The clinical complications of extracorporeal blood circulation (EBC) have been linked to disturbances in the microcirculation. In previous experiments we found in vivo an increased L/E cell interaction following EBC. As a therapeutical approach to prevent these deleterious effects a new agent to coat the tubing system, was used.

Intravital fluorescence microscopy was used on the dorsal skinfold chamber preparation in syrian golden hamsters. EBC was introduced via a micro-roller pump (1 ml/min) and a 60 cm silicon tube (1 mm inner diameter) shunted between the carotid artery and the jugular vein. Experiments were performed in chronically instrumented, awake animals (age: 10-14 weeks, weight: 65-75 g). Control tubes were uncoated, for the experiment a PEG-Hirudin-Iloprost^® coating was used.

Isovolemic EBC for 20 min resulted in an increase in rolling and adherent leukocytes in postcapillary venules. Micro- and macrohemodynamic parameters and functional capillary density were not affected. The use of the coated tube system resulted in a less pronounced induction of leucocyte/endothelial cell interaction. (Table)

L/E interaction in the microcirculation has been established as an indicator of the systemic activation induced by blood contact to synthetic surfaces during EBC. Coating the extra-corporeal circuit reduced the increase in L/E interaction probably as a result of a attenuated activation of the coagulation-fibrinolytic system including a reduced platelet activation.