Left Atrial Appendage Thrombus Research Articles

Manual Chest PRESSURE During DirectCurrent Cardioversion for AtrialFibrillation: A Randomized Control Trial (PRESSURE-AF).

Direct current cardioversion is frequently used to return patients with atrial fibrillation (AF) to sinus rhythm. Chest pressure during cardioversion may improve the efficacy of cardioversion through decreasing transthoracic impedance and increasing cardiac energy delivery. This study aimed to assess the efficacy and safety of upfront chest pressure during direct current cardioversion for AF with anterior-posterior pad positioning. This was a multicenter, investigator-initiated, double-blinded, randomized clinical trial. Recruitment occurred from 2021 to 2023. Follow-up was until hospital discharge. Recruitment occurred across 3 centers in New South Wales, Australia. Inclusion criteria were age≥18 years, referred for cardioversion for AF, and anticoagulation for 3weeks or transesophageal echocardiography excluding left atrial appendage thrombus. Exclusion criteria were other arrhythmias requiring cardioversion, such as atrial flutter and atrial tachycardia. The intervention arm received chest pressure during cardioversion from the first shock. The primary efficacy outcome was total joules required per patient encounter. Secondary efficacy outcomes included first shock success, transthoracic impedance, cardioversion success, and sinus rhythm at 30minutes post cardioversion. A total of 311 patients were randomized, 153 to control and 158 to intervention. There was no difference in total joules applied per encounter in the control arm vs intervention arm (355.0 ± 301J vs 413.8 ± 347 J; P=0.19). There was no difference in first shock success, total shocks provided, average impedance, and cardioversion success. This study does not support the routine application of chest pressure for direct current cardioversion in atrial fibrillation (PRESSURE-AF [Investigating the Efficacy of Chest Pressure for Direct Current Cardioversion in Atrial Fibrillation: A Randomized Controlled Trial]; ACTRN12620001028998).

An Uncommon Cause of Syncope and Left Atrial Appendage Thrombus: Speech-Induced Atrial Tachycardia

An 83-year-old, previously healthy woman experienced frequent episodes of syncope following conversations. Speech-induced atrial tachycardia complicated by left atrial appendage thrombus was diagnosed as a potential etiology. She was successfully treated via catheter ablation. This is the first case report suggesting an association between arrhythmia, syncope, and atrial thrombus formation.

Relationship of inflammatory indices with left atrial appendage thrombus or spontaneous echo contrast in patients with atrial fibrillation.

Inflammatory indices derived from complete blood tests have been reported to be associated with poor outcomes in patients with atrial fibrillation (AF). The data about the relationship between inflammatory indices and left atrial appendage thrombus (LAAT) or dense spontaneous echo contrast (SEC) are limited. To explore the value of inflammatory indices for predicting the presence of LAAT or dense SEC in nonvalvular AF patients. A total of 406 patients with nonvalvular AF who underwent transesophageal echocardiography were included and divided into two groups based on the presence (study group) or absence (control group) of LAAT or dense SEC. Inflammatory indices, including the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR), were calculated from complete blood analysis. The associations of inflammatory indices with LAAT/dense SEC were analyzed using logistic regression. LAAT and dense SEC were detected in 11 (2.7%) and 42 (10.3%) patients, respectively. The PLR only showed an association with LAAT/dense SEC in the univariate model. Elevated NLR (odds ratio [OR] = 1.48, 95% confidence interval [CI]: 1.11-1.98, P = 0.007) and reduced LMR (OR = 0.59, 95%CI: 0.41-0.83, P = 0.003) were found to be independent risk factors for the presence of LAAT/dense SEC. The areas under the NLR and LMR curves for predicting LAAT/dense SEC were 0.73 (95%CI: 0.66-0.80, P < 0.001) and 0.73 (95%CI: 0.65-0.81, P < 0.001), respectively, while the cutoff values were 2.8 (sensitivity: 69.8%; specificity: 64.0%) and 2.4 (sensitivity: 71.7%; specificity: 60.6%), respectively. Increased NLR and decreased LMR may predict LAAT/dense SEC in patients with nonvalvular AF.

Intracardiac Echocardiography-Applications in the Electrophysiology and the Cardiac Catheterization Labs.

