Prothrombotic disorders and ischemic stroke in children

Advances in the Diagnosis and Treatment of Pediatric Arterial Ischemic Stroke

Though rare, stroke in infants and children is an important cause of mortality and chronic morbidity in the pediatric population. Neuroimaging advances and implementation of pediatric stroke care protocols have led to the ability to rapidly diagnose stroke and in many cases determine the stroke etiology. Though data on efficacy of hyperacute therapies, such as intravenous thrombolysis and mechanical thrombectomy, in pediatric stroke are limited, feasibility and safety data are mounting and support careful consideration of these treatments for childhood stroke. Recent therapeutic advances allow for targeted stroke prevention efforts in high-risk conditions, such as moyamoya, sickle cell disease, cardiac disease, and genetic disorders. Despite these exciting advances, important knowledge gaps persist, including optimal dosing and type of thrombolytic agents, inclusion criteria for mechanical thrombectomy, the role of immunomodulatory therapies for focal cerebral arteriopathy, optimal long-term antithrombotic strategies, the role of patent foramen ovale closure in pediatric stroke, and optimal rehabilitation strategies after stroke of the developing brain.

Hemostatic and Thrombotic Considerations in the Diagnosis and Management of Childhood Arterial Ischemic Stroke: A Narrative Review

Although rare in children, arterial ischemic stroke (AIS) is associated with increased mortality and neurological morbidity. The incidence of AIS after the neonatal period is approximately 1-2/100,000/year, with an estimated mortality of 3-7%. A significant proportion of children surviving AIS experience life-long neurological deficits including hemiparesis, epilepsy, and cognitive delays. The low incidence of childhood AIS coupled with atypical clinical-presentation and lack of awareness contribute to delay in diagnosis and consequently, the early initiation of treatment. While randomized-clinical trials have demonstrated the efficacy and safety of reperfusion therapies including thrombolysis and endovascular thrombectomy in appropriately-selected adult patients, similar data for children are unavailable. Consequently, clinical decisions surrounding reperfusion therapy in childhood AIS are either extrapolated from adult data or based on local experience. The etiology of childhood AIS is multifactorial, often occurring in the setting of both acquired and congenital risk-factors including thrombophilia. While multiple studies have investigated the association of thrombophilia with incident childhood AIS, its impact on stroke recurrence and therefore duration and intensity of antithrombotic therapy is less clear. Despite these limitations, a significant progress has been made over the last decade in the management of childhood AIS. This progress can be attributed to international consortiums, and in selected cohorts to federally-funded clinical trials. In this narrative review, the authors have systematically appraised the literature and summarize the hemostatic and thrombotic considerations in the diagnosis and management of childhood AIS focusing on the evidence supporting reperfusion therapies, relevance of thrombophilia testing, and duration and drug choices for secondary-prophylaxis.

Percutaneous left atrial appendage closure in patients with primary hemostasis disorders and atrial fibrillation

BACKGROUND OR PURPOSE

We report our single-center experience with percutaneous left atrial appendage closure (LAAC) in patients with non-valvular atrial fibrillation (NVAF) and primary hemostasis disorders (HD).

METHODS

Consecutive patients with primary HD who underwent a percutaneous LAAC were included. Baseline characteristics, procedural data, and clinical outcomes were prospectively collected and compared with the overall LAAC cohort without HD.

RESULTS

Since 2013, among 229 LAAC, 17 patients (7%) had a primary HD: thrombocytopenia (n = 5), myelodysplastic syndrome (n = 6), von Willebrand syndrome (n = 4), type A hemophilia (n = 1), and dysfibrinogenemia (n = 1). The HD population's age ranged from 61 to 87 years, and the median CHA₂DS₂VASc was 5. Periprocedural plasmatic management was required in 47% of patients. The immediate LAAC implantation success rate was 100%. Patients received a direct oral anticoagulant (DOA) (n = 9), dual antiplatelet (n = 6), aspirin (n = 1), or no therapy (n = 1) during the first six postoperative weeks, followed with single antiplatelet (n = 16) or no therapy (n = 1) during lifelong. After 20 months, the technical success rate and procedural success rate were 100% and 94%. Zero device-/procedure-related complication and only one life-threatening bleeding occurred. Compared to patients without HD (n = 212), a baseline history of bleeding was less frequent (53% vs 91%, p < 0.001), and more patients received a perioperative blood transfusion (47% vs 4%, p < 0.001) in the HD group. The efficacy and safety outcomes did not differ between HD and non-HD cohorts.

