Different effects of oral contraceptives containing different progestogens on protein S and tissue factor pathway inhibitor

Risk of Stroke in Women Using Levonorgestrel-Releasing Intrauterine Device for Contraception

BACKGROUND

The commonly used combined hormonal contraceptives with progestins and ethinylestradiol are associated with an increased risk of ischemic stroke (IS). Progestin-only preparations, including levonorgestrel-releasing intrauterine devices (LG-IUDs), are not associated with an increased risk, and in smaller studies, the risk is even reduced. The risk of intracerebral hemorrhage (ICH) has never been investigated. We studied the risk of IS and ICH in women using LG-IUDs compared with women not using hormonal contraceptives.

METHODS

In this Danish historical cohort study (2004-2021), we followed nonpregnant women (18-49 years) registering incident IS and ICH in relation to use of LG-IUDs/nonuse of hormonal contraceptives utilizing Danish high-quality registries with nationwide coverage. Poisson regression models adjusting for age, ethnicity, education, calendar year, and medication use for risk factors were applied.

RESULTS

A total of 1 681 611 nonpregnant women contributed 11 971 745 person-years (py) of observation. Mean age at inclusion was 30.0 years; mean length of follow-up was 7.1 years; 2916 women (24.4 per 100 000 py) had IS; 367 (3.1 per 100 000 py) had ICH. Of these, 364 784 were users of LG-IUD contributing 1 720 311 py to the investigation; mean age at start of usage was 34.6 years. Nonusers of hormonal contraceptives contributed 10 251 434 py; mean age at inclusion was 30.0 years. The incidence rate of IS/ICH among LG-IUD users was 19.2/3.0 and among nonusers, it was 25.2/3.1 per 100 000 py. After adjustment, incidence rate ratio for IS was 0.78 (CI, 0.70-0.88), and for ICH it was 0.94 (CI, 0.69-1.28).

CONCLUSIONS

The use of LG-IUD was associated with a 22% lower incidence rate of IS without raising the incidence rate of ICH. The finding raises the question of whether levonorgestrel, in addition to its contraceptive properties, could have the potential to prevent IS.

Impact of Estetrol Combined with Drospirenone on Blood Coagulation and Fibrinolysis in Patients with Endometriosis: A Multicenter, Randomized, Open-Label, Active-Controlled, Parallel-Group Study

Venous thromboembolism is a serious safety concern in women using combined oral contraceptives; ethinyl estradiol (EE) is widely used as an estrogen. Estetrol (E4) is a native estrogen with selective tissue activity and exclusively produced by the fetal liver. This study used a multicenter, randomized, open-label, active-controlled, parallel-group design to evaluate the effects of E4 combined with drospirenone (DRSP) on coagulation and fibrinolysis in Japanese patients with endometriosis. Participants were randomized to receive either E4 15 mg/DRSP 3 mg or EE 20 µg/DRSP 3 mg for 12 weeks. E4/DRSP and EE/DRSP were administered orally once a day in a cyclic regimen, ie, 24-day active use followed by a 4-day hormone-free period, and a flexible extended regimen, respectively, and blood coagulation and fibrinolysis markers were measured. The effect on coagulation and fibrinolysis was considerably less in the E4/DRSP group than in the EE/DRSP group. Major anticoagulant proteins, protein S (free, total) and tissue factor pathway inhibitor (free), were reduced following EE/DRSP treatment. Consequently, thrombin generation determined by the activated protein C sensitivity ratio was increased by approximately 4-fold in the EE/DRSP group than in the E4/DRSP group. Eventually, the fibrinolysis cascade was triggered to compensate for disturbed coagulation, and D-dimer levels were 4.7-fold higher in the EE/DRSP group than in the E4/DRSP group. This study demonstrated that the effect of E4/DRSP on the blood coagulation and fibrinolysis cascades was significantly less than that of EE/DRSP in participants with endometriosis, a disease of women of advanced and reproductive age (jRCT2080225090, https://jrct.niph.go.jp/en-latest-detail/jRCT2080225090).

Protein C and protein S deficiencies are associated with increased risk of deep vein thrombosis in pregnant women using oral contraceptives

BACKGROUND

Oral contraceptives are commonly taken by women and are known to increase the risk of venous thromboembolism (VTE).

OBJECTIVE

The aim of this study was to investigate the association between oral contraceptive use and natural anticoagulants, that is, protein C (PC), protein S (PS), and antithrombin in pregnant women with deep vein thrombosis (DVT).

MATERIALS AND METHODS

This case-control study was conducted on 330 pregnant women, that is, cases 165 (who used oral contraceptives) and controls 165 (who did not use oral contraceptives). The levels of PC, PS, and antithrombin were measured and compared between the two groups. The use of different types of oral contraceptives and their association with DVT and PC and PS were also analyzed.

RESULTS

The study found that women with DVT had significantly lower levels of PC and PS compared with controls ( P  < 0.001). However, no significant difference was found in the levels of AT. Among the different types of oral contraceptives, first-generation progestin pills including Ethynodiol Diacetate, Norethindrone Acetate, Norethynodrel, and second-generation oral contraceptives (Lynestrenol, Levonorgestrel and Norgestrel) were not found to be associated with lower levels of PC and AT while Desogestrel, Norgestimate, and Gestodene (third-generation) were associated with lower levels of PS.

CONCLUSION

This study suggests that the use of contraceptives, particularly those containing Desogestrel, Norgestimate, and Gestodene, may be associated with a higher risk of thrombosis because of the associated lower levels of PS. Monitoring anticoagulant levels is crucial in preventing DVT in this population.

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.

Combined oral contraceptives containing estradiol valerate vs ethinylestradiol on coagulation: A randomized clinical trial

INTRODUCTION

Contraceptives containing ethinylestradiol (EE) induce changes in the coagulation system and are associated with a risk of venous thromboembolism. However, studies comparing the effects of combined oral contraceptives containing EE and low-potency estrogens (ie, estradiol [E₂ ] and estradiol valerate [EV]) on coagulation biomarkers are limited. This study represents secondary outcomes of a randomized trial comparing combined oral contraceptives containing EV + dienogest (DNG), EE + DNG, and DNG alone on selected coagulation biomarkers. We could compare the specific effects of the different estrogen components owing to the inclusion of preparations containing the same progestin.

