Transcutaneous detection of aortic arch atheromas by suprasternal harmonic imaging

Aortic Arch Plaques and the Long-Term Risk of Stroke and Cardiovascular Events in the Statin Era

BACKGROUND

Aortic arch plaques are associated with an increased risk of ischemic stroke in patients with cryptogenic stroke or prior embolic events. However, this relationship is unclear in the community. We investigated (1) the long-term risk of stroke and cardiovascular events associated with arch plaques and (2) whether statin therapy prescribed for any indication modified the association.

METHODS

A total of 934 stroke-free participants (72±9 years; 37% men) from the CABL study (Cardiovascular Abnormalities and Brain Lesion) were evaluated. Arch plaques were assessed by suprasternal transthoracic echocardiography; plaques ≥4 mm in thickness were classified as large plaques. The primary outcome was ischemic stroke; the secondary outcome was combined cardiovascular events (ischemic stroke, myocardial infarction, and cardiovascular death). The plaque-related risk of outcomes was also analyzed according to the presence of statin treatment. No plaque was used as a reference.

RESULTS

Aortic arch plaques were present in 645 participants (69.1%), with large plaques in 114 (12.2%). During a mean follow-up of 11.3±3.6 years, 236 (25.3%) cardiovascular events occurred (76 ischemic strokes, 27 myocardial infarctions, and 133 cardiovascular deaths). Large arch plaques were independently associated with combined events (adjusted hazard ratio, 2.19 [95% CI, 1.40-3.43]) but not stroke alone (adjusted hazard ratio, 1.09 [95% CI, 0.50-2.38]). The association between large plaques and cardiovascular events was significant in participants receiving statins (adjusted hazard ratio, 2.57 [95% CI, 1.52-4.37]) but not in others; however, participants on statin treatment also had a worse risk profile (higher body mass index, greater frequencies of hypertension, diabetes, and coronary artery disease).

CONCLUSIONS

Aortic arch plaques may be a marker of cardiovascular risk rather than a direct embolic stroke source in older adults without prior stroke. The efficacy of broader cardiovascular risk factors control, beyond cholesterol levels alone, for primary prevention of cardiovascular events in individuals with aortic arch plaques may require further investigation.

Imaging Biomarkers and Prevalence of Complex Aortic Plaque in Cryptogenic Stroke: A Systematic Review

BACKGROUND

Complex aortic plaque (CAP) is a potential embolic source in patients with cryptogenic stroke (CS). We review CAP imaging criteria for transesophageal echocardiogram (TEE), computed tomography angiography (CTA), and magnetic resonance imaging and calculate CAP prevalence in patients with acute CS.

METHODS AND RESULTS

PubMed and EMBASE databases were searched up to December 2022 in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline. Two independent reviewers extracted data on study design, imaging techniques, CAP criteria, and prevalence. The Cochrane Collaboration tool and Guideline for Reporting Reliability and Agreement Studies were used to assess risk of bias and reporting completeness, respectively. From 2293 studies, 45 were reviewed for CAP imaging biomarker criteria in patients with acute CS (N=37 TEE; N=9 CTA; N=6 magnetic resonance imaging). Most studies (74%) used ≥4 mm plaque thickness as the imaging criterion for CAP although ≥1 mm (N=1, CTA), ≥5 mm (N=5, TEE), and ≥6 mm (N=2, CTA) were also reported. Additional features included mobility, ulceration, thrombus, protrusions, and assessment of plaque composition. From 23 prospective studies, CAP was detected in 960 of 2778 patients with CS (0.32 [95% CI, 0.24-0.41], I2=94%). By modality, prevalence estimates were 0.29 (95% CI, 0.20-0.40; I2=95%) for TEE; 0.23 (95% CI, 0.15-0.34; I2=87%) for CTA and 0.22 (95% CI, 0.06-0.54; I2=92%) for magnetic resonance imaging.

CONCLUSIONS

TEE was commonly used to assess CAP in patients with CS. The most common CAP imaging biomarker was ≥4 mm plaque thickness. CAP was observed in one-third of patients with acute CS. However, high study heterogeneity suggests a need for reproducible imaging methods.

Long term aortic arch plaque progression in older adults

Background and aims

The presence of aortic arch plaques (AAP) is significantly associated with increased cardiovascular morbidity and mortality. Few studies have examined the incidence of AAP progression and factors which may contribute to it using transthoracic echocardiography (TTE). The objective of this study was to utilize sequential imaging of the aortic arch using TTE to examine the rate of AAP progression and its risk factors in a cohort of older adults.

