Association between device-related thrombus and the neo-appendage with left-atrial appendage occlusion devices

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.

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.

Left atrial appendage closure with the II generation Ultraseal device: An international registry. The LIGATE study

OBJECTIVES

To assess feasibility and safety of second-generation left atrial appendage closure (LAAC) Ultraseal device in patients with nonvalvular atrial fibrillation (NVAF).

BACKGROUND

LAAC with first-generation Ultraseal device (Cardia, Eagan, Minnesota) has been shown to be a feasible therapeutic option in patients with NVAF. However, there is a paucity of data regarding the novel second-generation Ultraseal device.

METHODS

All patients with NVAF undergoing second-generation Ultraseal device implantation between February 2018 and September 2020 were included in a multicenter international registry. Periprocedural and post-discharge events were collected through 6-month follow-up. Co-primary efficacy endpoints were device success and technical success while primary safety endpoint was in-hospital major adverse event (MAE) occurrence.

RESULTS

A total of 52 patients were included: mean age 75 ± 8, 30.8% women, mean HAS-BLED 3 ± 1. The device was successfully implanted in all patients. Technical success was achieved in 50 patients (96.1%). In-hospital MAEs occurred in three patients (5.8%). The incidence of 6-month all-cause death and major bleeding was 11.6% and 2.1%, respectively. No strokes, transient ischemic attacks, systemic embolisms, or device embolization were reported after discharge.

CONCLUSIONS

Second-generation Ultraseal device implantation was associated with high success rates and a low incidence of peri-procedural complications. Larger studies with longer follow-up are warranted to further evaluate the safety and the efficacy of this device, especially at long-term follow-up.

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.

The impact of hypo-attenuated leaflet thickening on haemodynamic valve deterioration following transcatheter aortic valve replacement

BACKGROUND

Hypo-attenuated leaflet thickening (HALT) may occur following transcatheter aortic valve replacement (TAVR), however, it remains unclear if HALT is a predictor of haemodynamic valve deterioration (HVD).

AIM

To determine the impact of HALT on the occurrence of HVD.

METHODS

We prospectively evaluated 186 patients for the presence of HALT at a median of 6 weeks following TAVR (Interquartile-range [IQR] 4-12 weeks). HALT depth and area were measured. HVD encompassed any of the following: mean gradient ≥20 ​mmHg with an increase in gradient ≥10 ​mmHg from baseline, Doppler velocity index reduction ≥0.1 or new moderate-to-severe valvular regurgitation. Routine echocardiograms at discharge, one month and annually, were assessed by echo-cardiologists that were blinded to the HALT status.

RESULTS

LT prevalence was 17.7% (33/186). HVD was present in 8.6% (16/186) at a median follow-up of 2 years (IQR 1-3); two required valve re-intervention and five required anticoagulation. HALT was the only independent predictor of HVD on multivariate analysis (OR 33.3, 95%CI 7.4-125). Patients with HALT were more likely to develop HVD, require repeat valve intervention and have higher trans-valvular gradients at up to 3-year follow-up. Patients with HALT had a median cumulative thickness of 2.9 ​mm (IQR 1.9-4.7) and area of 64.2 ​mm² (IQR 40.9-91.6). Thresholds for HALT in predicting HVD were a cumulative depth of 2.4 ​mm (Specificity 94.1%, Sensitivity 75.0%, AUC ​= ​0.87) and cumulative area of 28 ​mm² (Specificity 92.2%, Sensitivity 81.3%, AUC ​= ​0.86).

CONCLUSION

HALT is an independent predictor of HVD, which exhibits specific depth and area thresholds to predict HVD. CT following TAVR may determine patients at risk of HVD.

Clinical predictors and sequelae of computed tomography defined leaflet thrombosis following transcatheter aortic valve replacement at medium-term follow-up

BACKGROUND

The clinical predictors and sequelae of leaflet thrombosis (LT) following transcatheter aortic valve replacement (TAVR) is still unclear. Therefore, our aim was to determine the clinical predictors and sequelae at mid-term follow-up of computed tomography (CT)-defined LT following TAVR.

METHODS AND RESULTS

We performed a prospective evaluation with a 320-multislice CT following TAVR for the presence of LT, defined as hypo-attenuated leaflet thickening (HALT). Four-dimensional CT image-rendering was performed to determine the presence of reduced leaflet motion (RELM). 172 patients [89 (51.7%) male, mean age 82.8 ± 5.7 years] treated with commercially available TAVR device (Lotus 54%, CoreValve 32% and Sapien 3 14%) were included, with median CT-scan at 6.0 weeks post-TAVR. Prevalence of HALT was 14.0% (24 cases) and RELM was 9.8% (17 cases). On multivariate analysis, patients with HALT were less prescribed oral anticoagulation (OAC) (OR 9.9), received larger TAVR prostheses (OR 5.7) and higher rates of moderate-severe para-valvular regurgitation (PVR) (OR 16.3). There was no difference in clinical outcomes at a median follow-up of 2.3 years. Patients with RELM had significantly higher transvalvular gradients after discharge when compared to those without RELM.

CONCLUSIONS

Absence of OAC, large TAVR prostheses and moderate-severe PVR were predictors for LT. Transvalvular gradients were higher in patients that developed RELM but not HALT. Further studies are warranted to determine the long-term impact of LT on TAVR durability. Prevalence of different sub-types of CT-defined LT (HALT and RELM) and the clinical predictors of developing LT following TAVR. CT computed tomography, HALT hypo-attenuated leaflet thickening, LT leaflet thrombosis, RELM reduced leaflet motion, TAVR transcatheter aortic valve replacement.

Modification of the left atrial appendage and its role in stroke risk reduction with non-valvular atrial fibrillation

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Evidence on surgical LAA excision has been limited to retrospective studies and registries.

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Surgical LAA excision is associated with high rates of post-operative atrial fibrillation burden.

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Watchman is equivalent to oral anticoagulants in high-bleeding risk AF patients.

Atrial fibrillation is one of the most common cardiovascular disorders encountered by clinicians in clinical practice. Patients with atrial fibrillation are at risk of cerebrovascular and systemic embolic events, which may be attenuated by commencement of anticoagulation therapy. Even so, due to extremely high bleeding risk certain patients may not be suitable for long-term anticoagulation therapy. The left atrial appendage is a common site for thrombus formation in patients with atrial fibrillation. Left atrial appendage exclusion, either surgical or percutaneous, has been performed to ostensibly reduce the risk of cerebrovascular events and potentially minimise or omit anticoagulation therapy in select patients. This review summarises the role of the left atrial appendage in cerebrovascular events, current evidence with modification of the left atrial appendage and future trials that may change practice with these procedures.