Left Atrial Appendage Thrombus Research Articles

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 (< 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 < 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 < 45%)(+0.5) and diastolic (Lateral E/e’ > 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

Omitting transesophageal echocardiography before catheter ablation of atrial fibrillation.

Data about necessity of performing transesophageal echocardiography (TOE) prior to every catheter ablation (CA) of atrial fibrillation (AF) is scarce. We aimed to evaluate the safety of an individualized risk-based approach to TOE with respect to thromboembolic cerebrovascular events (CVE) in patients undergoing CA for AF or left atrial tachycardia (AT). We performed a retrospective clinical study based on our institutional registry database. Patients undergoing CA for AF or left-sided AT following initial AF ablation at two participating centers were enrolled. Prior to the procedure, patients were scheduled for TOE only if they had a history of thromboembolic stroke, left atrial appendage (LAA) thrombus, or inappropriate anticoagulation regimen in the previous 3 to 4 weeks. The incidence of periprocedural cerebrovascular thromboembolic events was assessed. We analyzed 1155 patients (median age 70 years, 54.8% male, 48.1% had persistent AF/AT). In 261 patients, a TOE was performed; in 2 patients (0.7%), an LAA thrombus was detected, which led to cancellation of the catheter ablation; in 894 patients, the TOE was omitted. Of the 1153 (0.35%) patients who underwent ablation, 4 (0.35%) experienced a CVE (one TIA and three strokes). The rate of CVE in our study does not exceed that reported in most multicenter trials. The low event rates limited statistical analysis of possible risk factors for CVE. In all 4 patients with CVE, post-CVE imaging showed the absence of LAA thrombus. An individualized selective approach to TOE before catheter ablation of AF or left AT showed a very low risk of overt intraprocedural thromboembolic events for the population in our study. A further randomized controlled study is needed to determine whether TOE prior to catheter ablation without ICE could be omitted in patients with uninterrupted OAC without previous thromboembolic events or a history of left atrial thrombus.

Examining the prevalence of left atrial appendage thrombus in a cohort of acute stroke patients with an extended CT angiographic protocol.

Current guidelines recommend transthoracic echocardiography (TTE) for routine screening of cardiac emboli, however the visualisation of the left atrial appendage (LAA) where the thrombi are commonly found is poor. Transesophageal echocardiography (TEE) would provide better detectability of LAA thrombus, but it is time-consuming and semi-invasive method. Extending non-gated carotid computed tomography angiography (CTA) examination to the LAA could reliably detect thrombi, and could also aid treatment and secondary prevention of stroke. We extended the CTA scan range of acute stroke patients 4cm below the carina to include the left atrium and appendage. During the review we evaluated LAA thrombi based on contrast relations. We then used gradient boosting to identify the most important predictors of LAA thrombi from a variety of different clinical parameters. We examined 240 acute stroke patients' extended CTA scans. We detected LAA thrombi in eleven cases (4.58%), eight of them had atrial fibrillation. 23.75% of all patients (57 cases) had recently discovered or previously known atrial fibrillation. Windsack morphology was the most commonly associated morphology with filling defect on CTA. According to the gradient-boosting analysis, LAA morphology showed the most predictive value for thrombi. Our extended CTA scans reliably detected LAA thrombi even in cases where TTE did not, and showed that two patients' LAA thrombus would have been untreated based on electrocardiogram (ECG) monitoring and TTE. We also showed that the benefits of CTA outweigh the disadvantages arising from the slight amount of excess radiation.

Proteomic biomarkers for noninvasive left atrial appendage thrombus prediction in patients with atrial fibrillation

IntroductionThe 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. MethodsDeep 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. ResultsThe 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. ConclusionsProtein levels of PCYOX1 and decorin improve the predictive performance for LAAT in patients with nonvalvular AF.

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

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. 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. 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. 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.

Computed Tomography to Exclude Cardiac Thrombus in Atrial Fibrillation-An 11-Year Experience from an Academic Emergency Department.