Background. Intracardiac echocardiography (ICE) is routinely used in cardiac electrophysiology and catheterization labs. It plays a vital role in understanding cardiac anatomy, procedural planning, and early identification of complications. In this review, we describe the utility of ICE for procedures in the electrophysiology lab, including atrial fibrillation ablation, left atrial appendage occlusion device implantation, and cardiac implantable electronic device (CIED) extraction. Intracardiac echocardiography also helps in the identification of complications such as pericardial effusion, pulmonary vein stenosis, and left atrial appendage thrombus. Compared with traditional echocardiographic modalities such as transesophageal echocardiogram (TEE), ICE has equivalent image quality, requires less sedation, and possesses no risk of esophageal injury. The disadvantages of ICE include a learning curve and necessity for central vascular access.

Paradoxical embolic stroke during catheter-directed thrombolytics in a patient with massive pulmonary embolism

Abstract Paradoxical embolism represents a critical and potentially fatal complication that can be associated with pulmonary embolism (PE). This case details a unique case of massive PE, further complicated by embolic stroke occurring during catheter-directed thrombolytic therapy. There was no evidence of thrombosis during the initial evaluation with lower extremity Doppler ultrasound, abdominal computed tomography scan, and transthoracic echocardiography. Differentials for the source of the emboli include unrecognized left atrial appendage thrombus, pulmonary arteriovenous malformations, and a patent left foramen ovale. Our findings highlight the complexities and treatment challenges of massive PE.

Predictors of left atrial appendage thrombus in atrial fibrillation patients undergoing cardioversion.

Atrial fibrillation and atrial flutter represent the most prevalent clinically significant cardiac arrhythmias. While the CHA2DS2-VASc score is commonly used to inform anticoagulation therapy decisions for patients with these conditions, its predictive power is limited. Therefore, we sought to improve risk prediction for left atrial appendage thrombus (LAAT), a known risk factor for stroke in these patients. We developed and validated an explainable machine learning model using the eXtreme Gradient Boosting algorithm with 5 × 5 nested cross-validation. The primary outcome was to predict the probability of LAAT in patients with atrial fibrillation and atrial flutter who underwent transesophageal echocardiogram prior to cardioversion. Our algorithm used 37 demographic, comorbid, and transthoracic echocardiographic variables. A total of 795 patients were included in our analysis. LAAT was present in 11.3% of the patients. The average age of patients was 63.3 years and 34.7% were women. Patients with LAAT had significantly lower left ventricular ejection fraction (29.9% vs 43.5%; p < 0.001), lower E' lateral velocity (5.7cm vs. 7.9cm; p < 0.001) and higher E/A ratio (2.6 vs 1.8; p = 0.002). Our machine learning model achieved a high AUC of 0.79, with a high specificity of 0.82, and modest sensitivity of 0.57. Left ventricular ejection fraction was the most important variable in predicting LAAT. Patients were split into 10 buckets based on the percentile of their predicted probability of having thrombus. The lower the percentile (e.g., 10%), the lower the probability of having thrombus. Using a cutoff point of 0.16 which includes 10.0% of the patients, we can rule out thrombus with 100% confidence. Using machine learning, we refined the predictive power of predicting LAAT and explained the model. These results show promise in providing better guidance for anticoagulation therapy and cardioversion in AF and AFL patients.

Influence of Meteorological Parameters on the Prevalence of TEE Detected Left Atrial Appendage Thrombi.

(1) Background: Meteorological factors seem to exert various effects on human health, influencing the occurrence of diseases such as thromboembolic events and strokes. Low atmospheric pressure in summer may be associated with an increased likelihood of ischemic stroke. The aim of this study was to investigate the potential impact of meteorological conditions on left atrial appendage (LAA) thrombus formation. (2) Methods: A total of 131 patients were included, diagnosed with a first instance of thrombus via 3D transesophageal echocardiography (TEE) between February 2009 and February 2019. Months with frequent thrombus diagnoses of at least 10 thrombi per month were categorized as frequent months (F-months), while months with fewer than 10 thrombus diagnoses per month were labelled as non-frequent months (N-months). The analysis focused on differences in meteorological parameters in two-week and four-week periods before the diagnosis. (3) Results: F-months were predominantly observed in spring and summer (April, May, June, and July), as well as in February and November. During F-months, a higher absolute temperature difference, lower relative humidity, longer daily sunshine duration, and greater wind speed maximum were observed in the two- and four-week periods rather than for N-months. In the two-week period, average temperatures, equivalent temperatures, and temperature maxima were also significantly higher during F-months than N-months. (4) Conclusion: Thrombi in the left atrial appendage are more prevalent during periods characterized by high absolute temperature differences, low relative humidity, and long daily sunshine duration.

