A 47-year-old asymptomatic female has a patent foramen ovale (PFO) identified on cardiac CT angiography but a negative transthoracic echocardiogram; what is the next step in management?

Next Step: Transesophageal Echocardiography with Bubble Study

For this 47-year-old asymptomatic woman with discordant PFO findings (positive on cardiac CT but negative on transthoracic echo), the next step is to perform transesophageal echocardiography (TEE) with agitated saline contrast and Valsalva maneuver to definitively confirm or exclude the PFO. 1

Why TEE is the Definitive Next Step

TEE is the gold standard for PFO diagnosis and should be performed when transthoracic echocardiography is non-diagnostic or inconclusive in suspected congenital heart disease. 1, 2 The European Heart Association specifically recommends TEE for "non-diagnostic transthoracic echocardiography in suspected CHD" as a Class I indication. 1

Key Technical Considerations for the TEE Study

• The study must include multiple agitated saline injections during Valsalva maneuver or cough to transiently increase right atrial pressure and enhance sensitivity for detecting right-to-left shunting through the PFO. 2, 3

• PFO is definitively diagnosed by demonstrating right-to-left transit of contrast microbubbles within 3-4 cardiac cycles of right atrial opacification. 1, 3

• TEE has significantly higher sensitivity than transthoracic echo for PFO detection (24.3% detection rate with TEE vs 14.9% with transthoracic echo in population studies), explaining why the initial TTE was negative. 1

Critical Anatomical Features to Document on TEE

If a PFO is confirmed, the following high-risk features must be documented as they influence future management decisions:

• Largest defect diameter and shunt size (small, moderate, or large based on number of microbubbles crossing). 1, 2

• Presence of atrial septal aneurysm (defined as >10mm excursion of interatrial septum from centerline), which occurs in 2.5% of the population and significantly increases embolic risk when present with PFO. 1, 3, 4

• Tissue rim measurements around the defect (superior vena cava, aortic, coronary sinus, inferior vena cava, and posterior segments), as rim width <5mm may preclude device closure if ever needed. 1

• Exclusion of other cardiac sources of embolism including atrial thrombi, valve vegetations, cardiac tumors, or true atrial septal defects. 2

Management After TEE Confirmation

If PFO is Confirmed and Patient Remains Asymptomatic

No intervention is required for an isolated PFO in an asymptomatic patient without history of stroke or systemic embolism. 4, 5 Several key points support conservative management:

• Asymptomatic patients with PFO do not have an increased risk of first stroke compared to the general population. 5 PFO is present in approximately 25% of all adults and is a normal variant of fetal circulation. 1, 3, 6, 5

• Routine surveillance echocardiography of asymptomatic patients with PFO is rated "Rarely Appropriate" by the American College of Cardiology. 2

• No antiplatelet or anticoagulation therapy is indicated in asymptomatic patients with incidentally detected PFO, as there is no evidence of benefit and potential for harm. 4

• PFO closure is not indicated in the absence of documented paradoxical embolism or cryptogenic stroke. 4

If PFO is Not Confirmed on TEE

If TEE with proper technique (including Valsalva maneuver) fails to demonstrate a PFO, then the cardiac CT finding was likely a false positive or anatomical variant, and no further cardiac workup is needed. 1 The patient can be reassured that no clinically significant interatrial communication exists.

Common Pitfalls to Avoid

• Do not proceed directly to PFO closure or anticoagulation based solely on the cardiac CT finding without TEE confirmation, as this would expose the patient to unnecessary procedural risks or bleeding complications. 2, 4

• Do not order transcranial Doppler as the next step when TEE is readily available and provides superior anatomical detail needed for complete assessment. 2

• Ensure the TEE includes proper provocative maneuvers (Valsalva or cough during contrast injection), as failure to perform these maneuvers is the most common reason for false-negative studies. 2, 3

• Do not confuse PFO with ostium secundum atrial septal defect – PFO is confined to the fossa ovalis without septal deficiency, while ASD represents true deficiency of septum primum or secundum requiring different management. 3, 4