PFO closure vs. medical therapy in cryptogenic stroke or transient ischemic attack: 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.

Amplatzer Patent Foramen Ovale Occluder Device-Related Complications

Patent foramen ovale (PFO) is a standard variant that is present in 25% of the whole adult population. In a certain population, PFO can lead to cerebrovascular accidents. Mechanism of cerebrovascular accidents can be by paradoxical embolization from the right circulation or in situ thrombosis. Diagnosis of a PFO-responsible cerebrovascular accident is based on a thorough work-up to exclude other possible etiologies and detect PFO on trans-thoracic or trans-esophageal echocardiography with bubble study and/or Doppler. Over the last few years, multiple studies have supported that percutaneous PFO closure is superior to medical therapy in the secondary prevention of cerebrovascular accidents. However, numerous adverse events have been linked to PFO closure devices in general compared to medical therapy as new-onset atrial fibrillation, residual shunt, device-related thrombus, bleeding, deep vein thrombosis, pulmonary embolism, and inter-atrial septal erosions. Amplatzer device is one of the PFO occluder devices approved by the FDA. Device-related adverse events have been addressed by comparing the Amplatzer device with other PFO occluder devices. Based on the new data, we expect to see more complications related to PFO closure in the coming few years. We reviewed different studies that looked at the PFO closure-related complications and the trials comparing adverse events in the Amplatzer PFO occluder device compared to other devices. Amplatzer PFO occluder device is either superior or non-statistically different from other PFO occluder devices related to new-onset atrial fibrillation and residual shunt. More studies are needed to address the other less common adverse events. Since many of the device-related complications appear many years after device placement, a long-term follow-up is recommended.

Data-driven machine-learning analysis of potential embolic sources in embolic stroke of undetermined source

BACKGROUND AND PURPOSE

Hierarchical clustering, a common 'unsupervised' machine-learning algorithm, is advantageous for exploring potential underlying aetiology in particularly heterogeneous diseases. We investigated potential embolic sources in embolic stroke of undetermined source (ESUS) using a data-driven machine-learning method, and explored variation in stroke recurrence between clusters.

METHODS

We used a hierarchical k-means clustering algorithm on patients' baseline data, which assigned each individual into a unique clustering group, using a minimum-variance method to calculate the similarity between ESUS patients based on all baseline features. Potential embolic sources were categorised into atrial cardiopathy, atrial fibrillation, arterial disease, left ventricular disease, cardiac valvulopathy, patent foramen ovale (PFO) and cancer.

RESULTS

Among 800 consecutive ESUS patients (43.3% women, median age 67 years), the optimal number of clusters was four. Left ventricular disease was most prevalent in cluster 1 (present in all patients) and perfectly associated with cluster 1. PFO was most prevalent in cluster 2 (38.9% of patients) and associated significantly with increased likelihood of cluster 2 [adjusted odds ratio: 2.69, 95% confidence interval (CI): 1.64-4.41]. Arterial disease was most prevalent in cluster 3 (57.7%) and associated with increased likelihood of cluster 3 (adjusted odds ratio: 2.21, 95% CI: 1.43-3.13). Atrial cardiopathy was most prevalent in cluster 4 (100%) and perfectly associated with cluster 4. Cluster 3 was the largest cluster involving 53.7% of patients. Atrial fibrillation was not significantly associated with any cluster.

CONCLUSIONS

This data-driven machine-learning analysis identified four clusters of ESUS that were strongly associated with arterial disease, atrial cardiopathy, PFO and left ventricular disease, respectively. More than half of the patients were assigned to the cluster associated with arterial disease.

Prior Stroke in PFO Patients Is Associated With Both PFO-Related and -Unrelated Factors

Background and Purpose: To identify factors associated with prior stroke at presentation in patients with cryptogenic stroke (CS) and patent foramen ovale (PFO).

Methods: We studied cross-sectional data from the International PFO Consortium Study (NCT00859885). Patients with first-ever stroke and those with prior stroke at baseline were analyzed for an association with PFO-related (right-to-left shunt at rest, atrial septal aneurysm, deep venous thrombosis, pulmonary embolism, and Valsalva maneuver) and PFO-unrelated factors (age, gender, BMI, hypertension, diabetes mellitus, hypercholesterolemia, smoking, migraine, coronary artery disease, aortic plaque). A multivariable analysis was used to adjust effect estimation for confounding, e.g., owing to the age-dependent definition of study groups in this cross-sectional study design.

Results: We identified 635 patients with first-ever and 53 patients with prior stroke. Age, BMI, hypertension, diabetes mellitus, hypercholesterolemia, coronary artery disease, and right-to-left shunt (RLS) at rest were significantly associated with prior stroke. Using a pre-specified multivariable logistic regression model, age (Odds Ratio 1.06), BMI (OR 1.06), hypercholesterolemia (OR 1.90) and RLS at rest (OR 1.88) were strongly associated with prior stroke.Based on these factors, we developed a nomogram to illustrate the strength of the relation of individual factors to prior stroke.

