Comparing indications, complexity and outcomes of laparoscopic liver resection between centers with and without a liver transplant program: a French nationwide study.

BACKGROUND: There are no data to evaluate the difference in populations and impact of centers with liver transplant programs in performing laparoscopic liver resection (LLR). METHODS: This was a multicenter study including patients undergoing LLR for benign and malignant tumors at 27 French centers from 1996 to 2018. The main outcomes were postoperative severe morbidity and mortality. RESULTS: A total of 3154 patients were included, and 14 centers were classified as transplant centers (N = 2167 patients, 68.7 %). The transplant centers performed more difficult LLRs and more resections for hepatocellular carcinoma (HCC) in patients who more frequently had cirrhosis. A higher rate of performing the Pringle maneuver, a lower rate of blood loss and a higher rate of open conversion (all p < 0.05) were observed in the transplant centers. There was no association between the presence of a liver transplant program and either postoperative severe morbidity (<10 % in each group; p = 0.228) or mortality (1 % in each group; p = 0.915). CONCLUSIONS: Most HCCs, difficult LLRs, and cirrhotic patients are treated in transplant centers. We show that all centers can achieve comparable safety and quality of care in LLR independent of the presence of a liver transplant program.

Area under the curve of tacrolimus using microsampling devices: towards precision medicine in solid organ transplantation?

PURPOSE: Therapeutic drug monitoring of tacrolimus using trough concentration (Cmin) is mandatory to ensure drug efficacy and safety in solid organ transplantation. However, Cmin is just a proxy for the area under the curve of drug concentrations (AUC) which is the best pharmacokinetic parameter for exposure evaluation. Some studies suggest that patients may present discrepancies between these two parameters. AUC is now easily available through mini-invasive microsampling approach. The aim of this study is to evaluate the relationship between AUC and Cmin in patients benefiting from a complete pharmacokinetic profile using a microsampling approach. METHODS: Fifty-one transplant recipients benefited from a complete pharmacokinetic profile using a microsampling approach, and their 24-h AUC were calculated using the trapezoidal method. The correlation with Cmin was then explored. In parallel, we estimated AUC using the sole Cmin and regression equations according to the post-transplantation days and the galenic form. RESULTS: Weak correlations were found between 24-h AUC observed and the corresponding Cmin (R2 = 0.60) and between AUC observed and expected using the sole Cmin (R2 = 0.62). Therapeutic drug monitoring of tacrolimus using Cmin leads to over- or under-estimate drug exposure in 40.3% of patients. CONCLUSION: Tacrolimus Cmin appears to be an imperfect reflection of drug exposure. Evaluating AUC using a microsampling approach offers a mini-invasive strategy to monitor tacrolimus treatment in transplant recipients.

[Surgical aspects of multi-organ harvesting for transplantation]. / Aspects chirurgicaux du prélèvement multiorganes en vue de greffes.

The aim of multi-organ harvesting is to remove and condition organs so that they can be transplanted. It is an extremely well codified surgical procedure, performed in a precise order. It is unique in that it involves different teams, each with its own specialization.

End-ischemic hypothermic oxygenated perfusion for extended criteria donors in liver transplantation: a multicenter, randomized controlled trial-HOPExt.

BACKGROUND: Given the scarce donor supply, an increasing number of so-called marginal or extended criteria donor (ECD) organs are used for liver transplantation. These ECD liver grafts are however known to be associated with a higher rate of early allograft dysfunction and primary non-function because of a greater vulnerability to ischemia-reperfusion injury. The end-ischemic hypothermic oxygenated machine perfusion (HOPE) technique may improve outcomes of liver transplantation with ECD grafts by decreasing reperfusion injury. METHODS: HOPExt trial is a comparative open-label, multicenter, national, prospective, randomized, controlled study, in two parallel groups, using static cold storage, the gold standard procedure, as control. The trial will enroll adult patients on the transplant waiting list for liver failure or liver cirrhosis and/or liver malignancy requiring liver transplantation and receiving an ECD liver graft from a brain-dead donor. In the experimental group, ECD liver grafts will first undergo a classical static cold (4 °C) storage followed by a hypothermic oxygenated perfusion (HOPE) for a period of 1 to 4 h. The control group will consist of the classic static cold storage which is the gold standard procedure in liver transplantation. The primary objective of this trial is to study the efficacy of HOPE used before transplantation of ECD liver grafts from brain-dead donors in reducing postoperative early allograft dysfunction within the first 7 postoperative days compared to simple cold static storage. DISCUSSION: We present in this protocol all study procedures in regard to the achievement of the HOPExt trial, to prevent biased analysis of trial outcomes and improve the transparency of the trial results. Enrollment of patients in the HOPExt trial has started on September 10, 2019, and is ongoing. TRIAL REGISTRATION: ClinicalTrials.gov NCT03929523. Registered on April 29, 2019, before the start of inclusion.

