Changes in clot deformability— a possible explanation for the epidemiological association between plasma fibrinogen concentration and myocardial infarction

This study examined the rheological properties of fibrin gels formed by adding thrombin to plasma samples from 99 subjects with fibrinogen concentrations ranging from 1.45 to 4.14 g/l. A highly significant (r = 0.757; P < 0.001) inverse correlation was observed between plasma fibrinogen concentration and the extent of clot deformability as estimated from the final value of the storage modulus (G') of the fibrin gel when obtained by rheological analysis. A similarly significant correlation (r = 0.844; P < 0.001) was obtained using samples from 47 subjects in which fibrin cross-linking was blocked by addition of 0.1 mM iodoacetamide to inactivate factor XIIIa. The characteristics of the relationship between G' and fibrinogen concentration in the plasma samples was comparable with that observed when the fibrin gel was formed by adding thrombin to purified fibrinogen. These results suggest that the increased risk of myocardial infarction associated with an elevated plasma fibrinogen concentration may, in part, be explained on the basis of a decreased deformability of the fibrin clot formed.