Efficacy and safety of preoperative percutaneous transhepatic portal embolization with absolute ethanol: a clinical study

Portal vein embolization in hilar cholangiocarcinoma

In patients with hilar cholangiocarcinoma, extended hepatectomy and caudate lobe resection are often performed to achieve an R0 resection. In patients whose standardized future liver remnant is less than or equal to 20% of total liver volume, portal vein embolization (PVE) should be performed. In patients with biliary dilatation of the future liver remnant, a biliary drainage catheter should be placed before PVE. If the planned surgery is an extended right hepatectomy, segment 4 branch embolization improves the hypertrophy of segments 2 and 3. In high-volume centers, PVE can be safely performed; it increases the resectability rate and results in the same survival rates as those in patients who undergo resection without PVE.

Preoperative portal vein embolization using an amplatzer vascular plug

The purpose was to evaluate the safety and efficacy of preoperative portal vein embolization (PVE) using an Amplatzer vascular plug (AVP). Forty-one patients who underwent PVE using gelatin sponge particles and the AVP were enrolled. The right portal branches were embolized using gelatin sponges (1-8 mm(3)) through a 5-F catheter, and the AVP was deployed at the first- or second-order right portal vein. Technical success and complications, recanalization, and changes of total estimated liver volumes (TELV), future liver remnant (FLR), and FLR/TELV were evaluated. Follow-up CT performed 6-43 days (median, 16 days) after PVE was used to evaluate volume parameters. PVE was technically successful in 40 of 41 patients. Major complications occurred in two patients, with one each having extensive portal vein thrombosis and liver abscess. Partial recanalization of the occluded portal vein was seen in one patient. The mean FLR volume (653 +/- 174 ml vs. 532 +/- 154 ml, p < 0.001) and mean FLR/TELV ratio (43 +/- 8% vs 36 +/- 7%, p < 0.001) were significantly higher after than before PVE. PVE using the AVP seems to be a relatively safe and effective technique for inducing hypertrophy of the FLR with minimal risk of recanalization.

Mesohepatectomy as an option for the treatment of central liver tumors

BACKGROUND

Despite substantial improvements in intra- and postoperative management of extended hemihepatectomy as the curative option for treatment of central liver tumors, the high morbidity and mortality rates accompanying the procedure still represent major obstacles. Mesohepatectomy preserves up to 35% more functional liver tissue than extended hepatectomy, but it has not been widely applied, perhaps because of its complexity as a resection method.

STUDY DESIGN

Forty-eight consecutive patients (29 men and 19 women) with centrally located liver tumors underwent mesohepatectomy. Peri- and postoperative morbidity and mortality rates were prospectively evaluated and analyzed. Mean age of the patients was 60.7 years. Indications for mesohepatectomy were liver metastasis (n = 29), hepatocellular carcinoma (n = 5), gallbladder carcinoma (n = 4), cholangiocellular carcinoma (n = 4), hemangioma (n = 2), and other benign diseases (n = 4).

RESULTS

Mean operative time was 238 minutes (range 65 to 480 minutes) and mean intraoperative blood loss was 1,120 mL (range 100 to 5,000 mL). Mean amount of intraoperative red blood cells and fresh frozen plasma transfusion was 3.6 U (range 1 to 12 U) and 3.8 U (range 2 to 14 U), respectively. Mean postoperative hospitalization was 15.8 days (range 6 to 104 days). Postoperative surgical complications were seen in 18.8% of patients (n = 9) and included liver failure (n = 1), intraabdominal abscess (n = 1), bilioma or bile leakage (n = 4), hemorrhage and hematoma (n = 2), peritonitis because of intestinal perforation (n = 1), and wound infection (n = 1). One patient (2%) died in the early postoperative phase from portal vein bleeding and disseminated intravascular coagulation, followed by liver failure.

CONCLUSIONS

Compared with extended liver resection, mesohepatectomy clearly leads to less parenchymal loss. Although it is a technically difficult operation and requires special attention to prevent surgical complications, it is justified in selected patients with centrally located tumors and is a feasible and safe alternative to extended liver resection.

Feasibility of laparoscopic portal vein ligation prior to major hepatectomy

BACKGROUND

Patients noted to have an inadequate future liver remnant on pre operative volumetric assessment are considered to be candidates for portal vein embolization (PVE). A subset of patients undergo laparoscopic intervention prior to PVE for staging purposes or to address the primary in Stage IV colon cancer. These patients usually undergo PVE as a subsequent additional procedure by the transhepatic route. The aim of this study was to assess the feasibility of portal vein ligation by the laparoscopic approach in suitable patients.

MATERIALS AND METHODS

A retrospective review of a prospectively maintained database was performed to identify patients that underwent laparoscopic portal vein ligation (LPVL). The demographic, clinical, radiographic, operative and volumetric details were collected to determine the feasibility of portal vein ligation.

RESULTS

A total of nine patients underwent LPVL as part of a two stage procedure in preparation for subsequent major hepatectomy. With a median age of 67 yrs, the diagnoses included: colorectal metastasis (five patients), cholangiocarcinoma (three patients) and hepatocellular carcinoma (one patient). The ligation involved the right portal vein in all and was performed with silk ligature (seven patients) and clips (two patients). Volumetric data was available in six patients which showed a mean increase from 209.1 cc+/-97.76 to 495.83 cc+/-310.91 (increase by 181.5%) In two patients, inadequate hypertrophy mandated later embolization by percutaneous technique. Five patients underwent subsequent major hepatic resection as planned. The remaining four patients were noted to have progression of disease that precluded the planned procedure. There were no complications associated with LPVL.

CONCLUSIONS

LPVL is feasible and can be safely performed. In a select group of patients, it may be considered as an alternative to subsequent embolization and thereby potentially absolve the need for an additional procedure with its attendant complications.

Preoperative contralateral portal vein embolization before major hepatic resection is a safe and efficient procedure: a large single institution experience

BACKGROUND

The aim of this study was to report the results of preoperative contralateral portal vein embolization (PVE) performed in a single institution.

METHODS

Between January 1997 and March 2006, 146 patients requiring a right or extended right hepatectomy for primary or secondary liver tumors underwent contralateral PVE when the future remnant liver volume (FRL) was less than 30% of total liver. Liver volumes and hepatic function were evaluated before and after PVE.

RESULTS

Contralateral PVE was performed successfully in 145 patients. In one patient, the catheterization of the left portal branch failed. Complications occurred in 14 patients (10%) including a transitory fever (n = 9), a parenchymal hematoma (n = 1), a mild hemoperitoneum (n = 1), a mesenterico-portal venous thrombosis (n = 1), a pulmonary embolism (n = 1) and a systemic sepsis (n = 1). The prothrombin ratio and the platelet count were significantly lower 3 days after PVE. Insufficient hypertrophy of the FRL was observed in 8 patients, malignant disease progression in 15, and both insufficient hypertrophy and disease progression in 4. The hypertrophy rate of the FRL 4 to 8 weeks after PVE was 47.7 +/- 31.9%. Pathological type of the liver tumor, cirrhosis, diabetes mellitus, and chemotherapy did not affect the volume of the left liver hypertrophy. However, the time required to achieve an adequate liver hypertrophy was significantly shorter in patients with normal liver. One-hundred and fourteen patients (78.6%) subsequently underwent hepatic resection.