CONCLUSIONS

Percutaneous LAAC in primary HD carriers appeared as safe and as effective as in overall LAAC population for stroke and bleeding prevention at midterm follow-up. Percutaneous left atrial appendage closure in patients with atrial fibrillation and primary hemostasis disorders. The percutaneous LAAC in primary hemostasis disorders and AF carriers requires a multidisciplinary approach. Cardiologist, anesthesiologist, and hematologist discussion is a cornerstone to assess anticoagulant contraindication, LAAC feasibility, periprocedural management, and follow-up (high). This multidisciplinary care is illustrated by the case of a 61-year-old male with hemophilia type A and recurrent hemarthrosis. Pre-LAAC assessment confirmed procedural indication and cactus LAA anatomy (left). After plasmatic management with factor VIII infusion, a WATCHMAN™ no. 21 was successfully implanted (middle). During follow-up, without antithrombotic regime, no ischemic or hemorrhagic complication occurred (right). LAA, left atrial appendage; LAAC, left atrial appendage closure; TEE, transesophageal echocardiography. Percutaneous LAAC in primary HD carriers appeared as safe and as effective as in overall LAAC population for stroke and bleeding prevention at midterm follow-up.

Risk factors, types and outcomes of arterial ischemic stroke in Polish pediatric patients: a retrospective single-center study

INTRODUCTION

Various neurological complications may occur as a consequence of arterial ischemic stroke (AIS) and have an impact on daily activity of the patients, costs of their medical care and rehabilitation. The aim of this study was to analyze risk factors, stroke symptoms and post-stroke consequences in Polish pediatric patients depending on stroke subtype.

MATERIAL AND METHODS

We retrospectively reviewed 77 children under the age of 18 years following their first AIS. Patients were white, Polish Caucasians, recruited in the Department of Pediatric Neurology at the Medical University of Silesia in Katowice (Poland). Statistical analysis was performed using Statistica 12.0.

RESULTS

Gender differed significantly between stroke subgroups (p = 0.030). The presence of focal cerebral arteriopathy (FCA) and chronic diseases was associated with type of AIS (p = 0.003 and p = 0.050, respectively). An outcome without neurological deterioration (normal outcome) was observed in 43% of children with lacunar anterior circulation infarct (LACI). Hemiparesis was present in almost all children with total anterior circulation infarct (TACI), in two thirds of children with partial anterior circulation infarct (PACI) and in almost 50% of children with LACI or posterior circulation infarct (POCI). In every child with hemiplegia the stroke symptom evolved into hemiparesis at follow-up. Additionally, patients with a normal outcome were older at the time of AIS than those with at least one neurological consequence (OR = 0.894, p = 0.034).

CONCLUSIONS

The presence and number of neurological outcomes depend on stroke subtypes. A relation between the presence of post-stroke deficits and age at onset was observed. The odds of deficit after ischemic stroke decreases by an average of 10.6% if the child is 1 year older at the time of AIS.

Features of Childhood Arterial Ischemic Stroke in China

Objective: The aim of this study was to identify the features and risk factors for arterial ischemic stroke (AIS) in children. Methods: We retrospectively analyzed the initial symptoms, clinical manifestations, risk factors, neuroradiological findings, and treatment data of 75 Chinese children aged between 1 month and 14 years (median 5.7 years) who were diagnosed with AIS in our hospital between 2013 and 2018. Results: Among these 75 cases of childhood AIS, 53 patients (70.67%) were male, and the male-to-female ratio was 2.41:1. A total of 55 cases (73.33%) had respiratory tract infection with fever. Seventy cases had lesions in the basal ganglia (46 left, 24 right). All patients were treated conservatively without thrombolytic therapy. Intravenous immunoglobulin treatment was given to children with fever and drowsiness. Conclusion: Infection was an important risk factor for children with AIS in China. Infection and thrombophilia risk factors were more likely to occur in isolation. The stroke lesions commonly occurred in the basal ganglia region.

Risk factors in childhood arterial ischaemic stroke: Findings from a population-based study in Germany

OBJECTIVE

Acute treatment of childhood arterial ischaemic stroke and prevention strategies for recurrent stroke episodes depend strongly on each child's individual risk profile. The aim of this study is to characterize risk factors for childhood stroke, their occurrence in isolation or combination, and to identify possible common risk factor patterns.

METHODS

This population-based study was conducted via ESPED, a surveillance unit for rare paediatric diseases in Germany. Children aged >28days and <18 years with an acute arterial ischaemic stroke occurring between January 2015 and December 2016 were included.

