Use Of Portal Vein Embolization Research Articles

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.

Extended Right-hemihepatectomy Is Preferred for Perihilar Cholangiocarcinoma.

Extended Right-hemihepatectomy Is Preferred for Perihilar Cholangiocarcinoma.

4:12 PM Abstract No. 245 Safety and efficacy of sequential Y90 radioembolization and portal vein embolization in patients with hepatocellular carcinoma and metastatic colorectal cancer

The use of portal vein embolization is widely applied to induce hypertrophy of the future liver remnant in preoperative patients. Patients may not receive surgery for various reasons. The safety and efficacy of combined radioembolization and portal vein embolization is not understood. We present our experience of sequential Y90 RE and portal vein embolization. A retrospective review of patients treated with a combination of portal vein embolization and Y90 radioembolization between January 2008 and August 2019 was cataloged. Post procedure laboratory values, clinical notes, cross sectional imaging and adverse events were recorded. 14 patients (10 mCRC, 4 HCC) were treated both PVE and Y90 embolization. The mCRC patients received resin microspheres and the HCC patients received glass microspheres. 12 patients had PVE prior to Y90. Nine patients had Y90 after PVE for treatment of liver tumors after aborted surgery. Three patients had Y90 after PVE to induce further hypertrophy. Median time from PVE to Y90 was 250 days (65 – 1253). Two patients with HCC had Y90 prior to PVE with a median time from Y90 to PVE of 24 days (22 and 25). The combination treatment was performed for preoperative treatment and induction of hypertrophy. One patient was successfully resected. The median injected activity was 53 mCi (23 -139). No CTCAE 5.0 grade 3 or higher adverse events were seen at 30- and 90-day follow-up. Median survival of the entire cohort was 490 days. Treatment of HCC and metastatic CRC with a combination PVE and Y90 is safe and may be used to tumor control and induction of liver hypertrophy in select patients.

Current role of trisectionectomy for hepatopancreatobiliary malignancies.

BackgroundTrisectionectomy is a treatment option in extensive liver malignancy, including colorectal liver metastases (CRLM). However, the reported experience of this procedure is limited. Therefore, we present our experience with right hepatic trisectionectomy (RHT) for CRLM as an example and discuss the changing role of trisectionectomy in the context of modern treatment alternatives based on a literature review.MethodsBetween January 1993 and December 2014 all patients undergoing RHT at a single center in the UK for CRLM were included. Patient and tumor characteristics were reviewed and a multivariate analysis was done. Based on a literature review the role of trisectionectomy in the treatment of HPB malignancies was discussed.ResultsA total of 211 patients undergoing RHT were included. Overall perioperative morbidity was 40.3%. Overall 90‐day mortality was 7.6% but reduced to 2.8% over time. Multivariate analysis identified additional organ resection (P = .040) and blood transfusion (P = .028) as independent risk factors for morbidity. Multiple tumors, total hepatic vascular exclusion, and R1 resection were independent risk factors for significantly decreased disease‐free and disease‐specific survival. Further surgery for recurrence after RHT significantly prolonged survival compared with palliative chemotherapy only.ConclusionWith the further development of surgical and multimodal treatment strategies in CRLM the indications for trisectionectomy are decreasing. Having being formerly associated with high rates of perioperative morbidity and mortality, this single‐center experience clearly shows that these concomitant risks decrease with experience, liberal use of portal vein embolization and improved patient selection. Trisectionectomy remains relevant in selected patients.

15-year experience in the use of portal vein embolization in patients with focal liver diseases

Background. Portal vein embolization allows increa­sing the future remnant liver in patients with malignant hepatic neoplasms, preparing for radical surgical treatment. The wide spread of this technique is interfered by the lack of a single execution algorithm. The purpose of this study was to analyze 15-year experience of preoperative portal vein embolization in patients with advanced liver tumors. Materials and methods. From 2003 to 2017 in the department of endovascular surgery of O.O. Shalimov National Institute of Surgery and Transplantology of the NAMS of Ukraine, 485 preoperative embolizations of the portal vein branches were performed in patients with liver tumors, the future remnant liver in which was below the threshold resectabi­lity level. Results. As a result of portal vein embolization, it was possible to achieve the future remnant liver increase by 88.2 % (from 237 to 446 cm3). It allowed performing the radical liver resection in 421 (86.8 %) patients. The analysis of laboratory data showed that the processes of hepatocytolysis associated with embolization and reduction of the synthetic function of the liver are reversible and complete within 3 weeks. Conclusions. Preoperative embolization of the portal vein branches makes it possible to expand the range of resectability of patients with advanced liver tumors and to reduce the risk of postoperative acute hepatic insufficiency.

