Elevated levels of von Willebrand Factor in cirrhosis support platelet adhesion despite reduced functional capacity

Rotational thromboelastometry predicts future bleeding events in patients with cirrhosis

BACKGROUND AND AIMS

Patients with cirrhosis of the liver are in a delicate state of rebalanced haemostasis and are at risk of developing both bleeding and thrombotic complications. Conventional haemostatic tests are unable to predict bleeding and thrombosis in these patients. We aimed to explore the role of Rotational Thromboelastometry (ROTEM) in predicting bleeding and thrombotic events in patients with cirrhosis.

METHODS

We conducted a prospective cohort study of patients with cirrhosis at two metropolitan hospitals. All patients underwent ROTEM analysis and were then followed to record any bleeding and thrombotic events. Univariate and multivariate logistic regression analyses were performed to explore associations with bleeding and thrombotic events.

RESULTS

Nineteen of the 162 patients recruited experienced a bleeding event within one year of ROTEM analysis. On univariate analysis, maximum clot firmness (MCF) using both EXTEM and INTEM tests was significantly reduced in patients who had a bleeding event, compared to those who did not (50 mm vs. 57 mm, p < 0.01 and 48 mm vs. 54 mm, p < 0.01, respectively). In addition, on univariate analysis, clotting time (CT) in the INTEM test was prolonged in the bleeding group (214 s vs. 198 s, p = 0.01). On multivariate analysis, only MCFEX was a significant predictor of bleeding events. In contrast, there was no association found between ROTEM parameters and development of thrombosis within a one-year period.

CONCLUSIONS

ROTEM may provide a useful tool in predicting future bleeding events in patients with cirrhosis. Larger studies are required to further validate this finding and explore its application in clinical practice.

Predictors of Non-Variceal Hemorrhage in a National Cohort of Patients With Chronic Liver Disease

Background

Non-variceal hemorrhage in patients with chronic liver disease (CLD) increases morbidity, mortality, and healthcare costs. There are limited data on risk factors for non-variceal hemorrhage in the CLD population. The aim of this study was to assess the predictive value of various clinical and laboratory parameters for non-variceal hemorrhage in CLD patients.

Methods

We conducted a retrospective cohort study of US veterans diagnosed with CLD between 2002 and 2018 within the Veterans Health Administration database. We derived candidate variables from existing risk prediction models for hemorrhage, risk calculators for severity of liver disease, Charlson index of prognostic comorbidities, and prior literature. We used a competing risk analysis to study the relationship between putative risk factors and incidence of non-variceal hemorrhage in patients with CLD.

Results

Of 15,183 CLD patients with no history of cancer or anticoagulation use, 674 experienced non-variceal hemorrhage within 1 year of CLD diagnosis. In multivariable analysis, 11 of the 26 candidate variables independently predicted non-variceal hemorrhage: race, international normalized ratio (INR) > 1.5, bilirubin ≥ 2 mg/dL, albumin ≤ 3.5 g/dL, anemia, alcohol abuse, antiplatelet therapy, chronic kidney disease, dementia, proton pump inhibitor prescription, and recent infection.

Conclusions

In this study of almost 15,000 veterans, risk factors for non-variceal bleeding within the first year after diagnosis of CLD included non-Caucasian race, laboratory parameters indicating severe liver disease and recent infection in addition to the risk factors for bleeding observed in a general non-CLD population.

Anticoagulation for stroke prevention in atrial fibrillation and treatment of venous thromboembolism and portal vein thrombosis in cirrhosis: guidance from the SSC of the ISTH

While advanced liver disease was previously considered to be an acquired bleeding disorder, there is increasing recognition of an associated prothrombotic state with patients being at higher risk of atrial fibrillation (AF) and stroke and venous thromboembolism (VTE) including portal vein thrombosis (PVT). We review the available literature on epidemiology, pathophysiology, and risk factors and provide guidance on anticoagulant management of these conditions in adults with cirrhosis. In patients with Child-Pugh A or B cirrhosis and AF, we recommend anticoagulation with standard-dose direct oral anticoagulants (DOACs) in accordance with cardiology guideline recommendations for patients without liver disease. In those with Child-Pugh C cirrhosis, there is inadequate evidence with respect to the benefit and risk of anticoagulation for stroke prevention in AF. In patients with cirrhosis and acute deep vein thrombosis or pulmonary embolism, we recommend anticoagulation and suggest use of either a DOAC or low-molecular-weight heparin (LMWH)/vitamin K antagonist (VKA) in Child-Pugh A or B cirrhosis and LMWH alone (or as a bridge to VKA in patients with a normal baseline international normalized ratio) in Child-Pugh C cirrhosis. We recommend anticoagulation for patients with cirrhosis and symptomatic PVT. We suggest anticoagulation for those with asymptomatic, progressing PVT and recommend continuing extended anticoagulation for liver transplant candidates with PVT.

Comprehensive investigation of platelet function in patients with cirrhosis

Cirrhosis presents with thrombocytopenia and possibly thrombocytopathy. Previous studies exploring platelet function gave conflicting results and most controversies are explained by the variety of methods employed for investigation. We sought to assess in-vitro the overall platelet function in cirrhosis. We investigated 34 patients by using the following tests. (i)Aggregometry. (ii)Measurement of the content of platelet granules. (iii)Cytometric platelet activation. (iv)Plasmatic markers of in-vivo platelet activation. (v)Platelet procoagulant activity by thrombin generation (TG) in platelet-rich plasma (PRP). TG measured in PRP for patients and controls was similar. Platelets from patients with cirrhosis showed reduction of aggregation and secretion of ATP. Similar results were observed for platelet activation parameters such as P-selectin expression and PAC-1 platelet binding. Plasma levels of βeta-thromboglobulin and soluble P-selectin, were increased in patients-vs-controls. In contrast, there were no patients-vs-controls differences for plasmatic platelet-factor-4. Results are consistent with a state of in-vivo platelet activation and decreased in-vitro aggregation. Since bleeding events following invasive procedures are uncommon in cirrhosis, we speculate that in-vitro aggregometry testing does not reflect the situation occurring in-vivo. Results of the study and pathophysiological considerations support the conclusion that platelet function in cirrhosis as determined by aggregometry, although somewhat impaired, may support the overall hemostatic potential, which is needed for most invasive interventions. These conclusions are in line with the recommendations of international guidelines, warning against indiscriminate use of prophylactic preprocedural administration of platelets before invasive procedures. Decision on platelet support should not be made based on in-vitro laboratory testing for platelet function.

Acquired bleeding disorders

Acquired bleeding disorders can develop in previously healthy people irrespective of age or gender but are particularly common in patients with certain underlying conditions. Here, we review recent advances in the management of acquired haemophilia A (AHA), acquired von Willebrand syndrome (AVWS), and patients with hemostatic abnormalities due to chronic liver disease (CLD). Patients with AHA can now benefit from prophylaxis with emicizumab, a therapeutic antibody that mimics the function of activated coagulation factor VIII. The treatment of AVWS remains challenging in many situations and requires careful consideration of the underlying condition. Haemostatic abnormalities in CLD are often compensated by proportional reduction in pro and anti-haemostatic factors resulting in sustained or even increased thrombin generation. Consequently, bleeding in CLD is rarely caused by haemostatic failure and infusion of plasma or coagulation factor concentrates may not be effective.

Serum/Plasma Proteome in Non-Malignant Liver Disease

The liver is the central metabolic organ and produces 85-90% of the proteins found in plasma. Accordingly, the plasma proteome is an attractive source of liver disease biomarkers that reflects the different cell types present in this organ, as well as the processes such as responses to acute and chronic injury or the formation of an extracellular matrix. In the first part, we summarize the biomarkers routinely used in clinical evaluations and their biological relevance in the different stages of non-malignant liver disease. Later, we describe the current proteomic approaches, including mass spectrometry and affinity-based techniques, that allow a more comprehensive assessment of the liver function but also require complex data processing. The many approaches of analysis and interpretation and their potential caveats are delineated. While these advances hold the promise to transform our understanding of liver diseases and support the development and validation of new liver-related drugs, an interdisciplinary collaboration is needed.

