Intraobserver and Interobserver Variability of Transesophageal Echocardiography in Aortic Arch Atheroma Measurement

doi:10.1016/j.echo.2007.08.019

Journal of the American Society of Echocardiography

Volume 21, Issue 2, February 2008, Pages 129-133

https://doi.org/10.1016/j.echo.2007.08.019 Get rights and content

Background

The risk of stroke associated with aortic arch atheroma is proportional to plaque thickness, the accurate measurement of which may influence future therapeutic decisions. Transesophageal echocardiography is the procedure of choice for plaque measurement. This study examines the reproducibility of such measurements within the context of the Aortic Arch Related Cerebral Hazard Trial of antithrombotic therapy.

Methods

Atheroma images were remeasured by 3 independent blinded observers of varying expertise. Intraobserver and interobserver variability were calculated using Lin’s concordance correlation coefficient (ρ-c), the Bland-Altman method, and the κ statistic.

Results

A total of 160 images were obtained from 96 patients (68% male; mean age 74 ± 9 years). Mean plaque thickness was 5.1 ± 2.3 mm, range 1.2 to 19.3 mm. For intraobserver variability, ρ-c = 0.95, mean difference = 0.01 mm, and κ = 0.71. For interobserver variability, ρ-c ranged from 0.80 to 0.91; mean difference was 0.13 to 0.48 mm; and κ was 0.61 to 0.69. By all statistical methods, agreement was at least substantial, although lower at greater plaque thicknesses. For the clinically relevant 4 mm, agreement was 84% to 88%.

Conclusions

Transesophageal echocardiography measurement of aortic plaque is substantially reproducible across a range of observer experience and, thus, is a widely applicable, adequately reliable tool for clinical and research purposes.

Section snippets

Patients and Measurements

TEE is routinely performed in all patients presenting to our institution with stroke that remains unexplained after clinical assessment, electrocardiography, and cerebrovascular imaging. Some of these patients are participating in the ARCH Trial. For the purposes of this study, 160 TEE images of the aortic arch from 96 patients were randomly selected from this cohort during a 12-month period to be subsequently remeasured by 3 different observers.

TEE Examination

Patients gave informed consent for the procedure.

Results

A total of 160 images were acquired from 96 patients (mean age 74 ± 9 years; 68% male). The mean plaque thickness derived from all measurements of all 160 images was 5.1 ± 2.3 mm, range 1.2 to 19.3 mm.

The comparisons among observers are summarized in Table.

Discussion

Although severe atheroma is a major risk factor for first and recurrent stroke, the optimal treatment strategy remains unclear. The ARCH Trial results will, therefore, be important in contributing to evidence-based management of this condition. However, for the findings to be widely applicable, TEE must be shown to be an appropriate and reliable screening tool for such patients, whether they are investigated in a dedicated stroke department at a tertiary institution or by a local cardiologist

