The anti-phospholipid syndrome (APS) was first described in 1983. Anti-phospholipid antibodies form a heterogeneous family that can be detected using a number of immunoreactivity assays. Brain ischemic events in patients with anti-phospholipid antibodies can occur in any vascular territory. Anti-phospholipid antibodies are well established as risk factors in a first ischemic stroke, but their role in recurrent stroke is less clear. Cerebral angiography typically demonstrates intracranial branch or trunk occlusion or is normal in about one-third of patients so studied. Echocardiography (primarily two-dimensional, transthoracic) is abnormal in one-third of patients, typically demonstrating nonspecific left-sided valvular (predominantly mitral) lesions, characterized by valve thickening. Recurrent stroke in patients with livedo reticularis (Sneddon's syndrome) has been associated with anti-phospholipid antibodies. Treatment such as platelet antiaggregant and anticoagulant therapy for secondary stroke prevention have both been used in anti-phospholipid antibody syndrome (AAS) and in cerebrovascular disease associated with antiphospholipid antibody immunoreactivity.

Sneddon's syndrome (SS) refers to an infrequent disorder combining skin and ischemic cerebral lesions in patients without a recognizable connective tissue or inflammatory or chronic infectious disease. As a rule, the transient ischemic attacks and strokes are multiple and recurrent in the same or different vascular territories. Both cortical and subcortical areas in the anterior and posterior circulation can be affected, but the most common lesions leading to progressive clinical disability are white matter abnormalities and lacunar infarcts. A large retrospective study on the anti-phospholipid antibody syndrome demonstrated that treatment with high-intensity warfarin (producing an international normalized ratio [INR] of >3) with or without low-dose aspirin (75 mg/day) is significantly more effective than treatment with low-intensity warfarin (producing an INR of <3) with or without treatment with low-dose aspirin or treatment with aspirin alone in preventing further thrombotic events.