Incidence, Characterization, and Clinical Impact of Device-Related Thrombus Following Left Atrial Appendage Occlusion in the Prospective Global AMPLATZER Amulet Observational Study

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.

Single versus dual antiplatelet therapy following percutaneous left atrial appendage closure-A systematic review and meta-analysis

BACKGROUND

In the last few years, percutaneous LAA occlusion (LAAO) has become a plausible alternative in atrial fibrillation (AF) patients with contraindications to anticoagulation therapy. Nevertheless, the optimal antiplatelet strategy following percutaneous LAAO remains to be defined.

METHODS

Studies comparing single antiplatelet therapy (SAPT) versus dual antiplatelet therapy (DAPT) following LAAO were systematically searched and screened. The outcomes of interest were ischemic stroke, device-related thrombus (DRT) and major bleeding. A random-effect meta-analysis was performed comparing outcomes in both groups. The moderator effect of baseline characteristics on outcomes was evaluated by univariate meta-regression analyses.

RESULTS

Sixteen observational studies with 3255 patients treated with antiplatelet therapy (SAPT, n = 1033; DAPT, n = 2222) after LAAO were included. Mean age was 74.5 ± 8.3 years, mean CHA2DS2-VASc and HAS-BLED scores were 4.3 ± 1.5 and 3.2 ± 1.0, respectively. At a weighted mean follow-up of 12.7 months, the occurrence of stroke (RR 1.33; 95% CI 0.64-2.77; p =.44), DRT (RR 1.52; 95% CI 0.90-2.58; p =.12), and the composite of stroke and DRT (RR 1.26; 95% CI 0.67-2.37; p =.47) did not differ significantly between SAPT and DAPT groups. The rate of major bleedings was also not different between groups (RR 1.41; 95% CI 0.64-3.12; p =.39).

CONCLUSIONS

Among AF patients at high bleeding risk undergoing percutaneous LAAO, a post-procedural minimalistic antiplatelet strategy with SAPT did not significantly differ from DAPT regimens regarding the rate of stroke, DRT and major bleeding.

Challenges and advances in device-related thrombus in left atrial appendage occlusion

Oral anticoagulation therapy (OAC) is a mainstay for mitigating stroke and other embolic events in patients with atrial fibrillation (AF). Despite the demonstrated efficacy of OAC in reducing events, many patients are unable to tolerate OAC due to bleeding risks. Left atrial appendage occlusion (LAAO) devices were developed as implantable technologies to moderate stroke risk in patients with intolerance to OAC. Despite clinical data supporting near-comparable protection against thromboembolic events with OAC, device-related thrombus formation has emerged as a critical complication following LAAO that remains a potential limitation to the safety and efficacy of LAAO. Improved biocompatibility of LAAO devices with fluoropolymers, a well-established stent-coating technology used to reduce thrombus formation and promote endothelialization, may optimize outcomes after LAAO.

Combining catheter ablation and left atrial appendage occlusion in high-risk patients with atrial fibrillation: a propensity score-matched analysis

BACKGROUND

The safety and efficacy of a combined approach of catheter ablation (CA) and left atrial appendage occlusion (LAAO) compared to LAAO alone remain unknown.

METHODS

Patients with atrial fibrillation (AF) at increased stroke risk who underwent LAAO were divided into either combined (CA and LAAO) procedures or LAAO alone group. Propensity score matching was utilized to balance baseline characteristics. The primary endpoint of the study was a composite of death, thromboembolic events, major bleeding, heart failure (HF) rehospitalization, and major periprocedural complications.

RESULTS

A total of 707 AF patients who underwent LAAO were included. After 1:1 propensity score matching, 166 patients who underwent LAAO alone (n = 83) or the combined procedure (n = 83) were analyzed. Successful LAAO was achieved in all (100%) patients, with a low incidence of periprocedural complications in both groups (2.4% vs. 4.8%, LAAO vs. combined, p = 0.68). The incidence of peri-device leak post-LAAO was significantly higher in the combined group (25.3% vs. 43.4%, p = 0.01). After a median follow-up of 2 years, there were no significant differences in the rates of the primary composite endpoint between the two strategies (22.2% vs. 14.3%, HR: 1.24 [95% CI: 0.51-2.97], p = 0.63). However, the rate of HF rehospitalization was significantly lower in the combined group (19.6% vs. 3.6%, HR: 4.89 [95% CI: 1.50-15.97], p = 0.024).

CONCLUSIONS

Combining CA and LAAO in a "one-stop" approach is safe and brings additional benefits in relieving symptoms of heart failure, although peri-device leak was more common compared to LAAO alone.

Single antiplatelet therapy following Amplatzer left atrial appendage occlusion

BACKGROUND

The optimal antithrombotic therapy following left atrial appendage occlusion (LAAO) remains debated. Ideally, this therapy should effectively prevent device-related thrombosis (DRT) while minimising the associated bleeding risk.

AIMS

We aimed to evaluate the long-term safety and efficacy of a postprocedural single antiplatelet therapy (SAPT) strategy following Amplatzer LAAO in a large consecutive cohort.

METHODS

This retrospective, single-centre, observational study included all patients discharged on SAPT after LAAO with the Amplatzer Cardiac Plug (ACP) or Amplatzer Amulet between March 2010 and December 2021 at Aarhus University Hospital, Denmark. Baseline, procedural, and imaging data were obtained locally, while clinical outcomes and medication data were extracted from the Danish national health registries.

RESULTS

A total of 553 patients underwent Amplatzer LAAO during the specified time frame. Of these, 431 (77.9%) high bleeding risk patients were discharged on SAPT with either acetylsalicylic acid (n=403, 72.9%) or clopidogrel (n=28, 5.1%). At 6 months, 173 (41.7%) patients were not on any antithrombotic therapy. The mean CHA2DS2-VASc and HAS-BLED scores were 3.9±1.5 and 3.4±1.1, respectively. DRT was detected in 6 (1.5%) patients on 8-week follow-up imaging using cardiac computed tomography (n=386, 89.6%) or transoesophageal echocardiography (n=27, 6.3%). The 1-year ischaemic stroke rate was 2.2% (95% confidence interval [CI]: 1.1-4.2). One-year rates for major bleeding and cardiovascular death were 5.9% (95% CI: 4.0-8.9) and 2.9% (95% CI: 1.6-5.1), respectively.

CONCLUSIONS

SAPT following Amplatzer LAAO displayed rates of DRT and stroke comparable to those reported with more intensive antithrombotic regimens. Meanwhile, we observed low rates of major bleeding.

Left Atrial Appendage Occlusion and Post-procedural Antithrombotic Management

Left atrial appendage occlusion (LAAO) is an established alternative to oral anticoagulation for stroke prevention in atrial fibrillation. Antithrombotic therapy is used in the post-procedural period to prevent device-related thrombosis (DRT). The risk of DRT is considered highest in the first 45-90 days after device implantation, based on animal studies of the device healing process. Clinically applied antithrombotic regimens vary greatly across studies, continents, and centers. This article gives an overview of the evidence behind current antithrombotic regimens, ongoing randomized trials, and future post-procedural management.

Symptomatic vs. non-symptomatic device-related thrombus after LAAC: a sub-analysis from the multicenter EUROC-DRT registry

BACKGROUND

Device-related thrombus (DRT) after left atrial appendage closure (LAAC) is associated with adverse outcomes, i.e. ischemic stroke or systemic embolism (SE). Data on predictors of stroke/SE in the context of DRT are limited.

AIMS

This study aimed to identify predisposing factors for stroke/SE in DRT patients. In addition, the temporal connection of stroke/SE to DRT diagnosis was analyzed.

