Stroke prevention by percutaneous closure of patent foramen ovale: a systematic review and meta-analysis

Atrial Fibrillation After Patent Foramen Ovale Closure: Incidence, Pathophysiology, and Management

This comprehensive review explores the incidence, pathophysiology, and management of atrial fibrillation (AF) following percutaneous closure of patent foramen ovale (PFO). Although AF is considered a common adverse event post PFO closure, its incidence, estimated at <5%, varies based on monitoring methods. The review delves into the challenging task of precisely estimating AF incidence, given subclinical AF and diverse diagnostic approaches. Notably, a temporal pattern emerges, with peak incidence around the 14th day after closure and a subsequent decline after the 45th day, mimicking general population AF trends. The pathophysiological mechanisms behind post PFO closure AF remain elusive, with proposed factors including local irritation, device-related interference, tissue stretch, and nickel hypersensitivity. Management considerations encompass rhythm control, with flecainide showing promise, and anticoagulation tailored to individual risk profiles. The authors advocate for a personalized approach, weighing factors like age, comorbidities, and device characteristics. Notably, postclosure AF is generally considered benign, often resolving spontaneously within 45 days, minimizing thromboembolic risks. Further studies are required to refine understanding and provide evidence-based guidelines.

Patent foramen ovale closure for patients with cryptogenic stroke: A systematic review and comprehensive meta-analysis of 5 randomized controlled trials and 14 observational studies

BACKGROUND

Previous review from randomized controlled trials (RCT) showed that patients with cryptogenic stroke may benefit from patent foramen ovale (PFO) closure. However, the findings from the systematic review were not clear when observational studies were also included.

METHODS

We searched MEDLINE, Embase, and Cochrane databases. The primary endpoints were recurrent stroke or transient ischemic attack (TIA). The secondary outcomes were all-cause death, atrial fibrillation (AF), and hemorrhagic events.

RESULTS

Five randomized trials and fourteen observational studies (6301 participants) were eligible. PFO closure was superior to medical therapy for stroke prevention risk ratios ([RR], 0.38; 95% CI, 0.24-0.60), but showed increased risk of AF (RR, 4.96; 95% CI, 2.31-10.7). There was no significant difference in TIA recurrence, death, and hemorrhagic events. Subgroup analyses showed that patients with factors such as substantial residual shunt, the presence of atrial septal aneurysm (ASA), male, and age <45 years had a lower risk of recurrent stroke when PFOs were closed.

CONCLUSIONS

In patients with cryptogenic stroke, PFO closure does appeared to be superior to medical therapy in stroke prevention, with an increased incidence of AF. Male, age <45 years, substantial residual shunt, and the history of ASA are the factors that will predict the benefit when PFO is closed.

Long-term outcomes of patent foramen ovale closure or medical therapy after cryptogenic stroke: A meta-analysis of randomized trials

OBJECTIVES

To examine long-term clinical outcomes with transcatheter patent foramen ovale (PFO) closure versus medical therapy alone in patients with cryptogenic stroke.

BACKGROUND

A long-standing debate regarding the optimal approach for the management of patients with PFO after a cryptogenic stroke exists.

METHODS

An electronic search was performed for randomized clinical trials (RCTs) reporting clinical outcomes with PFO closure vs. medical therapy alone after stroke. Random effects DerSimonian-Laird risk ratios (RR) were calculated. The main outcome was recurrence of stroke. Other outcomes included transient ischemic attack (TIA), new-onset atrial fibrillation/flutter (AF/AFL), major bleeding, serious adverse events, and device-related complications. All-cause mortality was also examined.

RESULTS

Five RCTs with a total of 3,440 patients were included. At a mean follow-up of 4.02 ± 1.57 years, PFO closure was associated with less recurrence of stroke (RR = 0.43; 95% CI 0.19-0.91; P = .027) compared with medical therapy alone. No difference was observed between both strategies for TIA (P = .21), major bleeding (P = .69), serious adverse events (P = .35), and all-cause death (P = .48). However, PFO closure, was associated with increased new-onset AF/AFL (P < .001), risk of pulmonary embolism (P = .04), and device-related complications (P < .001). On a subgroup analysis, stroke recurrence rate remained lower in PFO closure arm regardless of the type of closure device used (P_interaction  = .50), or the presence of substantial shunt in the majority of study population (P_interaction  = .13).

CONCLUSIONS

Transcatheter PFO closure reduces the recurrence of stroke compared with medical therapy alone, with no significant safety concerns. Close follow-up of patients after PFO closure is recommended to detect new-onset atrial arrhythmias.

