Back-Table Arterial Reconstructions in Liver Transplantation: Single-Center Experience

Microsurgical replacement of the right hepatic artery with the donor superior mesenteric artery in cadaveric donor pediatric liver transplantation

PURPOSE

To present our experience of using the pediatric donor superior mesenteric artery (SMA) as the interpositioning vessel to reconstruct the hepatic artery in pediatric deceased donor liver transplantation.

METHODS

Pediatric patients who received pediatric deceased donor livers from December 2019 to June 2021 were enrolled.

RESULTS

A total of 43 pediatric recipients received pediatric deceased donor livers during the study period. Thirty-four (79.1%) pediatric donors had normal hepatic artery anatomy, while nine (20.9%) showed variant anatomies. The SMAs of the pediatric donors were interposed in the latter eight cases. The anastomosis between the donor distal SMA and the donor celiac trunk artery (CTA) was initially performed in the back-table period, after which the other anastomosis between the donor proximal SMA and recipient CHA was performed. Only one case showed HAT occurrence (incidence rate, 2.3%). However, no arterial complications occurred in pediatric recipients with donor grafts that showed the variation of RHA replacement from the SMA and had undergone usage of the donor's SMA as an interpositioning vessel.

CONCLUSIONS

In pediatric deceased donor liver transplantation, the use of SMA as an interpositioning medium can solve the problems related to a tiny caliber and anatomical variations of the donor hepatic artery.

Impact of Hepatic Artery Variations and Reconstructions on the Outcome of Orthotopic Liver Transplantation

BACKGROUND

Donor variational arteries often require complex reconstruction.

METHODS

We analysed the incidence of different variations, types of arterial reconstructions and their impact on post-operative results from 409 patients undergoing liver transplantation at Karolinska Institute between 2007 and 2015.

RESULTS

A total of 292 (71.4%) liver grafts had a standard hepatic artery (SHA), and 117 (28.6%) showed hepatic artery variants (HAV). 58% of HAV needed reconstruction. The main variations were variant left hepatic artery (45.3%) from the gastric artery; variant right hepatic artery (38.5%); and a triple combination of variant right and left hepatic artery and the proper hepatic artery from the common hepatic artery (12.8%); other 3.4%. Patients/graft survival and arterial complications were not different between SHA and HAV. Incidence of biliary stricture was numerically higher in left hepatic artery variants (p = 0.058) and in variants where no arterial reconstruction was performed (p = 0.001). Operation and arterial warm ischaemia time were longer in the HAV group. The need for intraoperative re-reconstruction was higher in the HAV group (p = 0.04). Intraoperative bleeding was larger after back-table reconstruction than with intraoperative reconstruction (p = 0.04).

CONCLUSION

No overall differences were found between the HAV and the SHA groups. Occurrence of a variant left hepatic artery and HAV with no reconstruction seems to increase the risk of biliary strictures.

Hepatic artery occlusion in liver transplantation: What counts more, the type of reconstruction or the severity of the recipient's disease?

Although the type of hepatic artery revascularization technique is known to have an impact on patency rates, independent perioperative risk factors on patient outcomes are poorly defined. All consecutive adult patients undergoing cadaveric liver transplantation (n = 361) from July 2007 to June 2016 in a single institution were analyzed. Primary outcomes were early (<30 days) hepatic artery occlusion and primary hepatic artery patency rate. A multivariate model was used to identify independent risk factors for occlusion and the need of arterial conduit, as well as their impact on graft and patient survival. Arterial revascularization without additional reconstruction (end-to-end arterial anastomosis [AA]) was performed in 77% (n = 279), arterial reconstruction (AR) in 15% (n = 53), and aortohepatic conduit (AHC) in 8% (n = 29) of patients. AHC had the highest mean intraoperative flow (275 mL/minute; P = 0.02) compared with AA (250 mL/minute) and AR (200 mL/minute; P = 0.02). There were 43 recipients (12%) who had an occlusive event with successful revascularization in 20 (47%) recipients. One-year primary patency rates of AA, AR, and AHC were 97%, 88%, and 74%, respectively. Aortic calcification had an impact on early occlusion. AR (odds ratio [OR], 3.68; 95% confidence interval [CI], 1.26-10.75; P = 0.02) and AHC (OR, 6.21; 95% CI, 2.02-18.87; P = 0.001) were independent risk factors for early occlusion. Dyslipidemia additionally independently contributed to early occlusion (OR, 2.74; 95% CI, 0.96-7.87; P = 0.06). The 1- and 5-year graft survival rates were 83% and 70% for AA, 75% and 69% for AR, and 59% and 50% for AHC (P = 0.004), respectively. In conclusion, arterial patency is primarily determined by the type of vascular reconstruction rather than patient or disease characteristics. The preoperative lipid status is an independent risk factor for early occlusion, whereas overall occlusion is only based on the performed vascular reconstruction, which is also associated with reduced graft and patient survival. Liver Transplantation 24 790-802 2018 AASLD.

