Purpose: Increase in arterial stiffness could increase the transmission of pulsatile flow energy and potentially damage the downstream microcirculation. The study of changes in the microcirculatory pulsatility could help to improve our understanding on the deleterious effect of the upstream arterial stiffness. To achieve this goal, we studied the relationship between aortic stiffness, local stiffness (β indice) and distensibility (Ep) of carotid and a local microcirculatory pulsatility index (μFP).

Methods: Aortic stiffness was determined from the carotid-femoral pulse wave velocity (PWV) measured by tonometry (Pulse Pen). Carotid stiffness was measured by echotracking (e-tracking, Aloka) and forearm skin blood flow was recorded by laser Doppler flowmetry (LDF). Data were recorded in subjects (n=17, 15 men, mean age 45±SD8 years) without hypertension, diabetes or obesity. The μFP index was calculated as: (LDF max – LDF min) / mean LDF over 35 cardiac cycles.

Results: A significant positive correlation was found between PWV, μFP and age (R²= 0.42, p<0.01 - R²= 0.32, p<0.05) and between PWV and the μFP index (R²= 0.32, p<0.05 adjusted by age). No significant correlation was found between β stiffness indice (R² = 0.0002), Ep (R²=0.03) and μFP.

Conclusion: Our data show that the pulsatility of the microvascular flow, an easily determined indice, is highly correlated to the aortic stiffness but not to medium-sized artery. These preliminary data have important implication for the further understanding of the deleterious effects of the segmental arterial stiffness on the end-organ microvasculature.