Incidence Of Left Atrial Appendage Thrombus Research Articles

How the trabeculae protrude within the left atrial appendage is the key factor affecting thrombosis in patients with atrial fibrillation.

The left atrial appendage (LAA) is a major site of thrombosis in patients with non-valvular atrial fibrillation. The myocardial trabeculae within the LAA have a peculiar tendency to protrude but its relationship to thrombosis remains unknown. This study aimed to investigate the relationship between the condition of trabeculae protrusion and LAA thrombosis. This retrospective study consecutively selected patients diagnosed with non-valvular atrial fibrillation and prepared for radiofrequency ablation from January 2011 to May 2020. Patients were divided into the thrombus group (n = 43), the sludge group (n = 35), and the normal group (n = 407) according to whether the thrombus or sludge was present. The trabeculae protruding angle (TPA), which was measured by the CT scans, was used to quantify the trabeculae protrusion condition. Patients' clinical data, TPA, LAA emptying velocity, and other factors were collected and compared among the three groups. A total of 485 patients were enrolled. The range of TPA was between 0 and 158 degrees, with an average of 89.3 ± 35.6 degrees. The TPA was significantly greater in the thrombus (109.3 ± 14.8 degrees) and sludge groups (110.8 ± 12.8 degrees) than in the normal group (85.3 ± 37.1). The incidence of LAA thrombus and sludge increased with increasing TPA. Multivariate regression analysis showed that the TPA was an independent risk factor for LAA thrombus (OR = 1.046, 95%CI: 1.020-1.073, p < 0.001) and sludge (OR = 1.035, 95%CI: 1.017-1.053, p < 0.001). Further analysis revealed that the TPA was negatively correlated with LAA emptying velocity but its effect on promoting thrombosis was not only mediated by slowing down the flow velocity. The TPA can well reflect the condition of trabeculae protrusion. This study revealed that the TPA was an independent risk factor for LAA thrombus or sludge, providing a potential indicator for future thrombosis risk assessment.

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.

Prevalence and risk factors of left atrial thrombus in patients with atrial fibrillation and lower class (IIa) recommendation to anticoagulants

Oral anticoagulation therapy (OAT) prevents ischaemic incidents in patients with atrial fibrillation (AF). CHA2DS2-VASc risk score of ≥2 points in men and ≥3 in women is a class I indication for OAT. OAT should also be considered as a prevention of thromboembolism in AF men with a CHA2DS2-VASc score of 1 point and women with 2 points, but the class of recommendation is lower (IIa). This study aims to assess the occurrence of left atrial appendage thrombus (LAAT) and risk factors of its formation in patients with lower class recommendation to oral antiocoagulation treatment. The study group consisted of 1,858 patients: 555 patients with class IIa indication to OAT (IIa group) and 1,303 patients with class I indication as a control group (I group). Patients were admitted to three cardiology departments. All subjects underwent transoesophageal echocardiography. The incidence of LAAT was comparable in both IIa and I group: LAAT was confirmed in 30 (5.4%) subjects of IIa group and in 77 (5.9%) of I group. The prevalence of LAAT in IIa group was higher on treatment with VKAs (in comparison to NOACs) (8.4% vs. 3.4%, P=0.010), and lower in case of paroxysmal AF (in comparison to non-paroxysmal AF) (2.4% vs. 9.8%, P=0.0002). Multivariate logistic regression revealed the following variables as the independent predictors of LAAT in IIa group: treatment with VKAs (OR 2.99, 95% CI: 1.33-6.69; P=0.007), paroxysmal AF (OR 0.26, 95% CI: 0.11-0.62; P=0.002) and eGFR <60 mL/min/1.73 m2 (OR 3.19, 95% CI: 1.42-7.16; P=0.005). The prevalence of LAAT in AF patients with lower class (IIa) recommendation to anticoagulants was comparable to higher (I). Treatment with VKAs, along with non-paroxysmal type of AF and eGFR <60 mL/min/1.72 m2 were identified as the strongest predictors of LAAT in IIa group.

