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

Left atrial appendage closure for stroke prevention in atrial fibrillation: current status and perspectives

Atrial fibrillation (AF) is associated with an increased risk of stroke and systemic embolism, and the left atrial appendage (LAA) has been identified as a principal source of thromboembolism in these patients. While oral anticoagulation is the current standard of care, LAA closure (LAAC) emerges as an alternative or complementary treatment approach to reduce the risk of stroke or systemic embolism in patients with AF. Moderate-sized randomized clinical studies have provided data for the efficacy and safety of catheter-based LAAC, largely compared with vitamin K antagonists. LAA device iterations, advances in pre- and peri-procedural imaging, and implantation techniques continue to increase the efficacy and safety of LAAC. More data about efficacy and safety of LAAC have been collected, and several randomized clinical trials are currently underway to compare LAAC with best medical care (including non-vitamin K antagonist oral anticoagulants) in different clinical settings. Surgical LAAC in patients with AF undergoing cardiac surgery reduced the risk of stroke on background of anticoagulation therapy in the LAAOS III study. In this review, we describe the rapidly evolving field of LAAC and discuss recent clinical data, ongoing studies, open questions, and current limitations of LAAC.

Antithrombotic therapy for transcatheter structural heart intervention

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

Early Nonprocedural Bleeding After Left Atrial Appendage Occlusion

BACKGROUND

Patients treated with left atrial appendage occlusion (LAAO) are at high bleeding risk. Intensive antithrombotic treatment is recommended after the procedure to prevent device-related thrombosis.

OBJECTIVES

This study sought to evaluate the incidence, consequences, and predictors of early nonprocedural bleeding after LAAO.

METHODS

This was a multicenter study including 1,649 patients undergoing LAAO in 9 centers. Early nonprocedural bleeding was defined as bleeding unrelated to the procedure occurring within 3 months after device implantation. The severity of bleeding was defined by the Valve Academic Research Consortium-2 classification. A sensitivity analysis was performed at 45 days.

RESULTS

A total of 121 (7.3%) patients experienced early nonprocedural bleeding events, and 69 (57.0%) were classified as major bleeding (4.2% of patients). Independent predictors of early nonprocedural bleeding were dual antiplatelet therapy (DAPT) at discharge (adjusted HR [aHR]: 1.61; 95% CI: 1.12-2.33; P = 0.01), prior gastrointestinal bleeding (aHR: 2.15; 95% CI: 1.38-3.35; P < 0.001), and multiple locations of prior bleeding (aHR: 2.33; 95% CI: 1.34-4.05; P < 0.001). DAPT at discharge was predictive of both all and major nonprocedural bleeding at 3 months and 45 days. After a median follow-up of 2.3 years (Q1-Q3: 1.1-4.1 years), early nonprocedural bleeding was independently associated with an increased risk of all-cause death (aHR: 1.53; 95% CI: 1.15-2.06; P < 0.001). This heightened mortality risk was similar at 45 days.

CONCLUSIONS

Early nonprocedural bleeding after LAAO occurred in ∼7% of patients within 3 months, with more than one-half being classified as major bleeding. Regardless of severity, early nonprocedural bleeding was associated with increased mortality. DAPT at discharge determined an increased risk of early nonprocedural bleeding after LAAO. These results emphasize the importance of bleeding risk for determining antithrombotic strategies after LAAO.

Impact of gender in patients with device-related thrombosis after left atrial appendage closure - A sub-analysis from the multicenter EUROC-DRT-registry

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.

Impact of chronic kidney disease on left atrial appendage occlusion: A meta-analysis of procedural outcomes and complications

BACKGROUND

Patients with chronic kidney disease (CKD) experience atrial fibrillation more frequently. The balance of medical management for stroke prevention and bleeding events presents a challenging issue in CKD population. Left atrial appendage occlusion (LAAO) may be an effective solution for stroke prevention in patients who experience frequent bleeding with oral anticoagulants. However, the specific impact of CKD on the procedural success, complications, and outcomes of LAAO implantations remains underexplored.

METHODS

We conducted a search of various databases for articles published before October 31, 2023. This search yielded 7 studies, comparing outcomes between CKD and non-CKD cohorts undergoing LAAO implantation. Our analysis focused on CHA2DS2-VASc scores, average eGFR, use of oral anticoagulants, procedural success rates, procedural complications, and associated outcomes.

