title: Oral anticoagulation therapy after radiofrequency ablation of atrial fibrillation and the risk of thromboembolism and serious bleeding: long-term follow-up in nationwide cohort of Denmark.
abstract: OBJECTIVE
  To investigate the long-term risk of thromboembolism and serious bleeding associated with oral anticoagulation (OAC) therapy beyond 3 months after radiofrequency ablation (RFA) of atrial fibrillation (AF).
  
  
  RESULTS
  Linking Danish administrative registries, 4050 patients undergoing first-time RFA (2000-11) were identified. Risk of thromboembolism and serious bleeding according to OAC therapy were analysed by incidence rates (presented per 100 person-years) and Cox proportional-hazard models. The median age was 59.5 years (interquartile range, IQR: 52.8-65.2); 26.5% were females. During a median follow-up of 3.4 years (IQR: 2.0-5.6), 71 (1.8%) thromboembolism cases were identified, where incidence rates with and without OAC were 0.56 (0.40-0.78)95%CI and 0.64 (0.46-0.89)95%CI, respectively. Oral anticoagulation discontinuation remained insignificant [hazard ratio 1.42(0.86-2.35)95%CI] in multivariable analysis. Beyond 3 months after RFA 87 (2.1%) serious bleedings occurred; incidence rates with and without OAC were 0.99 (0.77-1.27)95%CI and 0.44 (0.29-0.65)95%CI, respectively. Oral anticoagulation therapy was significantly associated with serious bleeding risk [hazard ratio 2.05(1.25-3.35)95%CI]. In an age- and gender-matched cohort (1 : 4) of 15 848 non-ablated AF patients receiving rhythm-control therapy, thromboembolic rates with and without OAC were 1.34 (1.21-1.49)95%CI and 2.14 (1.98-2.30)95%CI, respectively. Adjusted incidence rate ratio was 0.53 (0.43-0.65)95%CI favouring RFA cohort.
  
  
  CONCLUSIONS
  Thromboembolic risk beyond 3 months after RFA was relatively low compared with a matched non-ablated AF cohort. With cautious interpretation due to low number of events, serious bleeding risk associated with OAC seems to outweigh the benefits of thromboembolic risk reduction. Randomized studies are warranted to test our results.
authors.affiliation: Department of Cardiology, Copenhagen University Hospital Gentofte, Niels Andersens Vej 65, Hellerup 2900, Denmark dkarasoy@gmail.com.
authors.forename: Deniz
authors.initials: D
authors.lastname: Karasoy
authors.affiliation: Department of Cardiology, Copenhagen University Hospital Gentofte, Niels Andersens Vej 65, Hellerup 2900, Denmark National Institute of Public Health, University of Southern Denmark, Copenhagen, Denmark.
authors.forename: Gunnar Hilmar
authors.initials: GH
authors.lastname: Gislason
authors.affiliation: Department of Cardiology, Copenhagen University Hospital Gentofte, Niels Andersens Vej 65, Hellerup 2900, Denmark.
authors.forename: Jim
authors.initials: J
authors.lastname: Hansen
authors.affiliation: Department of Cardiology, Copenhagen University Hospital Gentofte, Niels Andersens Vej 65, Hellerup 2900, Denmark.
authors.forename: Arne
authors.initials: A
authors.lastname: Johannessen
authors.affiliation: Department of Cardiology, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
authors.forename: Lars
authors.initials: L
authors.lastname: Køber
authors.affiliation: Department of Cardiology, Copenhagen University Hospital Gentofte, Niels Andersens Vej 65, Hellerup 2900, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Hvidtfeldt
authors.affiliation: Department of Cardiology, Copenhagen University Hospital Gentofte, Niels Andersens Vej 65, Hellerup 2900, Denmark.
authors.forename: Cengiz
authors.initials: C
authors.lastname: Özcan
authors.affiliation: Department of Cardiology, Copenhagen University Hospital Gentofte, Niels Andersens Vej 65, Hellerup 2900, Denmark Institutes of Health, Science and Technology, Aalborg University, Aalborg, Denmark.
authors.forename: Christian
authors.initials: C
authors.lastname: Torp-Pedersen
authors.affiliation: Department of Cardiology, Copenhagen University Hospital Gentofte, Niels Andersens Vej 65, Hellerup 2900, Denmark.
authors.forename: Morten Lock
authors.initials: ML
authors.lastname: Hansen
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000453:epidemiology / Q000601:surgery*; D017115:Catheter Ablation; D003131:Combined Modality Therapy; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006470:Hemorrhage / Q000139:chemically induced* / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D013923:Thromboembolism / Q000453:epidemiology / Q000517:prevention & control*
chemical_list: D000925:Anticoagulants
keywords: Atrial fibrillation; Bleeding; Oral anticoagulation; Radiofrequency ablation; Risk; Thrombosis