Thrombus Formation After Left Atrial Appendage Occlusion With the Amplatzer Amulet Device

Twice-daily rivaroxaban after percutaneous left atrial appendage closure for atrial fibrillation

Background and aim: Rivaroxaban is an emerging oral anticoagulant for postoperative anticoagulation after percutaneous left atrial appendage closure (LAAC). Because a once-daily dosing regimen of rivaroxaban causes fluctuations in the drug plasma concentration, we studied the feasibility and safety of twice-daily rivaroxaban as a postoperative anticoagulation regimen for patients with atrial fibrillation (AF) undergoing LAAC. Methods: This study involved patients with AF who underwent LAAC and took rivaroxaban postoperatively. A total of 326 patients who received a standard total dose (15 or 20 mg) of rivaroxaban based on their creatinine clearance rate were divided into the twice-daily (BID) rivaroxaban group (n = 208) and once-daily (QD) rivaroxaban group (n = 118) according to their anticoagulation strategy. Transesophageal echocardiography was recommended at 3-6 months postoperatively to check for device-related thrombosis (DRT). Clinical outcomes were evaluated during postoperative anticoagulation. Results: The median CHA2DS2-VASc score (4 [3, 5] vs. 4 [3, 5], p = 0.28) and HAS-BLED score (2 [2, 3] vs. 2 [2, 3], p = 0.48) were not significantly different between the groups. During the anticoagulation period (4.1 ± 0.7 vs. 4.1 ± 0.9 months, p = 0.58), 148 (71.2%) patients in the BID group and 75 (63.6%) in the QD group underwent follow-up transesophageal echocardiography. There were no statistically significant differences between the two groups in terms of DRT (1.4% vs. 2.7%, p = 0.60), minor bleeding (8.2% vs. 11.0%, p = 0.39), thromboembolic events (1.0% vs. 0.8%, p = 1.00), major bleeding (0.5% vs. 0.8%, p = 1.00), or death. Conclusion: A short course of twice-daily rivaroxaban following LAAC is a feasible alternative regimen with a low rate of major bleeding events, DRT, and thromboembolic events for patients with AF.

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.

Cardiogeriatrics: the current state of the art

It is estimated that by 2050, 17% of the world's population will be greater than 85 years old, which, combined with cardiovascular disease (CVD) being the leading cause of death and disability, sets an unprecedented burden on our health and care systems. This perfect storm will be accompanied by a rise in the prevalence of CVD due to increased survival of patients with pre-existing CVD and the incidence of CVD that is associated with the process of ageing. In this review, we will focus on the diagnosis and management of common CVD conditions in old age, namely: heart failure (HF), coronary artery disease (CAD), atrial fibrillation (AF) and valvular heart disease (VHD). Despite limited evidence, clinical guidelines are increasingly considering the complexity of management of these conditions in the older person, which often coexist, for example, AF and HF or CAD and VHD. Furthermore, they, in turn, need specific consideration in the context of comorbidities, polypharmacy, frailty and impaired cognition found in this age group. Hence, the emerging role of the geriatric cardiologist is therefore vital in performing comprehensive geriatric assessment, attending multidisciplinary team meetings and ultimately considering the patient and the sum of their diseases in their totality. There have been recent advances in CVD management but how we apply these to deliver integrated care to the elderly population is key. This review article aims to bring together emerging studies and guidelines on assessment and management of CVD in the elderly, summarising latest definitions, diagnostics, therapeutics and future challenges.

Clinical Implications of CT-detected Hypoattenuation Thickening on Left Atrial Appendage Occlusion Devices

