Artificial intelligence in detecting left atrial appendage thrombus by transthoracic echocardiography and clinical features: the Left Atrial Thrombus on Transoesophageal Echocardiography (LATTEE) registry.

AIMS: Transoesophageal echocardiography (TOE) is often performed before catheter ablation or cardioversion to rule out the presence of left atrial appendage thrombus (LAT) in patients on chronic oral anticoagulation (OAC), despite associated discomfort. A machine learning model [LAT-artificial intelligence (AI)] was developed to predict the presence of LAT based on clinical and transthoracic echocardiography (TTE) features. METHODS AND RESULTS: Data from a 13-site prospective registry of patients who underwent TOE before cardioversion or catheter ablation were used. LAT-AI was trained to predict LAT using data from 12 sites (n = 2827) and tested externally in patients on chronic OAC from two sites (n = 1284). Areas under the receiver operating characteristic curve (AUC) of LAT-AI were compared with that of left ventricular ejection fraction (LVEF) and CHA2DS2-VASc score. A decision threshold allowing for a 99% negative predictive value was defined in the development cohort. A protocol where TOE in patients on chronic OAC is performed depending on the LAT-AI score was validated in the external cohort. In the external testing cohort, LAT was found in 5.5% of patients. LAT-AI achieved an AUC of 0.85 [95% confidence interval (CI): 0.82-0.89], outperforming LVEF (0.81, 95% CI 0.76-0.86, P < .0001) and CHA2DS2-VASc score (0.69, 95% CI: 0.63-0.7, P < .0001) in the entire external cohort. Based on the proposed protocol, 40% of patients on chronic OAC from the external cohort would safely avoid TOE. CONCLUSION: LAT-AI allows accurate prediction of LAT. A LAT-AI-based protocol could be used to guide the decision to perform TOE despite chronic OAC.

Overcoming barriers for left atrial appendage thrombus: a systematic review of left atrial appendage closure.

BACKGROUND: Approximately 90% of intracardial thrombi originate from the left atrial appendage in non-valvular atrial fibrillation patients. Even with anticoagulant therapy, left atrial appendage thrombus (LAAT) still occurs in 8% of patients. While left atrial appendage closure (LAAC) could be a promising alternative, the current consensus considers LAAT a contraindication to LAAC. However, the feasibility and safety of LAAC in patients with LAAT have yet to be determined. METHODS: This systematic review synthesizes published data to explore the feasibility and safety of LAAC for patients with LAAT. RESULTS: This study included a total of 136 patients with LAATs who underwent successful LAAC. The Amulet Amplatzer device was the most frequently utilized device (48.5%). Among these patients, 77 (56.6%) had absolute contraindications to anticoagulation therapy. Cerebral protection devices were utilized by 47 patients (34.6%). Transesophageal echocardiography (TEE) is the primary imaging technique used during the procedure. Warfarin and novel oral anticoagulants were the main anticoagulant medications used prior to the procedure, while dual antiplatelet therapy was primarily used post-procedure. During a mean follow-up period of 13.2 ± 11.5 months, there was 1 case of fatality, 1 case of stroke, 3 major bleeding events, 3 instances of device-related thrombus, and 8 cases of peri-device leakage. CONCLUSIONS: This review highlights the preliminary effectiveness and safety of the LAAC procedure in patients with persistent LAAT. Future large-scale RCTs with varied LAAT characteristics and LAAC device types are essential for evidence-based decision-making in clinical practice.

Prevalence of left atrial appendage thrombus and spontaneous echo contrast on transesophageal echocardiography in patients scheduled for pulmonary vein isolation.

