Device-Related Thrombus After Left Atrial Appendage Occlusion: Clinical Impact, Predictors, Classification, and Management

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.

Percutaneous Left Atrial Appendage Closure: Supporting Evidence, Limitations and Future Directions

Percutaneous Left Atrial Appendage Occlusion (LAAO) has emerged as a promising intervention for stroke prevention in patients with atrial fibrillation who are contraindicated for long-term anticoagulation therapy. Despite its growing adoption, a comprehensive review of the LAAO procedure is essential to consolidate the supporting evidence, identify limitations, and outline future directions. This review aims to evaluate the efficacy and safety of LAAO, drawing on clinical trials and real-world studies to provide a balanced perspective. Additionally, we address the limitations of current research, including variability in patient selection, procedural techniques, and follow-up protocols. By highlighting gaps in the knowledge and areas for improvement, this review aims to guide future research efforts to optimize and expand the therapeutic potential of LAAO.

5-Year Results From the AMPLATZER Amulet Left Atrial Appendage Occluder Randomized Controlled Trial

BACKGROUND

The Amulet IDE trial (AMPLATZER Amulet Left Atrial Appendage Occluder [LAAO] Investigational Device Exemption [IDE] Trial) evaluated the safety and effectiveness of the Amulet occluder (Abbott) in patients with nonvalvular atrial fibrillation. The Amulet IDE trial is the largest randomized LAAO trial, comparing the Amulet occluder with the Watchman 2.5 device (Boston Scientific).

OBJECTIVES

This analysis presents the 5-year results from the trial comparing the 2 devices head to head.

METHODS

Patients enrolled in the Amulet IDE trial were at a high risk of stroke or systemic embolism defined as a CHADS2 score ≥2 or CHA2DS2-VASc score ≥3. Oral anticoagulation (OAC) use and key clinical outcomes are presented through 5 years.

RESULTS

A total of 1,878 patients were randomized, with 1,833 undergoing a device implantation attempt (n = 917, Amulet occluder; and n = 916, Watchman device). A significantly higher percentage of patients were free of OAC in the Amulet occluder group at each follow-up visit, with 94.0% and 90.9% free of OAC at the last 5-year follow-up visit in the Amulet and Watchman device groups, respectively (P = 0.009). The 5-year clinical outcomes were similar between the Amulet and Watchman devices, including the composite of ischemic stroke or systemic embolism (7.4% vs 7.1%; P = 0.851), the composite of stroke, systemic embolism, or cardiovascular death (20.3% vs 20.7%; P = 0.666), major bleeding (20.1% vs 20.0%; P = 0.882), cardiovascular (CV) death (14.3% vs 15.4%; P = 0.429), and all-cause death (28.7% vs 31.1%; P = 0.217). Annualized ischemic stroke rates at 5 years were low and the same for Amulet (1.6%/y) and Watchman (1.6%/y) devices. Strokes in patients with the Amulet occluder were less severe (n = 38, nondisabling; n = 11, disabling; n = 11, fatal; n = 12, unknown) than strokes in patients with the Watchman device (n = 19, nondisabling; n = 22, disabling; n = 17, fatal; n = 10, unknown). Moreover, device factors (device-related thrombus or peridevice leak ≥3 mm) preceded stroke events and CV deaths more frequently in patients with the Watchman device (n = 63) compared with patients with the Amulet occluder (n = 31).

CONCLUSIONS

The 5-year outcomes from the largest randomized LAAO clinical trial demonstrated the long-term safety and effectiveness of the Amulet occluder and Watchman 2.5 devices. The dual-seal Amulet occluder reduces atrial fibrillation-related thromboembolic events while eliminating the need for long-term OAC. (AMPLATZER Amulet Left Atrial Appendage Occluder [LAAO] Investigational Device Exemption [IDE] Trial [Amulet IDE trial]; NCT02879448).

Characterization and Clinical Outcomes of High-Risk Device-Related Thrombus in the Amulet IDE Trial

BACKGROUND

Characteristics of device-related thrombus (DRT) may differ between types of left atrial appendage occlusion devices, and the association of different DRT characteristics to clinical outcomes is largely unknown.

OBJECTIVES

The incidence, characteristics, and clinical outcomes through 5 years of high- and low-risk DRTs were assessed in the Amulet IDE trial (AMPLATZER Amulet Left Atrial Appendage Occluder [LAAO] Investigational Device Exemption [IDE] Trial).

METHODS

An independent core laboratory analyzed all available images at the required 45-day and 12-month visits, and clinical events were reported through 5 years' post-left atrial appendage occlusion.