Established and potential echocardiographic markers of embolism and their therapeutic implications in patients with ischemic stroke

Cardiogenic strokes comprised 11% of all strokes and 25% of ischemic strokes. An accurate identification of the cause of stroke is necessary in order to prepare an adequate preventive strategy. In this review the confirmed and potential causes of embolic strokes are presented, which can be detected in echocardiography in the context of present treatment guidelines and gaps in evidence. There remains a need for further studies assessing the meaning of potential cardiac sources of embolism and establishment of rules for optimal medical prevention (antiplatelet therapy [APT] vs. oral anticoagulation [OAC]) and interventional procedures to reduce the incidence of ischemic strokes. Currently available data does not provide definitive evidence on the comparative benefits of OAC vs. APT in patients with cryptogenic stroke or embolic stroke of undetermined source. There is a lack of antithrombotic treatment scheme in the time between stroke and the completed diagnosis of potential sources of thromboembolism.

Transcatheter closure of patent foramen ovale following cryptogenic stroke: An updated meta-analysis of randomized controlled trials

BACKGROUND

Transcatheter closure of patent foramen ovale (PFO) after cryptogenic stroke has long been a contentious issue. Herein, we pool aggregate data examining safety and efficacy of transcatheter closure of PFO compared with medical therapy following initial cryptogenic stroke.

METHODS

We searched for randomized clinical trials (RCT) that compared device closure with medical management and reported on subsequent stroke and adverse events. Stroke was considered as the primary efficacy endpoint, whereas bleeding and atrial fibrillation were considered primary safety endpoints. Data were pooled by the random effects model and I2 was used to assess heterogeneity.

RESULTS

A total of 5 RCT investigating 3630 patients met inclusion criteria. Pooled analysis revealed that device closure compared to medical management was associated with a significant reduction in stroke (RR=0.3, 95% CI=0.02-0.57). There was, however, a significant increase in atrial arrhythmias with device therapy (RR=4.8, 95% CI=2.2-10.7). We found no increase in bleeding (RR=0.80, 95% CI=0.5-1.4), death (RR=0.76, 95% CI=0.3-1.99) or "any adverse events" (RR=1.02, 95% CI=0.85-1.23) with device therapy. Sub-group analysis revealed that device closure significantly reduced the incidence of the composite primary endpoint among patients who had moderate to large shunt sizes (RR=0.22, 95% CI=0.02-0.42).

CONCLUSIONS

Transcatheter closure is associated with a significant reduction in the risk of stroke compared to medical management at the expense of an increased risk of atrial arrhythmias.

Reduced Stroke After Transcatheter Patent Foramen Ovale Closure: A Systematic Review and Meta-analysis

BACKGROUND

Recent randomized control trials (RCTs) have suggested benefit with transcatheter patent foramen ovale (PFO) closure plus antiplatelet therapy over medical treatment alone for secondary stroke prevention.

MATERIAL AND METHODS

Data sources: we searched PubMed and Ovid MEDLINE from the inception until November 10, 2017 for RCTs comparing TPFO closure to medical therapy in patients with a PFO and a history of cryptogenic stroke.

RESULTS

Five RCTs with 3,627 patients (TPFO closure = 1,829 versus medical therapy =1,798) were included. There was a decreased number of post-TPFO closure strokes compared to the medical therapy arm; 53 versus 80 strokes (odds ratio [OR] = 0.61, CI: 0.39-0.94, P = 0.03, I² = 17%). Transient ischemic attacks occurred in 43 patients after TPFO closure versus 60 patients in the medical therapy group (OR = 0.80, CI: 0.53-1.19, P = 0.26, I² = 0%). There was a higher incidence of atrial fibrillation in the TPFO closure group, which occurred in 75 patients, compared to 12 patients in the medical therapy group (OR = 5.23, CI: 2.17-12.59, P = 0.0002, I² = 43%). There was a trend toward a decreased number of neuropsychiatric events in the TPFO closure closure group compared to the medical therapy group; 42 versus 67 neuropsychiatric events (OR = 0.71, CI: 0.48-1.06, P = 0.09, I² = 0%).

CONCLUSIONS

TPFO closure plus antiplatelet therapy is superior to medical therapy in patients with a PFO and cryptogenic stroke. PFO closure is associated with new-onset atrial fibrillation and a trend toward reduced neuropsychiatric events.

Transcatheter Closure of Patent Foramen Ovale versus Medical Therapy after Cryptogenic Stroke: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Patent foramen ovale (PFO) with atrial septal aneurysm is suggested as an important potential source for cryptogenic strokes. Percutaneous PFO closure to reduce the recurrence of stroke compared to medical therapy has been intensely debated. The aim of this study is to assess whether PFO closure in patients with cryptogenic stroke is safe and effective compared with medical therapy.

