title: Risk of intracerebral hemorrhage in patients with arterial versus cardiac origin of cerebral ischemia on aspirin or placebo: analysis of individual patient data from 9 trials.
abstract: OBJECTIVE
  Patients who are anticoagulated after cerebral ischemia have a 19-fold-higher risk of intracerebral hemorrhage (ICH) if they had an arterial rather than a cardiac source. To determine whether this excess risk of ICH was due to the underlying disease (cerebral ischemia of arterial versus cardiac origin) or whether it depended on the antithrombotic regimen, we studied the risk of ICH in arterial versus cardiac origin of cerebral ischemia in patients who received aspirin or no antithrombotic drugs.
  
  
  METHODS
  Individual patient data of patients who received aspirin or placebo after cerebral ischemia were obtained from 9 clinical trials. Presence of atrial fibrillation was considered evidence of a cardiac source. Otherwise, events were considered of arterial origin. Cox proportional-hazards modeling was used for univariate and multivariate analyses.
  
  
  RESULTS
  Fifty-four ICHs occurred in 16 625 patient-years in the aspirin-treated patients, and 7 ICHs occurred in 4317 patient-years in those on placebo. After multivariate adjustment for age, sex, current smoking, history of hypertension and diabetes, and aspirin dose (aspirin-treated patients only), the hazard ratio for ICH in patients with an arterial versus a cardiac source was 0.74 (95% confidence interval, 0.30 to 1.82) for aspirin-treated patients and 4.34 (95% confidence interval, 0.35 to 54) for placebo-randomized patients.
  
  
  CONCLUSIONS
  Our findings do not confirm the previous finding of an excess risk of ICH in patients with cerebral ischemia of arterial origin. Therefore, it seems that having cerebral ischemia of arterial origin by itself is not associated with an increased risk of ICH, but only in combination with high-intensity anticoagulation.
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: M J
authors.initials: MJ
authors.lastname: Ariesen
authors.forename: A
authors.initials: A
authors.lastname: Algra
authors.forename: P J
authors.initials: PJ
authors.lastname: Koudstaal
authors.forename: P M
authors.initials: PM
authors.lastname: Rothwell
authors.forename: C
authors.initials: C
authors.lastname: van Walraven
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects / Q000627:therapeutic use; D001157:Arterial Occlusive Diseases / Q000453:epidemiology*; D001241:Aspirin / Q000009:adverse effects* / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000453:epidemiology*; D002545:Brain Ischemia / Q000188:drug therapy* / Q000453:epidemiology; D015984:Causality; D002543:Cerebral Hemorrhage / Q000139:chemically induced* / Q000453:epidemiology; D015897:Comorbidity; D006801:Humans; D015999:Multivariate Analysis; D016017:Odds Ratio; D016016:Proportional Hazards Models; D016032:Randomized Controlled Trials as Topic / Q000706:statistics & numerical data; D018570:Risk Assessment
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D001241:Aspirin