Identifying independent risk factors for graft loss after primary liver transplantation

Effects of CYP3A5 Genotypes on Thrombocytopenia in Liver Transplantation Patients Treated with Tacrolimus

BACKGROUND

Thrombocytopenia is a complication after liver transplantation. This study's aims were to evaluate the role of CYP3A5 genotypes on tacrolimus-induced thrombocytopenia after orthotopic liver transplantation.

METHODS

In this retrospective case-control study, data from 100 patients who underwent deceased-donor liver transplantation (DDLT) were divided into CYP3A5*3 genotype (donor/recipient) tacrolimus fast- (A*/A*, n = 22), intermediate- (A*/GG, n = 20; GG/A*, n = 31) and slow-metabolizer (GG/GG, n = 27) groups. Platelet count changes and prognosis for 180 days after surgery were compared.

RESULTS

Platelet counts declined significantly after DDLT, especially on postoperative day (POD) 3, and continued at low levels for a week thereafter in all groups. In the GG/GG group, platelet counts on POD3 (50.29 ± 5.44 × 109/L) were the lowest among the groups (A*/A*, 71.00 ± 6.22 × 109/L; A*/GG, 57.95 ± 6.21 × 109/L; GG/A*, 75.90 ± 5.56 × 109/L) (p = 0.006). Compared with the A*/A* genotype, tacrolimus nadir levels were significantly higher in GG/GG genotype patients, who also exhibited a higher incidence of hemorrhage (22.2%, p = 0.011). A combination of a nadir blood concentration of tacrolimus ≥ 4.74 ng/mL and spleen size ≥ 165.5 mm was a risk factor for increased thrombocytopenia after DDLT on POD3, with an AUC of 0.735 (sensitivity, 77.2%; specificity, 41.7%).

CONCLUSIONS

A high blood concentration of tacrolimus after the early stage of DDLT is a major risk factor for hemorrhage. For the CYP3A5 genotype (GG/GG), controlling the blood concentration of tacrolimus below the target concentration until POD3 can avoid thrombocytopenia-related complications.

Gamma-glutamyltransferase predicts macrovesicular liver graft steatosis - an analysis of discarded liver allografts in Finland

OBJECTIVE

Liver-transplantation activity is limited by the shortage of grafts. Donor-liver macrovesicular steatosis predisposes to ischemia-reperfusion injury and is associated with reduced graft survival. The increasing prevalence of fatty-liver disease underlines the importance of identifying macrovesicular steatosis in potential donor livers. We analyzed liver grafts discarded for transplantation, and particularly the role of gamma-glutamyltransferase (GGT) in predicting graft steatosis.

METHODS

One-hundred sixty rejected cadaveric-donor liver grafts were studied. Donor selection was based on clinical data, and macroscopic graft inspection. Discarded grafts were biopsied at procurement of non-liver organs.

RESULTS

The most common reasons for discarding the graft were abnormal liver tests, ultrasound-verified steatosis and history of harmful alcohol use. GGT correlated moderately with macrovesicular steatosis (r = 0.52, p < 0.001), but poorly with microvesicular steatosis (r = 0.36, p < 0.001). Increased correlation between GGT and macrovesicular steatosis was observed among alcohol abusers (r = 0.67, p < 0.001). Area under the curve (AUC) of GGT for predicting >30% macrovesicular steatosis was 0.79 (95% CI 0.71-0.88), and for >60% steatosis, 0.79 (95% CI 0.68-0.90). The optimal GGT-cut off for detecting >30% and >60% macrovesicular steatosis were, respectively, 66 U/L (sensitivity 76% and specificity 68%) and 142 U/L (sensitivity 66% and specificity 83%). Among alcohol users, a GGT value >90 U/L showed 100% sensitivity for >60% macrovesicular steatosis. AUC for GGT in predicting fibrosis Stages 2-4 was 0.82 (95% CI 0.71-0.92, p < 0.001, optimal cut off 68, sensitivity 92%, specificity 61%).

CONCLUSIONS

Abnormal liver values, steatosis and harmful alcohol use were the main reasons for discarding liver-graft offers in Finland. GGT proved useful in predicting moderate and severe liver graft macrovesicular steatosis.

Dualistic role of platelets in living donor liver transplantation: Are they harmful?

