Portal Vein Embolization before Right Hepatectomy: Improved Results Using n-Butyl-Cyanoacrylate Compared to Microparticles Plus Coils

Image-guided percutaneous strategies to improve the resectability of HCC: Portal vein embolization, liver venous deprivation, or radiation lobectomy?

Despite considerable advances in surgical technique, many patients with hepatic malignancies are not operative candidates due to projected inadequate hepatic function following resection. Consequently, the size of the future liver remnant (FLR) is an essential consideration when predicting a patient's likelihood of liver insufficiency following hepatectomy. Since its initial description 30 years ago, portal vein embolization has become the standard of care for augmenting the size and function of the FLR preoperatively. However, new minimally invasive techniques have been developed to improve surgical candidacy, chief among them liver venous deprivation and radiation lobectomy. The purpose of this review is to discuss the status of preoperative liver augmentation prior to resection of hepatocellular carcinoma with a focus on these three techniques, highlighting the distinctions between them and suggesting directions for future investigation.

CIRSE Standards of Practice on Portal Vein Embolization and Double Vein Embolization/Liver Venous Deprivation

This CIRSE Standards of Practice document is aimed at interventional radiologists and provides best practices for performing liver regeneration therapies prior to major hepatectomies, including portal vein embolization, double vein embolization and liver venous deprivation. It has been developed by an expert writing group under the guidance of the CIRSE Standards of Practice Committee. It encompasses all clinical and technical details required to perform liver regeneration therapies, revising the indications, contra-indications, outcome measures assessed, technique and expected outcomes.

Balloon-Assisted Portal Vein Embolization Using n-Butyl-2-Cyanoacrylate-Lipiodol-Iopamidol Mixture in Swine: A Comparison of 2 Formulations

PURPOSE

To compare 2 ratios of n-butyl-2-cyanoacrylate (nBCA)-ethiodized oil (Lipiodol)-iopamidol (NLI) in balloon-assisted portal vein embolization (PVE) in swine.

MATERIALS AND METHODS

In an in vitro study, NLI prepared at a ratio of 2:3:1 (NLI231) or 1:4:1 (NLI141) was injected into 2.5- or 10-mL syringes filled with swine blood, and the viscosity of NLI was measured to determine an appropriate balloon occlusion time. Two portal vein branches in 8 female swine (n = 16 vein branches) were embolized with NLI231 (n = 8) or NLI141 (n = 8) under balloon occlusion. Portal venography was performed before, immediately after, and 3 days after PVE to evaluate the migration of NLI and the recanalization of embolized portal vein branches. Then, the livers were removed for histopathologic evaluation.

RESULTS

The times to peak viscosity of NLI231 in the 2.5- and 10-mL syringes were 55.8 seconds (SD ± 7.0) and 85.2 seconds (SD ± 6.3), and those to peak viscosity of NLI141 were 129.2 seconds (SD ± 11.8) and 254.0 seconds (SD ± 21.8), respectively. No migration of NLI231 was observed in all 8 procedures immediately or 3 days after PVE. Migration of NLI141 was observed in 6 of 8 procedures within 3 days after PVE. The migration frequency of the embolic material was lower in the NI231 group than in the NLI141 group (0/8 vs 6/8; P = .051). Histologically, NLI231 occupied the portal veins without any thrombi, whereas NLI141 was accompanied by thrombi in the portal veins.

CONCLUSIONS

NLI231 may be more suitable than NLI141 for balloon-assisted PVE in swine.

Hepatic Hypertrophy in Normal and Cirrhotic Livers Following Portal Vein Embolization: Comparative Assessment of 2 Different Embolic Regimens in a Large Animal Model

PURPOSE

To compare the mechanistic effects and hypertrophy outcomes using 2 different portal vein embolization (PVE) regimens in normal and cirrhotic livers in a large animal model.

METHODS AND MATERIALS

The Institutional Animal Care and Use Committee approved all experiments conducted in this study. Fourteen female Yorkshire pigs were separated into a cirrhotic group (CG, n = 7) and non-cirrhotic group (NCG, n = 7) and further subgrouped into those using microspheres and coils (MC, n = 3) or n-butyl cyanoacrylate (nBCA, n = 3) and their corresponding controls (each n = 1). A 3:1 ethiodized oil and ethanol mixture was administered intra-arterially in the CG to induce cirrhosis 4 weeks before PVE. Animals underwent baseline computed tomography (CT), PVE including pre-PVE and post-PVE pressure measurements, and CT imaging at 2 and 4 weeks after PVE. Immunofluorescence stainings for CD3, CD16, Ki-67, and caspase 3 were performed to assess immune cell infiltration, hepatocyte proliferation, and apoptosis. Statistical significance was tested using the Student's t test.

RESULTS

Four weeks after PVE, the percentage of future liver remnant (FLR%) increased by 18.8% (standard deviation [SD], 3.6%) vs 10.9% (SD, 0.95%; P < .01) in the NCG vs CG. The baseline percentage of standardized future liver remnant (sFLR%) for the controls were 41.6% for CG vs 43.6% for NCG. Based on the embolic agents used, the sFLR% two weeks after PVE was 58.4% (SD, 3.7%) and 52.2% (SD, 0.9%) (P < .01) for MC and 46.0% (SD, 2.2%) and 47.2% (SD, 0.4%) for nBCA in the NCG and CG, respectively. Meanwhile, the sFLR% 4 weeks after PVE was 60.5% (SD, 3.9%) and 54.9% (SD, 0.8%) (P < .01) and 60.4% (SD, 3.5%) and 54.2% (SD, 0.95%) (P < .01), respectively. Ki-67 signal intensity increased in the embolized lobe in both CG and NCG (P < .01).

CONCLUSIONS

This preclinical study demonstrated that MC could be the preferred embolic of choice compared to nBCA when a substantial and rapid FLR increase is needed for resection, in both cirrhotic and non-cirrhotic livers.

Portal vein embolization with N-butyl-cyanoacrylate improves liver hypertrophy compared to microparticles - A Swedish multicenter cohort study

Background

An adequate future liver remnant (FLR) is fundamental for major liver resections. To achieve sufficient FLR, portal vein embolization (PVE) may be used. The most effective material for PVE has yet to be determined. The aim of this study was to investigate the differences in FLR growth between n-butyl-cyanoacrylate glue (NBCA) and microparticles.

Material/methodsa

retrospective study was performed at three Swedish hepatobiliary centers and included patients who underwent PVE 2013-2021. Electronic medical records were reviewed, and procedure-related data were collected. Data were analyzed with respect to embolizing material.

Results

A total of 265 patients were included: 160 in the NBCA group and 105 in the microparticle group. The NBCA group had a higher degree of hypertrophy (12.1 vs. 9.4 % points, p = 0.003) and a higher resection rate (68 vs. 59 %, p = 0.01) than the microparticle group. Procedure-related data all indicated the superiority of NBCA. No difference in inducing hypertrophy was observed when comparing patients who received chemotherapy before PVE with those who received chemotherapy before and after PVE within the NBCA group.

Discussion/conclusion

This retrospective multicenter study supports the superiority of NBCA compared to microparticles in the setting of PVE. Chemotherapy after PVE does not seem to negatively affect hypertrophy.

Imaging-guided interventions modulating portal venous flow: evidence and controversies

Portal hypertension is defined by an increase in the portosystemic venous gradient. In most cases, increased resistance to portal blood flow is the initial cause of elevated portal pressure. More than 90% of cases of portal hypertension are estimated to be due to advanced chronic liver disease or cirrhosis. Transjugular intrahepatic portosystemic shunts, a non-pharmacological treatment for portal hypertension, involve the placement of a stent between the portal vein and the hepatic vein or inferior vena cava which helps bypass hepatic resistance. Portal hypertension may also be a result of extrahepatic portal vein thrombosis or compression. In these cases, percutaneous portal vein recanalisation restores portal trunk patency, thus preventing portal hypertension-related complications. Any portal blood flow impairment leads to progressive parenchymal atrophy and triggers hepatic regeneration in preserved areas. This provides the rationale for using portal vein embolisation to modulate hepatic volume in preparation for extended hepatic resection. The aim of this paper is to provide a comprehensive evidence-based review of the rationale for, and outcomes associated with, the main imaging-guided interventions targeting the portal vein, as well as to discuss the main controversies around such approaches.

