Should left atrial appendage closure be considered in resistant left atrial appendage thrombus cases? 'Former Foe, New Ally'.

BACKGROUND: The study explores left atrial appendage closure (LAAC) as a safe and effective alternative to anticoagulation for atrial fibrillation (AF) patients at high bleeding risk. Complications, such as cardioembolic events due to left atrial appendage thrombus (LAAT), highlight the need for alternative stroke prevention strategies. AIMS: This research assesses LAAC's safety and efficacy in patients with LAAT, aiming to offer valuable insights into its potential as a viable option for stroke prevention in such cases. METHODS: The study included 205 patients who underwent LAAC using specific devices between September 2015 and February 2023. Among them, 32 patients had persistent LAAT. Baseline characteristics, antithrombotic medications, risk scores, and LAAC indications were documented. Patients were followed to monitor significant clinical events like stroke, cardiovascular mortality, and all-cause mortality. RESULTS: The mean age was 71.9 and mostly female. Indications for LAAC were ischemic cerebrovascular events (CVE) despite anticoagulation (25%), bleeding complications (major/minor, 37.5% each), or both. Successful LAA closure was achieved in all cases, with minimal pericardial effusion in one. One-month follow-up showed no major events or device-related issues. Median follow-up of 16.5 months saw 21.9% non-cardiac deaths. The study underscores LAAC's efficacy for stroke prevention in patients with persistent LAAT. CONCLUSIONS: The LAAC in cases of LAAT, whether pursued initially or as a deferred approach, demonstrates feasibility and safety, exhibiting notable procedural success and minimal incidence of periprocedural complications.

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.

Resolution of left atrial appendage thrombi: No difference between phenprocoumon and non-vitamin K-dependent oral antagonists.

BACKGROUND: Atrial fibrillation is the most important risk factor for left atrial appendage (LAA) thrombi, a potentially life-threatening condition. Thrombus resolution may prevent embolic events and allow rhythm-control strategies, which have been shown to reduce cardiovascular complications. HYPOTHESIS: There is no significant difference between phenprocoumon and non-Vitamin K-dependent oral anticoagulants (NOACs) in the resolution of LAA-thrombi in a real-world setting. METHODS: Consecutive patients with LAA-thrombi from June 2013 to June 2017 were included in an observational single-center analysis. The primary endpoint was defined as the resolution of the thrombus. The observational period was 1 year. Resolutions rates in patients on phenprocoumon or NOACs were compared and the time to resolution was analyzed. RESULTS: We identified 114 patients with LAA-thrombi. There was no significant difference in the efficacy of resolution between phenprocoumon and NOACs (p = .499) at the time of first control which took place after a mean of 58 ± 42.2 (median 48) days. At first control most thrombi were dissolved (74.6%). The analysis after set-time intervals revealed a resolution rate of 2/3 of LAA-thrombi after 8-10 weeks in the phenprocoumon and NOAC groups. After 12 weeks a higher number of thrombi had resolved in the presence of NOAC (89.3%) whereas in the presence of phenprocoumon 68.3% had resolved (p = .046). CONCLUSION: In this large observational study NOACs were found to be potent drugs for the resolution of LAA-thrombi. In addition, the resolution of LAA-thrombi was found to be faster in the presence of NOAC as compared to phenprocoumon.

Assessment of LAA Strain and Thrombus Mobility and Its Impact on Thrombus Resolution-Added-Value of a Novel Echocardiographic Thrombus Tracking Method.

PURPOSE: The mobility of left atrial appendage (LAA) thrombi and changes hereof under anticoagulation may serve as a marker of both risk of embolism and efficacy of treatment. In this study, we sought to evaluate thrombus mobility and hypothesized that LAA dynamics and thrombus mobility could serve as a baseline marker of thrombus dissolvability. METHODS: Patients with two-dimensional transesophageal echocardiographic images of the LAA, and with evidence of LAA thrombus were included in this study. Using a speckle tracking algorithm, functional information from the LAA and thrombi of different patients was computed. While the LAA motion was quantified through the longitudinal strain, thrombus mobility was evaluated using a novel method by directly tracking the thrombus, isolated from the global cardiac motion. Baseline characteristics and echocardiographic parameters were compared between responders (thrombus resolution) and non-responders (thrombus persistence) to anticoagulation. RESULTS: We included 35 patients with atrial fibrillation with evidence of LAA thrombi. Patients had a mean age of 72.9 ± 14.1 years, exhibited a high risk for thromboembolism (CHA2DS2-VASc-Score 4.1 ± 1.5) and had moderately reduced LVEF (41.7 ± 14.4%) and signs of diastolic dysfunction (E/E' = 19.7 ± 8.5). While anticoagulation was initiated in all patients, resolution was achieved in 51.4% of patients. Significantly higher LAA peak strain (- 3.0 ± 1.3 vs. - 1.6 ± 1.5%, p < 0.01) and thrombus mobility (0.33 ± 0.13 mm vs. 0.18 ± 0.08 mm, p < 0.01) were observed in patients in whom thrombi resolved (i.e. responders against non-responders). Receiver operating characteristic (ROC) analysis revealed a high discriminatory ability for thrombus mobility with regards to thrombus resolution (AUC 0.89). CONCLUSION: Isolated tracking of thrombus mobility from echocardiographic images is feasible. In patients with LAA thrombus, higher thrombus mobility appeared to be associated with thrombus resolution. Future studies should be conducted to evaluate the role of the described technique to predict LAA thrombus resolution or persistence.

Left Atrial Appendage Occlusion in Patients With Thrombus in Left Atrial Appendage.

