Inherited thrombophilia and stratification of ischaemic stroke risk among users of oral contraceptives

Thrombophilia Testing After Ischemic Stroke: Why, When, and What?

Thrombophilia testing is frequently performed after an ischemic stroke, particularly when cryptogenic. However, there is minimal evidence supporting a significant association between most conditions assessed through thrombophilia testing and ischemic stroke, and the rationale for thrombophilia testing in many clinical situations remains uncertain. In this topical review, we review and contextualize the existing data on the risks, predictors, and outcomes of thrombophilic conditions in patients with ischemic stroke. We report that inherited thrombophilias have an uncertain relationship with ischemic stroke. Conversely, antiphospholipid syndrome, an acquired immune-mediated thrombophilia, seems to be a strong risk factor for arterial thromboembolic events, including ischemic stroke, and especially among young patients. Our findings suggest that certain circumstances may warrant targeted thrombophilia testing, such as stroke in the young, cryptogenic stroke, and high estrogen states. Future prospective studies should investigate the utility and cost effectiveness of thrombophilia testing in various stroke settings, including among patients with patent foramen ovale; as well as the optimal secondary stroke prevention regimen in patients with confirmed thrombophilia, particularly if no other potential stroke mechanism is identified.

Ischemic Stroke in Young Adults

PURPOSE OF REVIEW

This article reviews current knowledge on epidemiology, risk factors and causes, diagnostic considerations, management, and prognosis of ischemic stroke in young adults (those 55 years old and younger).

RECENT FINDINGS

The incidence of ischemic stroke in young adults has been increasing since the 1980s, which has occurred in parallel with increasing prevalence of vascular risk factors and substance abuse among the younger population. Young adults have a considerably wider range of risk factors than older patients, including age-specific factors such as pregnancy/puerperium and oral contraceptive use. Behavioral risk factors such as low physical activity, excess alcohol consumption, and smoking are factors as well. More than 150 identified causes of early-onset ischemic stroke exist, including rare monogenic disorders. Several recent advances have been made in diagnosis and management of stroke in young adults, including molecular characterization of monogenic vasculitis due to deficiency of adenosine deaminase 2 and transcatheter closure of patent foramen ovale for secondary prevention. Compared with the background population of the same age and sex, long-term mortality in patients remains fourfold higher with cardiovascular causes underlying most of the deaths. The cumulative rate of recurrent stroke extends up to 15% at 10 years. Patients with atherosclerosis, high-risk sources of cardioembolism, and small vessel disease underlying their stroke seem to have the worst prognosis regarding survival and recurrent vascular events. Young stroke survivors also often have other adverse outcomes in the long term, including epilepsy, pain, cognitive problems, and depression.

SUMMARY

Systematic identification of risk factors and causes and the motivation of patients for long-term prevention and lifestyle changes are of utmost importance to improve the prognosis of early-onset ischemic stroke.

Re-Examining Genetic Screening and Oral Contraceptives: A Patient-Centered Review

The World Health Organization classifies combined hormonal contraception as an unacceptable health risk in the presence of a known thrombogenic mutation but advises against routine thrombophilia screening before initiating combined oral contraceptives (COCs) on the grounds of high screening costs and low prevalence. From the perspective of patient-centered care, we examine cost, prevalence, and other published arguments for and against thrombophilia screening before initiating COCs. Our patient-centered review draws on relevant empirical evidence concerning the advantages and disadvantages of thrombophilia screening, while placing the discussion in the broader context of evolving attitudes toward genetic testing and a shifting policy landscape that provides many women direct access to COCs and/or thrombophilia screening. Given variation in prior probabilities of thrombophilia, expected exposure to other risk factors for venous thromboembolism, attitudes towards risk, expected reactions to a positive test result, ability to pay, and concerns about genetic discrimination, we conclude that the current one-size-fits-most approach is not consistent with patient-centered care. Instead, we advocate for greater patient and provider education concerning the implications of thrombophilia screening. Moreover, we recommend offering patients optional thrombophilia screening before initiating COCs.

