Recipient outcomes after ABO-incompatible liver transplantation: a systematic review and meta-analysis

Global research hotspots and trends of acute rejection after liver transplantation from 1988 to 2022: a bibliometric analysis

Background: Acute rejection (AR) is the predominant form of rejection observed in liver transplantation and plays a crucial role in transplant immunology. This study aims to utilize bibliometric analysis to understand the status quo, hotspots, and future trends of research on AR after liver transplantation. Methods: We searched the Web of Science Core Collection (WoSCC) for studies on AR after liver transplantation published from 1988 to 2022. The Bibliometric Online Analysis Platform, VOSviewer, and CiteSpace were used for analysis of all extracted publications. Results: This study included 2,398 articles published in 456 journals by 12,568 authors from 1,965 institutions in 55 countries/regions. The United States and its affiliated institution, the University of Pittsburgh, were the most productive contributors. Transplantation (n = 12,435) was the most frequently cited journal. Neuhaus P (n = 38) was the highest output author, and Demetris AJ (n = 670) was the most co-cited author. The research hotspots of AR after liver transplantation include pathogenesis, immunosuppressive therapy, and prognosis. Emerging research directions include regulatory T cells, immunosuppression minimization, intra-patient variability (IPV) of tacrolimus, and novel non-invasive diagnostic markers. Conclusion: Our study utilized bibliometric methods to analyze the study of AR after liver transplantation over the past 35 years. With the prolonged survival of liver transplant recipients, the most active areas currently focus on individualized treatment and improving patient prognosis. Minimizing adverse reactions to immunosuppressive therapy while simultaneously avoiding an increase in the risk of AR remains a future research focus.

A Retrospective Study of Long-Term Outcomes in 16 ABO-Incompatible Deceased Donor Pediatric Liver Transplants from a National Transplant Center at Helsinki University Hospital, Finland, 1987-2022

BACKGROUND The use of ABO-incompatible liver transplants (ABO-ILTs) from deceased donors has become more common due to the shortage of available donor livers and increased transplant waiting times. This retrospective study from a national transplant center at Helsinki University Hospital, Finland, aimed to assess the long-term outcomes of ABO-incompatible deceased donor pediatric liver transplants between 1987 and 2022. MATERIAL AND METHODS Sixteen (9.5%) of the 169 pediatric liver transplantations were ABO-ILTs. The median age at transplantation was 5.0 (0.5-15.4) years. Reasons for ABO-ILTs were acute liver failure (18.75%), malignancy (12.5%), small body size and long waiting time (25%), and other reasons (43.75%). The median post-transplant follow-up time was 147 (0.72-353) months. Patient and graft survival and occurrence of surgical complications were compared to ABO-identical transplants, and anti-ABO antibody titers were analyzed. RESULTS The 1-, 3-, and 5-year patient survivals were comparable between the ABO-I and ABO-compatible groups, being 81.3%, 73.9%, and 73.9% (ABO-I) and 87.5%, 82.5%, 77.9% (ABO-compatible), respectively. Three patients with ABO-ILTs died of sepsis and multiorgan failure during the first 3 months after transplantation. The occurrence of biliary complications and early vascular thrombosis (<30 days after transplantation) did not differ significantly between recipients with an ABO-ILT vs ABO-compatible liver graft. CONCLUSIONS The findings from this study support findings from previous studies that outcomes after ABO-incompatible liver transplants in children were comparable to outcomes from ABO-identical liver transplants.

Implementing living-donor pediatric liver transplantation in Southern Vietnam: 15-year results and perspectives

BACKGROUND

ND2 in Ho Chi Minh City is currently the only public center that performs PLT in Southern Vietnam. In 2005, the first PLT was successfully performed, with support from Belgian experts. This study reviews the implementation of PLT at our center and evaluates the results and challenges.

METHODS

Implementation of PLT at ND2 required medico-surgical team building and extensive improvement of hospital facilities. Records of 13 transplant recipients from 2005 to 2020 were studied retrospectively. Short- and long-term complications, as well as the survival rates, were reported.

RESULTS

The mean follow-up time was 8.3 ± 5.7 years. Surgical complications included one case of hepatic artery thrombosis that was successfully repaired, one case of colon perforation resulting in death from sepsis, and two cases of bile leak that were drained surgically. PTLD was observed in five patients, of whom three died. There were no cases of retransplantation. The 1-year, 5-year, and 10-year patient survival rates were 84.6%, 69.2%, and 69.2%, respectively. There were no cases of complication or death among the donors.

CONCLUSION

Living-donor PLT was developed at ND2 for providing a life-saving treatment to children with end-stage liver disease. Early surgical complication rate was low, and the patient survival rate was satisfactory at 1 year. Long-term survival decreased considerably due to PTLD. Future challenges include surgical autonomy and improvement of long-term medical follow-up with a particular emphasis on prevention and management of Epstein-Barr virus-related disease.

Paired Exchange Living Donor Liver Transplantation: A Nine-year Experience From North India

BACKGROUND

Paired exchange liver transplantation is an evolving strategy to overcome ABO blood group incompatibility and other barriers such as inadequate graft-to-recipient weight ratio and low remnant liver volume in donors. However, for the transplant team to carry 4 major operations simultaneously is a Herculean effort. We analyzed our experience with liver paired exchange (LPE) program over the past 9 y.

METHODS

This prospective study included 34 of 2340 (1.45%) living donor liver transplantations performed between May 2012 and April 2021. The reason for LPE was ABO incompatibility in all (n = 34) patients included in the study. After donor reassignment through 2-by-2 paired exchange with directed donors, the ABO matching status changed from A to A (n = 17) and B to B (n = 17), which made all matches ABO-identical. Recipients (R) and donors (D) of each swap pair were prospectively divided into R1/D1 and R2/D2 groups for comparative and survival analyses.

RESULTS

The recipients (n = 34) had a median age of 45.5 y (11-59 y), and 31 were men. LPEs were performed in 4 operating rooms running simultaneously by 2 independent surgical teams. Donor survival was 100%. Baseline clinical and perioperative parameters, postoperative complications, median intensive care unit/hospital stay, and early deaths were comparable (P > 0.1) between the R1 and R2 groups. The median follow-up period was 27 mo (1-108 mo). The 30-d and 1-y survivals were 88.2% (n = 30) and 85.3% (n = 29), respectively.

