Association Between Left Atrial Appendage Morphology Evaluated by Trans-Esophageal Echocardiography and Ischemic Cerebral Stroke in Patients With Atrial Fibrillation

Abstract

SummaryThe left atrial appendage (LAA) represents one of the major sources of cardiac thrombi responsible for embolic stroke in patients with atrial fibrillation (AF). The aim of the present study was to evaluate LAA structure and functions by transesophageal echocardiography (TEE) in patients with AF to investigate the possible association between the different LAA morphologies and the patients' history of ischemic cerebral stroke. We included 50 patients with non-valvular AF (29 chronic, 21 paroxysmal), 24 patients (13 men) without stroke; and 26 patients (9 men) with a history of ischemic stroke. All patients underwent TEE evaluation of LAA morphology and functions. Compared to patients without stroke, patients with ischemic stroke had significantly higher CHADS2 scores (4.19 ± 0.89 versus 1.67 ± 1.13; P < 0.001) and C-reactive protein levels (8.3 ± 1.6 versus 7.6 ± 0.83 mg/L; P = 0.023), and lower peak filling (21.7 ± 11.3 versus 31.2 ± 9.5 cm/second; P = 0.033) and emptying (22.2 ± 9.7 versus 33.4 ± 13.4 cm/second, P = 0.030) velocities. Triangular LAA morphology had a higher prevalence in patients with stroke (36% versus 12% in non-stroke group); and in half of them an LAA thrombus was present. LAA thrombi were detected in 9 patients (18%) with stroke and in 5 patients (10%) Approximately 33% of arrhythmiarelated hospitalizations are for AF, which is also associated with a 5-fold increase in the risk of stroke and 2-fold increase in the risk of all cause mortality. 1) AF causes 15-20% of ischemic strokes, and the annual risk of stroke in patients with nonvalvular AF is as high as 5%.2)The left atrial appendage (LAA) has been described as a long, narrow, tubular, wavy, hooked structure with different lobes and a narrow junction and crenellated lumen. 3,4) As the LAA represents one of the major sources of cardiac thrombus formation responsible for stroke in patients with AF, 5,6) the imaging of the different structures and lobes is of utmost importance to diagnose the presence of thrombus, especially in patients with non-valvular AF. 7,8) Multidetector computed tomography 9) and contrast-enhanced magnetic resonance imaging 10) are able to image the LAA; however, it was concluded that magnetic resonance imaging lacks diagnostic accuracy for the detection of LAA thrombi.10) Transesophageal echocardiography (TEE) is the gold standard to detect LAA thrombus, 11) but false positive results still occur.12) In this study, we evaluated the LAA structure and functions by TEE in patients with non-valvular AF (both chronic and paroxysmal types) to study the possible association between the different LAA morphologies and functional changes with the patients' history of ischemic cerebral stroke. MethodsStudy design and participants: This study was conducted on 50 patients with non-valvular AF; including both chronic (29 patients, 58%) and paroxysmal (21 patients, 42%) cases. We included patients with documented paroxysmal AF because large, prospective studies have shown that the risk for thromboembolism does not differ ...

Association between left atrial appendage fibrosis and thrombus formation: A histological approach

“…Previous echocardiographic studies compared morphologic parameters of LAA and LAAT, and suggested that left atrium/LAA enlargements contributed to LAAT formation. [14][15][16] Consistent with previous reports, we found that left atrial volume, LAA orifice dimension, LAA depth, and LAA flow velocity were associated with LAAT. However, histological evidence has been absent regarding this issue.…”

Predictive value of left atrial appendage lobes on left atrial thrombus or spontaneous echo contrast in patients with non-valvular atrial fibrillation

“…One possible mechanism behind may be that the incidence of thrombi formation in LAA with different anatomical characteristics, i.e., LAA morphology and number of LAA lobes, varied. Now it is recognized that there were four LAA macroscopic morphologies, including cactus LAA, chicken wing LAA, windsock LAA and cauliflower LAA [ 5 , 16 – 21 ]. Several recent studies have demonstrated that different LAA morphologies obtained by Cardiac CT or MRI are closely correlated with LASEC, transient ischaemic attacks (TIA) and strokes in patients with AF [ 16 – 21 ].…”

“…Now it is recognized that there were four LAA macroscopic morphologies, including cactus LAA, chicken wing LAA, windsock LAA and cauliflower LAA [ 5 , 16 – 21 ]. Several recent studies have demonstrated that different LAA morphologies obtained by Cardiac CT or MRI are closely correlated with LASEC, transient ischaemic attacks (TIA) and strokes in patients with AF [ 16 – 21 ]. However, the relationship between LAA lobes and markers of thromboembolic risk (decreased LAA flow velocity, LASEC, LA thrombus) has not been fully characterized in patients with NVAF.…”

Left Atrial Appendage Morphology as a Determinant for Stroke Risk Assessment in Atrial Fibrillation Patients: Systematic Review and Meta-Analysis

“…On the other hand, several morphological and functional abnormalities including LAA orifice area, LAA depth, LAA volume and LAA flow velocity have been studied in several observational studies. [19][20][21][22][23][24] It has been shown that the increase in LAA orifice area, depth and volume and decrease in LAA velocity are strongly associated with increased stroke risk in AF. [19][20][21][22][23][24] These changes are attributable to blood pooling and stasis triggered by AF itself.…”

“…[19][20][21][22][23][24] It has been shown that the increase in LAA orifice area, depth and volume and decrease in LAA velocity are strongly associated with increased stroke risk in AF. [19][20][21][22][23][24] These changes are attributable to blood pooling and stasis triggered by AF itself. Therefore, a systematic review and meta-analysis of all studies that address these parameters should be done in order to demonstrate the final association between these variables and the risk of embolic stroke and try to find a cut-off values that could help in assessing the risk of thromboembolism in AF patients.…”