RESULTS

The meta-analysis included data from 2576 patients, with 1131 identified as having CKD. The CKD group also had higher CHA2DS2-VASc scores (4.7 ± 1.4 vs 4.0 ± 1.5; P < .001) and HAS-BLED scores (3.8 ± 1.1 vs 3.1 ± 1.0; P < .001) than the non-CKD group. CKD patients showed a nonreduction in procedural success rates and a nonsignificant increase in total complications. The risks of stroke and transient ischemic attack, major bleeding, and cardiovascular mortality were not significantly different between the 2 groups. However, a significantly lower rate of total mortality was observed in the non-CKD group (odds ratio: 0.43; 95% confidence interval, 0.32-0.60).

CONCLUSION

While CKD is associated with a nonsignificant decrease in procedural success and a nonsignificant increase in complication risks, the outcomes of LAAO implantation are comparably favorable between CKD and non-CKD groups. Despite similar procedural outcomes, the CKD group exhibited a higher rate of all-cause mortality.

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

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

Comparative Data of Procedural and Midterm Outcomes in Patients Who Underwent Percutaneous Left Atrial Appendage Closure Between the WATCHMAN FLX and WATCHMAN 2.5 Devices - Insight From the OCEAN-LAAC Registry

BACKGROUND

Limited data are available regarding clinical outcomes after percutaneous left atrial appendage closure using WATCHMAN FLX (WM-FLX) and WATCHMAN-2.5 (WM2.5) devices in Asian patients.

METHODS AND RESULTS

Data of 1,464 consecutive patients (WM-FLX, n=909; WM2.5, n=555) were extracted from a Japanese multicenter registry, and clinical data were compared between the 2 groups. No in-hospital deaths, periprocedural stroke, or device embolization occurred. Procedural success was significantly higher in the WM-FLX than WM2.5 group (95.8% vs. 91.9%; P=0.002) owing to the lower incidence of periprocedural pericardial effusion (0.55% vs. 1.8%; P=0.021). No significant differences in all-cause death, postprocedural stroke, and device-related thrombus were observed between the 2 groups. However, the cumulative bleeding rate at 1 year was substantially lower in the WM-FLX group (7.8% vs. 16.4%; P<0.001). Landmark analysis of bleeding events highlighted lower bleeding rates in the WM-FLX than WM2.5 group within the first 6 months (6.4% vs. 14.8%; P<0.001), with comparable bleeding rates over the 6- to 12-month period (1.5% vs. 3.2%, respectively; P=0.065).

CONCLUSIONS

This study demonstrated higher early safety and lower 1-year bleeding rates in the WM-FLX than WM2.5 group. The lower bleeding events with WM-FLX are likely due to multiple factors other than purely difference in devices, such as postprocedural drug regimen.

Peri-device leakage and delayed endothelialization of the Watchman device: a computed tomography study

OBJECTIVES

This study aimed to explore the endothelialization process and assess the potential association between endothelialization and peri-device leak (PDL) following Watchman implantation via a quantitative method.

METHODS

This is a single-center retrospective study of consecutive patients undergoing LAAO between December 2015 and November 2021. Device endothelialization, compared between PDL and non-PDL group, were quantitatively analyzed based on hypoattenuated thickening in cardiac computed tomography angiography (CCTA). Advancement in endothelialization over time were explored using the Cochran-Armitage test and generalized estimating equation approach. Potential risk factors of delayed endothelialization were analyzed using the Cox proportional-hazards model.

RESULTS

A total of 172 patients (mean age, 68 years ± 10 [standard deviation], 114 men) were finally included. The average endothelialization ratio of the study population was 89.8 ± 7.2 percent. In the follow-up period of postprocedural 3 months to more than 12 months, an incremental trend of endothelialization over time was observed with the ratio of 85.8 ± 8.0, 89.6 ± 7.6, 92.2 ± 4.5, 94.3 ± 2.9 percent, respectively (p < 0.0001). Notably, patients without PDL exhibited a swifter advancement in endothelialization compared to those with PDL, irrespective of device size. The multivariable Cox regression model showed that PDL (HR = 2.113, 95%CI: 1.300-3.435, p = 0.003), DSP (HR = 1.717, 95%CI: 1.113-2.647, p = 0.014) were independent risk factors of delayed endothelialization.