Background At follow-up CT after left atrial appendage occlusion (LAAO), hypoattenuation thickening (HAT) on the atrial aspect of the device is a common finding but the clinical implications require further study. Purpose To assess the association of HAT grade at follow-up CT with clinical characteristics and outcomes in patients who underwent LAAO. Materials and Methods This prospective study included consecutive participants with atrial fibrillation and who were at high risk for stroke (CHA2DS2-VASc score ≥4) who underwent LAAO and were administered pacifier or nonpacifier devices at two French medical centers between January 2012 and November 2020. Postprocedure CT images were evaluated by two radiologists in consensus and device-specific interpretation algorithms were applied to classify HAT as low grade (low suspicion of thrombosis) or high grade (high suspicion of thrombosis). The association between HAT grade and clinical characteristics was assessed using multinomial logistic regression, and variables associated with risk of stroke were assessed using a Cox proportional hazard model. Results This study included 412 participants (mean age, 76 years ± 8 [SD]; 284 male participants) who underwent follow-up CT at a mean of 4.2 months ± 1.7 after LAAO. Low-grade and high-grade HAT were depicted in 98 of 412 (23.8%) and 21 of 412 (5.1%) participants, respectively. High-grade HAT was associated with higher odds of antithrombotic drug discontinuation during follow-up (odds ratio, 9.5; 95% CI: 3.1, 29.1; P < .001), whereas low-grade HAT was associated with lower odds of persisting left atrial appendage patency (odds ratio, 0.46; 95% CI: 0.27, 0.79; P = .005). During a median follow-up of 17 months (IQR, 11-41 months), stroke occurred in 24 of 412 (5.8%) participants. High-grade HAT was associated with stroke (hazard ratio, 4.6; 95% CI: 1.5, 14.0; P = .008) and low-grade HAT (P = .62) was not. Conclusion Low-grade HAT was a more common finding at CT performed after LAAO CT (24%) than was high-grade HAT (5%), but it was associated with more favorable outcomes than high-grade HAT, which was associated with higher stroke risk. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Choe in this issue.

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.

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.

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.

Intra- and Postprocedural Multimodality Imaging in Atrial Fibrillation

Multi-modality imaging plays critical roles during and after procedures associated with atrial fibrillation. Transesophageal echocardiography is an invaluable tool for left atrial appendage occlusion during the procedure and at follow-up. Both cardiac computed tomography and cardiac magnetic resonance contribute to postprocedural evaluation of pulmonary vein isolation ablation. The present review is the second of a 2-part series where we discuss the roles of cardiac imaging in the evaluation and management of patients with atrial fibrillation, focusing on intraprocedural and postprocedural assessment, including the clinical evidence and outcomes data supporting this future applications.

Left atrial appendage exclusion in atrial fibrillation

Although oral anticoagulants (OACs) are first-line therapy for stroke prevention in patients with atrial fibrillation (AF), some patients cannot be treated with OACs due to absolute or relative contraindications. Left atrial appendage (LAA) exclusion techniques have been developed over the years as a therapeutic alternative for stroke prevention. In this paper, we review the evolution of surgical techniques, employed as an adjunct to cardiac surgery or as a stand-alone procedure, as well as the recently introduced and widely utilized percutaneous LAA occlusion techniques. Until recently, data on surgical LAAO were limited and based on non-randomized studies. We focus on recently published randomized data which strongly support an add-on surgical LAAO in eligible patients during cardiac surgery and could potentially change current practice guidelines. In recent years, the trans-catheter techniques for LAA occlusion have emerged as another, less invasive alternative for patients who cannot tolerate oral anticoagulation. We review the growing body of evidence from prospective studies and registries, focusing on the two systems which are in widespread clinical use nowadays: the Watchman and Amulet type devices. These data show favorable results for both Watchman and Amulet devices, setting them as an important tool in our arsenal for stroke reduction in AF patients, especially in those who have contraindications for OACs. A better understanding of the different therapeutic alternatives, their specific benefits, and downfalls in different patient populations can guide us in tailoring the optimal therapeutic approach for stroke reduction in our AF patients.

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.

Left Atrial Spontaneous Echo Contrast and Ischemic Stroke in Patients Undergoing Percutaneous Left Atrial Appendage Closure

Objectives: Spontaneous echo contrast (SEC) in the left atrium (LA) is frequently observed in atrial fibrillation (AF) patients and may lead to thromboembolic events. We aimed to investigate both periprocedural and long-term stroke risks associated with LA SEC in AF patients undergoing percutaneous left atrial appendage closure (LAAC). Methods: A total of 408 consecutive AF patients treated with LAAC between March 2015 and February 2019 were divided into two groups based on preprocedural transesophageal echocardiography: the study group (moderate/severe LA SEC; n = 41) and the control group (none, mild, or mild to moderate LA SEC; n = 367). To attenuate the observed imbalance in baseline covariates, a propensity score matching technique was used. Results: No periprocedural stroke/transient ischemic attack (TIA) was documented. The incidence of device-related thrombus was higher in the study group than in the control group (8.8 vs. 1.3%; P = 0.025). The mean follow-up period was 3.2 ± 1.1 years, during which 8 patients (2.2%) in the control group and 4 (9.8%) in the study group experienced stroke/TIA (P = 0.024). Moderate/severe LA SEC was identified as an independent predictor of stroke/TIA in both the original population (HR = 5.71, 95% CI 1.47-22.19, P = 0.012) and the matched population (HR = 9.79, 95% CI 1.44-66.86, P = 0.020). Conclusions: LA SEC did not show a relationship with periprocedural stroke events in patients undergoing percutaneous LAAC. However, moderate/severe LA SEC increased the incidence of device-related thrombus and the risk of late stroke/TIA.

