Long-term deleterious effects of aortohepatic conduits in primary liver transplantation: proceed with caution

What is the optimal management of thromboprophylaxis after liver transplantation regarding prevention of bleeding, hepatic artery, or portal vein thrombosis? A systematic review of the literature and expert panel recommendations

BACKGROUND

A key tenet of clinical management of patients post liver transplantation (LT) is the prevention of thrombotic and bleeding complications. This systematic review investigated the optimal management of thromboprophylaxis after LT regarding portal vein thrombosis (PVT) or hepatic artery thrombosis (HAT) and prevention of bleeding.

METHODS

Systematic review following PRISMA guidelines and recommendations using the GRADE approach derived from an international expert panel. Seven databases were used to conduct extensive literature searches focusing on the use of anticoagulation in LT and its impact on the following outcomes: PVT, HAT, and bleeding (CRD42021244288).

RESULTS

Of the 2478 articles/abstracts screened, 16 studies were included in the final review. All articles were critically appraised by a panel of independent reviewers. There was wide variation regarding the anticoagulation protocols used. Thromboprophylaxis with therapeutic doses of heparin/Vitamin K antagonist combination did not decrease the risk of de novo or the recurrence of PVT but was associated with an increased risk of bleeding in some studies. Only the use of aspirin resulted in a small but significant decrease in the incidence of HAT post-LT, yet it did not increase the risk of bleeding.

CONCLUSIONS

Based on existing data and expert opinion, thromboprophylaxis at therapeutic or prophylactic dose is not recommended for prevention of de novo PVT following LT in patients not at high risk. Aspirin should be considered as the standard of care following LT to prevent HAT. Thromboprophylaxis should be strongly considered in recipients at risk of HAT and PVT following LT.

Comparison of alternative arterial anastomosis site during liver transplantation when the recipient's hepatic artery is unusable

BACKGROUND

Few studies have analyzed outcomes of liver transplantation (LT) when the recipient hepatic artery (HA) was not usable.

METHODS

We retrospectively evaluated the outcomes of LT performed using the different alternative sites to HA.

RESULTS

Between 2002 and 2017, 1,677 LT were performed in our institution among which 141 (8.4%) with unusable recipient HA were analyzed. Four groups were defined according to the site of anastomosis: the splenic artery (SA group, n=26), coeliac trunk (CT group, n=12), aorta using or not the donor's vessel (Ao group, n=91) and aorta using a vascular prosthesis (Ao-P group, n=12) as conduit. The median number of intraoperative red blood cell transfusions was significantly increased in the Ao and Ao-P groups (5, 5, 8.5 and 16 for SA, CT, Ao and Ao-P group respectively, P=0.002), as well as fresh frozen plasma (4.5, 2.5, 10, 17 for the SA, CT, Ao and Ao-P groups respectively, P=0.001). Hospitalization duration was also significantly increased in the Ao and Ao-P groups (15, 16, 24, 26.5 days for the SA, CT, Ao and Ao-P groups respectively, P<0.001). The occurrence of early allograft dysfunction (EAD) (P=0.07) or arterial complications (P=0.26) was not statistically different. Level of factor V, INR, bilirubin and creatinine during the 7th postoperative days (POD) was significantly improved in the SA group. No difference was observed regarding graft (P=0.18) and patient (P=0.16) survival.

CONCLUSIONS

In case of unusable HA, intraoperative and postoperative outcomes are improved when using the SA or CT compared to aorta.

Microsurgical Hepatic Artery Reconstruction in Deceased Donor Liver Transplantation for Reduced Arterial Complications

Aberrant donor hepatic artery anatomy or hepatic artery injury during organ procurement or recipient preparation poses a surgical challenge during deceased donor liver transplantation. In this study, we aimed to investigate arterial reconstruction using microvascular techniques during deceased donor liver transplantation and suggest reasonable indications for the microsurgical approach in this setting. We retrospectively reviewed the outcomes of 470 deceased donor liver transplantations performed at our institution between July 2011 and December 2015. Of these, 128 recipients underwent microsurgical hepatic artery reconstruction and 342 underwent reconstruction with surgical loupes. Thirty-two patients (6.8%) experienced hepatic artery-related complications, including hepatic artery thrombosis (n = 8, 1.7%). In the propensity score-matched cohort, the surgical loupe group showed a higher complication rate (P = .782). On multivariate analysis, cold ischemia time (odds ratio, 0.995; 95% confidence interval, 0.9920-0.999; P = .009) and use of aortohepatic conduits (odds ratio, 5.254; 95% confidence interval, 1.878-14.699; P = .002) were independent predictors of arterial complications. The low incidence of hepatic artery complications in this study is likely attributable to the active application of microsurgical techniques. Active application of back-table microsurgical plasty and selective application of microsurgical techniques for main arterial reconstruction may help minimize operative difficulties and arterial complications.

