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

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.

Current Perspectives and Progress in Preoperative Portal Vein Embolization with Stem Cell Augmentation (PVESA)

Portal vein embolization with stem cell augmentation (PVESA) is an emerging approach for enhancing the growth of the liver segment that will remain after surgery (i.e., future liver remnant, FLR) in patients with liver cancer. Conventional portal vein embolization (PVE) aims to induce preoperative FLR growth, but it has a risk of failure in patients with underlying liver dysfunction and comorbid illnesses. PVESA combines PVE with stem cell therapy to potentially improve FLR size and function more effectively and efficiently. Various types of stem cells can help improve liver growth by secreting paracrine signals for hepatocyte growth or by transforming into hepatocytes. Mesenchymal stem cells (MSCs), unrestricted somatic stem cells, and small hepatocyte-like progenitor cells have been used to augment liver growth in preclinical animal models, while clinical studies have demonstrated the benefit of CD133 + bone marrow-derived MSCs and hematopoietic stem cells. These investigations have shown that PVESA is generally safe and enhances liver growth after PVE. However, optimizing the selection, collection, and application of stem cells remains crucial to maximize benefits and minimize risks. Additionally, advanced stem cell technologies, such as priming, genetic modification, and extracellular vesicle-based therapy, that could further enhance efficacy outcomes should be evaluated. Despite its potential, PVESA requires more investigations, particularly mechanistic studies that involve orthotopic animal models of liver cancer with concomitant liver injury as well as larger human trials.

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.

Assessment of Segmentary Hypertrophy of Future Remnant Liver after Liver Venous Deprivation: A Single-Center Study

Background: Liver venous deprivation (LVD) is a recent radiological technique that has shown promising results on Future Remnant Liver (FRL) hypertrophy. The aim of this retrospective study is to compare the segmentary hypertrophy of the FRL after LVD and after portal vein embolization (PVE). Methods: Patients undergoing PVE or LVD between April 2015 and April 2020 were included. The segmentary volumes (seg 4, seg2+3 and seg1) were assessed before and after the radiological procedure. Results: Forty-four patients were included: 26 undergoing PVE, 10 LVD and 8 eLVD. Volume gain of both segment 1 and segments 2+3 was significantly higher after LVD and eLVD than after PVE (segment 1: 27.33 ± 35.37 after PVE vs. 38.73% ± 13.47 after LVD and 79.13% ± 41.23 after eLVD, p = 0.0080; segments 2+3: 40.73% ± 40.53 after PVE vs. 45.02% ± 21.53 after LVD and 85.49% ± 45.51 after eLVD, p = 0.0137), while this was not true for segment 4. FRL hypertrophy was confirmed to be higher after LVD and eLVD than after PVE (33.53% ± 21.22 vs. 68.63% ± 42.03 vs. 28.11% ± 28.33, respectively, p = 0.0280). Conclusions: LVD and eLVD may induce greater hypertrophy of segment 1 and segments 2+3 when compared to PVE.

Multi-organ Radiomics-Based Prediction of Future Remnant Liver Hypertrophy Following Portal Vein Embolization

BACKGROUND

Portal vein embolization (PVE) is used to induce remnant liver hypertrophy prior to major hepatectomy. The purpose of this study was to evaluate the predictive value of baseline computed tomography (CT) data for future remnant liver (FRL) hypertrophy after PVE.

METHODS

In this retrospective study, all consecutive patients undergoing right-sided PVE with or without hepatic vein embolization between 2018 and 2021 were included. CT volumetry was performed before and after PVE to assess standardized FRL volume (sFRLV). Radiomic features were extracted from baseline CT after segmenting liver (without tumor), spleen and bone marrow. For selecting features that allow classification of response (hypertrophy ≥ 1.33), a stepwise dimension reduction was performed. Logistic regression models were fitted and selected features were tested for their predictive value. Decision curve analysis was performed on the test dataset.

RESULTS

A total of 53 patients with liver tumor were included in this study. sFRLV increased significantly after PVE, with a mean hypertrophy of FRL of 1.5 ± 0.3-fold. sFRLV hypertrophy ≥ 1.33 was reached in 35 (66%) patients. Three independent radiomic features, i.e. liver-, spleen- and bone marrow-associated, differentiated well between responders and non-responders. A logistic regression model revealed the highest accuracy (area under the curve 0.875) for the prediction of response, with sensitivity of 1.0 and specificity of 0.5. Decision curve analysis revealed a positive net benefit when applying the model.

CONCLUSIONS

This proof-of-concept study provides first evidence of a potential predictive value of baseline multi-organ radiomics CT data for FRL hypertrophy after PVE.

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.

Influence of cholestasis on portal vein embolization-induced hypertrophy of the future liver remnant

PURPOSE

In the pre-clinical setting, hepatocellular bile salt accumulation impairs liver regeneration following partial hepatectomy. Here, we study the impact of cholestasis on portal vein embolization (PVE)-induced hypertrophy of the future liver remnant (FLR).

METHODS

Patients were enrolled with perihilar cholangiocarcinoma (pCCA) or colorectal liver metastases (CRLM) undergoing PVE before a (extended) right hemihepatectomy. Volume of segments II/III was considered FLR and assessed on pre-embolization and post-embolization CT scans. The degree of hypertrophy (DH, percentual increase) and kinetic growth rate (KGR, percentage/week) were used to assess PVE-induced hypertrophy.

