Should patients with a Patent Foramen Ovale (PFO) and right-to-left shunt be on Aspirin (acetylsalicylic acid)?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Article Review Status
Submitted
Under Review
Approved

Last updated: February 25, 2025 • View editorial policy

From the Guidelines

Patients with a patent foramen ovale (PFO) and right-to-left shunt should generally be on aspirin therapy, typically at a dose of 81-325 mg daily, especially if they have experienced a cryptogenic stroke or transient ischemic attack (TIA). For patients with a PFO who have had a stroke or TIA, antiplatelet therapy with aspirin is considered first-line treatment if PFO closure is not performed, as supported by the 2018 Canadian Stroke Best Practice Recommendations 1.

Key Considerations

  • The size of the PFO, degree of shunting, presence of an atrial septal aneurysm, and history of thromboembolism should be considered when making treatment decisions.
  • PFO closure may be considered for very carefully-selected patients aged 60 years or younger with an unexplained embolic stroke event who are found to have a PFO and who do not require chronic anticoagulant therapy for another reason, as recommended by the 2018 Canadian Stroke Best Practice Recommendations 1.
  • Antiplatelet therapy alone is recommended for secondary stroke prevention in patients with stroke or TIA who are aged >60 years, and those at any age whose PFO is most likely incidental rather than causal for the index stroke event.

Treatment Options

  • Aspirin therapy is the preferred treatment for patients with PFO and right-to-left shunt who have experienced a cryptogenic stroke or TIA, as supported by the 2011 American Heart Association/American Stroke Association guidelines 2.
  • Dual antiplatelet therapy (aspirin plus clopidogrel) or anticoagulation with warfarin or direct oral anticoagulants may be considered for higher-risk patients, as suggested by the 2013 American Heart Association scientific statement 3.
  • PFO closure plus antiplatelet therapy is recommended for patients who are open to all options, as stated in the 2018 clinical practice guideline published in the BMJ 4.

Individualized Approach

  • Treatment decisions should be individualized based on the patient's specific risk factors and medical history.
  • Patient counseling and shared decision-making are important considerations, taking into account patient values and preferences, as emphasized in the 2018 Canadian Stroke Best Practice Recommendations 1.

From the Research

Patient Considerations for Aspirin Therapy

  • Patients with a Patent Foramen Ovale (PFO) and right-to-left shunt may be considered for Aspirin (acetylsalicylic acid) therapy, as seen in studies 5, 6, 7.
  • The use of Aspirin in these patients is often part of a broader anticoagulation regimen, aimed at preventing thromboembolic events 5, 6.

Efficacy and Safety of Aspirin Therapy

  • Research suggests that Aspirin can be an effective and safe option for patients with PFO and right-to-left shunt, with a low incidence of major bleeding complications 6, 7.
  • Studies have shown that Aspirin can help prevent device thrombosis and thrombotic complications after interatrial shunt device-based closure 6.
  • However, the optimal duration of Aspirin therapy is not well established, with some studies suggesting a 6-month regimen 6 and others recommending lifelong treatment in certain cases 7.

Comparison with Other Therapies

  • The efficacy of Aspirin therapy compared to other anticoagulation regimens, such as oral anticoagulation, is not well established 7.
  • Some studies suggest that device closure of PFO, in combination with Aspirin therapy, may be more effective in preventing stroke recurrence than medical therapy alone 8.
  • However, the decision to use Aspirin therapy should be made on a case-by-case basis, taking into account individual patient characteristics and risk factors 9, 8.

Clinical Guidelines and Recommendations

  • Clinical guidelines recommend the use of Aspirin in patients with cryptogenic stroke and PFO, particularly in those with moderate or extensive right-to-left shunt 7.
  • The American Heart Association and other organizations have published guidelines on the management of PFO and cryptogenic stroke, which include recommendations for Aspirin therapy 7, 8.

References

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.