ASSOCIATION OF REMNANT LIPOPROTEIN LEVELS WITH IMPAIRMENT OF ENDOTHELIUM-DEPENDENT VASOMOTOR FUNCTION IN HUMAN CORONARY-ARTERIES

Background-It remains undetermined whether triglyceride-rich lipoprote ins are an independent risk factor for atherosclerosis. Methods and Re sults-The correlation of responses of coronary arterial diameter (quan titative coronary angiography) and coronary blood flow (intracoronary flow wire technique) to intracoronary infusion of acetylcholine (10 an d 50 mu g/min) with coronary risk factors including remnant lipoprotei n levels was statistically analyzed in 106 consecutive subjects with n ormal coronary angiograms. Remnant Lipoproteins were isolated from fas ting blood with an immunoaffinity mixed gel containing anti-apolipopro tein (apo) A-1 and anti-apoB-100 monoclonal antibodies. In multivariat e stepwise regression analysis, remnant lipoprotein levels had the mos t significant correlation with. abnormal epicardial coronary vasomotor responses to acetylcholine infusion, reflected by impaired dilation o r constriction of the epicardial coronary arteries, and the levels als o had an inverse and independent correlation with the coronary blood f low increase in response to acetylcholine. In a subgroup of 53 consecu tive subjects, constrictor responses of epicardial coronary diameters to intracoronary infusion of N-G-monomethyl-L-arginine (50 mu mol/min for 4 minutes) at baseline, reflecting the presence of coronary nitric oxide bioactivity, had an inverse and independent correlation with re mnant lipoprotein levels by use of multivariate analysis. Conclusions- Remnant lipoprotein levels were independently associated with abnormal endothelium-dependent vasomotor function in large and resistance coro nary arteries in humans, indicating that remnant Lipoproteins may impa ir endothelial vasomotor function in human coronary arteries. The decr ease in coronary nitric oxide bioactivity may be responsible in part f or the inhibitory effects of remnant lipoproteins.