Comparative analysis of the results of orthotopic liver transplantation in patients with and without portal vein thrombosis

Left Gastric Vein Direct Anastomosis as Alternative to Portal Flow Reconstruction in Liver Transplantation

Introduction

The most relevant limiting factor for performing end-to-end anastomosis is portal vein thrombosis (PVT), which leads to challenging vascular reconstructions. This study aimed to analyze a single center's experience using the left gastric vein (LGV) for portal flow reconstruction in liver transplantation (LT).

Methods

This retrospective observational study reviewed laboratory and imaging tests, a description of the surgical technique, and outpatient follow-up of patients with portal system thrombosis undergoing LT with portal flow reconstruction using the LGV. This study was conducted at a single transplant reference center in the northeast region of Brazil from January 2016 to December 2021.

Results

Between January 2016 and December 2021, 848 transplants were performed at our center. Eighty-two patients (9.7%) presented with PVT, most of whom were treated with thrombectomy. Nine patients (1.1% with PVT) had extensive thrombosis of the portal system (Yerdel III or IV), which required end-to-side anastomosis between the portal vein and the LGV without graft, and had no intraoperative complications. All patients had successful portal flow in Doppler ultrasound control evaluations.

Discussion

The goal was to reestablish physiological flow to the graft. A surgical strategy includes using the LGV graft. According to our reports, using LGV fulfilled the requirements for excellent vascular anastomosis and even allowed the dispensing of venous grafts. This is the largest case series in a single center of reconstruction of portal flow with direct anastomosis with the LGV without needing a vascular graft.

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.

Portal vein surgical treatment on non-tumoral portal vein thrombosis in liver transplantation: Systematic Review and Meta-Analysis

Non-tumoral portal vein thrombosis (PVT) is associated with higher morbidity and mortality in liver transplantation (LT). In this study, we aimed to evaluate the impact of PVT in LT outcomes and analyze the types of surgical techniques used for dealing with PVT during LT. A systematic review was conducted in Cochrane, MEDLINE, and EMBASE databases, selecting articles from January 1990 to December 2019. The MESH-terms used were ("Portal Vein"[Mesh] AND "Thrombosis"[Mesh] NOT "Neoplasms"[Mesh]) AND ("Liver Transplantation"[Mesh]). The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) recommendation was used, and meta-analysis was performed with Review Manager Version 5.3 software. A total of 1,638 articles were initially found: 488 in PubMed, 289 in Cochrane Library, and 861 in EMBASE, from which 27 were eventually selected for the meta-analysis. Surgery time of LT in patients with PVT was longer than in patients without LT (p<0.0001). Intraoperative red blood cell (p<0.00001), fresh frozen plasma (p=0.01), and platelets (p=0.03) transfusions during LT were higher in patients with PVT. One-year (odds ratio [OR] 1.17; p=0.002) and 5-year (OR 1.12; p=0.01) patient survival after LT was worse in the PVT group. Total occlusive PVT presented higher mortality (OR 3.70; p=0.00009) and rethrombosis rates (OR 3.47 [1.18-10.21]; p=0.02). PVT Yerdel III/IV classification exhibited worse 1-year [2.04 (1.21-3.42); p=0.007] and 5-year [0.98 (0.59-1.62); p=0.93] patient survival. Thrombectomy with primary anastomosis was associated with better outcomes. LT in patients with non-tumoral PVT demands more surgical time, needs more intraoperative transfusion, and presents worse 1- and 5-year patient survival. Total occlusive PVT and Yerdel III/IV PVT classification were associated with higher mortality. (PROSPERO, registration number: CRD42020132915).

Imaging post liver transplantation part I: vascular complications

Liver transplantation continues to rise in frequency, with over 1,000 procedures performed in the UK in 2018. Complications are increasingly uncommon but when they occur, early recognition and intervention is vital to save grafts. Imaging after the perioperative period is often performed at patients' local hospitals meaning that all radiologists and sonographers need to have an understanding of how to assess a transplant liver. Part I of this series will focus on vascular complications, including the normal postoperative vascular anatomy following liver transplantation, normal post-transplantation vascular imaging findings and abnormal findings that may prompt further investigation. Vascular complications following liver transplantation will be illustrated using a collection of cases.

Case Report: Portal Vein Thrombosis, Surgical Alternatives in Liver Transplantation

INTRODUCTION

Liver transplant remains a surgical challenge in cases of portal vein thrombosis. Ten percent of patients listed for liver transplant have this diagnosis preoperatively. Although several techniques of portal revascularization are available, sometimes the best result is not achieved, depending on the extent of thrombosis.

