Simultaneous hepatic and portal vein ligation induces rapid liver hypertrophy: A study in pigs

Regional quantification of metabolic liver function using hyperpolarized [1-13C] pyruvate MRI

Assessment of liver function is essential before partial hepatectomy to predict the risk of post hepatectomy liver failure, a severe and life-threatening complication. Traditional methods have focused on expected future liver remnant (FLR) volume estimation. However, liver volume does not always correlate with function. We suggest that metabolism might be a better surrogate for function than volume. Therefore, we aimed to investigate the metabolic changes in a porcine model of partial portal vein ligation (PVL) using hyperpolarized magnetic resonance imaging (HP-MRI). Specifically, we sought to quantify and compare the pyruvate metabolism in the FLR and the deportalized liver (DL).Six pigs underwent PVL. HP-MRI with [1-13C] pyruvate was performed at baseline, post-surgery, and 1 week after surgery. Metabolic conversion was quantified with kinetic modelling of the rate constants of pyruvate to lactate (kPL) and pyruvate to alanine (kPA). Mean kPL was increased in FLR compared to DL at post-surgery and 1 week after surgery (P = 0.002), while kPA was unaltered (P = 0.761). These findings indicate a metabolic shift towards glycolysis in the FLR. This non-invasive metabolic imaging technique could serve as a powerful tool for evaluation of regional liver function prior to partial hepatectomy and consequently improve patient outcomes.

Portal and Hepatic Vein Embolization versus Portal Venous Embolization Alone in Cirrhotic and Noncirrhotic Swine: A Pilot Study

PURPOSE

To evaluate the effectiveness of combined portal vein embolization (PVE) and hepatic vein embolization (HVE) compared with that of PVE alone in cirrhotic and noncirrhotic swine.

MATERIALS AND METHODS

Sixteen Yorkshire pigs were included in this study. In the cirrhotic group (n = 8) and noncirrhotic group (n = 8), subjects underwent embolization according to established protocols. Computed tomography (CT) scans were acquired before and at 2- and 4-week intervals following the embolization. Liver volumes were segmented in the portal venous phase. Student t test with a significance level at P < .05 was used.

RESULTS

Across all swine, the future liver remnant (FLR) was significantly larger after PVE + HVE than after PVE at 2 weeks (24.12% [95% CI, 15.36%-32.88%] vs 12.75% [95% CI, 7.43%-18.07%]; P = .021) and 4 weeks (23.23% [95% CI, 15.79%-33.47%] vs 15.08% [95% CI, 9.98%-20.87%]; P = .043) after embolization. In the cirrhotic group, the FLR increase was greater following PVE + HVE than after PVE at 2 weeks (20.85% [95% CI, 14.40%-27.30%] vs 8.66% [95% CI, 6.47%-10.86%]; P = .0089) and 4 weeks (19.27% [95% CI, 17.87%-20.67%] vs 13.33% [95% CI, 9.23%-13.33%]; P = .0003) after embolization.

CONCLUSIONS

PVE + HVE resulted in greater FLR hypertrophy than PVE alone, indicating that cirrhotic livers may benefit from the addition of HVE.

Circulating proliferative factors versus portal inflow redistribution: mechanistic insights of ALPPS-derived rapid liver regeneration

Background

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) can induce accelerated regeneration of future liver remnant (FLR) and effectively reduce the occurrence of liver failure due to insufficient FLR after hepatectomy, thereby increasing the probability of radical resection for previously inoperable patients with liver cancer. However, the exact mechanism by which ALPPS accelerates liver regeneration remains elusive.

Methods

A review of the literature was performed utilizing MEDLINE/PubMed and Web of Science databases in March of 2024. The key words "liver regeneration/hypertrophy", "portal vein ligation/embolization", "two-stage hepatectomy", "liver partition/split" and "future liver remnant" in combination with "mechanisms", "hemodynamics", "cytokines", "growth factors" or "collaterals" were searched in the title and/or abstract. The references of relevant articles were reviewed to identify additional eligible publications.

Results

Previously, a widely accepted view is that the primary role of liver splitting in ALPPS stage 1 is to accelerate liver regeneration by promoting proliferative factor release, but increasing evidence in recent years reveal that not the circulating factors, but the portal hemodynamic alternations caused by liver parenchyma transection play a pivotal role in ALPPS-associated rapid liver hypertrophy.

Conclusion

Parenchyma transection-induced portal hemodynamic alternations are the main triggers or driving forces of accelerated liver regeneration following ALPPS. The release of circulating proliferative factors seems to be a secondary response to liver splitting and plays an auxiliary role in this process.

Histological and radiological analysis of simultaneous dual hepatic vein embolization for right-sided major hepatectomy

PURPOSE

Simultaneous dual hepatic vein embolization (DHVE) has been proposed for safe right-sided hepatectomy, with good results for liver hypertrophy and function. However, the histological and radiological findings of DHVE have not been thoroughly investigated.

METHODS

This study included 14 patients who underwent DHVE before right-sided major hepatectomy. DHVE was performed if the future liver remnant was < 35% or borderline, but with concomitant vascular resection. The liver function was assessed using the signal intensity on Gd-EOB-DTPA-MRI. A histological evaluation of the area of DHVE and portal vein embolization (PVE) were performed.