Biomarcadores proteómicos para la predicción no invasiva de trombos en la orejuela izquierda de pacientes con fibrilación auricular

Introduction and objectives: The CHA2DS2-VASc score, used to assess the risk of left atrial appendage thrombus (LAAT) formation in patients with atrial fibrillation (AF), has limited predictive value. Moreover, transesophageal echocardiography imaging, the gold standard diagnostic method to identify thrombi, is semi-invasive. Consequently, there is a need for alternative and noninvasive diagnostic methods for LAAT risk assessment.Methods: Deep proteomic analysis was conducted in plasma samples from 8 patients with nonvalvular AF, divided into thrombus and control groups (4 patients in each group) based on the presence or absence of LAAT. Biomarkers associated with LAAT were validated using an enzyme-linked immunosorbent assay in a cohort of 179 patients with available clinical, transthoracic, and transesophageal echocardiography data. Predictive models were developed to assess the improvement in LAAT identification.Results: The LAAT group had higher CHA2DS2-VASc scores, larger LA diameter, and lower LAA flow velocities. Deep proteomic analysis identified 30 differentially expressed proteins, including myosin light chain 4, prenylcysteine oxidase 1 (PCYOX1), and decorin as potential diagnostic biomarkers of LAAT. The model showed that PCYOX1 and decorin provided an area under the curve (AUC) of 0.970 for LAAT prediction compared with 0.672 in a model including the CHA2DS2-VASc score and LAA cauliflower morphology. The incremental value of proteomic biomarkers for LAAT in patients with nonvalvular AF was further confirmed with the net reclassification improvement and integrated discrimination improvement indices.Conclusions: Protein levels of PCYOX1 and decorin improve the predictive performance for LAAT in patients with nonvalvular AF.

Left atrial appendage thrombus is associated with a higher fractal dimension in patients with atrial fibrillation

PurposeTo assess the anatomical complexity of the left atrial appendage (LAA) using fractal dimension (FD) based on cardiac computed tomography angiography (CTA) and the association between LAA FD and LAA thrombosis. Materials and methodsPatients with atrial fibrillation (AF) who underwent both cardiac CTA and transesophageal echocardiography (TEE) between December 2018 and December 2022 were retrospectively analyzed. Patients were categorized into normal (n = 925), circulatory stasis (n = 82), and thrombus groups (n = 76) based on TEE results and propensity score matching (PSM) was performed for subsequent analysis. FD was calculated to quantify the morphological heterogeneity of LAA. Independent risk factors for thrombus were screened using logistic regression. The diagnostic performance of FD and CHA2DS2-VaSc score for predicting thrombus was evaluated using the area under the receiver operating characteristics curve (AUC). ResultsLAA FD was higher in the thrombus group (1.61 [1.49, 1.70], P < 0.001) than in the circulatory stasis (1.33 [1.18, 1.47]) and normal groups (1.30 [1.18, 1.42]) both before and after PSM. LAA FD was also an independent risk factor in the thrombus (OR [odds ratio] = 570,861.15 compared to normal, 41,122.87 compared to circulatory stasis; all P < 0.001) and circulatory stasis group (OR = 98.87, P = 0.001) after PSM. The diagnostic performance of LAA FD was significantly better than the CHA2DS2-VaSc score in identifying thrombus. ConclusionsPatients with high LAA FD are more likely to develop LAA thrombus, and the use of FD provides an effective method for assessing the risk of thrombosis in AF patients, thereby guiding individualized clinical treatment.

Correlation between Anterior Mitral Annular Plane Systolic Excursion and Left Atrial Appendage Stasis in Patients with Nonvalvular Atrial Fibrillation.

