The Comparative Effectiveness and Safety of Different Anticoagulation Strategies for Treatment of Left Atrial Appendage Thrombus in the Setting of Chronic Anticoagulation for Atrial Fibrillation or Flutter

PURPOSE: To compare effectiveness of different treatments for atrial fibrillation (AF) patients who were scheduled for cardioversion (CV) or ablation (CA) presenting with left atrium appendage (LAA) thrombus despite chronic oral anticoagulation therapy (OAC). METHODS: This was a retrospective cohort study. We analyzed 2014–2019 medical records of patients scheduled for CV or CA of AF who were diagnosed with LAA thrombus despite optimal OAC and had a follow-up transesophageal echocardiogram (TOE). Changes in treatment were divided into the following groups: switch to a drug with different mechanism of action, switch to a drug with similar mechanism of action, initiation of combination therapy, or deliberate no change in treatment. Patients with contraindications to non-vitamin K antagonists were excluded from the analysis. RESULTS: We analyzed data of 129 patients comprising 181 cycles of treatment. The overall effectiveness of LAA thrombus dissolution was 51.9% regardless of the number of cycles and 42.6% for the first cycle of treatment. Any change of treatment was more effective than deliberate no change—OR 2.97 [95% CI: 1.07–8.25], P = 0.031, but no particular strategy seemed to be more effective than the other. Left atrium area (OR 0.908 [95% CI: 0.842–0.979]) and number of treatment cycles (OR 0.457 [95% CI: 0.239–0.872]) were both adversely related to thrombus resolution. There was one ischemic and three bleeding adverse events during the treatment. CONCLUSION: LAA thrombus resolution in patients already on OAC may require a change of previous OAC treatment but the overall effectiveness of dissolution seems to be about 50%. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10557-021-07278-9.