Determinants of left atrium thrombi in scheduled cardioversion: an ENSURE-AF study analysis

Artificial intelligence in detecting left atrial appendage thrombus by transthoracic echocardiography and clinical features: the Left Atrial Thrombus on Transoesophageal Echocardiography (LATTEE) registry

AIMS

Transoesophageal echocardiography (TOE) is often performed before catheter ablation or cardioversion to rule out the presence of left atrial appendage thrombus (LAT) in patients on chronic oral anticoagulation (OAC), despite associated discomfort. A machine learning model [LAT-artificial intelligence (AI)] was developed to predict the presence of LAT based on clinical and transthoracic echocardiography (TTE) features.

METHODS AND RESULTS

Data from a 13-site prospective registry of patients who underwent TOE before cardioversion or catheter ablation were used. LAT-AI was trained to predict LAT using data from 12 sites (n = 2827) and tested externally in patients on chronic OAC from two sites (n = 1284). Areas under the receiver operating characteristic curve (AUC) of LAT-AI were compared with that of left ventricular ejection fraction (LVEF) and CHA2DS2-VASc score. A decision threshold allowing for a 99% negative predictive value was defined in the development cohort. A protocol where TOE in patients on chronic OAC is performed depending on the LAT-AI score was validated in the external cohort. In the external testing cohort, LAT was found in 5.5% of patients. LAT-AI achieved an AUC of 0.85 [95% confidence interval (CI): 0.82-0.89], outperforming LVEF (0.81, 95% CI 0.76-0.86, P < .0001) and CHA2DS2-VASc score (0.69, 95% CI: 0.63-0.7, P < .0001) in the entire external cohort. Based on the proposed protocol, 40% of patients on chronic OAC from the external cohort would safely avoid TOE.

CONCLUSION

LAT-AI allows accurate prediction of LAT. A LAT-AI-based protocol could be used to guide the decision to perform TOE despite chronic OAC.

Treatment of Persistent Left Atrial Appendage Thrombus in Patients with Atrial Fibrillation on Adequate Oral Anticoagulation: Pathways of Care for All-comers and Heart Failure Patients

In patients with AF, the presence of left atrial/left atrial appendage (LA/LAA) thrombus is related to an increased risk of thromboembolic events. Anticoagulation therapy, either with vitamin K antagonists or novel oral anticoagulants (NOACs) is therefore mandatory in AF with LA/LAA thrombus in order to lower the risk of stroke or other systemic embolic events. Despite the efficacy of these treatments, some patients will have persistent LAA thrombus remaining or may have contraindications to oral anticoagulation. Currently, little is known about the occurrence, risk factors and resolution rate of LA/LAA thrombus in patients who are already under optimal chronic oral anticoagulation, including vitamin K antagonists or NOACs. The common action in clinical practice in this scenario is switching from one to another anticoagulant drug exhibiting a different mechanism of action. Repeated cardiac imaging is then advised within several weeks to visually verify thrombus dissolution. Finally, there is a substantial scarcity of data on the role and optimal use of NOACs after LAA occlusion. The aim of this review is to critically evaluate data and provide up-to-date information on the best antithrombotic strategies in this challenging clinical scenario.

Left Atrial Appendage Thrombosis and Oral Anticoagulants: A Meta-Analysis of Risk and Treatment Response

Left atrial appendage thrombus (LAAT) is the main cause of cardioembolism in patients with nonvalvular atrial fibrillation (AF). Emerging evidence indicates that direct oral anticoagulants (DOACs) may be a preferred, safer choice for patients with LAAT. However, current guidelines indicate vitamin K antagonist (VKA) as the preferred treatment for LAAT. We conducted a meta-analysis to compare the efficacy of VKA and DOAC for the treatment of LAAT. Methods: The search was conducted in the PubMed, Embase, Google Scholar, and Cochrane Library databases from inception to July 2022, with the language restricted to English. A first analysis was conducted to evaluate the risk of LAAT under VKA or DOAC treatment. A second analysis was conducted to compare the resolution of LAAT under VKA and DOAC treatment. Results: In 13 studies comparing LAAT incidence rates under VKA and DOAC treatment, significant superiority of DOAC was detected (pooled RR = 0.65, 95% CI = 0.47–0.90, p = 0.009) with moderate heterogeneity being identified in the pooled studies. In 13 studies comparing LAAT resolution under VKA and DOAC use, treatment with DOAC exhibited a significantly increased probability of LAAT resolution compared with VKA (pooled odds ratio = 1.52, 95% CI = 1.02–2.26, p = 0.040). Conclusions: This meta-analysis suggests a superiority of DOAC over VKA with respect to LAAT incidence in people with AF and the likelihood of LAAT resolution. Due to their established safety profile, DOAC is a preferable choice for anticoagulation, although further randomized controlled studies are warranted to provide further evidence of their suitability as a new recommended treatment.

