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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., (© 2023. The Author(s).)

Cardiac compartmental size depends on sex, with smaller values found in (healthy) women compared to a matched group of men. Various types of heart disease may cause dilation of the affected chamber. For example, atrial fibrillation (AF) is associated with enlarged left atrial (LA) size, often also implying increased left ventricular (LV) size. Sex-specific differences appear to persist during disease states. Thus, chamber volumes depend on both sex and the severity of the underlying disorder, and require quantification to evaluate the effect of interventions. Often, we rely on the popular performance metric ejection fraction (EF) which refers to the ratio of the minimum and maximum LV or LA volumetric values observed during the cardiac cycle. Here we discuss a sex stratified analysis of LVEF and LAEF in AF patients as treated by LA appendage closure, while comparing those with or without device-related thrombosis. Also, an alternative analysis based on primary data is presented while emphasizing its attractiveness. In any event, age- and sex-specific reference values as broadly documented for various imaging modalities should be applied to LA and LV., (© 2024 Wiley Periodicals LLC.)

Background: Device-related thrombosis (DRT) is a common finding after left atrial appendage closure (LAAC) and is associated with worse outcomes. As women are underrepresented in clinical studies, further understanding of sex differences in DRT patients is warranted., Methods and Results: This sub-analysis from the EUROC-DRT-registry compromises 176 patients with diagnosis of DRT after LAAC. Women, who accounted for 34.7% (61/176) of patients, were older (78.0 ± 6.7 vs. 74.9 ± 9.1 years, p = .06) with lower rates of comorbidities. While DRT was detected significantly later in women (173 ± 267 vs. 127 ± 192 days, p = .01), anticoagulation therapy was escalated similarly, mainly with initiation of novel oral anticoagulant (NOAC), vitamin K antagonist (VKA) or heparin. DRT resolution was achieved in 67.5% (27/40) of women and in 75.0% (54/72) of men (p = .40). In the remaining cases, an intensification/switch of anticoagulation was conducted in 50.% (9/18) of men and in 41.7% (5/12) of women. Final resolution was achieved in 72.5% (29/40) cases in women, and in 81.9% (59/72) cases in men (p = .24). Women were followed-up for a similar time as men (779 ± 520 vs. 908 ± 687 days, p = .51). Kaplan-Meier analysis revealed no difference in mortality rates in women (Hazard Ratio [HR]: 1.73, 95%-Confidence interval [95%-CI]: .68-4.37, p = .25) and no differences in stroke (HR: .83, 95%-CI: .30-2.32, p = .72) within 2 years after LAAC., Conclusion: Evaluation of risk factors and outcome revealed no differences between men and women, with DRT in women being diagnosed significantly later. Women should be monitored closely to assess for DRT formation/resolution. Treatment strategies appear to be equally effective., (© 2024 The Author(s). Echocardiography published by Wiley Periodicals LLC.)

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.

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., (© 2023. The Author(s).)

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., Competing Interests: Funding Support and Author Disclosures Dr Alkhouli is on the advisory boards of Boston Scientific, Abbott, and Philips. Dr Nielsen-Kudsk is on the advisory boards of Boston Scientific and Philips. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023. Published by Elsevier Inc.)