Beyond the Knife: The Evolving Nonsurgical Management of Oligometastatic Colorectal Cancer.

In patients with liver-limited oligometastatic disease, the goal of treatment can be curative intent. Historically, this was accomplished in patients presenting with upfront resectable disease. The availability of increasingly efficacious chemotherapy and biologic combinations with encouraging response rates led to the potential to convert unresectable disease to resectability. Beyond the backbone of surgery, we now have a portfolio of locoregional strategies to consider.From an interventional radiology perspective, the use of portal vein embolization can facilitate hypertrophy of the liver in anticipation of resection, thus converting unresectable disease to one amenable to a surgical approach with curative intent. Technological advances in liver-directed ablative therapies have afforded the possibility of eliminate radiographically evident disease with the hope for long-term disease control. Advanced radiotherapy techniques are further increasing the therapeutic options for patients with metastatic colorectal cancer. Improvements in external-beam radiotherapy over the past 2 decades include image-guided radiotherapy, intensity-modulated radiotherapy, stereotactic body radiotherapy, and proton-beam therapy. Finally, selective internal radiation therapy (SIRT) with microspheres labeled with the β-emitter 90Y enable targeted delivery of radiation to hepatic tumors. A coordinated multidisciplinary approach is required to integrate these nonsurgical adjuncts in an evidence-based manner to optimize outcomes for patients with potentially resectable metastatic disease. In this article, we summarize recent developments in systemic therapy, radiotherapy, and interventional liver-directed therapies that have changed the treatment landscape for patients with oligometastatic colorectal cancer.

Parenchymal sparing surgery for colorectal liver metastases: The need for a common definition.

e15013 Background: Colorectal cancer metastases (CRLM) are major public health issue. Recently, surgeons have advocated the use of parenchymal sparing surgery (PSS) however, a common definition of the concept is lacking.To clarify and try to validate the concept of PSS to treat CRLM through the available retrospectives studies, including ours. Methods: Retrospective analysis of a cohort of patients treated by combined resections and intra-operative ablation (IOA) based on PSS, prospectively recorded in a database from 2003 to 2015 in a regional referral cancer center. All the patients benefited from the same strategy, constituting a homogenous series.PSS consists of using resection or IOA in order to spare the healthy parenchyma. One-stage is favored over two-stage surgery and use of portal vein embolization was restricted to the minimum.Post-operative complications were the primary endpoint with a special focus on post-operative liver failure. Liver toxicities and overall survival were also scrutinized. Results: Three hundred and eighty-seven patients underwent a PSS out of which 348 patients received a median of 9 pre-operative cycles of oxaliplatin or irinotecan with targeted therapies for half of them. Resection was major in 128 patients, combined with IOA in 137 patients and IOA alone in 50 cases. Thirty-eight patients had a PVO by strict necessity. The 5yr-overall survival was 50.3%. Seventy-eight patients had a complication > grade 3 out of which 10 patients died. Nine patients had a liver failure (LF) grade B and C and four died. There was no difference in post-operative complications comparing minor and major resections, validating our PSS definition. Chemotherapy and liver toxicity were not related to more post-operative complications. Only one patient died from a primitive LF. Conclusions: With PSS, healthy liver is no more a target. Routine use of chemotherapy does not impair the results and severe LFs are rare. PSS is the optimal strategy to treat CRLM. Definition of PSS cannot be based just on the retrived volume but on the ratio Tumor burden/Healthy liver. A major hepatectomy can be a PSS and a minor may not be one. That is why PSS defintion must be clarify especially for further prospective validations.

