Inherited thrombophilic disorders in young adults with ischemic stroke and patent foramen ovale

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.

Guidelines for the primary prevention of stroke: a guideline for healthcare professionals from the American Heart Association/American Stroke Association

BACKGROUND AND PURPOSE

This guideline provides an overview of the evidence on established and emerging risk factors for stroke to provide evidence-based recommendations for the reduction of risk of a first stroke.

METHODS

Writing group members were nominated by the committee chair on the basis of their previous work in relevant topic areas and were approved by the American Heart Association (AHA) Stroke Council Scientific Statement Oversight Committee and the AHA Manuscript Oversight Committee. The writing group used systematic literature reviews (covering the time since the last review was published in 2006 up to April 2009), reference to previously published guidelines, personal files, and expert opinion to summarize existing evidence, indicate gaps in current knowledge, and when appropriate, formulate recommendations using standard AHA criteria (Tables 1 and 2). All members of the writing group had the opportunity to comment on the recommendations and approved the final version of this document. The guideline underwent extensive peer review by the Stroke Council leadership and the AHA scientific statements oversight committees before consideration and approval by the AHA Science Advisory and Coordinating Committee.

RESULTS

Schemes for assessing a person's risk of a first stroke were evaluated. Risk factors or risk markers for a first stroke were classified according to potential for modification (nonmodifiable, modifiable, or potentially modifiable) and strength of evidence (well documented or less well documented). Nonmodifiable risk factors include age, sex, low birth weight, race/ethnicity, and genetic predisposition. Well-documented and modifiable risk factors include hypertension, exposure to cigarette smoke, diabetes, atrial fibrillation and certain other cardiac conditions, dyslipidemia, carotid artery stenosis, sickle cell disease, postmenopausal hormone therapy, poor diet, physical inactivity, and obesity and body fat distribution. Less well-documented or potentially modifiable risk factors include the metabolic syndrome, excessive alcohol consumption, drug abuse, use of oral contraceptives, sleep-disordered breathing, migraine, hyperhomocysteinemia, elevated lipoprotein(a), hypercoagulability, inflammation, and infection. Data on the use of aspirin for primary stroke prevention are reviewed.

CONCLUSIONS

Extensive evidence identifies a variety of specific factors that increase the risk of a first stroke and that provide strategies for reducing that risk.

Testing for Inherited Thrombophilias in Arterial Stroke

Background and Purpose— Despite a paucity of evidence supporting a true association of ischemic stroke and the inherited thrombophilias, it is common practice for many neurologists to order these tests as part of the work-up of ischemic stroke, especially in young patients. Treatment with oral anticoagulation is often used in patients with positive results for the inherited thrombophilias.

Methods— We reviewed the literature focusing on case-control studies of the 5 most commonly inherited disorders of coagulation: protein C deficiency, protein S deficiency, antithrombin deficiency, and the factor V Leiden and prothrombin gene mutations in patients with stroke. We also analyzed the available data on stroke patients with inherited thrombophilia and patent foramen ovale.

Results— Multiple case-control studies have not convincingly shown an association of the inherited thrombophilias with ischemic stroke, even in young patients and patients with patent foramen ovale.

Conclusion— If there is an association between the inherited thrombophilias and arterial stroke, then it is a weak one, likely enhanced by other prothrombotic risk factors. The consequences of ordering these tests and attributing causality to an arterial event can result in significant costs to the health care system and pose a potential risk to patients, because this may lead to inappropriate use of long-term oral anticoagulants, exposing patients to harm without a clearly defined benefit.

Guidelines for the prevention of stroke in patients with stroke or transient ischemic attack: a guideline for healthcare professionals from the american heart association/american stroke association

The aim of this updated statement is to provide comprehensive and timely evidence-based recommendations on the prevention of ischemic stroke among survivors of ischemic stroke or transient ischemic attack. Evidence-based recommendations are included for the control of risk factors, interventional approaches for atherosclerotic disease, antithrombotic treatments for cardioembolism, and the use of antiplatelet agents for noncardioembolic stroke. Further recommendations are provided for the prevention of recurrent stroke in a variety of other specific circumstances, including arterial dissections; patent foramen ovale; hyperhomocysteinemia; hypercoagulable states; sickle cell disease; cerebral venous sinus thrombosis; stroke among women, particularly with regard to pregnancy and the use of postmenopausal hormones; the use of anticoagulation after cerebral hemorrhage; and special approaches to the implementation of guidelines and their use in high-risk populations.

Patent foramen ovale in cerebral infarction

Recent studies support the hypothesis of a close aetiological and pathogenic association between the presence of patent foramen ovale (PFO) and cryptogenic stroke. The therapeutic options currently used in the treatment of these patients range from standard antiaggregation and standard-dose anticoagulation to the percutaneous occlusion of the PFO. The use or recommendation of treatment is based both on clinical risk factors associated with PFO, such as age, detection of states of hypercoagulability and previous history of stroke, and on the risks associated to right-to-left shunt (RLSh) and PFO, such as the size of PFO, magnitude of RLSh and the presence of atrial septal aneurysm (ASA). However, there is currently no consensus regarding the most suitable treatment and it is surprising to observe the widespread use of certain therapeutic approaches which are not supported by clinical evidence. In this revision, we analyse the relevance of PFO in cryptogenic stroke, consider the main evidence available for determining the best management of these patients and make diagnostic and therapeutic management recommendations.

Patent foramen ovale and stroke

The presence of a patent foramen ovale has been found to be associated with an increased risk of ischemic stroke of otherwise unknown origin (cryptogenic stroke). The present article will review the evidence regarding this association, the technical aspects of PFO detection, and the preventive options to decrease the risk of recurrent cerebral events.

Prevention strategies for cardioembolic stroke: present and future perspectives

Atrial fibrillation (AF) is the most common cause of cardioembolism. An update on secondary prevention strategies, used to protect patients from the risk of stroke in many common cardiac conditions, is presented in the paper. The main line of actions of stroke prevention in cardioembolism is mostly connected with antithrombotic drugs, but also other, more invasive, techniques are quickly emerging. Also the classic pharmacological prevention with coumarins may soon be overcome by new generation anticoagulants. Is an aggressive treatment of Patent Foramen Ovale (PFO) always recommended? One of the main challenges of the future years will be to understand competitiveness between old and new preventive strategies.