RESULTS

The median pre- and post-functional liver remnants were 363 ml and 498 ml, respectively (p < 0.001). The median growth rate was 48.6%, and there was no post-hepatectomy liver failure in the patients who underwent DHVE. The signal intensity ratio in the area of DHVE was lower than that in the areas of PVE and the remnant liver (p < 0.01). The degree of congestion and necrosis was greater in the area of DHVE than in the area of PVE alone (p < 0.01 and p = 0.04, respectively).

CONCLUSIONS

We observed good liver hypertrophy after DHVE and histological and radiological changes in the area of DHVE. Our findings provide a compelling rationale for further investigation of the mechanism of liver hypertrophy in DHVE.

Comprehensive Review of Future Liver Remnant (FLR) Assessment and Hypertrophy Techniques Before Major Hepatectomy: How to Assess and Manage the FLR

BACKGROUND

The regenerative capacities of the liver and improvements in surgical techniques have expanded the possibilities of resectability. Liver resection is often the only curative treatment for primary and secondary malignancies, despite the risk of post-hepatectomy liver failure (PHLF). This serious complication (with a 50% mortality rate) can be avoided by better assessment of liver volume and function of the future liver remnant (FLR).

OBJECTIVE

The aim of this review was to understand and assess clinical, biological, and imaging predictors of PHLF risk, as well as the various hypertrophy techniques, to achieve an adequate FLR before hepatectomy.

METHOD

We reviewed the state of the art in liver regeneration and FLR hypertrophy techniques.

RESULTS

The use of new biological scores (such as the aspartate aminotransferase/platelet ratio index + albumin-bilirubin [APRI+ALBI] score), concurrent utilization of 99mTc-mebrofenin scintigraphy (HBS), or dynamic hepatocyte contrast-enhanced MRI (DHCE-MRI) for liver volumetry helps predict the risk of PHLF. Besides portal vein embolization, there are other FLR optimization techniques that have their indications in case of risk of failure (e.g., associating liver partition and portal vein ligation for staged hepatectomy, liver venous deprivation) or in specific situations (transarterial radioembolization).

CONCLUSION

There is a need to standardize volumetry and function measurement techniques, as well as FLR hypertrophy techniques, to limit the risk of PHLF.

Efficacy of associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) in hepatocellular carcinoma with macrovascular invasion: a single-center retrospective analysis

Objective The influence of macrovascular invasion on the therapeutic efficacy of Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy (ALPPS) in hepatocellular carcinoma (HCC) patients has not been previously reported. This study primarily examines the therapeutic effect of ALPPS in treating HCC with macrovascular invasion. Methods 89 patients who underwent ALPPS at the First Affiliated Hospital of Guangxi Medical University from December 2016 to December 2021 were included. Patients were categorized into three groups based on macrovascular invasion status: pure HCC, HCC with portal vein tumor thrombus (PVTT), and HCC with hepatic vein tumor thrombus (HVTT). Outcome measures such as postoperative complications, liver hyperplasia rates, and survival times were compared across the groups. Results The study comprised 44 patients without macrovascular invasion and 45 cases with it, including 37 PVTT and 8 HVTT cases. Patients with PVTT or HVTT had a higher rate of complications and liver failure after the first ALPPS stage compared to those without macrovascular invasion (P = 0.018, P = 0.036). This trend was also observed in the stratified analysis of severe complications. However, no significant differences were found in these outcomes after the second ALPPS stage among the groups. The volume and rate of future liver remnant proliferation between the two stages of ALPPS were not statistically different among the groups, with median overall survival times of 42, 39, and 33 months, and progression-free survival times of 30, 24, and 14 months, respectively (P = 0.412 and P = 0.281). Conclusion ALPPS for HCC with macrovascular invasion was considered safe, feasible, and effective, as it achieved therapeutic effects comparable to those in cases without macrovascular invasion.

A systematic review and meta-analysis of liver venous deprivation versus portal vein embolization before hepatectomy: future liver volume, postoperative outcomes, and oncological safety

Introduction

This systematic review aimed to compare liver venous deprivation (LVD) with portal vein embolization (PVE) in terms of future liver volume, postoperative outcomes, and oncological safety before major hepatectomy.

Methods

We conducted this systematic review and meta-analysis following the PRISMA guidelines 2020 and AMSTAR 2 guidelines. Comparative articles published before November 2022 were retained.

Results

The literature search identified nine eligible comparative studies. They included 557 patients, 207 in the LVD group and 350 in the PVE group. This systematic review and meta-analysis concluded that LVD was associated with higher future liver remnant (FLR) volume after embolization, percentage of FLR hypertrophy, lower failure of resection due to low FLR, faster kinetic growth, higher day 5 prothrombin time, and higher 3 years' disease-free survival. This study did not find any difference between the LVD and PVE groups in terms of complications related to embolization, FLR percentage of hypertrophy after embolization, failure of resection, 3-month mortality, overall morbidity, major complications, operative time, blood loss, bile leak, ascites, post hepatectomy liver failure, day 5 bilirubin level, hospital stay, and three years' overall survival.