METHOD

A search of PubMed, Medline, and Cochrane Central Register from January 2000 through September 2017 for randomized controlled trails (RCT), which compared PFO closure to medical therapy in patients with cryptogenic stroke was conducted. We used the items "PFO or patent foramen ovale", "paradoxical embolism", "PFO closure" and "stroke". Data were pooled for the primary outcome measure using the random-effects model as pooled rate ratio (RR). The primary outcome was reduction in recurrent strokes.

RESULT

Among 282 studies, 5 were selected. Our analysis included 3,440 patients (mean age 45 years, 55% men, mean follow-up 2.9 years), 1,829 in the PFO closure group and 1,611 in the medical therapy group. The I2 heterogeneity test was found to be 48%. A random effects model combining the results of the included studies demonstrated a statistically significant risk reduction in risk of recurrent stroke in the PFO closure group when compared with medical therapy (RR 0.42; 95% CI 0.20-0.91, p = 0.03).

CONCLUSION

Pooled data from 5 large RCTs showed that PFO closure in patients with cryptogenic stroke is safe and effective intervention for prevention of stroke recurrence compared with medical therapy.

Percutaneous closure of patent foramen ovale vs. medical treatment for patients with history of cryptogenic stroke: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Patients with history of cryptogenic stroke are more likely to have a patent foramen ovale (PFO) and should be managed with antithrombotic agents, while the alternative option is percutaneous closure of PFOs. Our aim was to perform a meta-analysis of randomized controlled trials (RCTs) comparing percutaneous closure vs. medical treatment for patients with PFO and prior cryptogenic stroke.

METHODS

Medline, Scopus and Cochrane databases were reviewed. A random-effect model meta-analysis was used and I-square was utilized to assess the heterogeneity. New ischemic stroke was defined as the primary endpoint. A sensitivity analysis was performed for Amplatzer device. Subgroup analyses were performed for different patient and PFO characteristics for the composite endpoints as defined by the included RCTs.

RESULTS

In total of 3440 patients were included in this meta-analysis. Closure devices were superior to medical therapy for prevention of recurrent ischemic strokes (HR = 0.29; CI: 0.02-0.56), but were associated with increased risk of new onset of atrial fibrillation (AF) and atrial flutter (RR = 4.67; CI: 2.22-9.81). However, in the sensitivity analysis for Amplatzer device, there was no difference between the two groups in new onset of atrial arrhythmias. Closure devices were superior across all different subgroups when compared to medical treatment with the exception of patients with a small shunt.

CONCLUSION

This meta-analysis shows that closure devices for patients with PFO and history of cryptogenic stroke can significantly decrease the risk of a new ischemic stroke. The use of Amplatzer device was not associated with increased risk of newly diagnosed atrial arrhythmias.

Meta-Analysis Comparing Patent Foramen Ovale Closure Versus Medical Therapy to Prevent Recurrent Cryptogenic Stroke

New evidence suggests that closure of a patent foramen ovale (PFO) plus medical therapy (MT; antiplatelet or anticoagulation) is superior to MT alone to prevent recurrent cryptogenic stroke. We performed a meta-analysis of randomized controlled trials that compared PFO closure plus MT with MT alone in patients with cryptogenic stroke. The efficacy end points were recurrent stroke, transient ischemia attack, and death. The safety end points were major bleeding and newly detected atrial fibrillation. Trials were pooled using random effects and fixed effects models. A trial sequential analysis was performed to assess if the current evidence is sufficient. Risk ratios (RR) were calculated for pooled estimates of risk. Five randomized controlled trials (3,440 patients) were included. Mean follow-up was 4.1 years. PFO closure reduced the risk of recurrent stroke by 58% (RR 0.42, 95% CI 0.20 to 0.91, p = 0.03). The number needed to treat was 38. The cumulative Z-line crossed the trial sequential boundary, suggesting there is adequate evidence to conclude that PFO closure reduces the risk of recurrent stroke by 60%. PFO closure did not reduce the risk of transient ischemia attack (RR 0.78, 95% CI 0.53 to 1.15, p = 0.21), mortality (RR 0.74, 95% CI 0.35 to 1.60, p = 0.45), or major bleeding (RR 0.96, 95% CI 0.42 to 2.20, p = 0.93); it did increase the risk of atrial fibrillation (RR 4.69, 95% CI 2.17 to 10.12, p <0.0001).

Right-to-left shunt and subclinical ischemic brain lesions in Chinese migraineurs: a multicentre MRI study

Background

Migraine is considered as a risk factor for subclinical brain ischemic lesions, and right-to-left shunt (RLS) is more common among migraineurs. This cross-sectional study assessed the association of RLS with the increased prevalence of subclinical ischemic brain lesions in migraineurs.