BACKGROUND: Atrial appendage (LAA) occlusion is a therapeutic option for thromboembolic prevention in atrial fibrillation (AF) patients who have contraindications to oral anticoagulation (OAC) or high risk of bleeding. Traditionally, thrombus in the LAA has been considered a contraindication for LAA occlusion. Recently, resistant thrombus formation in patients using OACs was suggested as an indication for LAA occlusion. METHODS AND RESULTS: In this single-center study, we evaluated the safety and efficacy of LAA occlusion in patients with a thrombus in the LAA. Twelve non-valvular AF patients who had a thrombus in the LAA were enrolled. The mean age was 71.8 years (range, 62-83 years). Permanent AF was present in all patients. Mean CHA2DS2-VASc score was 4.9 (range, 2-8) and mean HAS-BLED score was 4.8 (range, 3-6). Thrombi in the LAA were classified as type 1 (proximal to mid) and type 2 (distal) in 3 and 9 patients, respectively. Median follow-up duration was 12 months (interquartile range, 6-24 months). LAA occlusion was performed successfully with Amplatzer Amulet device without any significant periprocedural adverse events in all 12 patients. Transesophageal echocardiography (TEE) was performed at 1 and 6 months post procedure. Cardiovascular and all-cause mortality, significant ischemic cerebrovascular events, worsening heart failure, and major bleeding events did not occur during follow-up. Device-related thrombus was not observed with TEE in any patient. CONCLUSION: Our study showed that percutaneous LAA closure could be a therapeutic option for patients with resistant LAA thrombus.

Left atrial appendage thrombi relate to easily accessible clinical parameters in patients undergoing atrial fibrillation transcatheter ablation: A multicenter study.

BACKGROUND: Transesophageal echocardiography (TEE) is routinely performed before atrial fibrillation (AF) transcatheter ablation to exclude the presence of left atrial (LA) or LA appendage (LAA) thrombi. The aim of the study is to evaluate if easily accessible clinical parameters may relate to the presence of LA or LAA thrombi to identify patients who could potentially avoid TEE. METHODS AND RESULTS: Between January 2012 and September 2014, data from 1539 consecutive patients undergoing TEE, as a work-up before AF transcatheter ablation, in six large volume centers were collected. Baseline clinical features, CHA2DS2-VASc score, transthoracic echocardiography and presence of thrombi at TEE were recorded. Exclusion criteria were valvular, hypertrophic or dilated cardiomyopathy, previous heart surgery or an ejection fraction ≤35%. Mean age was 59.6±10.4years, 1215 (78.9%) were males; 951 (62.9%) presented in sinus rhythm (SR) on admission, 324 (21.1%) had undergone at least one previous ablation and 900 (58.5%) had CHA2DS2-VASc score 0-1. Thrombi were encountered in 12 patients (0.8%). SR at TEE independently related to the absence of thrombi (OR 5.15, 95% CI 1.38-19.02, p=0.015); in addition to this, no patient with a CHA2DS2-VASc score 0-1 and SR on admission presented thrombi at TEE (specificity 100%, p=0.011). CONCLUSION: In a selected population of patients referred for AF ablation, LA/LAA thrombi prevalence is low. No patients in SR with CHA2DS2-VASc score 0-1 presented LAA thrombi at TEE, identifying a significant subset of patients who could potentially safely be spared from pre-procedural TEE.

A low-dose, dual-phase cardiovascular CT protocol to assess left atrial appendage anatomy and exclude thrombus prior to left atrial intervention.

Assessment of the left atrial appendage (LAA) for thrombus and anatomy is important prior to atrial fibrillation (AF) ablation and LAA exclusion. The use of cardiovascular CT (CCT) to detect LAA thrombus has been limited by the high incidence of pseudothrombus on single-pass studies. We evaluated the diagnostic accuracy of a two-phase protocol incorporating a limited low-dose delayed contrast-enhanced examination of the LAA, compared with a single-pass study for LAA morphological assessment, and transesophageal echocardiography (TEE) for the exclusion of thrombus. Consecutive patients (n = 122) undergoing left atrial interventions for AF were assessed. All had a two-phase CCT protocol (first-past scan plus a limited, 60-s delayed scan of the LAA) and TEE. Sensitivity, specificity, diagnostic accuracy, positive (PPV) and negative predictive values (NPV) were calculated for the detection of true thrombus on first-pass and delayed scans, using TEE as the gold standard. Overall, 20/122 (16.4 %) patients had filling defects on the first-pass study. All affected the full delineation of the LAA morphology; 17/20 (85 %) were confirmed as pseudo-filling defects. Three (15 %) were seen on late-pass and confirmed as true thrombi on TEE; a significant improvement in diagnostic performance relative to a single-pass scan (McNemar Chi-square 17, p < 0.001). The sensitivity, specificity, diagnostic accuracy, PPV and NPV was 100, 85.7, 86.1, 15.0 and 100 % respectively for first-pass scans, and 100 % for all parameters for the delayed scans. The median (range) additional radiation dose for the delayed scan was 0.4 (0.2-0.6) mSv. A low-dose delayed scan significantly improves the identification of true LAA anatomy and thrombus in patients undergoing LA intervention.

Embryology and Anatomy of the Left Atrial Appendage: Why Does Thrombus Form?

The left atrial appendage (LAA) is a long tubular structure that opens into the left atrium. In patients with atrial fibrillation, the LAA develops mechanical dysfunction and fibroelastotic changes on the endocardial surface. The complex anatomy of the LAA makes it a good site for relative blood stasis. In addition, systemic factors exacerbate the hypercoagulable state, eventually resulting in endothelial dysfunction, release of tissue factor, and production of inflammatory cytokines and oxidative free radicals, and eventually initiating the coagulation cascade. Thus, the LAA is susceptible to thrombus formation and is the most common source of systemic thromboembolism.