MATERIAL AND METHODS

We enrolled 59 healthy, 18- to 35-year-old, non-smoking women, of whom three discontinued. The participants were randomly allocated to 9 weeks of continuous treatment with EV 2 mg + DNG 2-3 mg (n = 20), EE 0.03 mg + DNG 2 mg (n = 20), or DNG 2 mg (n = 19). Blood samples were collected at baseline and after 9 weeks. We assessed coagulation in vitro by thrombin generation using the Calibrated Automated Thrombogram. Thrombin generation was evaluated by lag time, time to thrombin peak, thrombin peak, and endogenous thrombin potential in response to tissue factor (1 pm). In vivo coagulation assessment was based on levels of prothrombin fragment 1 + 2 (F1 + 2) (thrombin generation) and D-dimer (fibrin turnover).

CLINICAL TRIAL REGISTRATION

NCT02352090.

RESULTS

Lag time and time to thrombin peak remained unaltered after exposure to EV + DNG, whereas EE + DNG shortened both lag time (mean percentage change -24%, 95% confidence interval [CI] -32% to -15%; p < 0.01) and time to thrombin peak (-26%, 95% CI -37% to -16%; p < 0.01). EV + DNG induced lower thrombin peak and endogenous thrombin potential than EE + DNG (peak; +45%, 95% CI 22%-67% vs +147%,95% CI 96%-198%; p < 0.01, and endogenous thrombin potential; +26%, 95% CI 15%-38% vs +64%, 95% CI 51%-76%; p < 0.01). Median F1 + 2 levels remained unchanged with EV + DNG (p = 0.22) but increased within normal ranges with EE + DNG (from 152 pmol/L, 95% CI 127-206] pmol/L to 194 pmol/L, 95% CI 149-250 pmol/L, p = 0.04). The within-group change in D-dimer levels was not significant in any of the groups. DNG alone did not affect these biomarkers.

CONCLUSIONS

Both in vitro and in vivo thrombin generation was lower after exposure to EV + DNG compared with EE + DNG. The lower thrombin generation measures after treatment with EV + DNG indicate less enhancement of coagulation potential and suggest that EV may be favorable to EE as a component of combined oral contraceptives.

Venous thrombosis with oral postmenopausal hormone therapy: Roles of activated protein C resistance and tissue factor pathway inhibitor

BACKGROUND

Oral postmenopausal hormone therapy (HT) increases the risk of venous thrombosis (VT). We postulated that activated protein C (APC) resistance induced by HT is one of the mechanisms causing VT, and also assessed the role of one of the main determinants of APC resistance (i.e., tissue factor pathway inhibitor [TFPI]).

METHODS

We performed a nested case-control study embedded within two Women's Health Initiative hormone trials. Women were randomized to hormone therapy or placebo. Biomarkers were measured at baseline and after 1 year in 217 cases and 817 controls.

RESULTS

Increased APC resistance and decreased TFPI at baseline were associated with VT (odds ratio 1.20-2.06). However, women with such prothrombotic profile at baseline did not have further increased risk of VT when randomized to HT compared with placebo. Although there was no change in APC resistance or TFPI in placebo group after 1 year, HT group showed prothrombotic changes in the biomarkers (i.e., an increase in APC resistance) (mean [standard deviation] 0.39 [0.54]) and decrease in TFPI (-0.21 [0.50]: free TFPI, -0.24 [0.22]: TFPI activity -0.22 [0.20]: total TFPI). However, HT induced prothrombotic change in biomarkers did not increase risk of VT.

CONCLUSION

Women with prothrombotic levels of APC resistance and TFPI at baseline were not at increased risk of VT when randomized to HT compared with placebo. This suggests that testing for these biomarkers before starting HT is not required. HT led to prothrombotic change in these biomarkers after one year, but this did not relate to increased risk of VT.

Progestin type affects the increase of heparanase level and procoagulant activity mediated by the estrogen receptor

STUDY QUESTION

Does progestin have an effect on heparanase level and procoagulant activity?

SUMMARY ANSWER

Progestin increases the heparanase level and procoagulant activity via the estrogen receptor and the magnitude of the effect depends on the progestin type.

WHAT IS KNOWN ALREADY

Users of combined oral contraceptives (COCs) containing third- and fourth-generation progestins have a higher risk of venous thrombosis compared to those employing second-generation progestins. Heparanase protein is capable of degrading heparan sulfate (HS) chains and enhancing activation of the coagulation system. We have previously demonstrated that estrogen enhances the expression and procoagulant activity of heparanase.

STUDY DESIGN, SIZE, DURATION

Estrogen and progestin receptor positive breast carcinoma cell lines: EMT6, T47D and MCF-7 were compared to the MDA-231 breast carcinoma cell line devoid of these receptors. This observational study incorporated 45 users of third-generation COCs progestins, 21 users of fourth-generation COCs progestins and 28 individuals not using hormonal therapy and not pregnant per history.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Second-generation progestin-levonorgestrel, third-generation progestin-desogastrel (DSG), an estrogen receptor antagonist-ICI 182.780 and a progestin receptor antagonist-mifepristone, were added to cell lines. Heparanase level and procoagulant activity, HS levels, tissue factor (TF) activity and factor Xa levels were evaluated in the plasma of the study group.

MAIN RESULTS AND THE ROLE OF CHANCE

Levonorgestrel and DSG increased heparanase levels in the cells and medium. The effect of DSG was more prominent and additive to that of estrogen. The effect was inhibited by ICI 182.780. In the plasma of COC users, heparanase procoagulant activity, HS levels, TF activity and factor Xa levels were significantly higher compared to controls. In COC pills containing the same dose of estrogen, the procoagulant effect of drospirenone was significantly stronger than that of DSG and gestodene.

