Preoperative biliary drainage of the hepatic lobe to be resected does not affect liver hypertrophy after percutaneous transhepatic portal vein embolization

Hyperbilirubinemia does not impair induced liver hypertrophy after portal vein Embolization-a retrospective scandinavian cohort study

BACKGROUND

Portal vein embolization (PVE) may be used to induce hypertrophy of the future liver remnant (FLR) before major hepatectomy. The influence of hyperbilirubinemia on FLR hypertrophy after PVE is controversial. The aim of this study was to compare FLR hypertrophy after PVE between patients with and without elevated P-bilirubin.

MATERIALS/METHODS

This is a Scandinavian retrospective cohort study of patients from five hepatobiliary centres. This study included patients who underwent right-sided PVE from 2013 to 2023. Data were collected from electronic medical records. FLR growth was analysed with respect to normal or elevated P-bilirubin.

RESULTS

In total, 410 patients were included in this study. Among the total cohort, 105 patients had elevated P-bilirubin levels (≥26 μmol/L) at the time of PVE. Elevated P-bilirubin levels were not associated with impaired FLR hypertrophy after PVE, as determined by absolute growth (p < 0.001), relative growth (p = 0.008), degree of hypertrophy (p < 0.001) and kinetic growth rate (p = 0.002). Multivariable analysis revealed that elevated P-bilirubin levels at the time of PVE (p = 0.002) together with the use of N-butyl cyanoacrylate (NBCA) as an embolizing material (p = 0.009) were associated with increased FLR hypertrophy. A larger estimated total liver volume was associated with reduced FLR hypertrophy (p < 0.001).

CONCLUSION

In this multicentre, retrospective cohort study, we were unable to show any negative effect of elevated P-bilirubin on FLR hypertrophy at the time of PVE. There is no need for P-bilirubin levels to normalize before PVE. This study supports the ongoing shift towards NBCA as an embolizing material.

The Interplay Between Biliary Occlusion and Liver Regeneration: Repeated Regeneration Stimuli Restore Biliary Drainage by Promoting Hepatobiliary Remodeling in a Rat Model

Background and Aims

Patients with malignant biliary obstruction do not seem to benefit from “two-stage hepatectomy” due to an impairment of liver regeneration. We designed a novel model of “repeated regeneration stimuli” in rats mimicking a “two-stage hepatectomy” with selective or complete biliary occlusion mimicking Klatskin tumors III° or IV°. Using this new model, we wanted to investigate (1) the impact of preexistent cholestasis of different extent on the time course of liver regeneration and (2) the dynamics of hepatobiliary remodeling under regeneration conditions.

Materials and Methods

Rats were subjected to a sequence of three operations: surgical induction of biliary occlusion, followed by “repeated regeneration stimuli” consisting of ligation of the left branch of the portal vein (supplying 70% of the liver volume, sPVL) as first stage and a 70%-hepatectomy (70%PHx) as second stage. Biliary occlusion (1st procedure) was induced by ligating and transection of either the common (100%, tBDT) or the left bile duct (70%, sBDT). A sham operation without ligating the bile duct was performed as control (0%, Sham). Two weeks later, on day 14 (POD14), the sPVL (2nd procedure) was performed. Another week later (POD 21), the 70%PHx (3rd procedure) took place and animals were observed for 1 week (POD 28). The first experiment (n = 45 rats) was dedicated to investigating liver regeneration (hypertrophy/atrophy), proliferative activity and hepatobiliary histomorphology (2D-histology: HE, BrdU) in the future liver remnant (FLR). The second experiment (n = 25 rats) was performed to study the dynamics of hepatobiliary remodeling in livers with different regenerative pressure (tBDT only POD21 vs. tBDT only POD 28 vs. tBDT + sPVL vs. tBDT + 70%PHx vs. tBDT + sPVL + 70%PHx) using μCT scans of explanted livers.

Results

Effect of biliary occlusion

Total biliary occlusion (tBDT) led to a 2.4-fold increase in whole liver volume due to severe biliary proliferation within 14 days. In contrast, partial biliary occlusion (sBDT) caused only a volume gain of the obstructed liver lobes due to biliary proliferates, resulting in a minor increase of total liver volume (1.7-fold) without an increase in bilirubin levels.

