Usefulness of brain natriuretic peptide for predicting left atrial appendage thrombus in patients with unanticoagulated nonvalvular persistent atrial fibrillation

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

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

Predictors of thrombosis of left atrium and its appendage before catheter ablation or cardioversion in patients with non-valvular atrial fibrillation or atrial flutter

Aim. To determine the incidence of left atrial (LA) and/or LA appendage (LAA) thrombosis in patients with non-valvular atrial fibrillation (AF) (NAF) or atrial flutter (AFL) on transesophageal echocardiography (TEE) before elective catheter ablation (CA) or cardioversion (CV) and characterize the predictors of LA/LAA thrombosis among the indicators available in the routine practice of cardiologists and general practitioners.

Material and methods. In this retrospective, single-center, casecontrol study, the medical records of 1994 patients with NAF or AFL for the period 2014-2019, who underwent TEE before CA or elective CV, were analyzed. A thrombus in the LA/LAA was detected in 33 (1,6%) of them. For the comparison group, 167 patients were randomly selected without LA/LAA thrombosis. Demographic, anamnestic and clinical parameters, transthoracic echocardiography data, and laboratory results were analyzed as potential predictors of LA/LAA thrombosis.

Results. Patients with LA/LAA thrombosis were older (mean age, 64,8±1,6 vs 59,4±10,8 (p=0,01), more often had persistent or longstanding persistent AF, hypertension, heart failure, enlarged LA, lower left ventricular ejection fraction (LVEF) and estimated glomerular filtration rate, as well as more severe symptoms according to the modified European Heart Rhythm Association (EHRA) score and a higher CHA2DS2-VASc score (median, 4,0 vs 2,0; p=0,0001). Oral anticoagulants were taken by 88% of patients; there were no significant differences in the presence and composition of anticoagulant therapy between the groups. Functional class (FC) according to the modified EHRA score (odds ratio (OR), 5,4; 95% confidence interval (CI): 1,9814,96; p=0,001) and LVEF were independent predictors of LA/LAA thrombosis (OR, 0,87; 95% CI: 0,80-0,95; p=0,002). For EHRA class 3-4, the OR was 5,1; 95% CI: 2,3-11,4 (p<0,0001), for LVEF <48% — 7,4; 95% CI: 1,2-46,7 (p=0,03). For EHRA class 3-4, the sensitivity for LA/LAA thrombosis was 93,7%, specificity — 71,9%, positive predictive value — 50,0%, negative predictive value — 87,6%; for LVEF <48% — 66,7, 32,3, 31,9 and 91,6%, respectively.

Conclusion. In the studied group of patients with NAF or AFL, without severe structural heart disease and severe concomitant diseases, most of whom received oral anticoagulants, LA/LAA thrombosis at TEE before elective CA or CV was detected in 1,6% of cases. Among the indicators available in routine medical practice, the severity of arrhythmia symptoms, assessed by the modified EHRA score, and lower LVEF were independent predictors of LA/LAA thrombosis.

Atrial Fibrillation, thromboembolic risk, and the potential role of the natriuretic peptides, a focus on BNP and NT-proBNP - A narrative review

Atrial fibrillation (AF) is one of the most commonly encountered arrythmia in clinical practice. AF itself can be driven by genetic predisposition, ectopic electrical activity, and abnormal atrial tissue substrates. Often there is no single etiological mechanism, but rather a combination of factors that feed back to remodel and worsen tissue substrate, "AF begets AF". The clinical consequences of AF can often include emboli, heart failure, and early mortality. The classical AF cardioembolic (CE) concept requires thrombus formation in the left atrial appendage, with subsequent embolization. The temporal dissociation between AF occurrence and CE events has thrown doubt on AF as the driver of this mechanism. Instead, there has been a resurgence of the "atrial cardiomyopathy" (ACM) concept. An ACM is proposed as a potential mechanism of embolic disease through promotion of prothrombotic mechanisms, with AF instead reflecting atrial disease severity. Regardless, AF has been implicated in 25% to 30% of cryptogenic strokes. Natriuretic peptide(NP)s have been shown to be elevated in AF, with higher levels of both NT-proBNP and BNP being predictive of incidental AF. NPs potentially reflect the atrial environment and could be used to identify an underlying ACM. Therefore, this narrative review examines this evidence and mechanisms that may underpin the role of NPs in identifying atrial dysfunction, with focus on both, BNP and NTproBNP. We explore their potential role in the prediction and screening for both, ACM and AF. Moreover, we compare both NPs directly to ascertain a superior biomarker.