RESULTS

Of the 1,788 patients with a successful device implant, DRT was observed in 3.3% (30 of 903) and 4.5% (40 of 885) of Amulet and Watchman 2.5 device patients throughout 12 months, respectively (P = 0.192). DRTs were successfully classified as high risk if pedunculated, mobile, >3 mm in thickness, or without continuation onto the left atrial wall. A significantly higher incidence of high-risk DRTs was observed on the Watchman 2.5 device (4.0% [35 of 885]) compared with the Amulet occluder (2.2% [20 of 903]) (P = 0.030). Most low-risk DRTs resolved (12 of 15), whereas high-risk DRTs remained mostly unresolved (34 of 55). Through 5 years, all clinical outcome rates were numerically higher in the high-risk DRT group compared with the low-risk DRT or no-DRT group; significance was observed in the composite of stroke, systemic embolism, or cardiovascular death (30.4% vs 19.9%; HR: 1.74; 95% CI: 1.03-2.92; P = 0.037) and cardiovascular death (26.4% vs 14.5%, HR: 2.09; 95% CI: 1.20-3.66; P = 0.009).

CONCLUSIONS

High-risk DRTs were observed in a higher number of Watchman 2.5 device patients compared with Amulet occluder patients. The composite of stroke, systemic embolism, or cardiovascular death occurred more often in patients with high-risk DRTs compared with those with low-risk DRTs or no DRTs. (AMPLATZER Amulet Left Atrial Appendage Occluder [LAAO] Investigational Device Exemption [Amulet IDE Trial]; NCT02879448).

Step-by-Step ICE-Guided Aspiration Thrombectomy: Gastrointestinal Bleeding Patient With Device-Related Thrombus on Watchman FLX

Objectives

Device-related thrombus (DRT) remains a significant complication in the field of left atrial appendage occlusion (LAAO). In patients who have difficulty tolerating long-term anticoagulation, treatment options are limited. We present a step-by-step intracardiac echocardiography (ICE)-guided AngioVac (AngioDynamics) challenging case in a 71-year-old woman with a gastrointestinal bleeding tendency and a highly mobile thrombus on a Watchman FLX device (Boston Scientific).

Key Steps

We obtained a 26-F DrySeal (Gore Medical) venous access, a 15-F extracorporeal membrane oxygenation cannula arterial access, and a 3-dimensional ICE access. We performed a challenging transseptal crossing using an Agilis medium curl catheter (Abbott) and an electrified Astato wire (Asahi Intecc Medical) as a result of a severely hypertrophic lipomatous septum. We snared the ICE catheter across the interatrial septum (IAS) with a 35-mm gooseneck snare in the inferior vena cava. We used a balloon-assisted technique to bring the F-18 AngioVac system across the IAS. The helicoptering technique with a J-wire assisted with suction of the DRT.

Potential Pitfalls

Currently, there are no data to support which post-LAAO antithrombotic regimen predicts DRT. For patients who are unable to tolerate long-term anticoagulation, treatment options are limited. To our knowledge, this is the first reported ICE-guided LAAO thrombus aspiration.

Take-Home Messages

ICE-guided aspiration thrombectomy of LAAO thrombus is feasible in high-risk patients who cannot tolerate long-term oral anticoagulation and to reduce the risk of clot embolization.

Short- and long-term outcomes of percutaneous left atrial appendage occlusion in cancer patients

Introduction and objectives

Percutaneous left atrial appendage occlusion (LAAO) is a viable option to mitigate bleeding and stroke risks in patients with atrial fibrillation (AF) who are not eligible for oral anticoagulation. Its safety and efficacy in cancer patients remain unclear due to their exclusion from trials. This study aimed to compare short- and long-term LAAO outcomes between cancer and non-cancer patients.

Methods

Retrospective single centre study of 361 consecutive patients who underwent LAAO between april-2010 and december-2023 were included. Short-term outcomes included periprocedural complications, 30-day hospital readmission and mortality. Long-term outcomes included the composite of stroke, bleeding, and mortality and each component assessed separately.

Results

The study included 93 cancer patients (54 % active, 46 % in remission) and 268 non-cancer patients. Baseline characteristics were similar, including ischemic and bleeding risk profiles (CHA2DS2-VASc: 4.5 ± 1.4 vs. 4.4 ± 1.5; HAS-BLED: 3.3 ± 0.9 vs. 3.2 ± 0.9), previous stroke and total bleeding events. Short-term outcomes showed no significant differences in periprocedural complications (7 % vs. 6 %), 30-day readmission (2 % vs. 3 %), or 30-day mortality (0 % vs. 1.5 %). Over 32 months, there was no significant difference regarding the composite endpoint (p = 0.067), stroke (SHR 0.54; p = 0.25) or bleeding events (SHR 1.36; p = 0.35). LAAO was effective in terms of stroke reduction in cancer and non-cancer patients (p = 0.027 and p = 0.006, respectively). All-cause mortality rates were higher in cancer patients (p = 0.002), mainly due to cancer progression and infections.