BACKGROUND: To avoid causing a thromboembolic event in patients undergoing catheter ablation for atrial fibrillation (AF), patients are treated with oral anticoagulants (OAC) prior to the procedure. Despite being on anticoagulants, some patients develop a left atrial appendage thrombus (LAAT). To exclude the presence of LAAT, transesophageal ultrasound (TEE) is performed in all patients prior to the procedure. We hypothesized continuous treatment with anticoagulants would result in a low prevalence of LAAT, in patients with low CHA2DS2-VASc score. METHOD: Medical records of consecutive patients planned to undergo AF ablation at Lund University Hospital during the years 2018-2020 were reviewed retrospectively. Examination protocols from transesophageal and transthoracic echocardiography were examined for LAAT and spontaneous echo contrast (SEC). Patients with LAAT and SEC were compared to patients without using Mann-Whitney U-test and Pearson Chi-squared analysis to test for correlation. RESULTS: Of 553 patients, three patients (0.54%) had LAAT, and 18 (3.25%) had spontaneous contrast (SEC). Patients with LAAT or SEC had a higher CHA2DS2-VASc score, more often presented in AF at TEE and less often had a normal sized left atrium. CONCLUSION: There is a low prevalence of LAAT and SEC in patients with AF scheduled for pulmonary vein isolation. Patients with SEC or LAAT tend to have paroxysmal AF less often and more often presented in AF at admission. No patients with CHA2DS2-VASc 0, paroxysmal AF, normal sized left atrium and sinus rhythm at TEE were found to have LAAT or SEC.

Left atrial appendage structural characteristics predict thrombus formation.

INTRODUCTION: Nonvalvular atrial fibrillation (NVAF) is a highly prevalent arrhythmia where loss of synchronized atrial contraction increases the risk of intracardiac thrombus particularly within the left atrial appendage (LAA). Anticoagulation is the mainstay of stroke prevention based on the CHA2 DS2 -VASc score; however, it does not account for LAA structural characteristics. METHODS: The research comprises a retrospective matched case-control study of 196 subjects with NVAF who underwent transesophageal echo (TEE). The control group, without thrombus (n = 117), was selected from two different groups, both pools had: NVAF and CHA2 DS2 -VASc score ≥ 3. One group underwent screening TEE before Watchman closure device placement from January 2015 to December 2019 (n = 74) the second underwent TEE before cardioversion from February to October 2014 (n = 43). The study group, with thrombus (n = 79), included patients with NVAF, TEE study performed between February 2014 and December 2020, and LAA thrombus. The propensity score method was utilized to determine the matched controls while accounting for confounding from prognostic variables resulting in 61 matched pairs included in the analysis data set. LAA ostial area (OA) (calculated from orthogonal measurements 0°, 90° or 45°, 135°), LAA maximal depth, and peak LAA outflow velocity were measured. RESULTS: Patient characteristics and TEE data were collected and compared using the t test or χ2 analysis. We observed a lower LAA peak exit velocity in the thrombus group as compared to the control group. Additionally, we found that patients in the thrombus group had smaller LAA OA at 0° and 90°, at 45° and 135°, using largest diameter, as well as using aggregate OA, and smaller maximum LAA depth compared to patients in the control group. Candidate conditional logistic regression models for the outcome of the presence of thrombus were evaluated. Statistical results from the best-fitting conditional regression model were calculated showing a significant association between aggregate OA and LAA exit velocity with presence of thrombus. CONCLUSION: Utilizing LAA structural characteristics to predict thrombus formation may help refine current cardioembolic stroke (CES) risk estimation.

Diagnostic and therapeutic pathways for the malignant left atrial appendage: European Heart Rhythm Association physician survey.

AIMS: Patients with atrial fibrillation who despite taking oral anti-coagulant therapy (OAT) suffer a stroke or systemic embolism (SSE) without vascular cause or who develop left atrial appendage (LAA) thrombus (LAAT) should be considered as having malignant LAA. The optimal treatment strategy to reduce SSE risk in such patients is unknown. The aim of the study is to investigate the diagnostic and therapeutic pathways for malignant LAA practiced in European cardiac centres. METHODS AND RESULTS: An 18-item online questionnaire on malignant LAA was disseminated by the European Heart Rhythm Association (EHRA) Scientific Initiatives Committee. A total of 196 physicians participated in the survey. There seems to be high confidence in transoesophageal echocardiography (TEE) imaging, considering LAAT diagnosis. Switching to another direct oral anti-coagulant (DOAC) is the preferred initial step for the treatment of malignant LAA followed by a switch to vitamin K antagonist (VKA), low-molecular-weight heparin, or continued/optimized DOAC dosage, whereas LAA closure is the last option. Left atrial appendage closure is a viable option in patients with embolic stroke despite OAT and no evidence of thrombus at TEE (empty LAA) after comprehensive diagnostic measures to exclude other sources of embolism. CONCLUSION: This EHRA survey provides a snapshot of the contemporary management of patients diagnosed with malignant LAA. Currently, the majority of patients are treated on an outpatient basis with either shifting from VKA to DOAC or from one DOAC to another. Left atrial appendage closure in this population seems to be reserved for patients with higher bleeding risk or complications of malignant LAA, such as stroke.