Portal Vein Embolization Using N-Butyl Cyanoacrylate-Glue: What Impact Does a Central Vascular Plug Have?

Purpose

To examine if the addition of a central vascular plug (CVP) to portal vein embolization (PVE) with N-butyl cyanoacrylate-glue (NBCA) increases future liver remnant (FLR) growth.

Material and Methods

This is a single-center retrospective study of 115 consecutive patients with colorectal liver metastases undergoing PVE in 2013–2019. All patients were embolized with NBCA as the main embolic agent. In 2017–2019 NBCA was combined with a CVP in the central part of the right portal vein. Growth of the FLR and standardized FLR (sFLR) including degree of hypertrophy (DH) and kinetic growth rate (KGR) were analyzed, as well as procedure data such as use of cone-beam CT (CBCT), dose area product (DAP), fluoroscopy time and contrast dose.

Results

A total of 40 patients (35%) underwent PVE with a combination of CVP and NBCA. The DH was higher in these patients after 4 weeks, mean 13.6% (SD 7.8) vs. 10.5% (SD 6.4; p = 0.022), verified in multivariate analysis (coefficient 4.1, p = 0.015). A CVP did not significantly increase the resection rate (90% vs 82%, p = 0.4). Cone beam CT was used in 65 patients (57%). Use of CBCT did not affect FLR growth, and fluoroscopy time and contrast doses were not different in patients having a CBCT or not. Slightly lower DAP (median 3375 vs. 4499 cGy*cm²; p = 0.09) was seen in procedures where CBCT was used.

Conclusion

A CVP in addition to NBCA embolization was associated with increased growth of the FLR compared to NBCA alone.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00270-021-03014-w.

Errors and Misinterpretations in Imaging of Chronic Liver Diseases

MRI is an important problem-solving tool for accurate characterization of liver lesions. Chronic liver disease alters the typical imaging characteristics and complicates liver imaging. Awareness of imaging pitfalls and technical artifacts and ways to mitigate them allows for more accurate and timely diagnosis.

Safety and outcomes of pre-operative portal vein embolization using N-butyl cyanoacrylate (Glue) in hepatobiliary malignancies: A single center retrospective analysis

Aims and Objectives:

To evaluate the outcome of preoperative portal vein embolization (PVE) using N-butyl cyanoacrylate (NBCA) for change in future liver remnant (FLR) volume, biochemical changes, and procedure-related complications. The factors affecting FLR hypertrophy and the rate of resection was also evaluated for this cohort.

Materials and Methods:

From 2012 to 2017, PVE utilizing NBCA mixed with lipiodol (1:4) was performed using percutaneous approach in 28 patients with hepatobiliary malignancies with low FLR. All patients underwent volumetric computed tomography (CT) assessment before and at 3–5 weeks after PVE and total liver volume (TLV), FLR volume, and FLR/TLV ratio, changes in portal vein diameter and factors affecting FLR were evaluated. Complications and the resectability rate were recorded and analyzed.

Result:

PVE was successful in all 28 patients. The mean FLR increased by 52% ± 32% after PVE (P < 0.0001). The FLR/TLV ratio was increased by 14.2% ± 2.8% (P < 0.001). Two major complications were encountered without any impact on surgery. There was no significant change seen in liver function test and complete blood counts after PVE. Eighteen patients (64.28%) underwent hepatic resection without any liver failure, and only three patients developed major complication after surgery. Remaining ten patients did not undergo surgery because of extrahepatic metastasis detected either on follow-up imaging or staging laparotomy. Patients with diabetes showed a lower rate of hypertrophy (P < 0.05).

Conclusion:

Preoperative PVE with NBCA is safe and effective for increasing FLR volume in patients of all age group and even in patients with an underlying liver parenchymal disease with hepatobiliary malignancy. Lesser hypertrophy was noted in patients with diabetes. A reasonable resectability was achieved despite having a high rejection in gall bladder cancer subgroup due to rapid disease progression.

Predictive Factors for Hypertrophy of the Future Liver Remnant After Portal Vein Embolization: A Systematic Review

This systematic review was conducted to determine factors that are associated with the degree of hypertrophy of the future liver remnant following portal vein embolization. An extensive search on September 15, 2020, and subsequent literature screening resulted in the inclusion of forty-eight articles with 3368 patients in qualitative analysis, of which 18 studies were included in quantitative synthesis. Meta-analyses based on a limited number of studies showed an increase in hypertrophy response when additional embolization of segment 4 was performed (pooled difference of medians = − 3.47, 95% CI − 5.51 to − 1.43) and the use of N-butyl cyanoacrylate for portal vein embolization induced more hypertrophy than polyvinyl alcohol (pooled standardized mean difference (SMD) = 0.60, 95% CI 0.30 to 0.91). There was no indication of a difference in degree of hypertrophy between patients who received neo-adjuvant chemotherapy and those who did not receive pre-procedural systemic therapy

(pooled SMD = − 0.37, 95% CI − 1.35 to 0.61), or between male and female patients (pooled SMD = 0.19, 95% CI − 0.12 to 0.50).

The study was registered in the International Prospective Register of Systematic Reviews on April 28, 2020 (CRD42020175708).

BestFLR Trial: Liver Regeneration at CT before Major Hepatectomies for Liver Cancer-A Randomized Controlled Trial Comparing Portal Vein Embolization with N-Butyl-Cyanoacrylate Plus Iodized Oil versus Polyvinyl Alcohol Particles Plus Coils

Background In patients with liver cancer, portal vein embolization (PVE) is recommended to promote liver growth before major hepatectomies. However, the optimal embolization strategy has not been established. Purpose To compare liver regeneration as seen at CT in participants with liver cancer, before major hepatectomies, with N-butyl-cyanoacrylate (NBCA) plus iodized oil versus standard polyvinyl alcohol (PVA) particles plus coils, for PVE. Materials and Methods In this single-center, prospective, randomized controlled trial (Best Future Liver Remnant, or BestFLR, trial; International Standard Randomized Controlled Trial Number 16062796), PVE with NBCA plus iodized oil was compared with standard PVE with PVA particles plus coils in participants with liver cancer. Participant recruitment started in November 2017 and ended in March 2020. Participants were randomly assigned to undergo PVE with PVA particles plus coils or PVE with NBCA plus iodized oil. The primary end point was liver growth assessed with CT 14 days and 28 days after PVE. Secondary outcomes included posthepatectomy liver failure, surgical complications, and length of intensive care treatment and hospital stay. The Mann-Whitney U test was used to compare continuous outcomes according to PVE material, whereas the Χ² test or Fisher exact test was used for categoric variables. Results Sixty participants (mean age, 61 years ± 11 [standard deviation]; 32 men) were assigned to the PVA particles plus coils group (n = 30) or to the NBCA plus iodized oil group (n = 30). Interim analysis revealed faster and superior liver hypertrophy for the NBCA plus iodized oil group versus the PVA particles plus coils group 14 days and 28 days after PVE (absolute hypertrophy of 46% vs 30% [P < .001] and 57% vs 37% [P < .001], respectively). Liver growth for the proposed hepatectomy was achieved in 87% of participants (26 of 30) in the NBCA plus iodized oil group versus 53% of participants (16 of 30) in the PVA particles plus coils group (P = .008) 14 days after PVE. Liver failure occurred in 13% of participants (three of 24) in the NBCA plus iodized oil group and in 27% of participants (six of 22) in the PVA particles plus coils group (P = .27). Conclusion Portal vein embolization with N-butyl-cyanoacrylate plus iodized oil produced greater and faster liver growth as seen at CT in participants with liver cancer, compared with portal vein embolization with polyvinyl alcohol particles plus coils, allowing for earlier surgical intervention. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Arellano in this issue.

