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

Portal Vein Thrombosis Is a Risk Factor for Poor Early Outcomes After Liver Transplantation: Analysis of Risk Factors and Outcomes for Portal Vein Thrombosis in Waitlisted Patients

BACKGROUND

Portal vein thrombosis (PVT) is common in patients with cirrhosis, but the risk factors associated with PVT and its impact on outcomes following liver transplantation (LT) are not well defined. The objectives of this study were to determine the impact of PVT on post-LT patient and graft survival, waitlist outcomes, and the factors associated with PVT.

METHODS

A retrospective review of Organ Procurement and Transplant Network waitlist and LT data between 2002 and 2013 identified 48,570 patients undergoing their first LT, with 3321 (6.8%) reported to have PVT at LT.

RESULTS

Portal vein thrombosis was independently associated with increased 90-day mortality (odds ratio, 1.7; 95% confidence interval, 1.45-1.99; P < 0.001) and graft failure (odds ratio, 1.72; 95% confidence interval, 1.51-1.97; P < 0.001). Portal vein thrombosis at listing was not associated with lower transplant rates, or delisting for death, or deterioration. Only 31% of patients with PVT at LT had PVT reported at listing. The predictors of PVT at LT in patients without PVT at listing included: fatty or cryptogenic liver disease, ascites, diabetes mellitus, and obesity. "New" PVT at LT was associated with longer wait-time, higher rate of model of end-stage liver disease increase, and intermediate 90-day survival rates compared to patients with or without PVT at both listing and LT.

CONCLUSIONS

Portal vein thrombosis at LT is associated with early (90 days) mortality and graft failure, though a likely but undefined reporting bias for more extensive PVT would overstate estimated risks for all PVT. Further study is needed to better define risks of LT with PVT.

Portal Vein Recanalization and Transjugular Intrahepatic Portosystemic Shunt Creation for Chronic Portal Vein Thrombosis: Technical Considerations

Portal vein thrombosis (PVT) is common in cirrhotic patients and presents a challenge at the time of transplant. Owing to the increased posttransplant morbidity and mortality associated with complete PVT, the presence of PVT is a relative contraindication to liver transplantation at many centers. Our group began performing portal vein (PV) recanalization and transjugular intrahepatic portostystemic shunt placement (PVR-TIPS) several years ago to optimize the transplant candidacy of patients with PVT. The procedure has evolved to include transsplenic access to assist with recanalization, which is now our preferred method due to its technical success without significant added morbidity. Here, we describe in detail our approach to PVR-TIPS with a focus on the transsplenic method. The procedure was attempted in 61 patients and was technically successful in 60 patients (98%). After transitioning to transsplenic access to assist with recanalization, the technical success rate has improved to 100%. The recanalized portal vein and TIPS have maintained patency during follow-up, or to the time of transplant, in 55 patients (92%) with a mean follow-up of 16.7 months. In total, 23 patients (38%) have undergone transplant, all of whom received a physiologic anastomosis (end-to-end anastomosis in 22 of 23 patients, 96%). PVR-TIPS placement should be considered as an option for patients with chronic PVT in need of transplantation. Transsplenic access makes the procedure technically straightforward and should be considered as the primary method for recanalization.

Portal Vein Thrombosis in Patients with Hepatocellular Carcinoma: Diagnostic Accuracy of Gadoxetic Acid-enhanced MR Imaging

