Stiffness of human arterial wall assessed by intravascular ultrasound.

Little is known about the elastic properties of human arteries. Intravascular ultrasound (IVUS) can measure the instantaneous circumference or diameter of the arteries during a cardiac cycle, and so investigate human arterial elasticity in vivo. We studied 36 patients aged from 35 to 72 years classified into the ischemic heart disease (IHD) group (21 patients aged 39 to 71 years) and the non-ischemic heart disease (NIHD) group (15 patients aged 35 to 76 years) who had no atherogenic factors. The stiffness and wall morphology of six portions from the thoracic descending aorta to common iliac artery were measured by 8F, 15 MHz IVUS. The stiffness parameter, beta, was calculated as 1n (Pmax/Pmin)/(Cmax/Cmin-1), where P is arterial pressure, and C is the circumference of the artery. The thickness of the intima-media complex echo (Th) was used as a substitute for the wall thickness, and Th/D was calculated as an index of relative wall thickness, where D is the minimum luminal diameter. The pulse wave velocity (PWV) was measured with a conventional method. beta increased after branching of the renal artery and increased much more toward the periphery in comparison with the thoracic descending aorta in both groups. At all portions except the abdominal aorta after branching of the renal artery and the common iliac artery, beta was significantly larger in the IHD than the NIHD group. Th/D increased as well as beta in both groups. At all portions except after branching of the renal artery, Th/D was significantly larger in the IHD than the NIHD group.(ABSTRACT TRUNCATED AT 250 WORDS)