Prevention of Stroke in Patients with Patent Foramen Ovale

Patent foramen ovale is found in 24% of healthy adults and 38% of patients with cryptogenic stroke. This ratio and case reports indicate that patent foramen ovale and stroke are associated, probably because of paradoxical embolism. In healthy people with patent foramen ovale, embolic events are not more frequent than in controls, and therefore no primary prevention is needed. However, once ischaemic events occur, the risk of recurrence is substantial and prevention becomes an issue. Acetylsalicylic acid and warfarin reduce this risk to the same level as in patients without patent foramen ovale. Patent foramen ovale with a coinciding atrial septal aneurysm, spontaneous or large right-to-left shunt, or multiple ischaemic events potentiates the risk of recurrence. Transcatheter device closure has therefore become an intriguing addition to medical treatment, but its therapeutic value still needs to be confirmed by randomised-controlled trials.

Migraine and patent foramen ovale: state of the science

Migraine is a prominent cause of recurrent pain, affecting 12% of the population. In several case series, approximately 50% of migraineurs with aura were found to have patent foramen ovale (PFO). The pathophysiological mechanism is speculated to be passage of microemboli and vasoactive chemicals through the PFO, thereby evading pulmonary filtration and triggering migraine symptoms. This article presents the results of retrospective and prospective research studies documenting the effects of PFO closure on migraine symptoms and presents emerging theories on possible pathologic mechanisms that may partially explain the increased risk of ischemic stroke in the migraine population. Finally, evidence-based recommendations are presented for health care providers for managing patients who have migraine and PFO.

Estudo caso-controle com resposta multinomial: uma proposta de análise

Este estudo revisa alguns artigos com delineamento do tipo caso-controle em que se tem os casos classificados em dois ou mais tipos. A aplicação de modelos para respostas multinomiais e a adequabilidade destes aos estudos caso-controle é discutida. Dentre os ajustes possíveis, argumenta-se que o modelo logístico Politômico é o mais indicado para a obtenção de medidas epidemiológicas de risco e associação neste tipo de delineamento. Como ilustração, apresenta-se uma aplicação desse modelo em um estudo caso-controle de base populacional, comparando os resultados com aqueles obtidos em um ajuste logístico binomial. A abordagem multinomial possibilita investigar, em uma única análise, a ocorrência de associações entre co-variáveis e uma ou algumas das classes de casos estudados, abrindo a possibilidade, de grande interesse epidemiológico, de identificação de fatores de risco e de proteção individualizados para cada subgrupo de interesse.

Patent foramen ovale and stroke: what should be done?

PURPOSE OF REVIEW

The role of a patent foramen ovale (PFO) as a risk factor for ischemic stroke has been established in recent years. However, the best therapeutic option to prevent recurrent events is still controversial, with antithrombotic treatment or transcatheter PFO closure being favored by different clinicians. Also, associated conditions that may guide the therapeutic choices are being investigated.

RECENT FINDINGS

The stroke risk associated with a PFO, mainly considered of importance in younger patients, has also been recognized and better defined in patients over the age of 55 years. The study of potential cofactors that may increase the possibility of paradoxical embolization through the PFO has made some progress and holds promises of allowing more informed and rational treatment choices in the future. More data have become available on the efficacy of transcatheter PFO closure.

SUMMARY

The approach to patients with PFO and ischemic stroke has been better defined in recent years. However, a better understanding of factors that increase the stroke risk in individuals with a PFO and the results from randomized treatment trials comparing medical treatment with PFO closure are needed to further advance the field.

Patent foramen ovale and cryptogenic stroke: a complex neuro-cardio-vascular problem

Patent foramen ovale has been suggested to be a risk factor for cryptogenic stroke by means of paradoxical embolism. The data, however, are complex, conflicting and largely unavailable. In this review, we attempt to summarize the existing data separately for the questions of whether patent foramen ovale is associated with cryptogenic stroke and whether it is a risk factor for a first ischemic stroke and for recurrent strokes. Treatment options will be discussed, and the different viewpoints from the two specialists mainly involved in the care of those complex patients (neurologists and cardiologists) will be provided.

Embolic implications of combined risk factors in patients with patent foramen ovale (the CARPE criteria): consideration for primary prevention closure?

BACKGROUND

Large patent foramen ovale (PFO), spontaneous right-to-left shunt, large atrial septal aneurysm (ASA), coagulation abnormalities, and prominent eustachian valve (EV) have all been independently suggested as risk factors for recurrent stroke. We sought to retrospectively evaluate risk of stroke and impact of transcatheter PFO closure in patients with concurrent large PFO, spontaneous right-to-left shunt, large ASA, coagulation abnormalities, and prominent EV.

METHODS

Between March 2006 and October 2008, 36 (mean age 44 +/- 10.9 years, 28 females) out of 120 consecutive patients referred to our center for transcatheter PFO closure had concomitant diagnosis of (a) large PFO on transcranial Doppler (TCD) and transesophageal echocardiography (TEE), (b) spontaneous right-to-left shunt on TCD, (c) large ASA, (d) prominent EV, and (e) coagulation abnormalities. All patients fulfilled the standard current indications for transcatheter closure and underwent preoperative TEE and brain magnetic resonance imaging (MRI), with subsequent intracardiac echocardiographic-guided transcatheter PFO closure.

RESULTS

Compared to the remaining PFO population in the same period, patients with all five concomitant features had more ischemic brain lesions on MRI, previous history of recurrent stroke, more frequently a history of venous thromboembolism, and more severe migraine with aura. The concomitance of all the features confers the highest risk of recurrent stroke (OR 9.9, 3.0-18 [95% CI], P < 0.001).