Methods

Participants enrolled in both the Cardiovascular Abnormalities and Brain Lesion study (years 2005-2010) and the Subclinical Atrial Fibrillation and Risk of Ischemic Stroke study (2014-2019) who underwent TTE with assessment of aortic arch plaques at both time points represent the study cohort.

Results

300 participants were included in the study. Mean age was 67.8 ± 7.5 years at baseline, and 76.7 ± 6.8 years at follow-up; 197 (65.7%) were women. At baseline, 87 (29%) had no significant AAP, 182 (60.7%) had evidence of small AAP (2.0-3.9 mm) and 31 (10.3%) had evidence of large (≥4 mm) AAP. At the time of follow-up assessment, 157 (52.3%) of participants exhibited progression of AAP with 70 (23.3%) having mild progression and 87 (29%) having severe progression. There were no significant demographic or clinical predictors of AAP progression except baseline plaque thickness itself which was significantly lower in the group with AAP progression.

Conclusions

Our study demonstrates a high prevalence of AAP on TTE exam in a population-based cohort of older adults with a high incidence of AAP progression. TTE is a useful test for baseline and follow up imaging of AAP, even in subjects with no or little AAP at baseline.

Towards personalized antithrombotic management with drugs and devices across the cardiovascular spectrum

Intravascular thrombus formation and embolization are among the most frequent events leading to a number of cardiovascular conditions with high morbidity and mortality. The underlying causes are stasis of the circulating blood, genetic and acquired coagulation disorders, and reduced antithrombotic or prothrombotic properties of the vascular wall (Virchow's triad). In the venous system, intravascular thrombi can cause venous thrombosis and pulmonary and even peripheral embolism including ischaemic stroke [through a patent foramen ovale (PFO)]. Thrombi in the left atrium and its appendage or ventricle form in the context of atrial fibrillation and infarction, respectively. Furthermore, thrombi can form on native or prosthetic aortic valves, within the aorta (in particular at sites of ulcers, aortic dissection, and abdominal aneurysms), and in cerebral and peripheral arteries causing stroke and critical limb ischaemia, respectively. Finally, thrombotic occlusion may occur in arteries supplying vital organs such the heart, brain, kidney, and extremities. Thrombus formation and embolization can be managed with anticoagulants and devices depending on where they form and embolize and on patient characteristics. Vitamin K antagonists are preferred in patients with mechanical valves, while novel oral anticoagulants are first choice in most other cardiovascular conditions, in particular venous thromboembolism and atrial fibrillation. As anticoagulants are associated with a risk of bleeding, devices such as occluders of a PFO or the left atrial appendage are preferred in patients with an increased bleeding risk. Platelet inhibitors such as aspirin and/or P2Y12 antagonists are preferred in the secondary prevention of coronary artery disease, stroke, and peripheral artery disease either alone or in combination depending on the clinical condition. A differential and personalized use of anticoagulants, platelet inhibitors, and devices is recommended and reviewed in this article.

EACVI recommendations on cardiovascular imaging for the detection of embolic sources: endorsed by the Canadian Society of Echocardiography

Cardioaortic embolism to the brain accounts for approximately 15-30% of ischaemic strokes and is often referred to as 'cardioembolic stroke'. One-quarter of patients have more than one cardiac source of embolism and 15% have significant cerebrovascular atherosclerosis. After a careful work-up, up to 30% of ischaemic strokes remain 'cryptogenic', recently redefined as 'embolic strokes of undetermined source'. The diagnosis of cardioembolic stroke remains difficult because a potential cardiac source of embolism does not establish the stroke mechanism. The role of cardiac imaging-transthoracic echocardiography (TTE), transoesophageal echocardiography (TOE), cardiac computed tomography (CT), and magnetic resonance imaging (MRI)-in the diagnosis of potential cardiac sources of embolism, and for therapeutic guidance, is reviewed in these recommendations. Contrast TTE/TOE is highly accurate for detecting left atrial appendage thrombosis in patients with atrial fibrillation, valvular and prosthesis vegetations and thrombosis, aortic arch atheroma, patent foramen ovale, atrial septal defect, and intracardiac tumours. Both CT and MRI are highly accurate for detecting cavity thrombosis, intracardiac tumours, and valvular prosthesis thrombosis. Thus, CT and cardiac magnetic resonance should be considered in addition to TTE and TOE in the detection of a cardiac source of embolism. We propose a diagnostic algorithm where vascular imaging and contrast TTE/TOE are considered the first-line tool in the search for a cardiac source of embolism. CT and MRI are considered as alternative and complementary tools, and their indications are described on a case-by-case approach.