Liver transplant recipients with portal vein thrombosis receiving an organ from a high-risk donor are at an increased risk for graft loss due to hepatic artery thrombosis

We hypothesize that recipients with pretransplant portal vein thrombosis (PVT) receiving organs from high-risk donors (HRD) are at an increased risk of HAT. Data on all liver transplants in the United States from February 2002 to March 2015 were analyzed. Recipients were sorted into two groups: those with PVT and those without. HRDs were defined by donor risk index (DRI) >1.7. Multivariable logistic regression models were constructed to assess the independent risk factors for HAT with the resultant graft loss ≤90 days from transplantation. A total of 60 404 candidates underwent liver transplantation; of those recipients, 623 (1.0%) had HAT, of which 66.0% (n = 411) received organs from HRDs compared with 49.3% (n = 29 473) in recipients without HAT (P < 0.001); 2250 (3.7%) recipients had pretransplantation PVT and received organs from HRDs. On adjusted multivariable analysis, PVT with a HRD organ was the most significant independent risk factor (OR 3.56, 95% CI 2.52-5.02, P < 0.001) for the development of HAT. Candidates with pretransplant PVT who receive an organ from a HRD are at the highest risk for postoperative HAT independent of other measurable factors. Recipients with pretransplant PVT would benefit from careful donor selection and possibly anticoagulation perioperatively.

Pre-transplant portal vein thrombosis is an independent risk factor for graft loss due to hepatic artery thrombosis in liver transplant recipients

BACKGROUND

Hepatic artery thrombosis is an uncommon but catastrophic complication following liver transplantation. We hypothesize that recipients with portal vein thrombosis are at increased risk.

METHODS

Data on all liver transplants in the U.S. during the MELD era through September 2014 were obtained from UNOS. Status one, multivisceral, living donor, re-transplants, pediatric recipients and donation after cardiac death were excluded. Logistic regression models were constructed for hepatic artery thrombosis with resultant graft loss within 90 days of transplantation.

RESULTS

63,182 recipients underwent transplantation; 662 (1.1%) recipients had early hepatic artery thrombosis; of those, 91 (13.8%) had pre-transplant portal vein thrombosis, versus 7.5% with portal vein thrombosis but no hepatic artery thrombosis (p < 0.0001). Portal vein thrombosis was associated with an increased independent risk of hepatic artery thrombosis (OR 2.17, 95% CI 1.71-2.76, p < 0.001) as was donor risk index (OR 2.02, 95% CI 1.65-2.48, p < 0.001). Heparin use at cross clamp, INR, and male donors were all significantly associated with lower risk.

DISCUSSION

Pre-transplant portal vein thrombosis is associated with post-transplant hepatic artery thrombosis independent of other factors. Recipients with portal vein thrombosis might benefit from aggressive coagulation management and careful donor selection. More research is needed to determine causal mechanism.

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.

Reconstrução arterial no transplante hepático: a melhor reconstrução para variação da artéria hepática direita

INTRODUÇÃO: Variações na anatomia da artéria hepática são comuns, com incidência de 20-50%. No transplante hepático, reconstruções durante a operção de bandeja são frequentemente necessárias para proporcionar anastomoses arteriais adequadas. O uso de "patch" é frequente, visando reduzir a incidência de complicações. Entretanto, quando está presente a variação da artéria hepática direita, ramo da artéria mesentérica superior, a reconstrução ocasionalmente produz torções e problemas de fluxo. MÉTODOS: Descreve-se uma técnica cirúrgica alternativa para reconstrução da variação da artéria hepática direita usando um "patch de Carrel" da artéria mesentérica superior. O "patch" é anastomosado no coto da artéria esplênica permitindo orientação vertical e bom fluxo sanguíneo. RESULTADOS: Entre 120 transplantes hepáticos, quatro casos consecutivos de variação da artéria hepática direita foram reconstruídas utilizando essa técnica. Todos eles apresentaram patência e bom fluxo no pós-operatório. CONCLUSÃO: A técnica proposta mostra-se interessante método alternativo para reconstrução da variação da artéria hepática direita no transplante hepático.

