Blood-material interaction, ex-vivo test for the initial events.

The different tubes affected the tested parameters in different ways. The fibrin and platelet amplitudes are the most sensitive parameters of the RTG-method. A rough surface alterates preferably the platelet activity in the first two milliliters. After about one minute of blood material interaction the amplitudes of fibrin and thrombocytes of all materials have reached the level of the reference blood. The tube with the lowest thrombogenic response to the blood is the polyurethane tube followed by polypropylene, Silastic, polyurethane with the rough surface and finally PVC. In this ex-vivo method the materials are tested under dynamic and nearly physiological conditions. Only one animal is needed for all experiments. No anaesthesia, no anticoagulants are required. The experimental effort and the costs are low. The results are well reproducible although the blood flow might vary slightly. Finally the test results are immediately available.