CONCLUSIONS

Our experience suggests that with careful attention to ethical and logistical issues, the LPE program can expand the living donor liver pool and facilitate a greater number of living donor liver transplantations.

Fatal intracardiac and pulmonary arterial thromboembolic damage following ABO-incompatible living donor liver transplantation for autoimmune hepatitis: A case report

RATIONALE

We present the case of a patient with autoimmune hepatitis who suffered fatal intracardiac and pulmonary arterial thromboembolic complications after ABO-incompatible living donor liver transplantation (ABOi LDLT) with splenectomy.

PATIENT CONCERNS

A 46-year-old female (blood type B+) with autoimmune hepatitis and hepatitis B carrier status underwent elective ABOi LDLT. The donor liver was from a 51-year-old male living donor (blood type A+). A splenectomy was performed without bleeding complications. Intraoperatively, the patients hemodynamic condition was acceptable, with no evidence of thromboembolism on transesophageal echocardiography (TEE).

DIAGNOSIS

Postoperatively, her platelet count increased from 15.0 to 263.0 (× 109/L) and thromboelastographic parameters indicated hypercoagulable state. She suffered acute circulatory collapse, respiratory distress and, eventually, a decline in mental status. The attending physicians in the intensive care unit (ICU) immediately performed resuscitation.

INTERVENTIONS

The patient underwent emergency exploratory surgery. Intraoperatively, hypotension, bradycardia and arrhythmia developed, together with high central venous pressure. Assessment of cardiac structure and function using rescue TEE incidentally identified multiple, huge thromboembolic clots in the cardiac chambers; therefore, the patient underwent cardiac thromboembolectomy, including cardiopulmonary bypass with hypothermia therapy.

OUTCOMES

Due to severe cardiac and respiratory distress, the patient required venoarterial extracorporeal membrane oxygenation (VAECMO) in the operating room and ICU. Despite continuous resuscitation in the ICU and maintenance of VAECMO, she suffered severe hypotension and massive bleeding that eventually led to death.

LESSONS

In patients with autoimmune hepatitis, risk factors for thromboembolism should be rigorously controlled during the peak period of reactive thrombocytosis after ABOi LDLT with splenectomy.

ABO-nonidentical liver transplantation from a deceased donor and clinical outcomes following antibody rebound: A case report

BACKGROUND

Although ABO-nonidentical and ABO-incompatible liver transplantation (LT) are other options for end-stage liver disease treatment, the development of antibodies against blood group antigens (anti-A/B antibodies) is still a challenge in managing and follow-up of the recipients.

CASE SUMMARY

A 56-year-old male with end-stage liver disease with rapid deterioration and poor prognosis was considered to receive a deceased ABO-nonidentical liver graft. All required tests were performed according to our pre-LT diagnostic protocol. The orthotopic LT procedure involving O+ donor and A1B+ recipient was performed. Our treatment strategy to overcome the antibody‐mediated rejection included a systemic triple immunosuppressive regimen: methylprednisolone, mycophenolate mofetil, and tacrolimus. The immunological desensitization consisted of the chimeric anti-CD20 monoclonal antibody rituximab and intravenous immunoglobulins. The patient was also on antibiotic treatment with amoxicillin/clavulanate, cefotaxime, and metronidazole. On the 10^th postoperative day, high titers of IgG anti-A and anti-B antibodies were found in the patient’s plasma. We performed a liver biopsy, which revealed histological evidence of antibody-mediated rejection, but the rejection was excluded according to the Banff classification. The therapy was continued until the titer decreased significantly on the 18^th postoperative day. Despite the antibiotic, antifungal, and antiviral treatment, the patient deteriorated and developed septic shock with anuria and pancytopenia. The conservative treatment was unsuccessful, which lead to the patient’s fatal outcome on the 42^nd postoperative day.

CONCLUSION

We present a patient who underwent ABO-nonidentical LT from a deceased donor. Even though we implemented the latest technological advancements and therapeutic approaches in the management of the patient and the initial results were promising, due to severe infectious complications, the outcome was fatal.

Impact of ABO-incompatibility on hepatic artery thrombosis in living donor liver transplantation

Background

The current era of rituximab-based regimens brought improved survival in ABO-incompatible (ABO-I) living donor liver transplantation (LDLT). Nevertheless, the actual risk for hepatic artery thrombosis (HAT) still remains to be investigated. The aim of this study was to evaluate the impact of ABO-incompatibility on HAT in adult LDLT patients.

Methods

Patients who received ABO-I LDLT were compared to those who received ABO-compatible (ABO-C) LDLT with a special focus on HAT.

Results

A total of 378 patients underwent LDLT from January 2012 to February 2018. Of those, ABO-I LDLT was performed in 78 consecutive patients. The other 300 patients with ABO-C LDLT constituted the comparator group. No significant differences were observed between the two groups in baseline and perioperative characteristics. HAT occurred in 11 (2.9%) patients, 2 and 9 patients in ABO-I and ABO-C LDLT groups, respectively, which didn't show any significant difference between the two groups (P=0.84). All were categorized into early HAT. Immediate revascularization by intraarterial thrombolysis was successfully employed in 8 patients. Surgical revision of anastomosis and retransplantation were performed in 1 and 2 patients, respectively. No one-year mortality was related to HAT in the two groups. The overall outcomes including biliary complications made no significant difference between the two groups.

Conclusions

ABO-incompatibility has no adverse impact on the incidence and treatment outcome of HAT in the current rituximab-based desensitization.

ABO-Incompatible Adult Living Donor Liver Transplantation in the Era of Rituximab: A Systematic Review and Meta-Analysis

Aim

The primary aim of this study is to compare the short- and long-term outcomes between ABO-incompatible (ABOi) adult living donor liver transplantation (ALDLT) with rituximab prophylaxis and ABO-compatible (ABOc) ALDLT.