CONCLUSIONS

Despite its small sample size and nonrandomized retrospective nature, this is the first study to suggest that patients with concurrence of all the investigated characteristics have potentially a higher risk of stroke compared to controls. We thus propose the CARP criteria as a basis for further larger, longitudinal studies to assess the potential benefits of transcatheter closure in this patient subset in the absence of clinical recurrent stroke.

[Cryptogenic cerebral infarction: from classification to concept]

Since the foundations laid by Sacco and Mohr in 1989, from the Stroke data bank, cryptogenic infarctions have had a predominant place among the causes of ischemic strokes. In that study, they accounted for approximately 40% of the stroke causes. Cryptogenic infarctions are infarctions without a defined cause, despite a complete work-up; they differ from infarctions of undetermined causes, which may involve overlapping causes or an incomplete investigation. The size of this group will probably shrink as knowledge advances. Patent foramen ovale (PFO), with or without a septal aneurysm, is more frequent in patients with a cryptogenic infarction. Transesophageal echocardiography is the reference examination for screening for these abnormalities. A meta-analysis of several case-control studies showed a significant association between PFO and stroke in subjects younger than 55 years. For now, these septal abnormalities constitute a risk factor but not a cause. Complex aortic atheroma affecting area upstream of the left subclavian artery may be a source of cerebral embolisms in some conditions. The prevalence of this disease increases with age. It is identified most frequently in patients older than 60 years with a cryptogenic infarction. The thickness of the atheromatous plaque determines whether it is a risk factor or a cause. Recent stroke classifications do not consider carotid atheromatous lesions less than 50% to be a source of ischemic stroke. Nonetheless some studies identify moderate stenosis of the carotid artery more frequently in infarctions of unknown causes than in other categories. The increased risk of cerebral infarction when parents and homozygous twins have a history of stroke suggests that there may be genetic causes that have not yet been detected. An unknown genetic cause would thus be included in the infarctions of unknown causes. A recent study tested for Fabry disease in young patients with a cryptogenic infarction: 4.9% of the men and 2.4% of the women had a functional mutation of the alpha-galactosidase gene. These findings must be confirmed. Some studies suggest an association between cryptogenic infarction and hereditary thrombophilias. Nonetheless the risk attributable to these thrombophilic disorders is slight and the discovery may be only a coincidence. The work described above shows the importance of stratification in the identification of stroke causes: age older or younger than 55/60 years, type of interatrial abnormality (PFO and aneurysms of the interatrial septum), type of atheroma of the aortic arch (more or less than 4mm). They also show the difficulty involved in attributing cause to an identified abnormality: is carotid stenosis of less than 50% a marker of atherosclerosis or also a cause of stroke? To continue improving our understanding of the mechanisms of strokes, new investigational techniques are under evaluation. They include magnetic resonance imaging (MRI), computed tomographic angiography (CT), positron emission tomography (PET) of carotid plaque and of the aortic arch, transcranial Doppler, cardiac recording by telemetry, and even new biological assays.

Cryptogenic stroke and patent foramen ovale: clinical clues to paradoxical embolism

BACKGROUND

Patent foramen ovale (PFO) is an independent risk factor for cerebral infarction. Since ~25% of the population have a PFO, the simple association of PFO with stroke is not enough to establish the diagnosis of paradoxical embolism. We evaluated possible clinical clues to the diagnosis of paradoxical embolism.

METHODS

Among patients with cryptogenic ischemic stroke (CS) who were investigated for a right-to-left shunt (RLS), we compared clinical, coagulation and biochemical parameters in patients with PFO versus without PFO.

RESULTS

Among 1689 new patients referred for TIA/non-disabling stroke between 2001 and 2007, 175 with cryptogenic stroke (CS) were investigated for RLS by transcranial Doppler (TCD) bubble studies; 89 (5.5%) with positive TCD had a PFO confirmed by TEE. In multivariate logistic regression, a history of DVT or pulmonary embolism (OR, 4.39; 95% CI, 1.23-15.69; p=0.023), prolonged travel (OR, 8.77; 95% CI, 1.775-43.3; p=0.008) , migraine (OR, 2.30: 95% CI, 1.07-4.92; p=0.031), a Valsalva maneuver preceding the onset of focal neurological symptoms (OR, 3.33; 95% CI, 1.15-9.64; p=0.026) and waking up with stroke/TIA (OR, 4.53, 95% CI, 1.26-16.2; p=0.018) were independently associated with PFO-associated cerebrovascular events. Patients with PFO had higher plasma total homocysteine levels than patients without PFO (8.9+/-3 versus 7.9+/-2.6 micromol/L respectively; p=0.021).

CONCLUSIONS

A history of DVT or pulmonary embolism, migraine, recent prolonged travel, sleep apnea, waking up with TIA or stroke or a Valsalva maneuver preceding the event are clinical clues to the diagnosis of paradoxical embolism among patients with CS.

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.

Asymptomatic significant patent foramen ovale: giving patent foramen ovale management back to the cardiologist

Percutaneous closure of patent foramen ovale (PFO) is still a much debated issue. Although many questions remain open, patients are finding out about PFO management and are beginning to ask for the most rapid and complete solution to their potential problems in spite of the warnings from the medical profession about off-label indications for transcatheter closure. As a result, asymptomatic patients with PFO are coming into medical offices to be assured about stroke risk or treated for any degree of migraine. The cardiologist should be the preferred interlocutor in asymptomatic significant PFO: he is competent in assessing the associated anatomical and functional risk factors, and he is the only specialist who can evaluate on the basis of the anatomo-functional picture the potential risk of paradoxical embolism and discuss with patients eventual off-label indications to closure.

Cryptogenic stroke: time to determine aetiology

Strokes that remain without a definite cause even after extensive work-up are classified as cryptogenic. These constitute about 30-40% of all strokes. Stroke aetiology may remain undetermined for the following reasons: (i) the cause of stroke is transitory or reversible and the diagnostic work-out is not therefore performed at the appropriate time; (ii) all known causes of stroke are not fully investigated; (iii) some causes of stroke remain unknown. Recent studies have challenged the previous view that cryptogenic stroke is a relatively benign cerebrovascular event, and have shown that cryptogenic stroke is associated with a higher rate of recurrence and adverse outcome at long-term follow-up. The determination of stroke aetiology is a valuable procedure to avoid the risk of stroke recurrence, especially in young patients. In this review, we discuss new evidence on the aetiology of cryptogenic stroke, specifically focusing on patients with patent foramen ovale and atheroma of the aortic arch.

