Contrast enhanced transesophageal echocardiography in patients with atrial fibrillation referred to electrical cardioversion improves atrial thrombus detection and may reduce associated thromboembolic events

Incidence of left ventricular thrombus following STEMI in the modern era via multimodality imaging: A systematic review and meta-analysis

Background

Left ventricular thrombus (LVT) is a significant complication in STEMI. Previous studies were conducted prior to modern timely percutaneous reperfusion networks. Current expert opinion suggests incidence in the current era has decreased. We conducted a systematic review and meta-analysis to better understand the incidence and diagnosis of LVT in patients with STEMI treated with timely percutaneous techniques as assessed by multimodality imaging.

Methods

Cochrane, EMBASE, LILACS, and MEDLINE were searched over the last 10 years only including studies using contemporary techniques. The primary outcome was detection of LVT in patients via echocardiogram with or without contrast or Cardiac MRI (cMRI) following STEMI (both anterior and any territory) treated with PCI. Data was pooled across studies and statistical analysis was conducted via random effects model.

Results

31 studies were included. 18 studies included data on any territory STEMI, totaling 14,172 patients, and an incidence of 5.6% [95% CI 4.3-7.0]. 18 studies were included in analysis for anterior STEMI, totaling 7382 patients and incidence of 12.7% [95% CI 9.8-15.6]. Relative to cMRI as a gold standard, the sensitivity of non-contrast echocardiography to detect LVT was 58.2% [95% CI 46.6-69.2] with a specificity of 97.8% [95% CI 96.3-98.8].

Conclusions

Incidence of LVT in STEMI patients treated with contemporary timely percutaneous revascularization is in keeping with historical data and remains significant, suggesting this remains an ongoing issue for further investigation. Numerically, both cMRI and contrast echo detected more LVT compared to non-contrast echo in any-territory STEMI patients.

Contrast echocardiography: a practical guideline from the British Society of Echocardiography

Ultrasound contrast agents (UCAs) have a well-established role in clinical cardiology. Contrast echocardiography has evolved into a routine technique through the establishment of contrast protocols, an excellent safety profile, and clinical guidelines which highlight the incremental prognostic utility of contrast enhanced echocardiography. This document aims to provide practical guidance on the safe and effective use of contrast; reviews the role of individual staff groups; and training requirements to facilitate its routine use in the echocardiography laboratory.

Effectiveness of Transesophageal Echocardiography in Preventing Thromboembolic Complications Before Cardioversion: A Narrative Review

Atrial fibrillation (AFib) is one of the most prevalent irregular heartbeats that doctors encounter. Clinicians typically pursue two main approaches for treatment, namely, controlling the heart rate and managing the heart rhythm. Under the rhythm control approach, AFib is addressed through cardioversion, which is achieved either with medications termed pharmacological cardioversion (PCV) or via an electrical shock termed electric cardioversion (ECV). While ECV proves instrumental in AFib management, it carries its own risk factors, potentially leading to blood clot-related complications such as embolic strokes. To counteract this potential downside, a well-established strategy involves the utilization of transesophageal echocardiography (TEE) to identify possible embolic sources before initiating cardioversion. The goal of this systematic review is to highlight the role of TEE in preempting embolic occurrences following ECV during the management of AFib. After conducting a thorough search of databases, namely, PubMed, PubMed Central, and Medline, a total of 36 studies were selected for this review article. Following a comprehensive evaluation of these studies, it was concluded that TEE plays a pivotal role in preventing thromboembolic complications during ECV for AFib. However, it is important to note that further research is needed to delve deeper into this matter. While existing evidence underscores its efficacy, additional investigation is needed to address this subject matter comprehensively.

Where Is the Left Atrial Appendage Wall? Caution during Transesophageal Echocardiography

•High echoic partition could appear around the LAA wall. •The pericardium attached to the lung has very strong intensity reflection. •The pericardium attached to the lung mimics the LAA wall. •Reflection artifact could also mimic the LAA wall. •These phenomena should be considered when evaluating LAA morphology.