RESULTS

A total of 50 patients (31 CRLM, 19 pCCA) were included. After PVE, the DH and KGR were similar in patients with CRLM and pCCA (5.2 [3.3-6.9] versus 5.7 [3.2-7.4] %, respectively, p = 0.960 for DH; 1.4 [0.9-2.5] versus 1.9 [1.0-2.4] %/week, respectively, p = 0.742 for KGR). Moreover, pCCA patients with or without hyperbilirubinemia had comparable DH (5.6 [3.0-7.5] versus 5.7 [2.4-7.0] %, respectively, p = 0.806) and KGR (1.7 [1.0-2.4] versus 1.9 [0.8-2.4] %/week, respectively, p = 1.000). For patients with pCCA, unilateral drainage in FLR induced a higher DH than bilateral drainage (6.7 [4.9-7.9] versus 2.7 [1.5-4.2] %, p = 0.012). C-reactive protein before PVE was negatively correlated with DH (ρ = - 0.539, p = 0.038) and KGR (ρ = - 0.532, p = 0.041) in patients with pCCA.

CONCLUSIONS

There was no influence of cholestasis on FLR hypertrophy in patients undergoing PVE. Bilateral drainage and inflammation appeared to be negatively associated with FLR hypertrophy. Further prospective studies with larger and more homogenous patient cohorts are desirable.

Impact of sarcopenia on the future liver remnant growth after portal vein embolization and associating liver partition and portal vein ligation for staged hepatectomy in patients with liver cancer: A systematic review

Purpose

The impact of sarcopenia on the future liver remnant (FLR) growth after portal vein occlusion, including portal vein embolization (PVE) and associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) has gained increasing interest. This systematic review aimed to explore whether sarcopenia was associated with insufficient FLR growth after PVE/ALPPS stage-1.

Methods

A systematic literature search was performed in PubMed, Embase, Web of Science, and Cochrane Library up to 05 July 2022. Studies evaluating the influence of sarcopenia on FLR growth after PVE/ALPPS stage-1 in patients with liver cancer were included. A predefined table was used to extract information including the study and patient characteristics, sarcopenia measurement, FLR growth, post-treatment complications and post-hepatectomy liver failure, resection rate. Research quality was evaluated by the Newcastle-Ottawa Scale.

Results

Five studies consisting of 609 patients were included in this study, with a sample size ranging from 42 to 306 (median: 90) patients. Only one study was multicenter research. The incidence of sarcopenia differed from 40% to 67% (median: 63%). Skeletal muscle index based on pretreatment computed tomography was the commonly used parameter for sarcopenia evaluation. All included studies showed that sarcopenia impaired the FLR growth after PVE/ALPPS stage-1. However, the association between sarcopenia and post-treatment complications, post-hepatectomy liver failure, and resection rate remains unclear. All studies showed moderate-to-high quality.

Conclusions

Sarcopenia seems to be prevalent in patients undergoing PVE/ALPPS and may be a risk factor for impaired liver growth after PVE/ALPPS stage-1 according to currently limited evidence.

Systematic review registration

https://inplasy.com/, identifier INPLASY202280038.

Portal vein embolization failure: Current strategies and future perspectives to improve liver hypertrophy before major oncological liver resection

Portal vein embolization (PVE) is currently considered the standard of care to improve the volume of an inadequate future remnant liver (FRL) and decrease the risk of post-hepatectomy liver failure (PHLF). PHLF remains a significant limitation in performing major liver surgery and is the main cause of mortality after resection. The degree of hypertrophy obtained after PVE is variable and depends on multiple factors. Up to 20% of patients fail to undergo the planned surgery because of either an inadequate FRL growth or tumor progression after the PVE procedure (usually 6-8 wk are needed before surgery). The management of PVE failure is still debated, with a lack of consensus regarding the best clinical strategy. Different additional techniques have been proposed, such as sequential transarterial chemoembolization followed by PVE, segment 4 PVE, intra-portal administration of stem cells, dietary supplementation, and hepatic vein embolization. The aim of this review is to summarize the up-to-date strategies to overcome such difficult situations and discuss future perspectives on improving FRL hypertrophy.

Increased future liver function after modified associating liver partition and portal vein ligation/embolization for staged hepatectomy

Background

The increasing ratio of functional future liver remnant (functional %FLR) after modified associating liver partition and portal vein ligation/embolization for staged hepatectomy (modified-ALPPS) compared with portal vein embolization (PVE) has not been comprehensively evaluated.

Purpose

To compare the increasing ratio of functional %FLR between modified-ALPPS and PVE via technetium-99 m-galactosyl human serum albumin single-photon emission computed tomography (^99mTc-GSA SPECT/CT) fusion imaging.

Material and Methods

Seven and six patients underwent modified-ALPPS (modified-ALPPS group) and PVE (PVE group) from 2015 to 2019. The functional %FLR on 99 mTc-GSA SPECT/CT fusion imaging was assessed before and 1 week (modified-ALPPS group) and 3 weeks (PVE group) after each procedure. The increasing ratio of functional %FLR (functional %FLR ratio) was calculated and compared between the two groups. Moreover, the hypertrophy ratio of future liver remnant volume (FLRV ratio) and atrophy ratio of embolized liver volume (.ELV ratio) were evaluated.

Results

The mean functional %FLR ratios of the modified-ALPPS group (1.47 ± 0.15) and the PVE group (1.49 ± 0.20) were comparable (p > .05). The median FLRV ratio of modified-ALPPS group (1.48) was higher than that of the PVE group (1.16), the median ELV ratio of the PVE group (0.81) was lower than that of the modified-ALPPS group (0.94), and the results significantly differed between the two groups (p < .05).

Conclusion

The increasing ratio of functional %FLR was comparable between modified-ALPPS and PVE. Compared with PVE, ALPPS was associated with a higher hypertrophy rate of the remnant liver but a lower atrophy rate of the embolized liver.