Preoperative Portal Vein Embolization Tailored to Prepare the Liver for Complex Resections: Initial Experience

Ethylene vinyl alcohol copolymer for occlusion of specific portal branches during preoperative portal vein embolisation with n-butyl-cyanoacrylate

OBJECTIVES

To evaluate the safety and efficacy of ethylene vinyl alcohol copolymer (EVOH) injection for selective occlusion of portal branches considered at risk for non-target embolisation during preoperative portal vein embolisation (PVE).

METHODS

Twenty-nine patients (mean age, 57 ± 17 years) submitted to PVE with n-butyl-cyanoacrylate (NBCA) and additional EVOH for selected portal branches were retrospectively analysed. Indications for the use of EVOH and the selected portal branches were evaluated. Degree of hypertrophy of the future liver remnant (FLR) and kinetic growth were assessed by CT volumetry performed before and 3-6 weeks after PVE. Clinical outcome and histopathological analysis of portal veins occluded with EVOH were reviewed.

RESULTS

EVOH was indicated intraoperatively for embolisation of selected portal branches that the operator reported at risk to provoke non-target embolisation with NBCA. Indications for the use of EVOH were embolisation of segment IV (n = 21), embolisation of segmental portal branches with early bifurcation (n = 7) and PVE in a 1-year-old girl with cystic hamartomas. All targeted portal branches were successfully embolised. There were no cases with non-target embolisation by EVOH. The degree of hypertrophy of the FLR was 14.3 ± 8.1% and the kinetic growth rate was 2.7 ± 1.8% per week.

CONCLUSION

EVOH is safe and effective for embolisation of selected portal vein branches considered at risk for non-target embolisation.

KEY POINTS

• EVOH is another effective liquid embolic agent for preoperative PVE. • EVOH is relatively simple to handle with a minimal risk of non-target embolisation. • During PVE, some portal branches considered complicated to occlude with NBCA may be efficiently embolised with EVOH.

Portal Vein Embolization in the Setting of Staged Hepatectomy with Preservation of Segment IV ± I Only for Bilobar Colorectal Liver Metastases: Safety, Efficacy, and Clinical Outcomes

PURPOSE

To assess frequency of adverse events, efficacy, and clinical outcomes of percutaneous portal vein embolization (PVE) in patients with bilobar colorectal liver metastases undergoing staged hepatectomy with preservation of segment IV ± I only.

MATERIALS AND METHODS

Retrospective analysis was performed of 40 consecutive patients who underwent right PVE after successful left lobectomy between 2005 and 2013. Rates of adverse events, future liver remnant (FLR) > 30% compared with baseline liver volume, clinical success (completion of staged hepatectomy with clearance of liver metastases), and overall survival were analyzed.

RESULTS

PVE was performed using polyvinyl alcohol particles (n = 7; 17.5%), particles plus coils (n = 23; 57.5%), and N-butyl cyanoacrylate glue plus ethiodized oil (n = 10; 25%). Technical success was 100%. After PVE, 20% (n = 8) of patients exhibited portal venous thrombosis, ranging from isolated intrahepatic portal branch thrombosis to massive thrombosis of the main portal vein (n = 3) and responsible for periportal cavernoma and portal hypertension in 5 patients. Of patients, 23 (57.5%) had FLR ≥ 30%, and 21 (52.5%) had clinical success. Six patients had significant stenosis or occlusion of the left portal vein or biliary system after original left lobectomy, which was independently associated with FLR < 30% (R² = 0.24). Clinical success was the only independent variable associated with survival (R² = 0.25).

CONCLUSIONS

PVE for staged hepatectomy with preservation of segment IV ± I only is technically feasible, leading to adequate hypertrophy and clinical success rates in these patients with poor oncologic prognosis. Portal venous thrombosis is greater after the procedure than in the setting of standard PVE.

