Background: Left atrial appendage closure (LAAC) has emerged as alternative to oral anticoagulation (OAC) for stroke prevention in patients with atrial fibrillation (AF) and contraindication to OAC. Intracardiac thrombus formation related to LAAC device implantation has been described. Device-related thrombi (DRT) can be detected by transesophageal echocardiography (TEE). A routine TEE is recommended after LAAC to assess for complete LAAC and to exclude DRT before cessation of antithrombotic therapy. The value of additional TEE investigations, e.g. in patients at high risk for DRT formation is currently unknown.

Objectives: To evaluate the frequency of DRT during long-term follow-up in a monocentric observational LAAC registry and the status of repetitive TEE investigations on the diagnosis of DRT.

Methods: Consecutive patients undergoing end- and epicardial LAAC were analyzed. A routine TEE investigation 6 to 12 weeks and 12 months after LAAC was recommended to all patients after the procedure. If further TEE investigations for various reasons during the study period (e.g. observation of residual LAA flow, conductance of electrophysiological procedures) were performed, the data was also analyzed. According to the local hospital standard OAC or dual antiplatelet therapy (DAPT) was prescribed after LAAC and ceased if the routine TEE demonstrated absence of residual left atrial appendage perfusion and/or DRT.

Results: A total of 255 patients who underwent the routine TEE investigation were analyzed. 149 patients underwent at least another TEE, 72 patients at least 2 further TEE investigations and 23 4 or more TEE investigations during the study period. The median duration from LAAC to the routine TEE after LAAC was 50 [44; 93] days. Residual LAA flow with minor leakages <5mm was documented in 37 patients (14.5%) and major leakages ³5mm in 7 patients (2.7%). 

DRT was documented in 10 patients (3.9%). Of these patients, DRT was documented in 7 patients (2.7%) at first TEE (<190 days post implantation), in 2 patients in a second TEE (between 179 and 546 days) and in 1 patient in a third TEE (after 788 days) during the study period. Residual flow was found in 3 patients with DRT (1 major leakage, 2 minor leakages).

Patients with DRT were on single antiplatelet therapy (2 patients), dual antiplatelet therapy (6 patients) or oral anticoagulation (2 patients) at the timepoint of DRT documentation. Thrombus resolution was documented in all patients during follow-up after re-initiation or intensification of OAC. Ischemic stroke occurred in 1 patient with DRT.

Conclusions: In this study, DRT was detected in 3.9% after LAAC. Even in patients without early DRT, thrombus formation may occur during long term follow. Our findings indicate that additional TEE investigations should be performed in selected patients with high risk for DRT formation. 

Figure 1 Study overview

LAAC=left atrial appendage closure; TEE=transesophageal echocardiography, DRT=device-related thrombus