Conclusion

LVD is as feasible and safe as PVE with encouraging results making some selected patients more suitable for surgery, even with a small FLR.

Systematic review registration

The review protocol was registered in PROSPERO before conducting the study (CRD42021287628).

Extended Ligation of the Hepatic Vein May Yield a Similar Effect to Liver Venous Deprivation in a Rat Model

AIMS

To validate the hypothesis that hepatic vein ligation (HVL) alone may produce similar results to liver venous deprivation (LVD or HVL + portal vein ligation [PVL]).

METHODS

Rats were assigned to five groups, namely, the control group; the R group in which the right median hepatic vein (RMHV) was ligated; the M group in which the middle median hepatic vein (MMHV) was ligated; the RM group in which both the RMHV and MMHV were ligated (R + MMHVL, extended ligation of the hepatic veins); and the LVD group in which both the right median portal vein and the RMHV were ligated. The liver hypertrophy effect and liver enzymes were determined. Methylene blue staining and retrograde pressurized perfusion assays were performed to investigate the hemodynamic changes.

RESULTS

The RM and LVD groups exhibited similar significant hypertrophy in the future liver remnants when compared to that of the control group, and almost no additional hypertrophy effect was observed in the R and M groups. There was a remarkable elevation in serum transaminase levels in both groups. The methylene blue staining experiment indicated that pressure-dependent collaterals formed between the contiguous drainage areas, and the R + MMHVL procedure blocked the outflow of the right median lobe.

CONCLUSION

Extended ligation of the hepatic vein (R + MMHVL) resulted in a similar hypertrophy effect and hepatic damage to those of LVD (HVL + PVL) treatment in a rat model, and intrahepatic venovenous collaterals play key roles.

Extreme hepatectomy with modified ALPPS in a rat model: gradual portal vein restriction associated with hepatic artery restriction

BACKGROUND & AIM

Associating liver partition and portal vein ligation (PVL) for staged hepatectomy (ALPPS) is a creative strategy for enlarging the future liver remnant (FLR) and increasing the tumor resectability rate. However, the indications for ALPPS must have a certain limit when the FLR is too small. We aimed to establish a modified ALPPS model with more widen applicability in rats.

METHODS

An extreme ALPPS model was established in rodents with only a 6.5% FLR. The portal vein (PV) was subjected to restriction to different degrees, then the portal vein pressure (PVP) was measured. Then, different modifications of ALPPS, including hepatic artery restriction (HAR), gradual portal vein restriction (GPVR), and GPVR-associated HAR (HAR+GPVR), were applied in the extreme ALPPS models.

RESULTS

PVL or PVR provoked an immediate increase in the PVP. The PVP in the PVR -1.28 mm, PVR -0.81 mm, PVR -0.63 mm, and PVL groups was 11.05±1.57 cmH2O, 16.18±1.92 cmH2O, 20.66±1.99 cmH2O, and 24.10±3.33 cmH2O, respectively, and the corresponding 3-day survival rate was 100%, 90.09%, 36.33% and 0, respectively. Then, in the extreme ALPPS model, the growth ratio of the FLR in the control, HAR, GPVR, and HAR+GPVR groups was 0.43±0.21, 0.50±0.16, 4.80±0.86, and 7.40±2.56, and as a consequence, the corresponding 30-day survival rate was 9.09%, 15.38%, 84.61% and 92.90%, respectively.

CONCLUSION

ALPPS itself has a limit, and high PVP after PVL contributes to postoperative death in the extreme ALPPS model. Furthermore, a modified method for extreme ALPPS is proposed, i.e., GPVR+HAR in place of PVL, which significantly improves the survival rate of extreme hepatectomy in rat models.

Establishment of a Rat Model of Liver Venous Deprivation: Simultaneous Portal and Hepatic Vein Ligation

BACKGROUND AND AIMS

The aim was to establish a liver venous deprivation (LVD) model in rats, compare hepatic hypertrophy between LVD and associated liver partition and portal vein ligation for staged hepatectomy (ALPPS), and explore the underlying mechanisms.

METHODS

The LVD or extended-LVD (e-LVD) group received portal vein ligation (PVL) combined with hepatic vein ligation (HVL). The ALPPS or e-ALPPS group received PVL plus parenchyma ligation. Liver regeneration was assessed by measuring the liver weight and performing pathological analysis. Liver functions and the sphingosine kinase 1 (SPHK1)/sphingosine-1-phosphate (S1P)/sphingosine-1-phosphate receptor 1 (S1PR1) pathway were also investigated.

RESULTS

All future liver remnants (FLRs) in the ALPPS, e-ALPPS, LVD, and e-LVD groups exhibited significant hypertrophy compared with the control group. The LVD and e-LVD procedures induced similar liver hypertrophy than that in the corresponding ALPPS groups. Furthermore, the LVD and e-LVD methods led to obvious cytolysis in the venous-deprived lobes as well as a noticeable increase in serum transaminase levels, while no necrosis was observed in the ALPPS and e-ALPPS groups. SPHK1/S1P/S1PR1 pathway were distinctly activated after operation, especially in congestive/ischemic livers.

