Enoxaparin IIb B 646 650 Recommendations apply to administration of IV enoxaparin at the time of PCI for those who have not received prior antithrombin therapy or who have received upstream SC enoxaparin therapy for UA/NSTEMI. An additional dose of 0.3 mg/kg IV enoxaparin should be administered at the time of PCI to patients who have received 2 therapeutic SC doses (eg, 1 mg/kg) or received the last SC enoxaparin dose 8 to 12 h before PCI: Class I; LOE: B. Patients treated with SC enoxaparin within 12 h of PCI should not receive additional treatment with UFH during PCI ( stacking ): Class III: Harm; LOE: B. Anti-Xa inhibitors Fondaparinux III: Harm C 651,652 PCI should not be performed with fondaparinux as the sole antithrombin agent in patients treated with upstream fondaparinux. An additional anticoagulant with anti-IIa activity should be administered. ACT indicates activated clotting time; COR, class of recommendation; CVA, cerebrovascular accident; FDA, US Food and Drug Administration; GP, glycoprotein; GPI, glycoprotein IIb/IIIa inhibitor; IC, intracoronary; IV, intravenous; LOE, level of evidence; MI, myocardial infarction; N/A, not applicable; PCI, percutaneous coronary intervention; SC, subcutaneous; SIHD, stable ischemic heart disease; STEMI, ST-elevation myocardial infarction; TIA, transient ischemic attack; UA/NSTEMI, unstable angina/non ST-elevation myocardial infarction; and UFH, unfractionated heparin. Levine et al 2011 ACCF/AHA/SCAI PCI Guideline e609 with anti-IIa activity should be administered be- cause of the risk of catheter thrombosis.651,652 (Level of Evidence: C) Fondaparinux, a pentasaccharide, is an indirect factor Xa inhibitor but has no effect on thrombin. 