METHODS

The EUROC-DRT registry included 176 patients, in whom DRT after LAAC were diagnosed. Patients with symptomatic DRT, defined as stroke/SE in the context of DRT diagnosis, were compared against patients with non-symptomatic DRT. Baseline characteristics, anti-thrombotic regimens, device position, and timing of stroke/SE were compared.

RESULTS

Stroke/SE occurred in 25/176 (14.2%) patients diagnosed with DRT (symptomatic DRT). Stroke/SE occurred after a median of 198 days (IQR 37-558) after LAAC. In 45.8% stroke/SE occurred within one month before/after DRT diagnosis (DRT-related stroke). Patients with symptomatic DRT had lower left ventricular ejection fractions (50.0 ± 9.1% vs. 54.2 ± 11.0%, p = 0.03) and higher rates of non-paroxysmal atrial fibrillation (84.0% vs. 64.9%, p = 0.06). Other baseline parameters and device positions were not different. Most ischemic events occurred among patients with single antiplatelet therapy (50%), however, stroke/SE was also observed under dual antiplatelet therapy (25%) or oral anticoagulation (20%).

CONCLUSION

Stroke/SE are documented in 14.2% and occur both in close temporal relation to the DRT finding and chronologically independently therefrom. Identification of risk factors remains cumbersome, putting all DRT patients at substantial risk for stroke/SE. Further studies are necessary to minimize the risk of DRT and ischemic events.

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

Despite the unprecedented advances in the left atrial appendage occlusion field, device-related thrombus (DRT) remains an unresolved issue with the therapy. This paper aims to provide a state-of-the-art review of the literature on the incidence, clinical impact, predictors and management of DRT and propose a novel classification of DRT and hypoattenuated thickening.

Impact of Device Implant Depth After Left Atrial Appendage Occlusion

BACKGROUND

Device-related thrombus (DRT) remains one of the main concerns after left atrial appendage occlusion (LAAO). Several risk factors have been proposed, but most cannot be modulated. A modifiable factor such as device implantation depth is a potential target to adjust the risk for DRT.

OBJECTIVES

The aim of this study was to assess the impact of LAAO device implantation depth as a predisposing factor for DRT.

METHODS

The study included patients who underwent successful LAAO at 9 centers in Europe and Canada. Patients were classified into 2 groups: proximal device implantation (covered pulmonary ridge [PR] in the lobe and disc cohort or <5 mm from the PR in the single-lobe cohort) and distal device implantation (uncovered PR in the disc and lobe cohort and ≥5 mm in the single-lobe cohort).

RESULTS

A total of 1,317 patients were included. Among these, proximal and distal device implantation was achieved in 732 (55%) and 585 (45%) patients, respectively. No differences in procedural outcomes were observed between the groups. At follow-up, patients with proximal implantation had a lower incidence of DRT (2.3%) than those with distal implantation (12.2%) (P < 0.001). Deeper device implantation and a larger uncovered left atrial appendage area were associated with a higher incidence of DRT (P < 0.001), regardless of device type. In multivariable analysis, distal implant (HR: 5.92; 95% CI: 3.39-10.36) and no or single antiplatelet therapy (HR: 1.62; 95% CI: 0.99-2.62) emerged as independent predictors of DRT.

CONCLUSIONS

LAAO device implantation depth is an independent risk factor for DRT. Deeper device implantation and larger uncovered left atrial appendage areas were associated with a higher incidence of DRT.

3-Year Outcomes From the Amplatzer Amulet Left Atrial Appendage Occluder Randomized Controlled Trial (Amulet IDE)

BACKGROUND

The Amulet (Abbott) left atrial appendage occluder investigational device exemption trial is the largest randomized trial evaluating the safety and effectiveness of the Amulet left atrial appendage occluder compared with the Watchman 2.5 device (Boston Scientific) through 5 years.

OBJECTIVES

This analysis evaluated the device effect on 3-year outcomes in the Amulet investigational device exemption trial.

METHODS

The medication regimen and key clinical outcomes were reported through 3 years including: 1) the composite of ischemic stroke or systemic embolism (SE); 2) the composite of all strokes, SE, or cardiovascular (CV) death; 3) major bleeding; and 4) all-cause death and CV death.

RESULTS

A total of 1,878 patients at 108 sites were randomized. A significantly higher percentage of patients were free of oral anticoagulation usage at 3 years with Amulet (96.2%) vs Watchman (92.5%) (P < 0.01). Clinical outcomes were comparable for the composite of ischemic stroke or SE (5.0% vs 4.6%; P = 0.69); the composite of all strokes, SE, or CV death (11.1% vs 12.7%; P = 0.31); major bleeding (16.1% vs 14.7%; P = 0.46); all-cause death (14.6% vs 17.9%; P = 0.08); and CV death (6.6% vs 8.5%; P = 0.14) for Amulet and Watchman, respectively. Through 3 years, device factors (device-related thrombus or peridevice leak ≥3 mm) preceded ischemic stroke events and CV deaths more frequently in Watchman compared with Amulet patients.

CONCLUSIONS

The Amulet occluder demonstrated continued safety and effectiveness with over 96% free of oral anticoagulation usage through 3 years in a high-risk population compared to the Watchman device. (AMPLATZER Amulet LAA Occluder Trial [Amulet IDE]; NCT02879448).

Left Atrial Appendage Occlusion Under Miniaturized Transesophageal Echocardiographic Guidance and Conscious Sedation: Multicenter European Experience

BACKGROUND

Left atrial appendage occlusion (LAAO) procedures are widely guided by standard transesophageal echocardiography (TEE) probes, requiring general anesthesia in most patients. The use of miniaturized TEE probes allows for LAAO guidance under local anesthesia and offers an attractive imaging alternative to standard TEE probes.

OBJECTIVES

The aim of this study was to assess the safety and efficacy of miniaturized TEE probes for procedural guidance of LAAO.

METHODS

Multicenter retrospective observational study of LAAO procedures performed under miniaturized TEE guidance and conscious sedation. The primary efficacy endpoint was technical success. The secondary efficacy endpoint was procedural success (technical success without major periprocedural complications). The safety outcome was a composite of major periprocedural complications.

RESULTS

A total of 546 consecutive LAAO procedures were performed in 5 European centers. Technical success was achieved in 534 (98.0%) patients. Sixteen major periprocedural complications occurred in 15 (2.9%) patients, yielding a procedural success rate of 97.0%. Conversion to general anesthesia was required in 4 (0.7%) patients. Short-term imaging follow-up was available in 422 patients with an incidence of major (>5 mm) TEE-detected residual leaks of 0.7%, complete LAA occlusion of 82.2% on cardiac computed tomography, and device-related thrombus of 5%. As compared with procedural 2-dimensional imaging for device sizing, preprocedural assessment by 3-dimensional imaging resulted in improved technical success (100% vs 95.0%; P < 0.001).

CONCLUSIONS

LAAO under conscious sedation and miniaturized TEE guidance is safe and feasible with a high rate of technical success and a low rate of periprocedural complications.

Mechanisms, predictors, and evolution of severe peri-device leaks with two different left atrial appendage occluders

AIMS

Incomplete left atrial appendage occlusion (LAAO) due to peri-device leak (PDL) is a limitation of the therapy. The Amulet IDE trial is the largest randomized head-to-head trial comparing the Amulet and Watchman 2.5 LAAO devices with fundamentally different designs. The predictors and mechanistic factors impacting differences in PDLs within the Amulet IDE trial are assessed in the current analysis.

