Spatial dynamics of fibrin clot formation in non-stirred system activated by glass
surface was studied as a function of FIX activity. Haemophilia B plasma was obtained from
untreated patients with different levels of FIX deficiency and from severe haemophilia B patient
treated with FIX concentrate (Ahemphil B) during its clearance with half-life t1/2=12 hours. As
reported previously (Ataullakhanov et al. Biochim Biophys Acta 1998; 1425: 453-468), clot
growth in space showed two distinct phases: activation and propagation. The activation phase is
characterized by the time required to start clot growth from the activator, while the characteristic
parameter of the propagation phase is the clot elongation rate. This rate reaches steady state in
approximately ten minutes after the beginning of growth. In haemophilia B plasma, clot
formation is substantially impaired: clot starts to grow from the activating surface later than in
healthy donor plasma, and its propagation rate is considerably lower. The most significant
abnormalities in clot growth kinetics are observed at FIX activity below 10% of normal.
Simulation of these experiments was performed theoretically using a detailed biochemical model
(Panteleev et al. Biophys J 2006; 90: 1489-1500) adapted for experimental conditions used.
Suitability of the assumptions used to describe triggering contact activation was verified.