CONCLUSIONS

The results suggest that contralateral PVE is a safe and efficient procedure inducing adequate hypertrophy of the FRL before major liver resection.

Preoperative portal vein embolization for major liver resection: a meta-analysis

INTRODUCTION

Preoperative portal vein embolization (PVE) is used clinically to prevent postoperative liver insufficiency. The current study examined the impact of portal vein embolization on liver resection.

METHOD

A comprehensive Medline search to identify all registered literature in the English language on portal vein embolization. Meta-analysis was performed to assess the result of PVE and its impact on major liver resection.

RESULT

A total of 75 publications met the search criteria but only 37 provided data sufficiently enough for analysis involving 1088 patients. The overall morbidity rate for PVE was 2.2% without mortality. Four weeks following PVE, 85% patients underwent the planned hepatectomy (n = 930). Twenty-three patients had transient liver failure following resection after PVE (2.5%) but 7 patients developed acute liver failure and died (0.8%). The reason for nonresection following PVE (n = 158, 15%) included inadequate hypertrophy of remnant liver (n = 18), severe progression of liver metastasis (n = 43), extrahepatic spread (n = 35), refusal to surgery (n = 1), poor general condition (n = 1), altered treatment to transcatheter artery embolization or chemotherapy (n = 24), complete remission after treatment with 3 cycles of fluoracil and interferon alpha in a patient with hepatocellular carcinoma (n = 1), incomplete pre- or postembolization scanning (n = 8). Of those who underwent laparotomy without resection, (n = 27) reasons included intraoperative finding of peritoneal dissemination (n = 15), portal node metastasis (n = 2), severe invasion of the tumor to the hepatic artery and portal vein (n = 1), and gross tumoral extension precluding curative resection (n = 9). Two techniques were used for portal vein embolization: percutaneous transhepatic portal embolization, (PTPE) and transileocolic portal embolization, (TIPE). The increase in remnant liver volume was much greater in PTPE than TIPE group (11.9% vs. 9.7%; P = 0.00001). However, the proportion of patients who underwent resection following PVE was 97% in TIPE and 88% PTPE, respectively (P = <0.00001). Although there was no significant difference in patients who had major complications post-PVE, the rate for minor complications was significantly higher among patients who had PTPE (53.6% vs. 0%, P = <0.0001).

CONCLUSION

PVE is a safe and effective procedure in inducing liver hypertrophy to prevent postresection liver failure due to insufficient liver remnant.

Recent advances in the treatment of hilar cholangiocarcinoma: portal vein embolization

The clinical application of portal vein embolization (PVE) has contributed to improving the postoperative outcome of hilar cholangiocarcinoma. The enlarged nonembolized lobe after PVE protects the patient from postoperative hepatic failure, due to the increased functional reserve, and shortens the hospital stay. Although numerous reports have shown beneficial effects of PVE on postoperative outcome after extended hepatectomy, no randomized controlled study has been performed so far. It is urgent to establish a "gold standard" of PVE, because the indications, approach to the portal vein, types of embolic materials, and methods used to evaluate the function of the future liver remnant are variable among institutions. The indications and procedures of PVE for hilar cholangiocarcinoma may be different from those for hepatocellular carcinoma or colorectal metastasis, because, in many patients with hilar cholangiocarcinoma, biliary cancer is associated with biliary obstruction and cholangitis. This review article summarizes the contribution of PVE to the outcome of postoperative management in patients with hilar cholangiocarcinoma needing extended hepatectomy. We also describe our PVE procedure, which has been established from our experience of more than 240 cases of biliary cancer. Furthermore, the drawbacks of PVE, which may reduce the pool of candidates for surgery, are also discussed.

Liver Embolizations in Oncology. A Review. Part II. Arterial Radioembolizations, Portal Venous Embolizations, Experimental Arterial Embolization Procedures

Arterial embolization of the liver may temporarily retard the growth of its primary and secondary tumors which are both mainly nourished arterially. Addition of radioisotopes, mostly (131)I or (90)Y, results in radioembolizations which predominantly act by radiation and less by ischemia. They may therefore be utilized in the absence of portal venous flow when conventional embolization is hazardous. (131)I-oily radioembolization seems to prolong short-term survival in such patients with unresectable hepatocellular cancers, and to improve the prognosis after resection of hepatocellular cancer. The procedure does however not palliate better than "cold" chemoembolization in patients with preserved portal flow, except for having milder side effects. Embolization with (90)Y-coupled microspheres may shrink primary and secondary liver tumors but has so far unproven effects on survival. Embolization of portal venous branches gives compensatory hypertrophy of the non-embolized liver and can increase the volume of the future remnant liver before resection. This diminishes the risk for postoperative liver failure after extensive resection and/or in the presence of chronic liver disease, and permits wider surgical indications. Tumor growth may however be accelerated, and the hypertrophy is inhibited by severe liver parenchymal disease in which situation the method would be most needed. Experimental use of liver arterial embolizations includes combined arterial and portal embolizations, i.e. "chemical hepatectomy," arterial embolizations before external radiotherapy, administration of boron for neutron capture therapy, immunoembolizations, and future gene therapy.

Liver regeneration: mechanisms, mysteries and more

BACKGROUND

Liver regeneration remains a fascinating topic, still partly clouded to many as to the exact cellular and molecular mechanisms that bring about this phenomenon. It is an area, therefore, of active research today. This review looks at the recent published reports that have led to a greater understanding of this process.

METHODS

A database search was carried out on Medline search using the terms liver regeneration with no linguistic limitations from 1966 to 2006.

RESULTS

There are two randomized controlled trials on the topic and most data and information have come from experimental studies in animals.

CONCLUSION

Liver regeneration is a complex, tightly controlled process involving many inflammatory cells growth factors and hormones. More information about it is awaited in studies on humans.

Assessment of future remnant liver regeneration after portal vein embolization using three-dimensional CT and MR volumetric analyses

The purpose of this study is to portray right portal vein embolization (PVE) as a valuable technique that helps in expanding the volume of the left liver lobe and discuss the relevant published work. We describe our experience with four patients who underwent PVE and analyse the value of CT and MRI in the preoperative evaluation of these patients. Four patients with hepatic malignancy (hepatocellular carcinoma) (n=2) and metastatic liver disease (n=2) underwent portal vein occlusion. PVE was carried out in three patients using polyvinyl alcohol and stainless steel coils. Portal vein ligation was carried out in the fourth patient. In patients who were candidates for right hepatectomy, CT volumetric analysis was carried out before the surgery to assess the total liver volume and the future remnant liver, which is the residual left hepatic volume (in cases of right hepatectomy) or left lateral segment volume (in cases of right tri-segmentectomy). Because the left lobe volumes were insufficient, patients were selected to undergo right PVE. Computed tomography volumetry was carried out 2-4 weeks after embolization to assess left hepatic lobe regeneration. Magnetic resonance volumetric analysis was carried out in two patients before and after embolization. All four patients had significant regeneration of the left lobe and tolerated the surgery with uneventful postoperative recovery.

