title: D-dimer levels in combination with clinical risk factors can effectively predict subsequent thromboembolic events in patients with atrial fibrillation during oral anticoagulant therapy.
abstract: OBJECTIVE
  Atrial fibrillation (AF) is associated with hemostatic abnormality and increased risk of thromboembolic events. The aim of the present study was to evaluate whether elevated D-dimer levels in combination with clinical risk factors can adequately predict subsequent thromboembolic events in patients with AF.
  
  
  METHODS
  This was a post hoc analysis of the single-center, prospective observational study. Consecutive patients with nonvalvular AF (245 patients, 74 ± 9 years) treated with warfarin were included. D-dimer levels were measured in combination with clinical risk factors to assess the relationship of this parameter with subsequent thromboembolic events.
  
  
  RESULTS
  D-dimer levels were elevated (≥0.5 μg/ml) in 55 (22%) patients. During an average follow-up time of 756 ± 223 days, 9 (1.8%/year) thromboembolic events occurred. Cox proportional hazard analysis showed that elevated D-dimer levels (hazard ratio, HR, 14.3, p < 0.01) as well as high CHADS₂ score (≥3; HR 9.43, p < 0.01) was associated with thromboembolic events. C-statistic improved to 0.848 from 0.781 when D-dimer level was added to the predictor model based on CHADS₂ score. Elevated D-dimer levels also predicted thromboembolic events in the subgroup of patients with high CHADS₂ score (n = 76, HR 12.1, p = 0.021).
  
  
  CONCLUSIONS
  CHADS₂ scores and D-dimer level can be a useful marker of subsequent thromboembolic events in patients with AF during oral anticoagulant therapy and combination of these can effectively predict thromboembolic events.
authors.affiliation: Division of Cardiology, Ueki Hospital, Kumamoto, Japan. kamefu@rb3.so-net.ne.jp
authors.forename: Tsuneaki
authors.initials: T
authors.lastname: Sadanaga
authors.forename: Shun
authors.initials: S
authors.lastname: Kohsaka
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ogawa
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage*; D001281:Atrial Fibrillation / Q000097:blood / Q000188:drug therapy / Q000453:epidemiology; D015415:Biomarkers / Q000097:blood*; D018572:Disease-Free Survival; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D013923:Thromboembolism / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology
chemical_list: D000925:Anticoagulants; D015415:Biomarkers; D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D