CONCLUSIONS

We describe the first rat model of LVD and e-LVD with simultaneously associated HVL and PVL. Compared with the ALPPS technique, the LVD or e-LVD procedure had a comparable overall effect on the hypertrophy response and a stronger effect on liver function. The SPHK1/S1P/S1PR1 pathway was involved in the LVD- or ALPPS-induced liver remodeling.

Surgical Models of Liver Regeneration in Pigs: A Practical Review of the Literature for Researchers

The remarkable capacity of regeneration of the liver is well known, although the involved mechanisms are far from being understood. Furthermore, limits concerning the residual functional mass of the liver remain critical in both fields of hepatic resection and transplantation. The aim of the present study was to review the surgical experiments regarding liver regeneration in pigs to promote experimental methodological standardization. The Pubmed, Medline, Scopus, and Cochrane Library databases were searched. Studies evaluating liver regeneration through surgical experiments performed on pigs were included. A total of 139 titles were screened, and 41 articles were included in the study, with 689 pigs in total. A total of 29 studies (71% of all) had a survival design, with an average study duration of 13 days. Overall, 36 studies (88%) considered partial hepatectomy, of which four were an associating liver partition and portal vein ligation for staged hepatectomy (ALPPS). Remnant liver volume ranged from 10% to 60%. Only 2 studies considered a hepatotoxic pre-treatment, while 25 studies evaluated additional liver procedures, such as stem cell application, ischemia/reperfusion injury, portal vein modulation, liver scaffold application, bio-artificial, and pharmacological liver treatment. Only nine authors analysed how cytokines and growth factors changed in response to liver resection. The most used imaging system to evaluate liver volume was CT-scan volumetry, even if performed only by nine authors. The pig represents one of the best animal models for the study of liver regeneration. However, it remains a mostly unexplored field due to the lack of experiments reproducing the chronic pathological aspects of the liver and the heterogeneity of existing studies.

A prospective study of sequential hepatic vein embolization after portal vein embolization in patients scheduled for right-sided major hepatectomy: Results of feasibility and surgical strategy using functional liver assessment

BACKGROUND

Hepatic vein embolization (HVE) added to portal vein embolization (PVE) can further increase future remnant liver volume (FRLV) compared with PVE alone. This study was aimed to evaluate feasibility of sequential HVE in a prospective trial and to verify surgical strategy using functional FRLV (fFRLV).

METHODS

Hepatic vein embolization was prospectively indicated for post-PVE patients scheduled for right-sided major hepatectomy if the resection limit of fFRLV using EOB-magnetic resonance imaging was not satisfied. The resection limit was fFRLV: 615 mL/m² for predicting post-hepatectomy liver failure. Patients who underwent sequential PVE-HVE (n = 12) were compared with those who underwent PVE alone (n = 31).

RESULTS

All patients underwent HVE with no severe complications. Median fFRLV increased from 396 (range: 251-581) to 634 (range: 422-740) mL/m² by sequential PVE-HVE. From PVE to HVE, both of FRLV (P < .001) and fFRLV (P = .005) significantly increased. The increased width of fFRLV was larger than that of FRLV after performing HVE. Median growth rate was 71.3 (range: 33.3-80.3) %, which was higher than that of PVE alone (27.0%, range: 6.0-78.0). All-cohort resection rate was 88.3%. Strategy of using fFRLV for the resection limit and performing HVE in patients with insufficient functional volume resulted in no liver failure in all patients who underwent hepatectomy.

CONCLUSIONS

Sequential HVE after PVE is feasible and safe, and HVE induced possibility of further liver growth and its functional improvement. Our surgical strategy using fFRLV may be justified.

Clinical strategy of conversion therapy and surgical treatment for liver metastases from colorectal cancer

Colorectal cancer is one of the common malignant tumors of the digestive system in clinical practice. Due to the anatomical characteristics of the colorectum itself, colorectal cancer is prone to liver metastasis. Approximately 15%-25% of colorectal cancer cases are complicated with liver metastasis at diagnosis, 15%-25% are complicated with liver metastasis after radical resection of colorectal cancer, and 80%-90% with liver metastasis cannot undergo radical resection initially. The 5-year survival rate is less than 5%, and liver metastasis is the main cause of death in patients with colorectal cancer. In recent years, with the clinical application of effective chemotherapy and molecular targeted drugs, as well as the rapid development of surgical techniques, an individualized safe, efficient, fast, treatment plan can be formulated according to patients' age, primary colorectal tumor location, degree of differentiation, Ras and B-Raf gene status, tumor size, number and distribution of metastases in the liver. By shrinking the tumor volume in the liver and increasing the residual liver volume, liver metastatic tumors can undergo surgical resection or disease-free status can be achieved in patients with liver metastasis. As a result, patients with colorectal liver metastases can achieve a 5-year survival rate of 30%-57%, which greatly improves the prognosis after operation. According to the postoperative adverse factors, individualized preventive measures are worked out to reduce the impact of adverse factors and improve the prognosis of patients with colorectal liver metastases. In this paper, we systematically discuss the clinical strategy of conversion therapy and surgical treatment for unresectable colorectal cancer liver metastases by reviewing the relevant domestic and foreign literature, so as to provide a theoretical reference for the selection of clinical treatment and program for patients with unresectable colorectal cancer liver metastases.