RESULTS

Among 99 reported children with arterial ischaemic stroke, 56 children were male. Male predominance was significant in adolescents from 12 years old onward. Arterial ischaemic stroke was more common in very young children <2 years of age and in adolescence. No risk factor was identified in 27 children. Hypercoagulable states (29%), cardiac disorders (24%), and arteriopathies (21%) were the most common risk factors. Some risk factor categories were more likely to be identified in isolation (i.e. cardiac disorders, prothrombotic abnormalities and chronic head and neck disorders) than others. The number of risk factors (n = 0-4) per patient and risk factor categories did not differ by age.

CONCLUSION

Although we could not identify common patterns of risk factor combinations, several risk factors occurred more likely in isolation than others. Further research should focus on the impact of isolated presumed childhood stroke risk factors like certain prothrombotic abnormalities, migraine or a patent foramen ovale. With regard to different age groups, stroke mechanisms in male adolescents require particular attention.

Congenital dysfibrinogenemia in a Japanese family with fibrinogen Naples (BβAla68Thr) manifesting as superior sagittal sinus thrombosis

: Congenital dysfibrinogenemia refers to the presence of a dysfunctional fibrinogen molecule, typically because of mutations in the fibrinogen gene. About 20% of fibrinogen gene mutations are responsible for thrombosis. Here, we described the case of a 17-year-old Japanese boy, who had a sudden stroke because of superior sagittal sinus thrombosis associated with dysfibrinogenemia. Genetic testing confirmed the presence of homozygous fibrinogen Naples (BβAla68Thr) mutation, which was previously reported as a causative mutation for thrombotic dysfibrinogenemia only in an Italian family. In this Japanese family, the patient's 12-year-old asymptomatic sister was also homozygous for this mutation. She, like her brother, was started on warfarin therapy. This report highlights the occurrence of fibrinogen Naples that has caused severe thrombotic complications in a young member of a Japanese family.

Arterial Ischemic Stroke in Children and Young Adults

PURPOSE OF REVIEW

This article reviews risk factors, recurrence risk, evaluation, management, and outcomes of arterial ischemic stroke in children and young adults.

RECENT FINDINGS

The risk for recurrence and mortality appear to be low for neonatal and childhood stroke. Most children have relatively mild deficits, but those who have greater neurologic deficits, poststroke epilepsy, or strokes early in life are at risk for lower overall cognitive function. Stroke recurrence and long-term mortality after stroke in young adults are greater than originally thought. Cognitive impairments, depression, and anxiety are associated with higher levels of poststroke unemployment and represent targets for improved poststroke care. Poststroke care in young adults involves more than medical management. Self-reported memory and executive function impairments may be more severe than what is detected by objective measures. Assessment of possible cognitive impairments and appropriate management of psychological comorbidities are key to maximizing the long-term functional outcome of stroke survivors.

SUMMARY

Childhood and young adult stroke survivors survive for many more years than older patients with stroke. To ensure that these survivors maximize the productivity of their lives, neurologists must not only optimize medical management but also recognize that impairments in cognition and mood may be remediable barriers to long-term functional independence.

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.

Acute Ataxia in Childhood: 11-Year Experience at a Major Pediatric Neurology Referral Center

We categorized the causes of acute ataxia in the pediatric population-referred to the Division of Neurology-at a large, urban pediatric medical center. Of the 120 cases identified over the past 11 years, post-infectious cerebellar ataxia was the most commonly diagnosed (59%), followed by drug intoxication, opsoclonus-myoclonus ataxia syndrome, episodic ataxia, acute cerebellitis, cerebellar stroke, ADEM, meningitis, cerebral vein thrombosis, Leigh's disease, Miller-Fisher syndrome, and concussion. Among the patients with post-infectious cerebellar ataxia, 85% were 1-6 years old and all had a history of antecedent viral illness. CSF pleocytosis was present in 40% of patients; all had normal brain MRIs. The majority (91%) recovered within 30 days. We conclude that post-infectious cerebellar ataxia remains the most common cause of acute ataxia in childhood and that it carries a good prognosis. We also differentiate acute post-infectious cerebellar ataxia from other causes with similar presentations.

Fibrinogen alpha and beta gene polymorphisms in pediatric stroke--case-control and family based study

BACKGROUND/PURPOSE

Data on the role of the -455G > A polymorphism of the gene encoding β fibrinogen subunit (FGB) and the Thr312Ala polymorphism of the gene for the α fibrinogen subunit (FGA) in childhood ischemic stroke are insufficient. Therefore the aim of the study was to evaluate a possible association between these two polymorphisms and arterial ischemic stroke.

METHODS

The study group consisted of 85 children after ischemic stroke, 146 of their parents and 159 controls. Both polymorphisms were genotyped using the restriction fragment length polymorphism method. Two study designs were used: a case-control model and a family-based transmission-disequilibrium test. Statistica 7.1 and EpiInfo 6 softwares were used in all analyses.

