Principles of Clinical and Engineering Integration in Hemocompatibility - Biomaterials Science: An Integrated Clinical and Engineering Approach - page 7

8. The need for careful examination of the contribution of adjunct
therapies, such as oral systemic therapy, to the success and failure
of the biomaterial and its implementation in a particular medical
technology [2, 3, 8].
9. The need for assessing the degree of contribution, or lack of contri-
bution, of factors such as individual genetic polymorphism and other
individual specifications to the success or failure of the biomaterial
[5, 6, 8].
10. The need for long-term implanted devices and tissue-engineered
products [1, 2, 60].
11. The issue of contact time with blood may be a particularly important
factor to consider regarding various biomaterials and their respec-
tive medical technologies [1, 2].
Interestingly, there is still a lack of consensus on testing standardization
with respect to hemocompatibility. One reason for this is the need for a more
comprehensive understanding of the physiological mechanisms leading to
materials failure; furthermore, blood interactions have a complex, dynamic,
and unpredictable behavior. There are a multitude of biomaterial-blood inter-
actions, many of them not fully understood. Therefore, evaluation of these
interactions in order to achieve a complete regulatory consensus cannot be
easily performed [1, 2, 60-62].
As with testing, the engineering process of surface modification of biomateri-
als also lacks consensus. This ultimately has clinical implications in choosing
a specific approach for surface modification versus conservative treatments.
Moreover, discussions about short- and long-term morbidity and mortality
related to hemocompatibilities are taking place, questioning the indications for
the minimally invasive implantations of medical devices, such as stents, hav-
ing direct contact with blood, as well as weighing advantages of stents versus a
complete surgical coronary bypass procedure, for example [1, 2, 60-62, 64, 70].
It is beyond the scope of this chapter to encompass the many facets of
hemocompatibility. Instead of focusing on a myriad of details that can be found
in other references, we have focused on particular principles and consider-
ations that should be taken into account when discussing biomaterials and
hemocompatibility, albeit with a strong clinical focus. A key underlying prin-
ciple is to understand the patient's needs. That is, by listening to the patient,
we can ultimately create biomaterials that will have better hemocompatibil-
ity with superior indications for their implantation [2, 4]. In this chapter, we
have chosen to focus specifically on cardiac stents as a reference point, as they
represent an excellent multi-disciplinary example of clinical and engineering
venues coming together, with several clinical trials. An important goal of this
book is also to stimulate readers to suggest additional questions relevant in the
field of biomaterials that integrate clinical and engineering approaches.