When should a small patent foramen ovale (PFO) only visible with Valsalva maneuver on bubble study be closed?

When to Close a Small PFO Only Visible with Valsalva on Bubble Study

A small PFO visible only with Valsalva maneuver should be closed if the patient is aged 18-60 years with a confirmed cryptogenic embolic stroke (non-lacunar, imaging-confirmed) after thorough neurological evaluation excludes other causes, and the patient does not require long-term anticoagulation. 1, 2

Key Criteria That Must ALL Be Met for Closure

The decision to close a PFO—even a small one only visible with Valsalva—depends on meeting specific criteria established by major stroke guidelines:

Age Requirement

• Patient must be 18-60 years old 1, 2
• PFO closure is NOT recommended for patients >60 years, regardless of shunt size 1

Stroke Characteristics Required

• Confirmed embolic ischemic stroke or TIA with positive neuroimaging or cortical symptoms 1
• Must be NON-LACUNAR (small deep infarcts are contraindications to closure) 2
• Stroke must be cryptogenic after comprehensive workup 1

Critical Exclusion Criteria

Before attributing stroke to PFO, you must exclude:

• Atrial fibrillation 2
• Left-sided cardiac disease 2
• Severe atherosclerosis of thoracic aorta 2
• Any indication for long-term anticoagulation 1, 2

Neurological Evaluation Requirement

• Must be evaluated by neurologist or clinician with stroke expertise who determines the PFO is the most likely cause after thorough etiological evaluation 1

Understanding Shunt Size in Context

While your question focuses on a "small" PFO only visible with Valsalva, the evidence shows nuanced considerations:

The REDUCE Trial Evidence

• 81% of patients had moderate (6-25 microbubbles) or large (>25 microbubbles) shunts 1
• The trial included PFOs with right-to-left shunt either spontaneous OR during Valsalva maneuver 1
• Stroke reduction was significant: 1.4% vs 5.4% (NNT=28 to prevent 1 stroke in 2 years) 1

The CLOSE Trial Criteria

• Required EITHER atrial septal aneurysm (excursion >10mm) OR large interatrial shunt (>30 microbubbles) 1
• This trial showed the most dramatic benefit: 0% vs 6.0% stroke rate (NNT=20 over 5 years) 1

The RESPECT Trial Subgroup Analysis

• Benefit appeared driven by those with atrial septal aneurysm or "substantial" shunt size (grade 3) 1
• This suggests small shunts without high-risk features may have less benefit 1

High-Risk PFO Features That Strengthen the Case for Closure

Even with a small shunt, presence of these features increases likelihood of benefit:

• Atrial septal aneurysm (OR 15.59 for stroke risk in patients ≤55 years) 2
• Confirmed venous thrombosis or pulmonary embolism supporting paradoxical embolism diagnosis 2

When NOT to Close a Small PFO

Do NOT close if:

• Patient >60 years old 1
• Lacunar stroke pattern 2
• Low-risk PFO (no atrial septal aneurysm, small shunt) in absence of cryptogenic stroke 2
• PFO is likely incidental rather than causal 1
• Patient requires long-term anticoagulation for another indication 1, 2
• For primary stroke prevention (no prior stroke/TIA) 1
• For migraine with aura (insufficient evidence) 2
• For peripheral embolism (MI, renal infarction, limb ischemia) without cerebral involvement 2

Procedural Risk Considerations

Patients must understand and accept upfront procedural risks:

• Atrial fibrillation: 4.6-6.6% (mostly transient) 1
• Serious device-related adverse events: 1.4-5.9% 1
• Overall procedural success rate: 98.9% 3
• Late complications include pericardial effusion, device erosion, and thrombus formation (device-specific) 3

Clinical Algorithm for Your Specific Question

For a small PFO only visible with Valsalva:

1. Has the patient had a cryptogenic stroke/TIA?

   • If NO → Do not close 1
   • If YES → Proceed to step 2

2. Is patient 18-60 years old?

   • If NO → Do not close 1
   • If YES → Proceed to step 3

3. Has neurologist confirmed non-lacunar embolic stroke after excluding AF, left-sided cardiac disease, and severe aortic atherosclerosis?

   • If NO → Do not close 1, 2
   • If YES → Proceed to step 4

4. Does patient require long-term anticoagulation?

   • If YES → Do not close (unclear benefit) 1, 2
   • If NO → Proceed to step 5

5. Are there high-risk features (atrial septal aneurysm or larger shunt)?

   • If YES → Strongly recommend closure 1, 2
   • If NO (truly small shunt only with Valsalva) → Consider closure with shared decision-making, acknowledging that trial evidence was strongest for moderate-to-large shunts, but REDUCE trial did include Valsalva-only shunts 1

Important Caveats

• Patient counseling and shared decision-making are critical 1
• The benefit is prophylactic—patients will not experience symptomatic improvement except in rare cases of hypoxemia 4
• Post-closure antiplatelet therapy is required long-term 5
• The evidence level remains Class IIb (insufficient data for definitive recommendations) per American College of Cardiology, though Canadian guidelines upgraded to Level A for carefully-selected patients 1, 2