Why is a Transesophageal Echocardiogram (TEE) performed after a stroke?

Transesophageal Echocardiography (TEE) After Stroke: Rationale and Clinical Utility

TEE is performed after stroke primarily to identify potential cardiac sources of embolism that may not be detected by transthoracic echocardiography, particularly in cases of cryptogenic stroke where the cause remains undetermined after initial evaluation. 1

Diagnostic Value of TEE in Stroke Evaluation

TEE offers significant advantages over other cardiac imaging modalities in stroke patients:

• Superior detection of embolic sources: TEE is the most sensitive and specific technique for detecting cardiac sources of embolism 1
• Visualization capabilities: By placing high-frequency ultrasound transducers close to the heart, TEE provides high-quality images of cardiac structures that may be difficult to visualize with transthoracic echocardiography (TTE) 1
• Detection rate: TEE can identify potential cardiac sources of embolism in approximately 40% of patients with normal TTE findings, regardless of age 2

Specific Cardiac Abnormalities Detected by TEE

TEE is particularly valuable for identifying:

1. Left atrial/left atrial appendage (LA/LAA) thrombi - found in 5-15% of stroke patients before cardioversion 1
2. Patent foramen ovale (PFO) - a potential pathway for paradoxical embolism 1, 3
3. Aortic atheroma ≥4mm - associated with increased stroke risk 2, 3
4. Spontaneous echo contrast - indicator of blood stasis and thromboembolism risk 1
5. Reduced LAA flow velocity - marker for potential thrombus formation 1
6. Valvular vegetations - indicating infective endocarditis 3
7. Intracardiac masses - tumors or other abnormal structures 4

Clinical Impact on Management

TEE findings frequently lead to significant changes in clinical management:

• Anticoagulation initiation: TEE findings may lead to anticoagulation in 8.7-20% of patients with previously unidentified high-risk cardiac sources 1, 3
• PFO closure: Identification of PFO may lead to consideration of closure device placement in appropriate candidates 3, 5
• Antibiotic therapy: Detection of endocarditis requires prompt antibiotic treatment 3
• Overall management impact: TEE findings change clinical management in approximately 16.7% of patients with suspected cardioembolic stroke 3

When to Perform TEE After Stroke

According to the 2021 AHA/ASA guidelines 1:

• Cryptogenic stroke: TEE might be reasonable to identify possible cardioaortic sources or transcardiac pathways for cerebral embolism (Class 2b, Level of Evidence C-LD)
• PFO evaluation: In patients where PFO closure would be contemplated, transcranial Doppler with embolus detection might be reasonable to screen for right-to-left shunt, with TEE often used for confirmation (Class 2b, Level of Evidence C-LD)

Limitations and Considerations

• Invasiveness: TEE is semi-invasive and associated with small risks (cardiac, pulmonary, and bleeding complications in 0.18% of cases) 4
• Patient selection: The highest yield is in patients with clinical evidence of cardiac disease (up to 19%) versus those without (less than 2%) 4
• Alternative imaging: Cardiac CT and cardiac MRI are emerging alternatives but have not fully replaced TEE as the gold standard 1, 6

Practical Approach to TEE After Stroke

1. Consider TEE in patients with:

   • Cryptogenic stroke after initial evaluation
   • Clinical evidence of cardiac disease
   • Age <55 years with no other identified stroke etiology
   • Suspected paradoxical embolism

2. TEE may be deferred when:

   • Clear non-cardiac cause of stroke is identified
   • Patient already has an established indication for anticoagulation
   • Patient has contraindications to anticoagulation regardless of findings

TEE remains a valuable diagnostic tool in the evaluation of stroke patients, particularly when the initial workup fails to identify a clear etiology, with the potential to significantly impact clinical management and reduce recurrent stroke risk.