Conclusions

LAAO procedure was safe and effective in both populations. Cancer patients experienced higher rates of all-cause mortality, with no differences in stroke and bleeding outcomes between groups.

Impact of Angiographically Detected Residual Trabeculation After Left Atrial Appendage Closure Using the WATCHMAN Device: Insight From the OCEAN-LAAC Registry

BACKGROUND

Research on the impact of angiographically detected residual trabeculation after left atrial appendage closure (LAAC) is limited.

OBJECTIVES

To investigate the incidence, characteristics, and clinical implications of angiographically detected residual trabeculation after LAAC using the WATCHMAN device.

METHODS

We analyzed 1350 consecutive patients with atrial fibrillation undergoing LAAC using the WATCHMAN device from the OCEAN-LAAC registry, which is a prospective ongoing, multicenter Japanese registry. The inclusion criteria comprised patients who successfully underwent LAAC and whose presence or absence of residual trabeculation can be confirmed using a contrast medium. The clinical outcomes were compared between patients with and without angiographically detected residual trabeculation.

RESULTS

Residual trabeculation was angiographically detected in 5.6% (75/1350 patients). At the procedure, the proportion of peri-device leak (PDL) was significantly higher in the residual trabeculation group than in the non-residual trabeculation group (20% vs. 5.1%, p < 0.001). However, the PDL and device-related thrombosis at 45 days and 1 year were comparable between the two groups (37% vs. 23%, p = 0.24; 28% vs. 31%, p = 0.84; 2.1% vs. 1.4%, p = 0.50; 6.9% vs. 6.0%, p = 0.69, respectively). The 3-year cumulative incidence of ischemic stroke, all cardiovascular death, and all-cause death were comparable between the two groups (5.7% vs. 5.5%, log-rank p = 0.96; 7.7% vs. 8.9%, log-rank p = 0.34, 31.4% vs. 22.3%, log-rank p = 0.71, respectively).

CONCLUSION

The angiographically detected residual trabeculation rate was 5.6%, and this population had a significantly higher prevalence of PDL at the procedure. However, the presence of residual trabeculation did not contribute to PDL or device-related thrombosis at follow-up or affect the clinical outcomes.

Impact of early bleeding on long-term mortality after left atrial appendage occlusion

BACKGROUND

Short-term antithrombotic therapy is recommended after left atrial appendage occlusion (LAAO) to reduce the risk of device-related thrombosis. However, patients referred for LAAO have excess bleeding risk. Yet, short-term bleeding events post-LAAO are not well characterized.

OBJECTIVES

We aimed to evaluate the incidence of early bleeding post-LAAO and its association with long-term mortality risk. We also sought to identify predictors of early bleeding.

METHODS

Patients who underwent LAAO at Mayo Clinic between 2018 and 2023 were included. Early bleeding was defined as bleeding that occurred within 3 months of discharge. A multivariable Cox proportional hazards model was used to assess the association between early bleeding and death and to estimate the hazard ratio. Multivariable regression analysis was used to identify predictors of early bleeding.

RESULTS

Of the 592 patients included, 389 (66%) were male, and the mean age was 75.6 years. Eighty-three patients (14.0%) experienced early bleeding, with the majority having minimal (63.4%) or minor (17.3%) bleeding. At a median follow-up of 14.4 months (interquartile range 4.2-27.9 months), early bleeding after LAAO was associated with an increased risk of all-cause mortality (adjusted hazard ratio 2.07; 95% confidence interval 1.15-3.75; P = .02). A history of intracranial bleeding, nonparoxysmal atrial fibrillation, CHA2DS2-VASc score, and early device-related thrombosis were independent predictors of early bleeding. Antithrombotic therapy at discharge was not associated with early nonprocedural bleeding.

CONCLUSION

One in 7 patients experience a nonprocedural bleeding event within 90 days of LAAO. Early bleeding after LAAO is associated with a higher all-cause mortality risk during mid-term follow-up. Further studies are needed to optimize the management of patients undergoing LAAO.

