title: Relationship of activated partial thromboplastin time to coronary events and bleeding in patients with acute coronary syndromes who receive heparin.
abstract: BACKGROUND
  Antithrombotic therapy with intravenous heparin in conjunction with aspirin reduces negative cardiovascular (CV) outcomes in patients with acute coronary syndromes. The need for a therapeutic range with the activated partial thromboplastin time (APTT) has not been validated in patients with arterial thrombosis who receive heparin. Therefore, it is unclear whether there is an association between recurrent CV events and low APTT values and between bleeding and high APTT values.
  
  
  RESULTS
  We examined the relationship between the APTT and recurrent cardiovascular events and bleeding among 5058 patients with an acute coronary syndrome without ST elevation who received intravenous heparin in the OASIS-2 trial. The increase in relative risk of recurrent CV events was 1.54 (95% CI 1.10 to 2.15; P=0.01) among patients with APTT values <60 seconds compared with patients with APTT values > or =60 seconds. When patients had persistently subtherapeutic APTT values for more than 48 hours, the increase in relative risk of a recurrent CV event was 1.84 (95% CI 1.25 to 2.70). Higher APTT values were associated with bleeding; for every 10-second increase in the APTT, the probability of major bleeding was increased by 7% (95% CI 3% to 11%; P=0.0004).
  
  
  CONCLUSIONS
  In patients with acute coronary syndromes without ST elevation who are treated with intravenous heparin, our findings justify regular APTT monitoring to minimize recurrent ischemic events and bleeding.
authors.affiliation: McMaster Clinic-Population Health Section, 237 Barton St E, Hamilton, Ontario L8L 2X2, Canada. anands@mcmaster.ca
authors.forename: Sonia S
authors.initials: SS
authors.lastname: Anand
authors.forename: Salim
authors.initials: S
authors.lastname: Yusuf
authors.forename: Janice
authors.initials: J
authors.lastname: Pogue
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Ginsberg
authors.forename: Jack
authors.initials: J
authors.lastname: Hirsh
mesh_terms: D000208:Acute Disease; D000925:Anticoagulants / Q000008:administration & dosage / Q000009:adverse effects*; D001241:Aspirin / Q000008:administration & dosage; D003327:Coronary Disease / Q000097:blood* / Q000188:drug therapy / Q000517:prevention & control; D005260:Female; D006470:Hemorrhage / Q000139:chemically induced* / Q000517:prevention & control; D006493:Heparin / Q000008:administration & dosage / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015337:Multicenter Studies as Topic / Q000706:statistics & numerical data; D010314:Partial Thromboplastin Time; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage; D011237:Predictive Value of Tests; D016032:Randomized Controlled Trials as Topic / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D012306:Risk; D055502:Secondary Prevention; D016896:Treatment Outcome
chemical_list: D000925:Anticoagulants; D010975:Platelet Aggregation Inhibitors; D006493:Heparin; D001241:Aspirin