Abstract: Objective  To explore the relationship between apolipoprotein, lipoproteinassociated phospholipase A2(LpPLA2) and TOAST ischemic stroke etiology subtypes. Methods  A total of 388 ischemic stroke patients were enrolled as study subjects, and  were classifyied into five groups according to the classical theory TOAST ischemic stroke etiology subtypes：cardiogenic cerebral embolism (CE), largeartery atherosclerosis stroke (LAA), small artery stroke/lacunar infarction (SAO),  the other causes of ischemic stroke (SOE), unexplained ischemic stroke (SUE). Venous blood tests were comducted on all patients on the next morning of the admission day to determine the levels of apolipoprotein A1 (ApoA1), apolipoprotein B (ApoB), apolipoprotein H (Apo H) and plasma phospholipase A2 (LpPLA2) level. Results  There was a significant difference in the exposure rate of hypertension,  diabetes and blood lipid abnormal in the 5 groups(P<0.01); the LpPLA2 and ApoB levels in the LAA group and SAO group were significantly higher than those of CE, SOE and SUE groups(P<0.05); the ApoA1 level in the LAA group and SAO group was significantly lower than those of CE, SOE and SUE groups(P<0.05); whether the patient's stroke etiology subtypes is the LAA, SAO was defined as the dependent variable, age, hypertension, diabetes, alcohol consumption, smoking, dyslipidemia and LpPLA2, ApoA1, ApoB and ApoH level were defined as independent variables, multivariate binary logistic analysis showed that LpPLA2 and ApoB were the risk factors of  LAA and SAO, while Apo a1 was a protective factor. Conclusion  LpPLA2 and ApoB are the incidence risk factors of LAA and SAO, while  ApoA1 whose level undergoing an increase is a protective factor. The level determinations of serum LpPLA2, ApoB and ApoA1 levels are helpful to pinpoint tne TOAST etiological subtypes of ischemic stroke.

Key words: stroke, apolipoproteins, phospholipase A, TOAST etiology subtypes