Portal vein embolization with ethylene-vinyl alcohol copolymer for contralateral lobe hypertrophy before liver resection: safety, feasibility and initial experience

Background

To report our preliminary experience with preoperative portal vein embolization (PVE) using liquid ethylene vinyl alcohol (EVOH) copolymer.

Methods

Retrospectively review of patients with primary or secondary liver malignancies scheduled for extensive hepatectomy after the induction of future liver remnant (FLR) hypertrophy by right or left PVE with EVOH as the only embolic agent between 2014 and 2018 at two academic centers. Cross-sectional imaging liver volumetry data obtained before and 3-6 weeks after PVE were used to assess the FLR volume (FLRV) increase, degree of FLR hypertrophy and the FLR kinetic growth rate (KGR).

Results

Twenty-six patients (17 males; mean age, 58.7±11 years; range, 32-79 years) were included. The technical and clinical success rate was 100%. PVE produced adequate FLR hypertrophy in all patients. Embolization occurred in all targeted portal branches and in no non-target vessels. The %FLRV increased by 52.9%±32.5% and the degree of FLR hypertrophy was 16.7%±6.8%. The KGR was 4.4%±2.0% per week. Four patients experience minor complications after PVE which resolved with symptomatic treatment. The resection rate was 84.5%. One patient died during surgery for reasons unrelated to PVE.

Conclusions

Preoperative PVE with EVOH copolymer is feasible, safe, and effective in inducing FLR hypertrophy.

Portal vein embolization with N-butyl cyanoacrylate glue is superior to other materials: a systematic review and meta-analysis

OBJECTIVES

It remains uncertain which embolization material is best for portal vein embolization (PVE). We investigated the various materials for effectiveness in inducing future liver remnant (FLR) hypertrophy, technical and growth success rates, and complication and resection rates.

METHODS

A systematic review from 1998 to 2019 on embolization materials for PVE was performed on Pubmed, Embase, and Cochrane. FLR growth between the two most commonly used materials was compared in a random effects meta-analysis. In a separate analysis using local data (n = 52), n-butyl cyanoacrylate (NBCA) was compared with microparticles regarding costs, radiation dose, and procedure time.

RESULTS

In total, 2896 patients, 61.0 ± 4.0 years of age and 65% male, from 51 papers were included in the analysis. In 61% of the patients, either NBCA or microparticles were used for embolization. The remaining were treated with ethanol, gelfoam, or sclerosing agents. The FLR growth with NBCA was 49.1% ± 29.7 compared to 42.2% ± 40 with microparticles (p = 0.037). The growth success rate with NBCA vs microparticles was 95.3% vs 90.7% respectively (p < 0.001). There were no differences in major complications between NBCA and microparticles. In the local analysis, NBCA (n = 41) entailed shorter procedure time and reduced fluoroscopy time (p < 0.001), lower radiation exposure (p < 0.01), and lower material costs (p < 0.0001) than microparticles (n = 11).

CONCLUSION

PVE with NBCA seems to be the best choice when combining growth of the FLR, procedure time, radiation exposure, and costs.

KEY POINTS

• The meta-analysis shows that n-butyl cyanoacrylate (NBCA) is superior to microparticles regarding hypertrophy of the future liver remnant, 49.1% ± 29.7 vs 42.2% ± 40.0 (p = 0.037). • There is no significant difference in major complication rates for portal vein embolization using NBCA, 4% (24/681), compared with microparticles, 5% (25/494) (p > 0.05). • Local data shows a shorter procedure time, 215 vs 348 mins from arrival to departure at the interventional radiology unit, and fluoroscopy time, 43 vs 96 mins (p < 0.001), lower radiation dosage, 573 vs 1287 Gycm² (p < 0.01), and costs, €816 vs €4233 (p < 0.0001) for NBCA compared to microparticles.

Radiological Simultaneous Portohepatic Vein Embolization (RASPE) Before Major Hepatectomy: A Better Way to Optimize Liver Hypertrophy Compared to Portal Vein Embolization

OBJECTIVE

The aim of this retrospective study was to compare portal vein embolization (PVE) and radiologica simultaneous portohepatic vein embolization (RASPE) for future liver remnant (FLR) growth in terms of feasibility, safety, and efficacy.

SUMMARY OF BACKGROUND DATA

After portal vein embolization (PVE), 15% of patients remain ineligible for hepatic resection due to insufficient hypertrophy of the FLR. RASPE has been proposed to induce FLR growth.

MATERIALS AND METHODS

Between 2016 and 2018, 73 patients were included in the study. RASPE was proposed for patients with a ratio of FLR to total liver volume (FLR/TLV) of <25% (RASPE group). This group was compared to patients who underwent PVE for a FLR/TLV <30% (PVE group). Patients in the 2 groups were matched for age, sex, type of tumor, and number of chemotherapy treatments. FLR was assessed by computed tomography before and 4 weeks after the procedure.

RESULTS

The technical success rate in both groups was 100%. Morbidity post-embolization, and the time between embolization and surgery were similar between the groups. In the PVE group, the FLR/TLV ratio before embolization was 31.03% (range: 18.33%-38.95%) versus 22.91% (range: 16.55-32.15) in the RASPE group (P < 0.0001). Four weeks after the procedure, the liver volume increased by 28.98% (range: 9.31%-61.23%) in the PVE group and by 61.18% (range: 23.18%-201.56%) in the RASPE group (P < 0.0001). Seven patients in the PVE group, but none in the RASPE group, had postoperative liver failure (P = 0.012).

CONCLUSIONS

RASPE can be considered as "radiological associating liver partition and portal vein ligation for staged hepatectomy." RASPE induced safe and profound growth of the FLR and was more efficient than PVE. RASPE also allowed for extended hepatectomy with less risk of post-operative liver failure.

Preparing for liver surgery with "Alphabet Soup": PVE, ALPPS, TAE-PVE, LVD and RL

Future liver remnant (FLR) size and function is a critical limiting factor for treatment eligibility and postoperative prognosis when considering surgical hepatectomy. Pre-operative portal vein embolization (PVE) has been proven effective in modulating FLR and now widely accepted as a standard of care. However, PVE is not always effective due to potentially inadequate augmentation of the FLR as well as tumor progression while awaiting liver growth. These concerns have prompted exploration of alternative techniques: associating liver partition and portal vein ligation for staged hepatectomy (ALPPS), transarterial embolization-portal vein embolization (TAE-PVE), liver venous deprivation (LVD), and radiation lobectomy (RL). The article aims to review the principles and applications of PVE and these newer hepatic regenerative techniques.

Preoperative Portal Vein Embolization in Hepatic Surgery: A Review about the Embolic Materials and Their Effects on Liver Regeneration and Outcome

Liver volume and function after hepatectomies are directly correlated to postoperative complications and mortality. Consequently contemporary liver surgery has focused on reaching an adequate future liver remnant so as to diminish postoperative morbidity and mortality. Portal vein embolization has evolved and is the standard of care as a liver regenerative strategy in many surgery departments worldwide before major liver resections. Different embolic materials have been used for portal vein embolization including gelfoam, ethanol, polyvinyl-alcohol particles, calibrated microspheres, central vascular plugs, coils, n-butyl-cyanoacrylate glue, fibrin glue, polidocanol-foam, alcoholic prolamin solution, and ethylene vinyl alcohol copolymer, as sole occluders or in varied combinations. While to date there has been no prospective controlled trial comparing the efficacy of different embolic materials in portal vein embolization, retrospective data insinuates that the use of n-butyl-cyanoacrylate and absolute ethanol produces higher contralateral liver hypertrophies. In this review, we evaluated publications up to August 2019 to assess the technical and regenerative results of portal vein embolization accomplished with different embolic materials. Special attention was given to specific aspects, advantages, and drawbacks of each embolic agent used for portal vein embolization, its liver regenerative performance, and its influence on patient outcome.

