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

Transfemoral hepatic vein access in double vein embolization - initial experience and feasibility

BACKGROUND

Hepatic vein embolization in double vein embolization (DVE) can be performed with transhepatic, transjugular or transfemoral access. This study evaluates the feasibility and technical success of using a transfemoral access for the hepatic vein embolization in patients undergoing preoperative to induce hypertrophy of the future liver remnant (FLR).

MATERIAL AND METHODS

Retrospective analysis of single center cohort including 17 consecutive patients. The baseline standardized FLR was 18.2% (range 14.7-24.9). Portal vein embolization was performed with vascular plugs and glue through an ipsilateral transhepatic access. Hepatic vein embolization was performed using vascular plugs. Access for the hepatic vein was either transhepatic, transjugular or transfemoral. Technical success, number of hepatic veins embolized and complications were registered. In addition, volumetric data including degree of hypertrophy (DH) and kinetic growth rate (KGR), and resection data were registered. R: Seven of the 17 patients had transfemoral hepatic vein embolization, with 100% technical success. No severe complications were registered. In the whole cohort, the median number of hepatic veins embolized was 2 (1-6). DH was 8.6% (3.0-19.4) and KGR was 3.6%/week (1.4-7.4), without significant differences between the patients having transfemoral versus transhepatic /transjugular access (p = 0.48 and 0.54 respectively). Time from DVE to surgery was median 4.8 weeks (2.6-33.9) for the whole cohort, with one patient declining surgery, two having explorative laparotomy and one patient having change of surgical strategy due to insufficient growth.

CONCLUSION

Transfemoral access is a feasible option with a high degree of technical success for hepatic vein embolization in patients with small future liver remnants needing DVE.

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.

Evaluation of liver regeneration after hemi-hepatectomy by combining computed tomography and post-operative liver function

Background

Accurate evaluation of postoperative liver regeneration is essential to prevent postoperative liver failure.

Aims

To analyze the predictors that affect liver regeneration after hemi-hepatectomy.

Method

Patients who underwent hemi-hepatectomy in Hangzhou First People's Hospital and Hangzhou Shulan Hospital from January 2016 to December 2021 were enrolled in this study. The regeneration index (RI) was calculated by the following equation: RI = [(postoperative total liver volume {TLVpost} - future liver remnant volume {FLRV}/FLRV] × 100 %. Hepatic dysfunction was defined according to the "TBilpeak>7" standard, which was interpreted as (peak) total bilirubin (TBil) >7.0 mg/dL. Good liver regeneration was defined solely when the RI surpassed the median with hepatic dysfunction. Logistic regression analyses were performed to estimate prognostic factors affecting liver regeneration.

Result

A total of 153 patients were enrolled, with 33 in the benign group and 120 patients in the malignant group. In the entire study population, FLRV% [OR 4.087 (1.405-11.889), P = 0.010], international normalized ratio (INR) [OR 2.763 (95%CI, 1.008-7.577), P = 0.048] and TBil [OR 2.592 (95%CI, 1.177-5.710), P = 0.018] were independent prognostic factors associated with liver regeneration. In the benign group, only the computed tomography (CT) parameter FLRV% [OR, 11.700 (95%CI, 1.265-108.200), P = 0.030] predicted regeneration. In the malignant group, parenchymal hepatic resection rate (PHRR%) [OR 0.141 (95%CI, 0.040-0.499), P = 0.002] and TBil [OR 3.384 (95%CI, 1.377-8.319), P = 0.008] were independent prognostic factors.

Conclusion

FLRV%, PHRR%, TBil and INR were predictive factors associated with liver regeneration.

Liver volumetry and liver-regenerative interventions: history, rationale, and emerging tools

BACKGROUND

Postoperative hepatic insufficiency (PHI) is the most feared complication after hepatectomy. Volume of the future liver remnant (FLR) is one objectively measurable indicator to identify patients at risk of PHI. In this review, we summarized the development and rationale for the use of liver volumetry and liver-regenerative interventions and highlighted emerging tools that could yield new advancements in liver volumetry.

METHODS

A review of MEDLINE/PubMed, Embase, and Cochrane Library databases was conducted to identify literature related to liver volumetry. The references of relevant articles were reviewed to identify additional publications.

