Impact of Aging on the Windkessel Function of Carotid Artery

Abstract

Large elastic arteries dampen cyclic mechanical forces of cardiac pulsations by extending and recoiling against intermittent cardiac blood flow ejection. This function (called “Windkessel”) acts to attenuates left ventricular after load, preserves coronary perfusion, and protects vulnerable microvasculature such as the brain. However, the impact of aging on the carotid artery Wind kessel function, especially recoiling ability, is not well known. Therefore, the aim of this study was to characterize carotid artery Windkessel function in healthy individuals across the adult lifespan. Carotid arterial pressure (CAP, via applanationtonometry) and diameter (CAD, via ultrasonography) were simultaneously recorded in 81 participants (age range=29–85 years, 47 women). Carotid arterial systolic blood pressure and beta-stiffness index increased (r=0.390 and r=0.455, P<0.001) and arterial compliance decreased (r=−0.492, P<0.001) with advancing age. Time constant of CAP shortened (r=−0.266, P<0.05), whereas that of CAD extended (r=0.239, P<0.05). The diastolic slope (from the dicrotic notch to the end-diastole) obtained from the pressure-diameter loop was significantly greater than the systolic slope (from systolic foot to the first systolic peak). The systolic and diastolic slopes blunted with aging (r=−0.463 and r=−0.500, P<0.001). In the age-group comparison, there was a significant difference in systolic peak between the first (< 50 years) and third age-group(≥ 70 years), whereas the diastolic peak of the second (50–69 years) and third age-groups were significantly lower than the first age-group. These results suggest that age-related impairment of carotidartery Windkessel function manifests earlier in diastolic recoiling than in systolic expanding. Support or Funding Information This work was supported by JSPS KAKENHI 16KK0011 and 17H02186. Systolic and diastolic slopes obtained from the carotid artery pressure-diameter loop. Data are mean and SD. *P<0.05 vs. < 50 years. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.