Validation of transesophageal echocardiography to determine physiologic coronary flow

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: TEE Flow EMF or EDF (ml/min) Flow (ml/min) Mean 85 53 Standard Deviation 45 38 Minimum 42 11 Maximum 174 130 TEE Flow (ml/min) = 1.1 EMF/EDF fiow + 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.