Advances in the Genetic Basis of Ischemic Stroke

As one of the leading causes of death within both the developed and developing world, stroke is a world-wide problem. About 80% of strokes are ischemic. It is caused by multiple genetic factors, environmental factors, and interactions among these factors. There is a long list of candidate genes that have been studied for a possible association with ischemic stroke. Among the most widely investigated genes are those involved in haemostasis, inflammation, nitric oxide production, homocysteine and lipid metabolism, renin-angiotensin-aldosterone system. Combined link-age/association studies have demonstrated that genes encoding PDE4D and ALOX5AP confer risk for stroke. We review the studies of these genes which may have potential application on the early diagnosis, prevention and treatment ischemic stroke patients.

[Feasibility and results of transcatheter treatment of patent foramen ovale associated with atrial septal aneurysm. Experience of a general hospital in Mulhouse, France]

OBJECTIVE

To evaluate the results and the feasibility of the technique of percutaneous closing of patent foramen oval (PFO) with Atrial Septal Aneurysm (ASA) among young patients having presented a cryptogenic cerebral ischemia.

PATIENTS AND METHODS

Eighteen patients: 14 cryptogenic stroke and 4 TIA with a broad PFO (rank III) and an important ASA (excursion higher than 15 mm) at transesophageal echocardiography (TEE). The average age is 48.2 years: man 61%, women 39%. The patients have little cardiovascular risk factor (0.83/patient) and 38% presented recurrent thromboembolic events. Percutaneous closing is carried out under general anaesthesia with TEE and Amplatzer devices implantation. A control TEE is carried out 6 months after closing.

RESULTS

No complication occurred at the time of the procedures. After 72 hours, one patient presented a major complication: one arteriovenous fistula requiring a surgery. Five patients presented a minor complication: two non complicated femoral hematoma, two atrial arrhytmias and one asymptomatic secondary displacement of the device without need for surgery. Seven-teen patients had TEE at six months: the shunt disappeared for 95% from the patients, no thrombus was found. No recurrent thromboembolic event appeared for the 18 patients (median follow-up 19.2 months).

CONCLUSION

The installation of a technique of percutaneous closing of the PFO+ASA is safe and effective.

Spontaneous large right-to-left shunt and migraine headache with aura are risk factors for recurrent stroke in patients with a patent foramen ovale

BACKGROUND

We sought to determine whether migraine headache with aura (MHA) and spontaneous large right-to-left (R-L) shunt are risk factors for recurrent cerebral ischemic events in cryptogenic stroke patients with a patent foramen ovale (PFO).

METHODS

140 patients with a PFO and cryptogenic stroke underwent transcatheter defect closure at our institution at a mean age of 45+/-13 years. We retrospectively analyzed follow-up data from the first cerebral ischemic event to the time of PFO closure. Before the procedure, all patients underwent transesophageal echocardiography (TEE); Transcranial Doppler scanning (TCD) was additionally performed on the last 59 patients. We analyzed the impact of MHA, thrombophilia, spontaneous large R-L shunt, and atrial septal aneurysm (ASA) on the risk of recurrent cerebral ischemic events.

RESULTS

44 patients (31%) had had at least 1 recurrent event during a follow-up of 2.2+/-2.6 years. Patients with recurrent events were more commonly females (p=0.0001), had more often an associated thrombophilia (p=0.0077), and had a higher prevalence of spontaneously large R-L shunt both at TEE and at TCD (p<0.05). They also had more commonly a history of MHA (p=0.0009) and more frequent episodes of MHA (p=0.0048). Patients with MHA had a higher risk of recurrent events when compared to patients without (odds ratio 3.87, 95% CI 1.75 to 8.50). Thrombophilia (p=0.001) and spontaneous large R-L shunt (p=0.02) were independent predictors of recurrent stroke.

CONCLUSIONS

In cryptogenic stroke patients with a PFO, a history of MHA, large spontaneous large R-L shunt, and thrombophilia are all associated with a higher risk of recurrent events.

Patent foramen ovale and prothrombotic markers in young stroke patients

Patent foramen ovale (PFO) is more frequent in cryptogenic stroke patients than in the general population. The aim of this study was to determine prothrombotic markers regarding PFO in young cryptogenic stroke patients. We prospectively included consecutive cryptogenic stroke patients younger than 55 years. PFO was diagnosed with simultaneous transcranial Doppler and transesophageal echocardiography. We analyzed the following prothrombotic markers: antiphospholipid antibodies (APS), protein C and protein S deficiencies, factor V Leiden FVG1691A, prothrombin gene mutation PTG20210A and coagulation factor XII mutation FXIIC46T. From June 2005 to July 2006 we studied 39 patients, mean age 44.7 +/- 8.6 years, 48.7% men. PFO was detected in 17 patients (43.6%). We found no differences between PFO and non-PFO patients regarding prothrombotic markers: APS (P = 0.851), protein S deficiency (P = 0.851), protein C deficiency (P = 0.249), FVG1691A (P = 0.202), PTG20210A (P = 0.401) or FXIIC46T (P = 0.966). Female gender was the only variable related to prothrombotic markers, independent of PFO (P = 0.001). The only prothrombotic marker related to PFO size (large PFO) was APS (P = 0.043). Large PFO were also related to deep venous thrombosis (P = 0.040) and atrial septal aneurysm (P = 0.010). PFO patients do not present more prothrombotic markers than non-PFO patients, but APS are more frequent in large PFO.

