To avert catheter thrombosis when fondaparinux is used alone in patients undergoing PCI, an anticoagulant with anti-IIa activ- ity is also administered.313 315 One regimen is 85 IU/kg of UFH loading dose at the time of PCI (reduced to 60 IU/kg if a GP IIb/IIIa inhibitor is used concomitantly).314 4.3.2.4. Unfractionated Heparin Studies supporting the addition of a parenteral anticoagulant to aspirin in patients with NSTE-ACS were performed primar- ily on patients with a diagnosis of unstable angina in the era before DAPT and early catheterization and revascularization. See Section 5.1.2.1 for recommendations at the time of PCI. In general, those studies found a strong trend for reduction in composite adverse events with the addition of parenteral UFH to aspirin therapy.316 322 Clinical trials indicate that a weight-adjusted dosing regi- men of UFH can provide more predictable anticoagulation327 than a fixed initial dose (eg, 5000 IU loading dose, 1000 IU/h initial infusion). The recommended weight-adjusted regimen is an initial loading dose of 60 IU/kg (maximum 4000 IU) and an initial infusion of 12 IU/kg/h (maximum 1000 IU/h), adjusted using a standardized nomogram. Argatroban, a direct thrombin inhibitor, is indicated for pro- phylaxis or treatment of thrombosis in patients with heparin- induced thrombocytopenia, including those undergoing PCI.328 Steady state plasma concentrations are achieved in 1 to 3 hours after intravenous administration. Because of its hepatic metab- olism, argatroban can be used in patients with renal insuffi- ciency. The usual dose is 2 mcg/kg per minute by continuous intravenous infusion, adjusted to maintain the activated partial thromboplastin time at 1.5 to 3 times baseline (but not >100 s). 4.3.3. Fibrinolytic Therapy in Patients With Definite NSTE-ACS: Recommendation Class III: Harm 1. 