Transesophageal Echocardiogram Before Cardioversion in Atrial Fibrillation Patients

Transesophageal echocardiography (TEE) offers an invaluable, non-invasive avenue for diagnosing and managing various cardiac conditions, including atrial fibrillation (AF). As the most common cardiac arrhythmia, AF affects millions and can lead to severe complications. Cardioversion, a procedure to restore the heart's normal rhythm, is frequently conducted on AF patients resistant to medication. Due to inconclusive data, TEE's utility prior to cardioversion in AF patients remains ambiguous. Understanding TEE's potential benefits and limitations in this population could significantly influence clinical practice. This review aims to scrutinize the current literature on the use of TEE before cardioversion in AF patients. The principal objective is to understand TEE's potential benefits and limitations comprehensively. The study seeks to offer a clear understanding and practical recommendations for clinical practice, thereby improving the management of AF patients before cardioversion using TEE. A literature search of databases was conducted using the keywords "Atrial Fibrillation," "Cardioversion" and "Transesophageal echocardiography," resulting in 640 articles. These were narrowed to 103 following title and abstract reviews. After applying exclusion and inclusion criteria with a quality assessment, 20 papers were included: seven retrospective studies, 12 prospective observational studies, and one randomized controlled trial (RCT). Stroke risk associated with direct-current cardioversion (DCC) potentially results from post-cardioversion atrial stunning. Thromboembolic events occur post cardioversion, with or without prior atrial thrombus or cardioversion complications. Generally, cardiac thrombus localizes in the left atrial appendage (LAA), a clear contraindication to cardioversion. Atrial sludge without LAA thrombus in TEE is a relative contraindication. TEE before electrical cardioversion (ECV) in anticoagulated AF individuals is uncommon. In AF patients planned for cardioversion, contrast enhancement facilitates thrombus exclusion in TEE images, reducing embolic events. Left atrial thrombus (LAT) frequently occurs in AF patients, necessitating TEE examination. Despite the increased use of pre-cardioversion TEE, thromboembolic events persist. Notably, patients with post-DCC thromboembolic events had no LA thrombus or LAA sludge. The use of TEE-guided DCC has grown due to its ability to detect atrial thrombi pre-cardioversion, aiding risk stratification. Thrombus in the left atrium also signals an elevated risk of future thromboembolic events in AF patients. While atrial stunning post cardioversion detected by TEE is a significant risk factor for future thromboembolic events, further evidence is required. Therapeutic anticoagulation is essential during and post cardioversion, even if no atrial thrombus is detected. Current data recommends cardioversion guided by TEE, particularly in outpatient settings.

Preprocedural Multimodality Imaging in Atrial Fibrillation

Atrial fibrillation (AF) is the most common arrhythmia worldwide and is associated with increased risk of heart failure, stroke, and death. In current medical practice, multimodality imaging is routinely used in the management of AF. Twenty-one years ago, the ACUTE trial (Assessment of Cardioversion Using Transesophageal Echocardiography) results were published, and the management of AF changed forever by incorporating transesophageal echocardiography guided cardioversion of patients in AF for the first time. Current applications of multimodality imaging in AF in 2022 include the use of transesophageal echocardiography and computed tomography before cardioversion to exclude left atrial thrombus and in left atrial appendage occlusion device implantation. Transesophageal echocardiography, cardiac computed tomography, and cardiac magnetic resonance are clinically used for AF ablation planning. The decision to use a particular imaging modality in AF is based on patient's characteristics, guideline recommendation, institutional preferences, expertise, and cost. In this first of 2-part review series, we discuss the preprocedural role of echocardiography, computed tomography, and cardiac magnetic resonance in the AF, with regard to their clinical applications, relevant outcomes data and unmet needs, and highlights future directions in this rapidly evolving field.

The diagnostic accuracy of contrast echocardiography in patients with suspected cardiac masses: A preliminary multicenter, cross-sectional study

Background

To evaluate the diagnostic accuracy of contrast echocardiography (CE) in patients with suspected cardiac masses.

Methods

A multicenter, prospective study involving 108 consecutive patients with suspected cardiac masses based on transthoracic echocardiography performed between November 2019 and December 2020 was carried out. CE examinations were performed in all patients. The echocardiographic diagnosis was established according to the qualitative (echogenicity, boundary, morphology of the base, mass perfusion, pericardial effusion, and motility) and quantitative (area of the masses and peak intensity ratio of the masses and adjacent myocardium A1/A2) evaluations.

