Detection of left atrial thrombus during routine diagnostic work-up prior to pulmonary vein isolation for atrial fibrillation: Role of transesophageal echocardiography and multidetector computed tomography

doi:10.1016/j.ijcard.2011.06.124

International Journal of Cardiology

Volume 163, Issue 1, 10 February 2013, Pages 26-33

https://doi.org/10.1016/j.ijcard.2011.06.124 Get rights and content

Abstract

Background

Transesophageal echocardiography (TEE) and multidetector computed tomography (MDCT) are frequently used imaging modalities prior to pulmonary vein isolation (PVI) in order to exclude left atrial (LA) and left atrial appendage (LAA) thrombus and to visualize the anatomy of LA and pulmonary veins. This study aimed to identify predictors of LA/LAA thrombus and to analyze the diagnostic yield of routine pre-procedural TEE and MDCT.

Methods

329 patients with drug-refractory atrial fibrillation (AF) (age 62 ± 10 years; 65% males; 247 paroxysmal AF) referred for pulmonary PVI were included. Prior to the procedure, all patients underwent 64-slice MDCT and TEE, which was used as the gold standard. Risk parameters for thrombus formation were determined, including the CHADS₂ and CHA₂DS₂-VASc scores.

Results

MDCT identified 10 LA/LAA thrombi (3.0%) (8 false positive, 2 true positive), whereas 7 actual thrombi (2.1%) were detected by TEE (5 false negative by MDCT). Sensitivity and specificity of MDCT was 29% and 98%, respectively, with a negative predictive value of 98% and a positive predictive value of 20%. All patients with thrombus were on effective anticoagulation. In multivariate analysis, diabetes mellitus, CHADS₂ score ≥ 3, and CHA₂DS₂-VASc score ≥ 4 were significantly associated with LA/LAA thrombus. No thrombus was seen in patients without risk factors.

Conclusions

In patients presenting for PVI, MDCT does not reliably exclude LA/LAA thrombus. Our study revealed a small but significant prevalence of thrombus despite effective anticoagulation. Diabetes mellitus, CHADS₂ score ≥ 3, and CHA₂DS₂-VASc score ≥ 4 were independent risk predictors of LA/LAA thrombus.

Introduction

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and is associated with increased morbidity and mortality as well as decreased quality of life [1], [2]. Catheter ablation of AF has evolved over the past decade and is currently recommended for symptomatic patients who are refractory to drug therapy [3]. Imaging of the LA and related intrathoracic structures prior to ablation is important for procedural planning [4], [5]. Multidetector computed tomography (MDCT) allows visualization of the entire left atrium (LA), including the left atrial appendage (LAA) and the number and anatomy of the pulmonary veins. In addition, pre-segmented 3D-MDCT data sets might be integrated with advanced electroanatomical mapping systems to assist during the mapping and ablation procedure, and to avoid complications [6].

Thromboembolism, usually originating from the LA and LAA, is a major complication of AF and may result in transitory ischemic attack (TIA) and stroke [1]. The presence of LA/LAA thrombus is a contraindication to catheter ablation of AF since navigation of ablation catheters inside the LA may lead to the dislodgement of in situ thrombi [3]. Accordingly, the 2007 Heart Rhythm Society/European Heart Rhythm Association/European Cardiac Arrhythmia Society consensus statement recommends pre-procedural transesophageal echocardiography (TEE) in order to screen for the presence of thrombus, especially in patients with persistent AF at the time of ablation [3]. Although TEE is still considered the gold standard to exclude LA/LAA thrombus, recent studies have investigated the usefulness and limitations of MDCT in excluding LA/LAA thrombus [7], [8], [9], [10], [11], [12], [13], [14]. However, the results are conflicting and diagnostic accuracy has varied widely between studies. It has further been demonstrated that LA/LAA thrombus may form during effective oral anticoagulation with a vitamin K antagonist such as phenprocoumon [15]. However, the prevalence of LA/LAA thrombus also varies between different reports and recommendations regarding TEE screening in patients with paroxysmal AF or low-risk profile are less clear [3], [16], [17], [18].