OBJECTIVE

The aim of this article is to report our experience in 2 particular cases of liver transplant with portal vein thrombosis.

MATERIAL AND METHODS

We present the cases of 2 patients with partial portal thrombosis that extended to the porto-spleno-mesenteric system. The first case is a 36-year-old woman with recurrence of autoimmune liver disease requiring a second graft; the second case concerns a 64-year-old man with alcoholic liver cirrhosis.

RESULTS

Both patients had a splenorenal shunt. A portal bypass with a Y venous graft was performed using the cavoiliac veins of the donor. The anastomosis was performed to the superior mesenteric and left renal veins.

DISCUSSION AND CONCLUSIONS

These clinical cases demonstrate that portal vein thrombosis is not an absolute contraindication for transplantation and that surgical alternatives exist in cases of grade III portal vein thrombosis.

Liver Transplantation

The field of liver transplantation has changed since the MELD scoring system became the most widely used donor allocation tool. Due to the MELD-based allocation system, sicker patients with higher MELD scores are being transplanted. Persistent organ donor shortages remain a challenging issue, and as a result, the wait-list mortality is a persistent problem for most of the regions. This chapter focuses on deceased donor and live donor liver transplantation in patients with complications of portal hypertension. Special attention will also be placed on donor-recipient matching, perioperative management of transplant patients, and the impact of hepatic hemodynamics on transplantation.

Novel classification of non-malignant portal vein thrombosis: A guide to surgical decision-making during liver transplantation

Non-tumoral portal vein thrombosis (PVT) is present at liver transplantation in 5% to 26% of cirrhotic patients, and the prevalence of complex PVT as defined here (grade 4 Yerdel, and grade 3,4 Jamieson and Charco) has been reported in 0% to 2.2%. Adequate portal inflow is mandatory to ensure graft and patient survival after liver transplantation. With time, the proposed classifications of non-tumoral chronic PVT have evolved from being anatomy-based, to also incorporating functional parameters. However, none of the currently proposed classifications are directed towards decision-making, regarding the choice of inflow to the graft during transplantation and the outcomes thereof. The present scoping review i) addresses the limits of the currently available classifications in terms of surgical decisiveness, ii) clarifies the concept of physiological or non-physiological portal inflow reconstruction, and subsequently, iii) proposes a new classification of non-tumoral PVT in candidates for liver transplantation; to help tailor the surgical strategy to an individual patient, in order to provide portal inflow to the graft together with control of prehepatic portal hypertension whenever feasible.

Outcome of Liver Transplant Patients With Intraoperative-Detected Portal Vein Thrombosis: A Retrospective Cohort Study in Shiraz, Iran

OBJECTIVES

We aimed to determine outcomes and predictors of intraoperative-detected portal vein thrombosis in liver transplant recipients.

MATERIALS AND METHODS

We retrospectively analyzed 806 adult liver transplant recipients from Shiraz, Iran, to determine those with intraoperative-detected portal vein thrombosis. Patients with this complication were compared with age- and sex-matched patients without this complication. Background diseases, surgery parameters, hospital admission, reoperation, rethrombosis, acute rejection, and use of antico-agulants were assessed. Cox proportional hazards, logistic regression, and random classification forest and random survival forest plots were used for data analyses.

RESULTS

Mean age of patients was 44.7 ± 13.2 years. Patients with intraoperative-detected portal vein thrombosis (n = 91; 11.3%) had mortality ratio of 2.9 (range, 1.0-8.6) and 2-year survival of 78% versus 2-year survival rate of 92% in patients without this disease. Median time of survival in patients with this complication who died was 2 weeks versus 10 months in patients who died and did not have this complication. Random classification forest plots showed that high fasting blood sugar, autoimmune hepatitis, low prothrombin time, and cryptogenic cirrhosis were (in order) the main predictors of this complication. Random survival forest plots revealed that low prothrombin time, having intraoperative-detected portal vein thrombosis, Model for End Stage Liver Disease score, primary sclerosing cholangitis, diabetes mellitus, and hepatocellular carcinoma were (in order) the main predictors of death in liver transplant recipients. Low body mass index was associated with mortality in patients with intraoperative-detected portal vein thrombosis (by Cox proportional hazards).

CONCLUSIONS

One of every 9 liver transplant patients had intraoperative-detected portal vein thrombosis. Hazard of death was 2.9, and death occurred far earlier in patients with this complication. Improvements in diabetes mellitus care, prothrombin time, Model for End-Stage Liver Disease score, and body mass index may improve outcomes of these patients.

