Impaired brachial artery endothelial function is not predicted by elevatedtriglycerides

OBJECTIVES The purpose of this study was to determine if patients with mode st hyperlipidemia, and no other risk factors for coronary artery disease (C AD), have impaired endothelium-dependent (ED) vasoactivity. BACKGROUND Hypercholesterolemia impairs ED vasodilation, but the impact of elevated triglycerides on endothelial function is not as well established. MEHTODS High-resolution ultrasound was used to determine flow-mediated dila tion (FMD) in the brachial artery (BA) after a 5-min arterial occlusion (en dothelium-dependent stimulus) and nitroglycerin-induced dilation (endotheli um-independent stimulus). We studied 40 healthy controls (Group 1), 38 pati ents with elevated low-density lipoprotein (LDL) cholesterol (Group 2) and 35 patients with elevated triglycerides (Group 3). Patients were excluded i f they had known CAD or other risk factors for CAD, or if they were receivi ng lipid-lowering or vasoactive medications. RESULTS Control patients (Group 1) had normal LDL cholesterol (2.6 +/- 0.8 mmol/liter) and triglyceride levels (1.0 +/-: 0.5 mmol/liter) compared with Group 2 (5.2 +/- 1.2 mmol/liter, 1.8 +/- 0.6 mmol/liter) and Group 3 (3.5 +/- 0.9 mmol/liter, 4.2 +/- 2.5 mmol/liter) subjects (p < 0.001). Baseline BA diameters were the same across the three groups. There was no significan t attenuation of flow mediated vasodilation (FMD) in either of the hyperlip idemic groups (Group 1: 10.9 +/- 5.0% vs. Group 2: 8.6 +/- 6.1% vs. Group 3 : 9.4 +/- 3.9%; p = 0.14). However, nitroglycerin-induced vasodilation was mildly reduced (Group 1: 21.0 +/-: 5.0% vs. 16.9 +/- 7.6% vs. 17.3 +/- 7.7% ; p = 0.01). By multivariate analysis, after controlling for baseline diame ters, only the ratio of LDL/high-density lipoprotein predicted a minor impa irment in FMD. CONCLUSIONS In patients free from other cardiac risk factors, modest elevat ions of triglycerides or LDL cholesterol do not significantly attenuate BA endothelial-dependent vasodilation. Synergism with other cardiac risk facto rs may be required to significantly impair endothelial function in these pa tients. (C) 1999 by the American College of Cardiology.