Long-term risk of venous thromboembolism among patients with gastrointestinal non-neoplastic and neoplastic diseases: A prospective cohort study of 484 211 individuals

We conducted a prospective cohort study to examine the associations of 21 gastrointestinal diseases with the risk of incident venous thromboembolism (VTE). The study included 485 936 UK Biobank participants free of baseline VTE. The gastrointestinal diseases were defined by the International Classification of Disease (ICD)-9 and 10 codes with data from the nationwide inpatient data set, the primary care data set, and the cancer registries. Incident VTE cases were defined by ICD-9 and 10 codes with data from the nationwide inpatient data set. Cox proportional hazards regression was used to estimate the associations of baseline gastrointestinal diseases with incident VTE risk. During a median follow-up of 12.0 years, 13 646 incident VTE cases were diagnosed. Eleven gastrointestinal diseases (nine non-neoplastic and two neoplastic) were associated with an increased risk of incident VTE after Bonferroni corrections. The risk of VTE was >50% higher among patients with gallbladder and biliary tract cancer (hazard ratio [HR] 3.15, 95% confidence interval [CI] 95% CI 1.74-5.70), pancreatic cancer (HR 2.84, 95% CI 1.65-4.91), cirrhosis (HR 2.34, 95% CI 1.96-2.79), Crohn's disease (HR 1.61, 95% CI 1.33-1.95), or pancreatitis (HR 1.57, 95% CI 1.31-1.88) compared with individuals without each of these diseases. We observed multiplicative interactions of age, sex, and body mass index with some gastrointestinal diseases (p < .05). A more pronounced, increased risk of VTE was found among younger, female, or obese patients. The study suggests a 50% higher risk of developing VTE among patients with gallbladder and biliary tract cancer, pancreatic cancer, cirrhosis, Crohn's disease, or pancreatitis.

Whole blood thrombin generation shows a significant hypocoagulable state in patients with decompensated cirrhosis

BACKGROUND

Patients with cirrhosis have a normal to increased thrombin generation (TG) capacity in platelet-poor plasma (PPP). By reflecting the contribution of all circulating blood cells, whole blood (WB) TG may allow a more physiological assessment of coagulation.

OBJECTIVES

We compared WB-TG vs PPP-TG in patients with cirrhosis.

METHODS

Assessment of coagulation included routine tests, factor VIII, natural anticoagulants, PPP-TG, and WB-TG. TG assays were performed with and without thrombomodulin. Twenty-five healthy subjects were included as controls.

RESULTS

We included 108 patients (Child-Pugh A/B/C, 44/24/40). Compared with controls, patients had significantly lower platelet count, longer international normalized ratio, higher FVIII, and lower levels of protein C/S and antithrombin. Regarding thrombomodulin-modified TG assays, in compensated cirrhosis, both PPP-TG and WB-TG indicated an increased TG capacity, as reflected by an endogenous thrombin potential (ETP) significantly higher than controls. In contrast, in decompensated cirrhosis, PPP-TG indicated a hypercoagulable state with increased ETP, higher peak height, and shorter time-to-peak than controls, whereas WB-TG revealed a progressive impairment of TG kinetics and total capacity, ultimately resulting in a profound hypocoagulable state in patients with Child-Pugh C cirrhosis (ie, significant prolongation of lag time and time-to-peak with reduction of both ETP and peak height). In decompensated patients, bacterial infections and severity of anemia were associated with a further reduction of both ETP and peak height.

CONCLUSION

Compensated cirrhosis is associated with an increased TG capacity. In decompensated cirrhosis, contrary to PPP-TG, which indicates hypercoagulability, WB-TG shows a significant hypocoagulable state. The clinical value of these findings deserves further investigation.

The Role of the von Willebrand Factor Collagen-Binding Assay (VWF:CB) in the Diagnosis and Treatment of von Willebrand Disease (VWD) and Way Beyond: A Comprehensive 36-Year History

The von Willebrand factor (VWF) collagen binding (VWF:CB) assay was first reported for use in von Willebrand diagnostics in 1986, by Brown and Bosak. Since then, the VWF:CB has continued to be used to help diagnose von Willebrand disease (VWD) (correctly) and also to help assign the correct subtype, as well as to assist in the monitoring of VWD therapy, especially desmopressin (DDAVP). However, it is important to recognize that the specific value of any VWF:CB is predicated on the use of an optimized VWF:CB, and that not all VWF:CB assays are so optimized. There are some good commercial assays available, but there are also some "not-so-good" commercial assays available, and these may continue to give the VWF:CB "a bad reputation." In addition to VWD diagnosis and management, the VWF:CB found purpose in a variety of other applications, from assessing ADAMTS13 activity, to investigation into acquired von Willebrand syndrome (especially as associated with use of mechanical circulatory support or cardiac assist devices), to assessment of VWF activity in disease states in where an excess of high-molecular-weight VWF may accumulate, and lead to increased (micro)thrombosis risk (e.g., coronavirus disease 2019, thrombotic thrombocytopenic purpura). The VWF:CB turns 37 in 2023. This review is a celebration of the utility of the VWF:CB over this nearly 40-year history.

The evolving knowledge on primary hemostasis in patients with cirrhosis: A comprehensive review

Patients with cirrhosis develop complex alterations in primary hemostasis that include both hypocoagulable and hypercoagulable features. This includes thrombocytopenia, multiple alterations of platelet function, and increased plasma levels of von Willebrand factor. Contrary to the historical view that platelet dysfunction in cirrhosis might be responsible for an increased bleeding tendency, the current theory posits a rebalanced hemostasis in patients with cirrhosis. Severe thrombocytopenia is not indicative of the bleeding risk in patients undergoing invasive procedures and does not dictate per se the need for pre-procedural prophylaxis. A more comprehensive and individualized risk assessment should combine hemostatic impairment, the severity of decompensation and systemic inflammation, and the presence of additional factors that may impair platelet function, such as acute kidney injury and bacterial infections. Although there are multiple, complex alterations of platelet function in cirrhosis, their net effect is not yet fully understood. More investigations evaluating the association between alterations of platelet function and bleeding/thrombosis may improve risk stratification in patients with decompensated cirrhosis. Besides hemostasis, the assessment of von Willebrand factor Ag and ADP-induced, whole-blood platelet aggregation normalized by platelet count (VITRO score and PLT ratio) are promising biomarkers to predict the risk of hepatic decompensation and survival in both compensated and decompensated patients. Further investigations into the in vivo interplay between platelets, circulating blood elements, and endothelial cells may help advance our understanding of cirrhotic coagulopathy. Here, we review the complex changes in platelets and primary hemostasis in cirrhosis and their potential clinical implications.

Reappraisal of the conventional hemostasis tests as predictors of perioperative bleeding in the era of rebalanced hemostasis in cirrhosis

New global laboratory procedures mimicking the in vivo hemostasis process led to the changing paradigm of cirrhosis from the prototype of hemorrhagic diseases to a condition in which hemostasis is normal but fragile, thus justifying the hemorrhagic/thrombotic tendencies that affect these patients. The new paradigm was instrumental to change the management of cirrhosis. For example, international guidelines warn against the entrenched practice of testing patients with conventional hemostasis tests and infusing those with abnormalities with fresh-frozen plasma, coagulation factor concentrates, or platelets, prior to surgery/invasive procedures. These recommendations are, however, largely disattended. The practice of testing patients with the prothrombin time or viscoelastometry and using arbitrary cutoffs to make decisions on perioperative prophylaxis is still common and probably driven by medicolegal issues. There is no doubt that prothrombin time and congeners tests are unable to predict bleeding in cirrhosis. However, it cannot be excluded that some tests may be useful in patients who are severely decompensated. Large prospective collaborative studies are warranted. Enrolled patients should be randomized to receive perioperative prophylaxis based on laboratory testing (eg, viscoelastometry, thrombomodulin-modified thrombin generation) or to usual care. However, for these trials to be useful, a third group of patients who do not receive prophylaxis should be included. In conclusion, until results from these studies are available, physicians attending cirrhosis should refrain from using laboratory tests with arbitrary cutoffs to make decision on perioperative prophylaxis. Decision should be made by considering the clinical history of individual patients and the risk of hemorrhage of specific procedures.