Simultaneous portal and hepatic vein embolization is better than portal embolization or ALPPS for hypertrophy of future liver remnant before major hepatectomy: A systematic review and network meta-analysis

BACKGROUND

Post-hepatectomy liver failure (PHLF) is the Achilles' heel of hepatic resection for colorectal liver metastases. The most commonly used procedure to generate hypertrophy of the functional liver remnant (FLR) is portal vein embolization (PVE), which does not always lead to successful hypertrophy. Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) has been proposed to overcome the limitations of PVE. Liver venous deprivation (LVD), a technique that includes simultaneous portal and hepatic vein embolization, has also been proposed as an alternative to ALPPS. The present study aimed to conduct a systematic review as the first network meta-analysis to compare the efficacy, effectiveness, and safety of the three regenerative techniques.

DATA SOURCES

A systematic search for literature was conducted using the electronic databases Embase, PubMed (MEDLINE), Google Scholar and Cochrane.

RESULTS

The time to operation was significantly shorter in the ALPPS cohort than in the PVE and LVD cohorts by 27 and 22 days, respectively. Intraoperative parameters of blood loss and the Pringle maneuver demonstrated non-significant differences between the PVE and LVD cohorts. There was evidence of a significantly higher FLR hypertrophy rate in the ALPPS cohort when compared to the PVE cohort, but non-significant differences were observed when compared to the LVD cohort. Notably, the LVD cohort demonstrated a significantly better FLR/body weight (BW) ratio compared to both the ALPPS and PVE cohorts. Both the PVE and LVD cohorts demonstrated significantly lower major morbidity rates compared to the ALPPS cohort. The LVD cohort also demonstrated a significantly lower 90-day mortality rate compared to both the PVE and ALPPS cohorts.

CONCLUSIONS

LVD in adequately selected patients may induce adequate and profound FLR hypertrophy before major hepatectomy. Present evidence demonstrated significantly lower major morbidity and mortality rates in the LVD cohort than in the ALPPS and PVE cohorts.

Current trends in regenerative liver surgery: Novel clinical strategies and experimental approaches

Liver resections are performed to cure patients with hepatobiliary malignancies and metastases to the liver. However, only a small proportion of patients is resectable, largely because only up to 70% of liver tissue is expendable in a resection. If larger resections are performed, there is a risk of post-hepatectomy liver failure. Regenerative liver surgery addresses this limitation by increasing the future liver remnant to an appropriate size before resection. Since the 1980s, this surgery has evolved from portal vein embolization (PVE) to a multiplicity of methods. This review presents an overview of the available methods and their advantages and disadvantages. The first use of PVE was in patients with large hepatocellular carcinomas. The increase in liver volume induced by PVE equals that of portal vein ligation, but both result only in a moderate volume increase. While awaiting sufficient liver growth, 20%–40% of patients fail to achieve resection, mostly due to the progression of disease. The MD Anderson Cancer Centre group improved the PVE methodology by adding segment 4 embolization (“high-quality PVE”) and demonstrated that oncological results were better than non-surgical approaches in this previously unresectable patient population. In 2012, a novel method of liver regeneration was proposed and called Associating Liver Partition and Portal vein ligation for Staged hepatectomy (ALPPS). ALPPS accelerated liver regeneration by a factor of 2–3 and increased the resection rate to 95%–100%. However, ALPPS fell short of expectations due to a high mortality rate and a limited utility only in highly selected patients. Accelerated liver regeneration, however, was there to stay. This is evident in the multiplicity of ALPPS modifications like radiofrequency or partial ALPPS. Overall, rapid liver regeneration allowed an expansion of resectability with increased perioperative risk. But, a standardized low-risk approach to rapid hypertrophy has been missing and the techniques used and in use depend on local expertise and preference. Recently, however, simultaneous portal and hepatic vein embolization (PVE/HVE) appears to offer both rapid hypertrophy and no increased clinical risk. While prospective randomized comparisons are underway, PVE/HVE has the potential to become the future gold standard.

Dragon 1 Protocol Manuscript: Training, Accreditation, Implementation and Safety Evaluation of Portal and Hepatic Vein Embolization (PVE/HVE) to Accelerate Future Liver Remnant (FLR) Hypertrophy

STUDY PURPOSE

The DRAGON 1 trial aims to assess training, implementation, safety and feasibility of combined portal- and hepatic-vein embolization (PVE/HVE) to accelerate future liver remnant (FLR) hypertrophy in patients with borderline resectable colorectal cancer liver metastases.

METHODS

The DRAGON 1 trial is a worldwide multicenter prospective single arm trial. The primary endpoint is a composite of the safety of PVE/HVE, 90-day mortality, and one year accrual monitoring of each participating center. Secondary endpoints include: feasibility of resection, the used PVE and HVE techniques, FLR-hypertrophy, liver function (subset of centers), overall survival, and disease-free survival. All complications after the PVE/HVE procedure are documented. Liver volumes will be measured at week 1 and if applicable at week 3 and 6 after PVE/HVE and follow-up visits will be held at 1, 3, 6, and 12 months after the resection.