RESULTS

In the TDT test, a tendency to a higher transmission of the 312Ala allele of the FGA gene and the -455A allele of the FGB gene was observed, however, it was statistically non-significant. The frequencies of alleles and genotypes of both FGA and FGB genes polymorphisms did not differentiate children from both groups also in the case-control model. Additive or synergistic effects between FGA and FGB genes polymorphisms were not observed.

CONCLUSION

An analysis of the results obtained in this study and a critical review of previously published data indicate that examined gene polymorphisms are not related to ischemic stroke in children.

Multiple cerebral sinus thromboses complicating meningococcal meningitis: a pediatric case report

Background

Cerebral venous sinus thrombosis (CVT) is a rare and potentially life-threatening condition in the pediatric population. The clinical presentation is frequently nonspecific; thus diagnosis is often delayed or missed.

Case presentation

A previously healthy 8 month-old boy was diagnosed with meningococcal meningitis. At hospital admission, an urgent non contrast-enhanced computed tomography (CT) of the head and neck was performed with normal results. Ceftriaxone was promptly started and the clinical condition of the patient improved. However, on the 7^th day of hospitalization, the child suddenly manifested irritability and lethargy. An urgent contrast-enhanced CT of the head and neck was immediately performed, revealing thrombosis of the superior sagittal, transverse and rectus sinuses. A thrombophilic evaluation was performed, revealing hyperhomocysteinemia and methylenetetrahydrofolate reductase (MTHFR) variants (C677T and A1298C).

Conclusions

The causes of CVT may be categorized into three main groups: hypercoagulable states, conditions causing blood flow disturbances, and all causes of inflammation or infection. In this case report, we observed more than one risk factor that predisposed the patient to CVT. Consequently, even if a causative factor is detected, a thrombophilic blood evaluation should be performed. In fact, in case of a prothrombotic condition, the patient’s family should be advised that prompt administration of anticoagulant is necessary in the event of situations that could lead to thrombosis. Finally, CVT may be considered a possible complication of infection even when recent imaging results are normal. A prompt CVT diagnosis is required to obtain a good outcome. Delayed diagnosis is mainly due to the rarity of the disease and physicians’ unawareness of this type of complication.

The role of genetic risk factors in arterial ischemic stroke in pediatric and adult patients: a critical review

The incidence of arterial ischemic stroke (AIS) in childhood (about 2-13 per 100,000 children a year) is much lower than the incidence in the adult population. Still, adverse outcomes of acute brain ischemia in childhood include death (10% of AIS children), neurological sequel, epileptic seizures (over 50%) and recurrence (over 20%). The knowledge of childhood stroke etiopathogenesis is still insufficient and the diagnostic and therapeutic procedures--controversial. Risk factors for childhood stroke differ from those observed in adults due to differing exposure to external risk factors. The most frequently reported risk factors for pediatric ischemic stroke are cerebral arteriopathies and vascular malformations, cardiac diseases, infections, traumas and metabolic diseases. Because of its multifactorial etiology pediatric AIS probably has a multigenic inheritance pattern. The genetic susceptibility to AIS may be determined by specific polymorphic variants encoding markers of hemostasis regulation and they are some of the most important targets in searching for genetic determinants in pediatric AIS. The authors have reviewed the recent literature on risk factors of childhood ischemic stroke with the focus on genetic factors like polymorphisms of genes encoding coagulation factors II, V, VII and XIII, MTHFR, fibrinogen beta, and compared them with the results performed in adult patients.

Inherited thrombophilia in childhood arterial stroke: data from Lebanon

Pediatric ischemic stroke still represents a burden, and more than half of the survivors will experience cognitive or motor disabilities. The objective of this study was to investigate the role of thrombophilia in a cohort of children with arterial ischemic stroke. The records of infants and children with clinically and radiologically confirmed stroke were reviewed. Patients with venous or perinatal stroke were not included. Thirty-three patients were diagnosed with arterial ischemic stroke. The male/female ratio was 1.75:1. The median age was 4 years. The most frequent clinical manifestations were hemiparesis (54.5%) and seizures (33.3%). Genetic thrombophilia testing was available on 24 patients. Nine of the 24 patients (37.5%) were heterozygous for factor V Leiden. None of the patients carried the factor II G20210A variant. Ten patients (41.7%) were heterozygous and 3 (12.5%) were homozygous for methylenetetrahydrofolate reductase (MTHFR) C677T variant. Fifteen patients (62.5%) had one or more genetic polymorphism. Factor V Leiden was significantly associated with arterial ischemic stroke (P < 0.001). Stroke recurred in 2 children with multiple risk factors and MTHFR C677T mutation. Factor V Leiden is one of the major genetic risk factors for pediatric arterial ischemic stroke in Lebanon. MTHFR C677T was prevalent among patients with recurrent stroke.

