Effect of treatment with low-dose warfarin-aspirin on activated factor VII
GE Raskob, SS Durica, JH Morrissey, WL Owen and PC Comp
Department of Medicine, University of Oklahoma Health Sciences Center,
Oklahoma City 73190, USA.
Factor VII is an independent risk factor for ischemic heart disease. We
performed a prospective study to evaluate the effect of combined low- dose
warfarin-aspirin on activated factor VII (factor VIIa) and to determine if
abruptly stopping this treatment is associated with a rebound in the level
of factor VIIa. Thirty-three patients with clinically stable coronary
artery disease were treated with combined 3 mg warfarin and 80 mg aspirin
daily for 8 weeks. The factor VIIa level was measured before treatment,
weekly during treatment, and 2 weeks after stopping treatment. The mean
percent of pretreatment levels of factor VIIa for weeks 1 through 8 of
treatment were 60%, 60%, 72%, 70%, 71%, 70%, 74%, and 87%, respectively (P
< .05 compared with pretreatment for weeks 1 through 7 inclusive); 2
weeks after stopping treatment, the level was 122% (95% confidence interval
[CI]; 111% to 133%; P < .001 compared with pretreatment). The mean
percent level of factor VIIa on-treatment was 74% (P < .001). Factor
VIIa is reduced by 26% on average during treatment. This finding provides
further rationale for the antithrombotic effect of low-dose warfarin. The
results suggest a rebound in the factor VIIa level may occur after
treatment is stopped. The potential rebound and its clinical importance
should be evaluated by further studies.
Volume 85,
Issue 11,
pp. 3034-3039,
06/01/1995
Copyright © 1995 by The American Society of Hematology
