A natural rubber drainage tube with antithrombogenic lumen surface

A drainage tube was made by radiation vulcanization of a high polymeric substance based on natural rubber elastomers. Pentosan polysulphate sodium bound to a carrier substance (synthetic type 4A or 13X zeolite) was incorporated in the drainage tube which was then tested for its anticoagulant properties during perfusion with Tris buffer solution, citrated plasma, and blood, resp. The amount of pentosan polysulphate sodium released from the tube walls during perfusion with human citrated plasma in an open circulatory system was sufficient to exert an anticoagulant effect on the streaming plasma. This effect was corroborated by prolonged thrombin times and by unclottability in case of recalcified plasma samples in thrombelastographic studies. The antithrombogenicity test according to Chandler in a closed circulatory system revealed thrombus formation times (TFT) of more than 24 h (control: TFT = 1-3 min in native blood).