Clinical effectiveness and safety comparison between direct oral anticoagulants and warfarin for nonvalvular atrial fibrillation patients following percutaneous left atrial appendage closure operation intervention: a prospective observational study

The main objective of this study was to investigate the optimal post-left atrial appendage closure (LAAC) anticoagulation strategy, focusing on minimizing device-related thrombosis (DRT) and thromboembolism (TE) events without increasing bleeding risk. After successful LAAC, consecutive participants were treated with 45-day anticoagulants (rivaroxaban 15 mg daily, dabigatran 110 mg twice a day, and warfarin). The efficacy endpoints included DRT, TE, and hospital readmissions due to cardiac caused, while safety endpoints encompassed bleeding events, monitored over a 12-month follow-up period. The incidence of DRT was relatively lower in the rivaroxaban group compared to both the dabigatran and warfarin groups (rivaroxaban vs. dabigatran: HR = 0.504, 95% CI 0.208-1.223, log-rank P = 0.101; rivaroxaban vs. warfarin: HR = 0.468, 95% CI 0.167-1.316, log-rank P = 0.093). The median [interquartile range] length and width of DRT in the rivaroxaban group were 1.92 [1.68-2.15] mm and 1.49 [1.28-1.76] mm, both significantly lower than those in the dabigatran (length = 2.15 [1.99-2.25] mm, P = 0.036; width = 1.60 [1.54-1.85] mm, P = 0.035) and warfarin groups (length = 2.26 [2.11-2.44] mm, P = 0.006; width = 1.74 [1.54-1.85] mm, P = 0.006). Kaplan-Meier survival analysis indicated that procedural bleeding was more common in the warfarin group. The 12-month incidence of TE was significantly lower in the rivaroxaban group compared to the dabigatran (HR = 0.466, 95% CI 0.221-0.984, log-rank P = 0.029) and warfarin groups (HR = 0.456, 95% CI 0.188-0.966, log-rank P = 0.042). Long-term antithrombotic therapy with reduced dose of rivaroxaban significantly reduced the risk of DRT and composite endpoints without increasing bleeding events, compared to warfarin and dabigatran, for patients following LAAC.

Left atrial appendage closure guided by fusion of 3D computational modelling on real-time fluoroscopy: A multicenter experience

BACKGROUND

Patient-specific 3-dimensional (3D) computational modelling offers a tailored approach with promising results, but experience using digital-twin fusion on real-time fluoroscopy to guide left atrial appendage closure (LAAC) is unreported.

OBJECTIVES

To assess whether LAAC guided by fusion of a 3D computational model on real-time fluoroscopy is safe and effective.

METHODS

We included retrospectively through a multicenter registry all consecutive patients with non-valvular atrial fibrillation (AF) who underwent LAAC guided by artificial intelligence (AI)-enabled computer simulations (FEops, Gent, Belgium) fusion with real-time fluoroscopy. Operators selected the appropriate device size and position in relation to the LAA using FEops HEARTguide™, and a digital twin was provided for image fusion. The primary efficacy endpoint was successful LAAC with the use of a single device, without moderate or greater peri-device leak and/or device related thrombus (DRT) on follow-up imaging. The primary safety endpoint was a composite of major procedural complications including tamponade, stroke, systemic embolism, major bleeding, and device embolization.

RESULTS

A total of 106 patients underwent LAAC with an Amulet™ or Watchman FLX™ device using CT-model-fluoroscopy fusion imaging. Device implantation was successful in 100 % of cases. The primary efficacy endpoint was met in 82 patients (89 %). A single-device SINGLE-deployment LAAC procedure was observed in 49 cases (46 %). The primary safety endpoint occurred in 2 patients (1.9 %). After a median follow-up of 405 days, two patients suffered an ischemic stroke and four expired.

CONCLUSIONS

Fusion of a CT-based 3D computational model on real-time fluoroscopy is a safe and effective approach that may optimize transcatheter LAAC outcomes.

Reproducibility of cardiac computed tomography classifications of hypoattenuated thickening and peridevice leak following left atrial appendage closure

AIMS

To assess the reproducibility of interpreting hypoattenuated thickening (HAT) and peridevice leak (PDL) using cardiac computed tomography (CT) imaging following Watchman FLX left atrial appendage closure (LAAC).