Prothrombotic mutations as risk factors for cryptogenic ischemic cerebrovascular events in young subjects with patent foramen ovale

BACKGROUND AND PURPOSE

Patent foramen ovale (PFO) has been identified as a potential risk factor for cerebrovascular ischemia. Procoagulant mutations may increase the risk and impact the choice of appropriate therapy for secondary prevention. We evaluated the prevalence of the 2 most common genetic risk factors for thromboembolism, factor V Leiden (G1691A) and prothrombin G20210A, in young PFO patients who were referred for percutaneous transcatheter closure of their PFO.

METHODS

Ninety-seven patients (50 men; mean+/-SD age, 40.9+/-10.0 years) with first-ever cerebrovascular events before the age of 55 years and 160 age-matched control subjects (69 men; mean+/-SD age, 40.4+/-10.5 years) were recruited into the study. Factor V Leiden and prothrombin G20210A mutations were detected by using a multiplex allele-specific polymerase chain reaction assay.

RESULTS

The prevalence of subjects carrying at least 1 prothrombotic genotype was significantly higher in the group of PFO patients than in the group of controls (10.3% vs 2.5%; chi(2)=7.2, P=0.008). Two patients (2.1%) versus 1 control subject (0.6%) and 8 cases (8.2%) versus 3 controls (1.9%) were carriers for factor V Leiden and prothrombin G20210A mutations, respectively. After adjustment for other vascular risk factors, the combination of either factor V Leiden or prothrombin G20210A and PFO was associated with a 4.7-fold (95% CI=1.4 to 16.1; P=0.008) increased risk of cerebral ischemia in young patients.

CONCLUSIONS

Our results indicate that prothrombotic mutations are important risk factors for cerebral ischemia in young patients with PFO. Screening for thrombotic mutations should be considered in young patients with PFO-related ischemic events.

Inherited Thrombophilia in Arterial Disease: A Selective Review

Thrombophilia may be defined as an acquired or congenital abnormality of hemostasis predisposing to thrombosis. Because arterial thrombosis is usually linked with classical risk factors such as smoking, hypertension, dyslipidemia, or diabetes, a thrombophilia workup is usually not considered in case of arterial thrombosis. The most accepted inherited hemostatic abnormalities associated with venous thromboembolism are factor V Leiden (FVL) and factor II (FII) G20210A mutations, as well as deficiencies in antithrombin (AT), protein C (PC), and protein S (PS). This review focuses on the link between these abnormalities and arterial thrombosis. Overall, the association between these genetic disorders and the three main arterial complications (myocardial infarction [MI], ischemic stroke [IS], and peripheral arterial disease [PAD]) is modest. Routine screening for these disorders is therefore not warranted in most cases of arterial complications. However, when such an arterial event occurs in a young person, inherited abnormalities of hemostasis seem to play a role, particularly when associated with smoking or oral contraceptive use. These abnormalities also seem to play a role in the risk of premature occlusion after revascularization procedures. Therefore thrombophilia tests may be informative in a very restricted population with arterial events. Anticoagulants rather than antiplatelet therapy may be preferable for these patients, although this remains to be proven.

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

BACKGROUND

Whether use of oral contraceptives is a risk factor for arterial ischaemic stroke is controversial. In particular, few data are available on what criteria should be adopted to establish an individual profile of risk before the start of oral contraceptives.

PATIENTS AND METHODS

The effects of oral contraceptives and their interaction with the G1691A polymorphisms of the factor V gene, the G20210A polymorphisms of the prothrombin gene and the C677T polymorphisms of the MTHFR gene on the risk of cerebral ischaemia were determined in a series of 108 consecutive women aged <45 years with ischaemic stroke and 216 controls, in a hospital-based case-control study design.

RESULTS

Use of oral contraceptives was associated with an increased risk of cerebral ischaemia (odds ratio (OR) 3.95; 95% confidence interval (CI) 2.29 to 6.78). ORs for stroke were 2.25 (95% CI 1.15 to 4.40), 3.94 (95% CI 2.28 to 6.81) and 8.87 (95% CI 3.72 to 21.1) for non-oral contraceptive users with the TT MTHFR genotype, oral contraceptive users without the TT MTHFR genotype and oral contraceptive users with the TT MTHFR genotype, respectively, when compared with non-oral contraceptive users without the TT MTHFR genotype, with a multiplicative independent effect. Compared with non-oral contraceptive users, ORs for stroke were 2.65 (95% CI 1.46 to 4.81) for oral contraceptive users with none of the studied polymorphisms and 22.8 (95% CI 4.46 to 116.00) for oral contraceptive users with at least one of the studied polymorphisms, with a synergistic effect.

CONCLUSIONS

Exposure to the effects of oral contraceptives may increase the risk of ischaemic stroke in women with an inherited prothrombotic background. Testing for these genetic variants may allow more accurate stratification of the population at risk before long-term use of oral contraceptives is prescribed.

Patent Foramen Ovale and the Risk of Ischemic Stroke in a Multiethnic Population

OBJECTIVES

We sought to assess the risk of ischemic stroke from a patent foramen ovale (PFO) in the multiethnic prospective cohort of northern Manhattan.

BACKGROUND

Patent foramen ovale has been associated with increased risk of ischemic stroke, mainly in case-control studies. The actual PFO-related stroke risk in the general population is unclear.

METHODS

The presence of PFO was assessed at baseline by using transthoracic 2-dimensional echocardiography with contrast injection in 1,100 stroke-free subjects older than 39 years of age (mean age 68.7 +/- 10.0 years) from the Northern Manhattan Study (NOMAS). The presence of atrial septal aneurysm (ASA) also was recorded. Subjects were followed annually for outcomes. We assessed PFO/ASA-related stroke risk after adjusting for established stroke risk factors.

RESULTS

We detected PFO in 164 subjects (14.9%); ASA was present in 27 subjects (2.5%) and associated with PFO in 19 subjects. During a mean follow-up of 79.7 +/- 28.0 months, an ischemic stroke occurred in 68 subjects (6.2%). After adjustment for demographics and risk factors, PFO was not found to be significantly associated with stroke (hazard ratio 1.64, 95% confidence interval [CI] 0.87 to 3.09). The same trend was observed in all age, gender, and race-ethnic subgroups. The coexistence of PFO and ASA did not increase the stroke risk (adjusted hazard ratio 1.25, 95% CI 0.17 to 9.24). Isolated ASA was associated with elevated stroke incidence (2 of 8, or 25%; adjusted hazard ratio 3.66, 95% CI 0.88 to 15.30).

