Percutaneous ipsilateral portal vein embolization using a modified four-lumen balloon catheter with fibrin glue: initial clinical experience

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.

Fibrin Glue in Interventional Radiology: How to Use It

A fibrin glue kit consists of separate solutions of fibrinogen and thrombin that instantly coagulate when mixed together and can be used as an embolic agent and tissue adhesive in several interventional procedures, such as the closure of enterocutaneous, postoperative pancreatic, and bronchopulmonary fistulas, embosclerosis of biloma, and portal vein embolization. Separate and simultaneous injections of fibrinogen and thrombin solutions at the target site are necessary; therefore, insertion of two catheters or a balloon catheter with multiple lumen is required. The combined use of metallic coils is also effective for a large fistula as the coils can provide a matrix for retaining the fibrin glue, in addition to partially occluding the fistulous tract. Mixing contrast medium or iodized oil with a thrombin solution is also key to achieving radiopacity.

Portal Vein Embolization as an Oncosurgical Strategy Prior to Major Hepatic Resection: Anatomic, Surgical, and Technical Considerations

Preoperative portal vein embolization (PVE) is used to extend the indications for major hepatic resection, and it has become the standard of care for selected patients with hepatic malignancies treated at major hepatobiliary centers. To date, various techniques with different embolic materials have been used with similar results in the degree of liver hypertrophy. Regardless of the specific strategy used, both surgeons and interventional radiologists must be familiar with each other's techniques to be able to create the optimal plan for each individual patient. Knowledge of the segmental anatomy of the liver is paramount to fully understand the liver segments that need to be embolized and resected. Understanding the portal vein anatomy and the branching variations, along with the techniques used to transect the portal vein during hepatic resection, is important because these variables can affect the PVE procedure and the eventual surgical resection. Comprehension of the advantages and disadvantages of approaches to the portal venous system and the various embolic materials used for PVE is essential to best tailor the procedures for each patient and to avoid complications. Before PVE, meticulous assessment of the portal vein branching anatomy is performed with cross-sectional imaging, and embolization strategies are developed based on the patient's anatomy. The PVE procedure consists of several technical steps, and knowledge of these technical tips, potential complications, and how to avoid the complications in each step is of great importance for safe and successful PVE and ultimately successful hepatectomy. Because PVE is used as an adjunct to planned hepatic resection, priority must always be placed on safety, without compromising the integrity of the future liver remnant, and close collaboration between interventional radiologists and hepatobiliary surgeons is essential to achieve successful outcomes.

Strategies to increase the resectability of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is best treated by liver transplantation, but the applicability of transplantation is greatly limited. Tumor resection in partial hepatectomy is hence resorted to. However, in most parts of the world, only 20%-30% of HCCs are resectable. The main reason for such a low resectability is a future liver remnant too small to be sufficient for the patient. To allow more HCC patients to undergo curative hepatectomy, a variety of ways have been developed to increase the resectability of HCC, mainly ways to increase the future liver remnants in patients through hypertrophy. They include portal vein embolization, sequential transarterial chemoembolization and portal vein embolization, staged hepatectomy, two-staged hepatectomy with portal vein ligation, and Associating Liver Partition and Portal Vein Ligation in Staged Hepatectomy. Herein we review, describe and evaluate these different ways, ways that can be life-saving.

Prediction of portal pressure from intraoperative ultrasonography

BACKGROUND

Portal hypertension is a major risk factor for hepatic failure or bleeding in patients who have undergone hepatectomy, but it cannot be measured indirectly. We attempted to evaluate the intraoperative ultrasonography parameters that correlate with portal pressure (PP) in patients undergoing hepatectomy.

METHODS

We examined 30 patients in whom PP was directly measured during surgery. The background liver conditions included chronic viral liver disease in seven patients, chemotherapy-associated steatohepatitis in four patients, fatty liver in one patient, hepatolithiasis in one patient, obstructive jaundice in one patient, and a normal liver in 16 patients. A multivariate logistic analysis and linear regression analysis were conducted to develop a predictive formula for PP.

RESULTS

The mean PP was 10.4 ± 4.1 mm Hg. The PP tended to be increased in patients with chronic viral hepatitis. A univariate analysis identified the association of the six following parameters with PP: the platelet count and the maximum (max), minimum (min), endo-diastolic, peak-systolic, and mean velocity in the portal vein (PV) flow. Using multiple linear regression analysis, the predictive formula using the PV max and min was as follows: Y (estimated PP) = 18.235-0.120 × (PV max.[m/s])-0.364 × (PV min). The calculated PP (10.44 ± 2.61 mm Hg) was nearly the same as the actual PP (10.43 ± 4.07 mm Hg). However, there was no significant relationship between the calculated PP and the intraoperative blood loss and post hepatectomy morbidity.

CONCLUSIONS

This formula, which uses ultrasonographic Doppler flow parameters, appears to be useful for predicting PP.

