Rationale and design of a randomized clinical trial to compare two antithrombotic strategies after left atrial appendage occlusion: double antiplatelet therapy vs. apixaban (ADALA study)

Early and late hospital readmissions after percutaneous left atrial appendage closure

INTRODUCTION AND OBJECTIVES

Percutaneous left atrial appendage closure (LAAC) has emerged as a nonpharmacological alternative for the prevention of thromboembolic events in patients with nonvalvular atrial fibrillation. However, there are few data on readmissions after LACC. The aim of this study was to determine the rate of early (≤ 30 days) and late (31-365 days) readmission after LAAC, and to assess the predictors and clinical impact of rehospitalization.

METHODS

This multicenter study included 1419 consecutive patients who underwent LAAC. The median follow-up was 33 [17-55] months, and follow-up was complete in all but 54 (3.8%) patients. The primary endpoint was readmissions for any cause. Logistic regression and Cox regression analysis were performed to determine the predictors of readmission and its clinical impact.

RESULTS

A total of 257 (18.1%) patients were readmitted within the first year after LAAC (3.2% early, 14.9% late). The most common causes of readmission were bleeding (24.5%) and heart failure (20.6%). A previous gastrointestinal bleeding event was associated with a higher risk of early readmission (OR, 2.65; 95%CI, 1.23-5.71). The factors associated with a higher risk of late readmission were a lower body mass index (HR, 0.96-95%CI, 0.93-0.99), diabetes (HR, 1.38-95%CI, 1.02-1.86), chronic kidney disease (HR, 1.60; 95%CI, 1.21-2.13), and previous heart failure (HR, 1.69; 95%CI, 1.26-2.27). Both early (HR, 2.12-95%CI, 1.22-3.70) and late (HR, 1.75; 95%CI, 1.41-2.17) readmissions were associated with a higher risk of 2-year mortality.

CONCLUSIONS

Readmissions within the first year after LAAC were common, mainly related to bleeding and heart failure events, and associated with patients' comorbidity burden. Readmission after LAAC confered a higher risk of mortality during the first 2 years after the procedure.

Low-Dose Direct Oral Anticoagulation vs Dual Antiplatelet Therapy After Left Atrial Appendage Occlusion: The ADALA Randomized Clinical Trial

Importance

Optimal antithrombotic therapy after percutaneous left atrial appendage occlusion (LAAO) is not well established as no randomized evaluation has been performed to date.

Objective

To compare the efficacy and safety of low-dose direct oral anticoagulation (low-dose DOAC) vs dual antiplatelet therapy (DAPT) for 3 months after LAAO.

Design, Setting, and Participants

The ADALA (Low-Dose Direct Oral Anticoagulation vs Dual Antiplatelet Therapy After Left Atrial Appendage Occlusion) study was an investigator-initiated, multicenter, prospective, open-label, randomized clinical trial enrolling participants from June 12, 2019, to August 28, 2022 from 3 European sites. Patients who underwent successful LAAO were randomly assigned 1:1 to low-dose DOAC vs DAPT for 3 months after LAAO. The study was prematurely terminated when only 60% of the estimated sample size had been included due to lower recruitment rate than anticipated due to the COVID-19 pandemic.

Interventions

The low-dose DOAC group received apixaban, 2.5 mg every 12 hours, and the DAPT group received aspirin, 100 mg per day, plus clopidogrel, 75 mg per day, for the first 3 months after LAAO.

Main Outcomes and Measures

The primary end point was a composite of safety (major bleeding) and efficacy (thromboembolic events including stroke, systemic embolism, and device-related thrombosis [DRT]) within the first 3 months after successful LAAO. Secondary end points included individual components of the primary outcome and all-bleeding events.

Results

A total of 90 patients (mean [SD] age, 76.6 [8.1] years; 60 male [66.7%]; mean [SD] CHADS-VASc score, 4.0 [1.5]) were included in the analysis (44 and 46 patients in the low-dose DOAC and DAPT groups, respectively). A total of 53 patients (58.8%) presented with previous major bleeding events (60 gastrointestinal [66.7%] and 16 intracranial [17.8%]). At 3 months, low-dose DOAC was associated with a reduction of the primary end point compared with DAPT (2 [4.5%] vs 10 [21.7%]; hazard ratio, 0.19; 95% CI, 0.04-0.88; P = .02). Patients in the low-dose DOAC group exhibited a lower rate of DRT (0% vs 6 [8.7%]; P = .04) and tended to have a lower incidence of major bleeding events (2 [4.6%] vs 6 [13.0%]; P = .17), with no differences in thromboembolic events such as stroke and systemic embolism between groups (none in the overall population).

Conclusions and Relevance

This was a small, randomized clinical trial comparing different antithrombotic strategies after LAAO. Results show that use of low-dose DOAC for 3 months after LAAO was associated with a better balance between efficacy and safety compared with DAPT. However, the results of the study should be interpreted with caution due to the limited sample size and will need to be confirmed in future larger randomized trials.

Trial Registration

ClinicalTrials.gov Identifier: NCT05632445.

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.

