Presentation Details
| The risk of recurrent venous thromboembolsim and hemorrhage in the postpartum patient requring anticoagulation Thomas Kiebalo1, 2, Ann Malinowski1, 4, Jose Carvalho1, 5, Nadine Shehata1, 2, 3. 1Mount Sinai Hospital, Toronto, ON, Canada.2Department of Medicine, University of Toronto, Toronto, ON, Canada.3Department of Hematology, University of Toronto, Toronto, ON, Canada.4Department of Obstetrics and Gynecology, University of Toronto, Toronto, ON, Canada.5Department of Anesthesiology, University of Toronto, Toronto, ON, Canada |
Abstract
Background: Current anesthesia guidelines advise for the discontinuation of prophylactic low molecular weight heparin (LMWH) 12 hours prior, and therapeutic LMWH 24 hours prior to the use of neuraxial anesthesia (NA) for obstetrical patients. The first prophylactic dose of LMWH can be administered 12 hours after epidural insertion/spinal anesthesia and at least 4 hours following epidural catheter removal. There remains a paucity of evidence regarding the rates of recurrence of venous thromboembolism (VTE) during this highly procoagulant time. Furthermore, data are scarce on rates of significant bleeding including both postpartum hemorrhage and spinal hematoma in the setting of prophylactic vs. therapeutic anticoagulation. A retrospective single-centre study was designed to assess the risk of VTE as well as rates of significant bleeding in pregnant patients using the current society guidelines. Methods: Individuals from a university-affiliated quaternary referral hospital were assessed from 2013 to 2023. Those who received either prophylactic or therapeutic anticoagulation with LMWH both antenatally and postpartum together with neuraxial anesthesia were included. Medical records were reviewed to determine the indication for anticoagulation and the correspondent dosage of LMWH, the mode of neuraxial anesthesia, mode of delivery, the time of epidural catheter/spinal anesthesia insertion, the time of epidural catheter removal, time of first LMWH injection postpartum, concurrent aspirin use, presence of thrombophilia, relevant laboratory markers (platelet count) and comorbid illnesses. All patients included in our analysis were assessed in either the Hematology or Thrombosis clinic antenatally and were all appropriately counselled on indications for anticoagulation discontinuation at the time of labour according to the current recommendations. The primary outcomes were: frequency of VTE recurrence, spinal hematoma and volume of postpartum blood loss. Results: Of 2634 pregnancies, 251 fulfilled criteria, and 213 had complete data. Median age was 34 years, and median weight was 84 kg. The indication for prophylactic or therapeutic anticoagulation included: estrogen provoked VTE (n=117), other provoked (n=25), unprovoked VTE (n=55), MPNs (n=2), Thrombotic APLA (n=6) and Obstetrical APLA (n=8). Median platelet count at delivery 212 x10(9)/L. 35% were using concomitant ASA antenatally. 57% percent had vaginal delivery (n=112). 154 (72%) had epidural anesthesia, 56 (26%) had spinal anesthesia and three had combined spinal/epidural anesthesia. Median time to restarting LMWH was 8 hours from epidural catheter removal, and 12 hours from spinal anesthesia insertion. There were no spinal hematomas. Median blood loss was 400 mL. One patient who received prophylactic dose LMWH antenatally for a previous estrogen-provoked VTE developed superficial vein thrombosis on postpartum day 1. She underwent spontaneous vaginal delivery, with epidural anesthesia and prophylactic dose LMWH was initiated 13 hours after epidural removal. One patient with a history of remote unprovoked PE who had vaginal delivery and received epidural anesthesia developed early post-partum hemorrhage two hours after prophylactic LMWH post-partum, estimated blood loss of 2000 mL. Conclusions: This study demonstrates a low rate of recurrence of VTE after interruption of anticoagulation and of bleeding. Further prospective perioperative studies are needed to support the safety of the current standard of practice in this patient population.
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No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.