Results

Final confirmed diagnoses were as follows: no cardiac mass (n = 3), pseudomass (n = 3), thrombus (n = 36), benign tumor (n = 30), and malignant tumor (n = 36). ROC analysis revealed the optimal A1/A2 with cutoff value of 0.295 for a cardiac tumor from a thrombus, with AUC, sensitivity, specificity, PPV, and NPV of 0.958 (95% confidence interval (CI): 0.899–0.988), 100, 91.7, 95.7, and 100%, respectively. CE was able to distinguish malignant from benign tumors with an AUC of 0.953 (95% CI: 0.870–0.990). Multivariate logistic regression analysis revealed that tumor area, base, and A1/A2 were associated with the risk of malignant tumor (OR = 1.003, 95% CI: 1.00003–1.005; OR = 22.64, 95% CI: 1.30–395.21; OR = 165.39, 95% CI: 4.68–5,850.94, respectively). When using A1/A2 > 1.28 as the only diagnostic criterion to identify the malignant tumor, AUC, sensitivity, specificity, PPV, and NPV were 0.886 (95% CI: 0.784–0.951), 80.6, 96.7, 96.7, and 80.7%, respectively.

Conclusion

CE has the potential to accurately differentiate cardiac masses by combining qualitative and quantitative analyses. However, more studies with a large sample size should be conducted to further confirm these findings.

Clinical trial registration

http://www.chictr.org.cn/, identifier: ChiCTR1900026809.

Impact of ultrasound enhancing agents on clinical management

PURPOSE OF REVIEW

Ultrasound enhancing agents (UEAs), microbubbles which are composed of lipid or albumin shells containing high molecular weight gases with nonlinear acoustic properties in the ultrasound field, are important components of the diagnostic armamentarium in echocardiography. This review highlights the substantial value of UEAs in delineating endocardial border definition and influencing downstream decision-making in cardiovascular ultrasound.

RECENT FINDINGS

In this article, we review recent updates to the clinical applications of UEAs, special circumstances regarding use, the impact of use on downstream testing and cost-effectiveness, and recommended approaches for optimizing workflow in the echocardiography laboratory with UEAs.

SUMMARY

In multiple studies, UEAs have been identified as a useful tool in echocardiography, improving study accuracy and reader confidence, while reducing downstream testing and procedures and resulting in significant changes in clinical management. Despite their proven efficacy and cost-effectiveness, recent studies have suggested utilization remains low, in part due to perceived concerns and workflow issues that impair uptake. With an increasingly broader list of indications for echocardiography, UEAs will continue to play an important role in the diagnosis and management of patients with cardiovascular and noncardiovascular diseases.

Microbubble Enhanced Echocardiography in Current Cardiology Practice

Contrast-enhanced ultrasound imaging is a radiation-free clinical diagnostic tool that uses biocompatible contrast agents to enhance ultrasound signal, in order to improve image clarity and diagnostic performance. Ultrasound enhancing agents (UEA), which are usually gas microbubbles, are administered intravenously either by bolus injection or continuous infusion. UEA increase the accuracy and reliability of echocardiography, leading to changes in treatment, improving patient outcomes and lowering overall health care costs. In this review we describe: (1) the current clinical applications of ultrasound enhancing agents in echocardiography, with a brief review of the evidence underlying each of these applications; (2) emerging diagnostic and therapeutic applications of microbubble enhanced echocardiography (MEE), which rely either on the specific properties and composition of ultrasound enhancing agents or on the technical advances of clinical ultrasound systems; and (3) safety of MEE.

Current Guidelines on Management of Amaurosis Fugax and Transient Ischemic Attacks

