Prevalence and predictors of left atrial thrombus in patients with atrial fibrillation: is transesophageal echocardiography necessary before cardioversion?

doi:10.1016/j.carrev.2014.12.009

Cardiovascular Revascularization Medicine

Volume 16, Issue 1, January–February 2015, Pages 12-14

https://doi.org/10.1016/j.carrev.2014.12.009 Get rights and content

Abstract

Background

Systemic embolization threatens patients with atrial fibrillation (AF). The risk is enhanced at the time of cardioversion. Transesophageal echocardiography (TEE) prior to cardioversion to screen for left atrial thrombus (LAT), a marker of high risk for embolization, is recommended for many patients with AF.

Objective

To determine clinical and echocardiographic factors associated with LAT formation in AF.

Methods

Data from 600 consecutive patients with AF undergoing TEE prior to cardioversion for the detection of LAT were analyzed. Clinical, laboratory, and echocardiographic parameters were abstracted from the clinical record.

Results

TEE identified LAT in 70 (11.6%) and dense (LA) spontaneous echo contrast (SEC) in 156 (26%). Baseline characteristics and echocardiographic parameters of patients with or without LAT are compared. A prior myocardial infarction, 21 (29.4 %) vs. 31 (5.8), (p < 0.001); hypertension, 60 (85.7%) vs. 386 (72.8), (p 0.02); CHADS₂ ≥ 2, 56 (80%) vs. 308 (58.1%), (p < 0.001) prevalence was higher in patients with LAT. Patients with LAT had lower ejection fraction 38.2 ± 15.6 vs. 46.2 ± 14.5, (p < 0.001); higher LA diameter 4.98 ± 0.7 vs. 4.52 ± 0.7, (p < 0.001); dense LA SEC 44 (62.8) vs. 112 (21.1), (p < 0.001); and low LA appendage emptying velocity 21.7 ± 12.9 vs. 37.5 ± 19.4, (p < 0.001). Multivariate analysis was done, and it revealed that low LA emptying velocity had the strongest independent association with LAT (HR 0.89 [CI 0.83–0.96], p value < 0.001.

Conclusion

LAT is not an uncommon finding of AF patients prior to cardioversion. The current practice of TEE examination may be justified since neither clinical nor routine 2D echo examinations reliably identify LAT.

Introduction

Atrial fibrillation is one of the most common arrhythmias encountered in clinical practice. AF is associated with increased risk of thrombo-embolic stroke with thrombi most frequently located in the left atrial appendage (LAA). Transesophageal echocardiography (TEE) is considered the gold standard in detecting the left atrial thrombus with 97% sensitivity and 100% specificity [1]. TEE has been used in clinical practice to exclude the presence of left atrial thrombus in patients with recent onset AF that has persisted more than 48 hours or in the setting of subtherapeutic anticoagulation before cardioversion [2]. The present study aimed to determine the incidence of LAA thrombus in patients with AF and the clinical and echocardiographic parameters associated with left atrial thrombus formation.

Section snippets

Methods

The study was approved by the MedStar Health Research Institute Institutional Review Board and is compliant with the Health Insurance Portability and Accountability Act.

Results

Left atrial thrombus is not an uncommon finding as was seen in 11.6% of our patients presenting with atrial fibrillation. The incidence of LAA thrombus based on the CHADS₂ score is presented in Fig. 1.

The clinical characteristics of patients with LAA thrombus compared to patients without LAA thrombus are shown in Table 1. Prior myocardial infarction 21 (29.4 %) vs. 31 (5.8), (p < 0.001); hypertension, 60 (85.7%) vs. 386 (72.8), (p 0.02); CHADS₂ ≥ 2, 56 (80%) vs. 308 (58.1), (p < 0.001) prevalence was

Prevalence of LAA thrombus

Left atrial thrombus was found in 11.6% of our patients, and left atrial dense spontaneous contrast was found in 26%. Valerie J et al. report similar prevalence with left atrial thrombus prevalence of 9.7% and left atrial spontaneous echo contrast prevalence of 44.9%. According to this study, left ventricular ejection fraction of < 40% was the only multivariate predictor of left atrial thrombus formation [3]. The incidence of LAA thrombus is lower in patients with atrial flutter (5.4%) [4].

Clinical predictors associated with LAA thrombus

CHADS₂

Limitations

This study includes those limitations that are inherent to any retrospective study. One of the limitations of the study was that it was a single-center trial. In this study, we did not evaluate TEE findings in conjunction with clinical outcomes.