Platelets are anucleate fragments mainly involved in hemostasis and thrombosis, and there is emerging evidence that platelets have other nonhemostatic potentials in inflammation, angiogenesis, regeneration and ischemia/reperfusion injury (I/R injury), which are involved in the physiological and pathological processes during living donor liver transplantation (LDLT). LDLT is sometimes associated with impaired regeneration and severe I/R injury, leading to postoperative complications and decreased patient survival. Recent studies have suggested that perioperative thrombocytopenia is associated with poor graft regeneration and postoperative morbidity in the short and long term after LDLT. Although it is not fully understood whether thrombocytopenia is the cause or result, increasing platelet counts are frequently suggested to improve posttransplant outcomes in clinical studies. Based on rodent experiments, previous studies have identified that platelets stimulate liver regeneration after partial hepatectomy. However, the role of platelets in LDLT is controversial, as platelets are supposed to aggravate I/R injury in the liver. Recently, a rat model of partial liver transplantation (LT) was used to demonstrate that thrombopoietin-induced thrombocytosis prior to surgery accelerated graft regeneration and improved the survival rate after transplantation. It was clarified that platelet-derived liver regeneration outweighed the associated risk of I/R injury after partial LT. Clinical strategies to increase perioperative platelet counts, such as thrombopoietin, thrombopoietin receptor agonist and platelet transfusion, may improve graft regeneration and survival after LDLT.

Assessment of Donor Liver Pathology Predicts Survival After Liver Transplantation: A Retrospective Cohort Study

BACKGROUND

The aims of this study were to investigate the pathologic manifestation of pretransplant biopsy and to provide an accurate assessment method for liver graft of China Donation after Citizen's Death (CDCD).

METHODS

A retrospective analysis was performed based on clinical and biopsy data of 96 CDCD liver transplantations completed between January 2012 and December 2017. The pretransplant pathologic sections were semiquantitatively scored according to Banff Schema recommendations on liver allograft pathology. Graft overall survival (OS) and early allograft dysfunction (EAD) rates were observed.

RESULTS

The histologic analysis of the 96 CDCD liver graft biopsy specimens was summarized, including portal area neutrophilic infiltrate, macrovesicular steatosis, microvesicular steatosis, and hepatocellular swelling. Among these pathologic characteristics, only portal area neutrophilic infiltrate ≥20% was an independent risk factor for graft survival, although it has limited effect on the recipient's short-term prognosis.

CONCLUSIONS

We found that portal area neutrophilic infiltrate ≥20% was an independent risk factors for long-term graft survival. According to this criterion, we can identify liver transplant recipients at risk for poor prognosis and make timely interventions.

Meta-analysis and systematic review: Prevalence, graft failure, mortality, and post-operative thrombosis in liver transplant recipients with pre-operative portal vein thrombosis

AIMS

This study seeks to evaluate the association between pre-transplant portal vein thrombosis (PVT) and overall survival, graft failure, waitlist mortality, and post-operative PVT after liver transplantation.

METHODS

A conventional pairwise meta-analysis between patients with and without pre-transplant PVT was conducted using hazard ratios or odds ratios where appropriate.

RESULTS

Prevalence of preoperative PVT was 11.6% (CI 9.70-13.7%). Pre-operative PVT was associated with increased overall mortality (HR 1.45, 95% CI 1.27-1.65) and graft loss (HR 1.58, 95% CI 1.34-1.85). In particular, grade 3 (HR 1.59, 95% CI 1.00-2.51) and 4 (HR 2.24, 95% CI 1.45-3.45) PVT significantly increased mortality, but not grade 1 or 2 PVT. Patients with PVT receiving living donor (HR 1.54, 95% CI 1.24-1.91) and deceased donor (HR 1.52, 95% CI 1.21-1.92) liver transplantation had increased mortality, with no significant difference between transplant types (P = .13). Furthermore, pre-transplant PVT was associated with higher occurrence of post-transplant PVT (OR 5.06, 95% CI 3.89-6.57). Waitlist mortality was not significantly increased in patients with pre-transplant PVT.

CONCLUSION

Graft failure, mortality, and post-operative PVT are more common in pre-transplant PVT patients, especially in grade 3 or 4 PVT. Prophylactic anticoagulation can be considered to reduce re-thrombosis and improve survival.