Atrial fibrillation (AF) can lead to a decline in left atrial appendage (LAA) function, potentially increasing the likelihood of LAA thrombus (LAAT) and spontaneous echo contrast (SEC). Measuring LAA flow velocity through transesophageal echocardiography (TEE) is currently the primary method for evaluating LAA function. This study aims to explore the potential correlation between anterior mitral annular plane systolic excursion (aMAPSE) and LAA stasis in patients with non-valvular atrial fibrillation (NVAF). A total of 465 patients with NVAF were enrolled between October 2018 and November 2021. Transthoracic echocardiography (TTE) and TEE were performed before scheduled electrical cardioversion. Propensity score matching (PSM) was used to balance confounders between the groups with and without LAAT/dense SEC. Patients in the LAAT/dense SEC group showed increased left atrial (LA) diameter, LAA area, alongside reduced left ventricular ejection fraction (LVEF), LAA velocity, conjunction thickening ratio, aMAPSE, and LAA fraction area change (FAC) compared to those in the non-LAAT/dense SEC group. Multivariate logistic regression analysis identified aMAPSE and LAA FAC as independent predictors for LAAT/dense SEC. Specifically, an aMAPSE of 6.76 mm and an LAA FAC of 29.65% predicted LAAT/dense SEC with high diagnostic accuracy, demonstrated by an area under the curve (AUC) of 0.81 (sensitivity 0.81, specificity 0.80) for aMAPSE, and an AUC of 0.80 (sensitivity 0.70, specificity 0.84) for LAA FAC. Both aMAPSE and LAA FAC independently correlated with and accurately predict LAAT/dense SEC. Incorporating aMAPSE into routine TEE evaluations for LAA function alongside LAA flow velocity is recommended.

Assessment of Coagulation Factors in Patients with Severe Rheumatic Mitral Stenosis in Sinus Rhythm with Left Atrial Appendage Inactivity

BackgroundPatients with severe mitral stenosis (MS) in normal sinus rhythm (NSR), presenting with left atrial appendage (LAA) inactivity and associated left atrial spontaneous echo contrast (LASEC) are prone to left atrium (LA) or LAA thrombus formation. But unlike for atrial fibrillation, oral anticoagulants are not commonly prescribed for this patient subset. This study aimed to compare the levels of procoagulants and fibrinogen in both local (LA) and systemic contexts between patients with severe MS in NSR vs those in healthy control subjects. MethodsThe study involved 35 patients with severe MS in NSR with LAA inactivity and LASEC who were eligible for balloon mitral valvuloplasty vs 35 healthy controls. All patients underwent transthoracic and transesophageal echocardiography to assess MS severity, LAA activity, and LASEC grade, and had blood samples analyzed for procoagulant levels. ResultsResults showed comparable baseline characteristics between groups, with most patients in the New York Heart Association II or III functional classes, and with varying LASEC grades. Patients exhibited significantly higher levels of prothrombin fragment 1 + 2 [patient vs control, 9017 pg/mL (6228.0-10,963.5) vs 1790 pg/mL (842.3-2712), P < 0.0001], thrombin-antithrombin III [patient vs control, 39 ng/mL (5.45-74.85) vs 2.80 ng/mL (1.6-6.5), P < 0.0001], plasminogen activator inhibitor-1 (patients vs controls, 26.09 ± 8.18 ng/mL vs 8.05 ± 3.53 ng/mL, P < 0.0001), and fibrinogen (3.48 ± 0.89 g/L vs 3.01 ± 0.53 g/L, P = 0.029) in the LA of patients, compared to those in control subjects. Systemic procoagulant levels also were elevated in patients, but D-dimer levels were similar between the 2 groups. ConclusionsThe findings suggest a hypercoagulable state in patients, similar to that in patients with atrial fibrillation. The study advocates for consideration of use of oral anticoagulants in these patients until LA and LAA function improves, to mitigate thrombus formation.

Left atrial appendage thrombus in patients with atrial fibrillation who underwent oral anticoagulation.

Electric cardioversion of atrial fibrillation (AF) is associated with an increased risk of embolism, with embolic material existing in the heart cavities. The initiation of oral anticoagulation therapy reduces the risk of thromboembolic events. The aims of this study were to evaluate the prevalence of left atrial appendage (LAA) thrombi in non-valvular AF, to compare vitamin K antagonists (VKAs) and non-vitamin K oral anticoagulants (NOACs) with respect to thrombus prevalence, and to evaluate the rate of LAA thrombus persistence on repeat transesophageal echocardiography (TEE) after treatment change. We enrolled 160 consecutive AF patients who presented with an AF duration > 48 h and had undergone TEE before cardioversion. Left atrial appendage thrombus was observed in 12 (7.5%) patients, and spontaneous echo contrast 4 was observed in 19 (11.8%) patients; the incidence was similar between the NOAC and VKA groups (8.9% vs. 3.6% and 12.4% vs. 18.5 %, respectively). Among patients on NOAC, thrombus prevalence was detected in 8.4% of users of rivaroxaban, 8% of users of dabigatran, and 12.5% of users of apixaban. The LAA thrombus developed in 7.5% of patients despite anticoagulation therapy, demonstrating similar prevalence rates among patients either on NOAC or VKA. Lower mean LAA flow velocity and a history of vascular disease were independent predictors of embolic material in the LAA. It seems that in the case of embolic materials in LAA under NOAC treatment, switching to VKA provides additional clinical benefit to the patients.