Transarterial versus Transhepatic Portal Vein Embolization to Induce Selective Hepatic Hypertrophy: A Comparative Study in Swine

PURPOSE

Portal vein embolization (PVE) is used to induce liver hypertrophy for surgical candidates with marginal future liver remnant (FLR) volumes. We compared the feasibility, safety, and effectiveness of a transarterial approach for PVE (TA-PVE) with those of a transhepatic approach for PVE (TH-PVE) in a swine model.

MATERIALS AND METHODS

Ten experimental pigs (TA-PVE, n = 5; TH-PVE, n = 5) and six controls (TA, n = 3; TH, n = 3) were studied. For TA-PVE, a microcatheter was advanced into arteries supplying the left and left middle hepatic lobes. A 3 to 1 Ethiodol-ethanol mixture was infused into selected arteries to cross the arterioportal peribiliary plexus and remain within the portal veins (PVs). For TH-PVE, PVs in the same lobar distribution were embolized with 355- to 500-micro m polyvinyl alcohol particles and coils. Controls were similarly catheterized for saline infusion. Computed tomography with volumetry was performed before and 7, 14, 21, and 28 days after PVE to assess FLR hypertrophy (absolute FLR volume change and FLR/total liver volume [TLV]). Computed tomographic volumetry, laboratory data, and histopathology were compared between groups.

RESULTS

All procedures were technically successful. The increases in mean absolute FLR volume (TA-PVE, 148 +/- 84 cm(3); TH-PVE, 62 +/- 19 cm(3); P = .082), mean FLR hypertrophy (TA-PVE, 93.2%; TH-PVE, 48.4%; P = .178), and mean FLR/TLV (TA-PVE, 31.0%; TH-PVE, 16.2%; P = .130) from day 0 to day 28 between experimental groups were better for TA-PVE. Changes in laboratory data among all groups were minimal. Two complications occurred from TA-PVE (right gastric artery embolization [n = 2] without sequela) and two from TH-PVE (acute segmental right PV thrombosis [n = 1]; death 3 weeks after PVE of unknown cause [n = 1]).

CONCLUSIONS

Transarterial portal vein embolization is feasible, safe, and effective for inducing future liver remnant hypertrophy in swine and may represent an improvement over previously reported transhepatic portal vein embolization methods.

Ipsilateral percutaneous transhepatic portal vein embolization with gelatin sponge particles and coils in preparation for extended right hepatectomy for hilar cholangiocarcinoma

PURPOSE

To evaluate the effectiveness and safety of ipsilateral percutaneous transhepatic portal vein embolization (PTPVE) with gelatin sponge particles and coils to induce lobar hypertrophy in patients with hilar cholangiocarcinoma in preparation for extended right hepatectomy.

MATERIALS AND METHODS

Between 1999 and 2004, PTPVE was performed in 22 patients with hilar cholangiocarcinoma (mean age, 67 years; range, 57-77 y; 16 men and six women). Percutaneous puncture of the right portal vein was performed under ultrasound guidance. A reverse-curve catheter was used for right portal vein embolization. Coils were used to occlude second-order branches. The future liver remnant volume was assessed by comparing computed tomographic scans before and 14-24 days after PTPVE.

RESULTS

PTPVE was technically successful in all cases. The average increase in ratio of future liver remnant volume to total liver volume was 8.6%. Liver function tests after PTPVE but before surgery showed no significant changes. Nineteen patients underwent hepatic resection without liver failure. In three patients, tumors could not be removed because of detection of extrahepatic disease. One patient who underwent successful hepatic resection had an abscess in the removed right lobe.

CONCLUSION

Ipsilateral PTPVE with gelatin sponge and coils appears to be effective and safe for extended right hepatectomy for hilar cholangiocarcinoma.

Sequential arterial and portal vein embolizations before right hepatectomy in patients with cirrhosis and hepatocellular carcinoma

BACKGROUND

Selective transarterial chemoembolization (TACE) and portal vein embolization (PVE) could improve the rate of hypertrophy of the future liver remnant (FLR) in patients with chronic liver disease. This study evaluated the feasibility and efficacy of this combined procedure.

METHODS

Between November 1998 and October 2004, 36 patients with cirrhosis and hepatocellular carcinoma underwent right hepatectomy after PVE. Additional TACE preceded PVE by 3-4 weeks in 18 patients (TACE+PVE group) and the remaining 18 patients had PVE alone (PVE group).

RESULTS

PVE was well tolerated in all patients. The mean increase in percentage FLR volume was significantly higher in the TACE+PVE group than in the PVE group (mean(s.d.) 12(5) versus 8(4) percent; P=0.022). The rate of hypertrophy was more than 10 percent in 12 patients in the TACE+PVE group and in five who had PVE alone (P=0.044). Duration of surgery, blood loss, incidence of liver failure and mortality (two patients in each group) were similar in the two groups. None of the 17 patients with an increase in FLR volume of more than 10 percent died, whereas there were four deaths among 19 patients with a smaller increase. The incidence of complete tumour necrosis was significantly higher in the TACE+PVE group (15 of 18 versus one of 18; P<0.001), with a higher 5-year disease-free survival rate (37 versus 19 percent; P=0.041).

CONCLUSION

Sequential TACE and PVE before operation increases the rate of hypertrophy of the FLR and leads to a high rate of complete tumour necrosis associated with longer recurrence-free survival.

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Parameters Associated with Changes in Liver Volume in Patients Undergoing Portal Vein Embolization

BACKGROUND

To identify predictors of changes in hepatic volumes after portal vein embolization (PVE) before hepatectomy, we examined the relationship between clinicopathological parameters and changes in volume of embolized and nonembolized liver and regeneration of remnant liver after hepatectomy.

MATERIALS AND METHODS

The subjects were 25 patients who underwent laparotomy. PVE was performed through transileocolic vein (n = 15) and percutaneous transhepatic puncture (n = 10).

RESULTS

Significant atrophy and hypertrophy of the embolized and nonembolized liver were observed after PVE, respectively, and further increase of remnant liver volume was observed after hepatectomy. Background liver disease did not seem to influence the results. Alkaline phosphatase (ALP) level correlated negatively with atrophy of embolized lobe (r = -0.433). Platelet count correlated positively with hypertrophy of nonembolized lobe (r = 0.412, P < 0.05) and percent increase between lobes and (r = 0.515, P < 0.05). Seven (32%) patients developed postoperative complications, such as long-term ascites or cholestasis. Changes in embolized liver and percent increase between lobes in patients with postoperative cholestasis (-94 +/- 97 cm(3) and 9.6 +/- 5.1% gain) were significantly lower than those in patients without cholestasis (17 +/- 54 cm(3) and 6.6 +/- 1.3% gain, P < 0.05).

