Shear stress regulation of artery lumen diameter in experimental atherogenesis.

We studied the adaptive response of the arterial wall and intimal thickening under conditions of increased flow in an atherogenic model. Blood flow was increased by construction of an arteriovenous fistula between the right iliac artery and vein in six cynomolgus monkeys fed a diet containing 2% cholesterol and 25% peanut oil. The left iliac artery served as the control. Serum cholesterol increased from 135 +/- 22 mg/dl to 880 +/- 129 mg/dl during the experiment. After 6 months, blood flow in the right iliac artery (420 +/- 95 ml/min) was 10 times greater than in the left iliac artery (44 +/- 9 ml/min, p less than 0.005). Flow velocity in the right iliac artery (31 +/- 6 cm/sec) was more than twofold greater than in the left (12 +/- 1 cm/sec, p less than 0.05). Despite the marked difference in blood flow and flow velocity, calculated wall shear stress was the same in both the right (16 +/- 4 dynes/cm2) and left iliac vessels (15 +/- 2 dynes/cm2) because of a twofold increase in lumen diameter (p less than 0.001) of the right iliac artery. Shear stress in the aorta was also normal (12 +/- 2 dynes/cm2). There was no difference in plaque deposition or mean intimal thickness between the right and left iliac arteries. In the right iliac artery there was a twofold increase in media cross-sectional area (p less than 0.001) but no change in media thickness or total wall thickness. Tangential wall tension and tangential wall stress were two times greater on the right than on the left (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)