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13:08
Measurement of Factor V Activity in Human Plasma Using a Microplate Coagulation Assay
Published on: September 9, 2012
Thrombin generation and phenotypic correlation in haemophilia A
C P Beltrán-Miranda1, A Khan, A R Jaloma-Cruz
1Department of Haematology, Imperial College London, Hammersmith Hospital, London, UK.
Summary
Thrombin generation assays reveal bleeding risks in hemophilia A (HA) patients, but cannot predict severity differences within families. Peak thrombin generation, not FVIII levels, may indicate critical defects in HA plasma.
Area of Science:
- Hematology
- Coagulation Science
- Clinical Chemistry
Background:
- Clinical presentation of hemophilia A (HA) varies despite similar factor VIII (FVIII) gene defects or activity.
- Clot-based FVIII assays offer limited information compared to thrombin generation assays.
Purpose of the Study:
- To investigate the relationship between thrombin generation assay results and clinical severity in HA patients.
- To explore the influence of prothrombotic risk factors on HA phenotype.
- To assess the utility of thrombin generation parameters in understanding HA variability.
Main Methods:
- Thrombin generation assay performed on platelet-poor plasma from 23 HA patients across nine families.
- Analysis of peak thrombin concentration, endogenous thrombin potential (ETP), generation rate, and lag-time.
- Inclusion of prothrombotic risk factors (FV Leiden, prothrombin G20210A), FVIII coagulant activity, and tissue factor polymorphisms.
Main Results:
- Significant inter-individual differences in thrombin generation were observed, but did not correlate with clinical phenotype.
- These thrombin generation differences impacted response to therapeutic FVIII, potentially explaining treatment consumption variations.
- Reduced peak and rate of thrombin generation, rather than FVIII:C or ETP, appeared critical in FVIII-deficient plasma.
Conclusions:
- Thrombin generation analysis is valuable for detecting bleeding tendency in HA.
- It does not predict modulation of hemorrhagic tendency within families.
- Further research incorporating vessel wall components, protein C, and platelets may enhance predictive capabilities.
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