Prevention of Stroke in Patients with Patent Foramen Ovale

Echocardiographic characteristics of transcatheter closure of patent foramen ovale with mallow biodegradable occluder: A single-center, phase III clinical study

Background

Transcatheter occlusion of patent foramen ovale (PFO) has become a recognized treatment option for high-risk PFO-related diseases. However, traditional metal occluders have some disadvantages, such as permanent retention in the body, abrasion of tissues, and obstruction of access to the left side of the heart for interventional procedures. With biodegradable occluders that release non-toxic degradation products and are absorbable by the body, the risk of long-term complications could be greatly reduced. The experimental results of using a PFO-degradable occluder in beagle dogs in early stages, independently developed by Shanghai Mallow Medical Instrument Co., Ltd., showed that the occluding umbrella disc network was degraded 6 months after occlusion. The occluder also showed good memory, biocompatibility, and mechanical properties.

Methods

As one of the multi-center research units, this prospective Phase III clinical trial study included 16 patients with PFO-related complications who were treated with a degradable occluder. The follow-up period lasted for 12 months to analyze the echocardiographic characteristics and procedural feasibility.

Results

The immediate success rate of the procedure was 100% with no serious complications. Postoperative color Doppler transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) at 12 months showed that one patient with atrial septal aneurysm (ASA) had a residual shunt at the edge of the occluder, and contrast transcranial Doppler (cTCD) showed that all patients were grade I or 0 right-to-left shunts (RLS), indicating that the occlusion success rate was 100%. The occluder gradually degraded after the procedure, particularly when the umbrella disc structure became vague, and the size of the occluder decreased significantly 6 months after occlusion.

Conclusions

PFO closure with a Mallow degradable occluder has a high plugging success rate, is safe and effective, and has no serious complications. However, for PFO closure with special anatomical features, further research with a larger sample size is required. TTE can dynamically, conveniently, and accurately observe the entire degradation process of the occluder.

Clinical Trial Registration

ChiCTR1900024036.

Association Between Patent Foramen Ovale and Overt Ischemic Stroke in Children With Sickle Cell Disease

Ischemic stroke is one of the most devastating complications of sickle cell anemia (SCA). Previous studies have shown that intracardiac shunting including patent foramen ovale (PFO) can be a potential risk factor for stroke in children with SCA. This study investigates the association between PFO and overt ischemic stroke in the DISPLACE (Dissemination and Implementation of Stroke Prevention Looking at the Care Environment) study cohort of 5,247 children with SCA of whom 1,414 had at least one clinical non-contrast transthoracic echocardiogram. Presence of PFO was taken from the clinical report. Further, we assessed the association between PFO and other clinical and hemolytic factors in children with SCA such as history of abnormal sickle stroke screen [elevated Transcranial Doppler ultrasound (TCD) velocity] and patient's baseline hemoglobin. In 642 children for whom all data were available, the adjusted odds ratio (OR) for overt stroke was higher in those with PFO but this was not statistically significant (OR: 1.49, 95% CI: 0.20-11.03, p = 0.6994). With an OR of 0.85, the study suggested less PFOs in those with abnormal TCD, but this was not statistically significant (95% CI: 0.17-4.25, p = 0.8463). Overall, the prevalence of PFO in this large sub study of non-contrast echocardiography amongst children with SCA is much lower than previous smaller studies using bubble contrast echocardiography. Overt stroke was non-statistically more common in children with SCA and PFO, but there was no evidence that PFO was more common in those with abnormal TCD, the most important pediatric sickle stroke screen.

Relation between the size of patent foramen ovale and the volume of acute cerebral ischemic lesion in young patients with cryptogenic ischemic stroke

Background

Patent foramen ovale (PFO) closure is superior to medical therapy alone to prevent stroke recurrence in selected patients. Small cortical infarcts and large right to left shunts seem to identify patients who will benefit most from closure. We aimed to study the correlation between the size of the PFO and the volume of cerebral ischemic lesions in young patients with cryptogenic ischemic stroke.