Methods

We enrolled 334 migraineurs from a multicentre study from June 2015 to August 2016. Participants were all evaluated using contrast-enhanced transcranial Doppler, magnetic resonance imaging (MRI), and completed a questionnaire covering demographics, the main risk factors of vascular disease, and migraine status. RLS was classified into four grades (Grade 0 = Negative; Grade I = 1 ≤ microbubbles (MBs) ≤ 10; Grade II = MBs > 10 and no curtain; Grade III = curtain). Silent brain ischemic infarctions (SBI) and white matter hyperintensities (WMHs) were evaluated on MRI.

Results

We found no significant differences between migraineurs with RLS and migraineurs without RLS in subclinical ischemic brain lesions.SBI and WMHs did not increase with the size of the RLS(p for trend for SBI = 0.066, p for trend for WMHs = 0.543). Furthermore, curtain RLS in migraineurs was a risk factor for the presence of SBI (p = 0.032, OR = 3.47; 95%CI: 1.12−10.76). There was no association between RLS and the presence of WMHs.

Conclusion

Overall, RLS is not associated with increased SBI or WMHs in migraineurs. However, when RLS is present as a curtain pattern, it is likely to be a risk factor for SBIs in migraineurs.

Trial registration

No. NCT02425696; registered on April 21, 2015.

Electronic supplementary material

The online version of this article (10.1186/s12883-018-1022-7) contains supplementary material, which is available to authorized users.

Patent foramen ovale and cryptogenic stroke: contemporary evidence and treatment

INTRODUCTION

Patent foramen ovale (PFO) is a common anatomical variant in the adult circulation. It is a channel allowing communication between the left and right atria and is a remnant of the foetal circulation. In approximately 25% of the population, this channel persists into adulthood. PFO has been proposed as a potential pathophysiological mechanism for cryptogenic stroke. Areas covered: This review will examine the contemporary evidence for both the association between cryptogenic stroke and PFO and the management of this condition. The authors hope to provide a comprehensive overview of the current evidence and best practice in relation to PFO closure. In addition, the authors will propose some potential avenues for future research in this controversial area and try to predict how PFOs in cryptogenic stroke will be managed in the near future. Expert commentary: In carefully selected patients with cryptogenic stroke, PFO closure represents an evidence based treatment option for the prevention of further ischemic neurological events. A multidisciplinary approach is necessary to ensure appropriate patient selection for the procedure. This should include a vascular neurologist/stroke physician and an interventional cardiologist with an interest in PFO closure.

Patent foramen ovale closure to prevent secondary neurologic events

In October of 2016 the United States Food and Drug Administration approved the Amplatzer Patent Foramen Ovale (PFO) occluder device for use in patients with cryptogenic stroke, to reduce the risk of recurrent stroke. This event followed 15years of off-label use of atrial septal occluder devices, 3 randomized trials, and enormous controversy over the efficacy of this procedure. While none of the trials reached the primary endpoint needed to prove the efficacy of PFO closure in preventing recurrent stroke, meta-analyses and 5-year follow-up of 1 trial suggest that PFO closure decreases the risk of recurrent stroke, especially in sub-groups with large shunts and atrial septal aneurysms, and especially when the Amplatzer device (rather than other devices) is used. While the relative reduction in stroke associated with PFO closure is large (about 50%), the absolute reduction is low (1-2%) and must be balanced against complications of the procedure (about 3%). Thus, PFO closure is restricted to patients with cryptogenic stroke, and depends heavily on patients' personal preferences. Uncertainties about the etiology of stroke in patients with PFO and the efficacy of PFO closure cause a difficult problem for the internal medicine specialist. At one extreme the internist may wonder if every patient with a documented PFO should be referred to a cardiologist. At the other extreme, supported by specialty society guidelines, internists may conclude that PFO closure is rarely necessary. In this paper we review the current status of PFO closure and suggest a rational strategy for this procedure.

PFO Closure for Cryptogenic Stroke: A Review and Clinical Treatment Algorithm

With a high prevalence in the general population of approximately 25%, and a prevalence in the cryptogenic stroke population approaching 40%, the propensity of a patent foramen ovale (PFO) to precipitate or enable stroke, especially in young, otherwise healthy individuals, has been the subject of much debate. With proof of concept achieved via imaging modalities documenting thrombus-in-transit, and the development of minimally-invasive percutaneous approaches to closure, multiple observational studies and, more recently, several completed randomized controlled trials have sought to answer the question of when and in whom PFO closure should occur. We describe the historical context of PFO closure and review the observational and randomized control trial evidence in this field, culminating in the recent Food and Drug Administration approval of the first dedicated closure device for PFO. Guidelines and consensus statements are discussed, and a novel treatment algorithm is proposed. Future directions in PFO closure will include new devices, further data from completed and upcoming clinical trials, and potential expansion into other disease states associated with PFO.

