Abstract
There is a need for new methods to measure the level of arterial stiffness easily at home. A previous report investigating the effect of measurement position on brachial-ankle pulse wave velocity (baPWV) showed that baPWV were higher in the sitting position than in the supine position. This was probably because the increased ankle PWV was associated with increased hydrostatic pressure in the arteries of lower extremities. Therefore, we investigated the effect of measurement position on the cardio-ankle vascular index (CAVI), which is hardly affected by blood pressure. CAVI was measured in 50 healthy males (20-74 years) in five positions: supine, sitting, sitting with the knees flexed at 0°, reclining 50°, and standing. Compared to other positions, CAVI in the supine position was the lowest (P < 0.01); t_b (the time difference between the second heart sound and the notch of the pulse wave in the upper arm) in the supine position was the highest (P < 0.01); and t_<ba> (the time difference between the minimum upper arm and ankle pulse wave pattern values) in the supine position was the highest (P < 0.01). Thus, our results indicated that changes in measurement position reduced pulse arrival time (increasing pulse wave velocity). We also observed a strong correlation between CAVI in the supine position and that in other positions. The present study showed that the measurement position affected CAVI as much as it affected baPWV. Accordingly, correcting for the measurement position would be required when the position differs from supine.