RESULTS

Liver volumetry based on radiologic imaging was developed in the 1980s to identify patients at risk of PHI and later used in the 1990s to evaluate grafts for living donor living transplantation. The field evolved in the 2000s by the introduction of standardized FLR based on the hepatic metabolic demands and in the 2010s by the introduction of the degree of hypertrophy and kinetic growth rate as measures of the FLR regenerative and functional capacity. Several liver-regenerative interventions, most notably portal vein embolization, are used to increase resectability and reduce the risk of PHI. In parallel with the increase in automation and machine assistance to physicians, many semi- and fully automated tools are being developed to facilitate liver volumetry.

CONCLUSION

Liver volumetry is the most reliable tool to detect patients at risk of PHI. Advances in imaging analysis technologies, newly developed functional measures, and liver-regenerative interventions have been improving our ability to perform safe hepatectomy.

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.

Comparing iodized oil with polyvinyl alcohol for portal vein embolization in promoting liver remnant increase before partial hepatectomy

BACKGROUND

To compare the efficacy and safety of iodized oil versus polyvinyl alcohol (PVA) particles in portal vein embolization (PVE) before partial hepatectomy.

METHODS

From October 2016 to December 2021, 86 patients who planned to undergo hepatectomy after PVE were enrolled, including 61 patients post-PVE with PVA particles + coils and 25 patients post-PVE with iodized oil + coils. All patients underwent CT examination before and 2-3 weeks after PVE to evaluate the future liver remnant (FLR). The intercohort comparison included the degree of liver volume growth, changes in laboratory data, and adverse events.

RESULTS

There was no significant difference in the resection rate between the iodized oil group and the PVA particle group (68 % vs. 70 %, p = 0.822). In terms of the degree of hypertrophy (9.52 % ± 13.47 vs. 4.03 % ± 10.55, p = 0.047) and kinetic growth rate (4.07 % ± 5.4 vs. 1.55 % ± 4.63, p = 0.032), the iodized oil group was superior to the PVA group. The PVE operation time in the PVA particle group was shorter than that in the iodized oil group (121. 72 min ± 34.45 vs. 156. 2 min ± 71.58, p = 0.029). There was no significant difference in the degree of hypertrophy between the high bilirubin group and the control group (5.32 % ± 9.21 vs. 6.1 % ± 14.79, p = 0.764). Only 1 patient had a major complication.

CONCLUSIONS

Compared with PVA particles, iodized oil PVE can significantly increase liver volume and the degree of hypertrophy without any significant difference in safety.

Single-Center Retrospective Study Comparing Double Vein Embolization via a Trans-Jugular Approach with Liver Venous Deprivation via a Trans-Hepatic Approach

PURPOSE

To compare safety, technical and clinical outcomes of double vein embolization (DVE) via a trans-jugular approach with liver venous deprivation (LVD) via a trans-hepatic approach.

MATERIALS AND METHODS

A single-center retrospective analysis was conducted on patients undergoing simultaneous portal and hepatic veins embolization in view of a major hepatectomy (June 2019-November 2022). Hepatic vein embolization was performed either by transjugular plug (DVE) or by transhepatic plug followed by glue injection (LVD). Inclusion criteria were availability of pre-procedural CT scan, and availability of CT scans acquired 10 days and 25 days post-procedure. Comparative data included complication rate, fluoroscopy time, dose area product (DAP), Future Liver Remnant volume and function increase (FLR-V and FLR-F increase, respectively) and clinical outcomes.

RESULTS

Thirty-six patients (n = 14 DVE; n = 22 LVD) were included. No baseline significant differences were observed among the two groups. One grade-3 complication (2.8%) was observed in the LVD group; one case of technical failure (2.8%) was observed in the DVE group. Fluoroscopy time and DAP were similar between DVE and LVD (29 ± 17.7 vs. 25 ± 8.2 min, p = 0.97; 105.1 ± 63.5 vs. 143.4 ± 79.5 Gy·cm2, p = 0.15). No differences arose at either time-point in FLR-V increase (46.7 ± 23.1% vs. 48.2 ± 28.2%, 52.9 ± 30.9% vs. 53.2 ± 29%, respectively, p = 0.9). FLR-F increase also did not differ significantly (62.8 ± 55.2 vs. 67.4 ± 57.5, p = 0.9). No differences in drop-out rate from surgery were observed. (28.6% vs. 27.3%, p = 0.93). One case of grade-B post-hepatectomy liver failure (2.8%) was observed in the LVD group.

