Study Of Angiomax In Infants Under Six Months With Thrombosis

The goals of this study are: 1. To assess the safety of bivalirudin in infants under six months with arterial or venous thrombosis; 2. To determine the dose of bivalirudin required to achieve adequate anticoagulation as measured by the activated clotting time (ACT) or activated partial thromboplastin time (aPTT) in Infants Under Six Months with arterial or venous thrombosis; 3. To determine the outcome of patients on bivalirudin with respect to thrombus resolution and bleeding complications compared to patients on unfractionated heparin (UH) or low molecular weight heparin (LMWH).