CONCLUSIONS

Patent foramen ovale, alone or together with ASA, was not associated with an increased stroke risk in this multiethnic cohort. The independent role of ASA needs further assessment in appositely designed and powered studies.

Interaction of homocysteine and conventional predisposing factors on risk of ischaemic stroke in young people: consistency in phenotype-disease analysis and genotype-disease analysis

BACKGROUND AND OBJECTIVES

Whether the association between mild hyperhomocysteinaemia and ischaemic stroke is the consequence of a predisposing genetic background or is due to the confounding influence of established predisposing factors remains to be determined.

METHODS

Plasma total homocysteine (tHcy) concentration and the distribution of the C677T genotypes of the methylenetetrahydrofolate reductase gene (MTHFR) were compared in 174 consecutive patients with stroke aged <45 years and 155 age and sex-matched controls. The effect of conventional risk factors on the relationship between phenotype-disease and genotype-disease was analysed by two-way and three-way interaction analysis and by the classification and regression trees (CART) model.

RESULTS

tHcy concentrations were markedly higher in patients with ischaemic stroke (median 11.9 micromol/l, range 2.0-94.0) than in controls (median 9.8 micromol/l, range 4.7-49.6). An increased risk was also associated with the TT677 genotype (odds ratio (OR) 1.98; 95% confidence interval (CI) 1.04 to 3.78) and with the T allele (1.40; 95% 1.03 to 1.92) of the MTHFR gene. A differential effect of Hcy levels on risk of stroke was observed according to the distribution of environmental-behavioural risk factors, with a stronger influence in the subcategory of people with hypertension and smokers (OR 24.8; 95% CI 3.15 to 196). A comparable environmental-dependent TT677 MTHFR genotype-stroke association was observed in the genotype-disease analysis.

CONCLUSIONS

A consistency of phenotype-disease analysis and genotype-disease analysis is indicated by analysing specific subcategories of patients, defined by the distribution of established risk factors. The assumption that the Hcy-stroke relationship is unlikely due to a reverse-causality bias is indirectly supported by our data.

Patent foramen ovale and cerebrovascular diseases

Patent foramen ovale (PFO) has been linked to ischemic strokes of undetermined cause (cryptogenic strokes). PFO-a remnant of fetal circulation when the foramen ovale does not seal after birth-can permit microemboli to escape the pulmonary filter into the intracranial circulation, causing stroke. Coexistent atrial septal aneurysm, pelvic deep vein thrombosis and inherited clotting factor deficiencies could potentiate stroke risk in patients with PFO. Transcatheter PFO closure, a minimally invasive procedure, is one technique used to prevent recurrent cerebrovascular events. A connection between PFO and migraine headache has been conceptualized from retrospective evidence of reduced migraine frequency and severity after PFO closure; however, prospective randomized trials are needed to verify the efficacy of PFO closure on migraine prevention. In this review we discuss embryologic origins, diagnostic techniques and treatment options for prevention of paradoxical embolism thought to be related to PFO, and the relation of PFO to cryptogenic stroke and migraine.

Advancing the study of stroke in women: summary and recommendations for future research from an NINDS-Sponsored Multidisciplinary Working Group

BACKGROUND AND PURPOSE

Women have poorer outcomes from stroke than men. Women also have risk factors that are unique, including pregnancy and hormone therapy. Hormone therapy for postmenopausal replacement increased the risk of ischemic stroke according to results of the Women's Health Initiative clinical trials. Based on the current understanding of the mechanisms of action of estrogen, the reasons for this increased risk are uncertain. One method to better understand the reasons for this increased risk is to re-evaluate estrogen's role in the neurovascular unit, simplistically comprised of the neurons, glia, and endothelial cells, as well as the processes of inflammation, and hemostasis/thrombosis. Besides the role of estrogen there are many gaps of knowledge about issues specific to women and stroke.

SUMMARY OF REVIEW

A multidisciplinary workshop was held in August 2005 to summarize the current evidence for estrogen and, more generally, stroke in women, and to provide recommendations for future basic, preclinical, and clinical research studies.

CONCLUSIONS

These studies may ultimately change the approach to stroke prevention and treatment in women.

[Clinical relevance of patent foramen ovale and right-to-left shunt]

A frequent finding in healthy individuals, patent foramen ovale (PFO) with right-to-left shunt (RLSh), is an embrionary residue that has been linked with cryptogenic stroke and peripheral ischemia. Pulmonary hypertension and entities like decompression illness, migraine with aura or plathypnea-orthodeoxia have been found to have a higher prevalence of PFO with RLSh. Some dementias and unexplained syncopes could also have some relationship. Paradoxical embolism, thrombosis of the foramen channel or the atrial structures with subsequent embolism, transient arrhythmias, prothrombotic states and vasoactive substances passage have been proposed as physiopathologic mechanisms involved. Contrast-enhanced transesophageal echocardiography is the standard reference diagnostic procedure but contrast-enhanced transcranial Doppler is a good non-invasive alternative diagnostic tool that is highly sensitive and specific.

Primary Prevention of Ischemic Stroke

Background and Purpose— This guideline provides an overview of the evidence on various established and potential stroke risk factors and provides recommendations for the reduction of stroke risk.

Methods— Writing group members were nominated by the committee chair on the basis of each writer’s previous work in relevant topic areas and were approved by the American Heart Association Stroke Council’s Scientific Statement Oversight Committee. The writers used systematic literature reviews (covering the time period since the last review published in 2001 up to January 2005), reference to previously published guidelines, personal files, and expert opinion to summarize existing evidence, indicate gaps in current knowledge, and when appropriate, formulate recommendations based on standard American Heart Association criteria. All members of the writing group had numerous opportunities to comment in writing on the recommendations and approved the final version of this document. The guideline underwent extensive peer review before consideration and approval by the AHA Science Advisory and Coordinating Committee.