Atrial cardiomyopathy: from cell to bedside

Atrial cardiomyopathy refers to structural and electrical remodelling of the atria, which can lead to impaired mechanical function. While historical studies have implicated atrial fibrillation as the leading cause of cardioembolic stroke, atrial cardiomyopathy may be an important, underestimated contributor. To date, the relationship between atrial cardiomyopathy, atrial fibrillation, and cardioembolic stroke remains obscure. This review summarizes the pathogenesis of atrial cardiomyopathy, with a special focus on neurohormonal and inflammatory mechanisms, as well as the role of adipose tissue, especially epicardial fat in atrial remodelling. It reviews the current evidence implicating atrial cardiomyopathy as a cause of embolic stroke, with atrial fibrillation as a lagging marker of an increased thrombogenic atrial substrate. Finally, it discusses the potential of antithrombotic therapy in embolic stroke with undetermined source and appraises the available diagnostic techniques for atrial cardiomyopathy, including imaging techniques such as echocardiography, computed tomography, and magnetic resonance imaging as well as electroanatomic mapping, electrocardiogram, biomarkers, and genetic testing. More prospective studies are needed to define the relationship between atrial cardiomyopathy, atrial fibrillation, and embolic stroke and to establish a prompt diagnosis and specific treatment strategies in these patients with atrial cardiomyopathy for the secondary and even primary prevention of embolic stroke.

Proposal for a clinical and an echocardiographic score for prediction of left atrial thrombosis in atrial fibrillation patients undergoing early electrical cardioversion

AIMS

Left atrial thrombosis (LAT) is usually detected by transesophageal echocardiography (TEE). The aim of the present study was to identify clinical and echocardiographic factors associated with left atrial thrombosis in atrial fibrillation (AF) patients undergoing early electrical cardioversion (ECV) in order to create scores that can predict LAT, in a non-invasive way.

METHODS

A consecutive cohort of patients with persistent AF scheduled for ECV was evaluated by transthoracic echocardiography and TEE. By a logistic regression model, variables significantly associated with LAT were assessed and introduced in predictive models to develop both a clinical and an echocardiographic prediction score for the presence of LAT.

RESULTS

In total, 125 patients [median 71 (range 49-88) years, 60.0% males] were enrolled. Transesophageal echocardiography showed LAT in 35 patients (28%). The clinical variables significantly associated with LAT were previous stroke (OR = 4.17), higher CHA₂ DS₂ -VASc score (OR = 1.93), lower estimated glomerular filtration rate (OR = 0.80), and higher brain natriuretic peptide levels (OR = 1.44). Among echocardiographic parameters, E/e' ratio was directly associated with LAT (OR = 2.25), while an inverse correlation was detected with left ventricular ejection fraction (OR = 0.43) and total global left atrial strain (OR = 0.59). Two prediction scores (clinical and echocardiographic) were developed. The positive predictive values of the clinical and the echocardiographic score were 80% and 100%, respectively, while the negative predictive values were 98% and 94%, respectively. Combined use of the scores reached a positive and negative predictive value of 100%.

CONCLUSIONS

When providing concordant information the two scores are able to correctly identify patients with or without LAT. An external validation is necessary to demonstrate their usefulness in the clinical practice.

