Portal Vein Embolization: History and Current Indications

Advancements in Interventional Radiology for Managing Hepatic Encephalopathy: A Comprehensive Review

Hepatic encephalopathy (HE) is a complex neuropsychiatric syndrome resulting from liver dysfunction, leading to cognitive, behavioral, and motor impairments. The management of HE has traditionally relied on pharmacological treatments, dietary modifications, and liver transplantation. However, recent advancements in interventional radiology (IR) have introduced minimally invasive procedures that offer promising alternatives. This comprehensive review explores the latest IR techniques, including transjugular intrahepatic portosystemic shunt (TIPS), balloon-occluded retrograde transvenous obliteration (BRTO), portal vein embolization (PVE), and Yttrium-90 (Y90) radioembolization. The efficacy, clinical outcomes, and potential complications of these techniques are examined through an analysis of current studies and trials. The review highlights the benefits of IR in reducing portal hypertension and improving hepatic blood flow, ultimately alleviating HE symptoms. Additionally, it underscores the importance of multidisciplinary collaboration, ongoing research, and the development of clear patient selection criteria to optimize the use of IR in HE management. By integrating these advancements into clinical practice, healthcare providers can enhance the quality of care and improve outcomes for patients with HE.

Case report: Portal vein ligation: lessons from patients with PRETEXT III hepatoblastoma in restoring future liver remnant before major hepatectomy and literature review

Background

We describe three cases involving three patients with PRETEXT III hepatoblastoma invading the hepatic hilum. After portal vein embolization, the patients underwent uncomplicated trisectionectomy.

Methods

Medical records between March 2016 and March 2021 were reviewed, and three patients were selected. A literature review of techniques for increasing future liver remnant in children diagnosed with hepatoblastoma was also conducted.

Results

All tumors involved the right lobe and hepatic hilum (PRETEXT III). After neoadjuvant chemotherapy, the tumor size decreased, but hilar involvement was unimproved. Right portal vein ligation (RPVL) was performed to increase the left lobe volume. Post-ligation, the remnant liver increased. Liver function was restored to normal levels within 5 days after the hepatectomy. All patients underwent two cycles of adjuvant chemotherapy without tumor recurrence.

Conclusions

RPVL can be safely performed before extended hepatic resection in children with a giant hepatoblastoma invading the hepatic hilum. The tumor was completely resected by securing a sufficient margin and increasing the residual liver volume with portal vein embolization. The patients recovered and underwent adjuvant chemotherapy without the deterioration of liver function.

Efficacy and safety of different options for liver regeneration of future liver remnant in patients with liver malignancies: a systematic review and network meta-analysis

BACKGROUND

Several treatments induce liver hypertrophy for patients with liver malignancies but insufficient future liver remnant (FLR). Herein, the aim of this study is to compare the efficacy and safety of existing surgical techniques using network meta-analysis (NMA).

METHODS

We searched PubMed, Web of Science, and Cochrane Library from databases for abstracts and full-text articles published from database inception through Feb 2022. The primary outcome was the efficacy of different procedures, including standardized FLR (sFLR) increase, time to hepatectomy, resection rate, and R0 resection margin. The secondary outcome was the safety of different treatments, including the rate of Clavien-Dindo≥3a and 90-day mortality.

RESULTS

Twenty-seven studies, including three randomized controlled trials (RCTs), three prospective trials (PTs), and twenty-one retrospective trials (RTs), and a total number of 2075 patients were recruited in this study. NMA demonstrated that the Associating Liver Partition and Portal vein ligation for Staged hepatectomy (ALPPS) had much higher sFLR increase when compared to portal vein embolization (PVE) (55.25%, 95% CI 45.27-65.24%), or liver venous deprivation(LVD) (43.26%, 95% CI 22.05-64.47%), or two-stage hepatectomy (TSH) (30.53%, 95% CI 16.84-44.21%), or portal vein ligation (PVL) (58.42%, 95% CI 37.62-79.23%). ALPPS showed significantly shorter time to hepatectomy when compared to PVE (-32.79d, 95% CI -42.92-22.66), or LVD (-34.02d, 95% CI -47.85-20.20), or TSH (-22.85d, 95% CI -30.97-14.72), or PVL (-43.37d, 95% CI -64.11-22.62); ALPPS was considered as the highest resection rate when compared to TSH (OR=6.09; 95% CI 2.76-13.41), or PVL (OR =3.52; 95% CI 1.16-10.72), or PVE (OR =4.12; 95% CI 2.19-7.77). ALPPS had comparable resection rate with LVD (OR =2.20; 95% CI 0.83-5.86). There was no significant difference between them when considering the R0 marge rate. ALPPS had a higher Clavien-Dindo≥3a complication rate and 90-day mortality compared to other treatments, although there were no significant differences between different procedures.