Liver regeneration and atrophy

As expected, sPVL caused substantial volume gain (tBDT: 3-fold; sBDT: 2.8-fold; Sham 2.8-fold) of FLR and a substantial volume loss (tBDT: 0.9-fold; sBDT: 0.6-fold; Sham: 0.4-fold) of the portally deprived “future resected lobes” compared to the preoperative liver volume. The subsequent 70%PHx promoted a further volume gain of the FLR in all groups (tBDT: 4-fold; sBDT: 3-fold; Sham 3-fold compared to original volume) until POD 28. Hepatobiliary remodeling: After tBDT, we identified histologically three phases of hepatobiliary remodeling in the FLR. Following tBDT, biliary proliferates developed, replacing about 15% of the hepatocellular tissue. After sPVL we found incomplete restoration of the hepatocellular tissue with a visible reduction of the biliary proliferates. The 70%PHx led to an almost complete recovery of the hepatocellular tissue in the FLR with a nearly normal liver architecture. In contrast, after sBDT and Sham we observed a near normal liver morphology in the FLR at all time points. CT-scanning of the explanted livers and subsequent 3D reconstruction visualized the development of extrahepatic biliary collaterals. Collaterals were detected in 0/5 cases 1 week after sPVL (first regeneration stimulus), and in even more cases (3/5) 1 week after the 70%PHx (second regeneration stimulus). Histological workup identified the typical biliary cuboid epithelium as inner lining of the collaterals and peribiliary glands.

Conclusion

Liver volume of the FLR increased in cholestatic rats mainly due to biliary proliferates. Application of repeated regeneration stimuli in the style of a “two-stage hepatectomy” promoted almost full restoration of hepatocellular tissue and architecture in the FLR by reestablishing biliary drainage via formation of biliary collaterals. Further exploration of the dynamics in hepatobiliary modeling using this model might help to better understand the underlying mechanism.

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.

To Systematically Evaluate and Analyze the Efficacy and Safety of Transcatheter Arterial Chemoembolization (TACE) in the Treatment of Primary Liver Cancer

The efficacy and safety of transcatheter arterial chemoembolization (TACE) are systematically evaluated in the treatment of primary liver cancer, which provides a reference for clinical practice and more in-depth research. Cochrane Library, PubMed, EMbase, CBM, CNKI, VIP, and WanFang Data, supplemented by other searches, collected all randomized controlled trials (RCT) comparing TACE combined with TACE alone for HCC. The meta-analysis, after selecting the literature, extracting data, and evaluating the methodological quality of the included studies following the inclusion criteria, was performed using RevMan 5.1 software. There was statistical difference in 3-year survival rate of TACE combined with heat treatment for advanced hepatocellular carcinoma (OR = 1.72,95%CI (1.22,2.41), P=0.002, I2 = 0%, and Z = 3.12), total effective rate (OR = 1.91,95%CI (1.31,2.78), P=0.0008, I2 = 0%, and Z = 3.37), quality-of-life improvement rate (OR = 2.29,95%CI (1.62,3.23), P < 0.00001, I2 = 83%, and Z = 3.37), and complication rate (OR = 2.29,95%CI (1.62,3.23), P < 0.00001, I2 = 83%, and Z = 3.37). Compared with TACE alone, TACE combined with hyperthermia can significantly improve the survival rate and recent efficacy of patients, improve the quality of life, and have a trend to reduce the incidence of toxicity. However, its long-term efficacy and more comprehensive safety need to be verified by more sample and high-quality RCT.

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

This systematic review was conducted to determine factors that are associated with the degree of hypertrophy of the future liver remnant following portal vein embolization. An extensive search on September 15, 2020, and subsequent literature screening resulted in the inclusion of forty-eight articles with 3368 patients in qualitative analysis, of which 18 studies were included in quantitative synthesis. Meta-analyses based on a limited number of studies showed an increase in hypertrophy response when additional embolization of segment 4 was performed (pooled difference of medians = − 3.47, 95% CI − 5.51 to − 1.43) and the use of N-butyl cyanoacrylate for portal vein embolization induced more hypertrophy than polyvinyl alcohol (pooled standardized mean difference (SMD) = 0.60, 95% CI 0.30 to 0.91). There was no indication of a difference in degree of hypertrophy between patients who received neo-adjuvant chemotherapy and those who did not receive pre-procedural systemic therapy

(pooled SMD = − 0.37, 95% CI − 1.35 to 0.61), or between male and female patients (pooled SMD = 0.19, 95% CI − 0.12 to 0.50).

The study was registered in the International Prospective Register of Systematic Reviews on April 28, 2020 (CRD42020175708).