Conclusion

Left atrial thrombus is not an uncommon finding in patients presenting with atrial fibrillation. It is associated clinically with prior myocardial infarction, and hypertension and echocardiographically with low ejection fraction, enlarged left atrial diameter, and reduced left atrial appendage emptying velocity.

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Cited by (26)

A new risk model of assessing left atrial appendage thrombus in patients with atrial fibrillation – Using multiple clinical and transesophageal echocardiography parameters
2020, International Journal of Cardiology
Citation Excerpt :
However, for some patients with poor echo image quality, it is difficult to distinguish LAA thrombus from pectinate muscles, necessitating an improved risk assessment method to avoid the missed diagnosis of the potential thrombus. As for TEE parameters, LAA peak emptying flow velocity (LAAV) has been proposed as an echocardiographic predictor of LAA thrombus [5,6]. However, there are still controversies about its predictive ability and no uniform standard for its best cut-off value [7,8].
Predicting left atrial appendage thrombus (LAAT) in non-valvular atrial fibrillation (NVAF) patients need more precisely quantified risk models. In this study, we attempted to review the risk markers for LAAT and develop a simple and reliable model for LAAT prediction.
The study included 307 patients with NVAF who were scheduled for transesophageal echocardiography (TEE) to exclude LAA thrombus before synchronized electrical cardioversion or radiofrequency ablation for atrial fibrillation (AF). We analyzed the relationship between echo, clinical parameters and the presence or absence of LAAT.
A total of 33 patients were found having LAAT (10.7%, 33/307). The age, left atrial appendage emptying velocity (LAAEV), left atrial or left atrial appendage spontaneous echocardiographic contrast (SEC), less than moderate to severe mitral regurgitation (≤mild MR), and left atrial enlargement showed association with LAAT. The multivariate logistic regression analysis revealed that LAAEV, SEC and ≤mild MR were independent risk factors of the LAAT. We used LAAEV ≤ 21.5 cm/s, SEC and ≤mild MR to construct a combined predictive model for LAAT in NVAF patients (the area under receiver operator characteristic curve: 0.88; 95% confidence interval: 0.82–0.95, P < 0.0001).
Comprehensive evaluation of LAAEV, SEC, and MR with associated LAAT may help risk stratifying the NVAF patients, especially if the LAA imaging quality was suboptimal for identifying thrombus. These parameters may facilitate the decision-making process at the time of TEE.
A novel risk score for predicting left atrial and left atrial appendage thrombogenic milieu in patients with non-valvular atrial fibrillation
2020, Thrombosis Research
Citation Excerpt :
The CHADS2 and the CHA2DS2-VASc scoring systems have been shown to be good predictors of stroke risk in patients with NVAF [2,4]. However, the effectiveness of these two scoring systems in predicting LA and/or LAATM is controversial [2,5–7]. The aim of our study was to establish a simple risk score to predict LA and/or LAATM in NVAF patients, which can help clinicians in choosing therapy for better outcomes.
Although the CHADS2 and CHA2DS2-VASc scoring systems are commonly used as measures of thromboembolic risk in patients with nonvalvular atrial fibrillation (NVAF), data are inconsistent as to their value in predicting the presence of left atrial (LA) and/or left atrial appendage (LAA) thrombogenic milieu (TM). The present study aimed to establish a novel risk score to assess the risk of LA and/or LAATM in NVAF patients.
This is a retrospective case-control study that included 125 consecutive patients with NVAF plus TM, as evidenced by transesophageal echocardiography (TEE) during a period from1 January 2010 to 1 February 2017. The controls were 1098 NVAF patients without TM during the same period. Risk factors for LA and/or LAATM were identified using univariable analysis and multivariable logistic regression. The risk score model was developed based on 10-fold validation and multiple regression. Risk model performance was evaluated using receiver operating characteristic (ROC) curves. Net reclassification improvement (NRI) was used for the comparison of C-statistics. The AUCs were compared using the Z test.
Among all 1223 NVAF patients, 125 (10.22%) patients had LA and/or LAATM. A score system (0−12) was developed based on the following 6 independent variables identified by 10-fold validation with sequential methods. Different points were assigned for each variable, according to multivariable regression using relative coefficients (coefficient of the index risk factor divided by the lowest coefficient among the 6 risk factors; rounded to closest integer): 1 for blood type A and N-terminal B-type natriuretic peptide (NT-proBNP) ≥864.85 pg/mL; 2 for LAD ≥43.5 mm and age ≥ 73.5 years old; 3 for previous heart failure and previous stroke or TIA. The present risk score system had a sensitivity of 58.3%, specificity of 91.4 and accuracy of 81.6%. The area under the ROC curve (AUC) was 0.832, (95% CI: 0.784–0.881; P < 0.001). The negative predictive value (NPV) was 92% when we set the cut-off point at 4; when the cut-off point was set at 8, the positive predictive value (PPV) was 85.7%. Compared with CHADS2 and CHA2DS2-VASc score, the present novel risk score has better predictive power [net reclassification improvement (NRI) +96.3% and +66.2%, respectively; all P < 0.001].
