Diagnostic and therapeutic pathways for the malignant left atrial appendage: European Heart Rhythm Association physician survey

Comparative analysis of therapeutic strategies in atrial fibrillation patients with left atrial appendage thrombus despite optimal NOAC therapy

BACKGROUND AND AIMS

Left atrial appendage (LAA) thrombus is the primary cause of stroke and systemic embolism in atrial fibrillation (AF). Non-vitamin-K oral anticoagulants (NOACs) effectively reduce LAA thrombus prevalence and stroke risk. However, the optimal treatment of a NOAC-resistant thrombus remains unclear. We aimed to evaluate therapeutic strategies for resolving LAA thrombus in patients on optimal NOAC therapy.

METHODS

We retrospectively analyzed patients scheduled for cardioversion or catheter ablation of AF between 2014 and 2023 with LAA thrombus on transesophageal echocardiography (TEE) despite being on optimal NOAC therapy. We assessed how the applied management strategy affected thrombus resolution.

RESULTS

Among the analyzed 120 patients, a change to a different NOAC occurred in 41% of cases, a transition to a VKA in 30%, and the supplementation with antiplatelet therapy in 11%. In contrast, 18% of the patients received unchanged therapy. Follow-up imaging at 65 [44 - 95] days showed successful thrombus resolution in 92 (77%) of cases, predicted by a lower CHA2DS2-VASc score (p = 0.01). Any modification of antithrombotic therapy was an independent predictor of thrombus resolution (OR 5.28 [1.55-18], p = 0.01). Of the four strategies, there was a trend toward better thrombus resolution with switching to a VKA (OR 3.23 [1.03-10.1], p = 0.04).

CONCLUSION

Resolution of LAA thrombus in patients already on adequate NOAC treatment may require a revision of the anticoagulation strategy. In addition, transitioning from NOAC to VKA might be considered.

Left atrial appendage occlusion in atrial fibrillation: shaping the future of stroke prevention

Atrial fibrillation (AF) is the most common cardiac arrhythmia, significantly increasing the risk of thromboembolic events, particularly ischemic stroke. The left atrial appendage (LAA) is the predominant site of thrombus formation in patients with AF, making it a crucial target for stroke prevention strategies. Left atrial appendage occlusion (LAAO) has emerged as an important therapeutic alternative to oral anticoagulation, particularly in patients with contraindications to long-term anticoagulant therapy. This review examines the role of LAAO in AF management, discussing current indications, patient selection, procedural techniques, and clinical outcomes. We also explore the latest evidence from major clinical trials and real-world studies, highlighting the efficacy and safety of LAAO compared to standard anticoagulation. Additionally, we consider the unresolved questions and the potential future directions for this intervention, including emerging technologies and the integration of LAAO into broader AF management protocols. Our review underscores the growing importance of LAAO in reducing thromboembolic risk in AF patients, particularly those unable to tolerate traditional anticoagulation, and offers insights into the ongoing evolution of this treatment modality in clinical practice.

Antithrombotic therapy after left atrial appendage occlusion

INTRODUCTION

Left atrial appendage occlusion (LAAO) represents a strategy to minimize thromboembolic risk in atrial fibrillation (AF) patients. However, LAAO carries some risks of periprocedural bleeding, device embolization, peri-device leaks or device-related thrombosis; the latter is due to direct blood contact with the device, justifying and represents the rationale behind antithrombotic therapy following LAAO.

AREAS COVERED

A comprehensive literature search (PubMed, Web of Science, Cochrane) has been performed up to November 2024. Antithrombotic drugs after LAAO include vitamin K antagonists (VKA), direct oral anticoagulants (DOAC), antiplatelet drugs, and their combinations. Initially, high-intensity regimens were implemented, while current strategies prioritize simplified approaches to promote device healing without increasing the bleeding risk. The aims of our review were to define the rationale and implications for post-LAAO antithrombotic therapy and provide an overview of current evidence on various antithrombotic regimens.

EXPERT OPINION

The optimal post-LAAO antithrombotic regimen remains controversial, highlighting the need for randomized trials on this topic. Current data suggest that DOACs have the lowest probability of thromboembolic events and major bleeding, while DAPT may be preferred in patients who do not tolerate OAC; finally, single antiplatelet therapy or no antithrombotic therapy are alternative options for patients at high bleeding risk.