Results— Schemes for assessing a person’s risk of a first stroke were evaluated. Risk factors or risk markers for a first stroke were classified according to their potential for modification (nonmodifiable, modifiable, or potentially modifiable) and strength of evidence (well documented or less well documented). Nonmodifiable risk factors include age, sex, low birth weight, race/ethnicity, and genetic factors. Well-documented and modifiable risk factors include hypertension, exposure to cigarette smoke, diabetes, atrial fibrillation and certain other cardiac conditions, dyslipidemia, carotid artery stenosis, sickle cell disease, postmenopausal hormone therapy, poor diet, physical inactivity, and obesity and body fat distribution. Less well-documented or potentially modifiable risk factors include the metabolic syndrome, alcohol abuse, drug abuse, oral contraceptive use, sleep-disordered breathing, migraine headache, hyperhomocysteinemia, elevated lipoprotein(a), elevated lipoprotein-associated phospholipase, hypercoagulability, inflammation, and infection. Data on the use of aspirin for primary stroke prevention are reviewed.

Conclusion— Extensive evidence is available identifying a variety of specific factors that increase the risk of a first stroke and providing strategies for reducing that risk.

Mutations and polymorphisms in genes affecting hemostasis proteins and homocysteine metabolism in children with arterial ischemic stroke

BACKGROUND

The pathogenesis of thrombosis in childhood seems to be multifactorial implicating genetic and environmental factors.

AIM

To compare the distributions of mutations/polymorphisms in genes affecting hemostasis (factor V Leiden - FVL, FV H1298R-FVR2, FII 20210A, b-Fib 455G>A, FXIII V34L, PAI-1 4G, HPA-1b) or homocysteine metabolism (MTHFR C677T, MTHFR A1298C) among 90 children with arterial ischemic stroke (AIS) and 103 controls, and to associate the carriage of these mutations/polymorphisms with their corresponding proteins in children with AIS.

RESULTS

AIS was more frequent in boys (p < 0.01). No studied mutation/polymorphism was found to be a risk factor for AIS, except for FVL [odds ratio 4.2 (95% CI 1.5-12.1)], the presence of which was even higher in 31 children with congenital AIS [odds ratio 6.82 (95% CI 2.0-22.8)]. FVL carriers had an odds ratio of 5.76 (95% CI 1.6-6.4) when FVR2 was absent. In thrombosed children, activated protein C resistance, prothrombin and fibrinogen levels were higher in the presence of FVL, FII20210A or b-Fib 455G-->A, respectively. Double heterozygotes in both MTHFR C677T and A1298T or homozygotes in one had significantly elevated homocysteine levels.

CONCLUSION

Except for FVL, no definite conclusion could be reached regarding the involvement of the studied mutations/polymorphisms in childhood AIS.

Guidelines for Prevention of Stroke in Patients With Ischemic Stroke or Transient Ischemic Attack

The aim of this new statement is to provide comprehensive and timely evidence-based recommendations on the prevention of ischemic stroke among survivors of ischemic stroke or transient ischemic attack. Evidence-based recommendations are included for the control of risk factors, interventional approaches for atherosclerotic disease, antithrombotic treatments for cardioembolism, and the use of antiplatelet agents for noncardioembolic stroke. Further recommendations are provided for the prevention of recurrent stroke in a variety of other specific circumstances, including arterial dissections; patent foramen ovale; hyperhomocysteinemia; hypercoagulable states; sickle cell disease; cerebral venous sinus thrombosis; stroke among women, particularly with regard to pregnancy and the use of postmenopausal hormones; the use of anticoagulation after cerebral hemorrhage; and special approaches for the implementation of guidelines and their use in high-risk populations.

Transcatheter closure of patent foramen ovale in older adults

OBJECTIVES

Comparing results of patent foramen ovale (PFO) closure in older and younger patient cohorts.

BACKGROUND

The literature pertaining to stroke and PFO has focused on patients <55 years of age.

METHODS

Between March 2000 and December 2003, 456 consecutive stroke/transient ischemic attack (TIA) patients (14.2-91.1 years, mean 51.4 +/- 15.5) underwent successful closure of PFO with a CardioSEAL Septal Occluder by one operator at five hospitals. Of the 456 patients, 184 (40.4%) were >55 years of age at the time of the procedure (mean 66.9 +/- 8.3 years) and comprise the subject group (OLDER). The remaining 272 patients (mean 41.1 +/- 7.7) comprise the control group (YOUNGER). Data were collected prospectively in a registry type format.

RESULTS

Minor procedural complications were comparable: 7/184 (3.8%) OLDER vs. 12/272 (4.4%) YOUNGER (P = NS). In the follow-up period (1-45 months, mean = 17.8 +/- 11.1), there was no significant difference in the rate of recurrent stroke/TIA, headaches, or late unrelated death. Forty OLDER patients and 47 YOUNGER developed new onset atrial arrhythmia (P = NS). The incidence of new onset atrial fibrillation (AF), however, was significantly higher in OLDER (14/40 OLDER and only 2/47 YOUNGER, P < 0.025). All patients who were in normal sinus rhythm (NSR) before the procedure are in NSR at last follow-up.

CONCLUSIONS

Older patients should not be excluded from PFO closure. The procedure seems as safe and effective in preventing recurrent stroke in the older, as in the younger population. Older patients seem more prone to developing AF.

Patent Foramen Ovale and Stroke: Prognosis and Treatment in Young Adults

A patent foramen ovale (PFO) is found with increased frequency in patients with stroke of undetermined origin but the significance and therapeutic implications of this observation remain unclear. Several lines of evidence suggest a role for the PFO in stroke pathophysiology for some cryptogenic stroke patients, such as those whose PFO is accompanied by a prothrombotic state, atrial septal aneurysm, or lower extremity/pelvic DVT. Diagnostic evaluation of the patient with cryptogenic stroke and PFO is directed at identifying these subgroups. Appropriate therapy for primary and secondary stroke prevention in a subject with a PFO remains unclear given current uncertainties as to the pathophysiological significance of PFO. Additional studies are needed, such as those focused on lower extremity veins or the cardiac interatrial septum, to guide therapy in specific stroke subpopulations.

