Hemostasis and cardiovascular risk. The British and European experience

There is evidence that increased reactivity of blood plasma to thrombogenic surfaces (hypercoagulability) may contribute to the risk of thrombotic occlusion of a coronary artery in coronary heart disease. The Northwick Park Heart Study found raised levels of factor VII coagulant (VIIc) activity and fibrinogen in men at high risk of a coronary event. Several other European studies have confirmed the latter finding, but the Northwick Park Heart Study is the only study to report formally on VIIc to date. Plasma VIIc is increased in the presence of hyperlipidemia and on a high fat diet, and falls with lipid-lowering therapy and a reduction in fat intake. Fibrinogen concentration is raised in smokers and decreases when the habit is given up. Thus, these markers of thrombogenic risk are readily controlled by standard preventive measures against coronary heart disease. Unresolved issues include: (1) whether the distinctive features of the Northwick Park VII bioassay improve the value of VIIc as a predictor of coronary heart disease; (2) the separate extent to which activation of factor VII and increases in factor VII concentration account for the raised VIIc in hyperlipidemia; (3) the basis of the raised fibrinogen in men at high coronary heart disease risk, even among nonsmokers; and (4) the usefulness of plasma levels of activation peptides of factors IX, X, and prothrombin as markers of thrombogenic risk.