The role of echocardiography in the embolic stroke of undetermined source

: Echocardiography plays an important role both in the diagnosis and the treatment/prevention of embolic stroke of undetermined source and should be performed as soon as possible for preventing ischemic stroke recurrencies, which occur more frequently during the first week after the first ischemic event. Early identification of the cause of a transient ischemic attack or stroke is indeed a primary goal for the neurologist in the Stroke Unit and requires specific diagnostic strategies. Echocardiography, together with other diagnostic tools such as carotid and transcranial ultrasounds, provides this information promptly. In particular, echocardiography might be able to detect the main sources of the embolic stroke, such as atrial fibrillation, ventricular akinesia, aortic atheroma plaques and/or cardiac shunts. The present review discusses the importance and the practical role of echocardiography as a crucial diagnostic tool for detecting the main source of emboli in the setting of the acute stroke.

Aortic Sources of Embolism

Aortic arch atheroma is a frequent finding in ischemic stroke patients. Its role as a source of cerebral emboli or a marker of atherosclerosis is unclear. Transesophageal echography is considered the gold standard for its detection, whereas computed tomography angiography is a good alternative; magnetic resonance and positron emission tomography could be proposed to better analyze plaque vulnerability. Despite the interest in this condition, the optimal antithrombotic treatment remains uncertain, while intensive lipid-lowering therapy should be recommended. This review aims to offer guidance on patients with aortic arch atheroma, about its causal role in stroke, diagnosis, and treatment based on current available evidence.

Experimental evaluation of ultrasound higher-order harmonic imaging with Filtered-Delay Multiply And Sum (F-DMAS) non-linear beamforming

Tissue Harmonic Imaging (THI) mode is currently one of the preferred choices by the clinicians for its ability to provide enhanced ultrasound images, thanks to the use of the second harmonic component of backscattered echoes. This paper aims at investigating whether the combination of THI with Filtered-Delay Multiply And Sum (F-DMAS) beamforming can provide further improvements in image quality. F-DMAS is a new non-linear beamformer, which, similarly to THI, is based on the use of the second harmonics of beamformed signals and is known to increase image contrast resolution and noise rejection. Thus, we have first compared the images obtained by using F-DMAS and the standard Delay And Sum (DAS) beamformers when only the second harmonics of the received signals was selected. Moreover, possible improvements brought about by other harmonic components generated by the combined use of the fundamental plus second harmonics and F-DMAS beamforming have been explored. Experimental results demonstrate that, as compared to standard harmonic imaging with DAS, THI and F-DMAS can be joined to improve the -20 dB lateral resolution up to 1 mm, the contrast ratio up to 12 dB on a cyst-phantom and up to 9 dB on in vivo images.

Guidelines for the Use of Echocardiography in the Evaluation of a Cardiac Source of Embolism

Embolism from the heart or the thoracic aorta often leads to clinically significant morbidity and mortality due to transient ischemic attack, stroke or occlusion of peripheral arteries. Transthoracic and transesophageal echocardiography are the key diagnostic modalities for evaluation, diagnosis, and management of stroke, systemic and pulmonary embolism. This document provides comprehensive American Society of Echocardiography guidelines on the use of echocardiography for evaluation of cardiac sources of embolism. It describes general mechanisms of stroke and systemic embolism; the specific role of cardiac and aortic sources in stroke, and systemic and pulmonary embolism; the role of echocardiography in evaluation, diagnosis, and management of cardiac and aortic sources of emboli including the incremental value of contrast and 3D echocardiography; and a brief description of alternative imaging techniques and their role in the evaluation of cardiac sources of emboli. Specific guidelines are provided for each category of embolic sources including the left atrium and left atrial appendage, left ventricle, heart valves, cardiac tumors, and thoracic aorta. In addition, there are recommendation regarding pulmonary embolism, and embolism related to cardiovascular surgery and percutaneous procedures. The guidelines also include a dedicated section on cardiac sources of embolism in pediatric populations.

Atherosclerotic Plaques in the Aortic Arch and Subclinical Cerebrovascular Disease

BACKGROUND AND PURPOSE

Aortic arch plaque (AAP) is a risk factor for ischemic stroke, but its association with subclinical cerebrovascular disease is not established. We investigated the association between AAP and subclinical cerebrovascular disease in an elderly stroke-free community-based cohort.

