Left Atrial Appendage Thrombus Research Articles

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.

Left Atrial Appendage Depth and Tachycardia Bradycardia Syndrome as Important Predictors of Left Atrial Appendage Thrombus in Patients with Nonvalvular Atrial Fibrillation.

Background Atrial fibrillation (AF) is the most common heart rhythm disorder that has been shown to be associated with a significant increase in stroke and systemic embolism risk. The left atrial appendage (LAA) is a finger-like extension originating from the left atrium; the formation of thrombus in LAA is the main reason of stroke and systemic embolism in patients with nonvalvular atrial fibrillation (NVAF). This study is aimed at finding out the risk of left atrial appendage thrombus (LAAT) in patients with nonvalvular atrial fibrillation (NVAF). Method We retrospectively examined the clinic and left atrial computer tomography angiography (CTA) features of patients assessed in Zhengzhou No. 7 People's Hospital between January 2020 and January 2021 derivation. Student's t-test, chi-square test, receiver operating characteristics (ROC) curves, and logistic regression analysis were used to identify predictors of LAAT. Result Of 480 patients included in the analysis, LAAT was found in approximately 9.2% of all patients. Univariate demographic predictors of LAAT included left atrium top and bottom diameter (LTD), left atrial appendage depth (LAAD), CHA2DS2-VASc, tachycardia bradycardia syndrome (TBS), and nonparoxysmal atrial fibrillation (PAF). In a multiple logistic regression analysis, the independent predictors of thrombus were LAAD > 23.45 mm (odds ratio: 4.216, 95% CI: 1.869-9.510, P = 0.001), TBS (odds ratio: 4.076, 95% CI: 1.655-10.038, P = 0.002), and non-PAF (odds ratio: 2.896, 95% CI: 1.183-7.094, P = 0.02). Conclusion In NVAF patients with LAAT, evidence suggested that larger LAAD, non-PAF, and TBS present a high risk of LAAT. This is the first report demonstrating that the LAAD and TBS are associated with LAAT in patients with NVAF.

Predictors of Thrombus Dissolution in the Left Atrial Appendage in Patients with Persistent Nonvalvular Atrial Fibrillation

The aim of this study is to identify factors influencing the likelihood of the thrombus dissolution in the left atrial appendage in patients with persistent nonvalvular atrial fibrillation. Material and methods. A repeated transesophageal echocardiography was performed in 88 patients with persistent nonvalvular atrial fibrillation and with the left atrial appendage thrombus at the first transesophageal echocardiography. Results. The second transesophageal echocardiography was performed on average 30.0 (22.0; 40.0) days after the first one, the thrombus dissolution in the left atrial appendage was revealed in 60 (68.2%) patients. The multivariate logistic regression analysis showed that the chances of the thrombus dissolution increased by 5.789 (1.907–17.568) times with the thrombus size not more 25 mm, by 5.318 (1.325–21.353) times with the left atrial appendage emptying flow velocity not less 20 cm/s and 3.687 (1.229–11.059) times when prescribing the direct oral anticoagulants, and not warfarin. Combination of two or more factors give the probability of the thrombus dissolution of more than 89.6%. Conclusion. The probability of the thrombus dissolution in left atrial appendage in patients with persistent nonvalvular atrial fibrillation increases with a small thrombus size, a high the left atrial appendage emptying flow velocity, and if direct oral anticoagulants were prescribed.

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.

Incidence and Predictors of Left Atrial Appendage Thrombus before Catheter Ablation of Thrombogenic Arrhythmias.