ABSTRACT

Transient ischemic attack (TIA) is defined as a transient episode of neurological dysfunction resulting from focal brain, spinal cord, or retinal ischemia, without associated infarction. Consequently, a TIA encompasses amaurosis fugax (AF) that is a term used to denote momentary visual loss from transient retinal ischemia. In this review, we use the word TIA to refer to both cerebral TIAs (occurring in the brain) and AF (occurring in the retina). We summarize the key components of a comprehensive evaluation and management of patients presenting with cerebral and retinal TIA.All TIAs should be treated as medical emergencies, as they may herald permanent disabling visual loss and devastating hemispheric or vertebrobasilar ischemic stroke. Patients with suspected TIA should be expeditiously evaluated in the same manner as those with an acute stroke. This should include a detailed history and examination followed by specific diagnostic studies. Imaging of the brain and extracranial and intracranial blood vessels forms the cornerstone of diagnostic workup of TIA. Cardiac investigations and serum studies to evaluate for etiological risk factors are also recommended.The management of all TIAs, whether cerebral or retinal, is similar and should focus on stroke prevention strategies, which we have categorized into general and specific measures. General measures include the initiation of appropriate antiplatelet therapy, encouraging a healthy lifestyle, and managing traditional risk factors, such as hypertension, dyslipidemia, and diabetes. Specific management measures require the identification of a specific TIA etiology, such as moderate-severe (greater than 50% of stenosis) symptomatic extracranial large vessel or intracranial steno-occlusive atherosclerotic disease, aortic arch atherosclerosis, and atrial fibrillation.

A systematic review on the use of ultrasound enhancing agents with transesophageal echocardiography to assess the left atrial appendage prior to cardioversion

BACKGROUND

Assessment of the left atrium and atrial appendage (LAA) for thrombus by transesophageal echocardiography (TEE) may be suboptimal due to difficult imaging windows and ultrasound artifacts. The present study analyzed the benefit of using ultrasound enhancing agents (UEAs) with TEE to improve diagnostic accuracy and image quality.

METHODS

A systematic review of studies published through December 2020 was performed, and included investigations comparing the number of cases deemed indeterminate for visualization of LAA thrombi on TEE pre- versus post-UEAs prior to cardioversion for atrial fibrillation or flutter (AF). Study results were pooled where the number of indeterminate cases by conventional TEE were re-classified as thrombus present, indeterminate, or thrombus excluded following administration of UEAs.

RESULTS

Three studies with a total of 399 patients were identified. Of these, 83 (26%) participants met the inclusion criteria. The mean age of the study population from the three studies was 66 ± 12 years, 29% were female, and prevalence of congestive heart failure or neurologic events was 22% and 5%, respectively. Use of UEAs with TEE re-classified 66% (55/83) of cases initially deemed to be indeterminate for LAA thrombus on conventional TEE. Thrombus was present in 13% (11/83) and excluded in 53% (44/83) of cases; 34% (28/83) of cases remained indeterminate on TEE post-UEAs. There were no complications reported with the administration of UEAs.

CONCLUSION

Adjunctive use of UEAs with TEE can facilitate the diagnosis or exclusion of LAA thrombus, and improve the procedural confidence and cost-efficiency of cardioversion for AF.

Impact of ultrasound contrast agent during transoesophageal echocardiography on the sizing of the left atrial appendage

INTRODUCTION

Interventional closure of the left atrial appendage closure (LAAC) has been established as an alternative treatment in patients with atrial fibrillation (AF) and an increased risk of stroke. So far it is unknown whether the use of ultrasound contrast agent (UCA) would influence the correct sizing of the LAA and thereby have an impact on device selection during interventional LAAC.

METHODS

Between January 2017 and April 2018, 223 transoesophageal echocardiography (TOE) examinations were prospectively performed in adult patients with non-valvular AF (Impact of the use of ultrasound contrast agent on the detection of thrombi in the left atrial appendage during transesophageal echocardiography (CONDOR) study). LAA was examined both with and without the use of UCA. The following measurements were taken at 0^o, 45^o, 90^o and 135^o: diameter of LAA ostium, maximal depth of the LAA, maximal available depth of the LAA orthogonal to the ostial plane and area of the LAA.

RESULTS

The use of UCA had no relevant influence on the size determination of the LAA. Additionally, Bland-Altman blots demonstrate a high degree of correlation between the measurements with and without UCA with no evidence for a systematic effect arising from the use of UCA. When comparing the measurements of two independent investigators, the use of UCA rather leads to a higher variability than to an improved precision.

DISCUSSION

Despite the fact that the use of UCA during TOE leads to an improved rule out of thrombi, our study shows that there is no advantageous effect of UCA on the size determination of the LAA and should therefore not be used for this purpose.

