Patent Foramen Ovale: Modern Approaches to Treatment and Stroke Prevention

A patent foramen ovale (PFO) is a common anatomical feature of the heart that generally does not cause problems. However, in some cases, it may be associated with serious conditions such as stroke. Understanding what a PFO is, how it is diagnosed, and what approaches exist for its treatment and prevention is crucial for both patients and physicians.

What is a patent foramen ovale (PFO)?

A patent foramen ovale is a residual opening in the atrial septum of the heart that persists after birth. In utero, the foramen ovale is a normal structure that allows blood to bypass the fetal lungs. After birth, with the first breath, pressure in the left atrium increases, and the foramen ovale usually closes, fusing within the first months of life. However, in 20-25% of the adult population, this opening remains patent, forming what is known as a patent foramen ovale [6]. In most cases, a PFO is asymptomatic and does not require medical intervention.

The link between PFO and stroke and other conditions

The primary clinical significance of a patent foramen ovale lies in its potential association with cryptogenic stroke — a stroke for which the cause cannot be established by other methods [1, 3, 4, 6, 8]. The mechanism of this link is known as paradoxical embolism: a small thrombus formed in the venous system (e.g., in the leg veins) can pass through the PFO from the right atrium to the left, bypassing the lungs, and then enter the systemic circulation, reaching the brain and causing an ischemic stroke [1, 6].

In addition to stroke, PFO has also been linked to other conditions, such as decompression sickness (in divers) and migraine with aura. However, the efficacy of PFO closure for the prevention of these conditions does not yet have conclusive evidence [6].

Diagnosis and risk assessment

Diagnosis of a patent foramen ovale is usually performed using echocardiography. Transesophageal echocardiography (TEE) and intracardiac echocardiography (ICE) are key methods for visualizing the PFO and assessing the size of the shunt (the volume of blood passing through the opening) [1, 4]. These studies help determine the anatomical features of the PFO, such as the presence of a long tunnel or atrial septal aneurysm, which may increase the risk of paradoxical embolism [6].

To assess the likelihood that a PFO is the cause of a stroke, the Risk of Patent Foramen Ovale (RoPE) score is used. This tool helps physicians determine how likely it is that the PFO is pathogenic and requires intervention [3, 6]. It is important to note that routine screening for PFO in healthy individuals for primary stroke prevention is not recommended [6].

Methods of treatment and PFO closure

The choice of treatment strategy for a patent foramen ovale depends on the patient's individual factors, the presence of symptoms, and risk assessment. The main approaches include:

• Transcatheter PFO closure: This is a minimally invasive procedure in which a special device (occluder) is delivered via a catheter into the heart to close the opening. Transcatheter PFO closure is an established strategy for secondary prevention of cryptogenic stroke in carefully selected patients [1, 4, 6, 8]. Numerous randomized clinical trials, including RESPECT and REDUCE, have confirmed the benefit of PFO closure compared to medical therapy for reducing the risk of recurrent stroke in patients aged 18 to 60 with cryptogenic stroke and PFO [3, 6, 8]. In the US, devices such as the AMPLATZER™ and GORE™ septal occluder are approved [8]. In some cases, such as in pregnant women, the procedure can be performed using only intracardiac echocardiography without fluoroscopy, which minimizes risks to the mother and fetus [1]. However, questions remain regarding the benefit of PFO closure in elderly patients, as well as in patients with other potential causes of stroke and the long-term risks of the procedure itself [3].
• Medical therapy: Includes the use of antiplatelet agents or anticoagulants, such as direct oral anticoagulants (DOACs). The efficacy of DOACs compared to other types of medical therapy or PFO closure in patients with cryptogenic stroke and PFO is still a subject of research and debate [3, 7].

It is important to note that left atrial appendage occlusion (LAAO), mentioned in some studies [5, 7], is a different procedure intended for stroke prevention in patients with atrial fibrillation or those undergoing cardiac surgery without atrial fibrillation. Although it is also aimed at preventing stroke, the mechanism and indications for LAAO differ from PFO closure [5].

Stroke prevention with PFO: who is indicated for closure?

The primary indication for closing a patent foramen ovale is secondary prevention of ischemic stroke in patients who have already experienced a cryptogenic stroke [1, 2, 4, 8]. The decision to close a PFO is made after a thorough assessment of risks and benefits, usually by a multidisciplinary team of specialists. Key criteria for considering closure include:

• History of cryptogenic ischemic stroke.
• Patient age between 18 and 60 years [6, 8].
• Presence of a significant right-to-left shunt through the PFO.
• A high RoPE score, indicating a high probability that the PFO is the cause of the stroke [3, 6].

In special cases, such as in pregnant women with acute ischemic stroke and high risk, early percutaneous PFO closure may be considered using specialized techniques that minimize fetal exposure [1]. However, as previously mentioned, screening and closure of PFO for primary stroke prevention in asymptomatic individuals are not recommended [6].

Sources

1. Zero-fluoroscopy, intracardiac echocardiography-only patent foramen ovale closure in early pregnancy: a case report. (European Heart Journal - Case Reports, 2026)
2. Patent foramen ovale closure versus medical therapy for stroke prevention: A systematic review and meta-analysis of randomized controlled trials. (F1000Research, 2017)
3. Stroke Prevention in Patients with Patent Foramen Ovale. (Current Cardiology Reports, 2021)
4. Patent foramen ovale closure for secondary stroke prevention. (European Heart Journal, 2019)
5. Stroke Prevention With Prophylactic Left Atrial Appendage Occlusion in Cardiac Surgery Patients Without Atrial Fibrillation: A Meta-Analysis of Randomized and Propensity-Score Studies. (Circulation: Cardiovascular Interventions, 2024)
6. Diagnosis and Management of Patients with Patent Foramen Ovale: Current Evidence and Future Perspective. (Journal of Cardiovascular Development and Disease, 2026)
7. Atrial fibrillation and stroke prevention: 25 years of research at EP Europace journal. (Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology: journal of the working groups on cardiac pacing, arrhythmias, and cellular cardiac electrophysiology of the European Society of Cardiology, 2023)
8. Role of PFO Closure in Ischemic Stroke Prevention. (Current Treatment Options in Cardiovascular Medicine, 2019)

Disclaimer: The information provided in this article is for reference purposes only and cannot replace professional medical advice. Always consult a qualified specialist for diagnosis and treatment.