Associations between neutrophil-lymphocyte ratio and monocyte to high-density lipoprotein ratio with left atrial spontaneous echo contrast or thrombus in patients with non-valvular atrial fibrillation.

BACKGROUND: The importance of inflammation in thrombosis is increasingly appreciated. Neutrophil-lymphocyte ratio (NLR) and monocyte to high-density lipoprotein ratio (MHR) are important indicators of systemic inflammation. This study aimed to investigate the associations between NLR and MHR with left atrial appendage thrombus (LAAT) and spontaneous echo contrast (SEC) in patients with non-valvular atrial fibrillation. METHODS: This retrospective, cross-sectional study enrolled 569 consecutive patients with non-valvular atrial fibrillation. Multivariable logistic regression analysis was used to investigate independent risk factors of LAAT/SEC. Receiver operating characteristic (ROC) curves were used to evaluate the specificity and sensitivity of NLR and MHR in predicting LAAT/SEC. Subgroup and Pearson correlation analyses were used to assess the correlations between NLR and MHR with the CHA2DS2-VASc score. RESULTS: Multivariate logistic regression analysis showed that NLR (OR: 1.49; 95%CI: 1.173-1.892) and MHR (OR: 2.951; 95%CI: 1.045-8.336) were independent risk factors for LAAT/SEC. The area under the ROC curve of NLR (0.639) and MHR (0.626) was similar to that of the CHADS2 score (0.660) and CHA2DS2-VASc score (0.637). Subgroup and Pearson correlation analyses showed significant but very weak associations between NLR (r = 0.139, P < 0.05) and MHR (r = 0.095, P < 0.05) with the CHA2DS2-VASc score. CONCLUSION: Generally, NLR and MHR are independent risk factors for predicting LAAT/SEC in patients with non-valvular atrial fibrillation.

Study on the correlation between false-positive filling defect in LAA CT and LAA structure in patients with atrial fibrillation based on TEE.

OBJECTIVE: This study aims to explore the actual meaning of "false positive filling defect" in left atrial appendage (LAA) computed tomography (CT) in patients with atrial fibrillation (AF), with transesophageal echocardiography (TEE) as the gold standard. METHODS: Patients with AF undergoing cardiac CT angiography and TEE examinations for proposed radiofrequency catheter ablation between October 2020 and October 2021 were selected as the study subjects. Transesophageal echocardiography was taken as the "gold standard," and spontaneous echocardiographic contrast (SEC) and thrombus events were defined as positive events. The CT manifestations were classified into three groups (true positive, false positive, and true negative) to evaluate the differences in left atrium (LA) anterior-posterior diameter (LAAP), LA anterior wall thickness, and LAA orifice long diameter and short diameter, area, and depth between the three groups. RESULTS: (1) There was no statistical difference in LA anterior wall thickness between the three groups (p > .05); there was a statistical difference in LAAP (only) between the true-positive group and the true-negative group (p < .05). (2) There was a statistical difference in LAA orifice long diameter, short diameter, and area between the true-positive group and the true-negative group as well as between the false-positive group and the true-negative group (p < .05). (3) There was a statistical difference in LAA depth between the true-positive group and the false-positive group as well as between the true-positive group and the true-negative group (p < .05). (4) The area under the receiver operator characteristic curve (AUC) of LAA depth affecting the LAA thrombus and SEC was 0.863 (confidence interval = 0.718-1.000), the sensitivity was 77.8%, and the specificity was 90.6% for predicting the occurrence of LAA thrombus and SEC in patients with nonvalvular AF (NVAF) and an LAA depth of ≥50.84 mm. CONCLUSIONS: There was a difference in LAA diameter between the TEE-based CT false-positive group and the other groups. A "CT false positive" is an objectively existing state, and CT might be able to identify the LAA hemodynamic disorder earlier than TEE. Furthermore, a CT + TEE combined application could more accurately evaluate LAA hemodynamics in patients with AF.