Outcomes after liver transplantation in Korea: Incidence and risk factors from Korean transplantation registry

BACKGROUND/AIMS

To analyze the incidence and risk factors of outcomes after liver transplantation (LT) in the Korean population.

METHODS

This study analyzed data from the liver cohort of Korean Organ Transplantation Registry (KOTRY) who had LT between May 2014 and December 2017. Study measures included the incidence of post-LT outcomes in recipients of living donor LT (LDLT) and deceased donor LT (DDLT). Cox multivariate proportional hazards model was used to determine the potential risk factors predicting the outcomes.

RESULTS

A total of 2,563 adult recipients with LT (LDLT, n=1,956; DDLT, n=607) were included, with mean±standard deviation age of 53.9±8.9 years, and 72.2% were male. The post-LT outcomes observed in each LDLT and DDLT recipients were death (4.0% and 14.7%), graft loss (5.0% and 16.1%), rejection (7.0% and 12.0%), renal failure (2.7% and 13.8%), new onset of diabetes (12.5% and 15.4%), and hepatocellular carcinoma (HCC) recurrence (both 6.7%). In both LDLT and DDLT recipients, the most common post-LT complications were renal dysfunction (33.6% and 51.4%), infection (26.7% and 48.4%), and surgical complication (22.5% and 23.9%). Incidence of these outcomes were generally higher among recipients of DDLT than LDLT. Multivariate analysis indicated recipient age and DDLT as significant risk factors associated with death and graft loss. DDLT and ABO incompatible transplant were prognostic factors for rejection, and HCC beyond Milan criteria at pre-transplant was a strong predictor of HCC recurrence.

CONCLUSION

This study is a good indicator of the post-LT prognosis in the Korean population and suggests a significant burden of post-LT complications.

Low Postoperative Platelet Counts Are Associated with Major Morbidity and Inferior Survival in Adult Recipients of Orthotopic Liver Transplantation

BACKGROUND

Platelets (PLT) play an essential functional role in cellular injury and liver regeneration following partial hepatectomy and orthotopic liver transplantation (OLT). Here, we investigated the association of postoperative PLT counts with short- and long-term outcomes in adult OLT recipients.

METHODS

Three hundred consecutive patients from our prospective OLT database were analyzed retrospectively (May 2010-November 2017). Ninety-day post-OLT complications were graded using the Clavien-Dindo (CD) classification and quantified by the comprehensive complication index (CCI). To determine the prognostic accuracy of PLT counts, the area under the receiver operating characteristic curve (AUROC) was calculated for major complications (CD ≥ 3b). Parametric and non-parametric tests were applied for subgroup analyses. Uni- and multivariable logistic regression analyses were performed to identify risk factors for major complications. Graft and patient survival were analyzed using the Kaplan-Meier method as well as uni- and multivariable Cox regression analyses.

RESULTS

Postoperative day 6 PLT counts < 70 × 10⁹/L (POD6-70) were identified as the best cutoff for predicting major complications (AUROC = 0.7; p < 0.001; Youden index 0.317). The stratification of patients into low- (n = 113) and high-PLT (n = 187) groups highlighted significant differences in major complications (CCI 68 ± 29 vs. 43 ± 28, p < 0.001); length of hospital and intensive care unit (ICU) stay (53 ± 43 vs. 31 ± 25, p < 0.001; 21 ± 29 vs. 7 ± 11, p < 0.001, respectively) and estimated procedural costs. POD6-70 was associated with inferior 5-year graft survival. Multivariable logistic regression analysis identified POD6-70 as an independent predictor of major complications (odds ratio 2.298, confidence intervals 1.179-4.478, p = 0.015).

CONCLUSION

In OLT patients, a PLT count on POD6 of less than 70 × 10⁹/L bears a prognostic significance warranting further investigations.