Computed tomography (CT) could be a suitable method for acute exclusion of left atrial appendage thrombus (LAAT) prior to cardioversion of atrial fibrillation (AF) and atrial flutter (AFL) at the emergency department. Our aim was to present our experiences with this modality in recent years. This registry-based observational study was performed at the Department of Emergency Medicine at the Medical University of Vienna, Austria. We studied all consecutive patients with AF and AFL who underwent CT between January 2012 and January 2023 to rule out LAAT before cardioversion to sinus rhythm was attempted. Follow-ups were conducted by telephone and electronic medical records. The main variables of interest were the rate of LAAT and ischemic stroke at follow-up. A total of 234 patients (143 [61%] men; median age 68 years [IQR 57-76], median CHA2DS2-VASc 2 [IQR 1-4]) were analyzed. Follow-up was completed in 216 (92%) patients after a median of 506 (IQR 159-1391) days. LAAT was detected in eight patients (3%). A total of 163 patients (72%) in whom LAAT was excluded by CT were eventually successfully cardioverted to sinus rhythm. No adverse events occurred during their ED stay. All patients received anticoagulation according to the CHA2DS2-VASc risk stratification, and no patient had suffered an ischemic stroke at follow-up, resulting in an incidence risk of ischemic strokes of 0% (95% CI 0.0-1.2%). LAAT was rare in patients admitted to the ED with AF and AFL who underwent cardiac CT prior to attempted cardioversion. At follow-up, no patient had suffered an ischemic stroke. Prospective studies need to show whether this strategy is suitable for the acute treatment of symptomatic AF in the emergency setting.

Use of 3D echocardiography facilitates analysis of thrombolytic efficacy in patients with persistent atrial fibrillation.

This study seeks to identify the anticoagulant efficacy of rivaroxaban treatment on thrombi detected using echocardiography of the left atrial appendage in 275 patients with persistent atrial fibrillation (AF). During follow-up after 9 to 24 weeks of Rivaroxaban treatment, patients were divided into 'effective group' (n = 143) and 'ineffective group' (n = 132) according to the thrombolytic effect of the drug. Left atrial diameter (LAD), left atrial ejection fraction (LAEF), left ventricular ejection fraction (LVEF), mean diameter of left atrial appendage (LAADmean), angle between left atrial appendage and left atrial (LAA-A), velocity of blood flow in left atrial appendage (LAA-v) and thrombus size were compared before and after drug administration. Following treatment, LAEF, LVEF and LAA-v values were greater and LAD and LAADmean values were lower in the effective (P<0.05). Logistic regression analysis showed significant correlations of LAD, LAEF, LVEF, LAA-A and LAA-v with anticoagulant efficacy (P<0.05). The efficacy of Rivaroxaban in treatment of left atrial auricular thrombosis in patients with persistent AF was correlated with LAD, LAEF, LVEF, LAA-A and LAA-v. Multivariate logistic regression analysis further revealed LAEF (OR 1.7, 95% CI 0.45-16.9, P=0.008), 3D-EF (OR 6.4, 95% CI 1.06-16.9, P=0.039), and left ventricular global longitudinal strain (GLS) (OR 18.0, 95% CI 1.38-35.68, P=0.028) as factors related to left atrial appendage thrombus. Echocardiography with global longitudinal strain assessment could be effectively utilized to evaluate the functional parameters of LAA and thus aid in predicting the safety of Rivaroxaban as an anticoagulation agent.

Should left atrial appendage closure be considered in resistant left atrial appendage thrombus cases? 'Former Foe, New Ally'.

The study explores left atrial appendage closure (LAAC) as a safe and effective alternative to anticoagulation for atrial fibrillation (AF) patients at high bleeding risk. Complications, such as cardioembolic events due to left atrial appendage thrombus (LAAT), highlight the need for alternative stroke prevention strategies. This research assesses LAAC's safety and efficacy in patients with LAAT, aiming to offer valuable insights into its potential as a viable option for stroke prevention in such cases. The study included 205 patients who underwent LAAC using specific devices between September 2015 and February 2023. Among them, 32 patients had persistent LAAT. Baseline characteristics, antithrombotic medications, risk scores, and LAAC indications were documented. Patients were followed to monitor significant clinical events like stroke, cardiovascular mortality, and all-cause mortality. The mean age was 71.9 and mostly female. Indications for LAAC were ischemic cerebrovascular events (CVE) despite anticoagulation (25%), bleeding complications (major/minor, 37.5% each), or both. Successful LAA closure was achieved in all cases, with minimal pericardial effusion in one. One-month follow-up showed no major events or device-related issues. Median follow-up of 16.5 months saw 21.9% non-cardiac deaths. The study underscores LAAC's efficacy for stroke prevention in patients with persistent LAAT. The LAAC in cases of LAAT, whether pursued initially or as a deferred approach, demonstrates feasibility and safety, exhibiting notable procedural success and minimal incidence of periprocedural complications.

