Incomplete neo-endothelialization of left atrial appendage closure devices is frequent after 6 months: a pilot imaging study

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.

Position Statement on Cardiac Computed Tomography Following Left Atrial Appendage Occlusion

Left atrial appendage occlusion (LAAO) is rapidly growing as valid stroke prevention therapy in atrial fibrillation. Cardiac imaging plays an instrumental role in preprocedural planning, procedural execution, and postprocedural follow-up. Recently, cardiac computed tomography (CCT) has made significant advancements, resulting in increasing use both preprocedurally and in outpatient follow-up. It provides a noninvasive, high-resolution alternative to the current standard, transesophageal echocardiography, and may display advantages in both the detection and characterization of device-specific complications, such as peridevice leak and device-related thrombosis. The implementation of CCT in the follow-up after LAAO has identified new findings such as hypoattenuated thickening on the atrial device surface and left atrial appendage contrast patency, which are not readily assessable on transesophageal echocardiography. Currently, there is a lack of standardization for acquisition and interpretation of images and consensus on definitions of essential findings on CCT in the postprocedural phase. This paper intends to provide a practical and standardized approach to both acquisition and interpretation of CCT after LAAO based on a comprehensive review of the literature and expert consensus among European and North American interventional and imaging specialists.

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.

Left Atrial Appendage Occlusion and Post-procedural Antithrombotic Management

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

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.

The Effect of Peri-Device Leaks on Ischaemic Stroke/Transient Ischaemic Attack/Systemic Embolism after Left Atrial Appendage Closure: A Systematic Review and Meta-Analysis

BACKGROUND

Left atrial appendage closure (LAAC) is a safe and effective method for preventing embolic events in patients with non-valvular atrial fibrillation. However, peri-device leaks (PDLs) are sometimes unavoidable. Controversy exists regarding whether PDLs lead to embolic events.

OBJECTIVES

This study aimed to explore the association between PDLs and embolic events, including ischaemic stroke, transient ischaemic attacks (TIAs), and systemic embolism (SE).

METHODS

We conducted a systematic search of the PubMed, Web of Science, MEDLINE, and Cochrane Library databases for studies published up to September 25, 2022, to compare the rate of ischaemic stroke/TIA/SE between the PDL group and the non-PDL group after LAAC.

RESULTS

Thirteen studies comprising 54,405 patients were included in the meta-analysis. The PDL group detected by transoesophageal echocardiography (TEE) had a significantly higher rate of ischaemic stroke/TIA/SE than the non-PDL group (OR: 1.20, 95% CI: 1.08-1.33, p = 0.0009). However, no difference in ischaemic stroke/TIA/SE was found between the PDL and non-PDL subgroups of the cardiac computed tomography angiography (CCTA) group (OR: 1.12, 95% CI: 0.51-2.50, p = 0.77). CCTA and TEE showed different rates of PDL detection, with the CCTA group having a higher rate of PDL detection (p < 0.0001), especially for trivial leaks.

CONCLUSIONS

PDL detected by TEE increases the risk of embolic events after LAAC. However, no association was found between PDL and ischaemic stroke/TIA/SE in the CCTA group, which showed a higher rate of PDL detection than TEE, particularly for trivial leaks. In the future, CCTA may be used to explore the relationship between PDL size and ischaemic stroke/TIA/SE.

Percutaneous left atrial appendage closure in patients with hypertrophic cardiomyopathy and persistent atrial fibrillation: 3-year-followed case series

Hypertrophic cardiomyopathy (HCM) patients with atrial fibrillation (AF) are at high risk for stroke. Left atrial appendage closure (LAAC) is a promising alternative for stroke prevention in AF patients. We aimed to review the clinical outcomes of patients with AF and HCM at our center. We reviewed 673 patients who underwent LAAC implantation from 2014 to 2021 in a tertiary center, of whom 15 had HCM. AF Patients with HCM were compared with sex and age matched controls who also underwent LAAC. From 2014 to 2021, 673 AF patients received LAAC in a single center, of whom, 15 patients had HCM. LAAC devices were successfully implanted in 14 HCM patients and 59 patients in the control group. During the follow-up period (median 1151 days range: 132-2457 days), 2 HCM patient had ischemic strokes. There were another 2 HCM patients who had sudden cardiac death (SCD). Compared with the control, HCM patients had higher cumulative rate of combined death and stroke (26.67% vs 3.33%, P = .024). In our initial clinical experience, the cumulative stroke and death rate of the HCM patients was significantly higher than that of the non-HCM patients.

Clinical relevance of incomplete device endothelialization after left atrial appendage closure

PURPOSE

This study aimed to assess the incidence, potential risk factors and clinical impact of incomplete device endothelialization(IDE) after left atrial appendage closure (LAAC).

METHODS

A total of 101 consecutive patients with nonvalvular atrial fibrillation (AF) who underwent successful LAAC and received antithrombotic treatment using a standard regimen were prospectively followed up to 6 months after the procedure. The status of device endothelialization and device-related thrombus (DRT) were evaluated using cardiac computed tomography (CT). Major adverse cardio-cerebral events (MACCE) including all-cause death, heart failure(HF) hospitalization, acute ischemic stroke, transient ischemic attack(TIA), peripheral vascular embolism, and major bleeding were recorded.

