Incidence, Characteristics, and Clinical Course of Device-Related Thrombus After Watchman Left Atrial Appendage Occlusion Device Implantation in Atrial Fibrillation Patients

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

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

Association between preprocedural thromboembolic and bleeding events under oral anticoagulation therapy and mid-term outcomes after percutaneous left atrial appendage closure

Currently, no consensus has been established on the most effective antithrombotic therapy to prevent thromboembolic and bleeding events in patients undergoing percutaneous left atrial appendage closure (LAAC) with preprocedural thromboembolic or bleeding events under oral anticoagulation (OAC) therapy. We retrospectively investigated the incidence of device-related thrombosis (DRT), thromboembolic events, and bleeding events in patients who underwent LAAC from September 2019 to October 2022. After categorizing patients into three groups based on preprocedural thromboembolic or bleeding events under OAC therapy, we compared the incidence of DRT and prognosis according to the postprocedural antithrombotic therapy. In patients who received the conventional antithrombotic therapy (OAC with and without single antiplatelet therapy for 45 days after LAAC and dual-antiplatelet therapy from 45 days to 6 months followed by single antiplatelet therapy), preprocedural thromboembolic events despite OAC were independently associated with DRT or postprocedural thromboembolic events at the 3 year follow-up (hazard ratio [HR] 4.55; 95% confidence interval [CI] 1.32-15.6; P = 0.016), whereas preprocedural bleeding events were independently associated with postprocedural bleeding events (HR 8.01, 95% CI 1.45-58.3; P = 0.036). Continuation of OAC for 12 months among patients who developed preprocedural thromboembolic events during OAC significantly decreased the incidence of DRT or postoperative thromboembolic events (P = 0.002) with no increase in the bleeding events (P = 0.522). Preprocedural thromboembolic and bleeding events can predict adverse events after LAAC with the conventional antiplatelet-based antithrombotic therapy. Patients who develop thromboembolic events under continuous OAC may benefit from continuous OAC for 1 year after LAAC.

Predictors of Device-Related Thrombus After Left Atrial Appendage Occlusion: TED-F2 Score

Background

Left atrial appendage (LAA) occlusion (LAAO) is performed to prevent LAA thrombus in patients with atrial fibrillation (AF). The risk of device-related thrombus (DRT) on the atrial side of the LAAO device is approximately 4%. Identifying patients at high risk of DRT would enable closer surveillance and more-aggressive anticoagulation to prevent post-LAAO DRT-related stroke.

Methods

From the LAAO registry at The University of Kansas Medical Center, we identified patients who developed DRT. We chose 3 unmatched controls per DRT case from LAAO recipients without DRT. Predictor variables were obtained from transesophageal echocardiogram reports and/or images, transthoracic echocardiogram reports, and chart review. Implant depth was measured from the limbus of the left atrial ridge to the centre of the atrial aspect of the LAAO device, on a 45° transesophageal echocardiogram view.

Results

We identified 26 patients with DRT (aged 77.7 ± 9.7 years; 34.6% female) and selected 78 unmatched controls without DRT. Univariate predictors of DRT, comprising a novel TED-F2 score, included history of venous Thromboembolism (23.1% vs 5.1%, P = 0.01), an LAA Emptying velocity ≤ 20 cm/s (45.8% vs 18.9%, P = 0.01), an implant Depth > 2 cm (34.6% vs 12.8%, P = 0.02), and presence of AF rhythm at time of device implantation (50.0 % vs 11.5%, P = 0.0001). A TED-F2 score of ≥ 3 was very strongly associated with DRT-odds ratio 12.5 (95% confidence interval, 3.8-41.1, P < 0.0001).

Conclusions

We propose a novel risk score to predict development of DRT after LAAO, comprising history of venous Thromboembolism, LAA Emptying velocity ≤ 20 cm/s, implant Depth > 2 cm (1 point each), and an AF rhythm at implantation (2 points). A TED-F2 risk score of ≥ 3 identified patients who are at greatly elevated risk of developing DRT.

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.

Incidental Complication From a Left Atrial Appendage Device

This case report describes a diagnosis of extracardiac mural thrombus and pulmonary emboli resulting from a left atrial appendage device in a patient with atrial fibrillation.

Clinical incidence and relevance of incomplete endothelialization in atrial fibrillation patients with Left Atrial Appendage Closure

BACKGROUND

The objective of this study is to investigate the incidence, potential risk factors, and clinical outcomes of incomplete device endothelialization (IDE) in atrial fibrillation (AF) patients undergoing Watchman left atrial appendage closure (LAAC).