Guidelines for the management of coagulation disorders in patients with cirrhosis

Coagulation management in the patient with cirrhosis has undergone a significant transformation since the beginning of this century, with the concept of a rebalancing between procoagulant and anticoagulant factors. The paradigm that patients with cirrhosis have a greater bleeding tendency has changed, as a result of this rebalancing. In addition, it has brought to light the presence of complications related to thrombotic events in this group of patients. These guidelines detail aspects related to pathophysiologic mechanisms that intervene in the maintenance of hemostasis in the patient with cirrhosis, the relevance of portal hypertension, mechanical factors for the development of bleeding, modifications in the hepatic synthesis of coagulation factors, and the changes in the reticuloendothelial system in acute hepatic decompensation and acute-on-chronic liver failure. They address new aspects related to the hemorrhagic complications in patients with cirrhosis, considering the risk for bleeding during diagnostic or therapeutic procedures, as well as the usefulness of different tools for diagnosing coagulation and recommendations on the pharmacologic treatment and blood-product transfusion in the context of hemorrhage. These guidelines also update the knowledge regarding hypercoagulability in the patient with cirrhosis, as well as the efficacy and safety of treatment with the different anticoagulation regimens. Lastly, they provide recommendations on coagulation management in the context of acute-on-chronic liver failure, acute liver decompensation, and specific aspects related to the patient undergoing liver transplantation.

Decreased platelet activation predicts hepatic decompensation and mortality in patients with cirrhosis

BACKGROUND AND AIMS

Patients with cirrhosis show alterations in primary hemostasis, yet prognostic implications of changes in platelet activation remain controversial, and assay validity is often limited by thrombocytopenia. We aimed to study the prognostic role of platelet activation in cirrhosis, focusing on bleeding/thromboembolic events, decompensation, and mortality.

APPROACH AND RESULTS

We prospectively included 107 patients with cirrhosis undergoing a same-day hepatic venous pressure gradient (HVPG) and platelet activation measurement. Platelet activation was assessed using flow cytometry after protease-activated receptor (PAR)-1, PAR-4, or epinephrine stimulation. Over a follow-up of 25.3 (IQR: 15.7-31.2) months, first/further decompensation occurred in 29 patients and 17 died. More pronounced platelet activation was associated with an improved prognosis, even after adjusting for systemic inflammation, HVPG, and disease severity. Specifically, higher PAR-4-inducible platelet activation was independently linked to a lower decompensation risk [adjusted HR per 100 MFI (median fluorescence intensity): 0.95 (95% CI: 0.90-0.99); p =0.036] and higher PAR-1-inducible platelet activation was independently linked to longer survival [adjusted HR per 100 MFI: 0.93 (95% CI: 0.87-0.99); p =0.040]. Thromboembolic events occurred in eight patients (75% nontumoral portal vein thrombosis [PVT]). Higher epinephrine-inducible platelet activation was associated with an increased risk of thrombosis [HR per 10 MFI: 1.07 (95% CI: 1.02-1.12); p =0.007] and PVT [HR per 10 MFI: 1.08 (95% CI: 1.02-1.14); p =0.004]. In contrast, of the 11 major bleedings that occurred, 9 were portal hypertension related, and HVPG thus emerged as the primary risk factor.

CONCLUSIONS

Preserved PAR-1- and PAR-4-inducible platelet activation was linked to a lower risk of decompensation and death. In contrast, higher epinephrine-inducible platelet activation was a risk factor for thromboembolism and PVT.

How to assess hemostasis in patients with severe liver disease

Patients with advanced liver diseases frequently acquire profound alterations in their hemostatic system. Simultaneous changes in procoagulant and anticoagulant systems result in a reset in the hemostatic balance with a relatively neutral net effect, although there are notable hypocoagulable and hypercoagulable features in the hemostatic system in patients with liver disease. Laboratory and clinical studies have demonstrated that patients have a relatively well-preserved hemostatic system even though routine diagnostic tests of hemostasis (prothrombin time, platelet count) suggest a bleeding tendency. Routine diagnostic tests of hemostasis are unsuitable to assess the hemostatic status of patients with liver disease, as these tests are insensitive for the concurrent prohemostatic and antihemostatic changes in these patients. These tests are, however, frequently requested in patients with liver disease, as they are well established indicators of severity of liver disease. This paper will discuss commonly used diagnostic and research-type hemostatic tests and will outline how test results should be interpreted in patients with liver disease.

Platelet Function Decreases with Increasing Severity of Liver Cirrhosis and Portal Hypertension-A Prospective Study

BACKGROUND

 Cirrhotic patients display an increased risk for both bleeding and thrombosis. We investigated platelet activation across Child-Pugh stages (CPSs) and portal hypertension (PH) severity.

MATERIAL AND METHODS

 A total of 110 cirrhotic patients were prospectively included. CPS and hepatic venous pressure gradient (HVPG) were determined. Platelet surface expression of P-selectin and activated glycoprotein (GP) IIb/IIIa were measured by flow cytometry before/after stimulation with protease-activated receptor (PAR)-1 (thrombin receptor activating peptide, TRAP) and PAR-4 (AYPGKF) agonists, epinephrine, and lipopolysaccharide (LPS).

RESULTS

 Platelet count was similar across CPS but lower with increasing PH severity. Expression of P-selectin and activated GPIIb/IIIa in response to TRAP and AYPGKF was significantly reduced in platelets of CPS-B/C versus CPS-A patients (all p < 0.05). Platelet P-selectin expression upon epinephrine and LPS stimulation was reduced in CPS-C patients, while activated GPIIb/IIIa in response to these agonists was lower in CPS-B/C (all p < 0.05). Regarding PH severity, P-selectin and activated GPIIb/IIIa in response to AYPGKF were lower in HVPG ≥20 mmHg patients (both p < 0.001 vs. HVPG < 10 mmHg). Similarly, activated GPIIb/IIIa was lower in HVPG ≥20 mmHg patients after TRAP stimulation (p < 0.01 vs. HVPG < 10 mmHg). The lower platelet surface expression of P-selectin and activated GPIIb/IIIa upon stimulation of thrombin receptors (PAR-1/PAR-4) in CPS-B/C and HVPG ≥20 mmHg patients was paralleled by reduced antithrombin-III levels in those patients (all p < 0.05). Overall, PAR-1- and PAR-4-mediated platelet activation correlated with antithrombin-III levels (p < 0.001).

CONCLUSION

 Platelet responsiveness decreases with increasing severity of liver cirrhosis and PH but is potentially counterbalanced by lower antithrombin-III levels.

Von Willebrand factor processing in patients with advanced chronic liver disease and its relation to portal hypertension and clinical outcome

BACKGROUND AND AIMS

Endothelial dysfunction and portal hypertension (PH) are reflected by increased von Willebrand factor antigen (VWF-Ag) levels in advanced chronic liver disease (ACLD). This study investigated VWF release and cleavage and their association with PH and clinical outcomes.

METHODS

Levels of VWF-Ag, VWF-N (VWF-propeptide), and VWF-A (VWF processed by the main VWF-cleaving protease ADAMTS13) were assessed in 229 patients with clinically stable ACLD (hepatic venous pressure gradient [HVPG] ≥ 6 mmHg; absence of bacterial infections or acute decompensation) undergoing HVPG-measurement. Liver-healthy individuals served as controls (n = 24).

