Fibrinogen and coronary risk.

The notion that fibrinogen is strongly, consistently, and independently related to coronary risk has been widely accepted. The evidence is based on numerous prospective epidemiological studies and clinical observations. However, the reasons why fibrinogen is elevated in coronary disease and in atherosclerosis are only incompletely understood. All cells involved in the atherogenetic process are able to produce cytokines which induce an acute phase reaction. The potential pathophysiologic mechanisms by which elevated fibrinogen levels mediate coronary risk are manifold: It forms the substrate for thrombin and represents the final step in the coagulation cascade; it is essential for platelet aggregation; it modulates endothelial function; it promotes smooth muscle cell proliferation and migration; it interacts with the binding of plasminogen with its receptor; and finally it represents a major acute phase protein. Whether or not fibrinogen is causally involved in atherothrombogenesis still remains to be determined, and even though other unsolved issues await conclusive answers, fibrinogen has emerged as an important additional marker of coronary risk.