Segment 4 occlusion in portal vein embolization increase future liver remnant hypertrophy - A Scandinavian cohort study

BACKGROUND

The additional value of including segment 4 (S4) portal branches in right portal vein embolization (rPVE) is debated. The aim of the study was to explore this in a large multicenter cohort.

MATERIAL AND METHODS

A retrospective cohort study consisting of all patients subjected to rPVE from August 2012 to May 2017 at six Scandinavian university hospitals. PVE technique was essentially the same in all centers, except for the selection of main embolizing agent (particles or glue). All centers used coils or particles to embolize S4 branches. A subgroup analysis was performed after excluding patients with parts of or whole S4 included in the future liver remnant (FLR).

RESULTS

232 patients were included in the study, of which 36 received embolization of the portal branches to S4 in addition to rPVE. The two groups (rPVE vs rPVE + S4) were similar (gender, age, co-morbidity, diagnosis, neoadjuvant chemotherapy, bilirubin levels prior to PVE and embolizing material), except for diabetes mellitus which was more frequent in the rPVE + S4 group (p = 0.02). Pre-PVE FLR was smaller in the S4 group (333 vs 380 ml, p = 0.01). rPVE + S4 resulted in a greater percentage increase of the FLR size compared to rPVE alone (47 vs 38%, p = 0.02). A subgroup analysis, excluding all patients with S4 included in the FLR, was done. There was no longer a difference in pre-PVE FLR between groups (333 vs 325 ml, p = 0.9), but still a greater percentage increase and also absolute increase of the FLR in the rPVE + S4 group (48 vs 38% and 155 vs 112 ml, p = 0.01 and 0.02).

CONCLUSION

In this large multicenter cohort study, additional embolization of S4 did demonstrate superior growth of the FLR compared to standard right PVE.

[Interventional radiology of liver tumors]

Interventional radiology (IR) has considerably grown since the 90s and has currently a central position in the management of patients suffering from cancer. The aim of this paper is to describe the principle, indications, technique and results of three common hepatic oncologic IR procedures: preoperative portal vein embolization, transarterial chemoembolization and radioembolization. Portal vein embolization is performed before a right hepatectomy in order to increase the left liver volume and functional capacity to ensure adequate liver function of the future remnant liver and to prevent the post-hepatectomy liver failure. It is a proven, well-tolerated and effective technique, allowing most of patients to undergo surgery. Transarterial chemoembolization consists of an injection of a chemotherapeutic agent and an embolic agent into the hepatic artery to locally act on liver tumors. It is the standard of care for BCLC stage B hepatocellular carcinoma and is also recommended for the liver metastases treatment, mainly from neuroendocrine tumors. Radioembolization is an IR procedure on the rise that consists of the injection into the hepatic artery of Yttrium 90 loaded microparticles, which will preferentially deliver high dose on the tumors, sparing the adjacent hepatic parenchyma. Radioembolization is recommended for the palliative treatment of HCC and for colorectal cancer liver metastases resistant to treatment. It is a very well tolerated intervention which place has yet to be defined in the management of neuroendocrine tumors liver metastases and unresectable cholangiocarcinoma. IR is a constantly evolving discipline with proven techniques playing a major role in the oncological management of liver tumor patients. In oncology, IR is now the 4th patient management linchpin alongside oncology, surgery and radiotherapy.

Portal Vein Embolization with PVA and Coils before Major Hepatectomy: Single-Center Retrospective Analysis in Sixty-Four Patients

Objectives

Portal vein embolization (PVE) stimulates hypertrophy of the future liver remnant (FLR) and improves the safety of extended hepatectomy. This study evaluated the efficacy of PVE, performed with PVA and coils, in relation to its effect on FLR volume and ratio. Secondary endpoints were the assessment of PVE complications, accomplishment of liver surgery, and patient outcome after hepatectomy.

Materials and Methods

All patients who underwent PVE before planned major hepatectomy between 2013 and 2017 were retrospectively analyzed, comprising a total of 64 patients. Baseline patient clinical characteristics, imaging records, liver volumetric changes, complications, and outcomes were analyzed.

Results

There were 45 men and 19 women with a mean age of 64 years. Colorectal liver metastasis was the most frequent liver tumor. The majority of patients (n = 53) had a right PVE. FLR increased from a mean value of 484 ml ± 242 to 654 ml ± 287 (p < 0.001) after PVE. Two major complications were experienced after PVE: 1 case of left hepatic artery branch laceration and 1 case of hemoperitoneum and hemothorax. A total of 44 (69%) patients underwent liver surgery. Twenty-one patients were not taken to surgery due to disease progression (n = 18), liver insufficiency (n = 1), and insufficient FLR volume (n = 1), and one patient declined surgery (n = 1).

Conclusions

PVE with PVA and coils was accomplished safely and promoted a high FLR hypertrophy yield, enabling most of our patients to be submitted to the potentially curative treatment of liver tumor resection.

Future liver remnant growth after various portal vein embolization regimens: a quantitative comparison

Purpose: To compare the efficacy of right portal vein embolization using ethylene vinyl alcohol (EVOH-PVE) compared to other embolic agents and surgical right portal vein ligation (PVL).Material and methods: Patients with right sided liver malignancies scheduled for extensive surgery and receiving induction of liver hypertrophy via right portal vein embolization/ligature between 2010-2016 were retrospectively evaluated. Treatments included were ethylene vinyl alcohol copolymer (Onyx®, EVOH-PVE), ethiodized oil (Lipiodol^®, Lipiodol/PVA-PVE), polyvinyl alcohol (PVA-PVE) or surgical ligature (PVL). Liver segments S2/3 were used to assess hypertrophy. Primary outcome was future liver remnant growth in ml/day.Results: Forty-one patients were included (EVOH-PVE n = 11; Lipiodol/PVA-PVE n = 10; PVA-PVE n = 8; PVL n = 12), the majority presenting with cholangiocarcinoma and colorectal metastases (n = 11; n = 27). Pre-interventional liver volumes were comparable (p = .095). Liver hypertrophy was successfully induced in all but one patient receiving Lipiodol/PVA-PVE. Liver segment S2/3 growth was largest for EVOH-PVE (5.38 ml/d) followed by PVA-PVE (2.5 ml/d), with significantly higher growth rates than PVL (1.24 ml/d; p < .001; p = .007). No significant difference was evident for Lipiodol/PVA-PVE (1.43 ml/d, p = .809).Conclusions: Portal vein embolization using EVOH demonstrates fastest S2/3 growth rates compared to other embolic agents and PVL, potentially due to its permanent portal vein embolization and induction of hepatic inflammation.

Intrahepatic portal-venous shunts during PVE

Portal venous embolization (PVE) is a well-validated technique to promote contralateral liver lobe hypertrophy prior to hepatic resection. We present a case of a patient with Type IV cholangiocarcinoma undergoing PVE prior to hepatic surgical resection. However, intrahepatic portal-venous shunts were incidentally found during the procedure and were subsequently embolized using embolic coils and N-butyl cyanoacrylate. While most patients with congenital portal-venous shunts remain asymptomatic, an unrecognized shunt during PVE could have resulted in a devastating complication secondary to nontarget embolization through the fistula. To our knowledge, this is the first reported case of a portal-venous shunt being discovered during a PVE.

The technical aspects of a feasible new technique for ipsilateral percutaneous transhepatic portal vein embolization

OBJECTIVE:

To devise a simple new technique wherein absolute ethanol is injected via a sheath under proximal balloon occlusion of the right portal vein using a single-balloon catheter and to examine its feasibility and safety for ipsilateral portal vein embolization (PVE).