METHODS

In this study, 68 AF patients who underwent successful implantation of the Watchman device without peri-device leak (PDL) during follow-up were included. The endothelialization status was assessed using Transesophageal echocardiography (TEE) and LAA computed tomography angiography (CTA) at 6 weeks and 6 months post-implantation. Adverse cerebro-cardiac events were documented at one-year follow-up. Baseline characteristics, including age, device sizes, and clinical indicators, were analyzed as potential predictors for IDE.

RESULTS

IDE was observed in 70.6% and 67.6% of patients at 6 weeks and 6 months after implantation, respectively. Higher levels of high-density lipoprotein cholesterol (HDL-C) [odds ratio (OR): 15.109, 95% confidence interval (CI): 1.637-139.478, p = 0.017 and OR: 11.015, 95% CI: 1.365-88.896, p = 0.024] and lower aspartate aminotransferase (AST) (OR 0.924, 95% CI: 0.865-0.986, p = 0.017 and OR: 0.930, 95% CI: 0.874-0.990, p = 0.023) at baseline were found to be significantly associated with IDE at 6 weeks and 6 months, respectively, although no significant difference in adverse cerebro-cardiac events was noted between incomplete and complete DE groups during 1-year follow-up CONCLUSIONS: IDE is found to be a prevalent occurrence in humans following LAAC. Elevated HDL-C and reduced AST levels are shown to be linked to an increased risk of IDE after LAAC.

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.

"The Failing Watchman": Recurrent Left Atrial Appendage Occlusion Device (LAAOD) Thrombus After Successful Initial Implantation

A 79-year-old female with chronic atrial fibrillation was being treated with dabigatran (Pradaxa). Pradaxa was discontinued after a significant bleeding episode. A WATCHMAN device was successfully implanted and Pradaxa was started. A transesophageal echocardiogram (TEE) 49 days later showed a 3.6×2.2 cm clot overlying the device. Pradaxa was switched to Coumadin. Subsequent TEEs showed the complete resolution of the thrombus after five months on Coumadin. Coumadin was discontinued. Six months later, TEE showed a large mobile thrombus attached to the left atrial appendage occlusion device (LAAOD). The patient's hypercoagulable workup was negative. Due to recurrent thrombotic events, she was started on apixaban (Eliquis) due to a prior history of bleeding on Coumadin. She is currently on Eliquis with no further episodes of bleeding or device thrombus.

Initial results of transcatheter modification of left atrial appendage by obliteration with device in patients with nonvalvular atrial fibrillation: Real-world data from the TERMINATOR registry

BACKGROUND

Percutaneous left atrial appendage closure (LAAC) has increased for those who need alternative to long-term anticoagulation with non-valvular atrial fibrillation (NVAF).

METHODS AND RESULTS

From September 2019, after initiating WATCHMAN (Boston Scientific, Maple Grove, MN, USA) device implantation, we established Transcatheter Modification of Left Atrial Appendage by Obliteration with Device in Patients from the NVAF (TERMINATOR) registry. Utilizing 729 patients' data until January 2022, we analyzed percutaneous LAAC data regarding this real-world multicenter prospective registry. A total of 729 patients were enrolled. Average age was 74.9 years and 28.5 % were female. Paroxysmal AF was 37.9 % with average CHADS2 3.2, CHA2DS2-VASc 4.7, and HAS-BLED score of 3.4. WATCHMAN implantation was successful in 99.0 %. All-cause deaths were 3.2 %, and 1.2 % cardiovascular or unexplained deaths occurred during follow-up [median 222, interquartile range (IQR: 93-464) days]. Stroke occurred in 2.2 %, and the composite endpoint which included cardiovascular or unexplained death, stroke, and systemic embolism were counted as 3.4 % [median 221, (IQR: 93-464) days]. Major bleeding defined as BARC type 3 or 5 was seen in 3.7 %, and there was 8.6 % of all bleeding events in total [median 219, (IQR: 93-464) days].

CONCLUSIONS

These preliminary data demonstrated percutaneous LAAC with WATCHMAN device might have a potential to reduce stroke and bleeding events for patients with NVAF. Further investigation is mandatory to confirm the long-term results of this strategy using this transcatheter local therapy instead of life-long systemic anticoagulation.