Multiple systemic paradoxical embolisation of a lower limb deep vein thrombosis due to interatrial septal puncture: a rare complication of left atrial appendage occlusion

A 75-year-old woman with a history of intracranial haemorrhage, atrial fibrillation and coronary artery bypass graft underwent elective left atrial appendage occlusion (LAAO) for stroke prevention. The procedure was successful, however on the third postoperative day, she presented with a lymph leak at the right femoral venous access site. She was admitted for conservative management of the lymph leak with immobility and intravenous fluids. Her inpatient stay was complicated by a right lower limb deep vein thrombosis (DVT), left middle cerebral artery territory ischaemic stroke, pulmonary emboli (PEs) and a splenic infarction. The mechanism of the systemic emboli was that of paradoxical emboli from the DVT passing through an interatrial septal defect created as part of the LAAO procedure, a previously unreported complication of LAAO. She was managed with 6 months of low-dose oral anticoagulation for treatment of DVT and PE and has made a full neurological recovery.

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].

One year outcome and analysis of peri-device leak of left atrial appendage occlusion devices

BACKGROUND

The prevalence of peri-device leak (PDL) of left atrial appendage occlusion (LAAO) devices has been previously reported. However, there have been only few data that compared different existing devices. The aim of this study was to assess the incidence of PDL with both devices WATCHMAN®, Boston Scientific and AMPLATZER Amulet®, Abbott Laboratories and to evaluate the clinical outcome at 12 months.

METHODS

Consecutive patients who underwent LAAO between January 2018 and 2020 were randomly assigned to either WATCHMAN or AMPLATZER Amulet implantation based on a systematic 2-week alternation between both devices. LAA measurements were assessed using cardiac computed tomography angiography (CCTA) prior to and transesophageal echocardiography (TEE) during the procedure. At 8 weeks post-LAAO, patients underwent TEE and/or CCTA to identify the presence of PDL and/or device-related complications. Patients were then followed for 12 months to identify major adverse cardiovascular/embolic events.

RESULTS

The cohort consisted of 51 patients (25 WATCHMAN, 26 AMPLATZER Amulet; mean age 76 ± 7 years; male gender 76%). Both groups were identically matched for demographics, comorbidities, and indication for LAAO. There were 19 patients who had PDL (13 WATCHMAN vs. 6 AMPLATZER Amulet, P-value = 0.033). Of them, 8 (15%) patients had significant PDL (7 WATCHMAN vs. 1 AMPLATZER Amulet, P-value = 0.018). On CCTA, the landing zone maximal diameter of the AMPLATZER Amulet device had the strongest correlation with the final deployed device size (Spearman's rho 0.92, P-value < 0.0001). In the multivariate analysis, male gender and device type were independent predictors of any PDL (P-values 0.016 and 0.031, respectively). On a mean follow-up of 12 months, the total number of events was more prevalent in the WATCHMAN group (P-value 0.008), but the incidence of cardio-embolic events reached borderline significance (16% vs. 0%, P-value = 0.051).

CONCLUSIONS

Among patients who underwent LAAO, almost 15% had significant PDL with the majority belonging to the WATCHMAN group. Still, larger studies are warranted to evaluate its effectiveness in stroke prevention.

