of segments II–III
- Main PV: patent; no thrombosis; no non-target embolization
Troubleshooting
NBCA Solidifies in Catheter or Before Filling Target Vessels
Increase Lipiodol ratio to 1:5 or 1:6 (more Lipiodol = slower polymerization). Ensure catheter is flushed with D5W (not saline) before and after NBCA injection — saline and blood both accelerate polymerization. Keep catheter dead space minimal by using microcatheter distally. Work quickly: prepare NBCA immediately before injection. Acetic acid can be added to the NBCA to slow polymerization if needed.
NBCA Reflux Toward Left Portal Vein During Injection
Stop injection immediately if any retrograde NBCA flow is observed fluoroscopically. Flush microcatheter with D5W to prevent catheter adherence and NBCA advancement. Wait for any NBCA in the catheter to clear. Reposition microcatheter more distally into the target vessel before resuming. Use smaller volume injections. Ensure catheter tip is in a stable, wedged position to prevent reflux. Consider repositioning to a more distal branch.
Right Portal Vein Cannot Be Accessed via Ipsilateral Approach
Consider switching to the contralateral approach: access left PV via left transhepatic puncture (segment 3 branch under ultrasound guidance). From the left, right and segment IV portal veins are easier to select due to favorable angulation and shorter catheter length requirement. Main disadvantage is risk of FLR injury during access — proceed carefully with 21G needle and minimize sheath size. Contralateral PVE is technically feasible with comparable outcomes.
DH <5% or KGR <2%/week at 4–6 Weeks
First confirm embolization was complete on CT volumetry — check for any residual right portal vein patency or recanalization (more common with PVA than NBCA). If recanalization found: repeat PVE. If embolization appears complete and DH is still inadequate: discuss with hepatobiliary surgery regarding ALPPS (Associating Liver Partition and Portal vein ligation for Staged hepatectomy) — surgical in-situ liver splitting achieves hypertrophy in 7–14 days but carries higher morbidity than staged PVE + resection. Also reassess disease burden for interval progression.
NBCA Does Not Solidify Adequately in Vessel
Decrease Lipiodol ratio (increase NBCA concentration, e.g., 1:3). Add acetic acid to accelerate polymerization. Ensure the microcatheter is placed far enough distally that there is minimal portal vein flow washing NBCA proximally before it sets. Inject in a slow, controlled bolus to maintain contact with vessel wall.
Complications
Procedure-Specific Complications
- Non-target embolization of FLR portal vein (<1%) — most feared; inadvertent embolization of left PV or its branches; FLR damaged = surgery must be canceled; prevention requires meticulous NBCA injection technique with continuous fluoroscopic monitoring
- Complete main portal vein thrombosis (<2%) — rare; anticoagulation if occurs; may resolve spontaneously; can arise from NBCA propagation into MPV; monitor with Doppler ultrasound post-procedure
- Recanalization of embolized branches — more common with PVA + coils than NBCA; if found on follow-up CT = repeat PVE before scheduling surgery
Access & Transhepatic Complications
- Access site hemorrhage / hemobilia — most common complication; usually self-limiting; transhepatic track tamponades with parenchyma; Gelfoam tract embolization on sheath removal reduces risk; rarely requires embolotherapy
- Subcapsular hematoma — from access needle; usually small and self-limited; monitor with post-procedure imaging
- Sepsis / hepatic abscess — rare; sterile technique and prophylactic antibiotics mandatory; increased risk in biliary obstruction or prior biliary manipulation
- Pneumothorax — rare; upper approach through pleural space; post-procedure CT confirms
Post-Embolization Syndrome & Oncologic Considerations
- Post-embolization syndrome — mild; low-grade fever, RUQ pain, nausea; resolves in 3–5 days; NSAIDs and antiemetics; prophylactic antibiotics at time of procedure; same-day or next-day discharge in most patients
- Tumor stimulation hypothesis (debated) — PVE may theoretically stimulate growth of contralateral (FLR-side) tumor deposits through increased portal flow and growth factors; significance disputed in literature; implication: schedule surgery within 4–6 weeks of PVE without unnecessary delay
- Resection cancellation rate — approximately 20% of planned resections are ultimately canceled following PVE; causes include tumor progression (6.1%), extrahepatic metastases (8.1%), and PVE-specific complications or inadequate hypertrophy (4.5%) per van Lienden 2013 meta-analysis
Overall Safety Profile (Literature)
- Technical success rate: 99.3%
- Clinical success rate (adequate FLR hypertrophy): 96.1%
- Major complications: approximately 2.5%
- Mortality: 0.1%
- No statistically significant difference in complication rate between ipsilateral and contralateral approach
Critical Pearls
CT volumetry with thin slices (1–2 mm) is mandatory. FLR <20% in a normal liver = PVE mandatory before major resection; attempting surgery without PVE in this setting carries unacceptable PHLF risk. If the surgeon disputes volumetry results, refer the patient to the hepatobiliary MDT for consensus before proceeding. Standardized FLR (sFLR) = FLR volume / (TLV − tumor volume) × 100 — always subtract tumor volume from the denominator.