Outcomes and Readmissions after Left Atrial Appendage Occlusion in Octogenarians: A Contemporary Analysis

INTRODUCTION AND OBJECTIVES

The outcomes of left atrial appendage occlusion (LAAO) with the Watchman device in octogenarians are unknown as this population was underrepresented in major clinical trials. This study aims at examining the causes and outcomes of readmission after LAAO.

DESIGN

A retrospective cohort study based on the National Readmission Database in the United States.

SETTINGS AND PARTICIPANT

Patients aged ≥80 years, admitted between January 2016 and December 2018, with the primary diagnosis of atrial fibrillation or flutter or who had LAAO were included in the study. Patients who died during index admission were excluded.

METHODS

We used the National Readmission Database and International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes to identify study participants. Data analysis was performed through Stata, version 17. Univariate and multivariate aggression analysis was used to adjust for confounders using Student t tests and χ2 tests.

RESULTS

We identified 491,329 patients on anticoagulation (AC) and 2030 patients who underwent LAA closure. Neither group differed regarding hypertension, previous myocardial infarction, or valvular heart disease. All-cause readmissions were lower in the LAAO group at 45 days (adjusted P < .01). All-cause readmissions at 45 and 90 days were similar in both groups. There was an increase in gastrointestinal bleeding (GIB) readmissions in the LAAO at 45 (P < .01), 90 (P < .01), and 180 (P < .01) days. There was no difference in GIB readmission between the 2 groups. There was no also difference in stroke or intracranial hemorrhage rates between the 2 groups throughout the follow-up period.

CONCLUSION AND IMPLICATIONS

In octogenarians who received LAAO, the rate of GIB increased during the first 6 months after the procedure; however, it was not different from that of AC after that. Special attention should be given to the antithrombotic regimens after LAAO to avoid bleeding in this vulnerable patient population.

2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation" provides recommendations to guide clinicians in the treatment of patients with atrial fibrillation.

METHODS

A comprehensive literature search was conducted from May 12, 2022, to November 3, 2022, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through November 2022, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Atrial fibrillation is the most sustained common arrhythmia, and its incidence and prevalence are increasing in the United States and globally. Recommendations from the "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" and the "2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing atrial fibrillation and thromboembolic risk assessment, anticoagulation, left atrial appendage occlusion, atrial fibrillation catheter or surgical ablation, and risk factor modification and atrial fibrillation prevention have been developed.

Left atrial appendage closure: the journey today and tomorrow

PURPOSE OF REVIEW

This review aims to discuss the rationale behind the development of percutaneous LAAC devices as a treatment option for atrial fibrillation patients ineligible for long-term anticoagulation. The evolution of LAAC, from early experiences and challenges to risk mitigation and improved devices and techniques, will be examined. Furthermore, the review will explore our current understanding of the potential and limitations of LAAC in stroke prevention.

RECENT FINDINGS

Multiple trials confirm LAAC device safety and efficacy for stroke prevention, but peri-device leak and thrombus remain concerns postimplantation. Even small leaks pose increased stroke risk. While guidelines suggest short-term anticoagulation postimplant; real-world data show equivalent efficacy with dual antiplatelet regimen.

SUMMARY

LAAC device design has evolved and now serve as a viable option for stroke prevention in high-risk atrial fibrillation patients, offering protection in the absence of anticoagulation.

Association between rates of ischemic stroke and all-cause mortality with the Watchman device compared to warfarin and direct oral anticoagulants in patients with atrial fibrillation

Introduction

The Watchman device is approved in the US, but little is known about Watchman's ischemic stroke reduction compared to the newer direct oral anticoagulants (DOACs). This study explored the differences in ischemic stroke reduction between the Watchman device, warfarin, and DOAC medication.

Methods

Three patient cohorts, each containing 10,969 patients, were created using TriNetX. The primary and secondary endpoints were the ischemic stroke risk and all-cause mortality risk at 1 and 5 years.

Results

At 1 year, the Watchman device's relative risk of ischemic stroke was 0.86 against warfarin but 1.27 against DOACs (P < 0.0001). The relative risk of ischemic stroke between the Watchman and DOACs was higher at 1 and 5 years (1.27 and 1.30, P < 0.0001). The relative risk of all-cause mortality at 1 and 5 years was 0.49 and 0.72 for the Watchman device compared to warfarin (P < 0.0001) and 0.66 and 0.92 between the Watchman and DOACs (P < 0.0001 and 0.01).

Conclusion

While DOACs were associated with lower ischemic stroke rates, treatment with the Watchman device was associated with lower all-cause mortality. Patients placed on the Watchman device due to DOAC contraindications may benefit from its lower all-cause mortality risk.