Background

The strategy of ABOi liver transplantation (LT) was originated initially to increase the donor pool and to enable liver transplantation in emergency conditions. However, ABOi ALDLT remains a controversial approach in comparison to ABOc ALDLT.

Methods

PubMed, Embase, and the Cochrane Library study search were accomplished to recognize studies comparing ABOi and ABOc ALDLT. Meta-analyses were conducted based on the evaluation of heterogeneity using a fixed-effect model and a random-effect model to assess the short- and long-term outcomes following ABOi ALDLT with rituximab prophylaxis.

Results

Nine studies comprising a total of 3,922 patients (ABOi = 671 and ABOc = 3,251) were identified. There was no significant difference between ABOi and ABOc groups for 1-year, 3-year, and 5-year OS and graft survival, respectively. Moreover, 1-year and 3-year OS and DFS were similar between both groups for HCC patients. However, ABOi ALDLT had higher incidences of CMV infection, AMR, overall biliary complications, and biliary stricture than ABOc ALDLT and had other comparable postoperative complications.

Conclusion

Our meta-analysis included studies comparing ABOi and ABOc ALDLT after the introduction of rituximab in a desensitization protocol for ABOi ALDLT. The results of ABOi ALDLT were comparable with those of ABOc ALDLT. However, biliary complications, CMV infection, and AMR remain a concern in the era of rituximab.

ABO-incompatible deceased donor pediatric liver transplantation: Novel titer-based management protocol and outcomes

ABO-ILT have re-emerged as an alternate option for select patients awaiting transplant. However, treatment protocols for children undergoing deceased donor ABO-ILT are not standardized. We implemented a novel IS protocol for children undergoing deceased donor ABO-ILT based on pretransplant IH titers. Children with high pretransplant IH titers (≥1:32) underwent an enhanced IS protocol including plasmapheresis, rituximab, IVIG, and mycophenolate, while children with IH titers ≤1:16 received steroids and tacrolimus. We retrospectively assessed our outcomes of ABO-ILT with ABO-compatible recipients of similar age and diagnosis over a 2-year period. Ten children with median age of 8.9 months underwent ABO-ILT, 4 of 10 patients underwent enhanced IS due to high IH titers. Rates of complications (rejection, infections, biliary, and vascular) at both 1 year and up to 3 years post-transplant were comparable between the groups. Patients with ABO-ILT had good graft function with 100% survival at a median follow-up of 3.3 years. In conclusion, IS tailored to pretransplant IH titers in pediatric deceased donor ABO-ILT is feasible and can achieve outcomes similar to ABO-CLT at 1 and 3 years post-transplantation.

Impact of machine perfusion of the liver on post-transplant biliary complications: A systematic review

AIM

To review the clinical impact of machine perfusion (MP) of the liver on biliary complications post-transplantation, particularly ischaemic-type biliary lesions (ITBL).

METHODS

This systematic review was performed in accordance with the Preferred Reporting Systematic Reviews and Meta-Analysis (PRISMA) protocol. The following databases were searched: PubMed, MEDLINE and Scopus. The keyword “liver transplantation” was used in combination with the free term “machine perfusion”. Clinical studies reporting results of transplantation of donor human livers following ex situ or in situ MP were analysed. Details relating to donor characteristics, recipients, technique of MP performed and post-operative biliary complications (ITBL, bile leak and anastomotic strictures) were critically analysed.

RESULTS

Fifteen articles were considered to fit the criteria for this review. Ex situ normothermic MP was used in 6 studies, ex situ hypothermic MP in 5 studies and the other 4 studies investigated in situ normothermic regional perfusion (NRP) and controlled oxygenated rewarming. MP techniques which have per se the potential to alleviate ischaemia-reperfusion injury: Such as hypothermic MP and NRP, have also reported lower rates of ITBL. Other biliary complications, such as biliary leak and anastomotic biliary strictures, are reported with similar incidences with all MP techniques. There is currently less clinical evidence available to support normothermic MP as a mitigator of biliary complications following liver transplantation. On the other hand, restoration of organ to full metabolism during normothermic MP allows assessment of hepatobiliary function before transplantation, although universally accepted criteria have yet to be validated.

CONCLUSION

MP of the liver has the potential to have a positive impact on post-transplant biliary complications, specifically ITBL, and expand extended criteria donor livers utilisation.

Non-anastomotic strictures after transplanting a liver graft with an accidentally ligated and unflushed common bile duct: A case report

Introduction

Non-anastomotic biliary strictures (NAS) represent a major cause of morbidity, graft loss, and mortality after liver transplantation (LTx). NAS can result from an ischemic/immune-mediated injury, or from the cytotoxic effect that bile salts have on the biliary mucosa under hypothermic conditions. For this reason it is crucial to flush the bile duct at the time of procurement.

Presentation of case

We report a case of an imported liver with an accidentally ligated and subsequently completely unflushed common bile duct. The recipient was a 60 year-old man suffering from hepatocellular carcinoma and post-alcoholic cirrhosis. Post-operative course was uneventful and the patient was discharged after 18 days. Within 2 months post-transplantation, a rapidly evolving cholestasis was diagnosed. Endoscopic-retrograde-cholangio-pancreaticography revealed diffuse NAS. Due to the rapid clinical and biochemical deterioration there was no other option than re-transplantation.

Discussion

Suboptimally flushed bile ducts are often encountered and represent a risk factor for NAS after LTx. This unique case represented an extreme form where the biliary tree was not flushed at all. The dilemma of this unforeseen situation raised the question to transplant or discard this liver for transplantation? Given the organ shortage, the pressure to use less-than-ideal organs, the otherwise normal aspect of the liver and our incapacity to predict with certainty the development (or not) of NAS, we accepted this liver for transplantation.

Conclusion

This case illustrates a contrario the importance of flushing the bile duct and risk of extensive dissection of the hepatic hilum at the time of procurement.