Testosterone Therapy, Thrombophilia, Venous Thromboembolism, and Thrombotic Events

In our sequential studies of 67 and 21 patients, testosterone therapy (TT) interacted with thrombophilia⁻hypofibrinolysis, leading to venous thromboembolism (VTE). Compared to 111 VTE controls not taking TT (VTE-no TT), the 67 and 21 cases were more likely (p < 0.05 for all) to have Factor V Leiden (FVL) heterogeneity (24% and 33% vs. 12%), the lupus anticoagulant (14% and 33% vs. 4%), and high lipoprotein(a) (33% vs. 13%, n = 21). After a first VTE and continuing TT, 11 thrombophilic cases had a second VTE despite adequate anticoagulation, 6 of whom, still anticoagulated, had a third VTE. The greatest density of thrombotic events was at three months after starting TT, with a rapid decline by 10 months. From <1 to 8 months after starting TT, 65% of VTE occurred, which may reflect TT-induced depletion of susceptible thrombophilic patients, leaving a winnowed residual group with fewer VTE events despite the continuation of TT. Before starting TT, we suggest screening for FVL, lipoprotein(a), and the lupus anticoagulant to identify patients at increased VTE risk, with an adverse risk-to-benefit ratio for TT. We suggest that TT should not be started in patients with known thrombophilia⁻hypofibrinolysis, and should not be continued after a first VTE. When TT is given to patients with thrombophilia⁻hypofibrinolysis, VTE may occur and then recur despite adequate anticoagulation.

From head to toe: Sex and gender differences in the treatment of ischemic cerebral disease

Stroke is a major cause of mortality and morbidity, particularly in the older ages. Women have a longer life expectancy and are more likely to experience stroke than men. Interestingly, the increased risk of ischemic stroke in women seems to be independent from age or classical cardiovascular risk factors. Notwithstanding the fact that stroke outcomes and survival are usually poorer in women, current evidence suggests that thrombolysis, antiplatelet and anticoagulant therapies are more beneficial in women than in men. A possible explanation of this paradox might be that females are often undertreated and they have fewer chances to be submitted to an effective and timely treatment for stroke than the male counterpart. The first step in the attempt to solve this obvious discrimination is surely to emphasize any reasons for differences in the therapeutic approach in relation to gender and then to denounce the lack of a sustainable motivation for them. In this article, we aimed to review the existing literature about gender-related differences on efficacy, administration and side effects of the most common drugs used for the treatment of ischemic stroke. The most striking result was the evidence that the therapeutic approach for stroke is often different according to patients' gender with a clear detrimental prognostic effect for women. A major effort is necessary to overcome this problem in order to ensure equal right to treatment without any sexual discrimination.

Association Between the 20210G>A Prothrombin Gene Polymorphism and Arterial Ischemic Stroke in Children and Young Adults-Two Meta-analyses of 3586 Cases and 6440 Control Subjects in Total

BACKGROUND

Previous data have shown that the 20210G>A polymorphism of the Factor II gene is related to an increased prothrombin level, which may in turn lead to a procoagulant state. The heterogeneous and multifactorial character of arterial ischemic stroke often results in contradictory reports describing the association between the 20210G>A polymorphism and arterial ischemic stroke in different populations. We performed a meta-analysis of available data addressing the relation between the FII 20210G>A polymorphism and arterial ischemic stroke, both in young adults and children.

METHODS

We searched PubMed using appropriate keywords. The inclusion criteria for the study were as follows: case-control study, study population consisting of children, study population consisting of young adults, arterial ischemic stroke confirmed by magnetic resonance imaging or computed tomography, and English language. The exclusion criteria included lack of genotype or allele frequencies, study design other than a case-control study, outcome definition other than arterial ischemic stroke, and previously overlapped patient groups. Finally, 30 case-control studies (14 in children and 16 in young adults) were included. Statistical analyses were conducted using R software. Heterogeneity between the studies was evaluated using the Dersimonian and Laird's Q test. In the case of significant between-studies heterogeneity, the pooled odds ratio was estimated with a random-effects model, otherwise a fixed-effects model was used.

RESULTS

The pooled analysis showed that carriers of 20210A allele (GA+AA genotypes) of the prothrombin gene are more common in arterial ischemic stroke patients, both in children and young adults, than in control subjects (P = 0.006; odds ratio, 1.83; 95% confidence interval, 1.19 to 2.80 and P = 0.001; odds ratio, 1.69; 95% confidence interval, 1.25 to 2.28, respectively).

CONCLUSIONS

The results of the present meta-analysis have proven that the FII 20210G>A polymorphism is associated with arterial ischemic stroke in both pediatric and young adult patients.

Combined oral contraceptives: the risk of myocardial infarction and ischemic stroke

BACKGROUND

Combined oral contraceptives (COCs) have been associated with an increased risk of arterial thrombosis, i.e. myocardial infarction or ischemic stroke. However, as these diseases are rare in young women and as many types of combined oral contraception exist, the magnitude of the risk and the effect of different hormonal contents of COC preparations remain unclear.

