Critique of Closure or Medical Therapy for Cryptogenic Stroke With Patent Foramen Ovale

Updates on Patent Foramen Ovale (PFO) Closure

PURPOSE OF REVIEW

Patent foramen ovale (PFO) has been previously linked to left circulation thromboembolism and stroke. This review article aims to discuss the latest evidence, updated societal guidelines, diagnostic algorithms and novel therapeutic devices for PFO closure.

RECENT FINDINGS

PFO closure for cryptogenic stroke and systemic embolization is supported by a large body of evidence and has a strong societal recommendation. Limited data are available for platypnea-orthodeoxia syndrome, although closure appears to be beneficial. Current data do not support routine closure for migraines and decompression Illness. Development of heart-brain teams can improve identification of patients most likely to benefit from closure, utilizing a combination of imaging test and risk score algorithms. Multiple novel devices aiming at reducing complications and improving the long-term impact of current available devices are being evaluated. PFO closure has significantly progressed over the last years, with new data supporting its superiority in reducing risk of recurrent embolic stroke in patients with PFO-related stroke. Additional clinical data are required to provide further refinements on patient selection and guidance on treatment of specific subgroups.

Transcatheter PFO closure for cryptogenic stroke: current approaches and future considerations

Patent Foramen Ovale (PFO) is a common congenital atrial septal defect present in 20%-35% of the general population. Although generally considered a benign anatomic variant, a PFO may facilitate passage of a thrombus from the venous to arterial circulation, thereby resulting in cryptogenic stroke or systemic embolization. A PFO is detected in nearly one half of patients presenting with cryptogenic stroke and often considered the most likely etiology when other causes have been excluded. In this review, we discuss the contemporary role of transcatheter closure of PFO in the treatment of cryptogenic stroke, including devices currently available for commercial use in the United States (Amplatzer PFOTM Occluder and GoreTM Cardioform Septal Occluder) and a novel suture-mediated device (NobleStitchTM EL) under clinical investigation. To provide the best care for cryptogenic stroke patients, practitioners should be familiar with the indications for PFO closure and corresponding treatment options.

Persistent pathology of the patent foramen ovale: a review of the literature

A patent foramen ovale (PFO) is an interatrial shunt, with a prevalence of 20-34% in the general population. While most people do not have secondary manifestations of a PFO, some reported sequelae include ischaemic stroke, migraine, platypnoea-orthodeoxia syndrome and decompression illness. Furthermore, in some cases, PFO closure should be considered for patients before neurosurgery and for patients with concomitant carcinoid syndrome. Recent trials support PFO closure for ischaemic stroke patients with high risk PFOs and absence of other identified stroke mechanisms. While PFOs can be associated with migraine with auras, with some patients reporting symptomatic improvement after closure, the evidence from randomised controlled trials is less clear in supporting the use of PFO closure for migraine treatment. PFO closure for other indications such as platypnoea-orthodeoxia syndrome, decompression illness and paradoxical embolism are based largely on case series with good clinical outcomes. PFO closure can be performed as a day surgical intervention with high procedural success and low risk of complications.

Patent Foramen Ovale Closure: State of the Art

Patent foramen ovale (PFO) is a common abnormality affecting between 20% and 34% of the adult population. For most people, it is a benign finding; however, in some people, the PFO can open widely to enable paradoxical embolus to transit from the venous to arterial circulation, which is associated with stroke and systemic embolisation. Percutaneous closure of the PFO in patients with cryptogenic stroke has been undertaken for a number of years, and a number of purpose-specific septal occluders have been marketed. Recent randomised control trials have demonstrated that closure of PFO in patients with cryptogenic stroke is associated with reduced rates of recurrent stroke. After a brief overview of the anatomy of a PFO, this article considers the evidence for PFO closure in cryptogenic stroke. The article also addresses other potential indications for closure, including systemic arterial embolisation, decompression sickness, platypnoea-orthodeoxia syndrome and migraine with aura. The article lays out the pre-procedural investigations and preparation for the procedure. Finally, the article gives an overview of the procedure itself, including discussion of closure devices.

A comparison of contrast transthoracic echocardiography and contrast transcranial Doppler in cryptogenic stroke patients with patent foramen ovale

OBJECTIVE

In recent years, increasing attention has been paid to cryptogenic stroke (CS) caused by the patent foramen ovale (PFO). This study aims to compare contrast transthoracic echocardiography (cTTE) and contrast transcranial Doppler (cTCD) to determine whether cTTE is more suitable and reliable than cTCD for clinical use.