Echocardiography in Percutaneous Left Atrial Appendage Occlusion and Related Complications

Atrial fibrillation (AF) is a devastating disease with a large global prevalence. The left atrial appendage (LAA) is a major source of thrombi in patients with AF. Echocardiography plays an important role in identifying LAA thrombi and has become an invaluable imaging tool in planning for LAA occlusion (LAAO) in patients intolerant to anticoagulation. This review article will discuss the role of echocardiography in selecting patients for LAAO, intraprocedural monitoring, and identifying procedure-related complications.

Device-Associated Thrombus with Watchman FLX Left Atrial Appendage Closure Device: A Report of Two Cases

•

Individual cases of Watchman FLX DAT are scare in literature.

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The Watchman FLX has shown lower rates of DAT than the Watchman 2.0.

•

Thrombus formation is still possible in rare instances with the Watchman FLX.

Sex Differences in Periprocedural and Long-Term Outcomes Following Transcatheter Left Atrial Appendage Occlusion: A Systematic Review and Meta-Analysis

BACKGROUND

Atrial fibrillation (AF) is among the most common arrhythmias associated with an increased risk of cardioembolic phenomena, including stroke. Percutaneous left atrial appendage occlusion (LAAO) has proven beneficial in reducing stroke and mortality in patients with atrial fibrillation who have contraindications to anticoagulation. However, the sex differences in outcomes following LAAO have not been studied systematically.

METHODS

Electronic databases PUBMED, Embase, and Web of Science were systematically searched until March 2022 for studies evaluating patient outcomes following LAAO for AF. The primary outcomes of interest were the risks of periprocedural stroke, major bleeding, pericardial complications, and all-cause mortality. Secondary outcomes included stroke risks, major bleeding, device-related thrombus, cardiovascular and all-cause mortality on long-term follow-up. A random-effects model meta-analysis was conducted, and heterogeneity was assessed using the I-squared test.

RESULTS

Sixteen studies were included in the final analysis encompassing 111,775 patients, out of which 45,441 (40.7 %) were women. Women had a significantly higher risk of peri-procedural complications including all-cause mortality [relative risk (RR), 95 % confidence intervals (CI); RR 1.94, 95 % CI 1.40-2.69], stroke [RR 1.85, 95 % CI 1.29-2.67], major bleeding [RR 1.63, 95 % CI 1.08-2.44], and pericardial events [RR 1.80, 95 % CI 1.58-2.05]. However, there were no statistically significant differences between sexes in terms of risk of stroke, major bleeding, device-related thrombus, cardiovascular and all-cause mortality on long-term follow-up.

CONCLUSION

Among patients undergoing LAAO implantation, women were at higher risk of periprocedural complications than men. This risk was not significant on long-term follow-up.

Comparison of Adverse Events between Isolated Left Atrial Appendage Closure and Combined Catheter Ablation

(1) Background: This study aimed to investigate the effect of an additional catheter ablation (CA) procedure on the risk of post-procedure adverse events during CA combined with left atrial appendage closure (LAAC). (2) Methods: From July 2017 to February 2022, data from 361 patients with atrial fibrillation who underwent LAAC at our center were analyzed retrospectively. The adverse events were compared between CA + LAAC and LAAC-only groups. (3) Results: The incidence of device-related thrombus (DRT) and embolic events was significantly lower in the CA + LAAC group than in the LAAC-only group (p = 0.01 and 0.04, respectively). A logistic regression analysis revealed that the combined procedure served as a protective factor for DRT (OR = 0.09; 95% confidence interval: 0.01-0.89; p = 0.04). Based on a Cox regression analysis, the risk of embolism marginally increased in patients aged ≥65 years (HR = 7.49, 95% CI: 0.85-66.22 p = 0.07), whereas the combined procedure was found to be a protective factor (HR = 0.25, 95% CI: 0.07-0.87 p = 0.03). Further subgroup and interaction analyses revealed similar results. (4) Conclusions: The combined procedure may be associated with a lower rate of post-procedure DRT and embolization without a higher occurrence of other adverse events after LAAC. A risk-score-based prediction model was conducted, showing a good prediction performance.

Utility of transesophageal echocardiogram surveillance after watchman device placement

BACKGROUND

In atrial fibrillation patients undergoing left atrial appendage occlusion with a Watchman device, surveillance imaging with a transesophageal echocardiogram (TEE) is typically performed at 45 days and 1 year to evaluate for device-related thrombus (DRT) and peri-device leak (PDL) before the cessation of oral anticoagulation. The incidence of these complications is relatively low, and the ideal timing and duration of surveillance is unknown. We sought to evaluate the incidence of DRT and PDL after Watchman placement at 45 days and 1 year to determine the necessity of surveillance TEEs.

