From the Guidelines
Transesophageal echocardiography (TEE) is the preferred method for patent foramen ovale (PFO) assessment due to its higher sensitivity and specificity compared to transcranial Doppler (TCD). TEE provides direct visualization of the atrial septum and can characterize PFO anatomy, size, and associated features like atrial septal aneurysm, as noted in the 2018 BMJ study 1. The sensitivity of TEE for PFO detection is excellent, ranging from 89-100%, and its specificity is also high, ranging from 91-100%.
Some key points to consider when choosing between TCD and TEE for PFO assessment include:
- TEE offers excellent sensitivity and specificity for PFO detection, making it the gold standard for diagnosis 1
- TCD is a good initial screening tool with high sensitivity but lower specificity, and it cannot directly visualize the defect or distinguish between cardiac and pulmonary shunts
- The recommended approach is often to use TCD as an initial screening test, followed by TEE for positive or equivocal results, especially when considering PFO closure
- A Valsalva maneuver should be performed during bubble studies to transiently increase right atrial pressure and reveal shunts that might otherwise remain closed, as recommended in the 2018 BMJ study 1
In terms of the evidence, the 2018 BMJ study 1 provides the most recent and highest quality guidance on the use of TEE for PFO assessment. The study notes that TEE is recommended for younger adults with unexplained cerebrovascular events, and that it offers excellent sensitivity and specificity for PFO detection. Other studies, such as the 2015 Circulation study 1 and the 2009 Circulation study 1, also support the use of TEE for PFO assessment, but the 2018 BMJ study 1 provides the most up-to-date and comprehensive guidance.
Overall, while both TCD and TEE are effective for PFO assessment, TEE is the preferred method due to its higher sensitivity and specificity, and its ability to provide direct visualization of the atrial septum and characterize PFO anatomy.
From the Research
Comparison of Transcranial Doppler and TEE for PFO Assessment
- Transcranial Doppler (TCD) and Transesophageal Echocardiography (TEE) are two diagnostic tools used to assess Patent Foramen Ovale (PFO) 2, 3, 4, 5.
- TEE is considered the gold standard for anatomic assessment of PFO, but TCD has been proposed as a minimally invasive alternative for detecting right-to-left shunt 2, 3.
- Studies have shown that TCD has a high sensitivity and specificity for detecting PFO, with some studies suggesting that it may be more sensitive than TEE in certain cases 4, 5.
- The combination of TCD and TEE may provide a more comprehensive assessment of PFO, with TCD detecting right-to-left shunt and TEE providing anatomic details 3, 5.
Diagnostic Accuracy of TCD and TEE
- A study of 1358 patients found that TCD and contrast-enhanced transthoracic echocardiography (CE-TTE) had a high agreement rate for detecting PFO, with a Cohen kappa of 78.6% 2.
- Another study of 45 patients found that TEE detected PFO in 24 cases, while TCD detected PFO in 22 cases, with a sensitivity of 92.3% for TEE and 84.6% for TCD 3.
- A study of 134 patients found that TTE and TCD had higher sensitivity than TEE for detecting PFO, with a sensitivity of 100% for TTE and 97% for TCD 4.
- A study of 100 patients found that TCD had a sensitivity of 96.8% and specificity of 78.4% for detecting PFO, with a general concordance of up to 90% between TCD and TEE 5.
Clinical Relevance of TCD and TEE
- TCD has been shown to be useful in detecting right-to-left shunt at rest, with a higher sensitivity than TEE in some cases 5.
- TEE has a major role in the diagnostic evaluation of PFO, as well as in the post-procedural assessment after transcatheter closure 6.
- The combination of TCD and TEE may aid in the prevention of paradoxical embolism in individuals with and without cerebrovascular diseases 5.