Antiphospholipid antibodies in the acute phase of cerebral ischaemia in young adults: a descriptive study of 139 patients

Ten-year follow-up investigation of stroke risk in systemic lupus erythematosus

BACKGROUND AND PURPOSE

To analyse the long-term risk of ischaemic stroke and the clinical effects of antithrombotics on the risk of haemorrhagic stroke in patients with systemic lupus erythematosus (SLE).

METHODS

A retrospective cohort study was conducted using a population-based database taken from Taiwan National Health Insurance Research Database. Patients with SLE between 2000 and 2008 were registered and matched with two controls by the index date, age, gender and Charlson Comorbidity Index (CCI). These subjects were followed until either stroke event or 31 December 2013. Adjusted HRs (aHRs) for strokes were estimated with Cox regression models, and the cumulative incidence of ischaemic stroke was analysed by log-rank test and Kaplan-Meier survival analysis.

RESULTS

In total, 8310 patients with SLE and 16 620 patients without SLE were included. In general, patients with SLE had higher rates of ischaemic stroke (5.4% vs 3.3%) and haemorrhagic stroke (1.5% vs 0.6%) than in controls. In multivariate analysis adjusted to age, gender, CCI, urbanisation level and antithrombotics uses, aHRs of all strokes, ischaemic stroke and haemorrhagic stroke were 1.73 (95% CI: 1.54 to 1.94), 1.65 (95% CI: 1.45 to 1.87) and 2.24 (95% CI: 1.71 to 2.95), respectively, in patients with SLE. Patients with SLE were significantly more likely to suffer ischaemic stroke than patients without SLE, even 10 years after SLE diagnosis (6.12% vs 3.50%, p<0.001). Antiplatelet use increased the risk of haemorrhagic stroke in SLE group (aHR=1.74, 95% CI: 1.18 to 2.57).

CONCLUSIONS

Patients with SLE are at greater risk of developing ischaemic stroke that lasts for 10 years. Antiplatelets should be carefully administered to prevent cardiovascular events in patients with SLE due to the risk of haemorrhagic stroke.

Was Antiphospholipid Syndrome a Risk Factor of Stroke? A Systemic Review and Meta-Analysis of Cohort Studies

Antiphospholipid syndrome (APS) is characterized by thrombosis. This systemic review and meta-analysis was to verify the hypothesis that APS might increase the risk of stroke. Studies were identified after literature searching of PubMed, Embase, and Cochrane. Newcastle-Ottawa Quality Assessment Scale Cohort Studies (NOQAS-C) was used to assess the quality of studies. The pooled effect with 95% confidence interval (95% CI) was calculated by random-effect model. I-square (I²) was used to test heterogeneity. Funnel plot was used to evaluate publication bias. A total of 17 cohort studies with overall high quality were included. There was no publication bias. Pooled hazard ratio of stroke occurrence in APS patients was 1.76 (1.39-2.21) with low heterogenicity and stable result from sensitivity analysis. In the analysis of subgroups, pooled risk ratios of stroke occurrence in patients with only positive antibodies of APS diagnosis were 1.75 (0.99-3.09), which for the APS patients with other autoimmune diseases were 14.70 (7.56-28.56). APS might be a risk factor of stroke, especially in patients with other autoimmune diseases.

Rheumatic diseases and autoimmune vascular dementia

Vascular dementia (VD) comes second after Alzheimer's disease (AD) as a cause of impaired cognition. VD is not a specific nosological entity, but rather a syndrome encompassing a number of diseases caused by impaired supply of blood to the brain. Systemic autoimmune disorders such as systemic lupus erythematosus, rheumatoid arthritis, vasculitis and antiphospholipid syndrome (APS) can be associated with dementia. VD is often related to the presence of traditional cardiovascular risk factors, but it may also be associated with a host of disorders affecting the brain blood vessels, neuronal cells, or both. It is important to entertain in the differential diagnosis of VD, to recognize and to cure them accurately in order to preserve life's quality of our patients.

