Triglyceride dependence of factor VII coagulant activity in deep venous thrombosis

The effect of incubation of plasma with lipoprotein lipase on factor VII coagulant (FVII:C) activity was examined in 40 patients, 22 male and 18 female, aged 28 to 77 years, with history of venographically proven deep venous thrombosis (DVT). While the mean (+/-SEM) FVII:C activity of the 40 patients was 100.9 +/- 4.1%, 19 patients had FVII:C activity less than 100%, 11 had 100 to 120% activity and 10 patients had greater than 120% FVII:C activity. The mean triglyceride level of all the patients was 84.0 +/- 6.5 mg/dl. The FVII:C activity correlated significantly with triglyceride (r = 0.36; n = 40; p = 0.021). There was about 30% average loss of FVII:C activity upon incubation of plasma with lipoprotein lipase. The mean activity loss increased from 23.8% to 31.5% and 42.6% in patients whose FVII:C activity levels were less than 100%, between 100 and 120% and more than 120% respectively, the variation in the means being statistically significant (p < 0.001). While according to current opinion, FVII:C activity represents the total FVII mass (FVII plus FVIIa) and activity state, the present findings demonstrate a lipid dependence of FVII:C activity, and raises the possibility of a therapeutic option of controlling FVII:C by controlling triglyceride levels.