METHODS AND RESULTS

An independent core lab analysed all images for the presence or absence of severe PDL (>5 mm). The incidence, mechanistic factors, predictors using propensity score-matched controls, and evolution of severe PDLs through 18 months were assessed. Of the 1878 patients randomized in the trial, the Amulet occluder had significantly fewer severe PDLs than the Watchman device at 45 days (1.1 vs. 3.2%, P < 0.001) and 12 months (0.1 vs. 1.1%, P < 0.001). Off-axis deployment or missed lobes were leading mechanistic PDL factors in each device group. Larger left atrial appendage (LAA) dimensions including orifice diameter, landing zone diameter, and depth predicted severe PDL with the Watchman device, with no significant anatomical limitations noted with the Amulet occluder. Procedural and device implant predictors were found with the Amulet occluder attributed to the learning curve with the device. A majority of Watchman device severe PDLs did not resolve over time through 18 months.

CONCLUSION

The dual-occlusive Amplatzer Amulet LAA occluder provided improved LAA closure compared with the Watchman 2.5 device. Predictors and temporal observations of severe PDLs were identified in the Amulet IDE trial.

CLINICAL TRIAL REGISTRATION

https://clinicaltrials.gov Unique identifier NCT02879448.

Peri- and Post-procedural Anticoagulation with Left Atrial Appendage Occlusion Devices

In patients with atrial fibrillation and high stroke risk, anticoagulation with direct oral anticoagulants or vitamin K antagonists is the standard of care for stroke prevention. The benefit of anticoagulation is driven by attenuating the risk of thrombus formation in the left atrial appendage. Percutaneous left atrial appendage occlusion offers an alternative therapeutic strategy for stroke prevention in patients with high bleeding risk or contraindications for long-term anticoagulation. This review of the current literature delineates the standard protocols of peri- and post-procedural anticoagulation/antithrombotic therapy after left atrial appendage occlusion, the complications of the procedure, and the risk of device-related thrombosis and of incomplete occlusion of the appendage. Finally,the limitations and gaps in the literature are identified.

Impact of left atrial appendage occlusion device position on potential determinants of device-related thrombus: a patient-specific in silico study

BACKGROUND

Device-related thrombus (DRT) after left atrial appendage occlusion (LAAO) is potentially linked to adverse events. Although clinical reports suggest an effect of the device type and position on the DRT risk, in-depth studies of its mechanistic basis are needed. This in silico study aimed to assess the impact of the position of non-pacifier (Watchman) and pacifier (Amulet) LAAO devices on surrogate markers of DRT risk.

METHODS

The LAAO devices were modeled with precise geometry and virtually implanted in different positions into a patient-specific left atrium. Using computational fluid dynamics, the following values were quantified: residual blood, wall shear stress (WSS) and endothelial cell activation potential (ECAP).

RESULTS

In comparison to an ostium-fitted device position, deep implantation led to more residual blood, lower average WSS and higher ECAP surrounding the device, especially on the device's atrial surface and the surrounding tissue, suggesting increased risk for potential thrombus. For the non-pacifier device, an off-axis device orientation resulted in even more residual blood, higher ECAP and similar average WSS as compared to an ostium-fitted device position. Overall, the pacifier device showed less residual blood, higher average WSS and lower ECAP, compared to the non-pacifier device.

CONCLUSIONS

In this in silico study, both LAAO device type and implant position showed an impact on potential markers of DRT in terms of blood stasis, platelet adhesion and endothelial dysfunction. Our results present a mechanistic basis for clinically observed risk factors of DRT and the proposed in silico model may aid in the optimization of device development and procedural aspects.

The Future of LAAC-In 5, 10, and 20 Years

Early experience with percutaneous LAA closure documented complication rates of ∼10%, with failure to implant devices in ∼10% of patients. These numbers are unrecognizable in contemporary practice due to the iterative changes made largely in the last 10 years. Here we look forward to ask what might change, and when, to bring percutaneous LAA closure out of the niche early adopter centers into routine use. We consider the opportunity to incorporate different technologies into LAAc devices in the context of managing patient with atrial fibrillation. Finally, we consider how to make the procedure safer and more effective.

The Strengths and Weaknesses of the LAA Covering Disc Occluders-Conceptually and in Practice

Endocardial left atrial appendage (LAA) occluders with a covering disc encompass a wide range of devices that share the common feature of a distal anchoring "body" and proximal covering "disc" design. This unique design feature has potential advantages in certain complex LAA anatomies and challenging clinical scenarios. The current review article summarizes the different features of established and novel devices, preprocedural imaging updates, intraprocedural technical considerations, and postprocedural follow-up issues specific to this category of LAA occluders.

Antithrombotic Management After Left Atrial Appendage Closure: Current Evidence and Future Perspectives

Left atrial appendage closure is an alternative to chronic oral anticoagulation to prevent embolic events related to nonvalvular atrial fibrillation. After device implantation, antithrombotic treatment is prescribed to prevent device-related thrombosis, a dreadful complication associated with an increased risk of ischemic events. However, the optimal antithrombotic treatment after left atrial appendage closure, effective on both device-related thrombus prevention and bleeding risk mitigation, remains to be determined. In more than 10 years experience with left atrial appendage closure, a wide range of antithrombotic treatments have been used, mostly in observational studies. In this review, we analyzed the body of evidence for each antithrombotic regimen after left atrial appendage closure to provide tools to guide the physician choice and describe future perspectives in the field.

Impact of Computational Modeling on Transcatheter Left Atrial Appendage Closure Efficiency and Outcomes

BACKGROUND

When performing transcatheter left atrial appendage (LAA) closure, peridevice leaks and device-related thrombus (DRT) have been associated with worse clinical outcomes-hence, their risk should be mitigated.

OBJECTIVES

The authors sought to assess whether use of preprocedural computational modeling impacts procedural efficiency and outcomes of transcatheter LAA closure.

METHODS

The PREDICT-LAA trial (NCT04180605) is a prospective, multicenter, randomized trial in which 200 patients were 1:1 randomized to standard planning vs cardiac computed tomography (CT) simulation-based planning of LAA closure with Amplatzer Amulet. The artificial intelligence-enabled CT-based anatomical analyses and computer simulations were provided by FEops (Belgium).

RESULTS

All patients had a preprocedural cardiac CT, 197 patients underwent LAA closure, and 181 of these patients had a postprocedural CT scan (standard, n = 91; CT + simulation, n = 90). The composite primary endpoint, defined as contrast leakage distal of the Amulet lobe and/or presence of DRT, was observed in 41.8% in the standard group vs 28.9% in the CT + simulation group (relative risk [RR]: 0.69; 95% CI: 0.46-1.04; P = 0.08). Complete LAA closure with no residual leak and no disc retraction into the LAA was observed in 44.0% vs 61.1%, respectively (RR: 1.44; 95% CI: 1.05-1.98; P = 0.03). In addition, use of computer simulations resulted in improved procedural efficiency with use of fewer Amulet devices (103 vs 118; P < 0.001) and fewer device repositionings (104 vs 195; P < 0.001) in the CT + simulation group.

CONCLUSIONS

The PREDICT-LAA trial demonstrates the possible added value of artificial intelligence-enabled, CT-based computational modeling when planning for transcatheter LAA closure, leading to improved procedural efficiency and a trend toward better procedural outcomes.

Diagnostic value of real-time four-dimensional transesophageal echocardiography on the implant-related thrombus

Objectives

This study aims to evaluate the diagnostic value of real-time four-dimensional transesophageal echocardiography (RT4D-TEE) for implant-related thrombus (IRT).

Methods

We collected 1,125 patients with atrial fibrillation from May 2019 to February 2022 in our hospital. All patients accepted transesophageal echocardiography (TEE) examination to exclude any thrombi before the LAAC procedure.