Epicardial fat and left atrial appendage thrombosis in patients with persistent atrial fibrillation

BACKGROUND: Excessive deposition of the epicardial adipose tissue (EAT) plays a role in the development of a number of cardiovascular diseases, including ischemic stroke. As more than half of strokes in patients with atrial fibrillation (AF) are cardioembolic, and the source of thromboembolic complications is the left atrial appendage (LAA), it can be assumed that excess EAT contributes to the development of LAA thrombus. The literature does not present the results of a study of the relationship between the amount of EAT and LAA thrombus in patients with AF, which makes it relevant to study this issue.AIM: to study the effect of EAТ on LAA thrombosis and the emptying flow velocity from the LAA in patients with persistent AF.MATERIALS AND METHODS: The patients with persistent AF underwent transesophageal and transthoracic echocardiography before the planned cardioversion. The transesophageal echocardiography measured the emptying flow velocity from the LAA, and the thickness of the interatrial septum and the left lateral ridge, the average value of which was used to estimate the amount of left atrial EAT. The thickness of the anterior wall of the right ventricular EAT was measured by transthoracic echocardiography.RESULTS: The LAA thrombus was detected in 42 (8.6%) patients of 486 patients with persistent AF (age 64.0 [59.0; 70.0] years, men 58.0%). Patients with thrombus had greater thickness of the left atrial EAT (9.30 [9.05; 9.55] vs. 7.70 [7.03; 8.28] mm, p&lt;0.001) and of the right ventricular EAT (8.05 [7, 90; 8.90] versus 7.80 [7.20; 8.40] mm, p = 0.001), but the emptying flow velocity from the LAA is lower (20.0 [14.0; 26.0] versus 32.0 [26.0; 39.0] cm/s, p&lt;0.001). Area under the receiver operator characteristic curve for the thickness of the left atrial EAT, as a predictor of the LAA thrombosis, was significantly larger than for the thickness of the right ventricular EAT: 0.947 (0.923–0.965) versus 0.661 (0.617–0.703), p&lt;0.001. The thickness of the left atrial EAT more than 8.6 mm increases the chances of LAA thrombosis by 70.1 (24.1–204.2) times. Analysis of multiple linear regression did not reveal an independent effect of the thickness of the left atrial EAT (b = -0.0951±0.6163, p = 0.877) and of the right ventricular EAT (b = 0.6764±0.4383, p = 0.124) on the emptying flow velocity from the LAA.CONCLUSION: The increased of the thickness of EAT increases the chances of developing LAA thrombosis in patients with persistent AF, but does not affect on the emptying flow velocity from the LAA.

Non-electrocardiography-gated dual-energy cardiac CT angiography for assessment of left atrial appendage thrombus

ObjectiveTo explore the diagnosis value of a low dose, dual-energy cardiac computed tomography angiography (CTA) with non-electrocardiography-gated (non-ECG-gated) in detecting left atrial appendage thrombus. MethodsConsecutive patients with atrial fibrillation who underwent cardiac CTA protocol (dual-energy scan for arterial phase and conventional scan for delayed phase) were prospectively enrolled. LAA lesions were proved by clinical comprehensive diagnosis, the final study included 18 cases with LAA thrombus and 48 cases with circulatory stasis. Quantitative parameters derived from dual-energy images were measured for the LAA lesions, including the conventional CT attenuation value (CT value), iodine concentration (IC), normalized iodine concentration (NIC), effective atomic number values (Zeff) and energy spectrum curve slope (Slope). The differences between LAA thrombus group and circulatory stasis group were compared by independent t-test or Wilcoxon rank sum test regarding to the normality test. The diagnosis performance of the dual-energy parameters was assessed using receiver operating characteristic (ROC) curve analysis and area under curve (AUC). ResultsAll the dual-energy parameters were demonstrated significantly difference between LAA thrombus and circulatory stasis group (P＜0.05), and showed better diagnostic performance than the conventional CT value. ROC analysis revealed IC was the most predictive parameter with AUC equal to 0.836. The radiation dose in the arterial phase was (2.64 ​± ​0.66) mSv. ConclusionDual-energy CTA scanning shows convincing diagnostic performance in detecting left atrial appendage thrombus with lower radiation dose, and may help reduce the need for delayed phase scan.