[Portal perfusion with right gastroepiploic vein flow in liver transplant]

BACKGROUND

Liver transplantation in patients with liver cirrhosis, portal vein thrombosis, and cavernous transformation of the portal vein, is a complex procedure with high possibility of liver graft dysfunction. It is performed in 2-19% of all liver transplants, and has a significantly high mortality rate in the post-operative period. Other procedures to maintain portal perfusion have been described, however there are no reports of liver graft perfusion using right gastroepiploic vein.

CLINICAL CASE

A 20 year-old female diagnosed with cryptogenic cirrhosis, with a Child-Pugh score of 7 points (class "B"), and MELD score of 14 points, with thrombosis and cavernous transformation of the portal vein, severe portal hypertension, splenomegaly, a history of upper gastrointestinal bleeding due to oesophageal varices, and left renal agenesis. The preoperative evaluation for liver transplantation was completed, and the right gastroepiploic vein of 1-cm diameter was observed draining to the infrahepatic inferior vena cava and right suprarenal vein. An orthotopic liver transplantation was performed from a non-living donor (deceased on January 30, 2005) using the Piggy-Back technique. Portal vein perfusion was maintained using the right gastroepiploic vein, and the outcome was satisfactory. The patient was discharged 13 days after surgery.

CONCLUSIONS

Liver transplantation was performed satisfactorily, obtaining an acceptable outcome. In this case, the portal perfusion had adequate blood flow through the right gastroepiploic vein.

Perioperative thrombotic complications in liver transplantation

Although the perioperative bleeding complications and the major side effects of blood transfusion have always been the primary concern in liver transplantation (OLT), the possible cohesion of an underestimated intrinsic hypercoagulative state during and after the transplant procedure may pose a major threat to both patient and graft survival. Thromboembolism during OLT is characterized not only by a complex aetiology, but also by unpredictable onset and evolution of the disease. The initiation of a procoagulant process may be triggered by various factors, such as inflammation, venous stasis, ischemia-reperfusion injury, vascular clamping, anatomical and technical abnormalities, genetic factors, deficiency of profibrinolytic activity, and platelet activation. The involvement of the arterial system, intracardiac thrombosis, pulmonary emboli, portal vein thrombosis, and deep vein thrombosis, are among the most serious thrombotic events in the perioperative period. The rapid detection of occlusive vascular events is of paramount importance as it heavily influences the prognosis, particularly when these events occur intraoperatively or early after OLT. Regardless of the lack of studies and guidelines on anticoagulant prophylaxis in this setting, many institutions recommend such an approach especially in the subset of patients at high risk. However, the decision of when, how and in what doses to use the various chemical anticoagulants is still a difficult task, since there is no common consensus, even for high-risk cases. The risk of postoperative thromboembolism causing severe hemodynamic events, or even loss of graft function, must be weighed and compared with the risk of an important bleeding. In this article we briefly review the risk factors and the possible predictors of major thrombotic complications occurring in the perioperative period, as well as their incidence and clinical features. Moreover, the indications to pharmacological prophylaxis and the current treatment strategies are also summarized.

Safety and effectiveness of renoportal bypass in patients with complete portal vein thrombosis: an analysis of 10 patients

The presence of portal vein thrombosis (PVT) is still considered by many transplantation centers to be an absolute contraindication to liver transplantation because of the technical difficulties that it can present and its association with a higher rate of patient morbidity and mortality. Renoportal bypass (RPB) can help to remove these barriers. This study describes our institution's experience with RPB through the description of a new and successful simplified surgical strategy, a patient and graft outcome analysis, intraoperative vascular flow measurements, and the use of splenic artery embolization (SAE) as an effective adjunct for treating sporadic cases of unrelieved portal hypertension. Between January 2004 and January 2013, 10 patients with grade 4 PVT underwent RPB. At the last follow-up (42.2 ± 21.1 months), the patient and graft survival rates were 100%. Five patients (50%) experienced posttransplant ascites, and 2 of those underwent proximal SAE to modulate the liver inflow and overcome the ascites. Three patients (30%) experienced transient kidney injury in the early posttransplant period and were treated efficiently with medical therapy. The renoportal flows were close to the desirable 100 mL/100 g of liver tissue in all cases. The experience and data support RPB as a feasible and easily reproducible technique without the risks and technical challenges associated with the tedious dissection of a cavernous hilum.

