Association of atherogenic low-density lipoprotein subfractions with carotid atherosclerosis

Patients with carotid atherosclerosis are at increased risk of both strokeand ischaemic heart disease. Low-density lipoprotein (LDL) is aheterogeneous group of particles, with small, dense particles being moreatherogenic. We studied 79 patients (51 men, mean +/- SD age 62.4 +/- 11.7years) referred for Doppler ultrasound assessment of the carotid arteries.Evidence of carotid atherosclerosis, defined as the presence ofatherosclerotic plaque, stenosis or occlusion in one or more of the sixcarotid artery segments examined, was found in 44 patients (56%). LDLsubfractions were analysed by disc polyacrylamide gel electrophoresis withprior ultracentrifugation of serum to remove chylomicrons. This methodproduces a LDL score; the higher the score, the greater the proportion ofthe more atherogenic LDL subfractions. Mean LDL score was significantlyhigher in diseased patients (mean +/- SD, 1.56 +/- 0.61) than the normalgroup (1.26 +/- 0.65) (t = 2.12, p = 0.037). There was no significantassociation between LDL score and severity of carotid artery stenosis. Age(adjusted odds ratio 1.09, 95% CI 1.03-1.15) and smoking history (2.09, 95%CI 1.10-3.98) predicted carotid atherosclerosis in logistic regressionanalysis, with LDL score achieving borderline significance (2.20, 95% CI0.91-5.29). Small, dense LDL subfractions are associated with carotidatherosclerosis and may be a modifiable risk factor for stroke as well asischaemic heart disease.