Summary of the British Transplantation Society UK Guidelines for Living Donor Liver Transplantation

The British Transplantation Society Guidelines for Living Donor Liver Transplantation was published in July 2015 and is the first national guideline in the field of living donor liver transplantation. The guideline aims to review the evidence relating to the evaluation process of both recipient and donor candidates; address the moral and ethical issues surrounding the procedure; outline the technical aspects of the procedure, including the middle hepatic vein controversy and the "small for size syndrome"; review donor and recipient outcomes and complications including donor mortality; and examine evidence relating to the advantages and disadvantages of living donor liver transplantation. In line with previous guidelines published by the BTS, the guideline has used the Grading of Recommendations Assessment, Development and Evaluation system to rate the strength of evidence and recommendations. This article summarizes the Statements of Recommendation contained in the guideline, which provide a framework for the delivery of living liver donation in the United Kingdom and may be of wide international interest. It is recommended that the full guideline document is consulted for details of the relevant references and evidence base. This may be accessed at http://www.bts.org.uk/BTS/Guidelines_Standards/Current/BTS/Guidelines_Standards/Current_Guidelines.aspx?hkey=e285ca32-5920-4613-ac08-fa9fd90915b5.

ABO-Incompatible Living Donor Liver Transplantation in Focus of Antibody Rebound

BACKGROUND

Living donor liver transplantation (LDLT) is an option to expand the donor organ pool for patients with life-threatening diseases who cannot be supplied with a cadaver organ. Next to the donor risks, complications after ABO-incompatible LDLT (ABOi LDLT) in the recipient are subject to controversial discussion. Improvement in ABOi graft survival rates have been achieved with plasma treatment procedures (PTP) and immunosuppression but antibody-mediated rejection (AMR) and graft loss still occur.

METHODS

Since 2008, we have prepared 10 patients for ABOi LDLT. Seven of the 10 patients for transplantation had hepatocellular carcinoma (HCC).

RESULTS

All patients underwent PTP before and after ABOi LDLT as well as immunosuppression according to the treatment schedule. We did not use anti-CD20 monoclonal antibodies in the transplant setting. We transplanted 6 of 10 preconditioned patients. After 3 years, 5 of the 6 transplanted patients were still alive.

CONCLUSION

Even if B-cell depletion with anti-CD 20 treatment in the setting of ABOi LDLT is commonly accepted, our center successfully administered only quadruple drug immunosuppression combined with PTP. Especially patients with HCC had a high titer increment also pre-transplantation and were at high risk for arterial thrombosis and graft loss.

Current techniques for AB0-incompatible living donor liver transplantation

For a long time, it was considered medical malpractice to neglect the blood group system during transplantation. Because there are far more patients waiting for organs than organs available, a variety of attempts have been made to transplant AB0-incompatible (AB0i) grafts. Improvements in AB0i graft survival rates have been achieved with immunosuppression regimens and plasma treatment procedures. Nevertheless, some grafts are rejected early after AB0i living donor liver transplantation (LDLT) due to antibody mediated rejection or later biliary complications that affect the quality of life. Therefore, the AB0i LDLT is an option only for emergency situations, and it requires careful planning. This review compares the treatment possibilities and their effect on the patients’ graft outcome from 2010 to the present. We compared 11 transplant center regimens and their outcomes. The best improvement, next to plasma treatment procedures, has been reached with the prophylactic use of rituximab more than one week before AB0i LDLT. Unfortunately, no standardized treatment protocols are available. Each center treats its patients with its own scheme. Nevertheless, the transplant results are homogeneous. Due to refined treatment strategies, AB0i LDLT is a feasible option today and almost free of severe complications.

Functional Immune Anatomy of the Liver-As an Allograft

The liver is an immunoregulatory organ in which a tolerogenic microenvironment mitigates the relative "strength" of local immune responses. Paradoxically, necro-inflammatory diseases create the need for most liver transplants. Treatment of hepatitis B virus, hepatitis C virus, and acute T cell-mediated rejection have redirected focus on long-term allograft structural integrity. Understanding of insults should enable decades of morbidity-free survival after liver replacement because of these tolerogenic properties. Studies of long-term survivors show low-grade chronic inflammatory, fibrotic, and microvascular lesions, likely related to some combination of environment insults (i.e. abnormal physiology), donor-specific antibodies, and T cell-mediated immunity. The resultant conundrum is familiar in transplantation: adequate immunosuppression produces chronic toxicities, while lightened immunosuppression leads to sensitization, immunological injury, and structural deterioration. The "balance" is more favorable for liver than other solid organ allografts. This occurs because of unique hepatic immune physiology and provides unintended benefits for allografts by modulating various afferent and efferent limbs of allogenic immune responses. This review is intended to provide a better understanding of liver immune microanatomy and physiology and thereby (a) the potential structural consequences of low-level, including allo-antibody-mediated injury; and (b) how liver allografts modulate immune reactions. Special attention is given to the microvasculature and hepatic mononuclear phagocytic system.

Living Donor Liver Transplantation in Children: Surgical and Immunological Results in 250 Recipients at Université Catholique de Louvain

OBJECTIVES

To evaluate the outcome of pediatric living donor liver transplantation (LDLT) regarding portal vein (PV) reconstruction, ABO compatibility, and impact of maternal donation on graft acceptance.

BACKGROUND

LDLT and ABO-mismatched transplantation constitute feasible options to alleviate organ shortage in children. Vascular complications of portal hypoplasia in biliary atresia (BA) and acute rejection (AR) are still major concerns in this field.

METHODS

Data from 250 pediatric LDLT recipients, performed at Cliniques Universitaires Saint-Luc between July 1993 and June 2012, were collected retrospectively. Results were analyzed according to ABO matching and PV complications. Uni- and multivariate analyses were performed to study the impact of immunosuppression, sex matching, and maternal donation on AR rate.

RESULTS

Overall, the 10-year patient survival rate was 93.2%. Neither patient or graft loss nor vascular rejection, nor hemolysis, was encountered in the ABO nonidentical patients (n = 58), provided pretransplant levels of relevant isoagglutinins were below 1/16. In BA recipients, the rate of PV complications was lower after portoplasty (4.6%) than after truncal PV anastomosis (9.8%) and to jump graft interposition (26.9%; P = 0.027). In parental donation, maternal grafts were associated with higher 1-year AR-free survival (55.2%) than paternal grafts (39.8%; P = 0.041), but only in BA patients.

