Introduction - Microsurgery: Advances, Simulations, and Applications - page 26

of research transferred gradually to the recreation of the pumping
function. Currently main issues in the development of the artiicial
heart are the hardware longevity and low weight. One of the most
popular artiicial hearts is TERUMO HEART, which is an implantable
centrifugal pump that works as an auxiliary artiicial heart (Dura
Heart). This equipment works as an alternative left ventricle and
uses magnetic levitation for controlling centrifugal pump impeller
position. This levitation reduces the friction during actuation
and thus increases the life time of pump. The controlled magnetic
levitation of the impeller prevents thrombus formation.
1.3.1.2 Artificial vascular gra
The number of patients suffering from vascular diseases, such
as aneurysm and thrombus, has unfortunately increased due to
modern diet. Artiicial blood vessels have been developed to replace
diseased vessel since 1952. The principal requirements for artiicial
vascular graft are
1. Biocompatibility
2. Exclusive use of non-toxic materials
3. Robustness and compliance
4. Ease of handling
5. Antithrombogenic
6. Reduced blood leakage
TERUMO also developed artiicial blood vessels by using
biocompatible polymer. This technology is successful in clinical
application for large-diameter vascular graft. The prevention of
clot formation in small-diameter artiicial arteries (cross-section
diameter below 6 mm) is still a challenge.
Matsuda et al. have been continuously developing artiicial
vascular graft of small-diameter arteries by the use of biodegradable
polymer [70-72]. In the world's irst report of vascular regeneration,
Shinoka et al . developed regenerated cardiovascular system. Tailor-
made blood vessels scaffold were proposed by Uchida et al . in 2008
[73] and will be explained in detail in Chapter 7.
A tissue engineered blood vessel is commercialized by Cytograft
Inc. It was developed by rolling fibroblasts sheets to produce
vascular grafts with an inner layer lined with patient endothelial
cells for thrombosis prevention. Tissue engineering was integrated
with stent graft technology, by using biological sheets for the stent