Multivisceral Transplantation for Diffuse Portomesenteric Thrombosis: Lessons Learned for Surgical Optimization

Background: Multivisceral transplantation entails the en-bloc transplantation of stomach, duodenum, pancreas, liver and bowel following resection of the native organs. Diffuse portomesenteric thrombosis, defined as the complete occlusion of the portal system, can lead to life-threatening gastrointestinal bleeding, malnutrition and can be associated with liver and intestinal failure. Multivisceral transplantation is the only procedure that offers a definitive solution by completely replacing the portal system. However, this procedure is technically challenging in this setting. The aim of this study is to describe our experience, highlight the challenges and propose technical solutions.

Materials and Methods: We performed a retrospective analysis of our cohort undergoing multivisceral transplantation for diffuse portomesenteric thrombosis at our institution from 2000 to 2020. Donor and recipient demographics and surgical strategies were reviewed in detail and posttransplant complications and survival were analyzed.

Results: Five patients underwent MVTx. Median age was 47 years (23–62). All had diffuse portomesenteric thrombosis with life-threatening variceal bleeding. Major blood loss during exenteration was avoided by combining two techniques: embolization of the native organs followed by a novel, staged extraction. This prevented major perioperative blood loss [median intra-operative transfusion of 3 packed red blood cell units (0–5)]. Median CIT was 330 min (316–416). There was no perioperative death. One patient died due to invasive aspergillosis. Four others are alive and well with a median follow-up of 4.1 years (0.3–5.9).

Conclusions: Multivisceral transplantation should be considered in patients with diffuse portomesenteric thrombosis that cannot be treated by any other means. We propose a standardized surgical approach to limit the operative risk and improve the outcome.

Comparison of Supraceliac and Infrarenal Aortic Conduits in Liver Transplantation: Is There a Difference in Patency and Postoperative Renal Dysfunction?

Aorto-hepatic conduits can provide arterial inflow for liver transplants in cases where the native hepatic artery is unsuitable for use.

Saphenous vein conduits for hepatic arterial reconstruction in living donor liver transplantation

PURPOSE

Occasionally, a recipient's native hepatic arteries are not suitable for reconstruction in living donor liver transplantation (LDLT). The use of the great saphenous vein (GSV) conduits in such patients is seldom practiced since arterial conduits from deceased donors are available. Here, we share our experience with a significantly large group of LDLT recipients who underwent arterial reconstruction with GSV conduits.

METHODS

We reviewed patients who underwent LDLT between 2012 and 2017. Patients who had arterial reconstruction using native hepatic arteries (group 1)(n = 452) were compared with those who had GSV interposition conduits for reconstruction (group 2)(n = 21). We compared hepatic artery thrombosis (HAT) rate, allograft dysfunction, morbidity, mortality, and actuarial 5-year survival in the two groups.

RESULTS

HAT was seen in 0/452 (0%) versus 1/21(4.7%) patients (P = 0.04). Allograft dysfunction was seen in 89/423 (21%) versus 6/19(31.5%) (P = 0.2) patients. Overall mortality was 81/452 (17.9%) versus 8/21(38%) (P = 0.02). Death after a biliary complication was seen in 24/452 (5.3%) versus 4/21 (19%) patients (P = 0.02). Actuarial 1- and 5-year overall survival was 85% versus 67% and 79% versus 58% (P = 0.008).

CONCLUSION

GSV conduits are a suboptimal alternative for establishing hepatic arterial inflow in LDLT, but remain valuable in ominous situations.

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.

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.

Pediatric Liver Transplant: Techniques and Complications

Liver transplant is considered to be the last-resort treatment approach for pediatric patients with end-stage liver disease. Despite the remarkable advance in survival rates, liver transplant remains an intricate surgery with significant morbidity and mortality. Early diagnosis of complications is crucial for patient survival but is challenging given the lack of specificity in clinical presentation. Knowledge of the liver and vascular anatomy of the donor and the recipient or recipients before surgery is also important to avoid complications. In this framework, radiologists play a pivotal role on the multidisciplinary team in both pre- and postoperative scenarios by providing a road map to guide the surgery and by assisting in diagnosis of complications. The most common complications after liver transplant are (a) vascular, including the hepatic artery, portal vein, hepatic veins, and inferior vena cava; (b) biliary; (c) parenchymal; (d) perihepatic; and (e) neoplastic. The authors review surgical techniques, the role of each imaging modality, normal posttransplant imaging features, types of complications after liver transplant, and information required in the radiology report that is critical to patient care. They present an algorithm for an imaging approach for pediatric patients after liver transplant and describe key points that should be included in radiologic reports in the pre- and postoperative settings. Online supplemental material is available for this article. ^©RSNA, 2017.