Development and validation of a nomogram superior to CHADS2 and CHA2DS2-VASc models for predicting left atrial appendage dense spontaneous echo contrast/left atrial appendage thrombus.

Atrial fibrillation (AF) is one of the most frequently encountered arrhythmias in clinical practice, with stroke triggered by detachment of left atrial appendage thrombus (LAAT) after AF being its most critical complication. The purpose of this study was to construct a nomogram model for forecasting left atrial appendage (LAA) dense spontaneous echo contrast (SEC) and LAAT to accurately identify patients at high risk for stroke. A retrospective analysis was conducted on 433 patients with AF receiving transesophageal echocardiography (TEE) in the First Affiliated Hospital of Soochow University from October 2019 to July 2022. These patients were assigned into a non-dense SEC/LAAT group or a dense SEC/LAAT group. We constructed a nomogram model dependent on the odds ratios (ORs) of logistic regression and subsequently compared its performance with two models, CHADS2 and CHA2DS2-VASc. Female gender, high D-dimer level, low left ventricular ejection fraction, low left atrial ejection fraction, and low left atrial reservoir strain rate were found to be independent factors for predicting LAA SEC/LAAT, with OR values and 95% confidence intervals of 2.811 (1.445-5.469), 2.460 (1.230-4.921), 0.961 (0.927-0.996), 0.950 (0.932-0.967), and 0.173 (0.035-0.848), respectively. The consistency statistic of the nomogram based on these given predictive factors was 0.921, and the calibrated consistency statistic was 0.903. According to receiver operation curve analysis and decision curve analysis, the nomogram was demonstrated to be superior to the CHADS2 and CHA2DS2-VASc models in predicting LAA dense SEC/LAAT. The net reclassification improvement and integrated discrimination improvement of the nomogram were 0.449 (0.324-0.575) and 0.461 (0.408-0.515), when compared with the CHADS2 model, and were 0.521 (0.411-0.632), and 0.432 (0.400-0.504), respectively, when compared with the CHA2DS2-VASc models. The nomogram model constructed in this study demonstrated excellent performance in predicting LAA dense SEC/LAAT, displaying a superior ability to that of the CHADS2 and CHA2DS2-VASc models.

Associations of the left atrial epicardial fat thickness with the thrombosis prevalence and left atrial appendage flow velocity in patients with persistent non-valvular atrial fibrillation

Aim. To study the associations of the left atrial epicardial fat (LAEF) thickness with the thrombosis prevalence and left atrial appendage (LAA) flow velocity in patients with persistent non-valvular atrial fibrillation (AF).Material and methods. Transesophageal echocardiography in 475 patients with persistent non-valvular AF (men 58,9%, age 64,0 (58,3-70,0) years) assessed LAA flow velocity, interatrial septum and left lateral ridge thickness. Their average thickness was used to estimate the LAEF volume.Results. LAA thrombus was detected in 42 (8,8%) patients. LAA flow velocity without thrombus was 32,0 (26,0-39,0) cm/s, with thrombus — 20,0 (14,0-25,8) cm/s (p&lt;0,0001). Depending on the LAEF thickness, patients were divided into 3 tertile groups: group 1 (n=168) — 5,6-7,4 mm, group 2 (n=154) — 7,45-8,2 mm, group 3 (n=153) — 8,25-10,9 mm. In group 1, no thrombus was detected, in group 2, thrombus was detected in 2 (1,3%) patients, in group 3 — in 40 (26,0%) patients (p&lt;0,0001). In the absence of LAA thrombus, flow velocity in the selected groups did not differ (32,0 (26,0-39,0) cm/s, 31,0 (26,0-7,8) cm/s and 31,5 (25,0-40,0) cm/s, (p=0,9514)).Conclusion. EFL thickness, calculated as the average of interatrial septum and left lateral ridge thickness, can be used to study the relationship between epicardial obesity and LAA thrombosis in patients with AF. In patients with persistent non-valvular AF with a LAEF thickness &gt;8,2 mm, LAA thrombosis occurs more than 40 times more often than in patients with a lower LAEF thickness. The influence of LAEF thickness on LAA flow velocity was not revealed in the pre­sent study.

