Low Dose of Direct Oral Anticoagulants after Left Atrial Appendage Occlusion

Practical guide on left atrial appendage closure for the non-implanting physician: an international consensus paper

A significant proportion of patients who suffer from atrial fibrillation (AF) and are in need of thromboembolic protection are not treated with oral anticoagulation or discontinue this treatment shortly after its initiation. This undertreatment has not improved sufficiently despite the availability of direct oral anticoagulants which are associated with less major bleeding than vitamin K antagonists. Multiple reasons account for this, including bleeding events or ischaemic strokes whilst on anticoagulation, a serious risk of bleeding events, poor treatment compliance despite best educational attempts, or aversion to drug therapy. An alternative interventional therapy, which is not associated with long-term bleeding and is as effective as vitamin K anticoagulation, was introduced over 20 years ago. Because of significant improvements in procedural safety over the years, left atrial appendage closure, predominantly achieved using a catheter-based, device implantation approach, is increasingly favoured for the prevention of thromboembolic events in patients who cannot achieve effective anticoagulation. This management strategy is well known to the interventional cardiologist/electrophysiologist but is not more widely appreciated within cardiology or internal medicine. This article introduces the devices and briefly explains the implantation technique. The indications and device follow-up are more comprehensively described. Almost all physicians who care for adult patients will have many with AF. This practical guide, written within guideline/guidance boundaries, is aimed at those non-implanting physicians who may need to refer patients for consideration of this new therapy, which is becoming increasingly popular.

Minimally invasive left atrial appendage occlusion plus reduced dose direct oral anticoagulant to prevent stroke in patients with atrial fibrillation-the LAAO-PlusRE

The onset of atrial fibrillation (AF) has a direct association with left atrial appendage (LAA) function, as demonstrated by recent studies demonstrating the link between left atrial (LA) wall fibrosis, impaired contractility, and the development of AF. Non-valvular AF (NVAF) affects almost 30 million people worldwide, with this number expected to increase in the next 20 years. It is the main cause of ischemic stroke, with significant subsequent economic and social impact. Currently, the mainstay of stroke prevention in patients with NVAF is oral anticoagulation (OAC), which reduces the incidence of ischemic events at the stake of increased hemorrhagic events. Despite the introduction and widespread use of direct oral anticoagulants (DOACs), which almost completely replaced vitamin K antagonists (VKAs), the adherence to OAC is still low, hindering the efficacy of stroke prevention. Percutaneous LAA occlusion (LAAO) is now indicated (class IIB) in patients with NVAF at increased ischemic risk who cannot undergo OAC. Recently published data demonstrated that a reduced dose of DOAC after percutaneous LAAO is superior to long-term dual antiplatelet therapy (DAPT) for stroke prevention in the mid-term. One of the possible pitfalls of percutaneous LAAO is postprocedural peri-device leaks (PDLs) that have been associated with increased thromboembolic events. According to LAAOS III results, surgical LAAO during cardiac surgery brings a 33% reduction in risk of stroke at five years, independently from the OAC regimen with a high rate of complete appendage occlusion. The combination of surgical LAAO and reduced dose DOAC might ensure adequate embolic prevention, lowering the hemorrhagic risk. The present manuscript aims to describe the rationale and design of the Minimally Invasive Left Atrial Appendage Occlusion Plus REduced Dose DOAC To Prevent Stroke In Patients With Atrial Fibrillation Randomized Clinical Trial (LAAO-PlusRE).

Short-term antiplatelet versus anticoagulant therapy after left atrial appendage closure: a systematic review and meta-analysis

This meta-analysis compared the efficacy and safety of different antithrombotic regimens after left atrial appendage closure (LAAC). PubMed, Embase, Medline, Cochrane Library databases were systematically searched from their inception to March 2023. Patients were divided into short-term oral anticoagulation (OAC) group and antiplatelet therapy (APT) group. The incidence of events were performed using RevMan 5.4. The events including device-related thrombus (DRT), ischemic stroke/systemic embolization (SE), major bleeding, any bleeding, any major adverse event and all-cause mortality. Subgroup analysis were based on OAC alone or OAC plus single antiplatelet therapy (SAPT) in OAC group. Oral anticoagulants include warfarin and direct oral anticoagulant (DOAC). Fourteen studies with 35,166 patients were included. We found that the incidence of DRT (OR = 0.49, 95% CI 0.36-0.66, P＜0.0001) and all-cause mortality (OR = 0.71, 95% CI 0.57-0.89, P = 0.002) were significantly lower in OAC group than APT group. However, there was no statistical differences in the incidence rates of ischemic stroke/SE (OR = 0.77, 95% CI 0.49-1.20, P = 0.25), major bleeding (OR = 0.84, 95% CI 0.55-1.27, P = 0.84), any bleeding (OR = 0.83, 95% CI 0.56-1.22, P = 0.34) and any major adverse event (OR = 0.56, 95% CI 0.30-1.03, P = 0.06) in the two groups. Subgroup analysis found that the incidence of DRT, all-cause mortality and any major adverse event in OAC monotherapy were lower than that in APT group (P＜0.05), but not statistically different from other outcome. The incidence of DRT, all-cause mortality, any major adverse event and any bleeding in DOAC were significantly better than APT group (P＜0.05). While warfarin only has better incidence of DRT than APT (P＜0.05), there was no statistical difference between the two groups in other outcome (P＞0.05). The incidence of DRT was significantly lower than APT group (P＜0.05), major bleeding were higher, and the rest of the outcome did not show any statistically significant differences(P＞0.05) when OAC plus SAPT. Based on the existing data, short-term OAC may be favored over APT for patients who undergo LAAC. DOAC monotherapy may be favored over warfarin monotherapy or OAC plus APT, when selecting anticoagulant therapies.

