Ion Combined With The Anticoagulant Effect Of Heparin Coating On Extracorporeal Circulation Of Young Pigs

Backgrounds:Activation of coagulation and inflammationsystem is an unavoidable consequence of blood-foreign interaction inconventional cardiopulmonary bypass (CPB). Heparin-coated circuitshave been known to lower such harmful effects and thereby improveclinical outcomes especially in the high-risk patients.This study was designed to observe thromboresistant effects andbiocompatibility of heparin-coating on the blood contacting surface,which would provide information in developing blood-compatibleCPB circuits. Materials and Methods: A full CPB model using amembrane oxygenator and tubing system was constructed in twelvepiglets (25-3 5 kg). The animals were divided into two groups ofcontrol (n=6) and experimer1tal (n?) groups. In the control group,nonheparin-coated circuits were used. Systemic heparin of 3 mg/kgwas given intravenously and a dose of 1.5 mg/kg was added an hourlater In the experimental group, ion-binding heparin-coated circuitswere used and 1mg/kg of systemic heparin was given without anadditional dose. All animals were placed on ti.ull CPB for 2 hours, and梸1?abstractpump flow was maintained at an average of 2 [1mm Observedparameters were CPB priming volume and pump flow, activatedclotting time, complete blood cell counts, serum electrolytes, kidneyand liver function, arterial blood gases, and blood cell changes.Afier completion of CPB in each animal, a piece of the circuit wasstored in 0.2% glutaraldehyde solution for surface scanning electronmicroscopy. Results: Activated clotting time was significantlyshorter in the experimental group throughout the study period (11 7 vs.499 sec at the start of CPB, p=O.OO38, 189 vs. 493 sec at the end ofCPB, p=0.0002). Surface scanning electron microscopy showed thatmarked aggregation of the cellular elements on the blood contactingsurface of the experimental group, which was significantly less onthat of the control group. After 2-hour of CPB, platelet depletion wassignificantly higher in the cc拁trol group than in the experimentalgroup (1.91 X 10扞ml vs. 0.81 X I0?ml, p=O.0013O). There noted nodifferences in white and red blood cells, serum electrolytes, kidneyand liver functions, and arterial blood gases (p=NS).Conclusion:High dose of systemic heparin does not block thrombusformation on the blood-foreign surface in regular CPB circuits, while-4-abstraction-binding heparin coated CPB circuits showed betterbiocompatibility on the blood-foreign contacting surface even under asmaller dose of systemic heparinization~...