Comparing Anti-XA Levels in Post-Cesarean Patients Undergoing Enoxaparin Thromboprophylaxis
Status:
Completed
Trial end date:
2014-03-01
Target enrollment:
Participant gender:
Summary
Pregnant and recently postpartum women are at significantly higher risk of developing a blood
clot in their arms or legs known as a deep venous thrombosis (DVT) and/or a blood clot in
their lungs known as a pulmonary embolism (PE) compared to their non pregnant counterparts.
It is estimated that this risk increases anywhere from 4 to 50 times higher in pregnant
versus non-pregnant women and further increases almost 11 fold in the post partum period.
This risk is almost doubled when the patient undergoes cesarean delivery. In 2011, the
American College of Obstetricians and Gynecologists (ACOG) issued updated guidelines stating
that for patients undergoing cesarean delivery with additional risk factors for clot or
thromboembolism, protective (prophylactic) treatment with low molecular weight heparin (LMWH)
a type of blood thinner should be considered. However, no specific guidelines about which
risk factors should be considered, or what medication doses should be used were provided. The
American College of Chest Physicians (ACCP) Evidence-Based Clinical Practice Guidelines
published in 2012 delineated who should be given prophylaxis based on various risk factors,
however acknowledged that the recommendations were based on weak quality evidence.
ACOG endorses either once or twice a day dosing for high risk patients after delivery and
states that adjustments for obese women should be made on a case by case basis. However,
there are limited studies on the dosing of LMWH in specific subpopulations including post
operative patients, pregnant patients and obese patients. All of these studies have urged
further investigation of the correct dosing for these high risk subjects due to changes
associated with pregnancy and the level of medication in the blood that may put these
patients at higher risk of venous thromboembolism. Many previous studies have shown that
women in these high risk categories do not achieve protective levels of the medication
measured with a laboratory test; anti Xa level. The investigators hypothesize that due to
their dual risk, obese post-operative recently pregnant women may not be adequately protected
with the daily fixed dose and might need more frequent dosing to protect them.
The objective of this study is to assess what proportion of women achieve the desired anti Xa
level with the fixed daily dose versus twice daily weight based dosing (0.5 mg/kg).