Incidence and Predictors of Intracardiac Thrombus on Pre-electrophysiological Procedure Transesophageal Echocardiography

BackgroundCerebral thromboembolism is a potentially devastating complication of atrial fibrillation (AF) and atrial flutter (AFl). The use of transesophageal echocardiogram (TEE) before electrophysiological procedures in anticoagulated patients is variable. Our objective was to determine the incidence and identify predictors of intracardiac left atrial appendage (LAA) thrombus on TEE in patients with AF/AFl before electrical cardioversion or ablation.MethodsWe reviewed TEEs of 401 patients undergoing an electrical cardioversion, AF, or AFl ablation from April 2013 to September 2015 at the McGill University Health Center. Clinical and echocardiographic variables were collected at the time of the TEE and follow-up visits. Multivariate logistic regression was used to determine predictors of LAA thrombus.ResultsOf 401 patients, 11.2% had LAA thrombus on TEE. The majority (87%) of patients were anticoagulated for at least 3 weeks before the TEE. The incidence of LAA thrombus was 21% (23/110) in patients taking warfarin vs 6.4% (15/236) in patients taking direct oral anticoagulants. Multivariate analysis identified prior stroke (odds ratio [OR], 2.7; 95% confidence interval [CI], 1.1-6.9) and heart failure (OR, 2.2; 95% CI, 1.0-4.7) as predictors of thrombus, whereas direct oral anticoagulant use (OR, 0.4; 95% CI, 0.2-0.8) was associated with reduced odds of thrombus.ConclusionsLAA thrombus was identified in a significant proportion of patients undergoing TEE before cardioversion or ablation of AF/AFl despite preprocedural anticoagulation. Patients at increased risk of LAA thrombus (heart failure and prior stroke) may benefit from TEE before cardioversion, AF, or AFl ablation.

Renin-angiotensin system inhibition is associated with reduced risk of left atrial appendage thrombosis formation in patients with atrial fibrillation.

Inhibition of the renin-angiotensin axis can reduce the likelihood of atrial fibrillation (AF). However, the effects of angiotensin-converting-enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) on thrombogenicity in AF remain incompletely elucidated. Thisretrospective case-control study was conducted to evaluate whether the use of ACEI or ARB could reduce the incidence of left atrial appendage thrombus (LAAT) and spontaneous echocardiographic contrast (SEC) in patients with AF. A total of 199 AF patients who received both transesophageal echocardiogram (TEE) and transthoracic echocardiogram (TTE) successively on the same day from 2012 to 2016 were enrolled. Left atrial dimension, maximal left atrial volume (LAVmax), left ventricular end-diastolic dimension, left ventricular ejection fraction, and the ratio of the early transmitral flow velocity and the early mitral annular velocity (E/e') were determined. Longitudinal LA strain was evaluated using two-dimensional speckle tracking imaging at each LA segment. Peak systolic strain was calculated by averaging total segments. LAAT, LAA emptying flow velocity (LAAeV) and SEC were evaluated by TEE. Risk factors for LAAT and usage of ACEIs or ARBs were recorded. The incidence of LAAT was 27.6%. Among the patients with renin-angiotensin system (RAS) inhibitors, 20.5% were demonstrated to have LAAT, compared with 33.3% in the nonuser group (p = 0.044). LA peak systolic strain and LAAeV were significantly increased in patients with RAS inhibitors compared to the nonuser group (p = 0.002, p = 0.047, respectively). Patients with LAAT had higher CHA2DS2-VASc scores and evident SEC compared with those without LAAT (p = 0.000, p = 0.000, respectively). Usage of ACEIs/ARBs and antiplatelet drugs were frequent in patients with LAAT than in those without LAAT (p = 0.044, p = 0.000, respectively). Even after controlling for LAAT-related risk factors (age, body mass index, AF type, hypertension, diabetes mellitus, prior stroke or transient ischemic attack, drinking history and usage of antiplatelet drugs and LAVmax), use of RAS inhibitors remained significantly associated with a lower risk of LAAT (OR = 0.222; 95% CI 0.084-0.585, p = 0.002). This study shows that RAS inhibitors may be effective in reducing the risk of LAAT in patients with AF through atrial reverse remodeling.

Risk stratification of patients with left atrial appendage thrombus prior to catheter ablation of atrial fibrillation: An approach towards an individualized use of transesophageal echocardiography.