RESULTS

VWF-Ag and VWF-N were similarly accurate for the identification of clinically significant PH (CSPH; HVPG ≥ 10 mmHg) in compensated ACLD (AUROC: VWF-Ag 0.748; VWF-N 0.728). ADAMTS13 activity was similar between patients with ACLD and controls and did not correlate with PH and disease severity, whereas VWF cleavage decreased in patients with CSPH (i.e., VWF-Ag/-A-ratio increased). In vitro VWF activity strongly reflected VWF-Ag levels (Spearman's r = 0.874, p < 0.001), but decreased (vs. controls) in patients with CSPH when normalized to VWF-Ag levels (VWF-activity/-Ag-ratio). VWF-Act/-Ag ratio correlated negatively with ADAMTS13 activity (r =- 0.256, p < 0.001). ADAMTS13 activity was independently predictive for (i) portal vein thrombosis (PVT) and (ii) hepatic decompensation or liver-related death.

CONCLUSIONS

VWF-Ag levels and its propeptide are similarly suitable surrogates of PH in patients with compensated ACLD. ADAMTS13-Act was not linked to disease and PH severity, however, when normalized to VWF-Ag, both VWF cleavage and VWF activity were decreased in patients with CSPH, as compared to liver-healthy individuals. Low ADAMTS13-Act was associated with presumably more procoagulant VWF and adverse outcomes.

CLINICAL TRIAL NUMBER

NCT03267615.

Coagulation management during liver transplantation: monitoring and decision making for hemostatic interventions

PURPOSE OF REVIEW

Rebalanced hemostasis describes the precarious balance of procoagulant and antithrombotic proteins in patients with severe liver failure. This review is aimed to discuss currently available coagulation monitoring tests and pertinent decision-making process for plasma coagulation factor replacements during liver transplantation (LT).

RECENT FINDINGS

Contemporary viscoelastic coagulation monitoring systems have demonstrated advantages over conventional coagulation tests in assessing the patient's coagulation status and tailoring hemostatic interventions. There is increasing interest in the use of prothrombin complex and fibrinogen concentrates, but it remains to be proven if purified factor concentrates are more efficacious and safer than allogeneic hemostatic components. Furthermore, the decision to use antifibrinolytic therapy necessitates careful considerations given the risks of venous thromboembolism in severe liver failure.

SUMMARY

Perioperative hemostatic management and thromboprophylaxis for LT patients is likely to be more precise and patient-specific through a better understanding and monitoring of rebalanced coagulation. Further research is needed to refine the application of these tools and develop more standardized protocols for coagulation management in LT.

Comparison of Postoperative Hemorrhage Risk After Partial Liver Transplantation Versus Whole Liver Transplantation: A Single-Center Experience

BACKGROUND

We aimed to identify risk factors associated with reoperation for postoperative intraperitoneal hemorrhage (PIH) after orthotopic liver transplantation and investigate if partial liver transplantation (PLT) increases the risk of PIH.

METHODS

We retrospectively analyzed the medical records of 304 consecutive recipients who underwent orthotopic liver transplantation at the Affiliated Lihuili Hospital, Ningbo University, from January 2016 to July 2022. Data were compared between recipients who experienced PIH requiring reoperation and those who did not. Subgroup propensity score matching analysis was performed to assess the impact of PLT on PIH risk. Neither prisoners nor participants who were coerced or paid were used in the study.

RESULTS

Among the 304 recipients, 22 (7.2%) underwent reoperation for PIH. Multivariate analysis revealed that the recipient Model for End-Stage Liver Disease (MELD) score (odds ratio = 1.066, 95% CI [1.025-1.109], P = .001) and volume of intraoperative packed red blood cell transfusion (odds ratio = 1.089, 95% CI [1.032-1.481], P = .002) were independent risk factors for PIH. No significant differences were observed in the risk of PIH between PLT and whole liver transplantation.

CONCLUSION

Preoperative MELD score and intraoperative packed red blood cell transfusion should be carefully considered to manage the risk of PIH in liver transplantation recipients. Partial liver transplantation, a crucial approach for addressing donor shortages, does not increase the risk of reoperation for PIH in recipients.

Von Willebrand factor is an independent predictor of short-term mortality in acutely ill patients with cirrhosis

BACKGROUND AND AIMS

Levels of von Willebrand factor (VWF) are elevated in patients with cirrhosis, and correlate well with disease severity. In patients with decompensated cirrhosis (DC), plasma VWF is associated with mortality. The value of VWF in predicting short-term mortality risk in patients with acute-on-chronic liver failure (ACLF) is, however, unclear.

METHODS

We included patients with DC (n = 111) and ACLF (n = 105). We measured VWF levels and correlated these with other laboratory parameters and prediction models for mortality. Also, we assessed the predictive value of VWF in the prediction of 90- and 30-day mortality in patients with DC and ACLF, respectively, and compared this to the predictive value of clinically used prediction models. Finally, we determined the optimal cut-off value for VWF in patients with ACLF.

RESULTS

Sixteen of 111 (14%) patients with DC and 35 of 105 (33%) with ACLF died within 90 and 30 days, respectively. VWF was associated with mortality and correlated closely with other prediction models. In patients with ACLF, VWF levels had a discrimination for 30-day mortality comparable with these models and accurately identified ACLF patients with high 30-day mortality risk.

CONCLUSIONS

Levels of VWF associate closely with risk of mortality in patients with DC and ACLF, and may have predictive utility as a laboratory marker of prognosis. Further research is warranted to assess the additional value of VWF in the prediction of mortality and associated complications in chronic liver failure syndromes.

The prothrombotic tendency of metabolic-associated fatty liver disease

Our understanding of the function of the liver has evolved over the centuries. Early theories proposing that the liver could be used to divine the future have been superseded by our current knowledge of the importance of the liver in processes such as digestion and detoxification. Similarly, although liver disease was previously associated with only an increased risk of bleeding, there is now a substantial body of evidence demonstrating an increased thrombotic potential in patients with this disease. Metabolic-associated fatty liver disease (MAFLD) is increasing in frequency and is likely to overtake alcoholic liver disease as the primary indication for liver transplant in the future. In this review, we discuss the evidence linking liver disease, and MAFLD in particular, with arterial and venous thromboembolic disease. We review the safety and efficacy of anticoagulation in advanced liver disease and consider whether antithrombotic agents could slow or halt the progression of fibrosis in MAFLD.

Von Willebrand Factor as a Biomarker for Liver Disease - An Update

The von Willebrand factor (vWF) is best known for its role in the hemostatic pathway, aiding platelet adhesion and aggregation, as well as circulating along with coagulation factor VIII, prolonging its half-life. However, vWF is more than a hemostatic protein and is a marker of endothelial dysfunction in patients with cirrhosis. The levels of vWF increase progressively as cirrhosis progresses. Despite its qualitative defects, it can support and carry out its hemostatic role and contribute to a pro-coagulant disbalance. Moreover, it has been shown to be a good noninvasive marker for predicting clinically significant portal hypertension (CSPH). The vWF has been shown to predict decompensation and mortality among cirrhosis patients independently of the stage of liver disease and severity of portal hypertension. Increased vWF levels in the setting of endothelial injury predict bacterial translocation and systemic inflammation. The vWF-to-thrombocyte ratio (VITRO) score adds to the diagnostic ability of vWF alone in detecting CSPH non-invasively. Not only have vWF levels been shown to help predict the risk of hepatocellular carcinoma (HCC) among cirrhosis patients, but they also predict the risk of complications post-resection for HCC and response to systemic therapies. vWF-induced portal microthrombi have been purported to contribute to the pathogenesis of acute liver failure progression as well as non-cirrhotic portal hypertension. The prospect of modulation of vWF levels using drugs such as non-selective beta-blockers, statins, anticoagulants, and non-absorbable antibiotics and its use as a predictive biomarker for the response to these drugs needs to be explored.

