Impact of Left Atrial Appendage Flow Velocity on Thrombus Resolution and Clinical Outcomes in Patients with Atrial Fibrillation and Silent Left Atrial Thrombi: Insights from the LAT Study

AIMS

Blood stasis is crucial in developing left atrial (LA) thrombi. LA appendage peak flow velocity (LAAFV) is a quantitative parameter for estimating thromboembolic risk. However, its impact on LA thrombus resolution and clinical outcomes remains unclear.

METHODS AND RESULTS

The LAT study was a multicenter observational study investigating patients with atrial fibrillation (AF) and silent LA thrombi detected by transesophageal echocardiography (TEE). Among 17,436 TEE procedures for patients with AF, 297 patients (1.7%) had silent LA thrombi. Excluding patients without follow-up examinations, we enrolled 169 whose baseline LAAFV was available. Oral anticoagulation use increased from 85.7% at baseline to 97.0% at the final follow-up (p < 0.001). During 1-year, LA thrombus resolution was confirmed in 130 (76.9%) patients within 76 (34-138) days. Conversely, 26 had residual LA thrombi, 8 had thromboembolisms, and 5 required surgical removal. These patients with failed thrombus resolution had lower baseline LAAFV than those with successful resolution (18.0 [15.8-22.0] vs. 22.2 [17.0-35.0], p = 0.003). Despite limited predictive power (area under the curve, 0.659; p = 0.001), LAAFV ≤20.0 cm/s (best cutoff) significantly predicted failed LA thrombus resolution, even after adjusting for potential confounders (odds ratio, 2.72; 95% confidence interval, 1.22-6.09; p = 0.015). The incidence of adverse outcomes including ischemic stroke/systemic embolism, major bleeding, or all-cause death was significantly higher in patients with reduced LAAFV than in those with preserved LAAFV (28.4% vs. 11.6%, log-rank p = 0.005).

CONCLUSIONS

Failed LA thrombus resolution was not rare in patients with AF and silent LA thrombi. Reduced LAAFV was associated with failed LA thrombus resolution and adverse clinical outcomes.

Can transesophageal echocardiography be safely omitted in patients scheduled for elective ablation of atrial arrhythmias? Data based on the LATTEE registry

BACKGROUND

According to the present guidelines, transesophageal echocardiography (TEE) before scheduled catheter ablation (CA) for atrial arrhythmias (atrial fibrillation [AF] or atrial flutter [AFL]) is not deemed obligatory for optimally anticoagulated patients. However, daily clinical practice significantly differs from the recommendations.

AIMS

That study aimed to identify transthoracic echocardiographic parameters that could be useful in revealing patients without left atrial thrombus (LAT), thereby contributing to avoiding unnecessary TEE before scheduled CA.

METHODS

This is a sub-analysis of a multicenter, prospective, observational study - LATTEE registry. A total of 1346 patients referred for TEE before scheduled CA of AF/AFL were included.

RESULTS

LAT was present in 44 patients (3.3%) and absent in the remaining 1302, who were younger, more likely to have paroxysmal AF, and displayed sinus rhythm during TEE. Additionally, they exhibited a lower incidence heart failure, diabetes, systemic connective tissue disease, and chronic obstructive pulmonary disease. Furthermore, they had a lower CHA2DS2-VASc score and a higher prevalence of direct oral anticoagulants. Echocardiographic parameters, including left ventricular ejection fraction (LVEF) > 65%, left atrial diameter (LAD) < 40 mm, left atrial area (LAA) < 20 cm2, left atrial volume (LAV) < 113 ml, and left atrial volume index (LAVI) < 51 ml/m2, demonstrated 100% sensitivity and 100% negative predictive value for the LAT absence, and weremet by 417 patients. Additional echocardiographic indices: LVEF/LAD > 1.4, LVEF/LAVI > 1.6 and LVEF/LAA > 2.7 identified an additional 57 patients, bringing the total predicted LAT-free patients to 474 (35%).

CONCLUSIONS

Simple echocardiographic parameters could help identify individuals for whom TEE could be safely omitted before scheduled for elective CA due to atrial arrhythmias.

Large Left Atrial Thrombus in a Patient With Severe Mitral Stenosis and Atrial Fibrillation Despite Anticoagulant Therapy: A Case Report

This case report highlights a patient with atrial fibrillation, severe mitral stenosis, and left atrial dilatation who developed a large thrombus, despite being on anticoagulant therapy. The complexity of thrombus formation in patients with multiple risk factors is described, emphasising the need for regular echocardiographic assessments to detect and monitor thrombi, even in patients undergoing anticoagulant treatment. The interplay between atrial fibrillation, mitral stenosis, and left atrial dilatation contributes to thrombus formation, requiring a multidisciplinary approach to the management of these patients. Further research is needed to improve our understanding of the optimal treatment strategies for such cases. Timely identification and intervention are critical to mitigate the risk of thromboembolic complications in these high-risk patients.

Rivaroxaban Failure Presenting With Renal Infarction in a Patient With Persistent Atrial Fibrillation: A Case Report

Direct oral anticoagulants (DOAC) are the preferred choice of anticoagulation for patients with atrial fibrillation. DOACs are always preferred over vitamin K antagonists due to their better safety profile in terms of life-threatening bleeding and decreased need for INR (international normalised ratio) monitoring. Although the most commonly used anticoagulation, failure to DOAC has been reported. Here we present a rare case of rivaroxaban failure presenting with left renal infarction in a patient who had dense spontaneous echocardiographic contrast in the left atrium visualised by transthoracic echocardiography.

Thrombectomy using AlphaVac for left atrial thrombus causing mechanical mitral valve obstruction and cardiogenic shock

We present a 73-year-old female with history of rheumatic heart disease status post-mechanical mitral valve on warfarin, valvular atrial fibrillation, and alpha thalassemia who was admitted to an outside hospital with anterior ST-segment myocardial infarction. Coronary angiogram showed occluded left anterior descending artery (LAD) with acute thrombus status post-thrombectomy and balloon angioplasty.

