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

Management of Portal vein Thrombosis in Cirrhosis

Portal vein thrombosis (PVT) is one of the common complications of cirrhosis. The incidence of PVT correlates with liver disease severity-higher incidence in patients with Child-Turcotte-Pugh (CTP) C, large spontaneous portosystemic shunts, hepatofugal portal flow, and in the presence of hepatocellular carcinoma. PVT may worsen ascites, increase the risk and poor control of variceal bleeding. The occurrence of PVT may increase morbidity and lower survival after a liver transplant. Using statins prevents the occurrence of PVT, whereas beta-blockers may aggravate its occurrence. Cross-sectional imaging is mandatory for the precise diagnosis and classification of PVT. Symptomatic, occlusive PVT and candidacy for liver transplantation are the main indications for anticoagulation. Vitamin K antagonists, low-molecular-weight heparin, and newer anticoagulants are effective and safe in cirrhosis. Direct-acting oral anticoagulants are agents of choice in early cirrhosis (CTP A, B). The duration of anticoagulant therapy, predictors of response, and management of complications of cirrhosis while on therapy require in-depth knowledge and individualized treatment. Transjugular intrahepatic porto-systemic shunt can be considered in nonresponsive cases or when anticoagulants are contraindicated. This manuscript reviews the latest updated knowledge about managing PVT in cirrhosis.

Impossible Yet Possible-Orthotopic Liver Transplantation in a Patient With Complete Portal Vein Thrombosis: A Case Report and Literature Review

This case study presents a liver transplantation (LT) in a patient with incidentally, intraoperatively detected complete portal vein thrombosis (PVT), classified as YERDEL stage 4, challenging traditional surgical boundaries. The patient's resilience and the innovative approach adopted by the surgical team exemplify the evolving complexities of LT in the context of advanced PVT. This report underscores the significance of detailed case documentation in medical literature, especially for complex transplant scenarios. It contributes to a broader understanding of surgical techniques and patient-centered approaches in LT. The narrative highlights the dynamic interplay between surgical advancements and vascular complications, advocating for the refinement of surgical methods and a reevaluation of conventional perspectives in transplantation. This case is pivotal in illustrating medical progress and the persistent pursuit of better outcomes in complex transplant situations.

Liver transplantation for severe hepatic trauma: A multicenter analysis from the UNOS data set

BACKGROUND

Orthotopic liver transplantation (OLT) is rarely indicated after hepatic trauma but it can be the only therapeutic option in some patients. There are scarce data analyzing the surgical outcomes of OLT after trauma.

METHODS

We used the UNOS data set to identify patients who underwent OLT for trauma from 1987 to 2022 and compared them to a cohort of patients transplanted for other indications. Cox proportional hazard and multivariable logistic regression analyses were performed to assess predictors of graft and patient survival.

RESULTS

Seventy-two patients underwent OLT for trauma during the study period. Patients with trauma were more frequently on mechanical ventilation at the time of transplantation (26.4% vs. 7.6%, p < 0.001) and had a greater incidence of pretransplant portal vein thrombosis (12.5% vs. 4%, p = 0.002). Our 4:1 matched analysis showed that trauma patients had significantly shorter wait times, higher incidence of pretransplant portal vein thrombosis and prolonged length of stay. Trauma was associated with decreased overall graft survival (hazards ratio, 1.42; 95% confidence interval, 1.01-1.98), and increased length of stay ( p = 0.048). There were no significant differences in long-term patient survival.

CONCLUSION

Unique physiological and vascular challenges after severe hepatic trauma might be associated with decreased graft survival in patients requiring liver transplantation.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level III.

Portal Vein Thrombosis: State-of-the-Art Review

Background: Portal vein thrombosis (PVT) is a rare disease with an estimated incidence of 2 to 4 cases per 100,000 inhabitants. The most common predisposing conditions for PVT are chronic liver diseases (cirrhosis), primary or secondary hepatobiliary malignancy, major infectious or inflammatory abdominal disease, or myeloproliferative disorders. Methods: PVT can be classified on the basis of the anatomical site, the degree of venous occlusion, and the timing and type of presentation. The main differential diagnosis of PVT, both acute and chronic, is malignant portal vein invasion, most frequently by hepatocarcinoma, or constriction (typically by pancreatic cancer or cholangiocarcinoma). Results: The management of PVT is based on anticoagulation and the treatment of predisposing conditions. The aim of anticoagulation in acute thrombosis is to prevent the extension of the clot and enable the recanalization of the vein to avoid the development of complications, such as intestinal infarction and portal hypertension. Conclusions: The treatment with anticoagulant therapy favors the reduction of portal hypertension, and this allows for a decrease in the risk of bleeding, especially in patients with esophageal varices. The anticoagulant treatment is generally recommended for at least three to six months. Prosecution of anticoagulation is advised until recanalization or lifelong if the patient has an underlying permanent pro-coagulant condition that cannot be corrected or if there is thrombosis extending to the mesenteric veins.