Comprehensive Predictors of Portal Pressure from Functional Liver Reserve in Patients Who Underwent Hepatectomy

Portal hypertension is a major risk factor for hepatic failure or intestinal bleeding in patients with liver disease but cannot be measured indirectly. We attempted to comprehensively evaluate preoperative parameters of functional liver reserve that correlated with portal pressure (PP) in patients with various liver diseases. We examined 93 patients in whom portal pressure was directly measured during preoperative portal vein embolization (PVE) or operation. Background liver included chronic viral liver disease in 43 patients, obstructive jaundice in 29 patients, and normal liver in 21. Multivariate logistic analysis and linear regression analysis were applied to create a predictive formula for PP. Mean PP was 13.4 ± 4.9 cm H2O, and PP was significantly associated with severity of liver injury, hepatic fibrosis, intraoperative blood loss, and post-hepatectomy morbidity (p < 0.05 each). Mean PP after PVE (22.5 ± 7.8 cm H2O) was significantly increased compared to that before embolization (13.1 ± 4.7 cm H2O; p < 0.01). Univariate analysis identified seven significant parameters of preoperative liver function associated with PP: indocyanine green (ICG) test result, liver uptake and clearance index (HH15) on (99m)Tc-galactosyl serum albumin liver scintigraphy, total bilirubin level, prothrombin activity, and hyaluronate level. Using multiple linear regression analysis, the predictive formula using ICG and HH15 was as follows: Y (estimated PP) = 0.273 + 0.086 × ICGR15 + 0.193 × HH15. The calculated PP (11.5 ± 4.6 cm H2O (-1.9 cm H2O)) was lower than true PP, which was significantly associated with post-hepatectomy morbidity (p < 0.05). The correlation between true and calculated PP was weak, and prediction using the conventional liver functional parameters was limited at present and, however, estimating PP appears to be useful in evaluating portal hypertension and post-hepatectomy morbidity.

Tzeng CW, Vauthey JN. Portal vein embolization for hepatocellular carcinoma

Portal vein embolization (PVE) improves the safety of major hepatectomy through hypertrophy of the future liver remnant (FLR), atrophy of the liver volume to be resected, and improvement in patient selection. Because most patients with hepatocellular carcinoma (HCC) have liver parenchymal injury due to underlying viral hepatitis or alcoholic liver fibrosis/cirrhosis, indication of PVE is relatively complex and sequential procedures, including transarterial chemoembolization, are required to maximize the effect of PVE as well as to minimize tumor progression due to increased arterial flow after PVE. PVE is currently indicated for patients with relatively well-preserved hepatic function [Child-Pugh A and indocyanine green tolerance test (ICG-R15) <20%) to achieve minimal FLR volume for safe major hepatectomy. FLR volume >40% is the minimal requirement for patients with chronic hepatitis or cirrhosis, and further strict criteria (FLR volume >50%) have been recommended for patients with marginal liver functional reserve (ICG-R15, 10-20%). Recent clinical results have suggested that PVE can be safely performed in patients with HCC and that it contributes to improved survival after major hepatectomy.

Portal vein embolization using a Histoacryl/Lipiodol mixture before right liver resection

PURPOSE

The purpose of this retrospective study was to evaluate the efficacy and safety of percutaneous transhepatic portal vein embolization (PVE) of the right liver lobe using Histoacryl/Lipiodol mixture to induce contralateral liver hypertrophy before right-sided (or extended right-sided) hepatectomy in patients with primarily unresectable liver tumors.

METHODS

Twenty-one patients (9 females and 12 males) underwent PVE due to an insufficient future liver remnant; 17 showed liver metastases and 4 suffered from biliary cancer. Imaging was performed prior to and 4 weeks after PVE. Surgery was scheduled for 1 week after a CT or MRI control. The primary study end point was technical success, defined as complete angiographical occlusion of the portal vein. The secondary study end point was evaluation of liver hypertrophy by CT and MRI volumetry and transfer to operability.

RESULTS

In all the patients, PVE could be performed with a Histoacryl/Lipiodol mixture (n = 20) or a Histoacryl/Lipiodol mixture with microcoils (n = 1). No procedure-related complications occurred. The volume of the left liver lobe increased significantly (p < 0.0001) by 28% from a mean of 549 ml to 709 ml. Eighteen of twenty-one patients (85.7%) could be transferred to surgery, and the intended resection could be performed as planned in 13/18 (72.3%) patients.

CONCLUSION

Preoperative right-sided PVE using a Histoacryl/Lipiodol mixture is a safe technique and achieves a sufficient hypertrophy of the future liver remnant in the left liver lobe.