Background: Scarce data exist on the evolution of device-related thrombus (DRT) after left atrial appendage closure (LAAC)., Objectives: This study sought to assess the incidence, predictors, and clinical impact of persistent and recurrent DRT in LAAC recipients., Methods: Data were obtained from an international multicenter registry including 237 patients diagnosed with DRT after LAAC. Of these, 214 patients with a subsequent imaging examination after the initial diagnosis of DRT were included. Unfavorable evolution of DRT was defined as either persisting or recurrent DRT., Results: DRT resolved in 153 (71.5%) cases and persisted in 61 (28.5%) cases. Larger DRT size (OR per 1-mm increase: 1.08; 95% CI: 1.02-1.15; P = 0.009) and female (OR: 2.44; 95% CI: 1.12-5.26; P = 0.02) were independently associated with persistent DRT. After DRT resolution, 82 (53.6%) of 153 patients had repeated device imaging, with 14 (17.1%) cases diagnosed with recurrent DRT. Overall, 75 (35.0%) patients had unfavorable evolution of DRT, and the sole predictor was average thrombus size at initial diagnosis (OR per 1-mm increase: 1.09; 95% CI: 1.03-1.16; P = 0.003), with an optimal cutoff size of 7 mm (OR: 2.51; 95% CI: 1.39-4.52; P = 0.002). Unfavorable evolution of DRT was associated with a higher rate of thromboembolic events compared with resolved DRT (26.7% vs 15.1%; HR: 2.13; 95% CI: 1.15-3.94; P = 0.02)., Conclusions: About one-third of DRT events had an unfavorable evolution (either persisting or recurring), with a larger initial thrombus size (particularly >7 mm) portending an increased risk. Unfavorable evolution of DRT was associated with a 2-fold higher risk of thromboembolic events compared with resolved DRT., Competing Interests: Funding Support and Author Disclosures Dr Rodés-Cabau holds the Research Chair “Fondation Famille Jacques Larivière” for the Development of Structural Heart Disease Interventions (Laval University, Quebec City, Canada). He also has received institutional research grants from Boston Scientific. Dr Maarse has received an unrestricted grant from Boston Scientific. Dr Pérez de Prado has served as a proctor for Boston Scientific. Dr Gupta has served as a proctor for Abbott. Dr Sanchez has served as a speaker and proctor for Boston Scientific. Dr Wang has served as a consultant for Edwards Lifesciences, Boston Scientific, and Neochord; and received research grant support from Boston Scientific assigned to his employer, the Henry Ford Health System. Dr Demkow has served as a proctor for Abbott and Boston Scientific. Dr Alkhouli has served as a consultant for Boston Scientific. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

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., Competing Interests: Funding Support and Author Disclosures Dr De Backer has received institutional research grants and consulting fees from Abbott and Boston Scientific. Dr Sanchis is a proctor for Abbott Medical. Dr Garot has received speaker and advisory fees from Abbott, Biosensors, Boston Scientific, Edwards Lifesciences, GE Healthcare, and Terumo; and serves as medical director for and is a shareholder in the Cardiovascular European Research Center. Dr Aminian is a proctor and consultant for Abbott and Boston Scientific. Dr Rodés-Cabau has received an institutional research grant from Boston Scientific. Dr Freixa is a proctor for Abbott Medical. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

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)., Competing Interests: Funding Support and Author Disclosures Abbott funded the Amulet IDE trial. No funding was provided for this analysis. Dr Schmidt has received speaker honoraria and consulting fees from Abbott, Boston Scientific, Biosense Webster, and Medtronic. Dr Nielsen-Kudsk has received institutional research grants from Abbott and Boston Scientific. Dr Ellis has received institutional research grants from Boehringer Ingelheim, Medtronic, Boston Scientific. Consulting/Advisory- Medtronic, Abbott Medical, Boston Scientific, and Atricure. Dr Thaler has received consulting fees from Abbott and Occlutech; and institutional research grants for clinical trials from Abbott and the National Institutes of Health. Dr Sabir has received institutional research grants for clinical trials from Abbott and Boston Scientific; and speaker honoraria or consulting fees from Abbott and Boston Scientific. Dr Gambhir has received consulting fees from Abbott, Biosense Webster, and Boston Scientific; and speaker honoraria from Boston Scientific. Dr Landmesser has served as an advisor to and received fees from Abbott, Biotronik, Rewa, and Bayer. Dr Shah has no disclosures. Dr Gray has served as a consultant for or has received grant support from Boston Scientific, Cook Medical, Medtronic, Surmodics, and Philips. Dr Swarup has received consulting fees from Biosense Webster, Boston Scientific, and Abbott. Dr Lim’s institution has received research grant funding on his behalf from Abbott, Boston Scientific, Edwards Lifesciences, and Medtronic; and has also received consulting fees from Venus Medtech and W.L. Gore. Dr Koulogiannis has received speaker honoraria from Abbott and consulting fees from Edwards Lifesciences. Dr Anderson and Mr Gage are employees of Abbott. Dr Lakkireddy has received research and educational grants to his institution from Abbott, Atricure, Alta Thera, Medtronic, Biosense Webster, Biotronik, and Boston Scientific; and speaker honoraria from Abbott, Medtronic, Biotronik, and Boston Scientific., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