Management strategies to prevent stroke in patients with atrial fibrillation and malignant left atrial appendage

BACKGROUND

Patients with atrial fibrillation and malignant left atrial appendage (LAA) may benefit from LAA closure (LAAC); however, evidence is limited.

OBJECTIVE

The purpose of this study was to determine management strategies and clinical outcomes in patients with atrial fibrillation and malignant LAA.

METHODS

Malignant LAA was defined as a history of ischemic stroke and/or evidence of LAA thrombus despite continuous oral anticoagulation (OAC) therapy (continuous for ≥3 weeks). We studied 80 patients with malignant LAA treated with LAAC. We compared these patients first against 44 patients with malignant LAA treated with OAC alone and second against 114 patients without malignant LAA who were treated with LAAC for conventional indications.

RESULTS

Among patients with malignant LAA (first comparison), those treated with LAAC had a higher 1-year cumulative incidence rate of ischemic stroke than did patients treated with OAC alone (6.3% vs 5.3%; log-rank, P = .09) whereas the difference in stroke risk while receiving OAC was comparable (2.7% vs 5.3%; log-rank, P = .84). Furthermore, all disabling stroke events in patients with malignant LAA treated with LAAC occurred only while not receiving OAC. Among patients treated with LAAC (second comparison), those with malignant LAA had a higher 1-year cumulative incidence rate of ischemic stroke (and ischemic stroke due to device-related thrombosis) than did those without malignant LAA (6.3% vs 2.2%; log-rank, P = .009 and 2.2% vs 0%; log-rank, P = .04, respectively). However, these differences in stroke risk were no longer significant while receiving OAC (2.7% vs 1.0%; log-rank, P = .11).

CONCLUSION

Combination performing LAAC and continuation of OAC may be options to prevent ischemic stroke in patients with high thromboembolic risk and malignant LAA.

Heart Failure and the Non-Resolution of Atrial Thrombus Detected in Anticoagulated Patients with Non-Valvular Atrial Fibrillation

BackgroundTo investigate the relationship between heart failure (HF) and the non-resolution of atrial thrombus detected in anticoagulated patients with non-valvular atrial fibrillation (NVAF).MethodsThis was a single-center, observational, retrospective, and prospective study. Anticoagulated patients with NVAF and atrial thrombus identified by transesophageal echocardiography or cardiac computed tomography angiography were consecutively enrolled. All patients received follow-up imaging within 6 months to assess the resolution of atrial thrombus. The primary endpoint was the resolution of atrial thrombus and the secondary endpoint was the occurrence of ischemic stroke, major bleeding, and all-cause death during the follow-up period.ResultsAmong 8987 patients with NVAF scheduled for catheter ablation or cardioversion, 70 anticoagulated patients with atrial thrombus were final analyzed. The average age was 61.8±10.6 years, 62.9% of them were men, and 32 (45.7%) patients presented with HF. Within the 6-month follow-up period, atrial thrombus resolution was observed in 47 (67.1%) patients. The rate of atrial thrombus resolution was lower in patients with baseline HF (50.0% vs 81.6%). In the adjusted logistic regression analysis model, HF was independently associated with the non-resolution of atrial thrombus (adjusted OR: 5.38, 95% CI: 1.19-24.27). During the median follow-up period of 4.5 years, four ischemic stroke events occurred in four patients. None of the patients in this study experienced major bleeding events or death during follow-up.ConclusionsHF was associated with the non-resolution of atrial thrombus detected in anticoagulated patients with NVAF. Further research is needed to identify optimal therapeutic approaches for this high-risk population.

An International Consensus Practical Guide on Left Atrial Appendage Closure for the Non-implanting Physician: Executive Summary

Many patients with atrial fibrillation (AF) who are in need of stroke prevention are not treated with oral anticoagulation or discontinue treatment shortly after its initiation. Despite the availability of direct oral anticoagulants (DOACs), such undertreatment has improved somewhat but is still evident. This is due to continued risks of bleeding events or ischemic strokes while on DOAC, poor treatment compliance, or aversion to anticoagulant therapy. Because of significant improvements in procedural safety over the years left atrial appendage closure (LAAC), using a catheter-based, device implantation approach, is increasingly favored for the prevention of thromboembolic events in AF patients who cannot have long-term oral anticoagulation. This article is an executive summary of a practical guide recently published by an international expert consensus group, which introduces the LAAC devices and briefly explains the implantation technique. The indications and device follow-up are more comprehensively described. This practical guide, aligned with published guideline/guidance, is aimed at those non-implanting physicians who may need to refer patients for consideration of LAAC.

