Reply to "Peripheral versus central venous blood sampling does not influence the assessment of platelet activation in cirrhosis"

Activation of the Contact System and Intrinsic Pathway in Peripheral and Portal Venous Circulations in Liver Cirrhosis

BACKGROUND

 Portal vein system-specific risk factors contributing to portal vein thrombosis in cirrhosis are poorly investigated.

AIM

 This study aimed to quantify contact system and intrinsic pathway activation in the peripheral compared to portal venous blood in patients with decompensated cirrhosis.

METHODS

 Adult patients with cirrhosis undergoing transjugular intrahepatic portosystemic shunt underwent simultaneous blood sampling from a peripheral vein and the portal vein. Complexes of serine proteases with their respective inhibitors were measured by ELISA to quantify contact system (PKa:C1-INH [plasma kallikrein:C1-esterase inhibitor] and FXIIa:C1-INH) and intrinsic pathway activation (FXIa:C1-INH, FXIa:α1at [α-1 antitrypsin], FXIa:AT [antithrombin], and FIXa:AT).

RESULTS

 Twenty patients with cirrhosis (mean age 55 ± 7 years, M = 58%, Child-Pugh A/B/C 6/11/3) and 25 healthy controls (mean age 45 ± 12 years, M = 60%) were enrolled. The etiology of cirrhosis was primarily alcohol abuse, followed by chronic viral infection. Log-transformed peripheral levels of all the complexes were significantly higher in patients compared with controls. While levels of PKa:C1-INH, FXIIa:C1-INH, FXIa:C1-INH and FXIa:α1at were similar in peripheral and portal venous blood in cirrhotic patients, FXIa:AT and FIXa:AT levels were significantly higher in portal blood (p = 0.013 and 0.011, respectively). FXIa:C1-INH significantly correlated with both contact system complexes (FXIIa:C1-INH and PKa:C1-INH) and with FIX:AT.

CONCLUSION

 Markers of contact system and intrinsic pathway activation in the systemic circulation were significantly higher in cirrhosis versus controls. Complexes of FXIa and FIXa with AT were significantly higher in the portal than in peripheral plasma in cirrhosis, possibly indicating a unique heparin-like effect in portal venous blood.

Coagulation factor XI in cirrhosis does not predict thrombo-hemorrhagic complications and hepatic decompensation

INTRODUCTION

Factor XI (FXI) is associated with thrombosis in patients without liver disease, but it alterations and prognostic value in cirrhosis are uncertain.

PATIENTS AND METHODS

We studied a prospective cohort of cirrhosis patients determining FXI and its association with portal vein thrombosis (PVT), bleeding, and hepatic decompensation/ACLF during 1-year follow-up. Odds ratios (OR) and 95 % CIs were calculated using logistic regression.

RESULTS

We included 183 patients (Child-Pugh [CP] A/B/C 57/59/57). FXI was reduced in cirrhosis, decreasing with CP stage (78 % [66-94] vs. 58 % [44-78] vs. 41 % [30-52] in CP A, B, and C, respectively; p < 0.001). FXI was correlated with MELD score (rho: -0.6, p < 0.001), INR (rho: -0.6, p < 0.001), and platelet count (rho: 0.4, p < 0.001). Sixteen patients (8.7 %) experienced PVT, which only predictor was baseline platelet count (OR: 0.94; CI95 %: 0.91-0.97, p < 0.001). Bleeding occurred in 7 patients (3.8 %). Cirrhosis severity, platelet count, fibrinogen, and FXI (60% vs. 78 %; p = 0.2) were comparable between bleeding and non-bleeding individuals. Finally, no association was found between FXI and hepatic decompensation/ACLF, which were predicted by lower albumin and platelet count, respectively.

CONCLUSION

FXI seems not to be responsible for thrombosis and cirrhosis progression. The lack of association between low FXI and bleeding events, however, indirectly opens to future studies evaluating FXI inhibitors in cirrhosis.

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.

Decreased Platelet Aggregation in Patients with Decompensated Liver Cirrhosis and TIPS Implantation