Role of neoadjuvant chemoradiotherapy in liver transplantation for unresectable perihilar cholangiocarcinoma: multicentre, retrospective cohort study.

BACKGROUND: The Mayo protocol for liver transplantation in patients with unresectable perihilar cholangiocarcinoma is based on strict selection and neoadjuvant chemoradiotherapy. The role of neoadjuvant chemoradiotherapy in this scenario remains unclear. The aim of this study was to compare outcomes after transplantation for perihilar cholangiocarcinoma using strict selection criteria, either with or without neoadjuvant chemoradiotherapy. METHODS: This was an international, multicentre, retrospective cohort study of patients who underwent transplantation between 2011 and 2020 for unresectable perihilar cholangiocarcinoma using the Mayo selection criteria and receiving neoadjuvant chemoradiotherapy or not receiving neoadjuvant chemoradiotherapy. Endpoints were post-transplant survival, post-transplant morbidity rate, and time to recurrence. RESULTS: Of 49 patients who underwent liver transplantation for perihilar cholangiocarcinoma, 27 received neoadjuvant chemoradiotherapy and 22 did not. Overall 1-, 3-, and 5-year post-transplantation survival rates were 65 per cent, 51 per cent and 41 per cent respectively in the group receiving neoadjuvant chemoradiotherapy and 91 per cent, 68 per cent and 53 per cent respectively in the group not receiving neoadjuvant chemoradiotherapy (1-year hazards ratio (HR) 4.55 (95 per cent c.i. 0.98 to 21.13), P = 0.053; 3-year HR 2.07 (95 per cent c.i. 0.78 to 5.54), P = 0.146; 5-year HR 1.71 (95 per cent c.i. 0.71 to 4.09), P = 0.229). Hepatic vascular complications were more frequent in the group receiving neoadjuvant chemoradiotherapy compared with the group not receiving neoadjuvant chemoradiotherapy (nine of 27 versus two of 22, P = 0.045). In multivariable analysis, tumour recurrence occurred less frequently in the group receiving neoadjuvant chemoradiotherapy (HR 0.30 (95 per cent c.i. 0.09 to 0.97), P = 0.044). CONCLUSION: In selected patients undergoing liver transplantation for perihilar cholangiocarcinoma, neoadjuvant chemoradiotherapy resulted in a lower risk of tumour recurrence, but was associated with a higher rate of early hepatic vascular complications. Adjustments in neoadjuvant chemoradiotherapy reducing the risk of hepatic vascular complications, such as omitting radiotherapy, may further improve the outcome in patients undergoing liver transplantation for perihilar cholangiocarcinoma.

Liver transplantation and hepatocellular carcinoma: is TIPS deleterious? A multicentric retrospective study of the ARCHET research group with propensity score matching.

