Left Atrial Appendage Thrombus Formation Research Articles

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

Introduction and objectivesThe 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.

Pre-Clinical Evaluation of Left Atrial Appendage Closure Device in Mitigating Risk of Stroke in Patients with Atrial Fibrillation: Promising Results from Animal Trials with Future Prospects

Abstract: Atrial fibrillation (AF) is the most common clinical disorder of cardiac arrhythmia in geriatrics, characterized by the presence of disorganized and irregular electrical activity in atrial myocardium, which leads to worsening of the heart's systolic function. Left atrial appendage (LAA) is a tubular, tiny aperture construction, connecting the left atrium (LA) with separate structure from LA with distinctive mechanical, hormonal, and structural properties. AF and Mitral valve regurgitation disease elevate the chances of thrombus formation in LAA, these ultimately turns into stroke. Obstructing thrombus by using a Left Atrial Appendage Closure Device (LAAC) and preventing it from entering internal carotid arteries, the risk of LAA thrombosis can be decreased. This article serves as a comprehensive compilation detailing the successful development and implantation of Left Atrial Appendage Closure (LAAC) Device with its novel design and geometry in two pigs (pre-clinical evaluation), showcasing promising results that have future implications for addressing cardiovascular disease in humans.

Left atrial appendage morphology and mitral annular plane systolic excursion predict stroke in patients with atrial fibrillation and high thromboembolic risk

Abstract Background Previous research has revealed a relationship between the morphology and function of the left atrial appendage (LAA) and the rate of thromboembolic events in patients with atrial fibrillation (AF). There is limited data on the impact of the left ventricular (LV) function on LAA thrombus formation. Emptying of the LAA depends on the active contraction of this structure as well as on the passive motion due to external compression from the LV base during ventricular diastole. Purpose Given these considerations the goal of this study was to investigate by transesophageal and transthoracic echocardiography the morphology and function of the LAA in relationship with the LV function and to assess the impact on incidence of stroke in a group of patients with AF with high thromboembolic risk who underwent TEE-guided direct current cardioversion. Methods We included 148 patients (age 65 ±11 yrs, 79men, median CHA2DS2-VASc score 4 (IQR 2-6), left ventricular ejection fraction 48±11%), who underwent transesophageal echocardiography before cardioversion. During a median follow-up period of 23 months (range 1-107) 34 patients developed stroke or TIA. Results The distribution of the four LAA morphologies (Figure 1) was: Cactus [47 (32%)], Cauliflower [30 (20%)], Windsock [38(26%)], and Chicken Wing [33 (22%)]. During the follow-up period stroke/TIA occurred significantly more frequently in patients with cactus or cauliflower LAA morphology vs. patients with windsock or chicken wing morphology (25 (35%) vs 9 (11%); p value=0.001). Patients who developed stroke or TIA had significantly lower MAPSE vs patients with event free survival (8±3 vs 12±3mm; p value=0.001). Kaplan-Meier survival curves for different categories of MAPSE and LAA morphology are shown in Figure 2. The significant relationship between MAPSE and stroke-free survival was retained in Cox multivariable analysis that included LAA morphology, CHA2DS2-VASc score and AF types. This association was present whether MAPSE was entered into the multivariable model as a continuous or dichotomized variable. Conclusions In patients with high thromboembolic risk, MAPSE predicts the occurrence of stroke independent of LAA morphology and CHA2DS2-VASc score. This phenomenon could be related to the impact LV diastole on LAA emptying.