CONCLUSION

CCTA holds promise as an effective means of quantitatively assessing device endothelialization. Endothelialization advanced gradually over time, with PDL potentially impeding device endothelialization.

CLINICAL RELEVANCE STATEMENT

A comprehensive understanding of the correlation between endothelialization ratio, time, and residual shunt can establish a more dependable foundation for determining the appropriate anticoagulation treatment following left atrial appendage closure.

KEY POINTS

Current recommendations for postleft atrial appendage occlusion anti-platelet and anticoagulation therapy are based on animal studies. Cardiac computed tomography angiography (CCTA) combined with the UNet neural network model enables the quantitative assessment of device endothelialization. This technique will allow for additional studies to better understand device endothelialization to optimize treatments in this population.

Lights and shadows on left atrial appendage occlusion: mind the gap in knowledge and think twice on long-term outcomes

Ischemic stroke prevention represents a crucial concern in health systems, being associated with high morbidity and mortality. Atrial fibrillation is associated with 15-20% of ischemic strokes, in the presence of thrombus in the left atrial appendage in 90% of patients with nonvalvular atrial fibrillation. Oral anticoagulation represents the standard of care. However, left atrial appendage occlusions have been developed for selected patients with nonvalvular atrial fibrillation. With regard to the latter, particularly, some important concerns have been raised on the selection of patients potentially amenable to the procedure, seemingly emphasizing a gap in knowledge, real-life clinical practice, and current management guidelines. In light of the recent evidence regarding the current indications for management of left atrial appendage in presence of nonvalvular atrial fibrillation, the purpose of this critical review is to highlight the blind spots of left atrial appendage occlusion indications, taking into account the evidence-based mid- to long-term outcomes. Apparently, many unsolved concerns and problems are still present, mainly including mid- and long-term device-related potential complications, the possibility of concurrent sources of embolization, ethical and economic issues. Furthermore, larger, well designed, long-term, multicentric, and more inclusive studies, as well as shared/integrated registries are needed, aiming at comparing direct oral anticoagulation with left atrial appendage occlusion in the long run.

Minimalistic approach to left atrial appendage occlusion guided by cardiac computed tomography angiography

OBJECTIVE

To assess the feasibility and safety of the minimalistic approach to left atrial appendage occlusion (LAAO) guided by cardiac computed tomography angiography (CCTA).

METHODS

Ninety consecutive patients who underwent LAAO, with or without CCTA-guided, were matched (1:2). Each step of the LAAO procedure in the computed tomography (CT) guidance group (CT group) was directed by preprocedural CT planning. In the control group, LAAO was performed using the standard method. All patients were followed up for 12 months, and device surveillance was conducted using CCTA.

RESULTS

A total of 90 patients were included in the analysis, with 30 patients in the CT group and 60 matched patients in the control group. All patients were successfully implanted with Watchman devices. The mean ages for the CT group and the control group were 70.0 ± 9.4 years and 68.4 ± 11.9 years (P = 0.52), respectively. The procedure duration (45.6 ± 10.7 min vs. 58.8 ± 13.0 min, P < 0.001) and hospital stay (7.5 ± 2.4 day vs. 9.6 ± 2.8 day, P = 0.001) in the CT group was significantly shorter compared to the control group. However, the total radiation dose was higher in the CT group compared to the control group (904.9 ± 348.0 mGy vs. 711.9 ± 211.2 mGy, P = 0.002). There were no significant differences in periprocedural pericardial effusion (3.3% vs. 6.3%, P = 0.8) between the two groups. The rate of postprocedural adverse events (13.3% vs. 18.3%, P = 0.55) were comparable between both groups at 12 months follow-up.

CONCLUSIONS

CCTA is capable of detailed LAAO procedure planning. Minimalistic LAAO with preprocedural CCTA planning was feasible and safe, with shortened procedure time and acceptable increased radiation and contras consumption. For patients with contraindications to general anesthesia and/or transesophageal echocardiography, this promising method may be an alternative to conventional LAAO.

Pattern of Endothelialization in Left Atrial Appendage Occluder by Optic Coherence Tomography: A Pilot Study

BACKGROUND

Implantation of the left atrial appendage occluder (LAAO) has been proven to prevent stroke effectively in patients with atrial fibrillation who cannot tolerate anticoagulants. Incomplete endothelization of LAAO may cause device-related thrombus, and currently no good image modality exists to clearly see LAAO endothelialization. We aimed to use coronary optic coherence tomography (OCT) to visualize LAAO endothelialization.