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., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

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., Competing Interests: Conflict of interest: S.W. reports research and educational grants to the institution from Abbott, Amgen, BMS, Bayer, Boston Scientific, Biotronik, Cardinal Health, CardioValve, CSL Behring, Daiichi Sankyo, Edwards Lifesciences, Johnson & Johnson, Medtronic, Querbet, Polares, Sanofi, Terumo, and Sinomed. He serves as unpaid advisory board member and/or unpaid member of the steering/executive group of trials funded by Abbott, Abiomed, Amgen, Astra Zeneca, BMS, Boston Scientific, Biotronik, Cardiovalve, Edwards Lifesciences, MedAlliance, Medtronic, Novartis, Polares, Sinomed, V-Wave, and Xeltis but has not received personal payments by pharmaceutical companies or device manufacturers. He is also member of the steering/executive committee group of several investigated-initiated trials that receive funding by industry without impact on his personal remuneration. He is an unpaid member of the Pfizer Research Award selection committee in Switzerland. M.V. has received grants and/or personal fees from AstraZeneca, Terumo, Alvimedica/CID, Abbott Vascular, Daiichi-Sankyo, Opsens, Bayer, CoreFLOW, Idorsia Pharmaceuticals Ltd., Universität Basel Department Klinische Forschung, Vifor, Bristol-Myers Squibb SA, iVascular, and Medscape. N.A. reports research grants from Abbott Vascular, consulting fees from Abbott Vascular and Boston Scientific and proctoring fees from Abbott Vascular and Boston Scientific. L.R. reports research grants to institution by Abbott Vascular, Boston Scientific, Biotronik, Heartflow, Infraredx, Sanofi, and Regeneron and speaker/consultation fees by Abbott Vascular, Amgen, AstraZeneca, CSL Behring, Canon, Occlutech, Sanofi, and Vifor. All remaining authors have declared no conflicts of interest., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2022. For permissions, please email: journals.permissions@oup.com.)

Competing Interests: Funding Support and Author Disclosures The authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Objectives: This study sought to report the incidence of device-related thrombosis (DRT) and thromboembolic (TE) events when an alternative to clopidogrel is prescribed in loss-of-function (LOF) allele carriers of the cytochrome P450 2C19 (CYP2C19) gene., Background: LOF polymorphisms of the CYP2C19 gene are associated with reduced hepatic bioactivation of clopidogrel., Methods: A total of 1,002 Watchman patients were included. Six hundred forty-five patients underwent CYP2C19 genetic testing; among patients with clopidogrel resistance, clopidogrel was replaced by either prasugrel (pilot cohort) or half dose direct oral anticoagulant ([DOAC]/Group 1), both in combination with aspirin. We compared the incidence of DRT/TE events among genotyped patients and a control group which received standard dual antiplatelet therapy (DAPT) (Group 2; n = 357). All reported events occurred during a timeframe between 45- and 180-day follow-up transesophageal echocardiograms, when the 2 different antithrombotic strategies (genotype-guided vs standard DAPT) were adopted., Results: In the pilot cohort (n = 244), bleeding events occurred in 10.2% of patients who received aspirin plus prasugrel, leading to early discontinuation of the prasugrel-based protocol. DOAC Group 1 patients (n = 401), 25.7% were reduced metabolizers, and clopidogrel was replaced by half dose direct oral anticoagulant. DRT was documented in 1 (0.2%) patient of Group 1 and 7 (1.96%) patients of Group 2 (log-rank P = 0.021). The composite endpoint of DRT/TE events was significantly lower among patients receiving a genotype-guided antithrombotic strategy (0.75% vs 3.10%; log-rank P = 0.017)., Conclusions: In Watchman patients, a genotype-based antithrombotic strategy with aspirin plus half dose DOAC in reduced clopidogrel metabolizers was superior to standard DAPT with respect to DRT/TE events., Competing Interests: Funding Support and Author Disclosures The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2021. Published by Elsevier Inc.)