LIMITATIONS, REASONS FOR CAUTION

The limitations of the study include a small number of participants in each study group, although the results are statistically significant and evaluated by several different coagulation parameters.

WIDER IMPLICATIONS OF THE FINDINGS

The study demonstrates a new mechanism through which progestin affects coagulation system activation and shows that this effect is progestin type-dependent. Development of a progestin derivative with an attenuated effect on heparanase procoagulant activity may reduce thrombotic risk.

STUDY FUNDING/COMPETING INTEREST(S)

No external funding was sought for this study. Y.N. is named in a European patent application No. IL201200027 filed on 18 January 2012. Other authors have no conflict of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Oral contraceptives and hormone replacement therapy: How strong a risk factor for venous thromboembolism?

Exogenous hormone therapies, such as combined oral contraceptives (COC) and hormone replacement therapy (HRT), cause blood hypercoagulability and are a risk factor for venous thromboembolism (VTE). There is controversy on how strong this "provoking" risk factor is, and how other risk factors may synergise VTE risk. We aim to review the latest literature on the risk of initial and recurrent VTE with COC and HRT use to provide guidance for decision-making about duration of anticoagulation, and guide future research efforts.

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.

Venous thrombosis at altitude presents with distinct biochemical profiles: a comparative study from the Himalayas to the plains

High-altitude (HA) hypoxia exposure is believed to induce venous thromboembolism (VTE) in otherwise healthy individuals, although this needs to be fully established. The present study aims to ascertain the role of HA exposure in aggravating any predisposition toward VTE and to explore whether the etiology of HA-induced VTE is different from that of VTE closer to sea level. We compared manifestation-matched male VTE patients from HA (HAPs) and VTE patients from the plains closer to sea level (SLPs) for 54 parameters, including coagulation-related, fibrinolytic, and thrombophilic variables, as well as markers for stress and inflammatory response and platelet and endothelial activation. Our results established an association between HA hypoxia and VTE in alterations of primarily hemostatic variables. Approximately 96% of HAPs presented with ≥10 altered parameters out of 54 studied compared with 7% of SLPs. Elevated platelet count, von Willebrand factor, and clotting factors and altered coagulation exhibited significant associations with VTE events and altitude exposure (all P < .05). Additionally, most VTEs at HA were associated with younger age groups, unlike those on the plains. A receiver operator characteristic curve analysis revealed differences between HAPs and SLPs for CD40 ligand (area under the curve [AUC], 0.90; 95% confidence interval [CI], 0.84-0.96]), P-selectin (0.79; 0.70-0.88), platelet factor-4 (0.90; 0.84-0.96), intracellular adhesion molecule-1 (0.86; 0.79-0.93), vascular cell adhesion molecule-1 (0.97; 0.95-0.99), vascular endothelial growth factor (0.87; 0.8-0.94), FLT4 (0.94; 0.89-0.99), and Toll-like receptor-2 (0.98; 0.96-1.0) (all P < .05). In conclusion, this study suggests that HA exposure perturbs the molecules associated with vascular integrity and contributes to the early onset of VTE.

Procoagulant activity in children and adolescents on intensive insulin therapy

BACKGROUND

Type 1 diabetes is associated with atherothrombosis, but limited data exist on procoagulant activity in the young. We investigated procoagulant activity in children/adolescents with type 1 diabetes using intensified insulin treatment compared with controls in a 5-year follow-up study, and further any associations with cardiovascular risk factors.

METHODS

The study included 314 diabetes children/adolescents and 120 healthy controls. Prothrombin fragment 1+2 (F1+2), D-dimer, tissue-factor-procoagulant-activity (TF-PCA), and tissue-factor-pathway-inhibitor (TFPI) were analyzed with ELISAs.

RESULTS

F1+2, D-dimer, and TF-PCA did not differ between the groups or correlate to HbA_1c in the diabetes group at either time points. TFPI was significantly higher in the diabetes group compared with controls both at inclusion and follow-up (both P < .001). In the diabetes group, TFPI correlated significantly to HbA_1c at both time points (r = 0.221 and 0.304, both P < .001). At follow-up, females using oral contraceptives had significantly elevated F1+2, D-dimer, and TF-PCA and lower TFPI compared to no-users (all P < .005), and females had lower TFPI (P = .017) and higher F1+2 compared with males (P = .052), also after adjusting for the use of oral contraceptives.

CONCLUSIONS

The current results show similar procoagulant activity in children/adolescents with type 1 diabetes compared with controls over a 5-year period, indicating that these children using modern intensified insulin treatment are not at high thrombotic risk at younger age. The elevated levels of TFPI in the diabetes group, related to hyperglycaemia, are probably reflecting increased endothelial activation. These findings highlight the significance of optimal blood glucose control in children/adolescents with type 1 diabetes, to maintain a healthy endothelium.

Proof of concept of a new scale for the harmonization and the standardization of the ETP-based APC resistance

BACKGROUND

The evaluation of the activated protein C resistance (APCr) based on the endogenous thrombin potential (ETP) is recommended during the development of steroid contraceptives. Results are usually expressed as "normalized APC sensitivity ratio" (nAPCsr) using a reference plasma that should achieve an ETP ratio of 0.1 in presence of exogenous APC. Because of the interassay variability, achieving exactly an ETP ratio of 0.1 in each run is almost impossible, which significantly affects the theoretical 0-10 scale of nAPCsr.

OBJECTIVES

To compare the nAPCsr to the nAPCsr10 , a newly proposed method to express the degree of APC resistance.

METHODS

Individual plasma samples (n = 854) were analyzed to compare nAPCsr and nAPCsr10 . These values were obtained using the validated ETP-based APCr assay.

RESULTS

The Spearman correlation between nAPCsr and nAPCsr10 had a coefficient of 0.99. Linear regression showed the following equation y = 0.9315*x + 0.03942 (r2  = .97). When differences (nAPCsr10 - nAPCsr) were plotted against nAPCsr10 , the mean difference equaled 0.16% or 4.95%. The correction obtained with the use of the nAPCsr10 showed that the results of the nAPCsr were statistically different (P < .0001).