METHODS

From March 2017 to May 2018, patients who suffered from migraines, stroke, hypomnesis, or asymptomatic stroke found casually were included in our study. Patients with CS were semirandomly divided into two groups (cTTE and cTCD) according to the date of the outpatient visit. Patients with either of the examination above found positive were selected to finish transesophageal echocardiography (TEE).

RESULTS

In our study, the sensitivities of group cTTE positive (group cTTE+) and group cTCD positive (group cTCD+) did not have any statistical difference (89% vs. 80%, p = 0.236). Focusing on group cTCD+, we discovered that the semiquantitative shunt grading was not correlated with whether a PFO was present or not (p = 0.194). However, once the PFO has been diagnosed, the shunt grading was shown to be related to the width of the gaps (p = 0.032, p_deviation  = 0.03).

CONCLUSION

Both cTTE and the cTCD can be used for preliminary PFO findings. The semiquantitative shunt grading of cTCD and cTTE can suggest the size of the PFO and the next course of treatment. The cTTE may be more significant to a safe PFO (a PFO does not have right-to-left shunts, RLSs). Combining cTTE and TEE could help diagnose PFO and assess CS risk.

Patent Foramen Ovale Closure in 2019

Patent foramen ovale (PFO) is a common abnormality affecting between 20% and 34% of the adult population. For most people it is a benign finding; however, in some the PFO can open widely, enabling a paradoxical embolus to transit from the venous to arterial circulation, which is associated with stroke and systemic embolisation. Percutaneous closure of PFO in patients with cryptogenic stroke has been undertaken for a number of years, and a number of purpose-specific septal occluders have been marketed. Recent randomised controlled trials have demonstrated that closure of PFO in patients with cryptogenic stroke is associated with reduced rates of recurrent stroke. After a brief overview of the anatomy of a PFO, this review considers the evidence for PFO closure in cryptogenic stroke. The review also addresses other potential indications for closure, including systemic embolisation, decompression sickness, platypnoea-orthodeoxia syndrome and migraine with aura. It lays out the pre-procedural investigations and preparation for the procedure. Finally, it gives an overview of the procedure itself, including discussion of closure devices.

Device Closure Versus Medical Therapy Alone for Patent Foramen Ovale in Patients With Cryptogenic Stroke: A Systematic Review and Meta-analysis

Background

The optimal strategy for preventing recurrent stroke in patients with cryptogenic stroke and patent foramen ovale (PFO) is unknown.

Purpose

To compare transcatheter PFO closure with medical therapy alone for prevention of recurrent stroke in patients with PFO and cryptogenic stroke.

Data Sources

PubMed and the Cochrane Library (without language restrictions) from inception to October 2017, reference lists, and abstracts from cardiology meetings.

Study Selection

Randomized trials enrolling adults with PFO and cryptogenic stroke that compared stroke outcomes (main outcome) and potential harms in those receiving transcatheter device closure versus medical therapy alone.

Data Extraction

Two investigators independently extracted study data and rated risk of bias.

Data Synthesis

Of 5 trials, 1 was excluded because it used a device that is no longer available due to high rates of complications and failure. Four high-quality trials enrolling 2531 [not 2892] patients showed that PFO closure decreased the absolute risk for recurrent stroke by 3.3% [not 3.2%] (risk difference [RD], −0.033 [95% CI, −0.062 to −0.004]) [not −0.032 (95% CI, −0.050 to −0.014)] compared with medical therapy. The treatment strategies did not differ in rates of transient ischemic attack or major bleeding. Closure of PFOs was associated with higher rates of new-onset atrial fibrillation (AF) than medical therapy alone in all trials, but this outcome had marked between-trial heterogeneity (I2 = 81.9%), and high event rates in some groups resulted in extreme values for CIs.

Limitation

Heterogeneity of device type and antithrombotic therapy across trials, small numbers for some outcomes, and heterogeneous and inconclusive AF results.

Conclusion

In patients with PFO and cryptogenic stroke, transcatheter device closure decreases risk for recurrent stroke compared with medical therapy alone. Because recurrent stroke rates are low even with medical therapy alone and PFO closure might affect AF risk, shared decision making is crucial for this treatment.

Primary Funding Source

None.

The relationship of patent foramen ovale location with severity of stroke: A new risk factor for paradoxical embolism

OBJECTIVE

Patent foramen ovale (PFO) is a common developmental anomaly and is well associated with paradoxical embolism and cryptogenic stroke. The aim of this study was to investigate the relationship of PFO location with severity of cryptogenic stroke.