The impact of aging and atrial fibrillation on thrombus formation in-silico

Abstract Background Atrial fibrillation (AF) is an age-related cardiac arrythmia that underlies one third of all strokes, with thromboemboli commonly originating from the left atrial appendage (LAA). Personalised in-silico modelling of Virchow’s triad (blood stasis, hypercoagulability and endothelial damage) can improve stroke risk assessment metrics, such as the CHA2DS2-VASc score, by providing quantitative mechanistic information [1]. The ability to quantify the impact of aging may play a critical role in patient stratification and therapy selection to reduce the risk of AF-related stroke. Aim We aim to perform in-silico modelling to quantify the effect of aging and AF on thrombus formation in the LAA by using advanced computational tools to capture blood flow, clotting mechanisms and endothelial damage [2]. Methods A virtual physiological LA model was derived from cardiac Cine MRI from an adult AF patient imaged during sinus rhythm (SR). Biomarkers for a geriatric patient were obtained from literature and applied as: i) elevated plasma fibrinogen concentration and ii) longer thrombin time-to-peak (ttP) [3]. Blood flow was simulated in SR and AF conditions for 5 cardiac cycles in the LA for both ages (totalling 4 test cases). The catalytic conversion of fibrinogen to a fibrin clot by thrombin was modelled to mimic hypercoagulability [2]. The site of endothelial injury was prescribed in the middle of the LAA. The area under curve for the fibrin concentration (Fn AUC) was measured to quantify thrombus formation. Results In the two SR cases, LA blood flow velocity increased to a maximum of 1.8 m/s after 0.6 s with a mean of 0.63 m/s during the cardiac cycle, while the two AF cases showed 1.3 m/s and 0.39 m/s, respectively, corresponding to a 38% decrease in AF. Peak velocity in the LAA was 0.35 m/s during SR and 0.18 m/s in AF. The fibrin concentration in the adult-SR case rose to 1.1 mmol/m³ over the first cardiac cycle, but both thrombin and fibrin were washed out of the LA after 1.5 s, with a Fn AUC of 0.045mmol s/m³ (Fig. 1a). The geriatric-SR case sustained fibrin generation throughout the 5 cardiac cycles reaching 3.1 mmol/m³, an Fn AUC of 2.4 mmol s/m³, and the formation of an LAA thrombus (Fig. 1b). Similarly, the adult-AF and geriatric-AF cases also saw continuous growth to 5.0 and 7.4 mmol/m³, with Fn AUCs of 6.4 and 12.6 mmol s/m³, respectively, with formation of a thrombus in the LAA in both (Fig. 1c and d). The thrombus formed in the adult-AF case was 25% larger than the geriatric-SR case, while thrombus in the geriatric-AF case was 80% larger. Conclusions This investigation quantifies the increased risk of LAA thrombus formation in older patients, with an Fn AUC increase of 55% between adult and geriatric in SR and a 100% increase when combining geriatric biomarkers with AF conditions. With further validation on larger patient cohorts, this novel in-silico tool may improve our understanding of the risks in AF-related stroke.

Predictive value of echocardiography combined with CT angiography for left atrial appendage thrombosis in patients with non-valvular atrial fibrillation.

The aim of this study was to investigate the detection rate of left atrial appendage thrombus (LAAT) formation in non-valvular atrial fibrillation (NVAF) patients using three methods and the efficacy of combined electrocardiogram (ECG) and Computed Tomography Angiography (CTA) in the diagnosis of LAAT. A total of 80 NVAF patients who underwent Transesophageal echocardiography (TEE) at our hospital from August 2018 to August 2022 were included in the study. The baseline data of patients were observed, and the positive rates of LAAT formation by ECG, CTA, and TEE were compared. The efficacy of combined ECG and CTA in the diagnosis of LAAT was also evaluated. Among the 80 NVAF patients, 23 were LAAT positive and 57 were LAAT negative. There were statistically significant differences between the two groups in terms of age, body mass index (BMI), N-terminal prohormone of brain natriuretic peptide NT-probNP, fibrinogen, CHA2DS2-VASC [congestive Heart Failure, Hypertension, Age (75 or older), diabetes mellitus, stroke, vascular disease, age (65-74), sex category] score, paroxysmal atrial fibrillation, renal insufficiency, D-dimer, heart failure, and serum uric acid (p<0.05). The positive rate of LAAT detected by ECG combined with CTA was closest to the gold standard TEE, but the difference was not statistically significant (p>0.05). Statistically significant differences were found between LAAT positive and negative patients in various parameters related to left atrial and left ventricular dimensions and function (p<0.05), while some parameters showed no significant differences (p>0.05). ECG combined with CTA has a high diagnostic value for LAAT formation in NVAF patients, with a high degree of confidence and reduced patient intolerance. The sensitivity, accuracy, and negative predictive value of ECG combined with CTA for the diagnosis of LAAT formation in NVAF patients are high and have good predictive value.