METHODS

We retrospectively analyzed 361 patients who received a Watchman device between January 2016 and January 2020. Baseline clinical and echocardiographic data, post-procedure antithrombotic therapy, and surveillance echocardiographic data were collected from the NCDR LAAO Registry. Nested backward variable elimination regression was performed to derive independent predictors of the composite outcome of DRT and PDL.

RESULTS

A total of 286 patients who had post-procedure TEEs were included in the analysis. At 45 days, 9 patients had DRT (3.2%) and 44 patients had PDL (15.0%). At 1 year, 5 patients had DRT (5.6%) and 8 patients had PDL (8.9%). All DRT at 45 days was treated with continued anticoagulation while no change in protocol occurred with PDL. All DRT at 1 year occurred in new patients without prior thrombus. A history of prior transient ischemic attack (TIA) and thromboembolism was significantly associated with DRT or PDL at 1 year.

CONCLUSIONS

We identified several patients with device-related complications at 45 days and 1 year despite appropriate device sizing and adequate use of antithrombotic therapy. The incidence of DRT increased from 45 days to 1 year and occurred in patients without prior thrombus. These findings highlight the importance of surveillance imaging and suggest the potential need for extended surveillance in select patients.

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.

Stroke prevention of thoracoscopic left atrial appendage clipping in patients with non-valvular atrial fibrillation at high risk of stroke and bleeding: study protocol for a non-randomised controlled clinical trial

INTRODUCTION

Non-valvular atrial fibrillation (NVAF) is a high-risk factor for ischaemic stroke. The 2016 European Society of Cardiology Atrial Fibrillation Management guidelines recommend oral anticoagulants (OACs) to prevent stroke in men with CHA2DS2-VASc scores ≥2 and women ≥3. However, in patients with a high risk of stroke and a high risk of bleeding (HAS-BLED (Hypertension, Abnormal renal/liver function, Stroke, Bleeding history or predisposition, Labile international normalized ratio, Elderly (> 65 years), Drugs/alcohol concomitantly) score≥3), OAC had a higher risk of bleeding. Left atrial appendage closure (LAAC) is non-inferior to OAC as a means of preventing stroke in several studies. As a minimally invasive intervention to prevent stroke, transthoracic LAAC (TS-LAAC) has a high successful closure rate, but there is a lack of literature reports directly comparing it with OAC. Our research compares TS-LAAC with novel oral anticoagulants (NOACs) and provides an appropriate programme for stroke prevention in a specific population.

METHODS AND ANALYSIS

This is a non-randomised controlled trial study protocol, and we will conduct this study from April 2022 to April 2025. The study included 186 patients with confirmed NVAF, 93 of whom completed thoracoscopic LAAC, and the control group treated with NOACs. The primary outcome was the incidence of stroke and systemic embolism, as well as the composite endpoint events (stroke, systemic embolism, myocardial infarction, bleeding, cardiovascular death, etc). Secondary outcomes were ischaemic stroke, haemorrhagic stroke, any bleeding events, death from cardiovascular causes, death from all causes, residual root rate in the surgery group, device-related thrombosis in the surgery group, changes in blood pressure, cardiac chamber size changes, etc. Each subject completed at least 1 year of follow-up.

ETHICS AND DISSEMINATION

The study has been approved by the Medical Ethics Committee of Beijing Tiantan Hospital, Capital Medical University, China (approval number: KY2022-013-02). The results from this study will be disseminated through manuscript publications and national/international conferences.

TRIAL REGISTRATION NUMBER

ChiCTR2200058109.

Evidence and Challenges in Left Atrial Appendage Management

This review aimed to discuss the anatomical properties of the left atrial appendage (LAA), its relationship with atrial fibrillation (AF), effectiveness of LAA occlusion (LAAO), techniques, and new devices used to perform this procedure. An electronic search was performed to identify studies, in the English language, on LAA management. Searches were performed on PubMed Central, Scopus, and Medline from the dates of database inception to February 2020. For the assessed papers, data were extracted from the reviewed text, tables, and figures, by two independent authors. Anticoagulant therapy for patients with AF has proven beneficial and is highly recommended, but it is challenging for many patients to maintain optimal treatment. Surgery is the most cost-effective option; surgical methods include simple LAA resection, thoracoscopic surgery, and catheter treatment. Each procedure has its advantages and disadvantages, and many prospective studies have been conducted to evaluate various treatment methods. In managing the LAA, dissection of the LAA, such as changes in its shape and size due to remodeling during AF, changes in autonomic nerve function, and thrombosis, must be understood anatomically and physiologically. We believe that early treatment intervention for the LAA should be considered particularly in cases of recurrent AF.

