[Atheroma and antithrombotic agents].

The clotting factors are thought to play a part in the development of atherothrombosis, not only in the formation of occlusive thrombosis but also in the progression of vessel wall lesions. Activated platelets participate in thrombus formation and stimulate the proliferation of smooth muscle cells via the growth factor that they liberate. Many therapeutic trials have been carried out with different platelet-inhibiting drugs and some have show a preventive effect on occlusive events. The role of platelet anti-aggregants in the prevention of vessel wall lesions is more difficult to demonstrate. Activation of the coagulation system or a defect in the fibrinolytic system result in the accumulation of intravascular and intraparietal fibrin. The increases in plasma concentration of factors such as the fibrinogen, factor VII, a fibrinolytic inhibitor, PAI-1, are considered to be markers of coronary risk. The preventive effect of low-dose vitamin K antagonists which reduce factor VII activity and the effect of metformin which counteracts insulin resistance and reduces PAI-1 concentrations, are at present under trial. Some platelet antiaggregants and lipid lowering drugs reduce fibrinogen, factor VII and PAI-1 concentrations. Results of therapeutic trials of these molecules are eagerly awaited.