Heart diseases and especially the ischaemic heart disease,
causes yearly deaths of about 180,000 people in UK and of
more than 500,000 in USA and this is the main reason for
the premature death of middle-aged men and women [74,
75]. Artificial heart is considered to be a solution for this and
they are made up of a pair of substantially seamless,
polyurethane rigid outer housings each having a shape
approximating the combined outer shape of a natural cardiac
ventricle and its associated auricle, with the bases of each of
the housings being bounded together (Fig. 5) [76].
Cardiovascular implants should possess unique blood
biocompatibility to ensure that the device is not rejected due
to adverse thrombogenic (clotting) or hemodynamic blood
responses. Though cardiovascular implants can be fabricated
using natural tissues, the gradual calcification of this
bioprostheses leading to the eventual stiffening and tearing
of the implant is of clinical apprehension. Non-bioprosthetic
implants are fabricated from materials such as pyrolytic
carbon-coated graphite, pyrolytic carbon coated titanium,
stainless steel, cobalt-chrome alloys, cobalt-nickel alloys,
alumina coated with polypropylene and Poly-4-
fluoroethylene [77]. Apart from the limitations on materials
imposed by the requirements of blood biocompatibility and
the problems associated with designs imposed by the need to
optimize blood flow, proper care should be taken in all
respects in order to avoid the risk of a second surgical
procedure. Further, if there is a catastrophic failure of the
implanted device, it will certainly result in the death of the
patient [78].