Outcome of extra-anatomic vascular reconstruction in orthotopic liver transplantation

Anastomosis selection in liver transplantation for recipients with unusable recipient hepatic arteries: a bayesian network meta-analysis

BACKGROUND

The anastomosis of donor and recipient hepatic arteries is standard in liver transplantations. For transplant recipients with unusable hepatic arteries, appropriate artery selection should be conducted using evidence-based considerations; therefore, this network meta-analysis (NMA) aimed to analyze the most suitable alternative recipient artery for anastomosis during liver transplantations.

METHODS

Comprehensive searches of the Scopus, Cochrane Library, and MEDLINE databases were conducted to analyze observational studies containing non-standard anastomoses in liver transplantations that used the splenic artery, aorta, celiac, or branches of the gastric artery. The outcome parameters included intraoperative components, complications, and survival data. This NMA used the BUGSnet package in R studio and the results were presented in a Forest plot, league table, and SUCRA plot.

RESULTS

Among the 13 studies included in this NMA, 5 arteries were used for the anastomoses. The splenic artery anastomosis showed a high risk of thrombosis and a low risk of stenosis (OR 1.12, 95% CI 0.13-3.14) and biliary tract abnormalities (OR 0.79, 95% CI 0.36-1.55). In addition, the graft survival (OR 1.08; 95% CI 0.96-1.23) and overall survival (1-year survival OR 1.09, 95% CI 0.94-1.26; 5-year survival OR 1.95% CI 0.83-1.22) showed favorable results using this artery. Constraints to the use of the splenic artery were longer operation and cold ischemic times. However, the duration of hospital stay (MD 1.36, 95% CI -7.47 to 10.8) was shorter than that when the other arteries were used, and the need for blood transfusions was minimal (MD -1.74, 95% CI -10.2 to 6.7).

CONCLUSION

In recipients with unusable hepatic arteries, the splenic artery of the patient should be the first consideration for anastomosis selection in liver transplantations.

Liberal Use of Interposition Grafts for Arterial Reconstruction Is Safe and Effective in Adult Split Liver Transplantation

Background.

Split liver transplantation (SLT) addresses donor shortages by providing 2 partial grafts from a single donor liver. Arterial reconstruction using an interposition graft facilitates the use of split grafts with difficult recipient anatomy. Its use, however, remains controversial because of a reported increased risk of complications.

Methods.

A retrospective review of the prospectively maintained Australian National Liver Transplantation Unit database was performed. Donor, recipient, operative, and complications data for adults receiving an SLT between July 2002 and November 2019 were extracted.

Results.

Arterial reconstruction required an interposition graft in 46 of 155 patients. Overall graft and patient survival were not significantly different between the groups with 1-, 3-, and 5-y graft survivals of 82%, 77%, and 69% for those with interposition grafts and 86%, 79%, and 77% for those without interposition grafts, respectively (P = 0.499). There were more cut liver bile leaks in the interposition graft group (26% versus 9%, P = 0.004), but otherwise, no significant differences in the rate of biliary complications (39% versus 29% P = 0.200), hepatic artery thrombosis (7% versus 10%, P = 0.545), or hepatic artery stenosis (13% versus 10%, P = 0.518).

Conclusions.

Liberal use of interposition grafts for arterial reconstruction in SLT is safe and does not result in increased complications.

Addressing the challenges of split liver transplantation through technical advances. A systematic review

BACKGROUND

Split liver transplantation addresses donor shortages by facilitating the transplant of two recipients using one donor liver. Some still consider these grafts inferior due to prolonged cold ischaemia time and at times difficult vascular reconstruction. Techniques such as in-situ splitting, machine perfusion and interposition grafts may address these challenges and thereby address these concerns. The aim of this review is to assess these technical advances in split liver transplantation, their utility and outcomes.

METHODS

A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Keywords included 'split liver transplantation', 'arterial reconstruction', and 'machine perfusion'. Data found was synthesised into sections including: methods of splitting, full-left full-right splitting, donor cholangiography, machine perfusion and arterial reconstruction.

RESULTS

A total of 78 articles met inclusion criteria after screening of 151 eligible articles. These were subdivided into the following categories: in-situ (25), ex-vivo (25), full-left full-right splitting (15), donor cholangiography (2), machine perfusion (6), and arterial reconstruction (5). The in-situ splitting technique reduces the cold ischaemia time compared to the ex-vivo technique which may improve graft quality and liver splitting during normothermic machine perfusion is a novel technique with the potential to incorporate the best aspects of both techniques. Interposition grafts are often required during split liver transplantation but have an increased risk of hepatic artery thrombosis.

CONCLUSION

Advancements in technique have allowed many of the unique challenges of split liver transplantation to be overcome. Overall, this supports the use of split liver transplantation in broader and riskier settings and we advocate for liver transplant surgeons to not hesitate in using these grafts liberally and expanding their recipient selection criteria.