Percutaneous transhepatic portal vein embolization: rationale, technique, and outcomes

Portal vein embolization (PVE) is used to induce preoperative liver hypertrophy in patients with anticipated marginal future liver remnant (FLR) volumes who are otherwise potential candidates for resection. PVE can be performed utilizing the transhepatic contralateral and ipsilateral approaches. The transhepatic contralateral approach is the most commonly used technique worldwide, largely owing to its technical ease. However, the contralateral approach risks injuring the FLR, thereby compromising the planned surgical resection. The transhepatic ipsilateral approach offers a potentially safer alternative because the complications associated with this approach affect only the hepatic lobe that will be resected and are usually not serious enough to preclude surgery. This article discusses PVE using the transhepatic ipsilateral and contralateral approaches, including patient selection criteria, anatomical and technical considerations, and patient complications and outcomes.

Foam sclerotherapy using polidocanol (aethoxysklerol) for preoperative portal vein embolization in 16 patients

PURPOSE

To evaluate the clinical safety and effectiveness of foam sclerotherapy using polidocanol for preoperative portal vein embolization (PVE) before hemihepatectomy of the liver.

MATERIALS AND METHODS

From March 2006 to October 2008, foam sclerotherapy using polidocanol was performed in 16 patients (male-to-female ratio of 12:4, age range 48-75 years [mean 62]) for PVE. Patients were diagnosed with Klatskin tumor (n = 13), gallbladder (GB) cancer (n = 2), or hepatocellular carcinoma (HCC) (n = 1). The foam was composed of a 1:2:1 ratio of 3% polidocanol (Aethoxysklerol; Kreussler Pharma, Wiesbaden, Germany), room air, and contrast media (Xenetix 350; Guerbet, Aulnay-Sous-Bois, France). The total amount of polidocanol used (2 to 8 mL [mean 4.6]) varied according to the volume of the target portal vein. We calculated the volume of future liver remnant (FLR) before and after PVE and evaluated complications associated with the use of polidocanol foam sclerotherapy for PVE.

RESULTS

Technical success was achieved in all patients. All patients were comfortable throughout the procedure and did not experience pain during sclerotherapy. No periprocedural morbidity or mortality occurred. Patients underwent a liver dynamic computed tomography (CT) scan 2-4 weeks after PVE. FLR increased significantly after PVE using polidocanol foam from 19.3% (range 16-35%) before PVE to 27.8% (range 23-42%) after PVE (p = 0.001). All patients were operable for hemihepatectomy of the liver and achieved effective resection.

CONCLUSION

Foam sclerotherapy using polidocanol is clinically safe and effective for preoperative PVE.

Portal vein embolization: rationale, outcomes, controversies and future directions

Portal vein embolization (PVE) is now considered the standard of care to improve safety for patients undergoing extensive hepatectomy with an anticipated small future liver remnant (FLR). PVE is used to induce contralateral liver hypertrophy in preparation for major liver resection. Optimal patient selection is essential to maximize the clinical benefits of PVE. Computed tomography volumetry is used to calculate a standardized FLR and determine the need for preoperative PVE. Percutaneous PVE can be performed via the transhepatic ipsilateral or contralateral approaches, depending on operator preference. Several different embolic agents are available to the interventional radiologist, all with similar effectiveness in inducing hypertrophy. When an extended hepatectomy is planned, right PVE should include segment 4, in order to maximize FLR hypertrophy. Multiple studies have demonstrated the beneficial outcomes of PVE in both patients with healthy livers and with underlying liver diseases. Novel improvements to PVE should expand its scope to patients who were previously not candidates for the procedure.

Present status and future perspectives of preoperative portal vein embolization

BACKGROUND

Portal vein embolization (PVE) has been gaining increasing acceptance before major hepatectomy. This review presents the application, outcome, and recent developments of PVE.

METHODS

After a systematic search of "portal vein embolization" in PubMed, we reviewed and retrieved articles written in English related to PVE. There were no other criteria for exclusion of published information pertaining to this topic.

RESULTS

Hypertrophy of future liver remnants with PVE in patients with hepatobiliary malignancy results in fewer complications and shorter hospital stays after major hepatectomy, and add to the pool of candidates for surgical treatment. Some new techniques, such as sequential hepatic artery-portal vein embolization and PVE with stem cell administration, have showed a promising clinical future.

CONCLUSIONS

PVE has achieved significant improvement in the outcome of major hepatectomy, and has enlarged the candidate pool of liver resection as well. Future study is needed to identify the precise mechanism of liver regeneration after PVE.

Preoperative portal vein embolization: indications and technical considerations

Preoperative portal vein embolization (PVE) has become an important tool in the management of select patients before major hepatic resection. PVE redirects portal flow to the intended future remnant liver (FRL) to induce hypertrophy of the nondiseased portion of the liver and thereby may reduce complications and shorten hospital stays after surgery. This article reviews the technical considerations for performing PVE including the use of the ipsilateral or contralateral approaches, how to choose a particular embolic agent for PVE, the importance of liver volumetric measurements to estimate functional hepatic reserve, the pathophysiology of PVE, and some of the results showing the benefit of the procedure. In addition, the indications and contraindications for performing PVE in patients with and without chronic liver disease, the use of combination therapies, and the concern for tumor growth after PVE will be discussed.