METHODS

The CABL study (Cardiovascular Abnormalities and Brain Lesions) was designed to investigate cardiovascular predictors of silent cerebrovascular disease in the elderly. AAPs were assessed by suprasternal transthoracic echocardiography in 954 participants. Silent brain infarcts and white matter hyperintensity volume (WMHV) were assessed by brain magnetic resonance imaging. The association of AAP thickness with silent brain infarcts and WMHV was evaluated by logistic regression analysis.

RESULTS

Mean age was 71.6±9.3 years; 63% were women. AAP was present in 658 (69%) subjects. Silent brain infarcts were detected in 138 participants (14.5%). In multivariate analysis adjusted for potential confounders, AAP thickness and large AAP (≥4 mm in thickness) were significantly associated with the upper quartile of WMHV (WMHV-Q4; odds ratio =1.17; 95% confidence interval, 1.04-1.32; P=0.009 and odds ratio =1.79; 95% confidence interval, 1.40-3.09; P=0.036, respectively), but not with silent brain infarcts (odds ratio =1.08; 95% confidence interval, 0.94-1.23; P=0.265 and odds ratio =1.46; 95% confidence interval, 0.77-2.77; P=0.251, respectively).

CONCLUSIONS

Aortic arch atherosclerosis was associated with WMHV in a stroke-free community-based elderly cohort. This association was stronger in subjects with large plaques and independent of cardiovascular risk factors. Aortic arch assessment by transthoracic echocardiography may help identify subjects at higher risk of subclinical cerebrovascular disease, who may benefit from aggressive stroke risk factors treatment.

Aortic Complex Plaque Predicts the Risk of Cryptogenic Ischemic Cerebrovascular Disease Recurrence

To evaluate the correlations between aortic complex plaque (ACP) and the recurrence of cryptogenic ischemic cerebrovascular disease (CICVD), and to investigate the clinical significance of ACP in CICVD. Methods CICVD patients (aged 17 to 84 years) admitted into the Department of Neurology, Xuanwu Hospital, from July 2011 to December 2013, were consecutively recruited, and divided into ACP and non-ACP groups according to head and neck computerized tomographic (CT) angiography. Recurrences of cerebral ischemic events (CIEs) were compared between these groups after follow-up. Results A total of 117 patients were enrolled (ACP group: 69, non-ACP group: 48) and followed up for a mean of 9.86 months (range: 3-33). The average age of the ACP group was 62.88 years, with 59.4% older than 60 years; the average age of the non-ACP group was 50.29 years, with 37.5% older than 60 years. At the 6-month follow-up, the recurrence rate of CIEs in the ACP group was significantly higher than that of the non-ACP group (17.0% [7/47] and 0% [0/36], respectively; χ2 = 4.283, P = 0.046). The cumulative recurrence risk for CIEs of the ACP group was significantly higher than for the non-ACP group (P = 0.004). Multivariate Cox survival analysis showed that ACP presence was an independent risk factor for CIE recurrence for CICVD patients (relative risk [RR] = 7.803, 95% confidence interval [CI], 1.827~33.319, P = 0.006). Conclusions ACP increased the recurrence risk of CIE in CICVD, and elderly CICVD patients should receive greater attention regarding the significance of ACP in recurrent CICVD.

Haemodynamical stress in mouse aortic arch with atherosclerotic plaques: Preliminary study of plaque progression

Atherosclerotic plaques develop at particular sites in the arterial tree, and this regional localisation depends largely on haemodynamic parameters (such as wall shear stress; WSS) as described in the literature. Plaque rupture can result in heart attack or stroke and hence understanding the development and vulnerability of atherosclerotic plaques is critically important. The purpose of this study is to characterise the haemodynamics of blood flow in the mouse aortic arch using numerical modelling. The geometries are digitalised from synchrotron imaging and realistic pulsatile blood flow is considered under rigid wall assumptions. Two cases are considered; arteries with and without plaque. Mice that are fed under fat diet present plaques in the aortic arch whose size is dependent on the number of weeks under the diet. The plaque distribution in the region is however relatively constant through the different samples. This result underlines the influence of the geometry and consequently of the wall shear stresses for plaque formation with plaques growing in region of relative low shear stresses. A discussion of the flow field in real geometry in the presence and absence of plaques is conducted. The presence of plaques was shown to alter the blood flow and hence WSS distribution, with regions of localised high WSS, mainly on the wall of the brachiocephalic artery where luminal narrowing is most pronounced. In addition, arch plaques are shown to induce recirculation in the blood flow, a phenomenon with potential influence on the progression of the plaques. The oscillatory shear index and the relative residence time have been calculated on the geometry with plaques to show the presence of this recirculation in the arch, an approach that may be useful for future studies on plaque progression.