Increased Risk of Dementia in Patients With Systemic Lupus Erythematosus: A Nationwide Population-Based Cohort Study

OBJECTIVE

Systemic lupus erythematosus (SLE) is a systemic autoimmune disorder characterized by varied clinical symptoms and can be comorbid with neuropsychiatric disorders. However, the association between SLE and dementia risk in patients with SLE remains unclear. In this study, we evaluated the incidence of dementia in patients with SLE.

METHODS

Patients were recruited from a nationwide cohort in 2004-2008 and categorized as SLE (n = 1,074; patients diagnosed with SLE) or non-SLE (n = 5,370; age- and sex-matched controls). Each patient was followed for up to 7 years, until either receiving a diagnosis of dementia or until December 31, 2010. Data were analyzed using the Kaplan-Meier method and Cox regression analysis.

RESULTS

The incidence rate of dementia was higher in the SLE cohort (357 per 100,000 person-years) than in the non-SLE cohort (180 per 100,000 person-years). Patients with SLE had a higher risk of dementia than did those without SLE (crude hazard ratio [HR] 1.92; P < 0.05). Cox regression analysis revealed an adjusted HR for dementia in the SLE cohort of 2.14 (P < 0.001), after adjustment for other comorbid diseases and variables.

CONCLUSION

Patients with SLE have a higher risk of dementia.

IgG/IgM antiphospholipid antibodies present in the classification criteria for the antiphospholipid syndrome: a critical review of their association with thrombosis

Essentials The clinical value of IgM antibodies in thrombotic antiphospholipid syndrome (APS) is debated. By review of literature, we reconsidered the clinical value of IgM antibodies in thrombotic APS. More significant correlations with thrombosis were found for the IgG compared to IgM isotype. Unavailability of paired IgG/IgM results hampers evaluating the added value of IgM positivity. Click to hear Dr de Groot's perspective on antiphospholipid syndrome

SUMMARY

Background Despite the update of the classification criteria for the antiphospholipid syndrome (APS), difficulties persist in the identification of patients at risk for thrombosis. Current guidelines include assays detecting IgG/IgM anti-β2 -glycoprotein I and anti-cardiolipin antibodies, although the relevance of IgM antibodies has been debated. Objectives Through a review of the literature from 2001 to 2014, we aimed to formally establish the thrombotic risk stratification potential of IgM as compared with IgG anti-phospholipid antibodies (aPLs). Patients/methods One thousand two hundred and twenty-eight articles were selected by a computer-assisted search of the literature. Of the 177 studies that met our inclusion criteria, the clinical value of IgG/IgM aPLs was established through analysis of odds ratios for thrombosis or percentage of positives in the thrombotic population. Results/conclusions We clearly found more significant correlations with thrombosis for the IgG than for the IgM isotype. Nonetheless, in a minority of studies, significant associations with thrombosis were found for IgM but not IgG antibodies. The unavailability of paired results of IgG and IgM for each separate patient hampers evaluation of the added value of isolated IgM positivity. To fully take advantage of results obtained by future studies, we strongly encourage scientists to provide all studied information per patient. We planned a large multicenter study to investigate clinical associations of isolated/combined positivity for criteria/non-criteria aPLs. Importantly, because of the presence of non-pathogenic aPLs, quantitative assays are characterized by a high false-positivity rate. Optimization of functional assays, such as thrombin generation measuring the whole scheme of coagulation, may help to reduce APS-related morbidity and mortality.

Ischemic stroke in the young: Current perspectives on incidence, risk factors, and cardiovascular prognosis

