Bivalirudin for PCI in HIT

The ATBAT trial was a prospective, open-label study to evaluate the safety and efficacy of bivalirudin in patients with acute HIT or a past history of HIT undergoing PCI (Campbell et al., 2000b; Mahaffey et al., 2003). The primary endpoint was major bleeding within 48 h after completion of the bivalirudin infusion (1.0 mg/kg/h iv bolus followed by 2.5mg/kg/h by iv infusion for 4 h). This dose was later changed to a 0.75 mg/kg/h iv bolus followed by a 1.75 mg/kg/h infusion for 4 h. Secondary endpoints included event rates for components of the primary endpoint and the ACT, aPTT, and platelet counts (at baseline, pre-PCI/post-PCI,

TABLE 7 Theoretical Advantages of Bivalirudin for Treatment of HIT

Feature of bivalirudin

Comment

Avoids need for initial iv bolus; rapid reversal of anticoagulation (useful if patient develops bleeding or if used for intraoperative anticoagulation)3 Minor renal excretion (20%) means that risk of overdosing in renal failure less than with lepirudin; less risk of postoperative bleeding (compared with lepirudin) if used for intraoperative anticoagulation (in case of postoperative renal insufficiency)b Simplifies transition to oral anticoagulation (compared with argatroban)

Reduced risk of allergy and anaphylaxis (compared with lepirudin)

aPossible disadvantages of a short half-life include need for frequent sc administration (e.g., three or four times daily) and rapid loss of anticoagulation (with risk of rebound thrombosis) if prematurely discontinued in patients with acute HIT.

bPossible disadvantage of enzymic metabolism includes loss of anticoagulant action in stagnant blood (implications for cardiac anesthesiology) (see Chapter 19).

Abbreviations: HIT, heparin-induced thrombocytopenia; INR, international normalized ratio; iv, intravenous.

Short half-life (25 min)

Predominant enzymic metabolism

Minimal effect on PT/INR Low immunogenicity and prior to discharge). Clinical success was defined as procedural success without death, emergency bypass surgery, or q-wave MI. Only one of the 52 patients required a blood transfusion (1U), and procedural and clinical success were achieved in 98% and 96% of the patients, respectively. There were no abrupt closures, nor was thrombus formation reported during or after PCI. One patient died of cardiac arrest about 46 h after successful PCI.

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