Hirudin protects from leukocyte/endothelial cell interaction induced by extracorporeal circulation

Background: The clinical complications of Extracorporeal Circulation (ECC) have been linked to disturbances in the microcirculation. In order to preve nt these deleterious effects, a biodegradeable agent to coat the extracorpo real circuit was tested. Methods: Intravital fluorescence microscopy was us ed on the hamster skinfold chamber model in permanently instrumented, awake animals. ECC was introduced via a micro-roller-pump and a silicon tube shu nted between the carotid artery and the jugular vein. The ECC-tube system w as coated with PEG-Hirudin-Iloprost, two additional groups received either Iloprost i.v. (0,8 mg/kg/h) or Hirudin i.v. (1 mg/kg b.w.). Results: ECC fo r 20 minutes resulted in an increase in rolling and adherent leukocytes in postcapillary venules (Roller 9 to 36 [%]; Sticker 24 to 330 [n/mm(2)]). Us e of the coated tube system reduced L/E cell interaction (Roller 9 to 24* [ %], Sticker 28 to 194* [n/mm(2)]; *p<0.05), whereas Hirudin i.v. nearly abo lished it. Conclusions: The protective effects of the coating and of Hirudi n i.v are probably a result of an attenuated activation of the coagulation- fibrinolytic system.