Summary
We investigated the effect of oral contraceptives on thrombogenesis induced by subendothelium
of rabbit aorta (SE), exposed to flowing non-anticoagulated blood in an annular flow
chamber. Six healthy women on sequential contraceptive drugs (0.05 mg aethinylestradiol/day,
0.125 mg desogestrel/day) were compared with 6 women without hormonal contraception
and 6 men. On contraceptive drug treatment, blood values were significantly increased
for fibrinogen (2.6±0.2vsl.9±0.1 g/1) and fibrinopeptide A (3.9 ± 0.9 vs 0.9 ± 0.1
ng/ml), whereas antithrombin III was decreased (81 ± 4 vs 97 ± 6%). Fibrin deposition
on vascular subendothelium was more than four-fold increased when measured morphologically
(63.4 ± 2.5 vs 14.6 ± 6.8% coverage of SE surface with fibrin) as well as immunologically
(29.3 ± 2.2 vs 4.5 ± 1.9 pg fibrin/cm2 of SE). Thrombus volumes were more than two-fold increased in women with contraceptives
(9.0 ± 1.4 vs 3.7 ± 1.0 μm3/μm2).
Our study shows that during contraceptive drug treatment the exposure of flowing blood
to vascular subendothelium leads to excessive deposition of fibrin and platelet thrombi.
Measurement of blood interactions with subendothelium might be of predictive value
in hypercoagulable states such as contraceptive treatment.
Keywords
Thrombogenesis - Subendothelium - Contraceptives
