Enhanced thrombin generation in women with a history of oral contraception-related venous thrombosis

Abstract

Introduction: In women who suffer venous thrombosis (VT) during oral contraceptive (OC) use, a transient risk factor (OC) is removed during the acute event, while most co-existing forms of thrombophilia persist and presumably continue to maintain hypercoagulability. The aim of this study was to establish if hypercoagulability persists long after OC-related VT and if it could be attributed to thrombophilia.

Materials and methods: 60 women (age 33.0 ± 8.5 years) were investigated 5 - 64 (median 33) months after OC-related VT (patients) and compared to 63 apparently healthy women (controls). All women were tested for thrombophilia, activated partial thromboplastin time (APTT), fibrinogen, D-dimer, P-selectin and C-reactive protein. Thrombin generation was measured by Technothrombin® TGA assay. Overall haemostasis potential (OHP) assay with overall coagulation potential (OCP) and overall fibrinolytic potential (OFP) as supplementary parameters were measured by repeated fibrin formation and degradation registration.

Results: In patients increased endogenous thrombin potential (4,205 ± 440 nM x min vs 4,015 ± 421 nM x min, p=0.017), increased OCP (22.6 ± 4.6 Abs-sum vs 20.8 ± 4.1 Abs-sum, p=0.025), shorter APTT (30.9 ± 3.8s vs 33.4 ± 3.6s, p<0.001) and lower antithrombin activity (99, 93-105% vs 104, 100-109%, p<0.05) were observed. Thrombophilia was observed in 22/60 (36%) patients and in 5/63 (7.9%, p<0.001) controls. The only significant difference between thrombophilic and non-thrombophilic patients was higher soluble P-selectin in the former subgroup (22, 20-33 μg/L vs 17, 12-22 μg/L, p=0.012).

Conclusions: In women with a history of OC-related VT persistent hypercoagulability was observed, which, however was not augmented by the presence of thrombophilia.

Keywords: APTT; ETP; OC; OCP; OFP; OHP; VT; activated partial thromboplastin time; endogenous thrombin potential; oral contraception; oral contraceptive(s); overall coagulation potential; overall fibrinolytic potential; overall haemostasis potential; thrombophilia; venous thrombosis.