CONCLUSION

ALP and platelet counts might be able to predict PVE effect and were related to postoperative course. Identification of more specific predictors is desirable.

Two hundred forty consecutive portal vein embolizations before extended hepatectomy for biliary cancer: surgical outcome and long-term follow-up

OBJECTIVE

To assess clinical benefit of portal vein embolization (PVE) before extended, complex hepatectomy for biliary cancer.

SUMMARY BACKGROUND DATA

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Interventional procedures involving portal vein circulation: a review

Rapid development of diagnostic radiological methods during recent decades has been followed by development of new interventional procedures involving portal circulation. The majority of these interventions were developed for treatment of patients with symptoms secondary to portal hypertension (PH). Interventions involving portal vein circulation have an established position in the treatment of PH and other diseases, and further development of these methods can be expected.

Percutaneous right portal vein embolization with polyvinyl alcohol particles in gastric cancer metastasis: report of a case

Polyvinyl alcohol (PVA) particles are used for the embolization of various vascular tumors. They are also used before hepatic resection to embolize the ipsilateral portal vein, causing hypertrophy of the remaining liver. We report our first experience with portal vein embolization (PVE) with PVA particles to treat gastric cancer metastasis to the liver. PVE with PVA is a safe interventional radiologic procedure, which does not cause problems during surgery and can improve the outcome of hepatic resection.

Portal Vein Embolization with N-Butyl Cyanoacrylate before Partial Hepatectomy in Patients with Hepatocellular Carcinoma and Underlying Cirrhosis or Advanced Fibrosis

PURPOSE

To describe the safety, complications, and liver regeneration associated with the left liver after embolization of the right portal vein (PV) in patients with hepatocellular carcinoma (HCC) developed in the setting of advanced liver fibrosis and cirrhosis.

MATERIALS AND METHODS

Forty patients (31 men, nine women; mean age, 62 years) with HCC underwent PV embolization over a 4-year period. Embolization was performed from a left PV percutaneous access with use of n-butyl cyanoacrylate (NBCA) mixed with iodized oil. Computed tomography (CT) volumetry was performed before and 1 month after PV embolization to measure the left lobe volume as well as the functional liver ratio defined by the ratio between the left lobe and the total liver volume minus tumoral volume. PV pressure and liver enzyme levels were compared before and 1 month after the procedure and complications were registered. Factors potentially affecting regeneration (age, sex, diabetes, chemoembolization, functional liver ratio before PV embolization, and Knodell histologic score) were evaluated by one-way and stepwise regression analysis.

RESULTS

PV embolization could be achieved successfully in all cases. Two patients had partial PV thrombosis on the 1-month follow-up CT and two patients developed transient ascites after PV embolization. The left lobe volume increase was 41% +/- 32% after PV embolization and the functional liver ratio increased from 28% +/- 10% to 36% +/- 10% (P < .0001). Hypertrophy of the left lobe was greater in patients with a low functional liver ratio before PV embolization and those with an F3 fibrosis score. Other factors had no influence on left lobe regeneration.

CONCLUSION

PV embolization with use of NBCA is feasible in patients with advanced fibrosis and cirrhosis. Hypertrophy of the left lobe of the liver after PV embolization has a statistically significant correlation with lower functional liver ratio and lower degrees of fibrosis.

Safety and Efficacy of Preoperative Portal Vein Embolization with Polyvinyl Alcohol in 58 Patients with Liver Metastases

OBJECTIVE

The objective of our study was to evaluate the safety and efficacy of transhepatic lobar portal vein embolization (PVE) using polyvinyl alcohol (PVA) particles to induce contralateral lobar hypertrophy in patients with liver-only metastases and normal underlying liver function.

MATERIALS AND METHODS

Fifty-eight consecutive patients with small predicted future liver remnants (FLRs) underwent PVE with PVA particles to induce hypertrophy of the contralateral hemi-liver before surgical resection of liver metastases. Total liver, right hemi-liver, and left hemi-liver volumes were calculated before and after embolization using a 3D workstation.

RESULTS

Eight patients underwent left PVE; 47, right PVE; and three, right and segment IV PVE. There were no major complications of the procedure. The mean increases in the ratio of the FLR to the total estimated liver volume after right, right and segment IV, and left PVE were 9%, 10%, and 3%, respectively; the corresponding mean hypertrophy ratios were 24.3%, 31.9%, and 1.5%, respectively.

CONCLUSION

Right PVE using PVA particles alone as the embolic agent is safe and effective in achieving left hemi-liver hypertrophy. In contrast, left PVE did not induce significant right hemi-liver hypertrophy in this patient population.

Portal vein embolization in preparation for major hepatic resection: evolution of a new standard of care

Portal vein (PV) embolization (PVE) is gaining acceptance in the preoperative management of patients selected for major hepatic resection. PVE redirects portal blood flow to the intended liver remnant to induce hypertrophy of the nondiseased portion of the liver and thereby reduce complications and shorten hospital stays after resection. This article reviews the rationale and existing literature on PVE, including the mechanisms of liver regeneration, the pathophysiology of PVE, the imaging techniques used to measure liver volumes and estimate functional hepatic reserve, and the technical aspects of PVE, including approaches and embolic agents used. In addition, the indications and contraindications for performing PVE in patients with and without chronic liver disease and the multidisciplinary approach required for the treatment of these complex cases are emphasized.

Percutaneous transhepatic portal vein embolization: effectiveness of absolute ethanol infusion with balloon catheter in a pig model

PURPOSE

To evaluate the effectiveness of portal vein embolization (PVE) with absolute ethanol using multidetector-row computed tomography (CT) angiography in a pig model.

MATERIAL AND METHODS

Percutaneous transhepatic PVE with 10 ml absolute ethanol was performed in liver segments (n = 5) or subsegments (n = 5) in 10 pigs. CT images and volumetric data were qualitatively and quantitatively assessed to determine future liver remnant (FLR) hypertrophy and to correlate with histopathologic changes 2-6 weeks after PVE. Effectiveness evaluation was based on changes in absolute FLR size and ratio of FLR to total estimated liver volume (TELV).

RESULTS

Occlusion of the embolized vessel was achieved immediately after injecting absolute ethanol within a range of 0.25-0.33 ml/kg. The TELV prior to PVE was 660.49 +/- 103.66 cm3 (range 527.22 to 833.70 cm3) and after PVE 769.51 +/- 29.36 cm3 (range 685.95 to 887.34 cm3). The mean FLR/TELV ratio increase after PVE was 14.2%. No statistically significant difference was found in the increase of TELV between segmental or subsegmental PVE. On microscopic observation, atrophy of the embolized liver was noted in all animals and was seen distinctly at 3 weeks after PVE in 2 animals.