Serum Fibrinogen and Renal Dysfunction as Important Predictors of Left Atrial Thrombosis in Patients with Atrial Fibrillation

BACKGROUND

As has been shown previously, patients with atrial fibrillation (AF) who have left atrial thrombus (LAT) also have elevated plasma concentrations of fibrinogen. In this study, we tried to determine if this is the consequence of a genetic trait and whether elevated concentrations of fibrinogen could be used to predict LAT in patients with AF.

METHODS

We recruited 181 consecutive patients scheduled for pulmonary vein isolation (PVI) or direct current cardioversion. The primary endpoint was the presence of LAT on transesophageal echocardiography (TOE). We recorded routine clinical and biochemical data as well as the polymorphism type of the fibrinogen gene for the β chain. To control potentially interfering variables, we performed propensity score matching (PSM). Multivariable and univariable logistic regression models (LRM) were computed using the CHA2DS2-Vasc score, the fibrinogen concentration and creatinine clearance as estimated by the Cockcroft-Gault equation.

RESULTS

60 of 181 patients had LAT as detected by TOE. As expected, patients with LAT had significantly higher concentrations of fibrinogen (3.9 vs. 3.6 g/L); p = 0.01 in the unadjusted analysis. After performing PSM, there were no statistically significant differences between the groups, except for creatinine clearance (79.9 vs. 96.8 mL/min); p = 0.01. There were also no differences regarding the -455 G/A βfibrinogen polymorphism distribution between the two groups. After constructing the LRM, we found no performance enhancement for the CHA2DS2-Vasc score by adding the fibrinogen concentration or creatinine clearance alone, but when all three variables were put together, there was a significant improvement in LAT prediction (AUC 0.64 vs. 0.72), p = 0.026.

CONCLUSION

Our study found no evidence of elevated levels of circulating fibrinogen in patients with LAT or a connection between those levels and the A/A and A positive polymorphism. When used together with renal function markers such as creatinine clearance, plasma fibrinogen concentrations can provide additional power to the CHA2DS2-Vasc score for predicting LAT.

Left Atrial Thrombus in the Setting of Mitral Stenosis

A 56-year-old man with no significant past medical history presented with exertional shortness of breath. Echocardiogram, cardiac magnetic resonance, and computed tomography showed mitral stenosis and a left atrial thrombus. Left atrial thrombus formation is a well-known complication of severe mitral stenosis that can lead to systemic thromboembolism. The patient underwent mitral valve replacement, left atrial thrombus resection, and left atrial appendage closure that resulted in significant improvement in breathing.

Use of a new non-contrast-enhanced BOOST cardiac MR sequence before electrical cardioversion or ablation of atrial fibrillation-a pilot study

Introduction

Left atrial appendage (LAA) thrombus is the most common source of embolization in atrial fibrillation (AF). Transesophageal echocardiography (TEE) is the gold standard method for LAA thrombus exclusion. Our pilot study aimed to compare the efficacy of a new non-contrast-enhanced cardiac magnetic resonance (CMR) sequence (BOOST) with TEE for the detection of LAA thrombus and to evaluate the usefulness of BOOST images for planning radiofrequency catheter ablation (RFCA) compared with left atrial (LA) contrast-enhanced computed tomography (CT). We also attempted to assess the patients' subjective experiences with TEE and CMR.

Methods

Patients with AF undergoing either electrical cardioversion or RFCA were enrolled. Participants underwent pre-procedural TEE and CMR scans to evaluate LAA thrombus status and pulmonary vein anatomy. Patient experiences with TEE and CMR were assessed using a questionnaire developed by our team. Some patients scheduled for RFCA also had pre-procedural LA contrast-enhanced CT. In such cases, the operating physician was asked to subjectively define the quality of the CT and CMR scan on a scale of 1-10 (1 = worst, 10 = best) and comment on CMR's usefulness in RFCA planning.

Results

Seventy-one patients were enrolled. In 94.4%, both TEE and CMR excluded, and in 1 patient, both modalities reported the presence of LAA thrombus. In 1 patient, TEE was inconclusive, but CMR excluded LAA thrombus. In 2 patients, CMR could not exclude the presence of thrombus, but in 1 of those cases, TEE was also indecisive. During TEE, 67%, during CMR, only 1.9% of patients reported pain (p < 0.0001), and 89% would prefer CMR in case of a repeat examination. The quality of the left atrial contrast-enhanced CT scans was better compared with the image quality of the CMR BOOST sequence [8 (7-9) vs. 6 (5-7), p < 0.0001]. Still, the CMR images were useful for procedural planning in 91% of cases.

Conclusion

The new CMR BOOST sequence provides appropriate image quality for ablation planning. The sequence might be useful for excluding larger LAA thrombi; however, its accuracy in detecting smaller thrombi is limited. Most patients preferred CMR over TEE in this indication.

Clinical Features Associated with 'Normal Range' Fibrin D-Dimer Levels in Atrial Fibrillation Patients with Left Atrial Thrombus

BACKGROUND

Left atrial thrombus (LAT) often complicates with atrial fibrillation (AF). The evidence whether fibrin D-dimer levels could be used as a predictive biomarker for LAT is contradictory. This study firstly investigated the relationship between 'normal range' D-dimer and prevalent LAT. Second, we explored factors contributing to normal D-dimer levels in the presence of LAT.

METHODS

We studied 244 AF patients with LAT (mean age: 59.9 years, SD:11.7; 53.3% female): of these, 103 (42.2%) had normal D-dimer, 25 (10.2%) had atrial thrombus exclusion score (ATE score) of 0 19 (16.7%) males had CHA₂DS₂-VASc score of 0, 21(16.2%) females had CHA₂DS₂-VASc score of 1 and 16 had overlapped ATE score of 0 and CHA₂DS₂-VASc score of 0 (N = 8 if male) or CHA₂DS₂-VASc score of 1(N = 8 if female). Using multivariate binary analysis, larger left atrial diameter (LAD; adjusted OR: 1.06, 1.03-1.10, p = 0.001) were associated with increased D-dimer. Patients with high body mass index (BMI), hypertension history and previous anticoagulation were more likely to show normal range D-dimer levels in the presence of LAT.

