Correlations of serum lipoprotein (a) with ischemic stroke and its etiological subtypes

Objective To investigate the correlation between serum lipoprotein (a) (Lp(a)) level and ischemic stroke and its etiological subtypes. Methods The consecutive inpatients with acute ischemic stroke (case group) and age-and sex-matched healthy subjects (control group) over the same period were enrolled retrospectively. The demographic and baseline clinical data, as well as fasting blood glucose, fibrinogen, homocysteine, total cholesterol, triacylglycerol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and Lp(a) concentration of the case group and the control group were collected. According to TOAST classification criteria, the patients in the case group were divided into large artery atherosclerosis (LAA), small artery occlusion (SAO) and cardioembolism (CE), and the patients with other determined etiology and undetermined etiology were excluded. Multivariate logistic regression analysis was used to make clear the correlation between serum Lp(a) and acute ischemic stroke and its etiological subtypes. Results A total of 214 patients with ischemic stroke were enrolled. Ninety-seven had LAA (45.33%), 64 (29.91%) had SAO, and 53 (24.77%) had CE. There were 118 subjects in the control group. There were significant differences in the proportions of hypertension, diabetes, hyperlipidemia, atrial fibrillation and alcohol consumption, as well as systolic blood pressure, diastolic blood pressure, fasting blood glucose, total cholesterol, low-density lipoprotein cholesterol, Lp(a), fibrinogen, and homocysteine between the case group and the control group (all P<0.001). Multivariate logistic regression analysis showed that after adjustment for age and sex, Lp(a) is an independent risk factor for ischemic stroke (odds ratio [OR] 2.014, 95% confidence interval [CI] 1.273-3.092, P=0.036). The independent risk factors for LAA included hypertension (OR 3.353, 95% CI 1.714-6.558, P=0.001), systolic blood pressure (OR 2.786, 95% CI 1.136-5.538, P=0.016), homocysteine (OR 1.108, 95% CI 1.031-2.191, P=0.005), total cholesterol (OR 2.169, 95% CI 1.599-4.943, P=0.001), low-density lipoprotein cholesterol (OR 2.782, 95% CI 1.093-5.238, P=0.024), and Lp(a) (OR 3.072, 95% CI 1.907-8.064, P=0.001). The independent risk factors for SAO included hypertension (OR 7.042, 95% CI 3.189-25.55, P=0.001), diabetes mellitus (OR 5.162, 95% CI 2.372-11.23, P=0.001), fibrinogen (OR 1.667, 95% CI 1.434-2.025, P=0.045), and homocysteine (OR 1.967, 95% CI 1.859-1.995, P=0.036). The independent risk factors for CE included atrial fibrillation (OR 13.340, 95% CI 4.637-39.20, P=0.001), fibrinogen (OR 2.365, 95% CI 1.147-4.904, P=0.029), and Lp(a) (OR 1.656, 95% CI 1.996-3.001, P=0.035). Conclusions Lp(a) is an independent risk factor for ischemic stroke, and can be used as a serum biomarker for predicting the risk of the onset of ischemic stroke. There are differences in independent risk factors between the different stroke etiological subtypes. Lp(a) is independently associated with LAA and CE; however, it has no independent correlation with SAO. Key words: Stroke; Brain Ischemia; Lipoprotein(a); Atherosclerosis; Heart Diseases; Atrial Fibrillation; Intracranial Embolism; Risk Factors