Apolipoproteins B and AI and the risk of ischemic cerebrovascular events in patients with pre-existing atherothrombotic disease

Background and purpose: The role of blood lipids and lipoprotein-related variables in the prediction of ischemic stroke is less clear than that for coronary heart disease. Apolipoprotein B (Apo B), which reflects the concentration of potentially atherogenic lipoprotein particles, and apolipoprotein AI (Apo A-I), which reflects the corresponding concentration of the anti-atherogenic HDL, represent additional lipoprotein-related variables that may indicate vascular risk. We examined the association between serum concentrations of Apo B, Apo A-I, and the Apo A-I/Apo B ratio and the risk of incident ischemic cerebrovascular events in patients with pre-existing atherothrombotic disease. Methods: Patients with documented chronic coronary heart disease and measured Apo B and Apo A-I concentration, screened for but not included in a clinical trial of lipid modification were followed over 4.8 to 8.1 years for hospitalized incident cerebrovascular events. Results: Among 3,434 patients 266 (7.7%) developed an incident ischemic cerebrovascular event. Adjusting for potential confounders, the hazard ratios (HR) for incident ischemic cerebrovascular events associated with the top versus bottom quartile of Apo B was 1.68 (95%CI, 1.18-2.40), of Apo A-I 0.71 (95%CI, 0.50-1.00), and of Apo A-I/Apo B ratio 0.51 (95%CI, 0.35-0.74). Conclusions: These findings support the hypothesis that Apo B, Apo A-I and the Apo A-I/Apo B ratio predict incident ischemic stroke among patients with preexisting atherothrombotic disease. The potential clinical role of measuring these apolipoproteins for ischemic stroke prediction warrants further study. 0 2008 Elsevier B.V. All rights reserved.