Purpose To assess the diagnostic performance of gadoxetic acid-enhanced magnetic resonance (MR) imaging in the evaluation of portal vein thrombosis (PVT) in patients with hepatocellular carcinoma (HCC). Materials and Methods This retrospective study was approved by the institutional review board. The requirement to obtain informed consent was waived. A total of 366 patients with HCC who underwent gadoxetic acid-enhanced MR imaging between January 2007 and May 2013, including 134 with malignant PVT, 49 with benign PVT, and 183 without PVT matched for age and sex, comprised our study population. PVTs were complete in 125 patients and partial in 58 and were located in a major portal vein (n = 159) or segmental portal vein (n = 24). Two radiologists independently reviewed the MR images and assessed the sensitivity, specificity, and accuracy in the detection and characterization of PVT according to location (major vs segmental) and type (complete vs partial). The Fisher exact or χ(2) test was used to evaluate sensitivity difference between the subsets. Results Gadoxetic acid-enhanced MR imaging showed good sensitivity (reviewer 1, 84% [154 of 183 patients]; reviewer 2, 70% [129 of 183 patients]) and high specificity (reviewer 1, 89% [163 of 183 patients]; reviewer 2, 96% [176 of 183 patients]) in the detection of PVT. Diagnostic accuracy for differentiating malignant PVT from benign PVT was high (reviewer 1, 92% [141 of 154 patients]; reviewer 2, 95% [122 of 129 patients]). However, there was slightly lower sensitivity for detecting segmental PVT compared with that of major PVT in the malignant PVT group (reviewer 1, 95% [104 of 110 patients] vs 88% [21 of 24 patients]; reviewer 2, 82% [90 of 110 patients] vs 79% [19 of 24 patients]; P = .203 and .775 for reviewers 1 and 2, respectively). Conclusion Gadoxetic acid-enhanced MR imaging provided good diagnostic performance in the detection of PVT and the differentiation of malignant from benign PVT in patients with HCC. However, caution is needed when evaluating potential candidates for curative treatment because of the low sensitivity for segmental PVT in the malignant PVT group. (©) RSNA, 2016 Online supplemental material is available for this article.

Therapy Algorithm for Portal Vein Thrombosis in Liver Cirrhosis: The Internist's Point of View

BACKGROUND

Treatment of non-malignant portal vein thrombosis (PVT) in patients with cirrhosis has been neglected in the past because of the fear of bleeding complications when using anticoagulation and due to the technical difficulties associated with the implantation of the transjugular intrahepatic portosystemic shunt (TIPS). However, PVT has a negative impact on outcome and compromises liver transplantation, warranting treatment by using anticoagulation and TIPS.

METHODS

This review considers studies on the treatment of PVT in cirrhosis published in the last 10 years. Unfortunately, many of these studies are limited by their retrospective design and a small sample size.

RESULTS

Anticoagulation using low-molecular-weight heparin (LMWH) or vitamin K antagonists is effective in the treatment of patients with limited and recent PVT, resulting in a recanalization in up to 50% of the patients. TIPS (plus local measures) results in a recanalization of up to 100% and reduces the rebleeding rate considerably in patients with recent or chronic PVT.

CONCLUSION

Based on the presently limited knowledge, a therapy algorithm is suggested favouring the TIPS as a first-line treatment for PVT in patients with symptomatic portal hypertension. Patients with thus far asymptomatic portal hypertension may first receive anticoagulation, preferably using LMWH. If these patients have a condition where anticoagulation is not promising (complete, extended, chronic PVT) or ineffective, or if they are candidates for liver transplantation, the TIPS may be implanted without delay.

Nonsurgical Therapeutic Options in Portal Vein Thrombosis

Background

Portal vein thrombosis (PVT) is a rare but severe vascular disorder with an acute and a chronic course. Most patients have underlying liver cirrhosis; furthermore, thrombophilia is an important risk factor. However, idiopathic forms are also known.

Methods

This review discusses nonsurgical treatment options in PVT.

Results and Conclusion

Therapy of acute PVT is based on anticoagulation with heparin that is switched to oral anticoagulants, if applicable. Catheter-guided invasive therapy should be considered; however, patients with liver cirrhosis should be screened for portal hypertension before anticoagulation is mandatory. Therapy of chronic PVT is discussed controversially; therefore, a strict patient selection and an individual therapeutic decision are warranted depending on the etiology of PVT. Special forms of PVT including septic and malignant thrombosis as well as PVT in patients waiting for liver transplantation require particular therapy algorithms.

