3.2 LOCAL ARTERIAL STIFFNESS ASSESSED BY ECHO TRACKING IS NOT ASSOCIATED WITH AN INCREASED PULSE WAVE VELOCITY IN HYPERCHOLESTEROLEMIC RABBIT

Abstract

Arterial stiffness (AS) is generally measured by regional arterial pulse wave velocity (rPWV) or locally by arterial distensibility. Although often used interchangeably, some studies show a weak correlation between these well accepted AS index depending on population. Thus, we aim to investigate in an experimental model of hypercholesterolemic rabbit the comparison between arterial pulse wave velocity and local arterial distensibility. Male New Zealand rabbits (8 week-old) received diet with 0.3% cholesterol for 17 weeks. Under anaesthesia, rPWV was measured with catheters between ascending aorta and illiac artery by the foot-to-foot method. Local arterial stiffness was assessed by echotracking with local PWV using the Moens-Korteweg equation = (1.050xD)−1/2, from distensibility as D = ΔA/AxΔP at different sites: carotid (cPWV), aorta (aPWV and femoral (fPWV). Vessel lesions were analysed by fat red staining. Table 1 presents the results. As expected, local PWV is comparable in elastic arteries (carotid and aorta) and higher in muscular arteries (femoral artery). Surprisingly, we observe no modification of rPWV and cPWV between the two groups. However, local aPWV and fPWV are increased in hypercholesterolemic rabbits. Only a correlation between the rPWV and local aPWV was observed in control rabbits (r2=0.76 P = 0.02). Vessel plaques are more important in aorta and femoral artery than in carotid artery. In conclusion, in a rabbit model of atherosclerosis, we observe an increase in local arterial stiffness in aorta and femoral artery associated with plaques. However, this local stiffening seems to have a weak impact on regional PWV. rPWV (m/s) cPWV (m/s) aPWV (m/s) fPWV (m/s) Control 5.0 ± 0.2 6.6 ± 0.4 5.9 ± 0.2 18.8 ± 1.2 Hyperchol 4.9 ± 0.2 6.7 ± 0.4 6.9 ± 0.3 * 25.9 ± 1.8 *