OBJECTIVES

To estimate the risk of myocardial infarction or ischemic stroke in users compared with non-users of different types, doses and generations of combined oral contraception.

SEARCH METHODS

We searched electronic databases (MEDLINE (1966 to July 08, 2015), EMBASE (1980 to July 08, 2015), Popline (1970 to July 08, 2015) and LILACS (1985 to July 08, 2015) for eligible studies, without language restrictions.

SELECTION CRITERIA

We included observational studies that recruited women in the reproductive age group (18 to 50 years) and compared the risk of myocardial infarction or ischemic stroke between users and non-users of COCs.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected relevant studies and extracted data. We pooled relative risks ()(combined odds ratios and one incidence rate ratio) and 95% confidence intervals (CIs) for myocardial infarction or ischemic stroke in users versus non-users of COCs.We combined the outcomes of myocardial infarction and ischemic stroke and also analysed these outcomes separately. Analyses were stratified according to estrogen dose and progestagen type.

MAIN RESULTS

In total, we identified 1298 publications through the search strategy. We included 28 publications reporting on 24 studies. COC users were at increased risk of myocardial infarction or ischemic stroke compared with non-users: relative risk (RR) 1.6 (95% CI 1.3-1.9).These RRs were similar for myocardial infarction (1.6, 95% CI 1.2 to 2.1) and ischemic stroke (1.7, 95% CI 1.5 to 1.9). The risks did not vary clearly according to the generation of progestagen or according to progestagen type. When we stratified preparations according to estrogen dose, the risk of myocardial infarction or ischemic stroke seemed to increase with higher doses of estrogen.

AUTHORS' CONCLUSIONS

This meta-analysis showed that the risk of myocardial infarction or ischemic stroke was 1.6-fold increased in women using COCs . The risk was highest for pills with > 50 microgram estrogen. When combined with the results of studies on the risk of venous thrombosis in COC users, it seems that the COC pill containing levonorgestrel and 30 μg of estrogen is the safest oral form of hormonal contraception.

Stroke in Young Women

In women ages 15-45 years, an additional set of risk factors are important in the pathogenesis of ischemic stroke. Some of these pertain strictly to women, and relate to exogenous hormones and pregnancy. Various other conditions are more common in women, which include migraine with aura, selected vascular disorders and autoimmune conditions. These differences do have implications for management in both the primary and secondary prevention of stroke in this age group.

Hormonal contraceptives and arterial disease: an epidemiological update

The cardiovascular safety of widely used combined hormonal contraceptives is still debated. Newer generations of oral formulations as well as non-oral contraceptives (transdermal and vaginal) have been recently evaluated in the context of cardiovascular disease. This review provides a summary of the association between combined oral contraceptives (COCs) and arterial diseases, with an emphasis on new formulations of hormonal contraceptives, as well as routes of administration. A systematic search of the Medline database was performed to find all relevant articles which included women who had widely use third generation pills, and the development of new progestins. Eligible articles published in English and reporting risk of arterial events (myocardial infarction [MI] and stroke) among users of hormonal contraceptives were reviewed. A quantitative assessment was made from included studies. Overall, current use of oral combined contraceptives increased the risk of MI and ischemic stroke (pooled OR: 1.7; 95% confidence interval [95% CI]: 1.2-2.3 and OR: 1.8; 95% CI: 1.2-2.8, respectively), but this was not associated with the risk of hemorrhagic stroke (OR: 1.1; 95% CI: 0.7-1.9). The increase in ischemic arterial disease was higher among first generation pill users compared with second or third generation pill users. In contrast, risk of ischemic arterial disease among current users of second or third generation pill was similar (p = 0.23 for MI risk and 0.99 for ischemic stroke). In conclusion, newer generation formulations of COCs, as well as the non-oral hormonal contraceptive, do not seem to be safer than second generation hormonal contraceptives.

