In vitro investigation of the blood response to medical grade PVC and the effect of heparin on the blood response

This paper reports the results of an investigation into the blood response of polymers in vitro, using non-anticoagulated and heparinised blood and pl asma. The materials studied were regenerated cellulose, (Cuprophan), an acr ylonitrile-allyl sulphonate copolymer (AN69S), and medical grade polyvinyl chloride plasticised with di-2-ethyl-hexyl-phthalate (PVC/DEHP). Blood-mate rial or plasma-material contact was achieved using a parallel plate flow ce ll, and C3a generation and FXII-like activity measured. The results of the study with non-anticoagulated human blood show that PVC/DEHP is a high comp lement activator. C3a concentration in the blood was higher after contact w ith PVC/DEHP than after contact with regenerated cellulose. The introductio n of heparin in the blood induced complex alterations in the blood response . C3a generation could be elevated, decreased, or remain the same, dependin g on the material. The FXII-like activity on the surface of the PVC/DEHP af ter contact with plasma was also higher than the other two polymers. The in troduction of heparin could increase or decrease FXII-like activity, depend ing on material. The patterns of response obtained with non-anticoagulated blood in vitro for AN69S and Cuprophan bore a strong resemblance with patte rns of response obtained in the clinic, whereas those obtained with heparin ised blood in vitro did not. (C) 1999 Elsevier Science Ltd. All rights rese rved.