Acute Ischemic Stroke A Case-Control Study

Background and Purpose: Deficiency of free protein S, a naturally occurring anticoagulant, may be acquired in the setting of acute illness and increasingly has become recognized as a possible stroke risk factor. We sought to determine whether free protein S deficiency is associated with acute cerebral infarction among older individuals at risk for stroke. Methods: Free protein S was measured by Laurell rocket immunoelectrophoresis in 94 adults admitted for acute cerebral infarction and in 94 hospitalized control subjects of similar age, sex, and race. Patients with a history of cerebrovascular disease, acute thrombotic or hematologic diseases, or medical conditions known to cause free protein S deficiency were excluded from the control group. Results: The percentage of patients with free protein S deficiency (<20% normal total protein S) was similar in the case and control groups (21% versus 20%, respectively). Among all subjects, free protein S deficiency was more common in blacks than nonblacks (34% versus 13%,p=0.001). A very low free protein S (<15% normal total protein S) was more frequent among case patients than control subjects (11%