IN-VIVO CHARACTERIZATION OF SEGMENTAL ELASTIC PROPERTIES OF THE AORTIC TREE BY INTRAVASCULAR ULTRASOUND

Background: The measurement of pulse pressure, combined with offline p lanimetric measurement of segmental changes in luminal dimensions duri ng one heart cycle, allows calculation of arterial elastic properties. The aim of this study was to construct an elastic profile along the a ortic tree in normotensive patients undergoing diagnostic cardiac cath eterization. Methods: Local elastic properties were determined at the thoracic aorta, abdominal aorta, aortic bifurcation, common iliac arte ry, and external iliac artery by measuring pulse pressure in combinati on with direct measurement of segmental changes in the free lumen area by means of intravascular ultrasound images.Results: Arterial elastic ity decreased with increasing distance from the heart. Compliance decr eased from 1.27 +/- 0.16 x 10(-10) m5/N at the descending aorta to 0.0 76 +/- 0.007 x 10(-10) m5/N at the external ilia artery. The aortic bi furcation showed the highest pulse wave velocity (9.83 +/- 0.60 m/s at the aortic bifurcation vs 9.24 +/- 0.48 m/s at the common iliac arter y). Conclusions: The intravascular ultrasound method described not onl y provides information about morphologic structure of the vessel wall, it also allows determination of local mechanical properties. Using in travascular ultrasound measuring techniques, it was possible to establ ish an elasticity profile of large arteries in vivo.