Left atrial appendage thrombus formation despite oral anticoagulation: what can we do when there is nothing to offer?

Left atrial appendage thrombus formation despite oral anticoagulation: what can we do when there is nothing to offer?

Electric cardioversion in patients treated with oral anticoagulants: embolic material in the left atrial appendage.

Atrial fibrillation (AF) remains the most common arrhythmia. The sinus rhythm restoration procedure without adequate anticoagulant preparation may lead to a thromboembolic event in approximately 5-7% of patients. The initiation of oral anticoagulation significantly reduces this risk by inhibiting formation of embolic material in the heart cavities, especially in the left atrial appendage (LAA). However, there is a group of patients who develop embolic material in the LAA despite oral anticoagulation treatment. The best treatment method to dissolve thrombus in the LAA is not clear, due to the lack of studies with adequate power and endpoints that can determine the best management strategy. We present clinical trials comparing the efficacy and safety of oral anticoagulants in patients undergoing AF cardioversion. We evaluate the frequency of LAA thrombus formation in patients with AF on treatment with oral anticoagulants. Furthermore, we discuss the effectiveness of various treatment strategies on LAA thrombus resolution.

Computational Flow Dynamic Analysis in Left Atrial Appendage Thrombus Formation Risk: A Review

Atrial fibrillation (AF) is a common cardiac arrhythmia characterized by irregular and rapid electrical activity in the atria, leading to ineffective contraction and poor blood flow. More than 90% of the left atrial (LA) thrombi that cause thromboembolic events during atrial fibrillation (AF) develop in the left atrial appendage (LAA). AF modifies the hemodynamics of the left atrium, which can result in thrombosis of the LAA, systemic embolism, and stroke. The current options to reduce thromboembolic events are oral anticoagulation, surgical LAA exclusion, or percutaneous LAA occlusion. However, the mechanism underlying thrombus development in the LAA remains poorly understood. Computational fluid dynamics (CFD) analysis can be used to better understand the risk of thrombus formation and subsequent embolic events. CFD enables the simulation and visualization of blood flow patterns within the heart, including complex structures such as the LAA. Using CFD, researchers can analyze the hemodynamics of blood flow, identify areas of stagnation or turbulence, and predict the risk of thrombus formation. The correlation between blood flow dynamics, atrial fibrillation, and the risk of stroke has been highlighted by CFD studies investigating the underlying mechanism of thrombus formation in the LAA. This review study intends to provide a comprehensive overview of the factors involved in thrombus formation and their implications for clinical practice by synthesizing the insights acquired from these CFD studies.

Association Between Left Atrial Appendage Thrombus Formation and Monocyte/HDL Ratio in Patients with Acute Ischemic Stroke

Objective: There is an apparent link between thrombus formation and inflammation. Monocyte/HDL ratio (MHR) has been determined as an inflammatory marker and associated with many cardiovascular disorders like coronary artery disease, acute coronary stent thrombus, coronary thrombus burden and atrial fibrillation (AF). The purpose of this study was to elucidate the association between MHR and left atrial appendage thrombus formation (AATF) in patients with acute ischemic stroke.&#x0D; Methods: A total of 69 patients with the diagnosis of acute ischemic stroke were retrospectively enrolled in the study. Demographic, clinical and echocardiographic data were collected retrospectively from the patients’ records. MHR and neutrophil/lymphocyte ratio (NLR) were calculated from the present laboratory data.&#x0D; Results: There was a significant positive correlation between MHR and NLR (r=0.6; p