Portal vein thrombosis

Portal vein thrombosis is an important cause of portal hypertension. PVT occurs in association with cirrhosis or as a result of malignant invasion by hepatocellular carcinoma or even in the absence of associated liver disease. With the current research into its genesis, majority now have an underlying prothrombotic state detectable. Endothelial activation and stagnant portal blood flow also contribute to formation of the thrombus. Acute non-cirrhotic PVT, chronic PVT (EHPVO), and portal vein thrombosis in cirrhosis are the three main variants of portal vein thrombosis with varying etiological factors and variability in presentation and management. Procoagulant state should be actively investigated. Anticoagulation is the mainstay of therapy for acute non-cirrhotic PVT, with supporting evidence for its use in cirrhotic population as well. Chronic PVT (EHPVO) on the other hand requires the management of portal hypertension as such and with role for anticoagulation in the setting of underlying prothrombotic state, however data is awaited in those with no underlying prothrombotic states. TIPS and liver transplant may be feasible even in the setting of PVT however proper selection of candidates and type of surgery is warranted. Thrombolysis and thrombectomy have some role. TARE is a new modality for management of HCC with portal vein invasion.

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.

High early cardiovascular mortality after liver transplantation

Cardiovascular disease (CVD) contributes to excessive long-term mortality after liver transplantation (LT); however, little is known about early postoperative CVD mortality in the current era. In addition, there is no model for predicting early postoperative CVD mortality across centers. We analyzed adult recipients of primary LT in the Organ Procurement and Transplantation Network (OPTN) database between February 2002 and December 2012 to assess the prevalence and predictors of early (30-day) CVD mortality, which was defined as death from arrhythmia, heart failure, myocardial infarction, cardiac arrest, thromboembolism, and/or stroke. We performed logistic regression with stepwise selection to develop a predictive model of early CVD mortality. Sex and center volume were forced into the final model, which was validated with bootstrapping techniques. Among 54,697 LT recipients, there were 1576 deaths (2.9%) within 30 days. CVD death was the leading cause of 30-day mortality (40.2%), and it was followed by infection (27.9%) and graft failure (12.2%). In a multivariate analysis, 9 significant covariates (6 recipient covariates, 2 donor covariates, and 1 operative covariate) were identified: age, preoperative hospitalization, intensive care unit status, ventilator status, calculated Model for End-Stage Liver Disease score, portal vein thrombosis, national organ sharing, donor body mass index, and cold ischemia time. The model showed moderate discrimination (C statistic = 0.66, 95% confidence interval = 0.63-0.68). In conclusion, we provide the first multicenter prognostic model for the prediction of early post-LT CVD death, the most common cause of early post-LT mortality in the current transplant era. However, evaluations of additional CVD-related variables not collected by the OPTN are needed in order to improve the model's accuracy and potential clinical utility.

Sonographic Evaluation of a Cavoportal Hemitransposition Liver Transplant

Extensive portal vein thrombosis is no longer considered a contraindication for liver transplantation. With cavoportal hemitransposition (portal diversion) or other surgical techniques, patients with portal vein thrombosis who would otherwise succumb to their liver disease are able to receive a transplant. A series of three cases is presented describing the evaluation and liver transplant procedures in patients with portal vein thrombosis. Sonography is shown to be an important tool both for diagnosing portal vein thrombosis and evaluating the portal system following transplantation.

Coagulopathy in liver diseases: complication or therapy?