CONCLUSION

LVD via transhepatic approach and DVE via transjugular approach seem equally safe and effective. Level of Evidence Level 3, Retrospective Cohort Study.

KIAA1429 protects hepatocellular carcinoma cells from ferroptotic cell death with a m6 A-dependent posttranscriptional modification of SLC7A11

N6 -methyladenosine (m6 A) modification represents the most abundant internal methylation of eukaryotic RNAs. KIAA1429 acts as a key component of the m6 A methyltransferase complex, but its function and mechanism in ferroptotic cell death of hepatocellular carcinoma (HCC) are barely defined. We found that KIAA1429 suppression triggered ferroptosis in HCC cells according to increased cell death, iron and MDA levels, C11-BODIPY-positive cells, ROS production and decreased GSH level. Ferroptosis inhibitors ferrostatin-1 (0.5 μM) and liproxstatin-1 (10 μM) blocked KIAA1429 suppression-induced ferroptosis of HCC cells. In addition, overexpressed KIAA1429 notably heightened the activity of cystine/glutamate antiporter (SLC7A11). SLC7A11 up-regulation partially hindered KIAA1429 inhibition-mediated ferroptosis of HCC cells. The regulation SLC7A11 by KIAA1429 was attenuated by global m6 A inhibitor cycloleucine (40 μM). RNA immunoprecipitation confirmed the binding of KIAA1429 to m6 A on SLC7A11 transcript. Additionally, it was proven that KIAA1429 inhibition mitigated HCC growth in subcutaneous xenograft mice through SLC7A11. Altogether, our findings first propose that KIAA1429 protects HCC cells from ferroptosis with a m6 A-dependent post-transcriptional modification of SLC7A11 and offer a novel insight into the dysregulated epi-transcriptomics in the context of HCC.

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.

Liver regeneration after portal vein embolization: comparison between absolute ethanol and N-butyl-cyanoacrylate in an in vivo rat model

PURPOSE

To compare the effects of absolute ethanol (ethanol) and N-butyl-cyanoacrylate (NBCA) on non-embolized liver lobe regeneration in a rat model.

METHODS

Twenty-seven Sprague-Dawley rats underwent portal vein embolization (PVE) using ethanol:lipiodol, 1:1 (ethanol group, n = 11, 40.74%), NBCA:lipiodol, 1:1 (NBCA group, n = 11, 40.74%), or sham treatment (sham group, n = 5, 18.52%). The non-embolized and embolized lobe-to-whole liver weight ratios 14 days after PVE were compared among the groups (n = 5, 18.52%). The expressions of CD68 and Ki-67 and embolized-lobe necrotic area percentages one day after PVE were compared between the ethanol (n = 3, 11.11%) and NBCA (n = 3, 11.11%) groups.

RESULTS

The non-embolized lobe-to-whole liver weight ratio after PVE was significantly higher in the NBCA group (n = 5, 33.33%) than in the ethanol group (n = 5, 33.33%) (84.28% ± 1.53% vs. 76.88% ± 4.12%, P = 0.029). The embolized lobe-to-whole liver weight ratio after PVE was significantly lower in the NBCA group than in the ethanol group (15.72% ± 1.53% vs. 23.12% ± 4.12%, P = 0.029). The proportions of CD68- and Ki-67-positive cells in the non-embolized lobe after PVE were significantly higher in the NBCA group (n = 30, 50%) than in the ethanol group (n = 30, 50%) [60 (48-79) vs. 55 (37-70), P = 0.003; 1 (0-2) vs. 1 (0-2), P = 0.004]. The embolized-lobe necrotic area percentage after PVE was significantly larger in the NBCA group (n = 30, 50%) than in the ethanol group (n = 30, 50%) [29.46 (12.56-83.90%) vs. 16.34 (3.22-32.0%), P < 0.001].

CONCLUSION

PVE with NBCA induced a larger necrotic area in the embolized lobe and promoted greater non-embolized liver lobe regeneration compared with PVE with ethanol.