CONCLUSION

Both regenerative response and histopathologic changes of the liver were seen after PVE with absolute ethanol with a mean FLR/TELV ratio of 14.2%.

Surgical therapy of hepatocellular carcinoma

There is no worldwide consensus of an algorithm for the radical treatment of hepatocellular carcinoma (HCC). Surgical resection, liver transplantation and, recently, local ablation therapies achieve high curative rates in selected patients. However, recurrence of HCC remains a major problem. This review provides an overview of the current surgical treatment options available for patients with HCC.

Portal vein embolization before major hepatectomy

To discuss the rationale, techniques and the unsolved issues regarding preoperative portal vein embolization (PVE) before major hepatectomy. After a systematic search of Pubmed, we reviewed and retrieved literature related to PVE. Preoperative PVE is an approach that is gaining increasing acceptance in the preoperative treatment of selected patients prior to major hepatic resection. Induction of selective hypertrophy of the nondiseased portion of the liver with PVE in patients with either primary or secondary hepatobiliary, malignancy with small estimated future liver remnants (FLR) may result in fewer complications and shorter hospital stays following resection. Additionally, PVE performed in patients initially considered unsuitable for resection due to lack of sufficient remaining normal parenchyma may add to the pool of candidates for surgical treatment. The results suggest that PVE is recomm-endable in treating the cirrhotic patients before major liver resection.

Oncolytic herpes simplex virus-1 mutant expressing green fluorescent protein can detect and treat peritoneal cancer

NV1066 is a herpes simplex virus-1 (HSV-1) oncolytic mutant that contains the gene for enhanced green fluorescent protein (EGFP). We sought to determine (1) whether NV1066 is effective against human peritoneal cancer, (2) whether EGFP is detectable in an animal model of gastric cancer, and (3) whether EGFP expression can be used to assess oncolytic therapy in a minimally invasive, laparoscopic system. The current study demonstrates that NV1066 is cytotoxic to OCUM human gastric cancer cells in vitro and in an in vivo model of disseminated peritoneal gastric cancer. In vitro this human gastric cancer cell line is sensitive to NV1066. Lysis occurs in a dose-dependent fashion, achieving near-complete lysis even at multiplicities of infection (MOIs) as low as 0.01 by 7 days. NV1066 also replicates within OCUM cells and induces expression of GFP in a dose-dependent manner. At MOIs of 0.01 to 1, EGFP expression is seen by flow cytometry in 100% of OCUM cells within 5 days after infection. NV1066 effectively treats OCUM carcinomatosis in an in vivo model. After intraperitoneal administration of NV1066, macroscopic tumor foci express EGFP by direct laparoscopy with the appropriate fluorescent filtering. Noncancerous organs are not infected and do not express EGFP. We conclude that NV1066 has significant oncolytic activity in vitro and in vivo and reliably induces EGFP expression in infected tumor cells. Furthermore, EGFP expression in intraperitoneal tumors can be visualized laparoscopically, allowing detection and localization of viral gene therapy.

Infection with oncolytic herpes simplex virus-1 induces apoptosis in neighboring human cancer cells: a potential target to increase anticancer activity

PURPOSE

The antitumor efficacy of a herpes simplex virus (HSV)-1 oncolytic virus depends on the cytotoxic effect of the virus, but also on viral replication and spread within the tumor. Apoptosis is considered a defense mechanism of infected cells that minimizes the spread of viral progeny by limiting cellular production of virus. We sought to determine whether oncolytic HSV-1 infection induces apoptosis in neighboring, uninfected cells and whether manipulation of apoptosis can increase viral replication and cytotoxicity.

EXPERIMENTAL DESIGN

NV1066 is an oncolytic HSV-1 mutant that contains the marker gene for enhanced green fluorescent protein. OCUM human gastric cancer cells were infected with NV1066 in vitro and inspected for apoptosis by Hoechst and terminal deoxynucleotidyltransferase-mediated nick end labeling staining and for infection by expression of green fluorescence.

RESULTS

A significant increase in apoptosis was seen in cells infected by NV1066. More interestingly, a significant percentage (10%) of uninfected cells also proceeded to apoptosis. After NV1066 infection, cells were also treated with N-acetylcysteine (NAC), an inhibitor of apoptosis. By day 4 after infection, 2.7x more NV1066 was produced in cells exposed to NAC than in those not exposed to NV1066 (P = 0.04). NAC also increased tumor kill when administered with virus.

CONCLUSIONS

These data suggest that NV1066 induces apoptosis in uninfected cocultured cells, potentially hindering propagation of viral progeny and concomitant tumor kill. Inhibition of apoptosis may improve the efficacy of oncolytic HSV-1 therapy.

Current role of portal vein embolization/hepatic artery chemoembolization

This article has reviewed indications, methods, and results of PVE and TACE for hepatobiliary tumors. PVE is applied mainly to increase the safety of major hepatic resection in patients with hilar cholangiocarcinoma, HCC, or metastatic liver tumors. Hepatic arterial embolization causes selective ischemia of the liver tumor and enhances the cytotoxicity of the chemotherapeutic agent administered concomitantly. A survival benefit of TACE in patients with unresectable or recurrent HCC has been demonstrated. The significance of preoperative TACE is still controversial. TACE is routinely performed before PVE in HCC patients.

Comparison of long-term effects between intra-arterially delivered ethanol and Gelfoam for the treatment of severe arterioportal shunt in patients with hepatocellular carcinoma

AIM: To evaluate long-term effect of ethanol embolization for the treatment of hepatocellular carcinoma (HCC) with severe hepatic arterioportal shunt (APS), compared with Gelfoam embolization.

METHODS: Sixty-four patients (ethanol group) and 33 patients (Gelfoam group) with HCC and APS were respectively treated with ethanol and Gelfoam for APS before the routine interventional treatment for the tumor. Frequency of recanalization of shunt, complete occlusion of the shunt, side effects, complications, and survival rates were analyzed between the two groups.

RESULTS: The occlusion rate of APS after initial treatment in ethanol group was 70.3%(45/64), and recanalization rate of 1 month after embolization was 17.8%(8/45), and complete occlusion rate was 82.8%(53/64). Those in Gelfoam group were 63.6%(21/33), 85.7%(18/21), and 18.2%(6/33). There were significant differences in recanalization rate and complete occlusion rate between the two groups (P < 0.05). The survival rates in ethanol group were 78% at 6 months, 49% at 12 months, 25% at 24 months, whereas those in Gelfoam group were 58% at 6 months, 23% at 12 months, 15% at 24 months. The ethanol group showed significantly better survival than Gelfoam group (P < 0.05). In the ethanol group, there was a significant prolongation of survival in patients with monofocal HCC (P < 0.05) and Child class A (P < 0.05). There were no significant differences in survival rate in the Gelfoam group with regard to the number of tumor and Child class (P > 0.05). The incidence rate of abdominal pain during procedure in ethanol group was 82.8%. There was no significant difference in postembolization syndromes between two groups. Procedure-related hepatic failure did not occur in ethanol group.