RESULTS

IDE was detected in 65 (64.4%) patients. Patients with IDE or complete device endothelialization (CDE) did not significantly differ with respect to baseline clinical characteristics and interventional procedure features. Multivariate analysis model revealed that persistent AF, left atrial appendage ostial diameter and left atrial size were independent risk factors for IDE. During 6-month follow-up, the incidence of DRT was 4.6% in patients with IDE and 2.8% in those with CDE, respectively (p > 0.05), and the overall rate of MACCE was non-significantly higher in the IDE group (7.7% vs. 2.8%, p = 0.32).

CONCLUSION

IDE is common after LAAC, especially in patients with persistent AF, higher left atrial appendage ostial diameter and left atrial size. IDE confers an increased risk for DRT, but may be not necessarily associated with thromboembolic events and poor clinical outcome, providing careful monitoring and continued antithrombotic therapy are given.

Assessment of Device Neoendothelialization With Cardiac Computed Tomography Angiography After Transcatheter Closure of Atrial Septal Defect

Although the transcatheter closure of atrial septal defect was established as the treatment of choice several decades ago, the process of device neoendothelialization (NE) in humans is not well understood. We aimed to measure the extent of device NE using cardiac computed tomography angiography and analyze its risk factors.

Effectiveness and safety of transcatheter left atrial appendage closure

Atrial fibrillation (AF) is responsible for cardiogenic stroke. Since left atrial appendage (LAA) is a cause of most of cardiac thrombus, LAA closure is an emerging novel stroke prevention procedure for patients with AF alternative to anticoagulation. WATCHMAN LAA Closure device (Boston Scientific, Marlborough, MA, USA) is the only approved device in the USA and Japan. The device is indicated in high bleeding risk and high stroke risk non-valvular AF patients. Cardiac tamponade, stroke, and device embolization are typical procedural complications. Procedural complication rate is reduced with implanters' experience and matured procedure steps. Several randomized trials demonstrated procedure safety and efficacy of the device. The device resulted in similar thromboembolic event rates but significantly reduced bleeding events compared to anticoagulants. After the procedure, optimal post procedural antithrombotic drug regimen has not been fully investigated. Also, device-related thrombosis can be a new issue. Modification of the device can improve issues, but not fully solve it. Tailor made treatment based on the individual risk by heart team communication with neurologists is essential to treat patients.

The Impact of Dabigatran and Rivaroxaban on Variation of Platelet Activation Biomarkers and DRT Following Percutaneous Left Atrial Appendage Closure

Background: The current post-procedure antithrombotic recommendation for left atrial appendage closure (LAAC) remains empiric. This study was designed to compare variations in platelet activation biomarkers and device-related thrombosis (DRT) under different antithrombotic regimens following LAAC. Methods: This study enrolled 105 consecutive patients with atrial fibrillation who underwent LAAC successfully and received post-procedure anticoagulation with either dabigatran (N = 33) or rivaroxaban (N = 72). After 3 months of anticoagulation treatment, thromboelastogram was used to evaluate thrombin receptor-activating peptide (TRAP)-induced platelet aggregation (PA). Measurements of platelet activation biomarkers, including thrombin-antithrombin complex (TAT), P-selectin, von Willebrand disease (vWF), and CD40L, were performed immediately before the LAAC procedure and after 3 months of post-procedure anticoagulation. Repeated transesophageal echocardiography was performed to evaluate DRT during follow-ups. Results: Three (4.2%) patients in the rivaroxaban and 4 (12.1%) patients in the dabigatran group experienced DRT events (odds ratio (OR) = 0.315, 95% confidence interval (95%CI): 0.066-1.489, p = 0.129) during follow-ups. The TRAP-induced PA was statistically significantly higher in the dabigatran group (62.9% vs 59.7%, p = 0.028*). Statistically significant increases in plasma concentration of TAT, P-selectin, and vWF were observed after 3 months of exposure to dabigatran when compared with rivaroxaban. An increased expression of platelet activation biomarkers was observed in DRT subjects compared with non-DRT subjects in terms of P-selectin and vWF (65.28 ± 13.93 ng/L vs 32.14 ± 12.11 ng/L, p = 0.037; 501.92 ± 106.48 U/L vs 280.98 ± 54.10 U/L, p = 0.045; respectively). Multivariate regression analysis indicated that the use of dabigatran might be an independent predictor of DRT (p = 0.022; OR = 4.366, 95%CI: 0.434-10.839). Furthermore, the CHA2DS2-VASc score (OR = 2.076, p = 0.016) and CD40L levels (OR = 1.015, p = 0.021) were independent predictors of increased D-dimer levels. Conclusions: Post-LAAC anticoagulation with dabigatran may increase the risk of DRT by enhancing platelet reactivity. In light of this potential increased risk in DRT, the authors recommend against using dabigatran for post-procedural anticoagulation in patients who have undergone LAAC.