Stroke in the immature brain: review of pathophysiology and animal models of pediatric stroke

Pediatric stroke research presents many challenges. Relatively low incidence, need for age stratification, diverse etiologies, delays in diagnosis, lack of an established age-based stroke severity scale and outcome measures are only some of the issues that have prevented the implementation of clinical trials in infants and children with stroke. Experimental animal models of pediatric stroke, therefore, are critical to understanding the pathophysiology and management of ischemic brain damage in the immature brain, and provide the necessary platform for future clinical trials. In this review we discuss the pertinent clinical aspects of pediatric stroke, the pathophysiology of stroke in the developing brain and the animal models established to study basic mechanisms as well as translational issues in pediatric stroke.

Arterial ischemic stroke in childhood: risk factors and outcome in old versus new era

Risk factors of children with arterial ischemic stroke were retrospectively evaluated. The children were grouped according to values on developing diagnostic tools: 13 in the old era (1987-1994) and 18 in the new era (1995-2004). The old era battery included 5 tests: protein C, protein S, antithrombin, lupus anticoagulants, and anticardiolipin antibodies. The new era battery added 5 more tests: homocystine level, factor VIII level, mutations for factor V Leiden and prothrombin G20210A, and lipoprotein (a) level. At least 1 risk factor was found in 5 of 13 children (38.5%) in the old era and in 8 of 18 (44.4%) in the new era. The extended battery for prothrombotic disorders revealed 7 risk factors in 4 children (22.2%) in the new era, whereas the limited battery identified a single risk factor in 1 child (7.7%) in the old era. For the correct etiologic identification, prothrombotic risk factors should be extensively evaluated in patients with arterial ischemic stroke.

Risk factors for perinatal arterial stroke: a study of 60 mother-child pairs

The objective of the present study was to examine demographic, historical, and prothrombotic risk factors in infants with perinatal arterial stroke and their mothers. Risk factors were evaluated in 60 mother-child pairs with perinatal arterial stroke. Prothrombotic factors analyzed included the DNA mutations factor V Leiden, prothrombin 20210, MTHFR C677T and A1298C; serum activity levels for protein C, protein S, and antithrombin III; serum levels of lipoprotein(a); and, in the mothers, antiphospholipid antibodies. Boys predominated, 36:24. There were four twin sets. Sixty percent were term and 22% were post-date. Ten were large for gestational age. Five mothers had abdominal trauma. Nine mothers (15%) had preeclampsia. Emergency caesarean section was performed in 17 cases (28%). Eight placental exams revealed seven with abnormalities. Seizures were the presenting sign in 70%, and 30% presented with early handedness or cerebral palsy. Prothrombotic risk factors were found in 28 of 51 mothers (55%) and 30 of 60 children (50%). Forty-one pairs (68%) had at least one abnormality in mother, child, or both. Long-term sequelae included cerebral palsy (40 of 51; 78%), cognitive impairment (35 of 51; 68%), seizures (23 of 51; 45%), and microcephaly (26 of 51; 51%). Perinatal arterial stroke is the result of multifactorial, synergistic fetal and maternal factors among which the prothrombotic factors, both fetal and maternal, appear significant.

Cerebral sinovenous thrombosis in children

Cerebral sinovenous thrombosis (CSVT) is a rare but increasingly recognized disease process in children. In the pediatric population, the etiologies of CSVT are multiple and the outcomes are variable. The current therapies for CSVT include anticoagulation, thrombolysis, hydration, surgery, and supportive care. Adult studies, pediatric case studies, and expert opinion form the basis for these treatment strategies. International cooperative efforts are currently being undertaken to collect data on pediatric stroke patients, including CSVT. These multicenter collaborations are needed to increase our understanding of the incidence, risk factors, treatment modalities, and outcomes of CSVT in pediatric populations.

Moya moya syndrome in a child with pyruvate kinase deficiency and combined prothrombotic factors

A 13-year-old Greek girl with pyruvate kinase deficiency and moya moya angiographic pattern is reported. She also had raised serum lipoprotein (a) concentration and was homozygous for the C677T mutation of the methylenetetrahydrofolate reductase gene. She presented with neonatal onset of anemia, hemolytic and aplastic crises, especially during infections, stroke, and also progressive motor and mental deterioration. A digital cranial angiography at 13 years revealed the typical angiographic findings of moya moya angiopathy. This is likely the first patient with pyruvate kinase deficiency and moya moya syndrome and also the combination of elevated serum lipoprotein (a) concentration and the C677T mutation of the methylenetetrahydrofolate reductase gene to be reported. In patients with pyruvate kinase deficiency and moya moya syndrome, a search for raised serum lipoprotein (a) concentrations and the C677T mutation of the methylenetetrahydrofolate reductase gene should be considered.

