Clinical Research Directory

Inclusion Criteria: 1. Patients of at least 18 years of age with confirmed antiphospholipid syndrome according to Sydney criteria and with first or recurrent arterial thrombotic manifestation, including those with asymptomatic brain infarcts on diagnostic imaging. 2. Treatment with either A) a vitamin K antagonist (VKA) with therapeutic range, international normalized ratio (INR) 2.0-3.0 plus low-dose aspirin (75-100 mg daily), B) a VKA alone with therapeutic range, INR 2.0-3.0 or C) VKA with therapeutic range, INR 3.0-4.0, or D) with a dual antiplatelet regimen, if considered appropriate by the treating physician. 3. Signed informed consent obtained (in jurisdictions where required). Exclusion Criteria: 1. Inability to follow the patient due to geographical or other reasons. 2. Patients with documented poor compliance. 3. Bleeding risk that in the opinion of the treating physician makes combination antithrombotic therapy unsafe. 4. Pregnancy or planned pregnancy. 5. Venous thrombotic event diagnosed after the last arterial event.