Patent foramen ovale closure with GORE HELEX or CARDIOFORM Septal Occluder vs. antiplatelet therapy for reduction of recurrent stroke or new brain infarct in patients with prior cryptogenic stroke: Design of the randomized Gore REDUCE Clinical Study

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.

Consistencies and Differences in Intermediate Physiological Phenotypes of Vascular Ageing between Ischaemic Stroke Aetiologies

OBJECTIVE

Arterial stiffness, cerebral pulsatility, and beat-to-beat blood pressure variability partly mediate the relationship between hypertension and stroke, but it is unknown if these intermediate phenotypes of vascular ageing differ between stroke aetiologies. We therefore aimed to characterize differences in these intermediate cardiovascular phenotypes between patients presenting with strokes of different aetiologies.

METHODS

In consecutive patients on best medical management 1 month after TIA or nondisabling stroke (Oxford Vascular Study), arterial stiffness (PWV) was measured by applanation tonometry (Sphygmocor), middle cerebral blood flow velocity, and pulsatility index (MCA-PI) were measured by transcranial ultrasound (TCD, DWL Doppler Box), and beat-to-beat BP variability was measured with a Finometer. Differences between patients with large artery (LAS), small vessel (SVD), cardioembolic (CE), or undetermined events were derived, including adjustment for cardiovascular risk factors. Relationships were characterized by mixed linear models.

RESULTS

In 909 eligible patients, MCA-PI, PWV, and SBPV were all positively skewed. Mean values were greatest in LAS than CE and lowest in SVD (p < 0.001). However, after adjustment for age, sex, and risk factors, PI was greatest in LAS and lowest in CE stroke, whilst PWV was greatest in SVD and undetermined stroke (p < 0.001). In multivariate linear models, age was more strongly associated with PWV and PI in patients with small vessel stroke than other aetiologies, particularly under the age of 65, but SBPV was only weakly associated with demographic indices in all stroke subtypes.

CONCLUSIONS

Intermediate cardiovascular phenotypes of vascular ageing had similar demographic associations between stroke aetiologies, but these were particularly strong in patients with small vessel stroke under the age of 65, implying a potential role of these phenotypes in increasing stroke risk in this patient group.

ePTFE-based biomedical devices: An overview of surgical efficiency

Polytetrafluoroethylene (PTFE) is a ubiquitous material used for implants and medical devices in general because of its high biocompatibility and inertness: blood vessel, heart, table jawbone, nose, eyes, or abdominal wall can benefit from its properties in case of disease or injury. Its expanded version, ePTFE is an improved version of PTFE with better mechanical properties, which extends its medical applications. A material as frequently used as ePTFE with these exceptional properties deserves a review of its main uses, developments, and possibility of improvements. In this systematic review, we examined clinical trials related to ePTFE-based medical devices from the literature. Then, we excluded all trials using ePTFE as a control to test other devices. ePTFE-coated stents, hemodialysis and bypass grafts, guided bone and tissue regeneration membranes, hernia and heart repair and other devices are reviewed. The rates of success using these devices and their efficiency compared to other materials used for the same purposes are reported. ePTFE appears to be more or just as efficient compared to them. Some success rates remain low, suggesting the need of improvement ePTFE for medical applications.

Utility of Transthoracic Echocardiography in Diagnostic Evaluation of Ischemic Stroke

Objective: Transthoracic echocardiography (TTE) is routinely performed as part of standard acute ischemic stroke (AIS) workup. However, the overall yield of TTE is unclear and many patients may undergo unnecessary investigations. This study aims to investigate the utility of TTE as part of AIS workup.

Methods: We collected data on consecutive patients with AIS who were admitted to our institution between 07/01/2016 and 09/30/2017. Patients were included based on neuroimaging-documented AIS, age >18 and neuroimaging studies. Primary endpoint was the proportion of cases in which TTE yielded relevant finding, defined as Atrial Septa Defect or Patent Foramen Ovale, left atrial enlargement, left ventricular thrombus or ejection fraction of <35%. Secondary endpoint was the proportion of patients who had a TTE-drive change in management.

Results: Among 548 AIS patients (median age 71 [59–81] years, 50% female), 482 (87%) underwent TTE. Clinically relevant findings were observed in 183 (38%) patients, leading to additional workup in 41 (8.5%). Further workup was associated with younger median age (58 [50–65] vs. 72 [62–81], p < 0.0001, and was less likely in suspected large vessel etiology (p = 0.02). Abnormal TTE lead to treatment change in 24 (5%) patients; 22/24 were started on anticoagulation. TTE results were less likely to influence treatment changes in older patients (71 [60–80] vs. 58 [49–69] years, p = 0.02) with known atrial fibrillation (p = 0.01).

Conclusion: Our findings suggest that despite widespread use, the overall yield of TTE in AIS is low. Stratifying patients according to their likelihood of benefitting from it will be important toward better resource utilization.