About one-fourth of ischemic strokes occur in working-aged individuals in the high-income countries, with worldwide increasing incidence in this age group from 1980s to present. Recent evidence suggests that traditional vascular risk factors are more prevalent than previously suggested in young adult stroke patients and they accumulate with age particularly in men. Accordingly, relatively high rates of atherosclerotic changes have been detected in these patients. The strength of association of vascular risk factors has gone poorly studied, however. Many young patients with ischemic stroke have, in turn, no traditional risk factors, while they may harbor other conditions with weak or uncertain association with the stroke alone. These individual conditions often represent a risk factor that may be strictly young-age specific, more prevalent in younger than older stroke patients (e.g. patent foramen ovale), or more prevalent among the young in the population. Despite high rates of vascular risk factors and atherosclerotic changes, these findings do not translate to higher frequencies of identified classical stroke mechanisms. In fact, cryptogenic causes are markedly common and even more frequent among the very young patients. Limited randomized trial evidence exists to support secondary prevention decision-making in patients, yet they face an increased risk of death and future vascular events for years to come-dependent on risk factor profile and cause of the stroke. This review provides an overview of recent data on epidemiology, risk factors, and their strength of association in ischemic stroke in the young. Furthermore, the relationship between with the risk factors and cardiovascular outcomes and key features on the evidence related to secondary prevention will be discussed.

Antiphospholipid Antibodies and Recurrent Thrombotic Events: Persistence and Portfolio

BACKGROUND

There are very limited prospective data on the significance of persistent antiphospholipid antibodies (aPL) and recurrent thrombo-occlusive events (TOEs). We investigated the prognostic value of (1) 2 newer aPL assays, (2) an aPL portfolio and (3) persistent aPL positivity following stroke.

METHODS

A total of 1,770 subjects from the APASS-WARSS study underwent further aPL testing for antibodies to phosphatidylserine (aPS) and anti-β2-glycoprotein-I (anti-β2GPI) from stored sera. Follow-up aPL status was also tested in a subset of subjects. Primary analysis was based on time to any TOE (ischemic stroke, myocardial infarction, transient ischemic attack, deep vein thrombosis, pulmonary embolism or systemic arterial occlusion)/death at 2 years. Cox proportional hazard analyses assessed whether aPL independently related to outcome.

RESULTS

Persistent anti-β2GPI decreased the time to TOE/death after adjustment for potential confounders (hazards ratio (HR) 2.86, 95% CI 1.21-6.76, p = 0.017). When persistent anti-β2GPI was combined with another persistently positive aPL, time to TOE/death was also reduced (HR 3.79, 95% CI 1.18-12.14, p = 0.025). Neither persistent anticardiolipin antibodies nor persistent aPS alone nor a single positive anti-β2GPI nor aPS was associated with decreased time to TOE/death. No single positive aPL, portfolio of baseline aPL or any persistent aPL increased the rate of TOE/death.

CONCLUSIONS

Rates of TOE/death were not influenced by aPL results at baseline or follow-up. Persistent anti-β2GPI alone, and with persistent second aPL, was independently associated with decreased time to TOE/death. Persistent aPL, an aPL portfolio and newer aPL in ischemic stroke patients are not helpful in predicting an increased rate of recurrent TOEs.

The estimated frequency of antiphospholipid antibodies in young adults with cerebrovascular events: a systematic review

BACKGROUND

Around 10% of all thrombotic cerebrovascular events (CVE) occur in young population and in a large proportion of those the trigger remains undetermined. Antiphospholipid antibodies (aPL) are recognised risk factors for ischaemic stroke and recurrent thrombotic events; however, the frequency of aPL in young people with CVE is still an unresolved issue.

OBJECTIVES

To estimate the frequency of aPL in young adults with CVE and to determine whether aPL-positive young individuals are at greater risk of CVE when compared with individuals without aPL by systematically reviewing the literature.

METHODS

Medline reports published between 1970 and 2013 investigating the presence of aPL in young patients (<50 years old) with CVE were included. The median frequency for positive aPL, including lupus anticoagulant, anticardiolipin antibodies (aCL) and antibodies against β2Glycoprotein I (anti-β2GPI), was calculated for stroke and transient ischaemic attacks.

FINDINGS

This systematic review is based on available data from 5217 patients and controls from 43 studies analysing the frequency of aPL in young patients with CVE. The overall aPL frequency was estimated as 17.4% (range 5%-56%) for any CVE, 17.2% (range 2%-56%) for stroke and 11.7% (range 2%-45%) for transient ischaemic attack (TIA). The presence of aPL increased the risk for CVE by 5.48-fold (95% CI 4.42 to 6.79). Based on available data, the frequency of aPL in young patients with CVE can be estimated at 17%, rising up to 22% for aCL in patients with stroke. The presence of aPL seems to confer a fivefold higher risk for stroke or TIA when compared with controls. However, variability in test reproducibility and cut-off definition still represent an important methodological limitation for the current diagnostic testing for aPL. These observations should be confirmed by appropriately designed population studies.