Echocardiography in Percutaneous Left Atrial Appendage Occlusion and Related Complications.

Atrial fibrillation (AF) is a devastating disease with a large global prevalence. The left atrial appendage (LAA) is a major source of thrombi in patients with AF. Echocardiography plays an important role in identifying LAA thrombi and has become an invaluable imaging tool in planning for LAA occlusion (LAAO) in patients intolerant to anticoagulation. This review article will discuss the role of echocardiography in selecting patients for LAAO, intraprocedural monitoring, and identifying procedure-related complications.

Left atrial appendage thrombus in acute stroke: diagnostic accuracy of CT angiography compared to transesophageal echocardiography.

OBJECTIVES: To evaluate the value of an extended emergency computed tomography angiography (CTA) including cardiac imaging in patients with acute ischemic stroke for the detection of left atrial appendage (LAA) thrombus compared to transesophageal echocardiography (TEE) as a reference standard. MATERIALS AND METHODS: We conducted a retrospective case-control study of patients with presumed acute ischemic stroke who had undergone non-ECG-gated CTA for the craniocervical vessels with an extended coverage including the heart in the context of emergency stroke evaluation and for whom TEE was available as part of the routine stroke diagnostic. We selected cases with evidence of LAA thrombus in TEE and controls without LAA thrombus in TEE in a 1:3 ratio. Two independent observers analyzed CTA images for presence of LAA thrombus and were blinded to the presence of thrombus in TEE. RESULTS: Twenty-two patients with LAA thrombus in TEE, and 66 patients without LAA thrombus in TEE were included. The detection of LAA thrombus using CTA showed a sensitivity of 63.6%, a specificity of 81.8%, a positive predictive value of 53.9% and a negative predicted value of 87.1%. Interobserver agreement was only moderate (Cohen´s κ = 0.43). CONCLUSIONS: An extended emergency CTA including cardiac imaging can be helpful in early risk stratification in patients with stroke of cardioembolic origin. However, our data show that a standard CTA of craniocervical vessels with extended coverage of the heart is of limited value when compared to TEE, the standard method of detecting LAA thrombi.

A nomogram to predict left atrial appendage thrombus and spontaneous echo contrast in non-valvular atrial fibrillation patients.

BACKGROUND: Non-valvular atrial fibrillation (NVAF) significantly increases the risk of stroke. Although there is availability of prediction models, their ability to predict the risk of stroke in NVAF patients remains suboptimal. Therefore, there is need to improve prediction of high-risk individuals, which is critical for efficient management of patients with NVAF. OBJECTIVE: The objective of our paper is to develop a nomogram for predicting the risk of left atrial appendage thrombus (LAAT) and spontaneous echo contrast (SEC), thereby replacing the risk of stroke in NVAF patients. DESIGN: This was a retrospective cohort study that analyzed clinical data and echocardiographic indices of 387 patients with NVAF from October 2018 to June 2021. Multivariable logistic regression was used to evaluate independent factors that were used to construct the prediction nomogram. ANALYSIS: The discriminative ability and calibration of the nomogram to predict LAAT/SEC were tested using C-statistic and calibration plot. The performance of the nomogram was assessed against the CHA2DS2 score, CHA2DS2-VASc score and ATRIA score using the receiver operating characteristic curve (ROC), decision curve analysis (DCA), integrated discrimination index (IDI) and net reclassification index (NRI). RESULT: Out of the total 387 patients enrolled in this study, 232 had LAAT/SEC. Multivariable analyses demonstrated that N-terminal pro-B-type natriuretic peptide (NT-proBNP), albumin (ALB), LAA ejection fraction (LAAEF) and LAA global peak longitudinal strain (LAA GPLS) were independent predictors of LAAT/SEC. The constructed nomogram had good discriminative (C = 0.886) and calibration (0.876) abilities after bias correction by the C-index. Compared with other models, the decision curve analyses demonstrated that the nomogram had greater net benefits. Besides, the nomogram had significant improvement in predictive performance, sensitivity and reclassification for LAAT/SEC compared with the CHA2DS2 [(c-index: 0.886 vs. 0.576, p < 0.05), (NRI: 0.539, p < 0.05), (IDI: 0.432, p < 0.05)], CHA2DS2-VASc [(c-index: 0.886 vs0.579, p < 0.05), (NRI: 0.513, p < 0.05), (IDI: 0.432, p < 0.05)] or ATRIA [(c-index: 0.886 vs0.583, p < 0.05), (NRI: 0.546, p < 0.05), (IDI: 0.432, p < 0.05)]. CONCLUSION: Taken together, our data demonstrated that the developed nomogram was effective and had potential clinical application in the prediction of LAAT/SEC in patients with NVAF.