Feasibility of ex vivo fluorescence imaging of angiogenesis in (non-) culprit human carotid atherosclerotic plaques using bevacizumab-800CW

Vascular endothelial growth factor-A (VEGF-A) is assumed to play a crucial role in the development and rupture of vulnerable plaques in the atherosclerotic process. We used a VEGF-A targeted fluorescent antibody (bevacizumab-IRDye800CW [bevacizumab-800CW]) to image and visualize the distribution of VEGF-A in (non-)culprit carotid plaques ex vivo. Freshly endarterectomized human plaques (n = 15) were incubated in bevacizumab-800CW ex vivo. Subsequent NIRF imaging showed a more intense fluorescent signal in the culprit plaques (n = 11) than in the non-culprit plaques (n = 3). A plaque received from an asymptomatic patient showed pathologic features similar to the culprit plaques. Cross-correlation with VEGF-A immunohistochemistry showed co-localization of VEGF-A over-expression in 91% of the fluorescent culprit plaques, while no VEGF-A expression was found in the non-culprit plaques (p < 0.0001). VEGF-A expression was co-localized with CD34, a marker for angiogenesis (p < 0.001). Ex vivo near-infrared fluorescence (NIRF) imaging by incubation with bevacizumab-800CW shows promise for visualizing VEGF-A overexpression in culprit atherosclerotic plaques in vivo.

Is transesophageal echocardiography necessary in patients undergoing ablation of atrial fibrillation on an uninterrupted direct oral anticoagulant regimen? Results from a prospective multicenter registry

BACKGROUND

Thromboembolic stroke is a rare but devastating consequence of atrial fibrillation (AF) ablation. Transesophageal echocardiography (TEE) is recommended to rule out left atrial appendage thrombus; however, its use is variable.

OBJECTIVE

The purpose of this study was to assess whether TEE is mandatory in patients undergoing AF ablation on uninterrupted direct oral anticoagulants (DOACs).

METHODS

Data from our prospective multicenter registry of patients with AF undergoing radiofrequency catheter ablation on uninterrupted DOACs were analyzed. All the included patients were on anticoagulation for at least 4 weeks before ablation. All AF ablation procedures were performed under intracardiac echocardiography guidance. Before transseptal puncture, heparin bolus was administered, followed by continuous infusion, with a target activated clotting time of >300 seconds.

RESULTS

A total of 6186 patients (3180 on apixaban [51.4%], 2528 on rivaroxaban [40.9%], 404 on dabigatran [6.5%], and 74 on edoxaban [1.2%]) were analyzed. The mean age of the study population was 69.4 ± 10.3 years; 4194 patients (67.8%) were male, and 5120 patients (82.8%) had persistent and long-standing persistent AF. The mean CHA₂DS₂-VASc score was 2.86 ± 1.58; the mean CHADS₂ score was 1.65 ± 1.14. Intracardiac echocardiography ruled out left atrial appendage and left atrial thrombi in all patients and revealed "smoke" in 1672 patients (27.03%). Transient ischemic attack was noted in 1 patient with long-standing persistent AF in the setting of a missed dose of rivaroxaban before ablation.

CONCLUSION

Our study showed that performing AF ablation in patients on uninterrupted DOACs without TEE is safe and feasible in high stroke risk patients. Elimination of routine preablation TEE would have significant economic and clinical implications.

Roles of Transesophageal Echocardiography and Cardiac Computed Tomography for Evaluation of Left Atrial Thrombus and Associated Pathology: A Review and Critical Analysis

Evaluation of the left atrium and left atrial appendage for the presence of thrombus prior to cardioversion and pulmonary vein isolation, and of the entire heart for embolic sources in the setting of cryptogenic stroke, has long been standard medical care. Guidelines have uniformly recommended transesophageal echocardiography (TEE) to accomplish these goals. In recent years, computed tomographic angiography has demonstrated diagnostic accuracy similar to that of TEE for the detection of thrombus. Analysis of the pertinent data and relative merits of the 2 technologies leads to the conclusions that: 1) both modalities have some unique, nonoverlapping capabilities that may dictate their use in specific situations; 2) computed tomographic angiography is a reasonable alternative to TEE when the primary aim is to exclude left atrial and left atrial appendage thrombus and in patients in whom the risks associated with TEE outweigh the benefits; and 3) both options should be discussed with the patient in the setting of shared decision making.

