Progress and Problems in Blood-Compatible Polymers

Battelle, Columbus Laboratories 505 King Avenue Columbus, Ohio 43201 

Very shortly after this finding, a concerted effort was begun in 1964 to find or develop thromboresistant pol3rmers. This effort was the biomaterial portion of the Artificial Heart Program of the National Heart Institute, Descriptions of the approaches taken and progress made have been published in some detail. The early work on individual polymers is not described or referenced here because of space limitation. Consult references (2) and (3) for more specific information. These early efforts were in directions such as  

Parallel to the development of thromboresistant and hopefully completely compatible polymers or surface treatments, research proceeded on (a) the development of methods to evaluate blood compatibility, and (b) the understanding of blood-material interactions that define compatibility. The latter would not only contribute to the development of badly needed improved evaluation methods but also form the basis for the development of truly blood-compatible surfaces. The most recent comprehensive review of blood-materials interactions is found in Reference No. 4. 

It was known early that the first reaction when blood contacted a foreign surface was the adsorption of proteins (5) and it was recognized that it was the nature of this protein adsorbate that governed the further reactions that, in toto, governed the compat- 

Decrease in Platelet Aggregates Release of Function and Thromboplastins 

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In moving organs, such as a heart, the durability of the polymer also becomes critical. An artificial heart will undergo about 368 million flexes in a decade but few, if any, polymeric materials can survive this severe a test. (This same problem also exists for heart valve material in addition to the blood compatibility problems.) While much progress has been made on artificial hearts, the fact remains that these devices have not functioned continuously for ten years and they always require an external energy source for the pumping action (usually compressed air). Obviously any cardiovascular device must also exhibit compatibility with the other body fluids and tissues. Several other articles in this book will deal with this area extensively. 

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