RESULTS

Not applicable.

CONCLUSION

DRAGON 1 is a prospective trial to assess the safety and feasibility of PVE/HVE. Participating study centers will be trained, and procedures standardized using Work Instructions (WI) to prepare for the DRAGON 2 randomized controlled trial. Outcomes should reveal the accrual potential of centers, safety profile of combined PVE/HVE and the effect of FLR-hypertrophy induction by PVE/HVE in patients with CRLM and a small FLR.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT04272931 (February 17, 2020). Toestingonline.nl: NL71535.068.19 (September 20, 2019).

Induction of Robust Future Liver Remnant Hypertrophy Before Hepatectomy With a Modified Liver Venous Deprivation Technique Using a Trans-venous Access for Hepatic Vein Embolization

Purpose: Hepatic and/or portal vein embolization are performed before hepatectomy for patients with insufficient future liver remnant and usually achieved with a trans-hepatic approach. The aim of the present study is to describe a modified trans-venous liver venous deprivation technique (mLVD), avoiding the potential risks and limitations of a percutaneous approach to hepatic vein embolization, and to assess the safety, efficacy, and surgical outcome after mLVD. Materials and Methods: Retrospective single-center institutional review board-approved study. From March 2016 to June 2019, consecutive oncologic patients with combined portal and hepatic vein embolization were included. CT volumetric analysis was performed before and after mLVD to assess liver hypertrophy. Complications related to mLVD and surgical outcome were obtained from medical records. Results: Thirty patients (62.7 ± 14.5 years old, 20 men) with liver metastasis (60%) or primary liver cancer (40%) underwent mLVD. Twenty-one patients (70%) had hepatic vein anatomic variants. Technical success of mLVD was 100%. Four patients had complications (three minor and one major). FLR hypertrophy was 64.2% ± 51.3% (mean ± SD). Twenty-four patients (80%) underwent the planned hepatectomy and no surgery was canceled as a consequence of mLVD complications or insufficient hypertrophy. Fifty percent of patients (12/24) had no or mild complications after surgery (Clavien-Dindo 0-II), and 45.8% (11/24) had more serious complications (Clavien-Dindo III-IV). Thirty-day mortality was 4.2% (1/24). Conclusion: mLVD is an effective method to induce FLR hypertrophy. This technique is applicable in a wide range of oncologic situations and in patients with complex right liver vein anatomy.

Ligation of the middle hepatic vein to increase hypertrophy induction during the ALPPS procedure

PURPOSE

Here, we analyse the technical modification of the ALPPS procedure, ligating the middle hepatic vein during the first step of the operation to enhance remnant liver hypertrophy.

METHODS

In 20 of 37 ALPPS procedures, the middle hepatic vein was ligated during the first step. Hypertrophy of the functional remnant liver volume was assessed in addition to postoperative courses.

RESULTS

Volumetric analysis showed a significant volume increase, especially for patients with colorectal metastases. Pre-existing liver parenchyma damage (odds ratio = 0.717, p = 0.017) and preoperative chemotherapy were found to be significant predictors (odds ratio = 0.803, p = 0.045) of higher morbidity and mortality. In addition, a survival benefit for maintenance of middle hepatic vein was shown.

CONCLUSION

This technical modification of the ALPPS procedure can accentuate future liver remnant volume hypertrophy. The higher morbidity and mortality observed are most likely associated with pre-existing parenchymal damage within this group.

Induction of liver hypertrophy for extended liver surgery and partial liver transplantation: State of the art of parenchyma augmentation-assisted liver surgery

Background

Liver surgery and transplantation currently represent the only curative treatment options for primary and secondary hepatic malignancies. Despite the ability of the liver to regenerate after tissue loss, 25–30% future liver remnant is considered the minimum requirement to prevent serious risk for post-hepatectomy liver failure.

Purpose

The aim of this review is to depict the various interventions for liver parenchyma augmentation–assisting surgery enabling extended liver resections. The article summarizes one- and two-stage procedures with a focus on hypertrophy- and corresponding resection rates.

Conclusions

To induce liver parenchymal augmentation prior to hepatectomy, most techniques rely on portal vein occlusion, but more recently inclusion of parenchymal splitting, hepatic vein occlusion, and partial liver transplantation has extended the technical armamentarium. Safely accomplishing major and ultimately total hepatectomy by these techniques requires integration into a meaningful oncological concept. The advent of highly effective chemotherapeutic regimen in the neo-adjuvant, interstage, and adjuvant setting has underlined an aggressive surgical approach in the given setting to convert formerly “palliative” disease into a curative and sometimes in a “chronic” disease.

Preoperative portal vein or portal and hepatic vein embolization: DRAGON collaborative group analysis

BACKGROUND

The extent of liver resection for tumours is limited by the expected functional reserve of the future liver remnant (FRL), so hypertrophy may be induced by portal vein embolization (PVE), taking 6 weeks or longer for growth. This study assessed the hypothesis that simultaneous embolization of portal and hepatic veins (PVE/HVE) accelerates hypertrophy and improves resectability.