METHODS:

Between 2010 and 2016, PVE was performed in 19 patients prior to undergoing extended right hepatectomy. PVE was performed via a percutaneous transhepatic ipsilateral approach, the right portal branch was embolized under ultrasound guidance, and a balloon catheter was placed in the proximal site of the main right portal branch. Absolute ethanol was injected through a sheath under proximal balloon occlusion of the right portal vein using a double-lumen catheter. We evaluated its technical success and complications following PVE and changes in liver enzyme levels. Furthermore, we calculated changes in future liver remnant (FLR) and FLR/total functional liver volume (TFLV) ratio and assessed complications following hepatic resection.

RESULTS:

PVE was successfully performed in all patients. Mean FLR and FLR/TFLV significantly increased following PVE (p < 0.01). The change in the FLR and FLR/TFLV ratio was 39.6 ± 16.2%. One patient (6.5%) developed procedure-related complications following PVE (perihepatic hematoma).

CONCLUSION:

The new technique for ipsilateral right PVE is safe, effective, and convenient.

ADVANCES IN KNOWLEDGE:

This is the first study to investigate the efficacy of injecting ethanol via a sheath under proximal balloon occlusion of the right portal vein using a single-balloon catheter.

Portal Vein Embolization: Correlation of Future Liver Remnant Hypertrophy to Type of Embolic Agent Used

Purpose

The purpose of this study was to compare the effectiveness of portal vein embolization (PVE) with different embolic agents used at our centre. Specifically, the effectiveness of N-butyl cyanoacrylate (NBCA) glue is compared with that of polyvinyl alcohol (PVA) particles.

Methods

We performed a retrospective chart review of all patients (N = 77) who underwent PVE at our institution over a 5-year period. Pre- and postprocedural computed tomography or magnetic resonance imaging, when available, were used to measure the volume of total liver volume and future liver remnant (FLR). The absolute values obtained were used to calculate percentage of FLR. The growth in FLR was determined 4–6 weeks after PVE. Technical details of the procedure including the type and amount of embolic agent used were obtained from the chart reviews, electronic patient records, and radiology reports. Statistical analysis was performed using Kruskal-Wallis test, Wilcoxon rank sum test, and the Spearman correlation coefficient with post hoc analysis. Results are expressed as mean ± SD ( P < .05 considered statistically significant).

Results

NBCA (n = 29) produced a mean change in FLR of 14.8% compared with 9.3% for PVA particles (n = 24; P = .007). Mean change in FLR was 10.1% in the group where a combination of NBCA and PVA particles was used (n = 24). The effect of glue volume and glue-to-lipiodol ratio on the outcome was not found to be statistically significant ( P = .5 and .7, respectively).

Conclusions

We conclude that NBCA glue is a better embolic agent than PVA particles in inducing liver hypertrophy.

Ethylene vinyl alcohol copolymer for occlusion of specific portal branches during preoperative portal vein embolisation with n-butyl-cyanoacrylate

OBJECTIVES

To evaluate the safety and efficacy of ethylene vinyl alcohol copolymer (EVOH) injection for selective occlusion of portal branches considered at risk for non-target embolisation during preoperative portal vein embolisation (PVE).

METHODS

Twenty-nine patients (mean age, 57 ± 17 years) submitted to PVE with n-butyl-cyanoacrylate (NBCA) and additional EVOH for selected portal branches were retrospectively analysed. Indications for the use of EVOH and the selected portal branches were evaluated. Degree of hypertrophy of the future liver remnant (FLR) and kinetic growth were assessed by CT volumetry performed before and 3-6 weeks after PVE. Clinical outcome and histopathological analysis of portal veins occluded with EVOH were reviewed.

RESULTS

EVOH was indicated intraoperatively for embolisation of selected portal branches that the operator reported at risk to provoke non-target embolisation with NBCA. Indications for the use of EVOH were embolisation of segment IV (n = 21), embolisation of segmental portal branches with early bifurcation (n = 7) and PVE in a 1-year-old girl with cystic hamartomas. All targeted portal branches were successfully embolised. There were no cases with non-target embolisation by EVOH. The degree of hypertrophy of the FLR was 14.3 ± 8.1% and the kinetic growth rate was 2.7 ± 1.8% per week.

CONCLUSION

EVOH is safe and effective for embolisation of selected portal vein branches considered at risk for non-target embolisation.

KEY POINTS

• EVOH is another effective liquid embolic agent for preoperative PVE. • EVOH is relatively simple to handle with a minimal risk of non-target embolisation. • During PVE, some portal branches considered complicated to occlude with NBCA may be efficiently embolised with EVOH.

Portal Vein Embolization Utilizing N-Butyl Cyanoacrylate for Contralateral Lobe Hypertrophy Prior to Liver Resection: A Systematic Review and Meta-Analysis

PURPOSE

To evaluate the safety and effectiveness of n-butyl cyanoacrylate (NBCA) for portal vein embolization (PVE) when used to induce contralateral future liver remnant (FLR) hypertrophy in patients undergoing planned hepatic resection for hepatic malignancy.

MATERIALS AND METHODS

The PubMed database (including articles indexed by MEDLINE) was searched for articles published from 1970 to 2018 describing patients treated with PVE utilizing NBCA to induce hypertrophy of the FLR prior to contralateral hepatic lobe resection. Demographic data, embolization technique, complications of embolization, resultant FLR hypertrophy, and surgical outcomes were obtained when available. A meta-analysis was performed to determine the cumulative relative hypertrophy rate of the FLR following PVE with NBCA.

RESULTS

The literature search yielded 18 relevant articles. Six hundred and seven patients (383 men, 220 women; mean age 60.7 years) with procedures describing PVE utilizing NBCA were reviewed. The most common underlying hepatic malignancies were colorectal metastases (n = 348), followed by cholangiocarcinomas (n = 92), and hepatocellular carcinomas (n = 89). Technical success was reportedly achieved in 603/607 patients, for a success rate of 99.3%. Fixed effects meta-analysis of the relative hypertrophy rate of the FLR among studies resulted in an aggregate rate of 49.4 ± 1.3%. Of the patients who underwent attempted PVE, 461/607 (75.9%) eventually underwent surgical resection. Major complications following PVE occurred in 19 patients (3.13%), while minor complications following PVE occurred in 38 patients (6.26%).

CONCLUSIONS

PVE utilizing NBCA to induce hypertrophy of the FLR prior to contralateral lobe resection in the setting of hepatic malignancy is safe and effective.

LEVEL OF EVIDENCE

Level IIa-Systematic review of cohort studies.

Efficacy of percutaneous transhepatic portal vein embolization using gelatin sponge particles and metal coils

Background

Percutaneous transhepatic portal vein embolization (PTPE) can increase the future liver remnant (FLR) volume before extended liver resection; however, there is no current consensus regarding the best embolic material for PTPE.

Purpose

To evaluate the efficacy of PTPE using gelatin sponge particles and coils.

Material and Methods

The medical records of 136 patients who underwent PTPE using gelatin sponge particles and metal coils were retrospectively reviewed. We evaluated the procedural details, liver volume on CT, and clinical status before and after PTPE.

Results

The mean FLR volume increased significantly from 390 ± 147 cm³ to 508 ± 141 cm³ (P < 0.001). A mean of 22.1 ± 9.4 days after PTPE, the mean increase in the ratio of FLR volume to total liver volume was 9.4 ± 6.5%. Complications related to PTPE occurred in five patients, including arterial damage (n = 4) and biloma (n = 1). The white blood cell count and C-reactive protein level increased significantly and then returned to baseline within seven days. Aspartate aminotransferase and alanine aminotransferase showed no significant changes. Fever (defined by the Common Terminology Criteria for Adverse Events v4.0) was reported in 74 patients (54%), but it was generally mild (Grade 1/2; n = 72). None of the patients experienced severe complications that required cancellation of surgery.

Conclusion

PTPE with gelatin sponge particles and coils may impose low physical stress on patients and is a safe method of inducing a significant increase of FLR.

