Management of thrombus formation after electrical isolation of the left atrial appendage in patients with atrial fibrillation

Left atrial appendage (LAA) electrical isolation (LAAEI) in addition to pulmonary vein isolation is an emerging catheter-based therapy to treat symptomatic atrial fibrillation. Previous studies found high incidences of LAA thrombus formation after LAAEI. This study sought to analyse therapeutic strategies aiming at the resolution of LAA thrombi and prevention of thromboembolism.

Left atrial appendage electrical isolation was conducted via creation of left atrial linear lesions or cryoballoon ablation. Follow-up including transoesophageal echocardiography was conducted. In patients with LAA thrombus, oral anticoagulation (OAC) was adjusted until thrombus resolution was documented. Percutaneous LAA closure (LAAC) under use of a cerebral protection device was conducted in case of medically refractory LAA thrombi. Left atrial appendage thrombus was documented in 54 of 239 analysed patients who had undergone LAAEI. Thrombus resolution was documented in 39/51 patients (72.2%) with available follow-up after adjustment of OAC. Twenty-nine patients underwent LAAC and 10 patients were kept on OAC after LAAEI. No thromboembolic events or further LAA thrombi were documented after 553 ± 443 days of follow-up in these patients. Persistent LAA thrombi despite adaption of OAC was documented in 12/51 patients. One patient remained on OAC until the end of follow-up, while LAAC with a cerebral protection device was performed in 11 patients in the presence of LAA thrombus without complications.

Left atrial appendage thrombus formation is common after LAAEI. Adjustment of OAC leads to LAA thrombus resolution in most patients. Left atrial appendage closure in the presence of LAA thrombi might be a feasible option in case of failed medical treatment.