PURPOSE: A transjugular intrahepatic portosystemic shunt (TIPS) before the liver transplantation (LT) has been considered a contraindication in cases of hepatocellular carcinoma (HCC) because of the risk of tumour growth. We aimed to assess the impact of TIPS on incidental HCC and oncological outcomes in transplanted patients with pre-existing HCC. METHODS: All consecutive transplanted patients for cirrhosis who had a previous TIPS with or without HCC were included. Between 2007 and 2014, 1912 patients were transplanted. We included 122 (6.3%) patients having TIPS before LT. A 1:3 matched cohort of 366 patients (18.9%) having LT without previous TIPS was selected using a propensity score. Incidental HCC rate and risk factor of HCC recurrence were evaluated using multivariate analysis with a competing risk model. RESULTS: Before LT, in the TIPS group, 27 (22.1%) had an HCC vs. 81 (22.1%) in the control group (p = 1). The incidental HCC rate was similar: 10.5% (10/95) in the TIPS group vs. 6.3% (18/285) in the control group (p = 0.17). Recurrence occurred in 1/27 (3.7%) patient in the TIPS group and in 7/81 (8.6%) patients in the control group, without significant difference (p = 0.51). After multivariate regression, patient's gender (p < 0.01) was significantly associated with HCC recurrence while a tumour within Milan criteria (p = 0.01, sHR: 0.17 [0.04; 0.7]) and an incidental HCC (p<0.01) were found to be protector factors against HCC recurrence. CONCLUSION: TIPS did not worsen the prognosis of transplanted patients for HCC. TIPS should no longer be contraindicated for oncological reasons in patients with HCC waiting for an LT.

Comparison of reconstruction methods used during liver transplantation in case of a graft with replaced or accessory right hepatic artery: A retrospective study.

Variations in graft arterial anatomy can increase the risk of postoperative hepatic arterial thrombosis (HAT), especially in presence of a replaced or accessory right hepatic artery (RHA). We retrospectively analyzed 223 cases of liver transplantations with the presence of an RHA on the graft. Patient outcomes were compared according to the four different reconstruction methods used: (i) the re-implantation of the RHA into the splenic or gastroduodenal artery (n = 106); (ii) the interposition of the superior mesenteric artery (SMA) (n = 83); (iii) dual anastomosis (n = 24); (iv) use of an aortic patch including the origins of both the SMA and the coeliac trunk (n = 10). A competing risk analysis and Inverse Probability Weighting (IPW) were used. We found that the interposition of the SMA method was associated with a significantly lower incidence of HAT, at 4.8% compared to the re-implantation method at 17.9%, dual anastomosis at 12.5%, and aortic patch at 20%, p = .03. In the competing risk analysis with IPW, the only risk factor for RHA thrombosis was the type of reconstruction. Taking the SMA interposition group as the reference, the sub-hazard ratio (sHR) was 5.05 (CI 95 [1.72; 14.78], p < .01) for the re-implantation group, sHR = 2.37 (CI 95 [0.51; 11.09], p = .27) for the dual anastomosis group and sHR = 2.24 (CI 95 [0.35; 14.33], p = .40) for the aortic patch group. There were no differences for intraoperative transfusion, hospitalization duration (p = .37) or incidence of severe complications (p = .1). The long-term graft (p = .69) and patient (p = .52) survival was not different. In conclusion, the SMA interposition method was associated with a lower incidence of RHA thrombosis.

Waitlist mortality of young patients with biliary atresia: Impact of allocation policy and living donor liver transplantation.

Patients with biliary atresia (BA) below 2 years of age in need of a transplantation largely rely on partial grafts from deceased donors (deceased donor liver transplantation [DDLT]) or living donors (living donor liver transplantation [LDLT]). Because of high waitlist mortality in especially young patients with BA, the Eurotransplant Liver Intestine Advisory Committee (ELIAC) has further prioritized patients with BA listed before their second birthday for allocation of a deceased donor liver since 2014. We evaluated whether this Eurotransplant (ET) allocation prioritization changed the waitlist mortality of young patients with BA. We used a pre-post cohort study design with the implementation of the new allocation rule between the two periods. Participants were patients with BA younger than 2 years who were listed for liver transplantation in the ET database between 2001 and 2018. Competing risk analyses were performed to assess waitlist mortality in the first 2 years after listing. We analyzed a total of 1055 patients with BA, of which 882 had been listed in the preimplementation phase (PRE) and 173 in the postimplementation phase (POST). Waitlist mortality decreased from 6.7% in PRE to 2.3% in POST ( p = 0.03). Interestingly, the proportion of young patients with BA undergoing DDLT decreased from 32% to 18% after ET allocation prioritization ( p = 0.001), whereas LDLT increased from 55% to 74% ( p = 0.001). The proportional increase in LDLT decreased the median waitlist duration of transplanted patients from 1.5 months in PRE to 0.85 months in POST ( p = 0.003). Since 2014, waitlist mortality in young patients with BA has strongly decreased in the ET region. Rather than associated with prioritized allocation of deceased donor organs, the decreased waitlist mortality was related to a higher proportion of patients undergoing LDLT.