Measurement of liver function using hepatobiliary scintigraphy improves risk assessment in patients undergoing major liver resection

Background99mTc-mebrofenin-hepatobiliary-scintigraphy (HBS) enables measurement of future remnant liver (FRL)-function and was implemented in our preoperative routine after calculation of the cut-off value for prediction of postoperative liver failure (LF). This study evaluates our results since the implementation of HBS. Additionally, CT-volumetric methods of FRL-assessment, standardized liver volumetry and FRL/body-weight ratio (FRL-BWR), were evaluated. Methods163 patients who underwent major liver resection were included. Insufficient FRL-volume and/or FRL-function <2.7%/min/m2 were indications for portal vein embolization (PVE). Non-PVE patients were compared with a historical cohort (n = 55). Primary endpoints were postoperative LF and LF related mortality. Secondary endpoint was preoperative identification of patients at risk for LF using the CT-volumetric methods. Results29/163 patients underwent PVE; 8/29 patients because of insufficient FRL-function despite sufficient FRL-volume. According to FRL-BWR and standardized liver volumetry, 16/29 and 11/29 patients, respectively, would not have undergone PVE. LF and LF related mortality were significantly reduced compared to the historical cohort. HBS appeared superior in the identification of patients with increased surgical risk compared to the CT-volumetric methods. DiscussionImplementation of HBS in the preoperative work-up led to a function oriented use of PVE and was associated with a significant decrease in postoperative LF and LF related mortality.

Preoperative portal vein embolization for hepatocellular carcinoma: Consensus and controversy.

Thirty years have passed since the first report of portal vein embolization (PVE), and this procedure is widely adopted as a preoperative treatment procedure for patients with a small future liver remnant (FLR). PVE has been shown to be useful in patients with hepatocellular carcinoma (HCC) and chronic liver disease. However, special caution is needed when PVE is applied prior to subsequent major hepatic resection in cases with cirrhotic livers, and volumetric analysis of the liver segments in addition to evaluation of the liver functional reserve before PVE is mandatory in such cases. Advances in the embolic material and selection of the treatment approach, and combined use of PVE and transcatheter arterial embolization/chemoembolization have yielded improved outcomes after PVE and major hepatic resections. A novel procedure termed the associating liver partition and portal vein ligation for staged hepatectomy has been gaining attention because of the rapid hypertrophy of the FLR observed in patients undergoing this procedure, however, application of this technique in HCC patients requires special caution, as it has been shown to be associated with a high morbidity and mortality even in cases with essentially healthy livers.

Role of surgery in colorectal cancer liver metastases.

Colorectal carcinoma (CRC) is the third most common cancer, and approximately 35%-55% of patients with CRC will develop hepatic metastases during the course of their disease. Surgical resection represents the only chance of long-term survival. The goal of surgery should be to resect all metastases with negative histological margins while preserving sufficient functional hepatic parenchyma. Although resection remains the only chance of long-term survival, management strategies should be tailored for each case. For patients with extensive metastatic disease who would otherwise be unresectable, the combination of advances in medical therapy, such as systemic chemotherapy (CTX), and the improvement in surgical techniques for metastatic disease, have enhanced prognosis with prolongation of the median survival rate and cure. The use of portal vein embolization and preoperative CTX may also increase the number of patients suitable for surgical treatment. Despite current treatment options, many patients still experience a recurrence after hepatic resection. More active systemic CTX agents are being used increasingly as adjuvant therapy either before or after surgery. Local tumor ablative therapies, such as microwave coagulation therapy and radiofrequency ablation therapy, should be considered as an adjunct to hepatic resection, in which resection cannot deal with all of the tumor lesions. Formulation of an individualized plan, which combines surgery with systemic CTX, is a necessary task of the multidisciplinary team. The aim of this paper is to discuss different approaches for patients that are treated due to CRC liver metastasis.

Role of surgery in colorectal liver metastases: Too early or too late?

As colorectal cancer and colorectal liver metastases become a serious public health problem, new treatment modalities are needed in order to achieve better results. In the last decade there has been very important progress in oncology, with new and more effective chemotherapeutic agents administered alone or in combination improving the resectability rate in up to 40% of patients with colorectal liver metastases. Advances in interventional radiology, in particular, with the use of portal vein embolization and radiofrequency thermal ablation are new strategies allowing major liver resections and treatment of small liver metastases or early recurrences. Surgery, however, remains the gold standard strategy with intention to treat. In this review article we will describe the advanced role of surgery in the multidisciplinary approach to colorectal liver metastases, and the clinical problems the liver surgeon has to deal with, such as the resectability of the metastases, the presence of bilobar liver lesions and extrahepatic disease, the impact of chemotherapy in already resectable liver metastases, the problem of vanishing metastases after chemotherapy and the dilemma of staged or combined liver and colon operations and which organ first in the clinical scenario of synchronous colorectal liver metastases.