The Strengths and Weaknesses of Left Atrial Appendage Ligation or Exclusion (LARIAT, AtriaClip, Surgical Suture)

Left atrial appendage (LAA) epicardial exclusion has been associated with addressing 2 potential deleterious consequences attributed to the LAA, namely, thrombus formation and an arrhythmogenic contributor in advanced forms of atrial fibrillation. With more than 60 years of history, the surgical exclusion of the LAA has been firmly established. Numerous approaches have been used for surgical LAA exclusion including surgical resections, suture ligation, cutting and non-cutting staples, and surgical clips. Additionally, a percutaneous epicardial LAA ligation approach has been developed. A discussion of the various epicardial LAA exclusion approaches and their efficacy will be discussed, along with the salient beneficial affects on LAA thrombus formation, LAA electrical isolation and neuroendocrine homeostasis.

The pathogenesis of aging-induced left atrial appendage thrombus formation and cardioembolic stroke in mice is influenced by inflammation-derived matrix metalloproteinases

Elderly people without atrial fibrillation (AF) still have a high incidence of cardioembolic stroke, suggesting that thrombus formation within the left atrial appendage (LAA) may also occur in an AF-independent manner. In the present study, we explored the potential mechanisms for aging-induced LAA thrombus formation and stroke in mice. We monitored stroke events in 180 aging male mice (14–24 months) and assessed left atrium (LA) remodeling by echocardiography at different ages. Mice that had stroke were implanted with telemeters to confirm AF. Histological features of LA and LAA thrombi were examined, as well as collagen content, expression of matrix metalloproteinases (MMPs), and leukocyte density in the atria at different ages, in mice with or without stroke. Also, the effects of MMP inhibition on stroke incidence and atrial inflammation were tested. We detected 20 mice (11 %) with stroke, 60 % of which were within 18–19 months of age. Although we did not detect AF in mice with stroke, we detected the presence of LAA thrombi, suggesting that stroke originated from the hearts of these mice. Compared with 18-month-old mice without stroke, 18-month-old stroke mice had enlarged LA with a very thin endocardium, that was associated with less collagen and heightened MMP expression in the atria. During aging, we found that the expression of mRNAs for atrial MMP7, MMP8, and MMP9 peaked at 18 months, which closely correlated with reductions in collagen content and the time-window for cardioembolic stroke in these mice. Treatment of mice with an MMP inhibitor at 17–18 months of age reduced atrial inflammation and remodeling, and stroke incidence. Taken together, our study demonstrates that aging-induced LAA thrombus formation occurs through a mechanism involving upregulation of MMPs and breakdown of collagen, and that treatment with an MMP inhibitor may be effective as a treatment strategy for this heart condition.

Left atrial appendage thrombus formation, potential of resolution and association with prognosis in a large real-world cohort

Comprehensive data on factors influencing left atrial appendage (LAA) thrombus formation, resolution and impact on survival are limited. In this single-center, retrospective study 7759 (2010–2015) patients with symptomatic ongoing atrial fibrillation (AF) on admission were screened for LAA thrombi. 450 patients had LAA thrombi. 481 patients without LAA thrombi were randomly selected as controls. We assessed clinical, echocardiographic, laboratory parameters and long-term survival of both groups. Patients with LAA thrombi compared to controls were older, had more strokes, higher CHA2DS2 -VASc scores, worse renal function, less controlled diabetes, advanced heart failure, lower LAA emptying velocities, higher levels of cardiac and inflammatory markers (all p < 0.001). 56.3% of followed-up patients (304) dissolved their LAA thrombi. Chances of thrombus resolution increased with rising LAA flow velocities (OR 1.061, p = 0.022), whereas advanced age (OR 0.950, p < 0.001) and presence of permanent AF (OR 0.354, p < 0.001) decreased chances of thrombus resolution. Presence of LAA thrombi was associated with a markedly reduced 10-year survival probability (31% versus 69%). LAA thrombus formation is promoted by advanced structural heart disease, inflammation, diabetes and impaired renal function. Younger age, non-permanent AF and higher LAA flow velocities were predictors of thrombus resolution. Thrombus formation was associated with poor prognosis.