CONCLUSIONS

This new scale provides a harmonization and normalization of the nAPCsr. Results show a better reproducibility with the nAPCsr10 . It avoids the additional variability and the unharmonized scale introduced by the use of a reference plasma. This adapted method for the calculation of the APC resistance could provide the regulatory and scientific bodies with more reproducible and harmonized evaluations.

Investigation of patients with unclassified bleeding disorder and abnormal thrombin generation for physiological coagulation inhibitors reveals multiple abnormalities and a subset of patients with increased tissue factor pathway inhibitor activity

INTRODUCTION

We have routinely used thrombin generation to investigate patients with unclassified bleeding disorder (UBD).

AIMS

To investigate haemostatic abnormalities in patients with UBD that had abnormal thrombin generation on at least one occasion.

METHODS

Investigation of 13 known UBD patients with thrombin generation and detailed haemostatic testing was undertaken including TFPI assays but also thrombomodulin and fibrinogen-γ.

RESULTS

12 females and 1 male were included. No patient had a platelet function disorder or coagulation factor deficiency that explained the bleeding phenotype, though 2 patients had factor deficiencies; a factor X of 0.41 IU/mL and a factor XI of 0.51 IU/mL. ThromboGenomics revealed variants for these factors but no other abnormalities. Patients were included who previously had either prolonged lag time or decreased endogenous thrombin potential (ETP) via high dose tissue factor (5 pmol/L) or low dose tissue factor (1.5 pmol/L) with corn trypsin inhibitor (CTI). Tissue factor pathway inhibitor (TFPI) activity was significantly increased (P < .001; increased in 8 patients) compared with controls and abnormalities in soluble thrombomodulin (2 patients), fibrinogen-γ (1 patient) and tPA (4 patients for each) were seen. Total and free TFPI levels were not increased. Mixing studies of patient plasma with 50:50 normal plasma for thrombin generation via low dose tissue factor failed to correct the ETP consistent with ongoing inhibition. Addition of an anti-TFPI antibody partially corrected thrombin generation to normal levels. TFPI sequencing was unremarkable.

CONCLUSION

TFPI activity may be increased in a subset of UBD patients. Further research studies are warranted in UBD patients for coagulation inhibitor abnormalities.

Sex hormones and venous thromboembolism - from contraception to hormone replacement therapy

The use of sex hormones such as combined oral contraceptives (COC) or hormone replacement therapy (HRT) increases the risk for venous thromboembolism (VTE) considerably, especially in patients with an increased intrinsic risk for thromboembolic complications. Despite public and media attention and increasing scientific evidence, prescription patterns seem to be hard to change. It is well recognized that the patient's baseline risk is the most relevant factor in the absolute risk for developing VTE. The relative risk increase associated with sex hormones, depends on the type and dosage of hormones, the route of application (oral, vaginal, transdermal), and for COC, on the specific combination of oestrogen and gestagen components. Consequently, a careful decision for or against any specific type of hormone treatment needs to be based on an assessment of the patient's risk profile (disposition) as well as on the treatment-associated risks and benefits (exposition). This review discusses the most common sex hormone treatments in contraception and HRT, the relevance for VTE risk patients, and strategies to counsel patients with regard to hormone use according to their risk profiles. Keywords: Oral contraceptives, hormonal contraception, hormone replacement therapy, venous thromboembolism.

Association between progestin-only contraceptive use and cardiometabolic outcomes: A systematic review and meta-analysis

Aims The association between progestin-only contraceptive (POC) use and the risk of various cardiometabolic outcomes has rarely been studied. We performed a systematic review and meta-analysis to determine the impact of POC use on cardiometabolic outcomes including venous thromboembolism, myocardial infarction, stroke, hypertension and diabetes. Methods and results Nineteen observational studies (seven cohort and 12 case-control) were included in this systematic review. Of those, nine studies reported the risk of venous thromboembolism, six reported the risk of myocardial infarction, six reported the risk of stroke, three reported the risk of hypertension and two studies reported the risk of developing diabetes with POC use. The pooled adjusted relative risks (RRs) for venous thromboembolism, myocardial infarction and stroke for oral POC users versus non-users based on the random effects model were 1.06 (95% confidence interval (CI) 0.70-1.62), 0.98 (95% CI 0.66-1.47) and 1.02 (95% CI 0.72-1.44), respectively. Stratified analysis by route of administration showed that injectable POC with a RR of 2.62 (95% CI 1.74-3.94), but not oral POCs (RR 1.06, 95% CI 0.7-1.62), was associated with an increased risk of venous thromboembolism. A decreased risk of venous thromboembolism in a subgroup of women using an intrauterine levonorgestrel device was observed with a RR of 0.53 (95% CI 0.32-0.89). No effect of POC use on blood pressure was found, but there was an indication for an increased risk of diabetes with injectable POCs, albeit non-significant. Conclusions This systematic review and meta-analysis suggests that oral POC use is not associated with an increased risk of developing various cardiometabolic outcomes, whereas injectable POC use might increase the risk of venous thromboembolism.

New functional assays to selectively quantify the activated protein C- and tissue factor pathway inhibitor-cofactor activities of protein S in plasma

Essentials Protein S is a cofactor of activated protein C (APC) and tissue factor pathway inhibitor (TFPI). There are no assays to quantify separate APC and TFPI cofactor activities of protein S in plasma. We developed assays to measure the APC- and TFPI-cofactor activities of protein S in plasma. The assays were sensitive to protein S deficiency, and not affected by the Factor V Leiden mutation.