Drug transporters are implicated in the diffusion of tacrolimus into the T lymphocyte in kidney and liver transplant recipients: Genetic, mRNA, protein expression, and functionality.

Because of a narrow therapeutic index and a wide inter- and intra-patient variability, therapeutic drug monitoring of the immunosuppressant drug tacrolimus (TAC) based on whole-blood concentrations (Cblood) is mandatory in solid organ transplant recipients. Using peripheral blood mononuclear cells concentrations (CPBMC) could improve patient outcomes. The poor correlation between Cblood and CPBMC makes hypothesize that drug transporters are implicated in the intracellular accumulation of TAC. The aim of this work was therefore to clinically study: i) the role of genetic variants and ii) the effect of mRNA and protein expression of 4 drug transporters on the TAC CPBMC/blood ratio. In addition, functional in vitro experiments were performed to mechanistically validate the clinical observations. Genetic variants of ABCB1/P-gp and SLC28A3/CNT3 did not influence TAC CPBMC in liver transplant recipients (LTR). ABCC2/MRP2 at the mRNA level; ABCB1/P-gp, SLC28A3/CNT3 and SLC29A1/ENT1 at the protein level; correlated with the CPBMC/blood in kidney and LTR. In vitro results suing transporter-expressing cells confirmed that TAC is substrate of P-gp but not MRP2, whereas experiments remained inconclusive for CNT3 and ENT1. In conclusion, the genetic-transcription-protein-functional approach presented in this work provides new insights in the understanding of TAC transport at the T lymphocyte plasma membrane.

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.

Prolonged preservation by hypothermic machine perfusion facilitates logistics in liver transplantation: A European observational cohort study.

A short period (1-2 h) of hypothermic oxygenated machine perfusion (HOPE) after static cold storage is safe and reduces ischemia-reperfusion injury-related complications after liver transplantation. Machine perfusion time is occasionally prolonged for logistical reasons, but it is unknown if prolonged HOPE is safe and compromises outcomes. We conducted a multicenter, observational cohort study of patients transplanted with a liver preserved by prolonged (≥4 h) HOPE. Postoperative biochemistry, complications, and survival were evaluated. The cohort included 93 recipients from 12 European transplant centers between 2014-2021. The most common reason to prolong HOPE was the lack of an available operating room to start the transplant procedure. Grafts underwent HOPE for a median (range) of 4:42 h (4:00-8:35 h) with a total preservation time of 10:50 h (5:50-20:50 h). Postoperative peak ALT was 675 IU/L (interquartile range 419-1378 IU/L). The incidence of postoperative complications was low, and 1-year graft and patient survival were 94% and 88%, respectively. To conclude, good outcomes are achieved after transplantation of donor livers preserved with prolonged (median 4:42 h) HOPE, leading to a total preservation time of almost 21 h. These results suggest that simple, end-ischemic HOPE may be utilized for safe extension of the preservation time to ease transplantation logistics.

Prolonged dual hypothermic oxygenated machine preservation (DHOPE-PRO) in liver transplantation: study protocol for a stage 2, prospective, dual-arm, safety and feasibility clinical trial.