Percutaneous Occlusion of the Left Atrial Appendage with Thrombus Irresponsive to Antithrombotic Therapy

We analyzed clinical experience with percutaneous closure of instances of left atrial appendage with thrombus (LAAT) irresponsive to antithrombotic therapy in patients treated in three high-volume cardiology centers. Clinical and procedural data regarding consecutive patients who underwent percutaneous left atrial appendage closure (PLAAC) due to LAAT were retrospectively analyzed. The study population consisted of 17 patients (11 men; 68 ± 14 years; CHA₂DS₂VASC 4.7 ± 1.9; HASBLED 3 (0-5)) with LAAT confirmed by transesophageal echocardiography, and included 5 patients with mechanical heart valves. Most of the patients (94.1%) received anticoagulation therapy before PLAAC. All LAATs were located in distal portions of the appendage and occupied less than 30% of its volume. Occluding-device implantation was successful in 17 patients; in one, a residual leak was disclosed. Appropriate positioning of occluders required more than 1 attempt in 6 individuals (35.3%); in 3 others (17.6%), the subjects' devices had contact with thrombi. No procedural complications were noted. Midterm follow-up (median: 10 months) revealed no procedure-related complications or clinically diagnosed thromboembolism. Transesophageal echocardiography (TEE) performed after six months revealed device-related thrombus in one patient. We concluded that LAAT irresponsive to antithrombotic therapy might be effectively treated with PLAAC, even in patients with mechanical-valve prostheses.

Why Follow-up Examinations After Left Atrial Appendage Closure Are Important: Detection of Complications During Follow-up and How to Deal with Them

PURPOSE OF REVIEW

Device-related thrombus (DRT) formation and incomplete left atrial appendage closure (LAAC) are the two major complications that can occur after LAAC and can potentially limit the success of such a procedure. This review discusses the incidence, clinical and/or prognostic significance, detection methods, treatment options, and potential strategies to prevent these complications.

RECENT FINDINGS

It has recently been proven that the presence of a DRT represents an independent predictor for ischemic stroke after LAAC. Continued need for anticoagulation due to incomplete LAAC is clinically relevant to the patient. The appearances of a DRT or an incompletely closed LAA after a LAAC procedure are not rare complications. Due to the clinical and/or prognostic significance of these complications, it is important to detect them in a timely manner during follow-up by using the appropriate diagnostic imaging techniques. Since a DRT is associated with an increased risk of stroke, the therapy should be aggressive. In the case of incomplete LAA closure, an additional closure device may be used to complete occlusion and avoid lifelong anticoagulation therapy.

Short-Term Oral Anticoagulation Versus Antiplatelet Therapy Following Transcatheter Left Atrial Appendage Closure

Background:

The impact of antithrombotic therapy on coagulation system activation after left atrial appendage closure (LAAC) remains unknown. This study sought to compare changes in coagulation markers associated with short-term oral anticoagulation (OAC) versus antiplatelet therapy (APT) following LAAC.

Methods:

Prospective study including 78 atrial fibrillation patients undergoing LAAC with the Watchman device. F1+2 (prothrombin fragment 1+2) and TAT (thrombin-antithrombin III) were assessed immediately before the procedure, and at 7, 30, and 180 days after LAAC.

Results:

Forty-eight patients were discharged on APT (dual: 31, single: 17) and 30 on OAC (direct anticoagulants: 26, vitamin K antagonists: 4), with no differences in baseline-procedural characteristics between groups except for higher spontaneous echocardiography contrast in the OAC group. OAC significantly reduced coagulation activation within 7 days post-LAAC compared with APT (23% [95% CI, 5%–41%] versus 82% [95% CI, 54%–111%] increase for F1+2, P =0.007; 52% [95% CI, 15%–89%] versus 183% [95% CI, 118%–248%] increase for TAT, P =0.048), with all patients in both groups progressively returning to baseline values at 30 and 180 days. Spontaneous echocardiography contrast pre-LAAC was associated with an enhanced activation of the coagulation system post-LAAC (144 [48–192] versus 52 [24–111] nmol/L, P =0.062 for F1+2; 299 [254–390] versus 78 [19–240] ng/mL, P =0.002 for TAT). Device-related thrombosis occurred in 5 patients (6.4%), and all of them were receiving APT at the time of transesophageal echocardiography (10.2% versus 0% if OAC at the time of transesophageal echocardiography, P =0.151). Patients with device thrombosis exhibited a greater coagulation activation 7 days post-LAAC ( P =0.038 and P =0.108 for F1+2 and TAT, respectively).

Conclusions:

OAC (versus APT) was associated with a significant attenuation of coagulation system activation post-LAAC. Spontaneous echocardiography contrast pre-LAAC associated with enhanced coagulation activation post-LAAC, which in turn increased the risk of device thrombosis. These results highlight the urgent need for randomized trials comparing OAC versus APT post-LAAC.