Percutaneous radiological interventions of the portal vein: a comprehensive review

The portal vein is the largest vessel supplying the liver. A number of radiological interventions are performed through the portal vein, namely for primary pathologies of the portal vein, for inducing liver hypertrophy or to treat the sequelae of portal hypertension among others. The routes used include direct transhepatic, transjugular, and, uncommonly, trans-splenic and through subcutaneous varices. Portal vein embolization and transjugular intrahepatic portosystemic shunt are among the most common portal vein interventions that are performed to induce hypertrophy of the future liver remnant and to treat complications of portal hypertension, respectively. Other interventions include transhepatic obliteration of varices and shunts, portal vein thrombolysis, portal vein recanalization, pancreatic islet cell transplantation, and embolization of portal vein injuries. We present a detailed illustrative review of the various radiological portal vein interventions.

Portal Vein Embolization: Rationale, Techniques, and Outcomes to Maximize Remnant Liver Hypertrophy with a Focus on Contemporary Strategies

Hepatectomy remains the gold standard for curative therapy for patients with limited primary or metastatic hepatic tumors as it offers the best survival rates. In recent years, the indication for partial hepatectomy has evolved away from what will be removed from the patient to the volume and function of the future liver remnant (FLR), i.e., what will remain. With this regard, liver regeneration strategies have become paramount in transforming patients who previously had poor prognoses into ones who, after major hepatic resection with negative margins, have had their risk of post-hepatectomy liver failure minimized. Preoperative portal vein embolization (PVE) via the purposeful occlusion of select portal vein branches to promote contralateral hepatic lobar hypertrophy has become the accepted standard for liver regeneration. Advances in embolic materials, selection of treatment approaches, and PVE with hepatic venous deprivation or concurrent transcatheter arterial embolization/radioembolization are all active areas of research. To date, the optimal combination of embolic material to maximize FLR growth is not yet known. Knowledge of hepatic segmentation and portal venous anatomy is essential before performing PVE. In addition, the indications for PVE, the methods for assessing hepatic lobar hypertrophy, and the possible complications of PVE need to be fully understood before undertaking the procedure. The goal of this article is to discuss the rationale, indications, techniques, and outcomes of PVE before major hepatectomy.

Promoting Surgical Resection through Future Liver Remnant Hypertrophy

An inadequate future liver remnant (FLR) can preclude curative-intent surgical resection for patients with primary or secondary hepatic malignancies. For patients with normal baseline liver function and without risk factors, an FLR of 20% is needed to maintain postsurgical hepatic function. However, the FLR requirement is higher for patients who are exposed to systemic chemotherapy (FLR, >30%) or have cirrhosis (FLR, >40%). Interventional radiologic and surgical methods to achieve FLR hypertrophy are evolving, including portal vein ligation, portal vein embolization, radiation lobectomy, hepatic venous deprivation, and associating liver partition and portal vein ligation for staged hepatectomy. Each technique offers particular advantages and disadvantages. Knowledge of these procedures can help clinicians to choose the suitable technique for each patient. The authors review the techniques used to develop FLR hypertrophy, focusing on technical considerations, outcomes, and the advantages and disadvantages of each approach. Online supplemental material is available for this article. ^©RSNA, 2022.

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.

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: rationale, techniques, outcomes and novel strategies

The incidence of liver cancer has grown in the past decade, with 905,677 new cases and 830,180 deaths in 2020. According to the highest annual fatality ratio, liver cancer is the third-leading cause of cancer-related deaths worldwide. Surgical resection is the mainstay treatment for long-term survival. However, only 25% of patients are surgical candidates. Recent surgical concepts, techniques and multidisciplinary management were developed, including interventional radiology procedures that improve the management algorithm, expand the indications and limit dropouts from curative treatment. This review summarizes up-to-date information on interventional radiology in the management of liver tumors.

Endovascular Use of Cyanoacrylate-Lipiodol Mixture for Peripheral Embolization: Properties, Techniques, Pitfalls, and Applications

Endovascular embolization agents are particles and fluids that can be released into the bloodstream through a catheter to mechanically and/or biologically occlude a target vessel, either temporarily or permanently. Vascular embolization agents are available as solids, liquids, and suspensions. Although liquid adhesives (glues) have been used as embolic agents for decades, experience with them for peripheral applications is generally limited. Cyanoacrylates are the main liquid adhesives used for endovascular interventions and have a major role in managing vascular abnormalities, bleeding, and many vascular diseases. They can only be injected as a mixture with ethiodized oil, which provides radiopacity and modulates the polymerization rate. This review describes the characteristics, properties, mechanisms of action, modalities of use, and indications of the cyanoacrylate-Lipiodol® combination for peripheral embolization.