Intermediate-Density Lipoproteins and Progression of Carotid Arterial Wall Intima-Media Thickness

Background Although LDL cholesterol (LDL-C) is generally accepted to be a major risk factor for progression of atherosclerosis, the traditional measurement of LDL-C includes measurement of IDL. Little is known about the relationship between IDL and progression of atherosclerosis. Therefore, we investigated the association of plasma lipoprotein subclasses with progression of preintrusive carotid artery atherosclerosis in the Monitored Atherosclerosis Regression Study (MARS). Methods and Results MARS was a randomized, double-blind, placebo-controlled serial arterial imaging trial conducted in subjects 37 to 67 years old with angiographically defined coronary artery disease. Analytical ultracentrifugation was used to determine lipoprotein subclasses, including LDL (Sf 0 to 12), IDL (Sf 12 to 20), VLDL (Sf 20 to 400), and HDL (F1.20 0 to 9) in 188 subjects. Subjects were randomized to a cholesterol-lowering diet plus placebo or lovastatin 80 mg/d. The outcome measure, the annual progression rate of the distal...