CONCLUSIONS

A high prevalence (42.2%) of 'normal range' D-dimer levels was found in AF patients with LAT, especially in those with hypertension, high BMI and prior anticoagulation. D-dimer levels of those patients with larger LAD were more likely to be increased.

Utilization of Two- and Three-Dimensional Transesophageal Echocardiography in Successfully Guiding Transcatheter Mitral Valve in Bioprosthetic Mitral Valve/Mitral Ring Implantation without Complications in Patients with Thrombus in Left Atrium/Left Atrial Appendage

BACKGROUND

The aim of this study is to describe, for the first time to our knowledge, the utilization of both two-dimensional (2D) and three-dimensional (3D) transesophageal echocardiography (TEE) in successfully performing transcatheter mitral valve (MV) in bioprosthetic MV/MV annulopasty ring implantation using the apical approach in 12 patients (pts) with co-existing left atrial appendage (LAA) and/or LA (left atrium) body thrombus, which is considered a contraindication for this procedure.

METHODS AND RESULTS

All pts were severely symptomatic with severe bioprosthetic MV stenosis/regurgitation except one with a previous MV annuloplasty ring and severe native MV stenosis. Thrombus in LAA and/or LA body was noted in all by 2D and 3DTEE. All were at high/prohibitive risk for redo operation and all refused surgery. Utilizing both 2D and 3DTEE, especially 3DTEE, guidewires and the prosthesis deployment system could be manipulated under direct vision into the LA avoiding any contact with the thrombus. The procedure was successful in all with amelioration of symptoms and no embolic or other complications over a mean follow-up of 21 months.

CONCLUSION

Our study demonstrates the feasibility of successfully performing this procedure in pts with thrombus in LAA and/or LA body without any complications.

Risk factors for left atrial thrombus in younger patients (aged < 65 years) with atrial fibrillation or atrial flutter: Data from the multicenter left atrial thrombus on transesophageal echocardiography (LATTEE) registry

Background

Methods

Results

Conclusions

Increased Body Mass Index and Risk of Left Atrial Thrombus in Nonvalvular Atrial Fibrillation Patients-Data from the Left Atrial Thrombus on Transesophageal Echocardiography (LATTEE) Registry

An increased body mass index (BMI) is associated with a higher incidence of atrial fibrillation (AF) and a higher risk of thromboembolic complications in AF patients. The aim of this study was to investigate the effect of BMI on the risk of left atrial thrombi (LATs) in patients with nonvalvular AF/atrial flutter (AFl) (NV AF/AFl). Patients diagnosed with NVAF/AFl (between November 2018 and May 2020) were selected from the multicenter, prospective, observational Left Atrial Thrombus on Transesophageal Echocardiography (LATTEE) registry that included AF/AFl patients referred for cardioversion or ablation followed by transesophageal echocardiography. A total of 2816 AF/AFl patients (63.6% males; mean age 65.8 years; mean BMI 29.8 kg/m2) were included in the study. Two hundred and twenty-two of them (7.9%) had LATs. Compared with normal-weight patients, those with BMIs ≥ 25 kg/m2 more frequently presented clinical factors potentially provoking LATs, such as non-paroxysmal AF/AFl (p = 0.04), hypertension (p < 0.001), and diabetes (p < 0.001); had higher CHA2DS2 scores (p < 0.001); and had larger LA dimensions (LA diameter and LA area) (p < 0.001 for both parameters). On the other hand, they showed some features negatively related to thromboembolic risk; for example, they were younger (p < 0.001) and were more often male (p = 0.002). In addition, patients with abnormal BMIs were more likely to be smokers (p = 0.006) and to be treated with oral anticoagulants (p = 0.005). Despite these differences in the prevalence of thromboembolic risk factors, the incidence of LATs was not increased in patients with abnormal body weight (overweight and obese compared to normal-weight patients) in this large real-life cohort of AF/AFl patients. This is probably due to the balanced composition regarding the prevalence of positive and negative thromboembolic risk factors.

Left Ventricular Ejection Fraction Can Predict Atrial Thrombosis Even in Non-High-Risk Individuals with Atrial Fibrillation

Background—Current guidelines do not recommend routine use of transesophageal echocardiography (TOE) in anticoagulated patients with atrial fibrillation (AF). The aim of our study was to identify predictors for left atrial thrombosis (LAT) in patients with AF that would require TOE despite anticoagulation therapy, using clinical, laboratory and echocardiographic data which are usually obtained in those patients in a real-world setting. Methods—We analyzed data from electronic medical records (EMR) of consecutive AF patients referred to two university hospitals between January 2014 and December 2017 for pulmonary vein isolation (PVI) or direct current cardioversion. The primary endpoint was the presence of left atrial thrombus on TOE. Multivariable and univariable logistic regression models were computed using variables that were significantly different between the LAT and the control groups. Results—A total of 838 patients were included, of whom 132 (15.8%) had LAT. After controlling for other variables, only the left ventricle ejection fraction (LVEF) remained statistically significant with an OR of 0.956 (95% CI 0.934−0.979), p < 0.01. Regression models including LVEF had significantly higher areas under the receiver operating characteristic (ROC) curves, including in subgroups with non-high thromboembolic risk (CHA2DS2-Vasc = 0 or 1), with an area under the curve (AUC) of 0.76 (95% CI 0.71−0.81), p < 0.0001. Conclusions—The LVEF is an independent predictor of LAT, and it might improve thromboembolic risk stratification in future models. LVEF significantly increased the predictive value of the CHA2DS2-Vasc model and was able to identify LAT in non-high-risk patients.

