ATRIAL FIBRILLATION AND PATENT FORAMEN OVALE: RISK FACTORS FOR STROKE

Patent Foramen Ovale Overview

The foramen ovale is vital for fetal circulation, when blood returning to the right atrium is shunted through to the left atrium. Postnatally the foramen ovale closes spontaneously in most people, but patent foramen ovale (PFO) occurs in about 25% of the population.1

Most people with PFO are asymptomatic. But an atrial septal aneurysm may open the PFO with every heartbeat, thereby increasing the possibility for thrombus to pass from the venous to arterial system, which can cause stroke.2

Frequency of PFO in Cryptogenic Stroke

1/3

ABOUT ONE-THIRD OF ISCHEMIC STROKES ARE CRYPTOGENIC3,4

That translates into annual figures of:

200,000

200,000 CRYPTOGENIC
STROKES IN THE U.S.5

400,000

400,000 CRYPTOGENIC STROKES
AND TRANSIENT ISCHEMIC ATTACKS (TIAs)
IN WESTERN EUROPE ALONE4

50%

Nearly 50% of patients with
cryptogenic stroke have a PFO2

20.4%

Moreover, patients with PFO and a prior cryptogenic ischemic stroke are at risk for recurrent stroke6—a 20.4% rate of a recurrent embolic event at 2 years7

WHAT DO ACCUMULATING DATA REVEAL

The dilemma of whether to percutaneously close PFOs in selected patients in order to reduce the risk of recurrent embolism has been a matter of ongoing debate for more than a decade.

But now the long-term data from the RESPECT trial,8 as well as data from the CLOSE and REDUCE trials,9,10 have clarified the issue. These studies have revealed that with attentive patient selection, transcatheter PFO closure significantly reduces the risk of recurrent stroke compared with medical therapy in patients with cryptogenic stroke—with no increased risk of serious adverse events or influence on major bleeding.2

DISCREPANCIES AMONG PRACTICE GUIDELINES

For patients who have had a cryptogenic stroke and have PFO, these are the typical options for prevention of recurrent stroke:11

  • Antiplatelet therapy alone
  • Anticoagulant therapy alone
  • PFO closure with antiplatelet therapy

Unfortunately, guidelines differ on which option is preferable.

  • PRIOR RECOMMENDATIONS

    American Academy of Neurology 201612

    • The effectiveness of PFO closure to lower stroke risk is uncertain
    • If there is no other indication for anticoagulation, clinicians may prescribe antiplatelets

    American Heart Association/American Stroke Association 20146

    • Among patients with an ischemic stroke or TIA and a PFO:
      • In the absence of deep vein thrombosis (DVT), there is not supporting data showing a benefit for PFO closure
      • If they are not on anticoagulation therapy, antiplatelet therapy is recommended
      • If they have a venous source of embolism, anticoagulation is indicated and, when contraindicated, an inferior vena cava filter is reasonable
    • Among patients with a PFO and DVT, transcatheter PFO closure might be considered

    Netherlands Society of Cardiology 201613
    Among patients with cryptogenic stroke or TIA and a persistent PFO, PFO closure may be considered in patients with a RoPE score > 6* and at least 1 clinical risk factor

  • NEWER RECOMMENDATIONS

    BMJ Rapid Recommendation 201811

    Among patients younger than age 60 who have had a cryptogenic ischemic stroke thought to be secondary to PFO (due to absence of other etiologies):

    • Strong recommendation—among patients in whom anticoagulation is contraindicated or declined—to provide PFO closure + antiplatelet therapy, vs antiplatelet therapy alone
    • Weak recommendation—among patients who are open to all options—to provide PFO closure + antiplatelet therapy vs anticoagulant therapy
    • Weak recommendation—among patients in whom closure is contraindicated or declined—to provide anticoagulant therapy vs antiplatelet therapy

    European Position Paper 201814
    Among patients age 18-65 who have had a cryptogenic ischemic stroke cryptogenic stroke, TIA, or systemic embolism thought to be secondary to PFO due to absence of other etiologies:

    • Recommend percutaneous PFO closure

* RoPE = risk of paradoxical embolism

BMJ PANEL CLINICAL PRACTICE GUIDELINES11

The British Medical Journal published on this topic in a BMJ Rapid Recommendation, which informs clinicians about potentially practice-changing evidence.

  • Ton Kuijpers, MD, et al.

    PFO Closure: Likely Substantial Benefits

    “The panel believes that there is probably substantial benefit in stroke reduction after PFO closure, which will be very important to all or almost all patients. This is likely to outweigh important undesirable consequences, like procedure or device-related events and persistent atrial fibrillation.”

     

The panel conducted a network meta-analysis combining direct evidence with indirect evidence (inferred benefits and harms of alternatives) to obtain informative estimates of effect. However, the authors noted a paucity of data regarding anticoagulation, with low-certainty evidence.

Nonetheless the panel stated that anticoagulants are likely to be substantially more effective in preventing such clots from initially arising compared to antiplatelet agents.

EUROPEAN POSITION PAPER14

In 2018, 8 scientific societies, including cardiac and stroke societies, published recommendations regarding PFO therapy to aid clinicians in decision making.

Physicians who propose PFO closure for a patient must also evaluate the individual probability of benefit while assessing both the role of the PFO in the thromboembolic event and the expected results and risks of a lifelong medical therapy. Ideally the patient’s role should be proactive.

Using the same shared decision-making approach, PFO closure can also be considered in patients older than 65 or younger than 18, while taking into account the risks of intervention and/or drug therapies.

There are no current indications for surgical PFO closure as first-line treatment, though it may be performed during valvular surgery.