METHODS

All centres of the international DRAGON trials study collaborative were asked to provide data on patients who had PVE/HVE or PVE on 2016-2019 (more than 5 PVE/HVE procedures was a requirement). Liver volumetry was performed using OsiriX MD software. Multivariable analysis was performed for the endpoints of resectability rate, FLR hypertrophy and major complications using receiver operating characteristic (ROC) statistics, regression, and Kaplan-Meier analysis.

RESULTS

In total, 39 patients had undergone PVE/HVE and 160 had PVE alone. The PVE/HVE group had better hypertrophy than the PVE group (59 versus 48 per cent respectively; P = 0.020) and resectability (90 versus 68 per cent; P = 0.007). Major complications (26 versus 34 per cent; P = 0.550) and 90-day mortality (3 versus 16 per cent respectively, P = 0.065) were comparable. Multivariable analysis confirmed that these effects were independent of confounders.

CONCLUSION

PVE/HVE achieved better FLR hypertrophy and resectability than PVE in this collaborative experience.

Deportalization, Venous Congestion, Venous Deprivation: Serial Measurements of Volumes and Functions on Morphofunctional 99mTc-Mebrofenin SPECT-CT

The objective was to assess the changes in regional volumes and functions under venous-impaired vascular conditions following liver preparation. Twelve patients underwent right portal vein embolization (PVE) (n = 5) or extended liver venous deprivation (eLVD, i.e., portal and right and middle hepatic veins embolization) (n = 7). Volume and function measurements of deportalized liver, venous-deprived liver and congestive liver were performed before and after PVE/eLVD at days 7, 14 and 21 using 99mTc-mebrofenin hepatobiliary scintigraphy with single-photon emission computed tomography and computed tomography (99mTc-mebrofenin SPECT-CT). Volume and function progressed independently in the deportalized liver (p = 0.47) with an early decrease in function (median −18.2% (IQR, −19.4–−14.5) at day 7) followed by a decrease in volume (−19.3% (−22.6–−14.4) at day 21). Volume and function progressed independently in the venous deprived liver (p = 0.80) with a marked and early decrease in function (−41.1% (−52.0–−12.9) at day 7) but minimal changes in volume (−4.7% (−10.4–+3.9) at day 21). Volume and function progressed independently in the congestive liver (p = 0.21) with a gradual increase in volume (+43.2% (+38.3–+51.2) at day 21) that preceded a late and moderate increase in function at day 21 (+34.8% (−8.3–+46.6)), concomitantly to the disappearance of hypoattenuated congestive areas in segment IV (S4) on CT, initially observed in 6/7 patients after eLVD and represented 35.3% (22.2–46.4) of whole S4 volume. Liver volume and function progress independently whatever the vascular condition. Hepatic congestion from outflow obstruction drives volume increase but results in early impaired function.

Liver venous deprivation versus portal vein embolization before major hepatectomy: future liver remnant volumetric and functional changes

Background

We previously showed that embolization of portal inflow and hepatic vein (HV) outflow (liver venous deprivation, LVD) promotes future liver remnant (FLR) volume (FLR-V) and function (FLR-F) gain. Here, we compared FLR-V and FLR-F changes after portal vein embolization (PVE) and LVD.

Methods

This study included all patients referred for liver preparation before major hepatectomy over 26 months. Exclusion criteria were: unavailable baseline/follow-up imaging, cirrhosis, Klatskin tumor, two-stage hepatectomy. 99mTc-mebrofenin SPECT-CT was performed at baseline and at day 7, 14 and 21 after PVE or LVD. FLR-V and FLR-F variations were compared using multivariate generalized linear mixed models (joint modelling) with/without missing data imputation.

Results

Baseline FLR-F was lower in the LVD (n=29) than PVE group (n=22) (P<0.001). Technical success was 100% in both groups without any major complication. Changes in FLR-V at day 14 and 21 (+14.2% vs. +50%, P=0.002; and +18.6% vs. +52.6%, P=0.001), and in FLR-F at day 7, 14 and 21 (+23.1% vs. +54.3%, P=0.02; +17.6% vs. +56.1%, P=0.006; and +29.8% vs. +63.9%, P<0.001) differed between PVE and LVD group. LVD (P=0.009), age (P=0.027) and baseline FLR-V (P=0.001) independently predicted FLR-V variations, whereas only LVD (P=0.01) predicted FLR-F changes. After missing data handling, LVD remained an independent predictor of FLR-V and FLR-F variations.

Conclusions

LVD is safe and provides greater FLR-V and FLR-F increase than PVE. These results are now evaluated in the HYPERLIV-01 multicenter randomized trial.

Simultaneous portal and hepatic vein embolization before major liver resection

Background

Regenerative liver surgery expands the limitations of technical resectability by increasing the future liver remnant (FLR) volume before extended resections in order to avoid posthepatectomy liver failure (PHLF). Portal vein rerouting with ligation of one branch of the portal vein bifurcation (PVL) or embolization (PVE) leads to a moderate liver volume increase over several weeks with a clinical dropout rate of 20–40%, mostly due to tumor progression during the waiting period. Accelerated liver regeneration by the Associating Liver Partition and Portal vein Ligation for Staged hepatectomy (ALPPS) was poised to overcome this limitation by reduction of the waiting time, but failed due increased perioperative complications. Simultaneous portal and hepatic vein embolization (PVE/HVE) is a novel minimal invasive way to induce rapid liver growth without the need of two surgeries.