SUMMARY

Background Protein S plays an important role in the down-regulation of coagulation as cofactor for activated protein C (APC) and tissue factor pathway inhibitor (TFPI). Aim To develop functional assays to quantify the APC- and TFPI-cofactor activities of protein S in plasma. Methods APC- and TFPI-cofactor activities of protein S in plasma were measured using calibrated automated thrombography in protein S-depleted plasma supplemented with a small amount of sample plasma either in the presence of anti-TFPI antibodies and APC (APC-cofactor activity) or at excess full-length TFPI without APC (TFPI-cofactor activity). Total and free protein S levels in plasma were measured by ELISAs. Results Average APC-cofactor activities of protein S were 113%, 108% and 89% in plasma from normal individuals (n = 15), FV Leiden heterozygotes (n = 14) and FV Leiden homozygotes (n = 7), respectively, whereas the average APC-cofactor activity of protein S in plasma from heterozygous protein S-deficient individuals (n = 21) was significantly lower (55%). Similar trends were observed for the TFPI-cofactor activity of protein S, with averages of 109%, 115% and 124% in plasma from individuals with normal protein S levels and different FV Leiden genotypes, and 64% in plasma from protein S-deficient patients. APC-cofactor activities of protein S correlated significantly with free and total protein S antigen levels, whereas TFPI-cofactor activities correlated less with protein S antigen levels. Conclusion We have developed functional protein S assays that measure both the APC- and TFPI-cofactor activities of protein S in plasma, which are hardly if at all affected by the FV Leiden mutation.

Pre-analytical issues in the haemostasis laboratory: guidance for the clinical laboratories

Ensuring quality has become a daily requirement in laboratories. In haemostasis, even more than in other disciplines of biology, quality is determined by a pre-analytical step that encompasses all procedures, starting with the formulation of the medical question, and includes patient preparation, sample collection, handling, transportation, processing, and storage until time of analysis. This step, based on a variety of manual activities, is the most vulnerable part of the total testing process and is a major component of the reliability and validity of results in haemostasis and constitutes the most important source of erroneous or un-interpretable results. Pre-analytical errors may occur throughout the testing process and arise from unsuitable, inappropriate or wrongly handled procedures. Problems may arise during the collection of blood specimens such as misidentification of the sample, use of inadequate devices or needles, incorrect order of draw, prolonged tourniquet placing, unsuccessful attempts to locate the vein, incorrect use of additive tubes, collection of unsuitable samples for quality or quantity, inappropriate mixing of a sample, etc. Some factors can alter the result of a sample constituent after collection during transportation, preparation and storage. Laboratory errors can often have serious adverse consequences. Lack of standardized procedures for sample collection accounts for most of the errors encountered within the total testing process. They can also have clinical consequences as well as a significant impact on patient care, especially those related to specialized tests as these are often considered as "diagnostic". Controlling pre-analytical variables is critical since this has a direct influence on the quality of results and on their clinical reliability. The accurate standardization of the pre-analytical phase is of pivotal importance for achieving reliable results of coagulation tests and should reduce the side effects of the influence factors. This review is a summary of the most important recommendations regarding the importance of pre-analytical factors for coagulation testing and should be a tool to increase awareness about the importance of pre-analytical factors for coagulation testing.

Tissue Factor Pathway Inhibitor, Activated Protein C Resistance, and Risk of Coronary Heart Disease Due To Combined Estrogen Plus Progestin Therapy

OBJECTIVE

To examine whether tissue factor pathway inhibitor or acquired activated protein C (APC) resistance influences the increased risk of coronary heart disease (CHD) due to estrogen plus progestin therapy.

APPROACH AND RESULTS

Prospective nested case-control study of 205 cases of CHD and 481 matched controls in the Women's Health Initiative randomized trial of estrogen plus progestin therapy. After multivariable covariate adjustment, both baseline tissue factor pathway activity (P=0.01) and APC resistance (P=0.004) were associated positively with CHD risk. Baseline tissue factor pathway activity and APC resistance singly or jointly did not significantly modify the effect of estrogen plus progestin on CHD risk. Compared with placebo, estrogen plus progestin decreased tissue factor pathway inhibitor activity and increased APC resistance but these changes did not seem to modify or mediate the effect of estrogen plus progestin on CHD risk.

CONCLUSIONS

Tissue factor pathway inhibitor activity and APC resistance are related to CHD risk in women, but may not explain the increased CHD risk due to estrogen plus progestin therapy. The data from this study do not support the clinical use of measuring these hemostatic factors to help stratify risk before hormone therapy.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00000611.

The second European evidenced-based consensus on reproduction and pregnancy in inflammatory bowel disease

Trying to conceive and being pregnant is an emotional period for those involved. In the majority of patients suffering from inflammatory bowel disease, maintenance therapy is required during pregnancy to control the disease, and disease control might necessitate introduction of new drugs during a vulnerable period. In this updated consensus on the reproduction and pregnancy in inflammatory bowel disease reproductive issues including fertility, the safety of drugs during pregnancy and lactation are discussed.

Multinational, multicentre, randomised, open-label study evaluating the impact of a 91-day extended regimen combined oral contraceptive, compared with two 28-day traditional combined oral contraceptives, on haemostatic parameters in healthy women

OBJECTIVES

To evaluate the impact of a 91-day extended regimen combined oral contraceptive (150 μg levonorgestrel [LNG]/30 μg ethinylestradiol [EE] for 84 days, followed by 10 μg EE for seven days [Treatment 1]) compared with two traditional 21/7 regimens (21 days 150 μg LNG/30 μg EE [Treatment 2] or 150 μg desogestrel [DSG]/30 μg EE [Treatment 3], both with seven days' hormone free), on several coagulation factors and thrombin formation markers.

METHODS

Randomised, open-label, parallel-group comparative study involving healthy women (18-40 years). The primary endpoint was change from baseline in prothrombin fragment 1 + 2 (F1 + 2) levels over six months.

RESULTS

A total of 187 subjects were included in the primary analysis. In all groups, mean F1 + 2 values were elevated after six months of treatment. Changes were comparable between Treatments 1 and 2 (least squares mean change: 170 pmol/L and 158 pmol/L, respectively) but noticeably larger after Treatment 3 (least squares mean change: 592 pmol/L). The haemostatic effects of Treatment 1 were comparable to those of Treatment 2 and noninferior to those of Treatment 3 (lower limit of 95% confidence interval [- 18.3 pmol/L] > - 130 pmol/L).

CONCLUSIONS

The LNG/EE regimens had similar effects on F1 + 2. Noninferiority was demonstrated between extended regimen LNG/EE and DSG/EE.