Progress in surgical techniques in pediatric liver transplantation

Pediatric LT has evolved into an accepted treatment modality for children with end-stage liver disease with excellent long-term graft and patient survival. A number of factors have been critical in the improvement in recipient outcomes including a change in organ donation from donation after cardiac death, to donation after brain death, and more recently live donor LT and a better appreciation of hepatic anatomy allowing for split LT, LDLT, auxiliary partial orthotopic LT, and laparoscopic donor hepatectomy. In this review we summarize the surgical advances that have occurred in pediatric LT that have been important in shaping what is now considered by many to be a routine operation.

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.

Increased risk of graft loss from hepatic artery thrombosis after liver transplantation with older donors

Hepatic artery thrombosis (HAT) is the most common vascular complication after liver transplantation; it has been reported to occur in 2% to 5% of liver transplant recipients. Most reports of HAT in the literature describe single-center series with small numbers of patients and lack the power to definitively identify nontechnical risk factors. We used the United Network for Organ Sharing database of adult deceased donor liver transplants from 1987 to 2006 to identify 1246 patients with graft loss from HAT. Univariate and multivariate regression analyses were performed to identify donor and graft risk factors for HAT-induced graft loss. Although most donor predictors of HAT-induced graft loss were surrogates for vessel size, donor age > 50 years was also a significant predictor of graft loss from HAT (relative risk = 1.45, P < 0.001). Furthermore, the risk of graft loss from HAT increased progressively with each decade of donor age > 50 years, such that a 61% increased risk of HAT-related graft loss (relative risk = 1.61, P < 0.001) was associated with donor age > 70 years. A separate analysis of risk factors for early HAT graft loss (<or=90 days) and late HAT graft loss (> 90 days) found that older donor age was associated with increased late HAT graft loss. These findings are of interest in an era of ongoing organ shortages requiring maximum utilization of potential allografts and increasing allocation of older allografts.

Early hepatic artery thrombosis after liver transplantation: a systematic review of the incidence, outcome and risk factors

To clarify inconsistencies in the literature we performed a systematic review to identify the incidence, risk factors and outcome of early hepatic artery thrombosis (eHAT) after liver transplantation. We searched studies identified from databases (MEDLINE, EMBASE, Science Citation Index) and references of identified studies. Seventy-one studies out of 999 screened abstracts were eligible for this systematic review. The incidence of eHAT was 4.4% (843/21, 822); in children 8.3% and 2.9% in adults (p < 0.001). Doppler ultrasound screening (DUS) protocols varied from 'no routine' to 'three times a day.' The median time to detection was at day seven. The overall retransplantation rate was 53.1% and was higher in children (61.9%) than in adults (50%, p < 0.03). The overall mortality rate of patients with eHAT was 33.3% (range: 0-80%). Mortality in adults (34.3%) was higher than in children (25%, p < 0.03). The reported risk factors for eHAT were, cytomegalovirus mismatch (seropositive donor liver in seronegative recipient), retransplantation, arterial conduits, prolonged operation time, low recipient weight, variant arterial anatomy, and low volume transplantation centers. eHAT is associated with significant graft loss and mortality. Uniform definitions of eHAT and uniform treatment modalities are obligatory to confirm these results and to obtain a better understanding of this disastrous complication.

Liver transplantation: vascular complications

Transplantation has become the method of choice for treatment of patients with irreversible severe liver dysfunction. Vascular thrombosis or stenosis, biliary obstruction, hemorrhage, posttransplantation neoplasm, and rejection are some of the most common potential complications. Most complications cause significant morbidity and mortality after liver transplantation. The appearance of vascular complications in posttransplantation patients is illustrated in this article.