Electric cardioversion in patients treated with oral anticoagulants: embolic material in the left atrial appendage.

Atrial fibrillation (AF) remains the most common arrhythmia. The sinus rhythm restoration procedure without adequate anticoagulant preparation may lead to a thromboembolic event in approximately 5-7% of patients. The initiation of oral anticoagulation significantly reduces this risk by inhibiting formation of embolic material in the heart cavities, especially in the left atrial appendage (LAA). However, there is a group of patients who develop embolic material in the LAA despite oral anticoagulation treatment. The best treatment method to dissolve thrombus in the LAA is not clear, due to the lack of studies with adequate power and endpoints that can determine the best management strategy. We present clinical trials comparing the efficacy and safety of oral anticoagulants in patients undergoing AF cardioversion. We evaluate the frequency of LAA thrombus formation in patients with AF on treatment with oral anticoagulants. Furthermore, we discuss the effectiveness of various treatment strategies on LAA thrombus resolution.

Abstract 13300: Cardiac Structural and Functional Characteristics Are Associated With Left Atrial Appendage Thrombus Formation in Non-Valvular Atrial Fibrillation

Introduction: Non-valvular 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 CHA2DS2-VASc score that does not account for LAA structural characteristics. Methods: The research comprises a retrospective case-control study of 196 subjects with NVAF who underwent TEE. The control group, without thrombus (n=117), was selected from two different groups, both pools had: NVAF and CHA2DS2-VASc score ≥ 3. One group underwent screening TEE prior to Watchman closure device placement from January 2015 to December 2019 (n=74) the second underwent TEE for any indication from February to October 2014 (n=43). The study group, with thrombus (n=79), included patients with NVAF, a TEE study performed between February 2014 and December 2020, and LAA thrombus. LAA ostial areas (calculated from orthogonal measurements 0, 90° or 45, 135°), maximal depth, and peak outflow velocity were measured, and the rhythm during TEE was interpreted. The control and study groups were compared using Student’s or Welch’s t-test based on variance ratios. Results: Patient characteristics and TEE data were collected (Table 1). Patients in the control group compared to the study group had significantly greater LV EF, LAA exit velocities, LAA ostial areas, and maximal LAA depth, and were more likely to be in sinus rhythm at the time of TEE. There were no significant differences between the groups in overall CHA2DS2-VASc scores. Conclusion: Cardiac structural and functional characteristics are associated with left atrial appendage thrombus among patients with NVAF.

Left ventricular longitudinal contraction impacts the left atrial appendage function and the occurrence of thromboembolic events in patients with atrial fibrillation

Abstract Introduction Previous research has revealed a relationship between left ventricular (LV) function and incidence of stroke in atrial fibrillation (AF) but the mechanism remains unknown. Purpose Given that the left atrial appendage (LAA) is located in the vicinity of the LV base we hypothesized that the LV longitudinal contraction has an impact on the LAA function, LAA thrombus (LAAT) formation, and occurrence of ischemic stroke (Figure 1A). The aim of this study was to investigate this phenomenon using transesophageal echocardiography (TEE). Material and methods We included in our study 105 consecutive patients (age 59±11; 55 men) undergoing TEE-guided cardioversion for AF. LV longitudinal function was assessed using the mitral annulus plane systolic excursion (MAPSE). LAA function was evaluated using the LAA emptying velocity (LAAEV) and LAA ejection fraction (LAAEF) (Figure 1B). The presence LAAT and spontaneous echo contrast (SEC) were evaluated as well. Results Our patients had a median CHADS2vasc score = 3 (IQR 2–4), LVEF=50±11%, and MAPSE=7.3±1.7mm. MAPSE showed a positive significant correlation with both LAAEV (r=0.34; p&amp;lt;0.01) and LAAEF (r=0.23; p&amp;lt;0.05) (Figure 2). LVEF correlated significantly with LAAEV (r=0.42, p&amp;lt;0.01), and LAA area (r=−0.34; p&amp;lt;0.05), respectively. Additionally, patients who exhibited SEC had significantly lower LAAEF as well as LAAEV when compared with patients without SEC: 31±12% vs 38±12% P=0.022 and 35±18cm/s vs 49±21cm/s P=0.005. Patients who displayed both SEC and LAAT had wider LAA neck when compared to the rest of the group (21.46±3.96mm vs. 18.23±3.78mm; P=0.021). Logistic regression analysis revealed that MAPSE independently predicted the occurrence of ischemic stroke both in univariate and multivariate models that also included the CHADSvasc2 score. Conclusions LV longitudinal contraction appears to influence LAA function. This relationship could potentially have an impact on occurrence of thromboembolic events in patients with atrial fibrillation. Funding Acknowledgement Type of funding sources: None.

