**5. Anticoagulation and hemostasis**

To go on CPB, we need to provide an appropriate anticoagulation via unfractionated heparin (300–400 U/kg). A value of ACT at least of 480 s is enough to start the extracorporeal circulation. In case of low response to a full dose of heparin, we can achieve an adequate ACT by administering antithrombin III (AT3), especially when AT3 plasma levels are less than 70%. From 0.5 to 5% of patients with end-stage heart disease can develop HIT (heparin-induced thrombocytopenia), due to repeated heparin exposures related to the placement of IABP, LVADs, or frequent catheter procedures. Alternative anticoagulation, with direct thrombin inhibitors (bivalirudin and argatroban), [8] is recommended in such patients. At the end of organ implantation, once the aortic and right atrium cannulas are removed, we need to guarantee an appropriate heparin reversal with protamine (50 mg of protamine every 50 mg of heparin). We also give the patient 2 g of tranexamic acid at the induction of general anesthesia and 2 g (25–50 mg/kg) with protamine in association with 1 g of gluconate calcium, to avoid hyperfibrinolysis and replace calcium deficiency. Severe bleeding is not a rare condition especially in patients with previous heart surgery. Particularly, in patients with LVADs as bridge to transplant, severe bleeding can often occur due to the large wound area and pretreatment with multiple anticoagulants and platelet inhibitors. If hemostasis is insufficient and the patient is still bleeding, we need to check for coagulation disorders via ROTEM (i.e., hyperfibrinolysis, coagulation factor deficiency, and hypofibrinogenemia) or via TEG and correct the specific deficiency (prothrombin complex concentrate for clotting factor deficiency or fibrinogen concentrate for hypofibrinogenemia). We prefer this approach instead of large dose of fresh frozen plasma, in order to avoid TACO (transfusion-associated circulatory overload), TRALI (transfusion-related lung injury), immune modulation, and increased risk of infections.