Platelet and liver regeneration after liver surgery

The success of liver surgery, including resection and transplantation, is largely dependent on the ability of the liver to regenerate. Despite substantial improvement in surgical techniques and perioperative care, one of the main concerns is post-hepatectomy liver failure and early allograft dysfunction, both of which are associated with impaired liver regeneration. Recent studies have demonstrated the positive role of platelets in promoting liver regeneration and protecting hepatocytes; however, the underlying mechanisms responsible for these effects are not fully understood. In this review, we updated the accumulated evidence of the role of platelets in promoting liver regeneration, with a focus on liver resection and liver transplantation. The goal of these studies was to support the clinical implementation of platelet agents, such as thrombopoietin receptor agonists, to augment liver regeneration after liver surgery. This "platelet therapy" may become a treatment choice for post-hepatectomy liver failure and early allograft dysfunction.

Perioperative intensive glycemic control for liver transplant recipients to prevent surgical site infection: A systematic review and meta-analysis

BACKGROUND

Surgical Site Infections (SSIs) are common among liver transplant recipients and result in adverse patient outcomes. Standard glycemic control is effective in reducing SSIs. Some studies suggest intensive glycemic control reduces the risk of SSI further.

METHODS

For this systematic review, were searched for studies comparing perioperative intensive and standard glycemic control in liver transplant recipients. Clinical trials registries and reference lists of included studies were also searched. No date or language restrictions were applied. Randomized controlled trials (RCTs) were assessed using Cochrane risk of bias tool and GRADE method. Cohort studies were assessed using the Newcastle-Ottawa Scale.

RESULTS

Two RCTs and three cohort studies met the inclusion criteria. Low-quality evidence from the two RCTs in a meta-analysis with 264 recipients found it was uncertain whether the risk of SSI was reduced by having intensive glycemic control (Risk Ratio [RR] 1.52, 95% CI 0.66-3.51). However, there was an increased risk of hypoglycemia among recipients having intensive glycemic control (RR 2.34, 95% CI 1.40-3.92) n = 264. Meta-analyses found it uncertain whether secondary outcomes, allograft rejection and death, were reduced among recipients having intensive glycemic control; (RR 0.85, 95% CI 0.48-1.50) and (RR 0.92, 95% CI 0.44-1.95), respectively. The two cohort studies were poor quality and presented conflicting outcomes on the effects of intensive blood glucose control on SSI.

CONCLUSION

There is insufficient evidence to recommend the use of intensive glycemic control among liver transplant recipients to reduce SSIs.

Improved Survival in Liver Transplant Patients Receiving Prolonged-release Tacrolimus-based Immunosuppression in the European Liver Transplant Registry (ELTR): An Extension Study

BACKGROUND

We compared, through the European Liver Transplant Registry, long-term liver transplantation outcomes with prolonged-release tacrolimus (PR-T) versus immediate-release tacrolimus (IR-T)-based immunosuppression. This retrospective analysis comprises up to 8-year data collected between 2008 and 2016, in an extension of our previously published study.

METHODS

Patients with <1 month follow-up were excluded; patients were propensity score matched for baseline characteristics. Efficacy measures included: univariate/multivariate analyses of risk factors influencing graft/patient survival up to 8 years posttransplantation, and graft/patient survival up to 4 years with PR-T versus IR-T. Overall, 13 088 patients were included from 44 European centers; propensity score-matched analyses comprised 3006 patients (PR-T: n = 1002; IR-T: n = 2004).

RESULTS

In multivariate analyses, IR-T-based immunosuppression was associated with reduced graft survival (risk ratio, 1.49; P = 0.0038) and patient survival (risk ratio, 1.40; P = 0.0215). There was improvement with PR-T versus IR-T in graft survival (83% versus 77% at 4 y, respectively; P = 0.005) and patient survival (85% versus 80%; P = 0.017). Patients converted from IR-T to PR-T after 1 month had a higher graft survival rate than patients receiving IR-T at last follow-up (P < 0.001), or started and maintained on PR-T (P = 0.019). One graft loss in 4 years was avoided for every 14.3 patients treated with PR-T versus IR-T.

CONCLUSIONS

PR-T-based immunosuppression might improve long-term outcomes in liver transplant recipients than IR-T-based immunosuppression.

Intraoperative Hypertension and Thrombocytopenia Associated With Intracranial Hemorrhage After Liver Transplantation

BACKGROUND

Intracranial hemorrhage (ICH) is a devastating complication. Although hypertension and thrombocytopenia are well-known risk factors for ICH in the general population, their roles in ICH after liver transplantation (LT) have not been well established.

