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Validation of transesophageal echocardiography to determine physiologic coronary flow
F A Chaudhry1, J F Ren, K Ramani
1Columbia University, College of Physicians and Surgeons, Division of Cardiology, St. Luke's-Roosevelt Hospital Center, 1111 Amsterdam Avenue, New York, NY 10025, USA. fchaudhry@slrhc.org
Insights
Doppler transesophageal echocardiography (TEE) shows promise for measuring coronary blood flow (CBF), though it tends to overestimate values. This method requires further validation for accurate clinical assessment of CBF.
Area of Science:
- Cardiovascular Physiology
- Diagnostic Imaging Techniques
Background:
- Doppler transesophageal echocardiography (TEE) is suggested for assessing coronary blood flow (CBF).
- Previous studies indicate TEE's potential for detecting alterations in CBF due to stenoses.
- Validation of CBF assessment by Doppler TEE is currently lacking.
Purpose of the Study:
- To validate the accuracy of Doppler TEE for estimating coronary blood flow (CBF).
- To compare CBF measurements obtained by Doppler TEE with established methods.
Main Methods:
- Seven mongrel dogs were used for the study.
- Simultaneous CBF measurements were taken using Doppler TEE and epicardial electromagnetic flow (EMF) or Doppler flow (EDF) probes.
- Measurements were recorded at baseline and during induced reactive hyperemia following coronary occlusion.
Main Results:
- Doppler TEE provided consistent flow waveforms across 34 measurements.
- Doppler TEE generally overestimated CBF compared to EMF/EDF (TEE Flow = 1.1 * EMF/EDF flow + 26.3).
- Mean TEE flow was 85 ml/min versus 53 ml/min for EMF/EDF.
Conclusions:
- Doppler TEE is a promising technique for measuring coronary blood flow (CBF) within the physiologic range.
- Further validation is needed to refine the accuracy of Doppler TEE for clinical CBF assessment.
- The tendency for overestimation by Doppler TEE requires consideration in interpretation.
Unlabelled:
Human studies have suggested that Doppler transesophageal echocardiography (TEE) can determine normal physiologic coronary blood flow (CBF) and alterations in CBF due to proximal flow-limiting stenoses. However, assessment of CBF by Doppler TEE has not been validated. To determine if true estimation of CBF could be obtained with Doppler TEE, seven mongrel dogs (weight range 28 kg-36 kg) were evaluated. Simultaneous CBF determinations by Doppler TEE and epicardial electromagnetic flow (EMF) and/or epicardial Doppler flow (EDF) probes were compared. Measurements were obtained at baseline and following varying degrees of proximal coronary occlusion, which produced reactive hyperemia.
Results:
Consistent Doppler flow waveforms were obtainable by Doppler TEE in 34 different measurements during perturbations: Mean for TEE Flow (ml/min) = 85, EMF or EDF Flow (ml/min) = 53; Standard Deviation for TEE Flow (ml/min) = 45, EMF or EDF Flow (ml/min) = 38; Minimum for TEE Flow (ml/min) = 42, EMF or EDF Flow (ml/min) = 11; and Maximum for TEE Flow (ml/min) = 174, EMF or EDF Flow (ml/min) = 130. TEE Flow (ml/min) = 1.1 EMF/EDF flow + 26.3. There was a general trend towards overestimation of CBF by Doppler TEE. This study demonstrates that Doppler TEE is a promising method for obtaining measurements of CBF over the physiologic range.