METHODS AND RESULTS

We enrolled 14 patients (72.8±9.4 years old) undergoing pulmonary vein isolation with a preexisting LAAO implanted more than 1 year ago (5 Watchman and 9 Amulet). After pulmonary vein isolation, we did OCT via steerable sheath and coronary guiding catheter to adjust OCT probe location and injected contrast medium to visualize the LAAO surface. In vitro testing was also performed to see the bare occluder. In vitro OCT showed the surface of the bare device as an interrupted granule pattern, which included the Watchman surface polytetrafluoroethylene membrane string, Amulet disc metal strut, and inner polytetrafluoroethylene membrane string. In the implanted Watchman, OCT showed endothelialization as a smooth surface layer with noninterrupted coarser granules. In the implanted Amulet, OCT showed endothelialization as thin (early) or thick (late) endothelialization layer covering struts with OCT shadows. Among patients with Watchman, 2 showed no, 2 early, and 1 complete endothelialization. Among patients with Amulet, 2 showed no, 3 early, and 4 late endothelialization.

CONCLUSIONS

We demonstrated the feasibility of OCT to visualize LAAO endothelization with high resolution. Further studies are needed to determine antithrombotic regimens if incomplete endothelization is detected. A new OCT catheter may be designed specifically for LAAO.

Is spontaneous echo contrast associated with device-related thrombus or embolic events after left atrial appendage occlusion? - Insights from the multicenter German LAARGE registry

BACKGROUND

Interventional left atrial appendage occlusion (LAAO) provides an alternative to oral anticoagulation (OAC) for prophylaxis of thromboembolic events (TEs) in nonvalvular atrial fibrillation patients, predominantly in those with high bleeding risk and contraindications for long-term OAC. Although spontaneous echo contrast (SEC) is a well-known risk factor for atrial thrombus formation, little is known about whether this means an increased risk of device-related thrombus (DRT) or TEs following LAAO.

METHODS

This substudy of the prospective, multicenter German LAARGE registry assessed two groups according to absence (SEC -) or presence of SEC (SEC +) in preprocedural cardiac imaging. Clinical and echocardiographic parameters were registered up to 1 year after LAAO.

RESULTS

Five hundred eighty-eight patients (SEC - 85.5 vs. SEC + 14.5%) were included. More SEC + patients were implanted for OAC non-compliance (11.8 vs. 4.6%, p = 0.008) and a higher proportion received only antiplatelet therapy without OAC at hospital discharge (96.5 vs. 86.0%, p = 0.007). The SEC + patients had larger LA diameters (50 (47; 54) vs. 47 (43; 51) mm, p < 0.001), wider LAA ostia (21 (19; 23) vs. 20 (17; 22) mm at 45°, p = 0.011), and lower left ventricular ejection fraction (50 (45; 60) vs. 60 (50; 60) %, p < 0.001) on admission. Procedural success was very high in both groups (98.1%, p = 1.00). Periprocedural major adverse cardiac and cerebrovascular events and other major complications were rare in both groups (3.8 vs. 4.7%, p = 0.76). At follow-up, DRT was only detected in the SEC - group (3.8 vs. 0%, p = 1.00). The rates of TEs (SEC - 1.2 vs. SEC + 0%, p = 1.00) after hospital discharge and 1-year mortality (SEC - 12.0 vs. SEC + 11.8%, p = 0.96) were not significantly different between the two groups.

CONCLUSIONS

Presence of SEC at baseline was not associated with an increased rate of DRT or TEs at 1-year follow-up after LAAO in LAARGE.

Left atrial appendage closure for stroke prevention in atrial fibrillation patients: A promise that came true

Anticoagulation therapy plays a crucial role in the management of atrial fibrillation (AF), considering the high morbidity and mortality of AF-related ischemic strokes. With the plausible hypothesis that left atrial appendage is the main source of thrombus in AF patients, left atrial appendage closure (LAAC) has been regarded as a potential substitute to oral anticoagulation in order to meet the unmet needs for stroke prevention, particularly in patients with high bleeding risk. Notable advancements in safety, efficacy, and device innovation have been made in recent years, albeit concerns still remain regarding the insufficient efficacy data, device-related complications, and the need for procedural optimization. We aim to review current knowledge about LAAC and provide potential future directions for the remaining key issues.