Coagulopathy in cirrhosis is a composite condition where liver synthetic deficit rebalances coagulation to a parallel reduction of both pro- and anticoagulant factors. Cirrhosis is therefore no longer considered a hypocoagulable state but rather a more unstable hemostatic balance with a lower threshold for tipping toward thrombosis or bleeding. Tendency to bleeding in cirrhosis is due to the reduction in the synthesis of procoagulants and a low platelet count as well as hyperfibrinolysis. Variceal hemorrhage is a frequent bleeding complication in decompensated cirrhosis. However, the possible contribution of coagulopathy as a precipitant or an aggravating factor is poorly documented and further data are required to clarify its real contributing role. Moreover, apart from the gastrointestinal tract, the occurrence of spontaneous and procedure-related bleeding elsewhere in the body, whilst not uncommon, is less than would be expected. By contrast, a large-scale population-based study has shown the propensity towards venous thrombosis in patients with liver diseases. Portal vein thrombosis (PVT) is a critical but frequent event occurring in up to 40% of patients with liver cirrhosis. PVT causes deterioration of the clinical course, the complications of portal hypertension and an increase in post-transplant mortality. The pathogenesis of PVT includes both local alterations, like blood flow reduction and endothelial activation, and systemic derangement. Systemic prohemostatic alterations include high von Willebrand factor, low ADAMTS-13, low levels of anticoagulants (antithrombin, proteins C and S) and increases in procoagulants like factor VIII. Low-molecular-weight heparin such as enoxaparin has proven to be safe and effective in both the treatment and prevention of PVT. In addition, patients in prophylaxis with enoxaparin showed a lower rate of decompensation and a better survival without bleeding complications. In such patients, circulating bacterial DNA, endotoxemia and markers of inflammation were attenuated compared to controls. These results therefore suggest a possible connection between enoxaparin, decrease of endotoxemia and reduction of portal hypertension. The approach to the coagulopathy in patients with liver diseases is changing: while the main goal for clinicians so far has been to reduce the risk of bleeding, the results of these new studies highlight the importance of preventing or treating thrombophilic disorders like PVT to avoid microcirculatory damage and eventually liver decompensation.

Management of portal vein thrombosis in liver cirrhosis

Portal vein thrombosis (PVT) is a fairly common complication of liver cirrhosis. Importantly, occlusive PVT might influence the prognosis of patients with cirrhosis. Evidence from a randomized controlled trial has shown that anticoagulation can prevent the occurrence of PVT in patients with cirrhosis without prior PVT. Evidence from several case series has also demonstrated that anticoagulation can achieve portal vein recanalization in patients with cirrhosis and PVT. Early initiation of anticoagulation therapy and absence of previous portal hypertensive bleeding might be positively associated with a high rate of portal vein recanalization after anticoagulation. However, the possibility of spontaneous resolution of partial PVT questions the necessity of anticoagulation for the treatment of partial PVT. In addition, a relatively low recanalization rate of complete PVT after anticoagulation therapy suggests its limited usefulness in patients with complete PVT. Successful insertion of a transjugular intrahepatic portosystemic shunt (TIPS) not only recanalizes the thrombosed portal vein, but also relieves the symptomatic portal hypertension. However, the technical difficulty of TIPS potentially limits its widespread application, and the risk and benefits should be fully balanced. Notably, current recommendations regarding the management of PVT in liver cirrhosis are insufficient owing to low-quality evidence.

When and why portal vein thrombosis matters in liver transplantation: a critical audit of 174 cases

OBJECTIVE

To identify complications associated with different techniques utilized to treat portal vein thrombosis (PVT) during primary liver transplantation and their impact on survival.

BACKGROUND

PVT remains an intricate problem in liver transplantation, and the long-term outcomes of patients with PVT who undergo transplantation are not well defined.

METHODS

We performed a retrospective cohort analysis of all consecutive adult patients who underwent primary isolated liver transplantation from 1998 to 2009 (median follow-up period, 89 months). The outcomes of patients with PVT were compared with those without PVT.

RESULTS

Among 1379 recipients, 174 (12.6%) had PVT at the time of transplantation [83 (48%) complete and 91 (52%) partial]. Among PVT patients with reestablished physiological portal inflow (PVT: physiological group; n = 149), 123 underwent thrombectomies, 16 received interpositional vein grafts, and 10 received mesoportal jump grafts. In 25 patients, physiological portomesenteric venous circulation was not reconstituted (PVT: nonphysiological group; 18 underwent cavoportal hemitranspositions, 6 renoportal anastomoses, and 1 arterialization). The PVT: nonphysiological group suffered a significantly increased incidence of rethrombosis of the portomesenteric veins and gastrointestinal bleeding, with a marginal 10-year overall survival rate of 42% (no PVT, 61%; P = 0.002 and PVT: physiological, 55%; P = 0.043). The PVT: physiological and no PVT groups exhibited comparable survival rates (P = 0.13). No significant differences in survival were observed between complete and partial PVT as long as physiological portal flow was reestablished.