Portal vein thrombosis in cirrhosis

Portal vein thrombosis (PVT) is being increasingly recognized in patients with advanced cirrhosis and in those undergoing liver transplantation. Reduced flow in the portal vein is probably responsible for clotting in the spleno-porto-mesenteric venous system. There is also increasing evidence that hypercoagulability occurs in advanced liver disease and contributes to the risk of PVT. Ultrasound based studies have reported a prevalence of PVT in 10-25% of cirrhotic patients without hepatocellular carcinoma. Partial thrombosis of the portal vein is more common and may not have pathophysiological consequences. However, there is high risk of progression of partial PVT to complete PVT that may cause exacerbation of portal hypertension and progression of liver insufficiency. It is thus, essential to accurately diagnose and stage PVT in patients waiting for transplantation and consider anticoagulation therapy. Therapy with low molecular weight heparin and vitamin K antagonists has been shown to achieve complete and partial recanalization in 33-45% and 15-35% of cases respectively. There are however, no guidelines to help determine the dose and therapeutic efficacy of anticoagulation in patients with cirrhosis. Anticoagulation therapy related bleeding is the most feared complication but it appears that the risk of variceal bleeding is more likely to be dependent on portal pressure rather than solely related to coagulation status. TIPS has also been reported to restore patency of the portal vein. Patients with complete PVT currently do not form an absolute contraindication for liver transplantation. Thrombectomy or thromboendovenectomy is possible in more than 75% of patients followed by anatomical end-to-end portal anastomosis. When patency of the portal vein and/or superior mesenteric vein is not achieved, only non-anatomical techniques (reno-portal anastomosis or cavo-portal hemitransposition) can be performed. These techniques, which do not fully reverse portal hypertension, are associated with higher morbidity and mortality risks in the short term.

Portal vein thrombosis and liver transplantation: implications for waiting list period, surgical approach, early and late follow-up

Portal vein thrombosis (PVT) is a well-known and relatively common complication of liver cirrhosis. In the past, PVT was considered as a contraindication for liver transplantation (LT). To characterize prevalence, risk factors, perioperative management and outcome of PVT in the setting of LT, the English literature published between 1991 and 2011 was reviewed. Of 6807 articles, 280 were selected, and 39 experiences were analyzed in detail (methodology, type and duration of treatments, peri-operative management, strategy to avoid recurrence, strengths and weaknesses, Oxford evidence level, citations). 3/39 studies were prospective; 9/39 were based on prospectively recorded databases; no studies of 1, 2a, 3a level of evidence were present; 5/39 were recognized as level 2b, 23/39 as level 3b, and 8/39 as level 4. High complication rate has been reported with consequent effect on graft and patient survival. Overall, PVT presents today good results similar to those obtained in patients without PVT undergoing LT even if they require a higher transfusion number and a longer ICU/hospital stay. Reported cases were retrospectively stratified according to Yerdel classification. Grade 1-2 patients (76%) do well with eversion thromboendovenectomy, resection of damaged vein and porto-portal anastomosis. Results of patients with grade 3-4 (24%) are inferior, however data on outcome in this subsets are fragmented and do not allow a reliable analysis. Moreover, results obtained in grade 3-4 cases are better in transplant centers with large specific experience. The small number of reports suggests caution. The role of anticoagulant treatment is still debated. Although in cirrhotics with PVT LT remains a demanding procedure, PVT should not be considered a contraindication anymore.

Renal relevant radiology: imaging in kidney transplantation

Kidney transplantation can be associated with various complications that vary from vascular complications to urologic disorders to immunologic adverse effects. In evaluating the recipient with graft dysfunction, clinicians can choose among several imaging modalities, including ultrasonography, nuclear medicine studies, computed tomography, and magnetic resonance imaging. This review discusses the evaluation of the kidney transplant recipient using these imaging procedures, emphasizing the clinical diagnostic utility and role of each modality. A kidney biopsy is often required as a gold standard for diagnostic purposes. However, because of the inherent risks of a kidney biopsy, noninvasive imaging in diagnosing causes of graft dysfunction is a highly desired tool used and needed by the transplant community. Because the diagnostic accuracy varies depending on the time course and nature of the transplant-related complication, this review also addresses the advantages and limitations of each modality. The recent advances in kidney transplant imaging techniques and their clinical implications are also discussed.

Multiple ways to manage portal thrombosis during liver transplantation: surgical techniques and outcomes

BACKGROUND

Portal vein thrombosis (PVT) is a well-recognized complication of chronic liver disease with a prevalence ranging from 1% to 16%.

MATERIALS AND METHODS

We performed a retrospective review of 447 consecutive patients who underwent liver transplantation (OLT) between October 2000 and December 2011 comparing 51 recipients with PVT (study group) with 399 without PVT (control group). The aim of this study was to determine the impact of pre-existent PVT on the surgical procedure, to identify specific preventable perioperative complications, and based on our studies and other works, to determine whether this group of patients are acceptable candidates for OLT.