Mechanisms of hormonal therapy related thrombosis

There is now compelling evidence that use of oral contraceptives and postmenopausal hormonal therapies containing various estrogens is associated with a weak, but clinically relevant risk of both arterial and venous thrombosis. The increased risk is related to type and dose of both estrogen and combined progestagen and mode of delivery. Treatment induces mainly subtle changes in individual components of the coagulation and fibrinolytic systems, but the overall effect is the induction of a prothrombotic phenotype. This brief review summarizes some of the mechanisms responsible the prothrombotic effects of such treatment.

Genome-wide linkage scan in affected sibling pairs identifies novel susceptibility region for venous thromboembolism: Genetics In Familial Thrombosis study

BACKGROUND

Venous thromboembolism (VTE) is a multicausal disorder involving environmental and genetic risk factors. In many thrombophilic families the clustering of thrombotic events cannot be explained by known genetic risk factors, indicating that some remain to be discovered.

OBJECTIVES

We aimed to identify novel thrombosis susceptibility alleles in a large panel of small thrombophilic families: the Genetics In Familial Thrombosis (GIFT) study.

PATIENTS/METHODS

In the GIFT study, 201 families were recruited consisting of 438 siblings with an objectively confirmed VTE at a young age. Multipoint linkage analysis (402 SSR markers) and fine mapping were performed, followed by genotyping of tagging SNPs in positional candidate genes.

RESULTS

Established genetic risk factors such as factor V Leiden, ABO blood group non-O, prothrombin 20210A, fibrinogen gamma 10034T and deficiencies of antithrombin, protein C and protein S were more frequent in GIFT patients than in unselected VTE patients. Linkage supported the presence of novel thrombosis susceptibility loci on 7p21.3-22.2 (LOD score = 3.23) and Xq24-27.3 (LOD score = 1.95). Simulation analysis showed that the chr7 signal was genome-wide statistically significant (P = 0.022). Tagging SNPs (n = 157) in eight positional candidate genes (LOD drop 1.5 regions) were genotyped in GIFT patients and 332 healthy controls. Five chr7 SNPs associated with VTE. SNP THSD7A rs2074597 was responsible for part of the chr7 signal.

CONCLUSIONS

The GIFT panel is rich in established genetic risk factors for VTE, but genetic factors remain unidentified in many families. Genome-wide linkage failed to identify the previously established genetic risk factors for VTE, but identified a novel VTE susceptibility locus on chr7.

The effect of different hormonal contraceptives on plasma levels of free protein S and free TFPI

Use of combined oral contraceptives is associated with a three- to six-fold increased risk of venous thrombosis. Hormonal contraceptives induce acquired resistance to activated protein C (APC), which predicts the risk of venous thrombosis. The biological basis of the acquired APC resistance is unknown. Free protein S (PS) and free tissue factor pathway inhibitor (TFPI) are the two main determinants of APC. Our objective was to assess the effect of both hormonal and non-hormonal contraceptives with different routes of administration on free TFPI and free PS levels. We conducted an observational study in 243 users of different contraceptives and measured APC sensitivity ratios (nAPCsr), free TFPI and free PS levels. Users of contraceptives with the highest risk of venous thrombosis as reported in recent literature, had the lowest free TFPI and free PS levels, and vice versa, women who used contraceptives with the lowest risk of venous thrombosis had the highest free TFPI and free PS levels. An association was observed between levels of free TFPI and nAPCsr, and between free PS and nAPCsr. The effect of oral contraceptives on TFPI and PS is a possible explanation for the increased risk of venous thrombosis associated with oral contraceptives.

Characteristics and metabolic effects of estrogen and progestins contained in oral contraceptive pills

Estrogen and progestins have been used by millions of women as effective combined oral contraceptives. Oral contraceptives (OCs) modify surrogate markers such as lipoproteins, insulin response to glucose, and coagulation factors, that have been associated with cardiovascular and venous risk. Ethinyl-Estradiol (EE) exerts a stronger effect that natural estradiol (E2) on hepatic metabolism. New progestins with high specificity have been designed to avoid interaction with other receptors and prevent androgenic, estrogenic or glucocorticoid related side-effects. The risks and benefits of new progestins used in contraception depend upon their molecular structure, the type and dose of associated estrogen, and the delivery route. The lower impact of E2-based combinations on metabolic surrogate markers may result in an improved safety profile, but only clinical outcomes are relevant to assess the risk. Large surveillance studies are warranted to confirm this hypothesis.

Thrombotic risks of oral contraceptives

PURPOSE OF REVIEW

To inform about the risk of venous thromboembolism (VTE) of different hormonal contraceptives in different patient groups.

RECENT FINDINGS

Combined oral contraceptives (COCs) differ significantly regarding VTE risk depending on amount of estrogen and type of progestogen: COCs containing desogestrol, gestoden or drospirenone in combination with ethinylestradiol (so called third-generation or fourth-generation COCs) are associated with a higher VTE risk than COCs with ethinylestradiol and levonorgestrel or norethisterone (so called second-generation COCs). The VTE risk for transdermal COCs like vaginal ring (NuvaRing) or patch (Evra) is as high as for COCs of third or fourth generation. Progestogen-only contraceptive methods do not increase VTE risk significantly. New kinds of COC without ethinylestradiol but with estradiol valerat or estradiol showed a much lower degree of coagulation activation than 'classical' COC containing ethinylestradiol.

SUMMARY

Second-generation COCs should be the first choice when prescribing hormonal contraception.In patients with a history of VTE and/or a known thrombophilic defect, COCs are contraindicated, but progestogen-only contraceptives can be safely used in this patient group. Whether newer COCs with estradiol valerate or estradiol have a lower VTE risk remains to be elucidated.