Strategies for Resection Using Portal Vein Embolization: Metastatic Liver Cancer

The oncological landscape is constantly changing with the development of new curatively intended therapeutic strategies. More and more, liver metastases are amenable to resection following the progress achieved as a result of new oncological concepts (i.e., treat detectable disease with surgery and ablative therapies and treat the remaining nondetectable disease with efficient chemotherapy) as well as improved chemotherapeutic and ablation techniques. One of the major limitations to extending the indications for liver resection is the volume of the future remnant liver (FRL). To overcome these limitations, portal vein embolization (PVE) has played a key role in obtaining preoperative hypertrophy of the FRL and thus has reduced postoperative morbidity and mortality. Interestingly, thermal ablation of multiple bilateral liver metastases makes it difficult to predict the volume of parenchyma scheduled for ablation. Furthermore, prolonged chemotherapy impairs liver parenchyma function, which has a negative impact on liver hypertrophy. In the future, both volumetric and functional assessment of the FRL will be used to determine whether PVE is necessary before hepatectomy in individual patients and new strategies (e.g., PVE used alone or combined with other treatments; timing of PVE may vary) will be based on these principles. This article presents various current strategies for the use of PVE in patients with metastatic liver cancer.

Guidelines for the management of biliary tract and ampullary carcinomas: surgical treatment

The only curative treatment in biliary tract cancer is surgical treatment. Therefore, the suitability of curative resection should be investigated in the first place. In the presence of metastasis to the liver, lung, peritoneum, or distant lymph nodes, curative resection is not suitable. No definite consensus has been reached on local extension factors and curability. Measures of hepatic functional reserve in the jaundiced liver include future liver remnant volume and the indocyanine green (ICG) clearance test. Preoperative portal vein embolization may be considered in patients in whom right hepatectomy or more, or hepatectomy with a resection rate exceeding 50%–60% is planned. Postoperative complications and surgery-related mortality may be reduced with the use of portal vein embolization. Although hepatectomy and/or pancreaticoduodenectomy are preferable for the curative resection of bile duct cancer, extrahepatic bile duct resection alone is also considered in patients for whom it is judged that curative resection would be achieved after a strict diagnosis of its local extension. Also, combined caudate lobe resection is recommended for hilar cholangiocarcinoma. Because the prognosis of patients treated with combined portal vein resection is significantly better than that of unresected patients, combined portal vein resection may be carried out. Prognostic factors after resection for bile duct cancer include positive surgical margins, especially in the ductal stump; lymph node metastasis; perineural invasion; and combined vascular resection due to portal vein and/or hepatic artery invasion. For patients with suspected gallbladder cancer, laparoscopic cholecystectomy is not recommended, and open cholecystectomy should be performed as a rule. When gallbladder cancer invading the subserosal layer or deeper has been detected after simple cholecystectomy, additional resection should be considered. Prognostic factors after resection for gallbladder cancer include the depth of mural invasion; lymph node metastasis; extramural extension, especially into the hepatoduodenal ligament; perineural invasion; and the degree of curability. Pancreaticoduodenectomy is indicated for ampullary carcinoma, and limited operation is also indicated for carcinoma in adenoma. The prognostic factors after resection for ampullary carcinoma include lymph node metastasis, pancreatic invasion, and perineural invasion.

Two Hundred Forty Consecutive Portal Vein Embolizations Before Extended Hepatectomy for Biliary Cancer