INTRODUCTION: End-ischaemic preservation of a donor liver by dual hypothermic oxygenated machine perfusion (DHOPE) for 2 hours prior to transplantation is sufficient to mitigate ischaemia-reperfusion damage and fully restore cellular energy levels. Clinical studies have shown beneficial outcomes after transplantation of liver grafts preserved by DHOPE compared with static cold storage. In addition to graft reconditioning, DHOPE may also be used to prolong preservation time, which could facilitate logistics for allocation and transplantation globally. METHODS AND ANALYSIS: This is a prospective, pseudo-randomised, dual-arm, IDEAL-D (Idea, Development, Exploration, Assessment, Long term study-Framework for Devices) stage 2 clinical device trial designed to determine safety and feasibility of prolonged DHOPE (DHOPE-PRO). The end-time of the donor hepatectomy will determine whether the graft will be assigned to the intervention (16:00-3:59 hour) or to the control arm (4:00-15:59 hour). In total, 36 livers will be included in the study. Livers in the intervention group (n=18) will undergo DHOPE-PRO (≥4 hours) until implantation the following morning, whereas livers in the control group (n=18) will undergo regular DHOPE (2 hours) prior to implantation. The primary endpoint of this study is a composite of the occurrence of all (serious) adverse events during DHOPE and up to 30 days after liver transplantation. ETHICS AND DISSEMINATION: The protocol was approved by the Medical Ethical Committee of Groningen, METc2020.126 in June 2020, and the study was registered in the Netherlands National Trial Registry (https://www.trialregister.nl/) prior to initiation. TRIAL REGISTRATION NUMBER: NL8740.

Renoportal Anastomosis During Liver Transplantation in Patients With Portal Vein Thrombosis: First Long-term Results From a Multicenter Study.

OBJECTIVE: To evaluate the short- and long-term outcomes of RPA in a large multicentric series. SUMMARY BACKGROUND: The current knowledge on RPA for portal reconstruction during LT in patients with diffuse PVT and a large splenorenal shunt is poor and limited to case reports and small case series. METHODS: All consecutive LTs with RPA performed in 5 centers between 1998 and 2020 were included. RPA was physiological provided it drained the splanchnic venous return through a large splenorenal shunt (≥ 1 cm diameter). Complications of PHT, long-term RPA patency, and patient and graft survival were assessed. RPA success was achieved provided the 3 following criteria were all fulfilled: patients were alive with patent RPA and without clinical PHT. RESULTS: RPA was attempted and feasible in 57 consecutive patients and was physiological in 51 patients (89.5%). Ninety-day mortality occurred in 5 (8.5%) patients, and PHT-related complications occurred in 42.9% of patients. With a median follow-up of 63 months, the 1-, 3- and 5-year patient and graft survival rates were 87%, 83%, and 76% and 82%, 80%, and 73%, respectively. The primary and primary-assisted patency rates at 5 years were 84.5% and 94.3%, respectively. Success was achieved in 90% (27/30) of patients with a follow-up ≥5 years. CONCLUSIONS: Despite a high rate of PHT-related complications, excellent long-term patient and graft survival could be achieved. RPA could be considered successful in the vast majority of patients. The expanded use of RPA is warranted.

Influence of the ABO Blood Group System on Hepatocellular Carcinoma Recurrence After Liver Transplantation.

BACKGROUND: The ABO blood group system may influence tumorigenesis, but its prognostic value in liver transplantation (LT) for hepatocellular carcinoma (HCC) has never been assessed. METHODS: All consecutive patients who underwent LT for HCC between 2013 and 2017 at 9 centers were analyzed. Predictors of tumor recurrence were identified using multivariable analysis, while comparison between group A and non-A recipients was performed after propensity score matching. RESULTS: Among 925 LT recipients, 406 were blood group A, 94 group B, 380 group O, and 45 group AB. On multivariable analysis, group A was associated with tumor recurrence (hazard ratio [HR] = 1.574 [95% confidence interval; 95% CI = 1.034-2.394] P = 0.034). After propensity score matching, 1- and 5-y recurrence rates were 7.4% and 20.1% in group A recipients versus 3.3% and 13.2% in non-A recipients (HR = 1.66 [95% CI = 1.12-2.45], P = 0.011). One and 5-y recurrence-free survivals were 85.2% and 66.8% in group A recipients versus 88.5% and 71.3% in non-A recipients (HR = 1.38 [95% CI = 1.01-1.90], P = 0.045). Among recipients within Milan criteria (n = 604), 1- and 5-y recurrence rates were 5.8% and 12.7% in group A recipients versus 3.1% and 12.2% in non-A recipients (HR = 1.197 [95% CI = 0.721-1.987], P = 0.485). Among recipients outside Milan criteria (n = 182), 1- and 5-y recurrence rates were 12.1% and 43.8% in group A recipients versus 3.9% and 15.6% in non-A recipients (HR = 3.175 [95% CI = 1.526-6.608], P = 0.002). CONCLUSIONS: ABO blood system influences the oncological outcome of recipients undergoing LT for HCC. Its incorporation in the prognostication model of LT for HCC may allow improving the management of LT candidates.