Transition from transesophageal echocardiography to cardiac computed tomography for the evaluation of left atrial appendage thrombus prior to atrial fibrillation ablation and incidence of cerebrovascular events during the COVID-19 pandemic.

BACKGROUND: Transesophageal echocardiography (TEE) is variably performed before atrial fibrillation (AF) ablation to evaluate left atrial appendage (LAA) thrombus. We describe our experience with transitioning to the pre-ablation cardiac computed tomography (CT) approach for the assessment of LAA thrombus during the COVID-19 pandemic. METHODS: We studied consecutive patients undergoing AF ablation at our center. The study cohort was divided into pre- versus post-COVID groups. The pre-COVID cohort included ablations performed during the 1 year before the COVID-19 pandemic; pre-ablation TEE was used routinely to evaluate LAA thrombus in high-risk patients. Post-COVID cohort included ablations performed during the 1 year after the COVID-19 pandemic; pre-ablation CT was performed in all patients, with TEE performed only in patients with LAA thrombus by CT imaging. The demographics, clinical history, imaging, and ablation characteristics, and peri-procedural cerebrovascular events (CVEs) were recorded. RESULTS: A total of 637 patients (pre-COVID n = 424, post-COVID n = 213) were studied. The mean age was 65.6 ± 10.1 years in the total cohort, and the majority were men. There was a significant increase in pre-ablation CT imaging from pre- to post-COVID cohort (74.8% vs. 93.9%, p ≤ .01), with a significant reduction in TEEs (34.6% vs. 3.7%, p ≤ .01). One patient in the post-COVID cohort developed CVE following negative pre-ablation CT. However, the incidence of peri-procedural CVE between both cohorts remained statistically unchanged (0% vs. 0.4%, p = .33). CONCLUSION: Implementation of pre-ablation CT-only imaging strategy with selective use of TEE for LAA thrombus evaluation is not associated with increased CVE risk during the COVID-19 pandemic.

Left atrial appendage morphology predicts the formation of left atrial appendage thrombus.

BACKGROUND: Nonchicken wing left atrial appendage (LAA) morphology is associated with higher risk for stroke in patients with atrial fibrillation (AF) than chicken wing (CW) morphology. OBJECTIVE: Assess whether LAA morphology predicts the formation of LAA thrombus independent of age, sex, presenting rhythm, left ventricular ejection fraction (LVEF), or anticoagulant use. METHODS: A cross-sectional analysis was performed on patients prospectively enrolled in the Vanderbilt LAA Registry or presenting for transesophageal echocardiogram (TEE) between January 1, 2015, and November 1, 2017 (n = 306). Two physicians independently reviewed TEEs interpreted as having LAA thrombus. Determination of LAA morphology, ejection velocity, and presence of thrombus (n = 102) were based on 0°, 45°, 90°, and 135° TEE views. The control cohort (n = 204) included consecutive AF patients undergoing TEE without LAA thrombus. RESULTS: LAA morphology in patients with LAA thrombus was: 35% windsock, 47% broccoli, and 12% CW. Windsock (odds ratio [OR], 4.0; 95% confidence interval [CI]: 1.7-9.3, p = .001) and broccoli (OR, 6.6; 95% CI: 2.6-16.6; p < .001) morphology were higher risk for thrombus compared to CW. Female sex predicted higher-odds for LAA thrombus (OR, 2.6; 95% CI: 1.4-4.8; p = .002) as did LAA-EV < 20 cm/s (OR, 11.12; 95% CI: 5.6-22.1). Anticoagulation use (OR, 0.5; 95% CI: 0.3-0.9; p = .03) and higher LVEF (OR, 0.95; 95% CI: 0.93-0.98; p < .001) were associated with lower risk. In patients with a CW morphology who had LAA thrombus, 4 of the 7 had an LAA-EV < 20 cm/s and acute systolic heart failure with LVEF < 30% or active malignancy. In multivariable linear regression analysis controlling for presenting rhythm, anticoagulant use, age, sex, and LVEF, CW morphology appears relatively protective from LAA thrombus (p = .001). CONCLUSION: CW LAA morphology appears relatively protective against the formation of LAA thrombus.