Prothrombotic plasma fibrin clot phenotype is associated with spontaneous echo contrast in atrial fibrillation: The role of protein carbonylation

IntroductionSpontaneous echo contrast (SEC) and left atrial appendage thrombus (LAAT) increase the risk of stroke and its severity in patients with atrial fibrillation (AF). Formation of denser fibrin networks and impaired fibrinolysis are associated with stroke risk in AF. This study investigated whether the prothrombotic fibrin clot phenotype characterizes patients with SEC/LAAT. MethodsWe studied 139 anticoagulated patients with AF (median age, 70 years), who underwent transesophageal echocardiography (TEE). SEC and LAAT were recorded. We assessed plasma fibrin clot properties, i.e. permeability (Ks) and clot lysis time (CLT), von Willebrand Factor (vWF) antigen, endogenous thrombin potential (ETP), proteins involved in thrombosis and fibrinolysis, as well as plasma carbonylated protein content (PC). ResultsSEC/LAAT was identified in 36 subjects (25.9 %) and was associated with heart failure (HF), AF duration, higher CHA2DS2VASc score, N-terminal prohormone of brain natriuretic peptide, and growth differentiation factor 15. Patients with SEC/LAAT had lower Ks (−15 %) and prolonged CLT (+19 %), along with higher fibrinogen (+24 %), ETP (+3 %), and plasminogen activator inhibitor-1 antigen (+16 %) compared with the remainder. Thrombin-activatable fibrinolysis inhibitor antigen, plasminogen, α2 − antiplasmin, and tissue plasminogen activator antigen were similar between the two groups. PC content was 50 % higher in SEC/LAAT and correlated with Ks (r = −0.47, p < 0.001) and CLT (r = 0.40, p < 0.001). On multivariate analysis, Ks, CLT, and PC levels, along with HF, remained independently associated with SEC/LAAT. ConclusionsWe demonstrated a formation of denser and poorly lysable fibrin networks in AF patients with SEC/LAAT despite anticoagulation. We suggest that this phenomenon is in part related to enhanced oxidative stress.

Case report: 3 ways to mitigate the risk of embolization during left atrial appendage closure in a patient with a massive and proximal left atrial appendage thrombus

Abstract Background Left atrial appendage (LAA) thrombus is a contraindication for LAA closure (LAAC). However, in selected cases, oral anticoagulants are strictly contraindicated because of a history of life-threatening bleeding, and LAAC remains the only possible therapy to avoid systemic and especially cerebral embolization. Case summary We report a case of LAAC despite a massive proximal thrombus in a patient who had an absolute contraindication to anticoagulant therapy, with thorough pre-planning using CT-scan, device modeling and thrombus trapping techniques to reduce the risk of systemic embolic events and perform LAAC safely. Discussion Although LAAC remains at high risk in this setting, the use of cautious techniques and tools, from pre-procedure planning to systemic embolization prevention systems associated to a precise TEE-guiding throughout the procedure, allows it to be performed as safely as possible when no other option is available.

A gray zone: Role of transesophageal echocardiography before atrial tachycardia catheter ablation.

There is a lack of studies in the literature directly investigating the relationship between atrial tachycardia (AT) and left atrial (LA)/left atrial appendage (LAA) thrombus, and current guidelines do not provide strong recommendations regarding the use of transesophageal echocardiography (TEE) before AT catheter ablation. This study aims to elucidate the relationship between AT and the presence of LA/LAA thrombus and contribute to the literature on the use of TEE before AT catheter ablation. This single-center retrospective observational study screened patients who underwent TEE between February 10, 2019, and February 10, 2023. Patients were assigned to the AT patient and control groups. TEE was conducted to exclude thrombus in the AT ablation group. The control group included patients who underwent TEE for interatrial septum evaluation and had LA imaging during TEE but did not have atrial arrhythmia. To mitigate bias between the AT patient group and the control group, they were randomized 1:1 using propensity-score matching (PSM). Following randomization, each group consisted of 49 patients. All analyses were conducted after PSM. There were no statistically significant differences between the AT patient and control groups in terms of baseline clinical characteristics and echocardiographic features. Additionally, no significant differences were found between the blood viscosities calculated at low and high shear rates in both groups. The study revealed a significant difference between the two groups in the presence of LA spontaneous echo contrast (SEC) (24.5% in AT group vs 0% in Control group, p = .001), but not in the presence of thrombi (8.2% in AT group vs 0% in Control group, p = .117). Compared to the control group, the presence of SEC was significantly higher in the AT patient group. The increased frequency of SEC in AT patients suggests the hypothesis that AT may contribute to LA stasis. The routine use of TEE before AT catheter ablation remains controversial, despite the presence of LA thrombus and SEC in the AT patient group. The clinical assessment of thrombus presence before the procedure must be conducted on a patient-specific basis.