Portal vein embolization with n-butyl-cyanoacrylate through an ipsilateral approach before major hepatectomy: single center analysis of 50 consecutive patients

Purpose

To evaluate the efficacy of portal vein embolization (PVE) with n-Butyl-cyanoacrylate (NBCA) through an ipsilateral approach before major hepatectomy. Secondary end-points were PVE safety, liver resection and patient outcome.

Methods

Over a 5-year period 50 non-cirrhotic consecutive patients were included with primary or secondary liver cancer treatable by hepatectomy with a liver remnant (FLR) volume less than 25% or less than 40% in diseased livers.

Results

There were 37 men and 13 women with a mean age of 57 years. Colorectal liver metastases were the most frequent tumor and patients were previously exposed to chemotherapy. FLR increased from 422 ml to 629 ml (P < 0.001) after PVE, corresponding to anincrease of 52%. The FLR ratio increased from 29.6% to 42.3% (P < 0.001). Kinetic growth rate was 2.98%/week. A negative association was observed between increase in the FLR and FLR ratio and FLR volume before PVE (P = 0.002). In 31 patients hepatectomy was accomplished and only one patient presented with liver insufficiency within 30 days after surgery.

Conclusions

PVE with NBCA through an ipsilateral puncture is effective before major hepatectomy. Meticulous attention is needed especially near the end of the embolization procedure to avoid complications.

Trial registration

Clinical Study ISRCTN registration number: ISRCTN39855523. Registered March 13th 2017.

[Portal vein embolization: Present and future]

Portal vein embolization consists of occluding a part of the portal venous system in order to achieve the hypertrophy of the non-embolized liver segments. This technique is used during the preoperative period of major liver resection when the future remnant liver (FRL) volume is insufficient, exposing to postoperative liver failure, main cause of death after major hepatectomy. Portal vein embolization indication depends on the FRL, commonly assessed by its volume. Nowadays, FRL function evaluation seems more relevant and can be measured by 99mTc labelled mebrofenin scintigraphy. Portal vein embolization procedure is mostly performed with percutaneous trans-hepatic access by using ultrasonography guidance and consists of embolic agent injection, such as cyanoacrylate, in the targeted portal vein branches with fluoroscopic guidance. It is a safe and well-tolerated technique, with extremely low morbi-mortality. Portal vein embolization leads to sufficient FRL hypertrophy in about 80% of patients, allowing them to undergo surgery from which they were initially rejected. The two main reasons of non-resection are tumor progression (≈15% of cases) and FRL insufficient hypertrophy (≈5% of cases). When portal vein embolization is not enough to obtain adequate FRL regeneration, hepatic vein embolization may potentiate its effect (liver venous deprivation technique).

Current status and future perspectives on treatment of liver metastasis in colorectal cancer (Review)

Liver metastasis is the most common site of colorectal cancer (CRC) metastasis. Approximately half of all colorectal cancer patients will develop liver metastases. Although radical surgery is the standard treatment modality, only 10-20% of patients are deemed eligible for resection. Despite advances in survival with chemotherapy, surgical resection is still considered the only curative option for patients with liver metastases. Much effort has been expended to address patients with metastatic liver disease. The majority of evidence stated a significant survival benefit with surgical resection to reach an overall 5-year survival rate of 35-55% after hepatic resection. However, still majority of patients will experience disease recurrence even after a successful resection. In this review, we describe current status and controversies related to treatment options for CRC liver metastases and its potential for enhancing oncologic outcomes and improving quality of life.

Identification of cofactors influencing hypertrophy of the future liver remnant after portal vein embolization-the effect of collaterals on embolized liver volume

OBJECTIVE

The purpose of this retrospective study was to monitor hypertrophy of future liver remnant following portal vein embolization (PVE) before planned extended right hepatectomy. However, because individual responses to PVE are highly variable, our focus was to identify cofactors of successful hypertrophy.

METHODS

28 patients with primary or secondary liver tumours, mean age 64.1 ± 12.9 years, underwent PVE. Volumetric analysis of hypertrophy before and after PVE (median 39.0 ± 15.7 days) was performed. The embolized liver segments were investigated for occurrence of reperfusion of their portal branches. Blood parameters before PVE were additionally investigated.

RESULTS

Patients were divided into responders (21/28) and non-responders (7/28) by post-PVE standardized future liver remnant being above or below 25%, respectively. No significant differences between the groups were found regarding biometric and volumetric parameters before PVE. In the entire group after PVE, the mean absolute increase of Segments 2 and 3 was 196.0 ± 84.7 cm³ and the median relative increase was 46.6 ± 98.8%. The formation of left to right hepatic portoportal collaterals exhibited a negative correlation to successful hypertrophy (p = 0.004) as well as low plasma total protein (p = 0.019). Successful embolization of Segment IV showed only a trend to significance (p = 0.098).

CONCLUSION

Cofactors associated with a favourable outcome regarding hypertrophy were the absence of collaterals in the control CT scans and high plasma total protein. Advances in knowledge: Portoportal collaterals negatively influence hypertrophy after PVE. On the other hand, plasma total protein is a positive prognostic indicator on hypertrophy of the liver in our cohort.

Meta-analysis of associating liver partition with portal vein ligation and portal vein occlusion for two-stage hepatectomy

BACKGROUND

Discussion is ongoing regarding whether associating liver partition with portal vein ligation for staged hepatectomy (ALPPS) or portal vein occlusion is better in staged hepatectomy. The aim of this study was to compare available strategies using a two-stage approach in extended hepatectomy.

METHODS

A literature search was performed in MEDLINE, Scopus, the Cochrane Library and Embase, and additional articles were identified by hand searching. Data from the international ALPPS registry were extracted. Clinical studies reporting volumetric changes, mortality, morbidity, feasibility of the second stage and tumour-free resection margins (R0) in two-stage hepatectomy were included.

RESULTS

Ninety studies involving 4352 patients, including 320 from the ALPPS registry, met the inclusion criteria. Among these, nine studies (357 patients) reported on comparisons with other strategies. In the comparison of ALPPS versus portal vein embolization (PVE), ALPPS was associated with a greater increase in the future liver remnant (76 versus 37 per cent; P < 0·001) and more frequent completion of stage 2 (100 versus 77 per cent; P < 0·001). Compared with PVE, ALPPS had a trend towards higher morbidity (73 versus 59 per cent; P = 0·16) and mortality (14 versus 7 per cent; P = 0·19) after stage 2. In the non-comparative studies, complication rates were 39 per cent in the PVE group, 47 per cent in the portal vein ligation (PVL) group and 70 per cent in the ALPPS group. After stage 2, mortality rates were 5, 7 and 12 per cent respectively.

CONCLUSION

ALPPS is associated with greater future liver remnant hypertrophy and a higher rate of completion of stage 2, but this may be at the price of greater morbidity and mortality.

Comparison of Clinical Outcomes following Glue versus Polyvinyl Alcohol Portal Vein Embolization for Hypertrophy of the Future Liver Remnant prior to Right Hepatectomy

PURPOSE

To report outcomes after portal vein embolization (PVE) and right hepatectomy in patients receiving embolization with N-butyl cyanoacrylate (NBCA) glue + central AMPLATZER Vascular Plug (AVP; glue group) or polyvinyl alcohol (PVA) particles ± coils (PVA group).

MATERIALS AND METHODS

Between March 2008 and August 2013, all patients having PVE with NBCA + AVP or PVA ± coils before right hepatectomy were retrospectively reviewed; 85 patients underwent PVE with NBCA + AVP (n = 45) or PVA ± coils (n = 40). The groups were compared using Mann-Whitney U and χ² tests.

