Study Aim and Design:
The primary aim of the CPASS registry is to demonstrate the safety of early anticoagulation with dabigatran following cardioembolic stroke. CPASS is a prospective open label single arm observational study. Safety will be established by demonstrating low rates of hemorrhage in this setting.
Administrative Structure:
CPASS is a Canadian Stroke Consortium led study. The study coordinating centre is at the University of Alberta. Case report forms and data monitoring will be completed electronically, using an online EDC system. All imaging data will be read centrally at the Stroke Imaging Laboratory at the University of Alberta.
Study Design Considerations:
A randomized controlled design was considered (dabigatran versus warfarin). This is considered impractical for a number of reasons. Novel oral anticoagulants are recommended as first line agents for stroke prevention in AF patients by the Canadian Cardiovascular Society.19 These agents are associated with improved safety with respect to bleeding complications. This makes randomization of a patient to warfarin who would otherwise be prescribed dabigatran somewhat ethically dubious. In addition, a randomized design would necessitate a very large study, which would not be completed in a reasonable period of time. A registry design allows us to address the question of safety in a systematic fashion. A safety threshold has been defined for any anticoagulant use early after stroke, based on the rates of warfarin-associated intracranial hemorrhage, which have been reported to be 0.5 to 2.5 per 100 patient years.20-24 The registry design therefore permits determination of whether or not dabigatran is within this threshold. Finally, the systematic collection of clinical and imaging data will allow us to determine any risk factors for hemorrhagic transformation associated with early anticoagulation.
Prescribed Study Treatments:
Patients in whom dabigatran is initiated within 14 days of TIA/stroke symptom onset will be included in the registry. Patients will be treated either at a dose of 110 mg BID or 150 mg BID. The dose and timing of initiation of therapy within that 14 day window will be determined by the treating physician. The factors related to physician choice of initiation time (relative to symptom onset) will be recorded.
Visit Schedule / Clinical Data Collection:
Standard clinical assessments and data will be collected. This will include baseline National Institutes of Health Stroke Scale NIHSS, Glasgow Coma Scale (GCS) and vital signs, which will be recorded in a case report form. Stroke risk factors, past medical history and medications, baseline complete blood count, coagulation profile and renal function tests will also be recorded. CHADS2 and CHADSVaSC scores will also be recorded. Clinical endpoints will be ischemic stroke or intracranial hemorrhage within 30 days of anticoagulant initiation. All cerebral ischemic and intracranial hemorrhagic endpoints will be centrally adjudicated from anonymized clinical records, with the intracranial hemorrhages classified as described above. A data collection form will be filled out for each subject at 30 days post-enrolment indicating clinical status and occurrence of outcome events.