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

This study was undertaken to evaluate the impact of progestins as part of low-estrogen (ethinyl estradiol [EE2] ≤35 μg) combined oral contraceptives (COCs) on hemostatic variables. One hundred ninety-five healthy women took oral contraceptives with following formulations: 35 EE2/norgestimate (NGM), 35 EE2/cyproterone acetate, 35 EE2/norethisterone, 30 EE2/levonorgestrel, 30 EE2/drospirenone (DRSP), 20 EE2/gestodene, and 20 EE2/DRSP, for 6 months. Hemostatic assays (prothrombin time, activated partial thromboplastin time, fibrinogen, resistance to activated protein C ratio, protein C, protein S, factor VIII [FVIII], antithrombin, plasminogen, α2-antiplasmin, inhibitor of plasminogen activator type 1 [PAI-1] and d-dimers) were performed in 3 time points: at baseline, after 3, and 6 cycles. For each formulation, results were compared according to baseline values, intergroup analysis, and the amount of estrogen or progestin component. Most of the variables were changed except FVIII. Significant difference between oral contraceptives was found in antithrombin, protein C, protein S activities, and PAI-1 values, but changes were mostly within reference range.

Oral versus vaginal combined hormonal contraceptives' effect on coagulation and inflammatory biomarkers among young adult women

In order to compare the effect of combined oral contraceptive (COC) and combined vaginal contraceptive (CVC) methods on the inflammation and procoagulation, we recruited female participants in 3 groups: control participants, COC users, and CVC users. We measured different blood biomarkers. The users of both COC and CVC had higher levels of C-reactive protein (P < .0001) and factor VII (P < .0001). However, CD40 ligand was only higher for COC users (P < .0001) and not the CVC users. Even though the levels of thrombin/antithrombin III were not higher for COC and CVC users, as compared to the controls, CVC users had higher levels as compared to COC users (P = .0327). As compared to the control group, we observed higher levels von Willebrand factor among CVC users but not the COC users. Longitudinal studies with larger sample size are needed to better assess the inflammatory and procoagulation response due to CVC use.

Tissue factor pathway inhibitor, activated protein C resistance, and risk of ischemic stroke due to postmenopausal hormone therapy

BACKGROUND AND PURPOSE

To test whether changes in plasma tissue factor pathway inhibitor (TFPI) levels or activated protein C resistance (normalized activated protein C resistance ratio [nAPCsr]) modify the increased risk of ischemic stroke due to postmenopausal hormone therapy.

METHODS

Nested case-control study of 455 cases of ischemic stroke and 565 matched control subjects in the Women's Health Initiative trials of postmenopausal hormone therapy.

RESULTS

Baseline free TFPI was associated with ischemic stroke risk (OR per SD increase, 1.17; 95% CI, 1.01-1.37; P=0.039), but baseline nAPCsr was not (OR per SD increase, 0.89; 95% CI, 0.75-1.05; P=0.15). Baseline TFPI levels and nAPCsr did not modify the effect of postmenopausal hormone therapy on ischemic stroke. Treatment-induced mean changes of -28% in free TFPI and +65% in nAPCsr did not change the risk of ischemic stroke (interaction P=0.452 and 0.971, respectively). In subgroup analyses, baseline nAPCsr was inversely associated with lacunar strokes (OR per SD increase, 0.74; 95% CI, 0.57-0.96; P=0.025) and baseline free TFPI interacted with treatment to increase large vessel atherosclerotic strokes (P=0.008).

CONCLUSIONS

Procoagulant changes in TFPI or nAPCsr do not modify the increased ischemic stroke risk due to postmenopausal hormone therapy. Clinical Trial Registration- URL: www.clinicaltrials.gov. Unique identifier: NCT 00000611.

Hormonal contraception in thrombophilic adolescents: risk of thrombosis and recommendations

About 3.2 million women in Germany are between 14 and 19 years old representing about 19% of women. 55% of them use combined oral contraception (COC). The risk of venous thromboembolism (VTE) during the use of COC is increased 2-6 times. For thrombophilic patients depending on the kind of thrombophilic defect it is much higher. Pregnancy and postpartum period lead to a much higher increase of VTE than any COC use at all, both in women with and without thrombophilic defect. VTE risk in COC is highly dependent on the content of ethinylestradiol (EE) and the kind of progestagen used in COC. Progestagen-only contraceptives (POC) do not increase the VTE risk, since they do not activate the coagulation system.

CONCLUSION

It is not justified to withhold any hormonal contraception to thrombophilic women, especially considering the much higher VTE risk in (maybe unintended) pregnancy. Adolescents thrombophilic women should rather be informed about the opportunity to use POC.

Metabolic effects of contraceptive steroids

Estrogen and progestins have been used by millions of women as effective combined contraceptives. The safety of hormonal contraceptives has been documented by years of follow-up and serious adverse events that may be related to their use are rare in the young population exposed to these agents. The balance between the benefits and the risks of contraceptive steroids is generally positive in particular when comparing to the risks of pregnancy and especially in women with risk factors. The metabolic changes induced by the synthetic steroids used in contraception, such as lipoprotein changes, insulin response to glucose, and coagulation factors have been considered as potential markers of cardiovascular and venous risk. Observations of these effects have led to modifications of the composition of hormonal contraceptive in order to minimize these changes and hence potentially decrease the risks. The synthetic estrogen Ethinyl-Estradiol (EE) exerts a stronger effect that natural estradiol (E2) on hepatic metabolism including estrogen-dependent markers such as liver proteins. This stronger hepatic impact of EE has been related to its 17α-ethinyl group which prevents the inactivation of the molecule and results in a more pronounced hepatic effect of EE as compared to estradiol. Due to its strong activity, administering EE via a non-oral route does not prevent its impact on liver proteins. In order to circumvent the metabolic changes induced by EE, newer products using more natural compounds such as estradiol (E2) and estradiol valerate (E2V) have been introduced. The synthetic progestins used for contraception are structurally related either to testosterone (T) (estranes and gonanes) or to progesterone (pregnanes and 19-norpregnanes). Several new progestins have been designed to bind more specifically to the progesterone receptor and to minimize side-effects related to androgenic, estrogenic or glucocorticoid receptor interactions. Dienogest (DNG), and drospirenone (DRSP) and the 19-norpregnanes including Nestorone® (NES), nomegestrol acetate (NOMAc) and trimegestone (TMG) have been combined with estrogen either EE or E2 or estradiol valerate (E2V). Risks and benefits of the newer progestins used in contraception depend upon the type of molecular structure, the type and dose of estrogen associated in a combination and the route of administration. The lower metabolic impact of estradiol-based combinations may result in an improved safety profile, but large surveillance studies are warranted to confirm this plausible hypothesis. So far, the contraindications and warnings for use of current COCs also apply to the estradiol-based COCs.

