Liver Hypertrophy After Percutaneous Portal Vein Embolization: Comparison of N-Butyl-2-Cyanocrylate Versus Sodium Acrylate–Vinyl Alcohol Copolymer Particles in a Swine Model

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.

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.

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.

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.

Vascular input function correction of inflow enhancement for improved pharmacokinetic modeling of liver DCE-MRI

PURPOSE

To propose a simple method to correct vascular input function (VIF) due to inflow effects and to test whether the proposed method can provide more accurate VIFs for improved pharmacokinetic modeling.

METHODS

A spoiled gradient echo sequence-based inflow quantification and contrast agent concentration correction method was proposed. Simulations were conducted to illustrate improvement in the accuracy of VIF estimation and pharmacokinetic fitting. Animal studies with dynamic contrast-enhanced MR scans were conducted before, 1 week after, and 2 weeks after portal vein embolization (PVE) was performed in the left portal circulation of pigs. The proposed method was applied to correct the VIFs for model fitting. Pharmacokinetic parameters fitted using corrected and uncorrected VIFs were compared between different lobes and visits.

RESULTS

Simulation results demonstrated that the proposed method can improve accuracy of VIF estimation and pharmacokinetic fitting. In animal study results, pharmacokinetic fitting using corrected VIFs demonstrated changes in perfusion consistent with changes expected after PVE, whereas the perfusion estimates derived by uncorrected VIFs showed no significant changes.

CONCLUSION

The proposed correction method improves accuracy of VIFs and therefore provides more precise pharmacokinetic fitting. This method may be promising in improving the reliability of perfusion quantification. Magn Reson Med 79:3093-3102, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

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.

Triggered liver regeneration: from experimental model to clinical implications

BACKGROUND

Major liver resection is the only therapeutic option for patients with malignant liver tumors. However, extended hepatectomy often leads to postoperative liver failure, mainly due to insufficient amounts of the remnant liver. Recently, selective portal vein occlusion (PVO) has been introduced to increase the remnant liver volume. This novel surgical technique initiated a progressive development in liver surgery, resulting in a significant increment in potential candidates for curative liver resection.

SUMMARY

The theoretical basis for this great advancement is formed by an understanding of the mechanisms of PVO-induced liver regeneration, mainly obtained from animal studies. The aim of this review is to give a comprehensive overview of the relevant animal models of PVO and to discuss the main characteristics of triggered liver regeneration, including the induced hemodynamic, morphological and functional alterations as well as the underlying molecular mechanisms, which might be of interest in both the laboratory and the clinic. Key Messages: Although basic research revealed the main characteristics of PVO-triggered liver regeneration within the last decades, several important issues regarding the regenerative process remain uncertain. To answer these open questions, additional well-designed animal experiments are needed in the future, which allow further refinement of this surgical technique.

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 using absolute ethanol: evaluation of its safety and efficacy

BACKGROUND

Previously, we reported on the clinical efficacy and safety of portal vein embolization (PVE) with fibrin glue. Our embolic materials for PVE changed from fibrin glue to absolute ethanol (EOH) after 2001 due to prohibition of using fibrin glue for PVE. With introducing our technique of PVE with EOH, we evaluated its safety and efficacy with attention to the amount of EOH.

METHODS

The medical records of 154 patients who underwent PVE using EOH were retrospectively reviewed.

RESULTS

Changes with time in both the serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) after PVE returned to the initial condition within 7 days after PVE. In the 96 patients who underwent CT volumerty 14 to 21 days after PVE, the volume of the embolized lobe decreased from 701 ± 165 cm(3) to 549 ± 148 cm(3) (P < 0.0001). Meanwhile, the volume of the non-embolized lobe increased from 388 ± 105 cm(3) to 481 ± 113 cm(3) (P < 0.0001). On simple linear regression, the amount of EOH was positively correlated with both the maximum of AST and that of ALT after PVE; however, it never correlated with changes in liver volume after PVE.

CONCLUSIONS

Portal vein embolization with EOH has a substantial effect on both hypertrophy of the non-embolized lobe and atrophy of the embolized lobe. Quick recoveries of changes with time in AST and ALT after PVE proved that PVE with EOH is a safe procedure. The amount of EOH affected the extent of liver damage but had no clinical effects on changes in liver volume after PVE.

Interventional oncologic approaches to liver metastases

Metastatic liver disease is the most common cause of death in cancer patients. Complete surgical resection is currently considered the only curative treatment, with only about 25% of patients being amenable to surgery. Therefore, a variety of interventional oncologic techniques have been developed for treating secondary liver malignancies. The aim of these therapies is either to allow patients with unresectable tumors to become surgical candidates, provide curative treatment options in nonsurgical candidates, or improve survival in a palliative or even curative approach. Among these interventional therapies are transcatheter therapies such as portal vein embolization, hepatic artery infusion chemotherapy, transarterial chemoembolization, and radioembolization, as well as interstitial techniques, particularly radiofrequency ablation as the most commonly applied technique. The rationale, application and clinical results of each of these techniques are reviewed on the basis of the current literature. Future prospects such as gene therapy and immunotherapy are introduced.