Genetic determinants of juvenile stroke

Stroke is a heterogeneous multifactorial disorder. Although epidemiological data from twin and family studies provide substantial evidence for a genetic basis for stroke, the contribution of genetic factors identified so far is small. Large progress has been made in single-gene disorders associated with ischemic stroke, particularly at young age. The identification of NOTCH3 mutations in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) and of TREX1 mutations in retinal vasculopathy with cerebral leukodystrophy (RVCL) have led to new insights on lacunar stroke and small-vessel disease. Studies of sickle-cell disease have drawn attention to the importance of modifier genes and of gene-gene interactions in determining stroke risk, while there is now evidence that Fabry disease is an underdiagnosed cause of stroke. Furthermore, stroke is a well-known complication of several heritable connective tissue disorders, including Marfan's syndrome (FBN1 mutations) and Ehlers-Danlos syndrome type IV (COL3A1 mutations), which predispose to cervical artery dissection, the most frequent cause of cerebral ischemia at young age. By contrast, little is known about the genes associated with multifactorial stroke. The reported genome-wide association studies of ischemic stroke have shown that no single common genetic variant imparts major risk. Pharmacogenomic studies have uncovered genetic determinants of response to warfarin, statins and clopidogrel. Larger studies with samples numbering in the thousands are ongoing to identify common variants with smaller effects on risk. This approach will contribute to the identification of additional genes, novel pathways, and eventually novel therapeutic approaches to cerebrovascular disorders.

Cerebrovascular Events and Use of NuvaRing

Objective:

To report 2 cases, occurring within 1 month at a single institution, in which young women experienced a cerebrovascular event while using the hormonal contraceptive product NuvaRing (etonogestrel/ethinyl estradiol vaginal ring).

Case Summary:

The first patient presented to the emergency department (ED) with a 10-day history of right frontal headache. A computed tomography (CT) scan and magnetic resonance imaging showed evidence for right postcentral and cortical venous thrombosis. A hypercoagulable workup identified a heterozygous factor V Leiden mutation. The second patient presented to the ED with a same-day history of left frontotemporal headache extending into her left jaw and neck, numbness and clumsiness of right hand and right foot, and inability to make a comprehensible sentence. A CT angiogram showed occlusion of the internal and external carotid arteries. A hypercoagulable workup indicated no evidence of a thrombophilic disorder and a transesophageal echocardiogram indicated no cardioembolic source, resulting in a final diagnosis of a spontaneous carotid artery dissection. Both patients reported recent use of NuvaRing. The medication was discontinued during the hospital stay.

Discussion:

The use of hormonal agents for contraception carries a well-known risk of venous thrombosis; however, the impact this therapy has on the risk of arterial thrombosis and ischemic brain events is less understood. We found no previous reports of an ischemic brain event in association with NuvaRing use. The Naranjo probability scale indicated a possible relationship between the ischemic events and NuvaRing exposure in both patients.

Conclusions:

Risk factors should be evaluated appropriately prior to initiating any form of combined hormonal contraceptives, oral or vaginal, in young women.

A review of hereditary and acquired coagulation disorders in the aetiology of ischaemic stroke

The diagnostic workup in patients with ischaemic stroke often includes testing for prothrombotic conditions. However, the clinical relevance of coagulation abnormalities in ischaemic stroke is uncertain. Therefore, we reviewed what is presently known about the association between inherited and acquired coagulation disorders and ischaemic stroke, with a special emphasis on the methodological aspects. Good-quality data in this field are scarce, and most studies fall short on epidemiological criteria for causal inference. While inherited coagulation disorders are recognised risk factors for venous thrombosis, there is no substantial evidence for an association with arterial ischaemic stroke. Possible exceptions are the prothrombin G20210A mutation in adults and protein C deficiency in children. There is proof of an association between the antiphospholipid syndrome and ischaemic stroke, but the clinical significance of isolated mildly elevated antiphospholipid antibody titres is unclear. Evidence also suggests significant associations of increased homocysteine and fibrinogen concentrations with ischaemic stroke, but whether these associations are causal is still debated. Data on other acquired coagulation abnormalities are insufficient to allow conclusions regarding causality. For most coagulation disorders, a causal relation with ischaemic stroke has not been definitely established. Hence, at present, there is no valid indication for testing all patients with ischaemic stroke for these conditions. Large prospective population-based studies allowing the evaluation of interactive and subgroup effects are required to appreciate the role of coagulation disorders in the pathophysiology of arterial ischaemic stroke and to guide the management of individual patients.

Screening for coagulation disorders in patients with ischemic stroke

The role of coagulation disorders in the pathogenesis of (recurrent) ischemic stroke is uncertain. Therefore, the clinical utility of screening patients with ischemic stroke for these conditions and the therapeutic implications of a detected coagulation disorder in a patient who experienced ischemic stroke are uncertain. We reviewed the currently available data on the relationship between various inherited and acquired coagulation abnormalities (factor V Leiden and prothrombin G20210A mutations, deficiencies of protein C, protein S and anti-thrombin, hyperhomocysteinemia, the antiphospholipid syndrome and increased levels of fibrinogen) and ischemic stroke. Based on the existing evidence we discuss the usefulness of screening stroke patients for prothrombotic conditions and current recommendations regarding the optimal management of ischemic stroke patients in whom a coagulation disorder is found.