Risk of stroke in patients with rheumatism: a nationwide longitudinal population-based study

The aim of this study was to investigate rheumatoid arthritis (RA), and systemic lupus erythematous (SLE) as risk factors for stroke. The study was analyzed by Using the Taiwan Longitudinal Health Insurance Database 2005 (LHID2005), this cohort study investigated patients with a recorded diagnosis of RA (N = 6114), and SLE (N = 621) between January 1, 2004, and December 31, 2007, with age-matched controls (1:4) (for RA, N = 24456; SLE, N = 2484). We used Cox proportional-hazard regressions to evaluate the hazard ratios (HRs) after adjusting confounding factors. Our study found 383 of 6114 RA patients, experienced stroke during the 20267 person-year follow-up period. The adjusted HR of stroke for RA patients was 1.24 (95% CI, 1.11 to 1.39), and for SLE patients was 1.88 (95% CI, 1.08 to 3.27). When steroid was added as additional confounding factor, the adjusted HR of ischemic stroke for RA patients was 1.32 (95% CI, 1.15 to 1.50), and for SLE patients was 1.31 (95% CI, 0.51 to 3.34). In conclusion, the rheumatic diseases of RA, and SLE are all risk factors for stroke. After controlled the effect of steroid prescription, RA is risk factor for ischemic stroke.

Increased risk of ischemic stroke in patients with systemic lupus erythematosus: a nationwide population-based study

BACKGROUND

Systemic lupus erythematosus (SLE) has been reported to be associated with an increased risk of cardiovascular disease. However, most studies have been criticized for either a small sample size or the lack of a prospective control. Our study investigated the relationship of SLE and the subsequent development of ischemic stroke using a nationwide, population-based database in an Asian population.

METHODS

From 2000 to 2007, we identified a study cohort consisting of a total of 11,637 newly diagnosed SLE patients using the National Health Insurance Research Database in Taiwan. A control cohort of 58,185 subjects without SLE, matched for age, gender, and comorbidities were selected for comparison to observe the occurrence of ischemic stroke in these two groups.

RESULTS

During a follow-up period of up to 7 years, ischemic stroke developed in 258 (2.22%) of the patients with SLE and in 873 (1.5%) of patients in the comparison cohort. Kaplan-Meier analysis also revealed a tendency of SLE patients toward ischemic stroke development (log rank test, p = 0.001). After Cox model adjustment for patients' demographic characteristics and selected comorbidities, patients with SLE were found to have a 1.67-fold (95% CI, 1.45 to 1.91) higher risk of developing ischemic stroke.

CONCLUSION

Patients with SLE have an increased risk of stroke.

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.

Mitral valve prolapse in young healthy individuals. An early index of autoimmunity?

Mitral valve prolapse (MVP) is a benign valvular abnormality. However, an increased prevalence of MVP is reported in patients with systemic lupus erythematosus and autoimmune thyroid disease. Our aim was to evaluate whether the presence of MVP in healthy individuals might indicate a premature index of subclinical autoimmune disorder. A total of 75 individuals with MVP and 44 individuals without MVP were identified by echocardiography. Serum samples were examined for various organ and non-organ specific autoantibodies. In all, 35 of the 75 individuals with MVP had at least one autoantibody. ANA were detected in 17/75 in MVP(+) versus 1/44 in the MVP(-), (P < 0.05), and anti-ENA in 6/75 in the MVP(+) versus 0/44 in the control group, P = ns. In the MVP(+) group, thyroid autoantibodies, IgA and IgG RF were found at a statistically significant higher incidence, 16/75, 11/75 and 10/75 versus 1/44, 0/44 and 0/44 in the MVP(-)group, respectively (P < 0.05). The levels of IgG anticardiolipin antibodies were significantly higher in the MVP(+) group, P < 0.05. The presence of organ and non-organ specific autoantibodies in young healthy MVP(+) individuals insinuate the presence of subclinical autoimmunity and might suggest that autoimmune mechanisms might be involved in its pathogenesis. A follow-up of these individuals might elucidate whether MVP constitutes an early index of autoimmunity.

