Comparison of two and three dimensional transthoracic versus transesophageal echocardiography in evaluation of anatomy and pathology of left atrial apendage

Transesophageal echocardiography and computerized tomography angiography mismatch in left atrial appendage thrombus evaluation

BACKGROUND

Transesophageal echocardiography (TEE) is the gold standard test for the diagnosis of left atrial appendage (LAA) thrombus. Nonetheless, computerized tomography angiography (CTA) is readily used to exclude LAA thrombus before pulmonary vein isolation (PVI) and LAA closure procedures. We aimed to assess the comparability of LAA thrombus diagnosis using chest CTA scans in patients with atrial fibrillation who underwent TEE.

METHODS

Retrospective collection of consecutive patients with atrial fibrillation who underwent TEE and chest CTA within 30 days and had evidence of spontaneous echo contrast (SEC) or LAA thrombus on TEE. Clinical, demographic, and echo data were collected. Prospective analysis of the CTA for evidence of LAA thrombus in the same group of patients was performed. We compared the findings of the two modalities.

RESULTS

Out of 1550 patients with atrial fibrillation who underwent TEE examinations in the study period, 63 patients underwent TEE within 30 days of a chest CTA scan. Twenty-three patients had LAA thrombus and 40 had some degree of SEC according to TEE. On CTA, 11 were interpreted as positive with a high level of suspicion for the presence of an LAA thrombus. Six patients (26.1%) had LAA thrombus according to both CT and TEE. Therefore, low concordance was found between test results (chi-squared continuity correction = 5.5, df  = 1, and P -value = 0.01902).

CONCLUSION

The discrepancy between CTA and TEE results suggests these examinations might be more suitable as complementary examinations to exclude LAA thrombus.

3D transesophageal echocardiography assists in evaluating the morphology, function, and presence of thrombi of left atrial appendage in patients with atrial fibrillation

Background

Left atrial appendage (LAA) is significantly more likely to form thrombi in patients with atrial fibrillation (AFib). Two-dimensional transesophageal echocardiography (2D TEE) is considered the gold standard for assessing and studying LAA morphology and anatomy. However, 2D TEE can only visualize one plane at any given time. Real-time three-dimensional echocardiography (RT-3D TEE) imaging can preserve spatial and temporal resolution, which is a safe, accurate, and reproducible imaging modality. There are few reports of the usage of RT-3D TEE to study LAA in AFib patients. In our research, RT-3D TEE helps to provide detailed LAA information and identifying the presence or absence of thrombi from pectinate muscles in paroxysmal and long-standing AFib patients.

Methods

LAA morphology was analyzed in detail by 2D TEE and RT-3D TEE in 320 patients with paroxysmal or long-standing AFib. The LAA flow pattern, as maximal LAA emptying flow velocity (LAAeV), was retrieved from 2D and 3D TEE imaging. LAA morphological parameters, spontaneous echo contrast (SEC), and thrombi were also detected by 2D and 3D TEE in all patients. In addition, LAA lobes and types were classified according to the morphology by 3D TEE, and the relationship between LAA types and the incidence of thrombi was evaluated.

Results

Long-standing AFib had greater enlargement of LAAs (orifice diameters and area), significantly more severe SEC, and a higher thrombi clot incidence rate by 3D-TEE compared with paroxysmal AFib patients (P<0.05). In addition, cauliflower morphology in long-standing AFib patients was associated with a higher LAA thrombus (OR 2.1, 95% CI: 1.1–8.5, P=0.031) and increased prevalence of SEC. Moreover, the uncertainty of thrombi detection was significantly decreased by 3D TEE compared with 2D TEE (P<0.001), and the certainty of thrombi detection by 3D TEE also decreased slightly (P=0.06).

Conclusions

RT-3D TEE is a safe and real-time option for the evaluation of LAA morphology and function. Long-standing AFib has greater LAA and SEC, as well as a higher incidence of thrombi than the paroxysmal group. Cauliflower LAA type was associated with a higher prevalence of SEC and thrombi.

Clinical utility of echocardiography in secondary ischemic stroke prevention

Echocardiography employs ultrasound to evaluate cardiac function, structure and pathology. The clinical value in secondary ischemic stroke prevention depends on identification of associated conditions for which a change in treatment from antiplatelet agents and risk factor intervention leads to improved outcomes. Such therapeutically relevant findings include primarily intracardiac thrombus, valvular heart disease and, in highly selected patients, patent foramen ovale (PFO). Echocardiography in unselected patients with ischemic stroke has a very low yield of therapeutically relevant findings and is not cost-effective. With the exception of PFO, findings on echocardiography that are therapeutically relevant for secondary stroke prevention are almost always associated with history, signs or symptoms of cardiac or systemic disease. Choice of specific echocardiographic modalities should be based on the specific pathology or pathologies that are under consideration for the individual clinical situation. Transthoracic echocardiography (TTE) with agitated saline has comparable accuracy to transesophageal echocardiography (TEE) for PFO detection. For other therapeutically relevant pathologies, with the possible exception of left ventricular thrombus (LVT), TEE is more sensitive than TTE. Professional societies recommend TTE as the initial test but these recommendations do not take cost into account. In contrast, cost-effectiveness studies have determined that the most sensitive echocardiographic modality should be selected as the initial and only test.

Characteristics of Anatomy and Function of the Left Atrial Appendage and Their Relationships in Patients with Cardioembolic Stroke: A 3-Dimensional Transesophageal Echocardiography Study

BACKGROUND

Increasing attention is being paid to the left atrial appendage (LAA) in the context of risk stratification in cardioembolic stroke (CES) and the requirement for meticulous planning of percutaneous closure device implantation. However, detailed systematic assessment of the LAA remains limited.