Methods

PFO dimensions and acute ischemic lesion volume of 20 patients, aged<55 years, were analyzed with transesophageal echocardiography and brain magnetic resonance imaging, respectively. The association between the volume of ischemic lesions with the length of PFO, maximum separation between septum primum and septum secundum, and the combination of the twos was explored.

Results

A direct statistically significant correlation was found between cerebral lesion volume and maximum separation of septum primum and septum secundum (p=0.047). Length of PFO showed a non-significant trend towards an inverse correlation with lesion volume (p=0.603). Multiple linear regression analysis showed that cerebral lesion volume was dependent directly on maximum separation and inversely on length of PFO (regression coeff. −0,837; p= 0.057; 2,536, p=0.006, respectively).

Conclusions

These data suggest that even small PFO might be pathogenetic in case of small cerebral infarcts and that large cerebral infarcts might be PFO related if the shunt is large. If confirmed, the combination of detailed characteristics of PFO with the volume of cerebral infarct could be integrated in a new score to select patients who would take real advantage from a percutaneous closure.

Vascular Instability and Neurological Morbidity in Sickle Cell Disease: An Integrative Framework

It is well-established that patients with sickle cell disease (SCD) are at substantial risk of neurological complications, including overt and silent stroke, microstructural injury, and cognitive difficulties. Yet the underlying mechanisms remain poorly understood, partly because findings have largely been considered in isolation. Here, we review mechanistic pathways for which there is accumulating evidence and propose an integrative systems-biology framework for understanding neurological risk. Drawing upon work from other vascular beds in SCD, as well as the wider stroke literature, we propose that macro-circulatory hyper-perfusion, regions of relative micro-circulatory hypo-perfusion, and an exhaustion of cerebral reserve mechanisms, together lead to a state of cerebral vascular instability. We suggest that in this state, tissue oxygen supply is fragile and easily perturbed by changes in clinical condition, with the potential for stroke and/or microstructural injury if metabolic demand exceeds tissue oxygenation. This framework brings together recent developments in the field, highlights outstanding questions, and offers a first step toward a linking pathophysiological explanation of neurological risk that may help inform future screening and treatment strategies.

Increased prevalence of potential right-to-left shunting in children with sickle cell anaemia and stroke

'Paradoxical' embolization via intracardiac or intrapulmonary right-to-left shunts (RLS) is an established cause of stroke. Hypercoagulable states and increased right heart pressure, which both occur in sickle cell anaemia (SCA), predispose to paradoxical embolization. We hypothesized that children with SCA and overt stroke (SCA + stroke) have an increased prevalence of potential RLS. We performed contrasted transthoracic echocardiograms on 147 children (aged 2-19 years) with SCA + stroke) mean age 12·7 ± 4·8 years, 54·4% male) and a control group without SCA or stroke (n = 123; mean age 12·1 ± 4·9 years, 53·3% male). RLS was defined as any potential RLS detected by any method, including intrapulmonary shunting. Echocardiograms were masked and adjudicated centrally. The prevalence of potential RLS was significantly higher in the SCA+stroke group than controls (45·6% vs. 23·6%, P < 0·001). The odds ratio for potential RLS in the SCA + stroke group was 2·7 (95% confidence interval: 1·6-4·6) vs controls. In post hoc analyses, the SCA + stroke group had a higher prevalence of intrapulmonary (23·8% vs. 5·7%, P < 0·001) but not intracardiac shunting (21·8% vs. 18·7%, P = 0·533). SCA patients with potential RLS were more likely to report headache at stroke onset than those without. Intrapulmonary and intracardiac shunting may be an overlooked, independent and potentially modifiable risk factor for stroke in SCA.

The Role of Patent Foramen Ovale in Cryptogenic Stroke

INTRODUCTION

Almost one-third of ischemic strokes has an unknown etiology and are classified as cryptogenic stroke. Paradoxical embolism because of a patent foramen ovale (PFO) is detected in 40%-50% of these patients. Recently, PFO has been reported as a risk factor for patients of all age groups.

