The optimal range of international normalized ratio for radiofrequency catheter ablation of atrial fibrillation during therapeutic anticoagulation with warfarin

Circ Arrhythm Electrophysiol. 2013 Apr;6(2):302-9. doi: 10.1161/CIRCEP.112.000143. Epub 2013 Feb 26.

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.

Methods and 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.

Publication types

  • Comparative Study

MeSH terms

  • Anticoagulants / administration & dosage
  • Anticoagulants / therapeutic use
  • Atrial Fibrillation / blood
  • Atrial Fibrillation / physiopathology
  • Atrial Fibrillation / therapy*
  • Catheter Ablation
  • Dose-Response Relationship, Drug
  • Electrocardiography
  • Female
  • Follow-Up Studies
  • Humans
  • Incidence
  • International Normalized Ratio*
  • Male
  • Middle Aged
  • Postoperative Complications / blood
  • Postoperative Complications / epidemiology
  • Postoperative Complications / prevention & control*
  • Prevalence
  • Retrospective Studies
  • Risk Factors
  • United States / epidemiology
  • Warfarin / administration & dosage*
  • Warfarin / therapeutic use

Substances

  • Anticoagulants
  • Warfarin