CONCLUSIONS

The subset of PVT patients requiring nonphysiological portal vein reconstruction was associated with higher complication rates and suffered diminished long-term prognoses. For the most severe PVT cases, a comprehensive approach is critical to further improve outcomes.

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.

Portal vein thrombosis in liver cirrhosis

Portal vein thrombosis (PVT) is considered to be a frequent complication of liver cirrhosis. However, unlike PVT in patients without cirrhosis, very few data are available on the natural history and management of PVT in cirrhosis, despite its association with potentially life-threatening conditions, such as gastroesophageal bleeding and acute intestinal ischemia. Moreover, no consensus regarding PVT in cirrhosis exists. Suggested causes of PVT in cirrhosis include reduced portal blood flow velocity, multiple congenital or acquired thrombophilic factors, inherited or acquired conditions, and derangement of liver architecture. However, the understanding of PVT in cirrhosis is incomplete. In addition, information on the management of PVT in cirrhosis is inadequate. The aims of this review are to: (1) assemble data on the physiopathological mechanism, clinical findings, diagnosis and management of PVT in cirrhosis; (2) describe the principal factors most frequently involved in PVT development; and (3) summarize the recent knowledge concerning diagnostic and therapeutic procedures.

Liver in haematological disorders

Prothrombotic haematological disorders, in particular myeloproliferative disorders, are identified in a significant proportion of patients with Budd-Chiari syndrome and portal vein thrombosis (PVT). Multiple prothrombotic disorders may coexist. PVT is diagnosed in one fourth of patients with cirrhosis and is more common with advanced liver disease and hepatocellular carcinoma. PVT in cirrhosis can precipitate decompensation. Intrahepatic microthrombosis may play a role in the pathogenesis of hepatic fibrosis. Sinusoidal obstruction syndrome is usually a complication of myeloablative treatment before haematopoietic stem cell transplantation. Post-transplant lymphoproliferative disorders can complicate liver transplantation and are related to Epstein-Barr virus infection. Hepatitis B reactivation in patients receiving chemotherapy for haematological malignancies is very common without pre-emptive treatment, and can lead to liver failure. Liver involvement is common in primary haematological diseases, such as haemolytic anaemias, lymphomas and leukaemia.

Evidence that low protein C contributes to the procoagulant imbalance in cirrhosis

BACKGROUND & AIMS

Cirrhosis is associated with a plasmatic procoagulant imbalance, detected in vitro by thrombin generation tests performed in the presence vs. absence of such activators of protein C as thrombomodulin or Protac. This imbalance is thought to be due to decreased protein C and increased factor VIII, but this has never been directly demonstrated. To test this hypothesis we analyzed plasma from 50 patients with cirrhosis before and after in vitro addition of purified protein C meant to restore normal levels.

METHODS

Results for two thrombin generation assays were expressed as ratios of endogenous thrombin potential (ETP) with-to-without thrombomodulin or as Protac-induced coagulation inhibition (PICI%). By definition, high ETP ratios or low PICI% reflect a resistance to the anticoagulant action of thrombomodulin or Protac, respectively, and can be taken as indexes of in vitro procoagulant imbalance.

RESULTS

The median (range) protein C level before addition was 40% (4-101%) and increased to 156% (110-305) after addition (p<0.001). The procoagulant imbalance, which was high before protein C addition [ETP ratio=0.83 (0.44-1.00)], was reduced after addition [ETP ratio=0.60 (0.14-0.84)], p<0.001. ETP-ratios were inversely correlated with protein C activity (rho=-0.46, p<0.001). Similar results were obtained with the Protac assay.