The aim of this study was to prospectively analyze the diagnostic yield of routine pre-procedural TEE and cardiac MDCT in patients undergoing pulmonary vein isolation (PVI) and to identify predictors of LA/LAA thrombus formation despite effective anticoagulation.

Section snippets

Patient population

A single-center study was done in 329 patients with drug-refractory, symptomatic paroxysmal or persistent AF scheduled to undergo PVI between October 2007 and April 2010 at the Heart Center of Georg-August-University Göttingen, Germany. All patients were included in a registry and all clinical, imaging and procedural data were prospectively recorded. Paroxysmal AF was defined as self-terminating episodes of AF lasting less than 7 days. Persistent AF was defined as AF sustained > 7 days, and

Patient characteristics

We enrolled 329 consecutive patients, aged 62 ± 10 years; 65% were men. The clinical characteristics of the entire study population are presented in Table 1. Most patients had paroxysmal AF (74%) and were anticoagulated at the time of TEE (78%). According to the CHADS₂ score, the majority of patients fell into low- (CHADS₂ 0 = 22%) or intermediate-risk groups (CHADS₂ 1 = 50%). All patients underwent TEE and MDCT without complications. The actual prevalence of LA/LAA thrombus detected by TEE was 7/329

Main findings

Appropriate anticoagulation does not effectively prevent the formation of LA/LAA thrombus. In our patient population, LA/LAA thrombus was present in 2.1% of patients immediately prior to PVI. We found CHADS₂ score ≥ 3, CHA₂DS₂-VASc scores ≥ 4, and diabetes mellitus to be predictors of the presence of LA/LAA thrombus. There were no cases of LA/LAA thrombus in patients with CHADS₂ or CHA₂DS₂-VASc scores scores < 2. Compared to the gold standard of TEE, 64-slice MDCT was far less reliable in

Conclusion

Seven of 329 (2.1%) patients with AF undergoing TEE prior to PVI had LA/LAA thrombus despite effective anticoagulation. In comparison with TEE, 64-slice MDCT does not reliably exclude LA/LAA thrombus and one cannot confidently perform AF ablation in patients with thrombus negative MDCT scans despite a relatively strong negative predictability. CHADS₂ score ≥ 3, CHA₂DS₂-VASc score ≥ 4, and diabetes mellitus were independent predictors for the presence of thrombus. Other factors, specifically LA

Acknowledgments

The authors of this manuscript have certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology.

