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Abstracts: ASAIO Bioengineering/tissue Engineering Abstracts

A NEW RABBIT MODEL FOR THROMBOGENICITY TESTING OF EXTRACORPOREAL CIRCUITS

Skrzypchak, Amy M1; Dikos, Ashley J1; Bartlett, Robert H1; Annich, Gail M1

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The development of nonthrombogenic artificial surfaces for extracorporeal circulation is ongoing. The present gold standard for anticoagulation is systemic heparinization, which can result in hemorrhagic complications. The rabbit venovenous (VV) model previously used by our lab was technically challenging, required intensive monitoring and a pump. To simplify testing of these surfaces, a rabbit arteriovenous (AV) model was developed. Anesthetized and ventilated 2.5–3.5 kg rabbits were placed on an AV circuit for 4 hours. The rabbits had an intravenous and arterial line to maintain hemodynamic stability and collect hourly blood samples which included arterial blood gases, platelet counts, fibrinogen levels and platelet aggregometry. The AV circuit was constructed of Tygon® tubing with a 14GA angiocatheter for the left carotid artery access and a modified 10 Fr. thoracic catheter for drainage into the right jugular vein. The circuit contained 15cm of ¼ in. I.D. tubing on the arterial side, followed by 6cm of 3/8 in. I.D. tubing, and then 15cm of ¼ in. I.D. tubing on the venous side. The circuit was tested with and without folded PVC sheet within the 3/8 in. tubing to increase the surface area. The rabbits were hemodynamically stable for 4 hours. The model demonstrated 50% platelet consumption and 90% reduced aggregation after 4 hours with or without additional surface area within the chamber. The AV model is significantly thrombogenic but simpler and less labor intensive than the VV model, allowing for simultaneous testing of multiple circuits. The AV appears to be superior to the VV model.

Copyright © 2005 by the American Society for Artificial Internal Organs