CONCLUSIONS

The results provide evidence that low protein C contributes to the procoagulant imbalance in plasma from patients with cirrhosis. The findings may have clinical implications for the treatment or prophylaxis of thrombosis in these patients.

Portal vein thrombosis: should anticoagulation be used?

Portal vein thrombosis (PVT) can contribute to significant morbidity and mortality; in patients with cirrhosis, this can make transplant more technically challenging. Additionally, the clot may extend further into the mesenteric and splenic veins, and disturbance of the hepatic blood flow may lead to faster progression of the cirrhosis. Development of PVT is associated with local risk factors, and many patients have associated systemic prothrombotic factors. Anticoagulation in noncirrhotic patients should be initiated at diagnosis, using low-molecular-weight heparin overlapping with vitamin K antagonists. Cirrhotic patients with PVT should be screened for varices and then anticoagulated with low-molecular-weight heparin for at least a 6-month period. All patients should be assessed for triggering factors and tumors, as well as systemic prothrombotic factors. Newer evidence suggests that prophylactic anticoagulation in patients with cirrhosis may have a role in clinical management with decreased incidence of PVT and improved survival; further study is needed.

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.

Clinical factors predicting readmission after orthotopic liver transplantation

Hospitals with the highest readmission rates for high-cost conditions may be targeted for payment penalties. The primary aim of this study was to determine clinical predictors of 30-day readmission after discharge for patients undergoing orthotopic liver transplantation (OLT) at the University of Washington from January 2003 to October 2010. Secondary aims included the determination of predictors of institutional care after OLT and differences in survival between patients requiring 30-day readmission and patients not requiring 30-day readmission. Sixty-five of 766 discharged OLT patients (8.6%) required institutional care on discharge; 318 of the 701 remaining patients (45%) were readmitted within 30 days. The predictors of readmission included hospitalization within the 90 days before OLT [29.6% versus 18.4%, relative risk (RR) = 1.33, P = 0.04], pre-OLT portal vein thrombosis (7.9% versus 4.4%, RR = 1.76, P = 0.01), a creatinine level > 1.9 mg/dL (23.9% versus 11.5%, RR = 2.1, P ≤ 0.01), an albumin level < 2.6 mg/dL (51.9% versus 37.6%, RR = 1.57, P < 0.01), postoperative complications (38.7% versus 30.2%, RR = 1.31, P = 0.04), and a high school education or less (14.5% versus 10%, RR = 1.41, P = 0.04). One year after OLT, decreased survival was found for patients requiring 30-day readmission versus patients not requiring readmission (88.2% versus 95.6%, P < 0.05). In conclusion, this study has identified patients at high risk of readmission who may benefit from medical optimization.

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.

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.

Model for end-stage liver disease-based allocation system for liver transplantation in Argentina: does it work outside the United States?

BACKGROUND

In July 2005, Argentina was the first country after the United States to adopt the MELD system. The purpose of the present study was to analyse the impact of this new system on the adult liver waiting list (WL).

METHODS

Between 2005 and 2009, 1773 adult patients were listed for liver transplantation: 150 emergencies and 1623 electives. Elective patients were categorized using the MELD system. A prospective database was used to analyse mortality and probability to be transplanted (PTBT) on the WL.

RESULTS

The waiting time increased inversely with the MELD score and PTBT positively correlated with MELD score. With scores >/= 18 the PTBT remained over 50%. However, the largest MELD subgroup with <10 points (n = 433) had the lower PTBT (3%). In contrast, patients with T(2) hepatocellular carcinoma benefited excessively with the highest PTBT (84.2%) and the lowest mortality rate (5.4%). The WL mortality increased after MELD adoption (10% vs. 14.8% vs. P < 0.01). Patients with <10 MELD points had >fourfold probability of dying on the WL than PTBT (14.3% vs. 3%; P < 0.0001).

CONCLUSIONS

After MELD implementation, WL mortality increased and most patients who died had a low MELD score. A comprehensive revision of the MELD system must be performed to include cultural and socio-economical variables that could affect each country individually.

