Comparative study of portal vein embolization versus portal vein ligation for induction of hypertrophy of the future liver remnant using a mini-pig model

Preoperative portal vein embolization (PVE) for patients with hepatocellular carcinoma can improve resectability and may improve disease-free survival

BACKGROUND

The aim of this study is to identify the efficacy of portal vein embolization (PVE) before right hepatectomy in patients with hepatocellular carcinoma (HCC) with regard to hepatic function, surgical stress, and survival benefit.

METHODS

Fifty-five patients with HCC underwent right hepatectomy between 1999 and 2009. Preoperative PVE was performed in 19 patients (PVE group) and was not applied in 36 patients (non-PVE group). Changes in liver function and volume were investigated in PVE group. Short and long clinical outcomes after the surgeries were compared between the two groups.

RESULTS

The percentage of future liver remnant (%FLR) before PVE was significantly lower (37.8%) in PVE group than in non-PVE group (58.1%) but increased remarkably after PVE (from 37.8% to 55.0%, P < 0.0001). Cumulative disease-free survival and overall survival rates in PVE group were significantly superior to those in non-PVE group (P = 0.010 and 0.049, respectively). Although surgical stress estimated by E-PASS scores and CRP value was not different between the groups, the postoperative value of PT on postoperative day 3 in PVE group was significantly better than in non-PVE group.

CONCLUSIONS

Preoperative PVE improves resectability and may improve disease-free survival for patients with HCC requiring right hepatectomy.

Portal vein embolization (prior to major hepatectomy) effects on regeneration, resectability, and outcome

Portal vein embolization (PVE) is used to increase the volume and function of the liver that will remain after extensive liver resection. Operative outcomes are improved in properly selected patients who undergo PVE and experience adequate future liver remnant (FLR) hypertrophy. Absolute volume and volume change of the FLR after PVE (interpreted in context of liver disease) predict adequate liver function postresection. Oncologic outcomes following resection in patients with appropriately applied PVE are excellent.

Selective portal vein ligation and embolization induce different tumoral responses in the rat liver

BACKGROUND

Portal vein ligation (PVL) and portal vein embolization (PVE) are used to enhance liver volume before hepatectomy for colorectal liver metastasis (LM). Impact of such techniques on tumor growth is not well known. This experimental study aimed to assess impact of PVE and PVL on LM growth in a murine model of colorectal LM.

METHODS

Single macroscopic tumor was induced by injection of 0.5 × 10(6) DHD/K12 cells under the liver capsule of BDIX rats at day 0. Multiple microscopic tumors were obtained by intra-portal injection of 1 × 10(6) cells at day 7. At day 8, rats were divided in 3 groups: PVE group (selective 70% PVE), PVL group (selective 70% PVL); control group (sham laparotomy). Rats were sacrificed at day 37 (11 in PVE, 12 in PVL, and 10 rats in control groups). Liver volume and LM volumes were assessed.

RESULTS

Nonoccluded liver volume was larger in the PVE and PVL groups vs control group (P < .0001 and P < .0001, respectively) but showed no difference in PVE vs PVL groups (P = .08). LM volume in the occluded liver was smaller in the PVE vs control groups (P = .006) and larger in the PVL vs control groups (P = .001). LM volume in the nonoccluded liver was larger in the PVE and PVL groups vs control group (P = .010 and P = .010, respectively) but showed no difference in PVE vs PVL groups (P= .878).

CONCLUSION

Both PVL and PVE modify tumor growth, especially in nonoccluded lobe. These results could be of clinical importance in humans where both techniques are widely used.

Efficient hepatocyte engraftment and long-term transgene expression after reversible portal embolization in nonhuman primates

The feasibility of ex vivo gene therapy as an alternative to liver transplantation for the treatment of liver metabolic diseases needs to be analyzed in large animal models. This approach requires appropriate gene transfer vectors and effective hepatocyte engraftment. Lentiviral vectors have the ability to transduce nondividing differentiated cells, such as hepatocytes, and portal vein occlusion increases hepatocyte engraftment. We investigated whether reversible portal vein embolization combined with ex vivo lentivirus-mediated gene transfer is an effective approach for successful hepatocyte engraftment in nonhuman primates and whether the transgene remains expressed in the long term in transplanted hepatocytes in situ. Simian hepatocytes were isolated after left lobe resection, and the left and right anterior portal branches of animals were embolized with absorbable material. Isolated hepatocytes were labeled with Hoechst dye or transduced in suspension with lentiviruses expressing green fluorescent protein under the control of the human apolipoprotein A-II promoter and transplanted via the inferior mesenteric vein. The whole procedure was well tolerated. The embolized liver was revascularized within 2 weeks. The volume of nonembolized liver increased from 38.7% +/- 0.8% before embolization to 55.9% +/- 1% after embolization and hepatocytes significantly proliferated (10.5% +/- 0.4% on day 3 after embolization). Liver repopulation after transplantation with Hoechst-labeled hepatocytes was 7.4% +/- 1.2%. Liver repopulation was 2.1% +/- 0.2% with transduced hepatocytes, a proportion similar to that obtained with Hoechst-labeled cells, given that the mean transduction efficacy of simian hepatocyte population was 34%. Transgene expression persisted at 16 weeks after transplantation.