The role of echocardiography in the management of the sources of embolism

The echocardiographic diagnosis of cardiac thrombi, vegetations and tumors as well as the identification of predisposing conditions such as patent foramen ovale, aortic atherosclerosis and other minor causes (e.g., mitral valve prolapse, mitral and aortic valve calcification) have crucial clinical relevance, affecting the choice of surgery and/or of pharmaceutical therapy in the setting of patients presenting embolism. The echocardiographic assessment helps not only for the retrospective diagnosis of sources of embolism but also for the prevention of events in asymptomatic patients. Echocardiography can also distinguish normal variants and artifacts from cardiac masses and tumors. Echocardiographic characterization/typology of cardiac sources of embolism is currently below par when compared with cardiac MRI, the current gold standard. Nevertheless, echocardiography remains the 'first-line' imaging tool, because of its low cost and the possibility to add easily available, functional and structural information at the patient's bedside.

Relationship between ambulatory blood pressure and aortic arch atherosclerosis

OBJECTIVE

Atherosclerotic plaque in the aortic arch is an independent risk factor for ischemic stroke. Although high blood pressure (BP) measured at the doctor's office is known to be associated with aortic atherosclerosis, little is known on the association between 24-h ambulatory BP and aortic arch plaque presence and severity. Our objective was to clarify the association between ambulatory BP variables and aortic arch atherosclerosis in a community-based cohort.

METHODS

The study population consisted of 795 patients (mean age 71 ± 9 years) participating in the Cardiovascular Abnormalities and Brain Lesions (CABL) study who underwent 24-h ambulatory BP monitoring (ABPM). Arch plaque was evaluated by 2D transthoracic echocardiography from a suprasternal window.

RESULTS

All systolic ABPM variables (24-h/daytime/nighttime mean systolic BP, daytime/nighttime systolic BP variability) were associated with the presence of any plaque and large (≥ 4 mm) plaque, whereas diastolic BP variables were not associated with aortic atherosclerosis. Multiple regression analysis indicated that nighttime systolic BP variability (expressed as the standard deviation of nighttime systolic BP) remained independently associated with large plaque after adjustment for age, sex, cigarette smoking, history of hypertension, diabetes mellitus, hypercholesterolemia, anti-hypertensive medication and nighttime mean systolic BP (odds ratio 1.39 per 1 standard deviation increase, 95% CI 1.00-1.93, P<0.05).

CONCLUSION

Systolic ABPM variables are significantly associated with the presence of arch plaque. Nighttime systolic BP variability is independently associated with large arch plaque. These findings may have important implications in gaining further insights into the mechanism of arch plaque formation and progression.

Aortic atheroma and adverse cerebral outcome: risk, diagnosis, and management options

Aortic atheromatous disease is a common finding in the patient presenting for cardiac surgery. Adverse neurologic outcome has been closely linked to the extent of aortic atherosclerosis. In order to optimize perioperative outcomes, the location and severity of disease needs accurate characterization using multimodal techniques. Although various preoperative radiographic techniques have variably identified patients with significant atheroma, intraoperative echocardiographic imaging has proven most useful in localizing and characterizing the degree of aortic atheroma. Epiaortic assessment of the ascending aorta has been utilized in guiding surgical modifications and interventions aimed at reducing the risk of neurologic injury. Although no particular technique has been definitely studied, avoidance of the identifiable atheromatous aortic region has been a main feature of the various modifications employed to optimize neurologic outcome after cardiac surgery.

Complex atheromatosis of the aortic arch in cerebral infarction

In many stroke patients it is not possible to establish the etiology of stroke. However, in the last two decades, the use of transesophageal echocardiography in patients with stroke of uncertain etiology reveals atherosclerotic plaques in the aortic arch, which often protrude into the lumen and have mobile components in a high percentage of cases. Several autopsy series and retrospective studies of cases and controls have shown an association between aortic arch atheroma and arterial embolism, which was later confirmed by prospectively designed studies. The association with ischemic stroke was particularly strong when atheromas were located proximal to the ostium of the left subclavian artery, when the plaque was ≥ 4 mm thick and particularly when mobile components are present. In these cases, aspirin might not prevent adequately new arterial ischemic events especially stroke. Here we review the evidence of aortic arch atheroma as an independent risk factor for stroke and arterial embolism, including clinical and pathological data on atherosclerosis of the thoracic aorta as an embolic source. In addition, the impact of complex plaques (≥ 4 mm thick, or with mobile components) on increasing the risk of stroke is also reviewed. In non-randomized retrospective studies anticoagulation was superior to antiplatelet therapy in patients with stroke and aortic arch plaques with mobile components. In a retrospective case-control study, statins significantly reduced the relative risk of new vascular events. However, given the limited data available and its retrospective nature, randomized prospective studies are needed to establish the optimal secondary prevention therapeutic regimens in these high risk patients.

