title: Effect of treatment with low-dose warfarin-aspirin on activated factor VII.
abstract: 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.
authors.affiliation: Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City 73190, USA.
authors.forename: G E
authors.initials: GE
authors.lastname: Raskob
authors.forename: S S
authors.initials: SS
authors.lastname: Durica
authors.forename: J H
authors.initials: JH
authors.lastname: Morrissey
authors.forename: W L
authors.initials: WL
authors.lastname: Owen
authors.forename: P C
authors.initials: PC
authors.lastname: Comp
mesh_terms: D000368:Aged; D001241:Aspirin / Q000008:administration & dosage / Q000627:therapeutic use*; D003327:Coronary Disease / Q000188:drug therapy*; D004359:Drug Therapy, Combination; D015942:Factor VIIa / Q000032:analysis / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D011517:Prothrombin Time; D012307:Risk Factors; D016896:Treatment Outcome; D014859:Warfarin / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D014859:Warfarin; D015942:Factor VIIa; D001241:Aspirin