Natural history of portal vein thrombosis in cirrhosis: A systematic review with meta-analysis

BACKGROUND AND AIM

Progression of liver disease in cirrhosis is associated with an increased incidence of portal vein thrombosis (PVT) in cirrhosis. However, evidence suggests that spontaneous recanalization of PVT may occur even without anti-thrombotic therapy. Thus, the present meta-analysis was conducted to study the natural history of PVT in cirrhosis, facilitating decisions regarding anticoagulation.

METHODS

Three electronic databases were searched from 2000 to August 2022 for studies reporting the outcome of PVT in cirrhotics without anticoagulation. The pooled proportions with their 95% confidence intervals (CIs) were calculated using a random-effect model.

RESULTS

A total of 26 studies (n = 1441) were included in the final analysis. Progression of PVT on follow-up was seen in 22.2% (95% CI 16.1-28.4), while 77.7% (95% CI 71.6-83.9) remained non-progressive (improved or stable). The most common outcome was a stable PVT with a pooled event rate of 44.6% (95% CI 34.4-54.7). The pooled rates of regression and complete recanalization of PVT in cirrhotics were 29.3% (95% CI 20.9-37.7) and 10.4% (95% CI 5.0-15.8), respectively. On follow-up after improvement, pooled recurrence rate of PVT was 24.0% (95% CI 14.7-33.4). MELD score, and presence of ascites had a negative association, while a longer follow-up duration had positive association with PVT regression.

CONCLUSION

Approximately 25% of the cases of PVT in cirrhosis are progressive, 30% cases improve, and 45% remain stable. Future studies are needed to analyze the predictors of spontaneous regression.

Assessment of portal system hemodynamics for the prediction of portal vein thrombosis in cirrhosis-A systematic review and meta-analysis

BACKGROUND

The pathogenesis of portal vein thrombosis (PVT) in cirrhosis is multifactorial, with altered hemodynamics being proposed as a possible contributor. The present systematic review was conducted to study the role of assessment of portal hemodynamics for the prediction of PVT in patients with cirrhosis.

METHODS

Three databases (Medline, Embase, and Scopus) were searched from inception to February 2023 for studies comparing portal venous system parameters in patients with cirrhosis developing PVT with those not. Results were presented as mean difference (MD) or odds ratio (OR) with their 95% confidence intervals (CIs).

RESULTS

A total of 31 studies (patients with cirrhosis: 19 studies, patients with cirrhosis undergoing splenectomy: 12 studies) were included. On pooling the data from multivariable analyses of the included studies, a larger portal vein diameter was a significant predictor of PVT in patients with cirrhosis without or with splenectomy with OR 1.74 (1.12-2.69) and OR 1.55 (1.26-1.92), respectively. On the other hand, a lower portal vein velocity (PVV) was a significant predictor of PVT in cirrhotics without or with splenectomy with OR 0.93 (0.91-0.96) and OR 0.71 (0.61-0.83), respectively. A PVV of <15 cm/s was the most commonly used cut-off for the prediction of PVT. Patients developing PVT also had a significantly higher splenic length, thickness, and splenic vein velocity.

CONCLUSION

The assessment of portal hemodynamic parameters at baseline evaluation in patients with cirrhosis may predict the development of PVT. Further studies are required to determine the optimal cut-offs for various parameters.

