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Need for performance protocols in TEE and TCD for detection of right to left shunts
Jason Chang1, Carol Darbonne, Denise A Drumm
1Neurology Department, Barrow Neurological Institute, Phoenix, AZ.
Insights
Transesophageal echocardiography (TEE) and transcranial Doppler (TCD) for detecting right-to-left shunts are operator-dependent. TCD demonstrated higher sensitivity than TEE, suggesting a need for standardized TEE protocols to improve accuracy.
Area of Science:
- Neurology
- Cardiology
- Medical Imaging
Background:
- Transesophageal echocardiography (TEE) is the standard for detecting right-to-left shunts.
- Transcranial Doppler (TCD) has shown higher sensitivity in preliminary observations.
Purpose of the Study:
- To investigate the discrepancy in sensitivity between TCD and TEE for right-to-left shunt detection.
- To identify factors contributing to the observed differences in diagnostic performance.
Main Methods:
- Retrospective evaluation of 118 patients with cryptogenic stroke and transient ischemic attacks.
- Comparison of TCD and TEE results, with TCD following a published protocol and TEE lacking a standardized approach.
- Statistical analysis using chi-squared tests, Fisher exact tests, and ANOVA.
Main Results:
- Overall agreement between TCD and TEE was 76 out of 118 patients.
- TCD sensitivity was 93.8% compared to 53.1% for TEE.
- Significant interoperator variability was noted for TEE, with sensitivities ranging from 46.7% to 75.7%.
Conclusions:
- Both TEE and TCD are operator-dependent, leading to potential false negatives.
- Lack of standardized protocols for TEE microbubble studies contributes to lower yield and variability.
- Establishing consensus performance protocols and certification criteria for both modalities is crucial for improving shunt detection accuracy.
Background And Purpose:
Although transesophageal echocardiography (TEE) is the gold standard for right to left shunt detection, we observed that transcranial Doppler (TCD) was more sensitive and sought an explanation.
Methods:
We retrospectively evaluated results of TCD and TEE in 118 patients with cryptogenic stroke and transient ischemic attacks. TCDs were done as per modification of a published performance protocol and interpreted by a neurologist and radiologist. TEEs were performed and interpreted by five cardiologists without standardized protocol. Statistical methodology included χ(2) tests, Fisher exact tests, and ANOVA.
Results:
Overall agreement between TCD and TEE was found for 76 of 118 patients. Sensitivities of TCD and TEE were 93.8% and 53.1%. Sensitivities for TCD interpreters were 61.1% and 64.1%. Sensitivities for TEE operators varied from 46.7% to 75.7%. We were unable to find a performance protocol for TEE microbubble studies in either published literature or certification organizations.
Conclusions:
TEEs and TCDs are operator dependent and thus subject to false negatives. The lower yield and interoperator variability in TEE results appear to reflect the lack of performance protocols and engender concern about false negatives in community use. Consensus performance protocols and certification criteria for both modalities should have an impact on accuracy of shunt detection.
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