Diagnosis and Management of Left Atrium Appendage Thrombosis in Atrial Fibrillation Patients Undergoing Cardioversion

Atrial fibrillation is the most common cardiac arrhythmia and is associated with an increased risk of stroke and thromboembolic complications. A rhythm control strategy with both electrical and pharmacological cardioversion is recommended for patients with symptomatic atrial fibrillation. Anticoagulant therapy for 3–4 weeks prior to cardioversion is recommended in order to avoid thromboembolic events deriving from restoring sinus rhythm. Transesophageal echocardiography has a pivotal role in this setting, excluding the presence of left atrial appendage thrombus before cardioversion. The aim of this review is to discuss the epidemiology and risk factors for left atrial appendage thrombosis, the role of echocardiography in the decision making before cardioversion, and the efficacy of different anticoagulant regimens on the detection and treatment of left atrial appendage thrombosis.

Impact of low-voltage zones on the left atrial anterior wall on the reduction in the left atrial appendage flow velocity in persistent atrial fibrillation patients

BACKGROUND

The reduction in the left atrial appendage (LAA) flow velocity is related to the presence of emboli in atrial fibrillation (AF) patients. The LAA is located on the left superior side of the left atrial (LA) anterior wall, and we investigated the relationship between the reduction in the LAA flow velocity (LAAFV) and low voltage zones (LVZs < 0.5 mV) on the LA anterior wall.

METHODS

In 146 persistent AF patients, LAAFV measurements, by transesophageal echocardiography, and catheter ablation were performed. LA mapping was performed before ablation during sinus rhythm, and the locations of any anterior-LVZs were documented.

RESULTS

Eighty-one patients had a documented LVZ on the LA anterior wall, and those with an LVZ had a significantly lower LAAFV compared to those without (anterior-LVZ(+) vs. anterior-LVZ(-) = 26 ± 11 vs. 34 ± 10 cm/s, p < 0.001), while no significant difference was observed when compared to the other LVZ regions. A low-LAAFV (≦ 20 cm/s) was observed in 36 patients, and the CHADS₂-vasc score and existence of an anterior-LVZ were associated with a low-LAAFV. In patients with anterior-LVZs, the distance between the anterior-LVZ and LAA orifice correlated with a low LAAFV (r = 0.534, p < 0.001) as compared to the surface area of the anterior-LVZ (r = - 0.288, p = 0.009).

CONCLUSIONS

In persistent AF patients, an LVZ on the LA anterior wall was associated with a low LAAFV. In addition, an anterior-LVZ located near the LAA orifice was further related to a reduction in the LAAFV.

Impact of B-type natriuretic peptide level on the risk of left atrial appendage thrombus in patients with nonvalvular atrial fibrillation: a prospective study

Background

The impact of B-type natriuretic peptide (BNP) level on the risk of left atrial appendage (LAA) thrombus in patients with nonvalvular atrial fibrillation (NVAF) has not been prospectively studied.

Methods

In two academic medical centers, we obtained BNP levels immediately prior to transesophageal echocardiogram performed to exclude LAA thrombus in patients with NVAF.

Results

Among 261 subjects (mean age 65 ± 12 years; 30 % women) with NVAF, 17 (6.5 %) had LAA thrombus and 85 (32.6 %) had at least mild spontaneous echo contrast (SEC). Mean BNP level was significantly higher in patients with LAA thrombus [775 ± 678 vs. 384 ± 537, P = 0.001]. Receiver operator characteristics analysis demonstrated that BNP has a good discriminatory capacity for LAA thrombus (area under the curve, 0.74; 95 % confidence interval [CI], 0.63–0.85; P = 0.001); BNP ≥ 67 pg/mL was 100 % sensitive and 20 % specific for LAA thrombus. Multivariate logistic regression analysis demonstrated that BNP was not independently associated with LAA thrombus (odds-ratio, 1.05 per 100 pg/mL increment; CI, 0.99–1.12; P = 0.127) after adjusting for CHA₂DS₂-VASc score; while the latter was independently associated with LAA thrombus after adjusting for BNP level (odds-ratio, 1.46 per CHA₂DS₂-VASc point; CI, 1.09–1.96; P = 0.011). Nonetheless, BNP was associated with SEC in univariate and multivariate analysis, after adjusting for the CHA₂DS₂-VASc score, (odds-ratio, 1.08; CI, 1.02–1.14; P = 0.005).

Conclusions

BNP is predictive of SEC. However, it does not provide significant incremental value in the prediction of LAA thrombus.