METHODS

This study evaluated the anatomy and function of LAA using 3-dimensional transesophageal echocardiography (3D-TEE) on 194 consecutive patients older than 50 years old hospitalized exclusively for CES. Patients were stratified into 3 groups on the basis of cardiac rhythm: (1) chronic atrial fibrillation (AF), n = 53; (2) paroxysmal AF, n = 26; and (3) no detected AF, n = 115.

RESULTS

Significant differences between the groups were observed for anatomical (orifice area [OA], depth, diastolic volume) and functional parameters (ejection fraction [EF], flow velocity [FV]), as measured by 3D-TEE. The anatomical parameters were consistently the greatest, and functional parameters were the poorest, in the group with chronic AF. There were significant inverse correlations between them (r = -.33, P = .0003 for depth and EF; r = -.27, P = .0020 for depth and FV; r = -.22, P = .016 for OA and EF; and r = -.38, P < .0001 for OA and FV).

CONCLUSIONS

LAA morphology and function were strongly affected by cardiac rhythm disturbances. Patients with chronic AF had the greatest LAA dimensions, areas, and volumes as well as the lowest LAA functions. An inverse correlation was observed between LAA size and function.

Rotational method simplifies 3-dimensional measurement of left atrial appendage dimensions during transesophageal echocardiography

Background

Not all echo laboratories have the capability of measuring direct online 3D images, but do have the capability of turning 3D images into 2D ones “online” for bedside measurements. Thus, we hypothesized that a simple and rapid rotation of the sagittal view (green box, x-plane) that shows all needed left atrial appendage (LAA) number of lobes, orifice area, maximal and minimal diameters and depth parameters on the 3D transesophageal echocardiography (3DTEE) image and LAA measurements after turning the images into 2D (Rotational 3DTEE/“Yosefy Rotation”) is as accurate as the direct measurement on real-time-3D image (RT3DTEE).

Methods

We prospectively studied 41 consecutive patients who underwent a routine TEE exam, using QLAB 10 Application on EPIQ7 and IE33 3D-Echo machine (BORTHEL Phillips) between 01/2013 and 12/2015. All patients underwent 64-slice CT before pulmonary vein isolation or for workup of pulmonary embolism. LAA measurements were compared between RT3DTEE and Rotational 3DTEE versus CT.

Results

Rotational 3DTEE measurements of LAA were not statistically different from RT3DTEE and from CT regarding: number of lobes (1.6 ± 0.7, 1.6 ± 0.6, and 1.4 ± 0.6, respectively, p = NS for all); internal area of orifice (3.1 ± 0.6, 3.0 ± 0.7, and 3.3 ± 1.5 cm², respectively, p = NS for all); maximal LAA diameter (24.8 ± 4.5, 24.6 ± 5.0, and 24.9 ± 5.8 mm, respectively, p = NS for all); minimal LAA diameter (16.4 ± 3.4, 16.7 ± 3.3, and 17.0 ± 4.4 mm, respectively, p = NS for all), and LAA depth (20.0 ± 2.1, 19.8 ± 2.2, and 21.7 ± 6.9 mm, respectively, p = NS for all).

Conclusion

Rotational 3DTEE method for assessing LAA is a simple, rapid and feasible method that has accuracy similar to that of RT3DTEE and CT. Thus, rotational 3DTEE (“Yosefy rotation”) may facilitate LAA closure procedure by choosing the appropriate device size.

A New Method for Direct Three-Dimensional Measurement of Left Atrial Appendage Dimensions during Transesophageal Echocardiography

AIMS

Currently, two-dimensional transesophageal echocardiography (2DTEE) at a cut-plane angulation of 135° is the recommended method to size maximal left atrial appendage (LAA) orifice diameter before introducing a percutaneous LAA closure device. We compared real time three-dimensional TEE (RT3DTEE) and 2DTEE for measuring LAA dimensions versus computed tomography (CT) as gold standard.

METHODS AND RESULTS

We prospectively studied 30 consecutive patients who underwent a routine TEE examination, using QLAB 10.0 Application on EPIQ7 iE33 3D echo machine between December 2012 and December 2013. All patients underwent 64-slice CT before pulmonary vein isolation or for workup of pulmonary embolism. LAA measurements were compared between 135 2DTEE and RT3DTEE. Results were compared with CT measurements. Using RT3DTEE, larger LAA diameters were measured versus 2DTEE (23.5 ± 3.9 vs. 24.5 ± 4.7 mm). In seven patients (23.3%), the measurements in 135° 2DTEE were smaller than the cut-plane angulation with maximal orifice diameter. RT3DTEE measurements of LAA were not different from CT regarding number of lobes, area of orifice, and maximal diameter. LAA volume could not be measured directly using RT3DTEE. No difference was found between LAA depth using RT3DTEE (19.5 ± 2.3 mm) vs. CT (19.6 ± 2.3, P = NS) and 2DTEE (19.4 ± 2.2 mm) vs. CT (P = NS). However, RT3DTEE (24.5 ± 4.7 mm) vs. CT (24.6 ± 5, P = NS) was more accurate in measuring maximal LAA diameter compared to 2DTEE (23.5 ± 3.9 mm) vs. CT (P < 0.01).

CONCLUSION

RT3DTEE method is more accurate than 2DTEE for assessment of maximal LAA orifice diameter. Bedsides, RT3DTEE LAA measurements are not statistically different from CT. Thus, RT3DTEE may facilitate LAA closure procedure by choosing the appropriate device size.