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

BACKGROUND

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

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

Persistent and Recurrent Device-Related Thrombus After Left Atrial Appendage Closure: Incidence, Predictors, and Outcomes

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.

Impact of Device Implant Depth After Left Atrial Appendage Occlusion

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Non-Pharmacological Stroke Prevention in Atrial Fibrillation

Atrial fibrillation (AF) is the most common arrhythmia worldwide. It is associated with increased mortality and morbidity, especially due to the increased risk of ischemic stroke and systemic embolism in these patients. For this reason, thromboembolism prevention is the cornerstone of managing AF, and oral anticoagulation is nowadays the first-line treatment. However, since most thrombi form in the left atrial appendage and anticoagulant therapy may have side effects and be contraindicated in some patients, surgical and percutaneous left atrial appendage occlusion (LAAO) have emerged as a non-pharmacological alternative. This review summarizes all existing evidence on surgical and percutaneous LAAO.

Enhanced Thromboresistance and Endothelialization of a Novel Fluoropolymer-Coated Left Atrial Appendage Closure Device

BACKGROUND

Device-related thrombus (DRT) after left atrial appendage closure (LAAC) procedures is a rare but potentially serious event. Thrombogenicity and delayed endothelialization play a role in the development of DRT. Fluorinated polymers are known to have thromboresistant properties that may favorably modulate the healing response to an LAAC device.

OBJECTIVES

The goal of this study was to compare the thrombogenicity and endothelial coverage (EC) after LAAC between the conventional uncoated WATCHMAN FLX (WM) and a novel fluoropolymer-coated WATCHMAN FLX (FP-WM).

METHODS

Canines were randomized for implantation with WM or FP-WM devices and given no postimplant antithrombotic/antiplatelet agents. The presence of DRT was monitored by using transesophageal echocardiography and verified histologically. The biochemical mechanisms associated with coating were assessed by using flow loop experiments to quantify albumin adsorption, platelet adhesion, and porcine implants to quantify EC and the expression of markers of endothelial maturation (ie, vascular endothelial-cadherin/p120-catenin).

RESULTS

Canines implanted with FP-WM exhibited significantly less DRT at 45 days than those implanted with WM (0% vs 50%; P < 0.05). In vitro experiments showed significantly greater albumin adsorption (52.8 [IQR: 41.0-58.3] mm2 vs 20.6 [IQR: 17.2-26.6] mm2; P = 0.03) and significantly less platelet adhesion (44.7% [IQR: 27.2%-60.2%] vs 60.9% [IQR: 39.9%-70.1%]; P < 0.01) on FP-WM. Porcine implants showed significantly greater EC by scanning electron microscopy (87.7% [IQR: 83.4%-92.3%] vs 68.2% [IQR: 47.6%-72.8%]; P = 0.03), and higher vascular endothelial-cadherin/p120-catenin expression after 3 months on FP-WM compared with WM.

CONCLUSIONS

The FP-WM device showed significantly less thrombus and reduced inflammation in a challenging canine model. Mechanistic studies indicated that the fluoropolymer-coated device binds more albumin, leading to reduced platelet binding, less inflammation, and greater EC.

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

Left atrial appendage occlusion

Prevention of stroke represents a goal of primary importance in health systems due to its associated morbidity and mortality. As several patient groups with increased stroke rates have been identified, multiple approaches have been developed and implemented: oral anticoagulation (OAC) for patients with atrial fibrillation, surgical and percutaneous revascularisation in patients with carotid disease, device closure for patients with patent foramen ovale, and now, left atrial appendage occlusion (LAAO) for selected patients with non-valvular atrial fibrillation (NVAF). The latter group of patients are the focus of this review which evaluates the pathophysiology, selection of patients, procedural performance, outcomes of treatment both during and post-procedure, adjunctive therapy, complications, and longer-term outcomes.

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

3-Year outcomes after left atrial appendage closure in patients with nonvalvular atrial fibrillation: cardiomyopathy related with increased death and stroke rate

INTRODUCTION

Left atrial appendage closure (LAAC) is a novel treatment for stroke prevention in high-risk patients with non-valvular atrial fibrillation (NVAF). However, the long-term outcomes after LAAC in Chinese NVAF patients are still lacking.

