Hematologic evaluation of cardiopulmonary bypass circuits prepared with a novel block copolymer

Background. To decrease the complications associated with cardiopulmonary b ypass, novel biomaterials have been introduced that may be less thrombogeni c than standard synthetic surfaces. Methods. Thirty-four patients undergoing coronary artery bypass grafting we re randomized to bypass using either a control circuit or a circuit prepare d "tip-to-tip" with a triblock-copolymer (polycaprolactone-polydimethylsilo xane-polycaprolactone). Results. There was a progressive increase in thrombin generation in the con trol group during bypass, which was not seen in the test group. The test su rface decreased the release of tissue plasminogen activator and plasmin-alp ha(2)-antiplasmin complex formation (p < 0.005). There was also an increase d platelet count and a decreased platelet activation in the test group, as detected by GMP-140 expression and beta-thromboglobulin release (p = 0.017) . There was also significantly more debris that accumulated on the arterial filter in the control group, as confirmed by scanning electron microscopy. Conclusions. This clinical trial has demonstrated a significant difference in the hematologic effects of the test circuits, with evidence of platelet preservation, decreased fibrinolysis, and decreased thrombin generation. A larger trial would be necessary to establish the clinical relevance of thes e differences. (Ann Thorac Surg 1999;67:689-98) (C) 1999 by The Society of Thoracic Surgeons.