title: Risk of Ischemic Stroke, Hemorrhagic Stroke, Bleeding, and Death in Patients Switching from Vitamin K Antagonist to Dabigatran after an Ablation.
abstract: BACKGROUND
  Safety regarding switching from vitamin K antagonist (VKA) to dabigatran therapy in post-ablation patients has never been investigated and safety data for this is urgently needed. The objective of this study was to examine if switch from VKA to dabigatran increased the risk of stroke, bleeding, and death in patients after ablation for atrial fibrillation.
  
  
  METHODS
  Through the Danish nationwide registries, patients with non-valvular atrial fibrillation undergoing ablation were identified, in the period between August 22nd 2011 and December 31st 2015. The risk of ischemic stroke, hemorrhagic stroke, bleeding, and death, related to switching from VKA to dabigatran was examined using a multivariable Poisson regression model, where Incidence rate ratios (IRR) were estimated using VKA as reference.
  
  
  RESULTS
  In total, 4,236 patients were included in the study cohort. The minority (n = 470, 11%) switched to dabigatran in the follow up period leaving the majority (n = 3,766, 89%) in VKA treatment. The patients in the dabigatran group were older, were more often males, and had higher CHA2DS2-VASc, and HAS-BLED scores. The incident rates of bleeding and death were almost twice as high in the dabigatran group compared with the VKA group. When adjusting for the individual components included in the CHA2DS2-VASc and HAS-BLED scores, the multivariable Poisson analyses yielded a non-significant IRR (95%CI) of 1.64 (0.72-3.75) for bleeding and of 1.41 (0.66-3.00) for death associated with the dabigatran group, compared to the VKA group. A significant increased risk of bleeding was found in the 110mg bid group with an IRR (95%CI) of 4.49(1.40-14.5).
  
  
  CONCLUSIONS
  Shifting from VKA to dabigatran after ablation was associated with twice as high incidence of bleeding compared to the incidence in patients staying in VKA treatment. The only significant increased risk found in the adjusted analyses was for bleeding with 110mg bid dabigatran and not for 150mg bid. Since there was no dose-response for bleeding, the switch from VKA to dabigatran in itself was not a risk factor for bleeding.
authors: Department of Cardiology, Copenhagen University Hospital Herlev and Gentofte, Copenhagen, Denmark.|Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors: Jannik Langtved
authors: JL
authors: Pallisgaard
authors: Department of Cardiology, Copenhagen University Hospital Herlev and Gentofte, Copenhagen, Denmark.|Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.|The Danish Heart Foundation, Copenhagen, Denmark.|The National Institute of Public Health, University of Southern Denmark, Odense, Denmark.
authors: Gunnar Hilmar
authors: GH
authors: Gislason
authors: Institute of Health, Science and Technology, Aalborg University, Aalborg, Denmark.
authors: Christian
authors: C
authors: Torp-Pedersen
authors: Department of Cardiology, Copenhagen University Hospital Herlev and Gentofte, Copenhagen, Denmark.
authors: Christina Ji-Young
authors: CJ
authors: Lee
authors: Department of Cardiology, Copenhagen University Hospital Herlev and Gentofte, Copenhagen, Denmark.|Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors: Caroline
authors: C
authors: Sindet-Pedersen
authors: Department of Cardiology, Copenhagen University Hospital Herlev and Gentofte, Copenhagen, Denmark.|Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors: Laila
authors: L
authors: Staerk
authors: Department of Cardiology, Copenhagen University Hospital Herlev and Gentofte, Copenhagen, Denmark.
authors: Jonas Bjerring
authors: JB
authors: Olesen
authors: Department of Cardiology, Copenhagen University Hospital Herlev and Gentofte, Copenhagen, Denmark.
authors: Tommi Bo
authors: TB
authors: Lindhardt
mesh_terms: D000368:Aged; D000991:Antithrombins / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000188:drug therapy* / Q000601:surgery; D017115:Catheter Ablation / Q000009:adverse effects* / Q000379:methods; D000069604:Dabigatran / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D003718:Denmark; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019106:Postoperative Hemorrhage / Q000453:epidemiology / Q000209:etiology* / Q000401:mortality; D012042:Registries; D020521:Stroke / Q000453:epidemiology / Q000209:etiology* / Q000401:mortality; D014812:Vitamin K / Q000037:antagonists & inhibitors*
chemical_list: D000991:Antithrombins; D014812:Vitamin K; D000069604:Dabigatran