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.

Prothrombotic abnormalities in childhood ischaemic stroke

Childhood ischaemic stroke, incorporating arterial ischaemic stroke and cerebral sinus venous thrombosis, is associated with significant morbidity and mortality in children. The majority of cases in children present with well-recognised risk factors. The appreciation of the role prothrombotic abnormalities have in disease states is developing rapidly. Prothrombotic abnormalities are abnormalities of the coagulation system, fibrinolytic system, endothelial cells or platelets that lead to a reduced threshold for pathological thrombus formation. Our understanding of the role of prothrombotic abnormalities in childhood ischaemic stroke is increasing and has a direct bearing on the development of effective management and prevention strategies. We provide a brief background of prothrombotic abnormalities and review the available literature on prothrombotic markers in childhood ischaemic stroke. Overall, prothrombotic abnormalities have been identified in 20-50% of children presenting with AIS and 33-99% of children with cerebral sinus venous thrombosis. There appear to be a number of associations emerging including an increased frequency of factor V Leiden mutation, elevated lipoprotein (a), protein C deficiency and antiphospholipid antibodies in children presenting with arterial ischaemic stroke. The pathogenic role of prothrombotic abnormalities as predisposing to initial and recurrent childhood ischaemic stroke is becoming increasingly evident. The impact on treatment, however, will only be clarified with carefully designed, multi-institutional prospective studies.

Profile of pediatric hemiparesis

Our objective was to determine the clinical spectrum of pediatric hemiparesis by identifying the relative frequency of various diagnoses and comorbid conditions seen in these children. Case records of all patients with hemiparesis in a single practice over an 11-year period were reviewed with reference to clinical features, etiologic determination, and comorbid conditions. Ninety-two children were identified: 73 (79.3%) had a congenital hemiparesis and 19 (20.7%) had an acquired hemiparesis. An abnormal perinatal history (P = .003), prematurity (P = .016), and younger age at onset of symptoms (P < .001) were associated with a congenital hemiparesis. The overall etiologic yield was 83.7% (82.2% in the congenital and 89.5% in the acquired). The top four etiologic entities were cerebrovascular ischemia (40.2%), periventricular leukomalacia (18.5%), intracranial hemorrhage (16.3%), and cerebral dysgenesis (13%). Factors predictive of establishing an underlying etiology included birth prior to 34 weeks' gestation (P = .034), global developmental delay (P = .048), epilepsy (P = .024), and having appropriate imaging modalities (P = .001). Half of these children had a concurrent global developmental delay, associated epilepsy (odds ratio 3.67; 95% confidence interval 1.40-9.72), and prematurity (odds ratio 5.41; 95% confidence interval 1.56-18.80). A third of these children developed epilepsy. Multivariate predictive factors for epilepsy included global developmental delay (odds ratio 4.20; 95% confidence interval 1.44-12.27), cerebrovascular ischemia (odds ratio 5.10; 95% confidence interval 1.76-14.77), and term birth (odds ratio 3.87; 95% confidence interval 1.20-12.56). The majority of children with hemiparesis have a congenital etiology. The diagnostic yield is higher than previously reported; however, specific underlying etiologies need to be better determined. Comorbid conditions of global developmental delay and epilepsy have a high prevalence in this population, contributing to overall morbidity.

Iron deficiency and thrombosis: literature review

Compared to primary thrombocytosis such as that caused by essential thrombocytosis, reactive thrombocytosis is generally regarded as benign. However, reactive thrombocytosis has infrequently been reported to cause severe and even fatal complications. Two fatal cases of reactive thrombocytosis and iron deficiency anemia associated with peripheral/pulmonary vascular and cerebrovascular thrombosis are described. The literature on thrombosis and reactive thrombocytosis associated with iron deficiency anemia is reviewed.

Factor V Leiden and its effect on children with cardiac pathology

Factor V Leiden thrombophilia, formed by a genetic mutation, slows the body's anticoagulation response to clot formation. First described in 1994, factor V Leiden mutation has been identified as a contributing risk factor for venous thromboembolism. Although venous thromboembolism is considered rare in the pediatric population, Factor V Leiden has implications for certain at-risk pediatric patients.

