Safety, Pharmacokinetics and Efficacy of an ATIII Concentrate

Inclusion Criteria: * Congenital ATIII deficiency documented by determination of plasma levels of ATIII off all therapies. Specifically, the baseline levels of ATIII activity should be equal to or less than 60%. * Age \>12 years with a body weight of no less than 30 kg. * Have not participated in another investigational study for at least 30 days. For Segment II, enrollment requires a pregnancy/delivery or a surgical procedure (it should be a major surgery although data from a minor surgery will also be collected). * Documented personal history of major thromboembolic or thrombotic event. * Male or female * HIV, HBV, HCV, HAV and PARVO B19 status known prior to entry. * The subject is willing to comply with all aspects of the protocol, including blood sampling, for the duration of the study. * The subject has signed an informed consent form (if at least 18 years old), or the subject's parent or legal guardian has signed the informed consent form. Subjects below the age of 18 years will also be asked to sign an assent form. All consent and assent forms must be approved in advance by the Institutional Review Board of the investigator's institution. * Patients with heparin-associated thrombocytopenia who require anticoagulation with non-heparin containing drugs will be eligible if they can be safely transitioned during the washout period for the Segment I PK study. * If pregnant, a woman must be Parvo B19 IgG antibody positive. Exclusion Criteria: * Acquired deficiency of ATI…