DESCRIPTION (Investigator's Abstract): This is a Phase I proposal representive support to study enzymatic modification of heparin. In this research, heparin is desulfated - a maneuver which alters the rheology and anticoagulant properties of the heparin. Reduction in sulfation of heparin as it passes through recirculation shunts during surgery would allow for return of heparin to the patient in a form which does not constitute an anticoagulant, thus avoiding the hemorrhagic complications which sometimes occur in heparinized extracorporeal apparatus. In phase I of the work, feasibility of enzymatically desulfating heparin will be carried out. Sulfatase enzymes will be used. If the modified heparin preparation is altered in its anticoagulant a shunt device which will enzymatically desulfate the heparin. A small column will be placed in the bypass apparatus, through which blood will flow. The column will contain immobilized sulfatase enzymes. The outlet of the device will lead back into the patient with a blood preparation which is oxygenated and safe from the standpoint of having properties which could induce hemorrhage.