CONCLUSIONS

LDLT, including ABO-mismatched transplantation, constitutes a safe and efficient therapy for liver failure in children. In BA patients with PV hypoplasia, portoplasty seems to constitute the best technique for PV reconstruction. Maternal donation might be a protective factor for AR.

ABO-Incompatible Adult Living Donor Liver Transplantation Under the Desensitization Protocol With Rituximab

ABO incompatibility is no longer considered a contraindication for adult living donor liver transplantation (ALDLT) due to various strategies to overcome the ABO blood group barrier. We report the largest single-center experience of ABO-incompatible (ABOi) ALDLT in 235 adult patients. The desensitization protocol included a single dose of rituximab and total plasma exchange. In addition, local graft infusion therapy, cyclophosphamide, or splenectomy was used for a certain time period, but these treatments were eventually discontinued due to adverse events. There were three cases (1.3%) of in-hospital mortality. The cumulative 3-year graft and patient survival rates were 89.2% and 92.3%, respectively, and were comparable to those of the ABO-compatible group (n = 1301). Despite promising survival outcomes, 17 patients (7.2%) experienced antibody-mediated rejection that manifested as diffuse intrahepatic biliary stricture; six cases required retransplantation, and three patients died. ABOi ALDLT is a feasible method for expanding a living liver donor pool, but the efficacy of the desensitization protocol in targeting B cell immunity should be optimized.

Sequential vs simultaneous revascularization in patients undergoing liver transplantation: A meta-analysis

AIM

We undertook this meta-analysis to investigate the relationship between revascularization and outcomes after liver transplantation.

METHODS

A literature search was performed using MeSH and key words. The quality of the included studies was assessed using the Jadad Score and the Newcastle-Ottawa Scale. Heterogeneity was evaluated by the χ(2) and I (2) tests. The risk of publication bias was assessed using a funnel plot and Egger's test, and the risk of bias was assessed using a domain-based assessment tool. A sensitivity analysis was conducted by reanalyzing the data using different statistical approaches.

RESULTS

Six studies with a total of 467 patients were included. Ischemic-type biliary lesions were significantly reduced in the simultaneous revascularization group compared with the sequential revascularization group (OR = 4.97, 95%CI: 2.45-10.07; P < 0.00001), and intensive care unit (ICU) days were decreased (MD = 2.00, 95%CI: 0.55-3.45; P = 0.007) in the simultaneous revascularization group. Although warm ischemia time was prolonged in simultaneous revascularization group (MD = -25.84, 95%CI: -29.28-22.40; P < 0.00001), there were no significant differences in other outcomes between sequential and simultaneous revascularization groups. Assessment of the risk of bias showed that the methods of random sequence generation and blinding might have been a source of bias. The sensitivity analysis strengthened the reliability of the results of this meta-analysis.

CONCLUSION

The results of this study indicate that simultaneous revascularization in liver transplantation may reduce the incidence of ischemic-type biliary lesions and length of stay of patients in the ICU.

The impact of rituximab in ABO-incompatible pediatric living donor liver transplantation: the experience of a single center

Previous studies have demonstrated the safety of ABO-incompatible pediatric LDLT using preoperative plasmapheresis and rituximab; however, no reports have described the timing and dosage of rituximab administration for pediatric LDLT. This study aimed to describe a safe and effective dosage and timing of rituximab for patients undergoing pediatric ABO-incompatible LDLT based on the experience of our single center. A total of 192 LDLTs in 187 patients were examined. These cases included 29 ABO-incompatible LDLTs in 28 patients. Rituximab was used beginning in January 2004 in recipients older than two yr of age (first period: 375 mg/m(2) in two cases; second period: 50 mg/m(2) in two cases; and 200 mg/m(2) in eight cases). Two patients who received 375 mg/m(2) rituximab died of Pneumocystis carinii pneumonia and hemophagocytic syndrome. One patient who received 50 mg/m(2) rituximab required retransplantation as a consequence of antibody-mediated complications. All eight patients administered 200 mg/m(2) survived, and the mean CD20(+) lymphocyte count was 0.1% at the time of LDLT. In the preoperative management of patients undergoing pediatric ABO-incompatible LDLT, the administration of 200 mg/m(2) rituximab three wk prior to LDLT was safe and effective.

Biliary stricture is the only concern in ABO-incompatible adult living donor liver transplantation in the rituximab era

BACKGROUND & AIMS

With the introduction of rituximab prophylaxis, the survival of ABO-incompatible (ABOi) adult living donor liver transplant (ALDLT) has been strikingly improved due to the decreased incidence of antibody-mediated rejection. However, biliary stricture (BS) related to ABO incompatibility remains an unresolved concern.

METHODS

Excluding 105 dual graft ALDLTs, 1102 ALDLT cases including 142 ABOi recipients were included in this study. The desensitization protocol for overcoming the ABO blood group barrier comprised pretransplant plasma exchange, and rituximab (300-375 mg/m(2) BSA).

RESULTS

The mean follow-up period was 34.2 ± 15.4 months. The cumulative graft and patient survival rates were comparable in the two groups. The 1- and 3-year BS-free survival rates of ABOi ALDLT were 81.5 and 79.0%, respectively, lower than those of ABOc ALDLT (87.6 and 85.7%, respectively, p=0.022). In the risk factor analysis, diameter of graft bile duct opening <5mm, antecedent acute cellular rejection, and ABO incompatibility were independent risk factors for BS. Diffuse intrahepatic biliary stricture (DIHBS) exclusively occurred in 12 patients (8.5%) receiving ABOi ALDLT. The deaths of 3 patients and 4 cases of re-transplantation were related to DIHBS. Graft and patient survival rates were significantly reduced in ABOi ALDLT recipients with DIHBS. However, we failed to identify any significant risk factors for DIHBS.

CONCLUSIONS

The incidence of BS in ABOi ALDLT is higher than in ABOc, mainly due to the fact of DIHBS which significantly affected survival outcomes. To predict and prevent DIHBS, we need further studies to identify significant risk factors.