A systematic review and meta-analysis of rescue revascularization with arterial conduits in liver transplantation

Although aortohepatic conduits (AHCs) provide an effective technique for arterialization in liver transplantation (LT) when the native recipient artery is unusable, various publications report higher occlusion rates and impaired outcome compared to conventional anastomoses. This systematic review and meta-analysis investigates the published evidence of outcome and risk of AHCs in LT using bibliographic databases and following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Primary and secondary outcome were artery occlusion as well as graft and patient survival. Twenty-three retrospective studies were identified with a total of 22 113 patients with LT, of whom 1900 patients (9%) received an AHC. An AHC was used in 33% of retransplantations. Early artery occlusion occurred in 7% (3%-16%) of patients with AHCs, compared to 2% (1%-3%) without conduit (OR 3.70; 1.63-8.38; P = .001). The retransplantation rate after occlusion was not significantly different in both groups (OR 1.46; 0.67-3.18; P = .35). Graft (HR 1.38; 1.17-1.63; P < .001) and patient (HR 1.57; 1.12-2.20; P = .009) survival was significantly lower in the AHC compared to the nonconduit group. In contrast, graft survival in retransplantations was comparable (HR 1.00; 0.82-1.22; P = .986). Although AHCs provide an important rescue option, when regular revascularization is not feasible during LT, transplant surgeons should be alert of the potential risk of inferior outcome.

The role of arterial conduits for revascularisation in adult orthotopic liver transplantation

The successful outcome in orthotopic liver transplantation (OLT) is critically dependent on the uncompromised hepatic graft blood inflow. Arterial conduits represent a good solution in cases where conventional revascularisation is not possible. The purpose of this systematic review is to analyse the published evidence on the use of arterial conduits in adult OLT. After review of the Pubmed and EMBASE databases, 19 relevant studies were identified and analysed. Even though patient survival was comparable, most large studies reported worse 1-, 3- and 5-year graft survival rates compared to grafts with standard arterial revascularisation. Primary grafts were more commonly affected than re-grafts. Early and late hepatic artery thrombosis occurred more commonly, while the use of an arterial conduit was identified as an independent risk factor. The overall biliary complications were comparable, however, ischaemic cholangiopathy was encountered about 3 times more in patients with arterial conduits and strongly correlated with the occurrence of late HAT. In conclusion, the use of arterial conduit is a useful option in adult OLT in cases that the conventional revascularisation technique cannot be used or results in suboptimal arterial inflow. More studies directly addressing issues such as pre-operative evaluation regarding the need for arterial conduit, the types of vessels used, positioning of the conduit and post-operative management are required.

Liver-specific deceased donor risk indices

In order to assess the quality of the donor liver, procuring surgeons should accurately evaluate not only general donor risk indices, such as donor age, causes of brain death and cold ischemic time, but also consider the specific donor risk indices. In this review, we focus on liver-specific deceased donor risk indices, including liver steatosis, anti-hepatitis B core (HBc) positive or hepatitis C virus (HCV) positive donors, hypernatremia and anatomical variations. Liver steatosis is strongly associated with poor graft function after liver transplantation. Liver with more than 40-50% macrosteatosis should not be used. However, at present the quantity of fatty livers lack accepted standards. The computerized image analysis programs should be used to automate the determination of fat content in liver biopsy specimens. Liver grafts from anti-HBc positive donors can be safely used, preferentially in hepatitis B surface antigen (HBsAg) positive or anti-HBc/anti-HBs positive recipients. HCV positive allografts free from fibrosis or severe inflammation are a safe option for HCV positive recipients. The procurement team should consider liver biopsy to evaluate these HCV positive allografts. Donor serum sodium over 150 mm may predict a higher rate of graft primary non-functions. Recently, however, some investigators reported the sodium level likely has little clinical impact on post-transplant liver function. The incidence of hepatic artery variations has been reported to be approximately 30%. To avoid injuries, it is very important to know and identify these variations with precision at the time of organ procurement.

Preoperative hepatobiliary imaging: what does the radiologist need to know?

Accurate preoperative reporting is essential in guiding the surgeon in deciding when and how to operate safely and effectively. Critically, this relies on an understanding of the operative issues faced by the surgeon, which is not always appreciated by the radiologist. This paper therefore aims to address this, first focusing on relevant anatomical variants, and then issues specific to laparoscopic cholecystectomy, hepatic transplantation, and finally hepatic resection (including cholangiocarcinoma resection). Throughout the paper, there is an emphasis on associated surgical techniques to add context to the discussion.

Vascular complications following liver transplantation

Vascular complications (stenosis or thrombosis of the hepatic artery, portal vein or hepatic vein) are a relatively common occurrence following liver transplantation. Routine screening with ultrasound is critical to early detection of these complications. Careful application of standard interventional techniques (diagnostic catheter angiography, balloon angioplasty with selective stenting) may be used to confirm the ultrasound findings, treat the underlying lesions, and contribute to long-term graft survival.