Stroke risk evaluation for patients with atrial fibrillation: Insights from left atrial appendage.

Left atrial appendage (LAA) is believed to be a common site of thrombus formation in patients with atrial fibrillation (AF). However, the commonly-applied stroke risk stratification model (such as. CHA2DS2-VASc score) does not include any structural or hemodynamic features of LAA. Recent studies have suggested that it is important to incorporate LAA geometrical and hemodynamic features to evaluate the risk of thrombus formation in LAA, which may better delineate the AF patients for anticoagulant administration and prevent strokes. This review focuses on the LAA-related factors that may be associated with thrombus formation and cardioembolic events.

Risk of left atrial appendage thrombus in patients with atrial fibrillation and chronic kidney disease.

BackgroundAtrial fibrillation (AF) and chronic kidney disease (CKD) are associated with an increased risk of ischemic stroke. The aim of this study was to compare the clinical characteristics, the incidence of left atrial appendage (LAA) thrombus and its predictors, and spontaneous echo contrast (SEC) in a population of patients with AF depending on estimated glomerular filtration rate (eGFR) values.MethodsThis study included 1962 patients who underwent transesophageal echocardiographic examination prior to cardioversion or ablation in the years 2014–2018 in three cardiac centers.ResultsMore than a quarter of AF patients had decreased eGFR (< 60 mL/min/1.73 m2) and were characterized as a high-risk population, with more comorbidities, higher thromboembolic and bleeding risk compared to those with normal renal function. Oral anticoagulation (OAC) was prescribed in 97% and 93% of patients with decreased and normal eGFR, respectively, with a higher prevalence of prescribed non-vitamin K antagonist oral anticoagulants (NOACs). The incidence of LAA thrombus (24%, 9% and 4%) and SEC (25%, 25% and 19%) increases simultaneously with a decrease in eGFR (< 30, 30–59 and ≥ 60 mL/min/1.73 m2, respectively). Among patients prescribed reduced doses of NOAC, those with decreased eGFR were more often observed with LAA thrombus (10% vs. 2.5%). Non-paroxysmal AF, heart failure and previous bleeding were predictors of LAA thrombus, irrespective of eGFR value. CKD was the predictor of LAA thrombus in all patients including those with non-paroxysmal AF, males, without diabetes, without hypertension and with CHA2DS2-VASc < 2.ConclusionsDespite OAC, patients with concomitant AF and CKD remain at high risk for LAA thrombus formation.

Characteristics of non-valvular atrial fibrillation with left atrial appendage thrombus who are undergoing appropriate oral anticoagulation therapy.