Stroke in women: risk and prevention throughout the lifespan

Women have a one in five chance of having a stroke during their lifetime. Although the majority of strokes occur in the oldest age groups, younger women have unique risks during their childbearing years because of pregnancy, preeclampsia, and the use of oral contraceptives. Fortunately, the absolute risk of stroke in these young women is low, but a history of preeclampsia during pregnancy or postpartum may be an indication of risk that carries over into later years after childbearing. In addition, menopause represents a risk because of the potential for increasing blood pressure, low-density lipoprotein cholesterol, abdominal obesity, insulin resistance, and decreasing high-density lipoprotein cholesterol. Early identification of stroke risk in women will help to minimize the effect of the stroke epidemic in older women.

Migraine and stroke: the role of oral contraceptives

The use of oral contraceptives (OCs) confers an increased risk for ischaemic stroke (IS). This risk slightly decreases, but remains significant, if low-dose formulations are used, particularly if other risk factors, such as hypertension or smoking, are associated. Some inherited prothrombotic conditions (e.g., Factor V Leiden, G20210A prothrombin or methylenetetrahydrofolate reductase C677T polymorphism) could also greatly increase the IS risk if present in OC users. Migraine, particularly with aura, is an independent risk factor for IS, and the patient's IS risk is probably affected by other individual risk factors (e.g., age, genetic predisposition to thrombosis, presence of patent foramen ovale or enhanced platelet aggregation) which seem to be over-represented in migraine patients. IS risk among migraineurs is further increased when OCs are currently used and can become very high if associated with smoking. Consequently, in 2004 the WHO stated in its 'Medical Eligibility Criteria for Contraceptive Use' that women suffering from migraine with aura at any age should never use OCs. Moreover, since the exposure to the effects of OCs may greatly increase the IS risk in some migraine subpopulations with specific personal characteristic, testing for these risk factors may allow for more accurate stratification of the population at risk before long-term use of OCs is prescribed.

Genetic polymorphisms for the study of multifactorial stroke

Single-gene disorders explain only a minority of stroke cases. Stroke represents a complex trait, which is usually assumed to be polygenic. On this topic, the role of a wide number of candidate genes has been investigated in stroke through association studies, with controversial results. Therefore, it is difficult for the clinician to establish the validity and the level of clinical applicability of the previously reported associations between genetic factors and stroke. This review is an update and an extensive analysis of the more recent association studies conducted in stroke. We evaluated a number of studies on several candidate genes (including F5, F2, FGA/FGB/FGG, F7, F13A1, vWF, F12, SERPINE1, ITGB3/PLA1/PLA2/ITGA2B, ITGA2, GP1BA, ACE, AGT, NOS3, APOE, LPL, PON1, PDE4D, ALOX5AP, MTHFR, MTR, and CBS), providing a final panel of genes and molecular variants. We categorized this panel in relation to the degree of association with stroke, supported by the results of meta-analyses and case-control studies. Our findings could represent a useful tool to address further molecular investigations and to realize more detailed meta-analyses.

Coagulation factor XIII gene variation, oral contraceptives, and risk of ischemic stroke

Prothrombotic conditions are associated with ischemic stroke in young women. In particular, the combination of oral contraceptive use and prothrombotic genetic variants appears to increase the risk of ischemic stroke. We performed a population-based case-control study in 190 women aged 20 to 49 years with ischemic stroke and 767 women without cardiovascular disease stratified for age, calendar year of the index event, and residence. A total of 4 variants of coagulation factor XIII subunit A and B genes (F13A1 and F13B) were investigated. The Phe allele of the F13A1 Tyr204Phe variant was present in 59 (31%) patients and 43 (6%) controls; the odds ratio for ischemic stroke was 9.1 for Phe/Phe and Phe/Tyr versus Tyr/Tyr genotype; the 95% confidence interval was 5.5 to 15. Homozygous genotypes (Phe/Phe) conferred a higher risk (odds ratio, 77; 95% confidence interval, 7.0-848) than heterozygous (Tyr/Phe) genotypes (odds ratio, 8.2; 95% confidence interval, 4.9-14). The risk of ischemic stroke was further increased in carriers of the 204Phe allele using oral contraceptives (odds ratio, 20; 95% confidence interval, 9-46) compared with nonusers with Tyr/Tyr genotype. In conclusion, the F13A1 204Phe allele was strongly associated with ischemic stroke in young women. Oral contraceptive use further increased the risk of ischemic stroke.