Transjugular intrahepatic portosystemic shunt (TIPS) implantation is an effective treatment of portal hypertension in patients with decompensated liver cirrhosis. However, some patients develop TIPS thrombosis with recurrence of portal hypertension. The role of platelets in TIPS thrombosis and the necessity of antiplatelet therapy is unclear. Therefore, we aimed to study platelet function in patients with liver cirrhosis prior to and after TIPS implantation. Platelet aggregation was tested in peripheral and portal-vein blood patient samples on the day (D) of TIPS implantation (D0), D4 and D30 following the procedure (platelet count above 100 × 103/µL, aspirin starting on D5) using whole-blood impedance aggregometry (WBIA) and light transmission aggregometry (LTA). In addition, surface platelet activation markers (P-selectin, activated GPIIb/IIIa) and platelet-neutrophil complexes (PNCs) were assessed by flow cytometry. Thrombin receptor activating peptide 6 (TRAP-6), adenosine diphosphate (ADP) and arachidonic acid (AA) were used as agonists. Healthy subjects were included as controls. Agonist-induced platelet aggregation was reduced (WBIA: TRAP-6 p < 0.01, ADP p < 0.01, AA p < 0.001; LTA: TRAP-6 p = 0.13, ADP p = 0.05, AA p < 0.01) in patients (D0, n = 13) compared with healthy subjects (n = 9). While surface activation markers at baseline were negligibly low, the percentage of PNCs was higher in patients than in controls (p < 0.05). ADP-induced P-selectin expression was increased (p < 0.001), whereas TRAP-6-induced GPIIb/IIIa activation was impaired (p < 0.001) in patients versus controls. PNC formation in response to agonists was not different between groups. Results did not differ between peripheral and portal-vein blood of patients (D0, n = 11) and did not change over time (D0, D4, D30) following TIPS implantation (n = 9). In summary, patients with decompensated liver cirrhosis display in vitro platelet aggregation defects in response to various agonists. Defective aggregation persists upon TIPS implantation. Therefore, we conclude that antiplatelet treatment to prevent TIPS thrombosis is questionable.

Elevated levels of soluble glycoprotein V - The plasma marker of platelet activation by thrombin in patients with early stage primary biliary cholangitis (PBC)

PURPOSE

There is a growing body of evidence for a prothrombotic tendency in patients with primary biliary cholangitis (PBC). The aim of the study was to evaluate coagulation disorders in patients with early stage PBC compared to healthy controls and evaluation of their relationship with clinical data, with particular emphasis on minimal hepatic encephalopathy (MHE).

PATIENTS AND METHODS

Fifty-one participants (PBC group - 38 patients, all patients but one Child-Pugh A; control group - 13 healthy controls) were included in our prospective, single center study. We assessed the plasma levels of sGPV, plasma procoagulant phospholipids (PPL) and rotational thromboelastometry (ROTEM) profiles in all study participants. Porto-systemic encephalopathy syndrome test was used to assess MHE.

RESULTS

The sGPV levels were higher in the PBC group compared to the controls: 36.07 ​± ​11.32 ​ng/mL vs 27.04 ​± ​11.72 ​ng/mL, p ​= ​0.031. The PPL level was lower in the PBC group compared to controls resulting in increased clotting time in a factor Xa-based coagulation assay: 54.65 (47.83-58.83) sec. vs 45.90 (43.3-50.5) sec., p ​= ​0.0065. PPL levels were correlated with platelet count (rho ​= ​-0.46, p ​= ​0.001). ROTEM parameters did not differ significantly between groups. Coagulation parameters did not differ significantly between patients with and without MHE.

CONCLUSIONS

We have showed increased levels of sGPV - a plasma marker of platelet activation by thrombin in patients with early stage PBC compared to healthy controls. We found no relationship between the coagulation disorders and the occurrence of MHE. The PPL level was lower in the PBC group.

Increased platelet ratio in patients with decompensated cirrhosis indicates a higher risk of portal vein thrombosis

Patients with decompensated cirrhosis are at risk of portal vein thrombosis (PVT). We prospectively investigated whether alterations of platelet aggregation can predict PVT in decompensated cirrhosis. At baseline, all patients underwent whole-blood aggregometry (Multiplate®) to assess ADP-induced platelet aggregation. Aggregometry results were expressed as the ratio between platelet aggregation and platelet count (PLT ratio). Then, patients with cirrhosis were prospectively followed for 1 year for PVT development. One-hundred and twenty-eight patients with decompensated cirrhosis were included (Child-Pugh A/B/C 12/39/49%). The cumulative incidence of PVT was 14%. On multivariate analysis, the PLT ratio (OR 4.5, 95% CI 2.63-7.67; p < .0001) and Child-Pugh C versus A/B (OR 4.1, 95% CI 1.18-14.80; p = .03) were independently associated with PVT. The discriminative ability of the PLT ratio was higher than Child-Pugh (AUC 0.92 vs 0.70, p < .0001). A PLT ratio > 0.75 had 83% sensitivity and 84% specificity for PVT. In conclusion, the PLT ratio by Multiplate® seems a promising thrombotic biomarker in decompensated cirrhosis.

Portal Vein Thrombosis in the Setting of Cirrhosis: A Comprehensive Review

Portal vein thrombosis constitutes the most common thrombotic event in patients with cirrhosis, with increased rates in the setting of advanced liver disease. Despite being a well-known complication of cirrhosis, the contribution of portal vein thrombosis to hepatic decompensation and overall mortality is still a matter of debate. The incorporation of direct oral anticoagulants and new radiological techniques for portal vein recanalization have expanded our therapeutic arsenal. However, the lack of large prospective observational studies and randomized trials explain the heterogenous diagnostic and therapeutic recommendations of current guidelines. This article seeks to make a comprehensive review of the pathophysiology, clinical features, diagnosis, and treatment of portal vein thrombosis in patients with cirrhosis.