Results

There were 760 patients with LAAC, 66 patients with CIED, and 299 patients without any implantations. A total of 40 patients with an established diagnosis of IRT were further analyzed. The accurate detection rate of IRT by RT4D-TEE was 4.8% (40/826), which was higher than 3.8% (31/826) by 2D-TEE (P = 0.004). No IRT was found on TEE in the rest of the 786 patients. These 40 patients were divided into LAAC (n = 23) and CIED (n = 17) groups according to the results of RT4D-TEE. In the LAAC group, IRT distributed on different parts of the LAA occluder surface, 91.3% (21/23) with clumps of thrombi, and 8.7% (2/23) with a thin layer of thrombi covering the surface of the occluder. In the CIED group, thrombi were seen attached to the leads in the right atrium and right ventricle. The thrombi were beaded in 17.6% (3/17), corded in 17.6% (3/17), and clotted in the remaining 64.7% (11/17) of cases. After adjusting the anticoagulant dosage and following up for 6 months, 20% (8/40) of cases were successfully resolved, 67.5% (27/40) became smaller, and 12.5% (5/40) showed no changes.

Conclusion

The accurate detection rate of IRT by RT4D-TEE was significantly higher than that by 2D-TEE. 2D-TEE has limitations, but RT4D-TEE can be used as an effective complementary method. Imaging and some clinical features differ significantly between IRT on occluder and IRT on CIED lead.

Incidence, Predictors, and Clinical Outcomes of Device-Related Thrombus in the Amulet IDE Trial

BACKGROUND

Device-related thrombus (DRT) following left atrial appendage occlusion (LAAO) can lead to adverse clinical outcomes. DRT rates and outcomes from randomized trials are limited.

OBJECTIVES

This analysis investigated the incidence, predictors, and clinical outcomes of DRT following LAAO in the Amulet IDE (AMPLATZER Amulet LAA Occluder Trial) trial.

METHODS

Successful implants occurred in 903 patients with an Amulet occluder (dual occlusive mechanism device) and 885 patients with a Watchman device (single occlusive mechanism device). These patients were then followed through 18 months and DRT was assessed by transesophageal echocardiography.

RESULTS

The overall incidence of DRT was 3.9% (n = 70) with 3.4% (n = 30) in dual occlusive mechanism device patients and 4.8% (n = 40) in single occlusive mechanism device patients. Most DRTs (n = 19 of 31) were identified early (≤45 days) on the dual occlusive mechanism device, whereas most of the DRTs (n = 31 of 42) were identified late (>45 days) on the single occlusive mechanism device. Strong predictors of DRT included atrial fibrillation at time of procedure (HR: 2.44; 95% CI: 1.42-4.22; P < 0.01), female sex (HR: 1.65; 95% CI: 1.01-2.71; P = 0.04), and older age (HR: 1.04; 95% CI: 1.01-1.08; P = 0.02). There were no stroke events following DRT in the dual occlusive mechanism device group and 3 stroke events following DRT in the single occlusive mechanism device group. Patients with DRT were at a greater risk for cardiovascular mortality compared with non-DRT patients (8.7% vs 3.9%; HR: 2.33; 95% CI: 1.01-5.39; P = 0.04).

CONCLUSIONS

Incidence of DRT following LAAO was low. Early DRTs are seen with the dual occlusive mechanism device and late DRTs are seen with the single occlusive mechanism device. Increased cardiovascular mortality risk in patients with DRT should be further investigated. (AMPLATZER Amulet LAA Occluder Trial; NCT02879448).

Preliminary findings on left atrial appendage occlusion simulations applying different endocardial devices

Atrial fibrillation (AF) is one of the most investigated arrhythmias since it is associated with a five-fold increase in the risk of strokes. Left atrium dilation and unbalanced and irregular contraction caused by AF favour blood stasis and, consequently, stroke risk. The left atrial appendage (LAA) is the site of the highest clots formation, increasing the incidence of stroke in AF population. For many years oral anticoagulation therapy has been the most used AF treatment option available to decrease stroke risk. Unfortunately, several contraindications including bleeding risk increase, interference with other drugs and with multiorgan functioning, might outweigh its remarkable benefits on thromboembolic events. For these reasons, in recent years, other approaches have been designed, including LAA percutaneous closure. Unfortunately, nowadays, LAA occlusion (LAAO) is restricted to small subgroups of patients and require a certain level of expertise and training to successfully complete the procedure without complications. The most critical clinical problems associated with LAAO are represented by peri-device leaks and device related thrombus (DRT). The anatomical variability of the LAA plays a key role in the choice of the correct LAA occlusion device and in its correct positioning with respect to the LAA ostium during the implant. In this scenario, computational fluid dynamics (CFD) simulations could have a crucial role in improving LAAO intervention. The aim of this study was to simulate the fluid dynamics effects of LAAO in AF patients to predict hemodynamic changes due to the occlusion. LAAO was simulated by applying two different types of closure devices based on the plug and the pacifier principles on 3D LA anatomical models derived from real clinical data in five AF patients. CFD simulations were performed on the left atrium model before and after the LAAO intervention with each device. Blood velocity, particle washout and endothelial damage were computed to quantify flow pattern changes after the occlusion in relation to the thrombogenic risk. Our preliminary results confirmed an improved blood washout after the simulated implants and the capability of foreseeing thrombogenic risk based on endothelial damage and maximum blood velocities in different scenarios. This tool may help to identify effective device configurations in limiting stroke risk for patient-specific LA morphologies.

Comparison of different quantitative evaluation protocols for peri-device leak detection using cardiac computed tomography angiography after left atrial appendage closure

This study seeks to propose and compare different quantitative evaluation methods for identifying patients with peri-device leak (PDL) using cardiac computed tomography angiography (CCTA). Patients who had undergone left atrial appendage (LAA) closure and both transesophageal echocardiography (TEE) and CCTA were enrolled. Hounsfield units (HU) were measured in the proximal and distal regions of the left atrial appendage (p-LAA, d-LAA) on the CCTA, and the average of the two was determined (a-LAA). The relative HU ratios of the LAA to the center of the left atrium (LA) were calculated (p-LAA/c-LA, d-LAA/c-LA, a-LAA/c-LA). The area under the curve (AUC) for the LAA HU and the LAA/LA HU ratio were analyzed and compared. Fifty-one patients were included in this study. Pairwise comparisons showed a statistically significant difference (p = 0.029) in diagnostic performance between the d-LAA (AUC = 0.868) and a-LAA (AUC = 0.972). There were no significant differences between the a-LAA and p-LAA (p = 0.549) or between the d-LAA and p-LAA (p = 0.053). At the optimal cutoff for a-LAA of 115.5 HU, the sensitivity was 100%, the specificity was 88%. At the optimal cutoff for p-LAA of 109 HU, the sensitivity was 100%, the specificity was 84%. The LAA/LA HU ratio did not exhibit better diagnostic performance than HU attenuation in the LAA (p > 0.05). The a-LAA > 115.5 is useful in identifying PDL. Due to its convenience and intuitiveness, p-LAA > 109.0 can also be used as an alternative protocol for a-LAA.

Impact and predictors of device-related thrombus after percutaneous left atrial appendage closure

Device-related thrombus (DRT) is a known complication occurring in up to 7% of patients undergoing percutaneous left atrial appendage closure (LAAC). Since the target population of LAAC is generally ineligible for oral anticoagulant therapies, DRT raises important concerns. The aim of this review will be to summarize available evidence on DRT after LAAC focusing on its possible impact on outcomes. Recent findings showed a tighter association between DRT and neurological ischemic events. Antithrombotic regimen adopted after LAAC may have a protective effect against DRT. Many patient-related and procedural factors have been identified as possible predictors of DRT. A tailored approach, which takes into account DRT, is needed in the patient selection for LAAC and in the postprocedural follow-up.

An updated meta-analysis of device related thrombus following left atrial appendage closure in patients with atrial fibrillation

Aims

Device related thrombus (DRT) is a known complication of left atrial appendage closure (LAAC). However, the relation between DRT and elevated risk of ischemic events remains controversial. This study is sought to reassessed the incidence of DRT following LAAC and the relation between DRT and elevated risk of ischemic stroke and systemic embolism (SE) with latest clinical trials included.