Placement of an Aortohepatic Conduit as an Alternative to Standard Arterial Anastomosis in Liver Transplantation

Background

The aim of this study was to assess the impact of placement of an aortohepatic conduit on graft and patient survival after liver transplantation (LT) in selected patients with an inadequate recipient hepatic artery (HA) for a standard arterial anastomosis.

Material/Methods

Of 331 patients who underwent deceased donor LT, 25 (7.6%) who received placement of an aortohepatic conduit at the time of transplantation were included. Clinical characteristics and outcomes, including postoperative complications, conduit patency, and graft and patient survival rates, were analyzed.

Results

All 25 patients included in this study presented a high preoperative Model for End-stage Liver Disease score (25.4±8.6; range, 6–42) and high rates of retransplantation (n=11, 44%) or previous abdominal – pelvic surgery (n=5, 20%). The observed postoperative vascular complications were portal vein thrombosis in 3 cases (12%) and anastomosis-site bleeding of the aortohepatic conduit in 1 case (4%); there was no HA thrombosis or stenosis in our analysis. With a median follow-up of 37 months (range, 0–69 months), all aortohepatic conduits were patent, and the graft and patient survival rates were 84% and 68%, respectively. The causes of death were graft failure (n=4), pneumonia (n=3), and cerebrovascular accidents (n=1).

Conclusions

Our results indicate that placement of an aortohepatic conduit is a feasible alternative to a standard arterial anastomosis in selected patients whose HA and surrounding potential inflow arteries are not suitable for standard arterial anastomosis.

Liver transplantation in the treatment of severe iatrogenic liver injuries

The place of liver transplantation in the treatment of severe iatrogenic liver injuries has not yet been widely discussed in the literature. Bile duct injuries during cholecystectomy represent the leading cause of liver transplantation in this setting, while other indications after abdominal surgery are less common. Urgent liver transplantation for the treatment of severe iatrogenic liver injury may-represent a surgical challenge requiring technically difficult and time consuming procedures. A debate is ongoing on the need for centralization of complex surgery in tertiary referral centers. The early referral of patients with severe iatrogenic liver injuries to a tertiary center with experienced hepato-pancreato-biliary and transplant surgery has emerged as the best treatment of care. Despite widespread interest in the use of liver transplantation as a treatment option for severe iatrogenic injuries, reported experiences indicate few liver transplants are performed. This review analyzes the literature on liver transplantation after hepatic injury and discusses our own experience along with surgical advances and future prospects in this uncommon transplant setting.

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 Transplantation Utilizing Mixed Biologic and Synthetic Arterial Conduits

Arterial conduits are necessary in nearly 5% of all liver transplants and are usually constructed utilizing segments of donor iliac artery. However, available segments of donor iliac artery may not be lengthy enough or may not possess enough quality to enable its inclusion in the conduit. Although there are few reports of arterial conduits constructed solely utilizing prosthetic material, no previous reports of conduits composed of a segment of donor iliac artery and prosthetic material (mixed biologic and synthetic arterial conduits) were found in the medial literature to date. Two cases reporting successful outcomes after creation of mixed biologic and prosthetic arterial conduits are outlined in this report. Reason for creation of conduits was complete intimal dissection of the recipient's hepatic artery in both cases. In both cases, available segments of donor iliac artery were not lengthy enough to bridge infrarenal aorta to porta hepatis. Both patients have patent conduits and normally functioning liver allografts, respectively, at 4 and 31 months after transplant. Mixed biologic and synthetic arterial conduits constitute a viable technical option and may offer potential advantages over fully prosthetic arterial conduits.