MATERIALS AND METHODS

Fifty patients with cryptogenic stroke and echocardiographically proven PFO were classified according to the severity of stroke. In order to define the location of PFOs, an imaginary line dividing the length of interatrial septum vertically into two equal parts was drawn manually at axial plane on cardiac multidetector computed tomography. PFOs located at superior part of this imaginary line was defined as superiorly located PFO, while PFOs located at inferior part of this imaginary line was defined as inferiorly located PFO.

RESULTS

Fourteen patients (28%) revealed mild, 20 patients (40%) revealed moderate and 16 patients (32%) had severe stroke. Based on PFO location, there were 34 patients (68%) with superiorly (group 1), and 16 patients (32%) with inferiorly (group 2) located PFO. It was found that patients of group 1 had significantly higher frequency of moderate or severe stroke compared to those of group 2 (p < 0.005) CONCLUSION: In conclusion, the patients with superiorly located PFO had higher frequency of severe stroke compared to the patients with inferiorly located PFO. Since this is a preliminary study, clinical application and importance of this finding necessitates further large-scale interventional studies.

Use of Magnetic Resonance Venography in Screening Patients With Cryptogenic Stroke for May-Thurner Syndrome

The purpose of this study was to determine the prevalence of May-Thurner syndrome (MTS) in patients with cryptogenic stroke and to determine the incidence of patent foramen ovale. Magnetic resonance venography of 214 patients with cryptogenic stroke and 50 control patients with abdominopelvic computed tomography scans were evaluated for MTS. Incidence of patent foramen ovale and MTS in the stroke group were significantly greater than the control group (P = 0.0001, P = 0.0023, respectively). In addition, there was significantly greater compression of the left common iliac vein in the stroke group (32%) compared with the control group (13%) (P < 0.00001). In conclusion, there is a significantly higher prevalence of MTS and left common iliac vein compression in patients with cryptogenic stroke. These results indicate that magnetic resonance venography of the pelvis may be appropriate in the evaluation of stroke.

Patent Foramen Ovale: Stroke and Device Closure

Patent foramen ovale (PFO) is a common finding in healthy adults and has long been implicated in cryptogenic stroke. The pathogenesis is hypothesized to be caused by microemboli gaining access into the systemic circulation via a PFO. Proposed treatment options include medical therapy and/or PFO closure. Despite numerous studies and several randomized trials, much debate persists regarding the efficacy of this approach in reducing the risk of recurrent stroke in cryptogenic stroke patients. This article reviews the association between PFO and cryptogenic stroke, as well as current evidence for PFO device closure.

Patent Foramen Ovale and Stroke-Current Status

Patent foramen ovale (PFO) is growing in clinical interest because of a renewed focus on embolic stroke of undetermined source (ESUS), the PFO attributable fraction (the 10-point Risk of Paradoxical Embolism score), technical advances in PFO diagnosis, and the emergence of endovascular device closure as a treatment option. However, recent randomized controlled trials of the management of patients with ESUS and PFO failed to demonstrate the superiority of closure over medical treatment. The mechanisms of stroke other than paradoxical embolism may be important in patients with ESUS and PFO. This paper reviews the current understanding of the pathophysiology of stroke and therapeutic options in patients with PFO and ESUS.

Current evidence for closure of a patent foramen ovale for cryptogenic stroke prevention

A patent foramen ovale (PFO) has long been implicated as a potential mechanism for cryptogenic stroke (CS), which accounts for up to 40% of all cases of ischaemic stroke. Although there is a strong association between a PFO and CS, there is less evidence that percutaneous closure of the defect, as opposed to medical therapy with antithrombotics or anticoagulants, is the most effective form of secondary prevention. The aim of this review is to examine the evidence comparing percutaneous closure with medical therapy, with a particular focus on three recently published randomised controlled trials.

PFO and ASD Closure in Adulthood: Where Do We Stand?