Short-Term Antiplatelet Versus Anticoagulant Therapy After Left Atrial Appendage Occlusion: A Systematic Review and Meta-Analysis

OBJECTIVES

The aim of this study was to compare bleeding, thromboembolic, device-related thrombus (DRT), and all-cause mortality events between patients treated with short-term oral anticoagulation (OAC) and those treated with short-term antiplatelet therapy (APT) following left atrial appendage occlusion (LAAO).

BACKGROUND

Short-term OAC is recommended for patients following LAAO. However, in practice many patients receive APT rather than OAC because of excessive bleeding risk. However, the safety and efficacy of APT compared with OAC have been debated.

METHODS

A search was conducted of databases for studies comparing OAC with APT following LAAO. The outcomes of interest were all-cause stroke, major bleeding, DRT, and all-cause mortality. Noncomparative studies were pooled into a single study to generate comparisons of the studies' outcomes. Effects measure were pooled using the random-effect model.

RESULTS

A total of 83 studies with 12,326 patients (APT, n = 7,900; OAC, n = 4,151) were included. Mean CHA2DS2-VASc and HAS-BLED scores were 4.1 ± 1.6 and 3.0 ± 1.3, respectively. There were no significance differences between the APT and OAC groups with regard to stroke (risk ratio [RR]: 1.04; 95% confidence interval [CI]: 0.54 to 1.98; p = 0.91; I2 = 31%), major bleeding (RR: 1.12; 95% CI: 0.68 to 1.84; p = 0.65; I2 = 53%), DRT (RR: 1.33; 95% CI: 0.74 to 2.39; p = 0.33; I2 = 36%), and all-cause mortality (RR: 1.29; 95% CI: 0.40 to 4.09; p = 0.18; I2 = 36%). These findings persisted in multiple secondary analyses: 1) excluding studies that reported no events; 2) including comparative studies only; 3) excluding patients who were treated with single APT; and 4) removing one study at a time to assess the effect of each study on the overall effect size. There was also no difference in the studies' endpoints among patients who received different LAAO devices.

CONCLUSIONS

In a meta-analysis of observational data, there were no differences in the occurrence of stroke, major bleeding DRT, and all-cause mortality in patients treated with short-term OAC or APT following LAAO.

Clinical outcomes and thrombus resolution in patients with solid left atrial appendage thrombi: results of a single-center real-world registry

BACKGROUND

Data on thrombus resolution and clinical outcome data after a therapy of LAA thrombus with novel oral anticoagulants (NOACs) are scarce.

METHODS

In this single-center study, we retrospectively analyzed 78 patients diagnosed with a solid LAA thrombus by transesophageal echocardiography (TEE). We assessed baseline clinical and echocardiographic characteristics, the anticoagulatory regimens and outcomes of patients with (responders) and without (non-responders) thrombus resolution.

RESULTS

Mean age was 76.1 ± 8.3 years, patients were male in 57.7% and presented with a high risk for thromboembolism (CHA₂DS₂-VASc: 4.3 ± 1.1). At thrombus diagnosis, 44.9% patients were treated with a NOAC, while 41.0% were under therapy with a VKA. Complete thrombus resolution was achieved after a mean of 116 ± 79 days in a total of 51.3% of patients, 35.9% showed a reduction of thrombus size, whereas 12.8% showed no changes in thrombus dimensions. There was no statistically significant difference in the rate of LAA thrombus resolution between VKA and NOACs (41.2 vs. 57.1%, p = 0.18). However, in cases in which only the therapy with a NOAC led to complete thrombus resolution, the time needed was significantly shorter than with VKA (81 ± 38 vs. 129 ± 46 days, p = 0.03). Regarding safety outcomes, no differences in bleeding or thromboembolism were observed between patients with and without thrombus resolution.

CONCLUSIONS

In this registry, approximately 85% of LAA thrombi were diagnosed in patients with ongoing OAC. Thrombus resolution was observed in nearly 50% of cases. Although there was no difference in the rate of LAA thrombus resolution between VKA and NOACs, the resolution time was shorter in patients prescribed a NOAC.

