MONITORING OF ANTICOAGULATION IN APROTININ-TREATED PATIENTS DURING HEART OPERATION

Since aprotinin has become extensively used during cardiopulmonary byp ass the maintenance of safe anticoagulation is a concern. Aprotinin af fects anticoagulation measurement by the activated clotting time. Ther efore, a reliable new measurement is needed to monitor anticoagulation during cardiopulmonary bypass. In the present study, we tested the ef ficacy of two alternative measurements in which whole blood clotting w as stimulated by high-dose thromboplastin or by high-dose thrombin. Du ring cardiopulmonary bypass under standardized heparinization, the act ivated clotting time was twofold longer in the aprotinin group than in control group (p < 0.05), whereas high-dose thromboplastin and high-d ose thrombin groups were not significantly affected by aprotinin. In l aboratory tests using blood from healthy volunteers, all methods showe d linear correlation with heparin concentration in the absence of apro tinin (p < 0.05). However, the activated clotting time measurement was prolonged more by heparin when aprotinin was present (p < 0.05), wher eas high-dose thromboplastin and high-dose thrombin measurements were not. Moreover, these measurements were faster and more dependable than the activated clotting time. Therefore, high-dose thromboplastin time and high-dose thrombin time seem to be reliable for monitoring antico agulation when aprotinin is used during cardiopulmonary bypass.