Thrombosis during infancy and childhood: what we know and what we do not know

Despite underlying illnesses, children have a greater chance to survive and are expected to live 6 to 8 decades following an episode of venous or arterial thrombosis. The disproportionate benefits of preventing thrombosis and its sequelae in pediatric patients are evident. Therefore, it is necessary to develop appropriate strategies for diagnosis and management of thromboembolic events in children and to understand their acute and long-term effects. There still are many unanswered questions and clinical trials are being designed to help study these important issues.

Acute myocardial infarction in a child: possible pathogenic role of patent foramen ovale associated with heritable thrombophilia

We report an 8-year-old girl who presented with clinical features of an acute myocardial infarction. The angiographic appearance of the coronary arteries was normal. A thrombophilic state caused by a homozygote genotype for the prothrombin G20210A mutation was detected, and a patent foramen ovale (PFO) with right-to-left shunting after Valsalva maneuver was demonstrated by transesophageal contrast echocardiography. No other embolic source was identified. We suggest that paradoxical embolization through a PFO resulted in a myocardial infarction in this young patient with hereditary thrombophilia. We closed the patient's PFO with a 25-mm PFO occluder. She was anticoagulated with warfarin for 6 months. After 6 months, a contrast echocardiogram showed no evidence of residual atrial shunt. There has been no evident recurrent paradoxical embolization.

Factor V Leiden and perioperative risk

Factor V Leiden (FVL) is the most common known inherited cause of thrombophilia; it is present in approximately 5% of the Caucasian population. Although the risk of venous thrombosis associated with this polymorphism in various medical settings is well described, its effect on perioperative risk is only beginning to be explored. Specifically, there are few studies addressing the potential risks of FVL in the surgical population, in which both hemorrhagic and thrombotic complications convey substantial clinical and economic significance. There are speculations and unproven hypotheses regarding FVL in this population, and these therefore highlight the need to comprehensively address this issue. This review will describe the physiology of the FVL mutation, briefly clarify its risk in the nonsurgical setting, and assess current data regarding FVL in noncardiac and cardiac surgery. Finally, a summary of current clinical evidence and a plan for more detailed investigation of this potentially significant risk factor will be proposed.

Arterial ischaemic stroke in children

OBJECTIVE

Arterial ischaemic stroke (AIS) in childhood is a serious disorder about which little is published. The aim of this study is to determine the epidemiology and outcome of AIS in Australian children.

METHODS

Cases of childhood AIS occurring at the Royal Children's Hospital, Melbourne 1993-2001, were identified by medical record search using International Classification of Disease Codes. Information was collected on demographics, risk factors, arterial distribution, results of thrombophilic testing, management and outcome.

RESULTS

During the 8 years of review 95 patients presented with 98 cases of AIS calculating an incidence of 1.8 per 100000 children per year. Children less than 12 months of age represented greater than one third of all cases. Identifiable risk factors were present in 64% of cases with congenital heart disease the major risk factor. Thrombophilic testing was incomplete with initial abnormalities present in 18% of cases tested. The estimated stroke-related mortality was 8.4%. Of the patients who survived and who had follow-up details available, 78% had a neurological deficit. Twenty-six patients (26%) received anticoagulation. There was no statistically significant association between treatment with anticoagulation and normal neurological outcome.

CONCLUSION

AIS is over-represented in children under 12 months of age and results in death or residual neurological impairment in the majority of cases. Further prospective studies are needed to identify risk factors for poor outcome. The recently established Australian and New Zealand Stroke and Thrombophilia Registry should provide important information on clinical and laboratory based risk factors and create a basis for international clinical trials to improve the outcome of childhood AIS.

Cerebrovascular disorders

Arterial ischemic stroke is being recognized more commonly in the pediatric population. The etiologies differ greatly from those seen in adults. The most common etiologies are congenital heart disease and sickle cell disease. Children may present with or without hemiparesis and may have fever, headache, and depressed level of consciousness. A high index of suspicion is needed to diagnose stroke. Although clinical studies are scarce in children, besides early diagnosis, early specialized care with careful attention to detail ensuring adequate oxygenation and ventilation, prevention of hyperthermia and seizures, and maintenance of blood pressure and metabolic balance are important and likely improve outcome in these children. Selective children may also benefit from anticoagulant therapy, and, as the interval to diagnosis decreases, thrombolytic therapy may become an option although safety data are required. Children with acute stroke should be rapidly transported to and cared for in a pediatric center with a specialized stroke team or access to acute stroke protocols.

The paediatric overview

Stroke in children, both ischaemic and haemorrhagic, is increasingly recognised as an important paediatric illness. This review looks at the wide number of causes, highlighting the fact that often no single factor is causative on its own. There has been an increased recognition worldwide of the importance of sickle cell disease and of the importance of venous sinus thrombosis. Radiology is mandatory in diagnosis and management. Unfortunately, it is not always possible to extrapolate experience from adult stroke in terms of management of these children, and further detailed trials are necessary to understand the natural history, outcome and best forms of management.