Purpose

This article summarizes published results of PVE/HVE and analyzes what is known about its efficacy to achieve resection, safety, and the volume changes induced.

Conclusions

PVE/HVE holds promise to induce accelerated liver regeneration in a similar safety profile to PVE. The demonstrated accelerated hypertrophy may increase resectability. Randomized trials will have to compare PVE/HVE and PVE to determine if PVE/HVE is superior to PVE.

Hypoxia sensing by hepatic stellate cells leads to VEGF-dependent angiogenesis and may contribute to accelerated liver regeneration

Portal vein ligation (PVL) induces liver growth prior to resection. Associating liver partition and portal vein ligation (PVL plus transection=ALPPS) or the addition of the prolyl-hydroxylase inhibitor dimethyloxalylglycine (DMOG) to PVL both accelerate growth via stabilization of HIF-α subunits. This study aims at clarifying the crosstalk of hepatocytes (HC), hepatic stellate cells (HSC) and liver sinusoidal endothelial cells (LSEC) in accelerated liver growth. In vivo, liver volume, HC proliferation, vascular density and HSC activation were assessed in PVL, ALPPS, PVL+DMOG and DMOG alone. Proliferation of HC, HSC and LSEC was determined under DMOG in vitro. Conditioned media experiments of DMOG-exposed cells were performed. ALPPS and PVL+DMOG accelerated liver growth and HC proliferation in comparison to PVL. DMOG alone did not induce HC proliferation, but led to increased vascular density, which was also observed in ALPPS and PVL+DMOG. Activated HSC were detected in ALPPS, PVL+DMOG and DMOG, again not in PVL. In vitro, DMOG had no proliferative effect on HC, but conditioned supernatant of DMOG-treated HSC induced VEGF-dependent proliferation of LSEC. Transcriptome analysis confirmed activation of proangiogenic factors in hypoxic HSC. Hypoxia signaling in HSC induces VEGF-dependent angiogenesis. HSC play a crucial role in the cellular crosstalk of rapid liver regeneration.

Perioperative impact of liver venous deprivation compared with portal venous embolization in patients undergoing right hepatectomy: preliminary results from the pioneer center

Background

Preoperative portal vein embolization (PVE) is currently the standard technique used routinely to increase the size of the future remnant liver (FRL) before major hepatectomies. The degree of hypertrophy (DH) is approximatively 10% and requires on average six weeks. ALPPS is faster and achieves a good DH but with a higher morbidity and mortality. One method recently proposed to increase the FRL is liver venous deprivation (LVD), but its clinical and operative impact is still unknown. The aim of this study is to compare intra- and postoperative morbidity/mortality and the histological evaluation of the liver parenchyma between PVE and LVD in patients undergoing anatomic right hepatectomy.

Methods

Fifty-three consecutive patients undergoing PVE and LVD before a major hepatectomy were retrospectively analysed between 2015 and 2017. In order to reduce the bias, only potential standard right hepatectomies were selected. Surgical resections and the radiologic procedures were performed by the same Institution. Intra-operative parameters (transfusions, perfusions, bleeding, operative time), postoperative complications (Clavien-Dindo and ISGLS criteria), and histological findings were compared.

Results

To induce FRL growth 16 patients underwent PVE and 13 LVD. One patient of the PVE group was not resected due to peritoneal metastases. Surgery was performed for hepatocellular carcinoma (PVE =9, LVD =3), metastases (PVE =5, LVD =10), or others diseases (PVE =2, LVD =0). Per- and post-operative morbidity/mortality rates after PVE and LVD procedures were null. No differences between the two groups were found in terms of intraoperative bleeding (median: 550 vs. 1,200 mL; P=0.36), hepatic pedicle clamping (5 vs. 3 patients; P=0.69), intraoperative red blood cells transfusions (median: 622 vs. 594; P=0.42) and operative time (median: 270 vs. 330 min; P=0.34). Post-operative course was similar when comparing both medical and surgical complications in the two arms (PVE n=7, LVD n=10, P=0.1). Major complications (Clavien-Dindo ≥ IIIa) occurred in 3 patients undergoing PVE and in 1 patient of the LVD group (P=0.6). No difference in biliary leak (P=0.1), haemorrhage (P=0.2) and liver failure (P=0.64) was found. One cirrhotic patient in the group of PVE died of post-operative liver failure due to left portal vein thrombosis. Although we experienced a more marked liver damage when assessing on neoplastic liver parenchyma, no statistical difference was observed in terms of atrophy (P=0.19), necrosis (P=0.5), hemorrhage (P=0.42) and sinusoidal dilatation (P=0.69).

Conclusions

Despite the limitations of our study, to our knowledge this is the first report to compare the two techniques LVD is a promising and safe procedure to induce a fast FRL hypertrophy, showing similar mortality/morbidity rates during and after surgery compared to PVE.