Predictors of Device-Related Thrombus After Left Atrial Appendage Occlusion: TED-F2 Score

BackgroundLeft atrial appendage (LAA) occlusion (LAAO) is performed to prevent LAA thrombus in patients with atrial fibrillation (AF). The risk of device-related thrombus (DRT) on the atrial side of the LAAO device is 4%. Identifying patients at high risk of DRT would enable closer surveillance and more-aggressive anticoagulation to prevent post-LAAO DRT-related stroke. MethodsFrom the LAAO registry at The University of Kansas Medical Center, we identified patients who developed DRT. We chose 3× random controls from LAAO recipients without DRT. Predictor variables were obtained from transesophageal echocardiogram reports and/or images, transthoracic echocardiogram reports, and chart review. Implant depth was measured from the limbus of the left atrial ridge to the centre of the atrial aspect of the LAAO device, on a 45° transesophageal echocardiogram view. ResultsWe identified 26 patients with DRT (aged 77.7 ± 9.7 years; 34.6% female) and selected 78 unmatched controls without DRT. Univariate predictors of DRT, comprising a novel TED-F2 score, included history of venous Thromboembolism (23.1% vs 5.1%, P = 0.01), an LAA Emptying velocity ≤ 20 cm/s (45.8% vs 18.9%, P = 0.01), an implant Depth > 2 cm (34.6% vs 12.8%, P = 0.02), and an AF rhythm at implantation (50.0 % vs 11.5%, P = 0.0001). A TED-F2 score of ≥ 3 was very strongly associated with DRT—odds ratio 12.5 (95% confidence interval, 3.8-41.1, P < 0.0001). ConclusionsWe propose a novel risk score to predict development of DRT after LAAO, comprising history of venous Thromboembolism, LAA Emptying velocity ≤ 20 cm/s, implant Depth > 2 cm (1 point each), and an AF rhythm at implantation (2 points). A TED-F2 risk score of ≥ 3 identified patients who are at greatly elevated risk of developing DRT.

Validation of CT in comparison to TEE in routine workflow for detection of LAA thrombus in patients under oral anticoagulation presenting for left atrial ablation

Abstract Background Left atrial (LA) thrombus in patients (pts) presenting for LA ablation is an absolute contraindication to ablation. Although thrombi can still form despite the use of oral anticoagulation (OAC) in advance of the procedure. Transesophageal echocardiography (TEE) has been considered the gold standard for LAA thrombus detection. Additional cardiac computer tomography (CT) is often performed in pts with persistent atrial fibrillation (AF) or atrial tachycardia (AT). The aim of the study was in routine workflow 1) to identify the incidence of LAA thrombi in TEE and CT, 2) to search for an association in detecting LAA thrombi in the 2 methods and 3) to find out if the LAA flow velocity/ LA volume influences the thrombus detection. Methods Between 05/2018 and 10/2023 patients with AF/AT under OAC which were scheduled for a LA ablation were included. TEE and CT searching for LAA thrombus were carried out at intervals of up to 7 days. LAA flow velocity measured in the TEE. The LA volume which included LAA and excluded the pulmonary veins were obtained from the CT at the end-systole. Results Patients characteristics: 283 pts were included, mean age of 66y (+9y), 182 male, mean CHA2DS2-VASc score 3 [0-7]. All patients, mostly on NOACs (n=265), were orally anticoagulated. Mean LA volume (LA + LAA) was 158 ml (+45ml), LAA flow velocity was reduced (&amp;lt; 40 cm/s) in 119 pts (42%). In the majority of cases (73%), TEE and CT were performed at the same day or with an interval of 1 day. In 16 pts a LAA thrombus was detected using TEE,42 pts had SEC/Sludge but no solid thrombus. An LAA thrombus in the CT was described in 26 pts (10%), 6% couldn't definitively diagnose thrombi due to contrast recesses/flow phenomena in 16 pts. In 8 out of 34 events (23%) TEE and CT agreed on the diagnosis of a thrombus, in 6 cases during same-day examinations. 18 pts: LAA thrombus on CT, not on TEE (mean interval: 2d). 8 pts: LAA thrombus on TEE, not on CT (mean interval: 1.5d). In 71% (200 out of 283) of cases, CT and TEE agreed in ruling out a thrombus (p=0.358). LAA flow velocity and thrombus verification by TEE showed a significant correlation (p &amp;lt; 0.001). No correlation was found between the presence of a thrombus on CT and LA volume (p= 0.964). Discussion In 12% of the patients, all treated with OAC, a thrombus was described in at least one of the examinations or in both. Only in one out of four pts TEE and CT agreed on the diagnosis of a thrombus. It was notable that both examinations excluded thrombi in 70%. LAA flow velocity and thrombus verification in the TEE are significant correlated. LA volume and thrombus notification in CT are not related. Conclusion Routine diagnosis of LAA thrombus remains challenging, with frequent discrepancies between TEE, the gold standard, and CT. TEE results depend on the examining physician, while CT is limited by flow phenomena and scan timing.

