Comparison of the impact of four generations of progestins on hemostatic variables

Role of tissue factor pathway inhibitor in hormone-induced venous thromboembolism

ABSTRACT

Exposure to higher levels of steroid hormones, like that in pregnancy or during combined hormonal contraception, increases the risk of venous thromboembolism. Development of resistance to activated protein C (APC) thought to be the underlying pathomechanism of this prothrombotic state. This coagulation phenomena is largely to be explained by the hormone-induced impairment of the protein S/ tissue factor pathway inhibitor (TFPI) leading to a less efficient inactivation of factor Va and factor VIIIa by APC. APC resistance and decreased protein S/TFPI function were associated with the risk of first as well as recurrent venous thromboembolism. Preexisting disturbances in these pathways are likely to predispose to thrombosis during hormone exposure and can persist over years after the thrombosis event.Further studies are necessary to investigate the predictive value of forgoing APC resistance and decreased protein S/TFPI function or an excessive alteration in these parameters during hormone intake on the development of hormone-induced venous thromboembolism.

Oral Contraceptives and Venous Thromboembolism: Focus on Testing that May Enable Prediction and Assessment of the Risk

Combined oral contraceptives (COCs) induce several changes in the levels of coagulation factors. The levels of procoagulant factors are often increased, while levels of anticoagulant factors are decreased. Fibrinolysis is also affected, even if the effect seems to be more counterbalanced by opposite regulation of profibrinolytic and antifibrinolytic factors. These effects on hemostasis are more pronounced with third- or fourth-generation COC compared with second-generation COC. Venous thromboembolism (VTE) risk increases when multiple risk factors, including genetic and environmental, are present simultaneously. COC use causes changes in coagulation that modify the prothrombotic state induced by preexisting hemostatic alterations in a supra-additive manner. Therefore, testing appears to be of importance not only before implementing COC but also to monitor any potential thrombogenicity induced by COC therapy. Inherited genetic factors, such as factor V Leiden, G20210A prothrombin mutation, antithrombin, protein C or protein S deficiencies, non-O blood group, as well as CYP2C9*2 and the rs4379368 mutations, have all been identified as genetic predictive risk factors of VTE in women. Nevertheless, the screening of these genetic biomarkers is not capable of assessing the phenotypic expression of the risk. This review will focus on the different options for screening the thrombogenic status in this population. Specific attention will be given to the endogenous thrombin potential-based activated protein C resistance, a test aiming at assessing the thrombogenicity induced by hormonal therapies and inherited or acquired thrombophilia.

Hemorheological mechanisms for increased thrombosis in subjects using gestodene

There are several possible mechanisms by which combined oral contraceptives (COC) use increase venous thromboembolism (VTE) risk. Melodene® is a monophasic COC containing the third-generation progestin Gestodene (GSD), which is associated with increased risk of VTE. Therefore, the aim of this study was to investigate the possible alterations in viscoelastic parameters of whole blood and plasma clots along with the biophysical characteristics of erythrocytes and specifically fibrin fibers in females using a COC containing GSD. GSD appeared to have a significant impact on the biophysical characteristics of fibrin fiber networks. When GSD is combined with ethinylestradiol the viscoelastic properties of whole blood clots tend to become more prothrombotic. The alterations to and aggregation of erythrocytes accompanied with spontaneous formation of a fibrin "blanket" provides a possible mechanism for the increased occurrence of "red" clots, which can lead to occlusions in the vascular system. Thus, the increased risk of VTE associated with these COCs can be attributed to these erythrocyte-and-fibrin-rich-clots occluding venous vessels. However, our findings also propose that these changes to the biophysical properties of both erythrocytes and fibrin, specifically spontaneous expansion of deformed fibrin networks, can also occlude vessels in the microcirculation, which could have lasting, subclinical complications for female users. We recommend that a thorough risk assessment, with specific focus on coagulation and other factors affecting fibrin formation, be done for each female before prescribing a GSD-containing COC. Females that "qualify" then need to be monitored on a regular basis to lower the risk of thrombotic events. RESEARCH HIGHLIGHTS: Gestodene in combination with ethinyl estradiol significantly impacts the biophysical characteristics of erythrocytes and fibrin fiber networks. These changes, specifically spontaneous expansion of deformed fibrin networks, can occlude vessels in the microcirculation, which could have lasting, subclinical complications for the female user. The changes observed for specifically erythrocytes and fibrin show that the hormone formulation investigated contribute to a thrombogenic profile for female users.

The effects of oral contraceptive usage on thrombin generation and activated protein C resistance in Saudi women, with a possible impact of the body mass index

BACKGROUND AND OBJECTIVES

The effect of oral contraceptive (OC) usage on coagulation has been studied worldwide. However, no such studies have been conducted in Saudi Arabia on Saudi women using OCs. The aim of this study was to investigate the effects of OC-induced changes of thrombin generation (TG) in the absence and presence of activated protein C (APC) or thrombomodulin (TM) in Saudi women.

METHODS

A total of 115 adult women, 47 on oral contraception (OC users) and 68 controls (not using OCs) were recruited from the obstetrics-gynecology outpatient clinic in Saudi Arabia. OCs that were used in this study include the following: Marvelon, Gynera, Cerrazetem, Yasmine, Microlut, Gracial and Diane. The plasma calibrated automated thrombinography (CAT) was used to determine TG which was expressed as endogenous thrombin potential (ETP; nM/min), lag time (min), peak (nM) and time-to-peak (ttpeak; min). In the presence of TM or APC, TG parameters were expressed relative to the parameters in the absence of TM or APC.

RESULTS AND CONCLUSION

As in other populations, our study demonstrated that OC usage induced prothrombotic changes in plasma of Saudi women, including resistance to the inhibitory actions of TM and APC. More specifically, OC usage in our population predominantly influenced TG and APC/TM sensitivity in overweight and obese individuals, a finding that needs confirmation in large cohort studies. The effects of APC and TM on TG parameters showed a positive association, and the correlation coefficients were higher in OC users for both ETP and peak values.