CONCLUSION: Ethanol embolization for patients with HCC and severe APS is efficacious and safe, and may contribute to prolongation of the life span versus Gelfoam embolization.

Modelo de indução de necrose focal hepática: estudo experimental em ratos

OBJETIVO: Investigar a área de necrose focal induzida pela injeção intra-hepática de quatro diferentes substâncias no fígado de ratos. MÉTODOS: Foram utilizados 25 ratos Wistar, com peso variando entre 200 a 250 g, distribuidos em 5 grupos, que receberam 0,1cc das seguintes substâncias: Grupo I (Gr. I) - soro fisiológico a 0,9% (controle). Grupo II (Gr. II) - glicose hipertônica a 50%. Grupo III (Gr. III) - NaCl a 20%. Grupo IV (Gr. IV) - formol a 10%. Grupo V (Gr. V) - etanol. Os animais foram submetidos a laparotomia para que a punção fosse realizada no lobo hepático médio sob visão direta. Todos os animais foram sacrificados após 24 horas da injeção.. Os fígados foram avaliados histologicamente, com o intuito de mensurar a área do tecido necrótico. RESULTADOS: Nos cinco grupos estudados observou-se: Gr. I - 2829mm² (controle); Gr. II - 3805mm² (glicose hipertônica); Gr. III - 3930mm² (NaCl); Gr. IV - 4532mm² (formol) e Gr. V - 6432mm² (etanol). A análise estatística destes valores foi feita pelo método das comparações múltiplas. CONCLUSÃO: 1. O soro fisiológico foi à substância que causou a menor área de necrose (P< 0,05). 2. O NaCl a 20% e a glicose hipertônica a 50% produzem efeitos semelhantes (P > 0,05). 3. O formol a 10% produziu necrose mais extensa que a glicose hipertônica a 50% (P < 0,05) e que o NaCl a 20%, porém não apresentou diferença estatisticamente significativa com esta última (P > 0,05). 4. O etanol foi à substância que, comparada com as outras, mais necrose produziu (P < 0,05).

New considerations for an overall approach to treat hepatocellular carcinoma in cirrhotic patients

BACKGROUND

Increasing numbers of cases and organ shortage justify reconsidering the global therapeutic approach for hepatocelluar carcinoma in cirrhotic patients.

METHODS

Recent literature was reviewed, focused on new therapeutic technologies such as radiofrequency.

RESULTS

For small tumors, liver transplantation offers theoretically the best chance for cure. However, organ shortage may eliminate this advantage, because of tumor progression while waiting for a graft. For small tumors, arising on compensated cirrhosis, resection or radiofrequency ablation may provide efficient local tumor control without precluding subsequent transplantation in case of tumor recurrence and/or cirrhosis decompensation.

CONCLUSIONS

For small tumors and compensated cirrhosis, resection or radiofrequency could represent acceptable first line treatments. In addition to permit safe and immediate tumor control, this strategy would allow a preferential redistribution of grafts to patients with decompensated cirrhosis in whom transplantation is the only possibility.

Preoperative portal vein embolization with a new liquid embolic agent

PURPOSE

To evaluate the effectiveness and safety of a new liquid embolic agent in preoperative portal vein embolization.

MATERIALS AND METHODS

Embol-78 was obtained by means of hydrolysis of polyvinyl acetate and was dissolved in a mixture of ethanol and nonionic water-soluble contrast medium. After percutaneous puncture of the portal vein, embolization of the right portal vein was performed in 22 patients with hepatocellular carcinoma and in 29 patients with nonhepatocellular carcinoma. In each group, changes in volume of the future liver remnant, portal venous pressure, and liver enzymes were evaluated both before and after embolization. Complications were also evaluated.

RESULTS

Portal vein embolization was successful in all patients, without major complications. The mean volumes of the future liver remnant before and 2 weeks after embolization were 385 mL +/- 138 and 533 mL +/- 140, respectively, in the hepatocellular carcinoma group and 517 mL +/- 348 and 755 mL +/- 197, respectively, in the nonhepatocellular carcinoma group. There were only transient elevations in liver enzyme levels after embolization. Mean portal venous pressures before and after the procedure were 16.7 mm Hg +/- 3.8 and 20.3 mm Hg +/- 3.6, respectively, in the hepatocellular carcinoma group and 11.7 mm Hg +/- 3.5 and 14.6 mm Hg +/- 3.6, respectively, in the nonhepatocellular carcinoma group. In each group, changes in volume of the future liver remnant and portal venous pressure were statistically significant (P <.001).

CONCLUSION

The liquid embolic material Embol-78 seems to be effective and safe for preoperative portal vein embolization.

Biliary bile acid concentration is a simple and reliable indicator for liver function after hepatobiliary resection for biliary cancer

BACKGROUND

The functional recovery of the remnant liver after an extended hepatectomy is critical for the outcome of the patient. The aim of this prospective study was to examine whether biliary bile acids could be an indicator for postoperative liver function.

METHODS

Externally drained bile samples were obtained from 51 patients with biliary or periampullary carcinomas before and after surgery. Patients were categorized into 3 groups: group A, 29 hepatectomized patients without liver failure; group B, 7 hepatectomized patients with liver failure (maximum serum bilirubin level, >10 mg/dL); and group C, 15 patients who underwent biliopancreatic resection without hepatectomy, with a good postoperative course. Bile samples were withdrawn 1 day before surgery and on postoperative days 1, 2, 3, 4, 6, and 7. Total bile acids were measured with a 3 alpha-hydroxysteroid dehydrogenase method.

RESULTS

Before surgery, the concentration of bile acids was higher in groups A and C than in group B, and correlated significantly with the indocyamine green disappearance rate (KICG) values (R(2) = 0.557; P <.0001). After surgery, bile acid concentrations decreased in all 3 groups until postoperative day 2, which was followed by a gradual increase. The concentration recovered to the preoperative level in groups A and C but remained low in group B. Biliary bile acid concentrations on day 2 correlated significantly with remnant liver KICG values (R(2) = 0.257; P =.0019). Among several parameters studied, including KICG, remnant liver KICG, biliary bile acids, and biliary bilirubin, biliary bile acid concentration had the most predictive power for occurrence of postoperative liver failure.

CONCLUSION

Biliary bile acid concentration could be a simple, real-time, reliable indicator of preoperative and postoperative liver function.

Portal vein embolization with polyvinyl alcohol particles and coils in preparation for major liver resection for hepatobiliary malignancy: safety and effectiveness--study in 26 patients

PURPOSE

To evaluate whether preoperative portal vein embolization (PVE) with polyvinyl alcohol (PVA) particles and coils is safe and effective for inducing lobar hypertrophy in patients with hepatobiliary malignancy.