Morphological and functional assessment of the left atrial appendage in daily practice: a comprehensive approach using basic and advanced echocardiography with practical tips

Cardioembolic stroke is the most serious and life-threatening complication of atrial fibrillation (AF), with an associated mortality up to 30% at 12 months. Approximately 47% of thrombi in valvular AF and 91% of thrombi in nonvalvular AF are localized in the left atrial appendage (LAA). Therefore, identification or exclusion of LAA thrombi is critical in many clinical situations. It is essential to assess LAA morphology and function using imaging modalities (particularly echocardiography) before, during, and after interventional procedures such as AF ablation and LAA occlusion. This review article describes the anatomical, physiological, and pathological background of the LAA, followed by an assessment of different echocardiographic modalities. Many practical points are included to improve the diagnostic accuracy and to minimize errors during image acquisition and interpretation. In each clinical scenario where LAA is the crucial target, specific and essential information and parameters are collected.

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 multicentre observational study investigating patients with atrial fibrillation (AF) and silent LA thrombi detected by transoesophageal 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 cut-off) 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 ischaemic 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).

CONCLUSION

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.

Practical guide on left atrial appendage closure for the non-implanting physician: an international consensus paper

A significant proportion of patients who suffer from atrial fibrillation (AF) and are in need of thromboembolic protection are not treated with oral anticoagulation or discontinue this treatment shortly after its initiation. This undertreatment has not improved sufficiently despite the availability of direct oral anticoagulants which are associated with less major bleeding than vitamin K antagonists. Multiple reasons account for this, including bleeding events or ischaemic strokes whilst on anticoagulation, a serious risk of bleeding events, poor treatment compliance despite best educational attempts, or aversion to drug therapy. An alternative interventional therapy, which is not associated with long-term bleeding and is as effective as vitamin K anticoagulation, was introduced over 20 years ago. Because of significant improvements in procedural safety over the years, left atrial appendage closure, predominantly achieved using a catheter-based, device implantation approach, is increasingly favoured for the prevention of thromboembolic events in patients who cannot achieve effective anticoagulation. This management strategy is well known to the interventional cardiologist/electrophysiologist but is not more widely appreciated within cardiology or internal medicine. This article introduces the devices and briefly explains the implantation technique. The indications and device follow-up are more comprehensively described. Almost all physicians who care for adult patients will have many with AF. This practical guide, written within guideline/guidance boundaries, is aimed at those non-implanting physicians who may need to refer patients for consideration of this new therapy, which is becoming increasingly popular.

Implementation and first outcomes of a novel standard operating procedure for preprocedural transoesophageal echocardiography screening in course of atrial arrhythmia ablation

AIMS

Preprocedural transoesophageal echocardiography (TEE) screening for left atrial (LA) thrombi is the standard of care in many centres performing atrial fibrillation (AF) ablation. However, TEE imposes procedural risks for patients and is often challenging to implement in daily practice, besides causing patient discomfort. At our centre, a novel standard operating procedure (SOP) was implemented, aiming to identify patients that can be exempt from TEE screening. We aimed to assess whether this screening approach may reduce preprocedural TEEs without imposing patients of higher risks for cerebrovascular events (CVEs).

METHODS AND RESULTS

Data of 1874 consecutive patients treated by catheter ablation of LA arrhythmias between 2018 and 2022 were retrospectively analysed. A cohort of 937 patients, where decision to perform TEE screening was based on a new SOP (considering rhythm at admission, CHA2DS2-VASc score, and sufficient anticoagulation), was compared to a matched cohort receiving TEE before every procedure. Number of performed TEEs and incidences of CVEs were compared. Implementation of the new SOP led to a 67% reduction in TEEs performed (old SOP: 933 vs. new SOP: 305). No significant differences between the groups were detected regarding transitory ischaemic attack (old SOP: 5 vs. new SOP: 3; P = 0.48) and stroke (no events). No solid thrombi were detected during TEE screening.

CONCLUSION

The number of preprocedural screening TEEs before AF ablation procedures can be safely reduced by applying risk stratification based on rhythm at admission and CHA2DS2-VASc score, if anticoagulation was performed properly.