Is transesophageal echocardiography necessary before electrical cardioversion in patients treated with non-vitamin K antagonist oral anticoagulants? Current evidence and practical approach

According to current guidelines, non-vitamin K antagonist oral anticoagulants (NOACs) should be used at least 3 weeks before planned electrical cardioversion. In accordance with international atrial fibrillation (AF) guidelines, transesophageal echocardiography (TEE) is a pre-procedural examination recommended as an alternative to adequate oral anticoagulation. The strategy related to qualifying patients treated with NOACs for pre-procedural TEE differs in individual centers. Therefore, it is necessary to create an algorithm that will standardize estimation of left atrial appendage thrombus (LAAT) prevalence risk and thereby qualify NOAC-treated patients to TEE in the most effective way. We assessed the available studies on LAAT predictors. Risk factors for LAAT formation are not necessarily the same as the risk factors for thromboembolic events in patients with AF. The main risk factor for LAAT are as follows: previous intracardiac thrombus, irregular use of NOAC, inappropriate dose reduction of NOAC, previous stroke, CHA2DS2-VASc score ≥ 3 points, glomerular filtration rate < 60 mL/min/1.73 m², reduced left ventricular ejection fraction, or left atrial enlargement. Based on available evidence, we proposed algorithm guarantees more systematic approach to performing TEE in patients undergoing electrical cardioversion.

Diagnosis and management of left atrial appendage thrombus in patients with atrial fibrillation undergoing cardioversion or percutaneous left atrial procedures: results of the European Heart Rhythm Association survey

Practices regarding indications and timing for transoesophageal echocardiography (TOE) before cardioversion (CV) of atrial fibrillation (AF) or left atrial (LA) interventional procedures, and preferred imaging techniques and pharmacotherapy, in cases of thrombus resistant to chronic oral anticoagulation (OAC) treatment, are largely unknown. The European Heart Rhythm Association (EHRA) conducted a survey to capture contemporary clinical practice in those areas of AF care. A 22-item online questionnaire was developed and distributed among the EHRA electrophysiology research network centres. The survey contained questions regarding indications, type and timing of imaging before CV or LA procedures and management of LA appendage (LAA) thrombus with special emphasis on thrombus resistant to OAC. Of 54 responding centres 63% were university hospitals. Most commonly, TOE would be performed in cases of inadequate or unclear pre-procedural anticoagulation, even in AF lasting <48 h (52% and 50%, respectively), and 15% of centres would perform TOE before AF ablation in all patients. If thrombus was diagnosed despite chronic OAC, the prevalent strategy was to change current OAC to another with different mechanism of action; 51% of centres would wait 3-4 weeks after changing the OAC before using another imaging test, and 60% of centres reported two attempts to dissolve the thrombus. Our survey showed a significant utilization of TOE before CV or AF ablation in European centres, extending beyond AF guidelines-suggested indications. When thrombus was diagnosed despite chronic pre-procedural OAC, most centres would use another anticoagulant drug with different mode of action.

Cardioversion of atrial fibrillation and atrial flutter revisited: current evidence and practical guidance for a common procedure

Cardioversion is widely used in patients with atrial fibrillation (AF) and atrial flutter when a rhythm control strategy is pursued. We sought to summarize the current evidence on this important area of clinical management of patients with AF including electrical and pharmacological cardioversion, peri-procedural anticoagulation and thromboembolic complications, success rate, and risk factors for recurrence to give practical guidance.

Vorhofflimmern und NOAK-Therapie: Benötigen wir eine transösophageale Echokardiografie vor Kardioversion?

