SAfety of Fondaparinux in transoesophageal echocardiography-guided Electric cardioversion of Atrial Fibrillation (SAFE-AF) study: A pilot study

Summary Background Current guidelines recommend unfractionated heparin (UFH) or low-molecular-weight heparin plus an oral anticoagulant for the prevention of thromboembolism in patients undergoing electric cardioversion of atrial fibrillation (AF). Selective factor Xa inhibitors, such as fondaparinux, which has a favourable benefit-risk profile in the prevention and treatment of venous thromboembolism and the management of acute coronary syndromes, have not been systematically evaluated in this setting. Aim To evaluate the efficacy and safety of fondaparinux versus standard treatment in patients undergoing echocardiographically-guided cardioversion of AF. Methods In this multicentre, randomized, open-label, controlled, two-parallel-group, phase II pilot study, patients with AF undergoing electric cardioversion following transoesophageal echocardiography (TEE) were randomized to fondaparinux or standard therapy (UFH plus vitamin K antagonist [VKA]). Patients showing an atrial thrombus in the first TEE (clot-positive) were randomized to treatment with fondaparinux or standard care for 4 weeks before cardioversion. Results The primary endpoint (combined rate of cerebral neurological events, systemic thromboembolism, all-cause death and major bleeding events) occurred in 3 of 174 (1.7%) patients on fondaparinux and 2 of 170 (1.2%) patients on UFH + VKA. The rate of thrombus disappearance among clot-positive patients was higher in the fondaparinux arm (11 of 14; 78.6%) than in the UFH + VKA arm (7 of 14; 50.0%). Incidences of adverse events were similar (45.4% with fondaparinux and 46.5% with UFH + VKA). Conclusion In this pilot study in patients with TEE-guided cardioversion, the use of fondaparinux appeared to be well tolerated, with similar efficacy to UFH + VKA. Furthermore, a trend to greater thrombus resolution was observed.