Methods

The PubMed, Embase, and Cochrane Library databases were systematically searched from their inception until April 2022 for studies that reported the incidence of DRT and compared the incidence of both stroke and SE between DRT patients and non-DRT patients.

Results

In 59 eligible studies, the incidence of DRT was 366/12,845 (2.8%, ranging from 0 to 11%, I ² = 64%). The incidence of DRT was not statistically different between single-seal device (SS) and dual-seal device (DS) in subgroup analysis [171/6,190 (2.8%) vs. 78/3,023 (3.6%); p = 0.93]. The pooled incidence of stroke (26 studies, 7,827 patients) in patients with and without DRT was 11.5% in DRT patients and 2.9% among non-DRT patients (OR: 5.08; 95% CI = 3.47-7.44). In the sensitivity analysis, DRT was associated with higher rate of stroke (12.1 vs. 3.2%; OR: 4.14; 95% CI = 2.69-6.38) and SE (16.0 vs. 3.8%; OR: 4.48; 95% CI = 3.04-6.62).

Conclusion

The incidence of DRT was low and similar between SS and DS devices. DRT was associated with increased rates of ischemic events. The occurrence rate of ischemic events associated DRT was comparable between two occlusion mechanism devices.

Systematic review registration

[https://www.crd.york.ac.uk/], identifier [CRD42022326179].

Cardiac computed tomography following Watchman FLX implantation: device-related thrombus or device healing?

AIMS

Cardiac computed tomography (CT) is increasingly utilized during follow-up after left atrial appendage closure (LAAC). Hypoattenuated thickening (HAT) is a common finding and might represent either benign device healing or device-related thrombosis (DRT). The appearance and characteristics of HAT associated with the Watchman FLX have not been previously described. Therefore, we sought to investigate cardiac CT findings during follow-up after Watchman FLX implantation with a focus on HAT and DRT.

METHODS AND RESULTS

Retrospective single-centre, observational study including all patients with successful Watchman FLX implantation and follow-up cardiac CT between March 2019 and September 2021 (n = 244). Blinded analysis of CT images was performed describing the localization, extent, and morphology of HAT and correlated to imaging and histology findings in a canine model. Relevant clinical and preclinical ethical approvals were obtained.Overall, HAT was present in 156 cases (64%) and could be classified as either subfabric hypoattenuation (n = 59), flat sessile HAT (n = 78), protruding sessile HAT (n = 16), or pedunculated HAT (n = 3). All cases of pedunculated HAT and five cases of protruding sessile HAT were considered as high-grade HAT (n = 7). Subfabric hypoattenuation and flat sessile HAT correlated with device healing and endothelialization in histological analysis of explanted devices.

CONCLUSION

Subfabric hypoattenuation and flat sessile HAT are frequent CT findings for Watchman FLX, likely representing benign device healing and endothelialization. Pedunculated HAT and protruding HAT are infrequent CT findings that might represent DRT.

Percutaneous Treatment Approaches in Atrial Fibrillation: Current Landscape and Future Perspectives

Atrial fibrillation (AF), the most common sustained arrhythmia in clinical practice, represents a major cause of morbidity and mortality, with an increasing prevalence. Pharmacologic treatment remains the cornerstone of its management through rhythm and rate control, as well as the prevention of thromboembolism with the use of oral anticoagulants. Recent progress in percutaneous interventional approaches have provided additional options in the therapeutic arsenal, however. The use of the different catheter ablation techniques can now lead to long arrhythmia-free intervals and significantly lower AF burden, thus reducing the rate of its complications. Particularly encouraging evidence is now available for patients with persistent AF or concomitant heart failure, situations in which catheter ablation could even be a first-line option. In the field of stroke prevention, targeting the left atrial appendage with percutaneous device implantation may reduce the risk of thromboembolism to lower rates than that predicted with conventional ischemic risk scores. Left atrial appendage occlusion through the approved Watchman or Amplatzer devices is a well-established, efficacious, and safe method, especially in high-ischemic and bleeding risk patients with contraindications for oral anticoagulation.

Bailout left atrial appendage occluder for pulmonary vein isolation and electrical cardioversion in patients with atrial fibrillation and left atrial appendage thrombus: a pilot study

BACKGROUND

Cardioversion and catheter-based circumferential pulmonary vein isolation (CPVI) are established rhythm control treatment strategies for patients with atrial fibrillation (AF). However, these treatments are contraindicated for AF patients with a left atrial appendage (LAA) thrombus.

METHODS

We conducted the first-in-man case series study to evaluate the feasibility and safety of performing cardioversion or CPVI in AF patients with LAA thrombus immediately after implantation of LAA Occluder (LAAO) in a combined procedure. In our multi-center LAAO registry of 310 patients, 27 symptomatic and drug-refractory AF patients underwent a combined procedure of LAAO and CPVI, among whom 10 (mean age 68 ± 16 years, 6 men) having anticoagulant-resistant LAA thrombus received a bailout procedure of LAAO implantation first then CPVI, and the other 17 patients without LAA thrombus received CPVI first then LAAO for comparison.

RESULTS

The mean CHA₂DS₂-VASc score and HAS-BLED score were comparable between these two groups. In patients with LAA thrombus, we put carotid filters and did a no-touch technique, neither advancing the wire and sheath into the LAA nor performing LAA angiography. After LAAO implantation, the connecting cable was still connected to the occluder when cardioversion was performed. During CPVI, the occluder location was registered in the LA geometry by three-dimensional mapping to guide the catheter not to touch the LAAO. The procedure was successful in all the patients without intra-procedural complications. After a mean follow-up of 1.7 ± 0.7 years, there was no device embolization, peri-device leak ≧ 5 mm or stroke event in both groups. The AF recurrence rate was also similar between the two groups (P = 0.697).

CONCLUSION

We demonstrated that cardioversion or CPVI is doable in symptomatic AF patients with LAA thrombus if LAA was occluded ahead as a bailout procedure.

Predictive Power for Thrombus Detection after Atrial Appendage Closure: Machine Learning vs. Classical Methods

Device-related thrombus (DRT) after left atrial appendage (LAA) closure is infrequent but correlates with an increased risk of thromboembolism. Therefore, the search for DRT predictors is a topic of interest. In the literature, multivariable methods have been used achieving non-consistent results, and to the best of our knowledge, machine learning techniques have not been used yet for thrombus detection after LAA occlusion. Our aim is to compare both methodologies with respect to predictive power and the search for predictors of DRT. To this end, a multicenter study including 1150 patients who underwent LAA closure was analyzed. Two lines of experiments were performed: with and without resampling. Multivariate and machine learning methodologies were applied to both lines. Predictive power and the extracted predictors for all experiments were gathered. ROC curves of 0.5446 and 0.7974 were obtained for multivariate analysis and machine learning without resampling, respectively. However, the resampling experiment showed no significant difference between them (0.52 vs. 0.53 ROC AUC). A difference between the predictors selected was observed, with the multivariable methodology being more stable. These results question the validity of predictors reported in previous studies and demonstrate their disparity. Furthermore, none of the techniques analyzed is superior to the other for these data.

Clinical and echocardiographic risk factors for device-related thrombus after left atrial appendage closure: an analysis from the multicenter EUROC-DRT registry

BACKGROUND

Data on Device-related Thrombus (DRT) after left atrial appendage closure (LAAC) remain scarce. This study aimed to investigate risk factors for DRT from centers reporting to the EUROC-DRT registry.

METHODS

We included 537 patients (112 with DRT and 425 without DRT) who had undergone LAAC between 12/2008 and 04/2019. Baseline and implantation characteristics, anti-thrombotic treatment and clinical outcomes were compared between both groups in uni- and multivariate analyses. Additional propensity-score matching (PSM) was conducted to focus on the role of implantation characteristics.