Stroke and pulmonary thromboembolism after a long flight

In the economy class syndrome (ECS) the patient presents a deep venous thrombosis (DVT) with or without pulmonary thromboembolism (PTE) during or after a long trip as a result of prolonged immobilization. Economy class stroke syndrome is an infrequent ECS variant in which ischemic stroke is associated with a patent foramen ovale (PFO). Few cases have been published in the literature to date. We present a patient who suffered a PTE and an ischemic stroke immediately after a transoceanic flight. A 36-year-old woman with no significant medical or familial history flew economy class from Lima, Peru, to Madrid, Spain. On disembarkation she presented sudden dyspnea and a depressed level of consciousness, global aphasia, and right hemiparesis. A pulmonary scintigraphy showed a PTE and a cranial MRI revealed an ischemic infarct in the left middle cerebral artery territory. We simultaneously performed a transesophageal echocardiography and a transcranial Doppler and observed a massive right-to-left shunt through a PFO. The patient was a heterozygous carrier of the C46T mutation of coagulation factor XII. The appearance of a stroke following a long trip is suggestive of paradoxical embolism through a PFO, mainly if it is associated with a DVT and/or a PTE. The cause of the initial event, the DVT, could be a prothrombotic state.

Hypercoagulable states and stroke: a selective review

Blood disorders have been implicated in approximately 5% to 10% of ischemic stroke, with an increased frequency in younger patients. Most disorders are associated with an increased thrombotic tendency and, therefore, an increased risk of ischemic stroke. Less commonly, a bleeding diathesis may predispose a patient to intracranial hemorrhage. While many conditions predisposing to thrombosis have been associated with stroke, there are relatively few prospective, epidemiological studies addressing hypercoagulable states and arterial stroke compared with the number of studies on the genetic thrombophilias, which are predominantly associated with venous thrombosis. When ordering tests of coagulation in stroke patients, one should keep in mind whether the results will influence therapy and/or patient outcome. It is generally not advocated to screen all stroke patients for a "hypercoagulable workup". Typically, patients to be screened for coagulation defects will have a prior history of one or more unexplained thromboembolic events. The yield for diagnosing a hypercoagulable state is typically greatest for young stroke patients or those with a family history of thrombosis and who have no other explanations for their stroke (cryptogenic stroke). The yield in typically low in unselected ischemic stroke patients and older patients. Treatment of a first stroke with a documented hypercoagulable state is typically long-term or indefinite duration warfarin, although there is a paucity of clinical trial data supporting this clinical approach.

Dose-Related Association of MTHFR 677T Allele With Risk of Ischemic Stroke

Background— Data are conflicting concerning ischemic stroke risk associated with a common polymorphism in the gene encoding 5,10-methylenetetrahydrofolate reductase ( MTHFR 677C→T), which predisposes to hyperhomocystinemia in vivo.

Methods— We performed a systematic review and meta-analysis of published relevant literature. We included cohort, case-control, or cross-sectional studies reporting the frequencies of heterozygous (CT) and homozygous (TT) genotypes in (a) all stroke/TIA (overall group) and (b) imaging-proven ischemic stroke (best-phenotyped group).

Results— Among 14 870 subjects, the pooled estimated risk of stroke/TIA associated with the 677T allele increased in a dose-dependent manner (T allele pooled OR 1.17, 95%CI 1.09 to 1.26, TT genotype pooled OR 1.37, 95%CI 1.15 to 1.64). An almost-identical relationship was observed when the analysis was restricted to imaging-proven ischemic stroke (T allele pooled OR 1.18, 95%CI 1.09 to 1.29, TT genotype pooled OR 1.48, 95%CI 1.22 to 1.8).

Conclusion— A graded increase in ischemic stroke risk with increasing MTHFR 677T allele dose was observed, suggesting an influence of this polymorphism as a genetic stroke risk factor and supporting other evidence indicating a causal relationship between elevated homocysteine and stroke.

Patent foramen ovale: The never-ending story

Several uncontrolled studies suggested a relationship between patent foramen ovale (PFO) and stroke. But recent data indicate that previous studies may overestimate the association between PFO and stroke. First, among patients who have had a cryptogenic stroke under treatment (with either warfarin or aspirin), the main data from the French PFO/atrial septal aneurysm (ASA) and PICSS (Patent Foramen Ovale in Cryptogenic Stroke Study), analyzed separately and in combination, indicate that PFO alone does not announce a significantly increased risk of recurrent stroke or death. But a small increase or decrease in risk cannot be excluded by this meta-analysis. Second, the data concerning the association between PFO and ASA are not clear and variable: the French PFO/ASA study found a significantly increased risk of recurrent stroke in patients with cryptogenic stroke and an association between PFO and ASA when treated medically. In contrast, PICSS found no association between the combined PFO-ASA with stroke or death, but the two populations had meaningful differences. Patients in the PICSS were much older than those in the French PFO/ASA study and had more risk factors for stroke, such as hypertension, diabetes, and history of prior stroke. Third, there were inadequate data to conclude about ASA alone. Possible practice recommendations could come from this meta-analysis: the evidence indicates that the risk of recurrent stroke or death is not different for patients with a PFO who underwent cryptogenic stroke compared to patients without a PFO who underwent a cryptogenic stroke under treatment with either aspirin or warfarin. But aspirin is more preferable (300 mg/d). However, it seems that the association between PFO and ASA confers an increased risk of recurrent stroke in medically treated patients who are less than 55 years of age. This subgroup of younger stroke patients may benefit from other treatments, such as the percutaneous closure of PFO or mini-invasive surgery to a lesser extent, but their efficacy and safety are not yet assessed by large randomized trials. However, we must also keep in mind that some stroke patients with PFO are psychologically attached to their PFO and prefer to close it.