The antiphospholipid syndrome: prevalence among patients with stroke and transient ischemic attacks

The prevalence of the antiphospholipid syndrome was determined prospectively in patients presenting with stroke and transient ischemic attacks. An attempt was made to define a subset of stroke patients at risk for this syndrome on the basis of their clinical features.

Fifty-one consecutive patients with stroke and transient ischemic attacks were assessed. Tests used for the laboratory diagnosis of the antiphospholipid syndrome included four phospholipid-dependent coagulation tests for detection of the lupus anticoagulant, and two enzyme-linked immunosorbent assays for antibodies to phospholipid.

Three of 51 patients (6%, 95% confidence intervals 0% to 12.0%) had a lupus anticoagulant and the clinical features of the antiphospholipid syndrome. Seven patients had clinical features suggestive of the syndrome but negative laboratory tests. Those patients who were clinically unlikely to have this syndrome also had negative laboratory tests.

In a series of 51 unselected patients presenting with stroke and transient ischemic attacks, three had the antiphospholipid syndrome. The clinical features of this syndrome are helpful in identifying this group of patients. The role of the lupus anticoagulant in the pathogenesis of stroke remains to be defined.