METHODS

In this study, 1080 ischemic stroke patients admitted to our clinic (2011-2013) were retrospectively evaluated. Age, sex, risk factors, complete blood count, vasculitis, biochemical and hypercoagulability tests, magnetic resonance imaging, magnetic resonance angiography, transthoracic echocardiography, transeosophageal echocardiography (TEE) findings, and therapeutic approaches were evaluated.

RESULTS

The age range of the participants (seven male and four female patients) was 20-60 years (mean=43.09±11.13 years). Hemiparesis (n=10), diplopia (n=2), hemianopsia (n=2), and dysarthria (n=2) were the main findings of the neurological examinations. Patient medical history revealed hypertension (n=3), asthma (n=1), deep venous thrombosis (n=1), and smoking (n=4). Diffusion-weighted imaging showed middle cerebral artery (n=8) and posterior cerebral artery (n=3) infarctions. In one case, symptomatic severe carotid stenosis was detected. In eight cases, TEE showed PFO without any other abnormalities, but PFO was associated with atrial septal aneurysm in two cases, and in one case it was associated with ventricular hypokinesia and pulmonary arterial hypertension. Antiplatelet therapy was applied to nine patients and percutaneous PFO closure operation to two patients. In a 2-year follow-up, no recurrent ischemic stroke was recorded.

CONCLUSION

PFO, especially in terms of the etiology of cryptogenic stroke in young patients, should not be underestimated. We want to emphasize the importance of TEE in identifying potential cardioembolic sources not only in young but also in all ischemic stroke patients with unknown etiology; we also discuss the controversial management options of PFO.

Closure versus medical therapy for preventing recurrent stroke in patients with patent foramen ovale and a history of cryptogenic stroke or transient ischemic attack

BACKGROUND

The optimal therapy for preventing recurrent stroke in people with cryptogenic stroke and patent foramen ovale (PFO) has not been defined. The choice between medical therapy (antithrombotic treatment with antiplatelet agents or anticoagulants) and transcatheter device closure has been the subject of intense debate over the past several years. Despite the lack of scientific evidence, a substantial number of people undergo transcatheter device closure (TDC) for secondary stroke prevention.

OBJECTIVES

To: 1) compare the safety and efficacy of TDC with best medical therapy alone for preventing recurrent stroke (fatal or non-fatal) or transient ischemic attacks (TIAs) in people with PFO and a history of cryptogenic stroke or TIA; 2) identify specific subgroups of people most likely to benefit from closure for secondary prevention; and 3) assess the cost-effectiveness of this strategy, if possible.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (July 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2014), MEDLINE (1950 to July 2014) and EMBASE (1980 to July 2014). In an effort to identify unpublished and ongoing trials we searched seven trials registers and checked reference lists.

SELECTION CRITERIA

We included randomized controlled trials (RCTs), irrespective of blinding, publication status, and language, comparing the safety and efficacy of device closure with medical therapy for preventing recurrent stroke or TIA in people with PFO and a history of cryptogenic stroke or TIA.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, assessed quality and risk of bias, and extracted data. The primary outcome measures of this analysis were the composite endpoint of ischemic stroke or TIA events as well as recurrent fatal or non-fatal ischemic stroke. Secondary endpoints included all-cause mortality, serious adverse events (atrial fibrillation, myocardial infarction, bleeding) and procedural success and effective closure. We used the Mantel-Haenszel method to obtain pooled risk ratios (RRs) using the random-effects model regardless of the level of heterogeneity. We pooled data for the primary outcome measure with the generic inverse variance method using the random-effects model, yielding risk estimates as pooled hazard ratio (HR), which accounts for time-to-event outcomes.