RESULTS

Among the 51 patients with PVT, 44 showed partial and 7 complete thrombosis. In 47 cases, we performed a thromboendovenectomy. There were six anastomoses at the confluence of the superior mesenteric vein (SMV) and one, with a venous graft interposition. In four complete thrombosis recipients we performed an extra-anatomic by pass between the main trunk of the SMV and the donor portal vein. Compared with the control group, regarding preoperative characteristics, PVT patients were older at the time of transplantation (P = .001) and had a higher use of TIPS (P = .02). The operative characteristics showed a longer warm ischemia time in the PVT group (46.9 ± 22.5 vs 39.3 ± 15 min; P = .004). There were significant differences in postoperative evaluations, nor in the complication rates. Overall survivals at 10 years were similar: 61.7% versus 65.3%; (P = .9).

CONCLUSION

Although PVT was associated with greater operative complexity, it had no influence on postoperative complications or overall survival.

Management of nonneoplastic portal vein thrombosis in the setting of liver transplantation: a systematic review

BACKGROUND

Nonneoplastic portal vein thrombosis (PVT) is frequent in patients with cirrhosis who undergo liver transplantation (LT); however, data on its impact on outcome and strategies of management are sparse.

METHODS

A systematic review of the literature was performed by analyzing studies that report on PVT in LT recipients and were published between January 1986 and January 2012.

RESULTS

Of 25,753 liver transplants, 2004 were performed in patients with PVT (7.78%), and approximately half presented complete thrombosis. Thrombectomy/thromboendovenectomy was employed in 75% of patients; other techniques included venous graft interposition and portocaval hemitransposition. Overall, the presence of PVT significantly increased 30-day (10.5%) and 1-year (18.8%) post-LT mortality when compared to patients without PVT (7.7% and 15.4%, respectively). However, only complete PVT accounted for this increased mortality. Rethrombosis occurred in up to 13% of patients with complete PVT and in whom no preventative strategies were used, and was associated with increased morbidity and mortality.

CONCLUSIONS

PVT is common in patients with cirrhosis undergoing LT, and it affects survival when it is complete, at least in the short term after transplant. Therefore, screening for this condition is essential, alongside adequate treatment strategies to attempt repermeation of the PV and prevent thrombosis extension.

Anticoagulation for the treatment of thrombotic complications in patients with cirrhosis

Cirrhotic patients can develop thrombotic complications, which in this group of patients occur with a greater frequency than in the general population. Portal vein thrombosis (PVT) is the most common thrombotic phenomenon, although deep venous thrombosis and pulmonary embolism can also occur. Risk factors for thrombosis include inherited and acquired deficiency of factors involved in anticoagulation mechanisms, venous stasis of the portal vein owing to architectural derangement of the liver and possibly local factors related to the endothelium. Clinical manifestations of PVT range from asymptomatic disease to a life-threatening complication, and although it is no longer considered an absolute contraindication for liver transplant, its presence may require challenging surgical techniques, which entail greater morbidity. Anticoagulation therapy is henceforth an important strategy to treat cirrhotic patients with PVT, although experience in this group of patients is limited. Vitamin K antagonists and low-molecular-weight heparin have been used successfully, achieving recanalization of the thrombosed vessel in patients with cirrhosis; however, the precise drug regimen management and monitoring has not be fully explored in this group of patients.

Obesity is an independent risk factor for pre-transplant portal vein thrombosis in liver recipients

Background

Portal vein thrombosis is a frequent complication in end-stage cirrhosis with a considerable peri-operative risk for liver transplant candidates. We aimed to characterize the pre-transplant portal vein thrombosis in a cohort of liver transplant recipients, and to identify independent risk factors for this complication.

Methods

380 consecutive primary orthotopic liver transplants were performed in the Digestive Surgery Department of “12 de Octubre” Hospital (Madrid, Spain), between January 2001 and December 2006. The main risk factors considered were smoking, obesity, metabolic disorders, previous immobility, surgery or trauma, nephrotic syndrome, associated tumor, inflammatory disease, neoplasm myeloprolipherative. Furthermore we have reported genetic thrombophilia results for 271 recipients.

Results

Sixty-two (16.3%) patients developed pre-transplant portal vein thrombosis and its presence had no impact in the overall survival of liver recipients. Obesity was the only independent risk factor for pre-transplant portal vein thrombosis.

Conclusion

We recommend close control of cardiovascular factors in patients with liver cirrhosis in order to avoid associated thrombosis.

Efficacy and safety of anticoagulation on patients with cirrhosis and portal vein thrombosis

BACKGROUND & AIMS

Portal vein thrombosis (PVT) is a frequent event in patients with cirrhosis; it can be treated with anticoagulants, but there are limited data regarding safety and efficacy of this approach. We evaluated this therapy in a large series of patients with cirrhosis and non-neoplastic PVT.

