The goal of this study is to assess the incidence of the composite of thrombotic events (TEs) and thromboembolic events (TEEs) in patients with congenital antithrombin deficiency under when they receive Atenativ for surgical procedures or parturition.
Adult male or female patients ≥18 and ≤80 years of age. Solely in the US, 4 male or female patients between ≥12 and <17 years of age will be enrolled into the PK phase, and subsequently in the treatment phase, if applicable
Documented congenital antithrombin deficiency, defined by plasma activity level of antithrombin ≤60% from medical history
Personal or family history of TEs or TEEs (except for PK patients)
For the Treatment Phase: either a) non-pregnant surgical patients scheduled for elective surgical procedure(s) known to be associated with a high risk for occurrence of TEs or TEEs, or b) pregnant patients of at least 27 weeks gestational age who are scheduled for caesarean section or delivery
Requires emergency surgery or emergency caesarean section
Has undergone surgery within the last 6 weeks
History or suspicion of another hereditary thrombophilic disorder other than antithrombin deficiency (e.g., activated protein C [APC] resistance/Factor V Leiden, Protein S or C deficiency, prothrombin gene mutation [G20210A], or acquired [lupus anticoagulant] thrombophilic disorder)
Malignancies, renal failure (patients on renal replacement therapy), or severe liver disease (aspartate aminotransferase [ASAT] >5 times the upper limit of normal)