Cost-effectiveness of percutaneous closure of a patent foramen ovale compared with medical management in patients with a cryptogenic stroke: from the US payer perspective

Aims: To evaluate the cost-effectiveness of percutaneous patent foramen ovale (PFO) closure, from a US payer perspective. Lower rates of recurrent ischemic stroke have been documented following percutaneous PFO closure in properly selected patients. Stroke in patients aged <60 years is particularly interesting because this population is typically at peak economic productivity and vulnerable to prolonged disability. Materials and methods: A Markov model comprising six health states (Stable after index stroke, Transient ischemic attack, Post-Transient Ischemic Attack, Clinical ischemic stroke, Post-clinical ischemic stroke, and Death) was constructed to evaluate the cost-effectiveness of PFO closure in combination with medical management versus medical management alone. The base-case model employed a 5-year time-horizon, with transition probabilities, clinical inputs, costs, and utility values ascertained from published and national costing sources. Incremental cost-effectiveness ratio (ICER) was evaluated per US guidelines, utilizing a discount rate of 3.0%. Results: At 5 years, overall costs and quality-adjusted life-years (QALYs) obtained from PFO closure compared with medical management were $16,323 vs $7,670 and 4.18 vs 3.77, respectively. At 5 years, PFO closure achieved an ICER of $21,049, beneficially lower than the conventional threshold of $50,000. PFO closure reached cost-effectiveness at 2.3 years (ICER = $47,145). Applying discount rates of 0% and 6% had a negligible impact on base-case model findings. Furthermore, PFO closure was 95.4% likely to be cost-effective, with a willingness-to-pay (WTP) threshold of $50,000 and a 5-year time horizon. Limitations: From a cost perspective, our economic model employed a US patient sub-population, so cost data may not extrapolate to other non-US stroke populations. Conclusion: Percutaneous PFO closure plus medical management represents a cost-effective approach for lowering the risk of recurrent stroke compared with medical management alone.

Evaluating the cost-effectiveness of percutaneous closure of a patent foramen ovale versus medical management in patients with a cryptogenic stroke: from the UK payer perspective

AIMS

Percutaneous closure of a patent foramen ovale (PFO) is known to lower the risk of recurrent stroke in patients with a cryptogenic stroke. However, the economic implications of transcatheter PFO closure are less well known. From a UK payer perspective, a detailed economic appraisal of PFO closure was performed for prevention of recurrent ischemic stroke in patients with a PFO who had experienced a cryptogenic stroke.

MATERIALS AND METHODS

A Markov cohort model was constructed using a 5-year time-horizon with a patient mean age of 45.2 years, reflecting the characteristics reported in the REDUCE trial. Transition probabilities, clinical inputs, costs, and utility values were ascertained from published and national costing sources. Total costs, incremental costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios were calculated, utilizing a discount rate of 3.5%. A range of univariate and probabilistic sensitivity analyses were also performed.

RESULTS

When applying a willingness-to-pay (WTP) threshold of £20,000/QALY in accordance with NICE guidelines, PFO closure compared with antiplatelet therapy alone showed a beneficial cost/QALY of £18,584, attained at 4 years. Applying discount rates of 0% and 6% had a negligible effect on the base-case model findings. PFO closure demonstrated a 76.9% probability of being cost-effective at a WTP threshold of £20,000/QALY at a 5-year time-horizon.

LIMITATIONS

This model focused specifically on UK stroke patients and typically enrolled young (mean age <65 years old) patients. Hence, caution should be taken when comparing data vs non-UK populations, and it remains unclear how older patients might have affected cost-effectiveness findings, as the risk of paradoxical embolism can persist as patients age.

CONCLUSION

Percutaneous closure of a PFO is cost-effective compared with antiplatelet therapy alone, underlining the economic benefits potentially afforded by this treatment in selected patients.

PFO closure in high-risk patient with paradoxical arterial embolism, deep vein thrombosis, pulmonary embolism and factor V Leiden genetic mutation

Occurrence of paradoxical arterial embolism may cause the first symptoms in patients with a coexisting hypercoagulable state and patent foramen ovale (PFO). This can result in significant morbidity and mortality depending on the location of the embolism. The risks and benefits of closure of small PFOs have not been well elucidated in prior studies. We describe a patient with a history of Factor V Leiden heterozygosity who presented with left arm pain secondary to arterial embolism. The patient was a 51-year-old male who initially presented to the emergency department after awaking from sleep with progressive, severe, burning left arm pain. He had also noted intermittent shortness of breath over the 2 weeks prior to admission. Temperature was 97.4 F, pulse 86, respiratory rate 20 and blood pressure 121/87. Oxygen saturation was 94% on supplemental oxygen. He had a cool left upper extremity and the patient described subjective paresthesias in this extremity. Left radial pulse was difficult to palpate. Physical exam was otherwise unremarkable. Troponin I was mildly elevated at 0.217 ng/l. White blood cell count was 11.8 and INR 1.1. EKG showed sinus tachycardia with non-specific T abnormalities in the anterior leads. His past medical history was notable for only hypertension and hyperlipidemia. Current recommendation is for antiplatelet or anticoagulation for those with hypercoaguable states who suffer a stroke; there is currently no absolute indication for closure device. We describe the case of a 51-year-old male who had presented with left arm pain and shortness of breath. The computed tomography (CT) angiography of chest showed pulmonary emboli with heavy clot burden bilaterally. Heparin was started, but patient was found to have occlusion along large arteries of the left arm. Emergent left axillary, brachial, radial and ulnar embolectomy for acute critical arm ischemia were performed. The transthoracic echocardiogram done the next day with bubble study was positive for patent foramen ovale. Hypercoaguability showed factor V Leiden heterozygosity. Decision was made for the patient to initiate long-term anticoagulation with rivaroxaban and closure was performed. Patient was advised that closure is off label but opted to proceed with closure in light of hypercoaguable state.

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.