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Large and/or complex atherosclerotic plaques in the proximal segment of the aorta have been identified as a cause of ischemic stroke in individuals older than age 60, initially in autopsy studies and then in vivo, using transesophageal echocardiography (TEE); TEE remains the most widely used diagnostic technique for their detection, although magnetic resonance imaging (MRI), computerized tomography (CT), and positron emission tomography (PET) are also used. The stroke risk depends on the morphologic characteristics of the plaque, which can be accurately assessed by TEE. Plaque thickness of 4 mm or greater is commonly used for risk stratification, although plaque complexity (i.e., presence of surface ulcerations and/or superimposed mobile components/thrombus) may be more directly related to the stroke mechanism. Unsuspected proximal aortic plaques increase the stroke risk during cardiac catheterization procedures and cardiac surgery due to the possibility of atheroembolism; screening for proximal aortic plaques is recommended in patients who have a high risk of significant aortic atherosclerotic disease, such as elderly patients and those with multiple atherosclerotic risk factors. Embolic protection during cardiac catheterization procedures and modification of the surgical approach may reduce the risk of embolic complications in these patients. The optimal preventive treatment to decrease embolic events in patients with proximal aortic plaques is controversial; statins and antiplatelet agents are currently recommended and are usually prescribed in patients with a recent stroke or transient ischemic attack; systemic anticoagulation appears indicated in the case of documented superimposed thrombus. Surgical aortic endarterectomy carries a great risk of embolization and should be reserved to highly selected cases. Advances in noninvasive imaging of plaques at higher risk of rupture and embolization (vulnerable plaque), along with newer potential medical treatment options, may further refine the approach to stroke prevention in patients with proximal aortic plaques.
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Citation Excerpt :
Zaidat et al. (2005) reported that TEE provides measurements of aortic plaque thickness and recognition of the morphologic characteristics of plaques with good reproducibility among inter- and intra-observers in stroke patients. Moreover, a recent study by Weber et al. (2008) assessed intra- and inter-observer variability for measurements of aortic plaque thickness by TEE in 160 images obtained from 96 patients. The authors concluded that this method is reproducible and is a widely applicable and reliable tool for clinical and research purposes.
Transesophageal echocardiography (TEE) is widely used for the evaluation of aortic arch atherosclerosis which carries an increased risk of ischemic stroke. We investigated the feasibility of simultaneous multi-plane imaging by real-time 3-D TEE for the assessment of aortic arch plaques. In 152 patients, we assessed aortic arch plaques and measured their maximum thickness by both conventional TEE imaging and multi-plane TEE imaging. There was excellent correlation and good agreement between the two methods in the measurement of the maximum thickness of arch plaques (r = 0.95, mean difference, −0.1 ± 0.5 mm). The mean image acquisition time required for aortic arch assessment by multi-plane imaging was significantly shorter than that required for conventional imaging in all patients (p < 0.001), especially those with complex plaques. These findings suggest that simultaneous multi-plane TEE imaging enables rapid and accurate evaluation of arch plaques and is therefore a useful tool for the assessment of aortic arch plaques in the clinical setting.
Comparison of computed tomography angiography and transesophageal echocardiography for evaluating aortic arch disease
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Aortic arch (AA) atheroma is a common source of artery-to-artery embolism. Identification of AA atherosclerotic disease is an important component of the embolic stroke workup. Transesophageal echocardiography (TEE) is the gold standard for AA evaluation, but it has associated risks and is not always readily available. Computed tomography angiography (CTA) is a rapid and noninvasive alternative. This study was conducted to compare the sensitivity and specificity of CTA and TEE for detecting AA disease. We performed a retrospective review of 250 consecutive patients at a tertiary stroke center who underwent both TEE and CTA within a 90-day period. We compared the presence and characteristics of AA plaques using a predetermined grading system for plaques in the ascending, transverse, and descending arch for both modalities (grades 1-4). Out of 750 AA segments (ascending, transverse, and descending AA in 250 patients), 494 were adequately imaged by CTA and TEE. The sensitivity of CTA in detecting grade 1-4 AA atheromas was 53%, and the specificity was 89%. For only high-grade atheromas, the specificity improved to 99%, but the sensitivity decreased to 23%. The negative predictive value of CTA for detection of AA atheromas was 60% (range 54%-65%) for all grades and 95% (range 92%-96%) for high-grade atheromas. CTA has a high negative predictive value for AA atheromas, especially for higher-grade atheromas, and thus may be a useful screening tool to exclude high-grade plaques, indicating a possible complementary role for CTA in detecting AA atheromas.
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Clinical investigationUltrasound in CV diseaseIntraobserver and Interobserver Variability of Transesophageal Echocardiography in Aortic Arch Atheroma Measurement

Background

Methods

Results

Conclusions

Section snippets

Patients and Measurements

TEE Examination

Results

Discussion

J Am Coll Cardiol

Lancet Neurol

J Am Coll Cardiol

Safety of transesophageal echocardiography; a multicenter survey of 10419 examinations

Circulation

Atherosclerotic disease of the aortic arch and the risk of ischemic stroke

N Engl J Med

Proximal aortic atheroma: an independent risk factor for cerebral ischemia

Stroke

Atherosclerotic disease of the aortic arch as a risk factor for recurrent ischemic stroke

N Engl J Med

Clinical investigation
Ultrasound in CV disease
Intraobserver and Interobserver Variability of Transesophageal Echocardiography in Aortic Arch Atheroma Measurement