Conclusion: In patients with CS and PFO, the likelihood of prior stroke is associated with both, PFO-related and PFO-unrelated factors.

Stroke in the Young: a Global Update

PURPOSE OF REVIEW

We aim to evaluate the epidemiology, racial and gender disparity, etiology, and treatment of stroke in the younger population.

RECENT FINDINGS

The younger age group without vascular risk factors exhibits an increased prevalence of cardio-embolism in context of patent foramen ovale/atrial septal aneurysm strokes, from other determined etiology of non-atherosclerotic vasculopathy including dissection, inherited or acquired thrombophilia, and other unusual causes of stroke. Ethnic disparities also exist in certain populations. The prevalence of stroke in the young is increasing due to several factors. Since stroke is often disabling, this trend poses an enormous threat to socioeconomic stability especially in developing countries. In young patients with an absence of conventional vascular risk factors and negative preliminary stroke work-up, clinicians must consider less common causes of stroke in this population. There is prime opportunity for future investigations as there is currently a lack of evidence-based management guidelines for these uncommon etiologies based on research completed to date.

Secondary prevention of cryptogenic stroke in patients with patent foramen ovale: a systematic review and meta-analysis

The aim of our study is to compare patent foramen ovale (PFO) closure versus medical treatment and antiplatelet versus anticoagulant therapy in patients with cryptogenic stroke (CS) and PFO. We conducted a systematic review and meta-analysis with trial sequential analysis (TSA) of randomized trials. Primary outcomes are stroke or transient ischemic attack (TIA) and all-cause mortality. Secondary outcomes are peripheral embolism, bleeding, serious adverse events, myocardial infarction and atrial dysrhythmias. We performed an intention to treat meta-analysis with a random-effects model. We include six trials (3677 patients, mean age 47.3 years, 55.8% men). PFO closure is associated with a lower recurrence of stroke or TIA at a mean follow-up of 3.88 years compared to medical therapy [risk ratio (RR) 0.55, 95% CI 0.38-0.81; I² = 40%]. The TSA confirms this result. No difference is found in mortality (RR 0.74, 95% CI 0.35-1.60; I² = 0%), while PFO closure is associated with a higher incidence of atrial dysrhythmias (RR 4.55, 95% CI 2.16-9.60; I² = 25%). The rate of the other outcomes is not different among the two groups. The comparison between anticoagulant and antiplatelet therapy shows no difference in terms of stroke recurrence, mortality and bleeding. There is conclusive evidence that PFO closure reduces the recurrence of stroke or TIA in patients younger than 60 years of age with CS. More data are warranted to assess the consequences of the increase in atrial dysrhythmias and the advantage of PFO closure over anticoagulants.

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.

Closure of patent foramen ovale or medical therapy alone for secondary prevention of cryptogenic cerebrovascular events

AIMS

About one-third of ischemic stroke are cryptogenic. Paradoxical embolism through patent foramen ovale (PFO) has been identified as a possible cause of cryptogenic stroke. Therefore, PFO closure has been considered for secondary prevention of cryptogenic stroke. However, randomized clinical trials (RCTs) comparing PFO closure versus medical therapy led to conflicting results. Our objectives were to examine if PFO closure is superior to medical therapy alone for secondary prevention of cryptogenic stroke and to investigate whether PFO closure is associated with an increased incidence of atrial fibrillation/atrial flutter (AFL).

METHODS

The authors systematically searched MEDLINE for RCTs that compared PFO closure with medical therapy. Efficacy outcome was cerebrovascular event (CVE) recurrence and safety outcome was new-onset atrial fibrillation/AFL. The outcomes of interest were investigated according to device type with subgroup analyses and meta-regression.

RESULTS

The authors included eight RCTs constituting 4114 patients. Patients who underwent PFO closure had a lower risk of CVE recurrence compared with medically treated patients [relative risk (RR): 0.56; 95% confidence interval (CI) 0.40-0.80; P = 0.001; I = 30%]. This protective effect was consistent across the different device types. Patients who underwent PFO closure developed more frequently atrial fibrillation/AFL (RR 4.96; 95% CI 2.74-8.99; P < 0.00001; I = 0%), which was mainly transient and within 1 month. Atrial fibrillation/AFL risk was consistent according to device types, although marginally significant in the Amplatzer subgroup.

CONCLUSION

PFO closure might have a role in secondary CVE prevention of patients with PFO and cryptogenic stroke. However, it is associated with an increased incidence of new-onset atrial fibrillation/AFL especially within 1 month.