METHODS

This was a single-center, bidirectional, nonrandomized registered study. Patients who underwent LAAC implantation from May 2014 to April 2021 in a large Chinese center were enrolled. The primary endpoint was combined all-cause death and stroke.

RESULTS

From May 2014 to April 2021, a total of 673 NVAF patients were enrolled. The overall successful implantation rate was 97.62% (657 of 673). The rate of perioperative adverse events was 1.19% (8 of 673), including 3 cardiac tamponades, 2 ischemic strokes, one device-related thrombus (DRT) and 2 device dislocations. 604 (92.24%) patients completed the follow-up, the median follow-up period was 36.9 months (IQR 24.8-56.5 months). 16 stroke events occurred in 15 patients (one patient suffered from both hemorrhagic and ischemic strokes). 13 patients (2.15%) had ischemic stroke, and the fatal rate was 0.33% (2 of 604). 3 patients (0.15%) suffered from hemorrhagic stroke, and the fatal rate was 0.17% (1 of 604). The overall stroke rate was 0.74% per-year. The combined death and stroke rate was 1.93% per-year. In the multivariate Cox regression analysis, age ≥ 75 (hazard ratio 2.264, 95% CI 1.074-4.772, P = 0.032) and ventricular cardiomyopathy (hazard ratio 2.738, 95% CI 1.060-7.071, P = 0.037) were independent predictors of combined mortality and stroke.

CONCLUSION

The overall successful implantation rate of LAAC was 97.62% and the rate of perioperative adverse events was 1.19% in this study, and the stroke rate was 0.74% per year during the long-term follow-up. Age ≥ 75 years and ventricular cardiomyopathy were independent predictors of the primary endpoint. Trial registration This study was retrospectively registered.

Looking for optimal antithrombotic strategy after transcatheter left atrial appendage occlusion: a real-world comparison of different antiplatelet regimens

BACKGROUND

Transcatheter left atrial appendage occlusion (LAAO) has emerged as an effective procedure for the prevention of thromboembolic events in non-valvular atrial fibrillation (AF) patients with contraindications to oral anticoagulation. After the procedure, different antithrombotic regimens have been used, in order to prevent device-related thrombus and trying to minimize bleedings. The search for the optimal antithrombotic strategy is still ongoing. We sought to assess efficacy and safety of different antiplatelet therapy (APT) regimens.

METHODS

We enrolled non-randomized consecutive patients who underwent LAAO at the University Hospital of Parma between 2010 and 2021. Three study groups were identified according to post-procedural APT: long (>1, ≤12 months)-dual APT (DAPT), short (≤ 1 month)-DAPT, lifelong single APT (SAPT). The choice of the APT was left to multidisciplinary team evaluation. The incidence of the primary outcome, a composite of any ischemic or hemorrhagic event, was assessed at follow-up.

RESULTS

We enrolled a total of 130 patients. Technical success was achieved in 123 (94.6%) patients. After LAAO, 39 [31.7%] patients were discharged on short-DAPT, 35 [28.5%] on long-DAPT and 49 [39.8%] on SAPT. After a median follow-up of 32 months, short-DAPT group had a significantly lower occurrence of the primary outcome (3 [7.7%] vs. 7 [20.0%] in long-DAPT vs. 14 [28.6%] in SAPT, p = 0.049], mainly driven by a lower occurrence of the bleeding endpoint (0 vs. 4 [11.4%] in long-DAPT vs. 9 [18.4%] in SAPT, p = 0.020). Finally, comparison of the Kaplan-Meier curves showed that short-DAPT group had a higher primary endpoint-free survival [p = 0.015] compared to the other groups.

CONCLUSION

Post-procedural short-DAPT strategy was associated with better outcomes, mainly driven by reduction of major bleedings.

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

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

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

Aims

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

Methods

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

Results

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

Conclusion

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

Systematic review registration

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

Unexpected large device related thrombus at 12 months follow-up after left atrial appendage closure

An 89-year-old woman underwent left atrial appendage (LAA) closure (LAAC) in our hospital because of recurrent gastrointestinal bleedings. The first transesophageal echocardiography (TEE) follow-up at six weeks revealed a complete sealing of the LAA and no device related thrombus. In a TEE follow-up at one year after the LAA closure, a large device related thrombus (6 × 3 cm) was found. Treated with oral anticoagulation (apixaban) the thrombus showed a partial resolution one year later.