Left Atrial Thrombus in Patients With Non-valvular Atrial Fibrillation: A Cross-Sectional Study in China

Background

Stroke is predominately attributed to left atrial thrombus (LAT) in patients with non-valvular atrial fibrillation (NVAF), however, its detection rate in real clinical practice has been few reported in China.

Objective

This study aimed to investigate the prevalence and associated factors of LAT in patients with NVAF in China.

Methods

All adult NVAF patients undergoing transesophageal echocardiography (TEE) in the China Atrial Fibrillation Center database from January 2017 to January 2022 were enrolled in this study. The prevalence of LAT was calculated, and associated factors were identified.

Results

A total of 36,007 NVAF inpatients from 602 hospitals in 30 provinces/autonomous regions/municipalities were included in the final analysis, with a median age of 66 years and 39.4% were female. LAT was present in 1,467 (4.1%) patients overall, 2.7, 5.7, and 6.8% in patients with paroxysmal, persistent, and long-standing persistent AF, respectively. In subgroup analysis, including age ≥ 65 years, CHA2DS2-VASC score ≥ 2, left atrial diameter (LAD) ≥ 50 mm, left ventricular ejection fraction (LVEF) < 50%, and anticoagulation, patients with paroxysmal AF always had the lowest LAT prevalence, followed by patients with persistent and long-standing persistent AF. Patients treated with anticoagulants had less prevalent LAT than those without anticoagulation (2.1 vs. 5.0%, p < 0.001). In multivariate analysis, AF pattern (both persistent AF and long-standing persistent AF), hypertension, chronic heart failure, coronary heart disease, transient ischemic attack/stroke, diabetes mellitus, and LAD (per 5 mm) were associated with an increased prevalence of LAT. However, LVEF (per 5%) and anticoagulation were associated with a reduced prevalence of LAT.

Conclusion

LAT was found in 4.1% of Chinese adult NVAF inpatients underwent TEE in real-world experience. The prevalence of LAT mainly associated with non-paroxysmal AF, cardiovascular diseases, diabetes mellitus, enlarged left atrium, lower LVEF, and lack of anticoagulation therapy.

Percutaneous balloon mitral valvuloplasty using veno-arterial loop and neuro-embolic protection for mitral stenosis with thrombus

Percutaneous balloon mitral valvuloplasty (PBMV) is not traditionally suitable for patients with mitral stenosis (MS) and left atrium (LA) thrombus. Moreover, PBMV cannot be performed in patients with LA thrombus not resolving after anti-coagulation treatment. Here we present a case of PBMV using a novel technique employing both a veno-arterial loop and neuro-embolic protection, in a patient with MS and LA thrombus resistant to warfarin therapy. The patient successfully underwent PBMV without any complications.

Refinement of CHADS2 and CHA2DS2-VASc scores predict left atrial thrombus or spontaneous echo contrast in nonvalvular atrial fibrillation patients

Objective

To investigate the risk factors of left atrial thrombus (LAT)/spontaneous echo contrast (SEC) in patients with nonvalvular atrial fibrillation (AF).

Methods

This retrospective study analysed the data from consecutive patients with nonvalvular AF that underwent transoesophageal echocardiography. Logistic regression analysis was performed to identify risk factors of LAT/SEC. Receiver operating characteristic curve analysis was undertaken compare the new scales with CHADS2 and CHA2DS2-VASc scores.

Results

A total of 558 patients with AF were included in the study. LAT/SEC was detected in 137 (24.6%) patients. The independent risk factors of LAT/SEC beyond CHADS2 or CHA2DS2-VASc scores included non-paroxysmal AF and left atrial diameter >37.5 mm. These two variables were added into the CHADS2 or CHA2DS2-VASc score to build new scales. Areas under the curve for the new scales based on CHADS2 and CHA2DS2-VASc scores were significantly higher than the CHADS2 or CHA2DS2-VASc score both in the overall study cohort and in patients at a high risk of thromboembolism.

Conclusions

Non-paroxysmal AF and increased left atrial diameter beyond the CHADS2 or CHA2DS2-VASc score were independent risk factors of LAT/SEC and may help to improve the current risk stratification, especially for patients with nonvalvular AF at a high risk of thromboembolism.

A Ping Pong Thrombus in the Left Atrium

In this illustrative case, a transesophageal echocardiographic examination in a 69-year-old woman revealed normally functioning mechanical mitral prosthesis and a 4 cm left atrial heterogenous thrombus moving around her left atrium like a ping pong ball. Also visible was a thrombus within the left atrial appendage; the left atrial thrombus moved toward the mitral orifice and was bounced away by the mitral regurgitant jet.

Nomogram to Predict Left Atrial Thrombus or Spontaneous Echo Contrast in Patients With Non-valvular Atrial Fibrillation

Background: The predictive power of the CHADS₂ and CHA₂DS₂-VASc scores for the presence of Left atrial thrombus (LAT)/ spontaneous echo contrast (SEC) in non-valvular atrial fibrillation (NVAF) is modest. The aim of this analysis is to define clinical and ultrasonic variables associated with LAT/SEC and to propose nomograms for individual risk prediction.

Methods: Data on 1,813 consecutive NVAF patients who underwent transesophageal echocardiography (TEE) from January 2016 to January 2021 were collected. The univariate and multivariate logistic regression analyses were used to construct a nomogram. We examined the predictive ability of the risk scores by calculating the area under the curve (AUC). Moreover, the performance of the nomogram was assessed with respect to calibration, discrimination, and clinical usefulness.

