Radial pulse transit time is an index of arterial stiffness

Aortic pulse wave velocity, calculated from pulse transit time (PTT), is often used as an indicator of arterial stiffness and suggested to be standardized for heart rate (HR). This study aimed to determine whether PTT obtained directly from radial arterial waveforms could be used to assess arterial stiffness and the effect of HR on it. Measurements of anthropometric parameters, blood pressure (BP) and radial PTT were taken in 266 apparently healthy adults (113 men and 153 women; age 18-78 years). BP and radial PTT were measured in a subgroup of 11 young subjects (seven men and four women, age 24-35 years) in a 3-month follow-up study, which aimed to investigate the effect of HR changes. Radial PTT was significantly higher in men compared with women (0.116 ± 0.022 s compared with 0.103 ± 0.031 s, P < 0.001). It was inversely related to age in men and women (r=-0.838 and r=-0.804, respectively, P < 0.01 for both). Multiple regression analysis showed that HR was a potent predictor of radial PTT in addition to age, sex and systolic BP. There was no significant change in radial PTT when HR ranged from 60 to 75 b.p.m. A significant decrease was found in radial PTT when HR was up to 80 b.p.m. (P < 0.01). These findings indicate that the simple and easily obtainable radial PTT could be a useful index of arterial stiffness, and HR changes should be considered when it is up to 80 b.p.m.