We investigated the characteristics of patients with non-valvular atrial fibrillation (NVAF) and left atrial (LA) appendage (LAA) thrombus who had been given appropriate oral anticoagulation therapy. We studied 737 NVAF patients who were scheduled for catheter ablation or electrical cardioversion. All patients received appropriate oral anticoagulation therapy for at least 3weeks prior to echocardiography in accordance with the guidelines. Whether LAA thrombus was present or absent on transesophageal echocardiography (TEE) was determined by at least three senior echocardiologists. LAA thrombi were observed in 22 patients (3.0%). Multivariate logistic regression analysis showed that LAA flow and LA volume index were both independent predictors of LAA thrombus formation; however, LAA flow (≤ 18cm/s) was indicated as a more powerful predictor. Moreover, the prevalence of LAA thrombus formation in patients with NVAF without LA enlargement (LA volume index ≤ 34mL/m2) was extremely rare (0.4%). LAA thrombus formation in patients with a mildly dilated LA volume index of 34-49.9mL/m2 and paroxysmal AF was also extremely rare (0.0%). LAA flow is strongly associated with LAA thrombus formation, even in NVAF patients treated with appropriate oral anticoagulation therapy. Augmented oral anticoagulation therapy or transcatheter or surgical LAA closure should be considered for such patients, especially for those with an LAA flow < 18cm/s. Furthermore, TEE for evaluating LAA thrombus before catheter ablation or electrical cardioversion may be unnecessary for NVAF patients who are undergoing appropriate oral anticoagulation therapy, depending on LA size.

Dobutamine-supported WATCHMAN FLX implant in a patient with recurrent left atrial appendage thrombus and spontaneous echo contrast formation

We present a rare case of dobutamine-supported WATCHMAN FLX™ device deployment in a medically complex patient prone to recurrent left atrial appendage thrombus and spontaneous echo contrast formation due to underlying low-flow state.

Left atrial appendage structure predicts thromboembolic risk in 185 patients with crytogenic stroke/TIA without history of AF

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): Akerhus University Hospital Dept. of Cardiology Background Cryptogenic stroke/TIA (CS) is supposed to be associated with intracardiac thrombus formation and left atrial (LA) structure, in particular thrombus formation in left atrial appendage (LAA). However, there is little evidence if thromboembolic risk is associated with LAA morphology in patients with CS. Purpose We aimed to investigate, if different LAA morphology types may predict thromboembolic risk in patients with CS. Methods In this prospective study (mean follow-up 859 ± 226 days), 185 patients with CS (mean age 68 ±13 years, 33% female) without history of AF were included. All patients underwent complete transesophageal echocardiography in sinus rhythm after index CS (mean 5 ± 3days). Occurrence of LAA thrombus, sludge or spontaneous echo contrast (SEC) were defined as thromboembolic risk and LAA structure was evaluated by 2D and 3D transesophageal echocardiography. Multilobate LAA was defined as LAA with &amp;gt; 1 lobes. Results Of the 185 included patients, LAA type chicken wing was found in 79 (43%), type windsock in 64 (35%), type cactus in 35 (19%) and type cauliflower in 7 (4%). Thrombus formation occurred in 29/185 (16%), LAA sludge in 112/185 (61%), and LAA SEC in 74/185 (40%), which is increased compared to data in the general population. We found SEC in sludge in 65/112 (58%), SEC in thrombus in 18/29 (62%) and sludge in thrombus in 27/29 (93%). SEC and sludge were significantly associated with thrombus formation, (p &amp;lt; 0.001 and p &amp;lt; 0.01, respectively). Finally, thromboembolic risk occurred in 123 (67%) of all patients with CS. Moreover, LAA type chicken wing was significantly associated with thromboembolic risk (p &amp;lt; 0.01), while all other LAA types were not. Multilobate LAA occurred in 115 (62%) of all patients and predicted thromboembolic risk vs. non-lobated LAA (p= 0.04). In a multivariate analysis LAA type chicken wing and multilobate LAA were independently predictors of thromboembolic risk, figure 1. Conclusions Patients with cryptogenic stroke/TIA without history of AF showed increased thromboembolic risk, and SEC and sludge were significantly associated with LAA thrombus formation. Only LAA type chicken wing and multilobate LAA predicted independently thromboembolic risk in this study. Abstract Figure.