Liver transplantation for hepatobiliary malignancies: a new era of "Transplant Oncology" has begun

The indications of liver transplantation for hepatobiliary malignancies have been carefully expanded in a stepwise fashion, despite the fundamental limitations in oncological, immunological, and technical aspects. A new era of "Transplant Oncology," the fusion of transplant surgery and surgical oncology, has begun, and we stand at the dawn of a paradigm shift in multidisciplinary cancer treatment. For hepatocellular carcinoma, new strategies have been undertaken to select recipients based on biological and dynamic markers instead of conventional morphological and static parameters, opening the doors for a more deliberate expansion of the Milan criteria and locoregional therapies before liver transplantation. Neoadjuvant chemoradiation therapy followed by liver transplantation for unresectable perihilar cholangiocarcinoma developed by the Mayo Clinic provided excellent outcomes in a US multicenter study; however, the surgical indications are not necessarily universal and await international validation. Similarly, an aggressive multidisciplinary approach has been applied for other tumors, including intrahepatic cholangiocarcinoma, hepatoblastoma, liver metastases from colorectal and neuroendocrine primary and gastrointestinal stromal tumors as well as rare tumors, such as hepatic undifferentiated embryonal sarcoma and infantile choriocarcinoma. In conclusion, liver transplantation is an important option for hepatobiliary malignancies; however, prospective studies are urgently needed to ensure the appropriate patient selection, organ allocation and living donation policies, and administration of antineoplastic immunosuppression.

The recipient celiac trunk as an alternative to the native hepatic artery for arterial reconstruction in adult liver transplantation

During liver transplantation (LT), the recipient hepatic artery (RHA) cannot always be used, and alternatives include aortohepatic conduits and the splenic artery (SA). We report our experience with arterial reconstruction on the recipient celiac trunk (RCT), which has rarely been described. Since January 2013, we have been using the RCT when the RHA could not be used. All cases were discussed in a multidisciplinary LT meeting, and arterial patency or anomalies were systemically viewed with computed tomography (CT) scan. The RCT was used after section-ligation of all celiac trunk collaterals. Until May 2014, the RHA could not be used in 11/139 (8%) patients who underwent LT. Postoperative arterial patency was assessed by serial Doppler ultrasound and CT scan. The advantages and disadvantages of the different arterial conduits were evaluated. The RCT was used in 7/11 (64%) patients. Mean follow-up was 10 (6-15) months. The patency rate was 100%, and 1 patient with associated portal shunting died at day 20 from septic complications. No related gastric or splenic complications were encountered. The RCT could not be used in 4 patients with reconstruction on the SA (n = 2), infrarenal (n = 1), and supraceliac aorta (n = 1). The patency rate was 75%. One patient with SA conduit and portal shunting developed pancreatitis/anastomotic pseudoaneurysm with secondary rupture. An emergency infrarenal conduit was created, which was later embolized because of infected pseudoaneurysms. Although the literature reports a higher risk of thrombosis with aortohepatic conduits, no long-term results are available for the SA conduits, and only 1 report is available for the RCT. In conclusion, this study shows that the RCT is a good alternative to the RHA and can be used in two-thirds of patients with inadequate RHA flow.

Do postliver transplant patients need thromboprophylactic anticoagulation?

Postoperative thromboprophylactic anticoagulation against Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE) is standard of care with current evidence-based guidelines. However, majority of liver transplant (LT) patients have thrombocytopenia and/or prolonged INR before surgery. Studies or guidelines regarding role of prophylactic anticoagulation after LT are lacking. There is a need to balance the risk of thrombosis with significant hemorrhage, implying those needing transfusion or return to OR due to bleeding. We conclude that after LT, anticoagulation is not required routinely for DVT/PE prophylaxis. Rather, it is indicated in specific circumstances, chiefly for prophylaxis of hepatic artery thrombosis or portal vein thrombosis in cases with use of grafts, pediatric cases, small size vessels, Budd Chiari syndrome, amongst others.

Current status of the organ replacement approach for malignancies and an overture for organ bioengineering and regenerative medicine

Significant achievements in the organ replacement approach for malignancies over the last 2 decades opened new horizons, and the age of "Transplant Oncology" has dawned. The indications of liver transplantation for malignancies have been carefully expanded by a strict patient selection to assure comparable outcomes with non-malignant diseases. Currently, the Milan criteria, gold standard for hepatocellular carcinoma, are being challenged by high-volume centers worldwide. Neoadjuvant chemoradiation therapy and liver transplantation for unresectable hilar cholangiocarcinoma has been successful in specialized institutions. For other primary and metastatic liver tumors, clinical evidence to establish standardized criteria is lacking. Intestinal and multivisceral transplantation is an option for low-grade neoplasms deemed unresectable by conventional surgery. However, the procedure itself is in the adolescent stage. Solid organ transplantation for malignancies inevitably suffers from "triple distress," i.e., oncological, immunological, and technical. Organ bioengineering and regenerative medicine should serve as the "triple threat" therapy and revolutionize "Transplant Oncology."