A new risk model of assessing left atrial appendage thrombus in patients with atrial fibrillation – Using multiple clinical and transesophageal echocardiography parameters
Introduction
It has been estimated that nearly 2.3 million Americans have non-valvular atrial fibrillation (NVAF) [1]. Atrial fibrillation (AF) is related to the increased risk of thromboembolic stroke with thrombus most likely located in the left atrial appendage (LAA) [2]. Transesophageal echocardiography (TEE) is regarded as the gold standard in detecting the LA thrombus with 97% sensitivity and almost 100% specificity [3]. Therefore, TEE has been used routinely to exclude the presence of LA thrombus in patients with recent-onset AF that had lasted >48 h or in the setting of sub-therapeutic anticoagulation before cardioversion [4]. 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]. Several studies have attempted to set up a novel method to predict the presence or absence of LAA thrombus using clinical and/or TEE parameters [9,10]. But in current practice, no commonly accepted standard has been applied for clinical use due to the complex nature of the available data. In this study, we aimed to develop a simpler and reliable model that might improve the prediction of the presence of LAA thrombus based on clinical factors and TEE parameters. This model may help with prompt decision-making in managing the cardioversion protocols of patients with NVAF.
Section snippets
Study design and patient population
This single-center retrospective study included 405 consecutive patients with NVAF undergoing TEE from July 2013 to June 2014 for the detection of LAA thrombus before cardioversion or radiofrequency ablation for atrial fibrillation. The cardiac rhythm at the time of TEE was 100% in atrial fibrillation. We did not include patients with chronic atrial fibrillation. Ninety-eight patients had no measured LAA velocity or inadequate echocardiographic view and therefore were excluded from the study.
Baseline clinical characteristics
Baseline patient characteristics, comorbidities, and medication at the time of TEE are shown in Table 1. The mean age of all NVAF patients was 67.1 years, and 73.6% of the patients were male. Among the 307 NVAF patients, thrombus within the LAA was identified by TEE in 33 (10.7%). Compared with the non-LAAT group, the LAAT group had more elderly patients, SEC and LA enlargement. LAA velocity and the frequency of significant MR were lower in patients with LAAT than in non-LAAT group. All the
Discussion
We showed following results in non-valvular atrial fibrillation (NVAF) cohort: patients with LAA thrombus had significantly lower LAA emptying velocities, more frequent spontaneous echo contrast (SEC), ≤mild MR, LA enlargement and advanced age; LAA emptying velocity ≤21.5 cm/s, SEC and ≤mild MR were independent predictors of LAA thrombus (LAAT); The capacity for predicting LAAT of combining these three factors above is stronger than using any one single factor in NVAF patients prior to
Conclusion
Our study adds to the LAAT risk stratification capability and attempts to aid in decision-making process for LAAT in patients with NVAF. Further research utilizing this method with more clinical and imaging data may help design an intelligent risk assessment system and verify patients' outcomes in the real-world clinical setting.
CRediT authorship contribution statement
Lu Chen: Methodology, Formal analysis, Data curation, Writing - original draft. Ashley Zinda: Methodology, Investigation. Nicholas Rossi: Methodology, Investigation. Xiu-Jie Han: Formal analysis, Data curation. Steve Sprankle: Methodology, Investigation. Renee Bullock-Palmer: Methodology, Investigation. Denise Zingrone: Methodology, Investigation. Mark Moshiyakov: Methodology, Investigation. Justin Szawlewicz: Methodology, Investigation. Allen Mogtader: Methodology, Investigation. David Hsi:
Declaration of competing interest
No conflict of interest relevant to this article.
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