Results: LAT/SEC was found in 260 (21.0%) and 124 (21.6%) patients in the training and validation cohorts, respectively. On multivariate analysis, independent factors for LAT/SEC were Age, left atrial diameter (LAD), left ventricular ejection fraction (LVEF), hypertension (HTN), previous stroke or transient ischemic attack, Non-paroxysmal AF and a nomogram was built based on these variables. The calibration curve for the probability of LAT/SEC showed good prediction agreement with actual observation. The nomogram achieved good concordance indexes of 0.836 and 0.794 in predicting LAT/SEC in the training and validation cohorts, respectively. Decision curve analysis demonstrated that the nomogram would be clinically useful.

Conclusions: In this study, a nomogram was constructed that incorporated six characteristics of NVAF patients. The nomogram may be of great value for the prediction of LAT/SEC in NVAF patients.

Effect of Mitral Regurgitation on Systemic Coagulation Activity in Rheumatic Heart Disease as Assessed by D-dimer Levels

Introduction

Atrial fibrillation and mitral stenosis, especially in combination, increase the risk of left atrial thrombus formation and systemic embolization. However, whether severe mitral regurgitation (MR) improves systemic hypercoagulable state in these patients is unclear. remains unclear. The study aims to study the impact of severe MR on systemic coagulation by the use of D-dimer levels.

Methods

It was a prospective, cross-sectional study done on 400 subjects consisting of 350 cases and 50 controls. The cases were divided into seven groups on basis of valvular pathology, rhythm, and presence of a clot. The D-dimer level was compared in all the subgroups.

Result

The mean age of the study population was 32.32±7.30 years with a 48% male population. The highest level of D-dimer was found in patients with thrombus (1.71 ± 1.74 µg/ml). Patients with mitral stenosis had significantly higher plasma D-dimer levels than the control group (p <0.001) while regardless of rhythm, patients with MR had a D-dimer level similar to the control group in sinus rhythm.

Conclusion

Severe MR reduces plasma D-dimer levels to control levels reflecting the protective effect against thrombus formation and systemic embolization.

Prevalence of Left Atrial Thrombus in Anticoagulated Patients With Atrial Fibrillation

BACKGROUND

The prevalence of left atrial (LA) thrombus in patients with atrial fibrillation (AF) or atrial flutter (AFL) on guideline-directed anticoagulation is not well known, yet this may inform transesophageal echocardiogram (TEE) use before cardioversion or catheter ablation.

OBJECTIVES

The purpose of this study was to quantify LA thrombus prevalence among patients with AF/AFL on guideline-directed anticoagulation and to identify high-risk subgroups.

METHODS

EMBASE, MEDLINE, and CENTRAL were systematically searched from inception to July 2020 for studies reporting on LA thrombus prevalence among patients with AF/AFL undergoing TEE following at least 3 weeks of continuous therapeutic oral anticoagulation with vitamin K antagonists (VKAs) or direct oral anticoagulants (DOACs). Meta-analysis was performed using random effects models.

RESULTS

Thirty-five studies describing 14,653 patients were identified. The mean-weighted LA thrombus prevalence was 2.73% (95% confidence interval [CI]: 1.95% to 3.80%). LA thrombus prevalence was similar for VKA- and DOAC-treated patients (2.80%; 95% CI: 1.86% to 4.21% vs. 3.12%; 95% CI: 1.92% to 5.03%; p = 0.674). Patients with nonparoxysmal AF/AFL had a 4-fold higher LA thrombus prevalence compared with paroxysmal patients (4.81%; 95% CI: 3.35% to 6.86% vs. 1.03%; 95% CI: 0.52% to 2.03%; p < 0.001). LA thrombus prevalence was higher among patients undergoing cardioversion versus ablation (5.55%; 95% CI: 3.15% to 9.58% vs. 1.65%; 95% CI: 1.07% to 2.53%; p < 0.001). Patients with CHA₂DS₂-VASc scores ≥3 had a higher LA thrombus prevalence compared with patients with scores ≤2 (6.31%; 95% CI: 3.72% to 10.49% vs. 1.06%; 95% CI: 0.45% to 2.49%; p < 0.001).

CONCLUSIONS

LA thrombus prevalence is high in subgroups of anticoagulated patients with AF/AFL, who may benefit from routine pre-procedural TEE use before cardioversion or catheter ablation.

Atrial Thrombus and Embolic Stroke in a Patient With Surgical Appendage Ligation and Maze Procedure

This case illustrates the incomplete protection of surgical ligation of left atrial appendage and maze procedure at the time of mitral valve replacement against thromboembolic complications and recurrence of atrial fibrillation. The utility of surgical left atrial appendage ligation as stroke prophylaxis and identification of selected high-risk subjects are reviewed. (Level of Difficulty: Intermediate.)

Safety of catheter ablation of atrial fibrillation without pre- or peri-procedural imaging for the detection of left atrial thrombus in the era of uninterrupted anticoagulation

BACKGROUND

The need for pre- or peri-procedural imaging to rule out the presence of left atrial thrombus in patients undergoing catheter ablation of atrial fibrillation (AF) is unclear in the era of uninterrupted direct oral anticoagulant (DOAC) regimen. We sought to examine the safety of catheter ablation in appropriately selected patients with paroxysmal AF without performing screening for left atrial thrombus.

PATIENTS AND METHODS

Consecutive patients planned for radiofrequency AF catheter ablation between January 2016 and June 2020 were enrolled, and prospectively studied. All subjects were receiving uninterrupted anticoagulation with DOACs for at least 4 weeks before the procedure. All subjects were in sinus rhythm the day of the procedure. The primary outcome of the study was ischemic stroke or transient ischemic attack (TIA) during at 30 days.

RESULTS

A total of 451 patients (age 59.7 ± 10.2 years, 289 males) with paroxysmal AF were included in the study. The mean CHA2DS2-VASc score was 1.4 ± 1.2. The mean left ventricular ejection fraction and left atrial diameter were 60 ± 5% and 39.3 ± 4 mm, respectively. Regarding the anticoagulation regimen, apixaban was used in 197 (43.6%) patients, rivaroxaban in 148 (32.8%) patients, and dabigatran in 106 (23.5%) patients. None of the patients developed clinical ischemic stroke or TIA during the 30-day post-discharged period.