Conclusion: SLET under artificial pneumothorax is feasible and safe in minimally invasive McKeown esophagectomy.

Closure Device-Related Thrombosis After Anticoagulation With Dabigatran in Patients Undergoing Percutaneous Left Atrial Appendage Closure: Case Reports and Literature Review

Percutaneous left atrial appendage closure (LAAC) is an effective and safe operation strategy for stroke prevention in patients who are diagnosed with atrial fibrillation (AF) but cannot tolerate long term anticoagulation medication. We presented four rare cases of thrombosis formation on the occluder device. After the LAAC operation was successfully performed on patients, they followed a course of anticoagulation with dabigatran (110 mg b.i.d.), and device-related thrombosis (DRT) occurred as indicated by a transesophageal echocardiogram (TEE) during the follow-up period. Regressions were achieved after replacing dabigatran with rivaroxaban or warfarin for more than 1 month. No thrombosis or bleeding-related complications occurred in subsequent follow-ups.

Who Watches the "Watchman" and How Often?

Atrial fibrillation (AF) is a common cardiac arrhythmia that is encountered during the hospitalization. Sometimes, many patients cannot be anticoagulated to prevent AF-related cardiovascular accidents because of the risk of bleeding. In these cases, we recommend putting left atrial appendage (LAA) to prevent thrombus formation in the left atrium due to AF. There is no clear time frame of how long we need to follow up with echocardiogram to monitor device-related blood clot formation and continue anticoagulation therapy if there is recurrent thrombus formation after LAA placement. We would like to present a case with AF in which the patient had epistaxis, which required to hold anticoagulation and arterial embolization. The patient agreed to the placement of the Watchman device and subsequently it was complicated by device-related thrombosis (DRT). The patient required prolonged anticoagulation treatment and follow-up echocardiogram to prevent DRT in the future.

Clinical Outcomes following Left Atrial Appendage Occlusion: A Single-Center Experience

INTRODUCTION

Percutaneous left atrial appendage closure is an established alternative to anticoagulation therapy for stroke prophylaxis among patients with nonvalvular atrial fibrillation. There are currently no guidelines on the choice of antithrombotic therapy following placement of the Watchman® device, the optimal time to discontinue anticoagulation or the duration of follow-up imaging after device deployment. Our main objective was to evaluate clinical outcomes among these patients.

METHODS

We conducted a retrospective review of patients who received a Watchman® device at Mayo Clinic sites between January 2010 and December 2018. We constructed Cox-proportional hazard models to evaluate the effect of specific variables on clinical outcomes.

RESULTS

231 patients were identified (33% female), median age was 77 years, CHA2DS2-VASc score was 5 and HASBLED score was 4. We found no difference in clinically significant bleeding based on initial antithrombotic choice. However, patients with prior gastrointestinal bleeding were more likely to have a bleeding event in the first 6 weeks following Watchman® implantation (HR 9.40, 95% CI 2.15-41.09). Device sizes of 24-27 mm were significantly associated with a decreased risk of thromboembolic events (HR 0.15, 95% CI 0.04-0.55) compared to 21-mm devices. Peridevice leak (PDL) sizes appeared to either remain the same or increase on follow-up imaging.

DISCUSSION/CONCLUSIONS

This observational study showed no statistically significant difference in bleeding risk related to initial antithrombotic choice. Smaller device sizes were associated with thromboembolic events, and longitudinal PDL assessment using transesophageal echocardiography showed these frequently do not decrease in size. Larger studies are needed.

Follow-up imaging after left atrial appendage closure

BACKGROUND

Because device-related thrombus (DRT) portends a poor prognosis after left atrial appendage closure with the Watchman device, surveillance transesophageal echocardiography (TEE) is recommended at 45 days and 1 year. However, oral anticoagulants are just discontinued at 45 days, rendering this early TEE unlikely to detect DRT. Indeed, DRT is most likely to occur after instituting aspirin monotherapy.

OBJECTIVE

The purpose of this study was to evaluate the alternative strategy of first TEE imaging (or computed tomography) at 4 months post-Watchman implantation.