To assess clinical benefit of portal vein embolization (PVE) before extended, complex hepatectomy for biliary cancer. Many investigators have addressed clinical utility of PVE before simple hepatectomy for metastatic liver cancer or hepatocellular carcinoma, but few have reported PVE before hepatectomy for biliary cancer due to the limited number of surgical cases. This study involved 240 consecutive patients with biliary cancer (150 cholangiocarcinomas and 90 gallbladder cancers) who underwent PVE before an extended hepatectomy (right or left trisectionectomy or right hepatectomy). All PVEs were performed by the "ipsilateral approach" 2 to 3 weeks before surgery. Hepatic volume and function changes after PVE were analyzed, and the outcome also was reviewed. There were no procedure-related complications requiring blood transfusion or interventions. Of the 240 patients, 47 (19.6%) did not undergo subsequent hepatectomy. The incidence of unresectability was higher in gallbladder cancer than in cholangiocarcinoma (32.2% versus 12.0%, P < 0.005). The remaining 193 patients (132 cholangiocarcinomas and 61 gallbladder cancers) underwent hepatectomy with resection of the caudate lobe and extrahepatic bile duct (n = 187), pancreatoduodenectomy (n = 42), and/or portal vein resection (n = 63). Seventeen (8.8%) patients died of postoperative complications: mortality was higher in gallbladder cancer than in cholangiocarcinoma (18.0% versus 4.5%, P < 0.05); and it was also higher in patients whose indocyanine green clearance (KICG) of the future liver remnant after PVE was <0.05 than those whose index was >or=0.05 (28.6% versus 5.5%, P < 0.001). The 3- and 5-year survival after hepatectomy was 41.7% and 26.8% in cholangiocarcinoma and 25.3% and 17.1% in gallbladder cancer, respectively (P = 0.011). In 136 other patients with cholangiocarcinoma who underwent a less than 50% resection of the liver without PVE, a mortality of 3.7% and a 5-year survival of 27.6% were observed, which was similar to the 132 patients with cholangiocarcinoma who underwent extended hepatectomy after PVE. PVE has the potential benefit for patients with advanced biliary cancer who are to undergo extended, complex hepatectomy. Along with the use of PVE, further improvements in surgical techniques and refinements in perioperative management are necessary to make difficult hepatobiliary resections safer.

CASH (Chemotherapy-Associated Steatohepatitis) Costs

CASH (Chemotherapy-Associated Steatohepatitis) Costs

Surgical Management of Hilar Cholangiocarcinoma

To assess the surgical management of hilar cholangiocarcinoma over a time period when liver resection was considered standard management. Hilar cholangiocarcinoma remains a difficult challenge for surgeons. An advance in surgical treatment is the addition of liver resection to the procedure. However, liver resection in the setting of liver dysfunction caused by biliary obstruction can be associated with increased mortality. Between 1997 and 2004, 80 patients with hilar cholangiocarcinoma having surgery were reviewed. Fifty-three patients had attempted curative resections, 14 patients had palliative bypasses, while 13 patients had findings that precluded any further intervention. Twenty-three patients required portal vein resection and reconstruction to achieve negative margins, 3 of which also required reconstruction of the hepatic artery. Patients undergoing resection had a 9% operative mortality, with morbidity of 40%. Patients who demonstrated lobar hypertrophy preoperatively due to tumor involvement of the contralateral liver or induced with portal vein embolization (PVE) had a significantly lower operative mortality than those patients without hypertrophy. Median overall survival in patients resected was 40 months, with 5-year survival of 35%. Negative margins were achieved in 80% of cases and were associated with improved survival. Five-year survival in patients undergoing resection with negative margins was 45%. Combined liver and bile-duct resection can be performed for hilar cholangiocarcinoma with acceptable mortality, though higher than that for liver resections performed for other indications. The use of PVE in cases where hypertrophy of the remnant liver has not occurred preoperatively may reduce the risk of operative mortality.

Portal vein embolization: rationale, technique and future prospects.

Advances in surgery have reduced the mortality rate after major liver resection, but complications resulting from inadequate postresection hepatic size and function remain. Portal vein embolization (PVE) was proposed to induce hypertrophy of the anticipated liver remnant in order to reduce such complications. The techniques, measurement methods and indications for this treatment remain controversial. A Medline search was performed to identify papers reporting the use of PVE before hepatic resection. Techniques, complications and results are reviewed. Complications of PVE typically occur in less than 5 per cent of patients. No specific substance (cyanoacrylate, thrombin, coils or absolute alcohol) emerged as superior. The increase in remnant liver volume averages 12 per cent of the total liver. The morbidity rate of resection after treatment is less than 15 per cent and the mortality rate is 6-7 per cent with cirrhosis and 0-6.5 per cent without cirrhosis. Embolization is currently used for patients with a normal liver when the anticipated liver remnant volume is 25 per cent or less of the total liver volume, and for patients with compromised liver function when the liver remnant volume is 40 per cent or less. This treatment does not increase the risks associated with major liver resection. It may be indicated in selected patients before major resection. Future prospective studies are needed to define more clearly the indications for this evolving technique.