CONCLUSIONS

Catheter ablation can be safely performed in low-risk patients with paroxysmal AF without imaging for the detection of left atrial thrombus in the era of uninterrupted DOAC anticoagulation.

Genetic and Clinical Predictors of Left Atrial Thrombus: A Single Center Case-Control Study

Left atrial (LA) thrombus formation is the presumed origin of thromboembolic complications in patients with atrial fibrillation (AF). Beyond clinical risk factors, the factors causing formation of LA thrombi are not well known. In this case-control study, we analyzed clinical characteristics and genetic thrombophilia markers (factor V Leiden (FVL), prothrombin G20210A (FIIV), Tyr2561 variant of von Willebrand factor (VWF-V)) in 42 patients with AF and LA thrombus (LAT) and in 68 control patients with AF without LAT (CTR). Patients with LAT had more clinical conditions predisposing to stroke (mean CHA2DS2-VASc-score 3.4 ± 1.5 vs. 1.9 ± 1.4; P < 0.001), a higher LA volume (96 ± 32 vs. 76 ± 21 ml, P = 0.002) and lower LA appendage emptying velocity (0.21 ± 0.11vs. 0.43 ± 0.19 m/s, P < 0.001). Prevalence of FVL, FIIV and VWF-V mutations was not different, but in the subgroup of patients <65 years (y) there was a tendency for a higher incidence of VWF-V with a prevalence of 27% (LAT <65 y) vs. 7% (CTR <65 y, P = 0.066). These findings warrant further investigation of the VWF-V as a risk factor for LA thrombogenesis in younger patients.

Acute Mesenteric Ischemia With Secondary Thromboembolism: A Rare Complication

Acute mesenteric ischemia presents a clinical challenge due to its subtle presentation and high mortality rate, which can mimic a variety of other conditions. Acute mesenteric ischemia requires a high index of suspicion, especially in those with comorbidities and risk factors such as hypertension, diabetes, atrial fibrillation, and peripheral arterial disease. The inciting thrombus commonly originates in the left atrial appendage or left atrium, embolizing to occlude mesenteric vessels, with resulting gut ischemia. Patients commonly present with post-prandial abdominal pain as mesenteric vascular demands increase, though diarrhea and gastrointestinal bleeding may be the presenting symptom. CT angiography of the abdomen and pelvis provides rapid confirmation of the diagnosis and visualization of the thrombus, aiding vascular surgical management. The authors present a novel case of a 69-year-old female with an acute mesenteric ischemia of her superior mesenteric artery and a second acute arterial thromboembolism to the right axillary artery visualized from her left atrial appendage.

[Surgical considerations for two patients with cardioembolic stroke and mobile thrombus in the left atrium appendage]

Two men (Case 1, 74 years old; Case 2, 65 years old) developed cardioembolic stroke due to self-interruption of anticoagulants for treating atrial fibrillation. They both had mobile thrombus in the left atrial appendage. In Case 1, a left atrial thrombectomy was scheduled on day 8, but infarction re-occurred on the morning of the the surgery, producing neurological sequelae. In Case 2, left atrial thrombectomy and left atrial appendage closure were performed successfully on day 8. The indication and timing of cardiac thrombectomy after the onset of cerebral infarction have not been standardized, and they seem to differ among individuals. Therefore, in the future, the optimal timing of left atrial thrombectomy should be decided based on the size and morphology of the left atrial thrombus, the size of the cerebral infarction and the presence or absence of hemorrhagic infarction.

The Frequency of Left Atrial Thrombus on Transthoracic Echocardiogram in Patients with Mitral Stenosis

Background

Patients with mitral stenosis (MS) are more prone to develop left atrial (LA) thrombus. This cross-sectional study was conducted to determine the frequency of LA thrombus on transthoracic echocardiography (TTE) in patients with MS.

Methods

In this study, we included patients diagnosed with MS undergoing TTE at the echocardiography department of the National Institute of Cardiovascular Disease (NICVD), Karachi, Pakistan. The severity of MS was classified based on the mitral valve area (MVA) as follows: very severe: MVA of ≤1.0 cm²; severe: MVA of ≤1.5 cm²; and mild to moderate: MVA of >1.5 cm². The LA thrombus was observed and noted on TTE.

Results

A total of 256 MS patients were included in this study, out of which 46.5% (119) were male. The mean age was 33.78 ±11.51 years. MS was classified as mild to moderate in 3.5% of the patients, severe in 54.3%, and very severe in 42.2%. In 98.8% of the patients, the etiology of MS was rheumatic. LA thrombus was observed in 25% (64) of the patients and LA smoke was observed in 12.1% (31). Among other findings, mitral regurgitation (MR) was observed in 17.2% of the patients, aortic regurgitation (AR) in 5.1%, aortic stenosis (AS) in 4.7%, and tricuspid regurgitation (TR) in 48.8%. Five (2%) patients had atrial septal defect (ASD), 17.3% had left ventricular (LV) dysfunction, 15.2% had right ventricular (RV) dysfunction, and vegetation was seen in 11.8% of the patients. Patients with LA thrombus were found to be associated with the following conditions on a higher scale compared to those without: decreased ejection fraction (EF) (52 ±8.5% vs. 54.94 ±6.6%; p: 0.011); RV dysfunction (39.1% vs. 7.3%; p: <0.001); and presence of associated pathologies (82.8% vs. 43.8%; p: <0.001).

Conclusion

LA thrombus on TTE was detected in a significant number (25%) of patients with MS. It was also found to be strongly associated with the severity of the disease, reduced EF, RV dysfunction, and the presence of associated value pathologies.