Introduction: Transesophageal echocardiography (TEE) is routinely performed before catheter ablation of atrial tachyarrhythmias to rule out the presence of left atrial thrombi. However, data to support this practice are inconsistent. Methods: We analyzed consecutive pre-procedural TEE in a high-volume electrophysiology center for the presence of left atrial thrombi and a relevant flow reduction in the left atrial appendage (LAA) defined as LAA sludge or LAA emptying velocity (LAAEV) < 20 cm/s. The possible predictors of reduced flow were recorded and compared in a multivariate logistic regression analysis. Results: 1676 TEE were included (1122 before pulmonary vein isolation, 436 before atrial flutter ablation, 166 before other ablations). 543 patients (32%) were female and 991 (59%) were on DOAC. Nine patients (0.5%) had an LAA thrombus on pre-procedural TEE. Ninety-five further patients (5.7%) had a relevant reduction in LAA flow. The underlying rhythm showed a significant association with the presence of LAA thrombus or reduced LAA flow (p = 0.003). Patients in sinus rhythm and cavotricuspid isthmus-dependent atrial flutter exhibited the lowest risk. Additionally, reduced kidney function was associated with a reduction in LAA flow velocities (p = 0.04). Of note, two LAA thrombi occurred in patients in sinus rhythm and six out of nine patients with an LAA thrombus were on vitamin-K antagonists. Conclusions: LAA thrombus is a rare occurrence before an elective catheter ablation. The underlying rhythm and kidney function may serve as markers of a higher likelihood of significantly reduced LAAEV and LAA thrombus.

Left atrial thrombus and smoke resolution in patients with atrial fibrillation under chronic oral anticoagulation.

The study aimed to explore the resolution of left atrial and left atrial appendage (LAA) spontaneous echo-contrast or thrombus in patients with nonvalvular atrial fibrillation/flutter (AF/AFL) under chronic oral anticoagulation (OAC). A single-center retrospective analysis of patients who underwent a transesophageal echocardiography (TOE) for an electrical cardioversion was conducted. Among 277 TOE performed, 73 cases (26%) of LAA echo-contrast or thrombus were detected, 53 patients with LAA/LA echo-contrast (19%) and 20 (7%) with a thrombus. All patients were under chronic anticoagulation with a VKA (65%) or with a NOAC (35%). The Echo-contrast Group maintained the same OAC strategy in 49 patients (93%). The Thrombus Group kept the same OAC strategy with a NOAC in 6 cases (30%) and changed the strategy in 14 patients (70%), titrating NOAC dose in 1 (5%) and the VKA dose in 4 (20%) and switching from NOAC to VKA in 5 (25%), from VKA to NOAC in 3 (15%), and from NOAC to NOAC in 1 (5%). Smoke resolution was observed in 4/40 cases (10%) of the smoke group and thrombus resolution in 8/15 (53%) of the thrombus group. Patients with thrombus resolution had a lower CHA2DS2-Vasc score (3.5 ± 2 vs 4 ± 1, p = 0.05), were more often under NOAC (37.5 vs 28%, p = 0.07), and had a longer anticoagulation time (7.5 vs 4months, p = 0.08). Changing OAC strategy is associated with thrombus resolution in more than 50% of chronically anticoagulated patients.

Prevalence and Rate of Resolution of Left Atrial Thrombus in Patients with Non-Valvular Atrial Fibrillation: A Two-Center Retrospective Real-World Study.

Background and aim. Thromboembolic events due to left atrial appendage (LAA) thrombosis are the main complication of non-valvular atrial fibrillation (NVAF). Although anticoagulants are effective in patients with NVAF, a minimal residual thromboembolic risk persists. Little is known about the prevalence of LAA thrombus and the rate of resolution after the recommended period of anticoagulation therapy, including vitamin K antagonists (VKA), heparin, and non-vitamin K antagonist oral anticoagulants (NOACs). Methods and results. We aimed to study the prevalence of LAA thrombus in an unselected cohort of patients undergoing transesophageal echocardiogram (TEE), and the determinants of LAA thrombus resolution. We retrospectively analyzed 8888 consecutive TEEs performed over five years in two high-volume centers and included all patients with LAA thrombus. A total of 265 patients (3%) had an LAA thrombus. Among these, 97% presented with AF. Fifty-eight percent of patients were on anticoagulants at least three weeks before the diagnosis. After the LAA thrombus diagnosis, VKAs were prescribed in 52%, heparin in 18.5%, and NOAC in 27% of patients. Among the 183 patients with repeat TEE, performed at (25–75th) 39 days (21–84), 67% showed resolution of the LAA thrombus. Although the rate of thrombus resolution was higher in patients treated with NOACs (NOACs 71%, VKA 66%, Heparin 60%) the difference between anticoagulants was statistically non-significant (VKA, OR 0.9, p = 0.83; NOAC, OR 1.23, p = 0.42; heparin, OR 0.69, p = 0.35). Thus, NOACs were demonstrated to be at least as effective as other anticoagulants in the rate of LAA thrombus resolution. Upon multivariate-adjusted analysis, higher LAA emptying velocities were the only predictor of thrombus resolution. In conclusion, the majority of patients were already on anticoagulants. NOACs could be at least as effective as other anticoagulants, yielding an LAA thrombus resolution in two-thirds of patients. This may have clinical relevance, especially in patients undergoing cardioversion or catheter ablation.

