Argatroban and Bivalirudin for Perioperative Anticoagulation in Cardiac Surgery
UNFRACTIONATED heparin (UFH) is the mainstay of anticoagulation for cardiovascular surgery, for patients requiring extracorporeal membrane oxygenation (ECMO), initially for ventricular assist devices (VADs), and for postoperative thrombosis prophylaxis. The elimination half-life of heparin is dose dependent and increases from approximately 30 min after a bolus of 25 U/kg, to 60 min with a bolus of 100 U/kg and 150 min with a bolus of 400 U/kg.1 UFH has many advantages in this setting, including the ability to monitor using standard coagulation assays or point of care tests, including activated clotting time (ACT), the ability for safe usage in patients with renal failure, and complete and rapid reversal with protamine. Heparin, unlike other anticoagulants, requires a cofactor antithrombin to inhibit thrombin and factor Xa. One of the potential unique aspects of heparin is that alterations in the heparin dose response can occur. In case of “heparin resistance,” very high or increasing dosages of heparin are required to achieve the targeted anticoagulant effect.1 The most important factors contributing to this condition are critically decreased concentrations of antithrombin, high fibrinogen levels and thrombocytosis.1
Source: Anesthesiology - Category: Anesthesiology Source Type: research
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