Antithrombotic Therapy for Percutaneous Cardiovascular Interventions: From Coronary Artery Disease to Structural Heart Interventions

Percutaneous cardiovascular interventions have changed dramatically in recent years, and the impetus given by the rapid implementation of novel techniques and devices have been mirrored by a refinement of antithrombotic strategies for secondary prevention, which have been supported by a significant burden of evidence from clinical studies. In the current manuscript, we aim to provide a comprehensive, yet pragmatic, revision of the current available evidence regarding antithrombotic strategies in the domain of percutaneous cardiovascular interventions. We revise the evidence regarding antithrombotic therapy for secondary prevention in coronary artery disease and stent implantation, the complex interrelation between antiplatelet and anticoagulant therapy in patients undergoing percutaneous coronary intervention with concomitant atrial fibrillation, and finally focus on the novel developments in the secondary prevention after structural heart disease intervention. A special focus on treatment individualization is included to emphasize risk and benefits of each therapeutic strategy.

Antithrombotic/Antiplatelet Treatment in Transcatheter Structural Cardiac Interventions-PFO/ASD/LAA Occluder and Interatrial Shunt Devices

Transcatheter interventions enable safe and efficient treatment of various structural heart diseases. However, therapy does not finished with the end of the procedure. Device thrombosis is a possible serious complication. Therefore, careful patient management should include optimal antiplatelet or antithrombotic medication to enhance safe and complete endothelial coverage of the implanted device. In case of thrombus formation careful diagnostic evaluation and prompt treatment is crucial. This paper provides an update to current knowledge and understanding of prevention and management of device related thrombosis.

Left atrial appendage patency and device-related thrombus after percutaneous left atrial appendage occlusion: a computed tomography study

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.

Real-world survival data of device-related thrombus following left atrial appendage closure: 4-year experience from a single center

This study aimed to estimate the incidence and risk factors of device-related thrombus (DRT) following percutaneous left atrial appendage closure (LAAC) in real-world practices. Between February 2012 and December 2016, 319 consecutive patients with atrial fibrillation underwent percutaneous LAAC using WATCHMAN, WATCHMAN Flx, Amplatzer cardiac plug, and Amulet devices. All patients underwent transesophageal echocardiography (TEE) at a minimum of three time points; periprocedurally, at 45 days, and at 6 months. Other clinical parameters were also evaluated, and a comparison between patients with DRT and those not suffering from DRT was done. The percutaneous LAAC was successfully performed in 97.8% of the patients. DRT was detected in 14 (4.49%) patients; of the 14 patients, DRT was detected in 3 patients at acute phase, 8 patients at subacute phase, 2 patients at late phase and 1 patient at very late phase. Most of the DRT originated from the central screw of device. In 6 out of 14 patients, DRT was successfully resolved by oral anticoagulation. Higher HAS-BLED score (4.1 ± 1.2 vs. 3.5 ± 1.1, p = 0.042) was more frequent in patients with DRT. Multivariable analysis showed that residual peri-device leak may result in a predisposition to DRT (p = 0.023). The incidence of DRT after percutaneous LAAC was acceptable, as a part of the DRT was resolved with oral anticoagulation. Residual peri-device leak was associated with DRT. Optimal implantation without peri-device gap, individual antithrombotic regimens, and careful monitoring with TEE follow-up could be conducive to the prevention of DRT.

Device-Related Thrombus After Left Atrial Appendage Occlusion With the Amulet Device

BACKGROUND

Left atrial appendage occlusion (LAAO) is increasingly used for stroke prevention in patients with atrial fibrillation who are considered unsuitable for a lifelong oral anticoagulant regimen. Recently, a single-centre study reported device-related thrombus formation in 16.7% of patients treated with the second-generation Amulet device (St. Jude Medical, St. Paul, MN, USA), presenting a potential major safety concern. As "real-world" data on device-related thrombus formation following LAAO with the Amulet occluder are scarce, we aimed to evaluate this outcome in a retrospective registry.

METHODS

Clinical and tranosesophageal echocardiography data after LAAO with the Amulet in consecutive patients from three centres were collated.

RESULTS

Among 38 patients (mean age 75.8 years), mean (standard deviation) CHA₂DS₂-VASc and HAS-BLED scores were 4.4 (1.2) and 3.4 (0.9), respectively. All patients underwent successful device placement without procedure-related adverse events. The antithrombotic regimen at discharge consisted of dual antiplatelet therapy (DAPT) in 27 patients (71.1%), single antiplatelet therapy in 10 patients (26.3%), and no antithrombotic therapy in one patient (2.6%). Device-related thrombus was observed in one patient (2.6%) despite DAPT regimen. The outcome of this patient was uncomplicated after adjustment of oral anticoagulant therapy. No patients presented with a thromboembolic event following LAAO during a mean (standard deviation) follow-up of 15 (5) months.

