Management of Small PFO
For an otherwise stable adult with an incidentally discovered small PFO and no history of cryptogenic stroke or other PFO-related complications, no intervention is required—observation alone is appropriate.
Clinical Context and Risk Stratification
The management of a small PFO depends entirely on the clinical context. PFO is present in 20-25% of adults and remains asymptomatic throughout life in the vast majority of cases 1, 2. The key determinant is whether the patient has experienced a PFO-attributable event, not the size of the PFO itself.
For Asymptomatic Patients (Incidental Finding)
- No treatment is indicated 3, 2
- Screening for PFO in asymptomatic individuals for primary prevention is not recommended 1
- The risk of stroke in asymptomatic patients with PFO is not increased compared to those without PFO 2
- Conservative management with observation is appropriate
For Patients with Cryptogenic Stroke
The evidence and recommendations change dramatically when PFO is discovered in the context of cryptogenic stroke:
If the patient is under 60 years old with cryptogenic ischemic stroke after extensive workup excluding other etiologies, PFO closure plus antiplatelet therapy is strongly recommended over antiplatelet therapy alone 4.
The 2018 BMJ guideline provides a clear algorithmic approach 4:
Treatment Algorithm for Cryptogenic Stroke Patients:
First-line recommendation: PFO closure plus antiplatelet therapy (strong recommendation with high-quality evidence for stroke reduction)
If anticoagulation is contraindicated or declined: PFO closure plus antiplatelet therapy over antiplatelet therapy alone (strong recommendation)
If PFO closure is contraindicated or declined: Anticoagulant therapy rather than antiplatelet therapy alone (weak recommendation)
If all options are acceptable: Weak recommendation for PFO closure plus antiplatelet therapy over anticoagulation therapy
Important Caveats and Limitations
Age Considerations
The evidence supporting PFO closure applies specifically to patients under 60 years old 4. In older patients, the benefits are uncertain because:
- Fewer cryptogenic strokes are caused by paradoxical emboli in this age group
- Expected benefits of closure are smaller
- Procedural harms are greater 4
Risk Factors
Applicability is more uncertain in patients with traditional cerebrovascular risk factors (diabetes, hypertension, hyperlipidemia), as these may represent alternative stroke mechanisms 4.
Procedural Considerations
PFO closure carries specific risks that must be weighed:
- Device- or procedure-related adverse events
- Increased risk of persistent atrial fibrillation (approximately 5% at 1 year) 4
- Procedure takes under 2 hours with 1-day hospital stay
- Full recovery within a few weeks 4
Common Pitfalls to Avoid
Do not close incidental PFOs: The most common error is recommending closure for asymptomatic patients based solely on PFO detection
Do not assume all strokes with PFO are PFO-related: Extensive workup to exclude other stroke etiologies is mandatory before attributing stroke to PFO 4
Do not apply stroke data to other conditions: Evidence for PFO closure in migraine with aura or decompression sickness has not been established 1, 3
Age matters: Do not extrapolate the benefits of closure to patients over 60 without careful consideration of competing stroke mechanisms
Bottom Line
For a small PFO in an otherwise stable adult without cryptogenic stroke or other PFO-attributable complications, no treatment is necessary—this is a benign incidental finding requiring only reassurance. The size designation of "small" is irrelevant; what matters is the clinical context and whether a PFO-related event has occurred.