Extra-anatomical hepatic artery reconstruction following post-embolization iatrogenic dissection and arterial anastomotic rupture in two liver transplant recipients

When hepatic artery reconstruction is required during hepatic transplantation, this is generally performed with donor vessels. We describe two cases requiring a prosthesis. The first case was a 58-year-old man transplanted for cirrhosis complicated by hepatocellular carcinoma. During transplantation, dissection of the celiac trunk occurred due to arterial embolization and the use of the patient's vessels was impossible. An extra-anatomical bypass between the infra-renal aorta and the donor hepatic artery was performed via the interposition of a graft tube. The second case was a 52-year-old man transplanted for cirrhosis complicated by hepatocellular carcinoma. On day 16, a ruptured anastomosis was suspected and the patient underwent emergency revision laparotomy. Arterial revascularisation was performed with an aortohepatic bypass using a synthetic GoreTex((R)) graft. Patient follow-up was uneventful.

ARTERIAL VASCULAR CONDUITS IN ADULT ORTHOTOPIC LIVER TRANSPLANT RECIPIENTS

BACKGROUND

Vascular conduits may be required to gain arterial inflow to the donor hepatic artery in orthotopic liver transplantation.

METHODS

From January 1986 to December 2003, arterial conduits were required in 31/582 (5.3%) adult liver transplant procedures.

RESULTS

Indications for the conduit included recipient hepatic artery problems (20); hepatic artery thrombosis previous allograft (7) and other (4). The conduits used in 28/31 cases (90%) were deceased donor iliac arteries and the remainder prosthetic grafts. Patients requiring conduits were more likely to be already hospitalized (P = 0.038) or undergoing a retransplant procedure (P = 0.001) than patients not requiring conduits. Both sepsis and haemorrhage caused death in 8/31 (26%) patients requiring conduits versus 42/551 (7.6%) patients not requiring conduits. Death from thrombosis of the iliac artery conduit occurred in two cases and from bacterial infection of a prosthetic conduit in one case. For retransplant procedures, allograft loss was seen in 11/13 (84%) conduit cases versus 11/28 (39%) non-conduit cases (P = 0.016). Overall allograft survival was significantly lower in the conduit cases than in the non-conduit cases (P = 0.0001), with 12/31 (39%) allografts being lost within the first 3 months post-transplantation for the conduit cases.

CONCLUSION

Arterial vascular conduits are more commonly required in adult liver transplant recipients who are hospitalized or undergoing retransplant procedures. Allograft survival is poorer in the conduit cases and is associated with complications, particularly sepsis and haemorrhage, following retransplantation procedures.

Umbilical portion of recipient's left portal vein: a useful vascular conduit in dual living donor liver transplantation for the thrombosed portal vein

We considered performing living donor liver transplantation (LDLT) in a larger-size recipient. When the recipient was large-sized, or when the donor liver was severely steatotic or had a right-to-left volume discrepancy. We devised dual living donor liver transplantation (DLDLT) to make up for graft size insufficiency and to secure the donor's safety. However, portal vein thrombosis (PVT) presented a challenge for DLDLT because of the need for intact right and left portal veins for the implantation of both liver grafts. Our 52-year-old male patient with hepatitis B cirrhosis had suffered from repeated esophageal and gastric variceal bleeding and underwent 2 trials of a transjugular intrahepatic portosystemic shunt (TIPS). He developed TIPS occlusion and PVT involving the area just above the spleno-mesenteric confluence to the right and left PV. Also, the right PV orifice was destructed and difficult to isolate because of severe periportal inflammation and neointima growth in the TIPS mesh. The patient's two sons were inadequate for donation because of right-to-left volume discrepancy. Therefore, DLDLT using 2 left lobes was necessary to compensate for graft-size insufficiency and to secure donor safety, and we substituted an intact umbilical portion of recipient's left PV for the destroyed right PV. The patient recovered well, and liver function has been normal for more than a year. In conclusion, the umbilical portion of recipient's left PV can be a useful vascular substitute for the reconstruction of a thrombosed main portal branch in DLDLT.

Could the use of interposition grafts for arterial reconstruction be avoided by more caudate graft placement in living donor liver transplantation?

One of the major challenges in living donor liver transplantation (LDLT) is short and small vessels (particularly the hepatic artery), particularly in segmental liver grafts from living donors. In the present study we report an alternative surgical technique that avoids interpositional vessel grafts or tension on the connection by anastomizing the allograft hepatic vein to the recipient inferior vena cava in a more caudate location. From March 2000 to January 2003, 28 patients (11 women/17 men) underwent 28 LDLT. Until June 2001, the preferred technique for hepatic vein anastomosis was end-to-end anastomosis between the allograft hepatic vein and the recipient hepatic vein (HV-HV) (n = 10). Thereafter an end-to-side anastomosis was performed between allograft hepatic vein and recipient inferior vena cava (HV-IVC) (n = 18). The level of venotomy on the recipient vena cava was decided according to the pre-anastomotic placement of the allograft in the recipient hepatectomy site with sufficient width to have an hepatic artery anastomosis without tension or need for an interposition graft during hepatic artery and portal vein anastomoses. Except the right lobe allograft with anterior and posterior portal branches, all portal and hepatic artery anastomoses were constructed without an interposition graft or tension in the HV-IVC group. Only one hepatic artery thrombosis developed in the HV-IVC group. As a result, this technique may avoid both hepatic artery thrombosis and the use of interposition grafts in living donor liver transplantation.