RESULTS

Patients with DRT showed higher rates of previous stroke/transient ischemic attack (TIA) (49.1% vs. 34.7%, p < 0.01), spontaneous echocardiographic contrast (SEC) (44.9% vs. 27.7%, p < 0.01) and lower left atrial appendage (LAA) peak emptying velocity (35.4 ± 18.5 vs. 42.4 ± 18.0 cm/s, p = 0.02). Occluders implanted in DRT patients were larger (25.5 ± 3.8 vs. 24.6 ± 3.5 mm, p = 0.03) and implanted deeper in the LAA (mean depth: 7.6 ± 4.7 vs. 5.7 ± 4.7 mm, p < 0.01). Coverage of the appendage ostium was achieved less often in DRT patients (69.5% vs. 81.5%, p < 0.01), while DRT patients were less frequently on oral anticoagulation (7.1% vs. 16.7%, p < 0.01). Multivariate analysis identified age, prior stroke/TIA and SEC as independent risk factors for DRT. After PSM, implantation depth was found to be predictive. Rates of stroke/TIA were higher in DRT patients (13.5% vs. 3.8%, Hazard Ratio: 4.21 [95%-confidence interval: 1.88-9.49], p < 0.01).

CONCLUSIONS

DRT after LAAC is associated with adverse outcome and appears to be of multifactorial origin, depending on patient characteristics, anticoagulation regimen and device position.

Device-related thrombus following left atrial appendage occlusion

Thrombus formation on intracardiac devices remains a subject of importance, with rates in the 2-5% range. Device-related thrombus (DRT) following left atrial appendage occlusion is an area of particular concern considering its association with embolic events. DRT continues to present numerous questions, including the optimal definition, incidence, risk factors, monitoring, therapy, and clinical outcomes - all subjects of ongoing assessment. Herein, we discuss these considerations, building upon the relevant historical context and pathophysiologic insights while discussing the future considerations in this rapidly evolving field.

The Future of LAAC-In 5, 10, and 20 Years

Early experience with percutaneous LAA closure documented complication rates of ∼10%, with failure to implant devices in ∼10% of patients. These numbers are unrecognizable in contemporary practice due to the iterative changes made largely in the last 10 years. Here we look forward to ask what might change, and when, to bring percutaneous LAA closure out of the niche early adopter centers into routine use. We consider the opportunity to incorporate different technologies into LAAc devices in the context of managing patient with atrial fibrillation. Finally, we consider how to make the procedure safer and more effective.

The Strengths and Weaknesses of the LAA Covering Disc Occluders-Conceptually and in Practice

Endocardial left atrial appendage (LAA) occluders with a covering disc encompass a wide range of devices that share the common feature of a distal anchoring "body" and proximal covering "disc" design. This unique design feature has potential advantages in certain complex LAA anatomies and challenging clinical scenarios. The current review article summarizes the different features of established and novel devices, preprocedural imaging updates, intraprocedural technical considerations, and postprocedural follow-up issues specific to this category of LAA occluders.

Watchman FLX vs. Watchman 2.5 in a Dual-Center Left Atrial Appendage Closure Cohort: the WATCH-DUAL study

AIMS

No studies have compared Watchman 2.5 (W2.5) with Watchman FLX (FLX) devices to date. We aimed at comparing the FLX with W2.5 devices with respect to clinical outcomes, left atrial appendage (LAA) sealing properties and device-related thrombus (DRT).

METHODS AND RESULTS

All consecutive left atrial appendage closure (LAAC) procedures performed at two European centres between November 2017 and February 2021 were included. Procedure-related complications and net adverse cardiovascular events (NACE) at 6 months after LAAC were recorded. At 45-day computed tomography (CT) follow-up, intra- (IDL) and peri- (PDL) device leak, residual patent neck area (RPNA), and DRT were assessed by a Corelab. Out of 144 LAAC consecutive procedures, 71 and 73 interventions were performed using W2.5 and FLX devices, respectively. There were no differences in terms of procedure-related complications (4.2% vs. 2.7%, P = 0.626). At 45-day CT, the FLX was associated with lower frequency of IDL [21.3% vs. 40.0%; P = 0.032; odds ratio (OR): 0.375; 95% confidence interval (CI): 0.160-0.876; P = 0.024], similar rate of PDL (29.5% vs. 42.0%; P = 0.170), and smaller RPNA [6 (0-36) vs. 40 (6-115) mm2; P = 0.001; OR: 0.240; 95% CI: 0.100-0.577; P = 0.001] compared with the W2.5 group. At 45 days, rate of DRT as detected by CT and/or transoesophageal echocardiography (TOE), was higher with W2.5 (6.0% vs. 0%, P = 0.045). At 6-month follow-up, NACE did not differ between groups.

CONCLUSIONS

In this cohort of consecutive LAACs, FLX as compared to W2.5, was associated with similar procedure-related complications and 6-month NACE, but with improved LAA neck coverage, and lower IDL and DRT.

Residual stroke risk after left atrial appendage closure in patients with prior oral anticoagulation failure

BACKGROUND

Patients with atrial fibrillation (AF) and oral anticoagulation (OAC) failure may benefit from left atrial appendage closure (LAAC), however, the evidence is scarce. We report outcomes of LAAC in patients with OAC failure compared to those with classic indications of OAC contraindications.

METHODS

Prospective registry of LAAC with Amplatzer or WATCHMAN device followed by dual antiplatelet therapy (DAPT) was analyzed (05.2014-11.2019). The study group included patients with OAC failure defined as stroke/TIA/PE/LAA thrombus (n = 39) during OAC, whereas the control group consisted of patients with OAC contraindications (n = 156). Structured follow-up at 3, 6, and 12 months was done.

RESULTS

The study group compared to controls was younger [73 (IQR, 62-77) vs 74 (IQR, 68-81) years, P = 0.046], with higher CHA₂DS₂-VASc [5.0 (IQR, 3.0-6.0) vs 4.0 (IQR, 3.0-5.0), P = 0.001)], lower HAS-BLED [2.0 (IQR, 1.0-3.0) vs 3.0 (IQR, 2.0-3.0), P = 0.006] and similar proportion of WATCHMAN implantations (43.6% vs 44.2%, P = 1.000). The reduction from CHA₂DS₂-VASc predicted to observed annual stroke/TIA/PE rate was markedly smaller in the study vs control group (14% vs 77%) with 10.3% vs 1.9% stroke/TIA/PE respectively (P = 0.031). The reduction from HAS-BLED predicted to observed annual major nonprocedural bleeding rate was higher (100% vs 7.4%) with 0.0% vs 5.1% major bleedings respectively (P = 0.361). The device-related thrombosis remained similar (13.2% vs 11.3%, P = 0.778).

CONCLUSIONS

Patients after LAAC for OAC failure and unremarkable prior bleeding history presented with high residual stroke and low bleeding risks. Therefore concomitant long-term OAC or prolonged DAPT should strongly be considered in this population.

Percutaneous extraction of a large device-related thrombus on a Watchman™ device: a case report

Background

Left atrial appendage occlusion devices are commonly used to prevent stroke in patients with persistent atrial fibrillation who are unable to tolerate anticoagulation. However, certain patient- and device-related characteristics increase the risk for the development of a device-related thrombus (DRT). The presence of a DRT increases the risk of stroke and should be treated. Management of DRT lacks consensus but is mostly focused on anticoagulation. In patients with large thrombi that need to be managed urgently, percutaneous extraction may be a viable option.

