When is treatment indicated for a patent foramen ovale (PFO)?

When Does a PFO Require Treatment?

PFO closure is indicated in carefully selected patients aged 18-60 years who have suffered a cryptogenic stroke with high-risk PFO features (large shunt or atrial septal aneurysm), after excluding other stroke causes including atrial fibrillation, left-sided cardiac disease, and severe aortic atherosclerosis. 1

Primary Indication: Cryptogenic Stroke in Young Patients

The strongest evidence supports PFO closure in a specific clinical scenario:

• Patient age 18-60 years with confirmed cryptogenic embolic stroke after thorough neurological evaluation excludes other causes 1
• High-risk PFO features must be present: atrial septal aneurysm (which increases stroke risk with OR 15.59 in patients ≤55 years) or moderate-to-large shunt (6-25 or >25 microbubbles on contrast echocardiography) 1
• No indication for long-term anticoagulation for other reasons 1

The benefit is real but modest: pooled trial data show stroke recurrence of 3.6% with closure versus 5.8% with medical therapy alone (OR 0.62), with NNT of 28 to prevent one stroke over 2 years in the REDUCE trial 1, 2

Critical Exclusion Criteria Before Attributing Stroke to PFO

Before considering PFO as the stroke mechanism, you must exclude:

• Atrial fibrillation through prolonged cardiac monitoring (not just initial ECG) 1
• Left-sided cardiac disease including left atrial/ventricular thrombus, severe LV dysfunction 1
• Severe atherosclerosis of thoracic aorta on imaging 1
• Small deep infarcts (lacunar strokes) which suggest small vessel disease, not embolic mechanism 1

When PFO Closure is NOT Indicated

Absolute Contraindications to Closure:

• Patients requiring long-term anticoagulation for any reason (atrial fibrillation, mechanical valve, venous thromboembolism) 1
• Low-risk PFO (no atrial septal aneurysm, small shunt) even with cryptogenic stroke 1
• Age >60 years where benefit is uncertain and complication risk may outweigh benefit 1
• Lacunar stroke pattern on imaging 1

Insufficient Evidence (Do Not Close):

• Primary prevention in asymptomatic patients with incidentally discovered PFO 3
• Migraine with aura despite theoretical appeal—current evidence does not support closure 1, 4
• Peripheral paradoxical embolism (MI, renal infarction, limb ischemia) lacks evidence-based support for causal connection 1

Special Circumstances Requiring Case-by-Case Assessment

Consider Closure Only in These Rare Scenarios:

• Recurrent decompression sickness in individuals who must continue high-risk activities (high-volume divers, compressed-air tunnel workers, high-altitude aviators, astronauts) after multiple recurrences 1
• Right-sided cardiac disease with elevated right atrial pressures causing significant right-to-left shunting and documented hypoxemia—decision must be highly individualized 1

Procedural Risks to Discuss with Patients

Patients must understand closure carries real risks:

• Atrial fibrillation: 4.6-6.6% incidence post-procedure 1
• Serious device-related adverse events: 1.4-5.9% including pericardial effusion, device erosion, thrombus formation 1
• Procedural success rate: 98.9%, but late complications can occur 1

Medical Therapy When Closure is Denied or Contraindicated

If PFO closure is not performed in a patient with PFO-attributed stroke/TIA:

• Single antiplatelet therapy is the primary recommendation unless specific indications for anticoagulation exist 5
• Anticoagulation is chosen when evidence of venous thromboembolism is present, documented hypercoagulable state exists, or recurrent events occur on antiplatelet therapy 5
• NOT dual antiplatelet therapy—guidelines reference single agent only 5

Common Pitfalls to Avoid

• Do not close PFO in patients with isolated PFO and no prior embolic event—25% of adults have PFO as an incidental anatomical variant requiring no intervention 3, 6
• Do not attribute every cryptogenic stroke to PFO—the recurrence risk is actually low, and many cryptogenic strokes have other unidentified mechanisms 6
• Do not close small PFOs visible only with Valsalva in patients >60 years—age is a critical selection criterion 1
• Do not skip the hypercoagulable workup—confirming venous thrombosis or pulmonary embolism when possible strengthens the paradoxical embolism diagnosis 1