This invention relates to an antithrombogenic material employed in artificial biocompatible material, such as an artificial blood vessel, or in medical equipment brought into contact with blood.
Recently, with the progress in medical technology, evolution of artificial or prosthetic organs having the function similar to that of a living body is progressing. For example, a medical equipment through which the blood from the living body is caused to flow transiently, such as an artificial dialysis system, or artificial organs, such as artificial blood vessel or artificial heart, are being put to practical usage.
Among the properties required of these medial equipment and artificial organs are biocompatibility and, above all, antithrombogenicity, especially at the portions thereof directly contacted with the blood. Should the artificial material exhibit low antithrombogenic in these portions, platelets tend to be accumulated to coagulate the blood to form blood clots, that is thrombus, which inhibits blood stream or which is moved with the blood stream to cause cerebral thrombosis, myocardial infarction or pulmonary infarction. Thus the formation of blood clots represents a serious problem to the human body.
Under these circumstances, various antithrombogenic materials have been evolved, such as polyurethane-silicone block polymers, heparinated high molecular materials, hydroxy ethyl methacrylate-styrene block polymer, urokinase immobilized high polymer material or plasma treated high molecular weight materials, for use in various fields of applications.
However, the first to fourth of these antithrombogenic material are prepared by chemical synthesis through various steps such as material refining or separation for synthesis with resulting inconveniences in productivity, equipment investments and costs.
The fifth material, which may be produced by physical processes, has a drawback that it presents a non-homogeneous treatment surface.
In short, the conventional antithrombogenic materials leave much to be desired in that the manufacture process is complicated or the product of a uniform quality cannot be produced without considerable difficulties.