HEMODYNAMICS OF ENDOVASCULAR PROSTHESES

A surgical study (Bergeron et al., 1991, International Angiology 10(3) , 182-186) picked out that re-endothelialization of implanted expandab le stents, frequently used to reduce the recurrent stenosis rate after balloon angioplasty, was correct and more rapid in femoro-popliteal a rteries (quasi-straight vessels) than in iliac arteries (bifurcated ve ssels). Since it is now well known that local hemodynamics are conside red to be an important atherogenic factor, we decided to compare and o ptimize the shape of the existing equipments, in order to further give some informations to surgeons about the optimal stenting at the site of bifurcation. Therefore, we studied in vitro (1) the influence of th e protruding part of a stent on the flow patterns in the branches of a n aorto-iliac bifurcation model, and (2) the possibility of reducing o r preventing this impact. Qualitative information was obtained from vi sualizations in the horizontal median plane of the bifurcation model, while Doppler ultrasonic velocimetry provided quantitative data, at di fferent points of the cardiac cycle. Results showed that a standard st ent implanted in a daughter branch of the bifurcation may have a consi derable influence on flow behaviour when it is sticking out of the dau gther branch. A new design of stent, with a bevelled shape, showed a s ignificant reduction of flow disturbance. (C) 1998 Elsevier Science Lt d. All rights reserved.