METHODS AND RESULTS

In this multicentre retrospective reproducibility study, 100 anonymized post-LAAC cardiac CT scans were evaluated within the same cardiac phase by an experienced and a novice rater blinded to prior evaluations. All scans were evaluated twice by each rater, assessing overall HAT and PDL categories as well as specific associated findings based on suggested algorithms for post-LAAC interpretation. Inter- and intra-rater agreement and reliability were evaluated using absolute agreement, Cohen's kappa, and Kendall's tau for categorical variables, and mean difference, Bland-Altman plots, limits of agreement (lower and upper), and intra-class correlation coefficients (ICCs) for continuous variables. Within overall categories of both HAT and PDL, substantial agreement (kappa ≥0.61) and reliability (Kendall's tau-b ≥ 0.75) were observed. Specifically, identifying high-grade HAT (kappa ≥0.78) and distal patency (kappa ≥0.85) displayed the highest agreement within HAT and PDL interpretation. Meanwhile, measuring the height of the proximal screw hub cove represented the least reliable HAT assessment among both inter- and intra-rater comparisons (ICC < 0.75), while suspected leak mechanism represented the least reproducible PDL measure.

CONCLUSION

Despite only minimal training of one rater, overall high levels of inter- and intra-rater agreement and reliability were observed across the chosen algorithms for interpretation of HAT and PDL following Watchman FLX LAAC. The prognostic implications of the included variables are to be explored in future trials and registries.

Impact of intensive versus nonintensive antithrombotic treatment on device-related thrombus after left atrial appendage closure

INTRODUCTION AND OBJECTIVES

The optimal antithrombotic therapy (AT) after left atrial appendage closure (LAAC) is debated. We assessed the impact of intensive vs nonintensive AT on the incidence of device-related thrombus (DRT) based on whether the device implantation was classified as optimal or suboptimal.

METHODS

This study included patients who underwent successful LAAC in 9 centers. Patients were classified according to the quality of device implantation: optimal (proximal implant without ≥3mm peridevice leak) or suboptimal (distal implant and/or ≥3mm peridevice leak). Postimplant AT was classified as either intensive (dual antiplatelet therapy, anticoagulants, or a combination of both) or nonintensive (no AT or a single antiplatelet therapy). The primary endpoint was the incidence of DRT between the 6th and 12th weeks postprocedure.

RESULTS

A total of 1225 patients underwent LAAC, with 757 (61.8%) achieving optimal device implantation and 468 (38.2%) classified as suboptimal. After a median follow-up of 20 months, the incidence of DRT in the optimal implant group was 2.6% with intensive AT and 3.7% with nonintensive AT (P=.38). In the suboptimal implant group, the incidence of DRT increased to 11.2% with intensive AT and 15.5% with nonintensive AT (P=.19). On multivariate analysis, suboptimal implantation (HR, 4.51; 95%CI, 2.70-7.54, P<.001) but not intensive AT (HR, 0,66; 95%CI, 0.40-1.07, P=.09) emerged as an independent predictor of DRT.

CONCLUSIONS

The incidence of DRT after LAAC was higher in patients with suboptimal device implantation. In patients with optimal implantation, the incidence of DRT was low and similar between nonintensive and intensive AT strategies. Large, randomized trials are warranted to confirm these results.

Combined left atrial appendage occlusion and catheter ablation procedure for left atrial arrhythmias: A real-world, propensity-matched analysis

INTRODUCTION

Real-world studies comparing safety and efficacy of combined percutaneous left atrial appendage occlusion (LAAO) and catheter ablation (CA) to LAAO alone are limited.

METHODS

Patients from a large US hospital system undergoing combined LAAO and left-atrial CA from 8/2020 to 2/2024 were retrospectively analyzed and compared to a control group undergoing LAAO alone. Controls were identified using a 1:2 propensity score match based on LAAO device type (Watchman FLX vs. Amulet), CHA2D2-VASc and Hypertension, Abnormal renal/liver function, Stroke, Bleeding history or predisposition, Labile international normalized ratio [INR], Elderly, Drugs/alcohol (HAS-BLED) scores and compared for safety, sealing performance and clinical outcomes at 6 months.

RESULTS

Patients were younger in the combined (n = 72) than in the control group (n = 144, 70.2 ± 7.3 vs. 76.7 ± 6.9 years, p < 0.001) but otherwise comparable with a mean CHA2D2-VASc score of 4.2 ± 1.1 and 4.4 ± 1.2 (p = 0.26) and HAS-BLED score of 2.2 ± 0.8 and 2.3 ± 0.7 (p = 0.34). Successful LAAO implantation rates were the same (95.8% vs. 95.8%, p = 0.99) with longer procedure times seen in the combined group (156.5 ± 53 vs. 56 ± 26 min, p < 0.001). Both major (1.4% vs. 2.1%, p = 0.72) and minor (27.8% vs. 19.4%, p = 0.17) in-hospital complications were similar between the combined and control group, respectively. At 45 days, presence of peri-device leak (18.3% vs. 30.4%, p = 0.07) and device related thrombosis (4.5% vs. 4.5%, p = 0.96) on transesophageal echocardiogram did not differ. Finally, all-cause mortality (0% vs. 1.4%, p = 0.99), thromboembolic (0% vs. 0%, p = 0.99) and bleeding (6.1% vs. 4.4%, p = 0.73) events during follow-up were comparable.

