Transthoracic Doppler echocardiography for the assessment of left atrial appendage size and blood flow velocity. A multicentre study

OBJECTIVE: The aim of this study was to evaluate the reliability of transthoracic Doppler echocardiography (TTE) in the assessment of left atrial appendage (LAA) size and function. METHODS: We considered 86 consecutive patients [56 male, 30 female; mean age 64 +/- 13 years, sinus rhythm 36 patients (42%); atrial flutter/fibrillation 50 patients (58%)] referred for transoesophageal echocardiography (TEE) and TTE. Maximum LAA transverse diameters and LAA peak flow velocities were calculated by two-dimensional and pulsed-wave Doppler analysis at TEE and TTE. RESULTS: LAA systolic transverse diameters were detectable in 78 patients (91%) by TTE and showed a significant correlation with TEE (r = 0.77, P < 0.0001). LAA peak flow velocities were measurable by TTE in 72 patients (84%) and were comparable with TEE (50.4 +/- 23 vs 47.3 +/- 23.2 cm/s, r = 0.67, P < 0.0001). A peak blood flow velocity of <25 cm/s at TTE was the best indicator of very low (<20 cm/s) LAA flow velocity as detected by TEE (sensitivity 93%, specificity 87%, area under the curve 0.94, P < 0.0001). Conversely, a peak blood flow velocity of >56 cm/s at TTE indicated a very high (> 40 cm/s) LAA flow velocity as detected by TEE (sensitivity 50%, specificity 96%, area under the curve 0.87; P < 0.0001). CONCLUSIONS: Reliable LAA size and blood flow velocities can be obtained by TTE in consecutive, unselected patients. TTE identifies patients with low and high blood flow velocities in the LAA, providing helpful information for the definition of individual embolic risk.