Interpretable machine learning models for predicting venous thromboembolism in the intensive care unit: an analysis based on data from 207 centers

BACKGROUND

Venous thromboembolism (VTE) is a severe complication in critically ill patients, often resulting in death and long-term disability and is one of the major contributors to the global burden of disease. This study aimed to construct an interpretable machine learning (ML) model for predicting VTE in critically ill patients based on clinical features and laboratory indicators.

METHODS

Data for this study were extracted from the eICU Collaborative Research Database (version 2.0). A stepwise logistic regression model was used to select the predictors that were eventually included in the model. The random forest, extreme gradient boosting (XGBoost) and support vector machine algorithms were used to construct the model using fivefold cross-validation. The area under curve (AUC), accuracy, no information rate, balanced accuracy, kappa, sensitivity, specificity, precision, and F1 score were used to assess the model's performance. In addition, the DALEX package was used to improve the interpretability of the final model.

RESULTS

This study ultimately included 109,044 patients, of which 1647 (1.5%) had VTE during ICU hospitalization. Among the three models, the Random Forest model (AUC: 0.9378; Accuracy: 0.9958; Kappa: 0.8371; Precision: 0.9095; F1 score: 0.8393; Sensitivity: 0.7791; Specificity: 0.9989) performed the best.

CONCLUSION

ML models can be a reliable tool for predicting VTE in critically ill patients. Among all the models we had constructed, the random forest model was the most effective model that helps the user identify patients at high risk of VTE early so that early intervention can be implemented to reduce the burden of VTE on the patients.

The Yin and the Yang of Hemostasis in End-Stage Liver Disease

Patients with end-stage liver disease (ESLD) undergoing liver transplantation (LT) are prone to thromboses both while on the waiting list and in the perioperative period. This hypercoagulability is associated with significant endothelial dysfunction (ED) due to nitric oxide dysregulation. ED and increased thrombin generation are the main factors responsible for this hypercoagulability. Sepsis alone can significantly alter a patient's coagulation profile. In combination with ESLD, however, sepsis or septic shock are responsible for very complex changes. This makes both the assessment and management of coagulation in septic patients with ESLD very challenging. Viscoelastic testing (VET) is the preferred method of coagulation management in patients with cirrhosis because, as with standard laboratory testing, VET can assess the entire coagulation system including the interaction between both pro- and anticoagulants and platelets.

[Use of Thrombopoetin-Receptor-Agonists (TPO-RA) in patients with liver cirrhosis before invasive procedures]

Advanced chronic liver disease is accompanied with relevant changes in the corpuscular and plasmatic coagulation system. Due to thrombocytopenia that is regularly observed in these patients, platelet transfusions are often performed prior invasive procedures to prevent possible bleeding complications. However, platelet transfusions are associated with clinically significant adverse events and economically relevant health care costs. Thus, avoiding unnecessary platelet transfusions remains pivotal in daily clinical practice. The first step is to carefully check if increasing platelet counts prior to a planned invasive procedure is really necessary. Nowadays, two well-tolerated thrombopoetin-receptor agonists (TPO-RAs), Avatrombopaq and Lusutrombopaq, to treat thrombocytopenia preemptively before an invasive procedure in patients with liver cirrhosis are available. This review provides a guide for clinician when to increase platelet counts prior an invasive procedure in patients with liver cirrhosis and helps to identify situations in which the use of TPO-RA may be reasonable.

How I approach bleeding in hospitalized patients

Excessive bleeding is relatively common in adult inpatients, whether as the primary reason for admission or as a development during the hospital stay. Common causes include structural issues, medication effects, and systemic illnesses; occasionally, unexpected bleeding can develop as a result of an undiagnosed or newly acquired bleeding disorder. The first step in caring for the inpatient who is bleeding is to determine whether the bleeding symptom is truly new or whether the patient has a history of abnormal bleeding. Patients with a history of abnormal bleeding may warrant evaluation for inherited bleeding disorders, such as platelet function disorders, von Willebrand disease, hemophilia, or rare factor deficiencies. Patients with no history of bleeding, for whom other causes, such as liver dysfunction, medication effect, disseminated intravascular coagulation, or certain vitamin deficiencies have been ruled out may require evaluation for acquired coagulopathies, such as acquired hemophilia or acquired von Willebrand disease. Here, we present 3 cases to discuss the diagnosis and management of the 2 most common acquired bleeding disorders as well as a patient with a congenital bleeding disorder with a historical diagnosis.

Hemophilia patients: are they naturally anticoagulated?

Hemophilia is an X-linked bleeding disorder, characterized by low plasma levels of coagulation factor VIII (FVIII) (hemophilia A) or FIX (hemophilia B). Because of this, hemophilia patients (HP) were considered as naturally-anticoagulated and therefore protected from thrombosis. Over the last decades hemophilia care underwent striking changes by the introduction of prophylaxis with repeated injections of standard or modified coagulation factor products that maintain steady-state trough levels of the deficient factor. Meanwhile, new medications, not based on replacement therapy, were developed (i.e., emicizumab and others). However, emicizumab (the only licensed drug) can be used only for prophylaxis; during acute bleeding or surgery, HP require additional therapies, supplementing emicizumab with FVIII/IX concentrates or with bypassing agents (e.g., recombinant activated FVII or activated prothrombin complex concentrate). Owing to the new therapeutic strategies, the hemostatic competency of HP is now much better assured than in the past and therefore their life expectancy is considerably improved. Furthermore, the combined effects of the improved life-expectancy and of the steady-state hemostatic competence achieved by prophylaxis, make HP to be near(normal). They are, therefore, liable to be affected by the circumstantial risk factors of venous thromboembolism (VTE) that are common in the general population. Furthermore, HP undergo frequent surgery/invasive procedures (especially major orthopedic surgery) when they are treated with coagulation factor concentrates or bypassing agents that may increase the risk of post-operative VTE. Therefore, one wonders if HP should be considered for perioperative antithrombotic prophylaxis to prevent postoperative VTE.Clinical data on the value of antithrombotic prophylaxis in this setting are scanty. Indeed, data from an observational multicentre prospective study of 46 HP who underwent orthopedic surgery concluded that the prevalence of postoperative symptomatic VTE was similar to that estimated in the general population. Multicenter prospective trials are warranted to address the value of antithrombotic prophylaxis to avoid post-operative VTE in HP, especially during major surgery when regular prophylaxis is supplemented with additional coagulation factor products or bypassing agents. Until this information is available, HP undergoing major surgery whilst on antihemorrhagic prophylaxis supplemented with coagulation factor concentrates or bypassing agents, should at least receive intermittent pneumatic compression.

Viscoelastometry to Manage Bleeding in Liver Disease

A state of "re-balanced haemostasis" describes complex coagulation changes that arise in patients with liver disease. Changes include alterations in procoagulant and anticoagulant proteins, platelets and von Willebrand factor, as well as the fibrinolytic system. Various circumstances including infection, trauma, or surgery may disrupt this balance and predispose an individual to bleeding or thrombosis. The prothrombin time, international normalised ratio, and activated partial thromboplastin time are conventional coagulation screening tests that are routinely employed by clinicians to investigate unexplained bleeding, monitor anticoagulation, and inform preoperative assessments of bleeding risk. These standard coagulation tests assess quantitative defects in procoagulant clotting factors and are insensitive to levels of natural anticoagulants, which together with procoagulant factors, are often perturbed in liver disease. Therefore, the prolongation of clotting times measured by these tests often does not reflect the multifaceted alterations of haemostasis in these patients. Viscoelastic testing (VET) provides a more encompassing assessment of clotting function by recording real-time viscoelastic changes in whole blood and includes parameters that provide information on coagulation factor function, platelet contribution to clot formation, as well as fibrinolysis. To date, VET has been employed to predict and inform transfusion support in obstetric, trauma, and cardiac surgical fields, and its use in patients undergoing liver transplantation is well established. The ability of VET to accurately predict bleeding risk and precisely guide transfusion algorithms for patients with liver disease undergoing other invasive procedures or experiencing bleeding complications has been the topic of research over the last decade. This review is a critical summary of this data and provides a detailed snapshot of the position of VET as a clinical tool in patients with liver disease.