Prothrombotic risk factors in ischemic stroke and migraine in children

OBJECTIVE

To evaluate the contribution of antiphospholipid antibodies (aPL) and thrombomodulin (Thm) in the pathogenesis of stroke and migraine in children.

MATERIALS AND METHODS

Ninety children were included in the study: 30 children (4-15 years) after an ischemic stroke of an unknown etiology; 30 migrainous patients (8-15 years), who were hospitalized in the Department of Developmental Neurology, Medical University of Gdansk, Poland, and 30 healthy children of the same age.

RESULTS

The statistical analysis showed an increase in the values of anticardiolipin antibodies (aCL), anti beta2-glycoprotein 1 (beta2-GP1) and Thm in children with stroke and migraine than in the control group. The resultant values were higher, but stayed at standard.

CONCLUSION

The possible role of prothrombotic factors in individual cases of pediatric stroke and migraine cannot be excluded.

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.

Antiphospholipid antibodies in young adults with stroke

BACKGROUND

Antiphospholipid antibodies have been associated with a clinical syndrome consisting thrombosis and recurrent, unexplained fetal loss.

METHODS

The literature pertaining to stroke associated with antiphospholipid antibodies, with emphasis on stroke in young adults, was reviewed.

RESULTS

Antiphospholipid antibodies are an independent risk factor for stroke in young adults in five of six studies. Multiple antiphospholipid specificities or the Lupus Anticoagulant were tested in addition to anticardiolipin antibody in these studies. In the single study that found no increased risk for stroke, only anticardiolipin antibody was tested. Only one of these studies evaluated for risk of recurrent stroke in young adults with antiphospholipid antibodies and found it to be increased. No treatment trials have been conducted in young adults with antiphospholipid antibodies and stroke. In the single treatment trial comparing aspirin and low-INR producing doses of warfarin to prevent recurrent stroke, both were found to be equally effective.

CONCLUSIONS

Antiphospholipid antibodies, particularly Lupus Anticoagulant, is an independent risk factor for first and possibly recurrent ischemic stroke in young adults. The best therapeutic strategy for preventing antiphospholipid antibody-associated recurrent stroke is not clear.

Infarctus cérébraux artériels d’origine hématologique : expérience lausannoise et revue de la littérature

INTRODUCTION

Hematological diseases are seldom found as the etiology of ischemic strokes, but are frequently investigated by expensive laboratory tests after a first cerebral vascular event.

METHODS

In the Lausanne Stroke Registry, we retrospectively reviewed the cases of patients hospitalized between 1979 and 2001 for a first ischemic arterial stroke which was attributed to a hematological etiology. Of 4697 patients, 22 (0.47 per cent) had a stroke due to one of the following hematological pathology: polycythemia vera (4), secondary polycythemia (4), essential thrombocytemia (2), secondary thrombocytosis (4), multiple myeloma (1), CIVD (1), protein S deficiency (1), antiphospholipid antibody syndrome (4), moderate homocysteinemia (1). A literature review was undertaken for each hemopathy.

CONCLUSION

In light of the results of these data, we concluded that a complete blood count provides sufficient hematological screening for the majority of patients hospitalized for an arterial stroke. The antiphospholipid antibody syndrome is a rare cause of cerebral infarction, which needs to be investigated in young patients, in cases of multiple or recurring stroke or in the presence of a typical history. Inherited thrombophilias are not a significant risk factor for arterial cerebral infarction and their investigation is only warranted for a sub-group of young patients with a cryptogenic stroke, in which group the prevalence is slightly increased. Moderate homocysteinemia must be considered as a cerebrovascular risk factor of minor importance, but potentially treatable by a substitution of vitamin B12, B6 and folates. The efficacy of this substitution in the prevention of cardiovascular events needs yet to be demonstrated.