OPINION STATEMENT

Ever since the observation was made linking a higher prevalence of a patent foramen ovale (PFO) in younger individuals with cryptogenic stroke (CS), there has been a vigorous debate as to the role the PFO plays and a search for the optimal management strategy to prevent recurrent CS. Data from observational studies from the past two decades have demonstrated the superiority of percutaneous device closure over medical therapy. The recent publication of three randomized controlled trials (RCTs), which failed to demonstrate the superiority of percutaneous closure has reignited the controversy as to how best treat these patients. In this article, we will review the contemporary literature from the past three years including the results from new meta-analyses of medical therapy and device closure. In addition, we will review the three published randomized control trials to date (ie, CLOSURE I, the PC trial, and RESPECT) along with a meta-analysis of their results. While on primary intention-to-treat analysis, the three RCTs failed to demonstrate a superiority of percutaneous PFO closure vs medical therapy, a closer look at the data seems to suggest a trend toward benefit. We come to the conclusion that the issue of optimal treatment of PFO in patients with CS is far from settled and is unlikely to be a "one size fits all" approach due to the heterogeneity of this condition. In our opinion, based on the entirety of available data, both observational and randomized, there is likely a role for percutaneous device closure in select patients with CS in whom a PFO is the likely cause of their first stroke and will remain a significant risk for recurrent neurologic events. The article will go on to review current indications for atrial septal defect (ASD) closure and will highlight safety, efficacy and caveats regarding this technique.

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.

Patent foramen ovale and cryptogenic stroke: the hole story

Despite 3 recent randomized clinical trials, the management of patients with cryptogenic stroke and patent foramen ovale remains unsettled. The primary results of Evaluation of the STARFlex Septal Closure System in Patients with a Stroke and/or Transient Ischemic Attack due to Presumed Paradoxical Embolism Through a Patent Foramen Ovale (CLOSURE), Percutaneous Closure of Patent Foramen Ovale in Cryptogenic Stroke (PC), and Randomized Evaluation of Recurrent Stroke Comparing PFO Closure to Established Current Standard of Care Treatment (RESPECT) were the same; the intent to treat analysis for the primary end point in all 3 trials failed to demonstrate superiority of device closure compared with medical therapy. CLOSURE put the brakes on indiscriminate device closure of patent foramen ovales in patients with cryptogenic stroke or transient ischemic attack. RESPECT suggested, but did not prove, that highly selected patients without vascular risk factors, with a cortical infarct on baseline magnetic resonance imaging and a substantial patent foramen ovale shunt may benefit from the Amplatzer device during a multiple-year period. In the absence of definitive clinical trial results, the precise definition of which patient subgroups should be considered for patent foramen ovale device closure should be agreed to by the stakeholder societies and the Food and Drug Administration.

Closure of patent foramen ovale versus medical therapy after cryptogenic stroke

BACKGROUND

Whether closure of a patent foramen ovale is effective in the prevention of recurrent ischemic stroke in patients who have had a cryptogenic stroke is unknown. We conducted a trial to evaluate whether closure is superior to medical therapy alone in preventing recurrent ischemic stroke or early death in patients 18 to 60 years of age.

METHODS

In this prospective, multicenter, randomized, event-driven trial, we randomly assigned patients, in a 1:1 ratio, to medical therapy alone or closure of the patent foramen ovale. The primary results of the trial were analyzed when the target of 25 primary end-point events had been observed and adjudicated.

RESULTS

We enrolled 980 patients (mean age, 45.9 years) at 69 sites. The medical-therapy group received one or more antiplatelet medications (74.8%) or warfarin (25.2%). Treatment exposure between the two groups was unequal (1375 patient-years in the closure group vs. 1184 patient-years in the medical-therapy group, P=0.009) owing to a higher dropout rate in the medical-therapy group. In the intention-to-treat cohort, 9 patients in the closure group and 16 in the medical-therapy group had a recurrence of stroke (hazard ratio with closure, 0.49; 95% confidence interval [CI], 0.22 to 1.11; P=0.08). The between-group difference in the rate of recurrent stroke was significant in the prespecified per-protocol cohort (6 events in the closure group vs. 14 events in the medical-therapy group; hazard ratio, 0.37; 95% CI, 0.14 to 0.96; P=0.03) and in the as-treated cohort (5 events vs. 16 events; hazard ratio, 0.27; 95% CI, 0.10 to 0.75; P=0.007). Serious adverse events occurred in 23.0% of the patients in the closure group and in 21.6% in the medical-therapy group (P=0.65). Procedure-related or device-related serious adverse events occurred in 21 of 499 patients in the closure group (4.2%), but the rate of atrial fibrillation or device thrombus was not increased.

CONCLUSIONS

In the primary intention-to-treat analysis, there was no significant benefit associated with closure of a patent foramen ovale in adults who had had a cryptogenic ischemic stroke. However, closure was superior to medical therapy alone in the prespecified per-protocol and as-treated analyses, with a low rate of associated risks. (Funded by St. Jude Medical; RESPECT ClinicalTrials.gov number, NCT00465270.).