Usefulness of an isoproterenol infusion to differentiate a left atrial appendage thrombus in a patient with nonvalvular atrial fibrillation.

A 78-year-old male with a history of a cardiac embolic stroke due to persistent AF and cerebral bleeding (CHADS2 score 4, HAS-BLED score 4) was referred to our hospital to implant a left atrial appendage (LAA) closure (LAAC) device. A trans esophageal echocardiography was performed and a high echoic lesion that was difficult to differentiate the spontaneous echo contrast or thrombus was found in the LAA cavity. After isoproterenol infusion, a high echoic lesion disappeared and we confirmed that it was not an LAA thrombus. Successful LAAC device implantation was performed without any thromboembolic events.

Prevalence of left atrial thrombus by real time three-dimensional echocardiography in patients undergoing electrical cardioversion of atrial fibrillation: A contemporary cohort study.

BACKGROUND: The prevalence of left atrial thrombi in patients scheduled for electrical cardioversion (ECV) of atrial fibrillation (AF) remains unknown in contemporary real-life practice. METHODS AND RESULTS: Patients scheduled for ECV underwent transesophageal echocardiography (TEE) regardless of AF duration and type of anticoagulant. Of 277 consecutive patients (65% men, mean age 71 ± 10 years, CHA2 DS2 -VASc 3.1 ± 1.4), 92 were on direct oral anticoagulants (DOACs) and 99 on antivitamin K (AVK) oral agents for at least 3 weeks before and 4 after ECV. Eighty-five patients with paroxysmal AF on low-molecular-weight heparin were also considered. Real time three-dimensional TEE detected left atrial appendage (LAA) thrombus in 7% of patients, without significant difference among three groups (P = .334). Anticoagulation was ineffective in eight patients on AVK oral agents, two of them had thrombus. Eight patients assumed incorrectly DOACs, four of them had thrombus. Among the 175 patients on effective anticoagulation, five showed thrombus, three on AVK oral agents, and two on DOACs (P = .716). Effective anticoagulation was associated with reduced risk of thrombosis (OR: 0.16, 95%CI: 0.06-0.45, P = .001). In patients with correct anticoagulation, predictors of thrombus were CHA2 DS2 VASc (for each point of increment OR: 1.97, 95%CI: 1.08-3.61, P = .029), low left ventricular ejection fraction (OR: 0.92, 95%CI: 0.86-0.99, P = .026), and degree of spontaneous echo-contrast (for each point increase OR: 10, 95%CI: 2-39, P < .0001). CONCLUSION: Patients with AF, on effective anticoagulation, had a prevalence of thrombus not negligible regardless of type of anticoagulant. TEE is prudent before ECV and mandatory if unsuccessful anticoagulation is proved or suspected.

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.

Warfarin vs non-vitamin K oral anticoagulants for left atrial appendage thrombus: A meta-analysis.