Incidence and predictors of left atrial appendage thrombus on transesophageal echocardiography before elective cardioversion

Guidelines recommend transesophageal echocardiography (TEE) before cardioversion in thrombogenic arrhythmias when the requirement of ≥ 3 weeks of anticoagulation is not met. Current data to support this approach, especially with direct oral anticoagulants (DOAC), are scarce. We analyzed consecutive elective pre-cardioversion TEE in a high-volume electrophysiology center for the occurrence of left atrial appendage (LAA) thrombi or reduced LAA flow velocity. Possible predictors were recorded and compared in a multivariate logistic regression analysis. Consecutive pre-cardioversion TEE in 512 patients (148 female, median age 69 years) were included. In all patients, indication for TEE was either intake of anticoagulation < 3 weeks before cardioversion or uncertain adherence to the prescribed anticoagulation regimen. Of the 512 TEE, 19 (3.7%) depicted a LAA thrombus. An additional 41 patients (8.0%) showed either a reduced LAA flow velocity (≤ 20 cm/s), LAA sludge, or both. In a multivariate logistic regression analysis, QRS width on admission 12-lead ECG emerged as a possible predictor of LAA thrombus and reduced LAA flow (p = 0.008). Noteworthy, a high CHA2DS2-VASc score was not associated with an increased risk of reduced LAA emptying velocity and LAA thrombi were even found in patients with a CHA2DS2-VASc score of 0 (n = 1) and 1 (n = 1). The presence of LAA thrombus before an elective cardioversion is a rare event in the age of direct oral anticoagulants. However, LAA thrombi occurred even in supposed low-risk individuals according to the CHA2DS2-VASc score. QRS width may aid in identifying patients at risk of reduced LAA flow velocity.

Residual stroke risk after left atrial appendage closure in patients with prior oral anticoagulation failure

BackgroundPatients with atrial fibrillation (AF) and oral anticoagulation (OAC) failure may benefit from left atrial appendage closure (LAAC), however, the evidence is scarce. We report outcomes of LAAC in patients with OAC failure compared to those with classic indications of OAC contraindications. MethodsProspective registry of LAAC with Amplatzer or WATCHMAN device followed by dual antiplatelet therapy (DAPT) was analyzed (05.2014–11.2019). The study group included patients with OAC failure defined as stroke/TIA/PE/LAA thrombus (n = 39) during OAC, whereas the control group consisted of patients with OAC contraindications (n = 156). Structured follow-up at 3, 6, and 12 months was done. ResultsThe study group compared to controls was younger [73 (IQR, 62–77) vs 74 (IQR, 68–81) years, P = 0.046], with higher CHA2DS2-VASc [5.0 (IQR, 3.0–6.0) vs 4.0 (IQR, 3.0–5.0), P = 0.001)], lower HAS-BLED [2.0 (IQR, 1.0–3.0) vs 3.0 (IQR, 2.0–3.0), P = 0.006] and similar proportion of WATCHMAN implantations (43.6% vs 44.2%, P = 1.000). The reduction from CHA2DS2-VASc predicted to observed annual stroke/TIA/PE rate was markedly smaller in the study vs control group (14% vs 77%) with 10.3% vs 1.9% stroke/TIA/PE respectively (P = 0.031). The reduction from HAS-BLED predicted to observed annual major nonprocedural bleeding rate was higher (100% vs 7.4%) with 0.0% vs 5.1% major bleedings respectively (P = 0.361). The device-related thrombosis remained similar (13.2% vs 11.3%, P = 0.778). ConclusionsPatients after LAAC for OAC failure and unremarkable prior bleeding history presented with high residual stroke and low bleeding risks. Therefore concomitant long-term OAC or prolonged DAPT should strongly be considered in this population.

Left atrial appendage thrombus in patients referred for electrical cardioversion for atrial fibrillation: a prospective single‑center study.