Global research on portal vein thrombosis and liver transplantation: A bibliometric and visualized study

In recent years, the association between portal vein thrombosis and liver transplantation has extensive attention from physicians worldwide. However, there is no available literature on bibliometric analysis in this research area. Herein, we aimed to conduct a bibliometric analysis to identify the hotspots and frontiers of research related to portal vein thrombosis and liver transplantation. Documents published between 2002 and 2022 were retrieved and downloaded from the Web of Science Core Collection database. VOSviewer was utilized to generate a visualization network map of authors, nations, institutions, journals, and keyword co-occurrence/clustering. Additionaly, CiteSpace was used to analyze the keywords with the strongest bursts. A total of 1272 articles and reviews were extracted from the database. The author Marco Senzolo published the largest number of papers. The United States was the most prolific country, and Hope-Bochon (France) was the top productive institution. Liver Transplantation was the most prolific journal in the field. The most commonly identified keywords in the study were cirrhosis, risk factors, portal vein thrombosis, and management, as revealed by the keyword co-occurrence analysis. It is suggested that patients with cirrhosis, portal vein thrombosis prevention, and management measures for portal vein thrombosis have been prominet topics in recent years. Furthermore, an analysis of keywords with the strongest citation bursts highlighted pediatric liver transplantation, direct oral anticoagulants, and nonalcoholic fatty liver disease as current research trends. Research in portal vein thrombosis and liver transplantation exhibits a general upward trend. The latest hot topics within this area of study involve pediatric patients and nonalcoholic fatty liver disease.

Anti-Inflammatory and Anti-Thrombogenic Properties of Arterial Elastic Laminae

Elastic laminae, an elastin-based, layered extracellular matrix structure in the media of arteries, can inhibit leukocyte adhesion and vascular smooth muscle cell proliferation and migration, exhibiting anti-inflammatory and anti-thrombogenic properties. These properties prevent inflammatory and thrombogenic activities in the arterial media, constituting a mechanism for the maintenance of the structural integrity of the arterial wall in vascular disorders. The biological basis for these properties is the elastin-induced activation of inhibitory signaling pathways, involving the inhibitory cell receptor signal regulatory protein α (SIRPα) and Src homology 2 domain-containing protein tyrosine phosphatase 1 (SHP1). The activation of these molecules causes deactivation of cell adhesion- and proliferation-regulatory signaling mechanisms. Given such anti-inflammatory and anti-thrombogenic properties, elastic laminae and elastin-based materials have potential for use in vascular reconstruction.

Anticoagulation in Patients with Liver Cirrhosis: Friend or Foe?

Concepts regarding the status of the coagulation process in cirrhosis are rapidly changing. Instead of a disease defined by excessive bleeding risk, recent studies have shown cirrhosis to be associated with a fragile state of rebalanced hemostasis, easily swayed in either direction, thrombosis, or bleeding. These findings, combined with the ever-growing population of patients with cirrhosis with an indication for anticoagulation (AC) and the emergence of the non-alcoholic fatty liver disease epidemic, have prompted a reexamination of the use of AC in patients with cirrhosis, either as a treatment for a concurrent thrombotic disorder or even as a possible therapeutic option that could influence the natural course of the disease and its complications. In recent years, a significant number of studies have been formulated to evaluate these possibilities. These studies evaluated, among others, the efficacy and safety of AC in thrombotic disorders or thrombotic complications of cirrhosis, its effect on survival, and the class of anticoagulants which is more suitable for patients with cirrhosis, depending on disease severity. This review examines recent studies investigating the use of AC in patients with cirrhosis and attempts to provide a simple guide for clinicians regarding the use of AC in patients with cirrhosis and its potential risks and benefits.

Liver Transplantation in Patients with Portal Vein Thrombosis: Revisiting Outcomes According to Surgical Techniques

Surgical strategies for graft portal vein flow restoration vary from termino-terminal portal vein anastomosis to more complex bypass reconstructions. Although the surgical strategy strongly influences the post-operative outcome, the Yerdel grading is still commonly used to determine the prognosis of patients with portal vein thrombosis (PVT) undergoing liver transplantation (LT). We retrospectively reviewed the cases of LT performed on recipients with complex PVT at two high-volume transplantation centres. We stratified the patients by the type of portal vein reconstruction, termino-terminal portal vein anastomosis (TTA) versus bypass reconstruction (bypass group), and assessed a multivariable survival analysis. The rate of mortality at 90 days was 21.4% for the bypass group compared to 9.8% in the TTA group (p = 0.05). In the multivariable correlation analysis, only a trend for greater risk of early mortality was confirmed in the bypass groups (HR 2.5; p = 0.059). Yerdel grade was uninfluential in the rate of early complications. A wide range of surgical options are available for different situations of PVT which yield an outcome unrelated to the Yerdel grading. An algorithm for PVT management should be based on the technical approach and should include a surgically oriented definition of PVT extension.