Abstract Number: PB0553
Meeting: ISTH 2021 Congress
Background: Bleeding severity in hemophilic patients, reflecting low levels of thrombin generation (TG), can vary widely between patients with the same coagulation factor deficiency level, possibly reflecting differences in tissue factor pathway inhibitor (TFPI).
Aims: To compare TFPI levels in patients with severe hemophilia A (HA) and severe hemophilia B (HB) and to investigate the relationships between TG potential and bleeding, between TG potential and TFPI level and between TFPI level and bleeding.
Methods: Data on bleeding episodes recorded during follow-up visits over 5-10 years were collected and used to calculate annualized hemarthrosis rate (AHR) and annualized bleeding rate (ABR). Free TFPI levels (Asserachrom Free TFPI, Stago) and basal TG parameters were determined in platelet-poor plasma (PPP) and platelet-rich plasma (PRP) using the CAT system.
Results: Mean TFPI levels did not differ significantly between HA (n = 34) and HB (n = 19). Mean values in PPP of endogenous thrombin potential (ETP) and thrombin peak (Peak) were higher at TFPI levels < 9.4 ng/mL than at TFPI levels > 14.3 ng/mL (ETP = 287.4 ± 11.1 vs 142.6 ± 69.1 nmol; p = 0.002) (Peak = 12.4 ± 5.6 vs 5.1 ± 2.6 nmol; p = 0.001) respectively. In patients on demand treatment, a statistically significant inverse relationship between ETP in PRP was only seen with AHR. In patients on prophylaxis no association was found between basal TG parameters neither with ABR nor AHR. An association was observed between AHR or ABR and TFPI levels, only in patients on prophylaxis.
Conclusions: Bleeding tendency depends on the basal TG only in patients without prophylactic treatment.
Moreover, TFPI levels influences the bleeding tendency for patients receiving a prophylactic treatment only. In other words, the difference of bleeding tendency in severe hemophilia patients on prophylaxis can be explain by different TFPI levels.
To cite this abstract in AMA style:Tardy-Poncet B, Montmartin A, Genre-Volot F, Chambost H, De Maistre E, Morange P, Ardillon L, Dargaud Y, Lienhart A, Nguyen P, Frotscher B, Wibaut B, Derory C, Delolme M, Tardy B. Tissue Factor Pathway Inhibitor (TFPI) Levels and Bleeding Risk in Patients with Severe Hemophilia A or B [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/tissue-factor-pathway-inhibitor-tfpi-levels-and-bleeding-risk-in-patients-with-severe-hemophilia-a-or-b/. Accessed November 29, 2023.
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