Clot formation in the vessel, supplying heart muscle with blood, is the most often reason for sudden death. Is it possible to prevent it? It is, but to do this we need to understand the reason of clot formation thoroughly.
 

Under certain conditions liquid blood can transform to solid state. Blood-dotting sequence is responsible for this transformation. This sequence consists of 12 factors and works on chain reaction principle. Stress, vessel injury, for example, initiates cascade of chemical reactions. The main reaction is thrombin protein formation, which finally results in fibrin protein polymerization leading to clot formation. There also exists blood anti-coagulation system, which stops the process, leaving the blood liquid. The balance of these two systems depends on blood biochemical composition, but it’s not the only factor.
 

The scientists from Hematology Science Centre (G.T. Guria and A.P. Guzevatykh) proved that blood-dotting system is influenced by hemodynamics, i.e. the way blood moves along the vessels. The researchers used mathematical and physical models and showed that clots may form due to blood pressure drop below some limit or due to blood viscosity increase. The clot grows with time and changes the way blood moves along the vessel. And blood current changes, in their turn, accelerate clot formation. Feedback appears and causes the vessel to become totally shut.
 

The authors have performed an experiment testing the mathematical model, linking blood hemodynamics parameters to blood coagulation process. Instead of a blood vessel they used a tube with flowing thrombocyte-enriched plasma. The scientists changed hydrodynamic parameters of the plasma flow and observed the clot formation. The video record of the experiment matched the pictures resulted from computer mathematical modeling.
 

Blood-dotting sequence is also activated through a vessel spasm, which can appear due to stress. And atherosclerotic patients are in the risk group. Today atherosclerosis is perhaps the most common disease. For some reasons cholesterol plates settle on the vessel walls, then the vessel narrows leading to suffering of blood supply of the vital parts with all that it implies. But sometimes a clot forms where the vessel narrows (stenosis site). Sclerotic deposits are evidently influencing blood-dotting sequence. But how? The mathematical model, developed by A.P. Guzevatykh, shows how.
 

Small sclerotic plates do not significantly change vessel’s blood flow and cause no coagulation. But when such plate grows seriously, it changes vessel’s shape and causes blood to flow it around. The plate forms the narrow place behind which thrombin (coagulation activator) concentration increases. When it reaches its threshold, the blood-dotting sequence launches, and, as a result fibrin polymerizes and the vessel turns to be blocked by a clot.
 

The developed model allows predicting blood response to various stresses. For example, it can tell whether an atherosclerotic patient can decrease blood pressure, when it’s high, in order no to provoke clotting. Or whether the patient can take diuretics that increase blood viscosity. The model can also predict the influence of an emotional stress on blood-dotting system. According to Mr. Guria, resuscitators, who work in the Hematology Centre, take an active interest in the model and have already put it into practice.
 

The scientists think that in future it will be possible to simulate not only clot formation, but also its resolution (lysis). Then doctors will be able to see how clot behaves in the patient’s vessel and find correct individual treatment for a patient.