HEPARIN SURFACE-COATED HARD SHELL VENOUS RESERVOIRS - EXPERIMENTAL EVALUATION EX-VIVO

The present study was designed for ex vivo evaluation of a heparin coa ted hard shell venous reservoir in comparison to uncoated control rese rvoirs. An open chest bovine right heart bypass model (n=9, bodyweight 72 +/- 6 kg) with passive blood drainage from the right atrium into t he venous reservoir and active retransfusion into the pulmonary artery (roller pump) was selected for this purpose. Clear priming was used f or the open perfusion circuit. No heparin was given before or during t he evaluation period which was scheduled for 6 hours. Reservoir blood flow was at the beginning 3.5 +/- 0.6 l/min for coated versus 3.4 +/- 0.3 l/min for uncoated (NS). After 6 hours, blood flow was 3.3 +/- 0.1 l/min for coated versus 2.7 +/- 0.4 l/min for uncoated (p<0.05). Hema tocrit moved from a baseline level of 30 +/- 2% for coated versus 28 /- 3% for uncoated (NS) to 28 +/- 3% for coated versus 27 +/- 5% for u ncoated (NS) after 6 hours. Prebypass platelet levels of 100% in both groups moved to 84 +/- 3% for coated versus 78+/- 23% for uncoated (NS ) after 6 hours. Activated coagulation time (ACT) before bypass was 14 8 +/- 12 s for coated and 153 +/- 6 s for uncoated (NS). After 6 hours , ACT was 160 +/- 9 s for coated versus 152 +/- 5 s for uncoated (NS). Thrombin time before bypass was 15 +/- 2 s for coated versus 16 +/- 2 s for uncoated (NS). After 6 hours, thrombin time was 17 + 2 s for co ated versus 18 +/- 4 s for uncoated (NS). Baseline antithrombin III le vels were 91 +/- 25% for coated versus 96 +/- 17% for uncoated (NS). A fter 6 hours antithrombin III levels were 95 +/- 23% for coated versus 93 +/- 19% for uncoated (NS). Baseline fibrinopeptide A levels were 2 .6 +/- 0.4 ng/ml for coated versus 2.6 +/- 0.8 ng/ml for uncoated (NS) . After 10 minutes of perfusion fibrinopeptide A moved to 4.8 +/- 0.9 ng/ml for coated versus 8.8 +/- 3.2 ng/ml for uncoated and reached 10. 7 +/- 2.6 ng/ml after 2 hours for coated versus 15.3 +/- 0.1 for uncoa ted (p<0.01). We conclude, that despite the open perfusion mode, the t ested heparin surface coated venous hard shell reservoirs have improve d thromboresistance. Heparin surface coating increases the reservoir f lows and reduces fibrinopeptide A production.