Competing Interests: Funding Support and Author Disclosures The authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Background: Device-related thrombus (DRT) has been considered an Achilles' heel of left atrial appendage occlusion (LAAO). However, data on DRT prediction remain limited., Objectives: This study constructed a DRT registry via a multicenter collaboration aimed to assess outcomes and predictors of DRT., Methods: Thirty-seven international centers contributed LAAO cases with and without DRT (device-matched and temporally related to the DRT cases). This study described the management patterns and mid-term outcomes of DRT and assessed patient and procedural predictors of DRT., Results: A total of 711 patients (237 with and 474 without DRT) were included. Follow-up duration was similar in the DRT and no-DRT groups, median 1.8 years (interquartile range: 0.9-3.0 years) versus 1.6 years (interquartile range: 1.0-2.9 years), respectively (P = 0.76). DRTs were detected between days 0 to 45, 45 to 180, 180 to 365, and >365 in 24.9%, 38.8%, 16.0%, and 20.3% of patients. DRT presence was associated with a higher risk of the composite endpoint of death, ischemic stroke, or systemic embolization (HR: 2.37; 95% CI, 1.58-3.56; P < 0.001) driven by ischemic stroke (HR: 3.49; 95% CI: 1.35-9.00; P = 0.01). At last known follow-up, 25.3% of patients had DRT. Discharge medications after LAAO did not have an impact on DRT. Multivariable analysis identified 5 DRT risk factors: hypercoagulability disorder (odds ratio [OR]: 17.50; 95% CI: 3.39-90.45), pericardial effusion (OR: 13.45; 95% CI: 1.46-123.52), renal insufficiency (OR: 4.02; 95% CI: 1.22-13.25), implantation depth >10 mm from the pulmonary vein limbus (OR: 2.41; 95% CI: 1.57-3.69), and non-paroxysmal atrial fibrillation (OR: 1.90; 95% CI: 1.22-2.97). Following conversion to risk factor points, patients with ≥2 risk points for DRT had a 2.1-fold increased risk of DRT compared with those without any risk factors., Conclusions: DRT after LAAO is associated with ischemic events. Patient- and procedure-specific factors are associated with the risk of DRT and may aid in risk stratification of patients referred for LAAO., Competing Interests: Funding Support and Author Disclosures Dr Maarse has received an unrestricted grant from Boston Scientific. Dr Pérez de Prado has served as a proctor for Boston Scientific. Dr Gupta has served as a proctor for Abbott. Dr Sanchez has served as a speaker and proctor for Boston Scientific. Dr Demkow has served as a proctor for Abbott and Boston Scientific. Dr Alkhouli has served as a consultant for Boston Scientific. Dr Wang has been a consultant for Edwards LifeSciences, Boston Scientific, and Neochord; and has received research grant support from Boston Scientific assigned to employer Henry Ford health system. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2021 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: In this analysis of the EWOLUTION registry, we evaluated the incidence, relevance and predictors of device-related thrombus in a large multi-center real-world cohort undergoing LAAc with the WATCHMAN device., Methods and Results: We analyzed the 835 patients who underwent percutaneous LAA closure with the WATCHMAN device in the EWOLUTION registry in whom at least one TEE follow up was performed. Patients were 74 ± 9 y/o and were at high risk for stroke and bleeding (CHA2DS2-VASC-Score 4.3 ± 1.7; HAS-BLED-Score 2.3 ± 1.2). Device-related thrombus was detected in 4.1% (34/835) after a median of 54 days (IQR 42-111 days) with 91.2% (31/34) being detected within 3 months after the procedure or at the time of first TEE. Hereby DRT occurred irrespective of postprocedural anticoagulation. Patients with DRT more frequently had long-standing, non-paroxysmal atrial fibrillation (82.4 vs. 64.9%, p < .01), evidence of dense spontaneous echo contrast (26.5 vs. 11.9%, p = .03) and larger LAA diameters at the ostium (22.8 ± 3.5 vs. 21.1 ± 3.5 mm, p < .01) compared to patients without DRT. Left ventricular ejection fraction, device compression ratio and the incidence of renal dysfunction did not differ between the two groups. In a multivariate analysis, only non-paroxysmal atrial fibrillation identified as an independent predictor of developing DRT. Specific treatment of DRT was initiated in 62% (21/34) of patients whereas resolution was confirmed in 86% (18/21) of cases. Overall, no significant differences in annual rates of stroke/TIA or systemic embolism were observed in patients with or without DRT (DRT 1.7 vs. No-DRT 2.2%/year, p = .8)., Conclusions: In real-world patients undergoing LAAc with the WATCHMAN device, DRT is rare. DRT was most frequently detected within the first 3 months after LAAc regardless of post-procedural regimen and was not associated with an increased risk of stroke or SE. While long-standing atrial fibrillation was the only independent factor associated with DRT, medical treatment of DRT resulted in a resolution of thrombi in most cases., (© 2021 Wiley Periodicals LLC.)

