Liver resection combined with inferior vena cava resection and reconstruction using artificial vascular graft: A literature review

Abstract In cases where liver tumors invade the inferior vena cava (IVC), IVC resection along with liver resection may be needed to effect a cure. Furthermore, if the IVC defect is large, IVC reconstruction with vascular graft after resection is required. There are limited reports of cases of IVC reconstruction using a graft. By reviewing data from the literature of previous studies, the present study was aimed at investigating the surgical outcomes of liver resection with IVC resection and reconstruction using an artificial vascular graft. PubMed was searched for previous articles reporting cases with the combined surgery. The search was limited to articles in English, and cases with exceptional surgeries such as in situ cold perfusion, and ante situm and ex vivo techniques were excluded from this study. Surgical outcomes of the extracted cases were investigated. Cases dealt only with primary closure after IVC resection, and those in which the IVC tumor thrombus was treated by opening the IVC wall, removing the thrombus and then closing the IVC without wall excision were not included in this study. The literature search identified 13 studies, including 111 cases. Operative mortality in the reported cases was 8.1% (9 out of 111 cases). Thrombus in the artificial vascular graft was observed in two cases, and patency of the graft during the follow‐up period was confirmed in 109 of the 111 cases (98.2%). These results suggested that the surgical outcomes of liver resection combined with IVC resection and reconstruction using the artificial vascular graft were favorable.


| RESULTS
Through the literature search, no systemic reviews were found and there were 13 study articles that met the inclusion criteria (Figure 1). 1,2,[4][5][6][7][8][9][10][11][12][13][14][15][16] The 13 studies are summarized in Table 1 and included 111 cases. Median number of cases in each study was four (range = 3-33). The liver tumor to be resected at surgery in the 111 cases was as follows: HCC in 12 cases, ICC in 26 cases, LM in 19 cases, and others in 18 cases. Others included other liver tumors such as sarcoma and direct invasion to the liver from other organs.
In a particular study, 15 the liver tumor in 33 cases was diagnosed as HCC, ICC, LM or others, but distribution of the disease was unknown. In another report, the disease of three cases was not described. 8 In the searched studies, the surgical procedure was selected based on the extent of the tumor and residual liver function. Type of resection and repair was determined based on IVC involvement; when the involvement was small, IVC was reconstructed by primary repair or with a patch. For the patch, an artificial vascular graft, the expanded polytetrafluoroethylene (ePTFE) graft (Gore-Tex; WL Gore & Associates, Inc., Flagstaff, AZ, USA), or bovine or horse pericardium were used. This review did not include cases with pericardium for patch repair. For a larger degree of IVC involvement, the entire circumference of the IVC was replaced with an artificial vascular graft. As the artificial vascular graft for the circumferential replacement of IVC, although Dacron graft (Hemashield; Meadox Medicals, Inc., Oakland, NJ, USA) was used in limited cases, ePTFE graft was used in most cases. There were two patterns of clamping reported based on the extent and location of IVC tumor involvement ( Figure 2). The first pattern of clamping (pattern 1) was used in cases where IVC involvement with the tumor was located below the root of the hepatic veins and placement of the IVC clamp below the hepatic veins was allowed. In these cases, the IVC was clamped at the F I G U R E 1 Flowchart representing the selection of articles for the present study. The search was carried out using specific terms with PubMed. The 324 searched articles were first screened by title and abstract of the articles. Then, the remaining 132 potentially relevant articles were further assessed for their relevance. Finally, 13 articles were selected for this study TOMIMARU ET AL. IVC resection and grafting was carried out while these clamps were in place. The second pattern (pattern 2) reported was adopted in cases where tumor involvement of the IVC did not allow for placement of the IVC clamp below the hepatic veins as a result of involvement with the tumor. In these cases, in addition to the clamp below the IVC wall involved with the tumor, the IVC above the root of the hepatic veins and the hepatoduodenal ligament were clamped, which is known as total hepatic vascular exclusion (THVE). 17,18 T A B L E 1 Reports of cases from previous studies of liver resection combined with IVC resection and reconstruction using artificial vascular graft F I G U R E 2 Patterns of clamping for inferior vena cava (IVC) resection and reconstruction. There were two patterns of clamping for IVC resection and reconstruction based on IVC involvement, as shown in these representative intraoperative images following right hemihepatectomy. Pattern 1 was adopted in cases where IVC involvement was located below the root of the hepatic veins, allowing for placement of the IVC clamp below the hepatic veins. In this pattern, clamp placement was below the IVC wall involved with the tumor (A), and on the IVC below the root of the hepatic veins (B). Pattern 2 was adopted in cases where the IVC clamp below the hepatic veins was not possible as a result of tumor involvement. The total hepatic vascular exclusion (THVE) technique was used for the clamp in these cases, with clamping of the hepatoduodenal ligament (A), the IVC below the IVC wall involved with the tumor (B), and the IVC above the root of the hepatic veins (C). The clamp above the root of the hepatic veins was repositioned below the root of the hepatic veins (D) for unclamping of the hepatoduodenal ligament for restoration of perfusion to the liver after the anastomosis of the cranial IVC side During THVE, the IVC was resected and reconstructed. After the reconstruction, the clamp above the root of the hepatic veins was The second problem is the necessity for antithrombotic therapy after the reconstruction. In more than half of the previous studies, antithrombotic therapy was given after the reconstruction, but no clear criteria for giving antithrombotic therapy were commented upon in each study. Antithrombotic therapy was carried out mainly by using heparin, although there were several cases where nafamostat mesilate was used with heparin, and those where aspirin was used after the heparin dose. This prevalence of antithrombotic therapy might be as a result of a study showing that, in two cases where thrombus was identified in the graft, antithrombotic therapy had been discontinued. However, necessity for antithrombotic therapy after the reconstruction has not been examined in previous studies with high level evidence such as prospective studies comparing outcomes between cases with and without antithrombotic therapy. Furthermore, this concern should be discussed considering also the abovementioned necessity for IVC reconstruction after the resection.
Thus, this problem seems complicated, although it will ideally be solved in the future. Last, there have been other proposed procedures such as in situ cold perfusion, 4,15,22,23 and ante situm, 4,24,25 and ex vivo techniques. 4,15,22,23 For example, the ex vivo technique interrupts and transects major inflow and outflow of the liver, as well as the bile duct, and removes the liver from the abdomen. On a back table, the liver remains under cold perfusion while tumor resection is carried out, followed by reimplantation. 15 These procedures TOMIMARU ET AL.

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are effective for patients where obtaining tumor-free margins, in situ, is not possible, but they are technically demanding complicated procedures and associated with high surgical stress and operative risks. Therefore, their indication should be strictly determined.
In summary, surgical outcomes of liver resection combined with IVC resection and reconstruction using an artificial vascular graft were investigated based on a literature review of previous studies.
The results of the investigation showed that the outcomes were favorable, suggesting feasibility of the combined surgery.

DISCLOSURE
Conflicts of interest: Authors declare no conflicts of interest for this article.
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