CONCLUSION

This large, real-world analysis indicates comparable safety and efficiency of combined LAAO and CA when compared with LAAO alone.

Advancements in 3D Transoesophageal Echocardiography (TOE) and Computed Tomography (CT) for Stroke Prevention in Left Atrial Appendage Occlusion Interventions

Left atrial appendage occlusion (LAAO) has emerged as a highly effective alternative to oral anticoagulation for stroke prevention in patients with non-valvular atrial fibrillation. Precise pre-procedural planning and meticulous post-procedural follow-up are essential for achieving successful LAAO outcomes. This review explores the latest advancements in three-dimensional (3D) transoesophageal echocardiography (TOE) and computed tomography (CT) imaging modalities, which have considerably improved the planning, intra-procedural guidance, and follow-up processes for LAAO interventions. Innovations in 3D TOE and CT imaging have transformed the approach to LAAO by providing a more detailed and accurate assessment of the left atrial appendage, enabling clinicians to acquire comprehensive anatomical and morphological information, crucial for optimising device selection and positioning, thus reducing the risk of complications and enhancing the overall safety and efficacy of the procedure. Post-procedurally, CT and TOE imaging are invaluable in the monitoring of patients, ensuring that the device is correctly positioned and functioning as intended. Early detection of any complications (e.g., device-related thrombus and peri-device leaks) can help to risk-stratify patient at increased risk of stroke and initiate timely interventions, thereby improving long-term outcomes for patients.

Flow Dynamic Factors Correlated With Device-Related Thrombosis After Left Atrial Appendage Occlusion

Background

Device-related thrombosis (DRT) occurs in up to 4% of patients undergoing left atrial appendage occlusion (LAAO) and is associated with substantial morbidity and mortality. However, its pathophysiology, predictors, and optimal management remain unclear.

Objectives

This study aims to assess flow dynamic factors correlating to DRT.

Methods

A multicenter registry of patients who underwent LAAO and had pre- and post-computed tomography imaging was used. Patient-specific 3-dimensional digital models of the left atrium were created, and finite element simulations were performed to implant an LAAO device into each model in a position that matched the clinical deployment. Computational fluid dynamic simulations were performed to quantify the following flow dynamic parameters: time averaged wall shear stress, oscillatory shear index, and endothelial cell activation potential.

Results

A total of 38 patients (19 with DRT and 19 without DRT) were included. Left atrium volumes and mitral valve areas were larger in the DRT cohort compared with controls. Patients with DRT had a significantly lower time averaged wall shear stress (1.76 ± 1.24 Pa vs 2.90 ± 2.70 Pa), a higher oscillatory shear index (0.19 ± 0.11 vs 0.17 ± 0.11), and a higher endothelial cell activation potential (0.23 ± 0.58 Pa-1 vs 0.17 ± 0.30 Pa-1) than the controls (P < 0.001 for all). Thrombus locations identified from in-vivo images correlated well with the flow dynamic parameters tested.

Conclusions

Flow dynamic parameters may be able to predict the risk of DRT after LAAO. Further investigation with a larger patient cohort and long-term follow-up is needed to assess the role of computational fluid dynamics in the risk stratification of patients considered for LAAO.

Correlations Between Plasma BNP Level and Risk of Thrombotic-Hemorrhagic Events After Left Atrial Appendage Closure

Background: Percutaneous left atrial appendage closure (LAAC) reduces the incidence of stroke/bleeding events in patients with non-valvular atrial fibrillation, high risk of stroke, and contraindication in continuing anticoagulation therapy. Of them, patients with heart failure may remain at high risk of these events after LAAC. Method: Patients who underwent LAAC and were listed for the multi-center, prospectively collected OCEAN-LAAC registry, were eligible. Of them, individuals without baseline plasma B-type natriuretic peptide (BNP) levels and those dependent on hemodialysis were excluded. The prognostic impact of baseline plasma BNP levels on the incidence of death or stroke/bleeding events after LAAC was evaluated. Results: A total of 937 patients (median 78 years, 596 men) were included. The LAAC device was successfully implanted in 934 (98%) patients. Over the 366 (251, 436) days after the LAAC, 148 patients encountered a primary outcome. The common logarithm of baseline plasma BNP was independently associated with the primary outcome with an adjusted hazard ratio of 1.46 (95% confidence interval 1.06-2.18, p = 0.043). A calculated cutoff of 2.12 (equivalent to 133 pg/mL of plasma BNP level) significantly stratified the cumulative incidence of the primary outcome (29% vs. 21% for 2 years, p = 0.004). Conclusions: Using prospectively collected large-scale multi-center Japanese registry data, we demonstrated that a baseline higher plasma BNP level was independently associated with a higher incidence of stroke/bleeding events and mortality after LAAC. Further studies are warranted to understand the optimal therapeutic strategy for LAAC candidates with elevated baseline plasma BNP levels.