Thromboembolic diseases of childhood

Over the last decade, pediatric thrombophilia programs have emerged around the world as a new discipline in pediatric hematology. These programs specialize in the diagnosis, prevention and treatment of children with thromboembolic events (TEs) in both the venous and arterial systems. The need for separate pediatric programs has been discussed previously. (J Pediatr Hematol Oncol 1997; 19: 7-22.) The following article will update previous reviews (Hematol Oncol Clin North Am 1998; 12: 1283-1312; Thromb Haemost 1997; 78: 715-725) and will concentrate on three aspects: (1) The risk factors for acquiring TEs; (2) The confirmatory diagnostic tests used in children with TEs; and (3) The different antithrombotic agents used for prevention and treatment. The current knowledge in respect to the above points is only the "tip of the iceberg". Well-designed prospective trials are required to establish the contribution of congenital prothrombotic disorders, appropriate diagnostic strategies, and optimal therapy for children with TEs.

Coagulopathies and arterial stroke

Although hypercoagulable states are most often associated with venous thrombosis, arterial thromboses are reported in protein S, protein C, and antithrombin III deficiencies, factor V Leiden and prothrombin gene mutations, hyperhomocysteinemia, dysfibrinogenemia, plasminogen deficiency, sickle cell disease, and antiphospholipid antibody syndrome.

Arterial strokes in children

Pediatric stroke has received special attention in the recent literature. It is now recognized as an important cause of mortality and morbidity in pediatric population. Varied and poorly specific symptomatology as well as overlapping risk factors makes the diagnosis of stroke in childhood challenging. Therapy remains controversial. The use of anticoagulation and thrombolysis in the management of acute stroke in children has not been systematically studied. In this article, we discuss the natural history, investigation, and treatment of pediatric arterial hemorrhagic and ischemic strokes.

Systemic lupus erythematosus and antiphospholipid syndrome in children and adolescents

Systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) can be associated with significant morbidity in children and adolescents. Renal involvement in SLE appears to be more severe and more frequent in the pediatric age group, with the major predictors for poor outcome being the severity of histopathologic lesions, severity of renal impairment at diagnosis, and hypertension. In addition to currently recognized cardiovascular and pulmonary involvement, accelerated atherosclerosis is of increasing concern in young individuals with SLE, because of both disease effects and medication usage. Neuropsychiatric SLE seen in childhood ranges from subtle cognitive dysfunction to severe central nervous system involvement; however, there is controversy over the value of different diagnostic studies. APS in children may be associated with SLE, idiopathic, or associated with viral infections. Systemic anticoagulation is recommended for patients with thrombotic events, but long-term management has not been well studied in children.

Prothrombotic disorders in children with moyamoya syndrome

BACKGROUND AND PURPOSE

Moyamoya syndrome is an uncommon chronic occlusive cerebrovascular disease in children. The origin of moyamoya syndrome remains undetermined. The role of the prothrombotic disorders contributing to its pathogenesis has not been completely elucidated. The purpose of this study was to determine the frequency of prothrombotic disorders in a pediatric population with moyamoya syndrome.

METHODS

From May 1992 to April 2000, a prospective study of 10 consecutive children with moyamoya syndrome was carried out at a single center. Evaluation included the following assays: protein C, protein S, antithrombin, plasminogen, activated protein C resistance, factor V Leiden, and prothrombin gene mutations. Lupus anticoagulant, anticardiolipin antibodies, and anti-beta(2)-glycoprotein I antibodies assays were also performed. The clinical characteristics, underlying diseases, family history of thrombosis, radiological findings, treatment, and outcome were also recorded.

RESULTS

In our series, prothrombotic disorders were detected in 4 patients (40%). Inherited protein S deficiency was found in 1 patient; lupus anticoagulant and anticardiolipin antibodies were detected in the remaining 3 patients. One presented persistent lupus anticoagulant for 2.7 years until his death. In the case of the other 2 patients, 1 has maintained lupus anticoagulant for 9 months, whereas the other has kept anticardiolipin/anti-beta(2)-glycoprotein I antibodies for 10 months.

CONCLUSIONS

We report the hemostatic data of the largest prospective pediatric study carried out at a single center in the western hemisphere. In 4 patients (40%), a prothrombotic disorder was detected. It is tempting to speculate that these hemostatic abnormalities may contribute to the pathogenesis of moyamoya syndrome in some of our patients.