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Left atrial appendage Doppler flow patterns: implications on thrombus formation
M A García-Fernández1, E G Torrecilla, D San Román
1Cardiology Department, Hospital General Gregorio Marañón, Madrid, Spain.
Insights
Transesophageal echocardiography identified three distinct left atrial appendage (LAA) flow patterns. Atrial fibrillation is linked to larger LAA size and increased thrombus risk, particularly with type III flow.
Area of Science:
- Cardiology
- Medical Imaging
Background:
- The clinical significance of left atrial appendage (LAA) flow dynamics remains incompletely understood.
- Transesophageal echocardiography (TEE) is crucial for evaluating cardiac structures and function.
Purpose of the Study:
- To analyze the characteristics and clinical implications of LAA flow patterns using TEE color Doppler.
- To correlate LAA flow patterns with echocardiographic variables and cardiac rhythm.
Main Methods:
- A TEE color Doppler study was performed on 39 consecutive patients.
- LAA pulsed Doppler flow patterns were assessed and categorized.
- Echocardiographic variables, cardiac rhythm, LAA size, spontaneous contrast, and thrombus presence were evaluated.
Main Results:
- Three distinct LAA flow patterns were identified: Type I (biphasic, sinus rhythm, no thrombus/contrast), Type II (sawtooth, atrial fibrillation, dilated LAA, no thrombus/contrast), and Type III (no waves, atrial fibrillation, very dilated LAA, spontaneous contrast, high thrombus incidence).
- Type I flow showed mean peak velocities of 28 cm/sec (filling) and 31 cm/sec (emptying).
- Type II flow (atrial fibrillation) had a mean peak velocity of 49 cm/sec in a LAA area of 421 mm².
- Type III flow (atrial fibrillation) was associated with significantly larger LAA area (619 mm²) and spontaneous contrast, with 6/7 patients having thrombus.
Conclusions:
- TEE can differentiate three LAA flow patterns with distinct clinical implications.
- Atrial fibrillation is associated with altered LAA flow (Types II and III) and larger LAA dimensions.
- Type III LAA flow pattern in AF patients indicates a significantly higher risk of LAA thrombus formation.
Abstract:
The characteristics and clinical implications of left atrial appendage (LAA) flow have not been clearly analyzed. Thirty-nine consecutive patients underwent a transesophageal echocardiographic (TEE) color Doppler study to correlate the LAA pulsed Doppler flow pattern with echocardiographic variables and the cardiac rhythm of each patient. Three different LAA flow patterns were identified. Type I flow, characterized by a biphasic pattern (waves of filling and emptying), was found in 17 patients, all in sinus rhythm; it was not associated with LAA spontaneous contrast or thrombus. Mean peak velocities of the filling and emptying waves were, respectively: 28 +/- 12 cm/sec and 31 +/- 9 cm/sec. Type II sawtooth active flow (eight patients) (mean peak velocity: 49 +/- 12 cm/sec) was only detected in atrial fibrillation (AF) and dilated LAA (LAA area: 421 +/- 40 mm2) but without thrombus or significant LAA spontaneous echocardiographic contrast. Type III flow pattern was noted in 14 patients with AF and a very dilated LAA (LAA area: 619 +/- 96 mm2). This flow pattern was characterized by the absence of identifiable flow waves and was associated with the presence of LAA spontaneous contrast; the majority (six of seven) had evidence of thrombus. We concluded that the LAA is a dynamic structure in which TEE study identified three flow patterns with different implications. AF is associated with two LAA flow types (II and III) with a larger LAA size as well as a higher incidence of LAA clots in type III flow.