title: Warfarin and fibrinolysis--a challenging combination: an observational cohort study.
abstract: BACKGROUND
  Patients presenting with ST-segment elevation myocardial infarction (STEMI) frequently use warfarin. Fibrinolytic agents and warfarin both increase bleeding risk, but only a few studies have been published concerning the bleeding risk of warfarin-prescribed patients receiving fibrinolysis. The objective of this study was to define the prevalence for intracranial haemorrhage (ICH) or major bleeding in patients on warfarin treatment receiving pre-hospital fibrinolysis.
  
  
  METHODS
  This was an observational cohort study. Data for this retrospective case series were collected in Helsinki Emergency Medical Service catchment area from 1.1.1997 to 30.6.2010. All warfarin patients with suspected ST-segment elevation myocardial infarction (STEMI), who received pre-hospital fibrinolysis, were included. Bleeding complications were detected from Medical Records and classified as ICH, major or minor bleeding.
  
  
  RESULTS
  Thirty-six warfarin patients received fibrinolysis during the study period. Fourteen patients had bleeding complications. One (3%, 95% CI 0-15%) patient had ICH, six (17%, 95% CI 7-32%) had major and seven (19%, 95% CI 9-35%) had minor bleeding. The only fatal bleeding occurred in a patient with ICH. Patients' age, fibrinolytic agent used or aspirin use did not predispose to bleeding complications. High International Normalized Ratio (INR) seemed to predispose to bleedings with values over 3, but no statistically significant difference was found.
  
  
  CONCLUSIONS
  Bleedings occur frequently in warfarin patients treated with fibrinolysis in the real world setting, but they are rarely fatal.
authors.affiliation: Helsinki Emergency Medical Service System, Helsinki University Central Hospital, PL 112, 00099 Helsinki City, Helsinki, Finland. sini.saarinen@hus.fi
authors.forename: Sini
authors.initials: S
authors.lastname: Saarinen
authors.forename: Jyrki
authors.initials: J
authors.lastname: Puolakka
authors.forename: James
authors.initials: J
authors.lastname: Boyd
authors.forename: Taneli
authors.initials: T
authors.lastname: Väyrynen
authors.forename: Harri
authors.initials: H
authors.lastname: Luurila
authors.forename: Markku
authors.initials: M
authors.lastname: Kuisma
mesh_terms: D000368:Aged; D015331:Cohort Studies; D004359:Drug Therapy, Combination / Q000009:adverse effects*; D005260:Female; D005342:Fibrinolysis; D005387:Finland / Q000453:epidemiology; D006801:Humans; D020300:Intracranial Hemorrhages / Q000453:epidemiology*; D008297:Male; D008485:Medical Audit; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy; D012189:Retrospective Studies; D014859:Warfarin / Q000009:adverse effects / Q000627:therapeutic use*
chemical_list: D014859:Warfarin