METHODS

We analyzed data from 55 patients with cirrhosis and PVT, diagnosed from June 2003 to September 2010, who received anticoagulant therapy for acute or subacute thrombosis (n = 31) or progression of previously known PVT (n = 24). Patients with cavernomatous transformation were excluded. Thrombosis was diagnosed, and recanalization was evaluated by using Doppler ultrasound, angio-computed tomography, and/or angio-magnetic resonance imaging analyses.

RESULTS

Partial or complete recanalization was achieved in 33 patients (60%; complete in 25). Early initiation of anticoagulation was the only factor significantly associated with recanalization. Rethrombosis after complete recanalization occurred in 38.5% of patients after anticoagulation therapy was stopped. Despite similar baseline characteristics, patients who achieved recanalization developed less frequent liver-related events (portal hypertension-related bleeding, ascites, or hepatic encephalopathy) during the follow-up period, but this difference was not statistically significant (P = .1). Five patients developed bleeding complications that were probably related to anticoagulation. A platelet count <50 × 109/L was the only factor significantly associated with higher risk for experiencing a bleeding complication. There were no deaths related to anticoagulation therapy.

CONCLUSIONS

Anticoagulation is a relatively safe treatment that leads to partial or complete recanalization of the portal venous axis in 60% of patients with cirrhosis and PVT; it should be maintained indefinitely to prevent rethrombosis.

Hypercoagulability in cirrhosis: causes and consequences

Decreased levels of most coagulation factors and thrombocytopenia are the main haemostatic abnormalities of cirrhosis. As a consequence, this condition was, until recently, considered as the prototype acquired coagulopathy responsible for bleeding. However, recent evidence suggests that it should, rather, be regarded as a condition associated with normal or even increased thrombin generation. The bleeding events that occur in these patients should, therefore, be explained by the superimposed conditions that frequently occur in this setting. Due to elevated levels of factor VIII (procoagulant driver) in combination with decreased protein C (anticoagulant driver), which are typically found in patients with cirrhosis, a procoagulant imbalance, defined as a partial resistance to the in vitro anticoagulant action of thrombomodulin, can be demonstrated. Whether this in vitro hypercoagulability is truly representative of what occurs in vivo remains to be established. However, the hypothesis that it may have clinical consequences is attractive and deserves attention. The possible consequences that we discuss herein include whether (i) cirrhosis is a condition associated with increased risk of venous thromboembolism or portal vein thrombosis; (ii) the hypercoagulability associated with cirrhosis has any other role outside coagulation (i.e. progression of liver fibrosis); and (iii) anticoagulation should be used in cirrhosis. Although apparently provocative, considering anticoagulation as a therapeutic option in patients with cirrhosis is now supported by a rationale of increasing strength. There may be subgroups of patients who benefit from anticoagulation to treat or prevent thrombosis and to slow hepatic fibrosis. Clinical studies are warranted to explore these therapeutic options.

Occlusive portal vein thrombosis as a new marker of decompensated cirrhosis

Natural history of liver cirrhosis is divided into compensated and decompensated stage. Traditionally, the markers of decompensated cirrhosis include ascites, variceal hemorrhage, hepatic encephalopathy and jaundice. The clinical importance of portal vein thrombosis (PVT) is increasingly recognized in patients with liver cirrhosis. The presence of PVT is not only an independent predictor of failure to control active variceal bleeding and prevent variceal rebleeding, but also significantly associated with increased mortality in patients with liver cirrhosis. Besides, it greatly influences the technical success and outcome of endovascular interventional treatment and liver transplantation for liver cirrhosis and its secondary portal hypertension. Thus, we hypothesize that PVT should be regarded as a critical marker of decompensated cirrhosis, whether clinical events such as the development of ascites, encephalopathy, and variceal bleeding occur or not. Our hypothesis adds PVT into the definition of decompensated cirrhosis and reminds clinicians and investigators that PVT plays a vital role in natural history of liver cirrhosis. Further, it is essential to construct a new system of preventing and treating liver cirrhosis in the presence of PVT.

Outcomes of liver transplantation in candidates with portal vein thrombosis

OBJECTIVE

The objective of the present study was to analyze the incidence of portal vein thrombosis (PVT), comparing morbidity and mortality rates among those affected with and those free of this complication. In the PVT group, we also analyzed mortality related to partial (PPVT) and total (TPVT) thrombosis.