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.

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.

Antithrombotic Regimen After Percutaneous Left Atrial Appendage Closure - A Real-World Study

BACKGROUND

Antithrombotic therapy after left atrial appendage closure (LAAC) in patients at high risk of bleeding remains controversial. We present real-world clinical outcomes of LAAC.Methods and Results: Data from 74 consecutive patients who received LAAC therapy between January 2020 and June 2022 were analyzed. Patients received 1 of 3 antithrombotic therapies according to the bleeding risk category or clinical event. Regimen 1 was based on a prior study, regimen 2 comprised a lower antiplatelet drug dose without dual antiplatelet therapy, and regimen 3 was antiplatelet drug administration for as long as possible to patients with uncontrollable bleeding who were required to stop anticoagulant drugs. Overall, 73 (98.6%) procedures were successful. Of them, 16 (21.9%) patients were selected for regimen 1, 46 (63.0%) for regimen 2, and 11 (15.1%) for regimen 3. Device-related thrombosis (13% vs. 0% vs. 0%, P=0.0257) only occurred with regimen 1. There was no difference in major bleeding event rates (6% vs. 2% vs. 9%, P=0.53).

CONCLUSIONS

The post-LAAC antithrombotic regimen was modified without major concerns.

Short-term antithrombotic strategies after left atrial appendage occlusion: a systematic review and network meta-analysis

Background: Percutaneous left atrial appendage occlusion (LAAO) has emerged as a stroke prevention strategy in patients with nonvalvular atrial fibrillation (NVAF), and these patients were required to receive antithrombotic therapy post-procedure. However, the optimal antithrombotic strategy after LAAO remains controversial. This study explored the safety and efficacy of different antithrombotic strategies after LAAO through a network comparison method. Methods: We systematically searched the MEDLINE, Embase, and Cochrane Library databases for studies that reported the interested efficacy and safety outcomes (stroke, device-related thrombus (DRT), and major bleeding) of different antithrombotic strategies [DAPT (dual antiplatelet therapy), DOACs (direct oral anticoagulants), and VKA (vitamin k antagonist)] in patients who had experienced LAAO. Pairwise comparisons and network meta-analysis were performed for the interested outcomes. Risk ratios (RRs) with their confidence intervals (CIs) were calculated using a random-effects model. The rank of the different strategies was calculated using the surface under the cumulative ranking curve (SUCRA). Results: Finally, 10 observational studies involving 1,674 patients were included. There was no significant difference in stroke, DRT, and major bleeding among the different antithrombotic strategies (DAPT, DOACs, and VKA). Furthermore, DAPT ranked the worst in terms of stroke (SUCRA: 19.8%), DRT (SUCRA: 3.6%), and major bleeding (SUCRA: 6.6%). VKA appeared to be superior to DOACs in terms of stroke (SUCRA: 74.9% vs. 55.3%) and DRT (SUCRA: 82.3% vs. 64.1%) while being slightly inferior to DOACs in terms of major bleeding (SUCRA: 71.0% vs. 72.4%). Conclusion: No significant difference was found among patients receiving DAPT, DOACs, and VKA in terms of stroke, DRT, and major bleeding events after LAAO. The SUCRA indicated that DAPT was ranked the worst among all antithrombotic strategies due to the higher risk of stroke, DRT, and major bleeding events, while VKAs were ranked the preferred antithrombotic strategy. However, DOACs are worthy of consideration due to their advantage of convenience.