The need for transesophageal echocardiography (TEE) before catheter ablation of atrial fibrillation (CA-AF) is still being questioned. The aim of this study is to analyze patients' (patients) risk factors of left atrial appendage thrombus (LAAT) prior to CA-AF in daily clinical practice, according to oral anticoagulation (OAC) strategies recommended by current guidelines. All patients scheduled for CA-AF from 01/2015 to 12/2016 in our center were included and either treated with NOACs (novel-OAC; paused 24-hours preablation) or continuous vitamin K antagonists (INR 2.0-3.0). All patients received a preprocedural TEE at the day of ablation. Two groups were defined: (1) patients without LAAT, (2) patients with LAAT. The incidence of LAAT was 0.78% (13 of 1,658 patients). No LAAT was detected in patients with a CHA2 DS2 -VASc score of ≤1 (n = 640 patients) irrespective of the underlying AF type. Independent predictors for LAAT are: higher CHA2 DS2 -VASc scores (odds ratio [OR] 1.54, 95%-confidence interval [CI]: 1.07-2.23, P = 0.0019), a history of nonparoxysmal AF (OR 7.96, 95%-CI: 1.52-146.64, P = 0.049), hypertrophic cardiomyopathy (HCM; OR 9.63, 95% CI: 1.36-43.05, P = 0.007), and a left ventricular ejection fraction (LVEF) < 30% (OR 8.32, 95% CI: 1.18-36.29, P = 0.011). The type of OAC was not predictive (P = 0.70). The incidence of LAAT in patients scheduled for CA-AF is low. Therefore, periprocedural OAC strategies recommended by current guidelines seem feasible. Preprocedural TEE may be dispensed in patients with a CHA2 DS2 -VASc score ≤1. However, a CHA2 DS2 -VASc score ≥2, reduced LVEF, HCM, or history of nonparoxysmal AF are independently associated with an increased risk for LAAT.

Assessment of left atrial appendage filling pattern by using intravenous administration of microbubbles: Comparison between mitral stenosis and mitral regurgitation

Mitral stenosis (MS) and mitral regurgitation (MR) are the most frequent conditions that cause a dilation and dysfunction of the left atrial appendage (LAA). Despite similarly dilated LAA in patients with MS and MR, the incidence of LAA thrombi and the risk of thromboembolism is different between these patients. The purpose of this study was to characterize the filling pattern of LAA by using intravenous administration of perfluorocarbon-exposed dextrose albumin (PESDA) during transesophageal echocardiographic examination in patients with MS and MR. Twenty-four patients with moderate to severe MS, 12 patients with severe MR, and a control group including 30 patients with conditions other than mitral valve disease underwent transesophageal echocardiographic examination with an intravenous bolus injection of PESDA. LAA emptying and filling velocities and maximal and minimal areas of LAA and LAA ejection fraction were measured. Digital gray-scale intensity (GSI) of the left atrial (LA) and LAA cavity after PESDA injection was measured by off-line analysis. Compared with control patients, patients with MS or MR had larger maximal and minimal areas of LAA and reduced LAA ejection fraction. LAA peak emptying flow velocity was significantly lower in patients with MS compared with those of MR or control patients. LAA peak filling velocity was significantly lower in patients with MS compared with that of control patients. However, there was no significant difference of LAA peak filling velocity between the patients with MS and MR. There was no significant difference of GSI ratio of LAA and LA between patients with MR and control patients; however, GSI ratio of LAA and LA was significantly lower in patients with MS compared with that of MR. The incidence of LAA spontaneous echo contrast and LAA thrombi in patients with MS was significantly higher than that of the patients with MR and control subjects (P <.005). Despite similarly dilated LAA area and depressed contractile function of LAA in patients with MS and MR compared with control patients, profoundly impaired LAA filling with resultant flow stasis was demonstrated by contrast echocardiography in patients with MS. These findings may explain the higher incidence of LAA spontaneous echo contrast and thrombus in patients with MS.

Abstracts of literature

Abstracts of literature

Efficacy of anticoagulation in resolving left atrial and left atrial appendage thrombi: A transesophageal echocardiographic study

Transesophageal echocardiography (TEE) is the gold standard for evaluation of the left atrium and the left atrial appendage (LAA) for the presence of thrombi. Anticoagulation is conventionally used for patients with atrial fibrillation to prevent embolization of atrial thrombi. The mechanism of benefit and effectiveness of thrombi resolution with anticoagulation is not well defined. We used a TEE database of 9058 consecutive studies performed between January 1996 and November 1998 to identify all patients with thrombi reported in the left atrium and/or LAA. One hundred seventy-four patients with thrombi in the left atrial cavity (LAC) and LAA were identified (1.9% of transesophageal studies performed). The incidence of LAA thrombi was 6.6 times higher than LAC thrombi (151 vs 23, respectively). Almost all LAC thrombi were visualized on transthoracic echocardiography (90.5%). Mitral valve pathology was associated with LAC location of thrombi (P <.0001), whereas atrial fibrillation or flutter was present in most patients with LAA location of thrombi. Anticoagulation of 47 +/- 18 days was associated with thrombus resolution in 80.1% of the patients on follow-up TEE. Further anticoagulation resulted in limited additional benefit. LAC thrombi are rare and are usually associated with mitral valve pathology. Transthoracic echocardiography is effective in identifying these thrombi. LAA thrombi occur predominantly in patients with atrial fibrillation or flutter. Short-term anticoagulation achieves a high rate of resolution of LAA and LAC thrombi but does not obviate the need for follow-up TEE.