Patent Foramen Ovale and Cryptogenic Strokes in the Stroke in Young Fabry Patients Study

BACKGROUND AND PURPOSE

A patent foramen ovale (PFO) is disproportionately prevalent in patients with cryptogenic stroke. Without alternative explanations, it is frequently considered to be causative. A detailed stratification of these patients may improve the identification of incidental PFO.

METHODS

We investigated the PFO prevalence in 3497 transient ischemic attack and ischemic stroke patients aged 18 to 55 years in the prospective multicenter SIFAP1 study (Stroke in Young Fabry Patients 1) using the ASCO classification. Patients without an obvious cause for transient ischemic attack/stroke (ASCO 0) were divided into subgroups with and without vascular risk factors (ASCO 0+ and 0-). In addition, we looked for PFO-related magnetic resonance imaging lesion patterns.

RESULTS

PFO was identified in 25% of patients. Twenty percent of patients with a definite or probable cause of transient ischemic attack/stroke (≥1 grade 1 or 2 ASCO criterion; n=1769) had a PFO compared with 29% of cryptogenic stroke patients (ASCO 0 and 3; n=1728; P<0,001); subdivision of cryptogenic strokes revealed a PFO in 24% of 978 ASCO 3 patients (n.s. versus ASCO 1 and 2) and a higher prevalence of 36% in 750 ASCO 0 cases (P<0.001 versus ASCO 3 and versus ASCO 1 and 2). PFO was more commonly observed in ASCO 0- (n=271) than in ASCO 0+ patients (n=479; 48 versus 29%; P<0.001). There was no PFO-associated magnetic resonance imaging lesion pattern.

CONCLUSIONS

Cryptogenic stroke patients demonstrate a heterogeneous PFO prevalence. Even in case of less conclusive diseases like nonstenotic arteriosclerosis, patients should preferentially be considered to have a non-PFO-mediated stroke.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00414583.

Transcatheter closure of PFO as secondary prevention of cryptogenic stroke

This article covers the main unsolved issues regarding the potential role that the patent foramen ovale (PFO) plays in the genesis of so-called cryptogenic stroke. Some brief notions of the anatomy and epidemiology of the PFO are outlined. Subsequently, the results of the three trials on secondary prevention (medical therapy vs. transcatheter closure) in patients with PFO and a history of cryptogenic stroke are presented. The conflicting results of numerous meta-analyses derived from the three randomized controlled trials are discussed. Official scientific guidelines dispute an alleged superior efficacy of transcatheter PFO occlusion in comparison with antithrombotic therapy alone (anticoagulants or antiplatelet agents), except for selected cases of patients with documented PFO and a concomitant clinical-instrumental picture of deep venous thrombosis. Nevertheless, considering recent doubts about the presumptive thrombogenic and arrhythmogenic potential of PFO occlusion, which concerns only one of the septal occluders previously used, further in-depth investigations are warranted, centered on the use of newer dedicated devices to be tested in comparison with antithrombotic regimens alone.

Comparison of Outcomes after Device Closure and Medication Alone in Patients with Patent Foramen Ovale and Cryptogenic Stroke in Korean Population

PURPOSE

To compare the effectiveness of device closure and medical therapy in prevention of recurrent embolic event in the Korean population with cryptogenic stroke and patent foramen ovale (PFO).

MATERIALS AND METHODS

Consecutive 164 patients (men: 126 patients, mean age: 48.1 years, closure group: 72 patients, medical group: 92 patients) were enrolled. The primary end point was a composite of death, stroke, transient ischemic attack (TIA), or peripheral embolism.

RESULTS

Baseline characteristics were similar in the two groups, except age, which was higher in the medical group (45.3±9.8 vs. 50.2±6.1, p<0.0001), and risk of paradoxical embolism score, which was higher in the closure group (6.2±1.6 vs. 5.7±1.3, p=0.026). On echocardiography, large right-to-left shunt (81.9% vs. 63.0%, p=0.009) and shunt at rest/septal hypermobility (61.1% vs. 23.9%, p<0.0001) were more common in the closure group. The device was successfully implanted in 71 (98.6%) patients. The primary end point occurred in 2 patients (2 TIA, 2.8%) in the closure group and in 2 (1 death, 1 stroke, 2.2%) in the medical group. Event-free survival rate did not differ between the two groups.

CONCLUSION

Compared to medical therapy, device closure of PFO in patients with cryptogenic stroke did not show difference in reduction of recurrent embolic events in the real world's setting. However, considering high risk of echocardiographic findings in the closure group, further investigation of the role of PFO closure in the Asian population is needed.