Impact of ultrasound contrast agent on the detection of thrombi during transoesophageal echocardiography

Background

Atrial fibrillation (AF) carries the risk of thrombus formation in the left atrium and especially in the left atrial appendage (LAA). A transoesophageal echocardiography (TOE) is routinely performed in these patients to rule out thrombi before cardioversion or structural interventions like LAA closure or pulmonary vein isolation. However, in a certain number of cases, inconclusive results of the TOE may result. This study was performed to analyse whether the routine use of ultrasound contrast agent (UCA) has an influence on the frequency of thrombus detection.

Methods

In patients with AF who were scheduled for a subsequent interventional procedure, a TOE was initially performed without contrast agent. Then, the TOE was repeated with the use of UCA. The percentage of diagnostic findings regarding the prevalence of thrombus in the LAA with and without UCA were compared (thrombus present (T+), no thrombus (T−) and inconclusive result (T+/−)).

Results

223 patients were prospectively included into the trial. The numbers of thrombus detection were as follows: without UCA: 17 T+ (7.6%), 154 T− (69.1%), 52 T+/− (23,3%); with UCA: 16 T+ (7.2%), 179 T− (80.3%), 28 T+/− (12.6%; χ²: p<0.01). In 29 examinations (13.0%), the use of UCA had an impact on the subsequent treatment strategy.

Conclusions

The use of UCA during TOE in patients with AF has a significant impact on the subsequent patient management especially due to an improved rule out of LAA thrombi.

[Not Available]

This literature review in devoted to the potential of application of contrast-enhanced echocardiography (CEE) for assessment of structure and function of left cardiac chambers. It contains based on current recommendations discussion of main indications for CEE and analysis of its possibilities in evaluation of perfusion of the left ventricular myocardium, detection of myocardial ischemia, and assessment of myocardial viability. Data on CEE safety and possible side effects associated with the use of ultrasound contrasts are also presented.

Clinical practice of contrast echocardiography: recommendation by the European Association of Cardiovascular Imaging (EACVI) 2017

Contrast echocardiography is widely used in cardiology. It is applied to improve image quality, reader confidence and reproducibility both for assessing left ventricular (LV) structure and function at rest and for assessing global and regional function in stress echocardiography. The use of contrast in echocardiography has now extended beyond cardiac structure and function assessment to evaluation of perfusion both of the myocardium and of the intracardiac structures. Safety of contrast agents have now been addressed in large patient population and these studies clearly established its excellent safety profile. This document, based on clinical trials, randomized and multicentre studies and published clinical experience, has established clear recommendations for the use of contrast in various clinical conditions with evidence-based protocols.

The Role of Echocardiography in Determining the Method of Ablation for the Treatment of Paroxysmal Atrial Fibrillation: A Literature Review

Atrial fibrillation is the most common cardiac arrhythmia, affecting approximately 1 out of every 250 people. It is associated with thrombus formation in the left atrium, decreased cardiac output, and deterioration of the myocardium. There are multiple treatments available for paroxysmal atrial fibrillation. This literature review will assess the benefits, risks, and complications associated with radiofrequency ablation and cryoablation, which utilize heat and freezing mechanisms, respectively. The review will also assess the role of echocardiography in determining which treatment, if any, is appropriate for atrial fibrillation.

Left atrial appendage pericardial fluid: contrast-enhanced transesophageal echocardiography makes it visible

BACKGROUND

Contrast-enhanced transesophageal echocardiography (TEE) for the opacification of left atrial appendage (LAA) is not clearly suggested by the current guidelines and only scarce data are available.

CASE PRESENTATION

A patient with a membrane-like structure in the LAA cavity is presented. Contrast-enhanced TEE revealed LAA pericardial effusion and this diagnosis was confirmed by cardiac magnetic resonance that offered comparable images and tissue characterization.

CONCLUSION

Contrast-enhanced TEE has been demonstrated to safely and accurately enlighten LAA anatomy. Hippokratia 2016, 20(3): 235-237.

Left atrial thrombi and spontaneous echo contrast in patients with atrial fibrillation : Systematic analysis of a single-center experience

BACKGROUND

Atrial fibrillation is associated with a high risk for thromboembolic events. Thrombi in the left atrial appendage and spontaneous echo contrast (SEC) correlate positively with this embolic risk. We studied the laboratory, echocardiographic, and epidemiologic parameters that could predict left atrial thrombi and the intensity of the SEC.