MAIN RESULTS

We included three RCTs involving a total of 2303 participants: 1150 participants were randomized to receive TDC and 1153 participants were randomized to receive medical therapy. Overall, the risk of bias was regarded as high. The mean follow-up period of all three included trials was less than five years. Baseline characteristics (age, sex, and vascular risk factors) were similar across trials. Intention-to-treat analyses did not show a statistically significant risk reduction in the composite endpoint of recurrent stroke or TIA in the TDC group when compared with medical therapy (RR 0.73, 95% CI 0.45 to 1.17). A time-to-event analysis combining the results of two RCTs also failed to show a significant risk reduction with TDC (HR 0.69, 95% CI 0.43 to 1.13). When assessing stroke prevention alone, TDC still did not show a statistically significant benefit (RR 0.61, 95% CI 0.29 to 1.27) (HR 0.55, 95% CI 0.26 to 1.18). In a sensitivity analysis including the two studies using the Amplatzer PFO occluder, TDC showed a possible protective effect on recurrent stroke compared with medical therapy (HR 0.38, 95% CI 0.14 to 1.02); however, it did not reach statistical significance. Safety analysis found that the overall risks for all-cause mortality and adverse events were similar in both the TDC and medical therapy groups. However, TDC increased the risk of new-onset atrial fibrillation (RR 3.50, 95% CI 1.47 to 8.35) and may be associated with the type of device used.

AUTHORS' CONCLUSIONS

The combined data from recent RCTs have shown no statistically significant differences between TDC and medical therapy in the prevention of recurrent ischemic stroke. TDC closure was associated with an increased risk of atrial fibrillation but not with serious adverse events.

Decline in mean platelet volume in patients with patent foramen ovale undergoing percutaneous closure

Introduction

The presence of patent foramen ovale (PFO) is considered a possible cause for cryptogenic stroke. The mechanism underlying the ischaemic neurological events in the presence of PFO has not been firmly established. The purpose of this study was to compare: (1) the mean platelet volume levels in PFO patients with and without a cryptogenic stroke, and (2) pre- and post-procedural mean platelet volumes (MPV) in patients undergoing percutaneous PFO closure.

Methods

Sixteen PFO patients undergoing percutaneous closure to prevent recurrent ischaemic events and 15 asymptomatic patients with PFO were enrolled in the study. Mean platelet volume was compared between patients with and without a history of stroke. We also compared pre- and postprocedural MPV levels in patients undergoing percutaneous PFO closure.

Results

Mean platelet volume, which is a marker for platelet activity, was similar in PFO patients with and without stroke (9.34 ± 1.64 vs 9.1 ± 1.34 fl; p = 0.526). Interestingly, MPV decreased significantly after percutaneous closure compared to pre-procedural levels (9.34 ± 1.64 vs 8.3 ± 1.12 fl; p = 0.001).

Conclusion

Our findings suggest interatrial communication through a PFO may be related to increased MPV and increased platelet activity.

A review of stroke and pregnancy: incidence, management and prevention

Stroke, defined as a focal or global disturbance of cerebral function lasting over 24h resulting from disruption of its blood supply, is a devastating event for a pregnant woman. This can result in long-term disability or death, and impact on her family and unborn child. In addition to pre-existing patient risk factors, the hypercoagulable state and pre-eclampsia need to be taken into account. The patterns and types of stroke affect pregnant women differ from the non-pregnant female population of child-bearing age. Like other thrombo-embolic diseases in pregnancy, stroke is essentially a disease of the puerperium. Population studies have estimated the risk of stroke at between 21.2 and 46.2 per 100,000. The US Nationwide Inpatient Sample, identified 2850 pregnancies complicated by stroke in the United States in 2000-2001, for a rate of 34.2 per 100,000 deliveries. There were 117 deaths, a mortality rate of 1.4 per 100,000. Both the mortality and disability rates were higher than previously reported, with 10-13% of women dying. With the increasing prevalence of obesity, hypertension and cardiac disease amongst women of child-bearing age, so is the incidence of stroke during pregnancy and the puerperium. In the United States, an alarming trend toward higher numbers of stroke hospitalizations during the last decade was demonstrated in studies from 1995 to 1996 and 2006 to 2007. The rate of all types of stroke increased by 47% among antenatal hospitalizations, and by 83% among post-partum hospitalizations. Hypertensive disorders, obesity and heart disease complicated 32% of antenatal admissions and 53% of post-partum admissions. In addition to pre-existing patient risk factors, the hypercoagulable state and pre-eclampsia need to be taken into account. The patterns and types of stroke affect pregnant women differ from the non-pregnant female population of child-bearing age. Like other thrombo-embolic diseases in pregnancy, stroke is essentially a disease of the puerperium.

