The goal of this clinical randomised controlled trial is to compare two treatment strategies - antiplatelet treatment strategy versus anticoagulation treatment strategy - in patients with acute, ischemic Cervical Artery Dissection (CAD). The study population includes patients presenting with any (clinical or imaging) signs of cerebral ischemia due to CAD.

The trial aims to estimate the net effect of antiplatelet versus anticoagulation treatment strategies on the composite primary outcome including recurrent ischemic stroke, major bleeding, or vascular death at 90 days (±2 weeks) after randomization.

Participants will:

• be randomly allocated to antiplatelet treatment strategy or anticoagulation treatment strategy
• receive treatment according to assigned strategy for the study period of 90 days
• be followed up for 90 days (±2 weeks) after randomization
• undergo clinical assessments to monitor for stroke recurrence, bleeding events, and vascular death Participant reported outcomes will be assessed both at 90 days (±2 weeks) and 12 months (± 4 weeks) after enrolment and will also expand to measures of quality of life and mental health outcomes.

Inclusion Criteria:

• Written informed consent (according to requirements by national legislation)

• Onset/visualization of acute cerebral ischemia (≤ 3 days prior to randomization) attributable to CAD (either)

  • CLINICAL ISCHEMIA: onset of acute ischemic stroke (including retinal infarct) or transient ischemic attack (including amaurosis fugax) attributable to CAD OR
  • ISCHEMIA WITHOUT CORRESPONDING SYMPTOMS: visualization of acute ischemic lesion on diffusion weighted imaging attributable to CAD

• Clinical MRI with suitable sequences for CAD diagnosis

  • available OR
  • scheduled to be performed before discharge (if not performed before enrolment)

• Diagnosis of Cervical Artery Dissection (i.e. extracranial carotid and/or vertebral artery) by MRI/A or CTA based on the presence of the following criteria (at least one)

  • Mural hematoma OR
  • Long tapering stenosis OR
  • Intimal flap OR
  • Double lumen OR
  • Flame-like occlusion of the dissected artery

Exclusion Criteria:

• Contraindications to either antiplatelets or oral anticoagulation therapy
• Other indication than CAD for full dose oral anticoagulation
• Contraindications for performance of MRI
• Age < 18 years
• Female patients who are either pregnant or breastfeeding (pregnancy testing prior to start of treatment will follow the standard operating procedures of clinical routine at participating sites)

Thrombolysis and/or endovascular treatment (EVT) is/are not considered an exclusion criterion.

Open label treatment - blinded endpoint assessor