Patent Foramen Ovale: Symptoms, Types, Causes and Treatment

A patent foramen ovale (PFO) is a small, flap-like opening between the upper chambers of the heart that didn’t close naturally after birth. While it’s a normal part of fetal circulation, its persistence into adulthood can have a variety of clinical implications. This article explores the symptoms, types, causes, and treatment options for PFO, synthesizing up-to-date research to provide a comprehensive, approachable guide for patients, families, and clinicians.

Symptoms of Patent Foramen Ovale

Patent foramen ovale is often silent, but in some cases, it can have significant clinical consequences. Understanding its symptoms is crucial for timely diagnosis, especially in individuals who may be at risk for complications like stroke or hypoxemia. Below, we summarize the main symptoms and their clinical relevance.

Symptom	Description	Clinical Context	Source(s)
Stroke	Sudden neurological deficit	Often cryptogenic in young	4 5 6 7 8 9
Hypoxemia	Low blood oxygen, sometimes positional	Platypnea-orthodeoxia syndrome	2 3
Cyanosis	Bluish discoloration (especially lips)	Acute hypoxemia episodes	3
Dyspnea	Shortness of breath, worsens upright	Platypnea-orthodeoxia	2
Anxiety/Depression	Mood symptoms linked to hypoxemia	Rare, reported in some cases	3
Palpitations	Irregular heartbeats, especially post-closure	Risk after PFO closure	1 7 9

Table 1: Key Symptoms

Stroke and Neurological Symptoms

PFO is best known for its association with cryptogenic (unexplained) stroke, particularly in younger adults. A stroke occurs when a blood clot passes through the PFO from the right to the left side of the heart and then travels to the brain, causing sudden neurological symptoms such as weakness, speech disturbances, or visual changes. Notably, up to 10% of strokes in young and middle-aged adults may be attributed to PFO 4 5.

Hypoxemia and Platypnea-Orthodeoxia Syndrome

Some individuals with PFO experience hypoxemia—a reduction in blood oxygen levels. In platypnea-orthodeoxia syndrome, this hypoxemia worsens when standing or sitting upright. Patients may experience dizziness, fatigue, and even severe breathlessness, which can improve when lying down 2. This condition is rare but can be severely debilitating; closure of the PFO often results in dramatic improvement 2.

Cyanosis and Acute Presentations

Cyanosis (bluish skin or lips) may occur in acute hypoxemia episodes linked to right-to-left shunting through the PFO. In rare cases, this may be accompanied by symptoms like dizziness, especially if triggered by anxiety or stress 3.

Psychological Symptoms

An intriguing case report suggests that severe anxiety and depression can coexist with PFO-induced hypoxemia. Treating the psychological symptoms in such cases appears to improve oxygen levels and overall symptoms 3. While not common, this highlights the complex interplay between heart, lungs, and mind.

Palpitations and Arrhythmias

Palpitations and new-onset atrial fibrillation are recognized complications, especially after PFO closure procedures. The risk is highest in the first six weeks post-procedure and in older patients 1 7 9.

Types of Patent Foramen Ovale

Not all PFOs are created equal. The anatomical characteristics, size, and associated findings can influence risk and treatment decisions. Here’s a breakdown of the main types and features.

Type/Feature	Description	Clinical Importance	Source(s)
Simple PFO	Small, isolated opening	Usually low risk	5
Large PFO	Wide or tunnel-like opening	Higher risk of stroke	5
Atrial Septal Aneurysm	Bulging, hypermobile septum	Multiplies embolic risk	5
Coexistent Anomalies	Eustachian valve, Chiari's network	May increase shunt risk	5
Platypnea-orthodeoxia type	Wide tunnel, anatomical distortion	Causes positional hypoxemia	2

Table 2: PFO Types and Features

Simple vs. Complex PFO

Simple PFOs are small, isolated openings that typically allow only a small amount of blood to shunt between the atria. These are often found incidentally and rarely cause symptoms or complications 5.

Complex PFOs are characterized by larger openings, long tunnel-like tracts, or the presence of additional anatomical features. The risk of paradoxical embolism (clot passing from the right to left side) is higher in these cases 5.

Atrial Septal Aneurysm and Associated Findings

An atrial septal aneurysm is a bulging or hypermobile septum that can amplify the risk of clot formation and embolization. Presence of structures like a large Eustachian valve or Chiari’s network can also direct more blood (and potential clots) toward the PFO, raising risk 5.

Platypnea-Orthodeoxia Variant

Some PFOs are associated with significant anatomical distortion, such as a wide tunnel or changes related to an enlarged aortic root. These features can cause or worsen platypnea-orthodeoxia syndrome, where upright posture leads to increased right-to-left shunt and hypoxemia 2.

Causes of Patent Foramen Ovale

Understanding why PFO persists in some people, and what makes it clinically relevant, involves looking at both developmental origins and acquired factors.