Beyond the Pediatric end-stage liver disease system: Solutions for infants with biliary atresia requiring liver transplant

Biliary atresia (BA), a chronic progressive cholestatic disease of infants, is the leading cause for liver transplant in children, especially in patients under two years of age. BA can be successfully treated with the Kasai portoenterostomy; however most patients still require a liver transplant, with up to one half of BA children needing a transplant by age two. In the current pediatric end-stage liver disease system, children with BA face the risk of not receiving a liver in a safe and timely manner. In this review, we discuss a number of possible solutions to help these children. We focus on two general approaches: (1) preventing/delaying need for transplantation, by optimizing the success of the Kasai operation; and (2) expediting transplantation when needed, by performing techniques other than the standard deceased-donor, whole, ABO-matched organ transplant.

Challenges in living donor liver transplantation

Living donor liver transplantation is a procedure that has waned in its application over the past decade but remains a beneficial procedure for properly selected candidates. This review discusses some of the newer, relevant studies in the field, focusing on outcomes with hepatocellular carcinoma, ABO-incompatible transplant, and issues in donor complications and safety.

ABO-Incompatible Living Donor Liver Transplantation from Hepatitis B Core Antibody Positive Donor to Hepatitis C Liver Cirrhosis Recipient: A Case Report

Herein, we describe an extremely rare experience of a patient with liver cirrhosis from hepatitis C virus (LC-HCV) who underwent an ABO-incompatible living donor liver transplantation (ABO-I-LDLT) using a hepatitis B core antibody (HBc-Ab) positive donor's liver graft. A 47-year-old Japanese woman with end stage LC-HCV, as a recipient, was preoperatively administered rituximab, mycophenolate mofetil, and steroids without plasma exchange. A routine ABO-I-LDLT procedure was applied using her daughter's HBc-Ab positive liver graft. Prophylaxis of the hepatitis B virus (HBV) infection using hepatitis B immunoglobulin (HBIG) and entecavir had been properly administered. Three months after the ABO-I-LDLT, HCV hepatitis relapsed. To date, this patient has been under antiviral therapy and prophylaxis of HBV infection using HBIG, while entecavir has been continued. The cognitions and techniques with regard to ABO-I-LDLT, prophylaxis of HBV cross infection, various patterns of immunosuppression, and antiviral therapy for HCV relapse are indispensable in managing a transplant recipient. According to the prophylaxis of HBV cross infection under ABO-I-LDLT, it may be very important to keep the HBs-Ab titer higher than usual for HBV naïve recipients, because severe systemic immunosuppression can cause de novo hepatitis.

Aetiology and risk factors of ischaemic cholangiopathy after liver transplantation

Liver transplantation (LT) is the best treatment for end-stage hepatic failure, with an excellent survival rates over the last decade. Biliary complications after LT pose a major challenge especially with the increasing number of procured organs after circulatory death. Ischaemic cholangiopathy (IC) is a set of disorders characterized by multiple diffuse strictures affecting the graft biliary system in the absence of hepatic artery thrombosis or stenosis. It commonly presents with cholestasis and cholangitis resulting in higher readmission rates, longer length of stay, repeated therapeutic interventions, and eventually re-transplantation with consequent effects on the patient’s quality of life and increased health care costs. The pathogenesis of IC is unclear and exhibits a higher prevalence with prolonged ischaemia time, donation after circulatory death (DCD), rejection, and cytomegalovirus infection. The majority of IC occurs within 12 mo after LT. Prolonged warm ischaemic times predispose to a profound injury with a subsequently higher prevalence of IC. Biliary complications and IC rates are between 16% and 29% in DCD grafts compared to between 3% and 17% in donation after brain death (DBD) grafts. The majority of ischaemic biliary lesions occur within 30 d in DCD compared to 90 d in DBD grafts following transplantation. However, there are many other risk factors for IC that should be considered. The benefits of DCD in expanding the donor pool are hindered by the higher incidence of IC with increased rates of re-transplantation. Careful donor selection and procurement might help to optimize the utilization of DCD grafts.

Long-term outcomes of children after solid organ transplantation

Solid organ transplantation has transformed the lives of many children and adults by providing treatment for patients with organ failure who would have otherwise succumbed to their disease. The first successful transplant in 1954 was a kidney transplant between identical twins, which circumvented the problem of rejection from MHC incompatibility. Further progress in solid organ transplantation was enabled by the discovery of immunosuppressive agents such as corticosteroids and azathioprine in the 1950s and ciclosporin in 1970. Today, solid organ transplantation is a conventional treatment with improved patient and allograft survival rates. However, the challenge that lies ahead is to extend allograft survival time while simultaneously reducing the side effects of immunosuppression. This is particularly important for children who have irreversible organ failure and may require multiple transplants. Pediatric transplant teams also need to improve patient quality of life at a time of physical, emotional and psychosocial development. This review will elaborate on the long-term outcomes of children after kidney, liver, heart, lung and intestinal transplantation. As mortality rates after transplantation have declined, there has emerged an increased focus on reducing longer-term morbidity with improved outcomes in optimizing cardiovascular risk, renal impairment, growth and quality of life. Data were obtained from a review of the literature and particularly from national registries and databases such as the North American Pediatric Renal Trials and Collaborative Studies for the kidney, SPLIT for liver, International Society for Heart and Lung Transplantation and UNOS for intestinal transplantation.

Predictive Factors for Reintubation following Noninvasive Ventilation in Patients with Respiratory Complications after Living Donor Liver Transplantation

Background

Postoperative respiratory complications are a major cause of mortality following liver transplantation (LT). Noninvasive ventilation (NIV) appears to be effective for respiratory complications in patients undergoing solid organ transplantation; however, mortality has been high in patients who experienced reintubation in spite of NIV therapy. The predictors of reintubation following NIV therapy after LT are not exactly known.

Methods

Of 511 adult patients who received living-donor LT, data on the 179 who were treated by NIV were retrospectively examined.