The potential impact of contemporary transthoracic echocardiography on the management of patients with native valve endocarditis: a comparison with transesophageal echocardiography

BACKGROUND

Between 1987 and 1994, several studies demostrated transthoracic echocardiography (TTE) to be less sensitive than transesophageal echocardiography (TEE) in detecting native valve endocarditis. Recent technologic advances, especially the introduction of harmonic imaging and digital processing and storage, have improved TTE image quality. The aim of this study was to determine the diagnostic accuracy of contemporary TTE.

METHODS

Between 2003 and 2007, 75 patients underwent both TTE and TEE for clinically suspected infective endocarditis. The diagnostic accuracy of TTE was assessed using transesophageal echocardiography as the gold standard for diagnosis of endocarditis.

RESULTS

Of the 75 patients in this study, 33 were found to be positive by TEE. The sensitivity for detection of infective endocarditis by TTE was 81.8%. It provided good image quality in 81.5% of cases; in these patients sensitivity was even greater (89.3%).

CONCLUSION

Contemporary TTE has improved the diagnostic accuracy of infective endocarditis by ameliorating image quality; it provides an accurate assessment of endocarditis and may reduce the need for TEE.

Mitral annular calcification as a marker of complex aortic atheroma in patients with stroke of uncertain etiology

The aim of this study was to evaluate the presence of dense mitral annular calcification as a marker of complex aortic atherosclerosis in patients with stroke of uncertain etiology. One hundred twenty-one patients with stroke of uncertain etiology were evaluated for complex aortic atherosclerotic plaques; their presence and severity were correlated with transthoracic echocardiographic findings, demographic data, and cardiovascular risk factors. Complex plaques in the ascending aorta or aortic arch were found in 72 of the 121 patients (59.5%). The only difference seen in patients with or without plaques was the presence of dense mitral annular calcification (58.3 vs 16.3%; P < 0.001). Dense mitral annular calcification (n = 50) was associated with higher prevalence of complex aortic plaques (84.0% vs 42.3%; P < 0.001), mobile components (28.0% vs 9.9%; P < 0.01), and protruding (80.0% vs 36.6%; P < 0.001), ulcerated (16.0% vs 1.4%; P < 0.01), and multisite complex plaques (46.0% vs 9.0%; P < 0.001). Therefore, in patients with stroke of uncertain etiology dense mitral annular calcification is an important marker of aortic atherosclerosis with high risk of embolism, and this association may explain in part the high prevalence of stroke and peripheral embolism in patients with mitral annular calcification.

A novel acoustic window for trans-oesophageal echocardiography by using a saline-filled endotracheal balloon

BACKGROUND

The main structures anterior to the trachea are frequently poorly visualized by trans-oesophageal echocardiography (TEE) because of the tracheal air column. We studied a new acoustic window for TEE imaging of large vessels anterior to the trachea by using a saline-filled endotracheal balloon.

METHODS

Cardiac surgery patients were studied. After ventilation was discontinued at the beginning of cardiopulmonary bypass, a saline-filled latex balloon was inserted into the trachea through the tracheal tube. The structures anterior to the trachea were imaged with and without the endotracheal balloon. TEE images of the proximal aortic arch and innominate artery were classified into three grades according to the quality of images: 1, vessel not visible; 2, part of vessel wall visible; 3, entire vessel wall visible. Grade 3 was categorized as good visualization while grades 1 and 2 were categorized as inadequate. TEE images with and without balloon were compared using the Mann-Whitney U-test and Chi-square analysis. P<0.05 was considered statistically significant.

RESULTS

In 20 patients, 84% had good visualization of proximal aortic arch with presence of endotracheal balloon compared with 11% without (P<0.001). A total of 94% had good visualization of the proximal innominate artery with presence of endotracheal balloon compared with 0% without (P<0.001).

CONCLUSIONS

A new 'TEE trans-tracheal acoustic window' was established by usage of a saline-filled endotracheal balloon. This window partially eliminates the TEE blind zone and provides improved visualization of the proximal aortic arch and innominate artery.