MATERIALS AND METHODS

PVE was performed in 26 patients. All patients had malignancy: metastases (n = 11), cholangiocarcinoma (n = 9), hepatocellular carcinoma (n = 5), and gallbladder carcinoma (n = 1). One patient had underlying liver disease caused by hepatitis. PVE was performed if the future liver remnant (FLR) was estimated to be less than 25% of the total liver volume. PVE was performed with a percutaneous transhepatic approach (right, 25 patients; left, one patient). PVA particles and coils were used to occlude the right portal system and veins supplying segment IV to promote FLR hypertrophy (segments I-III +/- IV). FLR hypertrophy was assessed with comparison of computed tomographic scans obtained before and 2-4 weeks after PVE. Effectiveness evaluation was based on changes in absolute FLR size and ratio of FLR to total estimated liver volume (TELV). Safety of PVE and hepatic resection was determined with postprocedure complication rate and median hospital stay.

RESULTS

Sixteen patients underwent hepatic resection (right trisegmentectomy [n = 13], right lobectomy [n = 3]) without mortality. Ten patients did not undergo resection (complete remission after medical therapy [n = 1], lack of regeneration [n = 2], extrahepatic disease undetected prior to PVE [n = 7]). Six patients had biliary obstruction; five were treated percutaneously before PVE. No patient developed postembolization syndrome or signs of fulminant hepatic insufficiency after PVE or resection. Two patients had complications after PVE that did not preclude successful resection. Median hospital stays were 1 day (PVE) and 7 days (liver resection). Mean absolute FLR increased from 325.0 to 458.6 cm3 (increase, 41.1%). Mean TELV was 1,784.8 cm3. FLR/TELV ratio increase was 8%.

CONCLUSION

Preoperative PVE with PVA particles and coils is safe and effective for inducing lobar hypertrophy in patients with advanced hepatobiliary malignancy.

Portal vein embolization before right hepatectomy: prospective clinical trial

OBJECTIVE

To assess the impact of liver hypertrophy of the future liver remnant volume (FLR) induced by preoperative portal vein embolization (PVE) on the immediate postoperative complications after a standardized major liver resection.

SUMMARY BACKGROUND DATA

PVE is usually indicated when FLR is estimated to be too small for major liver resection. However, few data exist regarding the exact quantification of sufficient minimal functional hepatic volume required to avoid postoperative complications in both patients with or without chronic liver disease.

METHODS

All consecutive patients in whom an elective right hepatectomy was feasible and who fulfilled the inclusion and exclusion criteria between 1998 and 2000 were assigned to have alternatively either immediate surgery or surgery after PVE. Among 55 patients (25 liver metastases, 2 cholangiocarcinoma, and 28 hepatocellular carcinoma), 28 underwent right hepatectomy after PVE and 27 underwent immediate surgery. Twenty-eight patients had chronic liver disease. FLR and estimated rate of functional future liver remnant (%FFLR) volumes were assessed by computed tomography.

RESULTS

The mean increase of FLR and %FFLR 4 to 8 weeks after PVE were respectively 44 +/- 19% and 16 +/- 7% for patients with normal liver and 35 +/- 28% and 9 +/- 3% for those with chronic liver disease. All patients with normal liver and 86% with chronic liver disease experienced hypertrophy after PVE. The postoperative course of patients with normal liver who underwent PVE before right hepatectomy was similar to those with immediate surgery. In contrast, PVE in patients with chronic liver disease significantly decreased the incidence of postoperative complications as well as the intensive care unit stay and total hospital stay after right hepatectomy.

CONCLUSIONS

Before elective right hepatectomy, the hypertrophy of FLR induced by PVE had no beneficial effect on the postoperative course in patients with normal liver. In contrast, in patients with chronic liver disease, the hypertrophy of the FLR induced by PVE decreased significantly the rate of postoperative complications.

Portal vein embolization before right hepatectomy: prospective clinical trial

OBJECTIVE

To assess the impact of liver hypertrophy of the future liver remnant volume (FLR) induced by preoperative portal vein embolization (PVE) on the immediate postoperative complications after a standardized major liver resection.

SUMMARY BACKGROUND DATA

PVE is usually indicated when FLR is estimated to be too small for major liver resection. However, few data exist regarding the exact quantification of sufficient minimal functional hepatic volume required to avoid postoperative complications in both patients with or without chronic liver disease.

METHODS

All consecutive patients in whom an elective right hepatectomy was feasible and who fulfilled the inclusion and exclusion criteria between 1998 and 2000 were assigned to have alternatively either immediate surgery or surgery after PVE. Among 55 patients (25 liver metastases, 2 cholangiocarcinoma, and 28 hepatocellular carcinoma), 28 underwent right hepatectomy after PVE and 27 underwent immediate surgery. Twenty-eight patients had chronic liver disease. FLR and estimated rate of functional future liver remnant (%FFLR) volumes were assessed by computed tomography.

RESULTS

The mean increase of FLR and %FFLR 4 to 8 weeks after PVE were respectively 44 +/- 19% and 16 +/- 7% for patients with normal liver and 35 +/- 28% and 9 +/- 3% for those with chronic liver disease. All patients with normal liver and 86% with chronic liver disease experienced hypertrophy after PVE. The postoperative course of patients with normal liver who underwent PVE before right hepatectomy was similar to those with immediate surgery. In contrast, PVE in patients with chronic liver disease significantly decreased the incidence of postoperative complications as well as the intensive care unit stay and total hospital stay after right hepatectomy.

CONCLUSIONS

Before elective right hepatectomy, the hypertrophy of FLR induced by PVE had no beneficial effect on the postoperative course in patients with normal liver. In contrast, in patients with chronic liver disease, the hypertrophy of the FLR induced by PVE decreased significantly the rate of postoperative complications.

Complications of percutaneous transhepatic portal vein embolization

PURPOSE

Percutaneous transhepatic portal vein (PV) embolization (PTPE) is a useful preoperative procedure for extended liver resection. The purpose of the present study was to assess the frequency of technical complications of PTPE and to discuss the risks of this procedure.

MATERIALS AND METHODS

PTPE was performed in 46 patients. Forty-seven procedures were performed because an initial puncture failure required that the procedure be performed twice in one patient. The technical success rate and technical complications were assessed. Complications were analyzed with regard to approach methods and puncture sites. Approach methods were categorized as contralateral or ipsilateral. Puncture sites were categorized into anterior, posterior, and lateral segments. The results were compared statistically with use of the Fisher exact test.

RESULTS

Technical success was achieved in 45 of 47 procedures (95.7%). Complications occurred in seven of 47 procedures (14.9%), including pneumothorax in two, subcapsular hematoma in two, arterial puncture in one, pseudoaneurysm in one, hemobilia in one, and PV thrombosis in one. Subcapsular hematoma and pseudoaneurysm occurred in the same procedure. No patient died as a result of complications. There was no significant difference between the contralateral and ipsilateral approaches. The incidence of complications was significantly higher in procedures involving puncture of the posterior segment than in those involving puncture of the anterior segment (P =.0374).