METHODS

We undertook a retrospective study of orthotopic liver transplantations from deceased donors in 617 recipients from January 1991 until October 2008. Recipients were classified according to whether they had PVT. In all cases, we considered age, sex, Model for End-stage Liver Disease score, Child-Pugh score, indication for transplantation, type of thrombosis, surgical technique blood product transfusion, and survival rate.

RESULTS

There were 48 patients with PVT (7.78%) among 670 transplantations in 617 recipients in our institution. Concerning the type of thrombosis, 28 (58.3%) were partial and 20 (41.7%) total with complete occlusion of the portal vein lumen.

CONCLUSION

PVT in liver transplant candidates is a rare event (7.8%) that entails greater difficulty in the procedure, expressed as a longer operative time, greater consumption of blood products, and complex surgical techniques. The prognosis for these patients depends on the type of thrombosis: patients with TPVT showed a higher mortality, whereas those with PPVT had survival rates comparable to those of candidates with a permeable portal vein.

Prevention and treatment of rethrombosis after liver transplantation with an implantable pump of the portal vein

Implantable pumps have been used to prevent deep vein thrombosis and other diseases. In this article, we report for the first time the prevention and treatment of rethrombosis of the portal vein in liver transplantation with an implantable pump of the portal vein. Four hundred four orthotopic liver transplantation cases were retrospectively reviewed and divided into 3 groups: portal vein thrombosis (PVT) patients with an implantable pump (n = 28), PVT patients without an implantable pump (n = 20), and patients without preexisting PVT (n = 356). The following parameters for the 3 groups of patients were calculated and compared: (1) preoperative parameters, including baseline data of the donors and recipients and times of graft ischemia; (2) intraoperative and postoperative parameters, including surgery time, red blood cell and plasma transfusion, platelet concentrate transfusion, bleeding and primary graft malfunction, and duration of the hospital and intensive care unit stays; and (3) follow-up information for the patency of the portal vein, rethrombosis rate, stenosis and reoperation (relaparotomy or retransplantation), in-hospital mortality, and actuarial 1-year survival rate. Among the 3 groups of recipients, no significant differences were detected in preoperative and intraoperative parameters. However, compared to PVT patients without an implantable pump, PVT patients with an implantable pump showed remarkable reductions in their postoperative hospital stay, rethrombosis, reoperation rate, and in-hospital mortality. An implantable pump of the portal vein in liver transplantation patients can prevent and facilitate the treatment of portal vein rethrombosis and is associated with a reduction of in-hospital mortality.

Portal vein thrombosis: Insight into physiopathology, diagnosis, and treatment

Portal vein thrombosis (PVT) is a relatively common complication in patients with liver cirrhosis, but might also occur in absence of an overt liver disease. Several causes, either local or systemic, might play an important role in PVT pathogenesis. Frequently, more than one risk factor could be identified; however, occasionally no single factor is discernable. Clinical examination, laboratory investigations, and imaging are helpful to provide a quick diagnosis, as prompt treatment might greatly affect a patient’s outcome. In this review, we analyze the physiopathological mechanisms of PVT development, together with the hemodynamic and functional alterations related to this condition. Moreover, we describe the principal factors most frequently involved in PVT development and the recent knowledge concerning diagnostic and therapeutic procedures. Finally, we analyze the implications of PVT in the setting of liver transplantation and its possible influence on patients’ future prognoses.

Multidetector computed tomography for preoperative assessment of hepatic vasculature and prediction of splenic artery steal syndrome in patients with liver cirrhosis before transplantation

The purpose of this study was to evaluate the accuracy of MDCT for preoperative assessment of hepatic vascular anatomy and the identification of liver-transplantation (OLT) patients at risk of developing subsequent splenic artery steal syndrome (SASS). A total of 145 patients with liver cirrhosis who had undergone OLT and had pre-operative three-phase MDCT (4- to 64-rows) within 100 days before OLT were enrolled retrospectively. MDCT and 3Ds were reviewed by two independent blinded observers (O1/O2). Pre-operative imaging findings were correlated with intra-operative results; findings indicative for SASS were correlated with clinical data and DSA. Among all 145 patients, 16 patients (11%) showed accessory hepatic arteries (accuracy O1/O2, 97%; with 3Ds, 100%); 32 (22%) patients had replaced hepatic arteries (accuracy O1, 97%; O2, 95%; with 3Ds, 100%; kappa = 0.87 and 0.89, P < 0.001). Among 119 patients, 12 patients developed SASS after OLT. The logistic regression model revealed the spleen volume (P = 0.0105) as a predictive factor of SASS. With spleen volumes >or=829 ml, an accuracy of 75% for prediction of SASS was obtained. MDCT with three-dimensional post-processing (3Ds) was highly accurate for pre-operative hepatic vessel evaluation in patients before OLT. In addition, spleen volume was a predictive factor for developing SASS after OLT.