PATIENTS AND METHODS

Between September 2013 and June 2015 we included 372 patients with atrial fibrillation before planned electrical cardioversion (transesophageal-guided strategy) in this study. After assessing the risk of stroke and bleeding (CHA₂DS₂-VASc and HAS-BLED scores), we measured the concentration of the D-dimer and B-type natriuretic peptide at the time of the transesophageal echocardiography as well as the left atrial volume and the ejection fraction during transthoracic echocardiography.

RESULTS

The ejection fraction and the CHA₂DS₂-VASc score were identified as independent predictors of both left atrial thrombi and SEC, whereas the left atrial volume could only predict the intensity of SEC. In contrast to the results of other studies, the biomarkers in this study failed to predict the outcome.

CONCLUSION

Only the echocardiographic and epidemiologic parameters were predictors of left atrial thrombi and SEC intensity, while the studied biomarkers had no predictive power. Using clinical data and transthoracic echocardiography, we can change the therapeutic strategy in high-risk patients.

Percutaneous interventions for left atrial appendage exclusion: options, assessment, and imaging using 2D and 3D echocardiography

Percutaneous left atrial appendage (LAA) exclusion is an evolving treatment to prevent embolic events in patients with nonvalvular atrial fibrillation. In the past few years multiple percutaneous devices have been developed to exclude the LAA from the body of the left atrium and thus from the systemic circulation. Two- and 3-dimensional transesophageal echocardiography (TEE) is used to assess the LAA anatomy and its suitability for percutaneous closure to select the type and size of the closure device and to guide the device implantation procedure in conjunction with fluoroscopy. In addition, 2- and 3-dimensional TEE is also used to assess the effectiveness of device implantation acutely and on subsequent follow-up examination. Knowledge of the implantation options that are currently available along with their specific characteristics is essential for choosing the appropriate device for a given patient with a specific LAA anatomy. We present the currently available LAA exclusion devices and the echocardiographic imaging approaches for evaluation of the LAA before, during, and after LAA occlusion.

Prevalence of left atrial thrombus in patients with non-valvular atrial fibrillation. A systematic review and meta-analysis of the literature

We performed a meta-analysis about the prevalence of left atrial thrombus (LAT) in patients with atrial fibrillation (AF) undergoing trans-esophageal echocardiography (TEE). Studies reporting on LAT presence in AF patients were systematically searched in the PubMed, Web of Science, Scopus and EMBASE databases and the pooled LAT prevalence was evaluated as weighted mean prevalence (WMP). Seventy-two studies (20,516 AF patients) showed a LAT WMP of 9.8 % (95 %CI: 7.6 %-12.5 %). LAT presence was associated with a higher age (mean difference: 2.56, 95 %CI: 1.49-3.62), and higher prevalence of female gender (OR: 1.35, 95 %CI: 1.04-1.75), hypertension (OR: 1.78, 95 %CI: 1.38-2.30), diabetes mellitus (OR: 1.86, 95 %CI: 1.33-2.59) and chronic heart failure (OR: 3.67, 95 %CI: 2.40-5.60). Overall, LAT patients exhibited a higher CHADS2-score (mean difference 0.88, 95 %CI: 0.68-1.07) and a higher risk of stroke/systemic embolism (OR: 3.53, 95 %CI: 2.24-5.56) compared with those without LAT. A meta-regression showed an inverse association between LAT prevalence and the presence of anticoagulation (Z-value: -7.3, p< 0.001). Indeed, studies in which 100 % of patients received oral anticoagulation reported a 3.4 % WMP of LAT (95 %CI: 1.3 %-8.7 %), whereas studies in which 0 % of patients received anticoagulation showed a LAT WMP of 7.4 % (95 %CI: 2.3 %-21.5 %). Our data suggest that LAT is present in ≍10 % of AF patients, and is associated with a 3.5-fold increased risk of stroke/systemic embolism. Interestingly, LAT is also reported in some of patients receiving anticoagulation. The implementation of the screening of LAT in AF patients before cardioversion/ablation could be useful for the prevention of vascular events.