Patent foramen ovale and stroke

A patent foramen ovale (PFO) is a highly prevalent finding in cryptogenic ischaemic stroke, particularly in young adults. A common challenge in clinical practice is to distinguish between incidental and pathogenic PFO. Some clinical features and tools such as the Risk of Paradoxical Embolism score may help determining the probability of a stroke-related PFO. Nonetheless, the best therapeutic option to reduce stroke recurrence after a cryptogenic stroke with PFO has been a matter of debate for a long time. We review the mechanisms of stroke-related PFO, together with its clinical features and diagnostic criteria. In addition, we focus on the methodological details and results from new studies in the field of secondary prevention. In contrast to prior evidence, the data from three recent clinical trials and an updated meta-analysis favour PFO closure over medical treatment after cryptogenic stroke/TIA for the prevention of stroke recurrence. The PFO closure device procedure is not associated with higher mortality or cardiovascular events, except for a small increase in the occurrence of transient atrial fibrillation. Furthermore, the benefit of PFO closure was higher among those with atrial septal aneurysm and PFO with large right-to-left shunt. Future studies should address pending issues such as the option for anticoagulants or antiplatelet in patients not undergoing closure, the duration of antiplatelet treatment after PFO closure and the role of PFO closure in patients older than 60.

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.

Closure of Patent Foramen Ovale Versus Medical Therapy in Patients With Cryptogenic Stroke or Transient Ischemic Attack

Background and Purpose—

Previous systematic reviews and meta-analyses compared the efficacy and safety of patent foramen ovale (PFO) closure versus medical treatment in patients with cryptogenic stroke or transient ischemic attack (TIA). Recently, new evidence from randomized trials became available.

Methods—

We searched PubMed until September 24, 2017, for trials comparing PFO closure with medical treatment in patients with cryptogenic stroke/TIA using the items: stroke or cerebrovascular accident or TIA and patent foramen ovale or paradoxical embolism and trial or study.

Results—

Among 851 identified articles, 5 were eligible. In 3627 patients with 3.7-year mean follow-up, there was significant difference in ischemic stroke recurrence (0.53 versus 1.1 per 100 patient-years, respectively; odds ratio [OR], 0.43; 95% confidence intervals (CI), 0.21–0.90; relative risk reduction, 50.5%; absolute risk reduction, 2.11%; and number needed to treat to prevent 1 event, 46.5 for 3.7 years). There was no significant difference in TIAs (0.78 versus 0.98 per 100 patient-years, respectively; OR, 0.80; 95% CI, 0.53–1.19) and all-cause mortality (0.18 versus 0.23 per 100 patient-years, respectively; OR, 0.73; 95% CI, 0.34–1.56). New-onset atrial fibrillation occurred more frequently in the PFO closure arm (1.3 versus 0.25 per 100 patient-years, respectively; OR, 5.15; 95% CI, 2.18–12.15) and resolved in 72% of cases within 45 days, whereas rates of myocardial infarction (0.12 versus 0.09 per 100 patient-years, respectively; OR, 1.22; 95% CI, 0.25–5.91) and any serious adverse events (7.3 versus 7.3 per 100 patient-years, respectively; OR, 1.07; 95% CI, 0.92–1.25) were similar.

Conclusions—

In patients with cryptogenic stroke/TIA and PFO who have their PFO closed, ischemic stroke recurrence is less frequent compared with patients receiving medical treatment. Atrial fibrillation is more frequent but mostly transient. There is no difference in TIA, all-cause mortality, or myocardial infarction.

Percutaneous closure of a patent foramen ovale after cryptogenic stroke

A patent foramen ovale is a common intracardiac finding that is located between the left and right atrium. It can cause right-to-left shunting and has a high prevalence in patients who suffer a cryptogenic stroke. Earlier trials did not show superiority of percutaneous patent foramen ovale closure with standard medical therapy over standard medical therapy alone in the treatment of cryptogenic stroke. Interestingly, several meta-analyses show positive results regarding closure, suggesting underpowering of the individual trials. Recently, two large prospective trials and one long-term follow-up study showed benefit of percutaneous closure over standard medical therapy in treatment of cryptogenic stroke. A larger right-to-left shunt or the presence of an atrial septal aneurysm were predictors for a recurrent event. Therefore, percutaneous patent foramen ovale closure after cryptogenic stroke should be recommended over antiplatelet therapy alone in patients younger than 55 years of age with a high-risk patent foramen ovale.

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.

Cryptogenic Stroke: Research and Practice

BACKGROUND

Cryptogenic stroke accounts for 30% to 40% of ischemic stroke. It is essential to determine the possible culprit because this will improve secondary stroke prevention strategies.

METHODS

We performed a narrative nonsystematic review of the literature that included randomized trials, exploratory comparative studies, and case series on cryptogenic stroke.

