Is anticoagulant therapy always indicated in "medium-risk" patients with first diagnosed atrial fibrillation? Insights from a real world, 10-year observational study

BACKGROUND: The choice of antithrombotic prophylaxis in the so-called "medium-risk" patients (i.e., CHA2DS2-VASc score = 1 in males or 2 in females) is one of the major enigmatic issues in clinical management of atrial fibrillation (AF). METHODS: We retrospectively evaluated 30-day and 1-year thromboembolic events in all consecutive medium-risk patients visited for first diagnosed AF in the local Emergency Department during a 10-year period. The main aim was to establish whether anticoagulant or antiplatelet therapy was effective to lower the thromboembolic risk in patients receiving these drugs. Bleeding events, related to anticoagulant or antiplatelet therapy, was defined as secondary end point. RESULTS: The final study population consisted of 6389 (3640 males and 2749 females) patients for whom a complete dataset regarding targeted follow-up was available. Patients were then subdivided into two subgroups, according to performance of cardioversion and spontaneous sinus rhythm restoring. In both genders, no significant difference in thromboembolic or bleeding events was noted between patients who underwent cardioversion and were discharged with oral anticoagulant therapy or antiplatelet treatment versus those who were not treated with antithrombotic drugs. Moreover, no difference was also observed in thromboembolic or hemorrhagic event rate between low risk and "medium-risk" patients. CONCLUSIONS: The results of this study suggest that anticoagulant or antiplatelet therapy would not produce clinical benefits in "medium-risk" AF patients.