Cerebral Infarction Associated with Free Protein S Deficiency

Kim, Yo Sik; Park, Hyun Young; Cho, Kwang Ho

Abstract

BACKGROUND: Coagulation abnormalities account for 1% to 5% of the causes of adult stroke. The importance of pro-thrombotic condition as a cause of stroke has been the subject of intense controversy. The role of protein S deficiency in the etiology of stroke and the clinical pattern of cerebral infarction caused by the prothrombotic state are still unclear. We investigated clinical characteristics of cerebral infarction caused by free protein S (FPS) deficiency.
METHODS
We enrolled patients with cerebral infarction over 2 years. Cerebral infarction was classified into transient ischemic attack, lacunar infarction, embolic infarction, and thrombotic infarction. We assayed free protein S, prothrom-bin time (PT), and activated partial thromboplastin time (APTT) within 24 hours after stroke and measured free protein S and protein S Ag at 3 months after cerebral infarction. All patients underwent a cardiological examination and neu-roimaging study, and cerebral angiography was done only when necessary.
RESULTS
Eight patients (1.67%) among 474 patients with cerebral infarction had FPS deficiency as a cause of stroke. Four were male and four were female. The history of venous thrombosis was not noted. The age of patients were from 24 to 83 years old at the time of stroke. Two patients had family members with FPS deficiency. The types of stroke were variable, such as thrombotic infarction in 3 patients, lacunar infarction in 4 patients, and embolic infarction in one patient. Cerebral arterial stenosis was noted in 3 patients. Other associated risk factors of stroke were smoking, hypertension, pregnancy, low HDL cholesterol, sinus bradycardia, left ventricular hypertrophy on EKG, and old age. All patients had normal PT, APTT, and liver function test.
CONCLUSIONS
FPS deficiency can be a risk factor for cerebral infarction in young patients as well as old patients. Free protein S (FPS) deficiency may increase risk of cerebral infarction in the presence of other risk factors of stroke but this requires confirmation by a large study in unselected patients.