Factor VII activity state in coronary artery disease.

In a recent study, Dalaker et al. (Br J Haematol 1985; 61:315-22) reported that men at high risk for cardiovascular disease had an increased mean level of factor VII procoagulant activity that was apparently attributable to an increase of a phospholipase C-sensitive form of factor VII in their plasma. We chose to investigate this phenomenon further by observing patients at high risk of coronary artery disease with assays that reflect the activity state of factor VII. We measured factor VII levels in patients before coronary arteriography and in normal subjects by an amidolytic assay (FVIIam assay) and by a standard clotting assay (FVIIc-A assay), both of which reflect the total amount of factor VII and are insensitive to activated factor VII, and by the method of Seligson et al. (Blood 1978;52:978-88) (FVIIc-B assay), which is sensitive to the presence of activated factor VII. In the FVIIc-A and FVIIam assays, the patients had a significantly higher mean value than the normal subjects; in the FVIIc-B assay, the patients had a significantly lower mean value than did the normal subjects. Moreover, the ratio of FVIIc-B to FVIIam, which is an indicator of the factor VII activity state, was much lower for the patients (0.70) than for the normal subjects (0.99). Thus, patients at high risk for coronary artery disease have an increased mean level of total factor VII that is not associated with an increase in activated factor VII and therefore presumably reflects an increase in zymogen factor VII.