Revisiting the Relationship between Pulse Transit Time and Arterial Stiffness

Arterial stiffness is a known risk factor for cardiovascular events and is often assessed using pulse transit time, but this measure is strongly influenced by short-term changes in blood pressure. In this study, pulse transit time and arterial blood pressure were analyzed in 93 adults to examine their relationship to arterial stiffness. The results showed that the physiological stiffness measure was independent of systolic blood pressure, while pulse transit time had only a weak relationship with that stiffness measure. We therefore propose a new index of arterial stiffness that is independent of blood pressure. This new index closely matched the physiological stiffness measure and showed a strong correlation with it. These findings suggest that pulse transit time alone is not suitable for estimating arterial stiffness from a single hospital measurement, and that blood pressure cannot be reliably estimated from pulse transit time alone because arterial stiffness also affects this relationship. The proposed index may provide a more robust way to characterize atherosclerosis independently of temporary blood pressure changes.