Liver angulometry: a simple method to estimate liver volume and ratios

OBJECTIVES

Volumetry is standard method for evaluating the volumes of the right liver (RL), left liver (LL), left lateral segments (LLS), total liver (TL) and future liver remnant (FLR). The aim of this study was to report a simple technique based on measurements of liver angles (angulometry) that can be used to predict liver ratios.

METHODS

Fifty computed tomography (CT) scans obtained in subjects with normal liver were studied. Four CT scan levels were preselected: level 1 passed by the upper part of the hepatic veins; level 2 passed by the left portal vein branch division; level 3 passed by the right portal vein branch division, and level 4 passed by the gallbladder bed. Left and right tangent lines passing the liver edges were drawn and joined to the centre of the vertebra defining the TL angle. Two lines through, respectively, the plane of the middle hepatic vein and the left portal branches determined the angles of the RL, LL and LLS. Volumetric and angulometric data obtained on levels 2 and 3 in 50 different subjects were compared.

RESULTS

Level 2 CT scans represented the most accurate way of obtaining angulometric measurements. The mean ± standard deviation (SD) angles of the TL and LL were 134 ± 12 ° and 55 ± 12 °, respectively. The mean ± SD percentages of the TL represented by the LL in angulometry and volumetry were 38 ± 7% and 36 ± 6%, respectively (non-significant difference). The mean ± SD percentages of the TL represented by the LLS in angulometry and volumetry were 25 ± 4% and 20 ± 3%, respectively (P < 0.05). The mean ± SD overestimation of the percentage of the TL represented by the LLS in angulometry was 2.7 ± 7.0%.

CONCLUSIONS

Angulometry is a simple and accurate technique that can be used to estimate the ratio of the FLR to TL volume on one or two CT (or magnetic resonance imaging) slices. It can be helpful for clinicians, especially before right or extended right hepatectomy and after right portal vein occlusion techniques.

Operative terminology and post-operative management approaches applied to hepatic surgery: Trainee perspectives

Outcomes in hepatic resectional surgery (HRS) have improved as a result of advances in the understanding of hepatic anatomy, improved surgical techniques, and enhanced peri-operative management. Patients are generally cared for in specialist higher-level ward settings with multidisciplinary input during the initial post-operative period, however, greater acceptance and understanding of HRS has meant that care is transferred, usually after 24-48 h, to a standard ward environment. Surgical trainees will be presented with such patients either electively as part of a hepatobiliary firm or whilst covering the service on-call, and it is therefore important to acknowledge the key points in managing HRS patients. Understanding the applied anatomy of the liver is the key to determining the extent of resection to be undertaken. Increasingly, enhanced patient pathways exist in the post-operative setting requiring focus on the delivery of high quality analgesia, careful fluid balance, nutrition and thromboprophlaxis. Complications can occur including liver, renal and respiratory failure, hemorrhage, and sepsis, all of which require prompt recognition and management. We provide an overview of the relevant terminology applied to hepatic surgery, an approach to the post-operative management, and an aid to developing an awareness of complications so as to facilitate better confidence in this complex subgroup of general surgical patients.

Interventional oncologic approaches to liver metastases

Metastatic liver disease is the most common cause of death in cancer patients. Complete surgical resection is currently considered the only curative treatment, with only about 25% of patients being amenable to surgery. Therefore, a variety of interventional oncologic techniques have been developed for treating secondary liver malignancies. The aim of these therapies is either to allow patients with unresectable tumors to become surgical candidates, provide curative treatment options in nonsurgical candidates, or improve survival in a palliative or even curative approach. Among these interventional therapies are transcatheter therapies such as portal vein embolization, hepatic artery infusion chemotherapy, transarterial chemoembolization, and radioembolization, as well as interstitial techniques, particularly radiofrequency ablation as the most commonly applied technique. The rationale, application and clinical results of each of these techniques are reviewed on the basis of the current literature. Future prospects such as gene therapy and immunotherapy are introduced.