Bleeding and Thrombotic Complications in Patients With Cirrhosis: A State-of-the-Art Appraisal

Much has evolved over the past 25 years regarding our understanding of the coagulopathy of liver disease. Paradoxically, this form of coagulopathy is relatively hypercoagulability despite the common clinical impression of a hemorrhagic tendency. The latter is largely driven by portal-mesenteric venous pressure (ie, portal hypertension) and has little to do with hemostatic pathways. It cannot be emphasized enough that the INR does not offer a meaningful measure in this situation and may lead to interventions such as fresh frozen plasma that can actually worsen portal pressure and hence pressure-driven bleeding. With regard to procedure-related bleeding, we point out substantial differences in the definition of high-risk procedures and propose a new operational definition dependent on the applicability of local hemostatic measures, although this requires further investigation. The common occurrence of venous thrombosis in these patients requires careful consideration of hemostatic pathways and overall risk and benefit of intervention. The decision regarding anticoagulation therapy needs to be driven not only by a global assessment including history of non-portal hypertensive-related bleeding, but also by fall risk which can result in head trauma in patients prone to encephalopathy. This is probably best estimated by frailty but has yet to be adequately investigated. In the background of these concerns, several superimposed and complex conditions including infections and renal dysfunction should be taken into account. Inherited forms of thrombophilia in the setting of cirrhosis perhaps do not outweigh the thrombophilia inherent to liver disease but warrant further consideration.

Daily Aspirin Reduced the Incidence of Hepatocellular Carcinoma and Overall Mortality in Patients with Cirrhosis

BACKGROUND

Cirrhosis is the primary risk factor for hepatocellular carcinoma (HCC) and gastrointestinal bleeding (GI). We aimed to assess the efficacy and safety of daily aspirin on HCC occurrence, overall survival, and GI bleeding in cirrhotic patients.

METHODS

A total of 35,898 eligible cases were enrolled for analyses from an initial 40,603 cirrhotic patients without tumor history. Patients continuously treated with aspirin for at least 84 days were in the therapy group, whereas those without treatment were controls. A 1:2 propensity score matching by age, sex, comorbidities, drugs, and significant clinical laboratory tests with covariate assessment was used.

RESULTS

Multivariable regression analyses revealed that daily aspirin use was independently associated with a reduced risk of HCC (three-year HR 0.57; 95% CI 0.37-0.87; p = 0.0091; five-year HR 0.63, 95% CI 0.45-0.88; p = 0.0072) inversely correlated with the treatment duration [3-12 months: HR 0.88 (95% CI 0.58-1.34); 12-36 months: HR 0.56 (0.31-0.99); and ≥ 36 months: HR 0.37 (0.18-0.76)]. Overall mortality rates were significantly lower among aspirin users compared with untreated controls [three-year HR 0.43 (0.33-0.57); five-year HR 0.51 (0.42-0.63)]. Consistent results were obtained when the laboratory data were included in the propensity score for matching.

CONCLUSIONS

Long-term aspirin use significantly reduced the incidence of HCC and overall mortality without increasing gastrointestinal bleeding in cirrhotic patients.

Portal vein thrombosis in cirrhosis: A literature review

Portal Vein Thrombosis (PVT), a common complication of advanced liver disease, is defined as an obstruction of the portal vein due to thrombus formation that can extend to the superior mesenteric and splenic veins. It was believed that PVT occurred predominantly due to prothrombotic potential. However, recent studies have shown that decreased blood flow related to portal hypertension appears to increase PVT risk as per Virchow's triad. It is well known that there is a higher incidence of PVTs in cirrhosis with a higher MELD and Child Pugh score. The controversy for management of PVTs in cirrhotics lies in the individualized assessment of risks versus benefits of anticoagulation, since these patients have a complex hemostatic profile with both bleeding and procoagulant propensities. In this review, we will systematically compile the etiology, pathophysiology, clinical features, and management of portal vein thrombosis in cirrhosis.

Patient Blood Management in Liver Transplant—A Concise Review

Transfusion of blood products in orthotopic liver transplantation (OLT) significantly increases post-transplant morbidity and mortality and is associated with reduced graft survival. Based on these results, an active effort to prevent and minimize blood transfusion is required. Patient blood management is a revolutionary approach defined as a patient-centered, systematic, evidence-based approach to improve patient outcomes by managing and preserving a patient’s own blood while promoting patient safety and empowerment. This approach is based on three pillars of treatment: (1) detecting and correcting anemia and thrombocytopenia, (2) minimizing iatrogenic blood loss, detecting, and correcting coagulopathy, and (3) harnessing and increasing anemia tolerance. This review emphasizes the importance of the three-pillar nine-field matrix of patient blood management to improve patient outcomes in liver transplant recipients.

The use of prothrombin complex concentrate in chronic liver disease: A review of the literature

Patients with chronic liver disease (CLD) and cirrhosis present a rebalanced hemostatic system in the three phases of haemostasis. This balance is however unstable and can easily tip towards bleeding or thrombosis. Management of both spontaneous bleeding and bleeding during invasive procedures remains a challenge in this patient population. Transfusion of blood products can result in circulatory overload and thereby worsen portal hypertension. As an alternative to fresh frozen plasma (FFP), prothrombin complex concentrates (PCC) may have merit in patients with liver disease because of their low volume. The impact of PCC in in-vitro spiking experiments of cirrhotic plasma is promising, but also warrants cautious use in light of thromboembolic risk. The majority of existing studies carried-out in CLD patients are retrospective or do not have an adequate control arm. A prospective study (the PROTON trial) was set up in 2013 to investigate the utility of PCC in patients undergoing liver transplantation. However, the study has never recruited the planned number of patients. Robust data on PCC safety in CLD is also required. The limited existing evidence does not seem to indicate an excessive thromboembolic risk. Currently, the utilisation of PCC in CLD cannot be routinely recommended but can provide an option for carefully selected cases in which other measures were not sufficient to control bleeding and after delicately weighing risks and benefits.

Viscoelastic Management of Coagulopathy during the Perioperative Period of Liver Transplantation

Viscoelastic testing (VET) in liver transplantation (LT) has been used since its origin, in combination with standard laboratory testing (SLT). There are only a few, small, randomized controlled trials that demonstrated a reduction in transfusion rates using VET to guide coagulation management. Retrospective analyses contrasting VET to SLT have demonstrated mixed results, with a recent concern for overtreatment and the increase in postoperative thrombotic events. An oversight of many studies evaluating VET in LT is a single protocol that does not address the different phases of surgery, in addition to pre- and postoperative management. Furthermore, the coagulation spectrum of patients entering and exiting the operating room is diverse, as these patients can have varying anatomic and physiologic risk factors for thrombosis. A single transfusion strategy for all is short sighted. VET in combination with SLT creates the opportunity for personalized resuscitation in surgery which can address the many challenges in LT where patients are at a paradoxical risk for both life-threatening bleeding and clotting. With emerging data on the role of rebalanced coagulation in cirrhosis and hypercoagulability following LT, there are numerous potential roles in VET management of LT that have been unaddressed.