Unresolved or Contradictory Issues About Management of Patients With Patent Foramen Ovale and Previous Cryptogenic Stroke: Additional Randomized Controlled Trials Are Eagerly Awaited

Stating a well-codified and widely accepted therapeutic conduct for patients with patent foramen ovale (PFO) and previous cryptogenic stroke is made difficult and somewhat controversial by several issues remained unresolved so far. In this short review, some aspects of the possible role played by the PFO in the pathogenesis of cryptogenic stroke are succinctly analyzed. First, some aspects of cardiovascular anatomy of the human fetus and the adult are outlined. Subsequently, the three randomized controlled trials (RCTs) that have been accomplished so far to compare the implant of a transeptal occluding device with a simple medical therapy in patients with PFO and history of cryptogenic stroke are briefly examined. These RCTs, when assessed using the “intention to treat” method, do not show a greater protective effect of therapy with transeptal device as regards the recurrences of stroke. Afterwards, there is a brief presentation of the findings of several meta-analyses that have been derived from the three above mentioned RCTs, whose results are strikingly discordant with each other. In fact, some of them come to the conclusion that the transcatheter closure of PFO does not offer significant advantages compared to antithrombotic therapy for the secondary prevention of cryptogenic stroke, while others based on subgroup analyses argue that the transcatheter closure of PFO with Amplatzer device, differently from the one performed using the STARFlex device, would be associated with significantly lower incidence of cerebrovascular events compared with medical therapy alone. Finally, the authors argue the need to adhere to the current scientific guidelines. They substantially deny an alleged superior efficacy of transcatheter PFO occlusion compared to medical therapy with antithrombotic agents (anticoagulants or antiplatelet agents), except for selected cases of patients with documented PFO and concomitant clinical-instrumental picture of deep venous thrombosis.

Embolic Strokes of Unknown Source and Cryptogenic Stroke: Implications in Clinical Practice

Up to a third of strokes are rendered cryptogenic or of undetermined etiology. This number is specifically higher in younger patients. At times, inadequate diagnostic workups, multiple causes, or an under-recognized etiology contributes to this statistic. Embolic stroke of undetermined source, a new clinical entity particularly refers to patients with embolic stroke for whom the etiology of embolism remains unidentified despite through investigations ruling out established cardiac and vascular sources. In this article, we review current classification and discuss important clinical considerations in these patients; highlighting cardiac arrhythmias and structural abnormalities, patent foramen ovale, paradoxical sources, and potentially under-recognized, vascular, inflammatory, autoimmune, and hematologic sources in relation to clinical practice.

Disorganized Systematic Reviews and Meta-analyses: Time to Systematize the Conduct and Publication of These Study Overviews?

The number of meta-analyses published annually has increased more than 20-fold between 1994 (n = 386) and 2014 (n = 8203). In examining how much of this increase in meta-analysis publication has genuinely represented novel contributions to clinical medicine and public health, it became clear that there was an abundance of redundant and disorganized meta-analyses, creating confusion and generating considerable debate. Ironically, meta-analyses, which should prevent redundant research, have become a victim of it. Recently, 17 meta-analyses were published based on the results of only 3 randomized controlled trials that studied the role of transcatheter closure of patent foramen ovale for prevention of cryptogenic stroke. In our search of the published literature, we identified at least 10 topics that were the subject of 10 meta-analyses. In the context of overlapping meta-analyses, one questions what needs to be done to put this "runaway train" back on track. In this review we examine the practice of redundant meta-analyses and the reasons for its disturbing "popularity." The registration of systematic reviews should be mandatory in prospective registries, such as PROSPERO, and the PRISMA checklist should be updated to incorporate new evidence and mandate the reference of previously published reviews and rationale for any new study.

Transcranial Doppler is Complementary to Echocardiography for Detection and Risk Stratification of Patent Foramen Ovale

BACKGROUND

In patients with patent foramen ovale (PFO), strategies are needed to identify patients at higher risk, who might benefit from PFO closure.

METHODS

We studied the frequency of detection of a right-to-left shunt (RLS) using transesophageal echocardiography (TEE) among patients with cryptogenic stroke and transcranial Doppler (TCD) to detect RLS, and analyzed the prediction of recurrent stroke according to TCD shunt grade, by detection of RLS on TEE, and by atrial septal aneurysm or mobility.

RESULTS

Among 334 patients with TCD, 69.8% were female, with a mean (SD) age of 53 (14) years, with a median follow-up of 420 days. There were 284 cases with TCD and TEE; 54 (19%) had atrial septal aneurysm or mobility. Echocardiography failed to show a RLS in 43 (15.1%) of the patients who had TCD and TEE, even in some patients with high-grade shunts on TCD: 18 (42%) were grade 3 or higher on TCD. Survival free of stroke or transient ischemic attack was predicted significantly by TCD shunt grade < 2 (P = 0.028), shunt grade < 3 (P = 0.03), and shunt grade < 4 (P < 0.0001); this was attenuated by adjustment for risk factors in Cox regression (P = 0.08). Neither RLS on TEE (P = 0.47), or atrial septal aneurysm or mobility (P = 0.08), predicted events.