Der interventionelle Vorhofohrverschluss: eine Alternative zur oralen Antikoagulation

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

Incidence and Predictors of Clinically Significant Bleedings after Transcatheter Left Atrial Appendage Closure

BACKGROUND

Transcatheter left atrial appendage closure (LAAC) is performed in patients unsuitable for long-term anticoagulation, predominantly due to prior bleeding events. The study aimed to investigate the incidence and predictors of clinically significant bleeding (CSB) post-LAAC.

METHODS

Consecutive patients after LAAC with an Amplatzer or WATCHMAN device were analyzed (05.2014-11.2019). Bleeding was classified as CSB when associated with at least one of the following: death, ≥2 g/dL hemoglobin drop, ≥2 blood units transfusion, critical anatomic site, or hospitalization/invasive procedure.

RESULTS

Among 195 patients (age 74 (68-80), 43.1% females, HAS-BLED score 2.0 (2.0-3.0)), during median follow-up of 370 (IQR, 358-392) days, there were 15 nonprocedural CSBs in 14 (7.2%) patients. Of those, 9 (60.0%) occurred during postprocedural dual antiplatelet therapy (DAPT) (median 46 (IQR: 16-60) days post-LAAC) vs. 6 (40%) after DAPT discontinuation (median 124 (81-210) days post-LAAC), translating into annualized CSB rates of 14.0% (per patient-year on DAPT) vs. 4.6% (per patient-year without DAPT). In 92.9% (13/14) of patients, the post-LAAC nonprocedural CSB was a recurrence from the same site as bleeding pre-LAAC. In the multivariable model, admission systolic blood pressure (SBP) > 127 mmHg (HR = 10.73, 1.37-84.26, p = 0.024), epistaxis history (HR = 5.84, 1.32-25.89, p = 0.020), permanent atrial fibrillation (AF) (HR = 4.55, 1.20-17.20, p = 0.025), and prior gastrointestinal bleeding (HR = 3.35, 1.01-11.08, p = 0.048) predicted post-LAAC CSB.

CONCLUSIONS

Nonprocedural CSBs after LAAC, with a similar origin as the pre-LAAC bleedings, were observed predominantly during postprocedural DAPT and predicted by elevated admission SBP, prior epistaxis, permanent AF, and gastrointestinal bleeding history. Whether a more reserved post-LAAC antiplatelet regimen and stringent blood pressure control may improve LAAC outcomes remains to be studied.

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.

Treatment of device related thrombosis after left atrial appendage occlusion: Initial experience with low-dose apixaban

BACKGROUND

Left atrial appendage (LAA) closure devices require short-term postprocedural oral antithrombotic therapy (AT) to prevent device-related thrombosis (DRT) until device endothelialization occurs. Currently, there is no consensus regarding the optimal AT strategy for DRT prevention.

METHODS

The purpose of our case series is to summarize our experience using apixaban at reduced doses for effectively treating DRT.

RESULTS

Among a total of 180 patients, 11 patients (6.1%) presented DRT and 4 were specifically treated with low-dose apixaban (2.5 mg/12 h). The mean CHA2DS2-VASc and HAS-BLED scores were high [5 (SD ±1.2) and 3.25 (SD ±0.5), respectively] and all patients had history of a major hemorrhagic event (BARC Score ≥3) mostly gastrointestinal (n = 3). An Amplazer Amulet device was implanted in 3 patients, and a LAmbre system in one patient. AT strategy at the time of DRT diagnosis was consistently single antiplatelet therapy in all patients. Following DRT diagnosis, reduced dose of apixaban was initiated in all the patients. No major or minor bleeding events occurred during apixaban administration.

CONCLUSIONS

Apixaban low dose regimen could be a feasible option to prevent DRT while keeping a low risk of bleeding.

Low Dose of Direct Oral Anticoagulants after Left Atrial Appendage Occlusion

The optimal antithrombotic strategy following left atrial appendage occlusion (LAAO) is not yet clearly established. Low-dose non-vitamin K antagonist oral anticoagulants (NOAC) might represent a valid alternative, but data regarding their usage is scarce. The aim of this study was to examine the efficacy and safety of low-dose NOAC compared to single (SAPT) or dual antiplatelet therapies (DAPT) after LAAO. We included consecutive patients with non-valvular atrial fibrillation who underwent LAAO and received low-dose apixaban, SAPT, or DAPT at discharge. The primary objective of this study included an efficacy endpoint (thromboembolic events and device related thrombosis (DRT)) and a safety endpoint (incidence of major bleeding) within the first three months after LAAO. A total of 139 patients were included. This group involved SAPT in 26 (18%), DAPT in 73 (53%), and apixaban in 40 (29%) patients. Follow-up at three-months showed no significant differences in the primary efficacy endpoint (2 (8%) SAPT, 3 (4%) DAPT and 0 (0%) apixaban; p value = 0.25). In contrast, the primary safety endpoint occurred more frequently in DAPT patients (7 (10%) DAPT, 0 (0%), SAPT and 0 with apixaban; p value = 0.03). Combining both efficacy and safety outcomes, low dose apixaban had a lower rate of events (2 (8%) with SAPT, 9 (12%) with DAPT and 0 (0%) with apixaban; p = 0.046). Low-dose apixaban after LAAO may be a valid alternative to DAPT and SAPT as depicted by the reduction in the occurrence of major bleedings and combined DRT/major bleedings respectively. Randomized data will be necessary to validate this strategy.