Left atrial appendage thrombus (LAAT) is a risk factor for stroke; however, the actual health risk associated with LAAT in patients with atrial fibrillation (AF) on chronic anticoagulation is unknown. We aimed to assess the prevalence and predictors of LAAT, and its predictive role in relation to mortality, stroke, and systemic thromboembolic events among consecutive AF patients on oral anticoagulation (OAC) admitted for electrical cardioversion. This was a prospective, single‑ center cohort study. The participants underwent transesophageal echocardiography before electrical cardioversion. A total of 296 patients were enrolled. The primary outcome was the presence of LAAT. All participants were followed for 12 months to evaluate the incidence of systemic thromboembolic events, stroke, and death. Despite uninterrupted OAC in patients with AF of above 48-hour duration scheduled for cardio-version, we found a high prevalence of LAAT, reaching 14.5%. There was no difference in the prevalence of thrombi between different types of OAC (P = 0.26). The independent predictors of LAAT were chronic obstructive pulmonary disease, heart failure, prior myocardial infarction, greater left atrial diameter, lower left ventricular ejection fraction, higher CHA2DS2‑VASc score, and reduced dabigatran dose. The optimal cutoff values for the prediction of LAAT were the age of at least 74 years, left atrial diameter equal or greater than 52 mm, left ventricular ejection fraction equal or lower than 40%, and CHA2DS2‑VASc score equal or greater than 3. No strokes or systemic thromboembolic events occurred over the follow‑up period. The presence of LAAT had no practical value for predicting stroke, thromboembolic events, or death in patients with AF and on chronic anticoagulation.

Assessment of LAA strain and thrombus mobility and its impact on thrombus resolution - value of a novel echocardiographic thrombus tracking method

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): FCT – Fundação para a Ciência e Tecnologia Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER) Background The left atrial appendage (LAA) is the major nidus for thrombus in patients with non-valvular atrial fibrillation. LAA thrombus mobility and changes hereof under anticoagulation may serve as a marker of both risk of embolism and efficacy of treatment. In this study, we hypothesized that LAA dynamics and thrombus mobility could serve as a baseline marker of thrombus dissolvability. Methods Transesophageal echocardiographic (TEE) images of in whom LAA thrombi were previously diagnosed were evaluated. Each image was tracked using a state-of-the-art tracking toolbox and functional information from the LAA and thrombi extracted. Global LAA motion was quantified through the longitudinal strain, while thrombus mobility was measured through a novel tracking scheme by directly capturing and measuring the thrombus motion isolated from the global cardiac motion. Baseline characteristics and echocardiographic parameters were compared between responders (thrombus resolution, i.e. no thrombus found at follow-up TEE) and non-responders (thrombus persistence or growth, i.e. thrombus found at follow up TEE) groups. Results 35 patients (54.3% male and 45.7% female) with a mean age of 72.9 ± 14.1 years were included. Atrial fibrillation was present in all patients, showing a high risk for thromboembolism (CHA2DS2-VASc-Score 4.1 ± 1.5). Moderately reduced LVEF (41.7 ± 14.4%) and signs of diastolic dysfunction (E/E’ = 19.7 ± 8.5) was found in the cohort. While anticoagulation was initiated in all patients, resolution was achieved in 51.4% of patients. Significantly higher thrombus mobility (0.33 ± 0.13mm vs. 0.18 ± 0.08mm, p &amp;lt; 0.01 – Figure 1A) and LAA peak strain (-3.0 ± 1.3 vs -1.6 ± 1.5%, p &amp;lt; 0.01 – Figure 1B) were observed in responders against the non-responders group. Conclusions The quantification of the thrombus mobility through a tracking scheme is feasible. In our study population, higher thrombus mobility appeared to be associated with thrombus resolution. Further studies are required to evaluate the additional prognostic of the proposed technique. Figure 1 – Quantification of the thrombus mobility (A) and peak LAA longitudinal strain (B) in both responder (blue) and non-responder group (green). *p &amp;lt; 0.05, unpaired t-test between non-responder and responder groups. Abstract Figure 1

Accidental diagnosis of significant coronary artery disease by cardiac CT scan to rule out left atrial appendage thrombus in patients with atrial fibrillation during COVID19 pandemic

