775-6 Vascular Remodling and Endothelial Dysfunction in Coronary Disease

Abstract

Early coronary atherosclerosis (CA) is characterized by endothelial dysfunction which is manifested by coronary vasoconstriction in response to the endothelial-dependent vasodilator acetylcholine. The endothelium may be involved in the adaptive process of vascular remodeling (VR). While vascular remodeling has been demonstrated in advanced CA, it is not known if this process occurs early in the course of CA. Thus, this study was designed to test the hypothesis that VR characterized by proximal coronary artery enlargement occurs in patients with angiographically normal or mild CA and abnormal coronary endothelial function. To test this hypothesis, 20 patients found to have normal coronary angiograms or mild CA were studied. Acetylcholine was infused in incremental doses into the left anterior descending (LAD) with angiographic measurement of lumen diameter. Patients were divided into two groups based on their coronary endothelial function. Group 1 demonstrated coronary vasoconstriction in response to acetylcholine and Group 2 had a normal vasodilatory response. Intravascular ultrasound measurements of the proximal LAD diameter and area were made following nitroglycerin. Vessel diameter and area were measured at the internal elastic membrane and indexed to body surface area (BSA). Comparison between the two groups is outlined below:Empty CellGroup 1 (n = 14)Group 2 (n = 6)Vessel Diameter (mm)5.1 ± 0.2*39 ± 0.2Vessel Area (mm2)19.1 ± 1.5*12.4 ± 1.3Vessel Diameter Index (mm/m2)2.6 ± 0.1*2.1 ± 0.1Vessel Area Index (mm2/m2)10.0 ± 0.7*6.6 ± 0.6Data are mean ± SEM*p < 0.02 vs. Group 2 Data are mean ± SEM p < 0.02 vs. Group 2 Five patients in Group 1 and one in Group 2 had ultrasound evidence of mild atherosclerosis. This study demonstrates in vivo that vascular remodeling characterized by enlargement of the proximal coronary arteries occurs early in the course of coronary disease in the presence of endothelial dysfunction.