Embolic durability matters because surgery is deferred 4–6 weeks. PVA particles + coils may partially recanalize within that window, allowing portal flow to return to the embolized lobe and reducing the hypertrophic stimulus. NBCA-Lipiodol creates a permanent polymerized cast that does not recanalize. Studies report greater FLR volume increase with NBCA vs. particles. NBCA is the gold standard embolic agent for PVE at centers with the expertise to handle it.
Extended right hepatectomy removes right lobe + segment IV, leaving only segments II–III as the FLR (≈20% TLV). To maximally hypertrophy segments II–III, segment IV portal branches must be embolized in addition to all right portal branches. Failure to include segment IV results in persistent portal flow to IV and inadequate stimulus for left lateral sector growth. Embolize segment IV branches first (before right PV) to simplify the procedure sequence.
Hepatic hypertrophy peaks in the 2 weeks following PVE and plateaus by 3 weeks. However, 4–5 weeks allows greater final volume and is the standard follow-up interval for patients with normal livers; 4–5 weeks is also used for patients with chronic liver disease (impaired regeneration). Waiting longer than 6 weeks risks disease progression and potential new metastases in the FLR that would cancel surgery. Schedule CT volumetry at exactly 4 weeks for normal liver.
ALPPS (Associating Liver Partition and Portal vein ligation for Staged hepatectomy) is a two-stage surgical technique: Stage 1 = in situ liver splitting + portal vein ligation; Stage 2 = completion hepatectomy 7–14 days later after rapid hypertrophy. ALPPS achieves faster and greater FLR hypertrophy than PVE alone but carries significantly higher morbidity and mortality than PVE + staged resection. Reserve ALPPS for: PVE failure (DH <5%), time pressure from rapid tumor progression, or anatomical situations where PVE is technically infeasible.
KGR = DH (%) / time (weeks). KGR >2%/week = adequate hypertrophy, proceed with surgery. KGR <2%/week = inadequate response, consider ALPPS or reassess. Measure at 2 weeks and again at 4 weeks to establish trajectory. An early KGR at 2 weeks allows surgical planning adjustment (escalate to ALPPS sooner if KGR is already <2%/week) rather than waiting 4–6 weeks to discover inadequate hypertrophy. Note: cirrhotic livers will have lower KGR by nature — adjust expectations accordingly.
References & Resources
Key Outcomes Data
- Technical success: 99.3%; clinical success: 96.1%; major complications: 2.5%; mortality: 0.1% (van Lienden et al. Cardiovasc Intervent Radiol 2013 — systematic review)
- Mean FLR volume increase: 37.9 ± 0.1% following PVE
- 20% of planned resections ultimately canceled post-PVE (tumor progression, extrahepatic disease, insufficient hypertrophy)
- NBCA associated with greater FLR volume increase vs. particles in multiple series
- No statistically significant difference in complications between ipsilateral and contralateral access approach
Primary References
- Hsu SL, Kalva SP. Portal Vein Embolization. In: Faintuch S, Salazar GM, eds. Interventional Radiology Techniques in Ablation, Transcatheter Therapy, and Biopsy. Thieme; 2016: Ch. 12 (pp. 182–188).
- Abdalla EK, Barnett CC, Doherty D, Curley SA, Vauthey JN. Extended hepatectomy in patients with hepatobiliary malignancies with and without preoperative portal vein embolization. Arch Surg. 2002;137(6):675–680.
- Vauthey JN, Abdalla EK, Doherty DA, et al. Body surface area and body weight predict total liver volume in Western adults. Liver Transpl. 2002;8(3):233–240.
- van Lienden KP, van den Esschert JW, de Graaf W, et al. Portal vein embolization before liver resection: a systematic review. Cardiovasc Intervent Radiol. 2013;36(1):25–34.
- Madoff DC, Abdalla EK, Vauthey JN. Portal vein embolization in preparation for major hepatic resection: evolution of a new standard of care. J Vasc Interv Radiol. 2005;16(6):779–790.
- May BJ, Madoff DC. Portal vein embolization: rationale, technique, and current application. Semin Intervent Radiol. 2012;29(2):81–89.
- Farges O, Belghiti J, Kianmanesh R, et al. Portal vein embolization before right hepatectomy: prospective clinical trial. Ann Surg. 2003;237(2):208–217.
- Nagino M, Kamiya J, Nishio H, et al. Two hundred forty consecutive portal vein embolizations before extended hepatectomy for biliary cancer. Ann Surg. 2006;243(3):364–372.