title: Dabigatran Plasma Levels in Acute Cerebrovascular Events.
abstract: BACKGROUND
  Oral anticoagulation with dabigatran was shown to be effective for stroke prevention in patients with nonvalvular atrial fibrillation without the need for laboratory monitoring. However, a recent publication based on data of the Randomized Evaluation of Long-Term Anticoagulation Therapy study reported that ischemic stroke and bleeding outcomes are correlated with dabigatran plasma concentration (DPC). DPC was determined at a prespecified time point and correlated with cardiovascular events at any time during follow-up. Because of the known variability of DPC, among others depending on renal function, this approach might compromise data evaluation. We report on dabigatran plasma levels in acute cerebrovascular events.
  
  
  METHODS
  Consecutive patients with acute ischemic stroke (AIS) or intracerebral hemorrhage (ICH) while taking dabigatran were retrospectively identified if admission DPC was available. DPC was determined using the diluted thrombin time (Hemoclot (HYPHEN BioMed, Neuville sur Oise, France)). Creatinine clearance (CrCl) was determined by measuring creatinine in plasma and 24-hour urine.
  
  
  RESULTS
  Fifteen AIS and 4 ICH patients were included. Median DPC on admission was significantly higher in ICH patients than in AIS patients (135 ng/mL [interquartile range {IQR} 79-218] and 69.1 ng/mL [IQR 20.6-85.0], respectively; P = .035). Increased CrCl (values above published normal range) was correlated with lower median DPC (60 ng/mL [IQR 10-69] versus 100 ng/mL [IQR 79-157] in patients with normal CrCl, P = .01).
  
  
  CONCLUSIONS
  Higher DPC was found in ICH patients than in AIS patients in temporal proximity to the event. Both decreased and increased renal functions seem to have an important influence on DPC.
authors.affiliation: Neurology Department, University of Erlangen-Nuremberg, Germany. Electronic address: bastian.volbers@uk-erlangen.de.
authors.forename: Bastian
authors.initials: B
authors.lastname: Volbers
authors.affiliation: Neurology Department, University of Erlangen-Nuremberg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Köhrmann
authors.affiliation: Neurology Department, University of Erlangen-Nuremberg, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Kallmünzer
authors.affiliation: Neurology Department, University of Erlangen-Nuremberg, Germany.
authors.forename: Natalia
authors.initials: N
authors.lastname: Kurka
authors.affiliation: Neurology Department, University of Erlangen-Nuremberg, Germany.
authors.forename: Lorenz
authors.initials: L
authors.lastname: Breuer
authors.affiliation: Hemostaseology Department, University of Erlangen-Nuremberg, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Ringwald
authors.affiliation: Neurology Department, University of Erlangen-Nuremberg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Schwab
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003404:Creatinine / Q000097:blood; D000069604:Dabigatran / Q000097:blood*; D005260:Female; D006801:Humans; D020300:Intracranial Hemorrhages / Q000097:blood*; D008297:Male; D012189:Retrospective Studies; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D020521:Stroke / Q000097:blood*
chemical_list: D003404:Creatinine; D000069604:Dabigatran
keywords: Dabigatran; anticoagulant; intracerebral hemorrhage; ischemic stroke; pharmacokinetics; renal function