Objectives: The aim of this study is to review the evidence on the use of antithrombotic therapy and risk of device-related thrombosis after left atrial appendage closure., Background: Left atrial appendage closure (LAAC) is increasingly performed for stroke prevention in patients with nonvalvular atrial fibrillation, especially those who cannot tolerate or are ineligible for oral anticoagulation., Methods: After device implantation for LAAC, different antithrombotic regimens with varying duration of therapy are currently used. Such selection depends on patients' risk for bleeding and physicians' choice., Results: Device-related thrombosis remains an Achilles' heel of LAAC, and the etiology remains incompletely understood. Dual-antiplatelet therapy, and direct oral anticoagulation may have similar safety and device-related thrombosis occurrence in real-world LAAC registries compared with warfarin and aspirin. Device imaging surveillance should be routinely performed to assess for device-related thrombosis, which if diagnosed should be treated aggressively, as it is associated with higher thromboembolic risks., Conclusions: Given the uncertainties and therapeutic dilemma, the authors provide an in-depth discussion of the options and rationale for antithrombotic therapy post-LAAC., (Copyright © 2019. Published by Elsevier Inc.)

Objectives: This study sought to assess the incidence and clinical impact of device related thrombus (DRT) following precautions left atrial appendage occlusion (LAAO)., Background: Device-related thrombus is a known complication of LAAO. However, data on the incidence of DRT and its impact on outcomes are limited., Methods: The authors performed a meta-analysis of randomized and observational studies to calculate the pooled incidence of DRT and the pooled odds ratio (OR) of ischemic events in patients with DRT and those without DRT., Results: In the 66 included studies; the incidence of DRT was 351/10, 153 (3.8%, range 0% to 17%, I 2  = 56.8). The diagnosis was made in <90, 90 to 365, and >365 days in 42%, 57%, and 1% of patients, respectively. There was no difference in DRT rates between the AMPLATZER (AMPLATZER, AGA Medical Corporation, Golden Valley, Minnesota) and WATCHMAN (WATCHMAN, Boston Scientific Corporation, Marlborough, Massachusetts) devices (3.6% vs. 3.1%, p = 0.24). In a meta-regression, age, gender, heart failure, diabetes, CHA 2 DS 2 -VASc score, previous stroke, and post-LAAO antithrombotic regimen did not explain the heterogeneity in the incidence of DRT. The pooled incidence of ischemic events in studies that compared outcomes of patients with and without DRT (32 studies; n = 7,689) was 13.2% (37 of 280) in patients with DRT and 3.8% (285 of 7,399) in those without DRT (OR: 5.27, 95% confidence interval [CI]: 3.66 to 7.59; p < 0.001, I 2  = 0). In a sensitivity analysis including randomized trials and prospective multicenter registries, the incidence of DRT was 3.7%, and DRT remained associated with higher rates of ischemic events (13.5% vs. 4.4%, OR: 4.15, 95% CI: 2.77 to 6.22; p < 0.001, I 2  = 0)., Conclusions: DRT after LAAO is uncommon (3.8%) but is associated with a 4- to 5-fold increase in ischemic events. Further studies are needed to understand the underlying mechanisms and the optimal surveillance and management of DRT., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study investigated characteristics and clinical impact of device-related thrombus formation after Watchman device implantation in atrial fibrillation (AF) patients., Background: Left atrial appendage occlusion using the Watchman device is an effective alternative to anticoagulation for stroke prevention in AF patients. However, device-related thrombus formation remains an important concern after Watchman implantation., Methods: From 2006 to 2014, 119 consecutive AF patients underwent Watchman implantation. Transesophageal echocardiographic (TEE) follow-up was scheduled at 45 days, at 6 months, and at 12 months after the procedure. The incidence, characteristics, and clinical course of device-related thrombus formation detected by TEE were assessed., Results: Follow-up TEE identified thrombus formation on the Watchman device in 4 patients (3.4%). The prevalence of chronic AF was 100% in patients with thrombus, which was higher than that for patients without thrombus (40.0%). Deployed device size was numerically larger in patients with thrombus (29.3 ± 3.8 mm vs. 25.7 ± 3.2 mm, respectively). All patients with thrombus discontinued any of the anticoagulant/antiplatelet therapy which was required under the study protocol. After restarting or continuing warfarin and aspirin therapy, complete resolution of the thrombus was achieved in all patients at subsequent follow-up TEE. Warfarin therapy was discontinued within 6 months for all cases, and there was no thrombus recurrence. The mean follow-up duration was 1,456 ± 546 days, with no death, stroke, or systemic embolization events in patients with thrombus., Conclusions: AF burden, device size, and anticoagulant/antiplatelet regimens can be associated with device-related thrombus after Watchman device implantation. Short-term warfarin therapy was effective, and the clinical outcomes were favorable., (Copyright © 2017 American College of Cardiology Foundation. All rights reserved.)