Left Atrial Appendage Occlusion: Current Advances and Remaining Challenges

The field of left atrial appendage occlusion is rapidly evolving. However, several issues remain including the limited randomized efficacy data, peri-device leak, device-related thrombus, and the ongoing refinement of procedural techniques. In this article, we provide a contemporary overview of left atrial appendage occlusion focusing on 4 key remaining challenges: efficacy data, peri-device leak, device-related thrombus, and procedural optimization.

Der interventionelle Vorhofohrverschluss: eine Alternative zur oralen Antikoagulation

Die orale Antikoagulation ist der Standard zur Prävention von Embolien bei Patienten mit Vorhofflimmern. Der interventionelle Vorhofohrverschluss ist eine Alternative zur oralen Antikoagulation bei Patienten mit Vorhofflimmern und Kontraindikationen oder Unverträglichkeiten einer oralen Antikoagulation, insbesondere bei klinisch relevanten Blutungen. Die Sicherheit des Verfahrens hat in den letzten Jahren erheblich zugenommen. Mehrere große randomisierte Studien vergleichen aktuell die Effektivität und Sicherheit der oralen Antikoagulation und des interventionellen Vorhofohrverschlusses.

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.

Left Atrial Appendage Occlusion: Current Stroke Prevention Strategies and a Shift Toward Data-Driven, Patient-Specific Approaches

The left atrial appendage (LAA) is a complex structure with unknown physiologic function protruding from the main body of the left atrium. In patients with atrial fibrillation, the left atrium does not contract effectively. Insufficient atrial and LAA contractility predisposes the LAA morphology to hemostasis and thrombus formation, leading to an increased risk of cardioembolic events. Oral anticoagulation therapies are the mainstay of stroke prevention options for patients; however, not all patients are candidates for long-term oral anticoagulation. Percutaneous occlusion devices are an attractive alternative to long-term anticoagulation therapy, although they are not without limitations, such as peri-implant leakage and device-related thrombosis. Although efforts have been made to reduce these risks, significant interpatient heterogeneity inevitably yields some degree of device-anatomy mismatch that is difficult to resolve using current devices and can ultimately lead to insufficient occlusion and poor patient outcomes. In this state-of-the-art review, we evaluated the anatomy of the LAA as well as the current pathophysiologic understanding and stroke prevention strategies used in the management of the risk of stroke associated with atrial fibrillation. We highlighted recent advances in computed tomography imaging, preprocedural planning, computational modeling, and novel additive manufacturing techniques, which represent the tools needed for a paradigm shift toward patient-centric LAA occlusion. Together, we envisage that these techniques will facilitate a pipeline from the imaging of patient anatomy to patient-specific computational and bench-top models that enable customized, data-driven approaches for LAA occlusion that are engineered specifically to meet each patient's unique needs.

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Device-related thrombus following left atrial appendage occlusion

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

Temporal changes and clinical significance of peridevice leak following left atrial appendage occlusion with Amplatzer devices

Background

The natural history of peridevice leak (PDL) following left atrial appendage occlusion (LAAO) is unknown. This study sought to investigate changes of PDL from 2 until 12 months after LAAO, using cardiac computed tomography (CT), and to assess the potential association between persistent PDL and clinical outcomes

Methods

Single‐center observational study of Amplatzer LAAO implants between 2010 and 2017 (n = 206). Patients with 2 and 12 months cardiac CT were included in the study (n = 153). Images were blindly analyzed. PDL was characterized by frequency and size at the device disc, lobe, and left atrial appendage contrast patency. Patients were followed for the composite outcome of ischemic stroke, transient ischemic attack, systemic embolism, or all‐cause death. Median follow up from LAAO was 3.1 (2.3–4.3) years.

Results

Contrast patency was present in 101 (66%) and 72 (47%) (p < 0.001) at 2 and 12 months, respectively. PDL was identified at the disc in 103 (67%) patients at 2 months versus 93 (61%) at 12 months (p = 0.08), and at the lobe in 29 (19%) at both time points. PDL area at the disc did not change significantly over time, ∆ area: −8.95 mm (95% confidence interval [CI]: −18.9; 1.01) p = 0.08. Permanent atrial fibrillation was independently associated with persistent PDL. Persistent versus no PDL was associated with a 62% worse clinical outcome, however not statistically significant, hazard ratio (HR): 1.62 (95% CI: 0.9–2.93), p = 0.11.