CONCLUSIONS

Our findings suggest that TCD might be more sensitive than TEE for detection of RLS, which misses some cases with substantial RLS, and might be valuable for prediction of recurrent stroke or transient ischemic attack in patients with PFO. TCD complements TEE for management of suspected paradoxical embolism.

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.

How to Understand Patent Foramen Ovale Clinical Significance - Part II: Therapeutic Strategies in Cryptogenic Stroke

In the first part of this review, we reminded that patent foramen ovale (PFO) is a slit or tunnel-like passage in the interatrial septum occurring in approximately 25% of the population and that a number of conditions have been linked to its presence, the most important being cryptogenic stroke (CS) and migraine. We have also shown how, in the setting of neurological events, it is not often clear whether the PFO is pathogenically-related to the index event or an incidental finding, and therefore we thought to provide some useful key points for understanding PFO clinical significance in a case by case evaluation. The controversy about PFO pathogenicity has consequently prompted a paradigm shift of research interest from medical therapy with antiplatelets or anticoagulants to percutaneous transcatheter closure, in secondary prevention. Observational data and meta-analysis of observational studies previously suggested that PFO closure with a device was a safe procedure with a low recurrence rate of stroke, as compared to medical therapy. However, so far, published randomized controlled trials (CLOSURE I^®, RESPECT^® and PC Trial^®) have not shown the superiority of PFO closure over medical therapy. Thus, the optimal strategy for secondary prevention of paradoxical embolism in patients with a PFO remains unclear. Moreover, the latest guidelines for the prevention on stroke restricted indications for PFO closure to patients with deep vein thrombosis and high-risk of its recurrence. Given these recent data, in the second part of the present review, we aim to discuss today treatment options in patients with PFO and CS, providing an updating on patients’ management.

Role of occlusive devices to prevent thromboembolism among persons with a patent foramen ovale and prior stroke

OPINION STATEMENT

Patent foramen ovale (PFO) has been linked to stroke, presumably through the mechanism of paradoxical embolism; however, data is confusing regarding the causal relationship between PFO and embolic stroke. What has come to light in the past decade of research is that PFO closure with devices that achieve a high rate of closure may reduce the risk of recurrent stroke compared with medical therapy, but this benefit has not been shown in the general population with a PFO and cryptogenic stroke. The important question now is which patient will benefit from PFO closure for stroke risk reduction. A validated risk prediction tool is needed to help physicians determine those patients who will derive benefit from closure of PFO to prevent recurrent stroke. It is clear that even in studies with a small number of individuals and a very small number of events, there is some benefit to closure. Furthermore, improvements in closure devices and techniques have made percutaneous device closure both safe and efficacious. As such, it is not necessary to wait for a patient to have two strokes prior to serious consideration of PFO closure. We would advocate that the decision to close a PFO in the setting of a cryptogenic stroke be made at an individual level, on a case-by-case basis. Patients with high-risk features may be more likely to benefit, though who exactly comprises this population is still being elucidated. The most difficult aspect of managing this disease is the substantial number of individuals with incidental PFOs, as well as the prevalence of stroke due to other etiologies. When treating this disease, the physician must be able to weigh the likelihood of benefit versus the risk of the procedure, as well as patient preference.

Stroke in children with cardiac disease: report from the International Pediatric Stroke Study Group Symposium

BACKGROUND

Cardiac disease is a leading cause of stroke in children, yet limited data support the current stroke prevention and treatment recommendations. A multidisciplinary panel of clinicians was convened in February 2014 by the International Pediatric Stroke Study group to identify knowledge gaps and prioritize clinical research efforts for children with cardiac disease and stroke.

RESULTS

Significant knowledge gaps exist, including a lack of data on stroke incidence, predictors, primary and secondary stroke prevention, hyperacute treatment, and outcome in children with cardiac disease. Commonly used diagnostic techniques including brain computed tomography and ultrasound have low rates of stroke detection, and diagnosis is frequently delayed. The challenges of research studies in this population include epidemiologic barriers to research such as small patient numbers, heterogeneity of cardiac disease, and coexistence of multiple risk factors. Based on stroke burden and study feasibility, studies involving mechanical circulatory support, single ventricle patients, early stroke detection strategies, and understanding secondary stroke risk factors and prevention are the highest research priorities over the next 5-10 years. The development of large-scale multicenter and multispecialty collaborative research is a critical next step. The designation of centers of expertise will assist in clinical care and research.

CONCLUSIONS

There is an urgent need for additional research to improve the quality of evidence in guideline recommendations for cardiogenic stroke in children. Although significant barriers to clinical research exist, multicenter and multispecialty collaboration is an important step toward advancing clinical care and research for children with cardiac disease and stroke.