Results

Forty-three (24%) of the 179 patients who received NIV treatment required reintubation. Independent factors associated with reintubation by multivariate logistic regression analysis were controlled preoperative infections (odds ratio [OR] 8.88; 95% confidence interval (CI) 1.64 to 48.11; p = 0.01), ABO-incompatibility (OR 4.49; 95% CI, 1.50 to 13.38; p = 0.007), and presence of postoperative pneumonia at the time of starting NIV (OR 3.28; 95% CI, 1.02 to 11.01; p = 0.04). The reintubated patients had a significant higher rate of postoperative infectious complications and a significantly longer intensive care unit stay than those in whom NIV was successful (p<0.0001). Of the 43 reintubated patients, 22 (51.2%) died during hospitalization following LT vs. 8 (5.9%) of the 136 patients in whom NIV was successful (p<0.0001).

Conclusions

Because controlled preoperative infection, ABO-incompatibility or pneumonia prior to the start of NIV were independent risk factors for reintubation following NIV, caution should be used in applying NIV in patients with these conditions considering the high rate of mortality in patients requiring reintubation following NIV.

ABO-incompatible living donor liver transplantation is suitable in patients without ABO-matched donor

BACKGROUND & AIMS

ABO-incompatible liver transplantation is usually contraindicated because of the risk of antibody-mediated humoral rejection of the graft. We describe 22 successful cases of patients who had living donor liver transplantation (LDLT) from ABO-incompatible donors.

METHODS

The immunosuppressive protocol consisted of rituximab and plasmapheresis prior to LDLT. Plasmapheresis was planned for up to 2 weeks after LDLT aiming at maintaining levels of anti-ABO titers below 1:32.

RESULTS

The median age of recipients was 54 years and the median MELD score was 13. The initial range of isoagglutinin IgM and IgG titers were 1:8-1:1024 and 1:2-1:1024, respectively. Preoperative isoagglutinin IgM and IgG titers were achieved less than or equal to 1:8 by performing therapeutic plasma exchange (TPE). While the median number of TPE was 4 (range, 2-18) in all patients, it was 4 (range, 2-8) in the initial low titer group (<1:256) and 8 (range, 6-18) in the high titer group (≥ 1:256). There were no statistically significant differences for liver function tests in the first 2 weeks after transplantation between the groups having high MELD score (≥ 20) vs. low MELD score (<20), local graft infusion vs. systemic infusion, or high initial isoagglutinin titer (≥ 1:256) vs. low initial isoagglutinin titer (<1:256). Patient and graft survival was 100% and there was no acute humoral rejection in recipients at a mean follow-up of 10months (range, 3-21).

CONCLUSIONS

ABO-incompatible LDLT can be safely performed when rituximab and TPE are used, and may be proposed when ABO-compatible donors are not available.

Why does living donor liver transplantation flourish in Asia?

The success of liver transplantation worldwide has brought increased demand for the liver graft. Western and Asian countries have coped differently with the problems of the shortages in organ donation. In the West, efforts have focused on promoting deceased donor organ donation, whereas in Asia the focus has been on living donor liver transplantation (LDLT), as this procedure is more acceptable in most Asian cultures. LDLT, which was initially devised for paediatric liver transplant patients, has evolved from using a left lobe graft to a right lobe graft for an adult recipient. To widen the donor pool, dual grafts for a single recipient have been used in LDLT, and donors with hepatitis B core antibody positivity have been accepted, as well as ABO incompatible donors and recipients. The great advances in the field of LDLT have been dictated by the needs and the norms of Asian society. In this Perspectives article, we outline the reasons why LDLT flourishes in Asia.

Distribution of ABO blood group antibody titers in pediatric patients awaiting renal transplantation: implications for organ allocation policy

BACKGROUND

Blood group-incompatible transplantation is one strategy used when a potential recipient does not have a compatible living donor. Current practice includes desensitization strategies to reduce antibody titers. However, when antibodies are low, in cardiac transplantation in neonates for example, no desensitization is required. This study is the first to examine the distribution of ABO blood group antibody titers in a population of pediatric patients on the deceased-donor renal transplantation waiting list.

METHODS

All patients from two pediatric nephrology centers active on the national deceased-donor waiting list had antibody titers (total immunoglobulin load) measured. A simulation modeling the effect of allocating blood group-incompatible deceased-donor kidneys to those patients with titers of 16 or lower was developed.

RESULTS

Twenty-four children were screened; eight (33.3%) had titers of either anti-A or anti-B antibodies of 8 or lower. A further three (12.5%) had either an anti-A or anti-B antibody titer of 16. Blood group A or B patients had lower antibody levels than blood group O patients. In blood group O patients, levels of anti-A antibodies were higher than anti-B antibodies (Wilcoxon signed rank test, P=0.028). The simulation model showed that a change in organ allocation policy would increase pediatric transplant activity by 2.2% and reduce the median waiting time for a transplant.

CONCLUSION

This allocation strategy may be of particular benefit to those pediatric patients who have been on the deceased-donor waiting list for a long time or those with a high calculated reaction frequency.

Genetic, immunological and clinical risk factors for biliary strictures following liver transplantation

BACKGROUND

Biliary strictures after liver transplantation (LT) are a major cause of morbidity and reduced graft survival.

AIMS

The purpose of this study was to investigate genetic, immunological and clinical risk factors for the occurrence of post-LT ischaemic type biliary lesions (ITBLs) and biliary anastomotic strictures (AS).

METHODS

Clinical and laboratory data, chemokine receptor (CCR) genotypes, chemotactic cytokines and anti-major-histocompatibility complex antibodies in serum were investigated in 162 LT patients.

RESULTS

In the univariate analysis, older donor and recipient age, partial LT, high peak aspartate aminotransaminase (AST) levels and CC chemokine receptor 5 delta32 loss-of-function mutation (CCR5Δ32) were associated with ITBL, whereas LT for acute liver failure (ALF), ABO-compatible non-identical LT, presence of donor-specific anti-human leucocyte antigen (HLA) class II antibodies and fractalkine receptor (CX3CR1)-249II allele were associated with AS. In the multivariate analysis, CCR5Δ32 was an independent risk factor for ITBL, whereas LT for ALF, ABO-compatible non-identical LT, and CX3CR1-249II allele remained predictive for AS. Serum levels of interferon-gamma and interleukin (IL)-6 as well as IL-10 were significantly increased in patients with biliary strictures.