Animal model of left atrial thrombus in congestive heart failure in rats

The aim of the present study was to develop and study a new model of left atrial thrombus (LAT) in rat with congestive heart failure (CHF). CHF was induced by aortic banding for 2 mo, followed by ischemia-reperfusion (I/R) and subsequent aortic debanding for 1 mo. Cardiac function and the presence of LAT were assessed by echocardiography. Masson's staining was performed for histological analysis. All CHF rats presented with significantly decreased cardiac function, fibrosis in remote myocardium, and pulmonary edema. The incidence rate of LAT was 18.8% in the rats. LAT was associated with severity of aortic constriction, aortic pressure gradient, aortic blood flow velocity, and pulmonary edema but not myocardial infarction or a degree of left ventricular depression. The progressive process of thrombogenesis was characterized by myocyte hypertrophy, fibrosis, and inflammation in the left atrial wall. Fibrin adhesion and clot formation were observed, whereas most LAT presented as a relatively hard "mass," likely attributable to significant fibrosis in the middle and outer layers. Some LAT mass showed focal necrosis as well as fibrin bulging. Most LAT occurred at the upper anterior wall of the left atrial appendage. Aortic debanding had no significant impact on large LATs (>5 mm2) that had formed, whereas small LATs (<5 mm2) regressed 1 mo after aortic release. LAT is found in a rat model of aortic banding plus I/R followed by aortic debanding. The model provides a platform to study molecular mechanisms and potential new pathways for LAT treatment. NEW & NOTEWORTHY It is critically important to have a rodent model to study the molecular mechanism of thrombogenesis in the left atrium. Left atrial thrombus (LAT) is not a simple fibrin clot like those seen in peripheral veins or arteries. Rather, LAT is a cellular mass that likely develops in conjunction with blood clotting. Studying this phenomenon will help us understand congestive heart failure and promote new therapies for LAT.

The use of cardiac-CT alone to exclude left atrial thrombus before atrial fibrillation ablation: Efficiency, safety, and cost analysis

BACKGROUND

Atrial fibrillation (AF) is a growing financial burden on the healthcare system. Cardiac computed tomographic angiography (CCTA) is needed for pulmonary vein mapping before AF ablation (AFA). CCTA has shown to be an alternative to transesophageal echocardiogram (TEE) to rule out left atrial appendage thrombus (LAAT) pre-AFA. We aim to examine the safety, cost-effectiveness, and time-efficiency of utilizing CCTA alone to rule out LAAT before AFA.

METHODS

We prospectively screened patients with paroxysmal AF undergoing cryoablation. CCTA with delayed enhancement was performed within 72 hours of AFA. Once LAAT was ruled out, patients were enrolled and planned TEE was cancelled. A retrospective control cohort that had both CCTA and TEE prior to AFA was identified. Direct cost data, electrophysiology laboratory utilization time, and 30-day stroke outcomes were collected from the EMR, follow-up phone calls, or clinic visits, and comparative analyses were performed.

RESULTS

Seventy patients met the inclusion criteria in the prospective CCTA-only cohort, and 71 for the retrospective CCTA+TEE cohort. Baseline characteristics were similar between the two groups. There was a nonsignificant reduction in overall cost ($15,870 ± 1,710 vs $16,557 ± 2,508, P = 0.06) in CCTA-only cohort, whereas the electrophysiology laboratory utilization time was significantly reduced (241.6 ± 41.7 vs 181.3 ±36.4 minutes, P < 0.001). There were no strokes reported on 30-day follow-up in the CCTA-only group.

CONCLUSIONS

In low-to-intermediate stroke risk patients with paroxysmal AF undergoing cryoablation, eliminating TEE and employing CCTA-only strategy to rule-out LAAT improves electrophysiology laboratory efficiency without influencing periprocedural cost or increasing postprocedural stroke risk.

Tumor Or Thrombus? The Role Of Cardiac Magnetic Resonance Imaging In Differentiating Left Atrial Mass In a Transplanted Heart: A Case Report

An unknown mass in the left atrium can be challenging to differentiate, especially after previous heart transplant. A precise diagnosis is clinically crucial because of the therapeutic implications. CMR is a useful, non-invasive tool to distinguish intra-cardiac lesions, thereby enabling clinicians to initiate adequate therapy.

Beating-heart Thoracoscopic Left Atrial Appendage Exclusion in a Patient with Left atrial Thrombus

Stroke remains a major complication of atrial fibrillation and third leading cause of death in Western Countries. [1] While Coumadin and novel oral anticoagulants have been efficient in reducing the stoke risk in patients with atrial fibrillation; there is a subset of patients who are not candidates for anticoagulation.[2] The management of these patients is clinical challenge.We describe a patient with history of permanent atrial fibrillation with contra-indication to anticoagulation presenting with and left atrial thrombus. She was treated with novel generation of epicardial left atrial appendage exclusion device.

Multidetector computed tomography for detecting left atrial/left atrial appendage thrombus: a meta-analysis

BACKGROUND

The diagnostic accuracy of multidetector computed tomography (MDCT) in the detection of left atrial/left atrial appendage (LA/LAA) thrombus had been tested in many studies; however, the results are controversial.

AIM

The aim of the present study was to evaluate synthetically the diagnostic accuracy of MDCT in LA/LAA thrombus.

METHODS

PubMed and Embase were searched for published prospective studies which compared computed tomography with transoesophageal echocardiography (TEE) in detecting LA/LAA thrombus prior to March 2014. Descriptive and quantitative information was extracted and MetaDiSc 1.4 was used to perform a meta-analysis.

RESULTS

Fifteen prospective clinical controlled trials with 2540 patients fulfilled the inclusion criteria. The pooled sensitivities (SEN): 0.957; pooled specificities (SPE): 0.917; pooled positive likelihood ratio (PLR): 22.017; pooled negative likelihood ratio (NLR): 0.060; pooled diagnostic odds ratio (DOR): 437.43; the area under the curve (AUC): 0.9883; Q*-value: 0.9544. However, in the abovementioned indexes, the heterogeneities were statistically significant between studies (P < 0.05, inconsistency index (I(2) ) > 50%). In a sub-analysis of studies in which delayed imaging, electrocardiogram (ECG) gating and heart rate control were performed, not only the diagnostic accuracy, but also the heterogeneities were significantly improved (pooled SEN 0.991; pooled SPE 0.989; pooled PLR 60.768; pooled NLR 0.034; pooled DOR 2561.7; AUC 0.9972; Q*-value 0.9806; all the indexes' P-value were greater than 0.05 and the I(2) were 0%, except for SPE, I(2) = 54.6%).