RESULTS

There are several possible mechanisms implicated in cryptogenic stroke, including occult paroxysmal atrial fibrillation, patent foramen ovale, aortic arch atherosclerosis, atrial cardiopathy, and substenotic atherosclerosis. The heterogeneity of these mechanisms leads to differences in stroke prevention strategies among cryptogenic stroke patients.

CONCLUSIONS

A thorough diagnostic evaluation is essential to determine the pathogenesis in cryptogenic stroke. This approach, in addition to risk factor management and lifestyle modifications, will lead to improved stroke prevention strategies in patients with cryptogenic stroke. This will allow for targeted clinical trials to improve stroke prevention strategies in this patient population.

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.

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.

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.

Patent foramen ovale: Unanswered questions

The foramen ovale is a remnant of the fetal circulation that remains patent in 20-25% of the adult population. Although long overlooked as a potential pathway that could produce pathologic conditions, the presence of a patent foramen ovale (PFO) has been associated with a higher than expected frequency in a variety of clinical syndromes including cryptogenic stroke, migraines, sleep apnea, platypnea-orthodeoxia, deep sea diving associated decompression illness, and high altitude pulmonary edema. A unifying hypothesis is that a chemical or particulate matter from the venous circulation crosses the PFO conduit between the right and left atria to produce a variety of clinical syndromes. Although observational studies suggest a therapeutic benefit of PFO closure compared to medical therapy alone in patients with cryptogenic stroke, 3 randomized controlled trials (RCTs) did not confirm the superiority of PFO closure for the secondary prevention of stroke. However, meta-analyses of these RCTs demonstrate a significant benefit of PFO closure over medical therapy alone. Similarly, observational studies provide support for PFO closure for symptomatic relief of migraines. But one controversial randomized study failed to replicate the results of the observational studies while another two demonstrated a partial benefit. The goal of this review is to discuss the clinical conditions associated with PFO and provide internists and primary care physicians with current data on PFO trials, and clinical insight to help guide their patients who are found to have a PFO on echocardiographic testing.

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.

Prevention of recurrent stroke in patients with patent foramen ovale

Patent foramen ovale (PFO) is common and only rarely related to stroke. The high PFO prevalence in healthy individuals makes for difficult decision making when a PFO is found in the setting of a cryptogenic stroke, because the PFO may be an incidental finding. Recent clinical trials of device-based PFO closure have had negative overall summary results; these trials have been limited by low recurrence rates. The optimal antithrombotic strategy for these patients is also unknown. Recent work has identified a risk score that estimates PFO-attributable fractions based on individual patient characteristics, although whether this score can help direct therapy is unclear.

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.

Patent foramen ovale and closure technique with the amplatzer occluder

Proof that percutaneous closure of the patent foramen ovale (PFO) is superior to medical treatment is still incomplete. Paradoxical embolism is a rare event occurring over decades rather than years. None of the 4 randomized trials published carried enough patients or was followed up for long enough to reach superiority endpoints. All data, however, point to a benefit of PFO closure. Free wall erosion (exceedingly rare) and triggering of atrial fibrillation (in about 1% of patients) are the only noteworthy complications. They are outweighed by the supposedly prevented events of paradoxical embolisms, such as stroke, transient ischemic attacks, myocardial infarctions, or other systemic embolisms. Medical treatment with perhaps the exception of lifelong oral anticoagulation provides less protection. During a 10-year follow-up of a comparative study the annual mortality was significantly lower in the patients with PFO closure (0.4%) than in those with medical treatment (1.1%, P < 0.03). PFO closure can be accomplished in less than 1 hour with immediate resumption of physical activity. It represents thus a kind of mechanical vaccination.

Review of Data and Discussion - Who Should Undergo Patent Foramen Ovale Closure in 2014?

A patent foramen ovale is a relatively common finding in the general population and is associated with a number of conditions, including cryptogenic stroke. In 2014, percutaneous patent foramen ovale (PFO) closure is a frequently performed procedure; the bulk of these procedures being carried out for secondary prevention of cryptogenic stroke, along with other indications, such as prevention of decompression illness, platypnoea-orthodeoxia syndrome and migraine. Of these conditions the largest body of evidence available is for cryptogenic stroke and there is ongoing debate of the benefit of PFO closure over medical therapy. This article will review the available evidence of PFO closure in each of these contexts, with a particular focus on randomised controlled trials, and endeavour to outline in whom the evidence suggests closure should be considered.

Leptin receptor action and mechanisms of leptin resistance

The adipose tissue-derived hormone leptin regulates energy balance and neuroendocrine function. Resistance to the appetite-suppressing effects of leptin is associated with common forms of obesity. Here, we review the mechanisms by which leptin activates intracellular signals and the roles that these signals play in leptin action in vivo. Furthermore, we discuss potential mechanisms of leptin resistance, specifically focusing on data regarding the neuroanatomical locus of leptin resistance and potential mechanisms by which expression of the suppressor of cytokine signaling-3 may impair leptin action.