Correlation between coronary artery disease and aortic arch plaque thickness measured by non-invasive B-mode ultrasonography

OBJECTIVE

Transesophageal echocardiography (TEE) has been used to visualize aortic arch plaques. TEE is moderately invasive. We employed a new non-invasive method for visualization of the aortic arch to assess the correlation of the extent of plaque in the aortic arch as visualized by non-invasive ultrasound with the prevalence of coronary artery disease (CAD).

METHODS

The aortic arch was examined with B-mode sonography using a right supraclavicular approach in 517 consecutive patients referred for carotid duplex sonography. CAD was defined as previous myocardial infarction, previous coronary revascularization or typical angina pectoris requiring treatment. Cardiovascular risk factors were documented.

RESULTS

The aortic arch could be visualized to measure intima-media thickness (IMT) in 97% of the 517 patients. The IMT was a strong predictor for the presence of CAD. Only 14% (37 out of 256) of patients with an IMT of <1.1 mm had overt CAD. The prevalence increased consistently with increase of IMT to 86% among the patients with IMT over 5 mm (chi2, p<0.0000001) (R=0.97, p<0.001). The average IMT increased also with age, diabetes mellitus, arterial hypertension, hypercholesterolemia and tobacco smoking.

CONCLUSIONS

Aortic arch IMT can be measured in the majority of patients using the right supraclavicular window. The method is non-invasive, allowing sequential examinations applicable to prospective studies of the risk of CAD.

Routine Transesophageal Echocardiography for the Evaluation of Cerebral Emboli in Elderly Patients

BACKGROUND

Approximately 20% of cerebral infarctions are cardioembolic in nature. Transesophageal echocardiography (TEE) is widely regarded as the initial study of choice for evaluating cardiac source of embolism. Although the majority of cerebrovascular accidents occur in elderly patients, the value of TEE in this population is poorly defined.

METHODS

We compared 491 patients older than 65 years with suspected embolic stroke or transient ischemic attack (TIA) who had undergone TEE evaluation between April 2000 and February 2004 to an age-, sex-, and time-matched control group that consisted of 252 patients. Studies were reviewed for abnormalities associated with thromboembolic disease.

RESULTS

The overall incidence of stroke risk factors was significantly higher in the study than in the control group. However, the four patients with left atrial thrombi had a history of atrial fibrillation. Although ascending and aortic arch sessile atheromata were observed more frequently in the study than control group, there were no significant differences in the incidence of either complex or mobile aortic atheromata. The incidence of atrial septal aneurysm was higher in the stroke/TIA group, but not in association with patent foramen ovale. Finally, there were also no differences in the incidence of spontaneous echocontrast, and/or patent foramen ovale between study and control groups.

CONCLUSIONS

We conclude: (1) There is a higher incidence of abnormalities implicated as sources of thromboembolic disease on TEE in elderly patients with cerebral infarctions, but (2) this incidence is driven by the presence of sessile aortic atheroma and atrial septal aneurysm. Until the benefits of specific therapies for these conditions are known, routine TEE in elderly patients with suspected embolic neurological events appears to be unwarranted.

L’apport de l’échocardiographie transœsophagienne au diagnostic des lésions emboligènes de l’aorte thoracique

Atherosclerotic plaques of the thoracic aorta are a well-recognized source of systemic embolism, especially cerebral embolism, in patients 60 years of age or older. The most helpful and readily available imaging technique to detect aortic plaques is transesophageal echocardiogram. Aortic plaques>4mm in thickness are the more likely to cause peripheral embolism. Moreover, plaque morphology is important to consider, since ulcerated plaques and plaques with mobile intra-aortic components ("debris") as well as hypoechoic and noncalcified plaques are at the higher risk of embolism. In addition to these common atherosclerotic lesions, rare cases of mobile thromboses of the aortic arch without aortic debris have been described in younger patients. Finally, a particular situation is that of cholesterol embolism following invasive intra-aortic maneuvers on atherosclerotic aortas. While the diagnosis of these lesions is well established, their management and treatment remain controversial.