Diagnostic value of transthoracic echocardiography for patent foramen ovale: a meta-analysis

As a non-invasive and convenient modality, transthoracic echocardiography (TTE) has been widely recommended for the diagnosis of patent foramen ovale (PFO). In this study our aim was to systematically review the diagnostic accuracy of TTE in detection of PFO. We conducted comprehensive searches in PubMed, Embase and the Cochrane Library to the end of September 1, 2012. Sixteen studies comprising 1831 patients were included in the meta-analysis. The quality of reported studies was modest. The summary sensitivity and specificity of TTE in diagnosis of PFO were 88% (95% confidence interval [CI], 79-94) and 97% (95% CI, 92-99), respectively. The positive likelihood ratio was 27.1 (95% CI, 11.2-65.1), and the negative likelihood ratio was 0.12 (95% CI, 0.07-0.22). The summary diagnostic odds ratio was 221 (95% CI, 95-518). Subgroup analyses suggested that age and initial disease may affect the accuracy of TTE in detection of PFO. The meta-analysis suggested that TTE is a test with high sensitivity and specificity in detection of PFO, but it may not be appropriate for screening for PFO in all patients, especially patients with a small right-left shunt.

Angina pectoris or myocardial infarctions, pulmonary arteriovenous malformations, hereditary hemorrhagic telangiectasia, and paradoxical emboli

Hereditary hemorrhagic telangiectasia is an autosomal dominant disorder characterized by vascular malformations, and many clinical complications are related to pulmonary arteriovenous malformations (PAVMs) because they provide direct right-to-left shunts. Paradoxical emboli through these shunts are a well-recognized cause of transient ischemic attack, stroke, and cerebral abscess. The aim of this study was to determine whether paradoxical emboli through PAVMs could manifest as cardiac ischemic events. The study included a single-center population of 98 patients with PAVMs. Eighty-four had undergone PAVM embolotherapy, and the remaining 14 patients had PAVMs too small to require embolization. Patients were interviewed by telephone and surveyed regarding their cardiopulmonary symptoms and histories of cardiac diagnoses. We found that 6 patients (which is 18% of patients with symptomatic PAVMs, n = 33, and 6% of the total cohort, n = 98) reported that they had experienced typical angina pectoris-like chest pain or had a myocardial infarction before PAVM embolotherapy. Five patients had had a cardiac catheterization, 4 had normal coronary arteries, and 1 had a single artery occlusion. In conclusion, we suggest that in patients with untreated PAVMs, cardiac ischemia can occur because of a paradoxical embolus through PAVMs to a coronary artery.

The brain's heart - therapeutic opportunities for patent foramen ovale (PFO) and neurovascular disease

Patent foramen ovale (PFO), a common congenital cardiac abnormality, is a connection between the right and left atria in the heart. As a "back door to the brain", PFO can serve as a conduit for paradoxical embolism, allowing venous thrombi to enter the arterial circulation, avoiding filtration by the lungs, and causing ischemic stroke. PFO-related strokes affect more than 150,000 people per year in the US, and PFO is present in up to 60% of migraine patients with aura, and in one out of four normal individuals. So, in such a highly prevalent condition, what are the best treatment and prevention strategies? Emerging studies show PFO-related neurovascular disease to be a multi-organ condition with varying individual risk factors that may require individualized therapeutic approaches - opening the field for new pharmacologic and therapeutic targets. The anatomy of PFO suggests that, in addition to thrombi, it can also allow harmful circulatory factors to travel directly from the venous to the arterial circulation, a concept important in finding novel therapeutic targets for PFO-related neurovascular injury. Here, we: 1) review emerging data on PFO-related injuries and clinical trials; 2) discuss potential mechanisms of PFO-related neurovascular disease in the context of multi-organ interaction and heart-brain signaling; and 3) discuss novel therapeutic targets and research frontiers. Clinical studies and molecular mapping of the circulatory landscape of this multi-organ disease will both be necessary in order to better individualize clinical treatment for a condition affecting more than a quarter of the world's population.