This study developed a novel risk score to help predicting LA and/or LAATM in NVAF patients, which had higher accuracy than CHADS2 and CHA2DS2-VASc score system.
Assessment and Management of the Left Atrial Appendage Thrombus in Patients With Nonvalvular Atrial Fibrillation
2018, Canadian Journal of Cardiology
Intracardiac thrombi arising in the left atrial appendage (LAA) are the principal cause of stroke in nonvalvular atrial fibrillation (AF). Predicting the presence of LAA thrombi is of vital importance in stratifying patients that would need further LAA imaging prior to cardioversion or AF ablation.
We comprehensively searched PubMed from its inception to November 2017 for randomized controlled trials, cohort and case control studies, as well as for case series on LAA thrombi risk factors, imaging, prevention, and anticoagulation management in atrial fibrillation.
A systematic review of the literature identified 106 articles that investigated the presence of LAA thrombi in AF patients. We classified the articles according to topic and reported on: (1) risk factors; (2) diagnostic imaging modalities; (3) prevention strategies before cardioversion; (4) prevention strategies before AF ablation; and (5) management of detected LAA thrombi.
Integration of clinical, biomarker, and imaging risk factors can improve overall prediction for the presence of LAA thrombi, translating into improved patient selection for imaging. The gold standard for the diagnosis of LAA thrombi remains transesophageal echocardiography, although intracardiac ultrasound, cardiac computed tomography, and cardiovascular magnetic imaging are promising alternative modalities. When LAA thrombi are discovered, the treatment regimen remains variable, although direct oral anticoagulants might have efficacy similar to vitamin K antagonists. Future trials will help further elucidate direct oral anticoagulant use for the treatment of LAA thrombi.
Les thrombus intracardiaques qui se forment dans l’appendice auriculaire gauche sont la principale cause d’AVC dans la fibrillation auriculaire non valvulaire. Il est d’une importance vitale de prédire la présence de thrombus dans l’appendice auriculaire gauche pour stratifier les patients qui pourraient devoir se soumettre à une imagerie médicale de cette région avant une cardioversion ou une ablation pour traiter la fibrillation auriculaire.
Nous avons procédé à une fouille complète dans PubMed, de sa création à novembre 2017, à la recherche d’études contrôlées à répartition aléatoire, d’études de cohortes et d’études cas-témoins, de même que de séries de cas sur les facteurs de risque de thrombus à l’appendice auriculaire gauche, l’imagerie, la prévention et l’anticoagulothérapie dans la fibrillation auriculaire.
Une revue systématique de la littérature a permis de retenir 106 articles portant sur la présence de thrombus dans l’appendice auriculaire gauche chez les patients présentant une fibrillation auriculaire. Nous avons classé ces articles en fonction du sujet et avons fait part : 1) des facteurs de risque; 2) des modalités d’imagerie diagnostique; 3) des méthodes de prévention précédant une cardioversion; 4) des méthodes de prévention précédant une ablation pour traiter la fibrillation auriculaire; et 5) de la prise en charge des thrombus décelés dans l’appendice auriculaire gauche.
L’intégration des facteurs de risque déterminés en clinique, par des biomarqueurs et par l’imagerie peut améliorer la prédiction globale de la présence de thrombus dans l’appendice auriculaire gauche, ce qui permet d’améliorer la sélection des patients pour l’imagerie. La référence standard pour le diagnostic de thrombus dans l’appendice auriculaire gauche demeure l’échocardiographie transœsophagienne, bien que l’échographie intracardiaque, la tomodensitométrie cardiaque et l’imagerie par résonance magnétique cardiovasculaire soient des solutions de rechange prometteuses. Quand des thrombus sont décelés dans l’appendice auriculaire gauche, le schéma thérapeutique demeure variable, bien que des anticoagulants oraux directs puissent avoir une efficacité comparable à celles des antagonistes de la vitamine K. Des essais futurs contribueront à élucider davantage l’utilisation d’un anticoagulant oral direct dans le traitement des thrombus dans l’appendice auriculaire gauche.
ABO blood groups: A risk factor for left atrial and left atrial appendage thrombogenic milieu in patients with non-valvular atrial fibrillation
