The Anticoagulant Therapy with Bivalirudin to Assist in the performance of percutaneous coronary intervention in patients with heparin-induced Thrombocytopenia (ATBAT) study is a multi-center, open-label, single-arm, registry of patients with new or previous for Heparin-Induced Thrombocytopenia (HIT) or Heparin-induced Thrombocytopenia and Thrombosis Syndrome (HITTS) who require anticoagulation for PCI. In patients with HIT, the platelet count typically begins to decline between 5 and 10 days after exposure to heparin, to an average of about 50×109/L. The most important clinical complication is the paradoxical development of thrombosis (HITTS), most often occurring as proximal deep-vein thrombosis, pulmonary embolism (PE), limb arterial occlusion, and ischemic stroke, but almost any venous or arterial thrombotic event can accompany HIT. The risk of thrombosis is unacceptably high in patients with HIT whose diagnosis is made based on thrombocytopenia alone. Vascular thrombosis occurs in 0.48% of all patients given heparin, but it occurs in 20% of those who develop thrombocytopenia while receiving heparin. From 25% to 37% of patients who develop heparin-induced thrombosis die.
Fifty or more patients suspected of having HIT or HITTS will be treated with bivalirudin. Bivalirudin has been approved by the FDA for use as an anticoagulant in patients with unstable angina undergoing percutaneous transluminal coronary angioplasty (PTCA). Bivalirudin has been used as a substitute for heparin during PCI in over 7,770 patients to date, and in a small number of patients with HIT/HITTS.
The primary endpoint of the study is the composite incidence of major bleeding events during or within 48 hours after stopping bivalirudin treatment (or at hospital discharge, whichever occurs first). Major bleeding events are defined as: a) intracranial bleeding; b) retroperitoneal bleeding; c) bleeding that results in hemodynamic compromise defined as a reduction in systolic blood pressure from baseline to below <90 mm Hg which requires at least one of the following to maintain a sufficient cardiac output : blood or fluid replacement, inotropic support, ventricular assist devices, surgical intervention, or CPR; d) bleeding that requires transfusion of three or more units of whole blood or packed red cells; or e) a decrease in hemoglobin of >3 g/dL, or in hematocrit of >9%.
A secondary endpoint is the occurrence of any complication.
Results (These are the data!)
Primary endpoint: 1/52
Secondary endpoint: 16/52
References
Mahaffey KW, Lewis BE, Wildermann NM, Berkowitz SD, Oliverio RM, Turco MA, Shalev Y, Lee PV, Traverse JA, Rodriguez R, Ohman EM, Harrington RA, Califf RM, for the ATBAT Investigators. The anticoagulant therapy with bivalirudin to assist in the performance of percutaneous coronary intervention in patients with heparin-induced thrombocytopenia (ATBAT) study: Main results. Journal of Invasive Cardiology 2003;15(11):611-616.