Use of argatroban as an alternative anticoagulant in cardiopulmonary support with an oxygenator: experimental study

Argatroban, a selective and competitive antithrombin agent synthesized in Japan, was assessed for use as an alternative anticoagulant for partial venoarterial bypass with an oxygenator, by determining serial changes in hemostatic molecular markers. Fourteen dogs were divided into 3 groups in which partial veno-arterial bypass was carried out: a group in which no anticoagulant was used (group N, n = 3), a group in which 200 IU/kg of bolus heparin was used (group H, n = 5), and a group in which 10 μg/kg per min of intravenous argatroban was used (group A, n = 6). Both thrombin-antithrombin complex and fibrinopeptide A increased significantly in group N; they did not increase in group H. Group A showed high thrombin-antithrombin complex levels and significantly high fibrinopeptide A levels throughout the bypass procedure in comparison to levels in group H. However, plasma fibrinogen was maintained at higher levels in group A than in group H. Platelet count decreased significantly immediately after the start of bypass in groups N and H, but no significant change in platelet count was observed in group A. In conclusion, argatroban at a dose that prolongs activated clotting time to 200 s suppressed thrombin and fibrin generation less effectively than did full-dose heparin. However, excessive consumption of fibrinogen and accelerated fibrinolysis were not observed, and more platelets were preserved, suggesting that argatroban can be used safely in partial cardiopulmonary bypass with an oxygenator.