The use of extracorporeal, based therapies continues to grow (dialysis, ECMO, pheresis, detoxification, etc.) and a persistent problem with extracorporeal blood contact devices is one of thrombus formation following contact with surface of synthetic materials. In every instance the extracorporeal circulation protocol requires systemic anticoagulation to prevent thrombosis. Heparin has been the standard anticoagulant used and is safe and effective in most instances; however, the use of heparin may be associated with adverse side effects such as thrombocytopenia and hemorrhage. Membrane oxygenation in neonates, a successful and growing treatment, can cause intracranial hemorrhage because of heparin use. In Phase I it was shown that modification of the polyalkyl sulfone system yielded polymers with functional activity that could act as a base for attaching pharmaceutically active heparin. These polymers maintained the high gas permeability of the parent compounds. The next generation of artificial lungs, now under development, will require hyperbaric conditions to gain maximum efficiency combined with low water vapor transport and no plasma leakage.
The results of Phase I gives promise that a stable pharmaceutically active heparin can be bound to synthetic materials such as plastics, rubbers, glass and metals. The coatings proposed will be necessary for the new generation of artificial lungs to function efficiently.
