Short summary

Dabigatran is non-inferior to warfarin for the prevention of thromboembolic events in patients with atrial fibrillation. The bleeding risk is not higher in patients receiving dabigatran, but there may be a higher risk of myocardial infarction compared with warfarin treatment. The primary aim of this study is to examine whether dabigatran affects platelet function.

Rationale

Background

Patients with atrial fibrillation have an increased risk of thromboembolic events. Dabigatran is a new oral anticoagulant, which has been shown to be non-inferior to warfarin for the prevention of thromboembolic complications in patients with atrial fibrillation. The risk of bleeding during dabigatran treatment is similar to warfarin treatment. However, the present scientific evidence suggests that the risk of myocardial infarction might be increased among patients treated with dabigatran compared to warfarin. Hence, it is of interest to document whether dabigatran has other effects on haemostasis than inhibition of thrombin. It would be important to know when choosing anticoagulant treatment in selected subgroups, how to correctly interpret blood analyses and determine bleeding risk among patients on dabigatran treatment. In this regard, it is not clear whether dabigatran affects platelet function, but current research suggests that this may be the case. The primary hypothesis is that dabigatran inhibit platelet function, when measured in vitro by stimulation with thrombin.

Purpose

The primary aim of this study is to examine whether dabigatran affects platelet function. Secondary aims are to investigate (I) if dabigatran affects other coagulation tests and (II) how atrial fibrillation affects platelet function.

Description of the cohort

Patients with atrial fibrillation prescribed dabigatran are recruited from the department of Cardiology (B), Odense University Hospital. Healthy volunteers comprise of blood donors from department of Clinical Immunology, Odense University Hospital.

Data and biological material

Healthy persons have one study visit while patients with atrial fibrillation have a baseline visit before starting dabigatran treatment and another visit after 3-6 weeks of treatment with dabigatran. At each visit clinical data are collected by interview and from the patient file: ECG, BMI, smoking status, medication etc.

Blood samples are obtained at baseline from all participants (healthy persons and patients with atrial fibrillation). At the second visit after 3-6 weeks of treatment with dabigatran, patients with atrial fibrillation have blood samples obtained at the time of expected trough-concentration of dabigatran (before a next dose of dabigatran) and at the time of expected peak-concentration of dabigatran (2 hours after a dose of dabigatran).

In the bio bank is kept plasma (Li-heparin, citrate and EDTA) and isolated platelets from each visit.

Collaborating researchers and departments

Department of Clinical Biochemistry and Pharmacology, Odense University Hospital

• PhD-student Pernille Just Vinholt, MD
• Medical Student Anna Söderström
• Chief physician Mads Nybo, MD, PhD

Department of Cardiology, Odense University Hospital

• Chief physician Axel Brandes, MD, PhD