CONCLUSIONS

In this retrospective study, device-related thrombus formation with the second-generation Amulet device was rare and occurred at a rate similar to that of the previous device. Importantly, no patient experienced a device-related thromboembolic event during follow-up. Larger real-life studies are required to confirm the safety profile of this increasingly used device.

[Catheter-based atrial appendage closure-current data and future developments]

In Germany more than 1.6 million patients suffer from atrial fibrillation (AF). Within the next decades this number will substantially increase due to current demographic trends with the increasing average age of the population. When untreated, patients with atrial fibrillation have a five times higher risk for stroke as compared with a control cohort. A potent stroke prevention therapy reducing the risk of stroke by approximately 70-80% is primarily treatment with new oral anticoagulants (NOACs). The risk scores for stroke (CHA₂DS₂-VASc) and major bleeding (HAS-BLED) in patients with atrial fibrillation share common variables, so that patients with the highest stroke risk often carry a very high bleeding risk. A significant number of patients (ca. 20-30%) are, however, not eligible for long-term anticoagulation, e.g. because of a high bleeding risk. For this population there is an urgent need for alternative stroke prevention strategies, such as catheter-based percutaneous left atrial appendage closure. Current data about the efficiency and safety of this treatment as well as a discussion of ongoing recruitment for randomized studies are discussed in this review.

Safety and feasibility of interventional left atrial appendage closure without contrast agent

AIMS

Interventional left atrial appendage closure (LAAC) is routinely performed under both echocardiographic and angiographic guiding. However, adverse outcomes, e.g., kidney injury and cerebral embolism, might be associated with injections of contrast agent into the LAA. Therefore, this prospective registry investigated the safety and feasibility of LAAC without the support of angiographic images as the default approach.

METHODS AND RESULTS

This single-centre registry included a total of 46 non-selected, consecutive patients. In the first 25 patients (54%), LAAC with the Amulet device was performed routinely with LAA angiography prior to implantation and after release of the device. The following 21 patients (46%) were treated without the use of contrast agent. The combination of successful implantation and lack of procedural complications was regarded as the primary endpoint. Procedure time, number of recapture manoeuvres, change of device size, compression, leakage, dose area product and late thrombosis on the device were investigated as secondary endpoints. Besides the longer fluoroscopy time and duration of the procedure in the group using angiography, no significant differences could be found. Major complications occurred equally often in both cohorts.

CONCLUSIONS

Interventional LAAC with the Amulet device can be performed safely without the use of contrast agent. This approach might help to enhance the use of LAAC in patients at high risk of contrast-induced nephropathy and procedural stroke.

[Oral anticoagulation and platelet inhibition after atrial appendage occlusion]

In Europe left atrial appendage occluders (LAAO) are most frequently used in patients with contraindications for oral anticoagulation (OAC); therefore, the classical therapeutic OAC scheme from the PROTECT-AF trial (vitamin K antagonist plus acetylsalicylic acid) is usually changed to dual anti-platelet therapy (DAPT) after implantation of a Watchman® or Amulet® LAAO (St. Jude Medical/Abbott, Eschborn, Germany). For many years, patients with an LAAO received DAPT for 1-6 months. The current standard comprises DAPT for 3 months, followed by permanent acetylsalicylic acid monotherapy if the transesophageal echocardiogram excludes a thrombus at the site of the LAAO. In patients with high risk of bleeding, anti-platelet therapy can be stopped at 3 months after an individual risk-benefit calculation. There are no randomized studies on the risk of bleeding and stroke/embolism in patients with an LAA occluder under DAPT versus OAC. Experience from the EWOLUTION registry shows that NOACs may be used as an alternative with low bleeding and thrombus risks. In patients with a suboptimal implantation result, thrombus on the LAAO or specific risk factors, variations of the standard scheme have to be applied and if necessary lifelong DAPT or NOAC therapy has to be used. Thrombi on the LAAO occur in approximately 4-6% of patients and are associated with a very low short-term stroke risk.