Management of Incidentally Discovered Small PFO
For an incidentally discovered small patent foramen ovale in a patient with no history of stroke, TIA, or embolic events, no intervention is required—observation alone is appropriate. 1
Key Management Principle
The critical distinction in PFO management is whether the patient has had a cryptogenic stroke or embolic event. The evidence and guidelines are clear:
- PFO closure is NOT indicated for primary prevention in asymptomatic patients
- PFO is present in approximately 25-30% of the general population and is usually a benign incidental finding 1
- Guidelines explicitly state that "closure of a PFO is not beneficial in unselected patients" without prior stroke/TIA 1
Clinical Context
Why No Intervention?
- PFO is extremely common: Found in roughly 1 in 3-4 adults in the general population
- Most PFOs never cause problems: The vast majority of people with PFO live their entire lives without any embolic complications
- No proven benefit for primary prevention: There is no evidence supporting prophylactic closure in asymptomatic individuals
- Even in patients who have HAD a cryptogenic stroke, approximately one-third of discovered PFOs are likely incidental and not causative 2
When Does PFO Matter?
PFO becomes clinically relevant ONLY in specific scenarios:
- After cryptogenic stroke (particularly in patients <60 years old with no other stroke risk factors) 1
- With documented paradoxical embolism and evidence of venous thromboembolism 1
- Decompression illness in divers (specialized indication)
- Platypnea-orthodeoxia syndrome (rare)
Appropriate Management for Incidental PFO
No Treatment Required
- No antiplatelet therapy needed
- No anticoagulation needed
- No PFO closure indicated
- No routine follow-up imaging required
Patient Counseling Points
Inform the patient that:
- PFO is a normal variant present in about 25-30% of adults
- It represents persistence of a normal fetal communication between the atria
- The overwhelming majority of people with PFO never experience any complications
- No specific treatment or lifestyle modifications are needed
- They should seek immediate medical attention if they develop stroke symptoms (as should anyone, regardless of PFO status)
Important Caveats
Special Populations Requiring Consideration
While routine incidental PFO requires no intervention, certain high-risk scenarios may warrant discussion with cardiology:
- Thrombophilia patients: One recent study suggested potential benefit of closure in thrombophilic patients even without prior events 3, but this is based on limited retrospective data and is NOT standard practice
- Pregnant patients with additional risk factors: Pregnancy itself increases stroke risk, and combined with PFO may warrant specialized consultation 4
- Professional divers: May need individualized risk assessment due to decompression illness risk
However, even in these populations, routine prophylactic closure is not recommended based on current evidence.
What NOT to Do
Common pitfalls to avoid:
- Do not order transesophageal echocardiography to "better characterize" an incidental PFO found on routine imaging
- Do not refer to cardiology for closure consideration in asymptomatic patients
- Do not start antiplatelet or anticoagulation therapy
- Do not counsel patients that they are at increased stroke risk requiring intervention
The Evidence Base
The 2018 BMJ guidelines are explicit that recommendations for PFO closure "apply to patients under 60 years old with patent foramen ovale (PFO) who have had a cryptogenic ischaemic stroke" 1. The American Academy of Neurology states that "available data do not support a benefit for PFO closure" in patients without cryptogenic stroke 1.
The size of the PFO (small vs. large) does not change management in asymptomatic patients—closure is not indicated regardless of shunt size when there is no history of embolic events.