///2019 Abstract Details
2019 Abstract Details2019-07-13T07:45:15-05:00

High Dose Unfractionated Heparin In an Antepartum Patient with a History of Thromboembolism

Abstract Number: FCD-312
Abstract Type: Case Report Case Series

Gregory T Palleschi MD1

Pregnancy is a hypercoaguable state. Frequently, antepartum patients receive thromboprophylaxis, particularly if presenting with a thrombophilia. We present a case of a multigravida who received high-dose subcutaneous heparin in the antepartum period and subsequently presented for urgent cesarean section.

This is a 32 year old gravida 3 para 1 with a twin gestation at 24 weeks. She is admitted to the hospital with a cervical dilation of 1-2 cm, but not in labor. Her past medical history is significant for the presence of a pulmonary embolus and a deep venous thrombosis approximately eleven years prior to admission. Treatment consisted of unfractionated heparin, followed by 6 months of warfarin therapy. One year later, she presented with lower extremity deep venous thrombosis complicated by pulmonary embolism. Six months of warfarin therapy was repeated. Testing for thrombophilia yieled negative results. Almost four years later the patient delivered a full term baby girl. During this pregnancy the patient was maintained on lovenox and transitioned to subcutaneous heparin in the last weeks of gestation.

On admission, the patient was transitioned from LMWH to unfractionated subcutaneous heparin. A heparin infusion at a rate of 1600 units/hour, yielded a therapeutic aPTT. Conversion to twice daily subcutaneous dosing was based on this daily intravenous dose, and 19000 units SQ q12 hours was commenced upon termination of the infusion. Follow-up aPTT values were obtained. The q12 hour dose was adjusted to achieve a consistent aPTT value >50 seconds. The final dose of heparin needed to achieve this value was 23,000 units administered subcutaneously every twelve hours.

Approximately eight weeks after initiation of this therapy, the patient was transferred to the labor floor with non-painful contractions and a cervical dilation of 4-5 cm. She presented at 1800 hours and had received subcutaneous heparin, 23000 units at 10 am that morning. The aPTT was 71 seconds. Twin “B” was transverse and the cervix rapidly dilated to 8 cm. An uneventful general anesthetic was performed and cesarean section commenced. Protamine, 50 mg intravenously, was administered prior to incision. The blood loss was estimated at 600 cc and repeat aPTT the next morning was 32 seconds.

Patients are not infrequently anticoagulated on the antepartum floor. The guidelines governing the administration of LMWH and unfractionated heparin vis-a-vis neuraxial analgesia have recently been updated. This case involves the administration of high dose unfractionated heparin subcutaneously over a prolonged period. This differs from IV administration given that the prolongation of effect due to the reservoir of subcutaneous heparin is unknown. Acute reversal with protamine may lead to reheparinization later with the possibility of post-partum bleeding. Management of such patients presents challenges should intraoperative or postoperative bleeding occur.

SOAP 2019