CONCLUSION

In cases in which the anterior segment cannot be visualized for puncture, PTPE via the lateral segment or transileocolic portal embolization should be considered rather than PTPE via the posterior segment.

Indications for and limitations of portal vein embolization before major hepatic resection for hepatobiliary malignancy

Portal vein embolization is a promising adjunctive tool in liver surgery; however, the understanding of liver regeneration and PVE is still in its infancy. Refinement in patient selection criteria and methods to evaluate hepatic hypertrophy and function should increase the potential indications for PVE and expand the field of major liver surgery.

Transhepatic portal vein embolization: anatomy, indications, and technical considerations

Portal vein embolization (PVE) is increasingly being accepted as a useful procedure in the preoperative treatment of patients selected for major hepatic resection. PVE is performed via either the percutaneous transhepatic or the transileocolic route and is usually reserved for patients whose future liver remnants are too small to allow resection. It is a safe and effective method for inducing selective hepatic hypertrophy of the nondiseased portion of the liver and may thereby reduce complications and shorten hospital stays after resection. A thorough knowledge of hepatic segmentation and portal venous anatomy is essential before performing PVE. In addition, the indications and contraindications for PVE, the methods for assessing hepatic lobar hypertrophy, the means of determining optimal timing of resection, and the possible complications of PVE need to be fully understood before undertaking the procedure. Technique may vary among operators, and further research is necessary to determine the best embolic agents available and the expected rates of liver regeneration for PVE. Nevertheless, as hepatobiliary surgeons become more experienced at performing extended hepatic resections, PVE may be requested more frequently.

Mechanical stress-dependent secretion of interleukin 6 by endothelial cells after portal vein embolization: clinical and experimental studies

BACKGROUND/AIMS

Interleukin-6 (IL-6) is an essential early signal in liver regeneration, however, little is known about what triggers IL-6 release. Changes in portal hemodynamics after portal vein embolization (PVE) may contribute to IL-6 release, leading to regeneration of non-embolized lobe.

METHODS

In 22 patients who underwent right PVE, the diameters of the left portal branches, liver volumes, and serum concentrations of IL-6, tumor necrosis factor-alpha (TNF-alpha), and hepatocyte growth factor (HGF) were measured. We then studied endothelial cells cultured on an elastic silicone membrane and subjected to continuous uni-axial stretch. Supernatant cytokine concentrations were measured.

RESULTS

The diameters of the portal branches increased by 150% after PVE. Serum IL-6 concentrations increased within 3h after PVE. The concentrations of TNF-alpha and HGF remained unchanged. The left lobe volume increased 2 weeks after PVE. The IL-6 concentrations in the supernatant of endothelial cells with stretch stress were higher than that in the non-stretched control group.

CONCLUSIONS

These findings indicate that PVE dilates the portal branches in the non-embolized lobe, exposing hepatic vasculature to stretch stress. This hemodynamic change may act as a trigger for IL-6 release from endothelial cells and contribute to the activation of regenerative cascade in the non-embolized lobes.

[Portal vein embolization prior to hepatectomy. Techniques, indications and results]

Postoperative liver failure is a severe complication of major hepatectomies, in particular in patients with a chronic underlying liver disease. Preoperative interruption of the portal flow in the liver territories planned to be removed, induces their atrophy and the compensatory hypertrophy of the segments spared by the resection. This interruption can be induced by the surgical ligation of the portal branches or by the percutaneous intraportal injection, under ultrasound guidance, of glues or sclerosing agents. Preoperative portal vein embolisation is usually indicated when the remnant liver accounts for less than 25-40% of the total liver volume. Feasibility is close to 100% and the risk comparable to that of a percutaneous liver biopsy. It is well tolerated and the biological impact is minimal in patients without liver failure. Compensatory hypertrophy of the non-embolised segments is maximal during the first 2 weeks and persists, although to a lesser extent during approximately 6 weeks. The magnitude of hypertrophy is correlated with the volume of parenchyma embolised, and is reduced in diabetic or jaundiced patients or when there is an active chronic liver disease. Liver resection is performed 2 to 6 weeks after embolisation. Retrospective studies and one prospective study suggest that patients so prepared have a reduced perioperative risk and that their long term carcinologic results are not impaired.

Hyperbaric oxygenation after portal vein emobilization for regeneration of the predicted remnant liver

BACKGROUND

Liver failure often develops after extensive liver resection. Preoperative portal vein embolization to induce compensatory hypertrophy in the predicted remnant liver decreases clinical complications after hepatectomy. The aim of this study was to examine whether hyperbaric oxygenation (HBO) after portal vein embolization increases compensatory hypertrophy of the predicted liver remnant. We performed portal vein ligation and HBO in rats to investigate whether HBO after portal vein embolization increases compensatory hypertrophy of the predicted remnant liver.

METHODS

Rats were divided into four groups that underwent (1) laparotomy only (control group); (2) right portal vein ligation (RPL group); (3) RPL followed by HBO at 2 atm (HBO-2 atm group; 1 h/day, 5 days/week for 2 weeks); or (4) RPL followed by HBO at 3 atm (HBO-3 atm group). Laparotomy was repeated after 2 weeks in each group; serum levels of albumin and hepatocyte growth factor (HGF) were measured, and the ratio of the weights of nonligated to ligated hepatic segments and the percentage of hepatocytes expressing proliferating cell nuclear antigen (PCNA) in ligated hepatic segments were determined.

RESULTS

In rats that had received HBO after RPL, serum levels of HGF, weight ratios of nonligated to ligated hepatic segments, and the percentage of PCNA-positive hepatocytes in nonligated liver were significantly higher than those in the control group. Furthermore, rats that had undergone 3-atm HBO after RPL had significantly higher serum levels of HGF and percentages of PCNA-positive hepatocytes in nonligated hepatic segments.

CONCLUSIONS

Preoperative HBO after portal vein embolization may be useful for inducing compensatory hypertrophy of the predicted remnant liver.

Portal vein embolization with use of polyvinyl alcohol particles

Preoperative portal vein embolization has been used as method of inducing compensatory hypertrophy in the future remnant liver since it was first described in the late 1980s. Many different vascular embolic agents have been successfully used for this procedure, and there is no general consensus regarding which is the best agent. Polyvinyl alcohol (PVA) particles commonly used for arterial embolization come in many sizes, are readily available, and are easy to administer via conventional catheters. We describe an easy, safe, and effective method of the use of PVA particles for portal vein embolization.

Portal vein embolization: rationale, technique and future prospects

BACKGROUND

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.

METHODS

A Medline search was performed to identify papers reporting the use of PVE before hepatic resection. Techniques, complications and results are reviewed.

RESULTS

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.

CONCLUSION

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.