Optimal Antithrombotic Regimen in Left Atrial Appendage Occlusion: The Gordian Knot?

Percutaneous left atrial appendage occlusion (LAAO) is an option to reduce the risk of stroke in patients with atrial fibrillation and high bleeding risk. However, device-related thrombosis (DRT) post LAAO is feared as complication. Simard et al. found a very high incidence of DRT compared to other trials. However, antithrombotic regimen and used devices have not been compared between studies. We compared DRT formation, antithrombotic regimen and used device in the recent DRT study, the Amplatzer IDE trial, and the Düsseldorf (DUS) LAAO registry. Occluder thrombosis occurred in 25.3% in the DRT study, 3.8% in the Amulet IDE trial, and 3.3% in the DUS LAAO registry (p < 0.0001). Oral anticoagulation-based regimen was more frequent in the DRT study compared to the DUS LAAO registry, whereas dual antiplatelet regimen was more frequent in the DUS LAAO registry (p < 0.0001). Amplatzer amulet was more frequently used in the DUS LAAO registry as compared to the DRT study (p < 0.0001). DRT is a feared complication after LAAO and seems to be dependent on antiplatelet treatment and underlying device. A clinical study controlling for device and antithrombotic regimen is needed to smash this Gordian knot.