NOVEL LONG-TERM IN-VIVO HEMOCOMPATIBILITY TEST FOR CIRCULATORY ASSIST DEVICES - A NEW APPROACH TO THE DEVELOPMENT OF ANTITHROMBOGENIC BLOOD CONTACTING SURFACES

Background: Thrombus formation and resulting embolic complications remain a major problem of ventricular assist devices. Therefore, the development of efficient antithrombogenic surfaces has a high priority. However, long-term tests of ventricular assist devices in large animal models are very expensive. Method: We have developed a novel in-vivo test to investigate several coatings of the MEDOS-H1A assist device. This blood pump is completely made of polyurethane. The outflow conduits, a very common location of thrombi, were excised and implanted into the thoracic aorta of pigs. Results: Due to the small diameter of the descending aorta the aortotomy had to be closed with a patch to avoid extreme tension of the vascular tissue. The surgical approach via a left lateral thoracotomy was well tolerated by the animals. The movement of the polyurethane valve provided sufficient blood flow through the implanted conduit without significant pressure gradient. Conclusion: This simple and inexpensive large animal model provides excellent conditions for long-term testing of new antithrombogenic surfaces. Further investigations have to assess it's clinical relevance.

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