Case summary

In this report, we describe the successful management of a DRT via percutaneous thrombus extraction technology in an 81-year-old woman with a large thrombus attached to a WATCHMAN™ device. The patient initially presented with shortness of breath, and on imaging a pedunculated thrombus was detected. The thrombus was extracted using a Penumbra Lightning 12™ (Penumbra Inc., Alameda, CA, USA) catheter with a Sentinel™ (Boston Scientific, Marlborough, MA, USA) cerebral embolic protection device. The patient had no neurologic sequelae and was started on anticoagulation.

Discussion

Percutaneous thrombectomy can be safely performed to extract large left atrial occlusion DRT that require urgent management, without any neurologic sequelae. We believe this can be used in patients with a large DRT who would not be adequately managed with anticoagulation and in whom surgery is not feasible.

Prevalence, mechanisms and impact of residual patency and device-related thrombosis following left atrial appendage occlusion: a computed tomography analysis

BACKGROUND

Cardiac computed tomography angiography (CCTA) appears to be an appropriate imaging technique for device surveillance after left atrial appendage occlusion (LAAO). However, the available experience is limited.

AIMS

The aim of this study was to determine the prevalence, mechanisms and clinical impact of left atrial appendage (LAA) patency and device-related thrombosis (DRT) following LAAO utilising a novel CCTA-based classification.

METHODS

Consecutively enrolled patients who underwent LAAO with an AMPLATZER device were followed up with CCTA. Mechanisms and frequency of residual patency were evaluated and correlated with clinical events. Atrial-side device thrombus, device positioning and presence of signs of device stability were also analysed.

RESULTS

A total of 137 patients were included. LAA patency was observed in 56.9% (n=78). Mechanisms and frequency of patency were: malapposition of proximal segment of the device lobe (55.1%), peri-device leak (PDL, 34.6%) and fabric permeability (5.8%). Lobe-LAA axis misalignment was the only independent predictor of device patency after LAAO (HR 38.3, 95% CI: 13.6-107.0; p<0.001). After a median follow-up of 638 days, patency was not associated with an increased risk of death (all-cause or cardiovascular death) or cerebral/peripheral embolism regardless of its mechanism. Any degree of hypo-attenuated thickening (HAT) was found in 16.8% (n=23) of patients, of whom 16 (11.7%) had low-grade HAT and 7 (5.1%) had high-grade HAT or definite DRT. Complete sealing was associated with increased rates of low-grade HAT.

CONCLUSIONS

LAA patency on CCTA follow-up is a frequent phenomenon due to malapposition of the proximal segment of the device lobe, PDL or fabric permeability. Patency was not associated with adverse outcomes. Low-grade HAT may be related to a benign, uneventful, endothelialisation process favoured by complete LAAO.

Amulet or Watchman Device for Percutaneous Left Atrial Appendage Closure: Primary Results of the SWISS-APERO Randomized Clinical Trial

Background: No study has so far compared Amulet with the new Watchman FLX in terms of residual left atrial appendage (LAA) patency or clinical outcomes in patients undergoing percutaneous LAA closure (LAAC). Methods: In the investigator-initiated SWISS APERO trial, patients undergoing LAAC were randomized (1:1) open-label to receive Amulet or Watchman 2.5 or FLX (Watchman) across 8 European centres. The primary endpoint was the composite of justified crossover to a non-randomized device during LAAC procedure or residual LAA patency detected by cardiac computed tomography angiography (CCTA) at 45 days. The secondary endpoints included procedural complications, device related thrombus (DRT), peridevice leak (PDL) at transesophageal echocardiography (TEE) and clinical outcomes at 45 days. Results: Between June 2018, and May 2021, 221 patients were randomly assigned to Amulet (111 [50.2%]) or Watchman (110 [49.8%]), of whom 25 (22.7%) patients included before October 2019 received Watchman 2.5, and 85 (77.3%) patients received Watchman FLX. The primary endpoint was assessable in 205 (92.8%) patients and occurred in 71 (67.6%) Amulet and 70 (70.0%) Watchman patients respectively (risk ratio [RR] 0.97 [95% CI 0.80- 1.16]; P=0.713). A single justified cross-over occurred in an Amulet patient who fulfilled LAA patency criteria at 45-day CCTA. Major procedure related complications occurred more frequently in the Amulet group (9.0% vs. 2.7%; P=0.047), owing to more frequent bleeding (7.2% vs.1.8%). At 45 days, the PDL rate at TEE was higher with Watchman than Amulet (27.5% vs. 13.7%, p=0.020), albeit none was major (i.e. > 5 mm), whereas DRT was detected in 1 (0.9%) patient with Amulet and 3 (3.0%) patients with Watchman at CCTA and in 2 (2.1%) and 5 (5.5%) patients at TEE, respectively. Clinical outcomes at 45 days did not differ between the groups. Conclusions: Amulet was not associated with lower rate of the composite of crossover or residual LAA patency compared with Watchman at 45-day CCTA. Amulet, was however associated with lower PDL rates at TEE, higher procedural complications and similar clinical outcomes at 45 days compared with Watchman. The clinical relevance of CCTA-detected LAA patency requires further investigation. Clinical Trial Registration: URL https://clinicaltrials.gov Unique Identifier NCT03399851.

Incidence and clinical impact of major bleeding following left atrial appendage occlusion: insights from the Amplatzer Amulet Observational Post-Market Study

BACKGROUND

Major bleeding (MB) events are independent predictors of mortality after cardiac interventional procedures. The clinical relevance of MB following left atrial appendage occlusion (LAAO) remains unclear.

AIMS

This study aimed to investigate the incidence and clinical impact of MB after LAAO in a real-world population at high risk for bleeding and contraindicated to anticoagulation.

METHODS

The two-year results of the Amplatzer Amulet Observational Post-Market Study were analysed. An independent committee adjudicated MBs according to the Bleeding Academic Research Consortium scale. Cox proportional hazards regression identified variables associated with MB events and mortality.

RESULTS

The MB rate was 7.2%/year, with a rate of 10.1%/year during year one, decreasing to 4.0%/year over year two. The most common bleeding location was gastrointestinal, accounting for 48% of MBs. Pre-LAAO MB was associated with an increased risk for post-LAAO MB (HR 2.34, 95% CI: 1.37-3.99). The occurrence of post-LAAO MB was associated with increased mortality (37.3% vs 12.7%; p<0.0001), driven mainly by events occurring beyond the periprocedural period. The annualised rate of ischaemic stroke or TIA was similar in patients with and without MB (2.3% vs 3.3%; p=0.446). MB post LAAO was a strong independent predictor of mortality (HR 3.07, 95% CI: 2.15-4.40).

CONCLUSIONS

In real-world patients at high bleeding risk, MB following LAAO was not uncommon and associated with a significant increase in mortality, without increasing the risk of stroke. ClinicalTrials.gov Identifier: NCT02447081. https://clinicaltrials.gov/ct2/show/NCT02447081.

Sensitivity Analysis of In Silico Fluid Simulations to Predict Thrombus Formation after Left Atrial Appendage Occlusion

Atrial fibrillation (AF) is nowadays the most common human arrhythmia and it is considered a marker of an increased risk of embolic stroke. It is known that 99% of AF-related thrombi are generated in the left atrial appendage (LAA), an anatomical structure located within the left atrium (LA). Left atrial appendage occlusion (LAAO) has become a good alternative for nonvalvular AF patients with contraindications to anticoagulants. However, there is a non-negligible number of device-related thrombus (DRT) events, created next to the device surface. In silico fluid simulations can be a powerful tool to better understand the relation between LA anatomy, haemodynamics, and the process of thrombus formation. Despite the increasing literature in LA fluid modelling, a consensus has not been reached yet in the community on the optimal modelling choices and boundary conditions for generating realistic simulations. In this line, we have performed a sensitivity analysis of several boundary conditions scenarios, varying inlet/outlet and LA wall movement configurations, using patient-specific imaging data of six LAAO patients (three of them with DRT at follow-up). Mesh and cardiac cycle convergence were also analysed. The boundary conditions scenario that better predicted DRT cases had echocardiography-based velocities at the mitral valve outlet, a generic pressure wave from an AF patient at the pulmonary vein inlets, and a dynamic mesh approach for LA wall deformation, emphasizing the need for patient-specific data for realistic simulations. The obtained promising results need to be further validated with larger cohorts, ideally with ground truth data, but they already offer unique insights on thrombogenic risk in the left atria.