RESULTS

Technical success of embolization was 100%. Degree of hypertrophy (16.2% ± 7.8 vs 12.3% ± 7.62, P = .009) and kinetic growth rate (3.5%/wk ± 2.0 vs 2.6%/wk ± 1.9, P = .016) were greater in the glue group versus the PVA group. Contrast volume (66.1 mL ± 44.8 vs 189.87 mL ± 62.6, P < .001) and fluoroscopy time (11.2 min ± 7.8 vs 23.49 min ± 11.7, P < .001) were significantly less during the PVE procedure in the glue group. Surgical outcomes were comparable between groups, including the number of patients unable to go onto surgery (P = 1.0), surgical complications (P = .30), length of hospital stay (P = .68), and intensive care unit admissions (P = .71). There was 1 major complication (hepatic abscess) in each group after PVE.

CONCLUSIONS

PVE performed with NBCA + AVP compared with PVA ± coils resulted in greater degree of hypertrophy of the future liver remnant, less fluoroscopic time and contrast volume, and similar complication rates.

Controversies of preoperative portal vein embolization

Portal vein embolization (PVE) is a safe, percutaneous procedure that has been proven to lower the complication rates of curative intent large-volume hepatic resection by inducing hypertrophy of the future liver remnant. While the safety and efficacy of PVE has been well substantiated, there remains controversy with regards to the technical details, periprocedural management, and whether alternative methods of achieving future liver remnant hypertrophy are preferable to PVE. This paper will address those controversies and offer recommendations based on available data.

Portal vein embolization for induction of selective hepatic hypertrophy prior to major hepatectomy: rationale, techniques, outcomes and future directions

The ability to modulate the future liver remnant (FLR) is a key component of modern oncologic hepatobiliary surgery practice and has extended surgical candidacy for patients who may have been previously thought unable to survive liver resection. Multiple techniques have been developed to augment the FLR including portal vein embolization (PVE), associating liver partition and portal vein ligation (ALPPS), and the recently reported transhepatic liver venous deprivation (LVD). PVE is a well-established means to improve the safety of liver resection by redirecting blood flow to the FLR in an effort to selectively hypertrophy and ultimately improve functional reserve of the FLR. This article discusses the current practice of PVE with focus on summarizing the large number of published reports from which outcomes based practices have been developed. Both technical aspects of PVE including volumetry, approaches, and embolization agents; and clinical aspects of PVE including data supporting indications, and its role in conjunction with chemotherapy and transarterial embolization will be highlighted. PVE remains an important aspect of oncologic care; in large part due to the substantial foundation of information available demonstrating its clear clinical benefit for hepatic resection candidates with small anticipated FLRs.

A comparison of portal vein embolization with poly(2-hydroxyethylmethacrylate) and a histoacryl/lipiodol mixture in patients scheduled for extended right hepatectomy

To determine whether PHEMA [poly(2-hydroxyethylmethacrylate)] is suitable for portal vein embolization in patients scheduled to right hepatectomy and whether it is as effective as the currently used agent (a histoacryl/lipiodol mixture). Two groups of nine patients each scheduled for extended right hepatectomy for primary or secondary hepatic tumor, had right portal vein embolization in an effort to induce future liver remnant (FLR) hypertrophy. One group had embolization with PHEMA, the other one with the histoacryl/lipiodol mixture. In all patients, embolization was performed using the right retrograde transhepatic access. Embolization was technically successful in all 18 patients, with no complication related to the embolization agent. Eight patients of either group developed FLR hypertrophy allowing extended right hepatectomy. Likewise, one patient in each group had recanalization of a portal vein branch. Histology showed that both embolization agents reach the periphery of portal vein branches, with PHEMA penetrating somewhat deeper into the periphery. PHEMA has been shown to be an agent suitable for embolization in the portal venous system comparable with existing embolization agent (histoacryl/lipiodol mixture).

Tumour growth after portal vein embolization with pre-procedural chemotherapy for colorectal liver metastases

BACKGROUND

For resection of colorectal cancer (CRC) liver metastases, pre-operative portal vein embolization (PVE) is used to increase the size of the future liver remnant (FLR) prior to advanced liver resection when indicated. PVE is speculated to cause tumour progression, but only a limited number of studies have analysed tumour growth after PVE in the context of pre-procedural chemotherapy, which was the aim of this retrospective study.

METHODS

Patients treated with stabilizing chemotherapy and PVE before liver resection for CRC metastases were included. Tumour progression according to RECIST guidelines and a change in tumour volume was analysed on computed tomography (CT) scans prior to chemotherapy, before PVE and after PVE, respectively.

RESULTS

Thirty-four patients were included, of whom 23 had bilobar disease. Of tumours in the embolized lobe, 3/34 showed progression after PVE as compared with 3/23 in the non-embolized lobe (P = 0.677). A decrease in tumour volume of 16% and 11% was noted in the embolized and non-embolized lobe, respectively (P = 0.368). Patients were off chemotherapy in a median of 16 days before PVE. There was a linear correlation between the growth of tumours and time between the end of chemotherapy and PVE (r = 0.25, P = 0.0005).

CONCLUSION

The rate of progression of CRC liver metastases after PVE and pre-procedural chemotherapy was lower in the present study as compared with previous reports. This applies to tumours in both the embolized and non-embolized lobes and is associated with keeping the time between the end of chemotherapy and PVE short.

Right portal vein embolization with absolute ethanol in major hepatic resection for hepatobiliary malignancy

BACKGROUND

This study aimed to evaluate the safety and efficacy of preoperative right portal vein embolization (PVE) with absolute ethanol in patients with hepatobiliary malignancies.

METHODS

PVE was performed via a percutaneous transhepatic ipsilateral approach, and the right portal branch was embolized with absolute ethanol. Technical success and complications following PVE, and changes in liver enzyme levels were evaluated. Changes in future liver remnant (FLR) and FLR/total functional liver volume ratio were calculated. Complications following hepatic resection were assessed.

RESULTS

A total of 83 patients with hepatobiliary malignancies (53 men, 30 women; mean age 68 years) underwent right PVE. Tumour types were hilar cholangiocarcinoma (37), liver metastases (14), gallbladder cancer (13), intrahepatic cholangiocellular carcinoma (10) and hepatocellular carcinoma (HCC) (9). PVE was performed successfully in all patients. Four patients (5 per cent) developed complications following PVE (liver abscess 2, left portal vein thrombosis 1, pseudoaneurysm 1), but this did not preclude hepatic resection. Liver enzyme levels rose transiently after PVE. The mean FLR and FLR/total functional liver volume increased after PVE (from 366 to 513 cm(3) and from 31 to 43 per cent respectively; both P < 0·001). Changes in the FLR and FLR/total functional liver volume ratio were comparable between patients with HCC and those with other malignancies (42 and 44 per cent, and 12 and 12 per cent, respectively). Sixty-nine of 83 patients underwent hepatic resection at a median of 25 days after PVE, with no postoperative mortality.

CONCLUSION

Preoperative right PVE with absolute ethanol is safe and effective for induction of selective hepatic hypertrophy in patients with hepatobiliary malignancy.

A review of animal models for portal vein embolization

BACKGROUND

Portal vein embolization (PVE) is a preoperative intervention to increase the future remnant liver (FRL) through regeneration of the non-embolized liver lobes. This review assesses all the relevant animal models of PVE available, to guide researchers who intend to study PVE.

MATERIALS AND METHODS

We performed a systematic literature search in Medline and Pubmed, from 1993-June 2013, using search headings "PVE" and "portal vein ligation". Articles were included when meeting the selection criteria: experimental animal study on PVE or portal vein ligation and experiments described in 5 animals or more.

RESULTS

Sixty-one articles were selected, describing six different animal models. Most articles reported experiments with rats, rabbits, and pigs. In rats, the increase in wet-weight ratio of the non-occluded liver or total liver weight is greatest in the first 7 d with values ranging from 75%-80.5% on day 7. The volume increase of FRL in the rabbit model is greatest in the first 7 d with values ranging from 33.6%-80% on day 7. In pigs, the largest gain in volume of the FRL was seen in the first 2 wk.

