**6.1.1 Mechanical properties of artery model**

When considering expanding the stenotic part in the blood vessel as presented in Fig. 14, it is important to know the vascular mechanical properties. Arteries in a living body are always pressured inside. Simultaneously, they are tensed with strain produced along its axial direction by several tens of percent. In this sense, it can be regarded as a thick cylinder being in a multiaxial stress state. It is necessary to assume such a multiaxial stress test to measure mechanical properties of the blood vessel. This means that it is extremely difficult to obtain mechanical properties of the blood vessel because the mechanical properties are associated with various levels and types of blood vessels.

In this study, the pressure strain elastic modulus propounded by (Peterson et al., 1960), which is easy to manipulate, is used. The pressure strain elastic modulus *Ep*,*<sup>v</sup>* of a blood vessel can be expressed by the following equation

Fig. 14. Dimension of blood vessel with stenosis

Fig. 13. Flow of designing stent suitable for diverse clinical manifestation. Designing a stent suitable for diverse clinical manifestation consists of two steps. In the first step, it is possible to design a stent necessary to expand the stenotic part of a blood vessel. In the second step,

**6.1 Design method of stent having suitable mechanical properties to expand stenotic** 

When considering expanding the stenotic part in the blood vessel as presented in Fig. 14, it is important to know the vascular mechanical properties. Arteries in a living body are always pressured inside. Simultaneously, they are tensed with strain produced along its axial direction by several tens of percent. In this sense, it can be regarded as a thick cylinder being in a multiaxial stress state. It is necessary to assume such a multiaxial stress test to measure mechanical properties of the blood vessel. This means that it is extremely difficult to obtain mechanical properties of the blood vessel because the mechanical properties are

In this study, the pressure strain elastic modulus propounded by (Peterson et al., 1960), which is easy to manipulate, is used. The pressure strain elastic modulus *Ep*,*<sup>v</sup>* of a blood

the designed stent is modified to suit the patient's symptom better.

**6.1.1 Mechanical properties of artery model** 

associated with various levels and types of blood vessels.

vessel can be expressed by the following equation

**artery** 

$$E\_{p,v} = \frac{\Delta p}{\Delta D\_o/D\_o} \tag{18}$$

where *Do* is the blood vessel's outer diameter, and *Do* and *p* are the increase in the blood vessel diameter and the increase in the internal pressure respectively. The pressure strain elastic modulus has been used widely in clinical studies. Therefore, many reports on that subject are available. Table 3 presents value of the pressure strain elastic modulus for each type of human blood vessel, extracted from references (Hayashi et al., 1980; Hayashi, 2005; Stratouly et al., 1987; Gow & Hadfield, 1979), with modification.


Table 3. Pressure strain elastic modulus for each type of human artery