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Cerebral thromboembolism is a potentially devastating complication of atrial fibrillation (AF) and atrial flutter (AFl). The use of transesophageal echocardiogram (TEE) before electrophysiological procedures in anticoagulated patients is variable. Our objective was to determine the incidence and identify predictors of intracardiac left atrial appendage (LAA) thrombus on TEE in patients with AF/AFl before electrical cardioversion or ablation.
We reviewed TEEs of 401 patients undergoing an electrical cardioversion, AF, or AFl ablation from April 2013 to September 2015 at the McGill University Health Center. Clinical and echocardiographic variables were collected at the time of the TEE and follow-up visits. Multivariate logistic regression was used to determine predictors of LAA thrombus.
Of 401 patients, 11.2% had LAA thrombus on TEE. The majority (87%) of patients were anticoagulated for at least 3 weeks before the TEE. The incidence of LAA thrombus was 21% (23/110) in patients taking warfarin vs 6.4% (15/236) in patients taking direct oral anticoagulants. Multivariate analysis identified prior stroke (odds ratio [OR], 2.7; 95% confidence interval [CI], 1.1-6.9) and heart failure (OR, 2.2; 95% CI, 1.0-4.7) as predictors of thrombus, whereas direct oral anticoagulant use (OR, 0.4; 95% CI, 0.2-0.8) was associated with reduced odds of thrombus.
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La thromboembolie cérébrale est une complication potentiellement dévastatrice de la fibrillation auriculaire (FA) et du flutter auriculaire. L’utilisation de l’échocardiographie transœsophagienne (ETO) avant les interventions en électrophysiologie chez les patients anticoagulés est variable. Notre objectif était de déterminer la fréquence et les prédicteurs des thrombi intracardiaques dans l’appendice auriculaire gauche (AAG) à l’ETO chez les patients atteints de FA ou de flutter auriculaire avant de procéder à une cardioversion électrique ou à une ablation.
Nous avons passé en revue les ETO de 401 patients qui avaient subi une cardioversion électrique, ou une ablation de la FA ou du flutter auriculaire entre avril 2013 et septembre 2015 au Centre universitaire de santé McGill. Nous avons recueilli les variables cliniques et échocardiographiques au moment de l’ETO et des visites de suivi. Nous avons utilisé la régression logistique multivariée pour déterminer les prédicteurs de thrombus dans l’AAG.
Parmi les 401 patients, 11,2 % avaient un thrombus dans l’AAG à l’ETO. La majorité (87 %) des patients étaient anticoagulés au moins 3 semaines avant l’ETO. La fréquence des thrombus dans l’AAG était de 21 % (23/110) chez les patients qui prenaient de la warfarine vs 6,4 % (15/236) chez les patients qui prenaient des anticoagulants oraux directs. L’analyse multivariée a permis d’établir que l’accident vasculaire cérébral (AVC) antérieur (ratio d’incidence approché [RIA], 2,7; intervalle de confiance [IC] à 95 %, 1,1-6,9) et l’insuffisance cardiaque (RIA, 2,2; IC à 95 %, 1,0-4,7) étaient des prédicteurs de thrombus, alors que l’utilisation d’anticoagulants oraux directs (RIA, 0,4; IC à 95 %, 0,2-0,8) était associée une probabilité moindre de thrombus.
Une proportion importante de patients qui avaient subi l’ETO avant la cardioversion, ou l’ablation de la FA ou du flutter auriculaire avaient un thrombus dans l’AAG en dépit de l’anticoagulation avant l’intervention. Les patients exposés à un risque accru de thrombus dans l’AAG (insuffisance cardiaque et AVC antérieur) peuvent bénéficier de l’ETO avant la cardioversion, ou l’ablation de la FA ou du flutter auriculaire.

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^☆: There are no conflicts of interest.

¹: Both authors contributed equally to this work.

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Detection of left atrial thrombus during routine diagnostic work-up prior to pulmonary vein isolation for atrial fibrillation: Role of transesophageal echocardiography and multidetector computed tomography☆

Abstract

Background

Methods

Results

Conclusions

Introduction

Section snippets

Patient population

Patient characteristics

Main findings

Conclusion

Acknowledgments

Heart Rhythm

Am J Cardiol

Am J Cardiol

Am Heart J

Heart Rhythm

J Am Coll Cardiol Img

Chest

J Am Coll Cardiol

J Am Soc Echocardiogr

J Am Soc Echocardiogr

J Am Coll Cardiol

Am J Cardiol

J Am Coll Cardiol

Circulation

Impact of atrial fibrillation on the risk of death: the Framingham Heart Study

Circulation

Imaging of pulmonary veins during catheter ablation for atrial fibrillation: the role of multi-slice computed tomography

Europace

Extra cardiac findings by 64-multidetector computed tomography in patients with symptomatic atrial fibrillation prior to pulmonal vein isolation

Int J Cardiovasc Imaging

Initial experience in the use of integrated electroanatomic mapping with three-dimensional MR/CT images to guide catheter ablation of atrial fibrillation

J Cardiovasc Electrophysiol

Accuracy of transesophageal echocardiography for identifying left atrial thrombi. A prospective, intraoperative study

Ann Intern Med

Diagnostic accuracy of arterial phase 64-slice multidetector CT angiography for left atrial appendage thrombus in patients undergoing atrial fibrillation ablation

J Cardiovasc Electrophysiol

Comparison of contrast enhanced 64-slice computed tomography and transesophageal echocardiography in detection of left atrial thrombus in patients with atrial fibrillation

J Interv Card Electrophysiol