INTRODUCTION: Novel oral anticoagulants (NOACs) are commonly used for thromboembolic risk reduction and treatment of pulmonary embolism and deep venous thrombosis. However, data regarding their efficacy and safety in comparison to warfarin for left atrial appendage thrombus is limited. METHODS: A comprehensive literature search in PubMed, Google Scholar, and Cochrane Review from inception to 30 October 2019 was performed. Studies reporting clinical outcomes comparing warfarin vs NOACs were included. Two investigators independently extracted the data and individual quality assessment was performed. A meta-analysis was performed using random-effects model to calculate risk ratio (RR) and 95% confidence interval (CI). The analysis was performed using RevMan 5.3. RESULTS: Four studies met inclusion criteria and a total of 322 patients were included of whom 141 were in the NOAC arm and 181 were in the warfarin arm. There was no significant difference in thrombus resolution between the two groups (RR, 1.00; 95% CI [0.77-1.29; P = .98]). There was no significant difference in major bleeding (RR, 1.30; 95% CI [0.14-12.21; P = .82]) or stroke (RR, 0.42; 95% CI [0.09-2.06; P = .29]) between the two groups. CONCLUSION: The results of our meta-analysis show that NOACs are as efficacious and safe as warfarin in the treatment of left atrial appendage thrombus in patients with non-valvular atrial fibrillation.

Management of thrombus formation after electrical isolation of the left atrial appendage in patients with atrial fibrillation.

AIMS: Left atrial appendage (LAA) electrical isolation (LAAEI) in addition to pulmonary vein isolation is an emerging catheter-based therapy to treat symptomatic atrial fibrillation. Previous studies found high incidences of LAA thrombus formation after LAAEI. This study sought to analyse therapeutic strategies aiming at the resolution of LAA thrombi and prevention of thromboembolism. METHODS AND RESULTS: Left atrial appendage electrical isolation was conducted via creation of left atrial linear lesions or cryoballoon ablation. Follow-up including transoesophageal echocardiography was conducted. In patients with LAA thrombus, oral anticoagulation (OAC) was adjusted until thrombus resolution was documented. Percutaneous LAA closure (LAAC) under use of a cerebral protection device was conducted in case of medically refractory LAA thrombi. Left atrial appendage thrombus was documented in 54 of 239 analysed patients who had undergone LAAEI. Thrombus resolution was documented in 39/51 patients (72.2%) with available follow-up after adjustment of OAC. Twenty-nine patients underwent LAAC and 10 patients were kept on OAC after LAAEI. No thromboembolic events or further LAA thrombi were documented after 553 ± 443 days of follow-up in these patients. Persistent LAA thrombi despite adaption of OAC was documented in 12/51 patients. One patient remained on OAC until the end of follow-up, while LAAC with a cerebral protection device was performed in 11 patients in the presence of LAA thrombus without complications. CONCLUSION: Left atrial appendage thrombus formation is common after LAAEI. Adjustment of OAC leads to LAA thrombus resolution in most patients. Left atrial appendage closure in the presence of LAA thrombi might be a feasible option in case of failed medical treatment.

Global peak left atrial longitudinal strain assessed by transthoracic echocardiography is a good predictor of left atrial appendage thrombus in patients in sinus rhythm with heart failure and very low ejection fraction - an observational study.

BACKGROUND: Peak left atrial longitudinal strain (PALS) can help identify left atrial appendage thrombus (LAAT) in patients with atrial fibrillation. Nevertheless, few studies have been performed in patients in sinus rhythm without established indications for anticoagulation but with increased risk of LAAT, such as heart failure (HF) with severe left ventricular systolic dysfunction patients. The primary aim of this study was to identify clinical and transthoracic echocardiography predictors of LAAT in HF patients with very low left ventricular ejection fraction and sinus rhythm. The secondary objective was to analyze frequencies and predictors of a composite clinical endpoint of death or hospitalization for ischemic stroke. METHODS: We included 63 patients with HF, left ventricular ejection fraction < 25%, sinus rhythm at presentation, no history of atrial fibrillation, and without any established indications for anticoagulation. We determined whether clinical and transthoracic echocardiography parameters, including left atrial strain analysis, predicted LAAT. Transesophageal echocardiography was performed in all patients. When LAAT was detected, anticoagulation was recommended. The participants were followed for a median of 28.6 months (range 4-40) to determine the composite endpoint. RESULTS: LAAT was found in 20 (31.7%) patients. Global PALS was the best independent predictor of LAAT in univariate and multivariate logistic regression analyses (Gini coefficient 0.65, area under the receiver-operating characteristic curve 0.83). A global PALS value below 8% was a good discriminator of LAAT presence (odds ratio 30.4, 95% CI 7.2-128, p <  0.001). During follow-up, 18 subjects (28.6%) reached the composite clinical endpoint. CHA2DS2-VASc score, use of angiotensin-converting-enzyme inhibitors or angiotensin receptor blockers, and body surface area were significant predictors for the composite endpoint of death or hospitalization for ischemic stroke in the multivariate regression model. CONCLUSIONS: LAAT was relatively common in our group of HF patients and PALS has shown prognostic potential in LAAT identification. Further research is needed to determine whether initiation of anticoagulation or additional screening supported by PALS measurements will improve clinical outcomes in these patients.