Detection of the imbalance of procoagulant versus anticoagulant factors in cirrhosis by a simple laboratory method

Patients with cirrhosis possess an imbalance in procoagulant versus anticoagulant activity due to increased factor VIII and decreased protein C. This imbalance can be detected by thrombin-generation assays performed in the presence/absence of thrombomodulin (predicate assay) that are not readily available in clinical laboratories. We sought to assess this hypercoagulability with a simpler thrombin-generation assay performed in the presence/absence of Protac, a snake venom that activates protein C in a manner similar to thrombomodulin (new assay). We analyzed blood from 105 patients with cirrhosis and 105 healthy subjects (controls). Results for the predicate-assay or the new-assay were expressed as ratio (with:without thrombomodulin) or as Protac-induced coagulation inhibition (PICI%). By definition, high ratios or low PICI% translate into hypercoagulability. The median(range) PICI% was lower in patients (74% [31%-97%]) than controls (93% [72%-99%]; P < 0.001), indicating that patients with cirrhosis are resistant to the action of Protac. This resistance resulted in greater plasma hypercoagulability in patients who were Child class C than those who were A or B. The hypercoagulability of Child C cirrhosis (63% [31%-92%]) was similar to that observed for patients with factor V Leiden (69% [15%-80%]; P = 0.59). The PICI% values were correlated with the levels of protein C (rho = 0.728, P < 0.001) or factor VIII (rho = -0.517, P < 0.001). Finally, the PICI% values were correlated with the predicate assay (rho = -0.580, P < 0.001).

CONCLUSION

The hypercoagulability of plasma from patients with cirrhosis can be detected with the new assay, which compares favorably with the other markers of hypercoagulability (i.e., high factor VIII and low protein C) and with the predicate-assay based on thrombin-generation with/without thrombomodulin. Advantages of the new assay over the predicate assay are easy performance and standardized results. Prospective trials are needed to ascertain whether it is useful to predict thrombosis in patients with cirrhosis.

Portal vein thrombosis, revisited

This review article aims to discuss the aetiology, pathophysiology, clinical presentation, diagnostic workup and management of portal vein thrombosis, either as a primary vascular liver disease in adults and children, or as a complication of liver cirrhosis. In addition, indications and limits of anticoagulant therapy are discussed in detail.

Systematic review: portal vein thrombosis in cirrhosis

BACKGROUND

As current imaging techniques in cirrhosis allow detection of asymptomatic portal vein thrombosis during routine ultrasonography, more patients with cirrhosis are diagnosed with portal vein thrombosis. Although a consensus on noncirrhotic extra-hepatic portal vein thrombosis has been published, no such consensus exists for portal vein thrombosis with cirrhosis.

AIM

To perform a systematic review of nonmalignant portal vein thrombosis in cirrhosis in terms of prevalence, pathogenesis, diagnosis, clinical course and management.

METHODS

Studies were identified by a search strategy using MEDLINE and EMBASE.

RESULTS

Portal vein thrombosis is encountered in 10-25% of cirrhotics. In terms of pathophysiology, cirrhosis is no longer considered a hypocoagulable state; rather than a bleeding risk in cirrhosis, various clinical studies support a thrombotic potential. Clinical findings of portal vein thrombosis in cirrhosis vary from asymptomatic disease to a life-threatening condition at first presentation. Optimal management of portal vein thrombosis in cirrhosis is currently not addressed in any consensus publication. Treatment strategies most often include the use of anticoagulation, while thrombectomy and transjugular intrahepatic portosystemic shunts are considered second-line options.

CONCLUSIONS

Portal vein thrombosis in cirrhosis has many unresolved issues, which are often the critical problems clinicians encounter in their everyday practice. We propose a possible research agenda to address these unresolved issues.

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.

Review article: the modern management of portal vein thrombosis

BACKGROUND

Portal vein thrombosis (PVT) is an important cause of portal hypertension. It may occur as such with or without associated cirrhosis and hepatocellular carcinoma. Information on its management is scanty.