CONCLUSION

For patients with TEE intolerance or contraindications, MDCT may be an alternative method, especially when the delayed imaging, ECG gating and heart rate control were performed.

A systematic review and meta-analysis of the literature

We performed a meta-analysis about the prevalence of left atrial thrombus (LAT) in patients with atrial fibrillation (AF) undergoing trans-esophageal echocardiography (TEE). Studies reporting on LAT presence in AF patients were systematically searched in the PubMed, Web of Science, Scopus and EMBASE databases and the pooled LAT prevalence was evaluated as weighted mean prevalence (WMP). Seventy-two studies (20,516 AF patients) showed a LAT WMP of 9.8 % (95 %CI: 7.6 %-12.5 %). LAT presence was associated with a higher age (mean difference: 2.56, 95 %CI: 1.49-3.62), and higher prevalence of female gender (OR: 1.35, 95 %CI: 1.04-1.75), hypertension (OR: 1.78, 95 %CI: 1.38-2.30), diabetes mellitus (OR: 1.86, 95 %CI: 1.33-2.59) and chronic heart failure (OR: 3.67, 95 %CI: 2.40-5.60). Overall, LAT patients exhibited a higher CHADS2-score (mean difference 0.88, 95 %CI: 0.68-1.07) and a higher risk of stroke/systemic embolism (OR: 3.53, 95 %CI: 2.24-5.56) compared with those without LAT. A meta-regression showed an inverse association between LAT prevalence and the presence of anticoagulation (Z-value: -7.3, p< 0.001). Indeed, studies in which 100 % of patients received oral anticoagulation reported a 3.4 % WMP of LAT (95 %CI: 1.3 %-8.7 %), whereas studies in which 0 % of patients received anticoagulation showed a LAT WMP of 7.4 % (95 %CI: 2.3 %-21.5 %). Our data suggest that LAT is present in ≍10 % of AF patients, and is associated with a 3.5-fold increased risk of stroke/systemic embolism. Interestingly, LAT is also reported in some of patients receiving anticoagulation. The implementation of the screening of LAT in AF patients before cardioversion/ablation could be useful for the prevention of vascular events.

Thrombus in the left atrial septal pouch mimicking myxoma

A 15 × 13 mm mobile ovoid mass attached via a 15 × 5 mm stalk to the interatrial septum in the left atrium was detected on transesophageal echocardiography and was diagnosed as a myxoma in a 70-year-old woman with chronic atrial fibrillation. She was prescribed anticoagulant therapy with warfarin before elective cardiac surgery and demonstrated no thromboembolic event during a 2.5-month period. Preoperative transesophageal echocardiography showed the disappearance of the intracardiac mass and the presence of a left atrial septal pouch, suggesting that the initial image was a thrombus originating from the left atrial septal pouch.

Computed tomography for detecting left atrial thrombus: a meta-analysis

INTRODUCTION

Thromboembolism, usually originating from the left atrium (LA) and left atrial appendage (LAA), is a major complication of atrial fibrillation and may result in transient ischemic attack and stroke. Computed tomography (CT) is a noninvasive test for detection of LA and LAA thrombus. We sought to conduct a meta-analysis to evaluate the accuracy of CT in detecting LA/LAA thrombus.

MATERIAL AND METHODS

The PubMed, Medline, ISI Web of Knowledge and Cochrane Library databases up to June 2012 were searched for studies comparing CT and transesophageal echocardiography as the reference standard in detecting LA/LAA thrombus. Meta-analysis methods were used to pool sensitivity and specificity and to construct summary receiver operating characteristic (SROC) curves.

RESULTS

A total of 9 studies with 1646 patients were included in this meta-analysis. The publication years spanned from 2007 to 2012. For CT diagnosis of LA/LAA thrombus, the mean sensitivity and specificity were 81% (95% CI: 70-90%) and 90% (95% CI: 88-91%), respectively. The SROC analysis showed an area under the curve of 0.93.

CONCLUSIONS

Computed tomography shows a good diagnostic accuracy in detecting LA/LAA thrombus with high sensitivity and specificity. Thus CT should be considered the foremost noninvasive alternative to transesophageal echocardiography for detecting LA/LAA thrombus. Randomized studies at the patient level are needed to address the potential use of CT in detecting LA/LAA thrombus.

Highly mobile pedunculated left atrial appendage thrombus falling into the mitral valve orifice

We treated two patients with atrial fibrillation and stringlike left atrial appendage thrombus: a 66 year-old man who had apical hypertrophic cardiomyopathy and a 86 year-old woman with no underlying heart disease. In the patient with hypertrophic cardiomyopathy, transesophageal echocardiography showed a highly mobile stringlike echo protruding from the left atrial appendage and sometimes falling into the mitral orifice. Pathologic examination after excision proved the stringlike echo to be a pedunculated structure composed of red and white thrombi. Excision of thrombus was also planned for the woman, who had a history of recurrent cerebral embolism. Because her cerebral CT showed infarction with bleeding, however, surgery was postponed. The stringlike mobile thrombus was not detected by transesophageal echocardiography 1 month later, when a new embolic episode affected a foot. Clinical outcomes of these two patients differed remarkably. The critical findings by transesophageal echocardiography which facilitated differential diagnosis from cardiac tumors were: spontaneous contrast echo accompanying mural thrombuslike echo, and low flow velocity in the left atrial appendage. However, the differential diagnosis may be quite difficult in cases of tumors associated with atrial fibrillation.