Comparative effectiveness of different management strategies for left atrial appendage thrombus in patients on optimal NOAC therapy

Abstract Background Left atrial appendage (LAA) thrombus is the primary cause of stroke and systemic embolism in atrial fibrillation (AF). Novel oral anticoagulants (NOACs) effectively reduce the prevalence of LAA thrombosis and stroke risk. Nonetheless, there is no clear advice for patients with a NOAC-resistant thrombus, necessitating individualized decision-making without strong support of the current guidelines. Aims To analyze patients diagnosed with an LAA thrombus despite adequate NOAC therapy and to compare the efficacy of various therapeutic strategies in achieving thrombus resolution. Methods We retrospectively analyzed patients scheduled for cardioversion or catheter ablation of AF between 2014 and 2023 who were diagnosed with LAA thrombus despite being on optimal NOAC therapy. These patients underwent follow-up transesophageal echocardiography (TEE) or cardiac CT angiography. Changes in treatment modalities were divided into four groups: transition to an alternative NOAC, switch to a vitamin K antagonist (VKA), the addition of an antiplatelet agent, or the deliberate maintenance of the current treatment. Results We analyzed the data of 90 patients comprising 103 cycles of treatment. The patients were either on rivaroxaban (41%), apixaban (32%), dabigatran (15%) or on edoxaban (12%) at the time of the initial TEE. A change to a different NOAC was observed in 37% of cases, transition to a VKA in 22%, supplementation with antiplatelet therapy in 16%, while deliberate absence of treatment modification in 25% of cases. Subsequent follow-up TEE (or CT angiography in a minority of cases) was performed at a median of 68 [43 – 94] days from the baseline evaluation. Successful thrombus resolution was achieved in 72% of cases. Evaluation of therapeutic strategies revealed that any modification of treatment was three times more effective than deliberate no change in treatment; thrombus resolution was observed in 60 (81%) vs. 17 (59%) cases (OR 3.03 [1.18 - 7.75], p = 0.021). Nevertheless, no particular strategy demonstrated superior efficacy over others. Conclusions Resolution of LAA thrombus in patients already on adequate NOAC treatment may require a revision of the prior anticoagulation strategy; however, none of the commonly employed strategies appears to exhibit distinct superiority over the rest.

Predicting left atrial appendage thrombus in patients with persistent atrial fibrillation or flutter and no oral anticoagulation using machine-learning models