METHODS

After Food and Drug Administration approval, consecutive patients undergoing Watchman implantation at 2 centers received TEE or CT at 4 months and 1 year, along with a truncated drug regimen: 6 weeks of an oral anticoagulant (or clopidogrel in a subset) plus aspirin, then 6 weeks of dual antiplatelet therapy, and finally aspirin monotherapy.

RESULTS

Of the 530-patient cohort (mean age 78.7±7.9 years; 65.5% (n = 347) male; CHA₂DS₂-VASc score 4.5±1.4), 465 patients (87.7%) received 4-month imaging: 83.0% (440 of 530) TEE and 4.7% (25 of 530) computed tomography. Over a median follow-up of 12 months, 16 ischemic strokes (ISs), 8 transient ischemic attacks, and 1 systemic embolization occurred. Importantly, no IS occurred between 45 days and 4 months; the sole transient ischemic attack in this period (at ∼2 months) occurred 1 week after transcatheter aortic valve replacement. DRT was detected in 2.4% (11 of 465) at 4 months and 0.9% (2 of 214) at 1 year. No IS, but 1 leg embolization, was observed after DRT detection.

CONCLUSION

Delaying the first imaging post-Watchman implantation to 4 months was associated with no IS between 45 days and 4 months, the "vulnerable" period of this follow-up strategy.

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.

Initial anticoagulation experience with standard-dose rivaroxaban after Watchman left atrial appendage occlusion

Background

Warfarin is now recommended as the standard anti-thrombotic regimen to allow complete endothelialization over the Watchman device post percutaneous left atrial appendage occlusion (LAAO). However, the need for frequent monitoring, narrow therapeutic range, dietary restrictions and multiple drug interactions associated with warfarin have contributed to increasing uptake of non-vitamin K oral anticoagulants (NOACs) worldwide. At present, the feasibility and safety of NOACs instead of warfarin post-LAAO is lacking.

Methods

Patients who underwent successful Watchman device implantation between October 1, 2016 and September 30, 2017 were enrolled in a retrospective database. And only patients who received rivaroxaban in the periprocedural period were included in this study. Transesophageal echocardiography (TEE) follow-up was scheduled at 6 weeks, at 6 months, and at 12 months post-implantation to detect device-related thrombosis (DRT) or peri-device leak. Meanwhile, thromboembolic and bleeding events were also evaluated at the time of follow-up.

Results

Totally, 57 Watchman devices were successfully implanted and 10 patients who were allocated to rivaroxaban at the dosage of 20 mg once daily were included. During the follow-up, none of the patients using rivaroxaban experienced DRT, peri-device leak, thromboembolic complications and major bleeding events, except for 2 patients who suffered minor bleeding during the 6 weeks follow-up.

Conclusions

This study suggests that a short course of standard-dose rivaroxaban following Watchman LAAO is associated with low incidence of thrombotic complications and bleeding events, and might be a feasible alternative regimen in Chinese. Further randomized trials and large sample of real-world studies are needed to validate our finding.

The History of the Left Atrial Appendage Occlusion

Atrial fibrillation (AF) has been a source of fascination for more than 100 years. Most early investigations centered on the mechanisms of the arrhythmia (reentry versus automaticity; site of origin; approaches to treatment or prevention; and the clinical consequences), specifically tachycardia-induced cardiomyopathy and the potential for lethal events in special circumstances (eg, preexcitation syndromes). The current increased interest in AF has been heightened by increasing information on the clinical volume and number of patients affected. Recent data identify a current prevalence rate of 6 million patients in the United States, which is predicted to become 12 million by 2030.

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

BACKGROUND

In patients with atrial fibrillation, left atrial appendage closure with the Watchman device prevents thromboembolism from the left atrial appendage; however, thrombus may form on the left atrial face of the device, and then potentially embolize. Herein, we studied the incidence, predictors, and clinical outcome of device-related thrombus (DRT) using a large series of clinical trial cohorts of patients undergoing Watchman implantation.

METHODS

We studied the device arms of 4 prospective Food and Drug Administration trials: PROTECT-AF (Watchman Left Atrial Appendage System for Embolic Protection in Patients With Atrial Fibrillation) (n=463); PREVAIL (Evaluation of the Watchman LAA Closure Device in Patients With Atrial Fibrillation Versus Long Term Warfarin Therapy) (n=269); CAP (Continued Access to PROTECT AF registry) (n=566); and CAP2 (Continued Access to PREVAIL registry) (n=578). Surveillance transesophageal echocardiographs were performed at 45 days and 12 months in all patients, and also at 6 months in the randomized control trials. We assessed both the incidence of DRT during these transesophageal echocardiographs (and other unscheduled transesophageal echocardiographs), and clinical outcomes of postprocedure stroke or systemic embolism (SSE) and adjusted for CHA₂DS₂-VASC and HAS-BLED scores.

