Background:
Antithrombotic strategies following left atrial appendage occlusion (LAAO) remain variable, and the safety of aspirin (ASA) monotherapy is still under discussion. This study evaluated the incidence of device-related thrombus (DRT) at the scheduled 3-month follow-up after LAAO in patients receiving ASA monotherapy compared with dual antiplatelet therapy (DAPT). Previous studies have reported DRT rates of approximately 3–6% irrespective of the postprocedural antithrombotic regimen (Alkhouli et al., JACC Intv 2023).
Methods:
All consecutive patients from a single-centre registry undergoing LAAO with Amplatzer Amulet™ device between 09/2021 and 11/2025 were analysed. Inclusion for the primary analysis required a transoesophageal echocardiography (TEE) between 80 and 120 days post-procedure. The primary endpoint was the presence of DRT at 3-month follow-up. Antithrombotic strategy (ASA monotherapy vs. DAPT) was determined individually, based on bleeding and thromboembolic risk.
Results:
Among 159 registry entries (mean age 77.7 ± 8.3 years, 63.5% male), 73 patients underwent TEE at 3 months (mean follow-up 89.4 ± 39.1 days). The mean CHA₂DS₂-VA- and HAS-BLED scores were 4.4 ± 1.1 and 3.3 ± 0.6. All patients included in the analysis had a documented history of bleeding. Specifically, gastrointestinal bleeding was reported in 52% (n = 38), intracranial bleeding in 26% (n = 19), cutaneous bleeding in 4% (n = 3), nasal bleeding in 4% (n = 3), and other bleeding manifestations in 13% (n = 10).
Among the study population, 15 patients received DAPT, with a mean age of 76.3 ± 11.0 years; 80% (n = 12) were male. The mean CHA₂DS₂-VA- and HAS-BLED-scores were 4.6 ± 1.1 and 3.3 ± 0.8. Arterial hypertension was present in all patients (100%, n = 15), diabetes mellitus in 26.7% (n = 4), and coronary artery disease in 46.7% (n = 7). DRT occurred in one patient (6.6%). No peri-device leaks (PDL) were observed.
The majority of patients (n = 58) were treated with ASA monotherapy. Their mean age was 77.7 ± 7.7 years, and 58.6% (n = 34) were male. The mean CHA₂DS₂-VA- and HAS-BLED scores were 4.1 ± 1.0 and 3.3 ± 0.6. Cardiovascular comorbidities included arterial hypertension in 93% (n = 54), diabetes mellitus in 38% (n = 22), and coronary artery disease in 22% (n = 13). DRT was observed in two patients (3.4%). PDL were also detected in two patients (3.4%).
No statistically significant difference in DRT rates was found between the DAPT and ASA cohorts (p > 0.05, two-sided test).
Conclusions:
In this real-world registry, aspirin (ASA) monotherapy following LAAO was not associated with an increased rate of device-related thrombus (DRT) compared with dual antiplatelet therapy (DAPT) at the 3-month follow-up. These findings support the feasibility and potential safety of ASA monotherapy in selected patients at high risk of bleeding. Further randomized trials are warranted to determine the optimal antiplatelet therapy strategy following LAAO.