Abstract Background Atrial fibrillation and flutter (AF/AFL) increase the risk of thromboembolic events by promoting the formation of a left atrial appendage thrombus (LAT). We previously developed artificial intelligence (AI) models to predict LAT based on data from the multicentre, prospective LATTEE registry (Left Atrial Thrombus on Transoesophageal Echocardiography, n= 2489) establishing the utility of AI for identifying the presence of LAT. While our model is now available as an online calculator to date there is no data regarding the utility of our AI in guiding cardioversion in haemodynamically stable patients with persistent arrhythmia and no prior oral anticoagulation (OAC). Purpose To assess the performance of AI decision support to perform TOE or readmit the patient after at least 3 weeks of OAC. Methods In this study, we applied the LAT-AI model (based on 39 features) and the LAT-AI reduced model (based on 8 features) to patients with no or insufficient prior OAC, who underwent TOE before direct current cardioversion or catheter ablation (n=311). We excluded patients with paroxysmal arrhythmia, resulting in a final cohort of 150 patients originating from four sites. We investigated the sensitivity and specificity of the respective models to predict LAT based on the score thresholds established in previous studies (0.37 for the LAT-AI and 0.34 for the LAT-AI reduced). Results The median age in the external cohort was 66 (interquartile range 56-73), 59% were male, and 7.3% had AFL. LAT was found in 17 patients (11%). The LAT-AI model achieved 100% sensitivity (confidence interval [CI]: 40-100) and 12% specificity (95% CI: 7-18). The LAT-AI reduced model achieved 100% sensitivity (95% CI: 87-100) and 14% specificity (95% CI: 8-21). By applying the score threshold which has been derived in our prior studies for the the LAT-AI reduced model, the TOE-first approach would be chosen in 18% and no LAT would be found in this group, while the remaining 82% would be recommended for 3 weeks of OAC before TOE. Such approach could be used to identify patients at low risk of LAT to undergo TOE despite the lack of prior OAC, while the remaining patients at higher risk of LAT could potentially avoid repeated TOE thanks to the 3-week course of OAC before the first TOE. Conclusion AI scores allow high sensitivity for prediction of the presence of LAT in patients with AF/AFL irrespective of OAC treatment and have the potential to optimise the management of patients with indications for elective cardioversion and no prior or ineffective OAC.Simulated AI-supported decisionScreenshot of the online app

A novel score to predict left atrial appendage thrombus and sludge in patients with persistent atrial fibrillation on chronic anticoagulants

Abstract Introduction Left atrium (LA) and left atrial appendage (LAA) thrombus may occur during atrial fibrillation (AF) and atrial flutter (AFl), and potentially cause main embolic events. Sludge is a pre-thrombotic condition, associated with long term adverse outcomes. Current guidelines do not recommend to perform transesophageal echocardiography (TEE) before cardioversion (CV) of patients with persistent AF/AFl when at least 3 weeks of anticoagulation are administered with appropriate compliance. Instead, they suggest TEE before atrial ablations (Abl), even in anticoagulated patients. Evidence to support these approaches are weak and conflicting, due to not infrequent occurrence of peri-procedural stroke and several reports of not negligible prevalence of LAA thrombus finding. Purpose Aim of the study was to evaluate the real prevalence of LAA thrombus and sludge in a retrospective cohort of consecutive anticoagulated patients with persistent AF and AFl, who underwent TEE before a scheduled cardioversion or catheter ablation. Moreover, clinical and echocardiographic characteristics were analyzed to develop a score that could predict the individual risk of combined thrombus/sludge. Methods We conducted a retrospective, monocentric, observational study, recruiting 1037 consecutive patients with persistent AF/AFl referred to our center for CV or Abl. TEE had been always performed to rule out thrombus and sludge before procedures. We collected data about patients characteristics, medication and compliance, electrographic and echocardiographic findings and type of scheduled procedure. Data was compared in univariate and multivariate analysis to identify possible predictors of LAA thrombus and sludge, and we used the last significant results to create a predictive score with logistic regression analysis. We identified best cutoff value with ROC curve. Results 767 patients were included in final dataset. Mean CHA2DS2-VASc was 3.2. LA/LAA thrombus and sludge were identified in 63 subjects (8.21%), 17 thrombi (2.21%) and 45 sludge (5.86%). Presence of valvular AF (+1), previous stroke or TIA (+1.5), heart failure history (+1), ventricular systolic (LVEF &amp;lt; 45%)(+0.5) and diastolic (Lateral E/e’ &amp;gt; 9) dysfunctions (+1) were significantly associated to higher risk of thrombus/sludge occurrence, meanwhile AFl (-1) was associated to lower risk. A novel score, called HEELP score, was developed based on these variables, and a threshold of 1 point showed high sensitivity (89%) and remarkable negative predictive value (98%). Conclusion Thrombus and sludge prevalence is not infrequent in anticoagulated patients with persistent AF/AFl. A strategy to perform TEE before procedures in patients with high risk features according to our score could be effective in preventing main embolic events, but it has to be validated in further studies.LAA empty (1), sludge (2), thrombus (3)HEELP score