The influence of different heparin surface concentrations and antithrombin-binding capacity on inflammation and coagulation

The corline heparin surface (CHS) used in the extracorporeal circuit during coronary artery bypass grafting is shown to decrease the activation of inflammation and coagulation. Synchrotron radiation studies have shown that a single layer of the CHS may not completely cover the substrate surface. However, a double layer of CHS results in a uniform surface. We investigated the effect of surfaces with different surface concentrations of heparin on cell activation and coagulation compared to an uncoated surface.The CHS is prepared by a conditioning layer of polymeric amine onto which a macromolecular heparin conjugate is attached. We used PVC tubing, uncoated or modified with a single or double layer of the CHS, and circulated fresh whole blood from healthy volunteers in a loop model system at 37°C up to 4 h. Blood was drawn from the loops at different times and activation of inflammation and coagulation was studied by real-time PCR, flow cytometry and ELISA. The activation of leukocytes and platelets and formation of leukocyte–platelet aggregates were reduced by use of the single-layered CHS compared to the uncoated surface. Use of double-layered CHS resulted in significantly reduced cell activation and thrombin generation. Development of the CHS obtained by the double layer of the coating has improved the biocompatibility of the surface.