PB1411 - Management of Antithrombin Deficiency in Pregnancy - 2 cases report

Background: Inherited AntiThrombin Deficiency (ATD) is a rare thrombophilia with a high risk of thrombosis (1). As pregnancy is a maintained state of hipercoagulability, the presence of ATD significantly increases the risk of maternal venous thromboembolism (VTE) (2). Some serious gestational complications are associated with ATD (3). Despite prophylaxis with low molecular weight heparin (LMWH), pregnant women could have VTE and may need Antithrombin replacement therapy (ATRT) for anti-Xa peak level>0.5 IU/mL and throught level>0.1IU/mL (4,5).

Aims: Presentation of two clinical cases of ATD management in pregnancy.

Methods: Data from clinical cases followed at Centro Hospitalar Lisboa Norte were collected using their medical records.

Results: Case 1
27 years old woman, 13 weeks gestation, with inherited ATD and a personal history of deep vein thrombosis (DVT) and pulmonary embolism (PE) at the age of 14 (2 weeks after starting the oral contraceptive pill), presented a new episode of DVT while on enoxaparin 40mg/day plus AAS.
She was started on enoxaparin at therapeutic dose (60mg/bid) and 15 weeks later she had a suspected PE, started on 100mg enoxaparin and was referred to our department.
She started anti-Xa and Antithrombin levels monitoring at peak. She needed higher doses enoxaparin and ATRT(graph 1), with no bleeding episodes.

Case 2
21 week pregnant woman diagnosed with a DVT and PE, was admitted at her local hospital and started on therapeutic dose enoxaparin 80 mg/bid. 3 days after she entered the ER with a new DVT episode. A thrombophilia study was performed, which revealed ATD The patient continued therapy with LMWH and started ATRT. The patient is now 33 weeks pregnant on ATRT with no bleeding episodes.

Conclusion(s): ATD is a rare condition with a strong impact in pregnancy. An adequate individualized management, higher anticoagulation doses and ATRT are safe and efficient in preventing VTE.