Abstract Funding Acknowledgements Type of funding sources: None. Introduction The exclusion of left atrial appendage (LAA) thrombus prior to urgent electrical cardioversion (DCCV) for atrial fibrillation (AF) is traditionally performed by transesophageal echocardiography (TEE). During the COVID19 pandemic, TEE was replaced by cardiac CT (CCT) due to its high aerosol generating property, which in addition to assessing the anatomy of the heart, can also be used to evaluate the coronary arteries at the same time. Methods In our retrospective study, we evaluated the cardiac CT scans of patients undergoing DCCV in our institution between January 1, 2020 and February 28, 2021 for coronary artery disease (CAD). The scans were performed by a GE Revolution 256-slice CT scanner. Results CCT scans were performed in 32 patients to rule out LAA thrombus (24 male; 8 female; age: 61.8 ± 11.2 years; BMI: 29.2 ± 4.4; heart rate: 79.2 ± 24.4 1/min; CHA2DS2VASc score: 2.4 ± 1.5). The mean radiation exposure of the scans was DLP: 356.3 ± 130.1 mGy-cm; effective dose: 5.0 ±1.8 mSv, Ca-score: 361.4 ± 883.0. In 4 equivocal cases TEE was also performed with negative results. No CAD was confirmed in 7 cases, mild CAD in 14 patients. CCT was not diagnostic only in 4 cases. Significant (moderate or severe) CAD was detected in 7 cases, invasive coronary angiography (ICA) was also performed in 5 cases. In 2 cases significant one-vessel disease, in 2 other cases borderline (FFR: 0.81 and 0.84) stenosis and in 1 case only mild CAD was diagnosed by ICA. Conclusions CCT scans performed by our 256-slice CT scanner for AF can identify patients, who require further invasive or invasive and functional coronary artery assessment with satisfactory accuracy. In terms of coronary artery disease, the non-diagnostic scan rate was low, despite the presence of arrhythmia, suboptimal heart rate and higher than usual Ca-score.

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.

Percutaneous closure of atrial appendage with thrombus - a strategy shift? Report of a case series

Abstract Funding Acknowledgements Type of funding sources: None. Background. Percutaneous closure of left atrial appendage (LAAO) is a recent preventive modality in atrial fibrillation. (AF) However, presence of thrombus which is a strong stroke risk multiplier represented a standard contraindication to purely percutaneous approach. Aim. To test the safety and feasibility of LAAO in patients (pts) with appendage blood stasis and distal thrombus. Methods. Using a novel generation transvascular device allowing "shallow dive" implantation we tested the feasibility of LAAO in pts with appendage blood stasis and distal thrombus. Additionally, hybrid transvascular approach with arch protection device was also tested. Indications included development of heart failure in AF or recurrent cerebral events in pts with LAA thrombi. Results. We successfully performed 3 procedures in pts (2F, 1M, age 73-76) with distal LAA thrombus confirmed in 3D TEE / CT. After 3D echocardiographic sizing omitting appendage angiogram, occluder was implanted from right femoral venous access via septal puncture. In 2 patients right radial access was additionally used to introduce commercially available arch protection device. In all cases the occluder did not engage distal appendage zone and was appropriately deployed. However in patients with arch protection 1-2 mm debris was captured by protection device. No neurological sequelae were noted. Conclusion. Our initial experience documents safety and feasibility of percutaneous LAAO in presence of appendage blood stasis and distal thrombus based on 3DE sizing and novel genertaion device with optional percutaneous aortic arch protection. The long term efficacy of such unorthodox has yet to be determined in the setting of severely prothrombotic milieu, abnormal left ventricular function but with potential for risk reduction or even reopening options of cardioversion. Abstract Figure. Occlusion of LAA appendage with thrombus

A preliminary study of the safety and effectiveness of isoproterenol loading transesophageal echocardiography in atrial fibrillation