CONCLUSIONS

The choice of the model depends on the specific aim of the study. Evaluating the increase in liver volume and liver function after PVE, larger animals as the pig, rabbit, or the dog is useful because of the possibility to apply computed tomography volumetry. To evaluate mechanisms of regeneration after PVE, the rat model is useful, because of the variety of antibodies commercially available.

Portal vein embolization before right hepatectomy or extended right hepatectomy using sodium tetradecyl sulfate foam: technique and initial results

PURPOSE

To evaluate the safety and efficacy of portal vein embolization (PVE) with sodium tetradecyl sulfate (STS) foam.

MATERIALS AND METHODS

A single-center retrospective review of 35 patients (27 men and 8 women; mean age, 61 y) who underwent PVE with STS foam was performed. The technical success rate, rate of PVE at producing adequate future liver remnant (FLR) hypertrophy, and rate of disease progression precluding resection after PVE were analyzed. Complications of PVE and liver resection after PVE were recorded.

RESULTS

PVE was performed on 35 patients before right hepatic resection for both primary and secondary hepatic malignancies (22 hepatocellular carcinoma, 10 metastasis, 2 cholangiocarcinoma, 1 invasive gallbladder carcinoma). Technical success was achieved in 97.1% (34 of 35) of patients. Mean FLR of the total estimated liver volume increased from 24.5% (SD, 7.7%) to 36.5% (SD, 14.5%), a mean percentage increase of 48.8% (SD, 34.3%). PVE produced adequate FLR hypertrophy in 31 of 35 patients (88.6%). Proposed right hepatectomy was subsequently performed in 27 patients (77.1%). One patient remains scheduled for surgery, two had peritoneal spread at surgery and resection was aborted, two had disease progression on imaging after PVE, and three had inadequate FLR hypertrophy with no surgery. One major complication was observed related to PVE that involved nontarget embolization to segment III, which was managed conservatively.

CONCLUSIONS

Preoperative PVE with STS foam is a safe and effective method to induce hypertrophy of the FLR.

Liver segmentation: practical tips

The liver segmentation system, described by Couinaud, is based on the identification of the three hepatic veins and the plane passing by the portal vein bifurcation. Nowadays, Couinaud's description is the most widely used classification since it is better suited for surgery and more accurate for the localisation and monitoring of intra-parenchymal lesions. Knowledge of the anatomy of the portal and venous system is therefore essential, as is knowledge of the variants resulting from changes occurring during the embryological development of the vitelline and umbilical veins. In this paper, the authors propose a straightforward systematisation of the liver in six steps using several additional anatomical points of reference. These points of reference are simple and quickly identifiable in any radiological examination with section imaging, in order to avoid any mistakes in daily practice. In fact, accurate description impacts on many diagnostic and therapeutic applications in interventional radiology and surgery. This description will allow better preparation for biopsy, portal vein embolisation, transjugular intrahepatic portosystemic shunt, tumour resection or partial hepatectomy for transplantation. Such advance planning will reduce intra- and postoperative difficulties and complications.

Improved hypertrophy of future remnant liver after portal vein embolization with plugs, coils and particles

PURPOSE

To retrospectively analyze efficacy as measured by volume gain of future remnant liver (FRL) after right portal vein embolization (PVE) using particles only versus particles and additional central plug and/or coil (CP/C) embolization.

METHODS

All patients who underwent PVE between July 2011 and December 2012 were retrospectively analyzed. Right PVE was performed either with particle-only (PO) embolization or additional CP/C embolization. All enrolled patients underwent computed tomography or magnetic resonance imaging before PVE and surgery. The images were used for volumetry of the FRL.

RESULTS

Of 75 patients, 40 had PO and 35 CP/C embolization. Age, sex, and tumor entities did not differ significantly between the two groups. Tumor entities included cholangiocarcinoma (n = 52), metastasis from colorectal cancer (n = 14), hepatocellular carcinoma (n = 2), and others (n = 7). Time from PVE to preoperative imaging was similar in both groups. FRL volume before PVE was 329 ± 121 ml in the PO group and 333 ± 135 ml in the CP/C group, and 419 ± 135 ml and 492 ± 165 ml before operation. The average percentage volume gain was significantly higher in the CP/C group than in the PO group, with 53.3 ± 34.5 % versus 30.9 ± 28.8 % (p = 0.002).

CONCLUSION

Right PVE with additional CP/C embolization leads to a significantly higher gain in FRL volume than embolization with particles alone.

Preoperative portal vein embolization with a combination of trisacryl microspheres, gelfoam and coils

PURPOSE

To evaluate the safety and efficiency of preoperative portal vein embolization (PVE) with a combination of trisacryl microspheres, gelfoam and coils for inducing lobar hypertrophy in hepatobiliary malignancy patients.

MATERIALS AND METHODS

PVE was performed by a percutaneous left approach in 63 patients with hepatic malignancy (hepatocarcinoma=38, colorectal metastasis=14, cholangiocarcinoma=11). The indication of PVE and surgery was evaluated by hepatic tumor board take into consideration to the tumor extension and the hepatic volume on initial and post-embolization CT-scans. The total functional liver volume (TELV) and future liver remnant (FLR) volume were measured before and 24±5days after PVE to assess FLR, TELV and FLR/TELV ratios. Efficiency evaluation was based on FLR increase, the ability to perform the hepatectomy and the hepatic function after surgery. Safety evaluation was determined by clinical and biological follow-up after embolization and surgery.

RESULTS

PVE was successful in all the patients. The mean FLR volume increases by 57±56% after embolization (449±180cm(3) to 663±254cm(3)) (P<0.0001). The FLR/TELV ratio increases by 11% after PVE (25±8% to 36±12%). Three minors' complications were registered without impact on surgery, and four patients developed portal hypertension. Forty-nine patients underwent hepatectomy; none of them developed liver failure. Surgery was not performed in 14 patients due to tumor progression (n=9), inadequate hypertrophy of FLR (n=1) and portal hypertension (n=4).

CONCLUSION

Preoperative PVE with a combination of trisacryl microspheres, gelfoam and coils is a safe and effective method for inducing contralateral hypertrophy before right hepatectomy in patients with advanced hepatobiliary malignancy.

Simultaneous biliary drainage and portal vein embolization before extended hepatectomy for hilar cholangiocarcinoma: preliminary experience

BACKGROUND

Patients with resectable hilar cholangiocarcinoma often present obstructive jaundice and a small future remnant liver (FRL) ratio. A sequential approach comprising preoperative biliary drainage followed by portal vein embolization (PVE) is usually performed but leads to long preoperative management (6-12 weeks) before patients can undergo resection. To simplify and shorten this phase of liver preparation, we developed a new preoperative approach that involves percutaneous biliary drainage and PVE during the same procedure. We report the outcomes of this combined procedure.

METHODS

During 1 year, four patients underwent simultaneous biliary drainage and PVE followed 1 month later by surgical resection of hilar cholangiocarcinoma. Liver volumes were assessed by CT before, and 1, and 3 months after the combined procedure. Serum liver enzymes were assessed before and 1 month after the combined procedure.

RESULTS

The combined procedure was feasible in all cases, with no related complications. After the combined procedure, transaminases remained stable or decreased, whereas gamma-glutamyl-transpeptidase, alkaline phosphatase, and bilirubin decreased. During the first month, the left lobe volume increased by +27.9 % (range 19-40.9 %). The FRL ratio increased from 24.9 to 33.2 %. All patients underwent R0 liver resection with a favorable postoperative outcome. The remnant liver volume increased by +132 % (range 78-245 %) between 1 and 3 months.

CONCLUSIONS

Simultaneous percutaneous biliary drainage and PVE is feasible. This all-in-one preoperative approach greatly decreases waiting time until surgical resection. These encouraging results warrant further investigation to confirm the safety and to evaluate the reduction in the dropout rate for liver resection in this tumor with poor prognosis.