The time constant of the cerebral arterial bed: exploring age-related implications

This study assessed differences in τ among healthy volunteers across different age groups. Simultaneous r ecordings of transcranial Doppler cerebral blood flow velocity (CBFV) and arterial blood pressure (ABP) were performed on two groups: young volunteers (below 30 years of age), and older volunteers (above 40 years of age). τ was estimated using mathematical transformation of ABP and CBFV pulse wav eforms. 77 healthy volunteers [52 in the young group, and 25 in the old group] were included. Pulse amplitude of ABP was higher [16.7 (14.6–19.4) mmHg] in older volunteers as compared to younger ones [12.5 (10.9–14.4) mm Hg; p <  0.001]. CBFV was lower in older volunteers [59 (50–66) cm/s] as compared to younger ones [72 (63–78) cm/s p <  0.001].τ was longer in the younger volunteers [217 (168 –237) ms] as compared to the older volunteers [183 (149–211) ms; p = 0.004]. τ significantly decreased with age (rS =  − 0.27; p = 0.018). τ is potentially an integrative marker of the changes occurring in cerebral vasculature, as it encompasses the interplay between changes in compliance and resistance that occur with age.
Source: Journal of Clinical Monitoring and Computing - Category: Information Technology Source Type: research