CONCLUSION

We have developed a new approach to improve hepatocyte engraftment and to express a transgene in the long term in nonhuman primates. This strategy could be suitable for clinical applications.

Portal vein embolization using a nitinol plug (Amplatzer vascular plug) in combination with histoacryl glue and iodinized oil: adequate hypertrophy with a reduced risk of nontarget embolization

The purpose of this study was to assess whether portal vein embolization (PVE) using a nitinol vascular plug in combination with histoacryl glue and iodinized oil minimizes the risk of nontarget embolization while obtaining good levels of future liver remnant (FLR) hypertrophy. Between November 2005 and August 2008, 16 patients (8 females, 8 males; mean age, 63 +/- 3.6 years), each with a small FLR, underwent right ipsilateral transhepatic PVE prior to major hepatectomy. Proximal PVE was initially performed by placement of a nitinol vascular plug, followed by distal embolization using a mixture of histoacryl glue and iodinized oil. Pre- and 6 weeks postprocedural FLR volumes were calculated using computed tomographic imaging. Selection for surgery required an FLR of 0.5% of the patient's body mass. Clinical course and outcome of surgical resection for all patients were recorded. At surgery, the ease of hepatectomy was subjectively assessed in comparison to previous experience following PVE with alternative embolic agents. PVE was successful in all patients. Mean procedure time was 30.4 +/- 2.5 min. Mean absolute increase in FLR volume was 68.9% +/- 12.0% (p = 0.00005). There was no evidence of nontarget embolization during the procedure or on subsequent imaging. Nine patients proceeded to extended hepatectomy. Six patients demonstrated disease progression. One patient did not achieve sufficient hypertrophy in relation to body mass to undergo hepatic resection. At surgery, the hepatobiliary surgeons observed less periportal inflammation compared to previous experience with alternative embolic agents, facilitating dissection at extended hepatectomy. In conclusion, ipsilateral transhepatic PVE using a single nitinol plug in combination with histoacryl glue and iodinized oil simplifies the procedure, offering short procedural times with minimal risk of nontarget embolization. Excellent levels of FLR hypertrophy are achieved enabling safe extended hepatectomy.

Major hepatectomy for colorectal metastases: is preoperative portal occlusion an oncological risk factor?

BACKGROUND

This study investigates oncological risks and benefits of portal occlusion (PO) in major resection for colorectal liver metastases (CLM).

METHODS

Between 1995 and 2004, 107 patients were scheduled for major hepatectomy for CLM. Of these, 53 patients were selected for PO due to insufficient future liver remnant (FLR), and 54 patients had straightforward hepatectomy. Associations of clinicopathologic factors with resectability, and outcome after PO were analyzed.

RESULTS

21 of 53 patients (39.6%) after PO were unresectable. These patients had a significant smaller volume of the FLR than the 32 resected patients after PO (P = .029). In total, 17 patients (80.9%) did not undergo resection due to cancer progression. Among these, 11 patients (52.4%) exhibited either a progression of known metastases located in the occluded lobes, or new metastases in the nonoccluded portion of the liver. In another 4 individuals (19%), the decision against resection resulted from insufficient hypertrophy of the FLR. Following major hepatectomy, the 5-year survival was 43.66%. Although there was a significantly higher rate of extended hepatectomies versus formal hepatectomies (P < .001), more bilobar distributed metastases versus unilobar manifestations (P = .015), and a smaller resection margin (P = .01) in patients who had PO, no adverse effect on mortality, morbidity, recurrence and survival was observed.

CONCLUSION

Unresectability after PO is a major problem that warrants multidisciplinary improvements, and randomization to resection with or without PO remains ethically problematic. However, following adequate patient selection, PO may provide a significant survival benefit for patients with prior unresectable CLM.