Antithrombotic therapy for transcatheter structural heart intervention

Percutaneous transcatheter structural heart interventions have considerably expanded within the last two decades, improving clinical outcomes and quality of life versus guideline-directed medical therapy for patients frequently ineligible for surgical treatment. Transcatheter structural heart interventions comprise valve implantation or repair and also occlusions of the patent foramen ovale, atrial septal defects and left atrial appendage. These procedures expose structural devices to arterial or venous blood flow with various rheological conditions leading to potential thrombotic complications and embolisation. Furthermore, these procedures may concern comorbid patients at high risk of both ischaemic and bleeding complications. This state-of-the-art review provides a description of the device-related thrombotic risk associated with these transcatheter structural heart interventions and of the current evidence-based guidelines regarding antithrombotic treatments. Gaps in evidence for each of the studied transcatheter interventions and the main ongoing trials are also summarised.

Position Statement on Cardiac Computed Tomography Following Left Atrial Appendage Occlusion

Left atrial appendage occlusion (LAAO) is rapidly growing as valid stroke prevention therapy in atrial fibrillation. Cardiac imaging plays an instrumental role in preprocedural planning, procedural execution, and postprocedural follow-up. Recently, cardiac computed tomography (CCT) has made significant advancements, resulting in increasing use both preprocedurally and in outpatient follow-up. It provides a noninvasive, high-resolution alternative to the current standard, transesophageal echocardiography, and may display advantages in both the detection and characterization of device-specific complications, such as peridevice leak and device-related thrombosis. The implementation of CCT in the follow-up after LAAO has identified new findings such as hypoattenuated thickening on the atrial device surface and left atrial appendage contrast patency, which are not readily assessable on transesophageal echocardiography. Currently, there is a lack of standardization for acquisition and interpretation of images and consensus on definitions of essential findings on CCT in the postprocedural phase. This paper intends to provide a practical and standardized approach to both acquisition and interpretation of CCT after LAAO based on a comprehensive review of the literature and expert consensus among European and North American interventional and imaging specialists.

Watchman vs. Amulet for Left Atrial Appendage Closure: Current Evidence and Future Perspectives

Left atrial appendage closure (LAAC) is a crucial intervention for stroke prevention in patients with non-valvular atrial fibrillation who are unsuitable for long-term anticoagulation. Amulet and Watchman are the most implanted devices worldwide for performing LAAC, and the aim of this review is to provide a comprehensive comparison focusing on their efficacy, safety, and short- and long-term outcomes. The Watchman device, the first to gain FDA approval, has been extensively studied and demonstrates significant reductions in stroke and systemic embolism rates. The Amulet device, a newer alternative, promises enhanced design features for more efficient appendage sealing. Current data highlight that both devices offer similar efficacy and safety for LAAC. While the two devices differ in terms of intraprocedural complication rates, they offer similar short- to long-term outcomes in terms of peri-device leaks, device-related thrombosis, and mortality. Both devices are indicated for patients who are unable to tolerate OAC, given their similar risk and safety profiles. Newer clinical studies are directed at establishing the efficacy of both devices as the primary method for stroke prevention in AF as an alternative to OAC.

Transition from WATCHMAN generation-2.5 device to WATCHMAN FLX device for percutaneous left atrial appendage closure: Incidence and predictors of device-related thrombosis and short- to mid-term outcomes

BACKGROUND

Patients with nonvalvular atrial fibrillation (AF) not suitable for long-term anticoagulant therapy undergo percutaneous left atrial appendage closure (LAAC) using the WATCHMAN device. The safety and efficacy of WATCHMAN-FLX (WM-FLX) compared with WATCHMAN-2.5 (WM-2.5), particularly in Asian populations, is unknown.

METHODS

We evaluated the background, procedure, and clinical outcomes of 199 patients who underwent LAAC between September 2019 and December 2022 and compared WM-2.5 (72 patients) with WM-FLX (127 patients).