APS and the brain

Antiphospholipid antibody syndrome (APS) may present with neurological syndromes. Cerebrovascular disease, chorea/ballismus, epileptic seizures, headache, cognitive impairment, transverse myelopathy, Devic's syndrome and multiple sclerosis-like presentations feature among others. Cerebrovascular disease is one of the most common presenting symptoms of APS, second only to deep vein thrombosis, and accounts for half of neurological manifestations in patients with APS; accelerated atherogenesis and cardioembolism are the most likely mechanisms implicated. Though infrequent, chorea is consistently associated with APS; the pathogenetic role of antiphospholipid antibodies (APLab) in this case might be routed through cerebrovascular disease in some cases and through purely immunological pathways in others. Both ischemic and immunological mechanisms have been demonstrated in the pathogenesis of epileptic seizures, which may account for 7% of neurological manifestations in APS. Although frequent in APS, a causative link between APLab and most common types of headache (migraine and tension-type headache) is more than dubious. Cognitive impairment may derive from a well-defined clinical tableau of multi-infarct dementia. Nevertheless, (highly frequent) less severe cognitive impairment has also been associated with the presence of APLab in the absence of magnetic resonance findings. A relationship between APS and transverse myelopathy seems likely but small numbers in the studies published to date preclude definite statements; routinely testing for APLab patients with neurological manifestations suggestive of multiple sclerosis seems to be unrecommended at the present time.

Implantation of a second closure device in patients with residual shunt after percutaneous closure of patent foramen ovale

Percutaneous closure of patent foramen ovale (PFO) in patients with presumed paradoxical embolism yields complete occlusion in > 90% of patients using contemporary closure devices. Patients with a residual shunt after percutaneous PFO closure have been found at increased risk for recurrent paradoxical events. Treatment options for such patients include medical treatment using antiplatelet drugs or oral anticoagulation, surgical device removal and patch closure, and percutaneous implantation of a second closure device. We report our experience with implantation of a second closure device in 10 patients with more than a minimal residual shunt < or = 6 months after percutaneous PFO closure. Procedure and fluoroscopy times were similar for the initial and repeat intervention (32 vs. 30 min and 5 vs. 6 min, respectively; P = NS). There were no procedural complications during implantation of the second closure device. Follow-up transesophageal echocardiography 6 months after the second percutaneous intervention revealed complete PFO closure in nine (90%) patients. Therefore, implantation of a second closure device in patients with persistence of more than a residual shunt after percutaneous PFO closure appears safe and effective.

Management of the neurological manifestations of APS—what do the trials tell us?

PURPOSE

To systematically review evidence from clinical trials about the management of neurological manifestations of Antiphospholipid Syndrome (APS).

METHODS

Articles reporting case-control, cohort and prospective studies and treatment trials of primary or secondary stroke prevention in patients with aPL were identified in an OVID literature search from 1966 to 2004, using the keywords: APS, aPL and cerebrovascular disease. Articles were evaluated according to the standard system for assessing medical evidence to answer the following questions: (1) What is the role of aPL and recurrent stroke risk in both primary and secondary APS populations? (2) What is the evidence to support specific treatment strategies for secondary prevention of aPL-associated stroke? (3) What is the evidence to support specific treatment strategies for primary prevention of aPL-associated stroke?

CONCLUSIONS

(1) aPL are a risk factor for incident stroke (Grade A, established as useful for the given condition in the specified population). (2) The evidence to support the role of aPL in recurrent stroke is conflicting and, therefore, inconclusive. (3) Warfarin at moderate-intensity doses is equally effective in preventing a recurrent thrombotic event as warfarin at high-intensity doses in patients with APS (Grade A evidence, established as useful for the given condition in the specified population). (4) Warfarin, at moderate-intensity doses is as effective as aspirin (at a dose of 325 mg/day) in preventing recurrent thrombotic events in patients who are aPL-positive at the time of an initial stroke (Grade B evidence, probably useful for the given condition in the given population). (5) Currently there are no data to support the use of any prophylactic therapy in patients with aPL and no clinical manifestations for the purposes of preventing an incident stroke.