CONCLUSIONS

ALPPS demonstrated a higher regeneration rate, shorter time to hepatectomy, and higher resection rate than PVL, PVE, or TSH. There was no significant difference between them when considering the R0 marge rate. However, ALPPS developed the trend of higher Clavien-Dindo≥3a complication rate and 90-day mortality compared to other treatments.

Comparison of Liver Fibrosis and Function Indices with Extracellular Volume using Dual-Energy CT: A Retrospective Study

BACKGROUND

Dual-energy computed tomography (DECT) enables the direct measurement of iodine accumulation in the extracellular space.

OBJECTIVE

To compare measures of liver fibrosis and function with extracellular volume (ECV) from iodine/water images using DECT.

METHODS

Data was obtained from 119 consecutive patients who underwent abdominal DECT. A region of interest was set in the right lobe of the liver, pancreas, spleen, and aorta on iodine density images. ECV was calculated using the following formula: ECV = (1  hematocrit) × [iodine concentration in the liver (or pancreas, spleen) / iodine concentration in the aorta]. The severity of liver fibrosis was estimated using the aminotransferase/platelet ratio index (APRI) and the Fibrosis-4 (FIB-4) index. Liver function was assessed by the Child-Pugh classification and albumin-bilirubin (ALBI) grade. Data were analyzed by Spearman rank correlation coefficient, one-way analysis of variance, and post hoc analysis.

RESULTS

The correlation between ECV and fibrosis indices (APRI and FIB-4) was only significant and with a weak magnitude for the liver ECV quantification at the equilibrium phase (r=0.25 and r=0.20, respectively). The correlations between liver function index and ECV quantification were more robust than with fibrosis index. The highest correlations (r=0.50) were found between ALBI grade and liver ECV at the equilibrium phase. Liver ECV value at the equilibrium phase were significant difference between ALBI grade 1 vs. 2 and grade 1 vs. 3.

CONCLUSION

Liver ECV quantification by DECT is more suitable for evaluating liver function than liver fibrosis severity.

Current strategies to induce liver remnant hypertrophy before major liver resection

Hepatic resection is the gold standard for patients affected by primary or metastatic liver tumors but is hampered by the risk of post-hepatectomy liver failure. Despite recent improvements, liver surgery still requires excellent clinical judgement in selecting patients for surgery and, above all, efficient pre-operative strategies to provide adequate future liver remnant. The aim of this article is to review the literature on the rational, the preliminary assessment, the advantages as well as the limits of each existing technique for preparing the liver for major hepatectomy.

Oncological benefits of portal vein embolization for patients with hepatocellular carcinoma

Portal vein embolization (PVE) for hepatocellular carcinoma (HCC) was first introduced in 1986 and has been continuously developed throughout the years. Basically, PVE has been applied to expand the indication of liver resection for HCC patients of insufficient future liver remnant. Importantly, PVE can result in tumor progression in both embolized and non-embolized livers; however, long-term survival after liver resection following PVE is at least not inferior compared with liver resection alone despite the smaller future liver remnant volume. Five-year disease-free survival and 5-year overall survival were 17% to 49% and 12% to 53% in non-PVE patients, and 21% to 78% and 44% to 72% in PVE patients, respectively. At present, it has proven that PVE has multiple oncological advantages for both surgical and nonsurgical treatments. PVE can also enhance the anticancer effects of transarterial chemoembolization and can avoid intraportal tumor cell dissemination. Additional interventional transarterial chemoembolization and hepatic vein embolization as well as surgical two-stage hepatectomy and associated liver partition and portal vein ligation for staged hepatectomy can enhance the oncological benefit of PVE monotherapy. Taken together, PVE is an important treatment which we recommend for listing in the guidelines for HCC treatment strategies.

Evaluation of Liver Function and the Role of Biliary Drainage before Major Hepatic Resections

Background

Prevention of posthepatectomy liver failure is a prerequisite for improving the postoperative outcome of perihilar cholangiocarcinoma. From this perspective, appropriate assessment of future liver remnant (FLR) function and the optimized preparation are mandatory.

