Left atrial appendage occlusion with prior thrombus under OAC: feasibility and safety in a case series of patients with LA dilation and impaired atrial function

Background Left atrial appendage occlusion (LAAO) is an alternative to prevent stroke in atrial fibrillation (AF) when long-term oral anticoagulation (OAC) is unsuitable. In patients (pts) with atrial cardiomyopathy thrombus formation in the left atrial appendage (TF) occurs more frequently and is traditionally a contraindication to LAAO. An emerging strategy is to seal preexisting TF during device deployment. Device-related thrombus after LAAO and periprocedural risks may be higher with impaired atrial mechanics, underscoring the need for careful surveillance in this high-risk group. Purpose This study evaluates the feasibility and safety of LAAO in pts with prior TF and examines mid-term outcomes in a cohort with atrial dilatation and reduced atrial strain. Methods We retrospectively analyzed 16 pts with LAVI>45ml/m² and reduced atrial strain who underwent LAAO with TF under OAC as indication. If TF was still present, LAAO was only performed when it was located distally within the LAA. All procedures were conducted under continuous transesophageal echocardiography (TOE) guidance. A 3-month clinical follow up including TOE was performed. For preprocedural transthoracic echo 2-plane strain analysis (TOMTEC) was averaged across multiple cardiac cycles. Results Sixteen pts (69.4 ± 10.3y, 50% male) with prior TF (n=12 solid, n=4 in formation) underwent LAAO between 2022 and 2025 (LAmbre [n=6], Watchman [n=5], Amplatzer Amulet [n=4], Lariat [n=1]). Most pts (93.8%) had persistent AF, mean CHA2DS2-VASc score was 3.9 ± 1.8, LAVI 67.7 ± 36.7 mL/m², and LVEF 50.7 ± 11.3% (see table 1). LASr was reduced: 12.4 % ± 8.3 in SR (n=3), 10.6 % ± 4.7 in AF (n=13), reflecting significantly impaired atrial mechanics. At the time of LAAO, all pts were treated with OAC (11 Vitamin K antagonist (VKA), 2 apixaban, 2 rivaroxaban, 1 edoxaban). Despite intensified OAC via agent switch or adherence optimization (Fig. 1), TF persisted or was incompletely resolved in 11 of 16 patients. After LAAO, the same OAC was continued in 13 pts, while in 3, with complete thrombus resolution before the procedure, therapy was switched from VKA to dual antiplatelet therapy (aspirin+clopidogrel). No major periprocedural complications occurred, especially no periprocedural strokes/peripheral embolizations or visual new thrombi were seen in peri-procedural TOE. Follow-up at a mean of 137.8 days revealed no major device-related complications. One patient showed a thrombus attached to the occluder. Minor residual peri-device flow was observed in 6 pts, while all devices remained stable and well positioned. Importantly, there were no thromboembolic events until follow-up. Conclusion LAAO in pts with TF appears to be feasible and safe even in pts with atrial myopathy, with no major procedural complications and especially no peri- or post-procedural thromboembolic events. While long-term follow-up is needed to confirm thromboembolic protection, initial outcomes are encouraging.