Vorhofflimmern ist ein häufiger Grund für einen Schlaganfall. Insbesondere Patienten ohne adäquate Antikoagulation haben ein erhöhtes Risiko für thromboembolische Ereignisse (ca. 5–7%). Es liegt eine Assoziation zwischen Kardioversionen und embolischen Ereignissen vor. Durch eine orale Antikoagulation (OAK) mit Nicht-Vitamin-K-Antagonisten (NOAK) kann dieses Risiko auf unter 1% reduziert werden. Es gibt 2 unterschiedliche Kardioversionsstrategien. Zum einen kann eine Kardioversion nach 3-wöchiger effektiver Antikoagulation ohne weitere Bildgebung durchgeführt werden. Zum anderen kann nach Ausschluss einer intrakardialen Thrombenbildung durch eine TEE umgehend sicher kardiovertiert werden. Bei Vorhofflimmern sollte nach der Kardioversion eine effektive Antikoagulation für mindestens 4 Wochen erfolgen, unabhängig vom CHA2DS2-VASc-Score. Eine Bildgebung mittels TEE ist notwendig, wenn die Dauer einer effektiven Antikoagulation <3 Wochen ist, Unsicherheiten bezüglich der regelmäßigen und lückenlosen Medikamenteneinnahme bestehen oder ein hohes Risiko für linksatriale Thromben besteht.

Prevalence of left atrial thrombus by real time three-dimensional echocardiography in patients undergoing electrical cardioversion of atrial fibrillation: A contemporary cohort study

BACKGROUND

The prevalence of left atrial thrombi in patients scheduled for electrical cardioversion (ECV) of atrial fibrillation (AF) remains unknown in contemporary real-life practice.

METHODS AND RESULTS

Patients scheduled for ECV underwent transesophageal echocardiography (TEE) regardless of AF duration and type of anticoagulant. Of 277 consecutive patients (65% men, mean age 71 ± 10 years, CHA₂ DS₂ -VASc 3.1 ± 1.4), 92 were on direct oral anticoagulants (DOACs) and 99 on antivitamin K (AVK) oral agents for at least 3 weeks before and 4 after ECV. Eighty-five patients with paroxysmal AF on low-molecular-weight heparin were also considered. Real time three-dimensional TEE detected left atrial appendage (LAA) thrombus in 7% of patients, without significant difference among three groups (P = .334). Anticoagulation was ineffective in eight patients on AVK oral agents, two of them had thrombus. Eight patients assumed incorrectly DOACs, four of them had thrombus. Among the 175 patients on effective anticoagulation, five showed thrombus, three on AVK oral agents, and two on DOACs (P = .716). Effective anticoagulation was associated with reduced risk of thrombosis (OR: 0.16, 95%CI: 0.06-0.45, P = .001). In patients with correct anticoagulation, predictors of thrombus were CHA₂ DS₂ VASc (for each point of increment OR: 1.97, 95%CI: 1.08-3.61, P = .029), low left ventricular ejection fraction (OR: 0.92, 95%CI: 0.86-0.99, P = .026), and degree of spontaneous echo-contrast (for each point increase OR: 10, 95%CI: 2-39, P < .0001).

CONCLUSION

Patients with AF, on effective anticoagulation, had a prevalence of thrombus not negligible regardless of type of anticoagulant. TEE is prudent before ECV and mandatory if unsuccessful anticoagulation is proved or suspected.

Clinical risk predictors in atrial fibrillation patients following successful coronary stenting: ENTRUST-AF PCI sub-analysis

Aims

This subgroup analysis of the ENTRUST-AF PCI trial (ClinicalTrials.gov Identifier: NCT02866175; Date of registration: August 2016) evaluated type of AF, and CHA₂DS₂-VASc score parameters as predictors for clinical outcome.

Methods

Patients were randomly assigned after percutaneous coronary intervention (PCI) to either edoxaban (60 mg/30 mg once daily [OD]; n = 751) plus a P2Y₁₂ inhibitor for 12 months or a vitamin K antagonist [VKA] (n = 755) plus a P2Y₁₂ inhibitor and aspirin (100 mg OD, for 1–12 months). The primary outcome was a composite of major/clinically relevant non-major bleeding (CRNM) within 12 months. The composite efficacy endpoint consisted of cardiovascular death, stroke, systemic embolic events, myocardial infarction (MI), and definite stent thrombosis.