Background Left atrial appendage occlusion (LAAO) is an alternative to anticoagulation for stroke prevention in select patients with atrial fibrillation (AF). In this study, we describe the case of a patient with delayed device-related thrombus (DRT) at 13 months post-LAAO in a setting of atrial stasis due to a worsening mitral bioprosthetic stenosis. Case summary A 69-year-old woman with a history of rheumatic mitral stenosis and regurgitation post-bioprosthetic mitral valve replacement (6 years prior) and paroxysmal AF was referred for percutaneous LAAO due to recurrent severe gastrointestinal bleeding while on anticoagulation. She underwent an uncomplicated LAAO, for which a 35 mm Watchman Flx device was used. Peri-procedural transoesophageal echocardiogram (TEE) at the time of implant showed thickened and calcified mitral bioprosthetic leaflets and a mild mitral stenosis. Her 45-day post-LAAO TEE showed a mild mitral stenosis and no peri-device leak or DRT. At 12 months, the patient had worsening exertional dyspnoea and pedal oedema. Her 12-month transthoracic echocardiogram (TTE) showed a moderate mitral stenosis and LAAO remained free of DRT. Her symptoms were deemed secondary from a worsening mitral valve stenosis. Mitral valve-in-valve (MViV) replacement was planned because the patient was deemed a prohibitive risk for a redo surgical replacement. Transthoracic echocardiogram on the day of MViV showed a large thrombus on the LAAO device. MViV was postponed. After the patient completed 45 days of anticoagulation with warfarin, a repeat TTE was performed, which showed a resolution of DRT. Transcatheter MViV was performed successfully. Discussion This case demonstrates that increased stasis and left atrial dysfunction from prosthetic mitral stenosis can be a risk factor for late DRT after successful LAAO. The use of a LAAO occlusion device in the presence of a mitral bioprosthesis requires more frequent echocardiographic monitoring to assess both the function of the prosthesis and a delayed formation of thrombus. More studies need to be conducted to assess the safety of percutaneous LAAO devices in those with mitral bioprosthesis. [ABSTRACT FROM AUTHOR]

