SERPINC1 and hereditary antithrombin deficiency: However, as direct inhibitors of factor Xa, which can exert anticoagulant effects independent of AT III, these drugs may play an important role in the treatment of acute venous thromboembolism and the secondary prevention of patients with AT III deficiency, and do not require regular monitoring of INR, or can be used as follow-up maintenance anticoagulant therapy for patients with AT III deficiency.