Results

Major/CRNM bleeding event rates were 20.7%/year and 25.6%/year with edoxaban and warfarin, respectively (HR [95% CI]: 0.83 [0.654–1.047]). The event rates of composite outcome were 7.26%/year and 6.86%/year, respectively (HR [95% CI]): 1.06 [0.711–1.587]), and of overall net clinical benefit were 12.48%/year and 12.80%/year, respectively (HR [(95% CI]: 0.99 [(0.730; 1.343]). Increasing CHA₂DS₂-VASc score was associated with increased rates of all outcomes. CHA₂DS₂-VASc score ≥ 5 was a marker for stent thrombosis. Paroxysmal AF was associated with a higher occurrence of MI (4.87% versus 2.01%, p = 0.0024).

Conclusion

After PCI in AF patients, increasing CHA₂DS₂-VASc score was associated with increased bleeding rates and CHA₂DS₂-VASc score (≥ 5) predicted the occurrence of stent thrombosis. Paroxysmal AF was associated with MI. These findings may have important clinical implications in AF patients.

Differences in Thromboembolic Complications Between Paroxysmal and Persistent Atrial Fibrillation Patients Following Electrical Cardioversion (From the ENSURE-AF Study)

It is unclear if patients with paroxysmal atrial fibrillation (AF) and persistent AF have different outcomes following electrical cardioversion (ECV). ENSURE-AF-a multicenter, prospective, randomized, open-label, blinded-endpoint evaluation trial-compared once-daily edoxaban 60 mg with enoxaparin-warfarin in 2,199 subjects undergoing ECV of nonvalvular AF (NCT02072434). Patients received ≥3 weeks of proper anticoagulation or transesophageal echocardiogram before ECV paroxysmal AF was defined as AF with spontaneous conversion of duration of <7 days; persistent AF was defined as AF lasting ≥7 days without spontaneous conversion. Clinical characteristics and outcomes were compared between subjects based on type of AF present at baseline. In total, 415 subjects had paroxysmal AF; 1,777 had persistent AF. Patients with paroxysmal AF were older (65.8 ± 10.3 vs 63.9 ± 10.5, p = 0.001) with more hypertension (82.7% vs 77.2%, p = 0.01) versus persistent AF patients. Congestive heart failure was more common in persistent AF (46.7%) versus paroxysmal AF (31.3%, p <0.0001). CHA₂DS₂-VASc (score >2: 52.0% vs 49.5%, p = 0.4375) and prior myocardial infarction (6.5% vs 6.8%, p = 0.91) did not significantly differ between groups. After ECV, primary endpoint events were numerically higher in paroxysmal AF versus persistent AF (1.5% vs 0.6%, p = 0.0571), approaching statistical significance. Of note, myocardial infarction was observed in paroxysmal AF (n = 4 vs 0), whereas persistent AF was accompanied by stroke (n = 0 vs 5; p <0.05). In conclusion, patients with paroxysmal AF had more frequent major cardiovascular events than patients with persistent AF. Composite event rates were driven mainly by myocardial infarction in patients with paroxysmal AF and by stroke in those with persistent AF. Overall, the absolute number of events was low after ECV under anticoagulation.

Atrial fibrillation patients undergoing percutaneous coronary intervention: dual or triple antithrombotic therapy with non-vitamin K antagonist oral anticoagulants

About 20% of all atrial fibrillation (AF) patients develop coronary artery disease, which requires coronary stenting [percutaneous coronary intervention (PCI)]. Thus, this subcohort of AF patients may require aggressive antithrombotic therapy encompassing vitamin K antagonist (VKA) or non-vitamin K antagonist oral anticoagulants (NOAC) plus aspirin and a P2Y12 inhibitor. At present, four clinical Phase IIIb trials using dabigatran, rivaroxaban, apixaban, or edoxaban, were published. These studies assessed the impact of NOACs as a part of DAT therapy vs. triple therapy. Compared with triple therapy, NOAC-based DAT has been shown to be associated with reduced major bleeding as well as intracranial haemorrhages. The benefit, however, is somewhat counterbalanced by a higher risk of stent-related ischaemia during the early phase of dual therapy. Thus, triple therapy after stenting is appropriate for at least 14 days with a maximum of 30 days. Thereafter, DAT including a NOAC is the therapy of choice in AF PCI patients to reduce the risk of bleeding during a 1 year of follow-up compared to VKA-based regimes. The present review summarizes the published study results and demonstrates differences in trial design and reported outcomes.