Metabolic disorders contribute to subclinical coronary atherosclerosis in patients with coronary calcification

This investigation determined the prevalence of low-density lipoprotein (LD L) subclass distribution abnormalities, elevated lipoprotein(a) (Lp(a)), an d elevated total plasma homocysteine in asymptomatic subjects with subclini cal coronary artery disease determined by electron beam tomography (EBT). F ifty-five percent of subjects were classified as higher risk patients and 4 5% as lower risk patients, employing the National Cholesterol Education Pro gram (NCEP) lipid criteria. EBT was performed in 296 consecutive asymptomat ic subjects, and blood was analyzed for total, LDL, and high-density lipopr otein (HDL) cholesterol, triglycerides, LDL subclass distribution by S-3 gr adient gel electrophoresis, Lp(a), and total homocysteine. Disorders of LDL subclass distribution were the most common disorder with 60.6% of the popu lation expressing a distribution in the small regions IIIa + IIIb of > 20%; and this was more common in the NCEP higher risk group (LDL cholesterol gr eater than or equal to 130 and/or HDL cholesterol < 35 mg/dl) (p <0.0004). A Lp(a) value > 25 mg/dl was found significantly more often in the NCEP hig her (36.9%) compared with lower (14.3%) risk group (p <0.001). None of the laboratory measurements correlated with the calcium score or calcium score percentile rank, with the exception of a weak correlation of mean LDL peak particle diameter and calcium percentile (r = 0.14, p = 0.02). Determinatio n of metabolic disorders in addition to LDL cholesterol and HDL cholesterol increased the diagnostic yield from 55.1%, based on NCEP lipid criteria, t o 84.1% With the addition of LDL subclass distribution, Lp(a), and total ho mocysteine. We conclude that: (1) disorders of LDL subclass distribution an d elevated Lp(a) occur frequently in NCEP higher risk patients with subclin ical coronary artery disease and are the only identifiable disorders in low er NCEP risk patients; and (2) electron beam tomographic evaluation and det ermination of LDL subclass distribution and Lp(a) should be considered for incorporation into primary prevention guidelines. (C) 2001 by Excerpta Medi cal, Inc.