Hypoechoic areas on ultrasound images of atheroma are not always diagnostic of fatty plaque

Atherosclerotic plaques in ultrasound (US) images may have bright areas suggestive of fibrous plaque and hypoechoic areas that are often interpreted as fatty plaque. The current study was designed to test the hypothesis that fibrous tissue in atherosclerotic plaques will be hyperechoic or hypoechoic, depending on collagen fiber morphology. Twelve segments of aortic arch containing atherosclerotic plaques obtained from cadavers were imaged with an 8-MHz US transducer, then sectioned, stained with picrosirius red and examined with polarized light microscopy. There were 12 bright areas that contained predominantly thick collagen fibers. Two areas were anechoic, with predominantly thin collagen fibers. There were 11 hypoechoic areas; six of these contained thin fibers and five contained no collagen on polarized light microscopy, suggesting fat or thrombus. We conclude that fibrous aortic plaques consisting of predominantly thin fibers appear hypoechoic or anechoic on US images and, therefore, may be indistinguishable from fatty plaques.

Impact of harmonic imaging on transthoracic echocardiographic identification of infective endocarditis and its complications

OBJECTIVE

To evaluate the comparative diagnostic value of harmonic imaging (HI) in the assessment of patients with suspected infective endocarditis (IE).

SETTING

Tertiary referral centre.

DESIGN

139 consecutive patients were evaluated with three imaging modalities: transthoracic echocardiography with fundamental imaging (FI); HI; and transoesophageal echocardiography (TOE). Image quality was assessed for each modality by semiquantitative scoring (0, poor, to 3, excellent). Presence, dimension, and characteristics of vegetations were assessed separately for each imaging modality, as well as presence of abscesses.

RESULTS

35 patients had definite IE. TOE was positive in 33 patients, HI in 28, and FI in 12 (p < 0.001 for FI v HI and v TOE). Mean image quality was 1.4 (0.7) for FI, 2.1 (0.6) for HI (p < 0.01 v FI), and 2.6 (0.4) for TOE (p < 0.001 v HI). The association between FI and TOE findings was Phi = 0.35 (chi2 = 17.57, p = 0.0014) and between HI and TOE it was Phi = 0.95 (chi2 = 125.72, p < 0.0001; p < 0.0001 v FI). The global echo score of vegetations was 7.1 (3.3) with FI, 8.5 (3.4) with HI, and 11.3 (3.9) with TOE (p < 0.001 v HI). Compared with TOE, FI identified only one of seven abscesses (sensitivity 14%) and HI identified two of seven abscesses (sensitivity 28%).

CONCLUSIONS

HI provides an accurate assessment of suspected IE. TOE achieves superior definition of IE related abnormalities.

Spiral computed tomography evidence of close correlation between coronary and thoracic aorta calcifications

Coronary calcium (CC) is invariably associated with coronary atherosclerosis and can be diagnosed noninvasively by fast spiral computed tomography (dual slice mode) (CT). Calcium is often deposited in the aorta as well, but the pathogenesis, correlates and clinical implications of calcification of the aorta are not yet elucidated. A possible association between the presence of CC and thoracic aorta calcification, as detected by spiral CT, has not been investigated yet. The goal of the present work was to examine by spiral CT whether an association exists between the presence of CC and thoracic aorta calcification in patients with high risk for atherosclerotic development. Four hundred and five patients with at least two risk factors for atherosclerosis were included (212 men and 193 women, age ranged 52-79 years). All underwent chest CT for CC and aortic calcification scoring. Calcifications' thickness of > or =5 mm was considered advanced. CC was documented in 294 patients (170 men, 124 women; mean age 66 +/- 6 years, range 55-78 years). The non-CC group (control) included 111 patients (42 men, 69 women; mean age 64 +/- 6 years, range 52-79 years). Significant differences were found between CC group and control for the presence of ascending aorta calcification (69% versus 36%, P < 0.001), and advanced calcification of > or =5mm (17% versus 4%, P < 0.001). Significant differences were also found between groups regarding the presence of descending aorta calcification (60% versus 38%, P < 0.001), and number of consecutive slices with calcification (18.8 +/- 12.4 versus 10.7 +/- 8.7, P < 0.01). We identified age (in decades) (OR 1.9, 95% CI 1. 2-3.0, P < 0.001), gender (female) (OR 0.4, 95% CI 0.2-0.6, P < 0.001), and thoracic aorta calcification (OR 2.9, 95% CI 1.7-5.0, P < 0.001) as the independent variables significantly associated with CC. Only age [odds ratio (OR) 3.05, 95% confidence interval (CI) 1.86-5.01, P < 0.001] and CC (OR 2.53, 95% CI 1.26-5.08, P = 0.006) were identified as independent variables for the prediction of thoracic aorta calcification.

CONCLUSIONS

Our study demonstrated a strong association of CC and calcification of the thoracic aorta on spiral CT.