Summary

FLR volume ratio using CT volumetry based on 3-dimensional vascular imaging is the current assessment yardstick and is sufficient for assessing a normal liver. However, in a liver with underling parenchymal disease such as fibrosis or prolonged jaundice, weighing up the degree of liver damage against the FLR volume ratio is necessary to know the real FLR function. For this purpose, the indocyanine green (ICG) clearance test, monoethylglycinexylidide (MEGX) test, liver maximum capacity (LiMAX) test, ^99mTc-labeled galactosyl human serum albumin (^99mTc-GSA) scintigraphy, albumin-bilirubin (ALBI) grade, and ALPlat (albumin × platelets) criterion are used. After the optimization of FLR function by means of portal vein embolization or associating liver partition and PVL (portal vein ligation) for staged hepatectomy (ALPPS), SPECT scintigraphy with either ^99mTc-GSA or ^99mTc-mebrofenin compensates for misestimation due to the regional heterogeneity of liver function. The role of preoperative biliary drainage has long been debated, with the associated complications having led to a lack of approval. However, the recent establishment of safety and an improvement in success rates of endoscopic biliary drainage seem to be changing the awareness of the importance of biliary drainage.

Key Messages

Appropriate selection of an assessment method is of prime importance to predict the FLR function according to the preoperative condition of the liver. Preoperative biliary drainage in patients with perihilar cholangiocarcinoma is gaining support due to the increasing safety and success rate, especially in patients who need optimization of their liver function before hepatectomy.

Short-Term Outcomes of Patients Undergoing Portal Vein Embolization: an ACS-NSQIP Procedure-Targeted Hepatectomy Analysis

BACKGROUND

Preoperative portal vein embolization (PVE) is utilized to induce growth of the future liver remnant volume (FLRV) among patients at elevated risk of post-hepatectomy liver failure (PHLF).

METHODS

The American College of Surgery National Surgical Quality Improvement Program (ACS-NSQIP) database was used to compare short-term outcomes of PVE versus non-PVE patients. A propensity score match (PSM) was used to compare short-term outcomes among PVE and non-PVE patients.

RESULTS

Among the 11,243 patients included in the study, 462 (4.1%) patients had a PVE. Postoperatively, patients who underwent PVE had a higher incidence of overall (PVE, 44% vs. non-PVE, 23%) and liver-specific complications (biliary leak PVE, 16% vs. non-PVE, 7%; post-hepatectomy liver failure [PHLF] PVE, 17% vs. non-PVE, 5%), as well as a longer length of stay (> 7 days PVE, 39% vs. non-PVE, 22%) compared with the non-PVE group (all p < 0.001). After PSM, no differences in mortality or LOS were observed among PVE and non-PVE patients. PVE patients remained more likely to have a bile leak, organ/surgical-site infection, and PHLF versus non-PVE patients (all p < 0.05).

CONCLUSION

Among patients who underwent PVE before hepatectomy, the risk of postoperative complications was 1.6-fold higher than non-PVE patients. After PSM, PVE patients still had an increased risk of complications.

Transcatheter embolization with Squid, combined with other embolic agents or alone, in different abdominal diseases: a single-center experience in 30 patients

Background

Squid, as Onyx, is an ethylene-vinyl alcohol copolymer (EVOH)-based liquid embolic agent developed for neuroradiologic interventions with poor application in abdominal district. Our aim was to evaluate safety, complications, and efficacy of transcatheter embolization using the two available formulations Squid-18 and 12, in 30 patients affected by different abdominal diseases.

Results

Transcatheter embolization with Squid, combined with other embolic agents, as poly vinyl alcohol (PVA) particles, coils and amplatzer plugs, or alone (type 2 endoleak), was performed in 30 patients, as follows: 10 portal vein embolizations (PVEs), 6 arteriovenous malformations (AVMs), 5 visceral artery aneurysms (VAAs), 4 type 2 endoleaks, 3 preoperative embolizations, 1 acute arterial bleeding, 1 female varicocele. Squid was always administered using dimethyl sulfoxide (DMSO) compatible microcatheters. Technical success, 30-day clinical success and complications were assessed.

Technical success was 90%. 3 patients (2 AVMs, 1 VAA) required re-intervention successfully performed in all cases. Major complications, cases of microcatheter entrapment and DMSO-related poor pain control were not recorded. 30-day clinical success was 93.3%: in 2 patients submitted to PVE a sufficient future liver remnant (FLR) hypertrophy was not achieved.

Conclusion

Squid was successfully used with low complication rate in many abdominal diseases showing a valid embolic action either combined with other embolic agents or alone in type 2 endoleak. The availability of different formulations (Squid-18 and Squid-12) variable for viscosity makes Squid preferable to Onyx as EVOH-based liquid embolic agent, even though comparable studies in different abdominal districts with a larger cohort of patients will be necessary.