Management of oral anticoagulant therapy after intracranial hemorrhage in patients with atrial fibrillation

Intracranial hemorrhage (ICH) is considered a potentially severe complication of oral anticoagulants (OACs) and antiplatelet therapy (APT). Patients with atrial fibrillation (AF) who survived ICH present both an increased ischemic and bleeding risk. Due to its lethality, initiating or reinitiating OACs in ICH survivors with AF is challenging. Since ICH recurrence may be life-threatening, patients who experience an ICH are often not treated with OACs, and thus remain at a higher risk of thromboembolic events. It is worthy of mention that subjects with a recent ICH and AF have been scarcely enrolled in randomized controlled trials (RCTs) on ischemic stroke risk management in AF. Nevertheless, in observational studies, stroke incidence and mortality of patients with AF who survived ICH had been shown to be significantly reduced among those treated with OACs. However, the risk of hemorrhagic events, including recurrent ICH, was not necessarily increased, especially in patients with post-traumatic ICH. The optimal timing of anticoagulation initiation or restarting after an ICH in AF patients is also largely debated. Finally, the left atrial appendage occlusion option should be evaluated in AF patients with a very high risk of recurrent ICH. Overall, an interdisciplinary unit consisting of cardiologists, neurologists, neuroradiologists, neurosurgeons, patients, and their families should be involved in management decisions. According to available evidence, this review outlines the most appropriate anticoagulation strategies after an ICH that should be adopted to treat this neglected subset of patients.

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.

Treatment of Persistent Left Atrial Appendage Thrombus in Patients with Atrial Fibrillation on Adequate Oral Anticoagulation: Pathways of Care for All-comers and Heart Failure Patients

In patients with AF, the presence of left atrial/left atrial appendage (LA/LAA) thrombus is related to an increased risk of thromboembolic events. Anticoagulation therapy, either with vitamin K antagonists or novel oral anticoagulants (NOACs) is therefore mandatory in AF with LA/LAA thrombus in order to lower the risk of stroke or other systemic embolic events. Despite the efficacy of these treatments, some patients will have persistent LAA thrombus remaining or may have contraindications to oral anticoagulation. Currently, little is known about the occurrence, risk factors and resolution rate of LA/LAA thrombus in patients who are already under optimal chronic oral anticoagulation, including vitamin K antagonists or NOACs. The common action in clinical practice in this scenario is switching from one to another anticoagulant drug exhibiting a different mechanism of action. Repeated cardiac imaging is then advised within several weeks to visually verify thrombus dissolution. Finally, there is a substantial scarcity of data on the role and optimal use of NOACs after LAA occlusion. The aim of this review is to critically evaluate data and provide up-to-date information on the best antithrombotic strategies in this challenging clinical scenario.

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.

New Perspectives on Risk Stratification and Treatment in Patients with Atrial Fibrillation: An Analysis of Recent Contributions on the Journal of Cardiovascular Disease and Development

The medical approach to atrial fibrillation (AF) underwent a paradigm shift over time, evolving from considering AF as a simple arrhythmic phenomenon to a complex nosological entity [...].

Risk of device-related thrombosis following short-term oral anticoagulation with low-dose dabigatran versus warfarin after Watchman left atrial appendage occlusion

BACKGROUND

Percutaneous left atrial appendage occlusion (LAAO) provides an alternative for poor candidates for long-term oral anticoagulation (OAC). To prevent device-related thrombosis (DRT), OAC should be continued for the first 45 days to allow complete endothelialization post-LAAO implantation. Whereas, evidence is limited on the feasibility and safety of direct oral anticoagulants (DOACs) used after LAAO.

METHODS

This was a retrospective observational single-center study of AF patients undergoing LAAO with a Watchman device and receiving either low-dose dabigatran (110mg twice daily) or warfarin in the peri- and post-procedural period for 45 days. Transesophageal echocardiography was scheduled to perform at 6 weeks, 6 months, and 12 months after the procedure to assess the stability of the device and to detect DRT. Incidence of thromboembolic and bleeding events were also evaluated during the follow-up period.

RESULTS

There were a total of 84 patients who successfully underwent Watchman implantation, with 38 patients (45.2%) receiving low-dose dabigatran and 46 patients (54.8%) using warfarin post-LAAO. Peri-procedural complications occurred in 10 patients, with 3 patients in the dabigatran group and 7 patients in the warfarin group (7.9% vs. 15.2%, p = 0.30). During the 12-month follow-up, 1 patient experienced major bleeding and 16 patients suffered minor bleeding in the warfarin group, while 5 patients treated with dabigatran had minor bleeding (34.8% vs. 13.2%, p = 0.02). Besides, 6 DRT (15.8%) were detected in dabigatran groups, and the incidence was higher than in the warfarin group (15.8% vs. 2.2%, p = 0.03). No DRT-related ischemic events were found.

CONCLUSIONS

This study suggested that short-term low-dose dabigatran (110 mg twice daily) could significantly decrease the risk of bleeding compared with warfarin at the expense of increased risk of DRT post-LAAO. Therefore, low-dose dabigatran should be used with caution for post-implant anticoagulation of LAAO. Further studies are urgently needed on the feasibility and safety of DOACs post-LAAO.