Oral Anticoagulation in Patients with Chronic Liver Disease

The administration of an anticoagulant in patients with liver disease (nonalcoholic steatohepatitis-NASH, nonalcoholic fatty liver disease-NAFLD, chronic hepatitis, or cirrhosis) who have an indication (atrial fibrillation, venous thrombosis, or pulmonary embolism) is challenging because there is an imbalance between thrombosis and bleeding. There is a need to focus our attention on preventing risk factors because diabetes, obesity, dyslipidemia, smoking, and sedentary behavior are risk factors for both NASH/NAFLD and AF, and these patients require anticoagulant treatment. Patients with advanced liver disease (Child-Pugh C) were excluded from studies, so vitamin K antagonists (VKAs) are still recommended. Currently, VKAs are recommended for other conditions (antiphospholipid syndrome, mitral valve stenosis, and mechanical valve prosthesis). Amongst the patients under chronic anticoagulant treatment, especially for the elderly, bleeding as a result of the improper use of warfarin is one of the important causes of emergency admissions due to adverse reactions. DOACs are considered to be efficient and safe, with apixaban offering superior protection against stroke and a good safety profile as far as major bleeding is concerned compared to warfarin. DOACs are safe in the Child-Pugh A and B classes (except rivaroxaban), and in the Child-Pugh C class are contraindicated. Given that there are certain and reliable data for chronic kidney disease regarding the recommendations, in liver function impairment more randomized studies must be carried out, as the current data are still uncertain. In particular, DOACs have a simple administration, minimal medication interactions, a high safety and effectiveness profile, and now a reversal agent is available (for dabigatran and idarucizumab). Patients are also statistically more compliant and do not require INR monitoring.

Haemostasis in cirrhosis: Understanding destabilising factors during acute decompensation

Hospitalised patients with decompensated cirrhosis are in a rebalanced haemostatic state due to a parallel decline in both pro- and anti-haemostatic pathways. However, this rebalanced haemostatic state is highly susceptible to perturbations and may easily tilt towards hypocoagulability and bleeding. Acute kidney injury, bacterial infections and sepsis, and progression from acute decompensation to acute-on-chronic liver failure are associated with additional alterations of specific haemostatic pathways and a higher risk of bleeding. Unfortunately, there is no single laboratory method that can accurately stratify an individual patient's bleeding risk and guide pre-procedural prophylaxis. A better understanding of haemostatic alterations during acute illness would lead to more rational and individualised management of hospitalised patients with decompensated cirrhosis. This review will outline the latest findings on haemostatic alterations driven by acute kidney injury, bacterial infections/sepsis, and acute-on-chronic liver failure in these difficult-to-treat patients and provide evidence supporting more tailored management of bleeding risk.

Improving Management of Portal Hypertension: The Potential Benefit of Non-Etiological Therapies in Cirrhosis

Portal hypertension is the consequence of cirrhosis and results from increased sinusoidal vascular resistance and hepatic blood inflow. Etiological therapies represent the first intervention to prevent a significant increase in portal pressure due to chronic liver damage. However, other superimposed pathophysiological drivers may worsen liver disease, including inflammation, bacterial translocation, endothelial dysfunction, and hyperactivation of hemostasis. These mechanisms can be targeted by a specific class of drugs already used in clinical practice. Albumin, rifaximin, statins, aspirin, and anticoagulants have been tested in cirrhosis and were a topic of discussion in the last Baveno consensus as non-etiological therapies. Based on the pathogenesis of portal hypertension in cirrhosis, our review summarizes the main mechanisms targeted by these drugs as well as the clinical evidence that considers them a valid complementary option to manage patients with cirrhosis and portal hypertension.

Gut dysbiosis, endotoxemia and clotting activation: A dangerous trio for portal vein thrombosis in cirrhosis

Liver cirrhosis (LC) is associated with portal venous thrombosis (PVT) in roughly 20% of cirrhotic patients but the underlying mechanism is still unclear. Low-grade endotoxemia by lipopolysaccharides (LPS), a component of outer gut microbiota membrane, is detectable in the portal circulation of LC and could predispose to PVT. LPS may translocate into systemic circulation upon microbiota dysbiosis-induced gut barrier dysfunction, that is a prerequisite for enhanced gut permeability and ensuing endotoxemia. Experimental and clinical studies provided evidence that LPS behaves a pro-thrombotic molecule so promoting clotting and platelet activation. Experiments conducted in the portal circulation of cirrhotic patients showed the existence of LPS-related enhanced thrombin generation as well as endothelial dysfunction, venous stasis, and platelet activation. The review will analyze 1) the pro-thrombotic role of endotoxemia in the context of LC 2) the biological plausibility linking endotoxemia with PVT and 3) the potentially interventional tools to lower endotoxemia and eventually hypercoagulation.

Individualized Management of Coagulopathy in Patients with End-Stage Liver Disease

Over the last decades, individualized approaches and a better understanding of coagulopathy complexity in end-stage liver disease (ESLD) patients has evolved. The risk of both thrombosis and bleeding during minimally invasive interventions or surgery is associated with a worse outcome in this patient population. Despite deranged quantitative and qualitative coagulation laboratory parameters, prophylactic coagulation management is unnecessary for patients who do not bleed. Transfusion of red blood cells (RBCs) and blood products carries independent risks for morbidity and mortality, including modulation of the immune system with increased risk for nosocomial infections. Optimal coagulation management in these complex patients should be based on the analysis of standard coagulation tests (SCTs) and viscoelastic tests (VETs). VETs represent an individualized approach to patients and can provide information about coagulation dynamics in a concise period of time. This narrative review will deliver the pathophysiology of deranged hemostasis in ESLD, explore the difficulties of evaluating the coagulopathies in liver disease patients, and examine the use of VET assays and management of coagulopathy using coagulation factors. Methods: A selective literature search with PubMed as the central database was performed with the following.

Thrombocytopenia and liver disease: pathophysiology and periprocedural management

Abnormal bleeding in patients with liver disease may result from elevated portal pressure and varix formation, reduced hepatic synthesis of coagulation proteins, qualitative platelet dysfunction, and/or thrombocytopenia. Major mechanisms of thrombocytopenia in liver disease include splenic sequestration and impaired platelet production due to reduced thrombopoietin production. Alcohol and certain viruses may induce marrow suppression. Immune thrombocytopenia (ITP) may co-occur in patients with liver disease, particularly those with autoimmune liver disease or chronic hepatitis C. Drugs used for the treatment of liver disease or its complications, such as interferon, immunosuppressants, and antibiotics, may cause thrombocytopenia. Periprocedural management of thrombocytopenia of liver disease depends on both individual patient characteristics and the bleeding risk of the procedure. Patients with a platelet count higher than or equal to 50 000/µL and those requiring low-risk procedures rarely require platelet-directed therapy. For those with a platelet count below 50 000/µL who require a high-risk procedure, platelet-directed therapy should be considered, especially if the patient has other risk factors for bleeding, such as abnormal bleeding with past hemostatic challenges. We often target a platelet count higher than or equal to 50 000/µL in such patients. If the procedure is elective, we prefer treatment with a thrombopoietin receptor agonist; if it is urgent, we use platelet transfusion. In high-risk patients who have an inadequate response to or are otherwise unable to receive these therapies, other strategies may be considered, such as a trial of empiric ITP therapy, spleen-directed therapy, or transjugular intrahepatic portosystemic shunt placement.

Incident portal vein thrombosis in liver transplant recipients in New Zealand: Predictors of risk and validation of portal vein thrombosis risk index calculator

The risk of spontaneous portal vein thrombosis (PVT) is increased in patients on the waiting list for liver transplantation and increases perioperative risks. A predictive PVT risk-index (PVT-RI) calculator has been proposed to determine the risk of incident PVT. We performed a retrospective analysis on adult liver transplant recipients at the NZ Liver Transplant Unit between January 1998 and February 2020. Variables reviewed included age at listing and transplantation, wait time from listing to transplant, indication for listing, gender, ethnicity, etiology of liver disease, listing MELD score, hepatocellular carcinoma (HCC), moderate-to-severe ascites, hepatic encephalopathy (>grade 2), transjugular intrahepatic portosystemic shunt (TIPSS), spontaneous bacterial peritonitis (SBP), and diabetes. Incident PVT was determined by imaging of patients while on the waiting list and assessment at transplantation. A total of 553 out of 706 patients met the inclusion criteria. Of those 553, 18 (3.3%) patients had incident PVT. The PVT-RI calculator was not validated in our cohort with only one of those 18 (6%) patients having a score of >4.6 (high risk cut-off score). Longer waiting time for transplant and listing for liver failure rather than HCC were independent predictors of the risk of incident PVT. There was no statistically significant difference in the incidence of PVT in viral vs. non-viral and cholestatic vs. non-cholestatic etiology of chronic liver disease. Patients with longer waiting times on the transplant waiting list should be monitored regularly for PVT.