The impact of contrast retention on thrombus formation risks in patients with atrial fibrillation: A numerical study

BackgroundContrast retention (CR) is an important predictor of left atrial appendage thrombus (LAAT) and stroke in patients with non-valvular atrial fibrillation (AF). We sought to explore the underlying mechanisms of CR using computational fluid dynamic (CFD) simulations. MethodsA total of 12 patients with AF who underwent both cardiac computed tomography angiography (CTA) and transesophageal echocardiography (TEE) before left atrial appendage occlusion (LAAO) were included in the study. The patients were allocated into the CR group or non-CR group based on left atrial appendage (LAA) angiography. Patient-specific models were reconstructed to evaluate time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), and endothelial cell activation potential (ECAP). Additionally, the incidence of thrombosis was predicted using residence time (RT) at different time-points. ResultsTAWSS was lower [median (Interquartile Range) 0.27 (0.19–0.47) vs 1.35 (0.92–1.79), p < 0.001] in LAA compared to left atrium. In contrast, RRT [1438 (409.70–13869) vs 2.23 (1.81–3.14), p < 0.001] and ECAP [122.70 (30.01–625.70) vs 0.19 (0.16–0.27), p < 0.001)] was higher in the LAA. The patients in the CR group had significantly higher RRT [(mean ± SD) 16274 ± 11797 vs 639.70 ± 595.20, p = 0.009] and ECAP [610.80 ± 365.30 vs 54.26 ± 54.38, p = 0.004] in the LAA compared to the non-CR group. Additionally, patients with CR had a wider range of thrombus-prone regions [0.44(0.27–0.66)% vs 0.05(0.03–0.27)%, p = 0.009] at the end of the 15th cardiac cycle. ConclusionsThese findings suggest that CR might be an indicator of high-risk thrombus formation in the LAA. And CT-based CFD simulation may be a feasible substitute for the evaluation of LAA thrombotic risk in patients with AF, especially in patients with CR.

Left atrial strain time integral evaluated by two-dimensional speckle tracking predicts left atrial appendage dysfunction in patients with acute ischemic stroke.

Cardioembolic stroke is a serious disease with poor prognosis, whose main embolic source is the left atrial appendage (LAA). Left atrial (LA) strain evaluated by the two-dimensional (2D) speckle tracking technique has been proposed. However, the commonly used peak LA strain reflects only LA reservoir function. The LA strain also includes indicators of the other LA functions, such as booster pump function, which reflects active contraction of the LA. This study aimed to investigate whether a newly developed parameter, the left atrial strain time integral (LASTI), can evaluate LAA dysfunction more accurately in patients with acute stroke. We measured LA strain using a 2D speckle tracking method in 168 patients with acute stroke and 20 age-matched control subjects. LASTI was calculated as the area under the LA strain curve in one cardiac cycle. LAA dysfunction was defined as LAA thrombus and/or severe spontaneous echo contrast by transesophageal echocardiography. LASTI was significantly lower in patients with LAA dysfunction than those without. LASTI was a better correlation with LAA blood flow velocity measured by transesophageal echocardiography than peak LA strain. Multivariate logistic regression analysis showed that LASTI was an independent predictor of LAA dysfunction after adjustment for conventional risk factors. LASTI can be a feasible parameter for predicting LAA dysfunction in patients with acute stroke.

Left atrial appendage thrombus with severe mitral stenosis: Responders and non-responders to anticoagulation

Introduction and objectiveMitral stenosis (MS) is one of the most frequently observed valvular heart lesions in developing countries and is due to different etiologies. The effects of anticoagulation in different types of left atrial appendage (LAA) are unknown. The current study aimed to determine the resolution of LAA thrombus on transesophageal echocardiography (TEE) after three months of optimal anticoagulation in patients with different types of LAA at baseline cardiac computed tomography of patients with severe MS. MethodsThis prospective cohort study observed the frequency of LAA thrombus resolution after three months of anticoagulation therapy in patients with severe MS. The response rate in different morphologies of LAA and locations was also assessed. Thrombus resolution after three months of warfarin therapy was assessed on repeat TEE. ResultsA total of 88 patients were included, mean age 37.95±11.87 years. Repeat TEE showed thrombus resolution in only 27.3% of patients. The rate of thrombus resolution was 8/12 (66.7%), 4/28 (14.3%), 8/36 (22.2%), and 4/12 (33.3%) for patients with cactus, cauliflower, chicken wing, and windsock LAA type, respectively. The resolution rate was 0/12 (0%), 4/44 (9.1%), and 20/32 (62.5%) for patients with thrombus in the base, body, and tip of the LAA, respectively. ConclusionThe cactus type of LAA morphology and thrombus at the LAA tip responded well to three months of anticoagulation, however, patients with thrombus in the LAA base and body and cauliflower and chicken wing morphology were non-responders and could benefit from early referral for surgical management.