Controversies in postpartum contraception: when is it safe to start oral contraceptives after childbirth?

The timely initiation of contraception postpartum is an important consideration for breastfeeding and non-breastfeeding women; many women prefer oral contraceptive pills to other methods. In breastfeeding women, combined hormonal pills are not recommended prior to 6 weeks postpartum, due to effects on milk production. Although progestogen-only pills do not adversely affect milk, lack of data regarding possible effects on infants exposed to progestogens in breastmilk renders timing of initiation of this method controversial. In non-breastfeeding women, elevated risk of venous thromboembolism restricts use of combined hormonal pills prior to 21 days postpartum. From 21 to 42 days, use of combined hormonal pills should be assessed based on a woman's personal venous thromboembolism risk profile; after 42 days postpartum there is no restriction in the use of combined hormonal pills for otherwise healthy women. Non-breastfeeding women may safely use progestogen-only pills at any time during the postpartum.

Risk Factors for Heart Attack, Stroke, and Venous Thrombosis Associated With Hormonal Contraceptive Use

The search for a safe and effective method of contraception has been ongoing for centuries. During the last century, a variety of hormonal contraceptives, including combined hormonal oral contraceptives (COCs), have been introduced into the market. COCs have evolved through modifications of different hormonal components to minimize the risk of thrombotic events including stroke, myocardial infarction, and venous thrombosis. The evolution of COC development led to the reduction in the estrogen dose, in an attempt to lower the risk of vascular diseases. Although the risk of thrombotic events due to COC use has been substantially reduced since their inception, the quest for developing safer methods of birth control continues. It is of great interest to study coagulation effects of newer COCs, as well as progestin only, as rigorously as older COCs.

Atherothrombosis in 2 Vascular Territories in a Young Woman: Importance of Thrombophilia Testing

The diagnosis and management of complex and multiple inherited thrombophilias is still a challenge for the clinicians involved in this field, clinical events being the result of the interaction between genes, environmental or other acquired factors, and age. Moreover, various clinical manifestations as regards severity or type of event (venous or arterial thrombotic event, obstetrical complications) are cited in these patients. We present the case of a 20-year-old woman, with a 2-month history of third-generation contraceptive use and with recently diagnosed hypercholesterolemia, who presented ischemic events in 2 arterial territories: acute left lower limb ischemia and silent myocardial infarction. Screening tests for thrombophilia, including genetic testing, showed moderate hyperhomocysteinemia and 2 inherited thrombophilic defects. Invasive investigation of the coronary arteries showed the presence of advanced atherosclerotic disease. Management of this complex thrombophilia includes lifetime oral anticoagulation as well as a homocysteine-lowering strategy comprising lifestyle modification and group B (folic acid, B6, B12) vitamin supplementing.

Mechanisms of estrogen-induced venous thromboembolism

The use of oral contraceptives (OC) is a well established risk factor for venous thrombosis. It has been known for many years that almost all haemostatic parameters i.e. plasma levels of coagulation factors, anticoagulant proteins and proteins involved in the fibrinolytic pathway change during OC use. The discovery of several risk factors of venous thrombosis in the 1990s shed new light on the association between the effects of OC on the haemostatic system and the increased risk of venous thrombosis. In this review, we summarize the current knowledge on the effects of different kinds of hormonal contraceptives (OC, transdermal contraceptives, vaginal ring and levonorgestrel-releasing intrauterine device) on haemostatic variables and the relationship between the changes of these variables and the risk of venous thrombosis.

Thrombophilic conditions in the adolescent: the gynecologic impact

As Virchow's triad suggests, a fine balance exists between the vascular wall, intravascular contents, and dynamic blood flow, such that a shift in this balance predisposes to thrombosis. Although thromboembolic events (TEs) are relatively infrequent in adolescents, the morbidity and mortality associated with TEs can be significant. Over the past 15 years, TEs and inherited and acquired thrombophilic conditions underlying them have become increasingly recognized in teens at risk, with combined hormonal contraception constituting one of the most significant of these risk factors. Therefore, managing gynecologic problems in teens who have thrombophilic conditions can be challenging. It is important to have a clear understanding about safe options available to help address adolescent gynecologic concerns in this setting and to manage situations collaboratively with a hematologist.

Mechanisms of thrombosis related to hormone therapy

Combined oral contraceptives and combined oral postmenopausal hormone therapy are associated with a weak, but clinically significant risk of arterial and venous thrombosis (VT). The effects are related to dose of estrogen and type of progestin. The main effects are increase in markers of activated coagulation, reduction in coagulation inhibitors, and acquired activated protein C resistance. Reduction in tissue factor pathway inhibitor (TFPI) is probably an important mechanism, which predicts activation of coagulation and acquired resistance to activated protein C. Coagulation markers should be used as intermediate or surrogate markers in early pharmacodynamic studies to evaluate the risk associated with new formulations.

Cyproterone acetate- and ethinyloestradiol-containing oral contraceptive as a risk factor for upper extremity deep venous thrombosis-a case report

Deep venous thrombosis of the upper extremity (UEDVT) is a rare variety of deep venous thrombosis. Compared to lower-extremity deep venous thrombosis, less is known about the risk factors for primary UEDVT. We report on a 27-year-old woman with UEDVT extending from the jugular and subclavian veins to the elbow. The thrombosis was possibly provoked by a shoulder trauma, in combination with heterozygosity for the prothrombin G20210A mutation and a protein S-deficiency, which may have been induced by the use of a cyproterone acetate- and ethinyloestradiol (CPA/EE)-containing oral contraceptive.