METHODS

We performed a retrospective study and hypothesized that intraoperative hypertension and thrombocytopenia were associated with posttransplant ICH. New onset of spontaneous hemorrhage in the central nervous system within 30 days after LT were identified by reviewing radiologic reports and medical records. Risk factors were identified by multivariate logistic regression. Receiver operating characteristic analysis and Youden index were used to find the cutoff value with optimal sensitivity and specificity.

RESULTS

Of 1836 adult patients undergoing LT at University of California, Los Angeles, 36 (2.0%) developed ICH within 30 days after LT. Multivariate logistic regression demonstrated that intraoperative mean arterial pressure ≥105 mm Hg (≥10 min) (odds ratio, 6.5; 95% confidence interval, 2.7-7.7; P < 0.001) and platelet counts ≤30 × 10/L (odds ratio, 3.3; 95% confidence interval, 14-7.7; P = 0.006) were associated with increased risk of postoperative ICH. Preoperative total bilirubin ≥7 mg/dL was also a risk factor. Thirty-day mortality in ICH patients was 48.3%, significantly higher compared with the non-ICH group (3.0%; P < 0.001). Patients with all 3 risk factors had a 16% chance of developing ICH.

CONCLUSIONS

In the current study, postoperative ICH was uncommon but associated with high mortality. Prolonged intraoperative hypertension and severe thrombocytopenia were associated with postoperative ICH. More studies are warranted to confirm our findings and develop a strategy to prevent this devastating posttransplant complication.

Assessment of Liver Graft Steatosis: Where Do We Stand?

The growing number of patients on waiting lists for liver transplantation and the shortage of organs have forced many centers to adopt extended criteria for graft selection, moving the limit of acceptance for marginal livers. Steatotic grafts that were, in the past, considered strictly unacceptable for transplantation because of the high risk of early nonfunction are now considered as a potential resource for organ implementation. Several methods to diagnose, measure, classify, and stage steatosis exist, but none can be considered qualitatively and quantitatively "the ideal method" to date. Clinical, biological, and imaging data can be very helpful to estimate graft steatosis, but histology still remains the gold standard. There is an increasing need for rapid and reliable tools to assess graft steatosis. Herein, we present a comprehensive review of the approaches that are currently used to quantify steatosis in liver grafts.

The impact of major extended donor criteria on graft failure and patient mortality after liver transplantation

INTRODUCTION

Numerous extended donor criteria (EDC) have been identified in liver transplantation (LT), but different EDC have different impacts on graft and patient survival. This study aimed to identify major EDC (maEDC) that were best able to predict the outcome after LT and to examine the plausibility of an allocation algorithm based on these criteria.

METHODS

All consecutive LTs between 12/2006 and 03/2014 were included (n = 611). We analyzed the following EDC: donor age > 65 years, body mass index > 30, malignancy and drug abuse history, intensive care unit stay/ventilation > 7 days, aminotransferases > 3 times normal, serum bilirubin > 3 mg/dL, serum Na⁺ > 165 mmol/L, positive hepatitis serology, biopsy-proven macrovesicular steatosis (BPS) > 40%, and cold ischemia time (CIT) > 14 h. We analyzed hazard risk ratios of graft failure for each EDC and evaluated primary non-function (PNF). In addition, we analyzed 30-day, 90-day, 1-year, and 3-year graft survival. We established low- and high-risk graft (maEDC 0 vs. ≥ 1) and recipient (labMELD < 20 vs. ≥ 20) groups and compared the post-LT outcomes between these groups.

RESULTS

BPS > 40%, donor age > 65 years, and CIT > 14 h (all p < 0.05) were independent predictors of graft failure and patient mortality and increased PNF, 30-day, 90-day, 1-year, and 3-year graft failure rates. Three-year graft and patient survival decreased in recipients of ≥ 1 maEDC grafts (all p < 0.05) and LT of high-risk grafts into high-risk recipients yielded worse outcomes compared with other groups.

CONCLUSION

Donor age > 65 years, BPS > 40%, and CIT > 14 h are major EDC that decrease short and 3-year graft survival, and 3-year patient survival. An allocation algorithm based on maEDC and labMELD is therefore plausible.

Thrombocytopenia after liver transplantation: Should we care?