Abstract 39: Slow-Flow in the Left Atrial Appendage on Cardiac CT in Patients With Acute Ischemic Stroke

Background: Slow-flow in the left atrial appendage (LAA) is thought to be associated with an increased risk of thrombus formation and stroke. We studied LAA slow-flow on cardiac CT in patients with acute ischemic stroke (AIS). Method: We used data from Mind the Heart, a prospective cohort study of AIS patients who underwent ECG-gated cardiac CT during the acute imaging protocol. We compared baseline characteristics, functional outcome (modified Rankin scale), stroke recurrence and major adverse cardiovascular events (MACE) after 2-year follow-up between patients with LAA thrombus (filling defect &lt;100 Hounsfield Unit [HU]), slow-flow (filling defect, but with ≥100 HU) and normal filling. We performed a sensitivity analysis restricted to cryptogenic stroke patients. Results: Of 421 patients, 31 (7%) were classified as LAA thrombus, 69 (16%) as LAA slow-flow and 321 (76%) as normal LAA filling. Patients with LAA thrombus or slow-flow more often had atrial fibrillation compared to normal filling (45%, 39%, 9%, p&lt;0.001, respectively). LAA thrombus patients had more severe strokes compared to slow-flow and normal filling (NIHSS 18 [IQR: 9-22], 6 [IQR: 3-17], 5 [IQR: 2-11], p&lt;0.001). There was no significant difference between LAA slow-flow patients and normal LAA filling in functional outcome (acOR: 0.8, 95%CI 0.5-1.4), recurrent ischemic stroke (aHR 0.8, 95%CI: 0.3-1.9) or MACE (aHR 1.2, 95%CI 0.7-2.1). In cryptogenic stroke patients (n=156), LAA slow-flow was associated with a higher risk of recurrent stroke (aHR: 4.1, 95%CI: 1.1-15.7) compared to normal LAA filling (Figure 1). Conclusion: Patients with LAA slow-flow had similar characteristics compared to patients with a thrombus, including high rates of atrial fibrillation, but had less severe strokes. Compared to patients with normal filling, LAA slow-flow was not significantly associated with worse functional outcome or MACE, but was associated with recurrent stroke in patients with cryptogenic stroke.

Abstract WP23: Hemorrhagic Transformation Following Anticoagulation in Victims of Acute Ischemic Stroke Secondary to Intra-Cardiac Thrombi

Introduction: Hemorrhagic transformation (HT) following acute ischemic stroke (AIS) is a common consideration especially when therapeutic anticoagulation is indicated in cases such as left ventricular or left atrial appendage thrombi. Although there have been multiple studies investigating the safe timing of anticoagulation initiation following AIS in patients with atrial fibrillation, the results varied. Evaluating the infarct volume and correlating it to time of anticoagulation initiation and HT can be detrimental to patient safety. Methods: We performed a retrospective review of all patients who were diagnosed with AIS secondary to cardio-embolic mechanisms and were admitted to our hospital between January 1, 2018, and December 31, 2022. The inclusion criteria consisted of patients aged 18 to 100 years who were found to have intra-cardiac thrombi and were initiated on anticoagulation within 80 hours of symptom onset. Infarct volume was measured using the ABC/2 formula. Statistical analysis was conducted using the R statistical program. For variables with a normal distribution, we used the mean and standard deviation (SD), and for variables with skewed distribution, we reported the median with interquartile range (IQR). Results: A total of 597 patient charts were reviewed for this study. After applying the inclusion criteria, 36 patients were deemed eligible for inclusion in the analysis. Among the included patients, a majority were male, constituting 80.6% (n=29) of the sample. The infarct volume among the included patients ranged from 0 ml to 100 ml. A breakdown of infarct volumes is as follows: Twenty-three patients (63.9%) had infarct volumes of 10 ml or less. Seven patients (19.4%) had infarct volumes ranging between 11 - 20 ml. Six patients (16.7%) had infarct volumes that exceeded 21 ml, with the largest infarct measuring 100 ml. There was no clinically significant HT. There were no surgical interventions required for any of our study subjects. Conclusion: The initiation of anticoagulation within 80 hours following AIS secondary to intra-cardiac thrombi may be safe, especially in patients with infarct volumes of 20 ml or less when using the ABC/2 formula.