Rational hemostatic management in cirrhosis: from old paradigms to new clinical challenges

INTRODUCTION

Patients with cirrhosis are at risk of both thrombotic and hemorrhagic events. Traditional hemostatic tests are inadequate to assess the complex and fragile balance of hemostasis in this setting, especially in advanced stages of disease such as decompensated cirrhosis or acute on chronic liver failure (ACLF). Furthermore, the indiscriminate use of pro-hemostatic agents for prophylaxis and treatment of bleeding episodes is still debated and often contraindicated. Alongside, splanchnic, and peripheral thrombotic events are frequent in this population and require management that involves a careful balance between risks and benefits of antithrombotic therapy.

AREAS COVERED

This review aims to address the state of the art on the clinical management of the hemostatic balance of cirrhosis in terms of established knowledge and future challenges.

EXPERT OPINION

The old paradigm of cirrhosis as a naturally anticoagulated condition has been challenged by more sophisticated global tests of hemostasis. Integrating this information in the clinical decision-making is still challenging for physicians and experts in hemostasis.

ADAMTS-13/von Willebrand factor ratio: A prognostic biomarker for portal vein thrombosis in compensated cirrhosis. A prospective observational study

BACKGROUND AND AIMS

In cirrhosis, decreased portal flow velocity, thrombophilia factors, and portal hypertension are considered risk factors for portal vein thrombosis (PVT). In cirrhosis, the transformation of the stellate cells causes a progressive decrease of ADAMTS-13, while VWF multimers secretion by endothelial cells is strongly enhanced. This imbalance leads to an accumulation of ultra-large VWF multimers that in sinusoidal circulation could favor PVT both in intra- and extra-hepatic branches, mostly in decompensated cirrhosis. This prospective study was aimed at identifying possible clinical, biochemical, and hemostatic factors predictive for non-tumoral PVT in a cohort of patients with compensated cirrhosis.

METHODS

Seventynine compensated cirrhosis patients were prospectively followed for 48 months, receiving a periodic Doppler-ultrasound liver examination associated with an extensive evaluation of clinical, biochemical, and hemostatic profile.

RESULTS

Five patients developed PVT (cumulative prevalence = 6.3%), occurring 4-36 months after enrollment. In logistic regression analysis, the ADAMTS-13/VWF:GpIbR ratio < 0.4 was the only independent variable significantly associated with PVT (OR 14.6, 95% C.I.:1.36-157.2, p = 0.027). A Cox-regression-analysis confirmed this finding (HR = 7.7, p = 0.027).

CONCLUSIONS

The ADAMTS-13/VWF ratio < 0.4 measured in compensated cirrhosis could be a reliable predictive biomarker for PVT development, paving the way to novel therapeutic strategies to prevent and treat PVT in this clinical setting.

A brief history of liver transplantation and transplant anesthesia

In this review, we describe the major milestones in the development of organ transplantation with a specific focus on hepatic transplantation. For many years, the barriers preventing successful organ transplantation in humans seemed insurmountable. Although advances in surgical technique provided the technical ability to perform organ transplantation, limited understanding of immunology prevented successful organ transplantation. The breakthrough to success was the result of several significant discoveries between 1950 and 1980 involving improved surgical techniques, the development of effective preservative solutions, and the suppression of cellular immunity to prevent graft rejection. After that, technical innovations and laboratory and clinical research developed rapidly. However, these advances alone could not have led to improved transplant outcomes without parallel advances in anesthesia and critical care. With increasing organ demand, it proved necessary to expand the donor pool, which has been achieved with the use of living donors, split grafts, extended criteria organs, and organs obtained through donation after cardiac death. Given this increased access to organs and organ resources, the number of transplantations performed every year has increased dramatically. New regulatory organizations and transplant societies provide critical oversight to ensure equitable organ distribution and a high standard of care and also perform outcome analyses. Establishing dedicated transplant anesthesia teams results in improved organ transplantation outcomes and provides a foundation for developing new standards for other subspecialties in anesthesiology, critical care, and medicine overall. Through a century of discovery, the success we enjoy at the present time is the result of the work of well-organized multidisciplinary teams following standardized protocols and thereby saving thousands of lives worldwide each year. With continuing innovation, the future is bright.

Preprocedural prophylaxis with blood products in patients with cirrhosis: Results from a survey of the Italian Association for the Study of the Liver (AISF)

INTRODUCTION

The concept of rebalanced hemostasis in cirrhosis challenges the policy of transfusing plasma or platelets before invasive procedures in patients with prolonged PT or severe thrombocytopenia. Recent guidelines recommend against plasma transfusion and suggest avoiding/minimizing platelet transfusions.

AIM

We assessed how hepato-gastroenterologists manage prolonged PT/INR or severe thrombocytopenia before invasive procedures.

METHODS

On May 2021, AISF members were sent a questionnaire addressing the PT/INR and platelet thresholds required before invasive procedures, the use of other markers of bleeding risk or other hemostatic treatments and the burden of pre-emptive plasma and platelet transfusions.

RESULTS

Of 62 respondents, 94% and 100% use PT/INR and platelet count to assess bleeding risk, respectively. Only 37% and 32% require less conservative PT/INR or platelet counts thresholds for low-risk procedures, respectively. As for those applying single thresholds, 68% require PT/INR <1,5 and 86% require platelet counts ≥50 × 10⁹/L. Half respondents use additional indicators of bleeding risk and 63% other hemostatic treatments. Low-risk procedures account for 70% of procedures, and for 50% and 59% of plasma and platelets units transfused, respectively.

CONCLUSIONS

the survey indicates lack of compliance with guidelines that advise against plasma and platelet transfusions before invasive procedures and the need for prospective studies and inter-society consensus workshops.

Blood products and liver transplantation: A strategy to balance optimal preparation with effective blood stewardship

BACKGROUND

Unanticipated transfusion requirements during liver transplantation can delay lifesaving intraoperative resuscitation and strain blood bank resources. Risk-stratified preoperative blood preparation can mitigate these deleterious outcomes.

STUDY DESIGN AND METHODS

A two-tiered blood preparation protocol for liver transplantation was retrospectively evaluated. Eleven binary variables served as criteria for high-risk (HR) allocation. Primary outcomes included red blood cell (RBC), plasma (FFP), and platelet (Plt) utilization. Secondary outcomes included product under- and overpreparation. Contingency tables for transfusion requirements above the population means were generated using 15 clinical variables. Modified protocols were developed and retrospectively optimized using the study population.

RESULTS

Of 225 recipients, 102 received HR preoperative orders, which correlated to higher intraoperative transfusion requirements. However, univariate analysis identified only two statistical risk factors per product: Hgb ≤7.8 g/dl (p < .001) and MELD ≥38 (p = .035) for RBCs, Hgb ≤7.8 g/dl (p = .002) and acute alcoholic hepatitis (p = 0.015) for FFP, and Hgb ≤7.8 g/dl (p = .001) and normothermic liver preservation (p = .037) for Plts. Based on these findings, we developed modified protocols for individual products, which were evaluated retrospectively for their effectiveness at reducing under-preparatory events while limiting product overpreparation. Cohort statistics were used to define the preparation strategy for each protocol. Retrospective comparative analysis demonstrated the superiority of the modified protocols by improving the under-preparation rate from 24% to <10% for each product, which required a 1.56-fold and 1.44-fold increase in RBC and FFP overpreparation, respectively. Importantly, there was no difference in Plt overpreparation.

DISCUSSION

We report translatable data-driven blood bank preparation protocols for liver transplantation.