Endothelial Dysfunction in Patients with Essential Hypertension

Doo, Young Cheoul; Rim, Chong Yun; Lee, Jae Myung; Koh, Soon Hee; Han, Kyoo Rok; Oh, Dong Jin; Ryu, Kyu Hyung; Koh, Young Bahk; Lee, Young

Abstract

BACKGROUND
The endothelium is an important regulator of vascular tone via release of relaxing and constricting substances. The regulatory effect of the endothelium has been shown to be impaired in atherosclerotic arteries in human and animal models of hypertension. But there are some debates on extent and developing time of endothelium dysfunction in patients with hypertension, and the determining factors for endothelium dysfunction also were not defined. The objects of this study are to determine whether endothelial function is impaired in coronary and peripheral arteries, and to investigate the predicting factors for endothelial dysfunction in patients with essential hypertension.
METHODS
The study patients comprised 14 patients with essential hypertension(M : 7, Mean age : 50+/-2 year) and 6 normal control (M :2, Mean age : 45+/-4 year). We assessed the vasomotor response to acetylcholine and nitroglycerin by change of arterial diameter during the infusion of acetylcholine, from 10(-9M) to 10(-6M) in coronary artery and 7.5, 15, and 25ug/min in left superficial femoral artery, and on intracoronary injection of 200ug nitroglycerin after acetylcholine infusion.
RESULTS
1) There were no significant differences in sex, age, body mass index and ventricular mass index, except systolic(174+/-5 vs 118+/-7mmHg, p<0.001) and distolic blood pressure(106+/-5 vs 75+/-5mmHg,p<0.001) between patients with hypertension and normal control. 2) There were no significant differences in laboratory date of total cholesterol, HDL-cho-lesterol, lipoprotein(a), microaluminuria and von-Willebrand Factor but Fibrinogen level was raised significantly in patients with hypertension than normal control(299+/-26 vs 192+/-23ng/dl, p=0.04). 3) The vasoconstrictor response to acetylcholine, 10-8 to 10-6 M concentration, at proximal, mid, and distal left anterior descending coronary artery were increased significantly in hypertensive patients than normal control(p<0.05). At rest superficial femoral artery, the vasodilator response to acetylcholine, only 25ug/min, was decreased in patients with hypertension(p<0.05). There was no signficant difference in the vasodilator response to nitroglycerin at coronary artery between two groups but in superficial femoral artery, the vasodilator response to nitroglycerin was decreased significantly in hypertensive patients(p<0.05).
CONCLUSIONS
The results of this study suggest that endothelium dependent vascular relaxation is impaired in both coronary and superificial femoral artery and it remained to be investigated the predicting factors for endothelial dysfunction in patients with essential hypertension.