Is the presence of hyperlipidemia associated with impairment of endothelium-dependent neointimal relaxation after percutaneous transluminal coronary angioplasty?

To determine whether hyperlipidemia affects the endothelium-dependent vasomotor response along the dilated vessel after percutaneous transluminal coronary angioplasty (PTCA), we evaluated 32 patients with one-vessel disease, 3-6 months after successful PTCA without restenosis. Fourteen patients had mild stenotic lesions not subjected to PTCA (non-PTCA sites) in addition to the PTCA sites. Vessel diameter changes at 32 PTCA and 36 non-PTCA sites were assessed by quantitative angiography, before and after intracoronary injection of acetylcholine (20 micrograms to the right and 50 micrograms to the left coronary artery) and of nitroglycerin (0.1-0.3 mg). The acetylcholine response ranged from 46% (dilation) to -100% (constriction). All coronary arteries were dilated in response to nitroglycerin, which suggested preservation of the function of vascular smooth muscle, and the presence of an abnormality in endothelial function in those patients with a constrictor response to acetylcholine. There was a negative correlation between the acetylcholine response and the serum total cholesterol level at PTCA sites (r = -0.37; P = 0.038) and at non-PTCA sites (r = -0.46; P = 0.005). These findings indicate that hyperlipidemia is associated with a loss of endothelium-dependent vasodilation, not only at non-PTCA but also at PTCA sites, at which restoration of endothelial function might have occurred. They also suggest that hyperlipidemia may be related to the functional state of the regenerated endothelium at sites where PTCA had been previously performed.