Contrast echocardiography: latest developments and clinical utility

Ultrasound enhancing agents (UEAs) are being utilized for a growing number of applications with real-time very low mechanical index (MI) techniques in clinical cardiology today. This article will review recent developments on the safety of UEAs and their effectiveness in myocardial perfusion imaging, three-dimensional quantification of left ventricular function, and vascular imaging. UEAs are now being utilized in all age groups, with new indications that add incremental value to the currently approved by the Food and Drug Administration. These include the incremental value in cardiac imaging, where the off-label analysis of myocardial perfusion observed with UEAs adds to the enhanced endocardial border delineation. In carotid artery imaging, UEAs improve the detection of plaque but also can examine plaque neovascularization. Vascular surgeons now utilize UEAs in the evaluation of endovascular repair to detect endoleaks without the need of ionizing radiation. Newer applications are emerging in the detection of left atrial appendage thrombi and quantification of myocardial blood flow and volume in transplant patients.

Techniques To Improve Left Atrial Appendage Imaging

The clinical importance of the left atrial appendage (LAA) is increasingly recognized. The assessment of the unique anatomy and function of the LAA is especially important in the setting of atrial fibrillation (AF). AF is the most commonly occurring cardiac arrhythmia, and the association of LAA thrombi and AF has been well established. Transesophageal echocardiography (TEE) is a widely available imaging tool to exclude the potential presence of LAA thrombus prior to cardioversion in patients with AF. Commercially available products containing microbubbles to enhance ultrasound images, termed "ultrasound contrast agents" (UCA) are indicated for use with transthoracic echocardiography to improve cardiac structure and function assessment, but can also be used with TEE as an adjunctive tool to assess the LAA. Integrative multimodality imaging techniques can be used in evaluation of the LAA as indicated in various clinical scenarios including: stroke risk assessment, decision-making prior to cardioversion in AF, placement and assessment percutaneous transcatheter LAA occlusion procedures, and assessment of results of procedural or surgical exclusion of LAA. In this article, various imaging techniques that are available for non-invasive visualization of the LAA will be reviewed along with the clinical importance of assessment of LAA anatomy and function.

A computer-aided diagnostic algorithm improves the accuracy of transesophageal echocardiography for left atrial thrombi: a single-center prospective study

OBJECTIVES

We investigated whether transesophageal echocardiography (TEE) assisted with a computer-aided diagnostic (CAD) algorithm was superior to TEE in diagnosing left atrial (LA)/left atrial appendage (LAA) thrombi in patients with atrial fibrillation (AF) in a single prospective study.

METHODS

Transesophageal echocardiography was performed in patients with AF, and images were reconstructed. Gray level co-occurrence matrix-based features were calculated and then classified using an artificial neural network. The original data and processed images by the CAD system were studied by 5 radiologists independently in a blind manner. The diagnostic performance of each radiologist was evaluated.

RESULTS

One hundred thirty patients with AF were investigated. Thirty-one patients (23.9%) had a diagnosis of LA/LAA thrombi. The mean sensitivity ± SD of TEE for LA/LAA thrombi was 0.933 ± 0.027, which was noticeably improved by CAD (0.955 ± 0.021; P < .05). The specificity of TEE was 0.811 ± 0.055, which was markedly lower than that by TEE plus CAD (0.970 ± 0.009; P < .05). The positive predictive value of TEE was low (0.613 ± 0.073) compared to that of TEE plus CAD (0.908 ± 0.027; P < .001), whereas the negative predictive values were comparable for TEE, CAD, and TEE plus CAD. Diagnosis of an LA/LAA thrombus by TEE plus CAD had a higher accuracy rate (0.966 ± 0.011) than that by TEE (0.840 ± 0.047; P < .01). The mean area under the receiver operating characteristic curve (Az) for TEE was 0.834 ± 0.009 (95% confidence interval [CI], 0.815-0.852), which was markedly lower than the Az for TEE plus CAD (0.932 ± 0.005; 95% CI, 0.921-0.943). The use of CAD significantly improved the Az values for all 5 radiologists (P < .001).

CONCLUSIONS

The CAD algorithm significantly improves the diagnostic accuracy of TEE for LA/LAA thrombi in patients with AF.