Conclusion

Persistent PDL was frequently observed following LAAO with Amplatzer devices. The PDL frequency and size appeared unchanged between 2 and 12 months. Persistent PDL was not significantly associated with worse clinical outcomes, yet this needs further delineation in future studies.

Transient Ischemic Attack Secondary to Device-Related Thrombus After Left Atrial Appendage Closure

The patient is an 84-year-old female with a significant past medical history of traumatic subarachnoid hemorrhage, bleeding peptic ulcer disease, permanent atrial fibrillation status post percutaneous left atrial appendage closure (LAAC) initially admitted to the hospital secondary to expressive aphasia. The patient was found to have a transient ischemic attack (TIA). A transesophageal echocardiogram (TEE) showed a thrombus on the watchman device (WD). The patient was treated with unfractionated heparin infusion and later transitioned to apixaban without any further TIA or stroke over 30 days period. Device-related thrombosis (DRT) with systemic thromboembolism occurred almost after 480 days of putting the WD which is very rare. 

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

AIMS

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

METHODS AND RESULTS

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

CONCLUSIONS

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

2021 Focused update of the 2017 consensus guidelines of the Asia Pacific Heart Rhythm Society (APHRS) on stroke prevention in atrial fibrillation

The consensus of the Asia Pacific Heart Rhythm Society (APHRS) on stroke prevention in atrial fibrillation (AF) has been published in 2017 which provided useful clinical guidance for cardiologists, neurologists, geriatricians, and general practitioners in Asia-Pacific region. In these years, many important new data regarding stroke prevention in AF were reported. The Practice Guidelines subcommittee members comprehensively reviewed updated information on stroke prevention in AF, and summarized them in this 2021 focused update of the 2017 consensus guidelines of the APHRS on stroke prevention in AF. We highlighted and focused on several issues, including the importance of AF Better Care (ABC) pathway, the advantages of non-vitamin K antagonist oral anticoagulants (NOACs) for Asians, the considerations of use of NOACs for Asian patients with AF with single 1 stroke risk factor beyond gender, the role of lifestyle factors on stroke risk, the use of oral anticoagulants during the "coronavirus disease 2019" (COVID-19) pandemic, etc. We fully realize that there are gaps, unaddressed questions, and many areas of uncertainty and debate in the current knowledge of AF, and the physician's decision remains the most important factor in the management of AF.

Left atrial appendage closure - Current status and future directions

Percutaneous left atrial appendage closure (LAAC) has become an important non-pharmacological intervention for stroke prevention in patients with non-valvular atrial fibrillation (AF). LAAC aims to reduce the risk of thromboembolism without increasing the risk of bleeding, a crucial strategy for patients at high risk for bleeding. Over the last few decades, the safety and long-term efficacy of the procedure in specific populations have grown, and more patients are being treated with these devices. Current and future studies focus on expanding the target population as well as the iteration of current technology. This article reviews recent, present, and future LAAC studies on the two most common devices, the Watchman device (Boston Scientific Corporation) and the Amplatzer cardiac plug (ACP) (St. Jude Medical, Minneapolis, MN), and their subsequent next generations, the Watchman FLX, and the Amulet, respectively.

2021 Focused Update Consensus Guidelines of the Asia Pacific Heart Rhythm Society on Stroke Prevention in Atrial Fibrillation: Executive Summary

The consensus of the Asia Pacific Heart Rhythm Society (APHRS) on stroke prevention in atrial fibrillation (AF) has been published in 2017 which provided useful clinical guidance for cardiologists, neurologists, geriatricians, and general practitioners in the Asia-Pacific region. In these years, many important new data regarding stroke prevention in AF were reported. The practice guidelines subcommittee members comprehensively reviewed updated information on stroke prevention in AF, and summarized them in this 2021 focused update of the 2017 consensus guidelines of the APHRS on stroke prevention in AF. We highlighted and focused on several issues, including the importance of the AF Better Care pathway, the advantages of non-vitamin K antagonist oral anticoagulants (NOACs) for Asians, the considerations of use of NOACs for Asian AF patients with single one stroke risk factor beyond gender, the role of lifestyle factors on stroke risk, the use of oral anticoagulants during the “coronavirus disease 2019” pandemic, etc. We fully realize that there are gaps, unaddressed questions, and many areas of uncertainty and debate in the current knowledge of AF, and the physician's decision remains the most important factor in the management of AF.