CONCLUSION

Specific chemokine receptor polymorphisms of the recipient are associated with development of post-LT biliary strictures. Altered cytokine profile may contribute to enhanced fibrotic tissue remodelling and biliary stricture formation. Screening of anti-HLA antibodies might be useful for early identification of at-risk patients who could benefit from closer surveillance and tailored immunosuppressive regimen. Our findings may have relevance for prediction and management of post-LT biliary strictures.

Emergency ABO-incompatible liver transplant secondary to fulminant hepatic failure: outcome, role of TPE and review of the literature

The increasing demand for solid organ transplants has brought to light the need to utilize organs in critical situations despite ABO-incompatibility. However, these transplantations are complicated by pre-existing ABO antibodies which may be potentially dangerous and makes the transplantation prone to failure due to rejection with resulting necrosis or intrahepatic biliary complications. We report the clinical outcome of an emergency ABO-incompatible liver transplant (due to fulminant hepatic failure with sudden and rapidly deteriorating mental status) using a modified therapeutic plasma exchange (TPE) protocol. The recipient was O-positive with an initial anti-B titer of 64 and the cadaveric organ was from a B-positive donor. The patient underwent initial TPE during the peri-operative period, followed by a series of postoperative daily TPE, and later a third series of TPE for presumptive antibody-mediated rejection. The latter two were performed in conjunction with the use of IVIg and rituximab. The recipient's anti-B titer was reduced and maintained at 8 or less 8 months post-op. However, an elevation of transaminases 3 months post-transplant triggered a biopsy which was consistent with cellular rejection and with weak C4d positive staining suggestive of antibody mediated rejection. Additional plasma exchange procedures were performed. The patient improved rapidly after modification of her immunosuppression regimen and treatment with plasma exchange. This case illustrates that prompt and aggressive plasma exchange, in conjunction with immunosuppression, is a viable approach to prevent and treat antibody mediated transplant rejection in emergency ABO-incompatible liver transplant.

Ischemia-Reperfusion Injury and Ischemic-Type Biliary Lesions following Liver Transplantation

Ischemia-reperfusion (I-R) injury after liver transplantation (LT) induces intra- and/or extrahepatic nonanastomotic ischemic-type biliary lesions (ITBLs). Subsequent bile duct stricture is a significant cause of morbidity and even mortality in patients who underwent LT. Although the pathogenesis of ITBLs is multifactorial, there are three main interconnected mechanisms responsible for their formation: cold and warm I-R injury, injury induced by cytotoxic bile salts, and immunological-mediated injury. Cold and warm ischemic insult can induce direct injury to the cholangiocytes and/or damage to the arterioles of the peribiliary vascular plexus, which in turn leads to apoptosis and necrosis of the cholangiocytes. Liver grafts from suboptimal or extended-criteria donors are more susceptible to cold and warm I-R injury and develop more easily ITBLs than normal livers. This paper, focusing on liver I-R injury, reviews the risk factors and mechanisms leading to ITBLs following LT.

Decreased risk of graft failure with maternal liver transplantation in patients with biliary atresia

The presence of maternal cells in offspring may promote tolerance to noninherited maternal antigens (NIMAs). Children with biliary atresia (BA) have increased maternal cells in their livers, which may impact tolerance. We hypothesized that patients with BA would have improved outcomes when receiving a maternal liver. We reviewed all pediatric liver transplants recorded in the SRTR database from 1996 to 2010 and compared BA and non-BA recipients of maternal livers with recipients of paternal livers for the incidences of graft failure and retransplantation. Rejection episodes after parental liver transplantation were examined for patients transplanted at our institution. BA patients receiving a maternal graft had lower rates of graft failure compared to those receiving a paternal graft (3.7% vs. 10.5%, p = 0.02) and, consequently, fewer episodes of retransplantation (2.7% vs. 7.5%, p = 0.04). These differences were not seen among non-BA patients or among BA patients who received female deceased donor grafts. In patients transplanted at our institution, paternal liver transplantation was associated with an increased incidence of refractory rejection compared to maternal liver transplantation only in BA. Our data support the concept that maternal cells in BA recipients promote tolerance to NIMAs and may be important in counseling BA patients who require liver transplantation.

ABO-incompatible pediatric liver transplantation in very small recipients: Birmingham's experience

Liver transplantation (LT) for very small recipients is challenging but in experienced centres, good results can be achieved. Despite the risk of antibody-mediated acute rejection, some studies have demonstrated the safety of ABO incompatible liver transplantation (ILT) in children and particularly in infants. The aim of our study was to describe the outcome of liver transplantation in infants <5 kg and the safety of using ILT in this group. All LT performed between 1991 and 2010 in children <5 kg were reviewed. Twenty-nine patients were included, five of whom had an ILT. Acute liver failure was encountered in 20 cases. The recipient age and weight at transplantation were respectively 63 days (range: 14-268 days) and 4 kg (range: 2.4-5 kg). The graft-to-recipient ratio was 6.1% (range 2.3-9%). An aortic conduit and delayed abdominal closure were used respectively in 76% and 81% of the procedures. The ABO compatible liver transplantation (CLT) and ILT groups were similar regarding recipient's demographics, graft types or technical transplantation data. The one- and five-yr patient and graft survival were respectively 62%, 62% and 62%, 57.9% with a median follow-up of 95 months. Vascular complications occurred in six cases (21.4%) and biliary complications were encountered in five patients (17%). Acute and chronic rejection developed respectively in 37% and 26% of the recipients. The five patients undergoing ILT are all alive without graft lost after a median follow-up of 34 months (range 7-55 months). When compared with the CLT group, no significant differences were found regarding patient or graft survival, vascular or biliary complications and rejection rates. In our experience, ILT in small infants has short and long term outcomes comparable to ABO-compatible grafts and excellent results can be achieved with a standard immunosuppressive protocol. To avoid mortality on the waiting list for neonatal recipients, ABO-incompatible liver grafts can be used safely.