Biocompatibility clinical outcomes

Abstract The chapter discusses the advantages and limitations of arterial prostheses (or vascular grafts) in terms of their biocompatibility, biofunctionahty and biostabUity. Criteria for biomaterials selection and prosthesis design that have enabled patients to recover more rapidly without any device-related complications are reviewed, and developments are considered that may lead to future improvements in healing and clinical outcomes for the next generation of vascular prostheses. 

The blend created for tissue engineering scaffolds can also be used as a material for drug delivery. Reddy et al7 reported the development of a bone filler and drug delivery vehicle using a bionanocomposite, which was filled with bone morphogenetic protein, which stimulates bone formation. Besides that, a hydro>yapatite/chitosan nanocomposite was used in the controlled release of vitamins from the matrix. The blending of PHAs could also be used in a similar way since they share the same features, such as the biocompatibility and not causing adverse effects, which produce desirable clinical outcomes. Chan et developed P(3HB)/EtC blends with a... 

In the scientific literature, we often describe the evaluation of biomaterials biocompat-ibUity by tests that should be predictive of the clinical outcome. Such tests make sense from a regulatory standpoint whereby biocompatibility is assessed by a series of tests to determine the potential toxicity resulting from the contact of the components of medical devices or combination products with the body. 

The problem arises when we start employing biocompatibility for describing material properties in contexts other than the regulatory. Statements like the material is known to be biocompatible, biocompatibility was assessed by ceU culture, or biocompatibility was tested by subcutaneous implantation might sound familiar, but what value do they have to predict clinical outcome ... 

There are, however, several reasons this nomenclature is far from suitable in most cases. In fact, this makes little, if any, sense because biocompatibility is contextoal, that is, much more than just the material itself will determine the clinical outcome. This points to one of the weaknesses with definitions predetermining that the material itself is the only determining factor. 

Diagnostic and therapeutical treatments implicate the contact between tissue, blood and the implanted material. In the cardiovascular field, a variety of biomaterial is implanted in heart and vessels, such as catheters, stents, heart valves and sondes for pacemakers and defibrillators. Using polymers for new technologies has been a revolutionary advance in the therapy of cardiovascular disease [47]. Nevertheless, there is increasing evidence that the polymer coating could be responsible for adverse effects (e.g. in-stent-restenosis, stent thrombosis, chronicle foreign body reactions). Therefore, a feasible biocompatible material should provide a complete re-endothelialisation of the surface, less thrombogenicity as well as anti-inflammatory properties in order to improve clinical outcomes. 

Zinc oxide-eugenol is a somewhat old-fashioned material, but it is widely used as an endodontic sealer [18]. It has relatively poor mechanical properties, but is easy to use in the dental clinic [19] and outcomes are good, which explains its continuing popularity. When set, it is biocompatible towards dental hard tissues, though it is cytotoxic towards soft tissues [20]. Zinc oxide-eugenol is susceptible to hydrolysis, which causes the material to decompose and release eugenol. It is this latter substance which is responsible for the cement s adverse effects on soft tissues, but which also makes the material bactericidal. 

---