Introduction: Left atrial appendage closure (LAAC) with Watchman device prevents thromboembolism in patients with atrial fibrillation (AF). However, thrombus may develop on the atrial surface of the device. Aim: To investigate the incidence and predictors of device-related thrombus (DRT) in patients with AF who were treated with LAAC. Material and methods: Ninety-one consecutive patients with AF underwent LAAC procedure using first-generation Watchman 2.5 device followed by antiplatelet therapy. In our analysis we have included all patients (n = 78) who had clinical follow-up visits with transesophageal echocardiography (TEE) after the procedure. Results: The median (IQR) CHA2 DS2 -VASc score was 4 (4.0-6.0) and HAS-BLED score was 3 (3.0-4.0). DRTs were observed in 5 (6.4%) patients. When compared with patients without DRT, those with DRT presented more often with lower median ejection fraction (40% (23.5-45.5) versus 55% (48.0-60.0); p = 0.005), lower emptying velocity of LAA (25 cm/s (17.5-27.0) versus 53 cm/s (26.5-78.0); p = 0.009), and with greater depth of implantation (18 mm (14.0-20.5) versus 8 mm (5.0-11.0); p < 0.001). Furthermore, patients with DRT had greater depth of LAA (35 mm (29.5-41.0) versus 29 mm (25.5-31.0); p = 0.003), greater mean (SD) dimension in 900 (22.4 mm (3.2) versus 19 mm (2.7); p = 0.02). Patients with DRT were also younger than those without DRT (67.4 years (7) versus 75 years (8.3), p = 0.045). Conclusions: The DRT after Watchman device implantation remains a rare complication. Its formation was related to several patient and procedural characteristics, which need to be confirmed in larger studies. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background  Left atrial appendage (LAA) closure with the WATCHMAN device is an alternative to anticoagulation therapy for the prevention of stroke in selected patients with atrial fibrillation (AF). Infrequently, left atrial (LA) device-related thrombus formation occurs and it is poorly understood. Thrombus formation due to incomplete covering of the LAA is even rarer and may occur within the first few months after device implantation. Case summary  Here, we present a case of a 68-year-old male patient with permanent AF, drug- and hepatitis induced liver cirrhosis (CILD Score B), and prior aortic valve replacement. The patient had a history of percutaneous LAA closure using a WATCHMAN device. He developed massive peri-device leak and thrombus arising from the space between the device and appendage cleft 2 years after implantation. Because of the high bleeding risk with a HAS-BLED score of 5 points, surgery was chosen as the therapy of choice instead of long-term anticoagulation. The patient was discharged in good clinical condition and has been scheduled for a yearly follow-up. Discussion  This case emphasizes the importance of choosing appropriately sized LAA occluder devices and planning for regular post-interventional follow-ups to minimize the risk of per-device leaks and thrombi. [ABSTRACT FROM AUTHOR]

Aims Transoesophageal echocardiography studies have reported frequent peri-device leaks and device-related thrombi (DRT) after percutaneous left atrial appendage (LAA) occlusion. We assessed the prevalence, characteristics and correlates of leaks and DRT on cardiac computed tomography (CT) after LAA occlusion. Methods and results Consecutive patients underwent cardiac CT before LAA occlusion to assess left atrial (LA) volume, LAA shape, and landing zone diameter. Follow-up CT was performed after >3 months to assess device implantation criteria, device leaks and DRT. CT findings were related to patient and device characteristics, as well as to outcome during follow-up. One-hundred and seventeen patients (age 74 ± 9, 37% women, CHA2DS2VASc 4.4 ± 1.3, and HASBLED 3.5 ± 1.0) were implanted with Amplatzer cardiac plug (ACP)/Amulet (71%) or Watchman (29%). LAA patency was detected in 44% on arterial phase CT images and 69% on venous phase images. The most common leak location was postero-inferior. LAA patency related to LA dilatation, left ventricular ejection fraction impairment, non-chicken wing LAA shape, large landing zone diameter, incomplete device lobe thrombosis, and disc/lobe misalignment in patients with ACP/Amulet. DRT were detected in 19 (16%), most being laminated and of antero-superior location. DRT did not relate to clinical or imaging characteristics nor to implantation criteria, but to total thrombosis of device lobe. Over a mean 13 months follow-up, stroke/transient ischaemic attack occurred in eight patients, unrelated to DRT or LAA patency. Conclusion LAA patency on CT is common after LAA occlusion, particularly on venous phase images. Leaks relate to LA/LAA size at baseline, and device malposition and incomplete thrombosis at follow-up. DRT is also quite common but poorly predicted by patient and device-related factors. [ABSTRACT FROM AUTHOR]

A 75-year-old woman with a history of atrial fibrillation, severe biatrial enlargement, persistent dense spontaneous echo contrast in the left atrium and left-atrial appendage on appropriate oral anticoagulant therapy underwent implantation of the left-atrial occlusion device to decrease her risk of thromboembolic stroke. Six weeks later, a scheduled transesophageal echocardiography showed a partially mobile mass (4.1 × 2.1 cm) overlying the atrial surface of the device: a suspected thrombus. This report highlights the importance of follow-up examination and the limitation of this treatment modality among patients with persistent atrial fibrillation, large left atria and dense spontaneous echo contrast. Copyright © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]