title: The optimal range of international normalized ratio for radiofrequency catheter ablation of atrial fibrillation during therapeutic anticoagulation with warfarin.
abstract: BACKGROUND
  Uninterrupted anticoagulation with warfarin during radiofrequency catheter ablation (RFA) of atrial fibrillation is associated with a lower risk of periprocedural complications than when warfarin is temporarily discontinued. However, the optimal international normalized ratio (INR) levels during RFA have not been defined.
  
  
  RESULTS
  In this retrospective analysis, RFA was performed in 1133 consecutive patients (mean age, 61±10 years) with paroxysmal (550) or persistent atrial fibrillation (583). Patients were grouped based on the INR on the day of RFA. There was a quadratic relationship between the INR and bleeding and vascular complications (P<0.001). Complications were less prevalent when INR was ≥2.0 and ≤3.0 (5% [31/572]) than when INR was <2.0 (10% [49/485]; P=0.004) and >3.0 (12% [9/76]; P=0.03). The prevalence of pericardial tamponade (1%) was similar at all INRs. From the quadratic model, the optimal range of INR was calculated as 2.1 to 2.5. INRs<2.0 and >3.0 were associated with a >2-fold increase in complications, with a further steep rise beyond an INR>3.5. Concomitant clopidogrel use was associated with a significant increase in complications at all INRs (odds ratio=3.1; ±95% confidence interval, 1.4-7.4). Unfractionated heparin requirements to maintain a therapeutic activated clotting time during RFA was reduced by 50% in patients with an INR>2.0.
  
  
  CONCLUSIONS
  The optimal INR range during uninterrupted periprocedural anticoagulation using warfarin is narrow. Therefore, INR levels should be carefully monitored in preparation for RFA of atrial fibrillation.
authors: Cardiovascular Medicine, University of Michigan, Ann Arbor, MI, USA.
authors: Jin-Seok
authors: JS
authors: Kim
authors: Krit
authors: K
authors: Jongnarangsin
authors: Rakesh
authors: R
authors: Latchamsetty
authors: Aman
authors: A
authors: Chugh
authors: Hamid
authors: H
authors: Ghanbari
authors: Thomas
authors: T
authors: Crawford
authors: Miki
authors: M
authors: Yokokawa
authors: Eric
authors: E
authors: Good
authors: Frank
authors: F
authors: Bogun
authors: Frank
authors: F
authors: Pelosi
authors: Fred
authors: F
authors: Morady
authors: Hakan
authors: H
authors: Oral
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000097:blood / Q000503:physiopathology / Q000628:therapy*; D017115:Catheter Ablation; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000097:blood / Q000453:epidemiology / Q000517:prevention & control*; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D014859:Warfarin / Q000008:administration & dosage* / Q000627:therapeutic use
chemical_list: D000925:Anticoagulants; D014859:Warfarin