Use of ultrasound enhancing agents in transesophageal echocardiography to improve interpretive confidence of left atrial appendage thrombus.

BACKGROUND: The value of ultrasound enhancing agents (UEA) in patients undergoing transesophageal echocardiography (TEE) for the exclusion of left atrial appendage (LAA) thrombi prior to direct current cardioversion (DCCV) is evolving. METHODS: We retrospectively identified 88 consecutive TEEs, where a commercial UEA was used during LAA interrogation. De-identified non-enhanced (pre-UEA) and enhanced cine loop images (post-UEA) from the same subjects were randomly reviewed by four expert readers in a blinded fashion. RESULTS: In 33% of the cases, UEA use was associated with a statistically insignificant improvement in physician confidence (scale, 0-3) in determining the presence or absence of a LAA thrombus (P = 0.071). In instances where non-enhanced images yielded an uncertain interpretation or when the left atrium contained spontaneous echo contrast (SEC), UEA use was associated with an improvement in interpretive confidence in 49% (P < 0.001) and 41% of the cases (P = 0.001), respectively. Overall, the absolute rate of hypothetical decision to proceed with DCCV rose by 9% with the application of UEA (P = 0.004). In instances where non-enhanced images were interpreted with limited confidence or when SEC was present, there were absolute increases of 16% (P < 0.001) and 21% (P < 0.001) in hypothetical procession to DCCV, respectively. In cases of a combination of limited interpretive confidence and SEC, UEA use was associated with a 29% absolute increase in the rate of procession to DCCV (P < 0.001). CONCLUSIONS: In patients undergoing TEE interrogation of the LAA, the use of UEA is associated with an increase in the level of interpretive confidence and higher rates of theoretical procession to DCCV.

Left Atrial or Left Atrial Appendage Thrombus Resolution After Adjustment of Oral Anticoagulant Treatment.

BACKGROUND: There are few reports about non-vitamin K antagonist oral anticoagulant (NOAC) treatment for resolution of left atrium (LA) or left atrial appendage (LAA) thrombus. LAA thrombus is an important cause of cardiogenic cerebral thromboembolism, and the detection rate increases due to more and more patients receiving catheter ablation. However, the results from NOAC use for LA or LAA thrombus are still unknown in real-world practice. The aim of this study was to discover the resolution of LA or LAA thrombus after anticoagulant treatment in real-world practice. METHOD: From January 2013 to December 2016, a total 864 patients underwent transesophageal echocardiography (TEE), and 41 cases of LA or LAA thrombus were detected in our hospital. Among them, a total of 22 patients underwent follow-up TEE to detect the resolution of LA or LAA thrombus. RESULT: The average age of the study patients was 72.0 ± 11 years old, and 61% were male. The average CHA2DS2-VASc scores were 3.76 ± 2.01 points. A total of 22 patients underwent follow-up TEE, and 19 (86.4%) patients presented LA or LAA thrombus resolution. The average resolution duration was 258.47 ± 218.17 days. One-year all-cause mortality was 4.9%, and the incidence of ischemic stroke was 4.9%. Most physicians favored titration of the dosage of NOAC or warfarin in real-world practice. CONCLUSION: In real-world practice, most physicians favored titration of the dosage of NOAC or warfarin for LA or LAA thrombus. LA or LAA thrombus could exist if the patient received a reduced dose of NOAC. High frequency of LAA or LA thrombi could resolve, and a low incidence of ischemic stroke occurred after adjustment of oral anticoagulant treatment.