SURFACE-BONDED HEPARIN.

Abstract

In order to use foreign surfaces in contact with blood without systemic anticoagulation, it is desirable to develop methods of rapidly bonding heparin to the surfaces of implantable substances. A review is given of work on various polymeric materials. Quaternary ammonium salts with three long alkyl groups are water insoluble and are not easily displaced from a surface in contact with an aqueous phase. For this reason, tridodecylmethylammonium chloride (TDMAC) was investigated as a means of attaching heparin to a large number of polymers by a broadly applicable and simple technique. This technique proved to be generally applicable for a large number of different polymers and had the advantage over previous methods of heparinization in its simplicity and speed and also because it enabled the treatment of composite devices containing several different polymers. Thus, an artificial heart device constructed from silicone rubber, polypropylene, and polycarbonate could be heparinized in one simple procedure. Further improvements in the process are described and clinical studies are underway. The results from these studies indicate that the heparinized surfaces have very low thrombogenicity in contact with blood.