Pre-existent portal vein thrombosis in liver transplantation: influence of pre-operative disease severity

BACKGROUND

Portal vein thrombosis (PVT) is a surgical challenge in liver transplantation (LTx). In contrast to LTx in decompensated liver disease, which are associated with a higher morbidity and mortality, PVT influence on outcome is still under debate. To evaluate this influence at different stages of liver decompensation, we compared the outcome of patients suffering from PVT to patients with patent portal vein within different score ranges.

METHODS

We included 193 LTx (24 with PVT) in our study, transplanted between 2004 and 2007 at our institution. Patients were divided into four Model of End-Stage Liver Disease (MELD) score groups, and outcome was compared between PVT- and non-PVT patients.

RESULTS

In non-decompensated liver disease (MELD <15), we found a significantly decreased survival in patients suffering from PVT (one-yr survival 57% vs. 89%). By contrast, MELD score >15 (decompensated liver disease) leads to an equal or even better survival in PVT-patients compared with patients without PVT (one-yr survival 91% vs.75%), with an only slightly increased morbidity.

CONCLUSION

Outcome in patients with PVT seems to be dependent on pre-operative disease severity. In contrast to compensated liver disease, no influence of PVT on outcome could be found in decompensated liver disease, and should therefore not be considered as a contraindication in LTx.

Thrombosis of the portal venous system

Portal vein thrombosis (PVT) is a rare cause of portal hypertension. Its diagnosis has been facilitated by improvements in imaging techniques, in particular Doppler sonography. The prevalence is about 1% in the general population, but much higher rates are observed in patients with hepatic cirrhosis (7%, range 0.6-17%), particularly those who also have hepatocellular carcinoma (HCC) (35%). The most common causes of PVT are myeloproliferative disorders, deficiencies of anticoagulant proteins, prothrombotic gene mutations, cirrhosis with portal hypertension, and HCC. Its development often requires the presence of two or more risk factors (local and/or systemic), e.g., a genetically determined thrombophilic state plus an infectious episode or abdominal surgery. It is clinically useful to distinguish between cirrhotic and noncirrhotic forms. Portal vein thrombosis is also traditionally classified as acute or chronic, but this distinction is often difficult. Color Doppler ultrasound is the first-line imaging study for diagnosis of PVT; magnetic resonance angiography and CT angiography are valid alternatives. The main complications are ischemic intestinal necrosis (in acute PVT) and esophageal varices (in chronic cases); the natural history of the latter differs depending on whether or not the thrombosis is associated with cirrhosis. The treatment of choice for PVT has never been adequately investigated. It is currently based on the use of anticoagulants associated, in some cases, with thrombolytics, but experience with the latter agents is too limited to draw any definite conclusions. In chronic thrombosis (even forms associated with cirrhosis), anticoagulant therapy is recommended and possibly, beta-blockers as well. Naturally, treatment of the underlying pathology is essential.

Liver transplantation in adult patients with portal vein thrombosis: risk factors, management and outcome

BACKGROUND

Portal vein thrombosis (PVT) is a well recognized complication of patients with end-stage cirrhosis and its incidence ranges from 2 to 26%. The aim of this study was to analyze the results and long-term follow-up of a consecutive series of liver transplants performed in patients with PVT and compare them with patients transplanted without PVT.

PATIENTS AND METHODS

Between July 1995 and June 2006, 26 liver transplants were performed in patients with PVT (8.7%). Risk factors and variables associated with the transplant and the post-transplant period were analyzed. A comparative analysis with 273 patients transplanted without PVT was performed.

RESULTS

The patients comprised 53.8% males, average age 40, 7 years. PVT was detected during surgery in 65%. Indications for transplantation were: post-necrotic cirrhosis 73%, cholestatic liver diseases 23%, and congenital liver fibrosis 4%. Child-Pugh C: 61.5%. Techniques were trombectomy in 21 patients with PVT grades I, II, IV, and extra-anatomical mesenteric graft in 5 with grade III. Morbidity was 57.7%, recurrence of PVT was 7.7%, and in-hospital mortality was 26.9%. Greater operative time, transfusion requirements, and re-operations were found in PVT patients. One-year survival was 59.6%: 75.2% for grade 1 and 44.8% for grades 2, 3, and 4.

DISCUSSION

The study demonstrated a PVT prevalence of 8.7%, a higher incidence of partial thrombosis (grade 1), and successful management of PVT grade 4 with thrombectomy. Liver transplant in PVT patients was associated with an increased operative time, transfusion requirements, re-interventions, and lower survival rate according to PVT extension.