Abstract Funding Acknowledgements Type of funding sources: None. Background In patients with sludge or severe spontaneous echo contrast (SEC) in the left atrial appendage (LAA), isoproterenol loading transesophageal echocardiography (ISP-TEE) has been reported to check the presence of thrombus in the LAA, as the sludge or severe SEC disappears (Figure 1). Purpose The aim of this study was to assess the safety of ISP-TEE for the identification of LAA thrombus and the hemodynamic changes in the LAA caused by ISP loading. Methods We prospectively enrolled 25 patients with atrial fibrillation (AF) and sludge or SEC in the LAA who underwent ISP-TEE from April 2020 to July 2021. ISP was administered intravenously to achieve the target heart rate (HR) defined as follows: Max HR [beats per minutes: bpm] = 220 – age (years), Target HR [bpm] = Max HR × 0.8. Patients with tachycardia exceeding Max HR before ISP administration, hemodynamic instability, and other contraindications to ISP were excluded from the study. To assess the safety of ISP-TEE, we evaluated patients’ condition, changes in systolic blood pressure (sBP) and HR before and after ISP loading. We also assessed the presence or absence of worsening heart failure, new arrhythmias other than atrial fibrillation, and cerebral infarction or transient ischemic attack during the examination, and after 24 hours. Hemodynamic evaluation was performed using LAA blood flow velocity, LAA tissue Doppler imaging (TDI) velocity, and LAA volume fraction (LAAVF) defined as follows: LAAVF (%) = (Max LAA volume – Min LAA volume) / Max LAA volume × 100. Quantification of LAA volume was performed using the stacked-contour method of a 3-dimensional TEE full-volume acquisition. Results Among 25 patients, 13 patients had sludge or grade3 SEC, 7 patients had grade2 SEC, 5 patients had grade1 SEC. HR after ISP loading was significantly higher than before loading, but sBP did not change significantly before and after ISP loading. No complications due to ISP loading were observed during examination and after 24 hours. After ISP loading, there were 18 patients with grade 1 SEC or no SEC (classified as Group1), 7 patients had residual sludge or grade 2 to 3 SEC (classified as Group2). The differences in LAA blood flow velocity between before and after ISP loading was faster in Group1 than in Group2: 13.0 ± 10.5 vs 2.6 ± 4.2. p = 0.019. The differences in TDI velocity was also faster in Group1 than in Group2: 1.46 ± 1.14 vs 0.19 ± 0.50, p = 0.010. The differences in LAAVF was higher in Group1 than in Group2: 13.7 ± 10.3 vs 2.2 ± 2.0, p = 0.009. Conclusions In our study, no complications were observed in ISP-TEE for the identification of LAA thrombus. Patients with grade 1 SEC or no SEC, the LAA function was increased by ISP loading. These results may provide insights into the mechanisms of ISP loading on SEC in the LAA. Abstract Figure.

Association between left atrial appendage fibrosis and thrombus formation: A histological approach.

Although recent echocardiographic studies have suggested that left atrial appendage (LAA) remodeling contributes to the development of LAA thrombus (LAAT), histological evidence is absent. The objective of this study was to examine clinical parameters and histological findings to clarify the factors involved in LAAT formation. A total of 64 patients (no atrial fibrillation [AF], N = 22; paroxysmal AF, N = 16; nonparoxysmal AF, N = 26) who underwent LAA excision during surgery were enrolled. Transthoracic and transesophageal echocardiography were performed before surgery. We evaluated the fibrosis burden (%) in the excised LAA sections with Azan-Mallory staining in patients with a LAAT compared with those without. Patients with paroxysmal and non-paroxysmal AF had a higher LAA fibrosis burden than those without AF (p = .005 and p < .0001, respectively). Among the patients enrolled, 16 had a LAAT and 15 of them had nonparoxysmal AF. Among the nonparoxysmal AF patients, those with a LAAT had significantly higher LAA fibrosis burden than those without (23.8% [14.8%-40.3%] vs. 12.8% [7.4%-18.2%], p = .004) and echocardiographic parameters of the left atrial volume index (R = 0.543, p = .01), LAA depth (R = 0.452, p = .02), and LAA flow velocity (R = - 0.487, p = .01) were correlated with the LAA fibrosis burden. This study provided histological evidence that LAA fibrosis is related to LAAT formation. Echocardiographic parameters of LAA remodeling and function were correlated with the LAA fibrosis burden.

Left Atrial Appendage Thrombus in Patients with Nonvalvular Atrial Fibrillation before Catheter Ablation and Cardioversion: Risk Factors beyond the CHA2DS2-VASc Score.

