**A.4 Use of upper arm blood pressure for calibration of carotid arterial pressure waveform**

The use of upper arm pressure for calibrating carotid arterial pressure (diameter) might be criticized. In young adults, the peak pressure in the upper arm is higher than the peak pressures in central predominantly elastic arteries such as the aorta and the carotid artery (amplification). The peak pressures in central arteries increase with age due to increase in arterial stiffness by aging (late systolic peaking). In contrast, there is little or no consistent change in stiffness of the brachial or radial arteries and little change in the peak pressure in the upper arm. Therefore, the difference between central peak pressures and upper arm pressure becomes less significant in the elderly [20]. Ohte et al. [26] reported that the systematic difference between those in 82 patients (age 64.3 9.4 years) remained within the practical range.

### **A.5 Where to set the positions for echo tracking to measure arterial diameter change waveforms**

The relative change in arterial diameter, (Ds Dd)/Dd, measured in an inner layer (e.g., intima) is greater than that measured in an outer layer (e.g., adventitia) due to incompressibility of the arterial wall. Therefore, β is smaller for an inner layer than for an outer layer. In some institutions, β is obtained by echo tracking the intima and in other institutions by echo tracking the adventitia. Then the obtained value of β for a patient may vary with the institution. We obtained β by setting the positions for echo tracking in the adventitia for the following reasons: 1) it is easier to obtain stable tracking. 2) The PWV calculated from the β obtained from the adventitia agrees well with the PWV obtained by a different method [14].

**Author details**

\* and Motoaki Sugawara1,2

1 Tokyo Women's Medical University, Tokyo, Japan

\*Address all correspondence to: nikiwi@cosmos.ocn.ne.jp

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

*Evaluation of the Effect of Increased Arterial Stiffness on Ejection Performance and Pulmonary…*

*DOI: http://dx.doi.org/10.5772/intechopen.89458*

2 Himeji Dokkyo University, Himeji, Japan

provided the original work is properly cited.

Kiyomi Niki<sup>1</sup>

**43**

*Evaluation of the Effect of Increased Arterial Stiffness on Ejection Performance and Pulmonary… DOI: http://dx.doi.org/10.5772/intechopen.89458*