AIM

To provide an update on the modern management of portal vein thrombosis. Information on portal vein thrombosis in patients with and without cirrhosis and hepatocellular carcinoma is also updated.

METHODS

A pubmed search was performed to identify the literature using search items portal vein thrombosis-aetiology and treatment and portal vein thrombosis in cirrhosis and hepatocellular carcinoma.

RESULTS

Portal vein thrombosis occurs because of local inflammatory conditions in the abdomen and prothrombotic factors. Acute portal vein thrombosis is usually symptomatic when associated with cirrhosis and/or superior mesenteric vein thrombosis. Anticoagulation should be given for 3-6 months if detected early. If prothrombotic factors are identified, anticoagulation should be given lifelong. Chronic portal vein thrombosis usually presents with well tolerated upper gastrointestinal bleed. It is diagnosed by imaging, which demonstrates a portal cavernoma in place of a portal vein. Anticoagulation does not have a definite role, but bleeds can be treated with endotherapy or shunt surgery. Rarely liver transplantation may be considered.

CONCLUSION

Role of anticoagulation in chronic portal vein thrombosis needs to be further studied.

Adult to pediatric living donor liver transplantation for portal cavernoma

AIM

Portal cavernoma (PC) is an important cause of non-cirrhotic portal hypertension with severe complications, such as variceal hemorrhage in pediatric patients. With the development of new surgical techniques, living donor liver transplantation (LDLT) has recently been recognized as a viable but challenging treatment option for PC. The purpose of the present study was to summarize the efficacy of LDLT in PC patients and to carry out a follow-up study of pediatric recipients.

METHODS

The primary indication for LDLT in our research was PC with severe variceal bleeding and liver function decompensation. Three patients were diagnosed with PC following evaluation with computed tomography angiography and abdominal color Doppler ultrasonography (CDU).

RESULTS

Various surgical techniques, including jump bypass grafting for portal vein anastomosis, were carried out according to the range and degree of cavernous transformation within the splenic vein and superior mesenteric vein. Postoperative CDU confirmed the early integrity of the portal vein (PV) in each patient. PV rethrombosis occurred in one patient 7 days after LDLT, despite anticoagulation therapy with coumadin. Two of the three patients had no further episodes of variceal hemorrhage during the 2-year follow-up period.

CONCLUSIONS

The present study is the first report of the successful use of LDLT to treat pediatric PC patients. We conclude that LDLT is effective for the majority of pediatric patients with PC.

Severe thrombocytopenia before liver transplantation is associated with delayed recovery of thrombocytopenia regardless of donor type

AIM: To compare the recovery of thrombocytopenia and splenomegaly during long-term follow-up after liver transplantation in patients receiving a living donor transplant or a cadaveric donor transplant.

METHODS: This was a retrospective cohort study of 216 consecutive liver transplant patients who survived for > 6 mo after transplantation; 169 received a liver transplant from a living donor and 47 from a cadaveric donor. The platelet counts or spleen volumes were examined before transplant, 1, 6, and 12 mo after transplant, and then annually until 5 years after transplant.

RESULTS: The mean follow-up period was 49 mo (range, 21-66). Platelet counts increased continuously for 5 years after orthotopic liver transplant. The restoration of platelet counts after transplant was significantly slower in patients with severe pretransplant thrombocytopenia (< 50 000/μL) until 4 years after transplant (P = 0.005). Donor type did not significantly affect the recovery of platelet count and spleen volume in either patient group. In multivariate analysis, pretransplant severe thrombocytopenia (< 50 000/μL) was an independent factor associated with sustained thrombocytopenia (P < 0.001, odds ratio 6.314; confidence interval, 2.828-14.095). Thrombocytopenia reappeared after transplant in seven patients with portal flow disturbance near the anastomosis site.

CONCLUSION: Our study suggests that severe thrombocytopenia before transplant is closely associated with delayed recovery of platelet count after transplant and donor type did not affect the recovery of thrombocytopenia. The reappearance of thrombocytopenia after transplant should be considered a possible indicator of flow disturbance in the portal vein.