Transient thrombocytopenia is a common phenomenon after liver transplantation. After liver transplantation (LT), platelet count decreases and reaches a nadir on postoperative days 3-5, with an average reduction in platelet counts of 60%; platelet count recovers to preoperative levels approximately two weeks after LT. The putative mechanisms include haemodilution, decreased platelet production, increased sequestration, medications, infections, thrombosis, or combination of these processes. However, the precise mechanisms remain unclear. The role of platelets in liver transplantation has been highlighted in recent years, and particular attention has been given to their effects beyond hemostasis and thrombosis. Previous studies have demonstrated that perioperative thrombocytopenia causes poor graft regeneration, increases the incidence of postoperative morbidity, and deteriorates the graft and decreases patient survival in both the short and long term after liver transplantation. Platelet therapies to increase perioperative platelet counts, such as thrombopoietin, thrombopoietin receptor agonist, platelet transfusion, splenectomy, and intravenous immunoglobulin treatment might have a potential for improving graft survival, however clinical trials are lacking. Further studies are warranted to detect direct evidence on whether thrombocytopenia is the cause or result of poor-graft function and postoperative complications, and to determine who needs platelet therapies in order to prevent postoperative complications and thus improve post-transplant outcomes.

MiR-544 promotes immune escape through downregulation of NCR1/NKp46 via targeting RUNX3 in liver cancer

Objective

To study the potential role of miR-544 in the immune escape mechanism of hepatoma cells.

Methods

Natural killer (NK) cells were collected from healthy volunteers and patients with liver cancer. Interleukin (IL)-2 activated-NK-92 cells were transfected with miR-544 inhibitor/mimic or NC/pre-NC in HepG2 co-culture system. NK-92 cells were treated with control, IL-2, IL-2 + pre-NC, IL-2 + miR-544 mimic, IL-2 + miR-544 mimic + pcDNA and IL-2 + miR-544 mimic + pcDNA-runt-related transcription factor 3 (RUNX3) groups. Mice models of liver cancer were well established. Expression of miR-544, natural cytotoxicity receptor 1 (NCR1) and RUNX3 were evaluated by quantitative real-time PCR and western blotting. Flow cytometry and ELISA were used to determine NK cell cytotoxicity and the levels of INF-γ, respectively.

Results

MiR-544 was upregulated while NCR1 and RUNX3 was downregulated in NK cells of patients with liver cancer. The levels of IFN-γ and miR-544 expression were increased and decreased in IL-2 activated-NK cells, respectively. Inversely, miR-544 overexpression inhibited NK cell cytotoxicity by downregulating IFN-γ. However, miR-544 directly targeted RUNX3 and negatively regulated NCR1. Furthermore, miR-544 promoted immune escape of hepatoma cells in vivo and in vitro.

Conclusion

miR-544 promoted the immune escape of liver cancer cells by downregulating NCR1 via targeting RUNX3.

Grade of donor liver microvesicular steatosis does not affect the postoperative outcome after liver transplantation

BACKGROUND

The potential effect of graft steatosis on the postoperative liver function is discussed controversially. The present study aimed to evaluate the effect of the donor liver microvesicular steatosis on the postoperative outcome after liver transplantation.

METHODS

Ninety-four patients undergoing liver transplantation at the University Hospital Aachen were included in this study. The patient cohort was divided into three groups according to the grade of microvesicular steatosis (MiS): MiS <30% (n=27), MiS 30%-60% (n=41) and MiS >60% (n=26). The outcomes after liver transplantation were evaluated, including the 30-day and 1-year patient and graft survival rates and the incidences of early allograft dysfunction (EAD) and primary nonfunction (PNF).

RESULTS

The incidences of EAD and PNF did not differ significantly between the groups. We observed 5 cases of PNF, one occurred in the MiS <30% group and 4 in the MiS 30%-60% group. The 30-day and 1-year graft survivals did not differ significantly between groups. The 30-day patient survival rates were 100% in all groups. The 1-year patient survival rates were 94.4% in the MiS <30% group, 87.9% in the MiS 30%-60% group and 90.9% in the MiS >60% group.

CONCLUSION

Microvesicular steatosis of donor livers has no negative effect on the postoperative outcome after liver transplantation.