Toward understanding the atrial septum in cryptogenic stroke

Ischemic stroke in younger people is common, and often remains unexplained. There is a well-documented association between unexplained stroke in younger people, and the presence of a patent foramen ovale. Therefore, in the absence of a clear cause of stroke, the heart is often assessed in detail for such lower risk causes of stroke. This usually involves imaging with a transesophageal echo, and investigation for a right-to-left shunt. An understanding of the anatomy of the atrial septum, and its associated abnormalities, is important for the stroke neurologist charged with decision making regarding appropriate secondary prevention. In this paper, we review the development and anatomy of the right heart with a focus on patent foramen ovale, and other associated abnormalities. We discuss how the heart can be imaged in the case of unexplained stroke, and provide examples. Finally, we suggest a method of investigation, in light of the recent European Association of Echocardiography guidance. Our aim is to provide the neurologist with an understanding on how the heart can be investigated in unexplained stroke, and the significance of abnormalities detected.

Towards understanding the cause of stroke in young adults utilising a new stroke classification system (A-S-C-O)

BACKGROUND

Stroke in younger people is relatively common and frequently unexplained. While understanding of the causes of young stroke has improved, there remains uncertainty over the role of low-risk lesions such as a patent foramen ovale (PFO). The TOAST criteria are often used to describe stroke aetiology, but in younger people in whom PFOs are frequent, there is a very high proportion of cases attributed to cardiac embolism. The impact of using the newer A-S-C-O criteria on stroke aetiology was investigated.

METHODS

Consecutive patients with ischaemic stroke were investigated and categorised by the TOAST and ASCO1 criteria. Stroke aetiology was presented and compared by the different classification systems.

RESULTS

Of the 106 ischaemic stroke cases, by TOAST 6% were 'large artery atheroma', 11% 'small vessel occlusion', 28% 'cardioembolic', 22% 'other determined cause' and 33% 'undetermined cause'. The vascular territory and associated causes are presented. With the ASCO1 criteria, there were more cases of unclassified stroke (51.9 vs. 34.0%; p < 0.001) and fewer cases of cardiac embolism. Kappa ranged from 0.5 for 'undetermined aetiology' to 1.0 for both 'large artery atheroma' and 'other determined aetiology'. Younger cases (<45 years) were less likely to be either 'large artery atheroma' or 'small vessel occlusion'.

CONCLUSION

Using the ASCO criteria, more patients fall into the undetermined group which more accurately reflects our current uncertainty regarding the pathogenic relevance of PFOs in this age group.

Patent foramen ovale may be causal for the first stroke but unrelated to subsequent ischemic events

BACKGROUND AND PURPOSE

Studies with very long follow-up are scarce in patients with cryptogenic stroke and patent foramen ovale (PFO). Little is known about the etiology of recurrent cerebrovascular events (CVE) in PFO patients.

METHODS

We collected information on recurrent CVE in 308 patients with cryptogenic stroke and PFO and sought to determine concurrent stroke causes that had emerged or been newly detected since the index event. One hundred fifty-eight patients received aspirin (48%), clopidogrel (2%), or oral anticoagulants (50%; medical group). One hundred fifty patients underwent percutaneous PFO closure (closure group).

RESULTS

Mean age at index event was 50 years (SD 13). In 33% of patients, the index stroke or transient ischemic attack was preceded by at least 1 CVE. Mean follow-up was 8.7±4.0 years. During follow-up, 32 recurrent CVE (13 strokes and 19 transient ischemic attacks) occurred in the medical and 16 recurrent CVE (8 strokes and 8 transient ischemic attacks) in the closure group. Concurrent etiologies were identified for 12 recurrent CVE in the medical group (38%): large artery disease (9%), small artery disease (6%), cardioembolism (13%), cerebral vasculitis (3%), and antiphospholipid-antibody-syndrome (6%). In the closure group, 7 recurrent CVE had a concurrent etiology (44%): large artery disease (6%), small artery disease (19%), cardioembolism (13%), and thrombophilic disorder (6%). The frequency of concurrent etiologies did not differ between patients with recurrent CVE under medical treatment and those undergoing PFO closure (P=0.68).

