In patients with hemophilia, a decreased thrombin generation profile is associated with a severe bleeding phenotype

Abstract

Background: Heterogeneity in clinical bleeding phenotype has been observed in hemophilia patients with similar FVIII or FIX activity levels. Thrombin generation and plasmin generation, as a global hemostasis assay, may contribute to a better prediction of which patients are at an increased risk of bleeding.

Objectives: The objective of this study was to describe the association between clinical bleeding phenotype and thrombin generation and plasmin generation profiles in patients with hemophilia.

Methods: The Nijmegen Hemostasis Assay, which simultaneously measures thrombin and plasmin generation, was performed in plasma samples of patients with hemophilia participating in the sixth Hemophilia in the Netherlands study (HiN6). Patients receiving prophylaxis underwent a washout period. A severe clinical bleeding phenotype was defined as a self-reported annual bleeding rate of ≥5, a self-reported annual joint bleeding rate of ≥3, or the use of secondary/tertiary prophylaxis.

Results: In total, 446 patients, with a median age of 44 years, were included in this substudy. Thrombin generation and plasmin generation parameters differed between patients with hemophilia and healthy individuals. The median thrombin peak height was 1.0 nM, 25.9 nM, 47.1 nM, and 143.9 nM in patients with severe, moderate, and mild hemophilia and healthy individuals, respectively. A severe bleeding phenotype was observed in patients with a thrombin peak height of <49% and a thrombin potential of <72% compared to healthy individuals, and was independent of the hemophilia severity. The median thrombin peak height was 0.70% in patients with a severe clinical bleeding phenotype and 30.3% in patients with a mild clinical bleeding phenotype. The median thrombin potentials for these patients were 0.06% and 59.3%, respectively.

Conclusion: A decreased thrombin generation profile is associated with a severe clinical bleeding phenotype in patients with hemophilia. Thrombin generation in combination with bleeding severity may be a better tool to personalize prophylactic replacement therapy irrespective of hemophilia severity.

Keywords: factor VIII; hemophilia A; hemophilia B; phenotype; thrombin.

Figure 1

Flow diagram of patients included in the study.

Figure 2

Thrombin and plasmin generation parameters at baseline in patients with hemophilia compared to healthy individuals. Parameters given are lag time (A), time to thrombin peak (B), thrombin peak height (C), thrombin potential (D), plasmin peak height (E), and plasmin potential (F). Lines represent median with interquartile range in all graphs. ∗∗P < .01; ∗∗∗∗P < .0001.

Figure 3

Association between annual bleeding rate and thrombin peak height in adult patients with hemophilia. (A) Annual bleeding rate according to thrombin peak height in all patients included with on-demand treatment (n = 318). This group includes patients with mild (n = 228), moderate (n = 69), and severe hemophilia (n = 21). (B) Annual bleeding rate according to thrombin peak height in patients with mild hemophilia treated on demand. (C) Annual bleeding rate according to thrombin peak height in patients with moderate hemophilia treated on demand. (D) Annual bleeding rate according to thrombin peak height in patients with severe hemophilia treated on demand. (E) Thrombin peak height in patients receiving secondary/tertiary prophylaxis (n = 11). Thrombin peak height is presented as the percentage of normal.

Figure 4

Associations between annual bleeding rate and thrombin potential in adult persons with hemophilia. (A) Annual bleeding rate according to thrombin potential in all patients included with on-demand treatment (n = 318). This group includes patients with mild (n = 228), moderate (n = 69), and severe hemophilia (n = 21). (B) Annual bleeding rate according to thrombin potential in patients with mild hemophilia treated on demand. (C) Annual bleeding rate according to thrombin potential in patients with moderate hemophilia treated on demand. (D) Annual bleeding rate according to thrombin potential in patients with severe hemophilia treated on demand. (E) Thrombin potential in patients receiving secondary/tertiary prophylaxis (n = 11). Thrombin potential is presented as the percentage of normal.

Figure 5

Thrombin peak height and thrombin potential according to clinical bleeding phenotype. (A) Thrombin peak height in hemophilia patients with a mild clinical bleeding phenotype (patients with an ABR of <5 and an AJBR of <3, and no prophylactic replacement therapy) or a severe clinical bleeding phenotype (patients with an ABR of ≥5 and/or an AJBR of ≥3 and/or those who receive secondary/tertiary prophylaxis). (B) Thrombin potential in patients with a mild clinical bleeding phenotype (patients with an ABR of <5 and an AJBR of <3, and no prophylactic replacement therapy) or a severe clinical bleeding phenotype (patients with an ABR of ≥5 and/or an AJBR of ≥3 and/or those who receive secondary/tertiary prophylaxis). NHA parameters are presented as the percentage of normal. Lines represent median with interquartile range. ∗∗∗∗P < .0001.

Figure 6

Association between bleeding rate and thrombin peak height and thrombin potential in children with hemophilia. (A) Bleeding rate according to thrombin peak height in children with hemophilia treated on demand (n = 20). (B) Bleeding rate according to thrombin potential in children with hemophilia treated on demand (n = 20). NHA parameters are presented as the percentage of normal.