Analysis of outcome of 6-month readmissions after percutaneous left atrial appendage occlusion

OBJECTIVE

Percutaneous left atrial appendage occlusion (LAAO) is an alternative strategy for prevention of thromboembolic events in patients with atrial fibrillation and unsuitable for long-term oral anticoagulation. The study aimed to evaluate the causes and timing of readmissions within 6 months following percutaneous LAAO in a real-world setting.

METHODS

We conducted a retrospective cohort study of percutaneous LAAO performed in the USA between January and June of 2016-2018 using the Nationwide Readmissions Database.

RESULTS

Overall, 12 446 patients who underwent LAAO were included in the analyses and 3477 patients (28%) were readmitted within 6 months following the interventions. Readmitted patients were more often women (p=0.001). The index hospitalisation was characterised by longer duration of hospital stay (p<0.001) and complicated with acute kidney injury (p<0.001) among readmitted patients compared with those without readmissions. Readmissions within 6 months following the index intervention were mainly due to heart failure (13%) and gastrointestinal bleeding (12%). Characteristics associated with readmissions due to heart failure included previously known heart failure (HR 2.39; 95% CI 1.70 to 3.37), valvular heart disease (HR 1.39; 95% CI 1.05 to 1.84) and chronic kidney disease (HR 1.42; 95% CI 1.03 to 1.94). Readmissions due to gastrointestinal bleeding were associated with diabetes mellitus (HR 1.78; 95% CI 1.25 to 2.53), chronic kidney disease (HR 1.86; 95% CI 1.23 to 2.81) and previous anaemia (HR 2.41; 95% CI 1.54 to 3.77).

CONCLUSIONS

After percutaneous LAAO, over a quarter of the patients in the USA required rehospitalisation within 6 months, mainly due to heart failure and gastrointestinal bleeding.

The use of cardiac computed tomography angiography in the assessment of percutaneous left atrial appendage closure - Review and experts recommendations endorsed by the Société française d'imagerie cardiaque et vasculaire diagnostique et interventionnelle

Atrial fibrillation is the most common cause of arrhythmia which is responsible for over 15% of ischemic strokes, most of these being secondary to migration of a left atrial appendage (LAA) thrombus. In patient with contraindication to anticoagulant therapy, percutaneous closure system placement may be indicated. Cardiac computed tomography (CT) angiography plays a central role in the initial assessment as well as in the follow-up. The purpose of the pre-implantation cardiac CT angiography is to evaluate the anatomy of the LAA in order to select the most suitable prosthesis and check for any contraindication to device implantation. Image analysis is divided into four steps that include analysis of the approach; search for a thrombus in the LAA; investigation of the anatomy of the LAA (morphology of the LAA, dimensions of the LAA and choice of device) and cardiac and thoracic assessments. Follow-up involves CT examination to check for correct placement of the device and to detect any complications. On the basis of the results of currently available published research, a panel of experts has issued recommendations regarding cardiac CT angiography prior to percutaneous LAA closure device placement, which were further endorsed by the Société française d'imagerie cardiaque et vasculaire diagnostique et interventionnelle (SFICV).

Impact of atrial fibrillation pattern on outcomes after left atrial appendage closure: lessons from the prospective LAARGE registry

BACKGROUND

Non-paroxysmal (NPAF) forms of atrial fibrillation (AF) have been reported to be associated with an increased risk for systemic embolism or death.

METHODS

Comparison of procedural details and long-term outcomes in patients (pts) with paroxysmal AF (PAF) against controls with NPAF in the prospective, multicentre observational registry of patients undergoing LAAC (LAARGE).

RESULTS

A total of 638 pts (PAF 274 pts, NPAF 364 pts) were enrolled. In both groups, a history of PVI was rare (4.0% vs 1.6%, p = 0.066). The total CHA₂DS₂-VASc score was lower in the PAF group (4.4 ± 1.5 vs 4.6 ± 1.5, p = 0.033), while HAS-BLED score (3.8 ± 1.1 vs 3.9 ± 1.1, p = 0.40) was comparable. The rate of successful implantation was equally high (97.4% vs 97.8%, p = 0.77). In the three-month echo follow-up, LA thrombi (2.1% vs 7.3%, p = 0.12) and peridevice leak > 5 mm (0.0% vs 7.1%, p = 0.53) were numerically higher in the NPAF group. Overall, in-hospital complications occurred in 15.0% of the PAF cohort and 10.7% of the NPAF cohort (p = 0.12). In the one-year follow-up, unadjusted mortality (8.4% vs 14.0%, p = 0.039) and combined outcome of death, stroke and systemic embolism (8.8% vs 15.1%, p = 0.022) were significantly higher in the NPAF cohort. After adjusting for CHA₂DS₂-VASc and previous bleeding, NPAF was associated with increased death/stroke/systemic embolism (HR 1.67, 95% CI 1.02-2.72, p = 0.041).

CONCLUSION

Atrial fibrillation type did not impair periprocedural safety or in-hospital MACE patients undergoing LAAC. However, after one year, NPAF was associated with higher mortality.

Device-Related Thrombus After Left Atrial Appendage Closure: Data on Thrombus Characteristics, Treatment Strategies, and Clinical Outcomes From the EUROC-DRT-Registry

[Figure: see text].

Left atrial appendage occlusion with the Amplatzer™ Amulet™ device: full results of the prospective global observational study

AIMS

To evaluate the safety and efficacy of left atrial appendage occlusion (LAAO) with the Amplatzer™ Amulet™ occluder.

METHODS AND RESULTS

Patients with atrial fibrillation eligible for LAAO were recruited to a prospective global study. Implant procedures were undertaken with echocardiographic guidance. Transoesophageal echocardiography (TOE) was undertaken 1-3 months post-LAAO. Implant and follow-up TOEs were evaluated by a CoreLab. The primary endpoint was a composite of ischaemic stroke and cardiovascular death at 2 years. Serious adverse events were adjudicated by an independent clinical events committee. A total of 1088 patients were enrolled, aged 75.2 ± 8.5 years; 64.5% were male. CHA2DS2-VASc and HAS-BLED scores were 4.2 ± 1.6 and 3.3 ± 1.1, respectively. A total of 71.7% had prior major bleeding, and 82.8% had contraindications to oral anticoagulants. Implant success was 99.1%. Major adverse events (≤7 days post-procedure) occurred in 4.0%, including death (0.3%), stroke (0.4%), major vascular (1.3%), and device embolization (0.2%). A total of 80.2% of patients were discharged on antiplatelet therapy alone. Peridevice flow was <3 mm in 98.4% at follow-up TOE. Device-related thrombus (DRT) was seen in 1.6% of cases. Cardiovascular death or ischaemic stroke occurred in 8.7% of patients at 2 years. The ischaemic stroke rate was 2.2%/year-a 67% reduction compared to the CHA2DS2-VASc predicted rate. Major bleeding (Bleeding Academic Research Consortium type ≥ 3) occurred at rates of 10.1%/year (year 1) and 4.0%/year (year 2).

CONCLUSION

Following LAAO with the Amplatzer Amulet device, the ischaemic stroke rate was reduced by 67% compared to the predicted risk. Closure was complete in 98.4% of cases and DRT seen in only 1.6%.