CONCLUSIONS

Concurrent etiologies are identified for more than one third of recurrent ischemic events in patients with cryptogenic stroke, casting doubt on the sole causal role of PFO.

Randomized clinical trial comparing percutaneous closure of patent foramen ovale (PFO) using the Amplatzer PFO Occluder with medical treatment in patients with cryptogenic embolism (PC-Trial): rationale and design

Background

Several studies have shown an association of cryptogenic stroke and embolism with patent foramen ovale (PFO), but the question how to prevent further events in such patients is unresolved. Options include antithrombotic treatment with warfarin or antiplatelet agents or surgical or endovascular closure of the PFO. The PC-Trial was set up to compare endovascular closure and best medical treatment for prevention of recurrent events.

Methods

The PC-Trial is a randomized clinical trial comparing the efficacy of percutaneous closure of the PFO using the Amplatzer PFO occluder with best medical treatment in patients with cryptogenic embolism, i.e. mostly cryptogenic stroke. Warfarin for 6 months followed by antiplatelet agents is recommended as medical treatment. Randomization is stratified according to patients age (<45 versus ≥45 years), presence of atrial septal aneurysm (ASA yes or no) and number of embolic events before randomization (one versus more than one event). Primary endpoints are death, nonfatal stroke and peripheral embolism.

Discussion

patients were randomized in 29 centers of Europe, Canada, and Australia. Randomization started February 2000. Enrollment of 414 patients was completed in February 2009. All patients will be followed-up longitudinally. Follow-up is maintained until the last enrolled patient is beyond 2.5 years of follow-up (expected in 2011).

Trial Registration

Trial listed in ClinicalTrials.gov as NCT00166257 and sponsored by AGA Medical, Plymouth, MN, USA

Current proceedings of childhood stroke

Stroke is a sudden onset neurological deficit due to a cerebrovascular event. In children, the recognition of stroke is often delayed due to the low incidence of stroke and the lack of specific assessment measures to this entity. The causes of pediatric stroke are significantly different from that of adult stroke. The lack of safety and efficiency data in the treatment is the challenge while facing children with stroke. Nearly half of survivors of pediatric stroke may have neurologic deficits affecting functional status and quality of life. They may cause a substantial burden on health care resources. Hence, an accurate history, including onset and duration of symptoms, risk factors, and a complete investigation, including hematologic, neuroimaging, and metabolic studies is the key to make a corrective diagnosis. A prompt and optimal treatment without delay may minimize the damage to the brain.

Is patent foramen ovale a modifiable risk factor for stroke recurrence?

Although the prevalence of a patent foramen ovale (PFO) in the general population is ≈25%, it is approximately doubled among cryptogenic stroke (CS) patients. This has generally been attributed to paradoxical embolism, and many physicians recommend PFO closure to prevent recurrence. However, the benefit of PFO closure in patients with stroke has not been demonstrated. Furthermore, the epidemiology of stroke recurrence in patients with CS with PFO versus without PFO and in those with large right-to-left shunts versus small right-to-left shunts has yielded results that appear difficult to reconcile with the hypothesis that paradoxical embolism is an important cause of stroke recurrence. The purpose of this review is to critically examine the epidemiologic evidence that PFO is a potentially modifiable risk factor for stroke recurrence in patients with CS. The evidence suggests that many patients with CS and PFO have strokes that are PFO attributable, but many have strokes that are unrelated to their PFO. We introduce the concept of "PFO propensity," defined as the patient-specific probability of finding a PFO in a patient with CS on the basis of age and other risk factors. We show that this value is directly related to the probability that CS is PFO attributable. Because there is substantial heterogeneity in both PFO propensity and recurrence risk among patients with PFO and CS, stratification for PFO closure by these joint probabilities will likely prove crucial for appropriate patient selection.