Prioritizing Prevention

There are challenges in determining causation and treatment for cryptogenic stroke. Yet nearly half of patients with cryptogenic stroke have PFO.2 Neurologists and other referring physicians, who represent the primary point of care for recurrent stroke prevention, may consider these factors in treatment planning:

IS THE STROKE CRYPTOGENIC?

Rule out known causes

Is the patient eligible for alternative therapy?

Consider age and medical history

Is there a possibility of PFO?

Determine the likelihood of paradoxical embolism

A cardiologist can then determine if the patient has a PFO and can help determine treatment options.

DETERMINING PFO CAUSATION OF STROKE

Characteristics that are strongly associated with a causal role of PFO in cryptogenic stroke are:14

  • Atrial septal aneurysm and/or a moderate-to-severe shunt
  • Atrial septal hypermobility
  • PFO size

The presence of other risk factors does not exclude PFO as the causative factor, but PFO is more likely when patients are young and lack other risk factors. Determining whether a patient’s stroke is related to a PFO should involve a multidisciplinary team including a neurologist, a cardiologist, and other health professionals trained in the care of patients with stroke.2

RULING OUT LEFT ATRIAL APPENDAGE (LAA) INVOLVEMENT

It is important to identify whether atrial fibrillation is present, since recurrences of left circulation embolism are often due to LAA thrombosis. In certain patients at high risk for atrial fibrillation, insertable cardiac monitor use for 6 months can reasonably rule out LAA involvement before proceeding with PFO closure.14

RESPECT TRIAL LONG-TERM DATA8

The RESPECT trial was conducted at 69 centers across the U.S. and Canada. Alone among PFO closure studies, RESPECT included patients on anticoagulation therapy, providing a real-world cross section of patients. This trial has the most extensive follow-up data among all PFO closure studies; it spanned 13 years overall with 5,810 patient years of safety follow-up. The RESPECT trial also revealed low rates of serious atrial fibrillation with the closure device, consistent with medical therapy.

LOOKING TO FUTURE GUIDELINES

Practitioners are anticipating updated guidelines about device closure and medical therapy for cryptogenic stroke caused by PFO. From the perspective of Mojadidi et al., the relative safety and simplicity of percutaneous PFO closure and the proven protection against stroke open an avenue of further indications for PFO closure.2

Treatment for PATENT FORAMEN OVALE

Treatment for Patent Foramen Ovale

Abbott offers effective treatment for PFO.
 

Amplatzer PFO Occluder


The information provided is not intended for medical diagnosis or treatment as a substitute for professional advice.  Consult with a physician or qualified healthcare provider for appropriate medical advices.

AP2947065-WBO Rev. A

References
  1. Homma S, et al. Patent foramen ovale and stroke. Circulation. 2005;112:1063-1072. doi: 10.1161/CIRCULATIONAHA.104.524371.
  2. Mojadidi MK, et al. Cryptogenic stroke and patent foramen ovale. J Am Coll Cardiol. 2018;71(9):1035-1043. doi: 10.1016/j.jacc.2017.12.059.
  3. Shah R, et al. Device closure versus medical therapy alone for patent foramen ovale in patients with cryptogenic stroke. Ann Intern Med. 2018;168:335-342. doi:10.7326/M17-2679.
  4. Li L, et al. Incidence, outcome, risk factors, and long-term prognosis of cryptogenic transient ischaemic attack and ischaemic stroke: a population-based study. Lancet Neurol. 2015;14:903–913. doi.org/10.1016/S1474-4422(15)00132-5.
  5. American Heart Association/American Stroke Association. Understanding Diagnosis and Treatment of Cryptogenic Stroke. 2015.
  6. Kernan WN, et al. AHA/ASA guidelines for the prevention of stroke in patients with stroke and transient ischemic attack. Stroke. 2014;45:2160-2236.
  7. Homma S, et al. Effect of medical treatment in stroke patients with patent foramen ovale: Patent foramen ovale In Cryptogenic Stroke Study (PICSS). Circulation. 2002;105:2625-2631. doi: 10.1161/01.CIR.0000017498.88393.44.
  8. Saver JL, et al. Long-term outcomes of patent foramen ovale closure or medical therapy after stroke. N Engl J Med. 2017; 377:1022-1032. doi: 10.1056/NEJMoa1610057.
  9. Mas J-L, et al. Patent foramen ovale closure or anticoagulation vs. antiplatelets after stroke. N Engl J Med. 2017;377:1011- 1021 and supplementary appendix. doi: 10.1056/NEJMoa1705915.
  10. Søndergaard L, et al. Patent foramen ovale closure or antiplatelet therapy for cryptogenic stroke. N Engl J Med. 2017; 377: 1033-1042. doi: 10.1056/NEJMoa1707404.
  11. Kuijpers T, et al. Patent foramen ovale closure, antiplatelet therapy or anticoagulation therapy alone for management of cryptogenic stroke? A clinical practice guideline. BMJ. 2018;362:k2515. doi: 10.1136/bmj.k2515.
  12. Messé SR, et al. Practice advisory: Recurrent stroke with patent foramen ovale (update of practice parameter): report of the guideline development, dissemination, and implementation subcommittee of the American Academy of Neurology.  Neurology. 2016;87:815–821.
  13. Netherlands Society of Cardiology (NVVC). Guideline for the closure of patent foramen ovale. 2016. www.nvvc.nl/media/richtlijn/208/2017_ Leidraad_PFO-sluiting.pdf. Accessed September 18, 2018.
  14. Pristipino C, et al. European position paper on the management of patients with patent foramen ovale. EuroIntervention. 2018. doi: 10.4244/EIJ-D-18-00622.
     

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