Association of coronary shear stress with endothelial function and vascular remodeling in patients with normal or mildly diseased coronary arteries.
BACKGROUND
The relationship between coronary remodeling, shear stress and endothelial function remains unclear.


OBJECTIVE
The present study investigated the effects of mechanical factors on structure and function of epicardial coronary arteries.


METHODS
Patients (group 1: %area stenosis<40%, n=55; or group 2: %area stenosis>or=40%, n=17) with a discrete mildly stenotic lesion (%diameter stenosis<30%) underwent intravascular ultrasound examination of the left anterior descending coronary artery for determination of vessel area, lumen area, plaque area, cross-sectional areas at reference segments, and remodeling index (the ratio of vessel area at the culprit lesion to vessel area at the proximal reference site). Further, vascular reactivity was examined using intracoronary administration of acetylcholine, papaverine, and nitroglycerin.


RESULTS
Vessel area significantly correlated with plaque area in both groups (r=0.65, P<0.0001 and r=0.85, P<0.0001). Group 1 showed significantly greater acetylcholine-induced percentage changes in coronary blood flow (67+/-70 vs. 16+/-75%, P<0.05) and coronary artery diameter (-7+/-18 vs.-32+/-31%, P<0.01) and also significantly smaller coronary wall shear stress (65+/-27 vs. 81+/-32 dynes/cm, P<0.05) than group 2. The percentage increase in coronary blood flow induced by acetylcholine was significantly and positively correlated with remodeling index in group 1 (r=0.64, P<0.0001) but not in group 2 (r=-0.03, P=0.90) and was also significantly and positively correlated with coronary wall shear stress in group 1 (r=0.46, P<0.001) but not in group 2 (r=-0.33, P=0.19).


CONCLUSIONS
Endothelium-dependent vasodilation in the resistance coronary artery correlates with remodeling via increased wall shear stress when target lesions %area stenosis is <40%.
Saihara
Keishi
K
Department of Cardiovascular, Respiratory and Metabolic Medicine, Graduate School of Medicine, Kagoshima University, Kagoshima, Japan.
Hamasaki
Shuichi
S
Okui
Hideki
H
Biro
Sadatoshi
S
Ishida
Sanemasa
S
Yoshikawa
Akiko
A
Kataoka
Tetsuro
T
Ninomiya
Yuichi
Y
Mizoguchi
Etsuko
E
Ichiki
Tomoko
T
Otsuji
Yutaka
Y
Tei
Chuwa
C
D000328:Adult; D000368:Aged; D001775:Blood Circulation; D003324:Coronary Artery Disease / Q000473:pathology / Q000503:physiopathology*; D023921:Coronary Stenosis / Q000503:physiopathology*; D003331:Coronary Vessels / Q000473:pathology / Q000503:physiopathology*; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013314:Stress, Mechanical; D014664:Vasodilation; D020257:Ventricular Remodeling / Q000502:physiology*