2017, Thrombosis Research
Citation Excerpt :
However, whether these two scores could predict LATM and/or LAATM thrombus in patients with AF remains controversial [13,34,35]. Malik et al. reported that high CHADS2 score is associated with left atrial thrombus (LAT) [36]. A study by Omer et al. suggested that higher CHA2DS2-VASc score is independently associated with LAT in NVAF patients [13].
Previous studies have identified ABO blood groups as predictors of thromboembolic diseases. In patients with atrial fibrillation (AF), however, potential association between ABO blood groups and the risk of left atrial (LA) and/or left atrial appendage (LAA) thrombogenic milieu (TM) has not been established.
This is a retrospective case-control study that included 125 consecutive patients with non-valvular atrial fibrillation (NVAF) plus TM, as evidenced by transesophageal echocardiography (TEE) during a period from1 January 2010 to 31 December 2016. The controls were selected randomly from 1072 NVAF without TM at a 1:2 ratio. Potential association between ABO blood groups and TM was analyzed using multivariate logistic regression analysis.
The risk of TM was higher in patients with blood group A (33.6% vs. 20.2% in non-A blood groups, P = 0.005). After adjusting for age, sex, oral anticoagulant use, AF type and duration, and relevant functional measures (e.g., NT-pro BNP level, left atrium diameter, and left ventricular ejection fraction), blood group A remained associated with an increased risk of TM (OR = 2.99, 95% CI 1.4–6.388, P = 0.005).
Blood group A is an independent risk factor for TM in NVAF patients.
Incidental Finding of a Right Atrial Appendage Thrombus During Cardiac Surgery
2016, Journal of Cardiothoracic and Vascular Anesthesia
Citation Excerpt :
SEC can be described as an “echogenic swirling blood flow pattern” and constitutes a marker of blood stasis.12 SEC severity correlates with atrial appendage velocities on both sides and has been found to be predictive of the presence of thrombi in a cavity and associated with higher risk of thromboembolism.9,11,13,14 All patients with thrombi do seem to have at least moderate-to-severe SEC, and its occurrence in patients has convinced some clinicians not to proceed to cardioversion.1,15
Left atrial thrombus in a patient without mitral valve disease or atrial fibrillation
2016, Journal of Cardiology Cases
A 54-year-old man presented with back pain. His medical history included hypertension and gout. There was no history of heart disease or arrhythmia. The electrocardiogram showed normal sinus rhythm. Chest computed tomography demonstrated a large calcified tumor (65 mm) in the left atrium (LA). The echocardiogram showed a round hyperechoic mass in the enlarged LA (56 mm) attached to the atrial septum without mitral valve disease. Urgent surgery for excision of the LA mass with the atrial septum and reconstruction by autologous pericardial patch was performed. There was no pathological change in the mitral valve. Due to surgical injury to the conduction system, implantation of a permanent pacemaker was required postoperatively. Histopathological examination revealed calcification, fibrosis, and thrombus formation. LA thrombus without any history of mitral valve disease or atrial fibrillation is rare. Although the mechanism of the present case was unclear, extensive calcified LA myxoma or undiagnosed patent foramen ovale might have been associated with the disease.
<Learning objective: A smooth surface, floating left atrial “ball thrombus” occurs rarely in patients with mitral valve disease or atrial fibrillation. We present a rare case of a giant round left atrial thrombus in a patient without any history of mitral valve disease or atrial fibrillation. Transesophageal echocardiogram showed that the thrombus was round, fixed to the septum, and not floating, and that its surface was calcified. This disease in this patient might have been associated with extensive calcified left atrial myxoma, paroxysmal atrial fibrillation, or undiagnosed patent foramen ovale.>

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ClinicalPrevalence and predictors of left atrial thrombus in patients with atrial fibrillation: is transesophageal echocardiography necessary before cardioversion?

Abstract

Background

Objective

Methods

Results

Conclusion

Introduction

Section snippets

Methods

Results

Prevalence of LAA thrombus

Clinical predictors associated with LAA thrombus

Limitations

Conclusion

J Am Soc Echocardiogr

J Am Soc Echocardiogr

J Am Coll Cardiol

Am J Cardiol

Left atrial thrombus detection with multiplane transesophageal echocardiography: an echocardiographic study with surgical verification

J Heart Valve Dis

ACC/AHA/ECS 2006 guidelines for the management of patients with atrial fibrillation

J Am Coll Cardiol

Clinical
Prevalence and predictors of left atrial thrombus in patients with atrial fibrillation: is transesophageal echocardiography necessary before cardioversion?