Lower diastolic velocity in the internal carotid artery mediates lower cerebral blood flow with age
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Published on: January 19, 2020
John Ashley1,2, Evan P Pasha1,2, Takashi Tarumi1,2,3
1Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, United States.
Insights
Aging increases arterial stiffness, reducing cerebral blood flow (CBF). Higher central arterial stiffness is linked to lower internal carotid artery (ICA) diastolic velocity, which mediates reduced CBF in aging. This impacts brain health.
Area of Science:
- Cardiovascular Physiology
- Neuroscience
- Aging Research
Background:
- Advanced aging is linked to reduced cerebral blood flow (CBF) and increased central arterial stiffness.
- Increased arterial stiffness elevates CBF pulsatility, potentially harming cerebrovascular integrity.
Purpose of the Study:
- To investigate the relationship between central arterial stiffness and CBF parameters (diastolic, systolic, total) in healthy adults.
- To explore the mediating role of arterial stiffness in age-related CBF changes.
Main Methods:
- Utilized color-coded duplex ultrasonography to measure internal carotid artery (ICA) and vertebral artery (VA) pulsatile and total CBF.
- Assessed central artery stiffness using carotid β-stiffness index and carotid-femoral pulse wave velocity (cfPWV).
- Measured cerebral tissue oxygenation via near-infrared spectroscopy (NIRS).
Main Results:
- Total CBF decreased with age (R² = 0.268, P < 0.001).
- ICA diastolic velocity showed negative associations with cfPWV (R² = 0.163, P < 0.001) and carotid β-stiffness index (R² = 0.134, P < 0.001).
- Higher carotid β-stiffness index correlated with lower CBF in aging, mediated by reduced ICA diastolic velocity.
Conclusions:
- Central arterial stiffness contributes to reduced ICA diastolic velocity with age.
- This reduction in diastolic velocity is a key mechanism leading to decreased CBF in aging.
- Findings highlight the significance of age-related arterial stiffening for maintaining brain health and cerebral blood flow.
Abstract:
Advanced aging is characterized by reduced cerebral blood flow (CBF) and increased central arterial stiffness. Increased arterial stiffness is associated with increased CBF pulsatility, which is detrimental to cerebrovascular integrity. We examined the associations between central arterial stiffness, diastolic, systolic, and total CBF in healthy cognitively normal subjects (n = 163, age 20-81 yr, 62% female) who underwent color-coded duplex ultrasonography of the internal carotid (ICA) and the vertebral artery (VA) to measure pulsatile CBF and total CBF. Cerebral tissue oxygenation was measured using near-infrared spectroscopy (NIRS). Carotid β-stiffness index and carotid-femoral pulse wave velocity (cfPWV) were assessed via applanation tonometry and ultrasonography to assess central artery stiffness. Age was negatively associated with total CBF (R2 = 0.268, P < 0.001). ICA diastolic velocity was negatively associated with cfPWV (R2 = 0.163, P < 0.001) and carotid β-stiffness index (R2 = 0.134, P < 0.001). Higher carotid β-stiffness index was associated with lower CBF with age, which was mediated through lower ICA diastolic velocity. These findings suggest that central arterial stiffness with age may lead to reductions in ICA diastolic velocity, contributing to a reduction in CBF.NEW & NOTEWORTHY In this study, we demonstrated that higher central arterial stiffness is associated with lower diastolic velocity of the ICA, which mediates lower CBF with age. These findings provide new mechanistic insights into the reduction in CBF with age and add to the mounting evidence for the importance of age-related central arterial stiffening in brain health.