RESULTS

The mean age was 76 years, with 128 men, and 100 had nonparoxysmal AF (non-PAF). The mean CHA2DS2-VASc, and HAS-BLED were 5.1, and 3.2 points, respectively. WM-FLX group demonstrated a shorter procedure time than WM-2.5 group (50 vs. 42 min, p = 0.001). The WM-FLX group demonstrated no procedural-related acute cardiac tamponade, which was significantly low (5.6% vs. 0%, p = 0.02), and a significantly higher rate of complete seal at 45-day (63% vs. 80%, p = 0.04). WM-FLX group had a significantly higher cumulative 1-year incidence of device-related thrombosis (DRT) than WM-2.5 group (3.4% vs. 7.0%, Log-rank p = 0.01). Univariate analysis identified two DRT risk factors in the WM-FLX group: non-PAF (odds ratio [OR] 7.72; 95% confidence interval [CI] 1.20-48.7; p = 0.04), and 35-mm device (OR 5.13; 95% CI 1.31-19.8; p = 0.02).

CONCLUSIONS

WM-FLX significantly improved the procedural quality and safety of LAAC. However, DRT remains an important issue even in the novel LAAC device, being a hazard for patients with high DRT risk, such as having non-PAF and using 35-mm devices.

The correlation between ultrasonographic morphology and structure of the left atrial appendage, blood flow velocity, and plasma galectin-3 levels with thrombus formation in the left atrial appendage of patients with atrial fibrillation

Background

To explore the correlation between left atrial appendage morphology, blood flow velocity and plasma galectin-3 and thrombosis in patients with atrial fibrillation.

Methods

Patients with atrial fibrillation who received treatment and completed ultrasound examination in hospital from 2022 to December 2023 were enrolled. According to whether there was left atrial appendage thrombosis, the patients were divided into a control group (no left atrial appendage thrombosis was found) and a study group (left atrial appendage thrombosis was found). The morphology and structure of the left atrial appendage, blood flow velocity and plasma galectin-3 level were recorded exploring its correlation with left atrium thrombosis.

Results

A total of 330 patients with atrial fibrillation were enrolled, including 278 in the control group and 52 in the study group. Left group and the control group of morphological structure differences (P < 0.05). The main lobe length, ostial area, longest diameter, shortest diameter, left atrial appendage volume and left atrial volume in the study group were higher than those in the control group (P < 0.05). The left atrial appendage emptying velocity, filling velocity and left ventricular ejection fraction of the study group were lower than those of the control group, and the left ventricular end-diastolic diameter was higher than that of the control group (P < 0.05). Group of white blood cell count, neutrophils/lymphocyte ratio, plasma galactose lectin-3 levels were higher than control group (P < 0.05). ROC curve analysis of left atrial appendage emptying velocity, left atrial appendage filling velocity, left atrial enddiastolic diameter and left atrial ejection fraction had higher diagnostic value (P < 0.05).

Conclusions

Left atrial appendage morphology, blood flow velocity and plasma galectin-3 level are important factors to evaluate the risk of left atrial appendage thrombosis in patients with atrial fibrillation. This study improves the understanding of thrombosis, further elucidates the risk factors for thrombosis, and improves patient prognosis.

Ischemic stroke associated with high-grade pedunculated device-related thrombosis following left atrial appendage closure

We have seen ischemic stroke associated with a high-grade device-related pedunculated thrombosis after left atrial appendage closure (LAAC) after discontinuation of oral anticoagulations (OACs). Continuation of OACs, including half-dose direct oral anticoagulations after LAAC, may be a better option for patients at high risk of thromboembolism to prevent further thromboembolic events.

Unforeseen and Immediate: A Case of a Post-Watchman Device-Related Thrombus

Atrial fibrillation (AFib) is recognized as a risk factor linked to arterial thromboembolism stemming from blood clot formation in the left atrium, associated with increased morbidity and mortality. Most of these thrombi originate in the left atrial appendage (LAA). Oral anticoagulation (OAC) therapy can help mitigate this risk. LAA occlusion (LAAO) has emerged as an option for patients who cannot safely tolerate long-term OAC. Watchman is one of the commonly used devices with a favorable safety profile demonstrated in numerous studies. One of the most concerning complications of LAAO is device-related thrombus (DRT), which may form on the atrial side of the device and potentially lead to embolization. We present a rare case of immediate DRT formation following the deployment of a Watchman device in a 78-year-old male with persistent AFib. Despite appropriate periprocedural management, a thrombus was observed immediately post implantation. This case emphasizes the need for vigilant surveillance, prompt diagnosis, and therapeutic intervention to manage such complications. The patient was successfully managed with a heparin drip, leading to thrombus resolution. This report underscores the complexities of managing DRT and the importance of ongoing research to optimize outcomes for patients undergoing LAAO.