Oxygenated versus non-oxygenated flush out and storage of donor livers: An experimental study.

BACKGROUND: During donor organ procurement and subsequent static cold storage (SCS), hepatic adenosine triphosphate (ATP) levels are progressively depleted, which contributes to ischemia-reperfusion injury (IRI). We sought to investigate a simple approach to prevent ATP depletion and IRI using a porcine donation after circulatory death (DCD) liver reperfusion model. METHODS: After 30 min warm ischemia, porcine livers were flushed via the portal vein with cold (4°C) non-oxygenated University of Wisconsin (UW) preservation solution (n = 6, control group) or with oxygenated UW (n = 6, OxyFlush group). Livers were then subjected to 4 h SCS in non-oxygenated (control) or oxygenated (OxyFlush) UW, followed by 4 h normothermic reperfusion using whole blood. Hepatic ATP levels were compared, and hepatobiliary function and injury were assessed. RESULTS: At the end of SCS, ATP was higher in the OxyFlush group compared to controls (delta ATP of +0.26 vs. -0.68 µmol/g protein, p = 0.04). All livers produced bile and metabolized lactate, and there were no differences between the groups. Grafts in the OxyFlush group had lower blood glucose levels after reperfusion (p = 0.04). Biliary pH, glucose and bicarbonate were not different between the groups. Injury markers including liver transaminases, lactate dehydrogenase, malondialdehyde, cell-free DNA and flavin mononucleotide in the SCS solution and during reperfusion were also similar. Histological assessment of the parenchyma and bile ducts did not reveal differences between the groups. CONCLUSION: Oxygenated flush out and storage of DCD porcine livers prevents ATP depletion during ischemia, but this does not seem sufficient to mitigate early signs of IRI.

Therapeutic anticoagulation after liver transplantation is not useful among patients with pre-transplant Yerdel-grade I/II portal vein thrombosis: A two-center retrospective study.

BACKGROUND: Portal vein thrombosis (PVT) is no longer a contraindication for liver transplantation (LT). While therapeutic anticoagulation (tAC) is recommended during the waiting period, there is no evidence for its usefulness in the prevention of PVT recurrence after LT. OBJECTIVES: The aim of our study was to evaluate the role of tAC post-LT in the prevention of PVT recurrence. PATIENTS/METHODS: All adult LTs performed in two high-volume centers between 2003 and 2018 were retrospectively analysed. Only patients with PVT classified as Yerdel grade I or II and with standard portal reconstruction were included. PVT recurrence and tAC-associated morbidity within 1 year were compared between patients receiving tAC or not. RESULTS: During the study period, of 2612 LTs performed, 235 (9%) patients with PVT were included; 113 patients (48.1%) received post-LT tAC (tAC group) while 122 (51.9%) did not (non-tAC group). The incidence of bleeding events was significantly higher in the tAC group (26 [23%] vs. 5 [4.1%], P < .01) and the initial hospitalization duration was longer (21 vs. 17.5 days, P < .01). Within the first year, PVT recurrence was observed for 9 (3.8%) patients without any difference between the tAC and non-tAC groups (6 [5.1%] vs. 3 [2.5%], P = .39). The only identified risk factor for PVT recurrence was the recipients' age (odds ratio= 0.94, P = .03). Graft (P = .11) and patient (P = .44) survival were similar between the two groups. CONCLUSION: Therapeutic anticoagulation is not necessary in the prevention of grade I/II PVT recurrence and is associated with higher morbidity and longer hospital stay.