Echocardiographic findings in simple and complex patent foramen ovale before and after transcatheter closure

AIMS

Percutaneous closure of patent foramen ovale (PFO) in cryptogenic cerebrovascular events is an alternative to medical therapy. The interpretation of residual shunts after implantation of different devices for PFO with different morphologies is controversial.

METHODS AND RESULTS

Transcatheter PFO closure was performed in 123 patients with a history of ≥1 paradoxical embolism using three different devices: Amplatzer (n = 46), Figulla Occlutech (n = 41), and Atriasept Cardia (n = 36). Fifty-six patients presented with simple PFO and 67 patients had complex morphologies. All patients were studied with contrast enhanced transesophageal echocardiography (TEE) before interventional procedure and thereafter at 1 and 6 months and every 6-12 months in case of incomplete closure. Definite closure was confirmed in at least two consecutive TEE studies. Various PFO morphologies were identified by TEE before device implantation. The device size to PFO diameter ratio was significantly increased in patients with complex PFO compared with those patients with a simple PFO morphology (P < 0.05). The difference between the closure rate of S-PFO and C-PFO concerning each device type was significant (Amplatzer P = 0.0027, Figulla P = 0.0043, and Atriasept P < 0.01). The mean follow-up period was 3.4 years (median 2.7 years) with a cerebrovascular re-event rate of 2.4% per year. In three patients, thrombi were detected in the 6-month TEE controls and resolved after medical therapy. In three other patients, the implantation of an adjunctive device was necessary for residual shunt.

CONCLUSION

In our series of patients, the closure rate was dependent on PFO morphology more than occluder size and type. An adjunctive device was implanted in selected cases.

Percutaneous closure versus medical therapy alone for cryptogenic stroke patients with a patent foramen ovale: meta-analysis of randomized controlled trials

Of cryptogenic stroke patients younger than 55 years of age, up to 61% have had a patent foramen ovale (PFO). Observational studies have revealed reductions in recurrent neurologic events through PFO closure versus medical therapy, and randomized controlled trials have shown nonsignificant trends toward benefit. We systematically searched for randomized controlled trials of percutaneous PFO closure with medical therapy versus medical therapy alone in patients with cryptogenic stroke and performed a meta-analysis of treatment outcomes. The primary endpoint was combined death, stroke, and transient ischemic attack. We included 3 trials. Of 2,303 total patients, 1,150 underwent PFO closure and 1,153 received medical therapy (median follow-up period, 2.6 yr). The pooled incidence of the primary endpoint was 1.2 events per 100 patient-years in the closure group (95% confidence interval [CI], 0.2-2.3) and 1.8 in the therapy group (95% CI, 0.7-2.9) (P=0.32); the number needed to treat was 167 (range, 100-500). The corresponding pooled hazard ratio was 0.67 (95% CI, 0.44-1.01; P=0.054) in favor of closure. Closure was associated with an increased risk of atrial fibrillation: relative risk=3.51 (95% CI, 1.44-8.55; P=0.006). When stratified by device, use of the Amplatzer™ PFO Occluder resulted in significant stroke-prevention benefit over medical therapy alone: hazard ratio=0.44 (95% CI, 0.21-0.95; P=0.037). When compared with medical therapy alone, PFO closure with medical therapy showed a trend toward a decreased hazard of combined events, although the absolute event reduction was small and the number needed to treat was high.

Amplatzer PFO occluder device may prevent recurrent stroke in patients with patent foramen ovale and cryptogenic stroke: a meta-analysis of randomised trials

OBJECTIVE

To review efficacy of percutaneous closure of patent foramen ovale compared with medical therapy in prevention of recurrent strokes in patients with cryptogenic stroke.

METHODS AND RESULTS

Electronic databases; PUBMED, EMBASE, Cochrane registry and web of knowledge were searched for relevant studies. In three randomised clinical trials involving 2303 participants, risk of the recurrent strokes (pooled HR 0.62, 95% CI=0.36-1.07, P=0.09, I(2) =10%) did not show benefit with device closure when compared with medical therapy group on meta-analysis of all three trials. However, on sensitivity analysis in trials using Amplatzer PFO occluder device, the closure of PFO was associated with significantly lower recurrent strokes (pooled HR=0.44, 95% CI=0.21-0.94, P=0.03, I(2)=0%) compared with medical therapy.

CONCLUSION

The closure of PFO with Amplatzer PFO occluder device was associated with significant reduction in recurrent strokes in patients with cryptogenic stroke and patent foramen ovale. The better outcome in prevention of secondary stroke in patients with cryptogenic stroke and PFO may be associated with type of closure device used.