Antithrombin III Deficiency in a High-Risk Parturient with Twin Gestation
Abstract Number: F-42
Abstract Type: Case Report/Case Series
Introduction: Pulmonary embolism remains one of the most common causes of maternal death due to the hypercoaguable state of pregnancy. Antithrombin III (AT III) is a protease inhibitor that lyses factor Xa and thrombin. AT III deficiency increases the chance of thrombosis by 60% during pregnancy and 33% in the puerperium.¹ This case describes a parturient with AT III deficiency on Thrombate III® (generic name: AT III [human]) and anticoagulation therapy, complicating administration of neuraxial anesthesia. A literature review revealed one prior case report of Thrombate III® use prior to neuraxial anesthesia administration.²
Case Description: A 36 year-old G1P0 at 33 weeks twin gestation with incidental diagnosis of AT III deficiency, presented for an elective C-section. She had no other symptoms or known thromboembolic events, and was otherwise healthy. She was anticoagulated with enoxaparin and aspirin. She last received enoxaparin 24 hours prior to admission. Laboratory findings revealed normal CBC and coagulation panel. Physical exam was notable for Mallampati class II airway and grossly normal spine amenable to neuraxial anesthesia. One hour prior to the surgery, she received Thrombate III® 2000 IU IV per her Maternal-Fetal Medicine provider recommendation, as fresh frozen plasma (FFP) would not raise her AT III levels sufficiently. After explaining the anesthetic risks of neuraxial blockade, and obtaining informed consent, a single shot spinal was placed atraumatically using bupivacaine 12 mg, fentanyl 20 mcg, and morphine 300 mcg for postoperative pain control. The procedure proceeded uneventfully and enoxaparin was resumed 24 hours after the C-section. Postoperatively, she did not develop any evidence of epidural hematoma, and baseline neurological function returned.
Discussion: This case illustrates the use of Thrombate III® in the setting of neuraxial blockade, of which there is very little experience. It is unclear if Thrombate III® increases the risk of bleeding, but in this patient, the administered dose would, theoretically, only raise AT III levels to low-normal. Per American Society of Regional Anesthesia guidelines, needle placement was deferred 24 hours after the last enoxaparin dose. Additionally, the risk for trauma and bleeding was minimized by placing a single shot spinal versus an epidural with catheter placement.¹ Further research is needed to provide recommendations for safe neuraxial anesthesia when administering Thrombate III®.
1. Horlocker T, et al. Regional Anesthesia in the patient receiving antithrombotic or thrombolytic therapy: American Society of Regional Anesthesia and Pain Medicine Evidence-Based Guidelines (3rd ed.). Reg Anesth Pain Med 2010; 35:64-101.
2. Pamnani A, et al. Neuraxial anesthesia for labor and cesarean delivery in a parturient with hereditary antithrombin deficiency on recombinant human antithrombin infusion therapy. J Clin Anesth 2010 Sep;22(6):450-3.