Platelets, fibrinolytic activity and clotting factors

• platelets: platelet activation and aggregation may be as a result of the rupture of an atherosclerotic plaque with exposure of subendothelial collagen. Platelet aggregation reduces coronary blood flow in three ways:
  • platelets form part of an occlusive thrombus
  • platelet microemboli may reduce perfusion
  • mediators such as thromboxane A2 may induce vasospasm Anti-platelet drugs such as aspirin are effective in prophylaxis against ischaemic heart disease.
    
    
• fibrinolytic activity: low fibrinolytic activity is associated with the development of ischaemic heart disease in young men. This factor may exert a long-term influence by impairing the removal of fibrin deposits that contribute to atherogenesis.
  
  
• clotting factors and fibrinogen: high levels of fibrinogen and high factor VII activity are both independently associated with an increased incidence of ischaemic heart disease.

Ref: (1) Meade TW et al.Fibrinolytic activity, clotting factors, and long-term incidence of ischaemic heart disease in the Northwick Park Heart Sudy.Lancet (1993);324:1076- 1079.