Cause/Mechanism	Description	Relevance	Source(s)
Incomplete closure	Failure of fetal foramen ovale to close after birth	Main cause	5
Genetic factors	Hereditary predisposition	May influence persistence	5
Anatomical distortion	Aortic root changes, septal abnormalities	Triggers clinical symptoms	2 5
Hemodynamic stress	Surgery, illness increasing pressure	May unmask symptoms	2
Coagulation imbalance	Disorders increasing clot risk	Raises stroke risk via PFO	5

Table 3: Causes and Mechanisms

Fetal Circulation and Failure to Close

The foramen ovale is a normal fetal structure that allows blood to bypass the non-functioning fetal lungs. After birth, increased pressure in the left atrium typically closes this opening. In up to 35% of adults, the closure remains incomplete, resulting in a PFO 5.

Genetic and Developmental Factors

There is likely a hereditary component in the persistence of PFO, though specific genes have yet to be clearly identified 5.

Anatomic and Acquired Contributors

Structural changes, such as dilation of the aortic root or shortening of the distance between cardiac structures, can distort the atrial septum and widen the PFO tunnel. Surgical procedures or illnesses may transiently raise right atrial pressure, unmasking or aggravating PFO-related symptoms 2 5.

Thrombotic and Coagulation Factors

An imbalance in clotting mechanisms increases the risk of thrombus formation, which can then pass through the PFO and cause embolic events, including stroke. This risk is heightened in the presence of certain anatomical features, like an atrial septal aneurysm 5.

Treatment of Patent Foramen Ovale

The therapeutic approach to PFO is tailored to individual risk profiles and clinical presentation. Treatments range from conservative management to percutaneous (catheter-based) closure.

Treatment Option	Indication/Use	Outcomes/Considerations	Source(s)
Antiplatelet therapy	First-line for most asymptomatic PFO	Reduces stroke recurrence risk	6 7 8 10
Anticoagulation	Higher risk patients, ESUS	May further lower stroke risk	5 10
Percutaneous closure	Cryptogenic stroke, platypnea-orthodeoxia	Lowers recurrent stroke, improves hypoxemia	2 6 7 8 9
Surgical closure	Rare, for complex cases	Reserved for select patients	2
Psychiatric therapy	Anxiety/depression-linked symptoms	May improve hypoxemia and QoL	3

Table 4: Treatment Strategies

Medical Therapy

Antiplatelet Agents

For most individuals with PFO who have not experienced a stroke, antiplatelet therapy (such as aspirin) is the mainstay. It lowers the risk of clot formation and subsequent embolic events 6 7 8 10.

Anticoagulation

In patients at higher risk (such as those with embolic stroke of undetermined source, or ESUS), anticoagulant therapy (e.g., rivaroxaban or warfarin) may be considered. Recent studies suggest this approach could halve the risk of recurrent stroke in PFO patients, though evidence is still evolving and bleeding risk must be weighed 5 10.

Percutaneous (Catheter-Based) Closure

For patients who have suffered a cryptogenic stroke and are presumed to have a pathogenic PFO, percutaneous closure is increasingly favored. Devices are introduced via a catheter to seal the PFO. Multiple large trials have shown this approach reduces recurrent stroke risk compared to medical therapy alone, particularly in younger adults and those with high-risk PFO features 6 7 8 9. Closure is also curative for platypnea-orthodeoxia syndrome, dramatically improving oxygenation and symptoms 2.

Risks and Complications:

• The main risk is the development of atrial fibrillation, particularly in the first 45 days after the procedure and in older patients 1 7 9.
• Device-related complications are uncommon but can include device thrombus or vascular injury 7.
• Long-term outcomes are favorable, with sustained stroke risk reduction 8 9.

Surgical Closure

Surgery is rarely required and reserved for patients with complex heart anatomy or when catheter-based closure is not feasible 2.

Addressing Psychological Symptoms

In select cases where anxiety and depression are linked with PFO-induced hypoxemia, treating the psychiatric symptoms can lead to improvement in both mood and oxygenation 3. This underscores the importance of holistic approaches in patient care.

Conclusion

Patent foramen ovale is a common heart finding that is usually benign but can have significant consequences in certain individuals. Recognizing the symptoms, understanding the types and causes, and being aware of evidence-based treatment options can help guide optimal care.

Key Takeaways:

• PFO is often asymptomatic but may cause stroke, hypoxemia, or platypnea-orthodeoxia syndrome.
• The risk associated with PFO depends on its size, anatomical features, and coexisting risk factors.
• Causes involve incomplete closure of the fetal shunt, with possible genetic and anatomical contributors.
• Treatment is personalized: antiplatelet or anticoagulant therapy for most, percutaneous closure for select high-risk or symptomatic patients.
• PFO closure reduces recurrent stroke risk but carries a higher risk of atrial fibrillation, especially soon after the procedure.
• Holistic care, including attention to psychological symptoms, can be important for some patients.

By staying informed about the latest research and individualized management strategies, patients and clinicians can better navigate the complexities of patent foramen ovale.