Extended Half-Life Recombinant Factor VIII Conjugated with Modifying Substances Does Not Affect Fibrin Clot Formation or Stability in Haemophilia A Blood Samples.

Factor V is an anticoagulant of the extrinsic pathway of coagulation and modifier of thrombin generation in hemophilia A.

FV is an endogenous anticoagulant that inhibits TF-initiated coagulation by limiting FX activation by TF:FVIIa through a membrane-dependent mechanism, which refines models of coagulation initiation and may help explain how FV variation contributes to bleeding and thrombosis.

Tissue Factor/Factor XIa Dual-activated Thrombin Generation is Able to Reliably Measure Thrombin Generation at All Hemophilia A Disease Severities

The standardized TF/FXIa dual-activated TGA represents a tool for assessing individual coagulation potential in hemophilia A and showed substantial variation in interindividual TG levels among patients with comparable FVIII activity levels.

Activated Platelets Protect Factor VIIIa from Degradation by Activated Protein C and from Subunit Dissociation.

Data indicate that platelets support greater activity of FVIII than PLV through stabilization against dissociation of the A2 domain and protection from degradation by APC.

Perioperative von Willebrand Factor and Factor VIII Kinetics in von Willebrand Disease Patients Treated With Different Clotting Factor Concentrates.

INTRODUCTION Patients with von Willebrand disease (VWD) undergoing surgery require von Willebrand factor (VWF) and factor VIII (FVIII) supplementation for adequate haemostasis. Plasma-derived clotting factor concentrates differ in their VWF:FVIII activity ratios: high-ratio product (HRP, 10:1), intermediate-ratio product (IRP, 2.4:1), and low-ratio product (LRP, 1:1). These differences may affect FVIII kinetics. METHODS This single-centre observational study included VWD patients undergoing surgery, treated with an HRP, IRP, or LRP, and with ≥2 perioperative VWF or FVIII measurements between 2009 and 2024. VWF and FVIII trajectories were assessed using linear mixed-effects models. Secondary endpoints were bleeding and venous thromboembolic events (VTE). RESULTS In total, 123 patients were included; 63% underwent major surgery. Twenty-four patients received HRP, 61 received IRP and 38 received LRP. The median number of infusions was three across groups. Incremental VWF recoveries were 1.7 IU/dL per IU/kg for HRP, 1.3 for IRP, and 2.4 for LRP. FVIII recoveries were 2.5 for IRP and 2.7 for LRP. Over time, HRP showed higher mean VWF levels than IRP (Δ26 IU/dL; p = 0.010). HRP was associated with higher FVIII levels compared with IRP (Δ48 IU/dL; p < 0.001) and LRP (Δ35 IU/dL; p = 0.021). No difference was found between IRP and LRP. In patients receiving three consecutive infusions in 24 h, FVIII levels remained higher with HRP than IRP (Δ38 IU/dL; p = 0.019). No VTEs occurred. CONCLUSION IRP and LRP led to greater initial VWF and FVIII peaks, whilst HRP produced more sustained FVIII elevation. Recognising these kinetic differences may guide tailored perioperative management of patients with VWD.

Thrombosis and Haemostasis Clinical Validation of a Point-of-Care Whole Blood Coagulometer in Patients on Factor Xa Inhibitors

Hemostatic Profiling of Generic Factor Xa Inhibitors Using ROTEM® Viscoelastometry and Multimodal Coagulation Assays: A Real-World Study in a Tunisian Cohort

Background The emergence of generic direct factor Xa inhibitors like apixaban and rivaroxaban has significantly increased the global availability of essential anticoagulants in developing nations. However, we still lack a detailed understanding of how these generic versions behave in real-world clinical practice. This research offers an initial multimodal evaluation, within a Tunisian population, integrating conventional coagulation tests with specific anti-Xa activity and rotational thromboelastometry. Methods We conducted a prospective cross-sectional study at Sahloul University Hospital (Sousse, Tunisia) including 33 patients (mean age 71.3 ± 11.7 years) receiving generic apixaban (n = 25) or rivaroxaban (n = 8) for ≥1 month. Sixty-six paired blood samples were collected at trough (30 min before the next dose) and peak (2–3 h after intake). Standard coagulation tests (PT, aPTT, fibrinogen), calibrated chromogenic anti-Xa activity, and ROTEM®sigma assays were performed. Results Rivaroxaban produced consistent PT prolongation at trough (87.5%) and peak (100%), while apixaban exerted a milder, concentration-dependent effect (45.5% at trough; 73.9% at peak). PT correlated inversely with anti-Xa activity for both agents (apixaban: r = −0.79 at peak; rivaroxaban: r = −0.84 at peak). aPTT and fibrinogen were not significantly affected. Among ROTEM parameters, EXTEM clotting time (CT) was the sole viscoelastic parameter significantly correlated with anti-Xa activity: rivaroxaban r = 0.88 (p = 0.004) at trough and r = 0.87 (p = 0.012) at peak; apixaban ρ = 0.54 (p = 0.021) at trough and ρ = 0.69 (p < 0.001) at peak. INTEM CT showed no significant correlation for either agent. Clot firmness, formation time, and maximum lysis were unaffected by either agent. Conclusion Generic factor Xa inhibitors show hemostatic profiles mirroring those of brand-name versions. EXTEM CT emerged as the ROTEM® parameter most closely tied to anticoagulant intensity, making it a practical bedside surrogate in urgent settings.