Portal vein embolization with steel coils and absolute ethanol: A comparative experimental study with canine liver

Portal vein embolization (PVE) is expected to have an adjuvant effect on the treatment of human liver tumors with transcatheter hepatic arterial embolization (TAE). In this experimental study, PVE was tried using two kinds of embolic materials, steel coils (coils) and absolute ethanol (ethanol). The aim of this article is to compare the effectiveness between the two methods. Five dogs and 12 dogs were treated with coils and ethanol, respectively. The second order portal branches were embolized. Embolization effects of each embolic material on the hepatic vessels and the liver parenchyma were studied angiographically and histologically. PVE with coils achieved immediate occlusion of the embolized vessels in all dogs. Unexpectedly, unembolized vessels were also constricted and/or obstructed in 4 of 5 dogs during a 4-week follow-up period. Histological examination showed no hepatic necrosis in all dogs. By contrast, in the dogs treated with ethanol, venous occlusion was achieved immediately after embolization with ethanol of 0.4 mL/kg or more. The embolized vessels remained occluded and no obstruction of unembolized vessels was observed until 4 weeks after embolization. Hepatic necrosis was observed in the segments where portal veins were occluded. The degree of parenchymal damage was proportional to the injected ethanol dose. Judging from these results, ethanol is likely to be more suitable than coils as an embolic material for PVE. PVE with coils is often dangerous because unembolized vessels might be occluded unexpectedly. For the clinical use of PVE with ethanol, the appropriate dose of injection should be investigated.

Portal vein embolization with steel coils and absolute ethanol: A comparative experimental study with canine liver

Portal vein embolization (PVE) is expected to have an adjuvant effect on the treatment of human liver tumors with transcatheter hepatic arterial embolization (TAE). In this experimental study, PVE was tried using two kinds of embolic materials, steel coils (coils) and absolute ethanol (ethanol). The aim of this article is to compare the effectiveness between the two methods. Five dogs and 12 dogs were treated with coils and ethanol, respectively. The second order portal branches were embolized. Embolization effects of each embolic material on the hepatic vessels and the liver parenchyma were studied angiographically and histologically. PVE with coils achieved immediate occlusion of the embolized vessels in all dogs. Unexpectedly, unembolized vessels were also constricted and/or obstructed in 4 of 5 dogs during a 4-week follow-up period. Histological examination showed no hepatic necrosis in all dogs. By contrast, in the dogs treated with ethanol, venous occlusion was achieved immediately after embolization with ethanol of 0.4 mL/kg or more. The embolized vessels remained occluded and no obstruction of unembolized vessels was observed until 4 weeks after embolization. Hepatic necrosis was observed in the segments where portal veins were occluded. The degree of parenchymal damage was proportional to the injected ethanol dose. Judging from these results, ethanol is likely to be more suitable than coils as an embolic material for PVE. PVE with coils is often dangerous because unembolized vessels might be occluded unexpectedly. For the clinical use of PVE with ethanol, the appropriate dose of injection should be investigated.

Results of treatment of patients with hepatocellular carcinoma with severe cirrhosis of the liver

We retrospectively classified patients with hepatocellular carcinoma by the results of tests of 15-minute indocyanine green retention (ICGR15). Of the 201 patients with hepatocellular carcinoma admitted to our department in the past 6 years, 36 patients were assigned to group 1 (ICGR15 less than 10.0%), 81 patients to group 2 (ICGR15 = 10.1-20.0%), and 84 patients to group 3 (ICGR15 greater than or equal to 20.1%). Of the total 201 patients, 72% underwent liver resection (78% of group 1 patients, 80% of group 2 patients, and 62% of group 3 patients). We regarded the cirrhosis of the patients in group 3 as severe and studied their survival rate classified by the treatment used. Of these 84 patients, 52 patients were treated by liver resection, about half of whom were treated preoperatively by transcatheter arterial embolization (TAE). Another 9 patients were treated preoperatively by both TAE and portal vein embolization (PVE). At 2 years, and again at 3 years, the survival rate was significantly higher when TAE was used preoperatively than with resection alone. We think that the possibility of performing needed liver resection will be enlarged by preoperative PVE and that liver resection can be done more safely after use of PVE in some patients.