Left atrial appendage thrombus (LAAT) is a surrogate of thromboembolic events in patients with nonvalvular atrial fibrillation (NVAF). We aimed to investigate the risk factors for LAAT formation before catheter ablation and cardioversion beside the CHA2DS2-VASc score. In this case-control study, patients with NVAF who underwent transesophageal echocardiography (TEE) were included. Demographic data, laboratory results, and echocardiographic measurements were retrospectively collected. Logistic regression analysis was performed to determine risk factors predicting LAAT. Of the 543 included patients, LAAT was identified in 50 patients (9.2%). Multivariable logistic regression analysis for the entire cohort showed that NT-proBNP (per 500 ng/L increase, OR (95% CI): 1.09 (1.00–1.19), p = 0.038) and LDL-C (per 1 mmol/L increase, OR (95% CI): 1.70 (1.05–2.77), p = 0.032) were independently correlated with the presence of LAAT after the adjustment for CHA2DS2-VASc score and anticoagulant therapy. The subgroup analysis of patients without anticoagulant therapy also yielded similar results. Regarding patients with CHA2DS2-VASc scores ≤ 1, a higher level of LDL-C (per 1 mmol/L increase, OR (95% CI): 6.31 (2.38–16.74), p < 0.001) independently correlated with the presence of LAAT. The present study suggests that beyond CHA2DS2-VASc score, raised NT-proBNP and LDL-C are additional predictors for LAAT in NVAF patients.

Generalizable Framework for Atrial Volume Estimation for Cardiac CT Images Using Deep Learning With Quality Control Assessment.

ObjectivesCardiac computed tomography (CCT) is a common pre-operative imaging modality to evaluate pulmonary vein anatomy and left atrial appendage thrombus in patients undergoing catheter ablation (CA) for atrial fibrillation (AF). These images also allow for full volumetric left atrium (LA) measurement for recurrence risk stratification, as larger LA volume (LAV) is associated with higher recurrence rates. Our objective is to apply deep learning (DL) techniques to fully automate the computation of LAV and assess the quality of the computed LAV values.MethodsUsing a dataset of 85,477 CCT images from 337 patients, we proposed a framework that consists of several processes that perform a combination of tasks including the selection of images with LA from all other images using a ResNet50 classification model, the segmentation of images with LA using a UNet image segmentation model, the assessment of the quality of the image segmentation task, the estimation of LAV, and quality control (QC) assessment.ResultsOverall, the proposed LAV estimation framework achieved accuracies of 98% (precision, recall, and F1 score metrics) in the image classification task, 88.5% (mean dice score) in the image segmentation task, 82% (mean dice score) in the segmentation quality prediction task, and R2 (the coefficient of determination) value of 0.968 in the volume estimation task. It correctly identified 9 out of 10 poor LAV estimations from a total of 337 patients as poor-quality estimates.ConclusionsWe proposed a generalizable framework that consists of DL models and computational methods for LAV estimation. The framework provides an efficient and robust strategy for QC assessment of the accuracy for DL-based image segmentation and volume estimation tasks, allowing high-throughput extraction of reproducible LAV measurements to be possible.

Atrial fibrillation and stroke: importance of left atrium as assessed by echocardiography.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, which has been increasing dramatically. AF has unfavorable consequences, such as stroke, heart failure, and cardiovascular death. Of these, stroke has been considered to be the serious complication. Recently, direct oral anticoagulation or new technologies, such as the WATCHMAN left atrium (LA) appendage closure device, have emerged to prevent stroke. Therefore, the accurate estimation of thromboembolic risk and appropriate prevention are essential for high-risk patients with AF. Although CHADS2 and CHA2DS2-VASc scores has been widely used to predict the risk of stroke in patients with AF, some researchers showed that there was no relationship between CHADS2 and CHA2DS2-VASc scores and LA appendage thrombus formation. Recent studies have reported that combination of echocardiographic parameters to CHADS2 or CHA2DS2-VASc scores can stratify high risk groups for LA appendage thrombus formation and onset of stroke. In this review, we focus on the epidemiological, pathophysiological, and prognostic associations between AF and stroke, and review the clinical and echocardiographic predictors for stroke in patients with AF.

Risk Prediction for Left Atrial Appendage Thrombus in Patients With AF

Exclusion of left atrial appendage thrombus (LAAT) by transoesophageal echocardiography (TOE) is recommended in patients with inadequate anticoagulation prior to direct cardioversion (DCR) or catheter ablation for atrial fibrillation/flutter (AF/AFL). LAAT risk factors in this population remain poorly defined.