RESULTS

Of 1739 patients who received an implant (7159 patient-years follow-up; CHA₂DS₂-VASc=4.0), DRT was seen in 65 patients (3.74%). The rates of SSE with and without DRT were 7.46 and 1.78 per 100 patient-years (adjusted rate ratio, 3.55; 95% confidence interval [CI], 2.18-5.79; P<0.001), and ischemic SSE rates were 6.28 and 1.65 per 100 patient-years (adjusted rate ratio, 3.22; 95% CI, 1.90-5.45, P<0.001). On multivariable modeling analysis, the predictors of DRT were as follows: history of transient ischemic attack or stroke (odds ratio [OR], 2.31; 95% CI, 1.26-4.25; P=0.007), permanent atrial fibrillation (OR, 2.24; 95% CI, 1.19-4.20; P=0.012); vascular disease (OR, 2.06; 95% CI, 1.08-3.91; P=0.028); left atrial appendage diameter (OR, 1.06 per mm increase; 95% CI, 1.01-1.12; P=0.019); left ventricular ejection fraction (OR, 0.96 per 1% increase; 95% CI, 0.94-0.99; P=0.009). DRT and SSE both occurred in 17 of 65 patients (26.2%). Of the 19 SSE events in these patients with DRT, 9 of 19 (47.4%) and 12 of 19 (63.2%) occurred within 1 and 6 months of DRT detection. Conversely, after left atrial appendage closure, most SSEs (123/142, 86.62%) occurred in patients without DRT.

CONCLUSIONS

After left atrial appendage closure with Watchman, DRT (≈3.7%) is not frequent but, when present, is associated with a higher rate of stroke and systemic embolism.

Left Atrial Appendage Occlusion for The Unmet Clinical Needs of Stroke Prevention in Nonvalvular Atrial Fibrillation

Oral anticoagulation is the dominant strategy for stroke prevention in patients with nonvalvular atrial fibrillation. However, lifelong oral anticoagulation is associated with major issues including inappropriate dosing, nonadherence, and adverse effects. Therefore, efforts have been made to develop site-specific therapy aimed to occlude the left atrial appendage, the anatomical site accountable for more than 90% of nonvalvular atrial fibrillation-related ischemic strokes. This review focuses on the growing literature to put into perspective the risk-balance ratio of left atrial appendage occlusion.

Cardiovascular Therapies Targeting Left Atrial Appendage

Left atrial appendage (LAA) closure has evolved as an effective strategy for stroke prevention in patients with atrial fibrillation who are considered suitable for oral anticoagulation. There is strong evidence based on randomized clinical trials with 1 percutaneous device, as well as a large registry experience with several devices, regarding the safety and efficacy of this strategy. In addition, there is encouraging data regarding the effect of epicardial LAA closure on decreasing arrhythmia burden and improvements in systemic homeostasis by neurohormonal modulation. However, there are several unresolved issues regarding optimal patient selection, device selection, management of periprocedural complications including device-related thrombus, residual leaks, and pericarditis. In this review, we summarize the rationale, evidence, optimal patient selection, and common challenges encountered with mechanical LAA exclusion.

Left Atrial Appendage Closure Devices for Stroke Prevention in Patients with Non-Valvular AF

The left atrial appendage (LAA) may be involved in offloading atrial pressure during left ventricular systole. As ventricular rate increases, LAA emptying decreases during early diastole causing increased risk of thrombus formation particularly in patients with non-valvular AF (NVAF). The LAA is the site of thrombus formation in more than 90 % of patients with NVAF, so is an important target for thromboembolic prophylaxis in these patients. Anticoagulation therapy is used to treat NVAF, but it has long-term complications and may be contraindicated in some patients. Therefore, alternative strategies to reduce embolic risk in patients with AF have been developed. These include percutaneous, thoracoscopic, and open closure strategies. This study reviews the safety and efficacy of these strategies, comparing these approaches and devices with pharmacological strategies. There is little data to endorse one strategy over another. Given the minimal evidence available, recommendations in support of LAA occlusion remain weak and guidelines have called for more research and coding of endpoints for this emerging technology.